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Infrared and Raman characteristic group frequencies table and charts
... With an increase in the proportion of PLA in the mixture, this band moves to higher values (from 2995 to 2997 cm −1 ). The next band belongs to the symmetric stretching of C-H in CH3, which is located at a lower wavelength than that of the asymmetric stretching (from 2926 to 2943 cm −1 ) and is specific for PLA [48][49][50]. Also, the asymmetric stretching of C-H in CH2, which occurs in PCL, is specific for this interval. Symmetric stretching of C-H in CH2 of PCL occurs at 2862 cm −1 [51,52]. ...
... With an increase in the proportion of PLA in the mixture, it moves towards lower values, so in samples with pure PLA, this band appeared at 2854 cm −1 . The next visible band represents the stretching of the C=O bond, which is characteristic of polyester materials such as PLA and PCL [50]. It appears in the interval from 1725 to 1745 cm −1 . ...
... Asymmetric and symmetric stretches of the CH3 group, specific for PLA, appear at 1452 and 1357 cm −1 for pure PLA, and with the addition of PCL in the mixture, these values shift to 1456 and 1363 cm −1 for samples with 50% of the proportion of PCL in the mixture. C-O-C asymmetric and symmetric stretches in PLA are visible at values around 1180 and 1080 cm −1 [48][49][50]. Furthermore, in samples PLA/PCL/SiO2 50/50/0, PLA/PCL/SiO2 50/50/1, and PLA/PCL/SiO2 50/50/3, a band at 1236 cm −1 corresponding to C-O-C asymmetric stretching of PCL can be observed [53]. ...
A quantitative analysis of the morphology, as well as an analysis of the distribution of components and surface/interfacial properties in poly(lactic acid)(PLA) InegoTM 3251D, poly(ε-caprolactone) (PCL) Capa 6800 and nano-silica (SiO2) Aerosil®200 blends, was conducted in this research. The study aimed to improve the understanding of how PLA, PCL, and nano-SiO2 interact, resulting in the specific morphology and surface properties of the blends. Samples were produced by varying the concentration of all three components. They were analyzed using SEM, EDS mapping, water contact angle measurements, surface free energy calculation, adhesion parameter measurements, and FTIR-ATR spectroscopy. The results showed that the addition of SiO2 nanoparticles led to an increase in the contact angle of water, making the surface more hydrophobic. SEM images of the blends showed that increasing the PCL content reduced the size of spherical PCL elements in the blends. FTIR-ATR analysis showed that SiO2 nanoparticles influenced the structure ordering of PLA in the blend with equal portions of PLA and PCL. In the samples with a higher PCL content, the spherical elements present in the samples with a higher PLA/PCL ratio have been reduced, indicating better interactions at the interface between PLA, PCL, and SiO2. SEM-EDS mapping of the PLA/PCL 100/0 blend surfaces revealed the presence of SiO2 clusters and the silicon (Si) concentration reaching up to ten times higher than the nominal concentration of SiO2. However, with the addition of 3% SiO2 to the blend containing PCL, the structure became more granular. Specifically, Si protrusions in the sample PLA/PCL 90/10 with 3% SiO2 displayed 29.25% of Si, and the sample PLA/PCL 70/30 with 3% SiO2 displayed an average of 10.61% of Si at the protrusion locations. The results confirmed the affinity of SiO2 to be encapsulated by PCL. A better understanding of the interactions between the materials in the presented blends and the quantitative analysis of their morphology could improve the understanding of their properties and allow the optimization of their application for different purposes.
... The peak at 3466 cm − 1 corresponds to the stretching of H-OH bonds, while the peaks at 2916 cm − 1 and 2849 cm − 1 , correspond to the stretching of CH 2 groups. The peak at 1467 cm − 1 is due to the bending of CH 2 groups, which are indicative of a polar environment [53,54]. Additionally, the peak at 1216 cm − 1 corresponds to the skeletal vibration involving the S-O bond of the bridge, the peak at 1079 cm − 1 corresponds to the stretching of C-C bonds, and the peak at 824 cm − 1 corresponds to the asymmetric bending of CH 2 group and C-H bonds [53,54]. ...
... The peak at 1467 cm − 1 is due to the bending of CH 2 groups, which are indicative of a polar environment [53,54]. Additionally, the peak at 1216 cm − 1 corresponds to the skeletal vibration involving the S-O bond of the bridge, the peak at 1079 cm − 1 corresponds to the stretching of C-C bonds, and the peak at 824 cm − 1 corresponds to the asymmetric bending of CH 2 group and C-H bonds [53,54]. ...
... The broad band spanning the range of 3000-3600 cm − 1 corresponds to the stretching vibrations of O-H bonds involved in hydrogen bonding, indicative of the presence of hydrophilic groups in SDBS that contribute to its surfactant properties. The band at 2923 cm − 1 is attributed to the asymmetric stretching of C-H bonds in the SDBS alkyl chain, specifically indicating the presence of the dodecyl group within the surfactant molecule [54]. Additionally, the band at 2853 cm − 1 corresponds to the symmetric stretching of C-H bonds in the methylene groups of the alkyl chain [55]. ...
Efficient management of sewage sludge from wastewater treatment plants (WWTPs) are crucial to obtain industrial value-added products and reducing environmental impact. Thermal hydrolysis, coupled with surfactants to enhance solubilisation, offers a promising approach for sewage sludge treatment. This study assessed the impact of four surfactants: sodium dodecyl sulphate (SDS), sodium dodecylbenzenesulfonate (SDBS), cetyl tri-methyl ammonium chloride (CTAC), and tetraethylammonium chloride (TAC) on thermal hydrolysis of sewage sludge. The addition of anionic surfactants (SDS and SDBS) significantly increased biomolecule production, with proteins, humic-like substances, carbohydrates, and DNA concentrations reaching 6018 ± 28 mg/L (306 mg/ gVSS o), 2496 ± 103 mg/L (127 mg/gVSS o), 1822 ± 4 mg/L (93 mg/gVSS o), and 389 ± 3 mg/L (20 mg/gVSS o), respectively, after 155 min of thermal hydrolysis. Low levels of surfactants (10 and 50 mg/gVSS o) also led to a substantial increase in the readily biodegradable fraction of hydrolysed sewage sludge, reaching up to 90 %. Additionally, surfactant-assisted hydrolysed sewage sludge proved to be a favourable substrate for protease production using Bacillus licheniformis. The optimal enzymatic activity of 678 ± 14 U/mL was achieved when CTAC was added at a concentration of 10 mg/gVSS o. In summary, this study evaluated an innovative approach to enhance the solubilisation of biomolecules from sewage sludge using surfactant-assisted thermal hydrolysis. This methodology not only positively affected biodegradability but also proved to be suitable for potentially producing valuable industrial products like proteases through fermentation with B. licheniformis, thus offering a new strategy for the sustainable treatment of sewage sludge.
... The FTIR spectra of the raw and extruded conductive TPU filaments are presented in Fig. 11. The findings substantiated the existence of distinctive functional groups typically associated with poly-(ester urethane)-s, aligning with the interpretation presented in prior works by Silverstein et al. [83] and Yiligor et al. [84]. The FTIR spectra of both the raw and conductive TPU exhibit a close resemblance. ...
... In both spectra, the observed peaks falling within the range of 2941-2863 cm − 1 are related to the symmetric and asymmetric stretching vibrations associated with aliphatic CH2 and CH3 groups within the TPU molecular structure. Furthermore, the pronounced signals within the spectral region of 1733-1685 cm − 1 can be attributed to the C --O bonds stretching vibrations, encompassing both hydrogen-bonded and non-hydrogen-bonded configurations, particularly within the macro-diol ester groups [83]. ...
... Additionally, the stretching vibrations of the urethane group (-NH-(C --O)-O-) were evident at 1165 cm − 1 . Furthermore, the peaks falling within the range of 1135-947 cm − 1 were indicative of the stretching vibrations associated with hydrogen-bonded (-C-(C --O)-O-) moieties [83]. Furthermore, the peaks in the range of 873-863 are associated with bonding vibrations of C-H out-of-plane bending, NH, CH2, OH scissoring and wagging. ...
In this study, a novel multifunctional grid-shaped polymeric composite (MGPC) with reinforcing, autonomous strain, stress, and damage sensing and localizing in addition to targeted heating capabilities, has been developed. Distinct from preceding composites, this grid synthesizes these features collectively for the first time and concurrently addresses current challenges in multifunctional composites, such as environmental impact, data reliability, complexity, and production costs. The fabrication process entails 3D printing an electrical circuit with conductive filaments within a polylactic acid (PLA) host polymer. The conductive filament was composed of a thermoplastic polymer (TPU) infused with carbon nanotubes (CNT)-grafted carbon fibres (CFs) produced via chemical vapour deposition. The mechanical, microstructural, and electrical properties of the grid elements and cementitious slabs reinforced with MGPC were comprehensively examined. The MGPC's performance in traffic flow monitoring, mechanical behaviour prediction, and damage localization was assessed through wheel tracking, asymmetric punch tests, piezoresistivity response evaluation, and digital image correlation techniques. Furthermore, the self-warming ability of the MGPC in cementitious composites was investigated using different voltages. The extruded TPU containing CNT-grafted CFs exhibited an electrical percolation threshold of approximately 5.0 wt%, resulting in a conductivity of around 70 S/m for the filaments. Incorporating MGPC as reinforcement within cementitious composite slabs led to notable enhancements, with flexural strength increasing by approximately 15 % and failure strain by up to 350 %. Wheel tracking tests revealed changes in the electrical: 5.8 % for 520 N and 7.8 % for 700 N wheel loads, with roughly 5.0 % average error in velocity detection. Transverse elements precisely detected wheel locations demonstrating the MGPC capabilities in accurately detecting wheel speed weight, and location. The study established strong correlations between electrical resistance changes, mechanical behaviour, and damage detection, affirming the MGPC's reliability and efficacy for damage monitoring and localization. The cementitious slab reinforced with MGPC reached around 52 • C through a 20 V direct current, with a heating rate of 0.25 • C/s and a power density of 142 W/m 2, showing its potential for practical applications such as self-healing and de-icing. However, design parameters such as mesh and conductive circuit configuration, long-term performance, and Life Cycle Assessment need further investigation.
... C=O vibrates in the 1770-1665 cm -1 range for amides in solution. Both N-H and C-N vibrate in the 1550-1510 cm -1 range [Socrates, 2001]. However, these vibrations change in proteins because hydrogen bonds (Hbonds) between C=O and N-H groups effectively change the coupling strengths k. ...
... Because of the large number of overlapping bands in the fingerprint region, assigning these bands is difficult. In accordance with literature, one possible origin of the bands is the stretching vibrations of C-O-R groups, where R represents a manifold of possible extensions [Socrates, 2001]. Fortunately, the spectral ranges used here for plaque analysis are not affected by these changes. ...
... v. The Amide II band shape is also sensitive to the secondary structure of proteins [Socrates, 2001]. This effect is in fact visible in FTIR difference spectra of plaques in figure 3.9C. ...
Alzheimer’s disease (AD) is a devastating neurodegenerative disorder that
affects millions of individuals worldwide. One of the hallmark features of AD
is the accumulation of amyloid beta (Aβ) plaques in the brain. The role of Aβ in
the disease has been a topic of debate in the scientific community. The amyloid
hypothesis states that an imbalance between Aβ production and clearance
leads to the accumulation of Aβ polymorphs such as oligomers and fibrils in
the form of plaques. However, the exact mechanisms underlying Aβ plaque
development remain elusive.
The primary goal of this thesis is to gain a better understanding of the
distribution of Aβ polymorphs in plaques. Post mortem brain tissue sections
were examined using infrared (IR) microscopy, which allows for a label-free
investigation of the tissue. Aβ oligomers were detected in diffuse plaques
based on their characteristic IR signature of antiparallel β-sheet structures. The
proportion of Aβ fibrils increases with the progression of plaque compaction,
providing insights into the developmental sequence of plaques. The results
were validated using orthogonal, structure-sensitive methods, providing a
comprehensive picture of Aβ structure in plaques.
Furthermore, an innovative approach to label-free extraction of plaques from
brain tissue sections was developed. Previously, immunohistochemistry (IHC)
was required, which is time-consuming and can negatively affect the properties
of the sample. Here, a neural network was successfully trained to precisely and
reliably recognize plaques solely using IR microscopy. This makes chemically
untreated plaques accessible for further analytical methods, opening the way
for new insights into the molecular composition of plaques.
This thesis addresses the need for new diagnostic biomarkers and therapeutic
approaches for AD. The high-resolution insight into the distribution of Aβ polmorphs in plaques and the label-free extraction of plaques using IR imaging
contribute to the understanding of AD pathology. The contributions made
here could lead to advances in the diagnosis of AD and pave the way for the
development of new treatment strategies.
... Figure 4 shows the spectra of the initial powders of pectin (DE: 10%) and chitosan (DD: 80%), as well as suspensions NP-01-01 and NP-01-05 and material based on pectin of 0.5 wt.% and chitosan of 0.1 wt.%. Band assignment shown in the spectrum is made for the chitosan according to [37,38] and pectin according to [39,40]. Most of the peaks characterizing both polysaccharides retain their positions on the spectra of polyelectrolyte complexes (Figure 4(3-5)). ...
... Table 2. FT-IR bands and their assignments. Correlation of lines was carried out on the basis of [37][38][39][40]. ...
Conventional chemotherapeutic approaches currently used for brain tumor treatment have low efficiency in targeted drug delivery and often have non-target toxicity. Development of stable and effective drug delivery vehicles for the most incurable diseases is one of the urgent biomedical challenges. We have developed polymer nanoparticles (NPs) with improved temozolomide (TMZ) delivery for promising brain tumor therapy, performing a rational design of polyelectrolyte complexes of oppositely charged polysaccharides of cationic chitosan and anionic pectin. The NPs’ diameter (30 to 330 nm) and zeta-potential (−29 to 73 mV) varied according to the initial mass ratios of the biopolymers. The evaluation of nanomechanical parameters of native NPs demonstrated changes in Young’s modulus from 58 to 234 kPa and adhesion from −0.3 to −3.57 pN. Possible mechanisms of NPs’ formation preliminary based on ionic interactions between ionogenic functional groups were proposed by IR spectroscopy and dynamic rheology. The study of the parameters and kinetics of TMZ sorption made it possible to identify compounds that most effectively immobilize and release the active substance in model liquids that simulate the internal environment of the body. A polyelectrolyte carrier based on an equal ratio of pectin–chitosan (0.1% by weight) was selected as the most effective for the delivery of TMZ among a series of obtained NPs, which indicates a promising approach to the treatment of brain tumors.
... This alteration is a consequence of the coordination and subsequent attenuation of the N−H bond, distinct from the free NH 3 + , as illustrated in Figure 1E. 60 A similar phenomenon was evident in the bands associated with the carboxylic groups. The band situated at 1586 cm −1 (asymmetric C�O stretching) undergoes a shift to 1618 cm −1 , while the band at 1409 cm −1 (symmetric C−O stretching) likely shifts to a lower frequency around 1390 cm −1 , in line with reports on coordination complexes. ...
... The band situated at 1586 cm −1 (asymmetric C�O stretching) undergoes a shift to 1618 cm −1 , while the band at 1409 cm −1 (symmetric C−O stretching) likely shifts to a lower frequency around 1390 cm −1 , in line with reports on coordination complexes. 60 Various bands emerging below 550 cm −1 could be attributed to the Cu−O and Cu−N bonds established within the CuHARS material ( Figure 1F). These observations substantiate the coordination of L-cystine to Cu 2+ through its amino and carboxylic groups, forming a metal−organic complex. ...
Copper−cystine-based high aspect ratio structures (CuHARS) possess exceptional physical and chemical properties and exhibit remarkable biodegradability in human physiological conditions. Extensive testing has confirmed the biocompatibility and biodegrad-ability of CuHARS under diverse biological conditions, making them a viable source of essential Cu 2+. These ions are vital for catalyzing the production of nitric oxide (NO) from the decomposition of S-nitrosothiols (RSNOs) found in human blood. The ability of CuHARS to act as a Cu 2+ donor under specific concentrations has been demonstrated in this study, resulting in the generation of elevated levels of NO. Consequently, this dual function makes CuHARS effective as both a bactericidal agent and a promoter of angiogenesis. In vitro experiments have shown that CuHARS actively promotes the migration and formation of complete lumens by redirecting micro-vascular endothelial cells. To maximize the benefits of CuHARS, they have been incorporated into biomimetic electrospun poly(ε-caprolactone)/gelatin nanofiber aerogels. Through the regulated release of Cu 2+ and NO production, these channeled aerogels not only provide antibacterial support but also promote angiogenesis. Taken together, the inclusion of CuHARS in biomimetic scaffolds could hold great promise in revolutionizing tissue regeneration and wound healing.
... An initial material characterization was conducted using micro−ATR−FTIR analysis to confirm the chemical composition of the paints. The spectra are presented in Figure 2. Table 2. [29,30]. ...
... For the fluorescent blue spray (AcrFB), in addition to the typical peaks of the acrylic binder (1728, 1486, 1455, 1241, 1148, 1066, 842 cm −1 ), the spectrum revealed the presence of another polymer, a poly(aryl sulfonamide), having characteristic peaks at 3367 and 3280 cm −1 for the N-H stretching, 1323 cm −1 for the antisymmetric vibrations of the sulphonyl group, and 1557 and 812 cm −1 for the vibrations of the aromatic rings [30]. This polymer serves as a carrier for the fluorescence pigment. ...
Contemporary murals and street art play a critical role in urban culture, serving as platforms for social activism and reflecting the vibrancy of city life. This study within the SuperStaAr project framework examines the challenge of graffiti removal while safeguarding the original synthetic paint layers. Through a detailed investigation using Q-Switch and Long Q-Switch lasers (Nd:YAG), we evaluate the effectiveness and safety of laser cleaning techniques on both unaged and artificially aged mural mock-ups. The initial findings highlight the Q-Switch and Long Q-Switch lasers as promising for removing graffiti without compromising the paint integrity. Our assessment criteria—encompassing residue presence, surface roughness, color changes, cleaning effectiveness, and pigment pickup—were validated through empirical evaluation and supported by colorimetric, micro–ATR–FTIR, and Py–GC/MS analyses. Notably, the incorporation of a passive sampling system for Py–GC/MS analysis facilitates a deeper understanding of the ablated materials without direct sampling from the artwork. This research contributes a foundational framework for the evaluation of laser cleaning in mural conservation, emphasizing the importance of tailored strategies to enhance the sustainability of urban art conservation efforts.
... Frontiers in Bioengineering and Biotechnology frontiersin.org buffer which were contained in all samples can be traced to the bands at 1249 and 1470 cm -1 indicative for Tris and EDTA (Socrates, 2004). These bands remained roughly constant over the course of a precipitation experiment as only the AMS concentration was gradually increasing. ...
... The AMS contribution was caused by the residual amounts of AMS after buffer exchange. As the peak profiles of the two spiking solutions in the protein fingerprint region differed slightly from one another and the amide bands are commonly used Raman markers for higher-order structures (Socrates, 2004), the ratio of selected amide bands are presented in Figures Figure 5D. In summary, the differences in protein-associated Raman bands of the two spiking solutions underline structural differences between VLPs and HCPs. ...
Virus-like particles (VLPs) are a promising class of biopharmaceuticals for vaccines and targeted delivery. Starting from clarified lysate, VLPs are typically captured by selective precipitation. While VLP precipitation is induced by step-wise or continuous precipitant addition, current monitoring approaches do not support the direct product quantification, and analytical methods usually require various, time-consuming processing and sample preparation steps. Here, the application of Raman spectroscopy combined with chemometric methods may allow the simultaneous quantification of the precipitated VLPs and precipitant owing to its demonstrated advantages in analyzing crude, complex mixtures. In this study, we present a Raman spectroscopy-based Process Analytical Technology (PAT) tool developed on batch and fed-batch precipitation experiments of Hepatitis B core Antigen VLPs. We conducted small-scale precipitation experiments providing a diversified data set with varying precipitation dynamics and backgrounds induced by initial dilution or spiking of clarified Escherichia coli-derived lysates. For the Raman spectroscopy data, various preprocessing operations were systematically combined allowing the identification of a preprocessing pipeline, which proved to effectively eliminate initial lysate composition variations as well as most interferences attributed to precipitates and the precipitant present in solution. The calibrated partial least squares models seamlessly predicted the precipitant concentration with R ² of 0.98 and 0.97 in batch and fed-batch experiments, respectively, and captured the observed precipitation trends with R ² of 0.74 and 0.64. Although the resolution of fine differences between experiments was limited due to the observed non-linear relationship between spectral data and the VLP concentration, this study provides a foundation for employing Raman spectroscopy as a PAT sensor for monitoring VLP precipitation processes with the potential to extend its applicability to other phase-behavior dependent processes or molecules.
... A broad band with a wavenumber around 3330 cm −1 was assigned to the stretching vibration of the O-H group. The subtle bands with wavenumbers at 2120, 2112 and 2110 cm −1 correspond to the stretching vibration of a C-H bond, and the stretching band with wavenumber at 1641 cm −1 was assigned to the asymmetric stretching vibration of the C = O group (28,29). Subtle displacements were detected in bands corresponding to the stretching vibration of the O-H (3330 to 3326 cm −1 ) and the C-H bonds (2120-2112 to 2110 cm −1 ) in the AuNPs samples (Figure 8, blue line) compared to the control (Figure 8, red line). ...
... By contrast, in the FTIR spectrum of the AuNPs-exposed endospores the band corresponding to amide I group was absent and the corresponding to amide II is slightly shifted to 1544 cm −1 and with lower intensity in comparison with the rest of the bands present in the spectra, whereas the bands at 1742 and 1713cm −1 assigned to vibrational signals of the functional groups carbonyl and ketone present in ester groups of lipids and nucleic acids, were also detected (31). A band with a wavenumber at 1172 cm −1 was assigned to the S = O stretching sulfone group (28,31). Along with this band associated with the sulfone, another band appears in the spectrum centered at 1060 cm −1 , this band corresponds to vibrational modes associated with ring vibrations and the coupling between the S−O stretching vibration of the (SO 3 ) 2− groups (32) and the R-SOH sulfenic group (33). ...
Gold nanoparticles (AuNPs) have a wide range of applications due to their optoelectronic properties. Particularly, biological synthesis of AuNPs highlights due to the advantages related to the environmental care and the stabilization provided by capping biomolecules during biosynthesis. The antimicrobial activity of AuNPs was reported, however, their activity against resistant structures such as bacterial endospores have not been evaluated. This work shows the extracellular biosynthesis of AuNPs using Epicoccum nigrum (Au1-8) throughout an ecofriendly, simple, and efficient method. Physicochemical characterization revealed that stable quasi-spherical AuNPs in a range size of 2 to 30 nm, with crystal structure and metallic Au⁰ composition were obtained. The AuNPs sporicidal activity against Bacillus subtilis endospores was evaluated by its exposure to 300 mg/L AuNPs during 48 h, which produced a decrease of 90.6% of the endospore germination. The analysis of the endospore-AuNP interaction by scanning electron microscopy (SEM) and infrared (IR) spectroscopy revealed injury of the endospore coat and lysis. These results are promising for the advance in the development of low-aggressive agents used for environmental decontamination regimens against pathogenic bacterial spores, or even as an alternative for the treatment of illnesses produced by endospore-former causative agents of food spoilage/poisoning and human diseases.
... The process of thermal cyclization for PA-4MeO-6F to PBI-4MeO-6F was controlled using FTIR spectroscopy (Figure 7). The absorption bands of the amide groups, amide I (1667 cm −1 ) and amide II (1530 cm −1 ), as well as those in the region between 3200 and 3400 cm −1 , which are attributed to the NH groups, completely disappeared [30]. ...
... The PBI-4MeO-6F films after thermal cyclization possess a sufficient tensile strength of 75 ± 5 MPa, an elongation at break of 8 ± 2%, and a Young's modulus of 1500 ± 100 MPa. According to the thermogravimetric analysis (TGA) and differential thermal analysis The absorption bands of the amide groups, amide I (1667 cm −1 ) and amide II (1530 cm −1 ), as well as those in the region between 3200 and 3400 cm −1 , which are attributed to the NH groups, completely disappeared [30]. ...
High-temperature polymer-electrolyte membrane fuel cells (HT-PEMFCs) are a very important type of fuel cells since they operate at 150–200 °C, making it possible to use hydrogen contaminated with CO. However, the need to improve the stability and other properties of gas-diffusion electrodes still impedes their distribution. Self-supporting anodes based on carbon nanofibers (CNF) are prepared using the electrospinning method from a polyacrylonitrile solution containing zirconium salt, followed by pyrolysis. After the deposition of Pt nanoparticles on the CNF surface, the composite anodes are obtained. A new self-phosphorylating polybenzimidazole of the 6F family is applied to the Pt/CNF surface to improve the triple-phase boundary, gas transport, and proton conductivity of the anode. This polymer coating ensures a continuous interface between the anode and proton-conducting membrane. The polymer is investigated using CO2 adsorption, TGA, DTA, FTIR, GPC, and gas permeability measurements. The anodes are studied using SEM, HAADF STEM, and CV. The operation of the membrane–electrode assembly in the H2/air HT-PEMFC shows that the application of the new PBI of the 6F family with good gas permeability as a coating for the CNF anodes results in an enhancement of HT-PEMFC performance, reaching 500 mW/cm2 at 1.3 A/cm2 (at 180 °C), compared with the previously studied PBI-O-PhT-P polymer.
... The peaks of plasma-treated GAC after 1 h spectrum shifted some new wavenumbers at 1360 cm −1 , which is assigned to O-H in-plane bending of carbohydrates [61], 611 cm −1 is ascribed to O-H out-of-plane bending [61], and 1576 cm −1 is associated to the -COO-asymmetric stretch of carboxylic acid [61], which are indicators of NOM components being adsorbed, as they represent typical FGs in NOM. Since PFOA is primarily characterized by its C-F bonds in the region of 1290-1010 cm −1 [62], it was found that only one peak was discovered at 1256 cm −1 . Indicating that within The higher PDP led to a more extensive surface modification of GAC. ...
... The peaks of plasma-treated GAC after 1 h spectrum shifted some new wavenumbers at 1360 cm −1 , which is assigned to O-H in-plane bending of carbohydrates [61], 611 cm −1 is ascribed to O-H out-of-plane bending [61], and 1576 cm −1 is associated to the -COO-asymmetric stretch of carboxylic acid [61], which are indicators of NOM components being adsorbed, as they represent typical FGs in NOM. Since PFOA is primarily characterized by its C-F bonds in the region of 1290-1010 cm −1 [62], it was found that only one peak was discovered at 1256 cm −1 . Indicating that within the first hour, the GAC has a higher affinity for NOM adsorption instead of PFOA. ...
Perfluorooctanoic acid (PFOA) contamination in water sources poses significant environmental and health concerns. The kinetic, equilibrium, and thermodynamic features of PFOA adsorption in the existence of natural organic matter (NOM) were thoroughly investigated in this work using granular activated carbon (GAC) modified by dielectric barrier discharge (DBD) plasma. The impacts of DBD plasma parameters on the adsorption process were systematically examined. The results demonstrated that GAC modified by DBD plasma exhibited enhanced adsorption performance for PFOA, even in the presence of NOM. The optimal condition for plasma-treated GAC was achieved with 20 min of plasma treatment time and 100 W of plasma power, resulting in 92% PFOA removal efficiency in deionized water (DIW) and 97% removal efficiency in Chao Phraya River water (CPRW). A kinetic investigation using the pseudo-first-order model (PFOM), the pseudo-second-order model (PSOM), and the Elovich model (EM) indicated that plasma treatment time and NOM presence influenced the adsorption capacity and rate constants of PFOA with the PSOM having emerged as the most fitting kinetic model. The Langmuir isotherm model indicates monolayer adsorption of PFOA on plasma-treated GAC, with higher maximum adsorption capacity while NOM is present. The Redlich–Peterson and Sips isotherm models indicated varying adsorption capacity and heterogeneity in the adsorption system. The Sips model was determined as the most fitting isotherm model. Furthermore, the favorable and spontaneous character of PFOA adsorption onto plasma-treated GAC was validated by thermodynamic analysis, with endothermic heat absorption during the process. Overall, this comprehensive investigation provides valuable insights into the adsorption characteristics of PFOA in the existence of NOM using GAC modified by DBD plasma.
... Sharp absorptions in the CH stretching region (3000-2800 cm −1 ) exhibit several new peaks and-coupled with the observation of the CH bending modes in the 1483-1434 cm −1 range-support the formation of alkyl groups during the irradiation exposure 42 . Sulfuric acid could be identified through the hydroxyl (OH) bending modes at 1241 cm −1 , the S=O symmetric stretching at 1166 cm −1 , and SO stretching modes at 961 cm −1 and 996 cm −1 43 . ...
... Sulfuric acid could be identified through the hydroxyl (OH) bending modes at 1241 cm −1 , the S=O symmetric stretching at 1166 cm −1 , and SO stretching modes at 961 cm −1 and 996 cm −1 43 . Most importantly, several peaks can be linked to functional groups associated with ASAs such as OH stretching modes at 2899 cm −1 and 2523-2588 cm −1 , the CH bending mode at 1464 cm −1 , the S=O stretching mode at 1210 cm −1 , the SOH bending at 1119 cm −1 , CH rocking at 996 cm −1 , and the C-S stretching at 724 cm −1 (medium dose) and 786 cm −1 (high dose) [42][43][44][45] . Therefore, these data provide compelling evidence that functional groups related to ASAs originate during the radiation exposure at 10 K. ...
For the last century, the source of sulfur in Earth’s very first organisms has remained a fundamental, unsolved enigma. While sulfates and their organic derivatives with sulfur in the S(+VI) oxidation state represent core nutrients in contemporary biochemistry, the limited bioavailability of sulfates during Earth’s early Archean period proposed that more soluble S(+IV) compounds served as the initial source of sulfur for the first terrestrial microorganisms. Here, we reveal via laboratory simulation experiments that the three simplest alkylsulfonic acids—water soluble organic S(+IV) compounds—can be efficiently produced in interstellar, sulfur-doped ices through interaction with galactic cosmic rays. This discovery opens a previously elusive path into the synthesis of vital astrobiological significance and untangles fundamental mechanisms of a facile preparation of sulfur-containing, biorelevant organics in extraterrestrial ices; these molecules can be eventually incorporated into comets and asteroids before their delivery and detection on Earth such as in the Murchison, Tagish Lake, and Allende meteorites along with the carbonaceous asteroid Ryugu.
... The -CF2 bands of pristine PTFE fade after etching or disappear (Figure 4d), as also observed by Raman spectroscopy. These bands can be related to the monofluorinated aliphatic group, -CH2-alkane, vinyl CH stretching, substituted alkyne -CC-H stretching (2137 cm −1 ), or, probably, reactions with THF (2550 cm −1 ) and N-H stretching [47]. The modification of Nafion leads to the presence of amino groups (3377 and 1572 cm −1 in the IR-ATR mode) on its surface without removing the sulfo group (727, 804, 972, and 1060 cm −1 , Figure 4b), making modified Nafion a zwitterionic membrane. ...
Polytetrafluoroethylene (PTFE) and, by extension, fluoropolymers are ubiquitous in science, life, and the environment as perfluoroalkyl pollutants (PFAS). In all cases, it is difficult to transform these materials due to their chemical inertness. Herein, we report a direct amination process of PTFE and some fluoropolymers such as polyvinylidene fluoride (PVDF) and Nafion by lithium alkylamide salts. Synthesizing these reactants extemporaneously between lithium metal and an aliphatic primary di- or triamine that also serves as a solvent leads to the rapid nucleophilic substitution of fluoride by an alkylamide moiety when in contact with the fluoropolymer. Moreover, lithium alkylamides dissolved in suitable solvents other than amines can react with fluoropolymers. This highly efficient one-pot process opens the way for further surface or bulk modification if needed, providing an easy, inexpensive, and fast experiment protocol on large scales.
... It is exceedingly challenging to identify C-N vibrations because of the blending of several bands. The range 1382-1266 cm −1 has been classified as the C-N stretching absorption by Socrates 26 . In this study, the C-N stretching mode is assigned at 1264 cm −1 in IR and 1250 cm −1 in Raman, which are supported by its PED (80%).The C-C and C-N in-plane bending vibrations are found as medium strong band at 786 cm −1 in FTIR and veryweak band at 865 cm −1 in the FT-Raman spectrum, respectively. ...
In this study, the FTIR and FT-Raman spectroscopies have been used to analyze the vibrational spectral characteristics of 3-chlorobenzamide (3CBA). Density functional theory (DFT) with B3LYP method has been used for theoretical computations, a number of solvents and diffuse functions (6-311+G(d,p) and 6-311++G(d,p)) have been used. The determined vibrational frequencies and structural parameters have been examined and compared with the experimental data. To clarify the electronic characteristics of the molecule, computations have been made using the frontier molecular orbital (FMO), molecular electrostatic potential (MEP), Fukui function and Mulliken analysis. The theoretical UV-Vis spectral study using various solvents (methanol and ethanol) has been made using time-dependent DFT computations. Molecular orbital contributions are investigated by densities of states (DOS) spectrum. The NMR chemical shifts for 1 H and 13 C have been computed using the gauge-independent atomic orbital technique. From the docking analysis of the molecule, the ovarian cancer inhibitors (human Matrix metalloproteinase-2) showed the binding affinity of-6.5 and-6.4 kcal/mol, and breast cancer inhibitors (human progesterone and allosteric inhibitor) showed the binding affinity of-6.0 and-5.7 kcal/mol, which are comparable with the binding affinity of standard drugs. To reveal the drug similarity, ADMET prediction has been utilized. Thus, the molecule's computational and biological properties show that it is a promising therapeutic candidate for the treatment of both ovarian and breast cancers.
... The various aspects of the spectrum and the peak assignments of the different compounds are used in the analysis of the FT-IR spectra of lipopeptides. These are useful in identifying the functional groups and the chemical properties of the compounds (Kong & Yu, 2007;Socrates, 2004). A typical FTIR system consists of a source, an interferometer, a detector, a computer, an amplifier, and a sample compartment. ...
Lipopeptides are a class of lipid–peptide‐conjugated compounds with differing structural features. This structural diversity is responsible for their diverse range of biological properties, including antimicrobial, antioxidant, and anti‐inflammatory activities. Lipopeptides have been attracting the attention of food scientists due to their potential as food additives and preservatives. This review provides a comprehensive overview of lipopeptides, their production, structural characteristics, and functional properties. First, the classes, chemical features, structure–activity relationships, and sources of lipopeptides are summarized. Then, the gene expression and biosynthesis of lipopeptides in microbial cell factories and strategies to optimize lipopeptide production are discussed. In addition, the main methods of purification and characterization of lipopeptides have been described. Finally, some biological activities of the lipopeptides, especially those relevant to food systems along with their mechanism of action, are critically examined.
... The C-C of the polymeric chain was responsible for the other strong vibrational peak that appeared about 906 cm −1 [43]. The vibration of C-H bonds produced signals at 1415 cm −1 in the spectrum. ...
The proton-conducting and methanol permeation behaviors of polymeric electrolyte membranes (PEMs), as well as the expensive nature of direct methanol fuel cell (DMFC) components, pose major concerns in DMFC performance and commercialization. As a result, this research aimed to develop low-cost polyelectrolyte membranes based on cross-linked poly(vinyl alcohol)/5-sulfosalicylic acid dehydrate (PVA/SSCA) composite. Chemical cross-linkers and modifiers offer the essential chemical and mechanical stability of the developed membranes for usage as polyelectrolyte membranes (PEMs). The manufactured composite proton exchange membranes provide several benefits, including significant thermal, chemical, and mechanical stability. The results revealed that extending the SSCA molar concentration increased IEC outcomes of the synthesized membranes, reaching an elevated level of (3.31 meq g⁻¹) compared to (0.91 meq g⁻¹) for the Nafion 117 membrane. The proton conductivity of a composite membrane (102 μm thick) measured by impedance spectroscopy was relatively (0.078 S cm⁻¹) and found comparable to other PVA-based composite membranes reported in the literature. Other key parameters, such as methanol permeability, were measured for constructed composite proton exchange membranes (2.52 × 10–7 cm² s⁻¹), which were much lower than Nafion 117 (3.39 × 10–6 cm² s⁻¹). The Fourier transform infrared (FT-IR), Raman scattering spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, elemental analysis, and thermal gravimetric analysis (TGA) were among the techniques used to characterize the synthesized membranes. These characterizations confirm the structural interaction between the membrane components’ crystalline nature, and no signs of phase separation or cracks were found; surface morphology and good membrane homogeneity, elemental analysis, and the membranes’ thermal stability (up to 290 °C). The membranes were also mechanically characterized using a universal testing machine (UTM), which revealed good mechanical stability. The findings demonstrate that a low-cost proton exchange membrane could potentially be synthesized for DMFC applications.
... The decrease in intensity at approximately 1750 cm −1 and increase in intensity at approximately 1720 cm −1 indicate the formation of acetic acid and were observed for DH aged modules [27], [28]. The measured spectra are also in accordance with the absorbance of pure acetic acid as they show a pronounced C=O peak from 1740 to 1700 cm −1 , which can also create a shoulder from 1710 to 1660 cm −1 [51]. The UV stabilizer consumption of the m_m_b position is even stronger than for the front encapsulant samples as seen in the Py-GCMS results. ...
In this work, a holistic approach to analyze solar module degradation is undertaken. The degradation kinetics of UV additives in the ethylene-vinyl acetate copolymer (EVA) encapsulant are derived using a quantification method. In addition, minimodules are analyzed after combined accelerated aging (UV irradiation at 85
$^\circ$
C and 60% relative humidity) at different positions. In this way, the local degradation reactions of the encapsulant are determined as a function of the prevailing stressors and additive consumption. These findings are correlated with the electrical characterization (
$I-V$
and electroluminescence measurements) to expand the understanding of module degradation. Performance losses are mainly due to a combination of hydrolysis and Norrish type II reactions of the encapsulant, as acetic acid is produced in both cases corroding the electrical contacts. Independent of the local stressor, the UV stabilizer shows first-order degradation kinetics, which is directly linked to the degradation of the encapsulant and, thus, indirectly to cell degradation. It is shown that the UV stabilizer consumption is an early precursor of module degradation and could be utilized to evaluate the remaining lifetime of a PV module.
... Vibrational peaks associated with NH 3 +, C-N, and C-H stretching modes predominantly manifest in the high wavenumber region (3500-1500 cm⁻¹) 27 . These N-H stretching wavenumbers experience a redshift due to the influence of intermolecular interactions, while their deformation modes undergo a blue shifted 28 . Typically, N-HꞏꞏꞏO intermolecular interactions are predicted to result in a broad peak within the infrared spectrum's range between 2100 and 1870 cm⁻¹. ...
The slow evaporation approach was used to produce and develop imidazolium 4-hydroxybenzoate (I4HB), a novel organic proton-transfer chemical substance. Through single-crystal X-ray diffraction, detailed study showed a monoclinic crystal structure with the centrosymmetric space group P21/n. Vibrational modes were investigated using FTIR and FT-Raman spectra. The chemical structure of the molecule was thoroughly validated using (1H and 13C) NMR analysis. UV-Vis-NIR absorption spectra were used to investigate electronic transitions. Thermal parameters such as a melting point of 215°C and breakdown phases were investigated using TG-DTA analysis. Third-order nonlinearity was also confirmed using Z-scan analysis.
... ν, stretching vibration; δ, deformation vibration; sym, symmetric vibration. a The interpretation of the bands is in accordance with Socrates[81], Cuenca et al.[82], and Kędzierska-Matysek et al.[83]. ...
There is a growing market for craft beverages with unique flavors. This study aimed to obtain a palate-pleasing mead derived from Pichia kudriavzevii 4A as a monoculture. Different culture media were evaluated to compare the fermentation kinetics and final products. The crucial factors in the medium were ~200 mg L−1 of yeast assimilable nitrogen and a pH of 3.5–5.0. A panel of judges favored the mead derived from Pichia kudriavzevii 4A (fermented in a medium with honey initially at 23 °Bx) over a commercial sample produced from Saccharomyces cerevisiae, considering its appearance, fruity and floral flavors (provided by esters, aldehydes, and higher alcohols), and balance between sweetness (given by the 82.91 g L−1 of residual sugars) and alcohol. The present mead had an 8.57% v/v ethanol concentration, was elaborated in 28 days, and reached a maximum biomass growth (2.40 g L−1) on the same fermentation day (6) that the minimum level of pH was reached. The biomass growth yield peaked at 24 and 48 h (~0.049 g g−1), while the ethanol yield peaked at 24 h (1.525 ± 0.332 g g−1), in both cases declining thereafter. The Gompertz model adequately describes the kinetics of sugar consumption and the generation of yeast biomass and ethanol. Pathogenic microorganisms, methanol, lead, and arsenic were absent in the mead. Thus, Pichia kudriavzevii 4A produced a safe and quality mead with probable consumer acceptance.
... 52 The presence of nitrate anions was confirmed with the characteristic Raman peak located at 1046 cm −1 assigned to the ν 1 (NO 3 ) symmetric stretching vibration (Fig. 4a). 56 Furthermore, two shoulders located on the lower frequency side of the uranyl peak (∼817 and 804 cm −1 ) and a weak Raman peak at 704 cm −1 may be assigned to the ν 2 ONO and ν 4 (NO 3 ) bending modes, respectively. ...
Although uranium oxide hydrate (UOH) minerals and synthetic phases have been extensively studied, the role of ammonium ions in the formation of UOH materials is not well understood. In this work, the stabilization of a synthetic UOH phase with ammonium ions and the inclusion of ammonium nitrate were investigated using a range of structural and spectroscopic techniques. Compound (NH4)2(NO3)[(UO2)3O2(OH)3] (U-N1) crystallises in the orthorhombic Pmn21 space group, having a layered structure with typical α-U3O8 type layers and interlayer (NH4)+ cations as well as (NO3)− anions. The presence of uranyl, (NH4)+ cations and (NO3)− anions were further confirmed with a combination of FTIR and Raman spectroscopies through characteristic vibrational modes. The roles of the (NH4)+ cations for charge compensation and facilitating the inclusion of (NO3)− anions via hydrogen bonding were revealed and discussed. The findings have implications for uranium geochemistry, reprocessing of spent nuclear fuel and possible spent nuclear fuel alteration pathways under geological disposal.
... IR spectra of the precursor of the FHU100N sample are shown in Fig. 6. The bands were identified in accordance with the data presented in the literature (Chen et al., 2020;Huang et al., 2015;Mamaní et al., 2019;Mariana et al., 2021;Renita et al., 2021;Socrates, 2001;Wibawa et al., 2020;Yan et al., 2020). time. ...
A number of new micro-mesoporous carbon materials (FHU100N, FHU100K, FHU70N30K, FHU50N50K and FHU20N80K) based on a mixture of furfural, hydroquinone, and urotropine have been synthesized by the alkaline activation method using a combination of activating agents (KOH and NaOH). The influence of the porous structure of the synthesized adsorbents has been studied with particular attention to the pore size distribution, in particular, to the pore volume in which MG can be adsorbed most efficiently from aqueous solutions. Subsequently, among the tested carbons, the FHU100N has excellent porosity (total pore volume, micropore volume and mesopore volume: 1.136, 0.632 and 0.504 cm³ /g, respectively) with the highest surface area (2575 m² /g). The adsorption capacity of FHU100N (1300 mg/g) for malachite green (MG) was superior to other micro mesoporous carbons (500–918 mg/g). The results obtained showed that the key contribution to the adsorption of the MG dye is made by pores ranging in size from 2 to 3.5 nm. The FHU100N adsorbent, which showed the highest MG adsorption activity, was characterized by nitrogen adsorption, FTIR, Raman spectroscopy, and XRD techniques. To understand the adsorption mechanisms on the obtained material, detailed mathematical analysis of experimental sorption data was carried out using the existing kinetic (pseudo-first order and pseudo-second order) models and diffusion (Weber-Morris and Boyd) models, along with adsorption equilibrium isotherms (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich).
Graphical Abstract
... Peak assignment from the 1 H-NMR spectra of gallic acid solutions against sugarcane enzymatic crude extracts over timeThe group frequencies are also based onSocrates' (2004) book as a suggestion of functional groups and their vibrations model system involving gallic acid and sugarcane oxidase enzyme extract. Since we know that oxidative enzymes play an important role in the darkening of sugarcane juice, the search for technological solutions is a way to reduce the coloration in both the juice and the produced sugar. ...
Although sugarcane is economically important, few studies have been reported on enzymatic browning mechanisms in sugarcane juice. Using advanced analytical techniques, a model study with gallic acid and sugarcane oxidases was carried out to elucidate the mechanisms for colored compound formation in sugarcane juice. Optimized reactions were determined as a combination of temperature at 50 °C and pH 5. The conversion rate of gallic acid by oxidases was 0.21 mg L⁻¹ h⁻¹. Even though the gallic acid conversion (an important phenolic acid in sugarcane) to o-quinones has been demonstrated, we reported that the end products of enzymatic browning reactions are nitrogenous compounds. Aspartate took part in the condensation reactions mimicking similar reactions among gallic acid and amino acids.
Graphical Abstract
... PPGDGE-PEI (Figure 6c) contain almost all vibrations characteristic of individual substances BADGE, PPGDGE and PEI. A key indicator of the opening of the epoxide ring is a sharp decrease in the intensity of signals 908 cm −1 for BADGE and 834 cm −1 for PPGDGE copolymers referred to characteristic valence vibrations of the C-O epoxide group [20,37,38]. (Figure 6d) characteristic of PEI and PPGDGE, respectively, change monotonously. ...
Limitations in existing anion exchange membranes deter their use in the efficient treatment of industrial wastewater effluent. This work presents an approach to fabricating novel anion-conducting membranes using epoxy resin monomers like hydrophobic or hydrophilic diglycidyl ether and quaternized polyethyleneimine (PEI). Manipulating the diglycidyl ether nature, the quantitative composition of the copolymer and the conditions of quaternization allows control of the physicochemical properties of the membranes, including water uptake (20.0–330%), ion exchange capacity (1.5–3.7 mmol/g), ionic conductivity (0.2–17 mS/cm in the Cl form at 20 °C), potentiostatic transport numbers (75–97%), as well as mechanical properties. A relationship was established between copolymer structure and conductivity/selectivity trade-off. The higher the quaternized polyethyleneimine, diluent fraction, and hydrophilicity of diglycidyl ether, the higher the conductivity and the lower the permselectivity. Hydrophobic diglycidyl ether gives a much better conductivity/selectivity ratio since it provides a lower degree of hydration than hydrophilic diglycidyl ether. Different mesh and non-woven reinforcing materials were also examined. The developed membranes demonstrate good stability in both neutral and acidic environments, and their benchmark characteristics in laboratory electrodialysis cells and batch-mode dialysis experiments are similar to or superior to, commercial membranes such as Neosepta© AMX, FujiFilm© Type1, and Fumasep FAD-PET.
... The bands at 692 cm −1 and 583 cm −1 are related rocking vibration of groups R-SiH 3 and to the asymmetric stretching of the Si-C bond of groups silanes R 2 SiPh 2 , respectively. Finally, the bands observed at 425 cm −1 correspond to the common stretching of Si-Si bonds [41]. ...
The combination of silica nanoparticles with fluorescent molecularly imprinted polymers (Si-FMIPs) prepared by a one-pot sol-gel synthesis method to act as chemical sensors for the selective and sensitive determination of captopril is described. Several analytical parameters were optimized, including reagent ratio, solvent, concentration of Si-FMIP solutions, and contact time. Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and the ninhydrin assay were used for characterization. The selectivity was evaluated against molecules belonging to other drug classes, such as fluoroquinolones, nonacid nonopioids, benzothiadiazine, alpha amino acids, and nitroimidazoles. Under optimized conditions, the Si-FMIP-based sensor exhibited a working range of 1–15 µM, with a limit of detection (LOD) of 0.7 µM, repeatability of 6.4% (n = 10), and suitable recovery values at three concentration levels (98.5% (1.5 µM), 99.9% (3.5 µM), and 99.2% (7.5 µM)) for wastewater samples. The sensor provided a working range of 0.5–15 µM for synthetic urine samples, with an LOD of 0.4 µM and a repeatability of 7.4% (n = 10) and recovery values of 93.7%, 92.9%, and 98.0% for 1.0 µM, 3.5 µM, and 10 µM, respectively. In conclusion, our single-vessel synthesis approach for Si-FMIPs proved to be highly effective for the selective determination of captopril in wastewater and synthetic urine samples.
Graphical abstract
... cm − 1 ν(C --O), ~1640 cm − 1 (ν (C --C)and/or tertiary amide and/or δ(H 2 O)), ~1450 cm − 1 δ(CH 2 , CH 3 ), ~1280 cm − 1 , ~1250 cm − 1 , 1160 cm − 1 , and 1076 cm − 1 ~ 1024 cm − 1 (ν(C-O) of ester and ether)[25,26]. ...
... In fact, in sodium alginate, as mentioned before, it is possible to observe only one broad band from 2998 to 3667 related to the presence of free water, as well as intermolecular and intramolecular hydrogen bonds that also affected the CH peaks identification. Differently, in all crosslinked samples it is possible to observe both the band in the range between 3100 and 3600 due to the presence of free hydroxyl groups, and a new peak around 2847 probably due to the implication of OH groups in the chelation complex (Socrates, 2004). Moreover, Fuks et al. suggested the role of hydrate ionic radius as a variable that influences the type of complexation, evidenced by the differences in the chelated OH peaks intensity detected in our samples (Fuks, Filipiuk & Majdan, 2006). ...
... The stretching of the C-O group is associated to two peaks at 1268 cm −1 and 1221 cm −1 while the stretching of the C = O group results in an intense signal at 1713 cm −1 . Due to the increased number of C-H bonds present in PPeF with respect to PLA, the signals associated to the methylene groups are intensified: the peaks at 2954 cm −1 and 2860 cm −1 correspond respectively to the asymmetric ( ν as ) and symmetric ( ν s ) stretching, while the signals at 1469 cm −1 and 1300 cm −1 are related to the in-phase rocking and twisting [51] . ...
... This assumption can be based on data from Zhuravlev [62] [57][58][59]63 In summary, the ATR spectra of the dye-MSN@TiO 2 particles show silica-related, dye-related, titaniarelated vibrations as well as additionally silica-titania bonds, supporting the observation that dyeencapsulation by titania coating was successful. [64] , b Zu, et al. [65] , c Islam, et al. [61] , d Hema, et al. [63] , e Pérez, et al. [66] . ...
Mesoporous silica nanoparticles hosting guest molecules are a versatile tool with applications in various fields such as life and environmental sciences. Current commonly applied pore blocking strategies are not universally applicable and are often not robust enough to withstand harsh ambient conditions (e.g. geothermal). In this work, a titania layer is utilized as a robust pore blocker, with a test-case where it is used for the encapsulation of fluorescent dyes. The layer is formed by a hydrolysis process of a titania precursor in an adapted microemulsion system and demonstrates effective protection of both the dye payload and the silica core from disintegration under otherwise damaging external conditions. The produced dye-MSN@TiO2 particles are characterized by means of electron microscopy, elemental mapping, ζ-potential, X-ray diffraction (XRD), nitrogen adsorption, Thermogravimetric analysis (TGA), fluorescence and absorbance spectroscopy and Fourier Transform Infrared Spectroscopy – Total Attenuated Reflectance (FT-IR ATR). Finally, the performance of the titania-encapsulated MSNs is demonstrated in long-term aqueous stability and in flow-through experiments, where owing to improved dispersion encapsulated dye results in improved flow properties compared to free dye properties. This behavior exemplifies the potential advantage of carrier-borne marker molecules over free dye molecules in applications where accessibility or targeting are a factor, thus this encapsulation method increases the variety of fields of application.
... The broad band decreased and appeared at 3411 cm À1 after MOF formation due to the OH stretching mode of the coordinated water molecule. 56,57 The bands reported at 1690 cm À1 and 1280 cm À1 were associated with the uncoordinated (n(CQO) and n(C-O)) in the BDC, respectively. [58][59][60][61][62] After coordination, these absorption bands were replaced by the n(COO À ) of carboxylates, and their absorption bands were shifted to n as (COO À ) at ca. 1598 and 1533 cm À1 , and n s (COO À ) at ca. 1462 and 1410 cm À1 . ...
A zinc-based organic framework was synthesized using a fast, economical, and environmentally friendly sonochemical method. It consisted of a zinc central metal ion coordinated to a 1,3-benzene dicarboxylate linker (BDC). Several techniques have been employed to determine the exact chemical structure of the synthesized metal–organic framework. The X-ray diffraction pattern (XRD) matches the theoretical pattern of the polymeric [Zn(BDC)(H2O)]n structure. The suggested structure of Zn-MOF was supported by FTIR, ¹H NMR and ¹³C NMR studies. The morphological structures of Zn-MOF particles and the modified electrode GC/Zn-MOF before and after paracetamol (PA) oxidation were characterized using SEM. Also, the modified electrode composition was analyzed using energy-dispersive X-ray spectroscopy and mapping techniques. The modified GC/Zn-MOF electrode exhibited a detection limit (LOD) of 0.104 μM with a linear detection range of 1–50 μM PA in a phosphate buffer solution (PBS) using a differential pulse technique. Additionally, the modified Zn-MOF electrode exhibited anti-interference capability in the presence of different species. The negative adsorption energy predicted the spontaneity of the PA adsorption on the GC/Zn-MOF electrode surface. The modified GC/Zn-MOF electrode is simple, reliable, and practical, with promising potential for application as a PA sensor.
... The Raman spectra of DMF, PVdF-HFP film, binary liquid, and binary ionogel-100 film are shown in Figure 2. The characteristic peaks of DMF at 657 and 866 cm À 1 ascribed to the O=CÀ N in-plane bending and CÀ N stretching, [36,37] respectively, are totally absent from the spectra of PVdF-HFP and binary ionogel-100 (Figure 2a), proving a very effective elimination of DMF from the two films. By deconvoluting the region ranging from 777 to 680 cm À 1 (Figure 2b), it can be seen that the Raman spectrum of the binary liquid is composed of three peaks corresponding to the symmetric stretching mode (A 1g ) of the [BF 4 À ] anion at 764 cm À 1 , SNS scissoring of the [FSI À ] anion at 725 cm À 1 and ring in-plane asymmetric bending of the [EMIm + ] cation at 702 cm À 1 . ...
Over the last years, solid‐state electrolytes made of an ionic liquid (IL) confined in a solid (inorganic or polymer) matrix, also known as ionogels, have been proposed to solve the leakage problems occurring at high temperatures in classical electrical double‐layer capacitors (EDLCs) with an organic electrolyte, and thereof improve the safety. However, making ionogel‐based EDLCs perform with reasonable power at low temperature is still a major challenge due to the high melting point of the confined IL. To overcome these limitations, the present contribution discloses ionogel films prepared in a totally oxygen/moisture‐free atmosphere by encapsulating 70 wt % of an equimolar mixture of 1‐ethyl‐3‐methylimidazolium bis(fluorosulfonyl)imide and 1‐ethyl‐3‐methylimidazolium tetrafluoroborate – [EMIm][BF4]0.5[FSI]0.5 – into a poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) network. The further called “binary ionogel” films demonstrated a high flexibility and a good ionic conductivity of 5.8 mS cm⁻¹ at 20 °C. Contrary to the ionogels prepared from either [EMIm][FSI] or [EMIm][BF4], displaying melting at Tm=−16 °C and −7 °C, respectively, the crystallization of confined [EMIm][BF4]0.5[FSI]0.5 is quenched in the binary ionogel, which shows only a glass transition at −101 °C. This quenching enables an increased ionicity and ionic diffusion at the interface with the PVdF host network, leading the binary ionogel membrane to display higher ionic conductivity below −20 °C than the parent binary [EMIm][BF4]0.5[FSI]0.5 liquid. Laminate EDLCs were built with a 100 μm thick binary ionogel separator and electrodes made from a hierarchical micro‐/mesoporous MgO‐templated carbon containing a reasonable proportion of mesopores to enhance the mass transport of ions, especially at low temperature where the ionic diffusion noticeably decreases. The EDLCs operated up to 3.0 V with ideal EDL characteristics from −40 °C to room temperature. Their output specific energy under a discharge power of 1 kW kg⁻¹ is ca. 4 times larger than with a cell implementing the same carbon electrodes together with the binary [EMIm][BF4]0.5[FSI]0.5 liquid. Hence, this binary ionogel electrolyte concept paves the road for developing safe and flexible solid‐state energy storage devices operating at subambient temperatures in extreme environments.
... 1393, 1168.38 and 1103.17 cm -1 were assigned to the stretching vibration of -C-N triple bond of nitriles, N-C=O amide bond of proteins, nitrate ion, -C-O-Cof esters or ethers, respectively (Socrates, 1980). After reaction with 1 mM silver nitrate solution, there was a shift in the following peaks: 2081.34 to 2099.45 cm -1 , 1639.35 to 1617.61 cm -1 , 1393 to 1382.12 cm -1 , 1103.17 to 1059.70 cm -1 , and the disappearance of the peak at 1168.38 cm -1 indicating that nitrile, amide, nitrate and carboxyl groups on the surface of the AEOG may be participating in the synthesis of nanoparticles. ...
Ocimum gratissimum leaves were used in the synthesis of silver nanoparticles (AgNps) that were non-toxic and also possessed antimicrobial properties against clinically isolated pathogenic strains. Some bioactive agents in the aqueous extract of Ocimum gratissimum leaves (AEOgL) were identified. AgNp synthesis was carried out by incubating the AEOgL and 1 mM AgNO3. The brownish colour obtained upon reduction of silver by the AEOgL was observed. The phytochemicals present are tannins, glycosides, sterols, phenols, alkaloid and terpenoids. There was the presence of a surface plasmon resonance from the UV-visible scan. The synthesized silver nanoparticles were characterized by UV-visible spectrophotometry, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy/Energy Dispersive Analysis (SEM/EDX) and X-ray diffraction analysis. The SEM/EDX analysis indicated that the morphology of the nanoparticles is of a uniform structure and the size of the AgNp was 20 nm. The AgNps showed excellent antimicrobial activity against clinically isolated multi-drug resistant human pathogens used such as Escherichia coli and Staphylococcus aureus. For most biomarkers in the blood biochemistry analysis, there was no significant difference (p<0.05) between the control and treated groups except for alkaline phosphatase. It can concluded from this study that AgNps synthesized from aqueous extract of Ocimum gratissimum had antimicrobial properties and is also non-toxic at the dosage used.
... FT-IR ATR spectroscopy is commonly used to identify chemical bonds based on their unique bending and stretching vibrational characteristics in the infrared wavelength region. Important wavenumbers for silica nanoparticles are 1100 -1000 cm -1 for asymmetric Si-O-Si (siloxane) stretching, 802 cm -1 for symmetric siloxane wagging, 455 cm -1 for siloxane bending vibration, and 970 cm -1 for Si-OH (silanol) stretching (Socrates, 2004, Widjonarko et al., 2014. Other important information can be identified in the region of 3700 -3200 cm -1 , vibrations can be assigned to stretching of adsorbed OH molecules (Widjonarko et al., 2014). ...
Accurate knowledge of reservoir geometry and flow paths are critical parameters for successful geothermal operations. They are essential for evaluating the long-term behavior and sustainability of geothermal reservoirs. Conventional hydraulic testing and tracer tests are often inconclusive or provide limited information due to complex and challenging reservoir conditions (multiple well systems, complex reservoir geometry, and fracture network, etc.). Recently, a new class of tracer techniques has emerged in order to overcome the major drawbacks of molecular tracers: nanoparticle-based tracers. The main advantages of nanoparticle tracers compared to molecular tracers are their tunable properties and modular structure. Functional and smart nanoparticle tracers such as the threshold-triggered temperature nanotracer enabled the simultaneous evaluation of multiple reservoir conditions (flow paths, temperature distribution, etc.) and created an entirely new field of research. As new areas of research often require detailed insights into fundamental processes, there are still open questions about the interactions between particles, fluids, and rock minerals and their performance in complex geothermal environments. As an example, the application of embedded or surface-bound tracing features (e.g., fluorescent molecules, DNA, etc.) within or on a silica matrix prevents the tracing function from being affected by the environment (e.g., pH changes, salinity effects, redox sensitivity). Although silica has low hydro(thermal) stability and loses its protective function at high temperatures or long-term applications, nanoscience offers a comprehensive set of tools to design and protect the silica matrix. Another advantage is the possibility of surface modifications, which can help to achieve minimum sorption and retention by adapting the ζ-potential of the nanoparticles. In this study, we address recent advances in increasing long-term stability, improving hydrothermal stability of silica nanoparticles, sorption control. Furthermore, we present strategies for the development and functionalization of nanoparticle-based tracers.
... The most characteristic feature of carboxylic group is a single band observed usually in the range 1690-1655 cm −1 region [30,31] and this band is due to the C O stretching vibration. The band appearing at 1685 cm −1 as a very strong band in FT-IR is assigned to C O stretching vibration. ...
The vibrational spectra of 2-bromobenzoic acid (2BBA) have been experimentally recorded (FT-IR and FT-Raman) and compared with the harmonic vibrational frequencies calculated at HF and B3LYP level of theories using 6-311+G(d,p) basis set with appropriate scaling factors. The XRD geometrical parameters show satisfactory agreement with the theoretical prediction at Hartree-Fock and B3LYP levels. The scaled vibrational frequencies at B3LYP/6-311+G(d,p) seem to coincide with the experimentally observed values with acceptable deviations. The theoretical spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra.
... The epoxy resin fingerprint is depicted in Figure 7, with the Raman shift corresponding to epoxide vibration between 1280 cm −1 and 1230 cm −1 . In this study, the measurement of epoxide vibration was recorded at 1247 cm −1 [70]. The Raman peak at 826 cm −1 is attributed to -CH wagging vibrations, while resin backbone vibrations are evident at 1141 cm −1 , 1205 cm −1 , and 1454 cm −1 [71]. ...
This paper presents an experimental investigation of nanocomposites composed of three ratios of epoxy/graphene nanoplatelets (GNPs) by weight. The 0.1, 0.2, and 0.3 wt.% specimens were carefully manufactured, and their mechanical and thermal conductivity properties were examined. The tensile strength and modulus of epoxy/GNPs were enhanced by the large surface area of graphene nanoplatelets, causing crack deflection that created new fracture fronts and friction because of the rough fracture surface. However, the compressive strength was gradually reduced as GNP loading percentages increased. This was probably due to severe plastic yielding on the epoxy, leading to catastrophic axial splitting caused by premature fractures. Furthermore, the highest thermal conductivity was 0.1283 W/m-K, representing a 20.92% improvement over neat epoxy (0.1061 W/m-K) when 0.3 wt.% GNPs were added to the epoxy. This was because of efficient heat propagation in the GNPs due to electron movement through percolative paths. The tensile failure mode in epoxy/GNP nanocomposites showed a few deflected and bifurcated rough cracks and brittle, dimple-like fractures. Contrarily, compressive failure mode in GNP-added epoxy showed plastic flexural buckling and brittle large-axial splitting. The epoxy/GNP nanocomposites were considered a damage-tolerant material.
The investigated Macropanax dispermus (Blume) Kuntze (Araliaceae) extracts exhibited significant activity against hyperglycemia and castor oil-induced diarrhea and might contribute to the formulation of alternative medicinal agents to treat diabetes and diarrhea. In addition, MDMS was proved to be an effective anthelmintic agent. Please cite this paper as: Afrin SR, Islam MR, Didari SS, Jannat SW, Nisat UT, Hossain MK. Investigation of hypoglycemic and antidiarrheal activity on mice model and in vitro anthelmintic study of Macropanax dispermus (Blume) Kuntze (Araliaceae): a promising ethnomedicinal plant. Introduction: Macropanax dispermus is an ethnomedicinal plant, which has been shown to have pharmacological effects against inflammation. Inflammation is also associated with diabetic-related complications. In addition, the indigenous people used this plant to cure numerous digestive system disorders. These ethnomedicinal uses have inspired the current research to focus on determining the biological potential of the crude methanol extract of its leaves (MDML) and stem barks (MDMS) against morbid diseases such as diarrhea, helminthiasis, and diabetes mellitus related to hyperglycemia. This study also identified the functional groups present in MDML which could correlate the presence of different phytochemicals responsible for biological activities. Methods: The hypoglycemic activity and antidiarrheal tests were done on Swiss albino mice through an oral glucose tolerance test (OGTT) and castor-oil-induced diarrhea, respectively. The anthelmintic test was done in vitro on Pheretima posthuma. The functional groups were identified by using Fourier-transform infrared (FTIR) spectroscopy. Results: Here, MDML at 400 mg/kg exhibited a significant (P<0.05) hypoglycemic activity as well as decreased diarrheal drops significantly (P<0.001) when compared to the control group. Additionally, MDMS showed a concentration-dependent significant effect as a prospective anthelmintic agent. The FTIR spectra demonstrated the presence of different functional groups, which might contribute to the presence of flavonoids, saponins, terpenoids, and other related compounds. Conclusion: The present research demonstrated that MDML and MDMS might be effective interventions for treating hyperglycemia, diarrhea, and helminthiasis.
Organic–inorganic hybrid nanocomposites (OIHN), with tailored surface chemistry, offer ultra-sensitive architecture capable of detecting ultra-low concentrations of target analytes with precision. In the present work, a novel nano-biosensor was fabricated, acquainting dynamic synergy of reduced graphene oxide (rGO) decorated hexagonal boron nitride nanosheets (hBNNS) for detection of carcinoembryonic antigen (CEA). Extensive spectroscopic and microscopic analyses confirmed the successful hydrothermal synthesis of cross-linked rGO-hBNNS nanocomposite. Uniform micro-electrodes of rGO-hBNNS onto pre-hydrolyzed ITO were obtained via electrophoretic deposition (EPD) technique at low DC potential (15 V). Optimization of antibody incubation time, pH of supporting electrolyte, and immunoelectrode preparation was thoroughly investigated to enhance nano-biosensing efficacy. rGO-modified hBNNS demonstrated 29% boost in electrochemical performance over bare hBNNS, signifying remarkable electro-catalytic activity of nano-biosensor. The presence of multifunctional groups on the interface facilitated stable crosslinking chemistry, increased immobilization density, and enabled site-specific anchoring of Anti-CEA, resulting in improved binding affinity. The nano-biosensor demonstrated a remarkably low limit of detection of 5.47 pg/mL (R2 = 0.99963), indicating exceptional sensitivity and accuracy in detecting CEA concentrations from 0 to 50 ng/mL. The clinical evaluation confirmed its exceptional shelf life, minimal cross-reactivity, and robust recovery rates in human serum samples, thereby unraveling the potential for early, highly sensitive, and reliable CEA detection.
The search for new effective drugs in the treatment of neoplasm remains relevant even today, since the adaptation of transformed cells to the action of classical drugs contributes to the emergence of drug resistance. This applies to a number of classic chemotherapy drugs of the platinum series, in particular cisplatin. In this work, we describe the effect of novel analogs of cisplatin on HepG2 cells and on the key enzyme of antioxidant protection system gammaglutamyltranspeptidase, which plays an important role in the acquisition of drug resistance to anticancer drugs by tumor cells. New mononuclear iodide n,π-chelate complexes of Pt(II) with substituted thioureas N-allylmorpholine-4-carbothioamide or 3-allyl-1,1-diethylthiourea were obtained as analogs of cisplatin. All compounds were investigated by UV-Vis, IR, and 1H/13С NMR spectra. Complex I was described by single-crystal X-ray diffraction study. Also, the effect of these analogs on alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, which are marker enzymes of liver cells, release of which into the blood indicates liver pathologies, was investigated. All studies were carried out in comparison with chloride n,π-chelate complexes of platinum obtained earlier (however, the effect of these chloride analogs of platinum on enzymes of the hepatobiliary system was investigated for the first time in this work). The results have shown that the studied compounds are better cytostatics/cytotoxics than cisplatin both according to IC50 and apoptosis level of HepG2 cells. It is established that, for the most part, effect of the studied complexes is reduced to a decrease in the degree of malignancy of cells of hepatocyte lines and the activity of LDH and GHT, as well as a decrease in consumed glucose. Keywords: alanine aminotransferase, aspartate aminotransferase, gammaglutamyltranspeptidase, lactate dehydrogenase, NMR spectroscopy, n‚π-chelates, thioureas
The adulteration of sheep butter with cow butter and margarine is a significant challenge in the food industry, impacting product authenticity and consumer confidence. In this research article, a comprehensive and accurate approach is proposed for detecting sheep butter adulteration by employing Raman spectroscopy in conjunction with the combined method of DD-SIMCA and PLS-DA.
Initially, Raman spectroscopy employed to collect spectral data from pure butter and margarine samples, enabling the modeling of target objects by DD-SIMCA to exclude adulterated samples. Subsequently, PLS-DA was utilized for the discrimination of sample classes.
Raman spectroscopy, combined with the classification and discrimination strategy, is a powerful tool for quickly and non-destructively detecting sheep butter adulteration, ensuring food quality control. The combined strategy successfully discriminated between pure samples, achieving high performances based on the figures of merit (sensitivity: 77.78-100% and specificity: 88.23-100%) for detecting and identifying the type of adulteration in sheep butter. These outcomes underscore the efficacy of the proposed approach in not only detecting but also identifying the specific type of adulteration present in sheep butter, thereby addressing a critical need in the food industry. This research contributes significantly to advancing the field of food quality assurance and holds great implications for support consumer confidence in product authenticity.
Transparent materials in contact with harmful environments such as sandstorms are exposed to surface damage. Transparent MgAl2O4 spinel used as protective window, lens or laser exit port, among others, is one of the materials affected by natural aggressions. The impact of sand particles can cause significant defects on the exposed surface, thus affecting its optical and mechanical behavior. The aim of this work is to improve the surface state of a spinel damaged surface by the deposition of a thin layer of SiO2-ZrO2. For this purpose, spinel samples obtained from different commercial powders sintered by Spark Plasma Sintering were sandblasted and further coated with a SiO2-ZrO2 thin layer. The coating was successfully synthesized by the sol/gel method, deposited on the sandblasted samples and then treated at 900 °C, reaching a final thickness of 250 nm. The results indicated that sandblasting significantly affects the surface of the spinel samples as well as the optical transmission, confirmed by UV-visible spectroscopy and profilometry tests. However, the deposition of a SiO2-ZrO2 coating modifies the UV-visible response. Thus, the optical transmission of the S25CRX12 sample presents the best transmission values of 81%, followed by the S25CRX14 sample then the S30CR sample at 550 nm wavelength. An important difference was observed between sandblasted samples and coated samples at low and high wavelengths. At low wavelengths (around 200 nm), sandblasting tends to improve significantly the transmission of spinel samples, which exhibit a low transmission in the pristine state. This phenomenon can be attributed to the healing of small superficial defects responsible for the degradation of transmission such as pores or flaws. When the initial transmission at 200 nm is high, the sandblasting worsens the transmission. Sandblasting reduces slightly the transmission values for long wavelengths due to the formation of large superficial defects like chipping by creation and propagation of lateral cracks. The coating of the sandblasted samples exhibits some healing of defects induced by sandblasting. The deposition of the SiO2-ZrO2 layer induces a clear increase in the optical transmission values, sometimes exceeding the initial values of the transmission in the pristine state.
Etanol içeren alkollü ve gazlı içeceklerin fazla miktarda etanol tüketimi, muhakeme yeteneğinin bozulmasına, bilinç kaybına, komaya ve hatta ölüme neden olmaktadır. Çalışmada, Türkiye’ye özgü bir alkollü içecek olan Boğma Rakı’daki etanolün Raman Spektroskopisi ve Temel Bileşenler Analizi (PCA) metodu ile kalitatif analizi amaçlanmıştır. Farklı koşullarda üretimi yapıldığı bilinen Boğma Rakı numunelerinde (22 adet) bulunan etanole ait spesifik bantlar, Raman spektroskopisi kullanılarak incelendi. Elde edilen verilere PCA metodunun uygulanması için OriginPro 2022 programı kullanıldı. Çalışmada, 100-1600 cm-1 aralığında etanole ait en belirgin bandın 883 cm-1’de olduğu gözlendi. Numunelerin sınıflandırılması amacıyla kullanılan PCA metodu sonucunda iki tane PCs (Principal Components) değeri elde edildi. Toplam PC1 değeri %95.22 ve toplam PC2 değeri ise %4.64 olarak elde edildi ve bu değerlerin toplamının veri setinin toplam varyansının %99.86'sını oluşturduğu görüldü. Elde edilen PC1 ve PC2 değerlerinin numunelerin etanol ile ilgili olduğu saptandı. Alkollü içeceklerin Raman spektroskopisi incelenmesinin ve elde edilen verilere kemometrik metotların uygulanması, alkollü içeceklerde bulunan etanolün tespitinde etkili olduğu görüldü. Çalışmada, Raman spektroskopisinin PCA metodu ile kombinasyonunun kaçak veya yasal olmayan yollarla üretilen alkollü içeceklerdeki bileşenlerin kontrolünde tarama yöntemi olarak kullanılabileceği sonucuna varıldı.
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