Aurelio A. de los Reyes V

University of the Philippines | UPD · Institute of Mathematics

Tuberculosis (TB) is one of the top 10 causes of death globally and the leading cause of death by a single infectious pathogen. The World Health Organization (WHO) has declared the End TB Strategy, which targets a 90% reduction in the incidence rate by the year 2035 compared to the level in the year 2015. In this work, a TB model is considered to u...

Proteasome inhibition and oncolytic virotherapy are two emerging targeted cancer therapies. Bortezomib, a proteasome inhibitor, disrupts the degradation of proteins in the cell leading to accumulation of unfolded proteins inducing apoptosis. On the other hand, oncolytic virotherapy uses genetically modified oncolytic viruses (OV) to infect cancer c...

This work examines a cardiovascular-respiratory system model capable of describing its dynamic response to a constant workload. The heart rate and alveolar ventilations are considered fundamental controls of the system which represent the baroreceptor and chemoreceptor loops, respectively. Multi-method sensitivity analysis is performed to quantify...

In a tumour microenvironment, tumour-associated neutrophils could display two opposing differential phenotypes: anti-tumour (N1) and pro-tumour (N2) effector cells. Converting N2 to N1 neutrophils provides innovative therapies for cancer treatment. In this study, a mathematical model for N1-N2 dynamics describing the cancer survival and immune inhi...

Anovulation refers to a menstrual cycle characterized by the absence of ovulation. Exogenous hormones such as synthetic progesterone and estrogen have been used to attain this state to achieve contraception. However, large doses are associated with adverse effects such as increased risk for thrombosis and myocardial infarction. This study utilizes...

Background Sleep and circadian rhythm disruptions are common in patients with mood disorders. The intricate relationship between these disruptions and mood has been investigated, but their causal dynamics remain unknown. Methods We analysed data from 139 patients (76 female, mean age = 23.5 ± 3.64 years) with mood disorders who participated in a p...

Bortezomib and oncolytic virotherapy are two emerging targeted cancer therapies. Bortezomib, a proteasome inhibitor, disrupts protein degradation in cells, leading to the accumulation of unfolded proteins that induce apoptosis. On the other hand, virotherapy uses genetically modified oncolytic viruses (OVs) to infect cancer cells, trigger cell lysi...

COVID-19 has affected millions of people worldwide, causing illness and death, and disrupting daily life while imposing a significant social and economic burden. Vaccination is an important control measure that significantly reduces mortality if properly and efficiently distributed. In this work, an age-structured model of COVID-19 transmission, in...

Tuberculosis (TB) and human immunodeficiency virus (HIV) are the two major public health emergencies in the Philippines. The country is ranked fourth worldwide in TB incidence cases despite national efforts and initiatives to mitigate the disease. Concurrently, the Philippines has the fastest-growing HIV epidemic in Asia and the Pacific region. The...

The Coronavirus disease 2019 (COVID-19) has exposed many systemic vulnerabilities in many countries' health system, disaster preparedness, and adequate response capabilities. With the early lack of data and information about the virus and the many differing local-specific factors contributing to its transmission, managing its spread had been challe...

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2. Millions of people have fallen sick, and some have died due to this affliction that has spread across the globe. The current pandemic has disrupted normal day-to-day human life, causing a profound social and economic burden. Vacci...

Anovulation refers to a menstrual cycle characterized by the absence of ovulation. Exogenous hormones such as synthetic progesterone and estrogen have been used to attain this state to achieve contraception. However, large doses are associated with adverse effects such as increased risk for thrombosis and myocardial infarction. This study utilizes...

Schistosomiasis is a neglected tropical disease endemic in the Philippines, affecting 28 provinces in 12 regions. This parasitic disease is caused by Schistosoma japonicum , a zoonotic parasite that infects other mammalian hosts aside from humans. In this study, a mathematical model is developed to describe the transmission of schistosomiasis in Ag...

Chemical reaction networks (CRNs) are directed graphs with reactant or product complexes as vertices, and reactions as arcs. A CRN is weakly reversible if each of its connected components is strongly connected. Weakly reversible networks can be considered as the most important class of reaction networks. Now, the stoichiometric subspace of a networ...

Chemical reaction networks (CRNs) are directed graphs with reactant or product complexes as vertices, and reactions as arcs. A CRN is weakly reversible if each of its connected components is strongly connected. Weakly reversible networks can be considered as the most important class of reaction networks. Now, the stoichiometric subspace of a networ...

One important question that interests those who work in chemical reaction network theory (CRNT) is this: Does the system obtained from a reaction network admit a positive equilibrium and if it does, can there be more than one within a stoichiometric class? The higher deficiency algorithm (HDA) of Ji and Feinberg provided a method of determining the...

The human immunodeficiency virus (HIV) impairs a person's immune system against many infections and some types of cancer, leading to acquired immunodeficiency syndrome (AIDS), which is characterized by severe illnesses. The number of HIV infections in the Philippines has increased, more than doubled, within the last decade. This alarming HIV crisis...

One important question that interests those who work in chemical reaction network theory (CRNT) is this: Does the system obtained from a reaction network admit a positive equilibrium and if it does, can there be more than one within a stoichiometric class? The higher deficiency algorithm (HDA) of Ji and Feinberg provided a method of determining the...

Studies have been done using networks to represent the spread of infectious diseases in populations. For diseases with exposed individuals corresponding to a latent period, an SEIR model is formulated using an edge-based approach described by a probability generating function. The basic reproduction number is computed using the next generation matr...

This paper presents a computational solution to the multistationarity problem for any power-law kinetic system, i.e., to determine if such a system can have multiple positive equilibria within a stoichiometric class. The approach combines (i) the extension of the "Higher Deficiency Algorithm" of Ji and Feinberg for mass action systems to power-law...

The fundamental decomposition of a chemical reaction network (also called its “F-decomposition”) is the set of subnetworks generated by the partition of its set of reactions into the “fundamental classes” introduced by Ji and Feinberg in 2011 as the basis of their “higher deficiency algorithm” for mass action systems. The first part of this paper s...

This paper presents a computational solution to determine if a chemical reaction network endowed with power-law kinetics (PLK system) has the capacity for multistationarity, i.e., whether there exist positive rate constants such that the corresponding differential equations admit multiple positive steady states within a stoichiometric class. The ap...

The fundamental decomposition of a chemical reaction network (also called its "$\mathscr{F}$-decomposition") is the set of subnetworks generated by the partition of its set of reactions into the "fundamental classes" introduced by Ji and Feinberg in 2011 as the basis of their "higher deficiency algorithm" for mass action systems. The first part of...

The International Workshop on Mathematical Biology, or IWOMB, has already been held for two consecutive years in the Philippines. The first workshop was held on January 7-10, 2018 at Costabella Tropical Beach Resort, Cebu City, Philippines [1]. The second workshop was held on January 6-10, 2019 at Bohol Bee Farm, Bohol, Philippines [2]. Like a moth...

Glioblastoma multiforme is one of the most invasive type of glial tumors, which rapidly grows and commonly spreads into nearby brain tissue. It is a devastating brain cancer that often results in death within approximately 12 to 15 months after diagnosis. In this work, optimal control theory was applied to regulate intracellular signaling pathways...

Optimal control problem. Formulation of the optimal control problem for concomitant and alternating glucose and drug infusion. (PDF)

Dengue is endemic in the Philippines and poses a substantial economic burden in the country. In this work, a compartmentalized model which includes healthcare-seeking class is developed. The reproduction number is determined to investigate critical parameters influencing transmission. Partial rank correlation coefficient (PRCC) technique is perform...

The human cardiovascular system (CVS) and respiratory system (RS) work together in order to supply oxygen (O2) and other substrates needed for metabolism and to remove carbon dioxide (CO2). Global and local control mechanisms act on the CVS in order to adjust blood flow to the different parts of the body. This, in turn, affects the RS since the amo...

The human cardiovascular system (CVS) and respiratory system (RS) work together in order to supply O2 and other substrates needed for metabolism and to remove CO2. Global and local control mechanisms act on the CVS in order to adjust blood flow to the different parts of the body. This, in turn, affects the RS since the amount of O2 and CO2 transpor...

An SIJR-SI framework is considered to model the dynamics of the dengue disease in human population. With the emergence of a vaccine for dengue, early diagnosis and hospitalization drive, and public awareness for cleaner environment, our model includes control parameters. In particular, we investigate the effects of early diagnosis, hospitalization...

A method includes: receiving measurements of a blood-related parameter corresponding to a patient undergoing hemodialysis; estimating a value of one or more hemodialysis treatment-related parameters by applying a vascular refill model based on the received measurements of the blood-related parameter, wherein the one or more hemodialysis treatment-r...

An assessment of fluid status can be obtained by monitoring relative blood volume (RBV) during hemodialysis (HD) treatment. The dynamics of RBV is determined by fluid removal from the intravascular compartment by ultrafiltration (UF) and vascular refill from the interstitium. To characterize this dynamics, a two-compartment model describing the sho...

Glioblastoma, the most aggressive type of brain cancer, has median survival time of 1 year after diagnosis. It is characterized by alternating modes of rapid proliferation and aggressive invasion in response to metabolic stress in the microenvironment. A particular microRNA, miR-451, and its downstream signalling molecules, AMPK complex, are known...

In this study, a lumped compartment cardiovascular model is developed to predict pulsatile pressures in the systemic and pulmonary circulation as well as in finger arteries. Essential compartments of the model include arterial and venous pulmonary, left and right ventricles, and arterial and venous systemic compartments. A pulsatile left ventricle...

Intradialytic monitoring of relative blood volume (RBV) can be applied to assess fluid status and aid the prescription of ultrafiltration targets. RBV dynamics are clinically relevant and determined by 2 components: fluid removal from the intravascular compartment by ultrafiltration (UF) and vascular refill from the interstitium. We aimed to charac...

In this paper, we develop a pulsatile model for the cardiovascular system which describes the reaction of this system to a submaximal constant workload imposed on a person at a bicycle ergometer test after a period of rest. Furthermore, the model should allow to use measurements for the pulsatile pressure in fingertips which provide information on...

Glioblastoma multiforme (GBM) is an aggressive form of brain cancer with a median survival time of just about one year from the time of diagnosis. GBM is characterized by alternating phases of rapid proliferation and aggressive invasion as a response to metabolic stress in the microenvironment. In this paper, based on a recently formulated mathemat...

Inthisstudy,twoexistingmathematicalcardiovascularmod- els, a non-pulsatile global model and a simplified pulsatile left heart model were investigated, modified and combined. A global lumped compartment cardiovascular model was developed that could predict the pressures in the systemic and pulmonary circulation, and specifi- cally the pulsatile pres...

In this study we investigated, modified and combined two existing mathematical car-diovascular models, a non-pulsatile global model and a simplified pulsatile left heart model. The first goal of the study was to integrate these models. The main objective is to have a global lumped parameter pulsatile model that predicts the pressures in the systemi...