University of the Philippines
  • Quezon City, National Capital Region, Philippines
Recent publications
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 TB-HIV dual epidemic forms a lethal combination enhancing each other’s progress, driving the deterioration of immune responses. In order to understand and describe the transmission dynamics and epidemiological patterns of the co-infection, a compartmental model for TB-HIV is developed. A class of people living with HIV (PLHIV) who did not know their HIV status is incorporated into the model. These unaware PLHIV who do not seek medical treatment are potential sources of new HIV infections that could significantly influence the disease transmission dynamics. Sensitivity analysis using the partial rank correlation coefficient is performed to assess model parameters that are influential to the output of interests. The model is calibrated using available Philippine data on TB, HIV, and TB-HIV. Parameters that are identified include TB and HIV transmission rates, progression rates from exposed to active TB, and from TB-latent with HIV to active infectious TB with HIV in the AIDS stage. Uncertainty analysis is performed to identify the degree of accuracy of the estimates. Simulations predict an alarming increase of 180% and 194% in new HIV and TB-HIV infections in 2025, respectively, relative to 2019 data. These projections underscore an ongoing health crisis in the Philippines that calls for a combined and collective effort by the government and the public to take action against the lethal combination of TB and HIV.
Objective Disease activity monitoring in systemic lupus erythematosus (SLE) includes serial measurement of anti-double stranded-DNA (dsDNA) antibodies, but in patients who are persistently anti-dsDNA positive, the utility of repeated measurement is unclear. We investigated the usefulness of serial anti-dsDNA testing in predicting flare in SLE patients who are persistently anti-dsDNA positive. Methods Data were analysed from patients in a multinational longitudinal cohort with known anti-dsDNA results from 2013 to 2021. Patients were categorised based on their anti-dsDNA results as persistently negative, fluctuating or persistently positive. Cox regression models were used to examine longitudinal associations of anti-dsDNA results with flare. Results Data from 37,582 visits of 3,484 patients were analysed. 1,029 (29.5%) of patients had persistently positive anti-dsDNA and 1,195 (34%) had fluctuating results. Anti-dsDNA expressed as a ratio to the normal cut-off was associated with the risk of subsequent flare, including in the persistently positive cohort (adjusted hazard ratio (95% confidence interval) 1.56 (1.30, 1.87) (p < 0.001) and fluctuating cohort (adjusted HR (95%CI) 1.46 (1.28, 1.66)), both for a ratio >3. Both increases and decreases in anti-dsDNA more than two-fold compared to the previous visit were associated with increased risk of flare in the the fluctuating cohort (adjusted HR(95%CI) 1.33(1.08, 1.65) p = 0.008) and the persistently positive cohort (adjusted HR (95%CI) 1.36 (1.08, 1.71) p = 0.009). Conclusion Absolute value and change in anti-dsDNA titres predict flares, including in persistently anti-dsDNA positive patients. This indicates that repeat monitoring of dsDNA has value in routine testing.
Importance: Most epidemiological studies of heart failure (HF) have been conducted in high-income countries with limited comparable data from middle- or low-income countries. Objective: To examine differences in HF etiology, treatment, and outcomes between groups of countries at different levels of economic development. Design, setting, and participants: Multinational HF registry of 23 341 participants in 40 high-income, upper-middle-income, lower-middle-income, and low-income countries, followed up for a median period of 2.0 years. Main outcomes and measures: HF cause, HF medication use, hospitalization, and death. Results: Mean (SD) age of participants was 63.1 (14.9) years, and 9119 (39.1%) were female. The most common cause of HF was ischemic heart disease (38.1%) followed by hypertension (20.2%). The proportion of participants with HF with reduced ejection fraction taking the combination of a β-blocker, renin-angiotensin system inhibitor, and mineralocorticoid receptor antagonist was highest in upper-middle-income (61.9%) and high-income countries (51.1%), and it was lowest in low-income (45.7%) and lower-middle-income countries (39.5%) (P < .001). The age- and sex- standardized mortality rate per 100 person-years was lowest in high-income countries (7.8 [95% CI, 7.5-8.2]), 9.3 (95% CI, 8.8-9.9) in upper-middle-income countries, 15.7 (95% CI, 15.0-16.4) in lower-middle-income countries, and it was highest in low-income countries (19.1 [95% CI, 17.6-20.7]). Hospitalization rates were more frequent than death rates in high-income countries (ratio = 3.8) and in upper-middle-income countries (ratio = 2.4), similar in lower-middle-income countries (ratio = 1.1), and less frequent in low-income countries (ratio = 0.6). The 30-day case-fatality rate after first hospital admission was lowest in high-income countries (6.7%), followed by upper-middle-income countries (9.7%), then lower-middle-income countries (21.1%), and highest in low-income countries (31.6%). The proportional risk of death within 30 days of a first hospital admission was 3- to 5-fold higher in lower-middle-income countries and low-income countries compared with high-income countries after adjusting for patient characteristics and use of long-term HF therapies. Conclusions and relevance: This study of HF patients from 40 different countries and derived from 4 different economic levels demonstrated differences in HF etiologies, management, and outcomes. These data may be useful in planning approaches to improve HF prevention and treatment globally.
Nanocellulose is a promising nanomaterial that can be used in various applications such as reinforcements for composite films. Agricultural lignocellulosic wastes, such as coconut husks, offer great advantages as raw materials for nanocellulose extraction due to their abundance and economic viability. The aim of this study is to extract nanocellulose from matured coconut husk. Nanocellulose was extracted using sulfuric acid hydrolysis and characterized using Atomic Force Microscopy (AFM). Results showed that nanocellulose extracted from matured coconut husk has 2.26% yield with agglomerated, rod-shaped structures. An average aspect ratio of 3.16 ± 1.82 nm was also obtained.
Materials made from renewable resources offer a promising strategy for reducing environmental problems. Starch is a well-known alternative among several biodegradable materials due to its availability, cheap cost, and degradability. This research aims to develop a degradable film from cassava starch and use citric acid as the crosslinker. Light transmittance measurement reveals that the films produced have high UV barrier capacity in the UV region and above 80% transmittance values in the visible region. Additionally, it was found that the film with 10% citric acid had a favorable balance of tensile strength, elongation, and fracture stress.
Soft corals are zooxanthellate sessile animals supporting various organisms in coral reefs. However, their populations are threatened by the impacts of ocean warming. Under thermal stress conditions, soft corals may experience mild to severe bleaching which may lead to death. Understanding soft coral bleaching responses highlights the importance in predicting how populations and diversity may be affected by changing climate scenarios. In this study, we examined the bleaching responses of the three dominant soft coral genera (Lobophytum, n = 1318; Sarcophyton, n = 116; Sinularia, n = 639 colonies) in the Bolinao-Anda Reef Complex (BARC), Pangasinan, north-western Philippines during the 2020 thermal stress event in terms of genus and colony size susceptibility, and zooxanthellae density. Degree heating week (DHW) data from 1986–2020 were obtained using remotely sensed data to determine thermal anomalies in the study sites. The maximum DHW (6.3) in 2020 occurred between July–August while bleaching surveys were done during October of the same year. The percentage of bleached portions in each colony was used to determine bleaching category: no bleaching (0%), moderately bleached (1–50%) and heavily bleached (>50%). Quantification of bleaching prevalence and susceptibility of colony sizes were determined by colony count and mean diameter measurements taken from quadrat photographs in October 2020. Haphazard tissue collection (∼3 cm) in each colony of three soft coral genera per bleaching category was done to quantify zooxanthellae density. Results showed that Lobophytum colonies had the lowest bleaching prevalence (41%), followed by Sinularia (66%) and Sarcophyton (78%). All colony size classes of the three genera were susceptible to bleaching. However, smaller colonies of Lobophytum (<15 cm), Sarcophyton (<5 cm) and Sinularia (<5 cm) showed less susceptibility than large colonies. Zooxanthellae density was significantly reduced in moderately and heavily bleached colonies. The results of this study highlight that bleaching susceptibility is genus specific, with Sarcophyton and Sinularia being more susceptible to bleaching than Lobophytum. Smaller colonies seemed to be less susceptible to bleaching than large-sized soft corals suggesting a differential thermal stress response. Spatial variations in bleaching prevalence were also found among reef sites with varying environmental conditions and thermal stress histories. This work provided initial observations on how bleaching affects soft corals. Further studies on soft coral community recovery are recommended to fully understand how these organisms perform after thermal stress events.
This study delves into the microbial community complexity and its role in self-forming dynamic membrane (SFDM) systems, designed to remove nutrients and pollutants from wastewater, by means of the analysis of Next-Generation Sequencing (NGS) data. In these systems, microorganisms are naturally incorporated into the SFDM layer, which acts as a biological and physical filter. The microorganisms present in an innovative and highly efficient aerobic, electrochemically enhanced, encapsulated living membrane® bioreactor (e-LMBR) were studied to elucidate the nature of the dominant microbial communities present in sludge and encapsulated living membrane® layer (LM) of the experimental setup. The results were compared to those obtained from the microbial communities found in similar experimental reactors without an applied electric field. The data gathered from the NGS microbiome profiling showed that the microbial consortia found in the experimental systems are comprised of archaeal, bacterial, and fungal communities. However, the distribution of the microbial communities found in e-LMB and LMB had significant differences. The results showed that the presence of an intermittently applied electric field in e-LMB promotes the growth of some types of microorganisms (mainly electroactive microorganisms) responsible for the highly efficient treatment of the wastewater and for the mitigation of the membrane fouling found for those bioreactors.
This study analyzes how the Philippine government shapes gender norms through the awardees of an institutionalized award system called the “Presidential Awards for Filipino Individuals and Organizations Overseas” ( PAFIOO ). Publicly available biennial books of awardees that span 30 years (1991–2021) were obtained from the Commission on Filipinos Overseas archives, and the narrative data of the 342 awardees were thematically analyzed. This study argues that the state reinforces gender norms within migration and development through two identity frames bestowed on the winners of PAFIOO . First, the hero/heroine identity emphasizes the traditional views of gender roles, where women awardees, regardless of their civil status, are framed as sacrificing mother figures. Second, the commodity identity highlights men awardees and their masculine-related fields. Consequently, their contribution to development reflected this. Further, the PAFIOO selection is imbalanced, consistently awarding more men than women in the past three decades.
Plasma polymerization is a simple, solvent-free, dry process that involves vaporizing a monomer and ionizing them to the plasma state. This study reports the plasma polymerization of aniline in a direct current glow discharge. Aniline was introduced into a vacuum chamber and plasma-polymerized onto an indium-doped tin oxide/glass substrate at varying discharge potentials and deposition times. The resulting plasma-polymerized aniline films were in the leucoemeraldine form, as evidenced by UV-Vis and infrared spectral analyses. Monocarbon species that are products of the aromatic ring rupture were observed from the optical emission spectra of the discharge. The films reveal a smooth, pinhole-free surface across different process parameters. The film thickness from the 200 to 600 nm range presents a linear relationship with respect to the duration of deposition. The deposition rate also increased and has a good linear relationship when the discharge potential was varied.
This study explores the effect of atmospheric pressure plasma (APP) treatment on chitosan-acrylic acid (Cs-AA) blends. The experiment involves a custom-built APP setup used to modify a polymeric blend composed of natural (Cs) and synthetic (AA) polymers. Even with a low process temperature (<40 [Formula: see text]C), reactive oxygen and nitrogen species (RONS) were observed in an air plasma plume. The interaction of plasma with the liquid surface was also observed. With de-ionized water as the test liquid, the operating parameters such as the treatment time and flow rate were shown to influence the [Formula: see text]H and absorption spectrum of the liquid. The presence of RONS was investigated using optical emission spectroscopy coupled with principal component analysis. The analysis revealed that the air plasma contains the different N systems, NO, OH, H[Formula: see text], monatomic N, and monatomic O species. Varying the gas flow rate influences the production of NO and OH radicals while measuring plasma discharge in different conditions (ambient air, DI [Formula: see text]O, Cs, and Cs-AA blend) affects the concentration of the N positive and negative systems. The effect of these RONS on the Cs-AA blends was also investigated by assessing the chemical structure, [Formula: see text]H, and viscosity of the solution. In correlation with all of the findings, it was observed that plasma treatment could degrade pure Cs solution by dehydrogenation and glycosidic bond cleaving. However, the addition of AA reduces the degradation so that the AA radicals created by plasma form a complex with the Cs that reduces Cs fragmentation and chain entanglement, as observed in the reduction of viscosity. In summary, the rich reactive species created by plasma in the Cs-AA solution not only provided stable species but also introduced more Cs-AA complexes.
As the COVID-19 situation changes because of emerging variants and updated vaccines, an elaborate mathematical model is essential in crafting proactive and effective control strategies. We propose a COVID-19 mathematical model considering variants, booster shots, waning, and antiviral drugs. We quantify the effects of social distancing in the Republic of Korea by estimating the reduction in transmission induced by government policies from February 26, 2021 to February 3, 2022. Simulations show that the next epidemic peak can be estimated by investigating the effects of waning immunity. This research emphasizes that booster vaccination should be administered right before the next epidemic wave, which follows the increasing waned population. Policymakers are recommended to monitor the waning population immunity using mathematical models or other predictive methods. Moreover, our simulations considering a new variant’s transmissibility, severity, and vaccine evasion suggest intervention measures that can reduce the severity of COVID-19.
The degree of toxic metal and metalloid [metal(loid)] pollution in a tributary creek, which flows along a small-scale gold mining area, was assessed using modeled speciation profile and various environmental pollution indicators. Sediment and water samples were collected from five different locations representing the creek’s upstream, midstream, and downstream areas. Concentration of As, Cd, Cu, and Pb in the sediment and aqueous samples were determined. Chemical speciation of the target analytes in the creek system was performed using geochemical software PHREEQC utilizing elemental concentration in sediment and aqueous phase, temperature, pH, dissolved oxygen, and identified minerals as input values. The concentrations of the metal(loids) in the sediments of midstream and downstream were higher compared to the average shale value (ASV) and toxicological reference values (TRV). Similarly, the total concentrations of As and Cu in creek water exceeded the local guidelines for effluent waters. Speciation results identified HAsO4²⁻, Cd²⁺, CuOH⁺, and PbOH⁺ as the major species of the target analytes. Supersaturation of elements in sediment and low solubility in the aqueous matrix point out to resuspension and transport of metals as colloidal suspensions. The enrichment factor (EF) and geoaccumulation index (Igeo) values indicate significant levels of enrichment and pollution in the midstream and downstream areas. The increasing pollution load index (PLI) suggested the progressive deterioration from the upstream (0.8 to 1.7) down toward the midstream (PLI = 2.0 to 18.0) and downstream (PLI = 2.4 to 17.5). Speciation and environmental index results confirmed that anthropogenic sources in the midstream were transported to the downstream catchment.
The research studied the perception of Deaf college students on the use of a multimodal approach in teaching literacy to them. The research used a case study design to present five Deaf college students who underwent multimodal intervention sessions. The study primarily used qualitative data, supported by quantitative data from instrument scores. There were 10 intervention lessons that followed a scaffolded reading experience framework. Each lesson utilized all four modalities: linguistic, visual, socio-cultural, and kinesthetic. The intervention sessions were separate from the regular literature classes and lasted four months. Data were taken from pre- and post-intervention interview answers, independent work, and results of the QRI-5. Data were content analyzed by thematic analysis. Quantitative data, such as test scores and activities, were plotted to show individual performance. Findings suggested that comprehension is affected by the type of literature read, students’ prior knowledge, and availability of the modalities. The study showed that even though the Deaf are generally considered visual learners, the participants in the study prefer the integration of the different modalities for them to comprehend better. Recommendations include for teachers of the Deaf to consider tapping different modalities in teaching, as utilizing a multimodal approach brings out the uniqueness of each learner.
We demonstrate the formation of a condensate in a dark state of momentum states, in a pumped and shaken cavity-BEC system. The system consists of an ultracold quantum gas in a high-finesse cavity, which is pumped transversely by a phase-modulated laser. This phase-modulated pumping couples the atomic ground state to a superposition of excited momentum states, which decouples from the cavity field. We demonstrate how to achieve condensation in this state, supported by time-of-flight and photon emission measurements. With this, we show that the dark state concept provides a general approach to efficiently prepare complex many-body states in an open quantum system.
Microbial and chemical qualities of drinking water and freshwater bodies in highly urbanized regions of developing countries remain as global knowledge gaps. This current scoping review addressed this issue in the case of Mega Manila, Philippines. Quantitative and qualitative analyses of literature were done to support syntheses and identify gaps in water quality monitoring and management. The microbial quality of freshwater bodies and drinking water within the region is indicated by the detected microbial communities, bacterial species, and genetic elements associated with drug resistance, through culture-dependent and -independent approaches. Heavy metals were found to contaminate freshwater bodies but were absent in the drinking water supply. Overall, our findings highlight the need for harmonizing monitoring tools and data to assess water safety. Outside Mega Manila, freshwater bodies and drinking water supply must be monitored. Research focusing on environmental and public health as impacted by drinking water and resources must also be prioritized.
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24,591 members
Fe Josefa Nava
Teodoro Herbosa
  • Department of Emergency Medicine & Depaartment of Surgery
Jayson Cosme
  • National Institute of Physics
Lemnuel Aragones
  • Institute of Environmental Science and Meteorology
Quezon City, National Capital Region, Philippines