A clinical diagnostic model for predicting influenza among young adult military personnel with febrile respiratory illness in Singapore

10.1371/journal.pone.0017468PLoS ONE63

Respiratory viral pathogens among Singapore military servicemen 2009 - 2012: Epidemiology and clinical characteristics

10.1186/1471-2334-14-204BMC Infectious Diseases141-BIDM

Design of Absorption Enhanced Organic Solar Cell

One of the major reasons for the reported low power conversion efficiency (PCE) of organic solar cell is the fact that organic material has generally short exciton diffusion length where only thin active material is made possible in the organic solar cell structure. To compensate for the low light absorption issue due to the thin photoactive layer of the device, various light trapping techniques have been introduced in past solar cell designs to address the light absorption issue and hence the PCE. This research work is to systematically study on two light trapping techniques, namely plasmonic resonance effect techniques and anti-surface reflection technique with an attempt to enhance the light absorption capability. This enhanced absorption cell would eventually contribute to the PCE of the solar cell. These are achieved by means of incorporating NPs into the solar cell layer structure as well as the application of anti reflection coating on the solar cell. Finite difference time domain (FDTD) based simulation tool known as Lumerical is deployed to study how design parameters such as NPs diameter, spacing period, material and various configurations of anti-reflection coating (ARC) structures to improve and enhance light absorption

Passage Adaptation Correlates With the Reduced Efficacy of the Influenza Vaccine.

BACKGROUND:As a dominant seasonal influenza virus, H3N2 virus rapidly evolves in humans and is a constant threat to public health. Despite sustained research efforts, the efficacy of H3N2 vaccine has decreased rapidly. Even though antigenic drift and passage adaptation (substitutions accumulated during vaccine production in embryonated eggs) have been implicated in reduced vaccine efficacy (VE), their respective contributions to the phenomenon remain controversial. METHODS:We utilized mutational mapping, a powerful probabilistic method for studying sequence evolution, to analyze patterns of substitutions in different passage conditions for an unprecedented amount of H3N2 hemagglutinin sequences (n = 32 278). RESULTS:We found that passage adaptation in embryonated eggs is driven by repeated convergent evolution over 12 codons. Based on substitution patterns at these sites, we developed a metric, adaptive distance (AD), to quantify the strength of passage adaptation and subsequently identified a strong negative correlation between AD and VE. CONCLUSIONS:The high correlation between AD and VE implies that passage adaptation in embryonated eggs may be a strong contributor to the recent reduction in H3N2 VE. We developed a computational package called MADE (Measuring Adaptive Distance and vaccine Efficacy based on allelic barcodes) to measure the strength of passage adaptation and predict the efficacy of a candidate vaccine strain. Our findings shed light on strategies for reducing Darwinian evolution within the passaging medium in order to potentially restore an effective vaccine program in the future

A System Based-Approach to Examine Cytokine Response in Poxvirus-Infected Macrophages

The poxviruses are large, linear, double-stranded DNA viruses about 130 to 230 kbp, that have an animal origin and evolved to infect a wide host range. Variola virus (VARV), the causative agent of smallpox, is a poxvirus that infects only humans, but other poxviruses such as monkey poxvirus and cowpox virus (CPXV) have crossed over from animals to infect humans. Therefore understanding the biology of poxviruses can devise antiviral strategies to prevent these human infections. In this study we used a system-based approach to examine the host responses to three orthopoxviruses, CPXV, vaccinia virus (VACV), and ectromelia virus (ECTV) in the murine macrophage RAW 264.7 cell line. Overall, we observed a significant down-regulation of gene expressions for pro-inflammatory cytokines, chemokines, and related receptors. There were also common and virus-specific changes in the immune-regulated gene expressions for each poxvirus-infected RAW cells. Collectively our results showed that the murine macrophage RAW 264.7 cell line is a suitable cell-based model system to study poxvirus host response

A point prevalence survey to assess antibiotic prescribing in patients hospitalized with confirmed and suspected coronavirus disease 2019 (COVID-19)

Background: Earlier studies have reported high antibiotic use in patients hospitalised for coronavirus disease 2019 (COVID-19), resulting in concerns of increasing antimicrobial resistance with increase antibiotic use in this pandemic. Point prevalence survey (PPS) can be a quick tool to provide antibiotic prescribing information to aid antimicrobial stewardship (AMS) activities. Objectives: To describe antibiotic utilization and evaluate antibiotic appropriateness in COVID-19 patients using PPS. Methods: Adapting Global-PPS on antimicrobial use, the survey was conducted in COVID-19 wards at 2 centres in Singapore on 22 April 2020 at 0800h. Patients on systemic antibiotics were included and evaluated for antibiotic appropriateness. Results: Five hundred and seventy-seven patients were screened. Thirty-six (6.2%) patients were on antibiotics and which were started at median of 7 days (inter-quartile rate (IQR), 4, 11) from symptom onset. Fifty-one antibiotics were prescribed in these patients. Overall, co-amoxiclav (26/51, 51.0%) was the most often prescribed antibiotic. Thirty-one out of 51 (60.8%) antibiotic prescriptions were appropriate. Among 20 inappropriate prescriptions, 18 (90.0%) were initiated in patients with low likelihood of bacterial infections. Antibiotic prescriptions were more appropriate when reviewed by infectious diseases physicians (13/31 [41.9%] versus 2/20 [10.0%], p = 0.015), and if reasons for use were stated in notes (31/31 [100.0%] versus 16/20 [80.0%], p = 0.019). Conclusions: Despite low prevalence of antibiotic use among confirmed and suspected COVID-19 patients at 2 centres in Singapore, there was significant proportion of inappropriate antibiotics use where bacterial infections were unlikely. AMS teams can tailor stewardship strategies using PPS results

Effects of coronavirus disease 2019 (COVID-19) pandemic on antimicrobial prevalence and prescribing in a tertiary hospital in Singapore

10.1186/s13756-021-00898-8Antimicrobial Resistance and Infection Control1012

Antibiotic Therapy in the Treatment of COVID-19 Pneumonia: Who and When?

Background: COVID-19 imposes challenges in antibiotic decision-making due to similarities between bacterial pneumonia and moderate to severe COVID-19. We evaluated the effects of antibiotic therapy on the clinical outcomes of COVID-19 pneumonia patients and diagnostic accuracy of key inflammatory markers to inform antibiotic decision-making. Methods: An observational cohort study was conducted in patients hospitalised with COVID-19 at the National Centre for Infectious Diseases and Tan Tock Seng Hospital, Singapore, from January to April 2020. Patients were defined as receiving empiric antibiotic treatment for COVID-19 if started within 3 days of diagnosis. Results: Of 717 patients included, 86 (12.0%) were treated with antibiotics and 26 (3.6%) had documented bacterial infections. Among 278 patients with COVID-19 pneumonia, those treated with antibiotics had more diarrhoea (26, 34.7% vs. 24, 11.8%, p p = 0.384). Antibiotic treatment was not independently associated with lower 30-day (adjusted odds ratio, aOR 19.528, 95% confidence interval, CI 1.039–367.021) or in-hospital mortality (aOR 3.870, 95% CI 0.433–34.625) rates after adjusting for age, co-morbidities and severity of COVID-19 illness. Compared to white cell count and procalcitonin level, the C-reactive protein level had the best diagnostic accuracy for documented bacterial infections (area under the curve, AUC of 0.822). However, the sensitivity and specificity were less than 90%. Conclusion: Empiric antibiotic use in those presenting with COVID-19 pneumonia did not prevent deterioration or mortality. More studies are needed to evaluate strategies to diagnose bacterial co-infections in these patients

Hydro gel light-guiding conjunction for absorptive type multi-ions detection

We present a novel miniaturized solid state sensor produced by embedding two optical fibers in a sensing hydro gel conjunction. The conjunction is a poly (2-hydroxyethyl methacrylate) (poly HEMA) hydro gel mixed with two kinds of selective fluorescent probes. Meso-2,6-Dichlorophenyltripyrrinone (TPN-Cl2) is used to react with zinc ion (Zn2+) and the synthesized “Chemosensor 1” is used to detect ferric ion (Fe3+). This hydro gel conjunction can serve as a light-guiding waveguide that allows light signals to transfer between two fibers. By using a multi-wavelength excitation light, a mixed solution that contains Zn2+ and Fe3+ can be detected in real-time. This miniaturized sensor develops an image for real-time monitoring of Zn2+ and Fe3+ ions in vivo