Direct Analytical Modeling for Optimal, On-Design Performance of Ejector for Simulating Heat-Driven Systems

This paper describes an ejector model for the prediction of on-design performance under available conditions. This is a direct method of calculating the optimal ejector performance (entrainment ratio or ER) without the need for iterative methods, which have been conventionally used. The values of three ejector efficiencies used to account for losses in the ejector are calculated by using a systematic approach (by employing CFD analysis) rather than the hit and trial method. Both experimental and analytical data from literature are used to validate the presented analytical model with good agreement for on-design performance. R245fa working fluid has been used for low-grade heat applications, and Engineering Equation Solver (EES) has been employed for simulating the proposed model. The presented model is suitable for integration with any thermal system model and its optimization because of its direct, non-iterative methodology. This model is a non-dimensional model and therefore requires no geometrical dimensions to be able to calculate ejector performance. The model has been validated against various experimental results, and the model is employed to generate the ejector performance curves for R245fa working fluid. In addition, system simulation results of the ejector refrigeration system (ERS) and combined cooling and power (CCP) system have been produced by using the proposed analytical model

Association of Television Viewing Time with Body Composition and Calcified Subclinical Atherosclerosis in Singapore Chinese

Objective: Sedentary behavior such as television viewing may be an independent risk factor for coronary heart disease. However, few studies have assessed the impact of television viewing time on coronary artery calcification and it remains unclear how body fat contributes to this relationship. The aim of this study is to evaluate the association between television viewing time and subclinical atherosclerosis and whether effects on visceral or subcutaneous fat may mediate any associations observed. Methods: This was a cross-sectional study of 398 Chinese participants (192 men and 206 women) from Singapore prospective study. Participants were free from known cardiovascular diseases and underwent interview, health screening, computed tomography scans of coronary arteries and abdomen. Spearman’s correlation was used to test the correlation between television viewing time, physical activity, body composition and abdominal fat distribution. The association between television viewing time and subclinical atherosclerosis was assessed by multiple logistic regression analysis. Results: In men, television viewing time was significantly correlated with higher body fat mass index, percent body fat, subcutaneous and visceral fat. These associations were in the same direction, but weaker and not statistically significant in women. Television viewing time (hours/day) was associated with subclinical atherosclerosis in men (odds ratio: 1.41, 95% CI: 1.03-1.93) but no significant association was observed in women (odds ratio: 0.88, 95% CI: 0.59-1.31) after adjusting for potential socio-demographic and lifestyle confounders. Further adjustments for biological factors did not affect these associations. Conclusions: Television viewing time was associated with greater adiposity and higher subcutaneous and visceral fat in men. TV viewing time was also associated with subclinical atherosclerosis in men and the potential mechanisms underlying this association require further investigation

Associations Between Maternal Distress During Early Life Periods and Offspring Respiratory Infections and Allergic Outcomes

DOI does not function. It has been reported to the journal 28.12.2022BackgroundIncreasing evidence suggests that maternal distress is a risk factor for development of respiratory infections and allergic diseases in the offspring. We aim to evaluate the link between maternal distress during critical periods in early life, namely the preconception, pregnancy and postnatal periods, and development of respiratory infections and allergic diseases in the offspring from the Singapore PREconception Study of long Term maternal and child Outcomes (S-PRESTO) cohort. MethodsMaternal perceived distress was evaluated using validated questionnaires including Beck Depression Inventory-II (BDI-II) administered during three time periods: preconception (three months apart at four timepoints), pregnancy (during each trimester) and postnatal (3 and 6 months post-delivery). Child eczema, rhinitis and wheeze outcomes were evaluated using a modified ISAAC questionnaire at ages 3, 6, 12, and 18 months. Child allergic sensitization was determined by skin prick testing at 18 months. ResultsAmong 332 mother-child pairs studied, higher maternal distress during preconception and pregnancy increased the risks of wheeze development in the first 18 months; for example, preconception and pregnancy BDI-II scores >= 20 were associated with increased risks of wheeze by 18 months [adjusted risk ratios 3.2 (95%CI 1.1-9.4) and 2.5 (1.0-5.9), respectively]. Emotional and practical support from family during preconception decreased the risks of offspring wheeze. No associations were observed between maternal distress and offspring eczema, rhinitis and allergic sensitization. ConclusionMaternal distress during critical early life periods was associated with offspring wheeze in the first 18 months of life. Supporting maternal mental health even before pregnancy could reduce the risk of offspring wheeze.Peer reviewe

Improving pre-roll advertisements through the use of congruence

Over the last decade, the field of advertising has expanded rapidly to include new formats such as online videos. The purpose of the current study is to investigate the effects of ad congruence (ad-context congruence and ad-profile congruence) on attitudes towards the ad and the brand in the new context of pre-roll advertisements. A total of 80 participants took part in a laboratory experiment where three pre-roll advertisements were paired with short videos. The results (n = 80) showed significant main effects of ad-context congruence on perceived irritation and attitude towards the ad. The results also showed significant main effects of ad-profile congruence on perceived manipulative intent and attitude towards the brand. In addition, the results indicated that perceived irritation was a significant mediator for the effect of ad-context congruence on attitudes towards the ad and the brand. Perceived manipulative intent was also found to be a significant mediator for the effect of ad-profile congruence on attitudes towards the ad and the brand. Theoretical implications with respect to different psychological mechanisms underlying ad-content and ad-profile congruence, as well as practical implications for advertisers to maximise the effectiveness of pre-roll advertisements are discussed.Bachelor of Communication Studie

Aedes (Stegomyia) albopictus (Skuse) : a potential vector of Zika virus in Singapore

Background: Zika virus (ZIKV) is a little known arbovirus until it caused a major outbreak in the Pacific Island of Yap in 2007. Although the virus has a wide geographic distribution, most of the known vectors are sylvatic Aedes mosquitoes from Africa where the virus was first isolated. Presently, Ae. aegypti is the only known vector to transmit the virus outside the African continent, though Ae. albopictus has long been a suspected vector. Currently, Ae. albopictus has been shown capable of transmitting more than 20 arboviruses and its notoriety as an important vector came to light during the recent chikungunya pandemic. The vulnerability of Singapore to emerging infectious arboviruses has stimulated our interest to determine the competence of local Ae. albopictus to transmit ZIKV. Methodology/Principal Findings: To determine the competence of Ae. albopictus to ZIKV, we orally infected local mosquito strains to a Ugandan strain virus. Fully engorged mosquitoes were maintained in an environmental chamber set at 29°C and 80–85%RH. Twelve mosquitoes were then sampled daily from day one to seven and on day 10 and 14 post infection (pi). Zika virus titre in the midgut and salivary glands of each mosquito were determined using tissue culture infectious dose50 assay, while transmissibility of the virus was determined by detecting viral antigen in the mosquito saliva by qRT-PCR. High dissemination and transmission rate of ZIKV were observed. By day 7-pi, all mosquitoes have disseminated infection and 73% of these mosquitoes have ZIKV in their saliva. By day 10-pi, all mosquitoes were potentially infectious. Conclusions/Significance: The study highlighted the potential of Ae. albopictus to transmit ZIKV and the possibility that the virus could be established locally. Nonetheless, the threat of ZIKV can be mitigated by existing dengue and chikungunya control program being implemented in Singapore.Published versio

Precision Medicine for Nasopharyngeal Cancer—A Review of Current Prognostic Strategies

Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV) driven malignancy arising from the nasopharyngeal epithelium. Current treatment strategies depend on the clinical stage of the disease, including the extent of the primary tumour, the extent of nodal disease, and the presence of distant metastasis. With the close association of EBV infection with NPC development, EBV biomarkers have shown promise in predicting treatment outcomes. Among the omic technologies, RNA and miRNA signatures have been widely studied, showing promising results in the research setting to predict treatment response. The transformation of radiology images into measurable features has facilitated the use of radiomics to generate predictive models for better prognostication and treatment selection. Nonetheless, much of this work remains in the research realm, and challenges remain in clinical implementation

Kesan transglutaminase kepada ciri fizikokimia dan aktiviti biologi hidrolisat sarang burung walit

Kajian terdahulu menunjukkan bahawa glikoprotein sarang burung walit boleh dihidrolisis dan dipulihkan sebagai hidrolisat sarang burung walit (SBWh) yang boleh dimakan dalam bentuk serbuk. Kajian ini adalah kerja sambungan daripada kajian terdahulu, yang mana pelbagai kepekatan enzim transglutaminase (TG) telah digunakan dalam pembentukan semula bentuk serbuk SBWh menggunakan acuan dan kesannya terhadap sifat fizikokimia dan bioaktiviti SBWh. Proses hidrolisis enzim menunjukkan bahawa sampel SBWh mempunyai hasil pulih lebih daripada 60% dan menunjukkan warna yang lebih terang daripada SBW mentah. Kelarutan SBWh dengan TG lebih rendah tetapi ia boleh dibentuk semula ke bentuk yang diingini. Corak spektrum FTIR untuk sampel SBWh juga menunjukkan bahawa ketulenan glikopeptida SBW yang tinggi telah diperoleh. Untuk aktiviti antioksidan, produk sampingan SBWh (SBWhcp) menunjukkan aktiviti penyingkiran radikal bebas DPPH yang lebih tinggi. Secara ringkasnya, penambahan TG kepada SBWh telah meningkatkan sifat fizikokimia dan bioaktiviti. Penemuan ini menghasilkan wawasan tentang aplikasi dan pembangunan produk EBN menggunakan EBNh dengan TG yang mempunyai bioaktiviti yang tinggi

Effects of starch filler on the physical properties of lyophilized calcium–alginate beads and the viability of encapsulated cells

The main objective of this work is to improve the physical properties of lyophilized calcium (Ca)–alginate beads as a carrier material for the stabilization of encapsulated living cells. Improvements in the sphericity, flowability and mechanical strength of the dried beads were attributed to the filler, which provided structure and reinforcement to the Ca–alginate hydrogel networks, as verified by X-ray microtomography and scanning electron microscopy. A quantitative analysis of the micro-images revealed the less porous nature of the alginate–starch beads compared to the control. The beads with filler were also found to be less hygroscopic. The results also show that the cells encapsulated within the beads with reduced porosity and hygroscopicity were clearly more stable during lyophilization and storage than the control. In conclusion, the qualities of the alginate beads were improved by incorporating the solid filler, and the filler had a significant influence on cell viability during lyophilization and storage