Clay–oil interactions play a critical role in determining the wettability of sandstone oil reservoirs, which, in turn, governs the effectiveness of enhanced oil recovery methods. In this study, we ...have measured the adhesion between –COOH functional groups and the siloxane and aluminol faces of kaolinite clay minerals by means of chemical force microscopy as a function of pH, salinity (from 0.001 M to 1 M) and cation identity (Na+ vs. Ca2+). Results from measurements on the siloxane face show that Ca2+ displays a reverse low-salinity effect (adhesion decreasing at higher concentrations) at pH 5.5, and a low salinity effect at pH 8. At a constant Ca2+ concentration of 0.001 M, however, an increase in pH leads to larger adhesion. In contrast, a variation in the Na+ concentration showed less effect in varying the adhesion of –COOH groups to the siloxane face. Measurements on the aluminol face showed a reverse low-salinity effect at pH 5.5 in the presence of Ca2+, whereas an increase in pH with constant ion concentration resulted in a decrease in adhesion for both Ca2+ and Na+. Results are explained by looking at the kaolinite’s surface complexation and the protonation state of the functional group, and highlight a more important role of the multicomponent ion exchange mechanism in controlling adhesion than the double layer expansion mechanism.
This thesis seeks to explore why some issues are more prominent than others. I seek to find
out why the debate on Genetic Engineering featured so prominently; whilst Nano-molecular
Technology (NMT) ...received little if no attention when it comes to its government policy
formulation. Using Agenda Setting Theory and Veto Player Theory, I seek to explain the
differences between the policy debate processes and its outcomes for the GM and NMT.
The findings of this thesis suggest Agenda Setting Theory failed to account for the lack of
change in policy on the issue of Genetic Engineering. It is argued that Veto Player Theory is
a better model for explaining policy outcomes and predicting the likelihood of policy
changes.
Despite extensive efforts to address it, the vastness of uncharacterized 'dark matter' microbial genetic diversity can impact short-read sequencing based metagenomic studies. Population-specific ...biases in genomic reference databases can further compound this problem. Leveraging advances in hybrid assembly (using short and long reads) and Hi-C technologies in a cross-sectional survey, we deeply characterized 109 gut microbiomes from three ethnicities in Singapore to comprehensively reconstruct 4497 medium and high-quality metagenome assembled genomes, 1708 of which were missing in short-read only analysis and with >28× N50 improvement. Species-level clustering identified 70 (>10% of total) novel gut species out of 685, improved reference genomes for 363 species (53% of total), and discovered 3413 strains unique to these populations. Among the top 10 most abundant gut bacteria in our study, one of the species and >80% of strains were unrepresented in existing databases. Annotation of biosynthetic gene clusters (BGCs) uncovered more than 27,000 BGCs with a large fraction (36-88%) unrepresented in current databases, and with several unique clusters predicted to produce bacteriocins that could significantly alter microbiome community structure. These results reveal significant uncharacterized gut microbial diversity in Southeast Asian populations and highlight the utility of hybrid metagenomic references for bioprospecting and disease-focused studies.
Background:Little is known about the effect of the coronavirus disease 2019 (COVID-19) pandemic and the outbreak response measures on door-to-balloon time (D2B). This study examined both D2B and ...clinical outcomes of patients with STEMI undergoing primary percutaneous coronary intervention (PPCI).Methods and Results:This was a retrospective study of 303 STEMI patients who presented directly or were transferred to a tertiary hospital in Singapore for PPCI from October 2019 to March 2020. We compared the clinical outcomes of patients admitted before (BOR) and during (DOR) the COVID-19 outbreak response. The study outcomes were in-hospital death, D2B, cardiogenic shock and 30-day readmission. For direct presentations, fewer patients in the DOR group achieved D2B time <90 min compared with the BOR group (71.4% vs. 80.9%, P=0.042). This was more apparent after exclusion of non-system delay cases (DOR 81.6% vs. BOR 95.9%, P=0.006). Prevalence of both out-of-hospital cardiac arrest (9.5% vs. 1.9%, P=0.003) and acute mitral regurgitation (31.6% vs. 17.5%, P=0.006) was higher in the DOR group. Mortality was similar between groups. Multivariable regression showed that longer D2B time was an independent predictor of death (odds ratio 1.005, 95% confidence interval 1.000–1.011, P=0.029).Conclusions:The COVID-19 pandemic and the outbreak response have had an adverse effect on PPCI service efficiency. The study reinforces the need to focus efforts on shortening D2B time, while maintaining infection control measures.
The aim of this study was to determine whether any change in degree of medial tibia plateau depression after extra-articular mechanical realignment surgery was observed in children with Blount's ...disease who presented late for treatment in their adolescence and young adulthood.
We retrospectively reviewed the radiographic parameters of 22 patients (32 lower limbs) with Blount's disease who underwent gradual correction of deformity using a ring external fixator without surgical elevation of the depressed medial tibial plateau at a mean age of 15 (range 10-37) years. Preoperative and postoperative angles of depressed medial tibia plateau (ADMTPs) of the same patient were compared for any significant change. Normally distributed data were analysed using Student's t -test when comparing two groups or one-way analysis of variance when comparing more than two groups. Skewed data were analysed using Mann-Whitney test.
After extra-articular mechanical alignment surgery, statistically significant improvements in medial tibial plateau depression were seen in the infantile ( P = 0.03) and juvenile ( P = 0.04) Blount's subgroups. Change in ADMTP was greater in patients who were operated on at age <17 years, before skeletal maturity ( P = 0.001). The improvement was likely due to ossification of unossified cartilage at the posteromedial proximal tibia and the remodelling potential of proximal tibia physis after mechanical realignment.
Improvement of medial tibia plateau depression is possible after mechanical realignment without surgical hemiplateau elevation in cases of infantile and juvenile Blount's disease that present late for treatment, especially when the operation is performed before 17 years of age.
Human complement receptor 1 (HuCR1) is a pivotal regulator of complement activity, acting on all three complement pathways as a membrane-bound receptor of C3b/C4b, C3/C5 convertase decay accelerator, ...and cofactor for factor I-mediated cleavage of C3b and C4b. In this study, we sought to identify a minimal soluble fragment of HuCR1, which retains the complement regulatory activity of the wildtype protein. To this end, we generated recombinant, soluble, and truncated versions of HuCR1 and compared their ability to inhibit complement activation in vitro using multiple assays. A soluble form of HuCR1, truncated at amino acid 1392 and designated CSL040, was found to be a more potent inhibitor than all other truncation variants tested. CSL040 retained its affinity to both C3b and C4b as well as its cleavage and decay acceleration activity and was found to be stable under a range of buffer conditions. Pharmacokinetic studies in mice demonstrated that the level of sialylation is a major determinant of CSL040 clearance in vivo. CSL040 also showed an improved pharmacokinetic profile compared with the full extracellular domain of HuCR1. The in vivo effects of CSL040 on acute complement-mediated kidney damage were tested in an attenuated passive antiglomerular basement membrane antibody-induced glomerulonephritis model. In this model, CSL040 at 20 and 60 mg/kg significantly attenuated kidney damage at 24 h, with significant reductions in cellular infiltrates and urine albumin, consistent with protection from kidney damage. CSL040 thus represents a potential therapeutic candidate for the treatment of complement-mediated disorders.
ObjectiveST segment elevation myocardial infarction (STEMI) is associated with significant mortality leading to loss of productive life years, especially in younger patients. This study aims to ...compare the characteristics and outcomes of young versus older patients with STEMI undergoing primary percutaneous coronary intervention (PPCI) to help focus public health efforts in STEMI prevention.MethodsData from the Coronary Care Unit database of the National University Hospital, Singapore from July 2015 to June 2019 were reviewed. Patients were divided into young (<50 years old) or older (≥50 years old) groups.ResultsOf the 1818 consecutive patients with STEMI who underwent PPCI, 465 (25.6%) were <50 years old. Young compared with older patients were more likely to be male, current smokers, of Indian ethnicity, have family history of ischaemic heart disease (IHD) and had lower 1 year mortality (3.4% vs 10.4%, p<0.0001). Although diabetes, hypertension or dyslipidaemia was less common among young patients, the prevalence of having any one of these risk factors was high in the range of 28% to 38%. Age was an independent predictor of mortality in the older but not younger patients with STEMI, and diabetes showed a trend towards mortality in both groups.ConclusionYoung patients with STEMI are more often smokers, of Indian ethnicity and had family history of IHD, although cardiometabolic risk factors are also prevalent. Mortality is lower, but not negligible, among the young patients with STEMI. Public health efforts are needed to reduce the prevalence of these risk factors among the constitutionally susceptible population.
•COVID-19 information from websites, social media, and broadcast protected against vaccine hesitancy.•Cyberbullying was associated with greater vaccine hesitancy only in unadjusted ...models.•Cyberbullying moderated the protective effects of broadcast information only.•Health communication should account for the detrimental effects of cyberbullying.
COVID-19 vaccination is an important public health intervention to curb the pandemic's magnitude and spread, and racial discrimination is a key predictor of COVID-19 preventive behavior, vaccine hesitancy, and uptake. This study evaluated the association of vaccine hesitancy with various modes of information on COVID-19 (i.e., online, social media) and the moderating role of cyberbullying among Asian Americans.
The authors used population-weighted data from the nationwide Asian American and Native Hawaiian/Pacific Islander COVID-19 Needs Assessment Survey, which was conducted from January 2021 to April, 2021 (unweighted N=3,127). The association between various modes of COVID-19 information and vaccine hesitancy, moderated by exposure to cyberbullying, were examined.
In general, 16% of Asian Americans reported vaccine hesitancy; 26% reported experiencing cyberbullying. Asian Americans reported receiving most COVID-19 information from online sources (75%) and social media (52%). In unadjusted models, receiving information via online (OR=0.46; 95% CI=0.33, 0.62; p<0.001), social media (OR=0.80; 95% CI=0.52, 0.93; p<0.05), and broadcast (OR=0.60; 95% CI=0.44, 0.81; p<0.001) were significantly associated with a lower vaccine hesitancy. However, reporting any cyberbullying was associated with increased vaccine hesitancy (OR=1.39; 95% CI=1.02, 1.90; p<0.05). The protective effects for COVID-19 information modes remained when accounting for health and sociodemographic factors, whereas the effect of cyberbullying was no longer statistically significant. Cyberbullying moderated the protective effect of broadcast information only, so those who received information via broadcast and reported experiencing cyberbullying had similar odds of vaccine hesitancy compared with those who did not receive information via broadcast.
Online, social media, and broadcast remain important sources of information about COVID-19 for Asian Americans; however, experiencing cyberbullying can reduce the effectiveness of these sources in the uptake of the vaccine. COVID-19 information promotion strategies for Asian Americans must account for the role of cyberbullying in social media campaigns.
Myopia is an emerging public health issue with potentially significant economic and social impact, especially in East Asia. However, many uncertainties about myopia and its clinical management ...remain. The International Myopia Summit workgroup was convened by the Singapore Eye Research Institute, the WHO Regional Office for the Western Pacific and the International Agency for the Prevention of Blindness in 2019. The aim of this workgroup was to summarise available evidence, identify gaps or unmet needs and provide consensus on future directions for clinical research in myopia. In this review, among the many ‘controversies in myopia’ discussed, we highlight three main areas of consensus. First, development of interventions for the prevention of axial elongation and pathologic myopia is needed, which may require a multifaceted approach targeting the Bruch’s membrane, choroid and/or sclera. Second, clinical myopia management requires co-operation between optometrists and ophthalmologists to provide patients with holistic care and a tailored approach that balances risks and benefits of treatment by using optical and pharmacological interventions. Third, current diagnostic technologies to detect myopic complications may be improved through collaboration between clinicians, researchers and industry. There is an unmet need to develop new imaging modalities for both structural and functional analyses and to establish normative databases for myopic eyes. In conclusion, the workgroup’s call to action advocated for a paradigm shift towards a collaborative approach in the holistic clinical management of myopia.
Background:
Infectious control measures during the COVID-19 pandemic have led to the propensity toward telemedicine. This study examined the impact of telemedicine during the pandemic on the ...long-term outcomes of ST-segment elevation myocardial infarction (STEMI) patients.
Methods:
This study included 288 patients admitted 1 year before the pandemic (October 2018–December 2018) and during the pandemic (January 2020–March 2020) eras, and survived their index STEMI admission. The follow-up period was 1 year. One-year primary safety endpoint was all-cause mortality. Secondary safety endpoints were cardiac readmissions for unplanned revascularisation, non-fatal myocardial infarction, heart failure, arrythmia, unstable angina. Major adverse cardiovascular events (MACE) was defined as the composite outcome of each individual safety endpoint.
Results:
Despite unfavorable in-hospital outcomes among patients admitted during the pandemic compared to pre-pandemic era, both groups had similar 1-year all-cause mortality (11.2 vs. 8.5%, respectively,
p
= 0.454) but higher cardiac-related (14.1 vs. 5.1%,
p
< 0.001) and heart failure readmissions in the pandemic vs. pre-pandemic groups (7.1 vs. 1.7%,
p
= 0.037). Follow-up was more frequently conducted via teleconsultations (1.2 vs. 0.2 per patient/year,
p
= 0.001), with reduction in physical consultations (2.1 vs. 2.6 per patient/year,
p
= 0.043), during the pandemic vs. pre-pandemic era. Majority achieved guideline-directed medical therapy (GDMT) during pandemic vs. pre-pandemic era (75.9 vs. 61.6%,
p
= 0.010). Multivariable Cox regression demonstrated achieving medication target doses (HR 0.387, 95% CI 0.164–0.915,
p
= 0.031) and GDMT (HR 0.271, 95% CI 0.134–0.548,
p
< 0.001) were independent predictors of lower 1-year MACE after adjustment.
Conclusion:
The pandemic has led to the wider application of teleconsultation, with increased adherence to GDMT, enhanced medication target dosing. Achieving GDMT was associated with favorable long-term prognosis.
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