Polarity-Induced Reactive Wetting: Spreading and Retracting Sessile Water Drops.

Wetting is typically defined by the relative liquid to solid surface tension/energy, which are composed of polar and nonpolar subcontributions. Current studies often assume that they remain invariant, that is, surfaces are wetting-inert. Complex wetting scenarios, such as adaptive or reactive wetting processes, may involve time-dependent variations in interfacial energies. To maximize differences in energetic states, we employ low-energy perfluoroalkyls integrated with high-energy silica-based polar moieties grown on low-energy polydimethylsiloxane. To this end, we tune the hydrophilic-like wettability on these perfluoroalkyl-silica-polydimethylsiloxane surfaces. Drop contact behaviors range from invariantly hydrophobic at ca. 110° to rapidly spreading at ca. 0° within 5 s. Unintuitively, these vapor-grown surfaces transit toward greater hydrophilicity with increasing perfluoroalkyl deposition. Notably, this occurs as sequential silica-and-perfluoroalkyl deposition also leaves behind embedded polar moieties. We highlight how surfaces having such chemical heterogeneity are inherently wetting-reactive. By creating an abrupt wetting transition composed of reactive and inert domains, we introduce spatial dependency. Drops contacting the transition spread before retracting, occurring over the time scale of a few seconds. This phenomenon contradicts current understanding, exhibiting a uniquely (1) decreasing advancing contact angle and (2) increasing receding contact angle. To explain the behavior, we model such time- and space- dependent reactive wetting using first order kinetics. In doing so, we explore how reactive and recovery mechanisms govern the characteristic time scales of spreading and retracting sessile drops

Willingness of Hong Kong healthcare workers to accept pre-pandemic influenza vaccination at different WHO alert levels: two questionnaire surveys

Objective To assess the acceptability of pre-pandemic influenza vaccination among healthcare workers in public hospitals in Hong Kong and the effect of escalation in the World Health Organization’s alert level for an influenza pandemic

Promoting resilience for HIV prevention in female sex workers in Hong Kong: a randomised controlled trial

Background: Female sex workers are considered a reservoir of HIV and their psychological health has a role to play in HIV infections. In China, commercial sex workers were reported to account for nearly 50% of heterosexual transmission of HIV. Therefore, HIV prevention targeted at mental health could be an innovative strategy in controlling the infection. We aimed to provide an evidence-based resilience-promoting intervention targeting mental health and ultimately safe sexual practices of female sex workers. Methods: This randomised controlled trial was done at three Hong Kong non-governmental organisations, namely Action for REACH OUT, JJJ Association, and the Society of Rehabilitation and Crime Prevention. Participants in this study were women (aged ≥18 years) who had worked as a sex worker in the previous 6 months. We randomly assigned participants to either intervention or usual care (control) according to a predetermined, computer-generated randomisation list. Both group facilitator and partcipants were unmasked to the group allocation, but an independent researcher who was masked to the treatment allocation administered the questionnaires. About half of the participants were permanent residents of Hong Kong whereas the other half were from mainland China. The six-session resilience-promoting intervention was designed to improve the coping skills, self-esteem, and self-efficacy (i.e. the belief of an individuals’ ability to control their actions to achieve desired goal), as measured by Brief-COPE, the Rosenberg Self-esteem Scale, and the Generalised Self- efficacy Scale of female sex workers. Questionnaires were administered by an independent assessor at baseline, post-treatment, and at 3-months follow-up. Participants in the control group received standard service, which included outreach visits, screening for HIV or sexually transmitted infections, and social activities provided by non-governmental organisations. The primary outcome of this study was the resilience scores measured by Connor-Davidson Resilience Scale. We analysed the differences between the two groups using the intention-to-treat analysis. This study was approved by the University of Hong Kong/Hospital Authority Hong Kong West Cluster Internal Review Board (UW 12-220). Verbal informed consent was obtained from all participants. Findings: 127 female sex workers were randomly assigned: 64 joined the control group and 63 joined intervention group. There were significant differences on the score on resilience, self-esteem, and mental health status between groups at post-intervention and 3- month follow-up. We found that condom use in the intervention group at 3-month follow-up was improved compared with the control group. After controlling for marital status and family size, improved resilience scores were associated with intervention group assignment (odds ratio 2∙95 [95% CI 1∙19–7∙35]; p=0∧021) and self-efficacy (1∧13 [1∧03–1∧24]; p=0∧006). Interpretation: Our findings suggest that resilience-promoting intervention programme was effective in improving the mental health status among Chinese female sex workers. This programme is an innovative approach to HIV prevention by promoting both psychological well-being and safe sex for this high-risk population. Funding: Council for the AIDS Trust Fund and General Research Grant, Research Grants Council, HKSAR

Wetting on silicone surfaces

Silicone is frequently used as a model system to investigate and tune wetting on soft materials. Silicone is biocompatible and shows excellent thermal, chemical, and UV stability. Moreover, the mechanical properties of the surface can be easily varied by several orders of magnitude in a controlled manner. Polydimethylsiloxane (PDMS) is a popular choice for coating applications such as lubrication, self-cleaning, and drag reduction, facilitated by low surface energy. Aiming to understand the underlying interactions and forces, motivated numerous and detailed investigations of the static and dynamic wetting behavior of drops on PDMS-based surfaces. Here, we recognize the three most prevalent PDMS surface variants, namely liquid-infused (SLIPS/LIS), elastomeric, and liquid-like (SOCAL) surfaces. To understand, optimize, and tune the wetting properties of these PDMS surfaces, we review and compare their similarities and differences by discussing (i) the chemical and molecular structure, and (ii) the static and dynamic wetting behavior. We also provide (iii) an overview of methods and techniques to characterize PDMS-based surfaces and their wetting behavior. The static and dynamic wetting ridge is given particular attention, as it dominates energy dissipation, adhesion, and friction of sliding drops and influences the durability of the surfaces. We also discuss special features such as cloaking and wetting-induced phase separation. Key challenges and opportunities of these three surface variants are outlined

Gene network exploration of crosstalk between apoptosis and autophagy in chronic myelogenous leukemia

Copyright © 2015 Fengfeng Wang et al. Background. Gene expression levels change to adapt the stress, such as starvation, toxin, and radiation. The changes are signals transmitted through molecular interactions, eventually leading to two cellular fates, apoptosis and autophagy. Due to genetic variations, the signals may not be effectively transmitted to modulate apoptotic and autophagic responses. Such aberrant modulation may lead to carcinogenesis and drug resistance. The balance between apoptosis and autophagy becomes very crucial in coping with the stress. Though there have been evidences illustrating the apoptosis-autophagy interplay, the underlying mechanism and the participation of the regulators including transcription factors (TFs) and microRNAs (miRNAs) remain unclear. Results. Gene network is a graphical illustration for exploring the functional linkages and the potential coordinate regulations of genes. Microarray dataset for the study of chronic myeloid leukemia was obtained from Gene Expression Omnibus. The expression profiles of those genes related to apoptosis and autophagy, including MCL1, BCL2, ATG, beclin-1, BAX, BAK, E2F, cMYC, PI3K, AKT, BAD, and LC3, were extracted from the dataset to construct the gene networks. Conclusion. The network analysis of these genes explored the underlying mechanisms and the roles of TFs and miRNAs for the crosstalk between apoptosis and autophagy.Link_to_subscribed_fulltex

Cryofouling avoidance in the Antarctic scallop Adamussium colbecki

The presence of supercooled water in polar regions causes anchor ice to grow on submerged objects, generating costly problems for engineered materials and life-endangering risks for benthic communities. The factors driving underwater ice accretion are poorly understood, and passive prevention mechanisms remain unknown. Here we report that the Antarctic scallop Adamussium colbecki appears to remain ice-free in shallow Antarctic marine environments where underwater ice growth is prevalent. In contrast, scallops colonized by bush sponges in the same microhabitat grow ice and are removed from the population. Characterization of the Antarctic scallop shells revealed a hierarchical micro-ridge structure with sub-micron nano-ridges which promotes directed icing. This concentrates the formation of ice on the growth rings while leaving the regions in between free of ice, and appears to reduce ice-to-shell adhesion when compared to temperate species that do not possess highly ordered surface structures. The ability to control the formation of ice may enable passive underwater anti-icing protection, with the removal of ice possibly facilitated by ocean currents or scallop movements. We term this behavior cryofouling avoidance. We posit that the evolution of natural anti-icing structures is a key trait for the survival of Antarctic scallops in anchor ice zones.This work was supported by the European Union’s Horizon 2020 research and innovation program LubISS No. 722497 (W.S.Y.W.), the German Research Foundation (DFG) with the Priority Programme 2171 (L.H.), the NSF Award No. OPP 1559691 (P.A.C.). The Antarctic fieldwork was supported by the US Antarctic Program under OPP 1559691 to P.A.C. and OPP 1341612 to S. Bowser. We thank S. Bowser, H. Kaiser, and M. Koonce for their assistance in the field, G. Glaser, R. Berger, H. Burg for technical support, A. Naga, D. Vollmer, H.-J. Butt, and M. Bonn for stimulating discussions and the reviewers L. Harper and J. Raymond, whose comments helped to improve this manuscript.Ye

Renal screening in children after exposure to low dose melamine in Hong Kong: cross sectional study

Objective To investigate the renal outcomes of children after exposure to low dose melamine in Hong Kong

Implications of MicroRNAs in the treatment of gefitinib-resistant non-small cell lung cancer

2015-2016 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Determinants of medication adherence to antihypertensive medications among a Chinese population using Morisky medication adherence scale

<b>Background and objectives</b> Poor adherence to medications is one of the major public health challenges. Only one-third of the population reported successful control of blood pressure, mostly caused by poor drug adherence. However, there are relatively few reports studying the adherence levels and their associated factors among Chinese patients. This study aimed to study the adherence profiles and the factors associated with antihypertensive drug adherence among Chinese patients.<p></p> <b>Methods</b> A cross-sectional study was conducted in an outpatient clinic located in the New Territories Region of Hong Kong. Adult patients who were currently taking at least one antihypertensive drug were invited to complete a self-administered questionnaire, consisting of basic socio-demographic profile, self-perceived health status, and self-reported medication adherence. The outcome measure was the Morisky Medication Adherence Scale (MMAS-8). Good adherence was defined as MMAS scores greater than 6 points (out of a total score of 8 points).<p></p> <b>Results</b> From 1114 patients, 725 (65.1%) had good adherence to antihypertensive agents. Binary logistic regression analysis was conducted. Younger age, shorter duration of antihypertensive agents used, job status being employed, and poor or very poor self-perceived health status were negatively associated with drug adherence.<p></p> <b>Conclusion</b> This study reported a high proportion of poor medication adherence among hypertensive subjects. Patients with factors associated with poor adherence should be more closely monitored to optimize their drug taking behavior