Study of thermal bubble motion in microchannel

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.The micro capillary pumped loop system (MCPL) is a highly efficient device for heat transfer because the main driving force is a result of thermo-bubbles in micro-channel. In this study, the scaling effect with respect to the dimensional geometry of MCPL was studied for improving the heat transfer performance. The results showed that when a larger heating power was provided by microheater, the growing rate of thermal bubble was faster. Generally speaking, injecting a larger amount of working fluids resulted in faster thermo bubble motion. When the size of channel was scaled down, the nucleation of thermal bubble occurred easily and a positive performance of heat transfer was expected. These findings will be useful to the further optimal design of MCPL.This study is funded by the National Science Council of the Republic of China, Taiwan, under Contract No. NSC- 98-2221-E-197 –018

Sequence Variations of Full-Length Hepatitis B Virus Genomes in Chinese Patients with HBsAg-Negative Hepatitis B Infection

BACKGROUND: The underlying mechanism of HBsAg-negative hepatitis B virus (HBV) infection is notoriously difficult to elucidate because of the extremely low DNA levels which define the condition. We used a highly efficient amplification method to overcome this obstacle and achieved our aim which was to identify specific mutations or sequence variations associated with this entity. METHODS: A total of 185 sera and 60 liver biopsies from HBsAg-negative, HBV DNA-positive subjects or known chronic hepatitis B (CHB) subjects with HBsAg seroclearance were amplified by rolling circle amplification followed by full-length HBV genome sequencing. Eleven HBsAg-positive CHB subjects were included as controls. The effects of pivotal mutations identified on regulatory regions on promoter activities were analyzed. RESULTS: 22 and 11 full-length HBV genomes were amplified from HBsAg-negative and control subjects respectively. HBV genotype C was the dominant strain. A higher mutation frequency was observed in HBsAg-negative subjects than controls, irrespective of genotype. The nucleotide diversity over the entire HBV genome was significantly higher in HBsAg-negative subjects compared with controls (p = 0.008) and compared with 49 reference sequences from CHB patients (p = 0.025). In addition, HBsAg-negative subjects had significantly higher amino acid substitutions in the four viral genes than controls (all p<0.001). Many mutations were uniquely found in HBsAg-negative subjects, including deletions in promoter regions (13.6%), abolishment of pre-S2/S start codon (18.2%), disruption of pre-S2/S mRNA splicing site (4.5%), nucleotide duplications (9.1%), and missense mutations in "alpha" determinant region, contributing to defects in HBsAg production. CONCLUSIONS: These data suggest an accumulation of multiple mutations constraining viral transcriptional activities contribute to HBsAg-negativity in HBV infection.published_or_final_versio

Progenitor-like cells derived from mouse kidney protect against renal fibrosis in a remnant kidney model via decreased endothelial mesenchymal transition

Showing A quantification of GFP-positive cells in the lung after intravenous injection of MKPCs in five-sixths nephrectomized mice (y axis shows the number of cells, while the x axis (FL1-H) shows the fluorescence intensity; M1 is the area of GFP-positive cells) and B immunohistochemistry of the lung after intravenous injection of MKPCs into a mouse that underwent five-sixths nephrectomy. Few GFP positive cells were found in the lung at the first day but there were no GFP-positive cells at week 14. (TIFF 2253 kb

C-Explorer: Browsing Communities in Large Graphs

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ω-3 fatty acids, γ-linolenic acid, and antioxidants: immunomodulators or inert dietary supplements?

Citation: Rice TW, Wheeler AP, Thompson BT, deBoisblanc BP, Steingrub J, Rock, P. Enteral Omega-3 Fatty Acid, γ-Linolenic Acid, and Antioxidant Supplementation in Acute Lung Injury. JAMA. 2011; 306(14):1574-1581. PubMed PMID: 21976613.Background: The omega-3 (n-3) fatty acids docosahexaenoic acid and eicosapentaenoic acid, along with γ-linolenic acid and antioxidants, may modulate systemic inflammatory response and improve oxygenation and outcomes in patients with acute lung injury.Methods: Objective: To determine if dietary supplementation of these substances to patients with acute lung injury would increase ventilator-free days to study day 28.Design: The OMEGA study, a randomized, double-blind, placebo-controlled, multicenter trial conducted from January 2, 2008, through February 21, 2009. All participants had complete follow-up.Setting: This trial occurred at 44 hospitals in the National Heart, Lung, and Blood Institute ARDS Clinical Trials Network.Subjects: Participants were 272 adults within 48 hours of developing acute lung injury requiring mechanical ventilation whose physicians intended to start enteral nutrition.Intervention: Twice-daily enteral supplementation of n-3 fatty acids, γ -linolenic acid, and antioxidants compared with an isocaloric control. Enteral nutrition, directed by a protocol, was delivered separately from the study supplement.Outcomes: Ventilator-free days to study day 28.Results: The study was stopped early for futility after 143 and 129 patients were enrolled in the n-3 and control groups. Despite an 8-fold increase in plasma eicosapentaenoic acid levels, patients receiving the n-3 supplement had fewer ventilator-free days (14.0 vs 17.2; P=.02) (difference, -3.2 [95% CI, -5.8 to -0.7]) and intensive care unit-free days (14.0 vs 16.7; P=.04). Patients in the n-3 group also had fewer nonpulmonary organ failure-free days (12.3 vs 15.5; P=.02). Sixty-day hospital mortality was 26.6% in the n 3 group vs 16.3% in the control group (P=.054), and adjusted 60-day mortality was 25.1% and 17.6% in the n-3 and control groups, respectively (P=.11). Use of the n-3 supplement resulted in more days with diarrhea (29% vs 21%; P=.001).Conclusions: Twice-daily enteral supplementation of n-3 fatty acids, γ-linolenic acid, and antioxidants did not improve the primary end point of ventilator-free days or other clinical outcomes in patients with acute lung injury and may be harmful. © 2012 BioMed Central Ltd

Reform of copyright law in Hong Kong: time to redraw the balance

This article reviews the current permitted acts under the Copyright Ordinance and their implications for Hong Kong. The discussion focuses on those permitted acts having a direct impact on two sectors the Hong Kong Government is most concerned with: education and the software industry. It shows that because of the limitations of the permitted acts, the Copyright Ordinance has failed to strike the right balance between the conflicting interests in these two sectors; rather, it favours the copyright owners. The article traces the cause of the imbalance to three main deficiencies in the Copyright Ordinance and proposes a solution to strike the right balance.published_or_final_versio

Consensus statement on ischaemic stroke care in Hong Kong

Objective. To issue guidelines for the care of acute stroke in Hong Kong, with the target audience of all health care professionals who are involved in acute stroke care. Participants. The Hong Kong Neurological Society and the Hong Kong Stroke Society. Evidence. The panel applied the 'rule of evidence' used by the United States Agency for Health Care Policy and Research. When there is insufficient evidence, the recommendation was based on customary practice and was circulated among the members and fellows of the two societies before coming to a consensus. Consensus process. Group meetings were held in 2002 to review the literature about acute care for patients with ischaemic stroke and to issue a consensus statement with reference to the local health care system. Participants of the meetings were appointed by the councils of The Hong Kong Neurological Society and the Hong Kong Stroke Society. The draft statement was circulated among the members and fellows of the two societies for comments before it was finalised. Conclusions. Ischaemic stroke is a heavy health care burden to Hong Kong. The current consensus statement provides a framework to establish a multidisciplinary approach towards its acute management.published_or_final_versio

Transient ischaemic attack patients are often underevaluated: Authors' reply

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Developing an EEG-based on-line closed-loop lapse detection and mitigation system

© 2014 Wang, Huang, Wei, Huang, Ko, Lin, Cheng and Jung. In America, 60% of adults reported that they have driven a motor vehicle while feeling drowsy, and at least 15-20% of fatal car accidents are fatigue-related. This study translates previous laboratory-oriented neurophysiological research to design, develop, and test an On-line Closed-loop Lapse Detection and Mitigation (OCLDM) System featuring a mobile wireless dry-sensor EEG headgear and a cell-phone based real-time EEG processing platform. Eleven subjects participated in an event-related lane-keeping task, in which they were instructed to manipulate a randomly deviated, fixed-speed cruising car on a 4-lane highway. This was simulated in a 1st person view with an 8-screen and 8-projector immersive virtual-reality environment. When the subjects experienced lapses or failed to respond to events during the experiment, auditory warning was delivered to rectify the performance decrements. However, the arousing auditory signals were not always effective. The EEG spectra exhibited statistically significant differences between effective and ineffective arousing signals, suggesting that EEG spectra could be used as a countermeasure of the efficacy of arousing signals. In this on-line pilot study, the proposed OCLDM System was able to continuously detect EEG signatures of fatigue, deliver arousing warning to subjects suffering momentary cognitive lapses, and assess the efficacy of the warning in near real-time to rectify cognitive lapses. The on-line testing results of the OCLDM System validated the efficacy of the arousing signals in improving subjects' response times to the subsequent lane-departure events. This study may lead to a practical on-line lapse detection and mitigation system in real-world environments

Granular jet impingement on a fixed target

Author name used in this publication: C. K. Chan2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe