Modeling saturated and unsaturated ferroelectric hysteresis loops : an analytical approach

Author name used in this publication: C. H. TsangAuthor name used in this publication: C. K. WongAuthor name used in this publication: F. G. Shin2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Explicit expressions for the dynamic polarization behavior in ferroelectrics with symmetric/asymmetric electrical conductivity

Author name used in this publication: C. K. WongAuthor name used in this publication: C. H. TsangAuthor name used in this publication: F. G. Shin2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Modeling of bias-field-dependent dielectric properties in ferroelectric thin films

Author name used in this publication: C. K. WongAuthor name used in this publication: C. H. TsangAuthor name used in this publication: F. G. Shin2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Cascading effect in bioprocessing – the impact of mild hypothermia on CHO cell behavior and host cell protein composition

A major challenge in downstream purification of monoclonal antibodies (mAb) is the removal of host cell proteins (HCPs). Previous studies have shown that cell culture decisions significantly impact the HCP content at harvest. However, it is currently unclear how process conditions affect physiological changes in the host cell population, and how these changes, in turn, cascade down to change the HCP profile. We examined how temperature downshift (TDS) to mild hypothermia affects key upstream performance indicators, i.e. antibody titre, HCP concentration and HCP species, across the cell culture decline phase and at harvest through the lens of changes in cellular behaviour. Mild hypothermic conditions introduced on day 5 of fed-batch Chinese hamster ovary (CHO) cell bioreactors resulted in a lower cell proliferation rate but larger percentages of healthier cells across the cell culture decline phase compared to bioreactors maintained at standard physiological temperature. Moreover, the onset of apoptosis was less evident in mild hypothermic cultures. Consequently, mild hypothermic cultures took an extra five days to reach an integral viable cell concentration (IVCC) and antibody yield similar to that of the control at standard physiological temperature. When cell viability dropped below 80%, mild hypothermic cell cultures had a reduced variety of HCP species by 36%, including approximately 44% and 27% lower proteases and chaperones, respectively, despite having similar HCP concentration. This study suggests that TDS may be a good strategy to provide cleaner downstream feedstocks by reducing the variety of HCPs and to maintain product integrity by reducing the number of proteases and chaperones

An ecological analysis of secondary school students' drug use in Hong Kong: A case-control study

Background: Youth drug use is a significant at-risk youth behaviour and remains as one of the top priorities for mental health services, researchers and policy planners. The ecological characteristics of secondary school students’ behaviour in Hong Kong are understudied. Aim: To examine individual, familial, social and environmental correlates of drug use among secondary students in Hong Kong. Method: Data were extracted from a school survey with 3078 students. Among the 3078 students, 86 students reported to have used drugs in the past 6 months. A total of 86 age- and gender-matched controls with no drug-use behaviour in the past 6 months were randomly selected from the remaining students. Multiple logistic analysis was used to examine differential correlates between those who used and did not use substance in the past 6 months. Result: Positive school experience and perspective to school and parental support are protective factors of drug use. Lower self-esteem, lower self-efficacy against using drugs and higher level of permissive attitude towards drugs were associated with drug use. Students who were low in self-esteem and rather impulsive tend to use drugs. Conclusion: To prevent students from drug use, efforts in individual, family, school and community-levels should be addressed.postprin

Simulation of nonlinear dielectric properties of polyvinylidene fluoride based on the Preisach model

Author name used in this publication: C. H. TsangAuthor name used in this publication: F. G. Shin2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Patients' satisfaction and prevalence of complications on surgical extraction of third molar.

OBJECTIVES: To study patients' satisfaction and prevalence of complications in surgical extraction of impacted third molar by senior dentists and recently graduated dentists in a university dental clinic. METHOD: Patients who had impacted third molar extraction in a university dental clinic by two associate dentists who had 15 years of experience were evaluated in this study. Patients' age, sex, history of pericoronitis, tooth extracted, and radiographic assessment of the impacted tooth were recorded. Immediately after suture removal, the patients were invited to indicate their satisfaction on a Likert scale of 1-5. RESULTS: A total of 546 patients received extraction, and 251 patients were operated by associate dentists. Patient satisfaction was higher among those who had noncomplicated surgery (P=0.007), short treatment time (P<0.001), and had no postsurgical emergency appointments (P<0.001). The prevalence of seeking postsurgical emergency appointments was 9.2%. The reasons were severe pain (4.8%), swelling (2.6%), bleeding (2.4%), alveolar osteitis (0.9%), paresthesia (0.9), and trismus (0.5%). The prevalence of postsurgical complication(s) in associate dentists and senior dentists was 11.6% and 7.1%, respectively (P=0.050). The mean satisfaction scores for associate dentists and senior dentists were 4.17 and 3.95, respectively (P=0.002). CONCLUSION: Although a higher rate of postsurgical complications was observed among the patients treated by the recently graduated dentists, their patients' satisfaction scores were higher than that of the senior dentists. Around 9% of patients attended postsurgical emergency appointments, and their common reason was severe pain.published_or_final_versio

Genotypic analysis of Klebsiella pneumoniae isolates in a Beijing hospital reveals high genetic diversity and clonal population structure of drug-resistant isolates.

Background The genetic diversity and the clinical relevance of the drug-resistant Klebsiella pneumoniae isolates from hospital settings are largely unknown. We thus conducted this prospective study to analyze the molecular epidemiology of K. pneumoniae isolates from patients being treated in the 306 Hospital in Beijing, China for the period of November 1, 2010–October 31, 2011. Methodology/Principal Findings Antibiotic susceptibility testing, PCR amplification and sequencing of the drug resistance-associated genes, and multilocus sequence typing (MLST) were conducted. A total of 163 isolates were analyzed. The percentage of MDR, XDR and PDR isolates were 63.8% (104), 20.9 (34), and 1.8% (3), respectively. MLST results showed that 60 sequence types (STs) were identified, which were further separated by eBURST into 13 clonal complexes and 18 singletons. The most dominant ST was ST15 (10.4%). Seven new alleles and 24 new STs were first identified in this study. Multiple logistic regression analysis revealed that certain clinical characteristics were associated with those prevalent STs such as: from ICU, from medical ward, from community acquired infection, from patients without heart disease, from patients with treatment success, susceptible to extended spectrum cephalosporin, susceptible to cephamycins, susceptible to fluoroquinolones, and with MDR. Conclusions/Significance Our data indicate that certain drug-resistant K. pneumoniae clones are highly prevalent and are associated with certain clinical characteristics in hospital settings. Our study provides evidence demonstrating that intensive nosocomial infection control measures are urgently needed.published_or_final_versio

On the elliptical flow in asymmetric collisions and nuclear equation of state

We here present the results of elliptical flow for the collision of different asymmetric nuclei (10Ne20 +13 Al27, 18Ar40 +21 Sc45, 30Zn64 +28 Ni58, 36Kr86 +41 Nb93) by using the Quantum Molecular Dynamics (QMD) model. General features of elliptical flow are investigated with the help of theoretical simulations. The simulations are performed at different beam energies between 40 and 105 MeV/nucleon. A significant change can be seen from in-plane to out-of-plane elliptical flow of different fragments with incident energy. A comparison with experimental data is also made. Further, we predict, for the first time that, elliptical flow for different kind of fragments follow power law dependence ? C(Atot)? for asymmetric systems

Rising to the occasion : disaster social work in China

Author name used in this manuscript: Timothy SIM2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe