205 research outputs found

    Chaotic Phenomena and Nonlinear Responses in a Vibroacoustic System

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    A Prospective Study of Venous Thromboembolic Prophylaxis Using Foot Pumps Following Total Knee Replacement in a Chinese Population

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    AbstractPurposeThe purpose of this study was to evaluate foot pumps as mechanical prophylaxis for deep vein thrombosis (DVT) following total knee replacement (TKR) in a Chinese population.MethodsAll consecutive patients following TKR during 2002–2006 received routine duplex ultrasound surveillance for DVT 9 days postoperatively. The demographic data and risk factors were recorded. No medication was given for DVT prophylaxis in all patients.ResultsWe evaluated 91 consecutive TKRs in 85 patients. Although 44 knee replacements (Group 1) done before December 2004 were not given foot pumps, 47 knee replacements (Group 2) done afterwards were given foot pumps. All patients were followed up for more than 6 months. DVT was detected in three cases (6.8%) in Group 1 compared with four knees (8.5%) in Group 2. Proximal thrombosis was observed in two knees (4.5%) in Group 1 compared with two knees (4.3%) in Group 2. No patient had pulmonary embolism. Six out of 59 (10.2%) patients who underwent the operations under general anaesthesia suffered from DVT, whereas one in 28 (3.6%) patients operated under spinal anaesthesia had DVT. All had no statistical significance.ConclusionThe rate of proximal DVT after TKR was low (4.5%) without pharmacological prophylaxis. We advise against the use of pharmacological prophylaxis in Chinese population for TKRs because of the low risk of proximal DVT and its possible bleeding complications. Foot pump did not lower the rate of DVTfurther, and its use for DVT prophylaxis in TKR is not necessary

    An Algorithm for Modelling Escalator Fixed Loss Energy for PHM and sustainable energy usage

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    Prognostic Health Management (PHM) is designed to assess and monitor the health status of systems, anticipate the onset of potential failure, and prevent unplanned downtime. In recent decades, collecting massive amounts of real-time sensor data enabled condition monitoring (CM) and consequently, detection of abnormalities to support maintenance decision-making. Additionally, the utilization of PHM techniques can support energy sustainability efforts by optimizing energy usage and identifying opportunities for energy-saving measures. Escalators are efficient machines for transporting people and goods, and measuring energy consumption in time can facilitate PHM of escalators. Fixed loss energy, or no-load energy, of escalators denotes the energy consumption by an unloaded escalator. Fixed loss energy varies over time indicating varying operating conditions. In this paper, we propose to use escalators' fixed loss energy for PHM. We propose an approach to compute daily fixed loss energy based on energy consumption sensor data. The proposed approach is validated using a set of experimental data. The advantages and disadvantages of each approach are also presented, and recommendations are given. Finally, to illustrate PHM, we set up an EWMA chart for monitoring the fixed loss over time and demonstrate the potential in reducing energy costs associated with escalator operation

    Remaining Useful Life Modelling with an Escalator Health Condition Analytic System

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    The refurbishment of an escalator is usually linked with its design life as recommended by the manufacturer. However, the actual useful life of an escalator should be determined by its operating condition which is affected by the runtime, workload, maintenance quality, vibration, etc., rather than age only. The objective of this project is to develop a comprehensive health condition analytic system for escalators to support refurbishment decisions. The analytic system consists of four parts: 1) online data gathering and processing; 2) a dashboard for condition monitoring; 3) a health index model; and 4) remaining useful life prediction. The results can be used for a) predicting the remaining useful life of the escalators, in order to support asset replacement planning and b) monitoring the real-time condition of escalators; including alerts when vibration exceeds the threshold and signal diagnosis, giving an indication of possible root cause (components) of the alert signal.Comment: 14 pages, 12 figures, 7 table

    Hong Kong dentists' preparedness for medical emergency in dental clinics

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    Aim: The aim of this study was to investigate the Hong Kong dentists’ and dental clinics’ preparedness for medical emergency in the dental clinic. Methods: Two custom designed questionnaires were developed, one for dentists and another for dental clinics, to collect the required information. The sampling frame for participants was the list of registered dentists published by the Hong Kong Dental Council on its website in January 2016. A total of 434 dentists and 143 dental clinics were selected from the list by systematic random sampling. The latter sample was supplemented by 10 randomly selected government dental clinics. The questionnaires were mailed the selected dentists together with a cover letter and a stamped return envelope. A reminder letter and another copy of the questionnaire were sent out two weeks after the first mailing. Results: 167 (38%) completed dentist questionnaires and 53 (35%) clinic questionnaires were collected. Most of the respondent dentists had some deficient knowledge on basic life support (BLS), their mean score was 3.5 out of a maximum of 5. Most (>60%) of the respondents thought they were competent in performing medical emergency procedures except giving intravenous injection. Moreover, most (>60%) of them held positive attitude towards having immediate availability of essential medical emergency equipment and drugs in their clinic. Dentists who were more recent graduates, those with postgraduate qualifications, and those who work with accompaniment generally had higher mean BLS knowledge scores. In the dental clinics, the most commonly kept medical emergency equipment/drug was instant glucose (70%) and followed by antihistamine (62%). Only a quarter of the clinics were equipped with AED, and 45% were equipped with oxygen cylinder. For 8 out of the 11 items, a higher proportion of the bigger clinics (>2 dental chairs) than the smaller clinics had the medical emergency equipment/drug available (Chi-square test, p<0.05). Conclusion: Hong Kong dentists have a moderate level of knowledge on BLS which should be enhanced through regular attendance at CE courses. Their knowledge level is affected by a number of their background and professional activities factors. Most dental clinics in Hong Kong have only few of the essential medical emergency equipment and drugs while the larger clinics are better equipped than the smaller clinics.published_or_final_versio

    Coronavirus-positive Nasopharyngeal Aspirate as Predictor for Severe Acute Respiratory Syndrome Mortality

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    Severe acute respiratory syndrome (SARS) has caused a major epidemic worldwide. A novel coronavirus is deemed to be the causative agent. Early diagnosis can be made with reverse transcriptase-polymerase chain reaction (RT-PCR) of nasopharyngeal aspirate samples. We compared symptoms of 156 SARS-positive and 62 SARS-negative patients in Hong Kong; SARS was confirmed by RT-PCR. The RT-PCR–positive patients had significantly more shortness of breath, a lower lymphocyte count, and a lower lactate dehydrogenase level; they were also more likely to have bilateral and multifocal chest radiograph involvement, to be admitted to intensive care, to need mechanical ventilation, and to have higher mortality rates. By multivariate analysis, positive RT-PCR on nasopharyngeal aspirate samples was an independent predictor of death within 30 days

    Examining consumers’ adoption of wearable healthcare technology: The role of health attributes

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    With the advancement of information technology, wearable healthcare technology has emerged as one of the promising technologies to improve the wellbeing of individuals. However, the adoption of wearable healthcare technology has lagged when compared to other well-established durable technology products, such as smartphones and tablets, because of the inadequate knowledge of the antecedents of adoption intention. The aim of this paper is to address an identified gap in the literature by empirically testing a theoretical model for examining the impact of consumers’ health beliefs, health information accuracy, and the privacy protection of wearable healthcare technology on perceived usefulness. Importantly, this study also examines the influences of perceived usefulness, consumer innovativeness, and reference group influence on the adoption intention of wearable healthcare technology. The model seeks to enhance understanding of the influential factors in adopting wearable healthcare technology. Finally, suggestions for future research for the empirical investigation of the model are provided

    Handgrip strength assessment at baseline in addition to bone parameters could potentially predict the risk of curve progression in adolescent idiopathic scoliosis

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    IntroductionAdolescent idiopathic scoliosis (AIS) is characterized by deranged bone and muscle qualities, which are important prognostic factors for curve progression. This retrospective case–control study aims to investigate whether the baseline muscle parameters, in addition to the bone parameters, could predict curve progression in AIS.MethodsThe study included a cohort of 126 female patients diagnosed with AIS who were between the ages of 12 and 14 years old at their initial clinical visit. These patients were longitudinally followed up every 6 months (average 4.08 years) until they reached skeletal maturity. The records of these patients were thoroughly reviewed as part of the study. The participants were categorized into two sub-groups: the progressive AIS group (increase in Cobb angle of ≥6°) and the stable AIS group (increase in Cobb angle &lt;6°). Clinical and radiological assessments were conducted on each group.ResultsCobb angle increase of ≥6° was observed in 44 AIS patients (34.9%) prior to skeletal maturity. A progressive AIS was associated with decreased skeletal maturity and weight, lower trunk lean mass (5.7%, p = 0.027) and arm lean mass (8.9%, p &lt; 0.050), weaker dominant handgrip strength (8.8%, p = 0.027), deranged cortical compartment [lower volumetric bone mineral density (vBMD) by 6.5%, p = 0.002], and lower bone mechanical properties [stiffness and estimated failure load lowered by 13.2% (p = 0.005) and 12.5% (p = 0.004)]. The best cut-off threshold of maximum dominant handgrip strength is 19.75 kg for distinguishing progressive AIS from stable AIS (75% sensitivity and 52.4% specificity, p = 0.011).DiscussionPatients with progressive AIS had poorer muscle and bone parameters than patients with stable AIS. The implementation of a cut-off threshold in the baseline dominant handgrip strength could potentially be used as an additional predictor, in addition to bone parameters, for identifying individuals with AIS who are at higher risk of experiencing curve progression

    MicroRNA clusters integrate evolutionary constraints on expression and target affinities : the miR-6/5/4/286/3/309 cluster in Drosophila

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    This research was supported by the Hong Kong Research Grant Council GRF Grant (14103516), The Chinese University of Hong Kong Direct Grant (4053248), and TUYF Charitable Trust (6903957) (JHLH).A striking feature of microRNAs is that they are often clustered in the genomes of animals. The functional and evolutionary consequences of this clustering remain obscure. Here, we investigated a microRNA cluster miR-6/5/4/286/3/309 that is conserved across drosophilid lineages. Small RNA sequencing revealed expression of this microRNA cluster in Drosophila melanogaster leg discs, and conditional overexpression of the whole cluster resulted in leg appendage shortening. Transgenic overexpression lines expressing different combinations of microRNA cluster members were also constructed. Expression of individual microRNAs from the cluster resulted in a normal wild-type phenotype, but either the expression of several ancient microRNAs together (miR-5/4/286/3/309) or more recently evolved clustered microRNAs (miR-6-1/2/3) can recapitulate the phenotypes generated by the whole-cluster overexpression. Screening of transgenic fly lines revealed down-regulation of leg patterning gene cassettes in generation of the leg-shortening phenotype. Furthermore, cell transfection with different combinations of microRNA cluster members revealed a suite of downstream genes targeted by all cluster members, as well as complements of targets that are unique for distinct microRNAs. Considered together, the microRNA targets and the evolutionary ages of each microRNA in the cluster demonstrates the importance of microRNA clustering, where new members can reinforce and modify the selection forces on both the cluster regulation and the gene regulatory network of existing microRNAs.PostprintPeer reviewe

    Political Strategy and the Growth of Business Groups

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    How do companies and government interactions affect business groups’ decisions on growth? So far, empirical evidence is based on qualitative data that do not explain how political strategies affect the expansion or diversification of business groups. Our main contribution is to discuss the conditions that affect their growth. To do this, we conducted an in-depth field study in six business groups, and examined 17 growth decisions. Four categories (origin of growth, historical relationships, business group’s scope and use of specific political strategies) emerged from the analysis, based on interviews with managers and on 480 secondary data sources. We further applied the qualitative comparative method to test our categories as conditions for growth. We found that a historical relationship between the group and the government is a necessary but insufficient condition for growth through diversification. To foresee diversification, historical relationship must be aligned with government’s political interest, or with the use of one or a combination of specific political tactics. We found no set of variables that can fully explain growth through expansion
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