Non-vitamin K oral anticoagulants versus warfarin for the treatment of left ventricular thrombus.

INTRODUCTION: Left ventricular thrombus (LVT) is associated with significant morbidity and mortality. Conventional treatment comprises warfarin-mediated anticoagulation; it is unclear whether non-vitamin K oral anticoagulants (NOACs) exhibit comparable efficacy and safety. Limited data are available for Asian patients. This study compared NOACs with warfarin in terms of clinical efficacy and safety for managing LVT. METHODS: Clinical and echocardiographic records were retrieved for all adult patients with echocardiography-confirmed LVT at a major regional centre in Hong Kong from January 2011 to January 2020. Discontinuation of anticoagulation by 1 year was recorded. Outcomes were compared between patients receiving NOACs and those receiving warfarin. Primary outcomes were cumulative mortality and net adverse clinical events (NACEs). Secondary outcomes were complete LVT resolution and percentage reduction in LVT size at 3 months. RESULTS: Forty-three patients were included; 28 received warfarin and 15 received NOACs, with follow-up periods (mean ± standard deviation) of 20 ± 12 months and 22 ± 9 months, respectively (P=0.522). Use of NOACs was associated with significantly lower NACE risk (hazard ratio [HR]=0.111, 95% confidence interval [CI]=0.012-0.994; P=0.049) and a tendency towards lower cumulative mortality (HR=0.184, 95% CI=0.032-1.059; P=0.058). There were no significant differences in secondary outcomes. Considering LVT resolution, discontinuation of anticoagulation by 1 year was not significantly associated with different outcomes. CONCLUSION: Non-vitamin K oral anticoagulants may be an efficacious and safe alternative to warfarin for LVT management. Future studies should explore the safety and efficacy of anticoagulation discontinuation by 1 year as an overall strategy.

Sustaining aviation workforce after the pandemic: Evidence from Hong Kong aviation students toward skills, specialised training, and career prospects through a mixed-method approach.

The aviation industry is in a recession with the rapid and immense outbreak of COVID-19 under globalisation. The future young aviation professionals might suffer from a 'career shock'. This study analysed the post-pandemic career prospects for Hong Kong aviation students using mixed-method research considering specialised and licensed training. We conducted a survey (N = 101) and focus group interviews (N = 6) to investigate students' perceived impediments and potential support from the institutions. Matt-Whitney U test is used to compare the perceptual difference in the impediments, career prospects, skills required, and institutional supports between (non-)specialised training students, (non-)engineering-related students, and (non-)final-year students. The results demonstrated no significant difference between students with and without specialised training. While final-year students perceive themselves as lacking more in terms of non-technical skills than non-final-year students, students are interested in broadening their career options to include airline operations, aircraft engineering and maintenance via acquiring a variety of emerging knowledge and technical skills. Given most studies focus on the recovery pattern of the aviation industry, this study is original in considering Hong Kong aviation students' career impediments and prospects using a mixed-method approach to provide policy insights.

SARS-CoV-2 viral RNA load dynamics in the nasopharynx of infected children.

It is important to understand the temporal trend of the paediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load to estimate the transmission potential of children in schools and communities. We determined the differences in SARS-CoV-2 viral load dynamics between nasopharyngeal samples of infected asymptomatic and symptomatic children. Serial cycle threshold values of SARS-CoV-2 from the nasopharynx of a cohort of infected children were collected for analysis. Among 17 infected children, 10 (58.8%) were symptomatic. Symptomatic children, when compared to asymptomatic children, had higher viral loads (mean cycle threshold on day 7 of illness 28.6 vs. 36.7, P = 0.02). Peak SARS-CoV-2 viral loads occurred around day 2 of illness in infected children. Although we were unable to directly demonstrate infectivity, the detection of significant amount of virus in the upper airway of asymptomatic children suggest that they have the potential to shed and transmit SARS-CoV-2. Our study highlights the importance of contact tracing and screening for SARS-CoV-2 in children with epidemiological risk factors regardless of their symptom status, in order to improve containment of the virus in the community, including educational settings.

Echocardiography update for primary care physicians: a review.

Echocardiography is a key evaluation tool for the diagnosis, prognosis, and guidance of interventional management of numerous cardiovascular conditions, including ischaemia, heart failure, and structural heart diseases. Recent technological advancements have also seen the exploration of artificial intelligence, intracardiac vortex imaging, and three-dimensional printing in echocardiography. With cardiovascular diseases increasing in prevalence worldwide, it is important for clinicians including general practitioners to have updated knowledge of appropriate use of echocardiography. As such, this article reviews the current literature and summarises the latest developments and the general clinical usage of echocardiography.

3D-Printing and Machine Learning Control of Soft Ionic Polymer-Metal Composite Actuators.

This paper presents a new manufacturing and control paradigm for developing soft ionic polymer-metal composite (IPMC) actuators for soft robotics applications. First, an additive manufacturing method that exploits the fused-filament (3D printing) process is described to overcome challenges with existing methods of creating custom-shaped IPMC actuators. By working with ionomeric precursor material, the 3D-printing process enables the creation of 3D monolithic IPMC devices where ultimately integrated sensors and actuators can be achieved. Second, Bayesian optimization is used as a learning-based control approach to help mitigate complex time-varying dynamic effects in 3D-printed actuators. This approach overcomes the challenges with existing methods where complex models or continuous sensor feedback are needed. The manufacturing and control paradigm is applied to create and control the behavior of example actuators, and subsequently the actuator components are combined to create an example modular reconfigurable IPMC soft crawling robot to demonstrate feasibility. Two hypotheses related to the effectiveness of the machine-learning process are tested. Results show enhancement of actuator performance through machine learning, and the proof-of-concepts can be leveraged for continued advancement of more complex IPMC devices. Emerging challenges are also highlighted.

Bell's palsy in children: Current treatment patterns in Australia and New Zealand. A PREDICT study.

AIM: The aetiology and clinical course of Bell's palsy may be different in paediatric and adult patients. There is no randomised placebo controlled trial (RCT) to show effectiveness of prednisolone for Bell's palsy in children. The aim of the study was to assess current practice in paediatric Bell's palsy in Australia and New Zealand Emergency Departments (ED) and determine the feasibility of conducting a multicentre RCT within the Paediatric Research in Emergency Departments International Collaborative (PREDICT). METHODS: A retrospective analysis of ED medical records of children less than 18 years diagnosed with Bell's palsy between 1 January, 2012 and 31 December, 2013 was performed. Potential participants were identified from ED information systems using Bell's palsy related search terms. Repeat presentations during the same illness were excluded but relapses were not. Data on presentation, diagnosis and management were entered into an online data base (REDCap). RESULTS: Three hundred and twenty-three presentations were included from 14 PREDICT sites. Mean age at presentation was 9.0 (SD 5.0) years with 184 (57.0%) females. Most (238, 73.7%) presented to ED within 72 h of symptoms, 168 (52.0%) had seen a doctor prior. In ED, 218 (67.5%) were treated with steroids. Prednisolone was usually prescribed for 9 days at around 1 mg/kg/day, with tapering in 35.7%. CONCLUSION: Treatment of Bell's palsy in children presenting to Australasian EDs is varied. Prednisolone is commonly used in Australasian EDs, despite lack of high-level paediatric evidence. The study findings confirm the feasibility of an RCT of prednisolone for Bell's palsy in children.

Different porcine reproductive and respiratory syndrome (PRRS) vaccine regimes and its effect on pig immunity status at Southeast Asia pig farms.

Porcine reproductive and respiratory syndrome (PRRS) is a disease characterised by late-term reproductive failure in sows and gilts, and respiratory problems in piglets and growing pigs. In this study, 240 sera were collected from four farms that had been practicing different PRRS vaccination regime for more than a year and vaccinations were done at 2 months before sampling. Fifteen sera samples from four age groups: sows, growers, weaners and piglets were collected from each farm and analysed using IDEXX PRRS X3 ELISA for PRRSV antibodies. Pooled serum samples were tested by using nested-PCR that enable the differentiation of Type I and Type II PRRSV. Out of 80 pooled serum samples, none were positive for PRRSV indicating all age groups were not viraemic after vaccination. Results by ELISA test showed all the farms were seropositive for PRRS. ELISA testing showed no significant difference between the farms except for Farm B which practised whole herd US MLV vaccination. Farm B showed significantly lower (p<0.05) S/P ratio in their piglet, grower and sow groups which suggest there was low virus circulation in herd. Farm A which practised US MLV on sow was the only farm found to have seronegative status in their weaners. Data indicates PRRS MLV vaccination will not cause viraemia post four weeks vaccination and whole herd MLV vaccination may help to reduce virus circulation in PRRS endemic farm.

Sensitivity and specificity of the AdenoPlus point-of-care system in detecting adenovirus in conjunctivitis patients at an ophthalmic emergency department: a diagnostic accuracy study.

BACKGROUND: To estimate the diagnostic accuracy (sensitivity and specificity) of the AdenoPlus point-of-care adenoviral test compared to PCR in an ophthalmic accident and emergency service. These findings were compared with those of a previous study. METHODS: This was a prospective diagnostic accuracy study on 121 patients presenting to an emergency eye unit with a clinical picture of acute adenoviral conjunctivitis. AdenoPlus testing was carried out on one eye of each patient and a PCR analysis was also performed on a swab taken from the same eye. AdenoPlus and PCR results were interpreted by masked personnel. Sensitivity and specificity for the AdenoPlus test were calculated using PCR results as the reference standard. RESULTS: 121 patients were enrolled and 109 met the inclusion criteria. 43 patients (39.4%) tested positive for adenovirus by PCR analysis. The sensitivity of the AdenoPlus swab in detecting adenovirus was 39.5% (17/43, 95% CI 26% to 54%) and specificity was 95.5% (63/66, 95% CI 87% to 98%) compared to PCR. CONCLUSIONS: The AdenoPlus test has a high specificity for diagnosing adenoviral conjunctivitis, but in this clinical setting, we could not reproduce the high sensitivity that has been previously published.

Nanothorn electrodes for ionic polymer-metal composite artificial muscles.

Ionic polymer-metal composites (IPMCs) have recently received tremendous interest as soft biomimetic actuators and sensors in various bioengineering and human affinity applications, such as artificial muscles and actuators, aquatic propulsors, robotic end-effectors, and active catheters. Main challenges in developing biomimetic actuators are the attainment of high strain and actuation force at low operating voltage. Here we first report a nanostructured electrode surface design for IPMC comprising platinum nanothorn assemblies with multiple sharp tips. The newly developed actuator with the nanostructured electrodes shows a new way to achieve highly enhanced electromechanical performance over existing flat-surfaced electrodes. We demonstrate that the formation and growth of the nanothorn assemblies at the electrode interface lead to a dramatic improvement (3- to 5-fold increase) in both actuation range and blocking force at low driving voltage (1-3 V). These advances are related to the highly capacitive properties of nanothorn assemblies, increasing significantly the charge transport during the actuation process.

Molecular and phenotypic characterization of multidrug-resistant Mycobacterium tuberculosis isolates resistant to kanamycin, amikacin, and capreomycin in China.

Although second-line anti-tuberculosis (TB) injectable drugs have been widely used to improve treatment outcomes of multidrug-resistant TB (MDR-TB), little is known about the prevalence and mechanism of second-line injectable drug resistance among MDR Mycobacterium tuberculosis isolates in China. Here, we found that 12.7 % (20/158) of isolates showed resistance to at least one second-line injectable drug among 158 MDR isolates. At the same time, there were 16 (10.1 %) strains resistant to kanamycin (KAN), 9 (5.7 %) to amikacin (AMK), and 12 (7.6 %) to capreomycin (CAP). In addition, our data revealed no significant difference in the drug resistance patterns for Beijing versus non-Beijing genotype strains (p > 0.05). The most frequently observed mutation was A-to-G substitution at position 1401 of the rrs gene, conferring high-level resistance to KAN and AMK, but had varying minimum inhibitory concentrations (MICs) for CAP. The mutations in the eis promoter and tlyA gene were responsible for low-level resistance to CAP. 83.3 % of A1401G substitutions in the rrs gene was observed in Beijing genotype strains, while the difference was not significant (p = 0.157). Our data demonstrated that the hot-spot regions localized in the rrs gene serve as excellent markers for AMK, but is not a sensitive marker for KAN and CAP. In addition, the cross-resistance patterns and MICs differed among different genetic mutation types, which challenge the practice in China of generalizing resistance to AMK and CAP based on the resistance to KAN alone. Our findings suggested that the individualized drug susceptibility to three major second-line injectable drugs is essential in order to generate more effective treatment regimens for MDR patients.

Range-based control of dual-stage nanopositioning systems.

A novel dual-stage nanopositioner control framework is presented that considers range constraints. Dual-stage nanopositioners are becoming increasingly popular in applications such as scanning probe microscopy due to their unique ability to achieve long-range and high-speed operation. The proposed control approach addresses the issue that some precision positioning trajectories are not achievable through existing control schemes. Specifically, short-range, low-speed inputs are typically diverted to the long-range actuator, which coincidentally has lower positioning resolution. This approach then limits the dual-stage nanopositioner's ability to achieve the required positioning resolution that is needed in applications where range and frequency are not inversely correlated (which is a typical, but not always the correct assumption for dual stage systems). The proposed range-based control approach is proposed to overcome the limitations of existing control methods. Experimental results show that the proposed control strategy is effective.

Use of the INNO-LIA syphilis score assay in the resolution of discordant positive screening enzyme immunoassay results for the serological diagnosis of syphilis.

We studied the use of the INNO-LIA syphilis score assay in the resolution of discordant positive screening results of the Murex ICE Syphilis enzyme immunoassay (EIA) with the confirmatory results of both the Serodia Treponema pallidum particle agglutination (TPPA) and the fluorescent treponemal antibody-absorption (FTA-Abs) assays, for the serological diagnosis of syphilis. This was an observational study on the serum samples received by the Syphilis Laboratory, Hong Kong, during the period from January 2006 to December 2012. A total of 801 serum samples with discordant positive screening EIA results were used. Consensus results of such serum samples were derived from results of the EIA, TPPA and FTA-abs assays. The age range of the individuals was 14 to 104 years (median of 52). There were 369 males and 432 females. Of 378 serum samples, 139 showed agreement among positive results, 23 of 310 showed agreement among indeterminate results and 277 of 465 showed agreement among negative results. The proportions of agreement among positive, indeterminate and negative results were 0.37 (95% CI 0.32-0.42), 0.07 (95% CI 0.05-0.11) and 0.60 (95% CI 0.55-0.64), respectively; kappa 0.55 (95% CI 0.49-0.60). There were 60 serum samples with positive consensus results but negative INNO-LIA syphilis score results and 10 with negative consensus results but positive INNO-LIA syphilis score results. Although the INNO-LIA syphilis score assay can be considered a valid alternative confirmatory test for the serological diagnosis of syphilis, the present study showed that its use in the resolution of discordant positive screening EIA results was moderate. A more extensive characterization of serum samples with discordant reactive screening treponemal test results is necessary.

First proficiency testing of second-line anti-tuberculosis drug susceptibility testing in 12 provinces of China.

OBJECTIVE: To evaluate the performance of drug susceptibility testing (DST) against the main second-line (SL) anti-tuberculosis drugs in tuberculosis (TB) laboratories in China. METHOD: The supranational TB reference laboratory issued 30 Mycobacterium tuberculosis isolates to the participating laboratories. Each participating laboratory performed DST against kanamycin (KM), amikacin (AMK), capreomycin (CPM) and ofloxacin (OFX) using the proportion method in Löwenstein-Jensen medium per World Health Organization recommendations. Reported results were checked and compared with the judicial results. RESULT: The main performance indicators for the four anti-tuberculosis drugs evaluated (KM, AMK, CPM, OFX) were as follows: accordance rates: 91.62%, 99.16%, 96.93% and 96.37%; reproducibility: 99.16%, 99.16%, 94.96% and 94.12%; specificity: 99.12%, 99.64%, 98.00% and 98.41%; sensitivity: 78.03%, 97.62%, 94.44% and 91.51%. The accordance rates and sensitivity values of the four drugs showed statistically significant differences, while specificities showed no significant differences. CONCLUSION: Eight (66.7%) participating laboratories met the set requirement criteria; however, DST in four (33.3%) laboratories requires greater attention. Of the four drugs tested, the results for KM were lower than those for the other drugs. External quality assessment can lead to effective evaluation of laboratory performance in SL DST.

A pilot external quality assurance programme for line-probe assay detection of anti-tuberculosis drug resistance.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB; resistance to isoniazid and rifampicin) is difficult to detect and control. Line-probe assays (LiPA) are widely used for the rapid detection of MDR-TB. OBJECTIVE: To ensure the quality of the test, a pilot external quality assurance (EQA) programme was initiated to assess the feasibility of running such a programme and the possibility of improving the proficiency of TB laboratories in performing the test. DESIGN: Prepared filter-paper-based Mycobacterium tuberculosis DNA samples were shipped to participant laboratories for LiPA EQA. The tests were performed blind, and the results were returned to the organising laboratory for comparison and analysis. RESULTS: A total of four rounds of EQA samples were dispatched to five laboratories in four countries. Overall inter- and intra-laboratory reproducibility was respectively 97% and 96%. The strengths and weaknesses of the participant laboratories in performing the test were discussed. CONCLUSION: A LiPA EQA programme can ensure quality and improve the performance of TB laboratories. This is a critical step during the initial stages at the time of setting up this method of testing.

Multicentre evaluation of Ziehl-Neelsen and light-emitting diode fluorescence microscopy in China.

OBJECTIVE: To assess the feasibility of using light-emitting diode fluorescence microscopy (LED-FM) in peripheral laboratories in China. DESIGN: The performance of LED-FM and Ziehl-Neelsen (ZN) microscopy was compared on slides directly prepared from the sputum of tuberculosis (TB) suspects and follow-up patients on treatment. The examination time, fading of fluorescence-stained slides, average unit cost and qualitative user appraisal of LED-FM were also analysed. RESULTS: Among 11 276 slides, the smear-positive rate for LED-FM was 11.2% (1263/11 276), 2.6% (294/11 276) higher than that of ZN (8.6%, 969/11 276; χ(2) 263.5, P < 0.05). The examination time for LED-FM (120.0 ± 38.9 seconds) was shorter than that for ZN (206.3 ± 75.9 s; t = 28.12, P < 0.05). For smear fading, quantitative and qualitative errors occurred within respectively 7.8 and 7.7 weeks. The average unit costs for ZN and LED-FM were respectively US$2.20 ± 0.58 and US$1.97 ± 0.71 (t = 5.08, P < 0.05). LED-FM was accepted by most laboratory technicians. CONCLUSION: LED-FM compared favourably with ZN, with a higher smear-positive detection rate, a shorter examination time and lower unit examination cost. LED-FM may be an alternative to ZN as a cost-effective method for detecting bacilli in peripheral laboratories in China.