Improvements in genomic and molecular methods are expanding the range of potential applications for circulating tumour DNA (ctDNA), both in a research setting and as a 'liquid biopsy' for cancer ...management. Proof-of-principle studies have demonstrated the translational potential of ctDNA for prognostication, molecular profiling and monitoring. The field is now in an exciting transitional period in which ctDNA analysis is beginning to be applied clinically, although there is still much to learn about the biology of cell-free DNA. This is an opportune time to appraise potential approaches to ctDNA analysis, and to consider their applications in personalized oncology and in cancer research.
A novel coronavirus of zoonotic origin (2019-nCoV) has recently been identified in patients with acute respiratory disease. This virus is genetically similar to SARS coronavirus and bat SARS-like ...coronaviruses. The outbreak was initially detected in Wuhan, a major city of China, but has subsequently been detected in other provinces of China. Travel-associated cases have also been reported in a few other countries. Outbreaks in health care workers indicate human-to-human transmission. Molecular tests for rapid detection of this virus are urgently needed for early identification of infected patients.
We developed two 1-step quantitative real-time reverse-transcription PCR assays to detect two different regions (ORF1b and N) of the viral genome. The primer and probe sets were designed to react with this novel coronavirus and its closely related viruses, such as SARS coronavirus. These assays were evaluated using a panel of positive and negative controls. In addition, respiratory specimens from two 2019-nCoV-infected patients were tested.
Using RNA extracted from cells infected by SARS coronavirus as a positive control, these assays were shown to have a dynamic range of at least seven orders of magnitude (2x10-4-2000 TCID50/reaction). Using DNA plasmids as positive standards, the detection limits of these assays were found to be below 10 copies per reaction. All negative control samples were negative in the assays. Samples from two 2019-nCoV-infected patients were positive in the tests.
The established assays can achieve a rapid detection of 2019n-CoV in human samples, thereby allowing early identification of patients.
Unlike the studies of freshmen entrants, the learning experiences of community college transfer (CCT) students in the receiving university is a topic that has only started to gain attention in recent ...decades. Little is known about the differences between CCT and freshmen entrants with regard to their study workload stress and its relationship with their perceptions of the teaching and learning environment, approaches to learning, self-efficacy and generic skills. The purpose of our study was to address this gap. This was a cross-sectional survey study conducted from April 2018 to November 2018 in a university in Hong Kong. The HowULearn questionnaire was adapted to local usage and validated for data collection. In total, 841 CCT students and 978 freshmen entrants completed the survey. The respondents were aged between 19 and 52 years (mean = 21.6, SD = 1.92), and 66.0% were women. The HowULearn questionnaire was determined by factor analyses to have eight factors. The reliabilities of the eight factors were found to be acceptable (Cronbach alphas = 0.709-0.918). The CCT students scored significantly higher than the freshmen entrants for perceived study workload stress and surface approaches to learning, but lower on teaching for understanding & encouraging learning, peer support, and self-efficacy beliefs. The surface approach to learning, deep & organized studying, alignment & constructive feedback, and generic skills were found to be predictors of study workload stress in both groups of students, and in the overall student data. This study has shown that CCT students and freshmen entrants differed with regard to their study workload stress and learning experiences. Our findings provide a message, both for educators in higher education and policy makers in the government-there is not a one-size-fits-all approach to different student populations when it comes to enhancing their learning experiences.
This paper investigates an electricity time-of-use (TOU) tariff problem with the consideration of consumer behavior. Under the TOU tariff, we consider two periods: the peak and base periods. A ...two-level model is established to solve the TOU tariff problem: in the upper level, the producer determines the TOU tariff with the consideration of consumer behavior; in the lower level, the consumers respond to the TOU tariff through shifting some electricity consumption in the peak period to the base period. Using the traditional flat-rate (FR) tariff as a baseline, we verify the conditions under which the producer has incentives to adopt the TOU tariff. With the adoption of a general consumer transfer cost, we solve for the optimal TOU tariff under different situations. Our results demonstrate that proper adoption of the TOU tariff can create a win–win situation for both the producer and the consumers: the producer can increase its profit and the consumers can save their electricity cost. We further evaluate the effectiveness of the TOU tariff in terms of the peak demand reduction. Using a quadratic transfer cost, we obtain some managerial insights into the TOU tariff problem, and illustrate that the TOU tariff is always beneficial to the producer and the consumers under the quadratic transfer cost.
•This paper investigates a new electricity time-of-use (TOU) tariff problem with the consideration of consumer behavior.•We verify the conditions under which the producer has incentives to adopt the TOU tariff.•We solve for the optimal TOU tariff under different situations.•Our results show that proper adoption of the TOU tariff can create a win–win situation.•We obtain some managerial insights into the TOU tariff problem.
Prior cultural research generally agrees that Asian consumers (collectivists), who emphasize social harmony, are less likely to complain but more likely to switch and to spread negative word-of-mouth ...than Western consumers (individualists) in service failures. Drawing from the face concern and embarrassment literature, this paper argues that collectivists are not necessarily less likely to complain than individualists. In fact, the impact of culture on consumer complaining responses will be contingent on the degree of embarrassment involved in the service failure. Results from a cross-cultural experiment indicate that only in a non-embarrassing failure will collectivists less likely complain than individualists. In an embarrassing failure, however, collectivists will more likely complain, as well as switch and spread negative word-of-mouth. These results not only yield interesting insights into cross-cultural consumer behaviors, but also provide rich managerial implications.
► Collectivists (vs. individualists) are not necessarily less likely to complain. ► In embarrassing failure, collectivists (vs. individualists) will more likely complain, switch and spread negative word-of-mouth. ► Face concern is the key explanatory variable for these cultural differences.
Different symmetry breaking ways determine various magnetization switching modes driven by spin-orbit torques (SOT). For instance, an applied or effective field parallel to applied current is ...indispensable to switch magnetization with perpendicular anisotropy by SOT. Besides of this mode, here we experimentally demonstrate a distinct field-free switching mode in a T-type magnetic system with structure of MgO/CoFeB/Ta/CoFeB/MgO where a perpendicular layer with tilted easy axis was coupled to an in-plane layer with a uniaxial easy axis. Current was applied orthogonal to both easy axes and thus also normal to an in-plane effective field experienced by the perpendicular layer. Dynamic calculation shows perpendicular layer could be switched at the same time as the in-plane layer is switched. These field-free switching modes realized in the same T-type magnetic system might expedite the birth of multi-state spin memories or spin logic devices which could be operated by all electric manners.
A detailed three-dimensional thermal model has been developed to examine the thermal behaviour of a lithium-ion battery. This model precisely considers the layered-structure of the cell stacks, the ...case of a battery pack, and the gap between both elements to achieve a comprehensive analysis. Both location-dependent convection and radiation are adopted at boundaries to reflect different heat dissipation performances on all surfaces. Furthermore, a simplified thermal model is proposed according to the examination of various simplification strategies and validation from the detailed thermal model. Based on the examination, the calculation speed of the simplified model is comparable with that of a one-dimensional model with a maximum error less than 0.54
K. These models successfully describe asymmetric temperature distribution inside a battery, and they predict an anomaly of temperature distribution on the surface if a metal case is used. Based on the simulation results from the detailed thermal model, radiation could contribute 43–63% at most to the overall heat dissipation under natural convection. Forced convection is effective in depressing the maximum temperature, and the temperature uniformity does not necessarily decrease infinitely when the extent of forced convection is enhanced. The metal battery case serves as a heat spreader, and the contact layer provides extra thermal resistance and heat capacity for the system. These factors are important and should be considered seriously in the design of battery systems.
Summary Background Low-dose inhaled corticosteroids (ICS) are highly effective for reducing asthma exacerbations and mortality. Conventionally, ICS treatment is recommended for patients with symptoms ...on more than 2 days per week, but this criterion has scant evidence. We aimed to assess the validity of the previous symptom-based cutoff for starting ICS by establishing whether there was a differential response to budesonide versus placebo for severe asthma exacerbations, lung function, and asthma symptom control across subgroups identified by baseline asthma symptom frequency. Methods We did a post-hoc analysis of the 3 year inhaled Steroid Treatment As Regular Therapy (START) study, done in 32 countries, with clinic visits every 3 months. Patients (aged 4–66 years) with mild asthma diagnosed within the previous 2 years and no previous regular corticosteroids were randomised to receive once daily, inhaled budesonide 400 μg (those aged <11 years 200 μg) or placebo. Coprimary outcomes for this analysis were time to first severe asthma-related event (SARE; hospital admission, emergency treatment, or death) and change from baseline in lung function after bronchodilator. Interaction with baseline symptom frequency was investigated, with patients grouped by more than two symptom days per week and two or fewer symptom days per week (divided into no days to 1 day, and more than 1 day to 2 days). Analysis was done by intention to treat. Findings Of 7138 patients (n=3577 budesonide; n=3561 placebo), baseline symptom frequency was 0–1 days per week for 2184 (31%) participants, more than 1 and less than or equal to 2 symptom days per week for 1914 (27%) participants, and more than 2 symptom days per week for 3040 (43%) participants. For budesonide versus placebo, time to first SARE was longer across symptom frequency subgroups (hazard ratios 0·54 95% CI 0·34–0·86 for 0–1 symptom days per week, 0·60 0·39–0·93 for >1 to ≤2 symptom days per week, 0·57 0·41–0·79 >2 symptom days per week, pinteraction =0·94), and the decline in postbronchodilator lung function was less at 3 years' follow-up (pinteraction =0·32). For budesonide versus placebo, severe exacerbations requiring oral or systemic corticosteroids were reduced (rate ratio 0·48 0·38–0·61 0–1 symptom days per week, 0·56 0·44–0·71 >1 to ≤2 symptom days per week, and 0·66 0·55–0·80 >2 symptom days per week, pinteraction =0·11), prebronchodilator lung function was higher, and symptom-free days were more frequent (p<0·0001 for all three subgroups), with no interaction by symptom frequency (prebronchodilator pinteraction =0·43; symptom-free days pinteraction =0·53). Similar results were noted when participants were classified by any guidelines criterion as so-called persistent versus so-called intermittent asthma. Interpretation In mild recent-onset asthma, once daily, low-dose budesonide decreases SARE risk, reduces lung function decline, and improves symptom control similarly across all symptom subgroups. The results do not support restriction of inhaled corticosteroids to patients with symptoms on more than 2 days per week and suggest that treatment recommendations for mild asthma should consider both risk reduction and symptoms. Funding AstraZeneca.
Energy-transport effects can alter the structure that develops as a supernova evolves into a supernova remnant. The Rayleigh-Taylor instability is thought to produce structure at the interface ...between the stellar ejecta and the circumstellar matter, based on simple models and hydrodynamic simulations. Here we report experimental results from the National Ignition Facility to explore how large energy fluxes, which are present in supernovae, affect this structure. We observed a reduction in Rayleigh-Taylor growth. In analyzing the comparison with supernova SN1993J, a Type II supernova, we found that the energy fluxes produced by heat conduction appear to be larger than the radiative energy fluxes, and large enough to have dramatic consequences. No reported astrophysical simulations have included radiation and heat conduction self-consistently in modeling supernova remnants and these dynamics should be noted in the understanding of young supernova remnants.
Salmonellosis is one of the major food-borne diseases in many countries. This study was carried out to determine the occurrence of Salmonella spp., Salmonella Enteritidis, and Salmonella Typhimurium ...in raw chicken meat from wet markets and hypermarkets in Selangor, as well as to determine the antibiotic susceptibility profile of S. Enteritidis and S. Typhimurium. The most probable number (MPN) in combination with multiplex polymerase chain reaction (mPCR) method was used to quantify the Salmonella spp., S. Enteritidis, and S. Typhimurium in the samples. The occurrence of Salmonella spp., S. Enteritidis, and S. Typhimurium in 120 chicken meat samples were 20.80%, 6.70%, and 2.50%, respectively with estimated quantity varying from <3 to 15 MPN/g. The antibiogram testing revealed differential multi-drug resistance among S. Enteritidis and S. Typhimurium isolates. All the isolates were resistance to erythromycin, penicillin, and vancomycin whereas sensitivity was recorded for Amoxicillin/Clavulanic acid, Gentamicin, Tetracycline, and Trimethoprim. Our findings demonstrated that the retail chicken meat could be a source of multiple antimicrobial-resistance Salmonella and may constitute a public health concern in Malaysia.
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