Learner perceptions of demotivators in the English as a foreign language (EFL) classroom: Conceptual framework, scale development, and tentative underlying cause analysis

Notwithstanding the negative influence of demotivation on student learning outcomes, prior research in EFL demotivation suffers from the lack of generally agreed-upon conceptual understanding, which hampers scale development. The present series of studies sought to explore the ideas of demotivation and describe the development of the Learner Perception of Demotivators Scale (LPDS) both conceptually and psychometrically. In Study 1 (N = 295), an exploratory factor analysis offered preliminary support for a factor structure comprising three dimensions: negative teacher behavior, loss of task value, and low expectancy for success. In Study 2 (N = 320), the proposed factor structure was further corroborated through confirmatory factor analysis, and its validity was documented by means of correlating with academic performance, self-efficacy, and mindset. A second-order factor model was tested to investigate whether a set of demotivating factors load on an overall construct that may be termed “Demotivator”. Whereas the model fit confirmed a wellitting second-order model with post hoc model adjustment, one low first-order loading (negative teacher behavior) does not seem to support “Demotivator” as a higher order construct comprising three subdimensions. Furthermore, the LPDS demonstrated evidence of configural, metric, scalar, and residual invariance across gender, suggesting the same underlying construct is measured across gender groups. Contrary to the findings in motivation research, loss of task value was a stronger predictor of performance than low expectancy for success. Further, in Study 3 (N =320), loss of task value distinguished extremely motivated EFL learners from ordinary ones, offering tentative evidence for the reason behind demotivation in EFL learning. The unique role of task value found in Study 2 and Study 3 gave insights into the hypothetical construct of “demotivation”. It was also examined in the context of East Asian culture. By establishing a nomological network (academic performance, self-efficacy, and mindset), the current study provided a lawful pattern of interrelationships that exists between the hypothetical construct (demotivation) and observable attributes (e.g., academic performance) and that guides researcher for future L2 studies. More implications and limitations for future studies are discussed

Impact of SARS-CoV-2 infection on the association between laboratory tests and severe outcomes among hospitalized children

BACKGROUND: To assist clinicians with identifying children at risk of severe outcomes, we assessed the association between laboratory findings and severe outcomes among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children and determined if SARS-CoV-2 test result status modified the associations. METHODS: We conducted a cross-sectional analysis of participants tested for SARS-CoV-2 infection in 41 pediatric emergency departments in 10 countries. Participants were hospitalized, had laboratory testing performed, and completed 14-day follow-up. The primary objective was to assess the associations between laboratory findings and severe outcomes. The secondary objective was to determine if the SARS-CoV-2 test result modified the associations. RESULTS: We included 1817 participants; 522 (28.7%) SARS-CoV-2 test-positive and 1295 (71.3%) test-negative. Seventy-five (14.4%) test-positive and 174 (13.4%) test-negative children experienced severe outcomes. In regression analysis, we found that among SARS-CoV-2-positive children, procalcitonin ≥0.5 ng/mL (adjusted odds ratio [aOR], 9.14; 95% CI, 2.90-28.80), ferritin \u3e500 ng/mL (aOR, 7.95; 95% CI, 1.89-33.44), D-dimer ≥1500 ng/mL (aOR, 4.57; 95% CI, 1.12-18.68), serum glucose ≥120 mg/dL (aOR, 2.01; 95% CI, 1.06-3.81), lymphocyte count \u3c1.0 × 10 CONCLUSIONS: Specific laboratory parameters are associated with severe outcomes in SARS-CoV-2-infected children, and elevated serum procalcitonin, CRP, and D-dimer and low absolute lymphocyte and platelet counts were more strongly associated with severe outcomes in children testing positive compared with those testing negative

Ablation of elongation factor 2 kinase enhances heat-shock protein 90 chaperone expression and protects cells under proteotoxic stress

Eukaryotic elongation factor 2 kinase (eEF2K) negatively regulates the elongation stage of mRNA translation and is activated under different stress conditions to slow down protein synthesis. One effect of eEF2K is to alter the repertoire of expressed proteins, perhaps to aid survival of stressed cells. Here, we applied pulsed stable isotope labeling with amino acids in cell culture (SILAC) to study changes in the synthesis of specific proteins in human lung adenocarcinoma (A549) cells in which eEF2K had been depleted by an inducible shRNA. We discovered that levels of heat-shock protein 90 (HSP90) are increased in eEF2K-depleted human cells as well as in eEF2K-knockout (eEF2K-/-) mouse embryonic fibroblasts (MEFs). This rise in HSP90 coincided with an increase in the fraction of HSP90 mRNAs associated with translationally active polysomes, irrespective of unchanged total HSP90 levels. These results indicate that blocking eEF2K function can enhance expression of HSP90 chaperones. In eEF2K-/- mouse embryonic fibroblasts (MEFs), inhibition of HSP90 by its specific inhibitor AUY922 promoted the accumulation of ubiquitinated proteins. Notably, HSP90 inhibition promoted apoptosis of eEF2K-/- MEFs under proteostatic stress induced by the proteasome inhibitor MG132. Up-regulation of HSP90 likely protects cells from protein folding stress, arising, for example, from faster rates of polypeptide synthesis due to the lack of eEF2K. Our findings indicate that eEF2K and HSPs closely cooperate to maintain proper proteostasis and suggest that concomitant inhibition of HSP90 and eEF2K could be a strategy to decrease cancer cell survival

Constitutively-active Rheb mutants [T23M] and [E40K] drive increased production and secretion of recombinant protein in Chinese hamster ovary cells

Monoclonal antibodies (mAbs) are high value agents used for disease therapy (‘biologic drugs’) or as diagnostic tools which are widely used in the health care sector. They are generally manufactured in mammalian cells, in particular Chinese hamster ovary (CHO) cells cultured in defined media, and are harvested from the medium. Rheb is a small GTPase which, when bound to GTP, activates mechanistic target of rapamycin complex 1 (mTORC1), a protein kinase that drives anabolic processes including protein synthesis and ribosome biogenesis. Here we show that certain constitutively-active mutants of Rheb drive faster protein synthesis in CHO cells and increase the expression of proteins involved in the processing of secreted proteins in the endoplasmic reticulum, which expands in response to expression of Rheb mutants. Active Rheb mutants, in particular Rheb[T23M], drive increased cell number under serum-free conditions similar to those used in the biotechnology industry. Rheb[T23M] also enhances the expression of the reporter protein luciferase and, especially strongly, the secreted Gaussia luciferase. Moreover, Rheb[T23M] markedly (2-3 fold) enhances the amount of this luciferase and of a model immunoglobulin secreted into the medium. Our data clearly demonstrate that expressing Rheb[T23M] in CHO cells provides a simple approach to promoting their growth in defined medium and the production of secreted proteins of high commercial value

Oral ondansetron administration to nondehydrated children with diarrhea and associated vomiting in emergency departments in Pakistan: A randomized controlled trial

Study objective: We determine whether single-dose oral ondansetron administration to children with vomiting as a result of acute gastroenteritis without dehydration reduces administration of intravenous fluid rehydration.Methods: In this 2-hospital, double-blind, placebo-controlled, emergency department–based, randomized trial conducted in Karachi Pakistan, we recruited children aged 0.5 to 5.0 years, without dehydration, who had diarrhea and greater than or equal to 1 episode of vomiting within 4 hours of arrival. Patients were randomly assigned (1:1), through an Internet-based randomization service using a stratified variable-block randomization scheme, to single-dose oral ondansetron or placebo. The primary endpoint was intravenous rehydration (administration of 20 mL/kg of an isotonic fluid during 4 hours) within 72 hours of randomization.Results: Participant median age was 15 months (interquartile range 10 to 26) and 59.4% (372/626) were male patients. Intravenous rehydration use was 12.1% (38/314) and 11.9% (37/312) in the placebo and ondansetron groups, respectively (odds ratio 0.98; 95% confidence interval [CI] 0.60 to 1.61; difference 0.2%; 95% CI of the difference –4.9% to 5.4%). Bolus fluid administration occurred within 72 hours of randomization in 10.8% (34/314) and 10.3% (27/312) of children administered placebo and ondansetron, respectively (odds ratio 0.95; 95% CI 0.56 to 1.59). A multivariable regression model fitted with treatment group and adjusted for antiemetic administration, antibiotics, zinc prerandomization, and vomiting frequency prerandomization yielded similar results (odds ratio 0.91; 95% CI 0.55 to 1.53). There was no interaction between treatment group and age, greater than or equal to 3 stools in the preceding 24 hours, or greater than or equal to 3 vomiting episodes in the preceding 24 hours.Conclusion: Oral administration of a single dose of ondansetron did not result in a reduction in intravenous rehydration use. In children without dehydration, ondansetron does not improve clinical outcomes

Predicting Adverse Outcomes for Shiga Toxin–Producing Escherichia coli Infections in Emergency Departments

Objective: To assess the performance of a hemolytic uremic syndrome (HUS) severity score among children with Shiga toxin-producing Escherichia coli (STEC) infections and HUS by stratifying them according to their risk of adverse events. The score has not been previously evaluated in a North American acute care setting. Study design: We reviewed medical records of children \u3c18 years old infected with STEC and treated in 1 of 38 participating emergency departments in North America between 2011 and 2015. The HUS severity score (hemoglobin [g/dL] plus 2-times serum creatinine [mg/dL]) was calculated using first available laboratory results. Children with scores \u3e13 were designated as high-risk. We assessed score performance to predict severe adverse events (ie, dialysis, neurologic complication, respiratory failure, and death) using discrimination and net benefit (ie, threshold probability), with subgroup analyses by age and day-of-illness. Results: A total of 167 children had HUS, of whom 92.8% (155/167) had relevant data to calculate the score; 60.6% (94/155) experienced a severe adverse event. Discrimination was acceptable overall (area under the curve 0.71, 95% CI 0.63-0.79) and better among children \u3c5 years old (area under the curve 0.77, 95% CI 0.68-0.87). For children \u3c5 years, greatest net benefit was achieved for a threshold probability \u3e26%. Conclusions: The HUS severity score was able to discriminate between high- and low-risk children \u3c5 years old with STEC-associated HUS at a statistically acceptable level; however, it did not appear to provide clinical benefit at a meaningful risk threshold

Quantitative non-canonical amino acid tagging based proteomics identifies distinct patterns of protein synthesis rapidly induced by hypertrophic agents in cardiomyocytes, revealing new aspects of metabolic remodeling

Cardiomyocytes undergo growth and remodeling in response to specific pathological or physiological conditions. Pathological myocardial growth is a risk factor for cardiac failure to which faster protein synthesis is a major driving element. We aimed to quantify the rapid effects of different pro-hypertrophic stimuli on the synthesis of specific proteins in ARVC and to determine whether such effects are due to alterations on mRNA abundance or the translation of specific mRNAs. Cardiomyocytes have very low rates of protein synthesis, posing a challenging problem in terms of studying changes in the synthesis of specific proteins, which also applies to other non-dividing primary cells. To address this, an optimized QuaNCAT LC/MS method was used to selectively quantify newly synthesized proteins in such cells. The study showed both classical (phenylephrine; PE) and more recent (insulin) pathological cardiac hypertrophic agents increased the synthesis of proteins involved in glycolysis, the Krebs cycle / beta-oxidation, and sarcomeric components. However, insulin increased synthesis of many metabolic enzymes to a greater extent than PE. Using a novel validation method, we confirmed that synthesis of selected candidates is indeed up-regulated by PE and insulin. Synthesis of all proteins studied was upregulated by signaling through mTORC1 without changes in their mRNA levels, showing the key importance of translational control in the rapid effects of hypertrophic stimuli. Expression of PKM2 was upregulated in rat hearts following TAC. This isoform possesses specific regulatory properties that may be involved in metabolic remodeling and as a novel candidate biomarker. Levels of translation factor eEF1 also increased during TAC, likely contributing to faster cell mass accumulation. Interestingly, PKM2 and eEF1 were not up-regulated in pregnancy or exercise induced CH, suggesting them as pathological CH specific markers. The study methods may be of utility to the examination of protein synthesis in primary cells

A randomized trial evaluating virus-specific effects of a combination probiotic in children with acute gastroenteritis

Gastroenteritis accounts for nearly 500,000 deaths in children younger than 5 years annually. Although probiotics have been touted as having the potential to expedite diarrhea resolution, recent clinical trials question their effectiveness. A potential explanation is a shift in pathogens following the introduction of a rotavirus vaccine. Here, we report the results of a multi-center, double-blind trial of 816 children with acute gastroenteritis who completed follow-up and provided multiple stool specimens. Participants were randomized to receive a probiotic containing Lactobacillus rhamnosus and Lactobacillushelveticus or placebo. We report no virus-specific beneficial effects attributable to the probiotic, either in reducing clinical symptoms or viral nucleic acid clearance from stool specimens collected up to 28 days following enrollment. We provide pathophysiological and microbiologic evidence to support the clinical findings and conclude that our data do not support routine probiotic administration to children with acute gastroenteritis, regardless of the infecting virus