Development of advanced diagnostic techniques for water management in polymer electrolyte fuel cells

Polymer electrolyte fuel cells (PEFCs) are a potential solution to the increasing demand for sustainable energy conversion technologies. One of the long-standing challenges to ensuring efficient and reliable PEFC performance is accomplishing effective internal water management. Here, advanced diagnostic techniques are employed to optimize the water management of PEFCs. Neutron radiography is applied to evaluate the water management of PEFCs under different levels of compression. The PEFC compressed at 1.0 MPa demonstrates ∼3.2 % and ∼7.8 % increase in the maximum power density over 1.8 MPa and 2.3 MPa, respectively. Water droplet number and median droplet surface area rapidly increase with higher compression pressure, showing the ineffective water removal. A systematic comparison is presented of liquid water distribution within the single-, double- and quad-channel serpentine flow-fields. The single-channel serpentine flow-field not only provides the best performance, but also attains the most uniform water profile distribution. The water management of the metal foam and serpentine flow-field based PEFCs have been investigated using neutron radiography. The absence of a land/channel configuration in the metal foam flow-field designs improves the uniformity in reactant distribution across the electrode, contributing to a ~101% increase in maximum power density than the serpentine design. The peak power density of 853 mW cm-2 was recorded for a PEFC with medium compressed metal foam flow-field, followed by maximum (780 mW cm-2) and minimum compression (568 mW cm-2). X-ray computed tomography and simulation results indicate that the compression process significantly decreases the mean pore size and narrows the pore size distribution of metal foams, whereas it leads to larger pressure drop and more effective water removal. A novel transfer function based neutron radiography technique, hydro-electrochemical impedance imaging (HECII) is presented, providing a complementary view to that of conventional neutron imaging in that it highlights the location of nascent water generation

Cómo se relacionan el agotamiento, la resiliencia y el compromiso entre los estudiantes de inglés como lengua extranjera: una investigación de métodos mixtos en el contexto de la escuela secundaria superior china

English-as-a-foreign-language (EFL) learning is essential for Chinese senior high school students, but burnout can impair their engagement and performance. Resilience, however, can enhance their engagement and shield them from burnout. This mixed-methods study aimed to investigate the interplay between burnout, resilience, and engagement among 413 Chinese senior high school EFL learners. Using AMOS 24, quantitative analyses with structural equation modeling (SEM) revealed the reciprocity between these three constructs. Specifically, burnout was negatively associated with both resilience and engagement, explaining 28.6% and 33.3% of their shared variance respectively. Besides, resilience and engagement were positively correlated, sharing 70.6% of their variance. Qualitative semi-structured interviews with 15 students, analyzed by MAXQDA 2022, supported this reciprocity by specifying the role of each component of these constructs. This study also discusses the theoretical and practical implications of findings and suggests directions for future research.El aprendizaje del inglés como lengua extranjera (EFL) es esencial para los estudiantes chinos de secundaria, pero el agotamiento puede afectar su participación y rendimiento. Sin embargo, la resiliencia puede mejorar su participación y protegerlos del agotamiento. Este estudio de métodos mixtos tuvo como objetivo investigar la interacción entre el agotamiento, la resiliencia y la participación entre 414 estudiantes chinos de secundaria que aprenden EFL. Utilizando AMOS 24, los análisis cuantitativos con el modelado de ecuaciones estructurales (SEM) revelaron la reciprocidad entre estas tres construcciones. Específicamente, el agotamiento se asoció negativamente tanto con la resiliencia como con la participación, explicando el 28,6% y el 33,3% de su varianza compartida respectivamente. Además, la resiliencia y la participación se correlacionaron positivamente, compartiendo el 70,6% de su varianza. Las entrevistas cualitativas semiestructuradas con 15 estudiantes, analizadas por MAXQDA 2022, respaldaron esta reciprocidad al especificar el papel de cada componente de estas construcciones. Este estudio también discute las implicaciones teóricas y prácticas de los hallazgos y sugiere direcciones para futuras investigaciones

Cómo se relacionan el agotamiento, la resiliencia y el compromiso entre los estudiantes de inglés como lengua extranjera: una investigación de métodos mixtos en el contexto de la escuela secundaria superior china

English-as-a-foreign-language (EFL) learning is essential for Chinese senior high school students, but burnout can impair their engagement and performance. Resilience, however, can enhance their engagement and shield them from burnout. This mixed-methods study aimed to investigate the interplay between burnout, resilience, and engagement among 413 Chinese senior high school EFL learners. Using AMOS 24, quantitative analyses with structural equation modeling (SEM) revealed the reciprocity between these three constructs. Specifically, burnout was negatively associated with both resilience and engagement, explaining 28.6% and 33.3% of their shared variance respectively. Besides, resilience and engagement were positively correlated, sharing 70.6% of their variance. Qualitative semi-structured interviews with 15 students, analyzed by MAXQDA 2022, supported this reciprocity by specifying the role of each component of these constructs. This study also discusses the theoretical and practical implications of findings and suggests directions for future research.El aprendizaje del inglés como lengua extranjera (EFL) es esencial para los estudiantes chinos de secundaria, pero el agotamiento puede afectar su participación y rendimiento. Sin embargo, la resiliencia puede mejorar su participación y protegerlos del agotamiento. Este estudio de métodos mixtos tuvo como objetivo investigar la interacción entre el agotamiento, la resiliencia y la participación entre 414 estudiantes chinos de secundaria que aprenden EFL. Utilizando AMOS 24, los análisis cuantitativos con el modelado de ecuaciones estructurales (SEM) revelaron la reciprocidad entre estas tres construcciones. Específicamente, el agotamiento se asoció negativamente tanto con la resiliencia como con la participación, explicando el 28,6% y el 33,3% de su varianza compartida respectivamente. Además, la resiliencia y la participación se correlacionaron positivamente, compartiendo el 70,6% de su varianza. Las entrevistas cualitativas semiestructuradas con 15 estudiantes, analizadas por MAXQDA 2022, respaldaron esta reciprocidad al especificar el papel de cada componente de estas construcciones. Este estudio también discute las implicaciones teóricas y prácticas de los hallazgos y sugiere direcciones para futuras investigaciones. &nbsp

Social prediction: a new research paradigm based on machine learning

Sociology is a science concerned with both the interpretive understanding of social action and the corresponding causal explanation, process, and result. A causal explanation should be the foundation of prediction. For many years, due to data and computing power constraints, quantitative research in social science has primarily focused on statistical tests to analyze correlations and causality, leaving predictions largely ignored. By sorting out the historical context of "social prediction," this article redefines this concept by introducing why and how machine learning can help prediction in a scientific way. Furthermore, this article summarizes the academic value and governance value of social prediction and suggests that it is a potential breakthrough in the contemporary social research paradigm. We believe that through machine learning, we can witness the advent of an era of a paradigm shift from correlation and causality to social prediction. This shift will provide a rare opportunity for sociology in China to become the international frontier of computational social sciences and accelerate the construction of philosophy and social science with Chinese characteristics

Coexistence of Histologically Confirmed Hashimoto's Thyroiditis with Different Stages of Papillary Thyroid Carcinoma in a Consecutive Chinese Cohort

Purpose. To determine the relationship between Hashimoto's thyroiditis (HT) and all stages of papillary thyroid carcinoma (PTC) with or without local lymph node metastasis (LNM). Methods:. We conducted a retrospective study of thyroidectomies from 2008–2013 in First Affiliated Hospital of Nanjing Medical University. We categorized patients according to the presence of histopathologically proven HT. The prevalence of mPTC (maximum diameter ≤ 10 mm) and crPTC (clinical relevant PTC) and local LNM rates were compared. Results:. We evaluated 6,432 consecutive thyroidectomies. In total, 1,328 specimens were confirmed as HT. The prevalence of PTC in this HT cohort was 43.8%, significantly higher than non-HT group. After adjustment of gender and age, the prevalence of PTC was still higher in HT group. HT was a risk factor for PTC in multivariate analysis with odds ratio 2.725 (95% CI, 2.390–3.109) (P < 0.001). However, no correlation was found between HT and LNM of PTC. Conclusion:. HT was associated with an increased prevalence of all stages of PTC, independent of tumor size, gender, and age. In contrast, locally advanced disease defined by LNM was unrelated to HT. These data suggest an association of HT with low risk PTC and a potential protective immunologic effect from further disease progression

Efficacy and safety of tigecycline monotherapy vs. imipenem/cilastatin in Chinese patients with complicated intra-abdominal infections: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Tigecycline, a first-in-class broad-spectrum glycylcycline antibiotic, has broad-spectrum in vitro activity against bacteria commonly encountered in complicated intra-abdominal infections (cIAIs), including aerobic and facultative Gram-positive and Gram-negative bacteria and anaerobic bacteria. In the current trial, tigecycline was evaluated for safety and efficacy vs. imipenem/cilastatin in hospitalized Chinese patients with cIAIs.</p> <p>Methods</p> <p>In this phase 3, multicenter, open-label study, patients were randomly assigned to receive IV tigecycline or imipenem/cilastatin for ≤2 weeks. The primary efficacy endpoints were clinical response at the test-of-cure visit (12-37 days after therapy) for the microbiologic modified intent-to-treat and microbiologically evaluable populations. Because the study was not powered to demonstrate non-inferiority between tigecycline and imipenem/cilastatin, no formal statistical analysis was performed. Two-sided 95% confidence intervals (CIs) were calculated for the response rates in each treatment group and for differences between treatment groups for descriptive purposes.</p> <p>Results</p> <p>One hundred ninety-nine patients received ≥1 dose of study drug and comprised the modified intent-to-treat population. In the microbiologically evaluable population, 86.5% (45 of 52) of tigecycline- and 97.9% (47 of 48) of imipenem/cilastatin-treated patients were cured at the test-of-cure assessment (12-37 days after therapy); in the microbiologic modified intent-to-treat population, cure rates were 81.7% (49 of 60) and 90.9% (50 of 55), respectively. The overall incidence of treatment-emergent adverse events was 80.4% for tigecycline vs. 53.9% after imipenem/cilastatin therapy (<it>P </it>< 0.001), primarily due to gastrointestinal-related events, especially nausea (21.6% vs. 3.9%; <it>P </it>< 0.001) and vomiting (12.4% vs. 2.0%; <it>P </it>= 0.005).</p> <p>Conclusions</p> <p>Clinical cure rates for tigecycline were consistent with those found in global cIAI studies. The overall safety profile was also consistent with that observed in global studies of tigecycline for treatment of cIAI, as well as that observed in analyses of Chinese patients in those studies; no novel trends were observed.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00136201</p

Pharmacokinetics/pharmacodynamics of polymyxin B in patients with bloodstream infection caused by carbapenem-resistant Klebsiella pneumoniae

Introduction: Polymyxin B is a last-line therapy for carbapenem-resistant microorganisms. However, a lack of clinical pharmacokinetic/pharmacodynamic (PK/PD) data has substantially hindered dose optimization and breakpoint setting.Methods: A prospective, multi-center clinical trial was undertaken with polymyxin B [2.5 mg/kg loading dose (3-h infusion), 1.25 mg/kg/12 h maintenance dose (2-h infusion)] for treatment of carbapenem-resistant K. pneumoniae (CRKP) bloodstream infections (BSI). Safety, clinical and microbiological efficacy were evaluated. A validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was applied to determine the concentrations of polymyxin B in blood samples. Population pharmacokinetic (PK) modeling and Monte Carlo simulations were conducted to examine the susceptibility breakpoint for polymyxin B against BSI caused by CRKP.Results: Nine patients were enrolled and evaluated for safety. Neurotoxicity (5/9), nephrotoxicity (5/9), and hyperpigmentation (1/9) were recorded. Blood cultures were negative within 3 days of commencing therapy in all 8 patients evaluated for microbiological efficacy, and clinical cure or improvement occurred in 6 of 8 patients. Cmax and Cmin following the loading dose were 5.53 ± 1.80 and 1.62 ± 0.41 mg/L, respectively. With maintenance dosing, AUCss,24 h was 79.6 ± 25.0 mg h/L and Css,avg 3.35 ± 1.06 mg/L. Monte Carlo simulations indicated that a 1 mg/kg/12-hourly maintenance dose could achieve &gt;90% probability of target attainment (PTA) for isolates with minimum inhibitory concentration (MIC) ≤1 mg/L. PTA dropped substantially for MICs ≥2 mg/L, even with a maximally recommended daily dose of 1.5 mg/kg/12-hourly.Conclusion: This is the first clinical PK/PD study evaluating polymyxin B for BSI. These results will assist to optimize polymyxin B therapy and establish its breakpoints for CRKP BSI