39 research outputs found
Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics
The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment. However, the need for high heat transfer rates in thermal harvesting systems is a longstanding obstacle for their practical application. In this work, we construct thermally conductive networks in Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(Zr95Ti5)1−yO3 (lead magnesium niobate–lead antimony–manganese–lead zirconate titanate: PMN–PMS–PZT) ceramics to improve heat transfer and enhance their ferroelectric properties by use of a thermally conductive AlN additive dispersed in the ceramic matrix. The ferroelectric properties, pyroelectric coefficient and thermal conductivity of the PMN–PMS–PZT: AlN composite materials are influenced by the AlN content as a result of the formation of random bridges or thermally conductive networks for phonon transfer in the ceramic matrix, thereby leading to high heat transfer. For a PMN–PMS–PZT composite with a 0.2 wt% AlN content, the ferroelectric properties, pyroelectric coefficient and thermal conductivity are shown to be enhanced owing to the improved crystallinity and density, and the relative permittivity is also reduced, which results in optimized pyroelectric figure of merits. This combination of materials property enhancements is shown to be beneficial for high performance pyroelectric materials in devices for energy harvesting applications
Critical role of ASCT2-mediated amino acid metabolism in promoting leukaemia development and progression
Amino acid (AA) metabolism is involved in diverse cellular functions, including cell survival and growth, however it remains unclear how it regulates normal hematopoiesis versus leukemogenesis. Here, we report that knockout of Slc1a5 (ASCT2), a transporter of neutral AAs, especially glutamine, results in mild to moderate defects in bone marrow and mature blood cell development under steady state conditions. In contrast, constitutive or induced deletion of Slc1a5 decreases leukemia initiation and maintenance driven by the oncogene MLL-AF9 or Pten deficiency. Survival of leukemic mice is prolonged following Slc1a5 deletion, and pharmacological inhibition of ASCT2 also decreases leukemia development and progression in xenograft models of human acute myeloid leukemia. Mechanistically, loss of ASCT2 generates a global effect on cellular metabolism, disrupts leucine influx and mTOR signaling, and induces apoptosis in leukemic cells. Given the substantial difference in reliance on ASCT2-mediated AA metabolism between normal and malignant blood cells, this in vivo study suggests ASCT2 as a promising therapeutic target for the treatment of leukemia
Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics
The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment.</p
Investigating the Relationship between Job Burnout and Job Satisfaction among Chinese Generalist Teachers in Rural Primary Schools: A Serial Mediation Model
Background: Job burnout has become a widespread phenomenon in school settings. However, little is known about the mental health condition of the growing cohort of generalist teachers in rural primary schools. Drawing on the job demands–resource model and social exchange theory, this study examines the correlation between job burnout and job satisfaction through perceived organizational support and work engagement. Methods: We recruited 639 Chinese generalist teachers in rural primary schools as the study subjects and developed a serial mediation model to assess the hypothesized construct. The data acquired online via Wenjuanxing Software were confirmed as valid and analyzed with SPSS and SmartPLS. Results: The participants scored above the median in perceived organizational support, work engagement, and job satisfaction, and had scores close to the median for job burnout. Statistically significant differences among the investigated variables were found in gender, age, experience, and degree. Job burnout was negatively predictive of perceived organizational support, work engagement, and job satisfaction (each p = 0.000). Perceived organizational support mediated the association between job burnout and work engagement (p = 0.000) and the connection between job burnout and job satisfaction (p = 0.000), while work engagement mediated the association between job burnout and job satisfaction (p = 0.000) and the association between perceived organizational support and job satisfaction (p = 0.000). Conclusions: Perceived organizational support and work engagement as two sequential mediators buffered the detrimental impact of job burnout on job satisfaction among Chinese generalist teachers in rural primary schools. Targeted strategies should be implemented to diminish generalist teachers’ feelings of burnout, being unsupported by organizations, disengagement at work, and dissatisfaction with the job
Effects of Cultural Intelligence and Imposter Syndrome on School Belonging through Academic Resilience among University Students with Vocational Backgrounds
Background: University students with vocational qualifications encounter more severe cultural, academic, and self-evaluated challenges in the transitional process than their peers with an academic pathway. This study investigated the predictive effect of cultural intelligence (CI), imposter syndrome (IS), and academic resilience (AR) on school belonging (SB) and their interplay mechanism from a positive and negative perspective. Method: We recruited 326 Chinese university students with a vocational route as the research subjects and designed a parallel mediation model to assess the hypothesized construct. Result: The participants had scores above the median in CI, AR, and SB, but they also obtained scores exceeding the median in moderate IS. CI positively and significantly predicted SB both directly and indirectly through AR, while IS negatively and significantly predicted AR. AR both partly mediated the effect of CI on SB and entirely mediated the impact of IS on SB. Conclusion: CI was the most crucial factor impacting SB, followed by AR and IS among Chinese university students with a vocational education and training (VET) pathway. Strategic interventions should be adopted to enhance their abilities to cope with diverse cultures, promote their resilience in facing academic difficulties, boost their self-achievement, and foster their sense of SB
Integrated geophysical studies on the distribution of Quaternary biogenic gases in the Qaidam Basin, NW China
Quaternary biogenic gas fields in the Sanhu area of the Qaidam Basin are characterized by gentle structures, shallow burial, weak compaction, high porosity and great bulk thickness, which determine their unique geophysical anomalies, such as the locally low gravity, micro-magnetic high frequency anomaly, seismic event push-down and attribute anomaly. An integrated geophysical processing and interpretation scheme is put forward for shallow biogenic gas prediction in this area. Amplitude preservation is performed for 1:100000 gravity data and the processing results are correlated with known gas distributions and aeromagnetic results, remote sensing and seismic hydrocarbon detection. This study shows that the residual gravity low anomaly has a good correlation with the gas field and, as an important feature of the biogenic gas field, the amplitude of residual gravity low anomaly is directly proportional to the measure of gas reservoir. Based on the residual gravity low anomaly and other exploration data, the distribution of gas reservoirs in the Sanhu area is characterized by vertical overlapping, lateral zoning and local enrichment. Residual gravity anomaly, in combination with regional geologic data, reveals three favorable zones, one fairly favorable zone (low gas production zone), five possibly favorable zones and four favorable targets. Key words: Qaidam Basin, Sanhu area, Quaternary, biogenic gas, gravity, magnetic, seismic, geophysical integration, exploration directio
Exploring the Associations between Perceived Organizational Support and Job Burnout among Chinese Academic Journal Editors: A Moderated Mediation Model
Background: Job burnout (JB) has become a prevalent emotional and psychological syndrome across diverse contexts, especially in the face of the COVID-19 pandemic. This study aimed to examine the relationship between perceived organizational support (POS), job satisfaction (JS), self-efficacy (SE), and JB, alongside their mechanism of interplay. Methods: We took 210 Chinese academic journal editors as the research participants and designed a moderated mediation model to examine the posited construct. All the data were gathered online and analyzed with the statistical software SPSS and SmartPLS. Results: The participants comprised 117 women (55.71%) and 93 men (44.29%). There were significant differences among observed variables in age, experience, and title. POS had a significant negative predictive effect on JB (95% CI = −0.43; −0.06). JS mediated the relationship between POS and JB (95% CI = −0.48; −0.11). SE moderated the association between JS and JB (95% CI = 0.04; 0.75) but did not function as a moderator in the relationship between POS and JS (95% CI = −0.01; 0.24). Conclusions: POS, JS, and SE were crucial determinants of JB among Chinese academic journal editors. Targeted interventions should be initiated to diminish editors’ feelings of being unappreciated, inefficient, dissatisfied, and unaccomplished at work