Academic Stress, Physical Activity, Sleep, and Mental Health Among Chinese Adolescents

The purpose of this study was to examine the impacts of academic stress on physical activity and sleep, and subsequently their impacts on anxiety and depression. Methods: This cross-sectional study collected data from a convenience sample of 1533 adolescents in an eastern province in China. Surveys were used to collect data on academic stress, anxiety, depression, sleep, physical activity, and demographics. Descriptive statistics, correlation analysis, and path analysis were used to analyze data. Results: The participants reported about 6.77 ± 0.89 h of sleep per day and 1.62 ± 1.79 days of 60 min of physical activity each week. Academic stress was positively correlated with anxiety and depression, which were negatively correlated with physical activity and sleep. The path analysis showed that academic stress directly predicted anxiety (β = 0.54) and depression (β = 0.55), and hours of sleep (β = 0.024) and the number of days of 60 min physical activity (β = 0.014) mediated the relation. Conclusion: The results largely supported our hypotheses and supported the need to lessen academic stress experienced by Chinese adolescents, in effort to enhance mental health indices directly, and by allowing for engagement in health-related behaviors such as physical activity and sleep

Characterization of EndoTT, a novel single-stranded DNA-specific endonuclease from Thermoanaerobacter tengcongensis

EndoTT encoded by tte0829 of Thermoanaerobacter tengcongensis binds and cleaves single-stranded (ss) and damaged double-stranded (ds) DNA in vitro as well as binding dsDNA. In the presence of a low concentration of NaCl, EndoTT cleaved ss regions of damaged dsDNA efficiently but did not cleave DNA that was entirely ss or ds. At high concentrations of NaCl or MgCl2 or ATP, there was also specific cleavage of ssDNA. This suggested a preference for ss/ds junctions to stimulate cleavage of the DNA substrates. EndoTT has six specific sites (a–f) in the oriC region (1–70 nt) of T. tengcongensis. Substitutions of nucleotides around site c prevented cleavage by EndoTT of both sites c and d, implying that the cleavage specificity may depend on both the nucleotide sequence and the secondary structure of the ssDNA. A C-terminal sub-fragment of EndoTT (residues 107–216) had both endonucleolytic and DNA-binding activity, whereas an N-terminal sub-fragment (residues 1–110) displayed only ssDNA-binding activity. Site-directed mutations showed that G170, R172 and G177 are required for the endonuclease activity of EndoTT, but not for DNA-binding, whereas D171, R178 and G189 are partially required for the DNA-binding activity

SabR enhances nikkomycin production via regulating the transcriptional level of sanG, a pathway-specific regulatory gene in Streptomyces ansochromogenes

<p>Abstract</p> <p>Background</p> <p><it>sabR </it>is a pleiotropic regulatory gene which has been shown to positively regulate the nikkomycin biosynthesis and negatively affect the sporulation of <it>Streptomyces ansochromogenes</it>. In this study, we investigate the mechanism of SabR on modulating nikkomycin production in <it>Streptomyces ansochromogenes</it>.</p> <p>Results</p> <p>The transcription start point of <it>sabR </it>was determined by high-resolution S1 nuclease mapping and localized at the nucleotide T at position 37 bp upstream of the potential <it>sabR </it>translation start codon (GTG). Disruption of <it>sabR </it>enhanced its own transcription, but retarded the nikkomycin production. Over-expression of <it>sabR </it>enhanced nikkomycin biosynthesis in <it>Streptomyces ansochromogenes</it>. EMSA analysis showed that SabR bound to the upstream region of <it>sanG</it>, but it did not bind to the upstream region of its encoding gene (<it>sabR</it>), <it>sanF </it>and the intergenic region between <it>sanN </it>and <it>sanO</it>. DNase 1 footprinting assays showed that the SabR-binding site upstream of <it>sanG </it>was 5'-CTTTAAGTCACCTGGCTCATTCGCGTTCGCCCAGCT-3' which was designated as SARE. Deletion of SARE resulted in the delay of nikkomycin production that was similar to that of <it>sabR </it>disruption mutant.</p> <p>Conclusions</p> <p>These results indicated that SabR modulated nikkomycin biosynthesis as an enhancer via interaction with the promoter region of <it>sanG</it>, and expanded our understanding about regulatory cascade in nikkomycin biosynthesis.</p

Macroscopic entanglement between ferrimagnetic magnons and atoms via crossed optical cavity

We consider a two-dimensional opto-magnomechanical (OMM) system including two optical cavity modes, a magnon mode, a phonon mode, and a collection of two-level atoms. In this study, we demonstrate the methodology for generating stationary entanglement between two-level atoms and magnons, which are implemented using two optical cavities inside the setup. Additionally, we investigate the efficiency of transforming entanglement from atom-phonon entanglement to atom-magnon entanglement. The magnons are stimulated by both a bias magnetic field and a microwave magnetic field, and they interact with phonons through the mechanism of magnetostrictive interaction. This interaction generates magnomechanical displacement, which couples to an optical cavity via radiation pressure. We demonstrate that by carefully selecting the frequency detuning of an optical cavity, it is possible to achieve an increase in bipartite entanglements. Furthermore, this improvement is found to be resistant to changes in temperature. The entanglement between atoms and magnons plays a crucial role in the construction of hybrid quantum networks. Our modeling approach exhibits potential applications in the field of magneto-optical trap systems as well.Comment: arXiv admin note: text overlap with arXiv:1903.00221 by other author

Anomalous Photovoltaic Effect in Centrosymmetric Ferroelastic BiVO4

The anomolous photovoltaic (APV) effect is an intriguing phenomenon and rarely observed in bulk materials that structurally have an inversion symmetry. Here, the discovery of such an APV effect in a centrosymmetric vanadate, BiVO4, where noticeable above‐bandgap photovoltage and a steady‐state photocurrent are observed in both ceramics and single crystals even when illuminated under visible light, is reported. Moreover, the photovoltaic voltage can be reversed by the stress modulation, and a sine‐function relationship between the photovoltage and stress directional angle is derived. Microstructure and strain‐field analysis reveal localized asymmetries that are caused by strain fluctuations in bulk centrosymmetric BiVO4. On the basis of the experimental results, a flexoelectric coupling via a strain‐induced local polarization mechanism is suggested to account for the APV effect observed. This work not only allows new applications for BiVO4 in optoelectronic devices but also deepens insights into the mechanisms underlying the APV effect.This work was financially supported by the National Key R&D Program of China (2016YFA0201103), the Natural Science Foundation of China (Grant Nos. 21577143, 51502289, 51872311, and 51502325), the Natural Science Foundation of Fujian Province (Grant Nos. 2017J05031 and 2018I0021), the Frontier Science Key Project of the Chinese Academy of Sciences (QYZDB-SSW-JSC027), and the Instrument Developing Project of Chinese Academy of Sciences (Grant No. ZDKYYQ20180004). Y.L. thanks the Australian Research Council for support in the form of an ARC discovery program grant

HDAC3 maintains oocyte meiosis arrest by repressing amphiregulin expression before the LH surge.

It is known that granulosa cells (GCs) mediate gonadotropin-induced oocyte meiosis resumption by releasing EGF-like factors in mammals, however, the detailed molecular mechanisms remain unclear. Here, we demonstrate that luteinizing hormone (LH) surge-induced histone deacetylase 3 (HDAC3) downregulation in GCs is essential for oocyte maturation. Before the LH surge, HDAC3 is highly expressed in GCs. Transcription factors, such as FOXO1, mediate recruitment of HDAC3 to the amphiregulin (Areg) promoter, which suppresses AREG expression. With the LH surge, decreased HDAC3 in GCs enables histone H3K14 acetylation and binding of the SP1 transcription factor to the Areg promoter to initiate AREG transcription and oocyte maturation. Conditional knockout of Hdac3 in granulosa cells in vivo or inhibition of HDAC3 activity in vitro promotes the maturation of oocytes independent of LH. Taking together, HDAC3 in GCs within ovarian follicles acts as a negative regulator of EGF-like growth factor expression before the LH surge

Comprehensive analysis of the association between inflammation indexes and complications in patients undergoing pancreaticoduodenectomy

BackgroundDuring clinical practice, routine blood tests are commonly performed following pancreaticoduodenectomy (PD). However, the relationship between blood cell counts, inflammation-related indices, and postoperative complications remains unclear.MethodWe conducted a retrospective study, including patients who underwent PD from October 2018 to July 2023 at the First Hospital of Chongqing Medical University, and compared baseline characteristics and clinical outcomes among different groups. Neutrophil count (NC), platelet count (PLT), lymphocyte count (LC), systemic immune-inflammation index (SII), platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and the product of platelet count and neutrophil count (PPN) were derived from postoperative blood test results. We investigated the association between these indicators and outcomes using multivariable logistic regression and restricted cubic spline analysis. The predictive performance of these indicators was assessed by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and decision curve analysis (DCA).ResultA total of 232 patients were included in this study. Multivariate logistic regression and restricted cubic spline analysis showed that all indicators, except for PLT, were associated with clinical postoperative pancreatic fistula (POPF). SII, NLR, and NC were linked to surgical site infection (SSI), while SII, NLR, and PLR were correlated with CD3 complication. PLT levels were related to postoperative hemorrhage. SII (AUC: 0.729), NLR (AUC: 0.713), and NC (AUC: 0.706) effectively predicted clinical POPF.ConclusionIn patients undergoing PD, postoperative inflammation-related indices and blood cell counts are associated with various complications. NLR and PLT can serve as primary indicators post-surgery for monitoring complications

Study on High Intensity Field Emission from Carbon Nanotubes

　　Carbon nanotubes (CNT) were firstly discovered by Iijima in 1991. An ideal nanotube can be considered as a hexagonal network of carbon atoms that has been rolled up to make a seamless hollow cylinder. The CNT length ranges from micrometers to centimeters while the diameter is only several nanometers. There are a variety of applications of CNTs since they have many special properties, such as remarkable electronic transport properties,unusual mechanical properties.　　Among these applications, an important one is to fabricate all kinds of field-emission electron sources. Their huge aspect ratios can dramatically concentrate an applied electric field on their tips; their excellent electric and thermal conductance guarantee good field emission stability; their extremely high melting point makes them possible to work at a critical condition. Therefore, they are considered as promising field emission materials.　　The purpose of this thesis is focused on producing field emitter with large current density, long lifetime, high stability and good repeatability; the following work has been carried out.1.Field-emission theory and properties of carbon nanotubes have been reviewed. The　reason that CNTs are regarded as promising field-emission materials has been　discussed; the main achievements and demerits of current CNT emitters are also　investigated.2.Main equipments related to this research have been introduced, such as experimental　setup for field-emission test, SEM, and magnetron sputtering deposition system.3.The rooting technique has been greatly improved by introducing metal substrates　deposited with thin titanium films. The influence of film thickness on the　field-emission performance has been studied;2μm is decided as appropriate　selection.　More than 15 A/cm2 with a total current of～10mA was reached at～6.0 V/μm. The　lifetime of this kind of emitter was as long as 800 hours at 5.0 A/cm2 with only a　2.50% increase of the applied electric field. By introducing Ti-particles during the　rooting process, the maximum emission current density could reach as high as　338A/cm2, which was the highest value reported so far.4.The influence of nano-sized particles appended to CNTs on field emission has been　investigated; based on the impregnation with RuO2 nano-sized particles and the 　above technique, a low threshold field of ～0.85 V/μm, corresponding to 10 mA/cm2,　has been reached.5.Field-emission arrays (FEA) have been introduced to achieve a high emission current.　The field-emission behavior of a single emitter in a FEA has been studied. A new type　of FEA is put forward to improve the performance of emitters based on this study; the　effect has been experimentally proved. At the same time, the reliance of emission　current density on sample area is also studied.6.The future work has been discussed; new methods have been put forward, which are　very possible to further improve the field emission performance for our field emitters