[Associations between puberty timing and cardiovascular metabolic risk factors among primary and secondary students].

OBJECTIVE: To explore the relationship between puberty timing and cardiovascular metabolic risk factors among primary and secondary students with different genders in Beijing. METHODS: Using the method of stratified cluster sampling by urban and rural areas and school sections, 3 067 students from 16 primary and secondary schools in Fangshan District of Beijing were selected in October 2012, with questionnaire survey, physical examination and serum laboratory testing. In this study, we controlled for confounding factors such as school segments, current residence of the family, birth weight, feeding method, only child, highest educational level of parents, and monthly family income, and then the associations between cardiovascular metabolic risk factors and puberty timing among the primary and secondary students was analyzed by multivariate Logistic analysis. To ensure the reliability of the data, this study adopted strict quality control. RESULTS: A total of 3 067 primary and middle school students aged 7 to 16 years were included in this study, including 1 575 boys and 1 492 girls. The prevalence of premature puberty was 14.73% among the boys and 12.89% among the girls, respectively. The prevalence of delayed puberty was 9.49% among the boys and 10.99% among the girls, respectively. The detection rates of central obesity, hypertension, hyperglycemia, and dyslipidemia among the primary and secondary students were 35.87%, 19.95%, 2.54% and 26.31%, respectively. The detection rates of 1 risk factor clustering, 2 risk factors clustering and more than 3 risk factors clustering were 29.21%, 16.17% and 9.36%, respectively. The difference in the detection rate of cardiovascular and metabolic risk factors in different youth stages was insignificant (P>0.05), the detection rate of risk factor aggregation of 0 was lower than that of the timely group and delayed group, and the detection rate of risk factors aggregation of 2 was higher than that of the timely group (P < 0.05).After adjusting the effects of learning stage, region, birth weight, feeding patterns, one-child, family income and the parents' educational levels, multivariate Logistic regression analysis showed that, compared with the on-time puberty group, the risk of 1 risk factor clustering, 2 risk factors clustering and more than 3 risk factors clustering increased by 1.94 times (95% CI=1.29-2.91), 2.97 times (95% CI=1.89-4.67) and 2.02 times (95% CI= 1.13-3.63) among the girls; It had not been found that the relationship between puberty timing and cardiovascular risk factor clustering among the boys (P>0.05). CONCLUSION: Premature puberty is an independent risk factor for the clustering of cardiometabolic risk factors in girls, and primary prevention strategies should be implemented to reduce the burden of cardiovascular metabolic diseases in the population.

Anchoring Charge Selective Self-Assembled Monolayers for Tin-Lead Perovskite Solar Cells.

Self-assembled monolayers (SAMs) have displayed great potential for improving efficiency and stability in p-i-n perovskite solar cells (PSCs). The anchoring of SAMs at the conductiv metal oxide substrates and their interaction with perovskite materials must be rationally tailored to ensure efficient charge carrier extraction and improved quality of the perovskite films. Herein, SAMs molecules with different anchoring groups and spacers to control the interaction with perovskite in the p-i-n mixed Sn-Pb PSCs are selected. It is found that the monolayer with the carboxylate group exhibits appropriate interaction and has a more favorable orientation and arrangement than that of the phosphate group. This results in reduced nonradiative recombination and enhanced crystallinity. In addition, the short chain length leads to an improved energy level alignment of SAMs with perovskite, improving hole extraction. As a result, the narrow bandgap (≈1.25 eV) Sn-Pb PSCs show efficiencies of up to 23.1% with an open-circuit voltage of up to 0.89 V. Unencapsulated devices retain 93% of their initial efficiency after storage in N2 atmosphere for over 2500 h. Overall, this work highlights the underexplored potential of SAMs for perovskite photovoltaics and provides essential findings on the influence of their structural modification.

Biotoxicity of Halide Perovskites in Mice.

Halide perovskites are crystalline semiconductors with exceptional optoelectronic properties, rapidly developing toward large-scale applications. Lead (II) (Pb2+ ) is the core element used to prepare halide perovskites. Pb2+ can displace key 2+ elements, including calcium, zinc and iron, that regulate vital physiological functions. Sn2+ can replace Pb2+ within the perovskite structure and, if accidentally dispersed in the environment, it readily oxidizes to Sn4+ , which is compatible with physiological functions and thus potentially safe. The 3+ salt bismuth (III) (Bi3+ ) is also potentially safe for the same reason and useful to prepare double perovskites. Here, this work studies the biotoxicity of Pb, Sn, and Bi perovskites in mice for the first time. This work analyses histopathology and growth of mice directly exposed to perovskites and investigate the development of their offspring generation. This study provides the screening of organs and key physiological functions targeted by perovskite exposure to design specific studies in mammalians.

High-Stable Lead-Free Solar Cells Achieved by Surface Reconstruction of Quasi-2D Tin-Based Perovskites.

Tin halide perovskites are an appealing alternative to lead perovskites. However, owing to the lower redox potential of Sn(II)/Sn(IV), particularly under the presence of oxygen and water, the accumulation of Sn(IV) at the surface layer will negatively impact the device's performance and stability. To this end, this work has introduced a novel multifunctional molecule, 1,4-phenyldimethylammonium dibromide diamine (phDMADBr), to form a protective layer on the surface of Sn-based perovskite films. Strong interactions between phDMADBr and the perovskite surface improve electron transfer, passivating uncoordinated Sn(II), and fortify against water and oxygen. In situ grazing incidence wide-angle X-ray scattering (GIWAXS) analysis confirms the enhanced thermal stability of the quasi-2D phase, and hence the overall enhanced stability of the perovskite. Long-term stability in devices is achieved, retaining over 90% of the original efficiency for more than 200 hours in a 10% RH moisture N2 environment. These findings propose a new approach to enhance the operational stability of Sn-based perovskite devices, offering a strategy in advancing lead-free optoelectronic applications.

Managing Excess Lead Iodide with Functionalized Oxo-Graphene Nanosheets for Stable Perovskite Solar Cells.

Stability issues could prevent lead halide perovskite solar cells (PSCs) from commercialization despite it having a comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long-term stability is gaining incremental importance. Excess lead iodide (PbI2 ) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo-graphene nanosheets (Dec-oxoG NSs) to effectively manage the excess PbI2 . Dec-oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec-oxoG NSs leads to a PCE of 23.7 % in inverted (p-i-n) PSCs. The devices retain 93.8 % of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one-sun illumination and exhibit high stability under thermal and ambient conditions.

Highly efficient p-i-n perovskite solar cells that endure temperature variations.

Daily temperature variations induce phase transitions and lattice strains in halide perovskites, challenging their stability in solar cells. We stabilized the perovskite black phase and improved solar cell performance using the ordered dipolar structure of ß-poly(1,1-difluoroethylene) to control perovskite film crystallization and energy alignment. We demonstrated p-i-n perovskite solar cells with a record power conversion efficiency of 24.6% over 18 square millimeters and 23.1% over 1 square centimeter, which retained 96 and 88% of the efficiency after 1000 hours of 1-sun maximum power point tracking at 25° and 75°C, respectively. Devices under rapid thermal cycling between -60° and +80°C showed no sign of fatigue, demonstrating the impact of the ordered dipolar structure on the operational stability of perovskite solar cells.

Associations between different eGFR estimating equations and mortality for CVD patients: A retrospective cohort study based on the NHANES database.

To assess the associations of eGFRCKD-EPI (estimated glomerular filtration rate (eGFR) by chronic kidney disease epidemiology collaboration equation), eGFRMDRD (eGFR by modification of diet in renal disease), and serum creatinine (scr) on the death for American people diagnosed with cardiovascular disease (CVD) respectively, and to compare the predicted performance of eGFRCKD-EPI, eGFRMDRD, and scr. A total of 63,078 participants who derived from the National Health and Nutrition Examination Survey (NHANES) database, were obtained in this retrospective cohort study, and collected the baseline characteristics all participants. The outcomes of our study were defined as death, and eGFR estimating equations was defined as eGFRCKD-EPI, eGFRMDRD, and scr. Univariate and multivariate COX analysis were performed to assess the relationship. A subgroup analysis was conducted based on whether patients had anemia. Simultaneously, we also considered the predictive value of eGFRCKD-EPI, eGFRMDRD, and scr in the risk of death. All patients were followed for at most 5-years. After excluded participants who did not meet the inclusion criteria and had missing information, the present study included 2419 participants ultimately, and were divided into alive group (n = 1800) and dead group (n = 619). The mortality rate for CVD patients in this study was approximately 25.59% at the end of follow-up. After adjustment for covariates, the result showed that participants with eGFRCKD-EPI/eGFRMDRD < 30 mL/min/1.73 m2 or 30 to 45 mL/min/1.73 m2 had a higher risk of mortality. Similarly, participants with scr (Q4 ≥ 1.2) were associated with the increased risk of death. Additionally, eGFRCKD-EPI has a higher predictive value in 1-year, 3-years, and 5-years risk of death among patients with CVD than eGFRMDRD and scr. The lower level of eGFR was associated with higher risk of death among American population diagnosed with CVD, especially for non-anemic patients. Importantly, our study also displayed that CKD-EPI-based calculation equation of eGFR (eGFRCKD-EPI) provided for a better predictive value than eGFRMDRD and scr in the risk of death.

Semi-Planar Non-Fullerene Molecules Enhance the Durability of Flexible Perovskite Solar Cells.

Flexible perovskite solar cells (FPSCs) represent a promising technology in the development of next-generation photovoltaic and optoelectronic devices. SnO2 electron transport layers (ETL) typically undergo significant cracking during the bending process of FPSCs, which can significantly compromise their charge transport properties. Herein, the semi-planar non-fullerene acceptor molecule Y6 (BT-core-based fused-unit dithienothiophen [3,2-b]-pyrrolobenzothiadiazole derivative) is introduced as the buffer layer for SnO2 -based FPSCs. It is found that the Y6 buffer layer can enhance the ability of charge extraction and bending stability for SnO2 ETL. Moreover, the internal stress of perovskite films is also reduced. As a result, SnO2 /Y6-based FPSCs achieved a power conversion efficiency (PCE) of 20.09% and retained over 80% of their initial efficiency after 1000 bending cycles at a curvature radius of 8 mm, while SnO2 -based devices only retain 60% of their initial PCE (18.60%) upon the same bending cycles. In addition, the interfacial charge extraction is also effectively improved in conjunction with reduced defect density upon incorporation of Y6 on the SnO2 ETL, as revealed by femtosecond transient absorption (Fs-TA) measurements.

Antibiotic burden of school children from Tibetan, Hui, and Han groups in the Qinghai-Tibetan Plateau.

BACKGROUND: Given their geographical proximity but differences in cultural and religious dietary customs, we hypothesize that children from the three main ethnic populations (Han, Hui, and Tibetan) residing in the Qinghai-Tibetan Plateau region differs in their non-iatrogenic antibiotic loads. METHODS: To determine the antibiotic burden of the school children unrelated to medical treatment, we quantified the antibiotic residues in morning urine samples from 92 Han, 72 Tibetan, and 85 Muslim Hui primary school children aged 8 to 12 years using high-performance liquid chromatography-tandem mass spectrometry, and performed correlation analysis between these data and concurrent dietary nutrition assessments. RESULTS: Sixteen of the 18 targeted antibiotics (4 macrolides, 3 ß-lactams, 2 tetracyclines, 4 quinolones, 3 sulfonamides, and 2 aminoanols) were identified in the urine samples with an overall detection frequency of 58.63%. The detection frequency of the six antibiotic classes ranged from 1.61% to 32.53% with ofloxacin showing the single highest frequency (18.47%). Paired comparison analysis revealed significant differences in antibiotic distribution frequency among groups, with Tibetans having higher enrofloxacin (P = 0.015) and oxytetracycline (P = 0.021) than Han children. Norfloxacin (a human/veterinary antibiotic) was significantly higher in the Hui children than in the Han children (P = 0.024). Dietary nutrient intake assessments were comparable among participants, showing adequate levels of essential vitamins and minerals across all three ethnic groups. However, significant differences in specific foods were observed among groups, notably in lower fat consumption in the Hui group. CONCLUSIONS: The introduction and accumulation of antibiotic residues in school children through non-iatrogenic routes (food or environmental sources) poses a serious potential health risk and merits closer scrutiny to determine the sources. While the exact sources of misused or overused antibiotics remains unclear, further study can potentially correlate ethnicity-specific dietary practices with the sources of contamination.