[Long-term trend of the age of spermarche and its association with nutritional status among Chinese Han boys aged 11-18 from 2010 to 2019]

Objective: To analyze the long-term trend of the age of spermarche among Chinese Han boys aged 11 to 18 from 2010 to 2019 and its association with nutritional status. Methods: The data from Chinese National Surveys on Students' Constitution and Health in 2010, 2014 and 2019 were used. The age, residence and spermarche of the participants were collected by questionnaire, and their height and weight were measured. A total of 184 633 Han boys aged 11‒18 years with complete data on spermarche, height, and weight were included in this study. The probability regression method was used to calculate the median age (95%CI) at spermarche in different areas, and the trend of age at spermarche in different groups was compared. The multivariate logistic regression model was used to analyze the association between nutritional status and spermarche of Chinese Han boys aged 11‒18 years. Results: The median age of spermarche (95%CI) was 13.85 (13.45-14.22) years old among Chinese Han boys aged 11‒18 years in 2019, with 0.18 years earlier than that in 2010. The median age at spermarche in urban and rural boys was 13.89 and 13.81 years, respectively. Compared with that in 2010, the age at spermarche in urban and rural boys was 0.08 and 0.27 years earlier, respectively. After adjusting for age, province and urban/rural areas, compared with normal weight, spermarche was negatively associated with wasting and positively associated with overweight and obesity, with OR (95%CI) about 0.73 (0.67-0.80), 1.09 (1.02-1.17) and 1.09 (1.01-1.18), respectively. Conclusion: The age of spermarche generally shows an advanced trend among Chinese Han boys and is associated with nutritional status.

[Prevalence trend of high normal blood pressure and elevated blood pressure in Chinese Han children and adolescents aged 7-17 years from 2010 to 2019]

Objective: To investigate the prevalence trend of high normal blood pressure and elevated blood pressure in children and adolescents aged 7 to 17 years in China from 2010 to 2019. Methods: Students aged 7-17 years were selected from the Chinese National Survey on Students' Constitution and Health from 2010 to 2019. High normal blood pressure and elevated blood pressure were determined according to the "Reference of screening for elevated blood pressure among children and adolescents aged 7-18 years" (WS/T 610-2018). The Chi-square test was performed to determine whether there was a difference in the prevalence of high normal blood pressure and elevated blood pressure by gender, residence and age group. Results: In 2019, the prevalence of high normal blood pressure in children and adolescents aged 7-17 years was 15.3% (29 855/195 625), which was higher in boys (20.2%, 19 779/97 847) and rural areas (15.4%, 15 066/97 567) than that in girls (10.3%, 10 076/97 778) and urban areas (15.1%, 14 789/98 058), respectively (all P<0.05). The prevalence of elevated blood pressure was 13.0% (25 377/195 625), which was higher in girls (13.2%, 12 925/97 778) and rural areas (14.1%, 13 753/97 567) than that in boys (12.7%, 12 452/97 847) and urban areas (11.9%, 11 624/98 058) (all P<0.05). From 2010 to 2019, the prevalence of high normal blood pressure showed an increasing trend, with an annual average growth rate from 1.14% to 3.18%. The overall prevalence of elevated blood pressure also showed an increasing trend from 2010 to 2019 but decreased in 2014. The annual average growth rate of elevated blood pressure was-1.07% from 2010 to 2014 and 9.33% from 2014 to 2019. About 17 provinces had an increasing trend in the prevalence of elevated blood pressure from 2010 to 2014, and 22 provinces with an increasing trend from 2014 to 2019. There were obvious regional differences in the annual average growth rate of the prevalence of high normal blood pressure and elevated blood pressure. The regions with the highest annual average growth rate of the prevalence of high normal blood pressure were the Northeast (5.47%) from 2010 to 2014 and the Western region (5.21%) from 2014 to 2019. For elevated blood pressure, the Northeast had the highest annual average growth rate from 2010 to 2014 (12.35%), while the Central (15.79%) and Western (12.87%) had the highest growth rate from 2014 to 2019. Conclusion: From 2010 to 2019, the prevalence of high normal blood pressure and elevated blood pressure in Chinese Han children and adolescents aged 7 to 17 shows an increasing trend, with regional disparities.

Facial route for high mass loading amorphous NiCo-MOF as high-performance electrode materials toward asymmetric supercapacitor

Herein, amorphous NiCo-MOF with an ultra-high mass loading (10.3 mg cm−2) and an ultra-thick plate structure had been achieved via one-step solvothermal method. Moreover, the corresponding assembled asymmetric supercapacitor depicted...

Sliding induced multiple polarization states in two-dimensional ferroelectrics

When the atomic layers in a non-centrosymmetric van der Waals structure slide against each other, the interfacial charge transfer results in a reversal of the structure's spontaneous polarization. This phenomenon is known as sliding ferroelectricity and it is markedly different from conventional ferroelectric switching mechanisms relying on ion displacement. Here, we present layer dependence as a new dimension to control sliding ferroelectricity. By fabricating 3 R MoS₂ of various thicknesses into dual-gate field-effect transistors, we obtain anomalous intermediate polarization states in multilayer (more than bilayer) 3 R MoS₂. Using results from ab initio density functional theory calculations, we propose a generalized model to describe the ferroelectric switching process in multilayer 3 R MoS₂ and to explain the formation of these intermediate polarization states. This work reveals the critical roles layer number and interlayer dipole coupling play in sliding ferroelectricity and presents a new strategy for the design of novel sliding ferroelectric devices.

Bayesian emulation and history matching of JUNE

We analyze JUNE: a detailed model of COVID-19 transmission with high spatial and demographic resolution, developed as part of the RAMP initiative. JUNE requires substantial computational resources to evaluate, making model calibration and general uncertainty analysis extremely challenging. We describe and employ the uncertainty quantification approaches of Bayes linear emulation and history matching to mimic JUNE and to perform a global parameter search, hence identifying regions of parameter space that produce acceptable matches to observed data, and demonstrating the capability of such methods. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Bayesian emulation and history matching of JUNE

We analyze JUNE: a detailed model of COVID-19 transmission with high spatial and demographic resolution, developed as part of the RAMP initiative. JUNE requires substantial computational resources to evaluate, making model calibration and general uncertainty analysis extremely challenging. We describe and employ the uncertainty quantification approaches of Bayes linear emulation and history matching to mimic JUNE and to perform a global parameter search, hence identifying regions of parameter space that produce acceptable matches to observed data, and demonstrating the capability of such methods. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

β-cryptoxanthin alleviates myocardial ischaemia/reperfusion injury by inhibiting NF-κB-mediated inflammatory signalling in rats

The present study aimed to explore the function and molecular mechanism of β-cryptoxanthin on myocardial ischaemia-reperfusion injury (MIRI). Left anterior descending coronary artery ligation with reperfusion was utilised to establish a MIRI rat model. The results indicated that β-cryptoxanthin decreases infarct size and ameliorates signs of pathological histology in MIRI. TNF-α, IL-1β, and IL-6 levels in the serum were attenuated in response to β-cryptoxanthin treatment, serum LDH and CK-MB activities were also decreased. Immunohistochemical analysis and western blot results suggested that p65 was translocated to the nucleus in the I/R injury rat model. However, in the β-cryptoxanthin administration group, p65 expression and activity in the nucleus were decreased in a dose-dependent manner. Furthermore, p-p38 MAPK levels in response to β-cryptoxanthin were decreased, indicating that MAPK is involved in NF-κB signalling pathway regulation. In conclusion, β-cryptoxanthin alleviates myocardial ischaemia/reperfusion injury by inhibiting NF-κB-mediated inflammatory signalling in rats.

[Effect of outdoor time on the incidence of myopia among primary school students in 9 provinces of China]

Objective: We aimed to assess the effects of outdoor time in preventing incident myopia among primary school students and evaluate its differences among different grades to provide evidence for policy formulation related to myopia prevention. Methods: This study is a cohort study. We investigated 6 046 grade 1 to 5 students in 9 provinces, Jiangsu, Shanghai, Fujian, Shanxi, Henan, Hunan, Gansu, Chongqing, and Guangxi. In 2019, we measured their myopia on site. In 2020, we did a follow-up visit on those students to detect the myopia incidence rate. Information regarding outdoor time and myopia-related behaviors were obtained from a questionnaire within one week of visual acuity measurement in 2020. The chi-square test and Cochran-Armitage trend test compared the differences between groups. The Cox proportional hazards risk model was used to test the relationship between outdoor time and myopia. Results: In 2020, the overall myopia incidence rate of grade 1 to 5 students in the baseline was 27.5%; while 23.0% in grades 1 and 2 students and 31.7% in grades 3 to 5 students, respectively. After controlling for covariates, for students in grade 1 to 2, those with ≥1 hour of outdoor time per day were at 0.76 (95%CI: 0.62-0.93, P=0.008) times risk of being myopia than that of students with <1 hour of outdoor time per day; while for students in grades 3 to 5, an average of ≥3 hours of outdoor time per day was required to have a significant protective effect on myopia. The students with ≥3 hours of outdoor time per day were less likely to be myopia (OR=0.75, 95%CI: 0.61-0.93, P=0.007) than those students with <3 hours of outdoor time per day. Conclusions: For grade 1 and 2 students, 1 hour of outdoor time per day could reduce the incidence of myopia, whereas for grade 3 to 5 students, 3 hours of outdoor time per day could effectively reduce the incidence of myopia. Therefore, the recommendations for outdoor time as myopia prevention should be different for different grades. The higher the grade is, the more outdoor time should be spent to reduce myopia incidence. Moreover, other factors that affect myopia's incidence should be also paid attention to, and a comprehensive approach should be adopted to prevent and control the incidence of myopia.

Assessment of a developed pig cadaver model for teaching crown lengthening surgical procedures

Background

Information regarding using a pig cadaver model for teaching purposes in dentistry is limited, especially for periodontal surgery procedures. The aim of this study was to assess the feasibility and efficacy of teaching crown lengthening surgical procedures using a prepared pig cadaver model.

Methods

Mandibles of slaughtered pigs with subgingival crown fracture defects on two premolars and two molars on each side were prepared as periodontal surgery teaching cases. A resident group (n = 20) and an instructor group (n = 18) participated in assessing the efficacy of the model by completing questionnaires before and after training sessions. Data was either assessed descriptively or analyzed statistically with Wilcoxon signed-rank test with the significance level at α = 0.05.

Results

Results revealed that all the knowledge points showed statistically significant improvements (p < 0.05) except for the procedure to determine the quantity of bone removal during osteotomy procedures. Most residents rated the efficacy of the model obtained with 9.0 out of 10 scale. The data of effectiveness of the pig cadaver model from the instructor group ranged from 7.4 ± 1.4 to 9.0 ± 1.0.

Conclusion

Results of this study support feasibility in using prepared pig cadaver models to teach crown lengthening surgical procedures to postgraduates.

Exchange-Torque-Triggered Fast Switching of Antiferromagnetic Domains

The antiferromagnet is considered to be a promising hosting material for the next generation of magnetic storage due to its high stability and stray-field-free property. Understanding the switching properties of the antiferromagnetic (AFM) domain state is critical for developing AFM spintronics. By utilizing the magneto-optical birefringence effect, we experimentally demonstrate the switching rate of the AFM domain can be enhanced by more than 2 orders of magnitude through applying an alternating square-wave field on a single crystalline Fe/CoO bilayer. The observed extraordinary speed can be much faster than that triggered by a constant field with the same amplitude. The effect can be understood as the efficient suppression of the pinning of AFM domain walls by the strong exchange torque triggered by the reversal of the Fe magnetization, as revealed by spin dynamics simulations. Our finding opens up new opportunities to design the antiferromagnet-based spintronic devices utilizing the ferromagnet-antiferromagnet heterostructure.

Cadmium uptake by a hyperaccumulator and three Pennisetum grasses with associated rhizosphere effects

Pennisetum grasses (P. purpureum Schumach. 'Purple', P. alopecuroides (L.) Spreng. 'Liren' and P. alopecuroides (L.) Spreng. 'Changsui'), and a cadmium (Cd) hyperaccumulator (Thlaspi caerulescens J.Presl & C.Presl), were grown in soil with four Cd addition levels of 0, 2, 20 and 200 mg/kg. Toxicity symptoms were not observed although growth of all plants decreased as Cd addition increased. Shoot bioconcentration factor (BCFS), the translocation factor (TF) and shoot accumulation of Cd for most plants first increased and then declined as Cd concentrations increased. In contrast, the root bioconcentration factor (BCFR) for T. caerulescens declined and root Cd accumulation for T. caerulescens and two P. alopecuroides cultivars increased consistently as Cd levels increased. P. purpureum had the largest biomass with shoot Cd accumulation similar to that of T. caerulescens, despite lower foliar Cd concentration. Although shoot Cd concentrations of two P. alopecuroides cultivars were lower than for P. purpureum, root Cd concentrations were greater. P. purpureum had Cd BCFS and TF (> 1) at 2- and 20-mg/kg Cd addition treatments, similar to T. caerulescens. P. alopecuroides cultivars had Cd BCFR (> 1) and TF (< 1) at all Cd levels. Roots did not affect rhizosphere pH. However, concentrations of acid extractable Cd in rhizosphere soil were lower than those of corresponding non-rhizosphere soil at all Cd levels for T. caerulescens and P. purpureum; T. caerulescens and P. purpureum did not affect less bioavailable Cd fractions. Concentrations of acid extractable Cd in the rhizosphere of the P. alopecuroides cultivars were not reduced at any Cd level. Differences in Cd accumulation among the three Pennisetum grasses were mainly attributable to root biomass and Cd TFs rather than rhizosphere Cd mobility.

In Situ Growing BCN Nanotubes on Carbon Fibers for Novel High-Temperature Supercapacitor with Excellent Cycling Performance

Carbon nanomaterials have elicited much research interest in the energy storage field, but most of them cannot be used at high temperatures. Thus, a supercapacitor with high energy and desired stability at high temperatures is urgently required. Herein, BCN nanotubes (BCNNTs) with excellent performance at high temperatures are generated on carbon fibers by optimizing the ratio of B and N. The nanotubes' morphology can effectively alleviate the structural damage caused by the rapid adsorption/desorption of the electrolyte during long-time charge/discharge cycles at high temperatures, thus improving the high-temperature cycle stability. The symmetric supercapacitors that are assembled with the binder-free BCNNT electrode in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM·BF₄ ) exhibited a high areal capacitance of 177.1 mF cm^-2 at a current density of 5 mA cm^-2 , and capacitance retention is maintained up to 86.1% for 5000 cycles at 100 °C. Moreover, the flexible supercapacitor based on BCNNTs in poly(vinylidenefluoride hexafluoropropylene)/EMIM·BF₄ /succinonitrile gel electrolyte also exhibits good volumetric capacitance (1.98 mWh cm^-3 at a current density of 5 mA cm^-2 ) and cycling stability (92.6% retention after 200 charge/discharge cycles) at a temperature of 100 °C. This work shows that binder-free BCNNTs are promising materials for high-temperature flexible energy storage devices.

Study on Improving the Precise Machinability of Single Crystal SiC by an Ultrasonic-Assisted Hybrid Process

Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing the problems of high cost and unsatisfied performance. To improve the precise machinability of single-crystal SiC wafer, this paper proposed a new hybrid process. Firstly, we developed an ultrasonic vibration-assisted device, by which ultrasonic-assisted lapping and ultrasonic-assisted CMP (chemical mechanical polishing) for SiC wafer were fulfilled. Secondly, a novel three-step ultrasonic-assisted precise machining route was proposed. In the first step, ultrasonic lapping using a cast iron disc was conducted, which quickly removed large surface damages with a high MRR (material removal rate) of 10.93 μm/min. In the second step, ultrasonic lapping using a copper disc was conducted, which reduced the residual surface defects with a high MRR of 6.11 μm/min. In the third step, ultrasonic CMP using a polyurethane pad was conducted, which achieved a smooth and less damaged surface with an MRR of 1.44 μm/h. These results suggest that the ultrasonic-assisted hybrid process can improve the precise machinability of SiC, which will hopefully achieve high-efficiency and ultra-precision machining.

Synthesis and application of low-cost layered double hydroxides intercalated by gluconic acid anion for flame retardancy and tensile strength conservation of high filling epoxy resin

Epoxy resin (EP) is a polymer that is widely used in different aspects of life, but its flammability property limits its fields of applications. Most flame retardants at present cannot be applied practically in scale due to their toxicity, incompatibility in polymers, degraded mechanical property or high cost of raw materials and comprehensive preparation process. Layered double hydroxides intercalated by gluconic acid anion (GLDHs) may serve as a new approach. GLDHs with Mg/Al ratio of 3/1 and 2/1 were first coprecipitated with low-cost green reactants, MgCl₂·6H₂O, AlCl₃·6H₂O, NaOH and sodium gluconate. Their structures were confirmed by X-ray diffractions (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and elemental analysis; their thermal properties were analyzed by thermo gravimetric analysis (TGA). Composites containing 40 wt.% GLDHs were easily manufactured with normal magnetic stirring without any filler precipitation. The combustion properties of the composites filled with 40 wt.% GLDHs2 are as follows: the limit oxygen index (LOI) could rise to 29.8% from 25.2% of pristine EP; UL-94 can reach V-1 level with total burning time of only 12.1 s without dropping; compared to pristine EP, the heat release rate peak (PHRR) could drop to 30% with heavy decrease in the smoke production rate and CO production rate. Dynamic mechanical thermal analysis (DMA) tests showed that the addition of 40 wt.% GLDHs had little impact on the glass transition temperature of the composites and could slightly improve their rigidity and toughness. Tensile strength of the composites filled with 40 wt.% GLDHs2 was almost close to 88% of the tensile strength of pristine EP. Above all, GLDHs with good compatibility in polymers can serve as a promising environmental friendly and low-cost flame retardant for EP and other heterochain polymers.

TDP-43 maintains chondrocyte homeostasis and alleviates cartilage degradation in osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is the most prevalent age-related disorder due to cartilage degradation. Previous studies have identified aberrant chondrocyte homeostasis under extracellular stress as a key pathological mechanism behind cartilage degradation in OA. TDP-43, a DNA/RNA-binding protein has been demonstrated to participate in processing many extracellular stress responses; however, understanding of the role of TDP-43 in OA is limited. This study aims to investigate the role of TDP-43 in chondrocyte homeostasis and cartilage degradation in OA.

METHODS

The role of TDP-43 during degradation of cartilage is examined by experimental posttraumatic OA animal models and human cartilage specimens. Cartilage degradation is assessed by histological analysis, qPCR, and Western blot. The molecular mechanisms are investigated in vitro using human primary chondrocytes.

RESULTS

TDP-43 decreases significantly in degenerated cartilage. TDP-43 concentration is positively correlated with IL-1β concentration in synovial fluid derived from OA patients (Pearson r = 0.95, CI (95%) [0.80, 0.99], P < 0.0001). Intra-articular injection of recombinant TDP-43 significantly alleviates cartilage degradation and subchondral bone remodeling in vivo. In vitro mechanistic analyses show that TDP-43 maintains chondrocyte homeostasis under oxidative stress through regulating stress granule dynamics via G3BP1.

CONCLUSION

The present study indicates that TDP-43 maintains chondrocyte homeostasis under oxidative stress and alleviates cartilage degeneration in osteoarthritis, identifying TDP-43 as a potential target for the diagnosis and treatment of knee OA.