Effects of Aging on Spermatogenesis,Sperm Maturation and Fertility in Mice

Objective To investigate effects of aging on spermatogenesis in testis, sperm maturation in epididymis, and fertility in mice. Methods Testicular specimens, caput epididymal sperm and cauda epididymal sperm were obtained from Kuming mice （18-month aged group, n =15; 6-month young group as control, n=15）. The testicular histological examinations and quantitative evaluations on spermatogenesis were performed. Sperm parameters including sperm density, sperm viability, sperm motility, and normal morphological rate were assessed. The fertilization rate and embryo development were measured by in vitro fertilization and embryo culture. Results The histological changes of testes in aged mice were mainly seminiferous tubule atrophy and hypospermatogenesis. In aged testes, a significant decline was .found in the numbers of round spermatids and elongated spermatids per Sertoli cell （P 〈0.01）. Sperm density, sperm motility and normal morphological rate in caput epididymis and cauda epididymis in aged mice significantly decreased （P〈0.05）. The fertilization rate and embryo development of aged group were lower than those in the control（P〈0. 01）. Conclusions Spermatogenesis and sperm functions could be maintained in the aging male. However, aging affects spermatogenesis and sperm maturation, which leads to lower the quality of sperm, including sperm fertilizing capacity. The development of embryo from aging sperm would have more abnormalities.

Hierarchical monolithic carbon with high transfer performance for hydrogen evolution reaction

Electrocatalysis is an efficient green process for energy conversion.However,for gas-related electrocatalytic reaction,sluggish gas transport has inhibited significantly the promotion of electrocatalytic performances.Herein,hierarchical monolithic material 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) were prepared by3 D printing polyethyleneimine cross-linking oxygenated carbon nanotube and following nickel electrodeposition.3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) have regular pore structure in consistence with3 D printing design and uniform dispersed elements.Amide bonds and carbon defects are presented on the surface of 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) as well as uniformly distributed β-Ni(OH)_(2) on3 DPC-650@Ni/Ni(OH)_(2).3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) present lower overpotentials of 322 and160 mV for hydrogen evolution reaction in 1.0 M KOH at 50 mA cm^(-2),respectively.The ordered channel,high turnover frequency and electrochemically active surface area,hydrophilic and aerophobic properties result in the higher performance of 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) than traditional supports(carbon paper,carbon cloth,and nickel foam) and electrocatalysts.This work provides an efficient pathway for design and preparation of the monolithic electrocatalyst and electrode used for electrochemical reactions where gas is involved.

Screening of transition metal oxides for electrocatalytic nitrate reduction to ammonia at large currents

Electrochemical nitrate reduction reaction(NO_(3)RR)towards ammonia,as an emerging and appealing technology alternative to the energy-intensive Haber-Bosch process and inefficient nitrogen reduction reaction,has recently aroused wide concern and research.However,the current research of the NO_(3)RR towards ammonia lacks the overall performance comparison of various electrocatalysts.Given this,we here make a comparison of 12 common transition metal oxide catalysts for the NO_(3)RR under a high cathodic current density of 0.25 A·cm^(-2),wherein Co_(3)O_(4) catalyst displays the highest ammonia Faradaic efficiency(85.15%)and moderate activity(ca.-0.25 V vs.reversible hydrogen electrode).Other external factors,such as nitrate concentrations in the electrolyte and applied potential ranges,have also been specifically investigated for the NO_(3)RR.

Heterointerface engineering of Ni/Ni_(3)N hierarchical nanoarrays for efficient alkaline hydrogen evolution

Ni-based transition metal nitrides(TMNs)have been regarded as promising substitutes for noble-metal electrocatalysts towards the hydrogen evolution reaction(HER)due to their low cost,excellent chemical stability,high electronic conductivity,and unique electronic structure.However,facile green synthesis and rational microstructure design of Ni-based TMNs electrocatalysts with high HER activity remain challenging.In this work,we report the fabrication of Ni/Ni_(3)N heterostructure nanoarrays on carbon paper via a one-step magnetron sputtering method under low temperature and N2 atmosphere.The Ni/Ni_(3)N hierarchical nanoarrays exhibit an excellent HER catalytic activity with a low overpotential of 37 mV at 10 mA·cm^(−2)and robust long-term durability over 100 h.Furthermore,the Ni/Ni_(3)N||NiFeOH(NiFeOH=NiFe bimetallic hydroxide)electrolyzer requires a small voltage of 1.54 V to obtain 10 mA·cm^(−2)for water electrolysis.Density functional theory(DFT)calculations reveal that the heterointerface between Ni and Ni_(3)N could directly induce electron redistribution to optimize the electronic structure,which accelerates the dissociation of water molecules and the subsequent hydrogen desorption,and thus boosting the HER kinetics.

glmm.hp包对零膨胀广义线性混合模型与多元回归的扩展

glmm.hp是一个专为评估广义线性混合模型(GLMMs)中共线预测变量的相对重要性而开发的R包。自从其于2022年1月发布以来,已迅速在生态学界获得认可和流行。然而,先前的glmm.hp包仅限于处理仅来源于lme4和nlme包的GLMMs。最新的glmm.hp包增加了新功能。首先,它整合了从glmmTMB包获得的结果,使其能够有效地处理零膨胀广义线性混合模型。此外,最新的glmm.hp包添加了基于原始R2和校正R2的普通多元回归的共性分析和层次分割的功能。本文将展示这些新功能,更方便广大的研究人员使用。

R在林业研究中的应用

R是用于数据分析、建模和可视化的强大编程语言之一,广泛运用于各个科学学科,但其林学研究领域受欢迎程度还尚待探索。为了回答这个问题,我们对8种主要林学期刊上2013至2022年间发表的14800多篇研究文章R和R包的使用频率进行了全面分析。分析结果显示,有6700篇文章(占总数的45.7%)明确使用R进行数据分析。R的使用率呈现出持续增长的趋势,从2013年的28.3%上升到2022年的60.9%。使用最多的5个R软件包包括vegan、lme4、nlme、MuMIn和ggplot2。各期刊的关注点有所不同导致R软件包使用频率格局不同。该分析表明,R语言凭借其强大的统计和数据可视化功能,在林学各个领域具有广阔的使用前景。

Pillararenes as Versatile Building Blocks for Fluorescent Materials

Fluorescent materials have received more and more attention in the past few decades because of their great potentials in the fields of luminescent devices,sensing,data storage,bioimaging,and other optical applications.Fluorescent materials comprising organic molecules are of broad interest owing to their highly tunable emission.Initial studies on organic fluorescent materials were mainly focused on the design and covalent modification of fluorophores in order to improve their photophysical properties at the molecular level,whereas in recent decades,many studies have revealed that the intermolecular or intramolecular noncovalent interactions also play a crucial role in luminescence.For example,the modulation of noncovalent interactions in aggregates and selfassemblies was proven to be capable of adjusting aggregation-induced emission(AIE)-active fluorophores by the restriction of intramolecular motions(RIM).In addition,in the crystalline state,intermolecular noncovalent interactions are able to promote phosphorescence by decreasing nonradiative decays.Introducing supramolecular macrocycles into organic fluorescent materials is an intriguing prospect because multiple noncovalent interactions are incorporated.On one hand,the photophysical properties of fluorophores can be changed upon inclusion within the macrocycles,providing unforeseen luminescence.On the other hand,the dynamic and reversible features of host−guest recognition endow the materials with controllability and stimuli-responsiveness,which is beneficial to the fabrication of smart materials.Among numerous supramolecular macrocycles,pillararenes are promising candidates that can be included in fluorescent materials.The advantages of pillararenes are their easy functionalization and planar chirality.After modification with proper substituents,pillararene derivatives possess high solubility and stability in both organic and aqueous media,and reversible guest binding remains.Such features make pillararenes versatile hosts in different environments.Additionally,pillararenes are planar chiral,and the interconversion between enantiomers can be adjusted with different-sized substituents and external stimuli,which are favorable to the construction of chiroptical materials.In this Account,we summarize research progress in the field of pillararene-based luminescent materials,which mainly includes the contributions made by our group.Using pillararenes as building blocks can facilitate the fabrication of high-performance fluorescent materials,in solution or the solid state,with different functions and mechanisms.Therefore,we categorize pillararene-based luminescent materials as those in solution or in the solid state.The applications and the advantages of pillararenes are discussed in detail.For example,in the solid state,pillararene-based host−guest complexation is capable of minimizing the aggregation-caused quenching(ACQ)of fluorophores.This broadens the application of fluorophores in crystalline materials.In solution,the host−guest complexes of pillararenes and fluorophores can self-assemble into well-defined nanostructures,which not only adjust the photophysical properties but also enable functions such as bioimaging.The remaining challenges and future perspectives are outlined at the end.It is expected that this Account will inspire new researchers in different fields and offer new opportunities for the construction of novel luminescent materials with pillararenes and other macrocycles.

蛛网膜囊肿合并脑内血肿一例报道并文献复习

颅内蛛网膜囊肿(intracranial arachnoid cyst,IAC)约占所有颅内占位性病变的1%[1]。IAC合并颅内出血是指IAC患者因某些原因出现与IAC部位相关联的颅内出血,临床上较少见,但因IAC的存在而有其特殊性和复杂性[2-3]。引起此类颅内出血的因素不尽相同,出血部位呈现多样化,其中关于IAC合并脑内血肿的报道少有。而且目前对该类颅内出血的研究报道多以某一部位出血为主,缺乏整体认识[4]。从整体上对IAC合并颅内出血进行分型,有利于深化研究、指导治疗。解放军第九六〇医院神经外科收治了1例外伤致额颞部蛛网膜囊肿合并脑内血肿患者,进一步丰富了IAC合并颅内出血的部位类型,结合该病例并复习国内外相关文献,将IAC合并颅内出血进行总结分型,并对其发病机制及治疗方法进行探讨。