不同密度和剂量猪精的深部输精对母猪繁殖性能的影响

适当降低每次输精时猪精的有效精子数可提高公猪利用效率、减少公猪饲养规模,同时能更充分地利用优秀的公猪。试验以15亿/80 mL规格猪精为对照组,比较12亿/80 mL、12亿/60 mL和10亿/60 mL规格猪精的深部输精对经产母猪繁殖性能的影响。结果显示:受胎率15亿/80 mL>12亿/60 mL>10亿/60 mL>12亿/80 mL,无显著性差异(P>0.05);分娩率15亿/80 mL>12亿/60 mL>12亿/80 mL>10亿/60 mL,无显著性差异(P>0.05);窝均总产仔数、窝均产活仔数、窝均出生重和头均出生重无显著差异(P>0.05)。综合来看,与对照组相比,12亿/60 mL组可以做到不影响繁殖性能,同时使猪精产能提升20%,有推广价值。

DFT Studies on the Antiradical Potential of Phenolic Compounds

Phenolic compounds are a class of hazardous substances for human.To study the antiradical potential of a series of phenolic compounds from the aspect of position and substituent type,phenol,o⁃dihydroxybenzene(ODB),m⁃dihydroxybenzene(MDB),p⁃dihydroxybenzene(PDB),paranitrophenol(PNP),and o⁃chlorophenol(OCP)were selected as typical targets.In addition,to elucidate the degradation discrepancy of phenolic compounds,quantum chemical calculations(QCCs)were obtained using the B3LYP method along with a 6-311G(d,p)basis set.Calculations indicate that phenol,ODB,MDB,and PDB,with electron⁃donating groups,exhibited high antiradical potential,while PNP and OCP,with electron⁃withdrawing groups,exhibited low antiradical potential.The chemical indices calculations show that para⁃compounds and ortho⁃compounds had high antiradical ability.Moreover,phenol,ODB,MDB,and PDB possessed higher bond dissociation enthalpy(BDE)and lower adiabatic ionization potential(AIP)values compared with those of OCP and PNP.Medium effects,even in vacuo,were also taken into account to reveal the antiradical ability of phenolic compounds.

公猪繁殖性能评定

随着规模化养猪业的发展及人工授精技术的普及,公猪繁殖性能已是影响猪场经济效益的重要因素。如何准确评定公猪的繁殖能力,保证人工授精效果,进而保证母猪的繁殖性能的发挥,是养猪人工作中的重要环节。生产实践中最常用的是通过显微镜对猪精细胞水平进行检测。科研人员也在一直研究影响人工授精效果的因素,将精液的检测从细胞水平上升至分子水平,再用分子标记手段将公猪繁殖性能由检测提前至预测,最大限度地保证公猪的繁殖性能,保证优良公猪的性能得到最大程度的发挥。文章从精液品质、人工授精效果、分子水平检测、标记物等几个方面介绍公猪繁殖性能评价时需要衡量的指标,为公猪繁殖性能评定提供参考。

Shape and composition evolution of Pt and Pt_(3)M nanocrystals under HCl chemical etching

Controlling the shape and composition of Pt-based nanocrystals is essential to improve electrocatalytic performance.In this work,we have carefully investigated the evolution process of morphology and composition for Pt and Pt_(3)M(M=Ni,Co)nanocrystals by hydrochloric acid(HCl)etching.As a result,only Pt_(3)Ni nanocrystals successfully formed unsaturated step-like atoms on the surface and then constructed high-index facets(HIFs),while Pt and Pt_(3)Co preserved a good octahedron shape.Density functional theory(DFT)calculation suggests that Cl-ions can be tightly adsorbed on the surface of Pt_(3)Ni rather than other nanocrystals,which hinders the deposition of newly-reduced atoms and thus regulating the surface morphology.Besides,the etching of surface transitional metals further accelerates the formation of HIFs.Boosted by the active sites on the surface,HCl-Pt-Ni exhibited a~10.8 and~11.3 times higher oxygen reduction reaction(ORR)mass and specific activities than commercial Pt/C catalyst,and possessed a good durability after 10,000 cycles test.This work gives a deep insight into the design of high-performance Pt-based ORR catalysts.

电子结肠镜进镜操作难度的相关因素研究

目的通过对肠镜检查的大宗病例进行分析研究,指导临床对拟检患者进镜难度预评估与检查前准备。方法回顾性分析2019年4月至2020年4月吉林大学第一医院胃肠内科·内镜中心所建立的普通肠镜检查数据库共586例病例,根据内镜医生检查过程中对进镜难度的主观评估结果分为E(easy,容易)组与D(difficult,困难)组,对两组间相关临床数据进行对比,并对结肠镜进镜难度相关危险因素包括:主诉是否便秘、口服泻药种类、性别组成、年龄、体质指数(BMI)、既往腹部手术史、进镜时肠道清洁程度进行单因素及多因素分析,进而构建预测结肠镜进镜操作难易程度的列线图模型。结果E组患者与D组患者相比进镜时间更短(10 vs 15 min,P<0.001),需要额外注水来润滑肠道从而降低进镜难度缓解患者疼痛的比例更低(27.7%vs 92.7%,P<0.001),到达回盲部的比例更高(100%vs 96.3%,P<0.001),同时E组患者较D组患者疼痛视觉模糊评分(VAS)更低,痛苦更小(4 vs 5,P<0.001)。单因素分析发现,两组在主诉是否便秘、口服泻药种类、性别组成、年龄、BMI、既往腹部手术史方面存在统计学差异(P均<0.05),而在进镜时肠道准备清洁程度方面无统计学差异(P≥0.05)。进一步行Logistic回归分析结果显示,主诉便秘、BMI低、口服磷酸钠盐口服溶液、腹部手术史是进镜困难的独立危险因素(P均<0.05),综合上述独立危险因素构建了预测结肠镜进镜操作难易程度的列线图模型。结论主诉便秘、BMI低、口服磷酸钠盐口服溶液、腹部手术史是进镜困难的独立危险因素,可利用基于上述独立危险因素构建的列线图模型于检查前预测出受检者肠镜进镜操作的难度,从而指导该结肠镜检查的相关准备。

Solvent-and metal-directed lanthanide-organic frameworks based on pamoic acid:observation of slow magnetization relaxation,magnetocaloric effect and luminescent sensing

Two types of lanthanide coordination polymers, namely, [Ln（PA）（NO3）（DMA）3]n （Ln=Gd （1）, Dy （2）, Eu （3）, Tb （4）） （type I）, and {[Ln2（PA）3（DMF）4]＇2DMF} （Ln=Eu （5）, Tb （6）） （type II） （PA=Pamoic acid, DMA=dimethylacetamide, DMF=N,N-dimethylformamide）, have been synthesized by the reaction of Ln（NO3）a-6H20 with pamoic acid through layer diffusion method. These complexes were characterized by single crystal X-ray diffraction, infrared spectroscopy （IR）, thermogravimetric analysis （TGA）, fluorescence and magnetic measurements. Solvents and lanthanide atoms in the reaction play an important role in controlling different structures. Type I demonstrated 1-D linear chain structure connected by Ln atoms and PA ligands. Type II exhibited non-interpenetrating 3-D 6-connected 43612 nets based on binuclear [Ln2（CO2）6（DMF）4] cores. Magnetic properties of complexes 1-4 were investigated in details. Complex 1 shows significant magnetocaloric effect with -△Sm=20.37 J kg^-1 K^-1 at 3.0 K and 7 T. Complex 2 exhibits slow relaxation of the magnetization. Complexes 3-6 exhibit both ligand- and metal-centered fluorescent properties. Complex 6 demonstrates fluorescent sensing of DMF and Cu^2＋ ion.

Design,synthesis,and biological evaluation of a series of novel cordycepin derivatives

In this study,a novel series of cordycepin derivatives with benzenesulfonamido groups at the 6-position of the purine ring were synthesized and their antitumor activity was evaluated.We revealed the structural moieties of the cordycepin analogs that were required for antitumor activity.Among all the target compounds,those with 4-methyl and 4-nitro substituents on the benzene ring displayed better activity than the lead compound in antiproliferative activity experiments using MDA-MB-231 and A549 cells.However,compounds with 4-methoxybenzene and 2-oxoindoline groups and ethylene spacers displayed more significant activity than the lead compound in antiproliferative activity experiments using He La cells.In particular,a compound with a 4-bromo substituent and an ethylene spacer displayed very high inhibitory activity against the proliferation of MDA-MB-231,A549,and He La cells,suggesting that it had the potential for further development and application.

Prevalence of Salmonella and Antimicrobial Resistance in Isolates from Food Animals—Six PLADs,China,2019

Summary What is already known about this topic?Salmonella causes acute and chronic diseases in food animals,and infected food animals are one of the most important source of human infection.What does this report contribute?The prevalence of Salmonella was 10.5%in chicken samples,24.4%in pig,23.3%in duck,and 29.4%in milk.Salmonella isolates were highly resistant to ampicillin(59.60%).What are the implications for public health practices?Data on Salmonella infections among food animals in China could help identify sources and factors related to the spread of Salmonella in food animals and food production chains.