Effects of a novel refiner Al-3Ti-4.35La combined with Sr on microstructure and mechanical properties of as-cast A356 alloy

It is a practically significant issue to refine and modify industrial Al-Si casting alloy to improve its properties.In the present study,a novel refiner Al-3Ti-4.35La alloy,prepared by a melt-reaction method,was used,combined with Sr to refine the as-cast A356 alloy.Their effects on the as-cast microstructures and mechanical properties of A356 alloy were investigated.The results indicate that the combined addition of Al-3Ti-4.35La intermediate alloy and Sr can improve the microstructure and enhance the mechanical properties of A356 alloy.After adding 0.3wt.%Al-3Ti-4.35La and 0.03wt.%Sr to the as-cast A356 alloy,the average grain size ofα-Al decreases from 693.47μm to 264.13μm(a decrease of 61.91%),the secondary dendrite arm spacing(SDAS)is decreased by 47.8%from 32.09μm to 16.75μm,and the eutectic Si is transformed from an acicular structure to short rods and a granular structure.The ultimate tensile strength(UTS)and elongation(EL)of the as-cast A356 alloy modified by Al-3Ti-4.35La and Sr reach 216.3 MPa and 10.6%,which are enhanced by 29.54%and 134.66%compared with the unmodified alloy,respectively.The fracture mode is transformed from transgranular fracture to intergranular fracture,and the ductile toughness of the alloy is improved.After adding the Al-3Ti-4.35La and Sr,the undercooling for the nucleation ofα-Al and eutectic Si increases,leading to an accelerated nucleation rate and an increased number of nuclei,which shortens the duration of the eutectic reaction and consequently inhibits grain growth.

Therapeutic effects of Clostridium butyricum on experimental colitis induced by oxazolone in rats

AIM： To evaluate the therapeutic effects of a probiotic supplement （Clostridium butyricum, CGMCC0313 ） in a chemically-induced rat model of experimental colitis. METHODS： An experimental ulcerative colitis model was established by rectal injection of oxazolone into the colon of 40 Wistar rats randomly divided into four groups. The positive control group was sacrificed 3 d after colitis onset. The remaining groups were fed daily with either 2 mL of C. butyricum （2.3 × 10^11 CFU/L）, 2 mL of mesalamine （100 g/L）, or 1 mL of sodium butyrate （50 mmol/L） for 21 d. The animals＇ body weight, behavior, and bowel movements were recorded weekly. After sacrifice, visual and microscopic observations of pathological changes of colon tissue were made, body weight and wet colon mass index were measured and recorded, and serum levels of interleukin-23 （IL-23） and TNF-α were measured using ELISA. Expression of calcitonin gene-related peptide in colon tissue was measured by RT-PCR. Finally, changes in rat intestinal microflora status were measured in all groups.lowered the serum levels of both IL-23 and tumor necrosis factor-α （TNF-α） with similar or even better efficiency than that of mesalamine or sodium butyrate. The rat intestinal flora appeared to recover more quickly in the group treated with C. butyricum than in the mesalamine and sodium butyrate groups. Finally, we found that the expression level of calcitonin gene related peptide was elevated in colon tissue in the sodium butyrate treated group but not in the C. butyricum or mesalamine treated groups, indicating a sensitization of colon following sodium butyrate treatment. CONCLUSION： In our experimental colitis model, treatment with C. butyricum CGMCC0313, a probiotic supplement, is at least as efficient as treatment with mesalamine.

Freeze-dried Si-Ni-San powder can ameliorate high fat diet-induced non-alcoholic fatty liver disease

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is a common chronic liver disease worldwide.However,to date,there is no ideal therapy for this disease.AIM To study the effects of Si-Ni-San freeze-dried powder on high fat diet-induced NAFLD in mice.METHODS Twenty-four male C57BL/6 mice were randomized into three groups of eight.The control group(CON)was allowed ad libitum access to a normal chow diet.The high fat diet group(FAT)and Si-Ni-San group(SNS)were allowed ad libitum access to a high fat diet.The SNS group was intragastrically administered Si-Ni-San freeze-dried powder(5.0 g/kg)once daily,and the CON and FAT groups were intragastrically administered distilled water.After 12 wk,body weight,liver index,visceral fat index,serum alanine aminotransferase(ALT),portal lipopoly-saccharide(LPS),liver tumor necrosis factor(TNF)-αand liver triglycerides were measured.Intestinal microbiota were analyzed using a 16S r DNA sequencing technique.RESULTS Compared with the FAT group,the SNS group exhibited decreased body weight,liver index,visceral fat index,serum ALT,portal LPS,liver TNF-αand liver triglycerides(P<0.05).Intestinal microbiota analysis showed that the SNS group had different bacterial composition and function compared with the FAT group.In particular,Oscillospira genus was a bacterial biomarker of SNS group samples.CONCLUSION The beneficial effects of Si-Ni-San freeze-dried powder on high fat diet-induced NAFLD in mice may be associated with its anti-inflammatory and changing intestinal microbiota effects.

不同民族白内障患者眼球生物测量及人工晶状体计算的比较

目的:比较红河哈尼族彝族自治州汉族、哈尼族、彝族眼球生物测量的差异,以及SRK-T,Haigis两种公式在不同眼轴中对人工晶状体(IOL)度数预测的准确性,进一步为少数民族地区广大基层医院及防盲治盲项目提供客观的临床依据。方法:选取就诊于我科的白内障患者186例200眼,按不同民族分为3组,以A超分别联合角膜曲率计及角膜地形图进行眼生物测量(眼轴长度、前房深度、角膜曲率)并比较差异;按不同眼轴分为3组后又随机各分为两组,分别以SRK-T,Haigis进行IOL度数预测,搜集术后验光结果,计算绝对预测误差,并进行统计分析。结果:各民族组间的平均眼轴长度、平均前房深度及平均角膜曲率(分别以角膜地形图及角膜曲率计测量)对比均无差异(P>0.05),两种方法测量的平均角膜曲率比较均无差异(P>0.05);三个眼轴组两种方法测量的平均角膜曲率比较无差异(P>0.05),同一眼轴组内比较均无差异(P>0.05);三个眼轴组两种IOL测量公式计算的绝对误差均无差异(P>0.05);短、中眼轴组SRK-T公式计算绝对误差较小,长眼轴组Haigis公式计算绝对误差较小。结论:我科汉族、哈尼族、彝族白内障患者眼球生物测量无差异,角膜地形图及角膜曲率计测量角膜曲率无差异;SRK-T公式及Haigis公式对IOL度数均具有较高预测性,SRK-T公式对中短眼轴患者预测误差较小,Haigis对长眼轴患者预测性更佳。

Research progress in the treatment of diabetic foot with traditional Chinese medicine

Diabetic foot is one of the chronic complications of diabetes,which is serious and expensive to treat.As an effective method for treating diabetic foot,Chinese medicine plays an important role in improving the clinical symptoms and reducing the suffering of diabetic foot patients.The methods of traditional Chinese medicine to treat diabetic foot include internal treatment method,external treatment method and comprehensive therapy.This article reviews the research results of traditional Chinese medicine treatment of diabetic foot in order to provide reference for the treatment of diabetic foot.

Stabilizing oxygen redox reaction in phase-transition-free P2-type Co/Nifree cathode via Cu doping for sodium-ion batteries

Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale application.This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu doping.Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the cycling.In addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O.Meanwhile,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 C.The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−1.Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.

Recent progress in silk fibroin-based flexible electronics

With the rapid development of the Internet of Things(loT)and the emergence of 5G,traditional silicon-based electronics no Ion ger fully meet market dema nds such as nonplanar application scenarios due to mechanical mismatch.This provides unprecedented opportunities for flexible electronics that bypass the physical rigidity through the introduction of flexible materials.In recent decades,biological materials with outstanding biocompatibility and biodegradability,which are considered some of the most promising candidates for next-generation flexible electronics,have received increasing attention,e.g.,silk fibroin,cellulose,pectin,chitosan,and melanin.Among them,silk fibroin presents greater superiorities in biocompatibility and biodegradability,and moreover,it also possesses a variety of attractive properties,such as adjustable water solubility,remarkable optical transmittance,high mechanical robustness,light weight,and ease of processing,which are partially or even completely lacking in other biological materials.Therefore,silk fibroin has been widely used as fundamental components for the construction of biocompatible flexible electronics,particularly for wearable and implantable devices.Furthermore,in recent years,more attention has been paid to the investigation of the functional characteristics of silk fibroin;such as the dielectric properties,piezoelectric properties,strong ability to lose electrons,and sensitivity to environmental variables.Here,this paper not only reviews the preparation technologies for various forms of silk fibroin and the recent progress in the use of silk fibroin as a fundamental material but also focuses on the recent advaneed works in which silk fibroin serves as functional components.Additi on ally,the challenges and future development of silk fibroin-based flexible electronics are summarized.

Recent advances of ferro-/piezoelectric polarization effect for dendrite-free metal anodes

Metal anodes based on plating/stripping electrochemistry,for instance,common alkaline metal lithium(Li),sodium(Na),potassium(K),polyvalent metal magnesium(Mg),aluminum(Al),calcium(Ca)and zinc(Zn)are imminently evoked and increasingly researched for future generation high-energy-density rechargeable batteries due to their large theoretical capacity,low electrochemical potential,and superior electronic conductivity in recent years.However,the uncontrolled dendrite formation issue induces low Coulombic efficiency,short lifespan,and hazardous security risks,hindering the actual applications of metal batteries.Among various solutions,the utilization of ferro-/piezoelectric materials for metal anodes displays active effects on decreasing local current density,suppressing dendrite growth,and tolerating volume expansion benefits from the unique ferro-/piezoelectric polarization effect.This review presents the research progress of ferro-/piezoelectric polarization effect for regulating the dendritic growth of metal anodes for the first time.First,the current challenges and strategies of metal anodes are proposed.Then,ferro-/piezoelectric materials and their working principle are discussed.Finally,the recent research progress of ferroelectric and piezoelectric materials on dynamic regulation of dendrite growth is summarized,and the future perspectives are prospected.We hope this review could draw more attention in designing metal anodes with self-polarization materials and promoting their practical applications.

Anchoring metal ions in amine-functionalized boron imidazolate framework for photocatalytic reduction of CO_(2)

The photocatalytic reduction of CO_(2)to energy-rich chemicals is highly appealing for alleviation of energy crisis and environment pollution.The introduction of different active sites is a key factor to determine the reaction activity and selectivity.Here,we demonstrate the metal ion-dependent performance for photocatalytic CO_(2)reduction by anchoring transition metal ions(Co^(2+)and Ni^(2+))in an amine-functionalized boron imidazolate framework(BIF-43).As a result,Ni@BIF-43 realized a high selectivity of 90.2%for the CO_(2)-to-CO,while Co@BIF-43 achieved more efficient conversion with a high CO production rate of 2036.0μmol g^(-1)h^(-1).Significantly,precise control of isolated metal site on a well-defined structure through coordination-assisted strategies enables us to better understand the specific effects of different metal-ion species on photoreduction of CO_(2)as well as the catalytic mechanism.

Polymerase chain reaction-based assays facilitate the breeding and study of mouse models of Klinefelter syndrome

Klinefelter syndrome(KS)is one of the most frequent genetic abnormalities and the leading genetic cause of nonobstructive azoospermia.The breeding and study of KS mouse models are essential to advancing our knowledge of the underlying pathological mechanism.Karyotyping and fluorescence in situ hybridization are reliable methods for identifying chromosomal contents.However,technical issues associated with these methods can decrease the efficiency of breeding KS mouse models and limit studies that require rapid identification of target mice.To overcome these limitations,we developed three polymerase chain reaction-based assays to measure specific genetic information,including presence or absence of the sex determining region of chromosome Y(Sry),copy number of amelogenin,X-linked(Amelx),and inactive X specific transcripts(Xist)levels.Through a combined analysis of the assay results,we can infer the karyotype of target mice.We confirmed the utility of our assays with the successful generation of KS mouse models.Our assays are rapid,inexpensive,high capacity,easy to perform,and only require small sample amounts.Therefore,they facilitate the breeding and study of KS mouse models and help advance our knowledge of the pathological mechanism underlying KS.