Improvement of high-temperature strength of 6061 Al matrix composite reinforced by dual-phased nano-AlN and submicron-Al_(2)O_(3)particles

Nano-AlN and submicron-Al_(2)O_(3) particles were simultaneously utilized in a 6061 Al matrix composite to improve the high-temperature strength.According to the SEM and TEM characterization,nano-AlN and submicron-Al_(2)O_(3) particles are uniformly distributed in the Al matrix.Brinell hardness results indicate that different from the traditional 6061 Al matrix alloy,the aging kinetics of the composite is obviously accelerated by the reinforcement particles.The T6-treated composite exhibits excellent tensile properties at both room temperature and elevated temperature.Especially at 350℃,the T6-treated composite not only has a high yield strength of 121 MPa and ultimate tensile strength of 128 MPa,but also exhibits a large elongation of 11.6%.Different strengthening mechanisms of nano-AlN and submicron-Al_(2)O_(3) particles were also discussed in detail.

Study on the structure characterization and moisturizing effect of Tremella polysaccharide fermented from GCMCC5.39

The structure and moisture retention of Tremella polysaccharide fermented from GCMCC5.39(FTP)were evaluated.After UV,infrared spectrum analysis,HPAEC-PAD,HPSEC and 1 D NMR analysis,the composition of the purifi ed FTP was determined.Purifi ed components of fermented Tremella polysaccharide(FTPS)was made of galactose,mannose,glucose,galactosmine,glucosamine,and contain a large amount of hydroxyl,carbonyl and amino groups.FTPS wasα-neutral pyranose without uronic acid.FTPS-1 and FTPS-2 were obtained after purifi cation by DEAE-Sepharose Fast Flow Column.The molecular weights of FTPS-1 and FTPS-2 were 25722 and 177263 Da.FTPS-2 had a better ability to prevent moisture loss,and the optimal moisture retention period was 0–4 h.FTPS-2 could signifi cantly increase the moisture content of the skin epidermis and showed a dose-concentration relationship.The effect of FTPS-2 on the expression of different moisturizing genes was evaluated in a human skin keratinocyte model.The results showed that FTPS-2 has no cytotoxicity,and could signifi cantly promote AQP3,TGM1,CASP14,HYAL2,FLG gene expression level in HaCaT cells.It has the most signifi cant infl uence at HYAL2 protein expression on 50μg/mL.

Production, structure, and bioactivity of polysaccharide isolated from Tremella fuciformis

Tremella fuciformis polysaccharide(TFP) is an important bioactive substance in T. fuciformis, which contributes to its application as medicine and food. In the present work, TFP was extracted with enzymatic combined with wet beating and its physicochemical as well as biological activities were investigated in the study. The result showed that the purity of TFP1 reached 92.14%(m/m). The TFP1, purified by DEAE column, had a molecular weight(Mw) of 5.8 × 10^(3) k Da and consisted mainly of mannose, xylose, fucose, glucose and glucuronic acid at a molar ratio of 1.91 : 0.1 : 2.49 : 6.23 : 0.95. The structure of TFP1 was preliminarily investigated by infrared spectroscopy, nuclear magnetic resonance and atomic force microscope(AFM) analysis. Moreover, the antioxidant assays showed that TFP1 could scavenge DPPH, ABTS+ and hydroxyl radicals. The excellent water holding capacity of TFP1 implied its application in the food, pharmaceutical andcosmetic industries.

Effect of Mirena placement on reproductive hormone levels at different time intervals after artificial abortion

BACKGROUND Improper methods of contraception greatly increase the risk of abortion,cervical or endometrial lesions,and the number of recurrent artificial abortions.These complications result in the deterioration of a patient’s outcome.Further,the proportion of artificial abortions is highest among unmarried females.Placement of an intrauterine device,such as the Mirena,after an artificial abortion may decrease the likelihood of an endometrial injury caused by recurrent abortions while significantly improving its contraceptive effects.AIM To discuss the effect of Mirena placement on reproductive hormone levels at different time points after an artificial abortion.METHODS Women(n=119)undergoing an artificial abortion operation were divided into the study(n=56)and control(n=63)groups.In the study group,the Mirena was inserted immediately after the artificial abortion,whereas in the control group,it was inserted 4–7 d after the onset of the first menstrual cycle after abortion.All participants were followed-up for 6 mo to observe the continuation and expulsion rates and adverse reactions and to measure the levels of serum estradiol(E2),follicle stimulating hormone(FSH),and luteinizing hormone(LH).RESULTS The continuation rates were 94.64%and 93.65%in the study group and the control group,respectively.The expulsion rates were 1.79%and 3.17%in the study group and the control group,respectively.There was no statistically significant difference between the two groups(P>0.05).There were also no statistically significant differences in the proportion of patients with bacterial vaginitis,trichomonas vaginitis,or cervicitis between the groups(P>0.05).Six months after Mirena placement,E2 Levels were 45.50±7.13 pg/mL and 42.91±8.10 pg/mL,FSH 13.60±3.24 mIU/mL and 14.54±3.11 mIU/mL,and LH 15.11±2.08 mIU/mL and 14.60±3.55 mIU/mL in the study and control groups,respectively.There were no significant differences in hormone levels between the two groups(P>0.05).There were also no statistically significant differences in the proportions of abnormal menstruation,prolonged menstruation,or pain during intercourse between the study and control groups after Mirena placement(P>0.05).There were no statistically significant differences in uterine volume,sexual desire,sexual activity,or the sexual satisfaction score between the study and control groups before and after Mirena placement(P>0.05).CONCLUSION Placement of a Mirena intrauterine device immediately after an artificial abortion does not increase the risk of adverse reactions and can help prevent endometrial injury caused by recurrent abortions.

A novel heat-resistant Al–Si–Cu–Ni–Mg base material synergistically strengthened by Ni-rich intermetallics and nano-AlN_p microskeletons

In this work, nano-AlN particle(nano-AlN_p) microskeletons were introduced into an Al–Si–Cu–Ni–Mg alloy by Al–8 AlN master alloy in which the nano-AlN_p reinforcements connect with each other to form three-dimensional networks. It is found that these nano-AlN_p microskeletons mainly distribute in the binary Al–Si eutectic zones resulting in flaky eutectic Si phases being modified to particulates. Meanwhile,the microskeletons strengthen the matrix synergistically with semi-continuous Ni-rich intermetallics in three dimensions. The tensile mechanical properties, micro-hardness and thermal expansion properties of the alloy at different temperatures are significantly improved. Especially, the ultimate tensile strength(UTS) at 350℃ increases from 85MPa to 106MPa, rising by 24.7%, which is ascribed to nano-AlN_p microskeletons assisting intermetallics with undertaking mechanical loading, and to the modification of eutectic Si phases to reduce the stress concentration at elevated temperatures.

Co-editing PINK1 and DJ-1 Genes Via Adeno-Associated Virus-Delivered CRISPR/Cas9 System in Adult Monkey Brain Elicits Classical Parkinsonian Phenotype

Whether direct manipulation of Parkinson’s disease(PD)risk genes in the adult monkey brain can elicit a Parkinsonian phenotype remains an unsolved issue.Here,we used an adeno-associated virus serotype 9(AAV9)-delivered CRISPR/Cas9 system to directly co-edit PINK1 and DJ-1 genes in the substantia nigras(SNs)of two monkey groups:an old group and a middle-aged group.After the operation,the old group exhibited all the classic PD symptoms,including bradykinesia,tremor,and postural instability,accompanied by key pathological hallmarks of PD,such as severe nigral dopaminergic neuron loss(>64%)and evidentα-synuclein pathology in the gene-edited SN.In contrast,the phenotype of their middle-aged counterparts,which also showed clear PD symptoms and pathological hallmarks,were less severe.In addition to the higher final total PD scores and more severe pathological changes,the old group were also more susceptible to gene editing by showing a faster process of PD progression.These results suggested that both genetic and aging factors played important roles in the development of PD in the monkeys.Taken together,this system can effectively develop a large number of genetically-edited PD monkeys in a short time(6–10 months),and thus provides a practical transgenic monkey model for future PD studies.

Tuning dual three-dimensional porous copper/graphite composite to achieve diversified utilization of copper current collector for lithium storage

Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite composite with a dual three-dimensional(3 D) continuous porous structure combining used nonsolvent-induced phase separation and heat treatment, in which a large amount of graphite is embedded in the 3 D porous copper/carbon architecture. In the novel structure, not only the electron and Li^(+) transmission performances are improved, but also the space of current collector is fully utilized. Meanwhile,carbonized polyacrylonitrile network stabilizes the interface between graphite and copper matrix. The obtained copper/graphite composite anode has an initial discharge capacity of 524.6 mAh·g^(-1), a holding capacity of350 mAh·g^(-1) and excellent cycle stability(299.3 mAh·g^(-1) after 180 cycles at 0.1 C rate), exhibiting good electrochemical performance. The experimental results show that the mass loading of the copper/graphite composite electrode material is about 4.39 mg·cm^(-2). We also envisage replacing graphite with other high-capacity active materials to fill the current collector, which can provide a reference for the future development of next-generation advanced electrodes.

Separation and quantitative detection of fermentationγ-polyglutamic acid

γ-Polyglutamic acid(γ-PGA)is a kind of polymer material with good biocompatibility and degradability,which is widely used in food,medicine,environmental protection,cosmetics and agriculture.Asγ-PGA is produced by microbial fermentation,its separation,purification and quantitative detection are very important.In this study,the separation methods such as organic solvent precipitation,copper salt precipitation and membrane separation precipitation were mainly discussed,and the quantitative determination methods such as spectrophotometer,enzyme method and viscosity method ofγ-PGA were discussed and compared.Furthermore,Molecular imprinting as a new method for the separation ofγ-PGA has also been analyzed and discussed in order to provide a reference for the separation and purification ofγ-PGA.

Correlation between microbe,physicochemical properties of Jiuqu in different plateau areas and volatile flavor compounds of highland barley alcoholic drink

Highland barley alcoholic drink(HBD),as one of the most typical rice wines in Qinghai-Tibet plateau area,is generally brewed by adding Jiuqu to highland barley.However,the flavor and quality of HBD fermented with Jiuqu in various plateau regions are different.This study elucidated the potential correlation between the microbial community,physicochemical properties of five traditional plateau Jiuqu,namely Hongxin1(HX1),Hongxin2(HX2),Huairang(HR),Hoarfrost gypsophila(HG)and Tibet Qu(TQ),and volatile flavor compounds of HBD.Based on high-throughput sequencing(HTS)technology and LEfSe analysis,it was found that the bacteria and fungi of the five traditional plateau Jiuqu were quite different.Differential microorganisms were Weissella and Pichia in HX1,Lactococcus and Kazachstania in HR,Acetobacter and Rhizopus in TQ.Besides,HX1 and HX2 had higher esterification power,TQ had the highest fermentation power while HR had the lowest enzymatic properties.Finally,RDA and Pearson correlation analysis showed that esterification power and moisture content had positive effects on Lactobacillus,fermentation power and saccharification power were highly positively correlated with Pantoea and Rhizopus,but negatively correlated with Aspergillus.In flavor analysis,Rhizopus,Acetobacter were found positively correlated with alcohols and acids,which contributed to the formation of volatile flavor compounds,Lactobacillus_sanfranciscensis and Lactobacillus_sakei were positively correlated with phenolic compounds.This study showed that the flavor of HBD was seriously affected by the microbiota in Jiuqu,which could help to develop new fortified starter to improve the quality of HBD.