全物理交联三重互穿网络水凝胶的制备与性能

为提升水凝胶的综合力学力学性能,设计并研究了一种全物理交联三重互穿网络水凝胶。以自由基乳液聚合法,获得疏水缔合交联的聚丙烯酰胺网络,水凝胶一步成型,依次通过冷冻-融化循环、浸没FeCl_(3)溶液分别形成微晶交联的聚乙烯醇网络及离子交联的海藻酸钠网络。获得P(AM-SMA)/PVA/SA三重互穿网络(HMITN)水凝胶。通过傅里叶变换红外对水凝胶结构进行了表征;通过电子万能试验机对水凝胶的力学性能进行了研究。结果表明,HMITN水凝胶具有良好的强度、韧性、抗疲劳及自恢复性能,强度0.45 MPa,断裂能2.48 MJ/m^(3),在200%应变下进行5次循环拉伸后仍然保持20.3%的韧性,室温下自恢复260 min后,韧性可恢复66.7%。

MG7-Ag, hTERT, and TFF2 identified high-risk intestinal metaplasia and constituted a prediction model for gastric cancer

To the Editor:Gastric cancer(GC)ranks third in incidence and mortality both worldwide and in China.[1,2]Intestinal metaplasia(IM)significantly increases risk of GC so that identifying high-risk IM patients who will progress to GC is crucial.Currently,the effect of many risk-stratification methods for gastric precancerous lesions(GPLs)was minimal.Monoclonal gastric cancer 7 antigen(MG7-Ag)combined with cyclooxygenase-2 has been shown earlywarning value for the progression of GPLs.[3]The expression of human telomerase reverse transcriptase(hTERT)was proven to be related to state of cell proliferation in IM tissue.[4]Loss expression of trefoil factor family 2(TFF2)from spasmolytic polypeptideexpressing metaplasia to IM may lead to a hyperproliferation and deleterious mutations.[5]We tried to construct and verify a multimolecular prediction model included MG7-Ag and hTERT and TFF2,which could identify high-risk IM patients and have early-warning value for GC.

In vivo antioxidant activity of rabbiteye blueberry(Vaccinium ashei cv.'Brightwell')anthocyanin extracts

Blueberries are rich in phenolic compounds including anthocyanins which are closely related to biological health functions.The purpose of this study was to investigate the antioxidant activity of blueberry anthocyanins extracted from'Brightwell'rabbiteye blueberries in mice.After one week of adaptation,C57BL/6J healthy male mice were divided into different groups that were administered with 100,400,or 800 mg/kg blueberry anthocyanin extract(BAE),and sacrificed at different time points(0.1,0.5,1,2,4,8,or 12 h).The plasma,eyeball,intestine,liver,and adipose tissues were collected to compare their antioxidant activity,including total antioxidant capacity(T-AOC),superoxide dismutase(SOD)activity and glutathione-peroxidase(GSH-PX/GPX)content,and the oxidative stress marker malondialdehyde(MDA)level.The results showed that blueberry anthocyanins had positive concentration-dependent antioxidant activity in vivo.The greater the concentration of BAE,the higher the T-AOC value,but the lower the MDA level.The enzyme activity of SOD,the content of GSH-PX,and messenger RNA(mRNA)levels of Cu,Zn-SOD,Mn-SOD,and GPX all confirmed that BAE played an antioxidant role after digestion in mice by improving their antioxidant defense.The in vivo antioxidant activity of BAE indicated that blueberry anthocyanins could be developed into functional foods or nutraceuticals with the aim of preventing or treating oxidative stress-related diseases.

Ni_(3)B modified BiVO_(4) photoanodes for enhanced photoelectrochemical water splitting:The key role of Ni_(3)B on reducing the water oxidation barrier

Bismuth vanadate(BiVO_(4),BVO)as a promising photoelectrode has been received great attention for photoelectrochemical(PEC)water splitting.However,the slow oxidation kinetics on the surface of BiVO_(4)limited the PEC water splitting efficiency.Herein,nickel boride(Ni_(3)B,NB)nanoparticles,generally used in electrocatalytic field material,were modified on the surface of BiVO_(4)photoelectrode as an efficient cocatalyst to accelerate the oxygen evolution reaction.The as-prepared BVO-NB-5P photoelectrode exhibits a remarkable photocurrent density of 1.47 mA·cm^(−2)at 1.23 V versus the reversible hydrogen electrode(RHE)under air mass(AM)1.5 G illumination,which is about 2.8 times higher than the bare BiVO_(4)photoelectrode,and its water splitting rate is 11.3 times higher than bare BiVO_(4).The PEC studies reveal that the spin coated Ni_(3)B crystal cocatalyst could effectively reduce the water oxidation barrier,and improve the surface charge injection efficiency to 94%,which could boost the photogenerated holes reaction to enhance the PEC performance of BiVO_(4)photoelectrode.

Analysis of risk factors associated with primary bile reflux:A multicenter cross-sectional study

To the Editor:Bile reflux(BR),also known as duodenogastric reflux,refers to the reflux of duodenal contents such as bile,pancreatic juice,and duodenal juice into the stomach.BR that occurs without gastric surgery is called primary bile reflux(PBR).^([1])A retrospective study showed that the prevalence of PBR in patients with chronic gastritis was as high as 20.5%.^([2])BR can contribute to the development of upper gastrointestinal diseases,^([3–5])but the corresponding risk factors are currently unknown.We aimed to identify the related risk factors for PBR.

Design and analysis of a hypersonic inlet with an integrated bump/forebody

Numerical simulations and experiments showed that bump inlet had a remarkable effect on boundary layer diversion of supersonic flow.However,the design and analysis of bump in hypersonic flow was still few.In this paper,the mechanism of a supersonic bump inlet is introduced to the design of hypersonic forebody.A hypersonic inlet with an integrated bump/forebody is obtained by the Method Of Characteristics(MOC)based on a chin inlet.Numerical simulations show that the modified inlet achieves diversion of low-speed flow.Besides,the integrated bump/-forebody is also beneficial to inlet start.During the starting process,the shape of the separation zone is rebuilt by the modified forebody surface which makes spillage much easier.This new design leads to a reduction of the self-start Mach number by 0.95.

极端湿热环境下隔热的超疏水聚偏氟乙烯/聚酰亚胺纳米纤维复合气凝胶

优异的隔热材料在建筑、航空航天和体育设备等领域有着广泛的应用需求.然而,在实际应用中,隔热材料在不同温度和湿度条件下,其性能往往会恶化.因此,构建在极端湿热环境下仍具有出色的隔热性能的块状材料是非常重要的.在本工作中,我们构思了一种绿色制备策略,即通过静电纺丝和冷冻干燥技术来制备超疏水且可压缩的聚偏氟乙烯/聚酰亚胺(PVDF/PI)纳米纤维复合气凝胶. PVDF纳米纤维和PI纳米纤维分别充当疏水性纤维骨架和机械支撑骨架,形成具有良好机械柔韧性的坚固的三维框架. PVDF/PI气凝胶在室温下具有出色的超疏水特性(水接触角为152°)和低导热性(31.0 m W m^(-1)K^(-1)).同时,在100%湿度(80℃)下, PVDF/PI气凝胶仅显示出48.6 m W m^(-1)K^(-1)的低热导率,其性能优于大多数商业绝热材料.因此,新型的PVDF/PI复合气凝胶有望成为高温和高湿环境中应用的优良隔热材料.

Frictional performance of silicon carbide under different lubrication conditions

The frictional performance of materials used in face seals is critical to the sealing performance.Silicon carbide is commonly used in hard rings because of its abrasion resistance,corrosion resistance,and thermal shock resistance.In this study,the frictional performance of silicon carbide,including graphite-added silicon carbide,under water and lubrication-absent conditions was studied by using a Falex-1506 tribotester and different working parameters.In addition,the morphology of the worn surfaces was observed using scanning electron microscopy and the damage was characterized to understand the tribological behavior of different silicon carbides.The results suggest that the friction coefficients decrease with increasing pressure under water lubrication conditions because of the water within the holes on the surface of the materials.The percentage of water lubrication increases,whereas the percentage of solid friction decreases when the pressure increases.Under dry contact conditions,the friction coefficients change negligibly with increasing pressure and graphite-added silicon carbide shows better frictional performance.

Lysosomal chymotrypsin induces mitochondrial fission in apoptotic cells by proteolytic activation of calcineurin

Dear Editor Apoptosis is a fundamental physiological process in mam- mals in which cells die by activating a suicide mechanism. The mitochondria are one of the major checkpoints in apoptotic regulation because they serve as sensors and amplifiers of cellular damage （Green and Kroemer, 2004）. After mitochondrial outer membrane permeabilization （MOMP）, the mitochondria release a number of factors that are critically involved in cell death signaling （Tait and Green, 2010）. Bcl-2 family members are regarded as the key reg- ulators of mitochondria-dependent apoptosis （Moldoveanu et al., 2014）; however, dynamin-related protein 1 （Drpl）, which orchestrates mitochondrial fission, also participates in apoptotic regulation by stimulating Bax oligomerization and thereby enhances MOMP （Montessuit et al., 2010）; accord- ingly, the inhibition of Drpl blocks mitochondrial fission and inhibits apoptosis （Cassidy-Stone et al., 2008）.