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Abnormal mechanochemical effect in ultraprecision machining of an additively manufactured precipitation-strengthened high-entropy alloy

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Journal of Materials Science & Technology 2024年第3期170卷 221-237页

作者： long Xu Yuchao Bai Yunfa Guo chang Ren Xiaohua Tan yandong Jia Gang Wang Hao Wang Institute of Materials Shanghai UniversityShanghai 200444China Zhejiang Institute of Advanced Materials Shanghai UniversityJiashan 314100China Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore

Recently,researchers have explored the use of precipitation strengthening and finer microstructures with high-density dislocations in additive manufacturing to produce high-entropy alloys(HEAs)with adjustable ***,the inherent surface roughness and lack of machinability research in AMed HEAs limit their engineering *** this study,we systematically investigated the microstructural characteristics,mechanical properties,and machinability of Fe_(29.3)Co_(28.7)Ni_(28.6)Al_(6.8)Ti_(6.6)(at.%)HEAs with three different structures:single FCC phase cellular(SPC),dual precipitation-strengthened(DPS),and single precipitation-strengthened(SPS).These structures were fabricated by selective laser melting and isothermally annealing at 780 and 940℃.Compared to SPC HEA,DPS HEA exhibits a significant increase in yield strength and ultimate tensile strength but with a dramatic sacrifice in *** HEA exhibits similar mechanical properties to SPC HEA due to the pronounced coarsening of L21 *** ultraprecision machining micro-cutting test showed that SPC HEA had a significant mechanochem-ical effect,as evidenced by a sharp drop in cutting force for inked workpieces,but not DPS *** abnormal finding was that the negligible reflection of cutting force for SPS HEAs suggested a negative mechanochemical effect,even though SPS HEA had equally excellent plasticity like SPC *** was found that nanocrystallization-induced strength enhancement and ductility reduction of SPS HEA lead to chips’deformation dominated by shear avalanche rather than chip folding of SPC HEA,which involves the reduction of surface energy and friction of chips’***,these results and our research findings may guide the machining of AMed precipitation-strengthened HEAs and accelerate their engineering ap-plication.

关键词： High-entropy alloy Selective laser melting Precipitation strengthening Machinability Mechanochemical effect

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Sequence structure controllable polymerization-induced self-assembly

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Science China Chemistry 2024年第1期67卷 390-397页

作者： Zi-Xuan chang Ren-Man Zhu Chun-yan Hong Wen-Jian Zhang Department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Key Laboratory of Environment-Friendly Polymeric Materials of Anhui Province Anhui UniversityHefei 230601China

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating ***,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific ***,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a *** the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat ***-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of ***,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in *** versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

关键词： polymerization-induced self-assembly sequence-controlled polymers PET-RAFT polymerization

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A buffer overflow detection and defense method based on RiSC-V instruction set extension

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Cybersecurity 2024年第2期7卷 28-43页

作者： chang Liu yan-Jun Wu Jing-Zheng Wu Chen Zhao Intelligent Software Research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop

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Artemsieverolactones A—H,Eight Guaiane-Type Sesquiterpenoid Trimers from Artemisia sieversiana

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Chinese Journal of Chemistry 2024年第10期42卷 1084-1092页

作者： Wei Dong Xiao-yan Huang Tian-Ze Li yan-Mei Weng chang-An Geng Ji-Jun Chen State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China University of Chinese Academyof Sciences Beijing 100049China

Eight new guaiane-type sesquiterpenoid trimers,artemsieverolactones A—H,possessing unprecedented scaffolds via biocatalyzed[4+2]Diels−Alder cycloaddition reactions were identified from Artemisia *** structures were determined by comprehensive spectroscopic data,single-crystal X-ray diffraction analyses,and ECD *** terms of structure,artemsieverolactones A—H are first examples of sesquiterpenoid trimers from guaiane-type sesquiterpenoid through four different[4+2]Diels−Alder cycloaddition *** fibrosis assay suggested that five compounds exhibited activity against HSC-LX2 with IC_(50)values ranging from 37.8 to 117.1μmol/*** most active artemsieverolactone B(2)displayed significant inhibitory activity against HSC-LX2 with IC_(50)value of 37.8μmol/L,which was 3 times more active than the positive drug silybin(IC_(50),139.7μmol/L).Preliminary mechanism study revealed that artemsieverolactone B could inhibit the deposition of human collagen typeⅠ(ColⅠ),human hyaluronic acid(HA),and human laminin(HL)with IC_(50)values of 40.4μmol/L(Col I),55.1μmol/L(HL),47.3μmol/L(HA),which was 2 to 3-fold more potent than silybin.

关键词： Artemisia sieversiana Artemsieverolactones A-H Guaiane-type sesquiterpenoid trimers Antihepatic fibrosis Extracellular matrix Cancer NMR spectroscopy X-ray diffraction

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Effect of cerium alloying on microstructure,texture and mechanical properties of magnesium during cold-rolling process

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Journal of Rare Earths 2024年第5期42卷 1001-1008,I0007页

作者： Zhen Zhang Huanhuan Chen Shiju Cao Jinhua Peng Peng Guo chang long Shan Wang chang Chen Yong Wu Ji'an Huang Xiaodong Du Haigen Wei School of Materials Science and Engineering Hefei University of TechnologyHefei230009China NationalLocal Joint Research Center of Non-ferrous Metal Materials and Processing Technology Hefei230009China Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province Hefei230009China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China Institute of Industry and Equipment Technology Hefei University of TechnologyHefei230009China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou341000China

Hot-extrusion and cold-rolling were conducted on Mg-Ce binary alloys to explore the effect of cerium(Ce)on microstructure,texture and mechanical properties of Mg *** addition of Ce results in significant grain refinement both in as-cast and hot-extruded *** basal texture is also weakened after extrusion and an inclined basal texture is formed with Ce *** strength and elongation of the Mg-Ce alloys are improved simultaneously due to such grain refinement and texture weakening *** cold-rolling,plenty of twins are found in the pure Mg and AZ31 plates while grains in the Mg-0.3Ce plate deform more uniformly without lamellar twin ***,Mg-0.3Ce alloys own strong and continuous strain hardening because Ce atoms and Mg-Ce precipitated phases serve as obstacles for dislocation slip.

关键词： Mg-Ce alloys Hot extrusion Cold-rolling Rare earths

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Clinical application of eight-zone laparoscopic dissection strategy for rectal cancer:Experience and discussion

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World Journal of Gastroenterology 2024年第30期30卷 3574-3583页

作者： chang Chen Xiang Zhang Xin Li yan-Lei Wang Department of General Surgery Rongchang People's HospitalChongqing 250012China Department of Colorectal Surgery Qilu HospitalShandong UniversityJinan 250012Shandong ProvinceChina Department of General Surgery Huantai Branch of Qilu Hospital of Shandong UniversityZibo 255000Shandong ProvinceChina

BACKGROUND The incidence of rectal cancer is increasing worldwide,and surgery remains the primary treatment *** the advent of total mesorectal excision(TME)technique,the probability of tumor recurrence post-surgery has significantly ***'focus has gradually shifted towards minimizing the impact of surgery on urinary and sexual *** these concerns,the optimal dissection of the rectal lateral ligaments and preservation of the pelvic floor neuro-vascular bundle have become *** explore the optimal surgical technique for TME and establish a standardized surgical protocol to minimize the impact on urinary and sexual functions,we propose the eight-zone dissection strategy for pelvic floor *** To compare the differences in surgical specimen integrity and postoperative quality of life satisfaction between the traditional pelvic floor dissection strategy and the innovative eight-zone dissection *** We analyzed the perioperative data of patients who underwent laparoscopic radical resection of rectal cancer at Qilu Hospital of Shandong University between January 1,2021 and December 1,*** study included a total of 218 patients undergoing laparoscopic radical surgery for rectal cancer,among whom 109 patients underwent traditional pelvic floor dissection strategy,and 109 patients received the eight-zone dissection *** There were no significant differences in general characteristics between the two *** in the eight-zone dissection group had higher postoperative specimen integrity(88.1%vs 78.0%,P=0.047).At the 3-month followup,patients in the eight-zone surgery group had better scores in urinary issues(6.8±3.3 vs 5.3±2.5,P=0.045)and male sexual desire(2.2±0.6 vs 2.5±0.5,P=0.047)compared to the traditional surgery strategy *** This study demonstrates that the eight-zone dissection strategy for laparoscopic lateral ligament dissection of rectal cancer is safe and ***

关键词： Eight-zone dissection strategy Rectal cancer Lateral ligament dissection Nerve injury Total mesorectal excision surgery

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Luteolin promotes neuronogenesis in hippocampus of chronic unpredictable mild stress rats and primary hippocampus of fetal rats

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Journal of Traditional Chinese Medicine 2024年第4期44卷 670-679页

作者： LIU Tongtong ZHANG Xi yanG Hui LIN Xiaoyuan LIU Jian ZHANG Xiuli GUO Dongwei ZHAO Hongqing ZOU Manshu LEI chang long Hongping LUO yan XIANG Yun GE Jinwen WANG Yuhong MENG Pan Institute of Innovation and Applied Research in Chinese Medicine Hunan University of Chinese MedicineChangsha 410208China the Second People's Hospital of Hunan Province Changsha 410007China The First Affiliated Hospital Hunan University of Chinese MedicineChangsha 410007China Hunan Academy of Chinese Medicine Changsha 410013China

OBJECTIVE:To investigate the effects of luteolin on chronic unpredictable mild stress(CUMS)-induced depressive rats and corticosterone(CORT)-induced depressive primary hippocampal neurons,and to elucidate the mechanism behind the ***:The antidepressant mechanism of luteolin was studied by using CUMS rat model and primary hippocampal neurons in fetal *** vivo,novelty suppressed feeding,open-field and sucrose preference tests as well as Morris water maze were *** content of brain derived neurotrophic factor(BDNF),5-hydroxytryptamine(5-HT),norepinephrine(NE),and dopamine(DA)in serum were detected by enzyme-linked immunosorbent *** mechanisms of luteolin were explored based on neurotrophin and hippocampal neurogenesis,and *** of the septotemporal axis in hippocampus was assayed using the 5-bromo-2-deoxyuridine(BrdU),the expression of BDNF,neurotrophin-3(NT-3),and nerve growth factor(NGF)in hippocampus dentate gyrus region were measured by *** vitro,BDNF,NT-3,tropomyosin receptor kinase B(TrkB),and phosphorylated cyclic adenosine monophosphate responsive element binding protein(p-CREB)were detected through the high content analysis(HCA)to investigate neurotrophin and ***:Induction of CUMS in rats induced depressive symptoms,while luteolin significantly enhanced sucrose consumption,decreased feeding latency,increased locomotor activity,escape latency,distance of target quadrant and regulated the content of depressive-like *** analysis revealed that luteolin increased the abundance of new born neurons that had been labeled with BrdU,BrdU+neuronal nuclear antigen,and BrdU+doublecortin in septo-temporal axis of S2(mid-septal)and T3(mid-temporal).Moreover,expression of BDNF,NT-3,and NGF increased significantly in the septo-temporal axis of S2 and *** showed increased expression of BDNF,NT-3,TrkB and p-CREB in primary hippocampal ***:The results provided direct ev

关键词： fetal rats Survival

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A new two-step variational model for multiplicative noise removal with applications to texture images

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Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 486-501页

作者： ZHANG long-hui YAO Wen-juan SHI Sheng-zhu GUO Zhi-chang ZHANG Da-zhi School of Mathematics Harbin Institute of TechnologyHarbin 150001China

Multiplicative noise removal problems have attracted much attention in recent *** additive noise,multiplicative noise destroys almost all information of the original image,especially for texture *** by the TV-Stokes model,we propose a new two-step variational model to denoise the texture images corrupted by multiplicative noise with a good geometry explanation in this *** the first step,we convert the multiplicative denoising problem into an additive one by the logarithm transform and propagate the isophote directions in the tangential field *** the isophote directions are constructed,an image is restored to fit the constructed directions in the second *** existence and uniqueness of the solution to the variational problems are *** these two steps,we use the gradient descent method and construct finite difference schemes to solve the ***,the augmented Lagrangian method and the fast Fourier transform are adopted to accelerate the *** results show that the proposed model can remove the multiplicative noise efficiently and protect the texture well.

关键词： multiplicative noise removal texture images total variation two-step variational method aug-mented Lagrangian method

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Intestinal flora: New perspective of type 2 diabetes

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World Journal of Clinical Cases 2024年第11期12卷 1996-1999页

作者： yan Liu Jun chang Li-Ding Bai Department of Gastroenterology Hospital of Integrated Chinese and Western MedicineTianjinTianjin 300100China First Teaching Hospital of Tianjin University of Traditional Chinese Medicine Tianjin 300381China Academy of Traditional Chinese Medicine Tianjin University of Traditional Chinese MedicineTianjin 300193China

Diabetes comprises a group of metabolic diseases characterized by hyperglycemia stemming from various *** diabetes management primarily focuses on blood glucose control,yet it is inherently progressive,necessitating increased reliance on exogenous blood glucose control methods over ***,there is an urgent need to explore novel intervention strategies addressing both diabetes and its *** human intestinal microbiota,often referred to as the"second genome",exhibits significant diversity and plays a pivotal role in insulin resistance,glucose and lipid metabolism,and inflammatory ***,Li and Guo have elucidated the involvement of intestinal flora in the pathogenesis of type 2 diabetes mellitus(T2DM)and proposed a novel therapeutic approach targeting intestinal *** advancement enhances our comprehension of the multifaceted and multi-target regulation of T2DM by intestinal microflora,thereby offering fresh avenues for understanding its pathogenesis and clinical *** letter briefly summarizes the role of intestinal flora in T2DM based on findings from animal experiments and clinical ***,it discusses the potential clinical applications and challenges associated with targeting intestinal flora as therapeutic interventions.

关键词： Microbial metabolites Intestinal flora Probiotics Insulin resistance Type 2 diabetes

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Design of artificial biomimetic channels with Na^(+)permeation rate and selectivity potentially outperforming the natural sodium channel

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Nano Research 2024年第9期17卷 8638-8646页

作者： Zhi Zhu yan Zhao Chao chang Shaojian yan Tingyu Sun Shiyu Gu yangmei Li Dengsong Zhang Chunlei Wang Xiao Cheng Zeng School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China Innovation Laboratory of Terahertz Biophysics National Innovation Institute of Defense TechnologyBeijing 100071China School of Physics Peking UniversityBeijing 100871China International Joint Laboratory of Catalytic Chemistry College of SciencesShanghai UniversityShanghai 200444China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China

Artificial ion channels that enable high-efficiency ion transport have important implications in nanofluidics and biomedical applications such as drug ***,we show a simulation-based chemical design of a biomimetic sodium channel that possesses permeation rate and selectivity potentially higher than those of the state-of-the-art natural vertebrate voltage-gated sodium ***,our theoretical findings have undergone empirical testing,aligning well with the Arrhenius law as derived from a diverse range of experimental *** high-efficiency ion transport is achieved by anchoring the carboxylate functional groups within the channel filter.A key chemical guiding principle underlying the ion channel design is that the free-energy barrier for the Na^(+)passage across the channel should be comparable to typical thermal energy at room *** the implementation of the chemical design,we found that the relatively low free-energy barrier can be attributed to the compensation effect of the carboxylate groups to the partially lost oxygen shell of the ion within the ion channel,as well as to the consonant vibration of the ions inside and outside the *** mechanistic understanding brings new insight,at the molecular level,into the high-efficiency ion transport across the designed membrane *** proof of principle achieved from the simulations will stimulate future experimental confirmation and potential applications of the high-performance artificial channels in nanofluidics and in bioinspired iontronics.

关键词： sodium channels anchoring carboxylate functional groups molecular dynamics simulations low free-energy barrier for ion passage thermal kinetic energy

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