Rust is a relatively new programming language that targets efficient and safe systems-level applications. It includes a sophisticated type system that allows for provable memory- and thread-safety, and is explicitly d...
详细信息
Rust is a relatively new programming language that targets efficient and safe systems-level applications. It includes a sophisticated type system that allows for provable memory- and thread-safety, and is explicitly designed to take the place of unsafe languages such as c and c++ in the coding ecosystem. There is a large existing c and c++ codebase (many of which have been affected by bugs and security vulnerabilities due to unsafety) that would benefit from being rewritten in Rust to remove an entire class of potential bugs. However, porting these applications to Rust manually is a daunting task. In this paper we investigate the problem of automatically translating c programs into safer Rust programs- that is, Rust programs that improve on the safety guarantees of the original c programs. We conduct an in-depth study into the underlying causes of unsafety in translated programs and the relative impact of fixing each cause. We also describe a novel technique for automatically removing a particular cause of unsafety and evaluate its effectiveness and impact. This paper presents the first empirical study of unsafety in translated Rust programs (as opposed to programs originally written in Rust) and also the first technique for automatically removing causes of unsafety in translated Rust programs.
Two-dimensional layered semiconducting materials, such as tungsten disulfide, have attracted significant research interest over the past few decades. With rational optimization of their chemical constitutions and regu...
详细信息
Two-dimensional layered semiconducting materials, such as tungsten disulfide, have attracted significant research interest over the past few decades. With rational optimization of their chemical constitutions and regulation of electronicconfigurations, these materials can achieve commercial viability. Herein, the WS2/c hybrid was constructed by organic amine intercalation and in-situ pyrolysis. Intraparticle porous WS2/c was successfully synthesized by dissolving and etching. The specific surface area of the obtained WS2/c was significantly enhanced on the removal of WO3 through alkali etching, which facilitated the Na-insertion/ extraction. Therefore, the obtained porous WS2/ccomposite delivered a high reversible capacity and improved cycle stability with 346.3 mAh g-1 over 80 cycles at 100 mA g-1. This work proposes an intragranular porous WS2/ccomposite electrode design which shows a superior sodium storage performance, improved electronicconductivity and enhanced reversible specificcapacity. It is expected to present a novel insight for designing other high-capacity sodium-ion and other alkaline ion battery electrode materials.
Aging animals accumulate insoluble proteins as a consequence of a decline of proteostatic maintenance with age. In caenorhabditis elegans, for instance, levels of detergent-insoluble proteins increase with age. In lon...
详细信息
Aging animals accumulate insoluble proteins as a consequence of a decline of proteostatic maintenance with age. In caenorhabditis elegans, for instance, levels of detergent-insoluble proteins increase with age. In longer-lived strains of c. elegans, this accumulation occurs more slowly, implying a link to lifespan determination. We further explored this link and found that detergent-insoluble proteins accumulate more rapidly at higher temperatures, a condition where lifespan is short. We employed a c. elegans strain carrying a GFP transcriptional reporter under the control of a heat shock (hsp-16.2) promoter to investigate the dynamics of proteostatic failure in individual nematodes. We found that early, sporadic activation of hsp-16.2 was predictive of shorter remaining lifespan in individual nematodes. Exposure to rapamycin, resulting in reduced mTOR signaling, delayed spurious expression, extended lifespan, and delayed accumulation of insoluble proteins, suggesting that targets downstream of the mTOR pathway regulate the accumulation of insoluble proteins. We specifically explored ribosomal S6 kinase (rsks-1) as one such candidate and found that RNAi against rsks-1 also resulted in less age-dependent accumulation of insoluble proteins and extended lifespan. Our results demonstrate that inhibition of protein translation via reduced mTOR signaling resulted in slower accumulation of insoluble proteins, delayed proteostaticcrisis, and extended lifespan in c. elegans.
c/Siccomposites prepared by polymer infiltration and pyrolysis (PIP) are among the most promising materials for application in ultrahigh-temperature conditions. However, the mechan-ical properties and damage mechanis...
详细信息
c/Siccomposites prepared by polymer infiltration and pyrolysis (PIP) are among the most promising materials for application in ultrahigh-temperature conditions. However, the mechan-ical properties and damage mechanisms of PIP-c/Siccomposites at different loading velocities and temperatures have not been systematically studied. In this study, in-plane compression, bending, and in-plane shear experiments were systematically performed at different loading ve-locities and temperatures in an inert atmosphere. The ultimate strengths of the PIP-c/Siccom-posite were determined under different conditions, and the failure modes were revealed. In addition, in-situ X-ray microtomography tension experiments were conducted to study the failure mechanism of the PIP-c/Siccomposite. The results showed that the ultimate strengths were considerably affected by the temperature and loading velocity, and the failure modes were dependent on experimental types. The fracture location of the PIP-c/Siccomposite is affected by the defect. And the direction of crack propagation is toward the existing cracks and voids.
In this study, the biodegradation of phenanthrene was investigated in newly isolated endophytic fungal strains, Fusarium sp. (KTS01), Trichoderma harzianum (LAN03), Fusarium oxysporum (KTS02), Fusarium oxysporum (LAN0...
详细信息
In this study, the biodegradation of phenanthrene was investigated in newly isolated endophytic fungal strains, Fusarium sp. (KTS01), Trichoderma harzianum (LAN03), Fusarium oxysporum (KTS02), Fusarium oxysporum (LAN04), and clonostachys rosea (KTS05). This was performed under different carbon:nitrogen ratios (10:1, 20:1, and 30:1) using different nitrogen sources (urea and malt extract and ammonium nitrate) over a 30 d incubation period in both static and agitated liquid media. The kinetics of polycyclic aromatic hydrocarbons (PAH) min-eralisation to cO2 (lag phases, fastest rates, and overall extents) were measured for all of the fungal strains and nutrient conditions using 14c-phenanthrene. All fungal strains were able to biodegrade 14c-phenanthrene to 14cO2 under the different nutrient amendments. However, 14c-phenanthrene mineralisation varied for most of the fungal strains in static and agitated culture conditions. Greater extents of mineralisation were found in fungal cultures (strains KTS05 and KTS01) with c:N ratio of 10:1 in both static and agitated conditions, while the fungal strains (KTS05 and LAN03) showed the greatest phenanthrene mineralisation after N source amendments, particularly with malt extract. In addition, the phenanthrene mineralisation increased with higher c:N ratios for clonostachys rosea (KTS05) only. consequently, the results reported here provide a promising potential for the endophytic fungal strains and the importance of nutrients amendments for the enhanced degradation of PAHs contaminated environments.
Hierarchical dumbbell-like Fe3O4/c powder was synthesized for the supercapacitor electrode by the sol-vothermal reaction and subsequent calcination. Resultantly, the reversible capacitances of the three-electrode and ...
详细信息
Hierarchical dumbbell-like Fe3O4/c powder was synthesized for the supercapacitor electrode by the sol-vothermal reaction and subsequent calcination. Resultantly, the reversible capacitances of the three-electrode and symmetric two-electrode capacitors were 490.2 F/g and 210.2 F/g, respectively, higher than those in lit-eratures, possibly due to the unique hierarchical dumbbell-like structure with the easier access and penetration of the electrolyte to the electrode. Moreover, the symmetric Fe3O4/c two-electrode system exhibited the remark-able cycle stability at 5.0 A/g and high energy density of 34.3 Wh/kg at 1003.9 W/kg, indicating high feasibility for the application in high-performance supercapacitor.
c/SiBcN composites are expected to be widely used in aerospace applications because of their excellent high-temperature stability. However, the interfacial reactions have significantly limited their practical applicat...
详细信息
c/SiBcN composites are expected to be widely used in aerospace applications because of their excellent high-temperature stability. However, the interfacial reactions have significantly limited their practical application. A pyrocarbon (Pyc) interphase can improve the interfacial reactions of c/SiBcN composites. In this study, Pyc interphases of different thicknesses (0.1 mu m, 0.25 mu m, and 0.5 mu m) were introduced via chemical vapor deposition (cVD) process. The interface bonding of c/SiBcN composites with 0.1 mu m and 0.25 mu m thick interphases was relatively weak and the composites with 0.5 mu m interphase exhibited strong interface bonding. After heat treatment at 1600 degrees c, the mechanical properties of the c/SiBcN composites with the 0.5 mu m thick interphase was maintained at 131 MPa, and it was maintained at 105 MPa even after heat treatment at 1900 degrees c, indicating their excellent high-temperature mechanical properties. In short, 0.5 mu m thick Pyc interphase can effectively improve the interfacial reaction of the c/SiBcN composites, facilitating their application in high-temperature environments.
Mutation of cytochrome c in humans causes mild autosomal dominant thrombocytopenia. The role of cytochrome c in platelet formation, and the molecular mechanism underlying the association of cytochrome c mutations with...
详细信息
Mutation of cytochrome c in humans causes mild autosomal dominant thrombocytopenia. The role of cytochrome c in platelet formation, and the molecular mechanism underlying the association of cytochrome c mutations with thrombocytopenia remains unknown, although a gain-of-function is most likely. cytochrome ccontributes to several cellular processes, with an exchange between conformational states proposed to regulate changes in function. Here, we use experimental and computational approaches to determine whether pathogenic variants share changes in structure and function, and to understand how these changes might occur. Three pathogenic variants (G41S, Y48H, A51V) cause an increase in apoptosome activation and peroxidase activity. Molecular dynamics simulations of these variants, and two non-naturally occurring variants (G41A, G41T), indicate that increased apoptosome activation correlates with the increased overall flexibility of cytochrome c, particularly movement of the S2 loops. crystal structures of Y48H and G41T complement these studies which overall suggest that the binding of cytochrome c to apoptotic protease activating factor-1 (Apaf-1) may involve an 'induced fit' mechanism which is enhanced in the more conformationally mobile variants. In contrast, peroxidase activity did not significantly correlate with protein dynamics. Thus, the mechanism by which the variants increase peroxidase activity is not related to the conformational dynamics of the native hexacoordinate state of cytochrome c. Recent molecular dynamics data proposing conformational mobility of specificcytochrome c regions underpins changes in reduction potential and alkaline transition pK was not fully supported. These data highlight that conformational dynamics of cytochrome c drive some but not all of its properties and activities.
Abrus mollis is commonly used as a traditional chinese medicine for the treatment of liver diseases due to its hepatoprotection and anti-inflammation, but the absorption properties of its main bioactive ingredients re...
详细信息
Abrus mollis is commonly used as a traditional chinese medicine for the treatment of liver diseases due to its hepatoprotection and anti-inflammation, but the absorption properties of its main bioactive ingredients remain unclear. Our previous studies verified that the flavonoid c -glycosides, including vicenin-2 ( 1 ), isoschaftoside ( 2 ), and schaftoside ( 3 ), were the major active components in A. mollis for hepatic protection against nonalcoholic fatty liver disease, hepatitis, and hepatic fibrosis. This study investigated the bioaccessibility and transport mechanisms of total flavonoid c -glycoside, as well as vicenin-2 ( 1 ), isoschaftoside ( 2 ), and schaftoside ( 3 ), in A. mollis by simulated digestion and use of the caco-2 cell model. Moreover, this study attempted to verify their absorption properties by in situ gastrointestinal perfusion in rats. Total flavonoid c -glycoside and 1, 2 , and 3 exhibited similar bioaccessibility of 84.58%, 85.13%, 83.05%, and 81.65% respectively after simulated digestion. The transport of total flavonoid c -glycoside in the caco-2 cell model increased with the concentration, and the transport showed saturation characteristics with the time and concentration of total flavonoid c -glycoside to a certain degree. The Papp values of total flavonoid c -glycoside and the 3 flavonoid c -glycosides were significantly improved by verapamil, probenecid, and EDTA-Na (2) . Their absorption properties in the gastrointestinal tract were consistent with that found in caco-2 cells, and superior absorption rates were observed in the duodenum and jejunum. The absorption pattern of total flavonoid c -glycoside may involve multiple transport pathways, including active transport, passive diffusion, and the paracellular pathway. TFc was actively pumped out by P-glycoprotein and multidrug resistance-associated protein. These results revealed that the bioaccessibility and intestinal absorption characteristic of total flavonoid c -glycoside were c
暂无评论