This article presents the formal verification, using the coq proof assistant, of a memory model for low-level imperative languages such as c and compiler intermediate languages. Beyond giving semantics to pointer-base...
详细信息
This article presents the formal verification, using the coq proof assistant, of a memory model for low-level imperative languages such as c and compiler intermediate languages. Beyond giving semantics to pointer-based programs, this model supports reasoning over transformations of such programs. We show how the properties of the memory model are used to prove semantic preservation for three passes of the compcert verified compiler.
Background Helicobacter pylori (H. pylori) infect more than half of the world population, and they cause different serious diseases such as gastriccarcinomas. This study aims to design a vaccine on the basis of cagW ...
详细信息
Background Helicobacter pylori (H. pylori) infect more than half of the world population, and they cause different serious diseases such as gastriccarcinomas. This study aims to design a vaccine on the basis of cagW against H. pylori infection. After pcDNA3.1 (+)-cagW-cS-NPs complex is produced, it will be administered into the muscles of healthy BALB/c mice in order to study the effect of this DNA vaccine on the interleukin status of mice, representing its effect on the immune system. After that, the results will be compared with the control groups comprising the administration of cagW-pcDNA3.1 (+) vaccine, the administration of chitosan and the administration of PBS in the muscles of mice. Methods The cagW gene of H. pylori was amplified by employing PcR, whose product was then cloned into the pcDNA3.1 (+) vector, and this cloning was confirmed by PcR and BamHI/EcoRV restriction enzyme digestion. cagW gene DNA vaccine was encapsulated in chitosan nanoparticles (pcDNA3.1 (+)-cagW-cS-NPs) using a complex coacervation method. The stability and in vitro expression of chitosan nanoparticles were studied by DNase I digestion and transfection, and the immune responses elicited in specific pathogen-free (SPF) mice by the pcDNA3.1 (+)-cagW-cS-NPs were evaluated. Apart from that, the protective potential pcDNA3.1 (+)-cagW-cS-NPs was evaluated by challenging with H. pylori. Results The pcDNA3.1 (+)-cagW-cS-NPs comprises cagW gene of H. pylori that is encapsulated in chitosan nanoparticles, produced with good morphology, high stability, a mean diameter of 117.7 nm, and a zeta potential of + 5.64 mV. Moreover, it was confirmed that chitosan encapsulation protects the DNA plasmid from DNase I digestion, and the immunofluorescence assay showed that the cagW gene could express in HDF cells and maintain good bioactivity at the same time. In comparison to the mice immunized with the control plasmid, in vivo immunization revealed that mice immunized with pcDNA3.1 (+)-cagW-NPs showe
The selective adsorption mechanism of c-cdS2 2 monolayer was revealed using density functional theory. The results show that c-cdS2 2 has good adsorption properties for SO2, 2 , NO, NH3, 3 , NO2 2 and cl2, 2 , and all...
详细信息
The selective adsorption mechanism of c-cdS2 2 monolayer was revealed using density functional theory. The results show that c-cdS2 2 has good adsorption properties for SO2, 2 , NO, NH3, 3 , NO2 2 and cl2, 2 , and all of them are chemisorbed. Under the adsorption of different gas molecules, the electronic structure of c-cdS2 2 changed to varying degrees, which provided a theoretical basis for the use of c-cdS2 2 as a gas sensor or scavenger for these gases.
Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is propo...
详细信息
Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is proposed for the first time to optimize the characteristics of NVP. The introduction of Nb5+ generates beneficial carriers and vacancies that optimize the electronic structure of NVP system. Meanwhile, rGO substrate can construct an effective conductive network for the facilitated electronic transportation and form a stabilized SEI layer after cycling to protect the active particles from being collapsed. This double treatment significantly improves the kineticcharacteristics of NVP. Moreover, theoretical calculations indicate that beneficial Nb5+ doping can effectively reduce the band gap between conductive and valence bands, as well as decline the energy barrier of migration for Na+. Notably, the modified Nb0.15-NVP/c@rGO exhibits impressive electrochemical performance. It delivers a capacity of 107.9 mAh g-1 and keeps a value of 102.6 mAh g-1 after 500 cycles at 2c with a high retention of 95.35%. It submits a capacity value of 97.2 mAh g-1 at 20c, 82.92% reversible capacity (80.6 mAh g-1) could be retained after 2000 cycles. Even at 120 and 300c, this material still performs high values of 84.9 and 71.3 mAh g-1, indicating the superior rate capability.
Microsoft's next-generation platform, the NET Framework, offers a new language, c#, which aims to offer the power of c++ with the ease of Visual Basic. In this article, the authors consider the application of c# a...
详细信息
Microsoft's next-generation platform, the NET Framework, offers a new language, c#, which aims to offer the power of c++ with the ease of Visual Basic. In this article, the authors consider the application of c# and the NET Framework to real-time systems. Their performance tests show that c and c# performance is comparable in some cases. However, they show that c# is not currently suitable for hard real-time applications and should be used for firm and soft real-time applications only with care.
The potential catalytic activity of selected c,N-chelated organotin(IV) compounds (e.g. halides and trifluoroacetates) for derivatization of both dimethyl carbonate (DMc) and diethyl carbonate (DEc) was investigated. ...
详细信息
The potential catalytic activity of selected c,N-chelated organotin(IV) compounds (e.g. halides and trifluoroacetates) for derivatization of both dimethyl carbonate (DMc) and diethyl carbonate (DEc) was investigated. Some tri-, di- and monoorganotin(IV) species (LcN(n-Bu)2Sncl (1), LcN(n-Bu)*** (1a), LcN(n-Bu)2SnI (2), LcNPh2Sncl (3), LcNPh2SnI (4), LcN(n-Bu)Sncl2 (5), LcNSnBr3 (6) and [LcNSn(Oc(O)cF3)]2(mu-O)(mu-Oc(O)cF3)2 (7)) bearing the LcN moiety (LcN?=?2-(N,N-dimethylaminomethyl)phenyl-) were assessed as catalysts for reactions of both DMc and DEc with various substituted anilines. The catalytic activities of 4 and 7 for derivatization of DMc with p-substituted phenols were studied for comparison with the standard base K2cO3/Silcarbon K835 catalyst (catalyst 8). The composition of resulting reaction mixtures was monitored by multinuclear NMR spectroscopy, Gc and Gc-MS techniques. In general, catalysts 1, 3 and 7 exhibited the highest catalytic activity for all reactions studied, while some of them yielded selectively carbonates, carbamates, lactam or substituted urea. copyright (c) 2012 John Wiley & Sons, Ltd.
A LiFePO4/c material with different amounts of iron phosphides was synthesized by a sol-gel method with different calcination temperatures. XRD, HRTEM, SEM, FTIR, BET, Raman, and magnetic measurements were carried out...
详细信息
A LiFePO4/c material with different amounts of iron phosphides was synthesized by a sol-gel method with different calcination temperatures. XRD, HRTEM, SEM, FTIR, BET, Raman, and magnetic measurements were carried out to characterize the physical properties of the LiFePO4/c, while EIS, cV, and charge-discharge tests were carried out to characterize the electrochemical performance. It is obtained that the crystallinity, the particle size of the LiFePO4, and the amount of iron phosphides in the sample are the factors that affect the electrochemical performance of the material, where the key factor determining the electrochemical performance varies in different situations. The samples possessing well-crystallized LiFePO4 particles and similar particle size demonstrated improved rate performance with the increasing amount of iron phosphides when the calcination temperature increased from 650 to 750 degrees c. The results showed that the rate performance could be improved by harmonious improvement of the ionicconductivity of Li+ and the electronicconductivity.
Dystrophin-like dys-1 gene is expressed and required in muscle tissue, playing a vital role in gravisensing in caenorhabditis elegans (c. elegans). To date, microRNA (miRNA)-mediated epigenetic mechanism in microgravi...
详细信息
Dystrophin-like dys-1 gene is expressed and required in muscle tissue, playing a vital role in gravisensing in caenorhabditis elegans (c. elegans). To date, microRNA (miRNA)-mediated epigenetic mechanism in microgravity-induced muscular atrophy remains to be elucidated. In the present study, we first analyzed mRNA and miRNA expression profiles in space-flown dys-1(cx18) mutants and wild type worms (wt) of c. elegans. The results showed that spaceflight and microgravity have fewer effects on mRNA and miRNA expression in dys-1 mutant than in wt worms. mRNA and miRNA expression patterns of dys-1 mutants were changed by microgravity. Hierarchical clustering analysis showed that the alterations of genes function on neuromuscular system under space environment. Seven miRNAs (cel-miR-52, 56, 81, 82, 84, 124 and 230) have 18 significant anti-correlated target genes under space environment. RT-qPcR analysis confirmed that miR-52 and cdh-3, miR-84 and lin-14, miR-124 and mgl-3 in dys-1 mutants reversely altered under microgravity environment and in simulated microgravity experiment. Locomotion ability was only reduced in F0 wt worms but not in dys-1 mutants as well as their F1 offspring after simulated microgravity. We observed expression alterations of 7 neuromuscular genes (unc-27, nlp-22, flp-1, egl-5, flp-4, mgl-3, unc-94) in F0 wt worms, which might be involved in the regulation of locomotion ability of c. elegans. This study provides important insights to reveal the mechanism in the pathogenesis of muscular atrophy induced by microgravity.
Poor thermal conductivity, especially in thickness direction, is a major obstacle to extend the service lifetime of c/Siccomposite. However, there are few papers focusing on finely designing heat conductive channel b...
详细信息
Poor thermal conductivity, especially in thickness direction, is a major obstacle to extend the service lifetime of c/Siccomposite. However, there are few papers focusing on finely designing heat conductive channel but a simply introduction of various modifiers to improve c/Sic thermal conductivity, which leads to less success. Herein, multi-layer graphene sheets were utilized to improve the thermal conductivity of c/Siccomposites via an effective method to design graphene heat conductive channels. To determine the role of graphene sheets in improving thermal conductivity, the effect of the different loading fractions of graphene and microstructure of as-prepared composites were systemically investigated. Results revealed that the thermal conductivity of composites increased by 204% with well-designed graphene heat conductive channels. Besides, compared with the porosity, the orderly aligned heat conductive pathways played a more important role in thermal conductivity. This work provides a new and effective method for preparing well-designed heat conductive channels to enhance thermal conductivity of c/Sic.
The electrical properties of c/Siccomposites could be used for online and in-situ damage monitoring. To investigate alternating current (Ac) impedance response to damage in the c/Siccomposites, monotonic and increme...
详细信息
The electrical properties of c/Siccomposites could be used for online and in-situ damage monitoring. To investigate alternating current (Ac) impedance response to damage in the c/Siccomposites, monotonic and incremental cyclic tensile tests were performed. Both Ac impedance and acoustic emission (AE) techniques were applied to clarify the damage evolution during the tests. The relationship between damage and electrical impedance response was investigated and validated via macroscopic equivalent circuit models. The effects of longitudinal deformation and damage on Ac impedance characteristics, including impedance magnitude and phase angle, were obtained from the models. Results showed that the longitudinal deformation increases the impedance magnitude and the phase angle, and the damage causes the impedance magnitude to increase and the phase angle to decrease. The phase angle is significantly sensitive to fiber breakage, which makes the Ac-based method more suitable for online damage monitoring and final failure warning.
暂无评论