621 research outputs found
PiCO QL: A software library for runtime interactive queries on program data
No full textAbstractPico ql is an open source c/c++ software whose scientific scope is real-time interactive analysis of in-memory data through sql queries. It exposes a relational view of a system’s or application’s data structures, which is queryable through sql. While the application or system is executing, users can input queries through a web-based interface or issue web service requests. Queries execute on the live data structures through the respective relational views. pico ql makes a good candidate for ad-hoc data analysis in applications and for diagnostics in systems settings. Applications of pico ql include the Linux kernel, the Valgrind instrumentation framework, a gis application, a virtual real-time observatory of stellar objects, and a source code analyser
Null-space-based optimal control reallocation for spacecraft stabilization under input saturation
No full textA novel saturated proportional-derivative control incorporated with null-space-based optimal control reallocation is proposed for spacecraft attitude stabilization in the presence of disturbance and input saturation. More specifically, a saturated proportional-derivative based baseline nonlinear controller is firstly developed to guarantee the globally asymptotic stability under input constraints and external disturbance. This is achieved with inexpensive online computations by dynamically adjusting a single parameter to ensure the desired performance. Then, a novel null-space-based optimal control reallocation method is employed to map the specified virtual control command to the redundant actuators. The optimal control solution is obtained by penalizing the control allocation errors at a lower power/energy cost using quadratic programming algorithm. The benefits of the proposed control method are analytically authenticated and also validated via simulation study
Lignin bioconversion based on genome mining for ligninolytic genes in Erwinia billingiae QL-Z3
No full textAbstract Background Bioconversion of plant biomass into biofuels and bio-products produces large amounts of lignin. The aromatic biopolymers need to be degraded before being converted into value-added bio-products. Microbes can be environment-friendly and efficiently degrade lignin. Compared to fungi, bacteria have some advantages in lignin degradation, including broad tolerance to pH, temperature, and oxygen and the toolkit for genetic manipulation. Results Our previous study isolated a novel ligninolytic bacterial strain Erwinia billingiae QL-Z3. Under optimized conditions, its rate of lignin degradation was 25.24% at 1.5 g/L lignin as the sole carbon source. Whole genome sequencing revealed 4556 genes in the genome of QL-Z3. Among 4428 protein-coding genes are 139 CAZyme genes, including 54 glycoside hydrolase (GH) and 16 auxiliary activity (AA) genes. In addition, 74 genes encoding extracellular enzymes are potentially involved in lignin degradation. Real-time PCR quantification demonstrated that the expression of potential ligninolytic genes were significantly induced by lignin. 8 knock-out mutants and complementary strains were constructed. Disruption of the gene for ELAC_205 (laccase) as well as EDYP_48 (Dyp-type peroxidase), ESOD_1236 (superoxide dismutase), EDIO_858 (dioxygenase), EMON_3330 (monooxygenase), or EMCAT_3587 (manganese catalase) significantly reduced the lignin-degrading activity of QL-Z3 by 47–69%. Heterologously expressed and purified enzymes further confirmed their role in lignin degradation. Fourier transform infrared spectroscopy (FTIR) results indicated that the lignin structure was damaged, the benzene ring structure and groups of macromolecules were opened, and the chemical bond was broken under the action of six enzymes encoded by genes. The abundant enzymatic metabolic products by EDYP_48, ELAC_205 and ESOD_1236 were systematically analyzed via liquid chromatography–mass spectrometry (LC–MS) analysis, and then provide a speculative pathway for lignin biodegradation. Finally, The activities of ligninolytic enzymes from fermentation supernatant, namely, LiP, MnP and Lac were 367.50 U/L, 839.50 U/L, and 219.00 U/L by orthogonal optimization. Conclusions Our findings provide that QL-Z3 and its enzymes have the potential for industrial application and hold great promise for the bioconversion of lignin into bioproducts in lignin valorization
Disturbance observer based finite-time attitude control for rigid spacecraft under input saturation
No full textA novel finite-time controller integrated with disturbance observer is investigated for a rigid spacecraft in the presence of disturbance, actuator saturation and misalignment. As a stepping-stone, a second-order disturbance observer is designed firstly such that the reconstruction of lumped disturbances is accomplished in finite time with zero error. Then, with the reconstructed information, a finite-time controller is synthesized even under actuator input saturation and misalignment, and the closed-loop system/state is proved to be finite-time stable and converges to the specified time-varying sliding mode surface. Moreover, the input saturation constraint is overcome via introducing an auxiliary variable to compensate for the overshooting. Numerical simulation results for the in-orbit rigid spacecraft show good performances, which validate the effectiveness and feasibility of the proposed schemes
Penglai zircon: A potential new reference for microbeam analysis of U-Pb age and O-Hf isotopes
No full textSilver nanoparticle-induced hemoglobin decrease involves alteration of histone 3 methylation status
No full textSilver nanoparticles (nanosilver, AgNPs) have been shown to induce toxicity in vitro and in vivo; however, the molecular bases underlying the detrimental effects have not been thoroughly understood. Although there are numerous studies on its genotoxicity, only a few studies have investigated the epigenetic changes, even less on the changes of histone modifications by AgNPs. In the current study, we probed the AgNP-induced alterations to histone methylation that could be responsible for globin reduction in erythroid cells. AgNP treatment caused a significant reduction of global methylation level for histone 3 (H3) in erythroid MEL cells at sublethal concentrations, devoid of oxidative stress. The ChIP-PCR analyses demonstrated that methylation of H3 at lysine (Lys) 4 (H3K4) and Lys 79 (H3K79) on the beta-globin locus was greatly reduced. The reduction in methylation could be attributed to decreased histone methyltransferase DOT-1L and MLL levels as well as the direct binding between AgNPs to H3/H4 that provide steric hindrance to prevent methylation as predicted by the all-atom molecular dynamics simulations. This direct interaction was further proved by AgNP-mediated pull-down assay and immunoprecipitation assay. These changes, together with decreased RNA polymerase II activity and chromatin binding at this locus, resulted in decreased hemoglobin production. By contrast, Ag ion-treated cells showed no alterations in histone methylation level. Taken together, these results showed a novel finding in which AgNPs could alter the methylation status of histone. Our study therefore opens a new avenue to study the biological effects of AgNPs at sublethal concentrations from the perspective of epigenetic mechanisms. (C) 2015 Elsevier Ltd. All rights reserved
BIỆN PHÁP TĂNG CƯỜNG ỨNG DỤNG CÔNG NGHỆ THÔNG TIN TRONG QUẢN LÝ HOẠT ĐỘNG KHOA HỌC – CÔNG NGHỆ TẠI ĐẠI HỌC HUẾ
No full textHiện nay, công nghệ thông tin (CNTT) đang phát triển mạnh mẽ và được đánh giá không chỉ là động lực chủ yếu cho việc phát triển kinh tế, xã hội mà còn là nhân tố quan trọng trong việc phát triển giáo dục và đào tạo (GD-ĐT). Ứng dụng CNTT vào quản lý và điều hành nói chung và quản lý (QL) hoạt động Khoa học - Công nghệ (KH-CN) tại Đại học Huế (ĐHH) nói riêng đang trở thành một nhu cầu tất yếu và đang được cán bộ quản lý (CB QL), giảng viên (GV) tích cực triển khai và ứng dụng. Xác lập được các biện pháp QL ứng dụng CNTT trong QL hoạt động KH-CN tại ĐHH một cách khoa học, đồng bộ sẽ góp phần nâng cao hiệu quả, chất lượng QL hoạt động KH-CN tại ĐHH đáp ứng yêu cầu đổi mới GD-ĐT trong giai đoạn hiện nay
Effects of graphene oxide nanosheets on the ultrastructure and biophysical properties of the pulmonary surfactant film
No full textGraphene oxide (GO) is the most common derivative of graphene and has been used in a large range of biomedical applications. Despite considerable progress in understanding its cytotoxicity, its potential inhalation toxicity is still largely unknown. As the pulmonary surfactant (PS) film is the first line of host defense, interaction with the PS film determines the fate of the inhaled nanomaterials and their potential toxicity. Using a coarse-grained molecular dynamics model, we reported, for the first time, a novel mechanism of toxicity caused by the inhaled GO nanosheets. Upon deposition, the GO nanosheets induce pores in the PS film and thus have adverse effects on the ultrastructure and biophysical properties of the PS film. Notably, the pores induced by GO nanosheets result in increasing the compressibility of the PS film, which is an important indication of surfactant inhibition. In vitro experiments have also been conducted to study the interactions between GO and animal-derived natural PS films, qualitatively confirming the simulation results
A novel plasmid carrying carbapenem-resistant gene blaKPC-2 in Pseudomonas aeruginosa
No full textYan-Yan Hu, Qi Wang, Qiao-Ling Sun, Gong-Xiang Chen, Rong Zhang2nd Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, People’s Republic of ChinaAbstract: A carbapenem-resistant Pseudomonas aeruginosa strain PA1011 (ST463) was isolated from a patient in a surgical intensive care unit. PCR detection showed that PA1011 carried the blaKPC-2 gene. A plasmid was isolated and sequenced using the Illumina NextSeq 500 and PacBio RSII sequencing platforms. The plasmid was named pPA1011 and carried the carbapenem-resistant gene blaKPC-2. pPA1011 was a 62,793 bp in length with an average G+C content of 58.8%. It was identified as a novel plasmid and encoded a novel genetic environment of blaKPC-2 gene (ΔIS6-Tn3-ISKpn8-blaKPC-2-ISKpn6-IS26).Keywords: plasmid, genetic environment, KPC, ST463, Pseudomonas aeruginos
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