3,444 research outputs found

    The Role of Chaos in One-Dimensional Heat Conductivity

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    We investigate the heat conduction in a quasi 1-D gas model with various degree of chaos. Our calculations indicate that the heat conductivity Îș\kappa is independent of system size when the chaos of the channel is strong enough. The different diffusion behaviors for the cases of chaotic and non-chaotic channels are also studied. The numerical results of divergent exponent α\alpha of heat conduction and diffusion exponent ÎČ\beta are in consistent with the formula α=2−2/ÎČ\alpha=2-2/\beta. We explore the temperature profiles numerically and analytically, which show that the temperature jump is primarily attributed to superdiffusion for both non-chaotic and chaotic cases, and for the latter case of superdiffusion the finite-size affects the value of ÎČ\beta remarkably.Comment: 6 pages, 7 figure

    Ekspresija tanaze iz plijesni Aspergillus oryzae u kvascu Pichia pastoris i primjena u sintezi propil galata u organskom otapalu

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    Gallic acid esters could be synthesized biologically by tannase in organic media, among which is propyl gallate, an antioxidant widely used as a food additive. Efficient intracellular expression of Aspergillus oryzae tannase was achieved in Pichia pastoris under the control of the AOX1 promoter, and the productivity of recombinant tannase was 960 U/L or 64 U/g dry mass. The recombinant P. pastoris was used to synthesize propyl gallate in organic solvent and the yield of propyl gallate was 53 %.Esteri galne kiseline, poput propil galata, antioksidansa koji se često koristi kao prehrambeni aditiv, mogu se bioloơki sintetizirati pomoću tanaze u organskom otapalu. Postignuta je uspjeơna intracelularna ekspresija tanaze iz plijesni Aspergillus oryzae u kvascu Pichia pastoris pod kontrolom promotora AOX1, kao i prinos rekombinantne tanaze od 960 U/L ili 64 U/g suhe tvari. Rekombinantni soj P. pastoris upotrijebljen je za sintezu propil galata u organskom otapalu, pri čemu je postignut prinos propil galata od 53 %

    Medium effects on the selection of sequences folding into stable proteins in a simple model

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    We study the medium effects on the selection of sequences in protein folding by taking account of the surface potential in HP-model. Our analysis on the proportion of H and P monomers in the sequences gives a direct interpretation that the lowly designable structures possess small average gap. The numerical calculation by means of our model exhibits that the surface potential enhances the average gap of highly designable structures. It also shows that a most stable structure may be no longer the most stable one if the medium parameters changed.Comment: 4 pages, 4 figure

    Lateral load bearing characteristics of light gauge steel and lightweight concrete shear walls

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    In China, there is a new structural system named light gauge steel and lightweight concrete (LSLC) structure, which used lightweight concrete as structural material in composite way with cold-formed steel. Here, the shear walls are the main structural members for the LSLC structure, which are assembled with the light gauge steel lattice columns and horizontal braces, and filled with lightweight concrete. In this study, the LSLC shear walls are experimentally investigated to evaluate their failure mechanism and lateral load bearing capacity. For this purpose, several specimens with different shear span ratio are designed and tested under static cyclic loading. This paper presents the damage state and hysteresis loops of the specimens detailly. Then, the lateral load bearing characteristics of the LSLC shear walls are discussed according to the failure mechanism, such as shear and flexural failure. Finally, the calculation methods of lateral strength for the LSLC shear walls are proposed based on the diagonal strut mechanism and sectional force equilibrium

    Genome plasticity and systems evolution in Streptomyces

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    Background Streptomycetes are filamentous soil-dwelling bacteria. They are best known as the producers of a great variety of natural products such as antibiotics, antifungals, antiparasitics, and anticancer agents and the decomposers of organic substances for carbon recycling. They are also model organisms for the studies of gene regulatory networks, morphological differentiation, and stress response. The availability of sets of genomes from closely related Streptomyces strains makes it possible to assess the mechanisms underlying genome plasticity and systems adaptation. Results We present the results of a comprehensive analysis of the genomes of five Streptomyces species with distinct phenotypes. These streptomycetes have a pan-genome comprised of 17,362 orthologous families which includes 3,096 components in the core genome, 5,066 components in the dispensable genome, and 9,200 components that are uniquely present in only one species. The core genome makes up about 33%-45% of each genome repertoire. It contains important genes for Streptomyces biology including those involved in gene regulation, secretion, secondary metabolism and morphological differentiation. Abundant duplicate genes have been identified, with 4%-11% of the whole genomes composed of lineage-specific expansions (LSEs), suggesting that frequent gene duplication or lateral gene transfer events play a role in shaping the genome diversification within this genus. Two patterns of expansion, single gene expansion and chromosome block expansion are observed, representing different scales of duplication. Conclusions Our results provide a catalog of genome components and their potential functional roles in gene regulatory networks and metabolic networks. The core genome components reveal the minimum requirement for streptomycetes to sustain a successful lifecycle in the soil environment, reflecting the effects of both genome evolution and environmental stress acting upon the expressed phenotypes. A better understanding of the LSE gene families will, on the other hand, bring a wealth of new insights into the mechanisms underlying strain-specific phenotypes, such as the production of novel antibiotics, pathogenesis, and adaptive response to environmental challenges

    Bloqueio contĂ­nuo do nervo femoral guiado por ultrassom e estimulador de nervo para analgesia apĂłs artroplastia total de joelho: estudo multicĂȘntrico, randomizado e controlado

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    ResumoJustificativa e objetivosAnalgesia pĂłs‐operatĂłria Ă© fundamental para o exercĂ­cio funcional precoce logo apĂłs a artroplastia total de joelho. O objetivo foi investigar a eficĂĄcia clĂ­nica do bloqueio contĂ­nuo do nervo femoral guiado por ultrassom e estimulador de nervo em analgesia apĂłs artroplastia total do joelho.MĂ©todosReceberam analgesia pĂłs‐operatĂłria, de outubro de 2012 a janeiro de 2013, 46 pacientes, estado fĂ­sico ASA I‐III, submetidos Ă  artroplastia total de joelho. Em 22 pacientes, o bloqueio femoral contĂ­nuo foi guiado por ultrassom e estimulador de nervo para analgesia (grupo BFC); em 24 pacientes, analgesia foi administrada por via epidural (grupo ACP). Os efeitos analgĂ©sicos, efeitos colaterais, a recuperação articular e as complicaçÔes foram comparados entre os dois grupos.ResultadosÀs seis e 12 horas apĂłs a cirurgia, os escores de dor no joelho (escore EVA) durante os testes funcionais apĂłs exercĂ­cio ativo e passivo foram significativamente menores no grupo BFC do que no grupo ACP. A quantidade usada de parecoxib nos pacientes do grupo BFC foi significativamente menor em comparação com o grupo ACP. Quarenta e oito horas apĂłs a cirurgia, o grau de força muscular no grupo BFC foi significativamente maior e o tempo de atividade ambulatĂłria foi menor do que no grupo ACP. A incidĂȘncia de nĂĄusea e vĂŽmito em pacientes do grupo BFC foi significativamente menor em comparação com o grupo ACP.ConclusĂŁoO bloqueio femoral contĂ­nuo guiado por ultrassom e estimulador do nervo proporcionou melhor analgesia Ă s seis e 12 horas, demonstrada por EVA‐R e EVA‐P. A quantidade de parecoxib tambĂ©m foi menor, a incidĂȘncia de nĂĄusea e vĂŽmito diminuiu, a influĂȘncia sobre a força muscular Ă© comprometida e os pacientes podem fazer atividade ambulatorial sob essa condição.AbstractBackground and objectivesPostoperative analgesia is crucial for early functional excise after total knee arthroplasty. To investigate the clinical efficacy of ultrasound and nerve stimulator guided continuous femoral nerve block analgesia after total knee arthroplasty.Methods46 patients with ASA grade I–III who underwent total knee arthroplasty received postoperative analgesia from October 2012 to January 2013. In 22 patients, ultrasound and nerve stimulator guided continuous femoral nerve block were performed for analgesia (CFNB group); in 24 patients, epidural analgesia was done (PCEA group). The analgesic effects, side effects, articular recovery and complications were compared between two groups.ResultsAt 6h and 12h after surgery, the knee pain score (VAS score) during functional tests after active exercise and after passive excise in CFNB were significantly reduced when compared with PCEA group. The amount of parecoxib used in CFNB patients was significantly reduced when compared with PCEA group. At 48h after surgery, the muscle strength grade in CFNB group was significantly higher, and the time to ambulatory activity was shorter than those in PCEA group. The incidence of nausea and vomiting in CFNB patients was significantly reduced when compared with PCEA group.ConclusionUltrasound and nerve stimulator guided continuous femoral nerve block provide better analgesia at 6h and 12h, demonstrated by RVAS and PVAS. The amount of parecoxib also reduces, the incidence of nausea and vomiting decreased, the influence on muscle strength is compromised and patients can perform ambulatory activity under this condition
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