68 research outputs found

    Improvement of acid protease production by a mixed culture of Aspergillus niger and Aspergillus oryzae using solid-state fermentation technique

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    The synthesis of acid protease by Aspergillus oryzae AS3042 was enhanced significantly with the mixed culture of Aspergillus niger SL-09 using solid-state fermentation technique. The influence of carbon sources, nitrogen sources and the addition of phytic acid on acid protease production were investigated. The enzyme production varied depending on the nitrogen source. Apart from that, it was found that the enzyme activities formed in the mixed culture were enhanced dramatically by the addition of phytic acid to the medium. The response surface methodology (RSM) was used to optimize the medium composition for the production of acid protease and by this method the enzyme activity was enhanced near 5-fold higher than that obtained in the basal medium.Key words: Acid protease, Aspergillus niger, Aspergillus oryzae, solid-state culture, optimization, response surface methodology (RSM)

    An optimum medium designed and verified for alcohol vinegar fermentation

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    In this article, a novel formula of nutrient salt for alcohol vinegar production was derived based on mass conservation theory of carbon source, nitrogen source and inorganic ions. Series of semicontinuous fermentations were successfully carried out in a Frings 10 L fermentation tank. The average acetification rate of semi-continuous fermentation was 2 g acetic acid/L*h within about 12 h, average stoichiometric yield was 94%, and then fed-batch trial for high concentration vinegar fermentation was successfully conducted. Both of these confirmed that this method applied was cost-effective. If this method is adopted in industry scale, vinegar manufacturers will reduce production cost significantly.Key words: Formula, alcohol vinegar, fermentation nutrient

    PLK1 facilitates chromosome biorientation by suppressing centromere disintegration driven by BLM-mediated unwinding and spindle pulling

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    Centromeres provide a pivotal function for faithful chromosome segregation. They serve as a foundation for the assembly of the kinetochore complex and spindle connection, which is essential for chromosome biorientation. Cells lacking Polo-like kinase 1 (PLK1) activity suffer severe chromosome alignment defects, which is believed primarily due to unstable kinetochore-microtubule attachment. Here, we reveal a previously undescribed mechanism named ‘centromere disintegration’ that drives chromosome misalignment in PLK1-inactivated cells. We find that PLK1 inhibition does not necessarily compromise metaphase establishment, but instead its maintenance. We demonstrate that this is caused by unlawful unwinding of DNA by BLM helicase at a specific centromere domain underneath kinetochores. Under bipolar spindle pulling, the distorted centromeres are promptly decompacted into DNA threadlike molecules, leading to centromere rupture and whole-chromosome arm splitting. Consequently, chromosome alignment collapses. Our study unveils an unexpected role of PLK1 as a chromosome guardian to maintain centromere integrity for chromosome biorientation

    Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids

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    To progress from the laboratory to commercial applications, it will be necessary to develop industrially scalable methods to produce large quantities of defect-free graphene. Here we show that high-shear mixing of graphite in suitable stabilizing liquids results in large-scale exfoliation to give dispersions of graphene nanosheets. X-ray photoelectron spectroscopy and Raman spectroscopy show the exfoliated flakes to be unoxidized and free of basal-plane defects. We have developed a simple model that shows exfoliation to occur once the local shear rate exceeds 10(4) s(-1). By fully characterizing the scaling behaviour of the graphene production rate, we show that exfoliation can be achieved in liquid volumes from hundreds of millilitres up to hundreds of litres and beyond. The graphene produced by this method performs well in applications from composites to conductive coatings. This method can be applied to exfoliate BN, MoS2 and a range of other layered crystals

    c-Met activation leads to the establishment of a TGFβ-receptor regulatory network in bladder cancer progression

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    Treatment of muscle-invasive bladder cancer remains a major clinical challenge. Aberrant HGF/c-MET upregulation and activation is frequently observed in bladder cancer correlating with cancer progression and invasion. However, the mechanisms underlying HGF/c-MET-mediated invasion in bladder cancer remains unknown. As part of a negative feedback loop SMAD7 binds to SMURF2 targeting the TGFβ receptor for degradation. Under these conditions, SMAD7 acts as a SMURF2 agonist by disrupting the intramolecular interactions within SMURF2. We demonstrate that HGF stimulates TGFβ signalling through c-SRC-mediated phosphorylation of SMURF2 resulting in loss of SMAD7 binding and enhanced SMURF2 C2-HECT interaction, inhibiting SMURF2 and enhancing TGFβ receptor stabilisation. This upregulation of the TGFβ pathway by HGF leads to TGFβ-mediated EMT and invasion. In vivo we show that TGFβ receptor inhibition prevents bladder cancer invasion. Furthermore, we make a rationale for the use of combinatorial TGFβ and MEK inhibitors for treatment of high-grade non-muscle-invasive bladder cancers

    Ruthenium oxide-carbon-based nanofiller-reinforced conducting polymer nanocomposites and their supercapacitor applications.

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    In this review article, we have presented for the first time the new applications of supercapacitor technologies and working principles of the family of RuO2-carbon-based nanofiller-reinforced conducting polymer nanocomposites. Our review focuses on pseudocapacitors and symmetric and asymmetric supercapacitors. Over the last years, the supercapacitors as a new technology in energy storage systems have attracted more and more attention. They have some unique characteristics such as fast charge/discharge capability, high energy and power densities, and long stability. However, the need for economic, compatible, and easy synthesis materials for supercapacitors have led to the development of RuO2-carbon-based nanofiller-reinforced conducting polymer nanocomposites with RuO2. Therefore, the aim of this manuscript was to review RuO2-carbon-based nanofiller-reinforced conducting polymer nanocomposites with RuO2 over the last 17 years

    Measures of frailty in population-based studies: An overview

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    Although research productivity in the field of frailty has risen exponentially in recent years, there remains a lack of consensus regarding the measurement of this syndrome. This overview offers three services: first, we provide a comprehensive catalogue of current frailty measures; second, we evaluate their reliability and validity; third, we report on their popularity of use

    The Optimization of Mechanical and Electrical Integration Linear Output Transmission System with Sensor Function

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    The new highly integrated mechanical and electrical integration linear output sensor system designed is used to solve the problems of movement conversion/transmission, force transmission/ measurement etc. Firstly, further theory study is presented and the function of sensing parameters and transmission parameters is deduced; Secondly, the key parameters of system design and the constrained conditions are shown based on the system structure and strength theory. At last through simulation to determine the optimal structure parameters meeting the specific conditions and establish the corresponding relationship of parameters for future design
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