25,908 research outputs found
BioPartsDB: a synthetic biology workflow web-application for education and research
Synthetic biology has become a widely used technology, and expanding applications in research, education and industry require progress tracking for team-based DNA synthesis projects. Although some vendors are beginning to supply multi-kilobase sequence-verified constructs, synthesis workflows starting with short oligos remain important for cost savings and pedagogical benefit. We developed BioPartsDB as an open source, extendable workflow management system for synthetic biology projects with entry points for oligos and larger DNA constructs and ending with sequence-verified clones
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Kinetic studies of CO<inf>2</inf> methanation over a Ni/γ-Al<inf>2</inf>O<inf>3</inf> catalyst using a batch reactor
The methanation of CO₂ was investigated over a wide range of partial pressures of products and reactants using a gradientless, spinning-basket reactor operated in batch mode. The rate and selectivity of CO₂ methanation, using a 12 wt% Ni/γ-Al₂O₃ catalyst, were explored at temperatures 453 – 483 K and pressures up to 20 bar. The rate was found to increase with increasing partial pressures of H₂ and CO₂ when the partial pressures of these reactants were low; however, the rate of reaction was found to be insensitive to changes in the partial pressures of H₂ and CO₂ when their partial pressures were high. A convenient method of determining the effect of H₂O on the rate of reaction was also developed using the batch reactor and the inhibitory effect of H₂O on CO₂ methanation was quantified. The kinetic measurements were compared with a mathematical model of the reactor, in which different kinetic expressions were explored. The kinetics of the reaction were found to be consistent with a mechanism in which adsorbed CO₂ dissociated to adsorbed CO and O on the surface of the catalyst with the rate-limiting step being the subsequent dissociation of adsorbed CO.JYL was funded by the Cambridge International Scholarship Scheme. The Cambridge Philosophical Society, the Lundgren Research Award and Corpus Christi College are also gratefully thanked for contributing to the support of his PhD studies.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ces.2015.10.02
Dimerization-Induced Fermi-Surface Reconstruction in IrTe2
We report a de Haas-van Alphen (dHvA) oscillation study on IrTe2 single crystals showing complex dimer formations. By comparing the angle dependence of dHvA oscillations with band structure calculations, we show distinct Fermi surface reconstruction induced by a 1/5-type and a 1/8-type dimerizations. This verifies that an intriguing quasi-two-dimensional conducting plane across the layers is induced by dimerization in both cases. A phase transition to the 1/8 phase with higher dimer density reveals that local instabilities associated with intra-and interdimer couplings are the main driving force for complex dimer formations in IrTe2.X11149sciescopu
Characterization of upstream sequences from the 8S globulin gene of Vigna radiata
Seeds rich in protein in nature, are ideal bioreactors for economic production and storage of valueadded recombinant proteins and enzymes for industries. The upstream region of the seed storage protein gene is able to provide an attractive promoter for seed-specific expression of heterologous genes. Our previous research showed that 8S globulin occupied the majority of total soluble protein stored in seeds of mung bean (Vigna radiata), a rich source of protein, indicating that the promoter of this gene could be a seed-specific promoter with high activity. To improve the expression of heterologous proteins in plants to act as a bioreactor, the putative seed-specific promoter of 8S globulin gene was characterized in this study. Hence, this potential promoter of beta subunit gene of 8S globulin (8SGb) was isolated by genome walking. Analysis with various promoter prediction softwares showed that the promoter sequence possessed many common motifs related to gene transcription in the seed (such as W-box, ABRE element, E-box, etc.). The putative promoter was subsequently cloned into the binary vector pBI121-GFP by replacing the CaMV 35S promoter. The resultant construct designated as pBI-8SGb-GFP was transformed to mung bean cotyledon mesophyll protoplasts. Reporter gene GFP was expressed high in cotyledon protoplasts, which was detected by confocal microscopy, demonstrating the specific activity of 8SGb promoter in driving gene expression. This study also proved that the 8SGb promoter is an efficient regulatory element for plant seeds to act as a bioreactor.Key words: Seed-specific, promoter, genome walking, Vigna radiata
Decision support for personalized cloud service selection through multi-attribute trustworthiness evaluation
Facing a customer market with rising demands for cloud service dependability and security, trustworthiness evaluation techniques are becoming essential to cloud service selection. But these methods are out of the reach to most customers as they require considerable expertise. Additionally, since the cloud service evaluation is often a costly and time-consuming process, it is not practical to measure trustworthy attributes of all candidates for each customer. Many existing models cannot easily deal with cloud services which have very few historical records. In this paper, we propose a novel service selection approach in which the missing value prediction and the multi-attribute trustworthiness evaluation are commonly taken into account. By simply collecting limited historical records, the current approach is able to support the personalized trustworthy service selection. The experimental results also show that our approach performs much better than other competing ones with respect to the customer preference and expectation in trustworthiness assessment. © 2014 Ding et al
Sample entropy analysis of EEG signals via artificial neural networks to model patients' consciousness level based on anesthesiologists experience.
Electroencephalogram (EEG) signals, as it can express the human brain's activities and reflect awareness, have been widely used in many research and medical equipment to build a noninvasive monitoring index to the depth of anesthesia (DOA). Bispectral (BIS) index monitor is one of the famous and important indicators for anesthesiologists primarily using EEG signals when assessing the DOA. In this study, an attempt is made to build a new indicator using EEG signals to provide a more valuable reference to the DOA for clinical researchers. The EEG signals are collected from patients under anesthetic surgery which are filtered using multivariate empirical mode decomposition (MEMD) method and analyzed using sample entropy (SampEn) analysis. The calculated signals from SampEn are utilized to train an artificial neural network (ANN) model through using expert assessment of consciousness level (EACL) which is assessed by experienced anesthesiologists as the target to train, validate, and test the ANN. The results that are achieved using the proposed system are compared to BIS index. The proposed system results show that it is not only having similar characteristic to BIS index but also more close to experienced anesthesiologists which illustrates the consciousness level and reflects the DOA successfully.This research is supported by the Center forDynamical Biomarkers and Translational Medicine, National Central University, Taiwan, which is sponsored by Ministry of Science and Technology (Grant no. MOST103-2911-I-008-001). Also, it is supported by National Chung-Shan Institute of Science & Technology in Taiwan (Grant nos. CSIST-095-V301 and CSIST-095-V302)
Ultrasonic Sizing of Voids Using Area Functions
We present a simple technique for determining the size of voids by the inversion of backscattered ultrasonic signals using the area function formula. The formulation of this method is based on the Born approximation, which is a weak scattering approximation, but the method works well for voids. The area function has been widely used as a method for determining the position of the flaw centroid to assist implementation of some inversion algorithms. The method has been reported in [6]. Here, we report some further studies, and more experimental results in detail
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Improving hydrogen yields, and hydrogen: Steam ratio in the chemical looping production of hydrogen using Ca<inf>2</inf>Fe<inf>2</inf>O<inf>5</inf>
A thermodynamic property of Ca2Fe2O5 was exploited to improve the efficiency of the steam-iron process to produce hydrogen. The ability of reduced Ca2Fe2O5 to convert a higher fraction of steam to hydrogen than chemically unmodified Fe was demonstrated in a packed bed. At 1123 K, the use of Ca2Fe2O5 achieved an equilibrium conversion of steam to hydrogen of 75%, in agreement with predicted thermodynamics and substantially higher than that theoretically achievable by iron oxide, viz. 62%. Furthermore, in Ca2Fe2O5, the full oxidation from Fe(0) to Fe(III) can be utilised for hydrogen production – an improvement from the Fe to Fe3O4 transition for unmodified iron. Thermodynamic considerations demonstrated in this study allow for the rational design of oxygen carriers in the future. Modifications of reactors to capitalise on this new material are discussed.Dr Matthew T. Dunstan is acknowledged for help with the XRD analysis. M.S.C.C acknowledges financial support from an EPSRC Doctoral Training Grant. W.L and Y.Y acknowledge funding from the National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.cej.2016.03.13
Influenza-associated hospitalisation.
The disease burden associated with influenza includes not only acute respiratory diseases but also cerebrovascular disease, ischaemic heart disease and diabetes mellitus.published_or_final_versio
Cell number quantification of USPIO-labeled stem cells by MRI: An in vitro study
MRI plays an expanding role in stem cell therapies. The non-invasive nature and high spatial resolution of MR imaging make MR imaging a powerful tool to investigate biologic processes at the molecular and cellular level in vivo longitudinally. Quantitative detection of stem cells after transplantation may allow assessment of stem cell localization and migration, and monitoring of the therapeutic effectiveness of stem cell therapy. In this study, we present a technique for MR quantification of magnetically labeled mouse embryonic stem cells distributed or injected in agarose gel phantoms. Apparent transverse relaxation rate enhancements (ΔR2*) were measured by gradient echo sequences. The linear relationship between ΔR2* and the concentration of USPIO-labeled mouse embryonic stem cells was observed and used for quantifying cell density and cell number after injection or transplantation. The MRI acquisition and analysis protocol were validated by good agreement between actual cell numbers and MRI-estimated cell numbers over a wide range of cell numbers. This MR technique for cell number and cell density quantification is applicable to future in vivo studies. © 2006 IEEE.published_or_final_versio
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