601 research outputs found

    An ESPC algorithm based approach to solve inventory deployment problem

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    Global competitiveness has enforced the hefty industries to become more customized. To compete in the market they are targeting the customers who want exotic products, and faster and reliable deliveries. Industries are exploring the option of satisfying a portion of their demand by converting strategically placed products, this helps in increasing the variability of product produced by them in short lead time. In this paper, authors have proposed a new hybrid evolutionary algorithm named Endosymbiotic-Psychoclonal (ESPC) algorithm to determine the amount and type of product to stock as a semi product in inventory. In the proposed work the ability of previously proposed Psychoclonal algorithm to exploit the search space has been increased by making antibodies and antigen more cooperative interacting species. The efficacy of the proposed algorithm has been tested on randomly generated datasets and the results obtained, are compared with other evolutionary algorithms such as Genetic Algorithm (GA) and Simulated Annealing (SA). The comparison of ESPC with GA and SA proves the superiority of the proposed algorithm both in terms of quality of the solution obtained, and convergence time required to reach the optimal /near optimal value of the solution

    QuickStep-Cloning: a sequence-independent, ligation-free method for rapid construction of recombinant plasmids

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    Background Molecular cloning is an essential step in biological engineering. Methods involving megaprimer-based PCR of a whole plasmid are promising alternatives to the traditional restriction-ligation-based molecular cloning. Their widespread use, however, is hampered by some of their inherent characteristics, e.g., linear amplification, use of self-annealing megaprimers and difficulty with performing point insertion of DNA. These limitations result in low product yield and reduced flexibility in the design of a genetic construct. Result Here, we present a novel technique of directional cloning, which overcomes these problems yet retaining the simplicity of whole-plasmid amplification. QuickStep-Cloning utilizes asymmetric PCRs to create a megaprimer pair with 3â€Č-overhangs, and hence, facilitates the subsequent exponential whole-plasmid amplification. QuickStep-Cloning generates nicked-circular plasmids, thereby permitting direct bacterial transformation without DNA ligation. It allows DNA fragment integration into any plasmid at any position, in an efficient, time- and cost-effective manner, without tedious intermediate DNA gel purification, modified oligonucleotides, specialty enzymes and ultra-competent cells. The method is compatible with competent E. coli cells prepared using the conventional calcium chloride method. Conclusion QuickStep-Cloning expands the versatility of megaprimer-based cloning. It is an excellent addition to the cloning toolbox, for the benefit of protein engineers, metabolic engineers and synthetic biologists

    Design and application of genetically-encoded malonyl-CoA biosensors for metabolic engineering of microbial cell factories

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    Malonyl-CoA is the basic building block for synthesizing a range of important compounds including fatty acids, phenylpropanoids, flavonoids and non-ribosomal polyketides. Centering around malonyl-CoA, we summarized here the various metabolic engineering strategies employed recently to regulate and control malonyl-CoA metabolism and improve cellular productivity. Effective metabolic engineering of microorganisms requires the introduction of heterologous pathways and dynamically rerouting metabolic flux towards products of interest. Transcriptional factor-based biosensors translate an internal cellular signal to a transcriptional output and drive the expression of the designed genetic/biomolecular circuits to compensate the activity loss of the engineered biosystem. Recent development of genetically-encoded malonyl-CoA sensor has stood out as a classical example to dynamically reprogram cell metabolism for various biotechnological applications. Here, we reviewed the design principles of constructing a transcriptional factor-based malonyl-CoA sensor with superior detection limit, high sensitivity and broad dynamic range. We discussed various synthetic biology strategies to remove pathway bottleneck and how genetically-encoded metabolite sensor could be deployed to improve pathway efficiency. Particularly, we emphasized that integration of malonyl-CoA sensing capability with biocatalytic function would be critical to engineer efficient microbial cell factory. Biosensors have also advanced beyond its classical function of a sensor actuator for in situ monitoring of intracellular metabolite concentration. Applications of malonyl-CoA biosensors as a sensor-invertor for negative feedback regulation of metabolic flux, a metabolic switch for oscillatory balancing of malonyl-CoA sink pathway and source pathway and a screening tool for engineering more efficient biocatalyst are also presented in this review. We envision the genetically-encoded malonyl-CoA sensor will be an indispensable tool to optimize cell metabolism and cost-competitively manufacture malonyl-CoA-derived compounds

    Multizone decomposition for simulation of time-dependent problems using the multiquadric scheme

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    AbstractThis paper discusses the application of the multizone decomposition technique with multiquadric scheme for the numerical solutions of a time-dependent problem. The construction of the multizone algorithm is based on a domain decomposition technique to subdivide the global region into a number of finite subdomains. The reduction of ill-conditioning and the improvement of the computational efficiency can be achieved with a smaller resulting matrix on each subdomain. The proposed scheme is applied to a hypothetical linear two-dimensional hydrodynamic model as well as a real-life nonlinear two-dimensional hydrodynamic model in the Tolo Harbour of Hong Kong to simulate the water flow circulation patterns. To illustrate the computational efficiency and accuracy of the technique, the numerical results are compared with those solutions obtained from the same problem using a single domain multiquadric scheme. The computational efficiency of the multizone technique is improved substantially with faster convergence without significant degradation in accuracy

    Direct medical costs in the preceding, event and subsequent years of first severe hypoglycaemia requiring hospital transfer: A population-based cohort study

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    Aims To estimate healthcare services use and the direct medical costs accrued by patients with diabetes mellitus (DM) in the year of first severe hypoglycaemia (SH), the years before and after event year. Materials and Methods We analyzed a population‐based, retrospective cohort including all DM adults managed in primary care setting from the Hong Kong Hospital Authority between 2006‐2013. DM patients who had first recorded SH during the observation period were identified, and matched to control group of patients without SH based on the propensity score method. Direct medical costs in the years before, during and after the first SH were determined by summing up the costs of health services utilized within respective year. Results After matching, a total of 22,694 DM patients was identified in first recorded SH group (n=11,347) and non‐SH control group (n=11,347). Patients with first SH on average utilized 7.85 outpatient clinic visits, 1.89 emergency visits and 17.75 nights of hospitalization in the event year. Mean direct medical cost in the event year was US11,751,morethantwofoldofthatintheprecedingyear(US11,751, more than twofold of that in the preceding year (US4,846, p<0.001) and subsequent years (US4,198‐4,700,p<0.001),and4.5timesofthatintwoyearsbeforetheevent(US4,198‐4,700, p<0.001), and 4.5 times of that in two years before the event (US2,481, p<0.001). Incremental costs of SH versus matched control in the event year and preceding year were US10,873(p<0.001)andUS10,873 (p<0.001) and US3,974 (p<0.001), respectively. Conclusions SH is associated with excessive hospitalization admission rates and direct medical costs in the event year and, in particular, in the year before as compared to patients without SH

    Adaptive laboratory evolution of cupriavidus necator H16 for carbon co-utilization with glycerol

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    Cupriavidus necator H16 is a non-pathogenic Gram-negative betaproteobacterium that can utilize a broad range of renewable heterotrophic resources to produce chemicals ranging from polyhydroxybutyrate (biopolymer) to alcohols, alkanes, and alkenes. However, C. necator H16 utilizes carbon sources to different efficiency, for example its growth in glycerol is 11.4 times slower than a favorable substrate like gluconate. This work used adaptive laboratory evolution to enhance the glycerol assimilation in C. necator H16 and identified a variant (v6C6) that can co-utilize gluconate and glycerol. The v6C6 variant has a specific growth rate in glycerol 9.5 times faster than the wild-type strain and grows faster in mixed gluconate–glycerol carbon sources compared to gluconate alone. It also accumulated more PHB when cultivated in glycerol medium compared to gluconate medium while the inverse is true for the wild-type strain. Through genome sequencing and expression studies, glycerol kinase was identified as the key enzyme for its improved glycerol utilization. The superior performance of v6C6 in assimilating pure glycerol was extended to crude glycerol (sweetwater) from an industrial fat splitting process. These results highlight the robustness of adaptive laboratory evolution for strain engineering and the versatility and potential of C. necator H16 for industrial waste glycerol valorization

    Antibacterial Effect of Green Synthesized Silver Nanoparticles using Cineraria maritima

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    Nanoparticles display entirely novel physicochemical characteristics for specific applications because of their exceptional size and shape. Owing to the present study, we reported biosynthesis, characterization and antibacterial properties of Cineraria maritima (Cm) assisted silver nanoparticles (Ag NPs). The surface plasmon vibration, crystalline structure, surface morphology, elemental composition, and possible functional molecules vibration of prepared Cm-Ag NPs were characterized by different instrumentation techniques. The spectrum of UV-Vis of Cm-Ag NPs showed maximum plasma intensity occurred around 425nm. XRD spectrum showed the face-centred cubic (FCC) nature of Cm-Ag NPs. The SEM image of the Cm-Ag NPs demonstrated a predominantly spherical shape with cluster formation of small particles to large particles with sizes ranging from 21.57 nm to 39.16 nm. EDS spectrum indicated the existence of Ag elements in Cm-Ag NPs. FTIR intense peaks of Cm-Ag NPs showed the different functional molecules such as phenol, alkene, aldehydes, and a carbonyl group. In addition, Cm-Ag NPs coated textile cotton fabric sample showed substantial anti-bacterial properties against a tested bacterial pathogen

    A Dynamical Model of Color Confinement

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    A dynamical model of confinement based on a transport theoretical description of the Friedberg-Lee model is extended to explicit color degrees of freedom. The string tension is reproduced by an adiabatic string formation from the nucleon ground state. Color isovector oscillation modes of a qqˉq\bar{q}-system are investigated for a wide range of relative qqˉq\bar{q}-momenta and the dynamical impact of color confinement on the quark motion is shown.Comment: 12 pages plus 5 figure

    The chemokine lymphotactin and its recombinant variants in oral cancer cell regulation

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    Background The expression of XCR1 receptor and its metamorphic ligand lymphotactin (hLtn) has been shown in cancers but their precise role in tumorigenesis is poorly understood including the significance of the physiologically existing hLtn monomeric (CC3) and dimeric (W55D) confirmations where the latter thought to function as the receptor antagonist. The aim of this study was to explore the functional role of bioengineered hLtn variants and the role of fibroblasts in XCR1/hLtn expression regulation in oral cancer cells (OCCL). Material and methods qRT‐PCR and flow cytometry were performed to evaluate mRNA and protein expression of XCR1 and hLtn. Recombinant hLtn variants (wild‐type, CC3 and W55D mutant) were designed, expressed, purified and evaluated using proliferation, adhesion and chemotaxis assays. XCR1 and hLtn expression regulation by fibroblasts was determined using indirect co‐culture. XCR1 and hLtn expression in primary and metastatic OSCC tissue was assessed using immunohistochemistry. Results hLtn caused a significant decrease in OCCL XCR1 surface protein expression. hLtn CC3 mutant was highly functional facilitating proliferation and migration. Conditioned media from primary cancer‐associated and senescent fibroblasts significantly upregulated XCR1 and hLtn mRNA expression in OCCL. Immunohistochemistry revealed higher XCR1 and hLtn expression in metastatic tumour deposits and surrounding stroma compared to primary OSCC tissue. Conclusions The development of hLtn biological mutants, regulation of XCR1 expression by its ligand hLtn and crosstalk with fibroblasts are novel findings suggesting an important role for the XCR1/hLtn axis within the OSCC tumour microenvironment. These discoveries build upon previous studies and suggest that the hLtn/XCR1 axis has a significant role in stromal crosstalk and OSCC progression

    An engineered constitutive promoter set with broad activity range for Cupriavidus necator H16

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    Well-characterized promoters with variable strength form the foundation of heterologous pathway optimization. It is also a key element that bolsters the success of microbial engineering and facilitates the development of biological tools like biosensors. In comparison to microbial hosts such as Escherichia coli and Saccharomyces cerevisiae, the promoter repertoire of Cupriavidus necator H16 is highly limited. This limited number of characterized promoters poses a significant challenge during the engineering of C. necator H16 for biomanufacturing and biotechnological applications. In this article, we first examined the architecture and genetic elements of the four most widely used constitutive promoters of C. necator H16 (i.e., PphaC1, PrrsC, Pj5, and Pg25) and established a narrow 6-fold difference in their promoter activities. Next, using these four promoters as starting points and applying a range of genetic modifications (including point mutation, length alteration, incorporation of regulatory genetic element, promoter hybridization, and configuration alteration), we created a library of 42 constitutive promoters, all of which are functional in C. necator H16. Although these promoters are also functional in E. coli, they show different promoter strength and hierarchical rank of promoter activity. Subsequently, the activity of each promoter was individually characterized, using l-arabinose-inducible PBAD promoter as a benchmark. This study has extended the range of constitutive promoter activities to 137-fold, with some promoter variants exceeding the l-arabinose-inducible range of PBAD promoter. Not only has the work enhanced our flexibility in engineering C. necator H16, it presented novel strategies in adjusting promoter activity in C. necator H16 and highlighted similarities and differences in transcriptional activity between this organism and E. coli
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