1,055 research outputs found

    Some Weyl modules of the algebraic groups of type E6E_6

    Full text link
    Let GG be a simple algebraic group of type E6E_6 over an algebraically closed field of characteristic p>0p>0. We determine the submodule structure of the Weyl modul es with highest weight rω1r\omega_1 for 0rp10\leq r\leq p-1, where ω1\omega_1 is the fundamental weight of the standard 2727-dimensional module. In the process, the structures of other Weyl modules with highest weights linked to rω1r\omega_1 are also found. %We also give some computations for the Weyl modules with highest weights %of the form r(ω1+ω6)r(\omega_1+\omega_6), which arise in the study of %the graph automorphism and associated twisted finite groups.Comment: 25 page

    Periplasmic Expression, Recovery and Quantification of Recombinant Human Interferon-A2b in Fermentation by Escherichia Coli

    Get PDF
    Human interferon-α2b (IFN-α2b) is one of the biopharmaceuticals used to cure diseases such as hairy cell leukemia, malignant melanoma, and chronic hepatitis (B and C). Several areas related to the industrial problems, in the development of soluble IFN-α2b from recombinant Escherichia coli were explored in this study, which include enhancement of expression in periplasm, cell disruption techniques, quantification method and purification. The use of pET 26b(+) plasmid enhanced the periplasmic expression of IFN-α2b (300 ng/mL) by about 3000 times in E. coli RG 2(DE3) as compared to that obtained in the previous recombinant strain (0.1 ng /mL) using pFLAG-ATS plasmid. Difference in the expression level was attributed to the difference in the promoters and the signal sequences. In silico analysis suggested that the enhancement was mainly due to the difference in the translation initiation caused by mRNA secondary structure of the plasmid.The disruption of E. coli cells were investigated using glass bead shaking and homogenizer for small and large scale purpose, respectively. The optimum conditions for glass bead shaking were 30 min shaking at 300 rpm with 1.5 g/mL of glass beads (0.5 mm diameter). This technique was particularly useful for handling many samples at one time. The operating pressure range in a homogenizer was classified as low, transition and high pressures based on the characteristics of cell disintegrates. At low pressures, the protein release was mainly due to point break, which lead to high selectivity of IFN-α2b release. At higher pressures, the maximum release of total protein and IFN-α2b with a drastic reduction in cell size was observed after the first pass. Statistical optimization was used for osmotic shock process to release IFN-α2b at high concentration, with less process waste. Optimal process was achieved at cell concentration of 0.05 g/mL in hypertonic and 0.2 g/mL in hypotonic solutions. A rapid immunoassay method for quantification of IFN-α2b was developed using surface plasmon resonance technique. Anti-interferon monoclonal antibody (anti- IFN) was immobilized onto the CM5 chip using an amine coupling method. The perfect linearity was observed between 10 and 200 ng/mL. The anti-IFN chip was found to be useful for more than 1000 cycles and could also be used in continuous running environment. The efficacy of two activation methods using N-Hydroxysuccinimide in organic solvent (M I) and aqueous solution (M II) was assessed on CM Sepharose FF beads by immobilizing BSA onto it at various pH and ionic strengths. M I activation gave better immobilization efficiency than M II. Similar binding capacity was obtained with beads immobilized at pH 5 and 8 using anti-IFN; and with crude IFN-α2b as ligand and ligate. Knowledge gained from the molecular work gave better understanding of the expression pathway for future improvement of periplasmic IFN-α2b production by E. coli. Information and data obtained from this study were very useful for the development of efficient downstream and purification methods of IFN-α2b from E. coli fermentation at reduced cost, as well as simple and cheap quantification method for quality control and process monitoring

    Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm

    Get PDF
    Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms

    PLC-SCADA Based Automated Logistics Warehouse Management System

    Get PDF
    This paper is based upon use of PLCs(Programmable Logic Controllers)and SCADA(Supervisory Control and Data Acquisition)for the purpose of automatic material handling inside the warehouse and the logistics industries . Involvement of manpower has various disadvantages and so automating the process will curb all the demerits The implementation of this system would reduce the work done by humans to about 90% and thereby resulting in the increase in work/process speed

    An Investigation of Order Review/Release Policies and Dispatching Rules for Assembly Job Shops with Multi Objective Criteria

    Get PDF
    AbstractThis work deals with the significant aspects of a simulation based experimental study of two shop floor control polices: order review/release (ORR) and dispatching rules for scheduling an assembly job shop in which multi-objective criteria is considered. A simulation of model of an assembly job shop which consists of one assembly work station with two machines and seven machining work stations with two machines in each work station is developed. Six dispatching rules and four ORR mechanisms identified from the literature are incorporated in the simulation model. Grey relational analysis is used for ranking the dispatching rule-ORR combinations. The performance measures considered in this study are mean flow time, mean tardiness and machine utilization. Simulation experiments have been conducted in an environment with products consisting of single level assembly structure, two level assembly structure and three level assembly job structures. The results indicate that Job Due Date rule with Interval Release policy performs better in comparison with the other dispatching rule- ORR combinations investigated in this study

    Local Projections of Low-Momentum Potentials

    Full text link
    Nuclear interactions evolved via renormalization group methods to lower resolution become increasingly non-local (off-diagonal in coordinate space) as they are softened. This inhibits both the development of intuition about the interactions and their use with some methods for solving the quantum many-body problem. By applying "local projections", a softened interaction can be reduced to a local effective interaction plus a non-local residual interaction. At the two-body level, a local projection after similarity renormalization group (SRG) evolution manifests the elimination of short-range repulsive cores and the flow toward universal low-momentum interactions. The SRG residual interaction is found to be relatively weak at low energy, which motivates a perturbative treatment

    Molecular ruby: exploring the excited state landscape

    Get PDF
    The discovery of the highly NIR-luminescent molecular ruby [Cr(ddpd)2]3+ (ddpd = N,N′-dimethyl-N,N′-dipyridin-2-ylpyridine-2,6-diamine) has been a milestone in the development of earth-abundant luminophors and has led to important new impulses in the field of spin-flip emitters. Its favourable optical properties such as a high photoluminescence quantum yield and long excited state lifetime are traced back to a remarkable excited state landscape which has been investigated in great detail. This article summarises the results of these studies with the aim to create a coherent picture of the excited state ordering and the ultrafast as well as long-timescale dynamics. Additional experimental data is provided to fill in gaps left by previous reports
    corecore