1,470 research outputs found

    Hopf-cyclic cohomology of the Connes-Moscovici Hopf algebras with infinite dimensional coefficients

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    We discuss a new strategy for the computation of the Hopf-cyclic cohomology of the Connes-Moscovici Hopf algebra Hn\mathcal{H}_n. More precisely, we introduce a multiplicative structure on the Hopf-cyclic complex of Hn\mathcal{H}_n, and we show that the van Est type characteristic homomorphism from the Hopf-cyclic complex of Hn\mathcal{H}_n to the Gelfand-Fuks cohomology of the Lie algebra WnW_n of formal vector fields on Rn\mathbb{R}^n respects this multiplicative structure. We then illustrate the machinery for n=1n=1.Comment: Minor revisions to highlight the main result

    Preliminary assessment of various additives on the specific reactivity of anti- rHBsAg monoclonal antibodies

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    Background: Antibodies have a wide application in diagnosis and treatment. In order to maintain optimal stability of various functional parts of antibodies such as antigen binding sites, several approaches have been suggested. Using additives such as polysaccharides and polyols is one of the main methods in protecting antibodies against aggregation or degradation in the formulation. The aim of this study was to evaluate the protective effect of various additives on the specific reactivity of monoclonal antibodies (mAbs) against recombinant HBsAg (rHBsAg) epitopes. Methods: To estimate the protective effect of different additives on the stability of antibody against conformational epitopes (S3 antibody) and linear epitopes (S7 and S11 antibodies) of rHBsAg, heat shock at 37°C was performed in liquid and solid phases. Environmental factors were considered to be constant. The specific reactivity of antibodies was evaluated using ELISA method. The data were analyzed using SPSS software by Mann-Whitney nonparametric test with the confidence interval of 95%. Results: Our results showed that 0.25 M sucrose, 0.04 M trehalose and 0.5% BSA had the most protective effect on maintaining the reactivity of mAbs (S3) against conformational epitopes of rHBsAg. Results obtained from S7 and S11 mAbs against linear characteristics showed minor differences. The most efficient protective additives were 0.04 M trehalose and 1 M sucrose. Conclusion: Nowadays, application of appropriate additives is important for increasing the stability of antibodies. It was concluded that sucrose, trehalose and BSA have considerable effects on the specific reactivity of anti rHBsAg mAbs during long storage. © 2015, Avicenna Journal of Medical Biotechnology. All rights reserved

    Expression of an innate immune element (mouse hepcidin-1) in baculovirus expression system and the comparison of its function with synthetic human hepcidin-25

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    Hepcidin is an innate immune element which decreases the iron absorption from diet and iron releasing from macrophage cell. In contrast to the chemical iron chelators, there has been limited effort applied to the specific use of hepcidin as a new drug for decreasing the iron overload. Hepcidin is produced in different biological systems. For instance, E-coli is used for human hepcidin expression, however, post-translational modification is impaired. We have used a simple baculovirus expression system (BES) to improve the hepcidin folding and activity. Hepcidin Messenger Ribonucleic acid (mRNA) was isolated from mouse liver cells and its complementary Deoxyribonucleic acid (cDNA) was produced and amplified. PFastBac HTB vector was used for recombinant bacmid production. Recombinant baculovirus was produced using SF-9 cell line. The mouse hepcidin-1 protein was expressed in a large quantity and functional tests were performed for this recombinant peptide. The yield of hepcidin in BES was 20 μg/mL and anti-histidine (anti-His) tag antibody was used for the confirmation of hepcidin on western blot nitrocellulose paper. Functional tests showed that mouse hepcidin accumulates iron in the macrophage cell line J774A.1 up to 63%. In addition, our data showed that the mouse hepcidin-1 has less toxicity compared to the synthetic human hepcidin-25 (p = 0.000). © 2011 by School of Pharmacy

    Is the high cu tolerance of trichoderma atroviride isolated from the cu-polluted sediment due to adaptation?: an in vitro toxicological study

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    The tolerance of Cu by Trichoderma atroviride, a tolerant fungus isolated from the drainage surface sediment of the Serdang Industrial Area was investigated under in vitro conditions. Only this fungus species can tolerate up to 600 mg/L of Cu on solid medium Potato Dextrose Agar based on the isolation of the most tolerant fungus from the polluted sediment. Toxicity test performed on T. atroviride, showed a maximum tolerance at 300 mg/L of Cu concentration when grown in liquid medium Potato Dextrose Broth (PDB). The EC50 value of the isolate was 287.73 mg/L of Cu concentration in PDB. The Cu concentration in the drainage surface sediment, where the T. atroviride was isolated from, was 347.64 μg/g while the geochemical distributions of the non-resistant and resistant fractions of Cu were 99.6 and 0.4%, respectively. The sediment data indicated that the drainage had greatly received anthropogenic Cu from the nearby industries which are involved in the manufacturing of plastics and electronic products. The present findings indicate that the high Cu tolerance showed by T. atroviride could be due to the well adaptation of the fungus to the Cu polluted sediment. Therefore, T. atroviride could be a potential bioremediator of Cu pollution in the freshwater ecosystem

    Curiosity cloning: neural analysis of scientific knowledge

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    Event-related potentials (ERPs) are indicators of brain activity related to cognitive processes. They can be de- tected from EEG signals and thus constitute an attractive non-invasive option to study cognitive information pro- cessing. The P300 wave is probably the most celebrated example of an event-related potential and it is classically studied in connection to the odd-ball paradigm experi- mental protocol, able to consistently provoke the brain wave. We propose the use of P300 detection to identify the scientific interest in a large set of images and train a computer with machine learning algorithms using the subject’s responses to the stimuli as the training data set. As a first step, we here describe a number of experiments designed to relate the P300 brain wave to the cognitive processes related to placing a scientific judgment on a picture and to study the number of images per seconds that can be processed by such a system

    A novel diblock copolymer of (monomethoxy poly [ethylene glycol]-oleate) with a small hydrophobic fraction to make stable micelles/polymersomes for curcumin delivery to cancer cells

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    Curcumin is a potent natural anticancer agent, but its effectiveness is limited by properties such as very low solubility, high rate of degradation, and low rate of absorption of its hydrophobic molecules in vivo. To date, various nanocarriers have been used to improve the bioavailability of this hydrophobic biomaterial. This study investigates the encapsulation of curcumin in a novel nanostructure of monomethoxy poly(ethylene glycol)-oleate (mPEG-OA) and its anticancer effect. Tests were done to determine the critical micelle concentration (CMC), encapsulation efficiency, drug-loading efficiency, and cytotoxicity (against U87MG brain carcinoma cells and HFSF-PI3 cells as normal human fibroblasts) of some nanodevice preparations. The results of fluorescence microscopy and cell-cycle analyses indicated that the in vitro bioavailability of the encapsulated curcumin was significantly greater than that of free curcumin. Cytotoxicity evaluations showed that half maximal inhibitory concentrations of free curcumin and curcumin-loaded mPEG-OA for the U87MG cancer cell line were 48 μM and 24 μM, respectively. The Annexin-V-FLUOS assay was used to quantify the apoptotic effect of the prepared nanostructures. Apoptosis induction was observed in a dose-dependent manner after curcumin-loaded mPEG-OA treatments. Two common self-assembling structures, micelles and polymersomes, were observed by atomic force microscopy and dynamic light scat­tering, and the abundance of each structure was dependent on the concentration of the diblock copolymer. The mPEG-OA micelles had a very low CMC (13.24 μM or 0.03 g/L). Moreover, atomic force microscopy and dynamic light scattering showed that the curcumin-loaded mPEG-OA polymersomes had very stable structures, and at concentrations 1,000 times less than the CMC, at which the micelles disappear, polymersomes were the dominant structures in the dispersion with a reduced size distribution below 150 nm. Overall, the results from these tests revealed that this nanocarrier can be considered as an appropriate drug delivery system for delivering curcumin to cancer cells. © 2014 Erfani-Moghadam et al

    Molecular cloning and expression of novel fibroblast growth factor-2 conjugated with immunodominant domains of pseudomonas exotoxin

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    Angiogenesis is very important in cancer growth and metastasis. Basic fibroblast growth factor (bFGF) as one of the most important angiogenesis factors is an attractive target for cancer vaccine. Due to low immunogenicity, it cannot stimulate an effective immune response. Theoretically, pseudomonas exotoxin (PE) as a potent immunogenic carrier protein when fused to low immunogenic antigens such as bFGF significantly increased immunogenicity of it. In this study, we tried to molecular cloning and expression of bFGF conjugated with immunodominant domains of pseudomonas exotoxin. The coding sequence of fusion protein composed of bFGF linked to PE domains 1b and 2 using EAAAK poly linker. The KDEL sequence was also used in C-terminal coding sequence. It was synthesized and expressed using recombinant DNA technology in the bacterial expression system. Expression of recombinant protein verified using SDS-PAGE and western blot analyses. Finally, it purified using Ni-affinity chromatography. The band close to 37 kDa in SDS-PAGE and western blot analyses was aligned completely to designed sequence. Purified recombinant protein also showed as a clear single band near to 37 kDa

    Exact microscopic analysis of a thermal Brownian motor

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    We study a genuine Brownian motor by hard disk molecular dynamics and calculate analytically its properties, including its drift speed and thermal conductivity, from microscopic theory.Comment: 4 pages, 5 figure

    Observation of the parallel-magnetic-field-induced superconductor-insulator transition in thin amorphous InO films

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    We study the response of a thin superconducting amorphous InO film with variable oxygen content to a parallel magnetic field. A field-induced superconductor-insulator transition (SIT) is observed that is very similar to the one in normal magnetic fields. As the boson-vortex duality, which is the key-stone of the theory of the field-induced SIT, is obviously absent in the parallel configuration, we have to draw conclusion about the theory insufficiency.Comment: 3 pages, 4 figure
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