13 research outputs found
Antibody Epitope Specificity for dsDNA Phosphate Backbone Is an Intrinsic Property of the Heavy Chain Variable Germline Gene Segment Used
No full textAnalysis of protein sequences by the informational spectrum method (ISM) enables characterization of their specificity according to encoded information represented with defined frequency (F). Our previous data showed that F(0.367) is characteristic for variable heavy chain (VH) domains (a combination of variable (V), diversity (D) and joining (J) gene segments) of the anti-phosphocholine (PC) T15 antibodies and mostly dependent on the CDR2 region, a site for PC phosphate group binding. Because the T15 dsDNA-reactive U4 mutant also encodes F(0.367), we hypothesized that the same frequency may also be characteristic for anti-DNA antibodies. Data obtained from an analysis of 60 spontaneously produced anti-DNA antibody VH domain sequences supported our hypothesis only for antibodies, which use V gene segment in germline configuration, such as S57(VH31), MRL-DNA22, and VH11, members of the VH1 (J558) and VH7 (S107) gene families. The important finding is that out of seven V gene segments used by spontaneous anti-DNA antibodies, F(0.367) is only expressed by the germline configuration of these three V gene segments. The data suggest that antibody specificity for the phosphate group moiety delineated as F(0.367) is the intrinsic property of the V germline gene segments used, whereas paratope/epitope interaction with antigens bearing this epitope, such as PC or dsDNA, requires corresponding antibody VH conformation that is susceptible to somatic mutation(s). © 2018 Srdic-Rajic, Kohler, Jurisic and Metlas
Antibody VH domain sequence analysis by a bioinformatics approach based on electronic amino acid properties may help to predict paratop location
No full textGene as the basic functional unit of DNA encodes information about the product such as protein. The majority of proteins realize function through protein-protein interactions involving short protein motifs. However, some proteins such as antibodies are established by the rearrangement of several (V-D-J) gene segments with the potential addition of nontemplated nucleotides that may change information encoded by the respective gene segment used. Antibody VH domain sequence analysis by ISM bioinformatics approach that is based on amino acids physicochemical features, enable to distinguish the contribution of the information encoded by VH gene or generated during VDJ gene recombination for antibody-antigen interaction. The data presented in this report revealed the significance of CDRH3 for the interaction of antibody specific for immunogenic molecules while CDRH3 contribution is minor for antibody interaction with nonimmunogenic molecules such as haptens and native mammalian dsDNA. Thus, paratopes might be located in the CDRH3 or VH regions
(Table 2, page 62) Chemical composition of Mn nodules and crusts from the Pacific Ocean
No full textA complete processing method has been experimentally developed at laboratory scale for the future extraction of metlas from manganese nodules. The digestion of the nodules is performed by pressured sulfuric acid leaching at 200° C., nickel, copper, cobalt, and zinc being selectively dissolved in solution along with iron and manganese. The subsequent separation and recovery of the valuable metals is carried out with a combination of ion exchange and precipitation processes. Estimates for this methodology based on an annual throughput of 2 million tonnes of manganese nodules should lead to the production of about 24000 tonnes of nickel, 20000 tonnes of copper, and 3000 tonnes of cobalt and zinc. The authors conclude that, despite all uncertainty regarding the metal processing costs and the future metal prices, the exploitation of manganese nodules is economically viable
Human Immunodeficiency Virus V3 Peptide-Reactive Antibodies Are Present in Normal HIV-Negative Sera
No full textEstudo de diferentes rotas de processamento para refino de grão e seu efeito na estampabilidade de aços ARBL
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência e Engenharia de Materiais.As indústrias do setor metal-mecânico, principalmente as laminadoras, estão produzindo, atualmente, materiais por processamento termomecânico com grãos cada vez mais finos. Esta é uma forma de aumentar a resistência mecânica, a tenacidade e a soldabilidade. Devido a esta tendência e sabendo-se que o refino de grão de chapas metálicas está relacionado com aumento de resistência mecânica e com possível diminuição de estampabilidade das mesmas, os objetivos deste trabalho foram o desenvolvimento de novas rotas de processamentos termomecânicos (laminação a frio e tratamentos térmicos) e o estudo do efeito do tamanho de grãos nas propriedades mecânicas e na estampabilidade de aços microligados classificados, também, como aços ARBL (alta resistência baixa liga). O trabalho foi dividido em quatro etapas: i) caracterização dos materiais como fornecidos; ii) simulações de novas rotas de processamento em laboratório; iii) teste industrial com a rota simulada em laboratório que apresentou maior efeito no refino de grãos e iv) estudo da estampabilidade. A caracterização dos materiais envolveu ensaios metalográficos e levantamento das propriedades mecânicas de chapas de aços C-Mn e microligados (ao Nb e Nb-Ti) como produzidas industrialmente. Em seguida foram desenvolvidos novos caminhos para processamento em laboratório, visando, principalmente, o aumento de sítios de nucleação de novos grãos após deformação, com o intuito de refinar o grão ferrítico. As variáveis estudadas incluíram parâmetros de têmpera, revenido e recozimento. Após avaliação das simulações em laboratório, a rota com maior eficácia foi submetida à teste em escala industrial. Para este teste, apenas um aço foi processado, no caso o aço microligado ao Nb+Ti, por apresentar melhores resultados, quanto ao refino de grãos e aumento da resistência mecânica, e por ser o mais utilizado pela indústria fornecedora. Por fim, foi realizada a avaliação da estampabilidade com base nos resultados dos ensaios de tração, anisotropia, textura cristalográfica e curvas limite de conformação (CLC), de forma comparativa entre as tiras produzidas no teste industrial e as tiras do produto atualmente produzido pela indústria. Para o aço microligado ao Nb-Ti constatou-se um refino de grão de 15,3 µm de diâmetro inicial, em média, para 7,7 µm. Os resultados das propriedades mecânicas obtidas, do coeficiente de anisotropia normal e planar e a análise de textura pela função de distribuição de orientação cristalográfica, indicam uma estampabilidade inferior, uma menor possibilidade de formar "orelhas" no embutimento e uma menor anisotropia de propriedades das chapas obtidas pelo novo processamento. A mesma observação foi feita através do levantamento das CLC's para situações de embutimento, onde houve redução dos limites de deformação. Já em situações de estiramento, o limite de deformações apresentou pequeno aumento devido ao efeito da morfologia e homogeneidade de distribuição dos grãos. The industries of metal-mechanic sector are producing materials by thermomechanical processing, with grains smaller. This is a way to increase the mechanical strength, toughness and weldability. Based on these facts and knowing that the refining of grain is related to the mechanical strength and the formability, the objective of this research was the development of possible new routes involving thermomechanical processing (cold rolling and heat-treatment) and the study of the effect of grain size in the variation of mechanical properties and formability of HSLA (high strength low alloy) steels. The research was divided into four stages: i) characterization of materials, ii) simulations of new processing routes in the laboratory; iii) industrial test with the route simulated in the laboratory that showed greater effect on the grain refining and iv) study of formability. The characterization involved analysis of the microstructure and the mechanical properties of plates of C-Mn steels and microalloyed steels (Nb and Nb+Ti). After this stage, new ways for processing in the laboratory has been developed in order to generate areas of nucleation of new grains after deformation to refine the ferritic grain. Through evaluation of the simulations in the laboratory, the route with greater effectiveness was industrialy tested. In this case, only the best performing steel on the grain refinement and increased mechanical strength (Nb-Ti microalloyed steel) was processed. Finally the formability was evaluated by the results of tests of the strength, anisotropy, texture and forming limite diagrams (FLD), comparing the plates produced in the industrial test and the plates currently produced in industries. For Nb-Ti steel, was reduced the grain size by 15.3 µm to 7.7 µm. The results of the mechanical properties obtained, the coefficient of anisotropy and the texture analysis of the crystal orientation distribution function, indicate a lower formability, a smaller possibility to generate defects in inlay and a lower anisotropy of properties of the plates obtained by the new process. The same observation was obtained through FLD for inlaying situations, where there was reduction of the deformation limits. Already in stretching situations, the limit of deformations presented increase due to the effect of the morphology and homogeneity of distribution of the grains
Antibodies reactive with C-terminus of the second conserved region of HIV-1gp120 as possible prognostic marker and therapeutic agent for HIV disease
No full textIt has been reported that antibodies reactive with peptide RSANFTDNAKTIIVQLNQSVEIN (peptide NTM) derived from the C-terminus of the second conserved domain of HIV-1 envelope glycoprotein gp120 could represent an important factor in control of the HIV disease. In order to check this notion we (i) tested reactivity with peptide NTM serum samples collected from 310 consecutive HIV-1 infected patients with a CD4(+) lymphocyte count ranging from 10 to 800/muL and (ii) performed the longitudinal study that included 107 sera samples collected from 29 HIV patients. Results of these studies demonstrated correlation between presence of anti-NTM antibodies in sera of HIV patients and disease progression measured by the CD4(+) cell count. Based on these findings we proposed the anti-NTM antibodies as useful prognostic marker for HIV disease. (C) 2004 Elsevier B.V. All rights reserved
Effet des paramètres thermodynamiques et opératoires sur la granulation humide à fort taux de cisaillement
No full textCette étude est consacrée à la granulation humide en discontinu des poudres pharmaceutiques par pulvérisation des solutions liantes dans un granulateur à fort taux de cisaillement. Ce travail a pour objectif de développer des méthodologies prédictives et des outils d’investigation permettant de mieux choisir les paramètres thermodynamiques locaux afin d’assurer des propriétés d’usage bien définies des produits finaux. Nous avons donc étudié l’influence de deux paramètres thermodynamiques : énergie de surface et paramètre de solubilité de couple liant/solide. La caractérisation des énergies de surface de couple liant/substrat a été effectuée par la détermination de l’angle de contact. La détermination des paramètres de solubilité ou de cohésion a été effectuée en utilisant la simulation par dynamique moléculaire. La comparaison entre l’approche prédictive des paramètres de solubilité basée sur la simulation moléculaire et celle des énergies de surface a montré que les deux approches fournissent des informations qualitatives identiques concernant les intensités et les modes des interactions entre les solides. En se basant sur les interactions substrat/liant, l'hydroxypropylméthylcellulose est considérée comme le meilleur liant à employer pour la granulation des particules de cellulose microcristalline
Design of peptide mimetics of HIV-1 gp120 for prevention and therapy of HIV disease
No full textIt has been reported that the C-terminus of the second conserved region (C2) of the envelope glycoprotein gp120, encompassing peptide RSANFTDNAKTIIVQLNESVEIN (NTM), is important for infectivity and neutralization of the human immunodeficiency virus type 1 (HIV-1). It was also demonstrated that human natural anti-vasoactive intestinal peptide (VIP) antibodies reactive with this gp120 region play an important role in control of HIV disease progression. The bioinformatic analysis based on the time-frequency signal processing revealed non-obvious similarities between NTM and VIP. When tested against a battery of sera from 46 AIDS patients, these peptides, in spite of a significant difference in their primary structures, showed a similar reactivity profiles (r = 0.83). Presented results point out that similarity in the periodical pattern of some physicochemical properties in primary structures of peptides plays a significant role in determination of their immunological crossreactivity. Based on these findings, we propose this bioinformatic criterion be used for design of VIP/NTM peptide mimetics for prevention and treatment of HIV disease
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No full textEstudou-se a solidificação do aço rápido AISI M2, investigando-se os efeitos do teor de carbono (0,75; 0,95 e 1,15%), do teor de vanádio (1,0; 1,5; 2,0; 2,5%), de adições de nitrogênio (0,05%), antimônio (0,20 e 0,40%) e metais de terras raras (0,05 e 0,10%), bem como da velocidade de resfriamento (0,15; 1,5 e 15°Cs), sobre o espaçamento interdendrítico e a morfologia dos eutéticos \'M IND.2\'c, mc e \'M IND.6\'c. Utilizou-se a técnica de fusão sob cortina de argônio em forno de indução ao ar para a manutenção do teor de residuais, como o oxigênio e o nitrogênio, em baixos níveis. A solidificação dos corpos-de-prova foi acompanhada por métodos de análise térmica convencional e diferencial. A análise das microestruturas foi efetuada com o auxílio de ataques metalográficos seletivos, microscopia ótica, metalografia quantitativa computadorizada e manual, microscopias eletrônicas de varredura e de transmissão e microanálise por micro-sonda. Observou-se a diminuição do espaçamento interdendrítico com os aumentos do teor de carbono e da velocidade de resfriamento, bem como com as adições de N, Sb e metais de terras raras. A variação do teor de vanádio não exerceu influência sobre o espaçamento interdendrítico. Aquelas adições promoveram, ainda, uma distribuição mais homogênea das poças eutéticas na microestrutura e uma maior uniformidade do tamanho das mesmas.The effects of the carbon and vanadium contents ando f the cooling rate, as well as of nitrogem, antimonium and rre earth metlas (REM) additions on the dendrite arm spacing ando n the morphology of the M2C, MC and M6C eutectics were investigated. The heats were carried out in a high-frequency induction furnace with a continuous flow of argon over the melt surface in order to control the oxygen and nitrogen contents in a low level. The solidification of the samples was monitored by conventional and differential thermal analysis. The characterization of the microstructure was performed through selective etching, optical microscopy, quantitative metallography, SEM, TEM and microprobe analysis. Dendrite arm spacing decrease were promoted by increasing carbon content and cooling rate, and by additions of N, Sb and REM. The vanadium content had no influence on dendrite arm spacing. In addition, the eutectic pools of the N, Sb and REM-containing samples were more homogeneously distributed along the microstructure and presented less size variations. There was a competition between M2C and M6C eutectics formation. M2C eutectic was favored by high V content or high cooling rate, as well as by the presence of N and Sb. M6C eutectic was favored by low V contento r low cooling rate, as well as by the presence of REM. This competition was attributed to the metastability of the M2C eutectic. The morphology of the M6C eutectic was always complex-regular. Two types of M2C eutectic morphology were noticed: irregular, favored by high vanadium contento r low cooling rate, and complex-regular, favored by low vanadium contento r high cooling rate, as well as by the additions of N, Sb and REM. MC eutectic presented three types of morphology: divorced, irregular and complex regular. The formation of each type was determined by thedifference between MC eutectic temperature and peritectic temperature (the smaller this difference, the higher the cooperation degree of the eutectic phases). Antimonium and REM additions promoted the formation of a MC/M2C duplex eutectic which showed connected MC and M2C carbides. In the solidifications under 0,15°C/s, REM additions promoted the formation of a MC/M6C Duplex eutectic. The formation of these duplex eutectics was attributed to the decrease of the MC eutectic temperature
