7,943 research outputs found
The Beta Generalized Exponential Distribution
We introduce the beta generalized exponential distribution that includes the
beta exponential and generalized exponential distributions as special cases. We
provide a comprehensive mathematical treatment of this distribution. We derive
the moment generating function and the th moment thus generalizing some
results in the literature. Expressions for the density, moment generating
function and th moment of the order statistics also are obtained. We discuss
estimation of the parameters by maximum likelihood and provide the information
matrix. We observe in one application to real data set that this model is quite
flexible and can be used quite effectively in analyzing positive data in place
of the beta exponential and generalized exponential distributions
Anti-Candida targets and cytotoxicity of casuarinin isolated from Plinia cauliflora leaves in a bioactivity-guided study
Peer reviewedPublisher PD
Strategies to improve productivity of CHO-S cells expressing an anti-TNFα monoclonal antibody with biosimilar potential
Tumor necrosis factor alpha (TNFα) is a proinflammatory cytokine that mediates the homeostasis of immune responses; its exacerbated production is associated with the pathogenesis of autoimmune and chronic inflammatory diseases. Anti-TNFα drugs have revolutionized the treatment of inflammatory conditions such as rheumatoid arthritis and Crohn’s disease. Currently, a worldwide race is on stage for the production of biosimilars moved by patent expiration of monoclonal antibodies (mAbs), such as anti-TNFα adalimumab. This project is based on the first development stage for an adalimumab biosimilar candidate with potential for national production through the generation of a productive and stable cell line and assessment of its functionality. The robotic system ClonePix was used for screening and isolation of colonies from transfected CHO-S stable pools plated in semisolid medium. Selected clones were expanded based on growth and productivity. Purified mAbs from different clones were tested for binding and functional activity. The binding affinity of the denominated adabut clones to TNFα and FcRs, tested by surface plasmon resonance, did not differ statistically when compared to reference adalimumab. One functional activity assay demonstrated the antibody neutralization capacity of the cytotoxicity induced by TNFα in L929 murine fibroblasts. A second assay confirmed adabut as an antagonist of the TNFα activity by the inhibition of the cell adhesion molecule expression in HUVEC cultures. The binding kinetics and functional analysis performed suggest a potential for further development of adabut as a biosimilar. The process of the cell line development for adabut generated data consisting of cell growth/viability, volumetric and specific productivity, antigen binding kinetics, functional assays and long-term stability, from which 3 clones were selected. One clone (123) was top ranked and 2 others (70 and 225) showed equivalent performance. To increase the basal productivity of clone 123, 0.6g/L, we run 3 fed-batch experiments to evaluate 6 basal media, 8 supplements and a temperature shift to 32 C on day 6 on some conditions. The experiments were conducted in 250 and 500mL-shaker flasks along 14 days or while cell viability was above 60%. The flasks were sampled daily for cell counting/viability by Vi-Cell XR cell counter and glucose monitoring. Samples were stored for additional metabolites and antibody concentration assessment. By testing 24 different fed-batch strategies we were able to increase up to 6 times the volumetric clone productivity, while maintaining product quality. No significant differences were observed between the mAbs purified from days 14, 16 or 17 fed-batch cultures and the reference commercial product by SDS-PAGE, SEC-HPLC, IEX-HPLC and IEF analyses
Transcriptome analysis of Taenia solium cysticerci using Open reading Frame ESTS (ORESTES)
<p>Abstract</p> <p>Background</p> <p>Human infection by the pork tapeworm <it>Taenia solium </it>affects more than 50 million people worldwide, particularly in underdeveloped and developing countries. Cysticercosis which arises from larval encystation can be life threatening and difficult to treat. Here, we investigate for the first time the transcriptome of the clinically relevant cysticerci larval form.</p> <p>Results</p> <p>Using Expressed Sequence Tags (ESTs) produced by the ORESTES method, a total of 1,520 high quality ESTs were generated from 20 ORESTES cDNA mini-libraries and its analysis revealed fragments of genes with promising applications including 51 ESTs matching antigens previously described in other species, as well as 113 sequences representing proteins with potential extracellular localization, with obvious applications for immune-diagnosis or vaccine development.</p> <p>Conclusion</p> <p>The set of sequences described here will contribute to deciphering the expression profile of this important parasite and will be informative for the genome assembly and annotation, as well as for studies of intra- and inter-specific sequence variability. Genes of interest for developing new diagnostic and therapeutic tools are described and discussed.</p
Modulation of the electronic properties of GaN films by surface acoustic waves
We report on the interaction between photogenerated electron-hole pairs and surface acoustic waves (SAW) in GaN films grown on sapphire substrates. The spatial separation of photogenerated carriers by the piezoelectric field of the SAW is evidenced by the quenching of the photoluminescence (PL) intensity. The quenching levels in GaN are significantly smaller than those measured in GaAs under similar conditions. The latter is attributed to the lower exciton ionization efficiency and carrier separation probabilities mediated by the piezoelectric effect. The PL spectra also evidence energy shifts and broadenings of the electronic transitions, which are attributed to the band gap modulation by the SAW strain [email protected]
Virgin and recycled polypropylene composites reinforced with sisal by-product
Foram estudadas as propriedades térmicas e mecânicas de compósitos de polipropileno, virgem e reciclado, reforçados com 30% em massa de fibras residuais de sisal, assim como o perfil de processamento e a morfologia da matriz polimérica. Para tanto, foram determinadas a resistência à tração, o módulo de Young, alongamento na ruptura, e energia de impacto. As amostras também foram caracterizadas por MEV, DMTA e TG. Para ambos os compósitos de polipropileno, virgem e reciclado, com a adição das fibras, o alongamento na ruptura mostrou uma queda significativa, enquanto que a resistência à tração não sofreu grandes variações. Houve um aumento significativo nos valores de tração na ruptura e de energia de impacto com a adição das fibras de sisal na matriz de polipropileno. As análises térmicas mostraram ligações secundárias, como as ligações polares, entre as fibras e a matriz, concordando com o comportamento mecânico dos compósitos. Constatou-se que a temperatura de transição vítrea não variou após a adição da fibra.The mechanical and thermal properties of virgin and recycled polypropylene composites reinforced with 30% by mass of residual sisal fibers were studied, in addition to an analysis of the extrusion process and morphology of the polymeric matrix. Tensile strength, Young's modulus, elongation at break, and impact energy were determined. The samples were also characterized by SEM, DMTA and TG analyses. Elongation at break of the composites presented a significant decrease, while the tensile strength was not affected significantly by addition of sisal fibers. A significant increase was observed in the tension of rupture and in the impact energy of the composite reinforced with sisal fiber. The thermal analyses indicated secondary interactions, such as polar interactions, between the fibers and the matrix, consistent with the mechanical behavior of the composites. The glass transition temperature has not changed after fiber addition.Universidade Federal de São Carlos - Departamento de Engenharia de MateriaisFinepCNP
Oriented immobilization of Pep19-2.5 on antifouling brushes suppresses the development of Staphylococcus aureus biofilms
Bacterial colonization of indwelling medical devices poses a danger to the patient and is a tremendous economic burden that costs billions of dollars to the healthcare system. Thus, it is essential to develop an effective mechanism that prevents the attachment of bacteria to the surface in combination with bactericidal strategies to kill them in direct contact. In this work, we combine the repellent/antifouling properties of polymer brushes with the antimicrobial activity of the synthetic peptide Pep19-2.5 and test its efficacy to inhibit Staphylococcus aureus biofilm formation. To tackle this, we utilized hierarchical polymer brushes, where the bottom block provides an effective barrier against adhesion while the top block provides functional groups for the immobilization of active molecules. Further, these polymer brushes were decorated with dibenzocyclooctine (DBCO)-functionalized Pep19-2.5 using strain-promoted alkyne-azide cycloaddition (SPAAC). This click chemistry proceeds very fast and does not require any catalyst, which is crucial for biomedical applications. The obtained coating was not only able to decrease the number of freely planktonic bacteria in the surrounding media (by 52.5%) but also inhibit the development of S. aureus biofilm by reducing the number of total, viable, and viable but non-culturable (VBNC) cells (up to 58%, 66%, and 70% respectively) and reduce the biovolume and thickness. Conversely, this coating does not exert any cytotoxic effect on Normal Human Dermal Fibroblasts (NHDF) cells. Thus, the combination of hierarchical polymer brushes with Pep19-2.5 is a promising approach to fight medical biofilms without affecting surrounding tissues
Diacutaneous fibrolysis versus passive stretching after articular immobilisation : muscle recovery and extracellular matrix remodelling
Introduction
Atrophy and muscle shortening due to articular immobilisation are common problems in musculoskeletal rehabilitation. Muscle stretching mechanical stimuli might be considered as the golden standard procedure to improve muscle flexibility in rehabilitation. Muscle stretching generates mechanotransduction, potentiating specific gene expression and promotes sarcomerogenesis and extracellular matrix remodelling on shortened and atrophied muscles.
Hypothesis
Diacutaneous fibrolysis, like stretching, uses an external force to stress connective and muscle tissues mechanically to treat muscle shortening; thus, it is widely used in clinical practice even if there is no evidence to support it. Considering this subject, we have hypothesised that diacutaneous fibrolysis can generate mechanotransduction, affecting muscle hypertrophy and extracellular matrix remodelling after immobilisation.
Evaluation of hypothesis
We have designed a laboratory experimental study with a sample of 50 rats. The sample was randomly divided into five groups: Control group (n = 10) with non–immobilised rats; 3–week immobilisation group (n = 10); 3–week immobilisation/3–week non–immobilisation group (n = 10);3–week immobilisation/3–week stretching group (n = 10); and 3–week immobilisation/3–week diacutaneous fibrolysis group (n = 10). All rats had their left tibiotarsal joint immobilised in maximum plantar flexion with the orthotics for 3 consecutive weeks. After the immobilisation period, the intervention groups received their respective intervention on their left triceps suralis for 3 weeks. Dependent variables of the study were sarcomere analysis, polymerase chain reaction, connective tissue density, collagen birefringence and matrix metalloproteinases. Statistical analysis was performed using analysis of variance and Duncan post hoc test was applied for differences between groups. For all calculations, a 5% (p < 0.05) significance level was established.
Conclusion
If the hypothesis is confirmed, the present study might provide evidence to support the use of this physical therapy resource widely used to treat muscle dysfunctions
Ácido giberélico no crescimento inicial de mudas de pessegueiro.
O emprego de certas práticas culturais são fundamentais para obtenção de mudas de qualidade, com reduzido período de formação. Realizou-se, este trabalho, em casa de vegetação, no Departamento de Fitotecnia da Universidade Federal de Viçosa, com o objetivo de avaliar o efeito de cinco concentrações de ácido giberélico (GA3) (0; 50; 100; 150 e 200 mg L-1), no crescimento inicial do pessegueiro. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições, considerando-se como unidade experimental, os quatro recipientes plásticos contendo uma planta cada. Foram realizadas três aplicações de GA3 (60, 80 e 100 dias de cultivo). Nas aplicações, a parte aérea foi molhada inteiramente, utilizando-se 20 ml de solução para cada planta. Aos 130 dias da semeadura, foram analisados: comprimento da parte aérea e da raiz; diâmetro do caule; número de brotações primárias; massa da matéria seca da parte aérea e da raiz. Concluiu-se que o ácido giberélico exerceu efeito sobre o crescimento de pessegueiro, recomendando-se a pulverização de 200 mg L-1. As pulverizações de GA3 não tiveram efeito sobre o diâmetro do caule do pessegueiro
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