Improved tribology and materials for a new generation of hip prostheses

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Structure and application of antifreeze proteins from Antarctic bacteria

Indexación: Web of Science; Scopus.Background: Antifreeze proteins (AFPs) production is a survival strategy of psychrophiles in ice. These proteins have potential in frozen food industry avoiding the damage in the structure of animal or vegetal foods. Moreover, there is not much information regarding the interaction of Antarctic bacterial AFPs with ice, and new determinations are needed to understand the behaviour of these proteins at the water/ice interface. Results: Different Antarctic places were screened for antifreeze activity and microorganisms were selected for the presence of thermal hysteresis in their crude extracts. Isolates GU1.7.1, GU3.1.1, and AFP5.1 showed higher thermal hysteresis and were characterized using a polyphasic approach. Studies using cucumber and zucchini samples showed cellular protection when samples were treated with partially purified AFPs or a commercial AFP as was determined using toluidine blue O and neutral red staining. Additionally, genome analysis of these isolates revealed the presence of genes that encode for putative AFPs. Deduced amino acids sequences from GU3.1.1 (gu3A and gu3B) and AFP5.1 (afp5A) showed high similarity to reported AFPs which crystal structures are solved, allowing then generating homology models. Modelled proteins showed a triangular prism form similar to β-helix AFPs with a linear distribution of threonine residues at one side of the prism that could correspond to the putative ice binding side. The statistically best models were used to build a protein-water system. Molecular dynamics simulations were then performed to compare the antifreezing behaviour of these AFPs at the ice/water interface. Docking and molecular dynamics simulations revealed that gu3B could have the most efficient antifreezing behavior, but gu3A could have a higher affinity for ice. Conclusions: AFPs from Antarctic microorganisms GU1.7.1, GU3.1.1 and AFP5.1 protect cellular structures of frozen food showing a potential for frozen food industry. Modeled proteins possess a β-helix structure, and molecular docking analysis revealed the AFP gu3B could be the most efficient AFPs in order to avoid the formation of ice crystals, even when gu3A has a higher affinity for ice. By determining the interaction of AFPs at the ice/water interface, it will be possible to understand the process of adaptation of psychrophilic bacteria to Antarctic ice.https://microbialcellfactories.biomedcentral.com/articles/10.1186/s12934-017-0737-

Design aspects of compliant, soft layer bearings for an experimental hip prosthesis

Currently, an artificial hip joint can be expected to last, on average, in excess of 15 years with failure due, in the majority of cases, to late aseptic loosening of the acetabular component. A realistic alternative to the problem of wear in conventional joints is the introduction of bearing surfaces that exhibit low wear and operate in the full fluid-film lubrication regime. Contact analyses and friction tests were performed on compliant layer joints (metal-on-polyurethane) and the design of a prototype ovine arthroplasty model was investigated. When optimized, these components have been shown to achieve full fluid-film lubrication

Latin American genome initiative, the creation of a network and web based resource to aid and nurture genome biology in developing countries

[No abstract available

Latin American genome initiative, the creation of a network and web based resource to aid and nurture genome biology in developing countries

[No abstract available

Can Interrogation of Tumour Characteristics Lead us to Safely Omit Adjuvant Radiotherapy in Patients with Early Breast Cancer?

Adjuvant radiotherapy after breast-conserving surgery has been an important component of the standard of care for early breast cancer. Improvements in breast cancer care have resulted in a substantial reduction in local relapse rates over recent decades. Although the proportional benefits of adjuvant radiotherapy are similar for different prognostic risk groups of patients, the absolute benefits depend on the risk of relapse and therefore vary considerably between prognostic groups. Radiotherapy is not without risk and for some patients at very low risk of relapse the risks of radiotherapy may outweigh the benefit, leading to potential overtreatment. Randomised controlled trial (RCT) evidence shows that omission of radiotherapy in low risk early breast cancer does not reduce overall survival or increase breast cancer mortality and local recurrences are salvageable. Despite this there has not been a change in practice regarding omission of radiotherapy. The reasons for this may include challenges in patient selection. Recent advances in immunohistochemistry and genomic profiling may improve risk stratification and the development of biomarkers to directed therapies. Several RCTs have quantified the benefit of radiotherapy in reducing local relapse. Where a treatment benefit is known but is considered to be so small not to be clinically relevant then alternatives to RCTs may be considered to answer the question of need. This is because we can assess risk against a fixed 'absolute' boundary rather than needing a randomised comparator. The prospective cohort study is an alternative to the RCT design to answer the question of need for radiotherapy. The feasibility of recruitment into biomarker-directed de-escalation studies will become apparent as more studies open. The challenge is to determine if we are able to accurately risk stratify patients and avoid unnecessary toxicity, thereby tailoring the need for adjuvant breast radiotherapy on an individual patient basis. (C) 2018 The Royal College of Radiologists. Published by Elsevier Ltd

Desempenho agronômico da cultura do girassol em diferentes condições edafoclimáticas do Sudeste paranaense

O objetivo do presente trabalho foi quantificar as faixas de rendimentos acessíveis em diferentes condições edafoclimáticas do Sudeste paranaense e hierarquizar os fatores relacionados à variabilidade dos rendimentos observados. Foram avaliadas 26 situações culturais em 13 estabelecimentos familiares, em 2007 e 2008. As variáveis de componente do rendimento e estado nutricional da cultura foram determinadas pela coleta de dados em campo, e as variáveis de estado hídrico foram estimadas com o uso de um modelo de simulação do balanço hídrico. Estas foram analisadas pela Análise de Componentes Principais, classificando-se, posteriormente, as observações pela Análise de Agrupamento. Foram utilizadas as cultivares BRS 122, CATISSOL e Helio 250. Foram grupados os valores de rendimento de aquênios em três classes, segundo os seguintes valores médios: rendimentos altos: 1995 kg ha-1; rendimentos médios: 1359 kg ha-1; rendimentos baixos: 961 kg ha-1. Os valores de rendimento de óleo também foram agrupados nas seguintes classes, segundo os seguintes valores médios: rendimentos altos: 927 kg ha-1; rendimentos médios: 543 kg ha-1; rendimentos baixos: 423 kg ha-1. A variabilidade dos rendimentos (aquênios e óleo) foi explicada pela variabilidade no número de aquênios por capítulo. Em 2008, a variabilidade no número de aquênios por capítulo esteve correlacionada à deficiência hídrica em R1-R4 e R4-R6 e aos teores de Ca, B e P no tecido foliar. Ocorreu inibição competitiva entre K e Mg, porém este fenômeno não esteve correlacionado à variabilidade do número de aquênios por capítulo. Ocorreu estresse hídrico durante o enchimento de aquênios, porém este não explicou a variabilidade no rendimento de aquênios e de óleo