On the major role played by the lumen curvature of intracranial aneurysms walls in determining their mechanical response, local hemodynamics, and rupture likelihood.

The properties of intracranial aneurysms (IAs) walls are known to be driven by the underlying hemodynamics adjacent to the IA sac. Different pathways exist explaining the connections between hemodynamics and local tissue properties. The emergence of such theories is essential if one wishes to compute the mechanical response of a patient-specific IA wall and predict its rupture. Apart from the hemodynamics and tissue properties, one could assume that the mechanical response also depends on the local morphology, more specifically, the curvature of the luminal surface, with larger values at highly-curved wall portions. Nonetheless, this contradicts observations of IA rupture sites more often found at the dome, where the curvature is lower. This seeming contradiction indicates a complex interaction between the hemodynamics adjacent to the aneurysm wall, its morphology, and mechanical response, which warrants further investigation. This was the main goal of this work. We accomplished this by analyzing the stress and stretch fields in different regions of the wall for a sample of IAs, which have been classified based on particular hemodynamics conditions and lumen curvature. Pulsatile numerical simulations were performed using the one-way fluid-solid interaction strategy implemented in OpenFOAM (solids4foam toolbox). We found that the variable best correlated with regions of high stress and stretch was the lumen curvature. Additionally, our data suggest a connection between the local curvature and particular hemodynamics conditions adjacent to the wall, indicating that the lumen curvature is a property that could be used to assess both mechanical response and hemodynamic conditions, and, moreover, suggest new rupture indicators based on the curvature.

A numerical investigation of the mechanics of intracranial aneurysms walls: Assessing the influence of tissue hyperelastic laws and heterogeneous properties on the stress and stretch fields.

Numerical simulations have been extensively used in the past two decades for the study of intracranial aneurysms (IAs), a dangerous disease that occurs in the arteries that reach the brain and affect overall 3.2% of a population without comorbidity with up to 60% mortality rate, in case of rupture. The majority of those studies, though, assumed a rigid-wall model to simulate the blood flow. However, to also study the mechanics of IAs walls, it is important to assume a fluid-solid interaction (FSI) modeling. Progress towards more reliable FSI simulations is limited because FSI techniques pose severe numerical difficulties, but also due to scarce data on the mechanical behavior and material constants of IA tissue. Additionally, works that have investigated the impact of different wall modeling choices for patient-specific IAs geometries are a few and often with limited conclusions. Thus our present study investigated the effect of different modeling approaches to simulate the motion of an IA. We used three hyperelastic laws - the Yeoh law, the three-parameter Mooney-Rivlin law, and a Fung-like law with a single parameter - and two different ways of modeling the wall thickness and tissue mechanical properties - one assumed that both were uniform while the other accounted for the heterogeneity of the wall by using a "hemodynamics-driven" approach in which both thickness and material constants varied spatially with the cardiac-cycle-averaged hemodynamics. Pulsatile numerical simulations, with patient-specific vascular geometries harboring IAs, were carried out using the one-way fluid-solid interaction solution strategy implemented in solids4foam, an extension of OpenFOAM®, in which the blood flow is solved and applied as the driving force of the wall motion. We found that different wall morphology models yield smaller absolute differences in the mechanical response than different hyperelastic laws. Furthermore, the stretch levels of IAs walls were more sensitive to the hyperelastic and material constants than the stress. These findings could be used to guide modeling decisions on IA simulations, since the computational behavior of each law was different, for example, with the Yeoh law being the fastest to converge.

Feed-out rate used as a tool to manage the aerobic deterioration of corn silages in tropical and temperate climates.

There is an increasing recognition throughout the world that many of the feeding problems of dairy herds are linked to the presence of aerobically deteriorated parts on a silo face, causing farmers to pose questions on what amount of silage should be removed daily to feed their animals. Since an adequate feed-out rate helps to prevent silage spoilage, a simple tool is needed to manage the aerobic deterioration of corn silages during feed-out. The aims of this study were to develop an unloading rate index, which we have called the mass feed-out rate (MFR), expressed in kilograms of fresh matter silage unloaded daily per square meter of silo face, to better predict the aerobic deterioration of silage and to offer management solutions to help prevent spoilage, through a survey on 97 commercial dairy farms in Italy and Brazil. Silages were sampled and analyzed for their main microbial, fermentative, and nutritional characteristics, whereas silage temperatures were measured in the core and peripheral areas of the silo working face. Moreover, a detailed questionnaire on silo management and silage utilization was administered to the farmers during each farm visit. The size and silage density of the silos presented a wide variability in the 2 countries, thus indicating that different management practices were adopted during corn harvesting, silo filling, and silage compaction. The differences between pH and temperature in the peripheral areas and in the core of the silage (dpH and dT, respectively) were tested as a single indicator to identify any aerobic deteriorated areas on the silo face, associated with the yeast and mold counts. Both indicators correctly identified aerobic deterioration in 86.6% and 93.8% of the studied silos, respectively. The lactic acid and ethanol increased as the MFR increased, whereas the starch, dT, and the yeast and mold counts decreased with increasing MFR. A daily removal rate of over 250 kg of silage/m2 markedly reduced the risk of spoilage in corn silages at a farm level in both temperate and tropical environments. The new MFR index can substitute for the commonly used linear feed-out rate as it includes the silage density and can be obtained from 1 single recording.

Supplementation of lamb ewes with different protein sources in deferred marandu palisadegrass (Brachiaria brizantha cv. marandu) pasture / [Suplementação de matrizes ovinas com diferentes fontes de proteína em pasto diferido de capim-marandu (Brachiaria brizantha cv. Marandu)]

The objective of this study was to evaluate the effect of different protein sources on the performance of lamb ewes and their offspring supplemented in deferred pasture. The treatments were the different protein sources: soybean meal, cotton cake, babassu cake and coconut cake. The ewes were weighed and evaluated for their body condition score during the gestation, parturition and weaning phases. The lambs were weighed at birth and at weaning. The structural variables and chemical composition of the pasture were evaluated during the usage period. Grass height and forage mass were higher when the ewes were in the gestation and weaning stages. The leaf mass was not altered during the pasture usage with a mean value of 566.1kg ha-1 DM. The highest levels of crude protein in the leaf blade were observed during the parturition and weaning phases. The body weight of the ewes did not differ between the sources with averages 45.0, 39.9 and 36.6kg for the gestation, parturition and weaning phases, respectively. Weights at birth and at weaning had an effect from protein sources, with the highest values observed in the lambs of ewes who received soybean meal and babassu cake supplementation. The lambs of ewes supplemented with soybean had higher average daily gain and total gain. Babassu, coconut and cotton cakes can replace soybean meal in supplementation of ewes in deferred pasture.(AU)

O objetivo deste estudo foi avaliar o efeito de diferentes fontes de proteína no desempenho de ovelhas e suas crias suplementadas em pastagem diferida. Os tratamentos foram as diferentes fontes proteicas: farelo de soja, tortas de algodão, babaçu e coco. As ovelhas foram pesadas e avaliadas quanto ao escore de condição corporal durante as fases de gestação, parição e desmame. Os cordeiros foram pesados no nascimento e no desmame. As variáveis estruturais e a composição química do pasto foram avaliadas durante o período de uso. A altura do dossel e a massa de forragem foram maiores quando as ovelhas estavam nas fases de gestação e desmame. A massa foliar não foi alterada durante o uso do pasto, com um valor médio de 566,1kg ha-1 MS. Os maiores teores de proteína bruta na lâmina foliar foram observados durante as fases de parto e desmame. O peso corporal das ovelhas não diferiu entre as fontes proteicas, com médias de 45,0, 39,9 e 36,6kg para as fases de gestação, parto e desmame, respectivamente. Os pesos ao nascimento e ao desmame tiveram efeito das fontes proteicas, com os maiores valores observados nos cordeiros de ovelhas que receberam suplementação com farelo de soja e torta de babaçu. Os cordeiros suplementados com soja apresentaram maior ganho médio diário e ganho total. As tortas de babaçu, coco e algodão podem substituir o farelo de soja na suplementação de ovelhas em pastagem diferida.(AU)

Anthranilate synthase subunit organization in Chromobacterium violaceum.

Tryptophan is an aromatic amino acid used for protein synthesis and cellular growth. Chromobacterium violaceum ATCC 12472 uses two tryptophan molecules to synthesize violacein, a secondary metabolite of pharmacological interest. The genome analysis of this bacterium revealed that the genes trpA-F and pabA-B encode the enzymes of the tryptophan pathway in which the first reaction is the conversion of chorismate to anthranilate by anthranilate synthase (AS), an enzyme complex. In the present study, the organization and structure of AS protein subunits from C. violaceum were analyzed using bioinformatics tools available on the Web. We showed by calculating molecular masses that AS in C. violaceum is composed of alpha (TrpE) and beta (PabA) subunits. This is in agreement with values determined experimentally. Catalytic and regulatory sites of the AS subunits were identified. The TrpE and PabA subunits contribute to the catalytic site while the TrpE subunit is involved in the allosteric site. Protein models for the TrpE and PabA subunits were built by restraint-based homology modeling using AS enzyme, chains A and B, from Salmonella typhimurium (PDB ID 1I1Q).

Eficácia do diltiazem em hipertensos moderados. Avaliaçäo utilizando parâmetros obtidos pela monitoraçäo ambulatorial da pressäo arterial em 24h (M.A.P.A.) / Efficacy of diltiazem in moderate arterial hypertension. Evaluation through 24-hour ambulatory blood pressure monitoring (ABPM)

Os parâmetros obtidos pela MAPA foram analisados em 15 pacientes portadores de hipertensäo arterial primária, de forma moderada, sem prévio tratamento, e comparados com aqueles obtidos após 4 semanas em uso de diltiazem, 180 mg (formulaçäo Retard) diários, ingeridos às 8h da manhä. Observou-se reduçäo significativa dos níveis tensionais (sistólicos e diastólicos ) e da carga pressórica, importante atuaçào no descenso noturno (restaurando o ritmo circadiano noturno) e significativa açäo na ascensäo tinal, propiciando rampa de ascensäo mais suave e significativa reduçäo do duplo produto, principalmente no horário das 6h às 7h. Näo foi observada modificaçäo significativa quanto ao índice de reatividade vascular, e houve aumento da variabilidade sisto-diastólica após uso da medicaçäo.

Análise da monitorizaçäo ambulatorial de pressäo arterial em hipertensos leves / Analysis of ambulatory blood pressure monitoring in mild hypertensive patients

Os autores analisam a curva pressórica obtida pela Monitorizaçäo Ambulatorial da Pressäo Arterial (M. A. P. A) em 15 pacientes hipertensos primários brancos, forma leve, sem comprometimento de orgäos alvos, e observam que os valores tencionais säo inferiores àqueles observados pela aferiçäo casual. Sugerem que a variabilidade e a carga pressórica possam ser fatores preditivos e prognósticos da doença hipertensiva e mostram a importância da ascensäo matinal, demonstrando que o horário de pico é entr6 e 7 horas, e demonstram que o incremento do duplo produto observado neste período é preponderamente devido ao aumento da frequência cardíaca do que ao aumento da pressäo arterial.

Clinical evaluation of d-2-(6'-methoxy-2'-naphthyl)propionic acid (naproxen) in rheumatic conditions.

A double-blind, crossover trial with 40 patients suffering from classic or definite rheumatoid arthritis was undertaken to obtain a clinical evaluation of naproxen in the disease. Each patient received either naproxen (500 mg/day) or placebo for 20 days and was then switched to the other compound for 20 days. For final evaluation, 22 cases were eliminated for various reasons, leaving 18 patients: seven cases of classical rheumatoid arthritis and 11 cases of definite rheumatoid arthritis. Optimum or very good efficacy of the active compound was present in 66.6 per cent of the cases versus 11.1 per cent of the placebo group. Doubtful or nil activity was observed in 66.6 per cent of the cases receiving placebo versus 16.6 per cent for naproxen. In addition, of the 22 cases that were eliminated from the final evaluation, but which were seen for the first ten-day follow-up visit while taking the active drug, optimum or very good efficacy was seen in 13. Therefore, this trial showed that naproxen achieved antiinflammatory and analgesic activity far superior to that observed with placebo.