Turbulent blood flow in a cerebral artery with an aneurysm.

Unruptured intracranial aneurysms are common in the general population, and many uncertainties remain when predicting rupture risks and treatment outcomes. One of the cutting-edge tools used to investigate this condition is computational fluid dynamics (CFD). However, CFD is not yet mature enough to guide the clinical management of this disease. In addition, recent studies have reported significant flow instabilities when refined numerical methods are used. Questions remain as to how to properly simulate and evaluate this flow, and whether these instabilities are really turbulence. The purpose of the present study is to evaluate the impact of the simulation setup on the results and investigate the occurrence of turbulence in a cerebral artery with an aneurysm. For this purpose, direct numerical simulations were performed with up to 200 cardiac cycles and with data sampling rates of up to 100,000 times per cardiac cycle. Through phase-averaging or triple decomposition, the contributions of turbulence and of laminar pulsatile waves to the velocity, pressure and wall shear stress fluctuations were distinguished. For example, the commonly used oscillatory shear index was found to be closely related to the laminar waves introduced at the inlet, rather than turbulence. The turbulence energy cascade was evaluated through energy spectrum estimates, revealing that, despite the low flow rates and Reynolds number, the flow is turbulent near the aneurysm. Phase-averaging was shown to be an approach that can help researchers better understand this flow, although the results are highly dependent on simulation setup and post-processing choices.

Antimicrobial resistance patterns of Staphylococcus spp. isolated from clinical specimens of companion animals in Northern Portugal, 2021-2023.

Staphylococcus spp. are growing pathogens in humans and companion animals. The emergence of multidrug-resistant bacterial infections, such as methicillin-resistant Staphylococcus-associated infections, due to zoonotic transmission, is a major public health concern. Domestic animals, such as dogs and cats, are possible reservoirs of multi-resistant bacterial species, which makes it relevant to monitor them due to their proximity to humans. However, there is a lack of information on the real scenario in Europe, especially in Portugal, particularly for animal infections caused by Staphylococcus spp. Therefore, this study aimed to investigate the antimicrobial resistance profile of Staphylococcus spp. isolated from cats and dogs diagnosed with infection in Northern Portugal. During 2021-2023, 96 Staphylococcus isolates from dogs and cats with symptoms of bacterial infection, including animals being treated in veterinary clinics/hospitals and cadavers submitted for necropsy at INIAV were included in the study collection. Of the 96 isolates, 63 were from dogs and 33 were Staphylococcus spp. from cats, most of which were isolated from ear (57% and 18%, respectively), skin (19 % and 27 %, respectively) and respiratory tract infections (6 % and 27 %, respectively). Among all the isolates, 12 different Staphylococcus spp. were identified, with Staphylococcus pseudintermedius being the most identified (61 % from dogs and 30 % from cats). It is noteworthy that 36 % of the isolates were multi-drug resistant and 25 % of the isolates showed a methicillin-resistant phenotype, with the mecA gene having been identified in all these isolates. This study highlights a high occurrence of multidrug-resistant Staphylococcus spp. in companion animals in Northern Portugal. This underlines the potential for cats and dogs to act as reservoirs of antimicrobial resistance, that can be transmitted to humans, posing a serious threat to public health.

Production and characterization of a milk-clotting protease produced in submerged fermentation by the thermophilic fungus Thermomucor indicae-seudaticae N31.

Proteases are some of the most important industrial enzymes, and one of their main applications is for the production of cheese in the dairy industry. Due to a shortage of animal rennet, microbial coagulant proteases are being sought. In this work, the production of microbial rennet from Thermomucor indicae-seudaticae N31 was studied in submerged fermentation. The best enzyme production was obtained in a fermentation medium containing 4 % wheat bran as the substrate in 0.3 % saline solution, incubated for 72 h at 45 °C and 150 rpm. The value of the milk clotting activity (MCA) was 60.5 U/mL, and the ratio to proteolytic activity (MCA/PA) was 510. The crude enzyme showed optimum pH at 5.5 and two peaks of optimum temperature (MCA at 65 °C and PA at 60 °C). The MCA was stable in the pH range 4.0-4.5 for 24 h and up to 55 °C for 1 h. It was stable during storage at different temperatures (-20 to 25 °C) for 10 weeks. Based on these results, we conclude that microbial rennet from T. indicae-seudaticae N31 produced by submerged fermentation showed good prospects of replacing traditional rennet.

Evaluation of dose due to ingestion of natural radionuclides of the uranium series in spring waters.

The concentrations of uranium isotopes and their decay products 226Ra, 222Rn, 210Pb and 210po have been analyzed in the mineral spring waters of a highly radioactive region of Brazil: Aguas da Prata. This region is located in the Poços de Caldas Plateau, one of the largest weathered alkaline intrusions in the world. Dose calculations were performed to evaluate the relative importance of these radionuclides in the exposure of the local population to radiation. Based upon concentrations measured in all the springs available, effective doses per year varying from 1.4 x 10(-4) mSv year(-1) for 238U to 5.1 x 10(-2) mSv year(-1) for 222Rn were observed. The doses from the ingestion of 222Rn, 210Po and 210Pb are of the same order of magnitude, and therefore these radionuclides are the most critical as far as the consumption of these waters is concerned.

Multiple immunoreactive forms of met- and leu-enkephalin in fetal and neonatal rat brain and in rat gut.

We have used radioimmunoassays with carboxyl-specific antisera to study the development of met- and leu-enkephalin in rat brain and gut from 13-days of fetal age through adulthood. Fractionation of HCl extracts of fetal and neonatal brain tissues by HPLC revealed the presence of immunoreactive forms other than met- and leu-enkephalin. For example, HPLC separation of extracts of 16-day fetal brain yielded two peaks of leu-enkephalin-like immunoreactivity. One emerged at the position of leu-enkephalin, the other eluted with about one-third the retention time. There were four peaks of met-enkephalin-like immunoreactivity, one with the retention time characteristic of met-enkephalin, the others with shorter retention times. In contrast, all of the met-enkephalin-like immunoreactivity in adult brain eluted with the retention time characteristic of authentic met-enkephalin and all of the leu-enkephalin-like immunoreactivity eluted in the position of authentic leu-enkephalin. Multiple immunoreactive forms of met- and leu-enkephalin were found in extracts of both fetal and adult gut tissues.