589 research outputs found
Numerical simulation of the flow inside a horizontal closed refrigerated display cabinet
A refrigerated display cabinet is a device often used to preserve the products contained inside while enabling the costumer to have a view to the products stored. The main objective of this work was to investigate, using the ANSYS Fluent software, the airflow in a horizontal closed refrigerated display cabinet to better understand the fluid flow behavior in its interior. The turbulent airflow and non-isothermal heat transfer process were computed in a 2D transient state mathematical model where the basic equations governing the transport phenomena inside of the refrigerated display cabinet were solved. Regarding the turbulence model, this was modeled with the three-equation model since it can address the boundary-layer transition regions within the cabinet. After a complete understanding of the fluid flow behavior inside the cabinet, the influence of the door opening was analyzed. Results of the CFD simulations allowed to achieve a detailed mapping of the cooling process inside the equipment. Generally, stabilizing the interior temperature for an empty cabinet is rapidly achieved with minimal heat losses. The inclusion of products that are at a higher temperature than the cooling air creates a zone of high thermal inertia and makes the temperature stabilization a longer process. Even though specific equipment is used, the results provide standard information on the phenomena occurring inside the cabinet and contribute to the industry and academic society to understand and improve industrial products and obtain more information that is very reduced in the literature.This work has been supported by the Portuguese Foundation for Science and Technology (FCT) within the R&D Units Project Scope UIDB/00319/2020 (ALGORITMI) and R&D Units Project Scope UIDP/04077/2020 (METRICS). The first author would like to express his gratitude for the support given by the FCT through the PhD Grant SFRH/BD/130588/2017
Detection and phylogenetic analysis of Orf virus from sheep in Brazil: a case report
<p>Abstract</p> <p>Background</p> <p><it>Orf virus </it>(ORFV), the prototype of the genus <it>Parapoxvirus </it>(PPV), is the etiological agent of contagious ecthyma, a severe exanthematic dermatitis that afflicts domestic and wild small ruminants. Although South American ORFV outbreaks have occurred and diagnosed there are no South American PPV major membrane glycoprotein B2L gene nucleotide sequences available.</p> <p>Case presentation</p> <p>an outbreak of ovine contagious ecthyma in Midwest Brazil was investigated. The diagnosis was based on clinical examinations and molecular biology techniques. The molecular characterization of the virus was done using PCR amplification, cloning and DNA sequencing of the B2L gene. The phylogenetic analysis demonstrated a high degree of identity with ORFV strains, and the isolate was closest to the ORFV-India 82/04 isolate. Another Brazilian ORFV isolate, NE1, was sequenced for comparative analysis and also showed a high degree of identity with an Asian ORFV strain.</p> <p>Conclusion</p> <p>Distinct ORFV strains are circulating in Brazil. This is the first report on the phylogenetic analysis of an ORFV in South America.</p
Variabilidade temporal da posição dos bancos arenosos da praia do Cassino (RS): uma análise atravĂ©s de imagens de vĂdeo
Beaches are dynamic systems where natural elements like winds, water waves and sand interact resulting in complex hydrodynamical and sedimentary processes. Among the many morphological features presented at those environment, the sandbars are one of the most common features. In this context the main objective of the present study was to discuss the Cassino beach (RS) sandbars behavior at different temporal scales using for such purpose a two years time series of their position. To achieve the main goal, this paper used remote sense techniques such as video imaging. Analysis of the time series showed that Cassino beach presents a multiple bar system composed mainly by three bars. In addition, the emergence of a new bar by the split of the second (intermediate) one in two was observed, in an unprecedented manner in the scientific literature. During this period of time, before the total disappearance of the most offshore sandbar, the system was characterized as a four sandbars system. The analysis also indicated the presence of different temporal components such as seasonal, sub-seasonal, monthly and weekly components, in which the last has the greatest representation of the total variance as well as a significant correlation with significant wave height variability.As praias constituem sistemas dinâmicos onde ondas, marĂ©s, correntes e ventos interagem com sedimentos resultando em complexos processos hidro e morfodinâmicos, sendo os bancos arenosos uma das feições mais comuns nesses ambientes. O principal objetivo do presente trabalho foi analisar a variabilidade temporal da posição dos bancos da praia do Cassino (RS) com base em observações de alta resolução espaço-temporal utilizando tĂ©cnicas de vĂdeo imageamento. A base de dados utilizada compreende o perĂodo entre abril de 2005 atĂ© abril de 2007. Os resultados indicam que a praia do Cassino Ă© formada por um sistema de mĂşltiplos bancos, com ocorrĂŞncia mais comum de trĂŞs bancos. Em especial foi registrado um evento de surgimento de um banco a partir da divisĂŁo do banco intermediário, acompanhado da gradual migração do banco externo costa afora atĂ© seu desaparecimento. Durante este processo a praia apresentou quatro bancos. As sĂ©ries de dados indicaram diferentes componentes temporais, entre elas a subsazonal, a sazonal, a mensal e a semanal, sendo que esta Ăşltima demonstrou maior representatividade na variabilidade total dos dados, apresentando ainda correlação significativa com a variabilidade diária da altura das ondas
Reactivity of paraquat with sodium salicylate: formation of stable complexes
Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the antithrombogenic
properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2–3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS)
and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the chargetransfer complexes withm/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ
Multiparameter probability distributions for heavy rainfall modeling in extreme southern Brazil
AbstractStudy regionThe study was conducted in the Rio Grande do Sul state – Brazil.Study focusStudies about heavy rainfall events are crucial for proper flood management in river basins and for the design of hydraulic infrastructure. In Brazil, the lack of runoff monitoring is evident, therefore, designers commonly use rainfall intensity–duration–frequency (IDF) relationships to derive streamflow-related information. In order to aid the adjustment of IDF relationships, the probabilistic modeling of extreme rainfall is often employed. The objective of this study was to evaluate whether the GEV and Kappa multiparameter probability distributions have more satisfying performance than traditional two-parameter distributions such as Gumbel and Log-Normal in the modeling of extreme rainfall events in southern Brazil. Such distributions were adjusted by the L-moments method and the goodness-of-fit was verified by the Kolmogorov–Smirnov, Chi-Square, Filliben and Anderson–Darling tests.New hydrological insights for the regionThe Anderson–Darling and Filliben tests were the most restrictive in this study. Based on the Anderson–Darling test, it was found that the Kappa distribution presented the best performance, followed by the GEV. This finding provides evidence that these multiparameter distributions result, for the region of study, in greater accuracy for the generation of intensity–duration–frequency curves and the prediction of peak streamflows and design hydrographs. As a result, this finding can support the design of hydraulic structures and flood management in river basins
Microtiming patterns and interactions with musical properties in Samba music
In this study, we focus on the interaction between microtiming patterns and several musical properties: intensity, meter and spectral characteristics. The data-set of 106 musical audio excerpts is processed by means of an auditory model and then divided into several spectral regions and metric levels. The resulting segments are described in terms of their musical properties, over which patterns of peak positions and their intensities are sought. A clustering algorithm is used to systematize the process of pattern detection. The results confirm previously reported anticipations of the third and fourth semiquavers in a beat. We also argue that these patterns of microtiming deviations interact with different profiles of intensities that change according to the metrical structure and spectral characteristics. In particular, we suggest two new findings: (i) a small delay of microtiming positions at the lower end of the spectrum on the first semiquaver of each beat and (ii) systematic forms of accelerando and ritardando at a microtiming level covering two-beat and four-beat phrases. The results demonstrate the importance of multidimensional interactions with timing aspects of music. However, more research is needed in order to find proper representations for rhythm and microtiming aspects in such contexts
Impact of COVID-19 on healthcare-associated infections: Antimicrobial consumption does not follow antimicrobial resistance
Background: This study aimed to analyze the Healthcare-Associated Infections (HAI) rates and antimicrobial consumption in Intensive Care Units (ICU) in SĂŁo Paulo city during the COVID-19 pandemic and compare them with the pre-pandemic period.
Methods: This cohort included all hospitals that reported HAI rates (Central-Line-Associated Bloodstream Infection ‒ CLABSI and Ventilator-Associated Pneumonia ‒ VAP), the proportion of microorganisms that caused CLABSI, the proportion of resistant microorganisms, and antimicrobial consumption from January 2017 ‒ December 2020. Hospitals were stratified by the number of beds, Central Venous Catheter (CVC) utilization rate, Mechanical-Ventilation (MV) utilization rate, and type of funding. Statistical analyses were based on time-series plots and regression models.
Results: 220 ICUs were included. The authors observed an abrupt increase in CLABSI rates after the pandemic onset. High CLABSI rates during the pandemic were associated with hospital size, funding (public and non-profit private), and low CVC use (≤ 50%). An increase in VAP rates was associated with public hospitals, and high MV use (> 35%). The susceptibility profile of microorganisms did not differ from that of the pre-pandemic period. polymyxin, glycopeptides, and antifungal use increased, especially in COVID-19 ICUs.
Conclusions: HAI increased during COVID-19. The microorganisms’ susceptibility profile did not change with the pandemic, but the authors observed a disproportionate increase in large-spectrum antimicrobial drug use
Modulatory antimicrobial activity of Piper arboretum extracts (Zingiberaceae)
The side effects of certain antibiotics have been a recent dilemma in the medical arena. Due this fact, the necessity of natural product discovery could provide important indications against several pharmacological targets and combat many infectious agents. Piper arboreum Aub. (Piperaceae) has been used by Brazilian traditional communities against several illnesses including rheumatism, bronchitis, sexually transmitted diseases and complaints of the urinary tract. Medicinal plants are a source of several remedies used in clinical practice to combat microbial infections. In this study, ethanol extract and fractions of Piper arboreum leaves were used to assay antimicrobial and modulatory activity. The minimum inhibitory concentration (MIC) was determined using microdilution method of ethanol extract and fractions from the leaves of P. arboreum ranging between 8 and 1024 mgmL–1. The capacity of these natural products to enhance the activity of antibiotic and antifungal drugs was also assayed. In these tests, natural products were combined with drugs. The natural products assayed did not demonstrate any clinically relevant antimicrobial activity (MIC ³ 1024 mg mL–1). However, the modulation of antibiotic activity assay observed a synergistic activity of natural products combined with antifungal (such as nystatin and amphotericin B) and antibiotic drugs (such as amikacin, gentamicin and kanamycin). According to these results, these natural products can be an interesting alternative not only to combat infectious diseases caused by bacteria or fungi, but also to combat enhanced resistance of microorganisms to antibiotic and antifungal drugs
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