Resistance Spot Welding of Dissimilar Steels: Temperature Curves

Resistance spot welding was used to joint AISI 316L austenitic stainless steel and AISI 1020 low carbon steel. During the welding process, temperature measurements were taken to obtain the temperature curves. Because of the different chemical compositions of the carbon steel and stainless steels, their thermal conductivity values are also different. Electrical resistivity is also an important parameter when carbon steel is spot welded to stainless steel. Differences in the thermal conductivity and in the electrical resistivity of metals lead to an asymmetrical weld nugget in the dissimilar joints. Dissimilar resistance spot welding can be more complex than similar welding due to different thermal cycle experienced with each metal

Experimental Determination of the Convective Coefficient of Heat Transfer Using the Global Capacitance Method

The heat transfer coefficient (h) is an extremely important variable in the evaluation of convective heat transfer, however, its determination is a great challenge due to the various factors that influence it: fluid viscosity, fluid density, specific heat of the fluid, thermal conductivity of the fluid, coefficient of volumetric expansion, fluid velocity. The objective of this work is the experimental determination of the convective heat transfer coefficient by means of the global capacitance method. Three test bodies, two cylindrical bodies and one spherical body were used. These specimens were individually heated in a stove, and heating was monitored by means of a thermocouple and a data logger. The results showed a good concordance between the values of h obtained experimentally and the literature

Antibacterial and antibiofilm activities of quercetin against clinical isolates of Staphyloccocus aureus and Staphylococcus saprophyticus with resistance profile

The aim of this study was to determine the antibacterial and antibiofilm properties of quercetin against clinical isolates of Staphyloccocus aureus and Staphylococcus saprophyticus with resistance profile. The antibacterial activity of quercetin was performed by the determination of the minimum inhibitory concentration (MIC) through the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The percentage of inhibition of Staphylococcus spp. biofilm, after treatment with sub-inhibitory concentrations of quercetin (MIC/2 and MIC/4), was evaluated by the violet crystal assay. Quercetin showed an antimicrobial activity against clinical isolates of methicillin-susceptible S. aureus (MSSA) (MIC = 250 µg/ml), methicillin-resistant S. aureus (MRSA) (MIC = 500 µg/ml), vancomycin-intermediate S. aureus (VISA) (MIC = 125 and 150 µg/ml), S. saprophyticus resistant to oxacillin (MIC = 62.5 to 125 µg/ml), vancomycin-resistant S. aureus (VRSA) and S. saprophyticus resistant to oxacillin and vancomycin (MIC = 500 to 1000 µg/ml). At MIC/2 and MIC/4 the quercetin inhibit 46.5 ± 2.7% and 39.4 ± 4.3% of the S. aureus biofilm, respectively, and 51.7 ± 5.5% and 46.9 ± 5.5% of the S. saprophyticus biofilm, respectively. According to the results of this study, it was noticed that the quercetin presented an antibacterial activity against strains of Staphylococcus spp. with resistance profile and also inhibited the bacterial biofilm production even in sub-inhibitory concentrations

The Brazilian Ceremony in Honor of Body Donors: An opportunity to express gratitude and reflect on medical education

Introduction: Memorial ceremonies are a way for institutions to show their gratitude for the gesture made by body donors and are an opportunity for students to reflect on the ethical paradigm shift. Therefore, this study aims to describe the memorial ceremony at the Federal University of Health Sciences of Porto Alegre and assess the perception of both students and the donors’ relatives regarding the event. Material and methods: In 2016, a questionnaire was applied to donors’ relatives with questions regarding structure of the ceremony, ethical training of the students and importance of body donation. Another questionnaire was applied to the first-year students of the medical school, with questions about understanding the use of bodies, and their thoughts on death and relevant ethical issues. Results: Fifty questionnaires were answered by family members and 98% agreed that the ceremony was an opportunity to feel closer to the donors and 100% said that the ceremony is important in the ethical training of students. Among students, 68 questionnaires were answered, and all affirmed that the event had a positive impact on the perception of physician-patient relationship and personal growth, and 86.7% reported enhanced empathy. Conclusion: The memorial ceremony seems to encourage students to reflect on ethical issues, because at the same time that the donors’ relatives perceive an attitude of care and respect on the part of the students, the students state a heightened sense of commitment and responsibility regarding their learning and professional formation, which depends on the gesture made by the donors

Fungos associados ao declínio da videira no Nordeste do Brasil.

Suplemento. Edição dos Resumos do 44 Congresso Brasileiro de Fitopatologia, Bento Gonçalves, ago. 2011

Mast cell repopulation of the peritoneal cavity: contribution of mast cell progenitors versus bone marrow derived committed mast cell precursors

<p>Abstract</p> <p>Background</p> <p>Mast cells have recently gained new importance as immunoregulatory cells that are involved in numerous pathological processes. One result of these processes is an increase in mast cell numbers at peripheral sites. This study was undertaken to determine the mast cell response in the peritoneal cavity and bone marrow during repopulation of the peritoneal cavity in rats.</p> <p>Results</p> <p>Two mast cell specific antibodies, mAb AA4 and mAb BGD6, were used to distinguish the committed mast cell precursor from more mature mast cells. The peritoneal cavity was depleted of mast cells using distilled water. Twelve hours after distilled water injection, very immature mast cells could be isolated from the blood and by 48 hours were present in the peritoneal cavity. At this same time the percentage of mast cells in mitosis increased fourfold. Mast cell depletion of the peritoneal cavity also reduced the total number of mast cells in the bone marrow, but increased the number of mast cell committed precursors.</p> <p>Conclusions</p> <p>In response to mast cell depletion of the peritoneal cavity, a mast cell progenitor is released into the circulation and participates in repopulation of the peritoneal cavity, while the committed mast cell precursor is retained in the bone marrow.</p

Desenvolvimento de dendezeiro em área reabilitada com leguminosas arbóreas.

O objetivo desse trabalho foi avaliar o desenvolvimento de 8 cultivares de dendê, plantadas em tanques de deposição de rejeito de bauxita, anteriormente com um substrato de cerca de 50 cm de cinza vegetal e revegetado com leguminosas arbóreas fixadoras de nitrogênio