A Novel Design of a Torsional Shape Memory Alloy Actuator for Active Rudder.

SMA actuators are a group of lightweight actuators that offer advantages over conventional technology and allow for simple and compact solutions to the increasing demand for electrical actuation. In particular, an increasing number of SMA torsional actuator applications have been published recently due to their ability to supply rotational motion under load, resulting in advantages such as module simplification and the reduction of overall product weight. This paper presents the conceptual design, operating principle, experimental characterization and working performance of torsional actuators applicable in active rudder in aeronautics. The proposed application comprises a pair of SMA torsion springs, which bi-directionally actuate the actuator by Joule heating and natural cooling. The experimental results confirm the functionality of the torsion springs actuated device and show the rotation angle of the developed active rudder was about 30° at a heating current of 5 A. After the design and experiment, one of their chief drawbacks is their relatively slow operating speed in rudder positioning, but this can be improved by control strategy and small modifications to the actuator mechanism described in this work.

Strategy for Calculating Magnesium Sulfate Dose in Obese Patients: A Randomized Blinded Trial.

Background: Magnesium sulfate has analgesic properties during the postoperative period. However, there is a knowledge gap in pharmacology related to the use of the real, ideal, or corrected ideal body weight to calculate its dose in obese patients. This trial compared postoperative analgesia using actual and corrected ideal body weight. Methods: Seventy-five obese patients scheduled to undergo laparoscopic gastroplasty or cholecystectomy under general anesthesia were randomly assigned to three groups. The patients in the control group did not receive magnesium sulfate; the other two groups received magnesium sulfate at 40 mg·kg-1 of actual body weight or corrected ideal body weight. Results: In patients with body mass index >30 mg·kg-2 (mean body mass index ranging from 32.964 kg·m-2 to 33.985 kg·m-2, according to the groups) scheduled for video laparoscopic cholecystectomy, there were no differences in the blood magnesium concentrations in the groups receiving magnesium sulfate throughout the study, regardless of whether the strategy to calculate its dose was based on total or corrected ideal body weight. Patients in the groups receiving magnesium sulfate showed a significant reduction in morphine consumption (p ≤ 0.001) and pain scores (p=0.006) in the postoperative period compared to those in the control group. There were no significant differences in morphine consumption (p=0.323) or pain scores (p=0.082) between the two groups receiving magnesium sulfate. There were no differences in the total duration of neuromuscular block induced by cisatracurium among the three groups (p=0.181). Conclusions: Magnesium sulfate decreased postoperative pain and morphine consumption without affecting the recovery time of cisatracurium in obese patients undergoing laparoscopic cholecystectomy. Strategies to calculate the dose based on the actual or corrected ideal body weight had similar outcomes related to analgesia and the resulting blood magnesium concentration. However, as the sample in this trial presented body mass indices ranging from 30.11 kg·m-2 to 47.11 kg/m-2, further studies are needed to confirm these findings in more obese patients, easily found in centers specialized.

Analgesic effect of magnesium sulfate during total intravenous anesthesia: randomized clinical study.

INTRODUCTION AND OBJECTIVE: Opioids have usually been used as intraoperative analgesic components, regardless of the many adverse effects they are associated with, such as nausea, vomiting, respiratory depression, and hyperalgesia. Several approaches have been investigated to reduce doses used, and magnesium sulfate has been shown to be a valuable analgesic adjunct. The main objective of the present trial was to evaluate the effectiveness of magnesium sulfate as the chief intraoperative analgesic, and the secondary objectives were to assess propofol consumption, postoperative analgesia, and intraoperative hemodynamic stability. METHODS: In this prospective, double-blind trial, 50 patients scheduled to undergo post-bariatric abdominoplasty under general intravenous anesthesia were divided into two groups, to receive remifentanil or magnesium sulfate as intraoperative analgesic. Fentanyl 1 µg kg-1 was the rescue analgesic. RESULTS: Among the patients in the group receiving Magnesium Sulfate (MSG), 64% did not need supplemental analgesia and none of the patients in the Remifentanil Group (RG) required fentanyl. MSG patients showed propofol consumption 36.6% higher (guided by the Bispectral Index - BIS). MSG patients consumed significantly less ephedrine (mean ± SD) than RG patients, respectively 1.52 ± 4.38 mg and 10 ± 10.39 mg, p < 0.001. Mean values of blood concentrations of magnesium were comparable to values previously described in the literature. CONCLUSION: Magnesium sulfate is a safe and effective option for intraoperative analgesia, when avoiding or decreasing opioid use is required.

Frequency of osteopenia and osteoporosis in men and women living with HIV/Aids: an observational study / Frequência de osteopenia e osteoporose em homens e mulheres vivendo com HIV/Aids: um estudo observacional

ABSTRACT: Aims: To identify the frequency in changes of bone metabolism, including below the average value for age, osteopenia, and osteoporosis, in people living with HIV/AIDS (PLWHA) and to compare the frequency of factors associated with bone mineral density (BMD) and body composition between sex. Methods: This observational study assessed 106 PLWHA (65 male) recruited from the University Hospital of Ribeirão Preto Medical School from 2013 to 2014. BMD was measured using Dual Energy X-ray Absorptiometry (DXA). Standard deviation values for Z- and T-score proposed by the International Society for Clinical Densitometry were adopted to classify participants below the average value for age, osteopenia, and osteoporosis. Qui-square and Fischer's exact tests were employed to compare males and females based on their factors associated with BMD reduction. Results: Fifty-two (49%) PLWHA presented at least one diagnosis for below the average value for age, osteopenia, and osteoporosis, being 37 (57%) and 15 (37%) male and female, respec-tively. Frequency of alcohol consumption was higher in males (n=20; 30.8%) than females (n=05; 12.2%) (p=0.028).Conclusions: A high rate of PLWHA showed changes in bone metabolism, with a higher frequency in males. The fre-quency of alcohol consumption was higher in males, and it may partially explain the possible causes of the increased rates of bone metabolism changes observed in this group. This information may help develop strategies for reducing the frequency of diagnosis for below the average value for age, osteopenia, osteoporosis improving quality of life in PLWHA. (AU)

RESUMO: Objetivos: Identificar a frequência de alterações no metabolismo ósseo, incluindo valores abaixo do estimado para idade, osteopenia e osteoporose, em pessoas vivendo com HIV/Aids (PVHA) e comparar a frequência de fatores associados à redução da densidade mineral óssea (DMO) e composição corporal entre sexos. Métodos: Estudo observacional que ava-liou 106 PVHA (65 do sexo masculino) recrutadas do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo entre os anos 2013 e 2014. A DMO foi medida utilizando a Absorciometria Radiológica de Dupla Energia (DXA). Valores de desvio padrão Z- e T- scores propostos pela Sociedade Internacional para Densitometria Clí-nica foram adotados para classificar os participantes em abaixo do valor estimado para idade, osteopenia e osteoporose. Os testes do qui-quadrado e exato de Fischer foram empregados na comparação entre os sexos baseado em seus respec-tivos fatores associados à redução da densidade mineral óssea. Resultados: Cinquenta e dois (49%) PVHA apresentaram ao menos um diagnóstico para abaixo do valor estimado para idade, osteopenia e osteoporose, sendo 37 (57%) do sexo masculino e 15 (37%) feminino. A frequência de consumo de álcool foi maior no sexo masculino (n=20; 30,8%) compara-do ao feminino (n=5; 12,2%) (p=0,028). Conclusões: Uma alta taxa de PVHA apresentaram alterações no metabolismo ósseo, com maior frequência no sexo masculino. A frequência no consumo de álcool foi maior no sexo masculino, podendo explicar parcialmente as possíveis causas para taxa aumentada de alterações no metabolismo ósseo observada nesse grupo. Essa informação pode contribuir no desenvolvimento de estratégias para redução da frequência do diagnóstico para valores abaixo do estimado para idade, osteopenia e osteoporose, melhorando a qualidade de vida em PVHA

Rivaroxaban for treatment of intraventricular thrombus in Chagas disease.

Chagas disease leads to congestive heart failure, apical aneurysm, and may cause stroke or systemic embolism for intraventricular thrombus. We present a case of a 61-year-old man admitted for stroke 5 months after a renal embolism. An intraventricular thrombus was observed, probably the source of the cerebral and renal embolisms. The patient refused warfarin and rivaroxaban was used instead. After 40 days of treatment the thrombus had dissolved, after 20 months of regular use of rivaroxaban no more embolic events were observed. The use of rivaroxaban was effective in preventing embolic events in Chagas disease and intraventricular thrombus. .

Effects of Peracetic Acid on the Corrosion Resistance of Commercially Pure Titanium (grade 4)

The aim of this study was to evaluate the corrosion resistance of pure titanium grade 4 (cp-Ti-4), subjected to disinfection with 0.2% and 2% peracetic acid during different immersion periods using anodic potentiodynamic polarization test in acid and neutral artificial saliva. Cylindrical samples of cp-Ti-4 (5 mm x 5 mm) were used to fabricate 24 working electrodes, which were mechanically polished and divided into eight groups (n=3) for disinfection in 2% and 0.2% peracetic acid for 30 and 120 min. After disinfection, anodic polarization was performed in artificial saliva with pH 4.8 and 6.8 to assess the electrochemical behavior of the electrodes. A conventional electrochemical cell, constituting a reference electrode, a platinum counter electrode, and the working electrode (cp-Ti specimens) were used with a scanning rate of 1 mV/s. Three curves were obtained for each working electrode, and corrosion was characterized by using scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Data of corrosion potential (Ecorr) and passive current (Ipass) obtained by the polarization curves were analyzed statistically by Student's t-test (a=0.05). The statistical analysis showed no significant differences (p>0.05) between artificial saliva types at different concentrations and periods of disinfection, as well as between control and experimental groups. No surface changes were observed in all groups evaluated. In conclusion, disinfection with 0.2% and 2% peracetic acid concentrations did not cause corrosion in samples manufactured with cp-Ti-4.

Resumo O objetivo deste estudo foi avaliar a resistência à corrosão de titânio puro grau 4 (cp-Ti-4) submetido à desinfecção com ácido peracético a 0,2% e 2% durante diferentes períodos de imersão por meio do teste de polarização potenciodinâmica anódica em saliva artificial ácida e neutra. Amostras cilíndricas de cp-Ti-4 (5 mm x 5 mm) foram usadas para confeccionar 24 eletrodos de trabalho, os quais foram polidos mecanicamente e divididos em oito grupos (n=3) para desinfecção com ácido peracético a 2% e 0,2% por 30 e 120 minutos. Após a desinfecção, foi realizado o teste de a polarização anódica em saliva artificial com pH 4,8 e 6,8 para avaliar o comportamento eletroquímico dos eletrodos. Uma célula electroquímica convencional, composta por eletrodo de referência, contra-eletrodo de platina, e eletrodo de trabalho (amostras de cp-Ti) foi usada com taxa de varredura de 1 mV/s. Foram obtidas três curvas para cada eletrodo de trabalho e a corrosão foi analisada por microscopia eletrônica de varredura (MEV) e espectrometria de energia dispersiva de raios-X (EEDX). Os dados de potencial de corrosão (Ecorr) e corrente passiva (Ipass) obtidos com as curvas de polarização foram analisados estatisticamente pelo teste t de Student (=0,05). A análise estatística não mostrou diferenças significantes (p>0,05) entre os tipos de saliva artificial nas diferentes concentrações e períodos de desinfecção, bem como entre os grupos controle e experimental. Não foram observadas alterações nas superfícies das amostras de todos os grupos avaliados. Conclui-se que a desinfecção com ácido peracético nas concentrações de 0,2% e 2% não provocou corrosão nas amostras confeccionadas com cp-Ti-4.

Effects of Peracetic Acid on the Corrosion Resistance of Commercially Pure Titanium (grade 4).

The aim of this study was to evaluate the corrosion resistance of pure titanium grade 4 (cp-Ti-4), subjected to disinfection with 0.2% and 2% peracetic acid during different immersion periods using anodic potentiodynamic polarization test in acid and neutral artificial saliva. Cylindrical samples of cp-Ti-4 (5 mm x 5 mm) were used to fabricate 24 working electrodes, which were mechanically polished and divided into eight groups (n=3) for disinfection in 2% and 0.2% peracetic acid for 30 and 120 min. After disinfection, anodic polarization was performed in artificial saliva with pH 4.8 and 6.8 to assess the electrochemical behavior of the electrodes. A conventional electrochemical cell, constituting a reference electrode, a platinum counter electrode, and the working electrode (cp-Ti specimens) were used with a scanning rate of 1 mV/s. Three curves were obtained for each working electrode, and corrosion was characterized by using scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Data of corrosion potential (Ecorr) and passive current (Ipass) obtained by the polarization curves were analyzed statistically by Student's t-test (a=0.05). The statistical analysis showed no significant differences (p>0.05) between artificial saliva types at different concentrations and periods of disinfection, as well as between control and experimental groups. No surface changes were observed in all groups evaluated. In conclusion, disinfection with 0.2% and 2% peracetic acid concentrations did not cause corrosion in samples manufactured with cp-Ti-4.

The International Physical Activity Questionnaire-long form overestimates self-reported physical activity of Brazilian adults.

OBJECTIVE: To explore issues associated with measuring physical activity using the International Physical Activity Questionnaire (IPAQ)-long form in adults living in a mid-sized Brazilian city. METHODS: A stratified random sampling procedure was used to select a representative sample of adults living in Rio Claro. This yielded 1572 participants who were interviewed using the IPAQ-long form. The data were analysed using standard statistical procedures. RESULTS: Overall, 83% of men and 89% of women reported at least 150 min of combined moderate and/or vigorous physical activity per week. Reliable values of leisure and transportation-related physical activity were observed for both males and females. With regard to the household and work-related physical activity domains, both males and females reported unusually high levels of participation. CONCLUSION: The IPAQ-long form appears to overestimate levels of physical activity for both males and females, suggesting that the instrument has problems in measuring levels of physical activity in Brazilian adults. Accordingly, caution is warranted before using IPAQ data to support public policy decisions related to physical activity.

Evaluation of anodic behavior of commercially pure titanium in tungsten inert gas and laser welds.

PURPOSE: This study evaluated the resistance to corrosion in welds made with Tungsten Inert Gas (TIG) in specimens made of commercially pure titanium (cp Ti) in comparison with laser welds. MATERIALS AND METHODS: A total of 15 circular specimens (10-mm diameter, 2-mm thick) were fabricated and divided into two groups: control group-cp Ti specimens (n = 5); experimental group-cp Ti specimens welded with TIG (n = 5) and with laser (n = 5). They were polished mechanically, washed with isopropyl alcohol, and dried with a drier. In the anodic potentiodynamic polarization assay, measurements were taken using a potentiostat/galvanostat in addition to CorrWare software for data acquisition and CorrView for data visualization and treatment. Three curves were made for each working electrode. Corrosion potential values were statistically analyzed by the Student's t-test. RESULTS: Statistical analysis showed that corrosion potentials and passive current densities of specimens welded with TIG are similar to those of the control group, and had lower values than laser welding. TIG welding provided higher resistance to corrosion than laser welding. CONCLUSION: Control specimens welded with TIG were more resistant to local corrosion initiation and propagation than those with laser welding, indicating a higher rate of formation and growth of passive film thickness on the surfaces of these alloys than on specimens welded with laser, making it more difficult for corrosion to occur.

Malformação arteriovenosa dural do seio transverso-sigmóide causando neuralgia trigeminal / Transverse-sigmoid sinus dural arteriovenous malformation presenting as trigeminal neuralgia

Os autores relatam um caso raro de malformação arteriovenosa dural (MAVD) do seio transverso-sigmóide esquerdo, causando neuralgia do trigêmeo. O paciente foi submetido a cirurgia para esqueletização do seio transversosigmóide com ressecção dos dois terços distais do seio transverso e dos dois terços proximais do seio sigmóide. O procedimento cirúrgico foi suficiente para proporcionar a cura angiográfica e clínica, com um seguimento de oito meses. Foi realizada uma completa revisão bibliográfica encontrando-se apenas cinco casos descritos de pacientes com MAVD e neuralgia trigeminal.

The authors report a rare case of transverse-sigmoid dural arteriovenousmalformation (DAVM) presenting as trigeminal neuralgia in the distribution of left V3. The patient was treated surgically by the sinus skeletonization technique with the resection of the distal 2/3 of the transverse sinus and the proximal 2/3 of the sigmoid sinus. Clinical and angiographic cure was achieved in our patient with a folow-up of 8 months. Furthermore, a thorough review of the English language literature was carried out, compiling only five cases of trigeminal neuralgia due to DAVM.