Vibration Attenuation in Rotating Machines Using Smart Spring Mechanism

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Virulence attenuation and phenotypic variation of Paracoccidioides brasiliensis isolates obtained from armadillos and patients

Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, the most important systemic mycosis in Latin America. The virulence profiles of five isolates of P. brasiliensis were studied in two different moments and correlated with some colonial phenotypic aspects. We observed a significant decrease in the virulence and an intense phenotypic variation in the mycelial colony. The recognition of all ranges of phenotypic and virulence variation of P. brasiliensis, as well as its physiological and genetic basis, will be important for a better comprehension of its pathogenic and epidemiological features.

Attenuation of neuropsychiatric symptoms and caregiver burden in Alzheimer's disease by motor intervention: a controlled trial

OBJECTIVE: To analyze the effects of motor intervention on the neuropsychiatric symptoms of Alzheimer's disease and on the caregivers' burden. DESIGN: This is a controlled trial evaluating the effects of a motor intervention program on the neuropsychiatric symptoms. SETTING: The intervention was performed on community patients from two university centers specializing in physical exercise for the elderly. SUBJECTS: Patients with Alzheimer's disease were divided into two groups: sixteen received the motor intervention and sixteen controls (five controls were excluded because of clinical intercurrences). INTERVENTIONS: Aerobic exercises (flexibility, strength, and agility) and functional balance exercises were conducted over six months for 60 minutes three times per week. MAIN MEASURES: Psychopathological features of patients were evaluated with the Neuropsychiatric Inventory and Cornell Scale for Depression in Dementia. Caregivers were evaluated using the Neuropsychiatric Inventory-Distress and Burden Interview. A two-way analysis of variance (ANOVA) was applied to observe interactions (pre- vs. post-intervention; participants vs. controls). RESULTS: Patients from the intervention presented a significant reduction in neuropsychiatric conditions when compared to controls (Neuropsychiatric Inventory: F: 11.12; p = 0.01; Cornell Depression scale: F: 11.97; p = 0.01). The burden and stress of caregivers responsible for patients who participated in the intervention significantly decreased when compared to caregivers responsible for controls (Neuropsychiatric Inventory-Distress: F: 9.37; p = 0.01; Burden Interview: F: 11.28; p = 0.01). CONCLUSIONS: Aerobic exercise was associated with a reduction in the neuropsychiatric symptoms and contributed to attenuate the caregivers' burden. However, the researchers were not blinded to the patient's intervention status, which constitutes an important limitation of this study.

A note on the attenuation of the sommerfeld effect of a non-ideal system taking into account a MR damper and the complete model of a DC motor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of α-tocopherol, taurine and selenium on the attenuation of ischemia/reperfusion injury of splanchnic organs

Background: Splanchnic artery occlusion shock is caused by increased capillary permeability and cellular injury precipitated by oxygen derived free radicals following ischemia and reperfusion of splanchnic organs. The purpose of this study was to assess the role of several well-known oxygen- derived free radical scavengers in ameliorating or preventing this syndrome. Study design: Anesthetized rats were subjected to periods of occlusion of the visceral arteries and reperfusion. Tocopherol, taurine, selenium or a 'cocktail' of these three agents was injected subcutaneously for 4 consecutive days prior to operation. Mean arterial blood pressure was measured throughout the experimental period. Fluorometry and technetium-99m pyrophosphate counting of the visceral organs were performed as well as a histologic grading system for intestinal viability. Results: Final mean arterial blood pressure associated with the 'cocktail' and selenium groups was 79.1 ± 27.4 mmHg and 83.6 ± 17.8 mmHg, respectively. These values were significantly higher than the control group, 40.8 ± 11.4 mmHg (P < 0.05). Similar patterns of the benefit of selenium in contrast with the other groups were obtained with fluorescein perfusion, radioisotopic activity and histologic analysis. Conclusion: Pretreatment with selenium of splanchnic ischemia and reperfusion in the rat improves mean arterial blood pressure and microcirculatory visceral perfusion. Further analysis of the precise protective mechanism of selenium for reperfusion injury will enable visceral organs to withstand the consequences of increased capillary leakage and oxidant injury.

Evaluation of water amount in hydrated ethanol fuel by gamma-ray attenuation technique

In this work, is presented an alternative and non conventional technique for evaluate the water amount present in the hydrated ethanol used as automotive fuel. The standard technique used in this kind of measure is the use of densimeter. The proposal of this work is based on the measure of the linear attenuation coefficient of hydrated ethanol, using the gamma-ray attenuation technique. The water amount, in volume, can be determined knowing the linear attenuation coefficient of hydrated ethanol. Samples of hydrated ethanol, collected at fuel stations, located in Sorocaba, SP, Brazil, were analyzed and the results showed the feasibility of the technique. © 2011 American Institute of Physics.

LED light attenuation through human dentin: A first step toward pulp photobiomodulation after cavity preparation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of Wave Attenuation in Buried Plastic Water Distribution Pipes

Leaks in pipes are a common issue encountered in the water industry. Acoustic methods are generally successful in finding and locating leaks in metallic pipes, however, they are less effective when applied to plastic pipes. This is because leak-noise signals are heavily attenuated due to high damping in the pipe-wall and sound radiation into the soil. As result, high frequency leak noise does not travel long distances. To determine how far leak noise may travel in a pipe at any frequency, the attenuation of the wave responsible for leak noise propagation should be known. In this paper a new method to estimate this is described. The method is then applied to some measurements made on a bespoke pipe-test rig in the UK, and the results are compared with theoretical predictions.

Using of a snap-through truss absorber in the attenuation of the sommerfeld effect

This work, considers a vibrating system, which consists of a snap-through truss absorber (STTA) coupled to an oscillator, under excitation of an DC motor, with an eccentricity and limited power, characterizing a non-ideal oscillator (NIO). It is aimed to use the absorber STTA, to establish the conditions, that we have the maxim attenuation of the jumpphenomenon (Sommerfeld Effect). Here, weare interestedin determining the conditions of the vibrating system, in which there arereduced amplitudes of the oscillator, when it passes through the region of resonance.

DYNAMICAL JUMP ATTENUATION IN A NON-IDEAL SYSTEM THROUGH A MAGNETORHEOLOGICAL DAMPER

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cerebellar tomographic attenuation of healthy felines

The cerebellum is responsible for coordination and maintenance of the fine control of muscle contraction. In cases of a suspected cerebellar disorder, a computed tomography scan can be performed to identify structural change. The aim of this study is to describe the cerebellar tomographic attenuation values in healthy cats since this variable is considered of great importance in the evaluation of images obtained by this imaging modality. A simple and a contrast enhanced brain computed tomographic scan were performed in 15 adult cats with no history of neurological symptoms and negative for feline leukemia and immunodeficiency virus. After acquiring the image, the measurement of the average attenuation of a cerebellar area of 2 centimeters in diameter was obtained. The cerebellar tomographic attenuation showed a variation from 14.60 to 25.50 HU in the simple scan and from 25.50 to 33.40 HU in the enhanced phase. Most animals (73.33%) had precontrast cerebellar attenuation values within the stipulated limit for the brain in a previous study (20-41 HU). Four animals in this study (26.67%) had values lower than 20 HU, which can be explained by differences in cellular composition between these two regions. The average value of contrast enhancement was 4.91 HU, and in none of the animals an enhancement greater than 10 HU was observed, which is in agreement with previous studies.

Effect of protective solutions and hydroxyethyl starch in the attenuation of the injuries of ischemia and reperfusion of splanchnic organs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of hourly global, direct and diffuse solar radiations attenuation as a function of optical air mass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Application of an auditory steady-state response test to evaluate the attenuation of hearing protection devices

This research aims to present a new method to get real attenuation of hearing protection devices, with good reproducibility and a small standard deviation, without relying on skills and cooperation individual. Thus the authors performed tests in 10 individuals without protection and after with two kinds of ear protections (ear plug and ear muffs), to get the threshold limit value in each of the 3 stages. For this, the research used an electrophysical exam, normally used in speech therapy, named ASSR (auditory steady-state response). The principle of this exam is put on individual’s head 3 electrodes, to capture electrical signs directly in auditory nerve. In summary, the authors presented the final results. The method proposed by ANSI (American National Standards Institute) indicated an attenuation of 27.6 dB for ear plugs, while the value found in this work was 16 dB; and for ear muffs, the ANSI method indicated 29.8 dB while the value found here was 28.5 dB.