16 research outputs found

    Mechansim and outcome of hip fracture: a multi-center study

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    Background: We aimed to demonstrate the mechanism of fracture and functional outcome of patients with hip injury in our clinical setting. Methods: In a historical cohort, all women 50 years of age and older admitted to three university hospitals of Tehran University of Medical Sciences (Shariati, Imam Khomeini and Sina) with the diagnosis of hip fracture from 21 March 2003 to 21 March 2004 were included in this study (n=115). Follow up was conducted via telephone post and even home visit to record the functional status of the patients at the time of study (5 Jan 2005) measured with Barthel index in addition to the exact mechanism of injuries. Results: The mean and standard deviation of age were 76.3 ± 10.6 years. About 88.7% of injuries had occurred at home (65.2% on the carpet), the remaining happening in the streets. Mean length of hospitalization was 11 ± 7.9 days. Among our patients, 71% could mobilize spontaneously without aids before injuries. This had reduced to 20% at the time of follow-up. The mean Barthel index was 97.2 ± 8.2 before fracture and 75 ± 21.1 at the present. Among our patients, five cases died during hospitalization and 29 of them died afterwards (total: 34 or 29.6%). Conclusion: The most common external cause of injuries in our cases was stumbling at home especially on carpeted surfaces. This necessitates preventive measures aimed at physical standards of houses and education of elderly on healthy locomotion, indoors

    Investigation of the storage and release of oxygen in a Cu-Pt element of a high-temperature microcombustor

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    A miniature combustor for converting organic samples into CO2 with application in carbon isotopic measurements has been manufactured and evaluated. The combustor was made of High-Temperature Co-fired Ceramic (HTCC) alumina green tapes. The device has a built-in screen printed heater and a temperature sensor made of platinum, co-sintered with the ceramic. A copper oxide oxygen supply was added to the combustor after sintering by in-situ electroplating of copper on the heater pattern followed by thermal oxidation. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Thermal Gravimetric Analysis (TGA) were used to study electroplating, oxidation and the oxide reduction processes. The temperature sensor was calibrated by use of a thermocouple. It demonstrates a temperature coefficient resistance of 4.66×10−3/°C between 32 and 660 °C. The heat characterization was done up to 1000 °C by using IR thermography, and the results were compared with the data from the temperature sensor. Combustion of starch confirmed the feasibility of using copper oxide as the source of oxygen of combustion

    Characterization of dielectric properties of polycrystalline aluminum nitride for high temperature wireless sensor nodes

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    An aluminium nitride (AlN) passive resonance circuit intended for thermallymatched high temperature wireless sensor nodes (WSN) was manufactured using thick-lmtechnology. Characterization was done for temperatures up to 900C in both a hot-chuck forfrequencies below 5 MHz, and using wireless readings of resonating circuits at 15 MHz, 59 MHz,and 116 MHz. The substrate for the circuits was sintered polycrystalline AlN. Using a simpliedmodel for the resonators where the main contribution of the frequency-shift was considered tocome from a shift of the dielectric constant for these frequencies, the temperature dependency ofthe dielectric constant for AlN was found to decrease with increasing frequency up to 15 MHz.With an observed frequency shift of 0.04% at 15 MHz, and up to 0.56% at 59 MHz over atemperature range of 900C, AlN looks as a promising material for integration of resonancecircuits directly on the substrate

    Thermomechanical stability and integrability of an embedded ceramic antenna with an integrated sensor element for wireless reading in harsh environments

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    This paper reports on the design, manufacturing and evaluation of a small, wirelessly powered and read resonating antenna circuit with an integrated pressure sensor. The work aims at developing miniature devices suitable for harsh environments, where high temperature prevents the use of conventional, silicon-based microdevices. Here, the device is made of alumina with platinum as conducting material. Ceramic green tapes were structured using high-precision milling, metallized using screen printing, and subsequently laminated to form stacks before they were sintered. The device’s frequency shift as a function of temperature was studied up to 900°C. The contributions to the shift both from the thermomechanical deformation of the device at large, and from the integrated and, so far, self-pressurized sensor were sorted out. A total frequency shift of 3200 ppm was observed for the pressure sensor for heating over the whole range. Negligible levels of thermally induced radius of curvature were observed. With three-point bending, a frequency shift of 180 ppm was possible to induce with a curvature of radius of 220 m at a 10 N load. The results indicate that a robust pressure sensor node, which can register pressure changes of a few bars at 900°C and wirelessly transmit the signal, is viable

    One-year prevalence of antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus recovered from raw meat

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    Food with animal origins and especially meat may play an important role in transmission of methicillin-resistant strains of Staphylococcus aureus to humans. The present investigation was carried out to determine the prevalence of MRSA in various types of Iranian meat samples as well as study their antimicrobial resistance properties. Nine-hundred raw meat samples were collected during various months of the year. Samples were cultured and those that were MRSA-positive were subjected to the disk diffusion method to study the antibiotic resistance pattern. One-hundred and sixty out of 900 raw meat samples (17.7%) were positive for MRSA. Raw sheep meat samples had the highest (24.0%), while raw camel meat samples had the lowest (10%) prevalence of MRSA. Samples which were collected in June, July, August, September and June months had the highest prevalence of MRSA. Bacterial strains were also resistant to ampicillin (100%), penicillin G (100%), gatifloxacin (96.8%), ceftriaxone (80%) and oxacillin (76.2%) antibiotics. We found that only one isolate was resistant to all tested antimicrobial agents. Contaminated meat samples are potential risk factor for transmission of MRSA. Thoughtful antibiotics prescription, control the hygienic quality of meat inspections and increase the hygienic status of butchers and slaughterhouses can decrease the prevalence of MRSA in meat
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