446 research outputs found

    Blunt Traumatic Hernia of Diaphragm With Late Presentation

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    Background: Diaphragmatic hernia after blunt trauma is an uncommon and often undiagnosed condition. Objectives: We aimed to review patients who presented with delayed blunt traumatic hernia of diaphragm. Patients and Methods: In this retrospective study, the medical records of six patients treated for blunt diaphragmatic hernias who were admitted to Kashan Shahid Beheshti hospital between June 2007 and June 2011 were analyzed. Results: Six patients with mean age of 41 years were included in the study. Male to female ratio was 2:1. Mean duration between trauma and admission to the hospital was 6.5 years (2 ā€“ 26 years). Five patients had left-sided diaphragmatic hernia. Chest X-ray was obtained from all patients which was diagnostic in 50 percent of the cases (n = 4). Additional diagnostic imaging with computerized tomography (CT) was used in six patients and upper gastrointestinal (GI) contrast study was performed in one patient. All patients underwent thoracotomy incision. Mesh repair was utilized in one patient. The mean hospitalization time was 14.1 days. There was one postoperative death (16.7%). Conclusions: Late presentation of blunt diaphragmatic hernia is an uncommon and challenging situation for the surgeon. Prompt diagnosis and treatment prevent serious morbidity and mortality associated with complications such as gangrene and perforation of herniated organ

    Hot deformation behavior and flow stress modeling of Tiā€“6Alā€“4V alloy produced via electron beam melting additive manufacturing technology in single Ī²-phase field

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    The hot working behaviour of additively manufactured Tiā€“6Alā€“4V pre-forms by Electron Beam Melting (EBM) has been studied at temperatures of 1000ā€“1200 Ā°C and strain rates of 0.001ā€“1 sāˆ’1. As a reference, a wrought Tiā€“6Alā€“4V alloy was also analyzed as same as the EBM one. In order to investigate the hot working behaviour of these samples, all the data evaluations were carried out step by step, and the stepwise procedure was discussed. No localized strain as a consequence of shear band formation was found in the samples after the hot compression. The flow stress curves of all the samples showed peak stress at low strains, followed by a regime of flow softening with a near-steady-state flow at large strains. Interestingly, it is found that the initial microstructure and porosity content as well as the chemistry of material (e.g. oxygen content) as being possible contributors to the lower level of flow stress that could be beneficial from the industrial point of view. The flow softening mechanism(s) were discussed in detail using the microstructure of the specimens before and after the hot deformation. Dynamic Recrystalization (DRX) could also explain the gentle oscillation in the appearance of the flow softening curves of the EBM samples. Moreover, the hot working analysis indicated that the activation energy for hot deformation of as-built EBM Tiā€“6Alā€“4V alloy was calculated as ~193.25 kJ/mol, which was much lower than the wrought alloy (229.34 kJ/mol). These findings can shed lights on a new integration of metal Additive Manufacturing (AM) and thermomechanical processing. It is very interesting to highlight that through this new integration, it would be possible to reduce the forging steps and save more energy and materials with respect to the conventional routes

    Pre-Hospital Trauma Care in Road Traffic Accidents in Kashan, Iran

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    Background: Iran has one of the highest rates of road traffic accidents (RTAs) worldwide. Pre-hospital trauma care can help minimize many instances of traffic-related mortality and morbidity. Objectives: The aim of this study was to assess the characteristics of pre-hospital care in patients who were injured in RTAs, admitted to hospital. The focus was mainly directed at evaluating pre-hospital trauma care provided in city streets and roads out of the city. Patients and Methods: This retrospective study was carried out on all trauma patients, transported by the emergency medical service (EMS) system, who were admitted to Kashan Shahid-Beheshti hospital during the period from March 2011 to March 2012. The patientsā€™ demographic data, location of accident, damaged organs, mechanism of injury, injury severity, pre-hospital times (response, scene, transport), pre-hospital interventions and outcomes, were extracted from the data registry and analyzed through descriptive statistics using SPSS 18 software. Results: Findings of this study showed that, 75% of RTAs occurred on city streets (n = 1 251). Motor-car accidents were the most frequent mechanism of RTA on city streets (n = 525) (42%), while car rollover was the most frequent mechanism of RTA on roads out of the city (n = 155) (44.4%). The mean pre-hospital time intervals (min); response, scene, and transport for all patients were 6.6 Ā± 3.1, 10.7 Ā± 5 and 13 Ā± 9.8, respectively. The mean pre-hospital time intervals (response, scene, transport) in roads out of the city were higher than those in city streets. There was a significant difference (P = 0.04) in the mortality rates due to RTAs between city streets (n = 46) and roads out of the city (n = 32). Conclusions: In comparison with road traffic accidents on city streets, trauma patients in RTAs on roads out of the city have longer pre-hospital time intervals and more severe injuries; therefore this group needs more pre-hospital resuscitation interventions

    Giant Strain and Induced Ferroelectricity in Amorphous BaTiO3 Films under Poling

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    We report an effect of giant surface modification of a 5.6 nm thick BaTiO3 film grown on Si (100) substrate under poling by conductive tip of a scanning probe microscope (SPM). The surface can be locally elevated by about 9 nm under āˆ’20 V applied during scanning, resulting in the maximum strain of 160%. The threshold voltage for the surface modification is about 12 V. The modified topography is stable enough with time and slowly decays after poling with the rate ~0.02 nm/min. Strong vertical piezoresponse after poling is observed, too. Combined measurements by SPM and piezoresponse force microscopy (PFM) prove that the poled material develops high ferroelectric polarization that cannot be switched back even under an oppositely oriented electric field. The topography modification is hypothesized to be due to a strong Joule heating and concomitant interface reaction between underlying Si and BaTiO3. The top layer is supposed to become ferroelectric as a result of local crystallization of amorphous BaTiO3. This work opens up new possibilities to form nanoscale ferroelectric structures useful for various applications
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