41 research outputs found
Automatic Hotspots Detection for Intracellular Calcium Analysis in Fluorescence Microscopic Videos
Get PDFIn recent years, life-cell imaging techniques and their software applications have become powerful tools to investigate complex biological mechanisms such as calcium signalling. In this paper, we propose an automated framework to detect areas inside cells that show changes in their calcium concentration i.e. the regions of interests or hotspots, based on videos taken after loading living mouse cardiomyocytes with fluorescent calcium reporter dyes. The proposed system allows an objective and efficient analysis through the following four key stages: (1) Pre-processing to enhance video quality, (2) First level segmentation to detect candidate hotspots based on adaptive thresholding on the frame level, (3) Second-level segmentation to fuse and identify the best hotspots from the entire video by proposing the concept of calcium fluorescence hit-ratio, and (4) Extraction of the changes of calcium fluorescence over time per hotspot. From the extracted signals, different measurements are calculated such as maximum peak amplitude, area under the curve, peak frequency, and inter-spike interval of calcium changes. The system was tested using calcium imaging data collected from Heart muscle cells. The paper argues that the automated proposal offers biologists a tool to speed up the processing time and mitigate the consequences of inter-intra observer variability
ESTIMATION OF COEFFICIENTS OF WILLIAMS' SERIES IN LEFM PROBLEMS USING DECOUPLED EQUATIONS METHOD
No full textThe existence of crack and notch is a significant and critical subject in the analysis and design of solids and structures. As most of cracked domain problems do not have closed-form solutions, numerical methods are the current approaches dealing with fracture mechanics problems. This study presents a novel application of the decoupled equations method (DEM) to model crack issues. Based on linear elastic fracture mechanics (LEFM), the first four coefficients of the Williams' series for the crack tip's asymptotic elastic field are computed using the DEM. In this method, only the boundaries of problems are discretized using specific higher-order sub-parametric elements and higher-order Chebyshev mapping functions. Implementing the weighted residual method and using Clenshaw-Curtis quadrature result in diagonal Euler's differential equations. In the present method, the so-called local coordinate's origin (LCO) is selected at a point, from which the entire domain boundary may be observed. For the bounded domains, the LCO may be chosen on the boundary or inside the domain. Furthermore, only the boundaries which are visible from the LCO need to be discretized, while other remaining boundaries passing through the LCO are not required to be discretized. Consequently, when the local coordinates origin (LCO) is located at the crack tip, the geometry of crack problems is directly implemented without further processing. In fracture mechanics problems, the stress at the crack tip approaches to infinity, and hence the original DEM is not able to represent infinite stress at the crack tip, basically. To overcome this problem, a new form of force function is constructed to represent infinite stress at the crack tip, and the first four coefficients of the Williams' series are then computed. Validity and accuracy of this method is fully demonstrated through two benchmark problems. The results show that stress and displacement fields agree very well with the results of other methods. In addition, the coefficients of the Williams' series show good agreement with the results of existing methods available in the literature
Mechansim and outcome of hip fracture: a multi-center study
No full textBackground: 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
Optogalvanic spectroscopy with microplasma sources—current status and development towards a lab on a chip
No full textThe Use of head CT scanning in mild head injury
No full textObjectives: To determine the number of brain CT scans carried out in patients with mild head injury (MHI) during 13 months of trauma registry, and to investigate means of reducing the rate of unnecessary scans. Methods: During a trauma registry (from August 23, 1999 to September 21, 2000) in 6 general Hospitals (Imam Hussein, Moayer, Sina, Hafteteer, Imam Khomeini and Shariatti) in Tehran, Iran, 1209 cases with Glasgow Coma Scale (GCS) score >13 underwent brain CT scan. To be included in the study, patients must have sustained their injury within one week prior to presentation to Emergency Rooms, and were hospitalized for more than 24 hours. The attending physicians formally reported all brain CT scan findings. Results: For 1209 patients, there were the following characteristics: mean age was 29.4 years; the main cause of injury was traffic accidents (60.1%), followed by falls (28.5%), fights (7.2%), and other reasons (4.2%). Seventyseven cases (6.4%) had a GCS score of 13, 212 (17.5%) had a score of 14, and 920 (76%) had a score of 15. A total of 481 abnormalities on CT scan were reported for 405 patients (33.5%) with positive report of brain CT scan, while 804 cases (66.5%) did not report abnormalities. The most common intracranial lesion was epidural hemorrhage with 146 cases (30.3%). The rate of negative reporting of brain CT scan in patients who had GCS score of 15 was 72.2%. Conclusion: Patients who have GCS score of 13 or 14 on admission should be considered to have a moderate rather than a mild head injury. For reduction of unnecessary brain CT scan performance in MHI patients, we must define the appropriate criteria.4 page(s
Helicopter emergency medical system in a region lacking trauma coordination (experience from Tehran)
No full textBackground: The helicopter emergency medical service (HEMS) has been working in Iran since 2000. The present study is the first prospective research to determine the epidemiological characteristics of injured patients transported by helicopter in Tehran. Methods: All injured patients brought to three hospitals from the injury scene by HEMS were reviewed in a 4-month period. Results: The mean transport time was 54 minutes. The most common mechanism of trauma was road traffic accidents (96.2%). The mean injury severity score was 8.6 (SD 8.6) and 9.6% of patients were sent to the intensive care unit; 10.2% of patients died. Conclusion: This study shows that overtriage in HEMS (transportation of patients without severe injuries) and the long transportation time is mainly a result of not having a trauma system. The study has shown HEMS to be an effective and feasible option in countries with heavy traffic and no trauma system
Microstructural features and mechanical properties of spray -formed hypereutectic Al-Si-Ti alloy
No full textIn the present study, the effect of the addition of Ti on the microstructural and mechanical properties of hypereutectic (Al/15 wt. %Si) spray-formed (SF) alloys has been investigated and compared with as-cast (AC) alloys. Al/15Si and Al/15Si/2Ti alloys were synthesised by spray forming method. The microstructural features of the alloys were explored under an optical microscope, and a scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis were carried out for phase identification. The phase analysis confirmed the presence of α-Al and Si phases in all the alloys, with additional peaks attributed to Al3Ti and AlSi2Ti present in the Al/15Si/2Ti alloys. The microstructure of the SF1 alloy (Al/15Si) consisted of globular, fine Si phases (primary and eutectic) distributed homogeneously in the equiaxed Al matrix. The addition of Ti to the binary SF1 alloy led to the formation of an SF2 alloy (Al/15Si/2Ti) with a fine intermetallic phase of Al3Ti and further spheroidisation of Si particles. The SF1 and SF2 alloys exhibited 30% and 40% greater microhardness, respectively, than did their corresponding AC alloys. With the addition of Ti, the ultimate tensile strength of the SF2 alloy increased by 19% compared to that of the SF1 alloy. Furthermore, a significant increase in yield strength and ductility was observed in the SF alloys compared to the AC alloys. Adding Ti to hypereutectic Al/15Si alloy via the spray-forming method provides a better alternative material for aerospace and automotive applications
EPIDEMIOLOGICAL STUDY OF PATIENTS WITH PENETRATING ABDOMINAL TRAUMA IN TEHRAN-IRAN
No full textTrauma continues to be the most frequent cause of death in the first four decades of life that is a main public health problem in some countries. We perform an epidemiological study of Penetrating Abdominal Trauma (PAT). We describe epidemiological of patients in PAT. In a cross-sectional study we evaluated epidemiological PAT admitted to emergency department in six general hospitals in Tehran. The data was collected through a questionnaire that was completed by trained physician trauma center. Statistical analysis was performed using the SPSS software (version 11.5 for windows). Statistical analysis using the chi-square and P<0.05 was accepted as being statistically significant. During the study period, 0.86 % (69/8000) of our patients sustained PAT. Sixty-six (95.7%) patients were male and 3(4.3%) cases were female. The peak age incidence was 15-29 years, with 43(62.3%) patients. Stab wound was the leading cause of PAT in male and female, with 62(89.9%) cases. Firearm was responsible for 7(10.1%) cases. Young males are the most common victims. This is the most productive age group and this has grave implication for the national economy
Epidemiology of outpatient burns in Tehran: An analysis of 4813 cases
No full textThis study aims to demonstrate the epidemiologic characteristics of outpatient burn injuries in Tehran. This cross-sectional study was performed over a 1-year period in a referral burn centre in Tehran and included all outpatient burns. The required data were recorded by two trained physicians. Of the 4813 studied patients, including 293 infants, 2901 patients (60) were male (P < 0.001). The mean age of the adult patients was 31.3 ± 18.3 years, while for infants it was 10.68 ± 2.27 months. In all age groups and both genders, scalding was the most common aetiology. Majority of the burns were non-intentianal (n = 4808) and 70.5 of the injuries occurred at home. Housewives consisted of 24 of the burn patients. With respect to the site of burn, multiple injuries were the most frequent (53) followed by upper extremities (37). Most of the burns (96) were partial thickness. Significant association was present between the aetiology and depth of burn (P < 0.001). The mean affected total body surface area (TBSA) was 3.16 ± 2.92 and there was significant association between burnt TBSA and the mechanism of injury (P < 0.001). In conclusion, it seems that women aged 21-30 years and children younger than 10 years are at greater risk of these injuries and therefore should be the target for preventive strategies. © 2009 Elsevier Ltd and ISBI
Women Pose Innocent Victims of Landmines in Postwar Iran
No full text"nBackground: Although in the last few years there has been an increasing attention to the problem of landmines, to date, the implications of women being victims of landmine has not been duly dealt with in the world including Iran, which is estimated to be the second most landmine infested country in the world. Still, provinces by the west border of Iran, 18 years after cessation of Iraq-Iran war suffer from the burden of vast areas, highly infested with landmines. This study aimed to provide a gender focused insight into landmine accidents in Iran."nMethods: In this retrospective study, women with documented deaths or injuries due to landmine and/or unexploded ordnances (UXO) explosions as documented in their medical records between Jul 1988 (after ceasefire) and Feb 2003 were studied in 5 western provinces of Iran. Data was analyzed by SPSS for Windows Version 11.P value under 0.05 was consid&shy;ered statistically significant."nResults: During the 14-year study period, 252 women from 5 western provinces of Iran were reported to have injuries or death due to landmine and UXOs. All of the victims were civilians and the majority of them (47.6%) had one or more amputations. Most of them were injured in the period between1994 and 1998. The majority of the patients were young."nConclusion: Women who should take care of themselves as well as their families are more prone to sufferings inflicted by landmines and UXO
