463 research outputs found

    Vibration of an initially stressed rectangular plate due to an accelerated traveling mass

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    AbstractThis paper presents a combined application of the Ritz method, the Differential Quadrature (DQ) method, and the Integral Quadrature (IQ) method to vibration problem of rectangular plates subjected to accelerated traveling masses. In this study, the Ritz method with beam eigenfunctions is first used to discretize the spatial partial derivatives with respect to a co-ordinate direction of the plate. The DQ and IQ methods are then employed to analogize the resultant system of partial differential equations. The resulting system of ordinary differential equations is then solved by using the Newmark time integration scheme. The mixed scheme combines the simplicity of the Ritz method and high accuracy and efficiency of the DQ method. The accuracy of the proposed method is demonstrated by comparing the calculated results with those of the existing literature. It is shown that highly accurate results can be obtained using a small number of Ritz terms and DQM sampling points. Finally, the effects of following parameters having something to do with the title problem are investigated: moving load speed and acceleration, and transverse inertia of the moving load. Numerical results show that all the above-mentioned parameters have significant effects on the transient response of such structures under traveling dynamic loads

    Results of open Bankart surgery for recurrent anterior shoulder dislocation with glenoid bone defect and concomitant Hill-Sachs lesion

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    Background: Open Bankart surgery is the main treatment procedure in patients with recurrent anterior shoulder dislocation, especially in cases with glenoid bone defect. The goal of this study was to determine the outcomes after open Bankart surgery in cases of recurrent anterior shoulder dislocation with glenoid bone defects and concomitant Hill-Sachs lesions. Methods: Between 2006 and 2010, 89 patients with recurrent anterior shoulder dislocation and concomitant glenoid bone defects (10-30) and Hill-Sachs lesions undergoing open Bankart surgery were reviewed. The mean followup after surgery was 7 years (5.5-9.5 years). The recurrence rate as well as the degree of shoulder pain and daily activity level was determined subjectively based on the visual analogue scale (VAS) and activity daily living scale (ADLs). Shoulder range of motion (ROM) in abduction and external rotation was compared with contralateral side; and finally, the American shoulder and elbow score (ASES) and constant-Murley score (CMS) were calculated. Results: Over 7 years of follow-up, a total of 15 patients (16.8) undergoing surgery were found to have instability (3 patients (3.3) with dislocation and 12 patients with (13.4) subluxation). Patients with postsurgical instability had significantly larger glenoid bone defects (P=0.0001) and Hill-Sachs lesions (P=0.019) compared to those without instability. The mean loss of forward flexion compared with the normal contralateral side was 4° while the mean loss of external rotation between both sides was 5°. At the final visit, the average VAS was 0.4 (out of 10); ADL was 28.97 (range: 25-30); ASES was 96.1(range: 78.3-100); and the mean CMS value was 93.9(range: 82-100). Conclusion: Open Bankart surgery with anteroinferior capsular shift for recurrent anterior shoulder dislocation with up to 30 glenoid bone defect and Hill-Sachs lesion provided desirable results in terms of shoulder function and recurrence rate. Bankart surgery is a successful and practical option in these patients and can be considered as an alternative to other procedures. © By The Archives of Bone and Joint Surgery

    Extraction-spectrophotometric determination of nickel at microgram level in water and wastewater using 2-[(2-mercaptophenylimino)methyl]phenol

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    An extraction-spectrophotometric method for determination of nickel at sub ppm level using 2-[(2-mercaptophenylimino)methyl]phenol (MPMP) as the new extractant is described. The reagent reacts with nickel(II) at pH > 10 and form a 1:2 brown complex, which is extracted into chloroform. The complex has a maximum absorption at 421 nm with the molar absorptivity of 2.41 × 105 M-1 cm-1. Beer’s law is obeyed over the range of 0.011-0.30 µg mL-1. The Sandell’s sensitivity for 0.001 absorbance unit is 5.34 × 10-4 µg cm-2. The relative standard deviation at 0.018 µg mL-1 is 1.1 % (n = 8). The procedure was successfully applied to determination of nickel in wastewater and standard alloy and the accuracy was determined by recovery experiment, independent analysis by furnace-AAS, and analysis of a certified reference martial. KEY WORDS: Ni determination, Liquid-liquid extraction, Schiff bases, Spectrophotometry Bull. Chem. Soc. Ethiop. 2008, 22(3), 323-329

    Changes in levels of cortisol, glucose and sex hormones during transportation of southern Caspian Kutum (Rutilus frisii kutum) spawners

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    Physiological changes in cortisol, glucose, testosterone and 17b-estradiol levels were studied in Rutilus frisii kutum spawners during transportation in April, 2006. The fish were held in plastic tanks in two treatments 1fish/2L and 1fish/1L sea water in several replications. Their blood was collected at 0, 10, 20, 30 and 60 min after capture. A significant increase in concentration of cortisol and glucose was found with the transport time. Initial levels of cortisol were similar in the two treatments ranging between 480.7±22.34 and 476.6±18.61 ng/ml respectively

    Retrograde intrarenal surgery versus shock wave lithotripsy for renal stones smaller than 2 cm: A randomized clinical trial

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    Purpose: To compare outcomes of retrograde intrarenal surgery (RIRS) with extracorporeal shock wave lithotripsy (SWL) for stones � 2 cm. Materials and Methods: Patients who were diagnosed with kidney stones of � 2 cm underwent RIRS or SWL in a parallel group randomized clinical trial with balanced randomization 1:1 from 2011 to 2014. The primary outcome of interest was stone free rate after a single session intervention. Patients were evaluated by ultrasonography and KUB at 1 and 3 months after the intervention for the presence of residual stone by a radiologist who was blinded to the study. Results: The stone free rate one month after a single session intervention in the RIRS group was higher than the SWL group (90% versus 75%, P = .03). The success rates after two sessions of RIRS versus SWL were 96.7% versus 88.3% respectively. (P = .08) Patients in the RIRS group had significantly lower postoperative visual analogue pain score compared to the SWL group (5.2 ± 2.8 versus 3.1 ± 2.7, P < .001). Steinstrasse formation and renal hematoma were observed in 4 and one patient in the SWL group versus no patient in the RIRS group. Postoperative hospital stay was significantly shorter in the SWL group (6.7 ± 1.3 versus18.9 ± 4.3 hours, P < .001). Conclusion: The RIRS procedure is a safe treatment option for renal stones of �2cm with less pain and higher success rate at first session compared to SWL

    Gonads tissue changes of Chalcalburnus mossulensis (Heckel, 1843) infected by Ligula intestinalis (Cestoda)

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    Chalcalburnus mossulensis from the cyprinidae family is one of the indigenous fish in Gheshlagh Lake of Kordestan, Iran. Ligula intestinalis is one of the infective parasites among various species of fish and causes gonads atrophy. In this study, after detection of species and age of samples, the effects of this parasite on gonads tissues and sexual maturation of Chalcalburnus mossulensis were investigated. By seasonal sampling 144 samples were collected. After investigatiing gonad tissue samples, it was clear that, there is a significant difference between the means of male and female gonads maturation rate in infected and non infected samples (p< 0.05). Infection by Ligula intestinalis can be the reason for lack of gonads maturation. In addition, the abnormal degenerative changes like, absorption follicle, hemorrhage and infiltration of inflammation cells in ovary tissues of infected fish were seen. In testicle tissue, dispersed hemorrhage, atrophy and MMC (melano-macrophage center) were seen as pathological signs. So the spread of this parasite in different water sources is important as the point the maintenance of native species and cultivated fish

    Results of open Bankart surgery for recurrent anterior shoulder dislocation with glenoid bone defect and concomitant Hill-Sachs lesion

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    Background: Open Bankart surgery is the main treatment procedure in patients with recurrent anterior shoulder dislocation, especially in cases with glenoid bone defect. The goal of this study was to determine the outcomes after open Bankart surgery in cases of recurrent anterior shoulder dislocation with glenoid bone defects and concomitant Hill-Sachs lesions. Methods: Between 2006 and 2010, 89 patients with recurrent anterior shoulder dislocation and concomitant glenoid bone defects (10-30) and Hill-Sachs lesions undergoing open Bankart surgery were reviewed. The mean followup after surgery was 7 years (5.5-9.5 years). The recurrence rate as well as the degree of shoulder pain and daily activity level was determined subjectively based on the visual analogue scale (VAS) and activity daily living scale (ADLs). Shoulder range of motion (ROM) in abduction and external rotation was compared with contralateral side; and finally, the American shoulder and elbow score (ASES) and constant-Murley score (CMS) were calculated. Results: Over 7 years of follow-up, a total of 15 patients (16.8) undergoing surgery were found to have instability (3 patients (3.3) with dislocation and 12 patients with (13.4) subluxation). Patients with postsurgical instability had significantly larger glenoid bone defects (P=0.0001) and Hill-Sachs lesions (P=0.019) compared to those without instability. The mean loss of forward flexion compared with the normal contralateral side was 4° while the mean loss of external rotation between both sides was 5°. At the final visit, the average VAS was 0.4 (out of 10); ADL was 28.97 (range: 25-30); ASES was 96.1(range: 78.3-100); and the mean CMS value was 93.9(range: 82-100). Conclusion: Open Bankart surgery with anteroinferior capsular shift for recurrent anterior shoulder dislocation with up to 30 glenoid bone defect and Hill-Sachs lesion provided desirable results in terms of shoulder function and recurrence rate. Bankart surgery is a successful and practical option in these patients and can be considered as an alternative to other procedures. © By The Archives of Bone and Joint Surgery

    Studies on seed and forage yield in 10 populations of sainfoin (Onobrychis saliva) grown as spaced plants and swards

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    In order to study seed and dry matter (DM) yield and relationships between yield and morphological traits, 10 populations of sainfoin (Onobrychis saliva), were assessed in two separate experiments under sward and spaced plant conditions using complete block design with two replications, in Karaj, Iran, during 2004-2007. The data were collected for seed yield, DM yield, plant height, stem number per m(2), flowering date, inflorescences length and 1000-grain weight. The data were analyzed for individual experiment and combined over two experiments. Results showed significant differences among populations for all of traits except 1000-grain weight in sward and DM yield and stem number in spaced plants. Results of combined analysis showed no significant differences among 2 conditions for both seed and DM yield. However, the average values of 7.3 and 6.2 ton ha(-1) DM yield and 337 and 375 kg ha(-1) seed yield were obtained for sward and spaced plants, respectively. Results showed that, populations of Shahrkord and Kashan with average values of 8.08 and 8.06 ton ha(-1) DM yield and Shahrkord with average values 551 kg ha(-1) seed yield had higher production under sward conditions. For spaced plants, Orumieh and Bijar with average values of 7.98 and 7.67 ton ha(-1) DM yield and Bijar and Esfahan with average values of 510 kg ha(-1) seed yield had higher production. Therefore, the populations of Shahrkord and Bijar were introduced as the best ones for both DM and seed production under swards and spaced plants, respectively. DM yield was positively correlated with seed yield, plant height, stem number and inflorescences length, while seed yield had positive and significant relationships with 1000-grain weight, plant height, stem number and inflorescences length. The relationship between spaced plants and swards as measured by phenotypic correlation was poor for all traits except 1000-grain weight. This suggests that response to selection based on spaced plant data would not be reflected in swards, so, for all characters selection should be based on sward yield

    Detection and identification of white spot syndrome virus (WSSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) of Litopenaus vannamei from Bushehr and Sistan and Baloochestan provinces (Iran), during 2009-2010

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    The first time the white spot disease (WSD) and IHHNV were reported in Iran was in 2004 and 2008, respectively in Bushehr Province. In Sistan and Balochestan province only the WSD was reported in 2008.The aim of this study was detecting these two viral diseases in these provinces, during December 2009 to April 2010. A total of 364 samples were collected according to suspected gross signs from hatcheries and shrimp farms in Bushehr and Sistan and Blochestan provinces (I.R. Iran) respectively, including larvae (72, 43 samples), post larvae (48, 37 samples), juveniles (57, 32 samples), sub adults (39, 22 samples) and broodstock (29, 13 samples) of Litopenaus vannamei . WSD was detected from juveniles (23 samples), sub adults (14 samples), and broodstock (14 samples), and IHHNV was also detected from juveniles (16 samples), sub adults (9 samples) and broodstock (5 samples) based on gross signs, PCR and histopathological changes from Bushehr province but from Sistan and Blochestan province only WSD was detected from juveniles (26 samples), sub adults (18 samples) and broodstock (7 samples). Histopathological observations of WSSV showed basophilic Cowdry type A inclusion bodies in all tissues such as gills, haematopoietic tissue, cuticle epithelium, lymphoid organ and connective tissue. However histologically, the hepatopancreas tissue showed vacuolization of B cells , without inclusion bodies, but histopatholgical changes caused IHHNV including eosinophilic Cowdry type A inclusion bodies which were ectodermal, mesodermal and rarely endodermal

    Exposure to nanoscale diesel exhaust particles: Oxidative stress, neuroinflammation, anxiety and depression on adult male mice

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    ABSTRACT Exposure to nanoscale diesel engines exhausted particles (DEPs) is a well-recognized risk factor for respiratory and cardiovascular diseases. Rodents as commonly used models for urban air pollution in health effect studies demonstrate constant stimulation of inflammatory responses in the main areas of the brain. Nevertheless, the primary effect of diesel exhaust particulate matter on some of the brain regions and relation by behavioral alterations still remains untouched. We evaluated the brain regional in flammatory responses to a nanosized subfraction of diesel engines exhaust particulate matter (DEPs < 200 nm) in an adult male mice brain. Adult male mice were exposed to DEPs for 3, 6, and 8 h per day, 12 weeks and five days per week. Degree of anxiety and the depression by elevated plus maze and Forced Swimming Test respectively (FST) did measurement. After behavior tests, the plasma and some of the brain regions such as olfactory bulb (OB) and hippocampus (HI) were analyzed for oxidative stress and in flammatory responses. The inflammation and oxidative stress changes in OB and HI, markedly coincides with the results of behavioral alterations. These responses corresponded with rapid induction of MDA and nitrite oxide (NO) in brain regions and neuronal nitric oxide synthase (nNOS) mRNA followed by IL6, IL1 α , and TNF α in OB and HI. The different times of DEPs exposure, leads to oxidative stress and inflammatory in plasma and brain regions. That this cumulative transport of inhaled nanoscale DEPs into the brain and creating to inflammation responses of brain regions may cause problems of brain function and anxiety and depression. Keywords: Air pollution Nanoscale diesel exhaust particles Oxidative stress Nanotoxicology Anxiety Depressio
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