71 research outputs found
Significance of bedrock depth in dynamic soil-structure interaction analysis for moment resisting frames
In this study, a fifteen storey moment resisting building frame, resting on a shallow foundation, is selected in conjunction with two clayey soils with the shear wave velocities less than 600m/s, representing soil classes De and Ee, according to AS 1170.4. Different bedrock depths including 10m, 20m, and 30 m are employed in the numerical modelling using finite difference software FLAC 2D. Fully nonlinear dynamic analysis under the influence of different earthquake records is conducted, and the results of the three different cases are compared and discussed. The results indicate that the dynamic properties of the subsoil such as shear wave velocity as well as bedrock depth play significant roles in seismic response of the building frames under the influence of soil-structure interaction. As the bedrock depth increases, lateral deflections and inter-storey drifts of the structures increase. These effects can change the performance level of structures from life safe to near collapse or total collapse. Therefore, the conventional design procedure excluding SSI is not adequate enough to guarantee the structural safety for the building frames resting on soft soil deposits
Effects of soil-pile-structure interaction on seismic response of moment resisting buildings on soft soil
Dynamic response of structures sitting on soft soils is influenced by the soil properties, and the response is significantly different to the fixed base condition owing to the interaction between the ground and the structure, In order to study this effect, a fifteen storey moment resisting building frame, representing a conventional type of regular mid-rise building frame, resting ,on soil type Ee according to Australian Earthquake action code with the shear wave velocity equal to 150 mls is adopted. The numerical analysis using FLAC2D software is carried out for three different cases, namely: (1) fixed-base structure representing the situation excluding the soil-structure interaction (SSI); (2) structure supported by shallow foundation on soft soil; and (3) structure supported by pile foundation in soft soil. Benchmark earthquakes including the 1995 Kobe, the 1994 Northridge, the 1968 Hachinohe, and the 1940 EI Centro earthquakes are adopted. Results indicate that considering soil-structure interaction in both cases with shallow and pile fouudations is vital, and the conventional desigu procedure excluding soil-structure interaction is not adequate to guarantee the structural safety for the moment resisting buildings resting on the soft soil
Effect of different Concentrations of Salicylic acid on some Physicochemical Properties of Grape cv. Shahroodi
Introduction Grape (Vitis vinifera L.) is one of the most important fruits cultivated in many areas with different climates all over the world. Grape, which is rich in antioxidants, flavonoids, anthocyanins and phenolic acids, is highly regarded in terms of economic value. Salicylic acid is one of the compounds which have been used in recent years for improving the physicochemical properties of many fruits. The application of salicylic acid increases the shelf life of crops by inhibiting ethylene production and respiration, as well as by reducing the activity of some enzymes which are responsible for softening the cell wall. Furthermore, salicylic acid results in the enhancement of phenolic compound production by increasing the activity of some enzymes such as phenylalanine ammonia-lyase.Materials and Methods The present study was conducted in 2014 on 13-year-old Shahroodi grapes that were grown using a head-training system with a spacing of 2m × 2m in "Shahrood" County, Semnan Province. A total of 60 grapevines with uniform age and growth characteristics were selected for the experiment. Salicylic acid was obtained from Merck and solutions were prepared using a small amount of organic solvent and surfactant to reduce the surface tension of the solutions. For the purpose, the Salicylic acid powder was dissolved in a few drops of ethanol and a few drops of Tween 20 for improving solution penetration to the plants, The solution was prepared at concentrations of 0 (control), 1, 2, 3 mM. Then the plants were sprayed two weeks after the fruit set stage (when berries were at the pea-sized stage with a diameter of 4 to 5 mm). The experimental design used in this experiment was a randomized complete block design (RCBD) with three replications. After harvesting and transporting of fruits to the laboratory, different characteristics were measured:Chlorophyll and carotenoid ContentChlorophyll a, b, and total Chlorophyll and carotenoid content measured according to Arnon (1967) method in grape leaves. The extraction steps were carried out with full precision to minimize contact with heat and light. In order to stabilize the pigments, the samples taken from the central part of the mature leaves were immediately ground in liquid nitrogen. The samples were vortexed two times with an interval of one minute and stored for 1.5 hours at a temperature of 4 degrees Celsius in order to dissolve the pigments in cold acetone solvent. After that, they were centrifuged for 15 minutes at a speed of 6000 rpm. The supernatant after centrifugation of the samples was used to measure chlorophyll and total carotenoids. The absorbance of the samples was read at three wavelengths of 470, 645, and 663 nm using a Shimadzu UV (160) spectrophotometer. Using the absorbance of the samples in these three wavelengths and the equations below, the amounts of chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids were calculated in terms of milligrams per gram of tissue sample weight.Fruit characteristics Fruit characteristics such as fruit yield, fruit firmness (with magnets-Taylor device), sugar and acid content, and content of phenolic compounds were also measured. The fruit tissue firmness was measured using a firmness tester (model FDKA 32, Wagner) and expressed in Newtons per square centimeter. The characteristics of soluble solids (TSS) were expressed using a handheld refractometer (Ataga, Japan) and expressed in terms of Brix, the pH of the extract was measured using a digital pH meter (Sartorius PP-20, Germany). Titratable acidity or TA was done through the titration of the extract using 0.1 normal sodium until pH 1.8-2.8 and its results were reported using the following formula and under the title of tartaric acid percentage.Total phenol content The amount of total phenol was measured by Folin-Ciocalteu method and spectrophotometry. The absorbance of the reaction mixture was measured after 120 minutes of storage in the absence of light at a wavelength of 765 nm using a Shimadzu UV spectrophotometer (160). The amount of total phenol was expressed from the standard curve in terms of mg of gallic acid per 100 grams of extract in three replicates for each sample and standard.Total flavonoid The amount of total flavonoid was measured by aluminum chloride calorimetric method. In this experiment, 50 microliters of methanolic extract from the flesh and fruit skin were combined with 10 microliters of 10% aluminum chloride and 10 microliters of 1 M potassium acetate. Then, 280 microliters of double distilled water were added to the mixture. After the samples were mixed, they were left at room temperature for 40 minutes. The absorbance of the reaction mixture was measured at a wavelength of 415 nm using a Shimadzu UV spectrophotometer (160) in three replicates. A blank containing double distilled water was used for comparison. The amount of total flavonoids was determined based on the standard curve of quercetin and the results were expressed in micrograms of quercetin per gram of fruit skin and flesh weight.Total anthocyanin The amount of total anthocyanin was measured using the difference in pH method. In this method, the absorbance was measured using a spectrophotometer at wavelengths of 520 and 700 nm along with potassium chloride and sodium acetate buffers with different pH values of 1 and 4.5.Results The results of the data analysis of variance showed that the application of salicylic acid resulted in significant differences in the measured characteristics. Therefore, the use of this compound improved the physical and biochemical quality of the treated grape clusters.Comparison of treatments means showed that using 2 mM salicylic acid brought about a significant effect on the amount of chlorophyll (a, b and total) and carotenoids compared to other treatments, especially control. Salicylic acid application caused a reduction in pH and soluble solids, and an increase in firmness, 100-berry weight and yield. The results of the study indicated a significant increase in organic acids and a decrease in reducing sugars in the grape clusters treated with salicylic acid. The highest amount of tartaric acid was found in the treatment with 2 mM salicylic acid, with an average of 0.66, while the control treatment had the lowest amount of tartaric acid, with an average of 0.52. This suggests that the use of salicylic acid led to a reduction in transpiration and consumption of organic acids. In terms of reducing sugars, the highest and lowest amounts were observed in the control treatment (14%/74) and the treatment with 2 mM salicylic acid (13%/60), respectively. Increasing the concentration of salicylic acid up to 2 mM resulted in the enhancement of anthocyanins and phenolic compounds contents, but higher concentrations (more than 2 mM) reduced the amounts of these compounds in treated fruits.Conclusion Pre-harvest use of salicylic acid could have a positive effect on the improvement of qualitative and quantitative characteristics of grape cv. Shahroodi. However, further comprehensive studies are needed to be conducted to recommend this compound to the growers of fruit trees
Decompressive surgery in cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia
Background and purpose: Cerebral venous sinus thrombosis due to vaccine-induced im-mune thrombotic thrombocytopenia (CVST-VITT) is an adverse drug reaction occurring after severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) vaccination. CVST-VITT patients often present with large intracerebral haemorrhages and a high proportion undergoes decompressive surgery. Clinical characteristics, therapeutic management and outcomes of CVST-VITT patients who underwent decompressive surgery are described and predictors of in- hospital mortality in these patients are explored.Methods: Data from an ongoing international registry of patients who developed CVST within 28 days of SARS-CoV- 2 vaccination, reported between 29 March 2021 and 10 May 2022, were used. Definite, probable and possible VITT cases, as defined by Pavord et al. (N Engl J Med 2021; 385: 1680–1689), were included. Results: Decompressive surgery was performed in 34/128 (27%) patients with CVST- VITT. In- hospital mortality was 22/34 (65%) in the surgical and 27/94 (29%) in the non- surgical group (p< 0.001). In all surgical cases, the cause of death was brain herniation. The highest mortality rates were found amongst patients with preoperative coma (17/18, 94% vs. 4/14, 29% in the non-comatose; p< 0.001) and bilaterally absent pupillary re-flexes (7/7, 100% vs. 6/9, 67% with unilaterally reactive pupil, and 4/11, 36% with bi-laterally reactive pupils; p= 0.023). Postoperative imaging revealed worsening of index haemorrhagic lesion in 19 (70%) patients and new haemorrhagic lesions in 16 (59%) pa-tients. At a median follow-up of 6 months, 8/10 of surgical CVST-VITT who survived ad-mission were functionally independent.Conclusions: Almost two-thirds of surgical CVST-VITT patients died during hospital ad-mission. Preoperative coma and bilateral absence of pupillary responses were associated with higher mortality rates. Survivors often achieved functional independence.Peer reviewe
Global Impact of the COVID-19 Pandemic on Cerebral Venous Thrombosis and Mortality
Background and purpose: Recent studies suggested an increased incidence of cerebral venous thrombosis (CVT) during the coronavirus disease 2019 (COVID-19) pandemic. We evaluated the volume of CVT hospitalization and in-hospital mortality during the 1st year of the COVID-19 pandemic compared to the preceding year.
Methods: We conducted a cross-sectional retrospective study of 171 stroke centers from 49 countries. We recorded COVID-19 admission volumes, CVT hospitalization, and CVT in-hospital mortality from January 1, 2019, to May 31, 2021. CVT diagnoses were identified by International Classification of Disease-10 (ICD-10) codes or stroke databases. We additionally sought to compare the same metrics in the first 5 months of 2021 compared to the corresponding months in 2019 and 2020 (ClinicalTrials.gov Identifier: NCT04934020).
Results: There were 2,313 CVT admissions across the 1-year pre-pandemic (2019) and pandemic year (2020); no differences in CVT volume or CVT mortality were observed. During the first 5 months of 2021, there was an increase in CVT volumes compared to 2019 (27.5%; 95% confidence interval [CI], 24.2 to 32.0; P<0.0001) and 2020 (41.4%; 95% CI, 37.0 to 46.0; P<0.0001). A COVID-19 diagnosis was present in 7.6% (132/1,738) of CVT hospitalizations. CVT was present in 0.04% (103/292,080) of COVID-19 hospitalizations. During the first pandemic year, CVT mortality was higher in patients who were COVID positive compared to COVID negative patients (8/53 [15.0%] vs. 41/910 [4.5%], P=0.004). There was an increase in CVT mortality during the first 5 months of pandemic years 2020 and 2021 compared to the first 5 months of the pre-pandemic year 2019 (2019 vs. 2020: 2.26% vs. 4.74%, P=0.05; 2019 vs. 2021: 2.26% vs. 4.99%, P=0.03). In the first 5 months of 2021, there were 26 cases of vaccine-induced immune thrombotic thrombocytopenia (VITT), resulting in six deaths.
Conclusions: During the 1st year of the COVID-19 pandemic, CVT hospitalization volume and CVT in-hospital mortality did not change compared to the prior year. COVID-19 diagnosis was associated with higher CVT in-hospital mortality. During the first 5 months of 2021, there was an increase in CVT hospitalization volume and increase in CVT-related mortality, partially attributable to VITT
Global Impact of the COVID-19 Pandemic on Cerebral Venous Thrombosis and Mortality.
BACKGROUND AND PURPOSE: Recent studies suggested an increased incidence of cerebral venous thrombosis (CVT) during the coronavirus disease 2019 (COVID-19) pandemic. We evaluated the volume of CVT hospitalization and in-hospital mortality during the 1st year of the COVID-19 pandemic compared to the preceding year. METHODS: We conducted a cross-sectional retrospective study of 171 stroke centers from 49 countries. We recorded COVID-19 admission volumes, CVT hospitalization, and CVT in-hospital mortality from January 1, 2019, to May 31, 2021. CVT diagnoses were identified by International Classification of Disease-10 (ICD-10) codes or stroke databases. We additionally sought to compare the same metrics in the first 5 months of 2021 compared to the corresponding months in 2019 and 2020 (ClinicalTrials.gov Identifier: NCT04934020). RESULTS: There were 2,313 CVT admissions across the 1-year pre-pandemic (2019) and pandemic year (2020); no differences in CVT volume or CVT mortality were observed. During the first 5 months of 2021, there was an increase in CVT volumes compared to 2019 (27.5%; 95% confidence interval [CI], 24.2 to 32.0; P<0.0001) and 2020 (41.4%; 95% CI, 37.0 to 46.0; P<0.0001). A COVID-19 diagnosis was present in 7.6% (132/1,738) of CVT hospitalizations. CVT was present in 0.04% (103/292,080) of COVID-19 hospitalizations. During the first pandemic year, CVT mortality was higher in patients who were COVID positive compared to COVID negative patients (8/53 [15.0%] vs. 41/910 [4.5%], P=0.004). There was an increase in CVT mortality during the first 5 months of pandemic years 2020 and 2021 compared to the first 5 months of the pre-pandemic year 2019 (2019 vs. 2020: 2.26% vs. 4.74%, P=0.05; 2019 vs. 2021: 2.26% vs. 4.99%, P=0.03). In the first 5 months of 2021, there were 26 cases of vaccine-induced immune thrombotic thrombocytopenia (VITT), resulting in six deaths. CONCLUSIONS: During the 1st year of the COVID-19 pandemic, CVT hospitalization volume and CVT in-hospital mortality did not change compared to the prior year. COVID-19 diagnosis was associated with higher CVT in-hospital mortality. During the first 5 months of 2021, there was an increase in CVT hospitalization volume and increase in CVT-related mortality, partially attributable to VITT
The Status of Road Safety in Iran during 2001 – 2006
Introduction: In developing countries, promotion of road safety is of crucial importance. This paper presents the status of road safety in Iran during 2001 - 2006. .
Material and Method: The status of road safety in Iran was surveyed in this descriptive study using road safety indicators a in macro level. Firstly, 46 indicators were identified after studying almost all indicators related to the road safety. After consulting of views with road safety experts and considering the reliable existing data, 11 indicators were selected to study the safety status of the roads. Then, all essential data for determining each indicators were collected from related organizations and institutes. All indicators were determined and evaluated in the last step.
.Result: The results revealed that during the period of 6 years, death toll has been increased by 9 deaths per 100000 person of the population. Moreover, application of seat belt and safety helmet has been increased by 20% and 18%, respectively. It also indicated that the number of motorists and the length of paved roads have been increased by 20%, and 10%, respectively. The net income per capita has also grown from 5884 US and the life expectancy has gone up from 68.9 years to 70.9 years, the percentage of the literate population has grown by 2% (from 76% to 78%) and the human development index has increased from 0.721 to 0.759. The results of the present study showed that the increased level of death toll per 10000 vehicles and the increased level (%) of seat belt as well as helmet application, paved roads, urbanization, the net income per capita, life expectancy, literacy and human development index were statistically significant and R2 coefficient for this factors was 0.84, 0.9, 0.994, 0.9, 0.97, 0.82, 0.69 and 0.84 respectively.
.Conclusion: According to result of the present study, roads safety were not in an appropriate level. The roads safety status can be determined using road safety indicators to be applied for road safety promotion
Evaluation on Some Treatments After Spring Frost Damage in Inflorescence Bud Formation in Pistachio Orchard
Abstract: (In the 3rd of April 2008) and in the morning of (16 April 2008), the temperature reached -6 ο C in some pistachio gardens of Kerman County especially in Sirjan. The coldness was so high that affected not only on the open flowers but also on bud endings and lop growth, So that the next year product was endangered, as well. In order to study the effect of some treatments and decrease the damage, some experiments were done in the form of split. Split was tested in the form of random block model so that original plot included irrigation treatments and nitrogen fertilizer was on 30 days after the cold happening , and secondary plot included prune treatments : in three levels, 1. Without prune, 2. Elimination of 30% of grown branches, 3. Elimination of 60% of grown branches. Allendance with pbz in three levels: 1. control, 2. 4 PPM Pbz, 3. 8 PPM Pbz with density. For every treatment, four repetitions were done, and the percentage of bud formation was measured. Results showed that although the irrigation after happening of coldness has stimulated the growth but it wasn't any influence on the next year product. Also it was defined that the mutual effect between irrigation and nitrogen fertilizer increased the formation of bud. The combination of irrigation, nitrogen fertilizer and 30% treatment caused the maximum of flower formation, and pbz increased the flower formation as well. According to results, it is said that 30% treatment could improve the problems of coldness
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