3036 research outputs found
Sort by
Assessment of uncertainties in damping reduction factors using ANN for acceleration velocity and displacement spectra
No full textElastic analysis is performed during the design process, and earthquake forces are computed according to standard damped spectral accelerations, which are assumed to be 5% at most. However, buildings are expected to behave nonlinearly instead of linearly due to moderate to destructive earthquakes. Accordingly, the damping factor between the design and actual behaviour of buildings during earthquake excitation differs. This situation increases the uncertainty of the design process for structures exposed to seismic loads and the variation in the reliable estimation of the structures' seismic response. This study is focused on the investigation of the structural damping uncertainties effect on the structure's response spectra through the assessment of uncertainties in the damping reduction factors (DRF) derived from the acceleration, velocity, and displacement spectra. For this purpose, the Monte Carlo method, which relies on repeated random sampling to obtain numerical results, is used for the estimation of the stochastic DRF. The obtained results indicate that the difference between the deterministic and stochastic DRF is around 21% for displacement and velocity and 28.7% for acceleration spectra. Consequently, the DRF derived from the acceleration spectra is more sensitive to the uncertainties inherent in damping than the DRF obtained from displacement and velocity. Therefore, it is important to take this conclusion into account when using these factors. To estimate the calculated DRF values, an artificial neural network (ANN) was developed for the stochastic DRF calculation. The ANN constitutes a simple and efficient method to predict the stochastic DRF since the error obtained is always less than 6%. According to the developed model, practice-oriented results are evaluated for the future evolution of seismic codes
Molecular docking and dynamics simulation coupled with MM-GBSA calculations
No full textAdenosine deaminase (ADA) is a Zn2+-containing enzyme that catalyzes the irreversible deamination of adenosine to inosine or deoxyadenosine to deoxyinosine. In addition to this enzymatic function, ADA mediates cell-to-cell interactions involved in lymphocyte co-stimulation or endothelial activation. ADA is implicated in cardiovascular pathologies such as atherosclerosis and certain types of cancers, including lymphoma and leukemia. To date, only two drugs (pentostatin and cladribine) have been approved for the treatment of hairy cell leukemia. In search of natural ADA inhibitors, we demonstrated the binding of selected phenolic compounds to the active site of ADA using molecular docking and molecular dynamics simulation. Our results show that phenolic compounds (chlorogenic acid, quercetin, and hyperoside) stabilized the ADA complex by forming persistent interactions with the catalytically essential Zn2+ ion. Furthermore, MM-GBSA ligand binding affinity calculations revealed that hyperoside had a comparable binding energy score (& UDelta;G = - 46.56 & PLUSMN; 8.26 kcal/mol) to that of the cocrystal ligand in the ADA crystal structure (PDB ID: 1O5R) (& UDelta;G = - 51.97 & PLUSMN; 4.70 kcal/mol). Similarly, chlorogenic acid exhibited a binding energy score (& UDelta;G = - 18.76 & PLUSMN; 4.60 kcal/mol) comparable to those of the two approved ADA inhibitor drugs pentostatin (& UDelta;G = - 14.54 & PLUSMN; 2.25 kcal/mol) and cladribine (& UDelta;G = - 25.52 & PLUSMN; 4.10 kcal/mol) while quercetin was found to have modest binding affinity (& UDelta;G = - 8.85 & PLUSMN; 7.32 kcal/mol). This study provides insights into the possible inhibitory potential of these phenolic compounds against ADA
Frequency of internet addiction and impact on the musculoskeletal system in high school students
No full textIt is known that increasing internet use increases internet addiction levels in adolescents and this leads to many health problems, especially musculoskeletal pain. The purpose of this study was to investigate the prevalence of internet addiction in high school students as well as the impact on the musculoskeletal system. This cross-sectional study included 986 high school students from Diyarbakir, Turkey. The students were assessed using the Socio-demographic Information Form, Young Internet Addiction Scale, Nordic Musculoskeletal System Questionnaire, Visual Analog Scale, and Online Questionnaire method. It was found that 26.2% of the students are addicted to the internet. While neck pain was the leading musculoskeletal system problem of the students in the last 12 months with 61.3%, the low back was the region that had the most impact on adolescents ability to go about their daily lives with 31.2%. The internet addicts' musculoskeletal discomfort in the previous year in all body parts and pain in the last 7 days in all body parts except the elbows were statistically significantly higher than the non-addicted group (p<0.05). The prevalence of internet addiction among students has been found to be significant, and this addiction causes musculoskeletal pain and activity limitations in many body parts
The Effect of Vitamin D Level on the Clinical Situation in COVID-19 Patients
No full textObjective: Vitamin D plays an important role in maintaining the integrity of mucosal barriers and in natural and acquired immunity. In the COVID-19 pandemic, the strength of personal immunity is very important in the course of the disease, despite the presence of variants of the virus or vaccination status. Method: In this study, we investigated the relationship between the clinical course and vitamin D levels of outpatient and inpatient follow-up patients admitted to our hospital due to COVID-19. A total of 94 patients, 47 outpatients and 47 inpatients, were included in the study. Results: The mean age and gender distributions of both groups were similar. Vitamin D levels were found to be normal in only 7 of 94 patients who were followed up in our hospital due to COVID-19. Patients with vitamin D levels >= 30 were significantly lower than those with "= 30. Additionally, the outpatients (29%) with vitamin D levels = 30. Conclusion: The data showed that vitamin D deficiency may be associated with the severe clinical course of COVID-19, even in patients without comorbidities, and may also be one of the predisposing factors resulting in death in COVID-19. As a result, vitamin D levels in COVID-19 patients may be important for the course of the disease
Monitoring of antibody levels in healthcare workers after inactivated coronavirus disease 19 vaccination
No full textOBJECTIVE: Because of the coronavirus disease 19 pandemic, studies on vaccination are being conducted in our country as well as across the world. In this study, the antibody levels in healthcare workers vaccinated with two doses of inactivated vaccine and the factors affecting these levels were investigated. METHODS: Randomly selected volunteers from healthcare workers, who had been vaccinated with two doses of inactivated vaccine in January to February 2021, were included in the study. Blood samples were drawn twice, 1 month and 6 months after the second dose vaccine (CoronaVac:Sinovac Life Science Co, Ltd, Beijing, China). The antibody levels were determined by the chemiluminescence microparticle immunoassay method using kits for quantitative detection of immunoglobulin class G antibodies to severe acute respiratory syndrome coronavirus 2. RESULTS: The mean antibody levels of 129 volunteers were 1232.5 (min: 103 to max: 7151) AU/mL in the first month and 403.5 (min: 23 to max: 4963) AU/mL in the sixth month. According to the survey results, 91 (71%) volunteers had not been diagnosed with coronavirus disease 19 before vaccination. The antibody levels 1 month and 6 months after the second dose of vaccination were significantly higher in those who had been diagnosed with coronavirus disease 19 before vaccination than in those who had not. It was found that age, gender, fast food, or healthy nutrition had no effect on antibody levels. CONCLUSION: Vaccines are very important both to protect against coronavirus disease 19 and to experience only a mild form of the disease. Immunoglobulin class G levels formed after vaccination may be affected by many factors and may decrease over time
Nonflammable Supramolecular Polymer Electrolytes for Flexible and High-Performance Supercapacitor Applications
No full textThe present work reports on high-performance and flexible supercapacitors assembled using a cost-effective and nonflammable electrolyte with activated carbon electrodes. The electrolyte was prepared by rapidly blending a ternary system comprising poly(vinyl alcohol)(P)/glycerol (G)/boric acid (B) hydrogel doped with LiNO3 (Li),─henceforth denoted as PGBLi,─at ambient temperature. Once partial in situ cross-linking occurred between P and B, the polymer electrolytes were cast onto the carbon electrodes. The doped PGBLi hydrogel electrolyte retained excellent flexibility and high ionic conductivity in a broad temperature domain, while the performance of the assembled supercapacitor devices measured at low and high temperatures confirmed the high stability. Moreover, the supercapacitor exhibited 396 F g-1 specific capacitance at 1 A g-1 and 27.41 Wh kg-1, obtained at a power density of 118 W kg-1, while 95.4% capacitive performance was maintained after 10 000 cycles, indicating adequate cyclic stability. Thus, the as-doped PGBLi hydrogel electrolyte is inexpensive, biocompatible, and nonflammable and meets the criteria for flexible wearable electronics; it can be considered for a variety of applications. © 2023 American Chemical Society
Chemical profiling, antioxidant, enzyme inhibition, and anti-cancer effects
No full textHippomarathrum scabrum L. is an endemic medicinal plant in Turkey; however, there have been few studies investigating the phytochemistry and biological properties of these plants has not been investigated. The aim of this work is to determine the chemical composition of different extracts (extracts obtained by using supercritical carbon dioxide extraction, accelerated solvent extraction, homogenizer-assisted extraction, microwave-assisted extraction, and ultrasound-assisted extraction from Hippomarathrum scabrum L., and evaluate their biological properties. The analysis revealed that 5-O-caffeoylquinic acid, rutin, and isorhamnetin 3-O-rutinoside were the main bioactive compounds. The extract obtained by accelerated extraction contains the highest concentration of 5-O-Caffeoylquinic acid (7616.74 +/- 63.09 mg/kg dry extract) followed by the extract obtained by homogenizer-assisted extraction (6682.53 +/- 13.04 mg/kg dry extract). In antioxidant tests, all extracts expressed significant antioxidant activity. Also, cytotoxic and anticancer effects of these plant extracts were detected in the human prostate cancer cell line. Intrinsic apoptotic genes were up-regulated and anti-apoptotic genes were down-regulated in human prostate cancer cells after inhibition concentration dose treatment. The findings are promising, and suggest the use of these plant extracts could be used as natural sources with different biological activities, as well as anticancer agents
Our Approach Using Tutopatch® and Review of Literature
No full textObjectives: To describe the usage and advantages of bovine pericardium mesh (Tutopatch®) in breast reconstruction and to compare different mesh materials used in immediate breast reconstruction. Methods: Our study involved a single-center, retrospective analysis of 103 patients (comprising 114 breasts) who underwent immediate implant-based breast reconstruction using bovine pericardium bovine matrix. The procedures were performed by the same surgical team between April 2018 and May 2023. Results: The rates of early and late complications were examined after a median follow-up period of 30.2 ± 5.5 months. The results revealed that the rates of early complications stood at 9.7%, while late complications were observed in 14.5% of the cases. The most common late complication was seroma formation (7.7%) which six were resolved without any surgical intervention. Conclusion: Tutopatch® can be used as an extension of the muscle to cover the prosthesis. It forms an extra layer over the silicone implant that helps to decrease the complications as capsular contracture and implant exposure. It also represents a significant 85 % reduction in cost when compared to a similar-sized mesh materials. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 . © 2023, Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery
The Role of Preoperative Embolization
No full textAIM: To examine the outcomes of microsurgery only versus combined microsurgery and embolization in treating cerebral arteriovenous malformations (AVM). MATERIAL and METHODS: A total of 62 patients (34 male and 28 female) with Spetzler–Martin grade 3 (n=44) and grade 4 (n=18) AVMs were examined. Thirty-seven patients were treated with a combination of microsurgery + embolization, whereas 25 patients were treated with microsurgery alone. The clinical characteristics of the treatment groups were compared (ruptured/unruptured, eloquent/non-eloquent, modified Rankin scores, duration of surgery, preoperative and postoperative hemoglobin levels, and use of blood products). RESULTS: The number of patients with ruptured or eloquently localized AVMs was more in combination of microsurgery + embolization. On the other hand, the duration, preoperative versus postoperative hemoglobin levels, and usage of blood products did not differ between treatment groups. CONCLUSION: The results of the study showed no superiority of the combined treatment in managing AVMs in parallel to recent meta-analyses. However, a patient-tailored approach is recommended while making the treatment decision for such challenging intracerebral AVM cases. © (2023), (Turkish Neurosurgical Society). All Rights Reserved