Capacity Increase for Existing Steel Bridges Using Prestressed Cables

In the present study, a practical approach is proposed for geometric nonlinear analysis of existing steel bridges. The approach is defined by finite element displacement direct rigidity procedure, which is based on an iterative procedure. Tangent rigidity matrix is used for cable truss and/or framed steel structures formed by finite elements. Hence, effects of prestressed cables in system rigidity can be taken into account in the analyses. Moreover, stressing effects on cables are taken into account with equivalent temperature change. The research has three main parts. In the first part, prestressed cables are investigated for capacity increase for steel bridges. In the second part, an iterative procedure is proposed for existing steel bridges that can be used for geometric nonlinear analysis. In the third part, a representative bridge is modeled and analyzed. In the model, first, the representative model is analyzed as it is existing form and then, it is analyzed with prestressed cables in two different forms. So, three different results are investigated for their structural behaviors. In the analyses, geometric nonlinear behavior is investigated and results are evaluated. As a result of the study, capacity change by using stressed cables is defined for existing bridges

Karşıt Akışlı Ranque– Hilsch Vorteks Tüpünün Makine Öğrenmesi Metotları ile Performans Analizi

Bu çalışmada, basınçlı oksijen gazı kullanarak aynı anda hem soğutma hem de ısıtma yapabilen ve kontrol vanası dışında hareketli parçası bulunmayan basit borudan meydana gelen Karşıt Akışlı Ranque-Hilsch Vorteks Tüp (KARHVT) kullanılmıştır. KARHVT’nün tasarımında boru 7 mm iç çapında ve 100 mm gövde uzunluğunda imal edilmiştir. KARHVT’ünde, nozul olarak pirinç, çelik, alüminyum ve polyamid üretilen 2, 3, 4, 5 ve 6 orfisli malzemesi kullanılmıştır. Yapılan deneylerde sıcak akışkan tarafında bulunan kontrol vanası tam açık konumda bırakılmış olup, giriş basıncı ilk 150 kPA olarak ayarlanmıştır. Daha sonra 50 kPa aralıklarla 700 kPa kadar veriler alınmıştır. KARHVT’de çıkan soğuk akışın sıcaklığı (Tsoğ) ve çıkan sıcak akış sıcaklığı (Tsck) ile arasındaki fark (ΔT) cinsinden bulunarak KARHVT’ün performansı optimizasyonu yapılmıştır. KARHVT’nün performansının optimizasyonunu, makine öğrenimi metotlarından Lineer Regresyon (LR), Regresyon Ağaçları (RA) ve Ağaç Toplulukları (AT) yöntemleri kullanılarak literatürdeki eksikliğin tamamlanması amaçlanmıştır. Çalışmada makine öğrenimi metotlarının her birinin analizi için, tüm verinin %80’i eğitim verisi, tüm verinin %20’si ise test verisi olarak kullanılmıştır. Çalışmanın sonunda eğitilen modeller sonunda gerçekleşen tahmin sonuçları ile gerçek deney sonuçları karşılaştırılarak yorumlanmıştır

The Effects of Macroeconomic Indicators on Lending Interest Rates: Evidence from BRICST, MINT, and Fragile Five Countries

This study analyzes the effects of the macroeconomic indicators on the lending interest rates in the leading emerging countries by considering the significance of the interest rates for economic growth since high-level interest rates decrease economic growth and volatile interest rates deteriorate economic stability. In this context, the lending interest rate is considered as the dependent variable; foreign exchange (FX) rates, gross domestic product (GDP), and inflation are included as the independent variables that are the main macroeconomic indicators; annual data from 1990 to 2019 are used, and the panel data analysis is applied. The empirical analysis results reveal that (i) FX rates, GDP, and inflation have a significant effect on the lending interest rates at the panel level; (ii) the significance of these macroeconomic indicators vary at the country level; (iii) GDP is the most influential factor on the lending interest rates at both panel and the country level. The analysis results underline the effects of macroeconomic factors on the lending interest rates. Therefore, countries should apply appropriate policies to lessen the adverse effects of the macroeconomic indicators on the interest rates so that economic growth can be supported by low-level lending interest rates. Hence, emerging countries can benefit from low-level lending interest rates

Application of vascular endothelial growth factor at different phases of intestinal ischemia/reperfusion: what are its effects on oxidative stress, inflammation and telomerase activity?

Background. Intestinal ischemic reperfusion injury (IRI) represents a great challenge in clinical practice, with high morbidity and mortality. Vascular endothelial growth factor (VEGF), asasignal protein, contributes tovasculogenesis and angiogenesis.Objectives. To evaluate the local effectiveness of VEGF following intestinal IRI and its relation with application time.Material and methods. Thirty Wistar albino rats were allocated to5 groups and underwent laparotomy. Thesuperior mesenteric arteries (SMA) were dissected in4 groups, while thecontrol group (GrC) underwent aresection ofsmall and large intestines. The VEGF group (Gr V) received VEGF following SMA dissection, with no further intervention, and theremaining 3 groups were subjected toischemia for 90min through occlusion ofSMA and reperfusion for 4h. Ischemic reperfusion group (Gr I/R) received no additional medication, while theremaining 2 groups received VEGF just before ischemia (Gr V+I/R) and during reperfusion (Gr I/R+V).Results. Both applications of VEGF caused decreases inplasma levels of interleukin6 (IL-6), tumor necrosis factor ? (TNF-?), intestinal malondialdehyde (MDA), oxidized glutathione, protein carbonyl levels, and increases inintestinal total glutathione and superoxide dismutase (SOD) levels. Telomerase activity, which disappeared for Gr I/R, was found to be elevated following both treatment groups. Similarly, the histopathological scores were found better for both treatment groups, but Gr V-I/R represented best outcomes.Conclusions. The findings of our study revealed that VEGF, applied either before ischemia or during reperfusion, iseffective onlocal damage following intestinal IRI. Byinterpreting thebiochemical analysis and histopathological findings, we conclude either treatment option to be considered according to the reason of intestinal IRI

Relationship between interleukin-6 levels and ambulatory blood pressure in women with polycystic ovary syndrome

Objective: To determine 24-hour ambulatory blood pressures (ABP) in patients with polycystic ovary syndrome (PCOS) and its relationship with interleukin-6 (IL-6). Design: Prospective controlled study. Setting: University hospital. Patient(s): Fifty-four PCOS patients. Intervention(s): Ambulatory blood pressure monitoring was conducted. Anthropometric, hormonal, metabolic, and inflammatory parameters, including plasma IL-6, C-reactive protein (CRP), fibrinogen, and nitric oxide (NO), were measured in each subject. Main Outcome Measure(s): Ambulatory blood pressure and plasma IL-6, CRP, fibrinogen, and NO. Result(s): Serum IL-6 levels of PCOS women in the highest systolic blood pressure (SBP) quartile were significantly higher than those of women in the lowest SBP quartile. The high serum IL-6 levels (serum IL-6 level R5.1 pg/mL) were associated with a higher probability of raised SBP (R126 mm Hg), with an odds ratio of 2.2 (95% confidence interval 0.8–7.9). The systolic and diastolic (DBP) blood pressures were significantly related to serum IL-6 levels. The IL-6 levels were positively and significantly correlated with serum CRP levels. Interleukin- 6 and CRP were negatively and significantly correlated with serum NO levels. Conlusion(s): The results suggest that raised plasma IL-6 levels may be related to ambulatory SBP and DBP in PCOS

İNSAN MANDİBULASINDA SONLU ELEMANLAR METODU KULLANILARAK GERİLME ANALİZİ YAPILMASI

In this study use of the finite element method in biomechanics, and an explanation of basicsteps of preparing a FEM model of a mandible, a discussion of the validity of results is the objective. Acomputer FEM model of a mandible is prepared from a real human mandible and stress analysis wasconducted. For this purpose CT sections of the mandible of a 22 year old male was obtained and theimages were scanned and transferred to the computer. In the study the steps of preparing a FEM modelof a human skeleton is explained in detail. By using them a 3 D model of the mandible prepared. One ofthe models is prepared with solid elements; the other is prepared with shell elements. The same loadingswere applied to both of them. The results are compared and it is concluded that there is no importantdifferences between them.Bu çalışmada, sonlu elemanlar metodunun biyomekanikte kullanıldığı bir durum için, modelinhazırlanmasının temel aşamaları ve elde edilen sonuçların geçerliliğinin tartışılması amaçlanmıştır. Birinsan mandibulasının sonlu elemanlar programında gerilme analizini yapmak için bilgisayar modelihazırlanmıştır. Bu amaçla 22 yaşındaki bir erkek mandibulasının bilgisayarlı tomografisi (CT) alınmış,elde edilen görüntüler bilgisayar ortamına aktarılmış ve mandibulanın 3 boyutlu sonlu elemanlarmodeli hazırlanmıştır. Çalışmada modelin hazırlanmasında izlenen adımlar detaylı olarak verilmiştir.Sonlu elemanlar metodu (FEM) ile analizde, mandibulanın kabuk ve tuğla-solid elemanlar kullanılarakelde edilen modelleri ile yapılan gerilme karşılaştırması da verilmiştir. Bu modeller değerlendirildiğindesolid ve kabuk elemanlarla yapılan modellerin yaklaşık aynı mekanik davranışı yansıttığı belirlenmiştir.Kabuk elemanlarla hazırlanan modelin kolay elde ediliyor olması nedeniyle daha kullanışlı olduğugörülmüştür

Increased mean platelet volume associated with extent of slow coronary flow

Background: Slow coronary flow (SCF) is characterized by delayed opacification of epicardial coronary vessels. SCF can cause ischemia and sudden cardiac death. We investigated the association between presence and extent of SCF, and cardiovascular risk factors and hematologic indices. Methods: In this study, 2467 patients who received coronary angiography for suspected or known ischemic heart disease were retrospectively evaluated between April 2009 and November 2010. Following the application of exclusion criteria, our study population consisted of 57 SCF patients (experimental group) and 90 patients with age- and gender-matched subjects who proved to have normal coronary angiograms (control group). Baseline hematologic indices were measured by the automated complete blood count (CBC) analysis. The groups were evaluated for cardiovascular risk factors and medications. Patients were categorized based on the angiographic findings of vessels with or without SCF. Moreover, patients with SCF were divided into subgroups relative to the extent of SCF. Results: Among the 147 patients (mean age 52.7 ± 10.0, 53.7% male), mean platelet volume (MPV) ranged from 6.5 fL to 11.7 fL (median 7.9 fL, mean 8.1 ± 0.8 fL). Diabetes (OR = 3.64, 95% CI 1.15–10.43, p = 0.03), hypercholesterolemia (OR = 4.94, 95% CI 1.99–12.21, p = 0.001), smoking (OR = 3.54, 95% CI 1.43–8.72, p = 0.006), hemoglobin (OR = 1.69, 95% CI 1.22–2.36, p = 0.002), and MPV (OR = 2.52, 95% CI 1.43–4.44, p = 0.001) were found to be the independent correlates of SCF presence. Only MPV (OR = 2.13, 95% CI 1.05–4.33, p = 0.03) was identified as an independent correlate of extent of SCF. Conclusions: Elevated baseline MPV value was found to be an independent predictor of the presence and extent of SCF

Activin Receptor Ligand Blocking and Cancer Have Distinct Effects on Protein and Redox Homeostasis in Skeletal Muscle and Liver

Muscle wasting in cancer cachexia can be alleviated by blocking activin receptor type 2 (ACVR2) ligands through changes in protein synthesis/degradation. These changes in cellular and protein metabolism may alter protein homeostasis. First, we elucidated the acute (1-2 days) and 2-week effects of blocking ACVR2 ligands by soluble activin receptor 2B (sACVR2B-Fc) on unfolded protein response (UPR), heat shock proteins (HSPs) and redox balance in a healthy mouse skeletal muscle. Second, we examined UPR, autophagy and redox balance with or without sACVR2B-Fc administration in muscle and liver of C26 tumor-bearing mice. The indicators of UPR and HSPs were not altered 1-2 days after a single sACVR2B-Fc administration in healthy muscles, but protein carbonyls increased (p <0.05). Two weeks of sACVR2B-Fc administration increased muscle size, which was accompanied by increased UPR markers: GRP78 <0.05), phosphorylated elF2 alpha <0.01) and HSP47 (p <0.01). Additionally, protein carbonyls and reduced form of glutathione increased (GSH) (p <0.05). On the other hand, C26 cancer cachexia manifested decreased UPR markers (p-elF2 alpha, HSP47, p-JNK; p <0.05) and antioxidant GSH (p <0.001) in muscle, whereas the ratio of oxidized to reduced glutathione increased (GSSG/GSH; p <0.001). Administration of sACVR2B-Fc prevented the decline in GSH and increased some of the UPR indicators in tumor-bearing mice. Additionally, autophagy markers LC3II/I (p <0.05), Beclin-1 (p <0.01), and P62 (p <0.05) increased in the skeletal muscle of tumor-bearing mice. Finally, indicators of UPR, PERK, p-elF2 alpha and GRP78, increased (p <0.05), whereas ATF4 was strongly decreased (p <0.01) in the liver of tumor-bearing mice while sACVR2B-Fc had no effect. Muscle GSH and many of the altered UPR indicators correlated with tumor mass, fat mass and body mass loss. In conclusion, experimental cancer cachexia is accompanied by distinct and tissue-specific changes in proteostasis. Muscle hypertrophy induced by blocking ACVR2B ligands may be accompanied by the induction of UPR and increased protein carbonyls but blocking ACVR2B ligands may upregulate antioxidant protection.Peer reviewe

Effects of muscular dystrophy, exercise and blocking activin receptor IIB ligands on the unfolded protein response and oxidative stress

Protein homeostasis in cells, proteostasis, is maintained through several integrated processes and pathways and its dysregulation may mediate pathology in many diseases including Duchenne muscular dystrophy (DMD). Oxidative stress, heat shock proteins, endoplasmic reticulum (ER) stress and its response, i.e. unfolded protein response (UPR), play key roles in proteostasis but their involvement in the pathology of DMD are largely unknown. Moreover, exercise and activin receptor IIB blocking are two strategies that may be beneficial to DMD muscle, but studies to examine their effects on these proteostasis pathways are lacking. Therefore, these pathways were examined in the muscle of mdx mice, a model of DMD, under basal conditions and in response to seven weeks of voluntary exercise and/or activin receptor IIB ligand blocking using soluble activin receptor-Fc (sAcvR2B-Fc) administration. In conjunction with reduced muscle strength, mdx muscle displayed greater levels of UPR/ER-pathway indicators including greater protein levels of IREloc, PERK and Atf6b mRNA. Downstream to IREloc and PERK, spliced Xbpl mRNA and phosphorylation of elF2oc, were also increased. Most of the cytoplasmic and ER chaperones and mitochondrial UPR markers were unchanged in mdx muscle. Oxidized glutathione was greater in mdx and was associated with increases in lysine acetylated proteome and phosphorylated sirtuin 1. Exercise increased oxidative stress when performed independently or combined with sAcvR2B-Fc administration. Although neither exercise nor sAcvR2B-Fc administration imparted a clear effect on ER stress/UPR pathways or heat shock proteins, sAcvR2B-Fc administration increased protein expression levels of GRP78/BiP, a triggering factor for ER stress/UPR activation and TxNIP, a redox-regulator of ER stress-induced inflammation. In conclusion, the ER stress and UPR are increased in mdx muscle. However, these processes are not distinctly improved by voluntary exercise or blocking activin receptor IIB ligands and thus do not appear to be optimal therapeutic choices for improving proteostasis in DMD. (C) 2016 Elsevier Inc. All rights reserved.Peer reviewe

The effects of Covid-19 on physical medicine and rehabilitation in Turkey in the first month of pandemic

Objectives: The outbreak of novel coronavirus-2019 (COVID-19) has affected Turkey very seriously, as well as all around the world. Many urgent and radical measures were taken due to the high contagious risk and mortality rate of the outbreak. It is noteworthy that isolation recommendations and the provision of health services for pandemic have a negative impact on Physical Medicine and Rehabilitation (PMR) services. In this study, we aimed to evaluate the effects of COVID-19 on the PMR services and physiatrists immediately after the first month of pandemic in Turkey. Patients and methods: An online survey consisting of 45 items was sent to the members of the Turkish Society of Physical Medicine and Rehabilitation. The main goal of the survey was to evaluate the changes in the provided service of PMR and conditions of physiatrists one month after the first reported COVID-19 case in Turkey. Results: A total of 606 PMR specialists and residents responded to the survey. The mean number of the patients visited the outpatient clinics was 148.2 +/- 128.5 per week before the pandemic, it significantly decreased to 23.4 +/- 33.1 per week after the first month of the reported first COVID-19 case. Similarly, the mean number of the patients of inpatient service significantly decreased from 21.7 +/- 39.3 per week to 2.5 +/- 10.0 per week after the first month of the pandemic. Most of the residents (69%) reported that their training was seriously affected due to pandemic. From the economic aspect, 69.2% of the participants who were working at private hospitals reported a decrease in their monthly salary, and 21% of them were sent to an unpaid vacation. A total of 21.9% of private-practice institutions paused their services. During the first month, 46.9% of the participants were assigned to the different services such as COVID-19 inpatient service, emergency or COVID-19 outpatient clinics. According to the Republic of Turkey, Ministry of Health guideline and algorithm, 15.7% of the physicians were in the category of healthcare workers with suspected COVID-19. Conclusion: The COVID-19 pandemic affected seriously both the services and the PMR physicians as early as the first month. This effect is expected to become worse, when the duration of pandemic prolongs. Proper arrangements and measures should be planned to ameliorate the negative effects of the pandemic on the patients and PMR physicians