Beaulieu-Xie Gölgelemeli Sönümlü Kanallar İçin Efektif Kanal Kapasite İfadesinin Kuramsal Türetimi

Bu çalışma, alıcı-verici arasındaki hattın tek ve Beaulieu-Xie gölgelemeli (BX-shadowed, BX-S) sönümlenmeye sahip olduğu bir sistem için efektif kanal kapasitesi (effective channel capacity, Ceff) analizini sunmaktadır. Çalışmada Ceff ifadesi kuramsal olarak türetilmekte, türetimler için BX-S sönümlenmesine ait olasılık yoğunluk fonksiyonundan (probability density function, PDF) yararlanılmaktadır. Ceff ifadesinin doğruluğu bilgisayar benzetimleri ile gösterilmeye çalışılmakta, farklı parametre değişimleri ile çeşitli senaryolar incelenmektedir

The antibacterial effect of mesenchymal stem cells on graft infections: An experimental study

WOS: 000450917400008PubMed: 32082799Background: In this study, we aimed to investigate the antibacterial effects of mesenchymal stem cells, compared to tigecycline, on graft infection related with methicillin-resistant Staphylococcus epidermidis in a rat model. Methods: A total of 42 male adult Wistar rats (age >6 months; weight 300 to 350 g) were divided into six groups including seven rats in each. Group 0 did not undergo any procedure; Group 1 was infected, but untreated; Group 2 was infected and treated with tigecycline without graft placement; Group 3 was infected and received mesenchymal stem cells without graft placement; Group 4 was infected and treated with tigecycline after graft placement; Group 5 was infected and treated with mesenchymal stem cells after graft placement. The pockets created were either left empty or implanted with Dacron grafts. Treatment was commenced at 48 h. Specimens were collected on Day 13. Perigraft tissues were evaluated histopathologically and bacterial colony numbers were counted. Results: No bacterial colonization was observed in Group 0, whereas there was a significant colonization in Group 1. Complete eradication was achieved in Group 2 and Group 3 (graft-free groups), and near-complete eradication was achieved in Group 4 and Group 5 (graft-implanted groups). The histopathological findings significantly differed between Group 1-Group 2 and between Group 1-Group 3 (graft-free groups). The histopathological findings were similar between Group 2-Group 3 and between Group 4-Group 5. Conclusion: Our study results suggest that mesenchymal stem cells may be a novel, contemporary alternative to antibiotherapy and may decrease the bio-burden of Staphylococcus at the infected graft areas, and mesenchymal stem cell treatment may be as effective as tigecycline

Very short term pitch angle optimization in wind turbines: A machine learning approach

This paper proposes a pitch angle forecasting model based on the k-nearest neighbor classification. Air temperature, atmosphere pressure, wind direction, wind speed, rotor speed and wind power parameters were represented as a 6-dimensional attribute tuple in the forecasting model. Euclidean, Manhattan and Minkowski distance metrics for measuring the proximity between training and test tuples, mean absolute, mean absolute percentage, and normalized root mean square error metrics for measuring the forecasting accuracy were embedded into the forecasting model. The k-nearest neighbor classifier with Manhattan distance metric for k=1 achieved MAE, MAPE and NRMSE as 0.001°, 0.245% and 0.324%, respectively as the best forecasting accuracy. However, as the worst forecasting accuracy, MAE, MAPE and NRMSE were achieved as 0.015°, 3.236% and 2.613%, respectively for Minkowski distance metric and k=10

Effects of mesenchymal stem cell and amnion membrane transfer on prevention of pericardial adhesions

WOS:000582567600009Background: To investigate and compare the antiadhesive/antifibrotic effects of mesenchymal stem cells (MSC) and amnion membrane transfer (AMT) in a rat model. Material and methods: Three experimental and sham groups were formed using 30 Wistar-Albino rats. AMT and MSC were applied to the related groups. The control group was not treated. After 12 weeks follow-up, intracardiac blood and cardiac-pericardiac tissue samples were taken. The severity of adhesions and fibrosis were scored macroscopically and microscopically with Hematoxylin/ Eosin and Masson's trichrome staining. TNF-alpha, TGF-beta, IL-1, PDGF, FGF, VEGF and Caspase-3 levels were measured with the ELISA method. Results: Severe adhesions were observed in the AMT and control groups, but no adhesion was present in the MSC group. Pericardial thickness, increased vascularity, fibrosis, and collagen accumulation were similar between control and AMT groups, but were less in Sham and MSC groups. Between MSC and AMT groups, only Caspase-3 level was different, which is an apoptosis marker. Conclusion: The positive effects of MSC on adhesion, which we achieved in our study, suggest that it may prevent adhesion. AMT did not provide a positive effect. The correlation of Caspase-3 with postoperative adhesion/fibrosis should be examined in more detail

Design of a parameter determination system for non-isolated converter topologies

Nowadays, power electronics systems developed need small size, reliable, high quality and efficient switch mode power supplies. However, switch mode power supplies also require determining the operating parameters accurately for achieving intended energy conversion effectively and faultlessly. In this study, an interactive and object oriented parameter determination system was designed for Buck, Boost, Buck-Boost and Cuk converter topologies. Users have used the system interface easily through the interactivity of the system and the user requests have been accomplished quickly through the object oriented programming. Accuracy and reliability of the system have been tested separately for each type of the converter and it has been shown that the performance in the process of determining the parameters of the system is effective and optimum

Performance of Two-Hop Relay Assisted Decode-and-Forward Transmission under Mixed Fading Environments

WOS: 000349838500011This study analyses the performance of two-hop decode-and-forward (DF) relaying protocol under mixed faded channels by evaluating outage probability (P-out) and average bit-error probability (ABEP). It is assumed that the channel between source and relay is Rayleigh fading, whereas the relay-destination link is subject to Weibull fading. First, a closed-form expression is formulated for P-out and then it is used to obtain ABEP for the considered system model. The ABEP performance of two-hop DF relaying is presented for M-ary phase shift keying (M-PSK) signaling with different constellation sizes. Moreover, the proposed analytical expressions are verified by simulations that present the correctness of the derived formulas

Mid-term results in the treatment of varicose veins with N-butyl cyanoacrylate

KOCARSLAN, AYDEMIR/0000-0002-4151-7087; EROGLU, Erdinc/0000-0003-1146-6677; Kocarslan, Aydemir/0000-0003-3874-8762WOS: 000416005700004PubMed: 28669248Aim To present mid-term results of patients with varicose veins treated with N-butyl cyanoacrylate (VariClose (R)), a nontumescent endovenous ablation technique. Patients and method Endovenous ablation was performed on 180 patients with saphenous vein incompetence between May and October 2014. One hundred sixty-eight subjects capable of being followed-up for 30 months were included. Patients' pre- and postoperative data were recorded. Results Procedures were performed on the great saphenous vein in 159 patients and on the small saphenous vein in nine patients. Saphenous vein diameters ranged between 5.5mm and 14mm. Full ablation was achieved in all patients following the procedure. No complications were encountered. Patients were monitored for 30 months. Ablation rates were 100% at the 3(rd) month, 98.3% at the 6(th) month, 96.6% at 1 year, and 94.1% at 30 months. Mean venous clinical severity score was 10.2 before procedures, decreasing to 3.9 at 3 months, 4.2 at 6 months, 2.9 at 12 months, and 2.7 at 30 months (p=0.000). Conclusion Due to its high success rate, absence of complications, no tumescent anesthesia requirement and high patient satisfaction, endovenous ablation with N-butyl cyanoacrylate is a good method. However, long-term follow-up results are now needed