Scopus İndeksli Yayınlar Koleksiyonu
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Article Citation Count: 30Effect of low-dose methyl prednisolone on serum cytokine levels following extracorporeal circulation(Arnold Hodder Headline Plc., 1999) Yılmaz, Mert; Ener, Serdar; Akalın, Halis; Sağdıç, Kadir; Serdar, O. Akin; Cengiz, MeteThe systemic inflammatory response to cardiopulmonary bypass (CPB) is associated with increased production of cytokines. This systemic inflammatory response characterized by the activation of interleukin-6 (IL-6) and interleukin-8 (IL-8) during and after CPB is well documented. A prospective randomized double-blind study was performed so as to understand the effects of low-dose methyl prednisolone sodium succinate (MPSS) on the circulating levels of serum cytokines and clinical outcome. Twenty patients were randomly divided into two groups on the basis of the administration of low-dose(1 mg/kg) MPSS in = 10) and placebo in = 10) into the pump prime solution. All patients were scheduled to undergo a primaryConference Object Citation Count: 0A synthesis tool for the multiplierless realization of FIR-based multirate DSP systems(IEEE, 2000) Yurdakul, ArdaIn this study a synthesis tool using a novel multirate folding technique which handles each FIR filter in a multirate DSP system as a single node is developed. A new architecture is presented for the multiplierless realization of a fold of multirate FIR filters. This synthesizer fully exploits the redundancies (i.e. `idle' and `missing' cycles) and common terms in multirate systems without sacrificing from overall system quality to produce multiplierless multirate systems. It also enables the usage of a single clock for all parts of the circuit.Article Citation Count: 10Acute gastrointestinal complications after open heart surgery(Asia Publishing Exchange Pte Ltd, 2000) Akpınar, Belhhan; Sağbaş, Ertan; Güden, Mustafa; Kemertas, Kubilay; Sönmez, Bingür; Bayındır, Osman; Demiroğlu, CemşidRetrospective analysis revealed that 24 of 4401 adult patients (0.5%) developed severe gastrointestinal complications after open heart surgery during a 3-year period from January 1995. There were 4 women (17%) and 20 men (83%). Mean age was 61.7 ± 2.02 years. Gastrointestinal bleeding (33.3%) mesenteric ischemia (20.8%) pancreatitis (20.8%) hepatic dysfunction (16.7%) and cholecystitis (16.7%) were the most common complications. Mortality was 41.7% (10 patients). During the same period mortality in the patients who did not develop gastrointestinal complications was 1.89% (p < 0.0001). Emergency basis reoperation combined operations peripheral vascular disease diabetes mellitus chronic lung disease and impaired left ventricle function were found to be risk factors for the development of postoperative gastrointestinal complications.Article Citation Count: 17Off-pump coronary artery bypass grafting with use of the octopus 2 stabilization system(2000) Akpınar, Belhhan; Güden, Mustafa; Sağbaş, Ertan; Sanisoğlu, İlhan; Aytekin, Vedat; Bayındır, OsmanBackground: The treatment of coronary artery disease has evolved rapidly over the last two decades. The gold standard of surgical revascularization, the on-pump coronary artery bypass graft, has been challenged by the development of percutaneous transluminal coronary angioplasty. Our experience with the alternative of the off-pump ("beating heart") coronary artery bypass (OPCAB) technique during a period of 18 months suggests that OPCAB avoids the complications of cardiopulmonary bypass and offers patients the benefit of long-term graft patency that greatly exceeds that of current endovascular technologies. Methods: The early results of 126 OPCAB procedures performed through a medial sternotomy incision during a period of 18 months were evaluated. There were 80 male and 46 female patients, with a mean age of 69 +/- 4.3 years. Emergency cases and reoperations were not included. A total of 268 anastomoses were performed, with a mean number of 2.12 anastomoses per patient. Conduits used, with their percentage of use, were: left internal thoracic artery (LITA) (100%), right internal thoracic artery (11.1%), greater saphenous vein (84%), and radial artery (31%). In 72% of the cases, off-pump surgery was chosen because of patient risk factors such as atherosclerotic aortic disease, previous cerebrovascular accident or carotid artery disease, renal dysfunction, malignancy or poor left ventricular function. Results: There was no operative mortality. One-month postoperative mortality was three patients (2.3%). Two died because of mesenteric ischemia, and the other death was due to cardiac failure. Seventy-one patients had a control angiogram before discharge. The patency of LITA anastomosis was 100% while overall patency rate was 95%. In 43 patients for whom an angiogram could not be performed, a Thallum 201 stress test was performed three months postoperatively. Thirty-eight patients had a normal test while five patients showed signs of ischemia. These patients had a control angiogram: in four patients anastomoses were patent, but in one patient there was a severe narrowing of a venous anastomosis to the distal right coronary artery (RCA) which was corrected with angioplasty. In the whole series eight patients (6.3%) refused to have any control examination. Conclusions: Our early results suggest that off-pump CABG with Octopus 2 (Medtronic, Inc., Minneapolis, MN) can be a good alternative in high risk patients who need multiple vessel revascularization.Article Citation Count: 33Primary epiploic appendagitis CT manifestations(Elsevier Science Inc, 2000) Şırvancı, Mustafa; Tekelioğlu, Mehmet H.; Duran, Cihan; Yardımcı, Hakan; Onat, Levent; Özer, KadirInflammation of an epiploic appendage is considered to be a rare cause of acute abdomen. Recently it has been reported that typical computed tomography (CT) findings of primary epiploic appendagitis (PEA) provide a definitive diagnosis in most of the cases. However since these papers are only few they are easily overlooked by the practicing radiologists. Our purpose is to add four new cases to the existing literature and to perform a review of the literature. (C) 2001 Elsevier Science Inc. All rights reserved.Article Citation Count: 18Off-pump coronary artery bypass grafting with use of the octopus 2 stabilization system.(2000) Akpinar,B.; Güden,M.; Sagbas,E.; Sanisoglu,I.; Aytekin,V.; Bayindir,O.BACKGROUND: The treatment of coronary artery disease has evolved rapidly over the last two decades. The gold standard of surgical revascularization, the on-pump coronary artery bypass graft, has been challenged by the development of percutaneous transluminal coronary angioplasty. Our experience with the alternative of the off-pump ("beating heart") coronary artery bypass (OPCAB) technique during a period of 18 months suggests that OPCAB avoids the complications of cardiopulmonary bypass and offers patients the benefit of long-term graft patency that greatly exceeds that of current endovascular technologies. METHODS: The early results of 126 OPCAB procedures performed through a medial sternotomy incision during a period of 18 months were evaluated. There were 80 male and 46 female patients, with a mean age of 69 +/- 4.3 years. Emergency cases and reoperations were not included. A total of 268 anastomoses were performed, with a mean number of 2.12 anastomoses per patient. Conduits used, with their percentage of use, were: left internal thoracic artery (LITA) (100%), right internal thoracic artery (11.1%), greater saphenous vein (84%), and radial artery (31%). In 72% of the cases, off-pump surgery was chosen because of patient risk factors such as atherosclerotic aortic disease, previous cerebrovascular accident or carotid artery disease, renal dysfunction, malignancy or poor left ventricular function. RESULTS: There was no operative mortality. One-month postoperative mortality was three patients (2.3%). Two died because of mesenteric ischemia, and the other death was due to cardiac failure. Seventy-one patients had a control angiogram before discharge. The patency of LITA anastomosis was 100% while overall patency rate was 95%. In 43 patients for whom an angiogram could not be performed, a Thallum 201 stress test was performed three months postoperatively. Thirty-eight patients had a normal test while five patients showed signs of ischemia. These patients had a control angiogram: in four patients anastomoses were patent, but in one patient there was a severe narrowing of a venous anastomosis to the distal right coronary artery (RCA) which was corrected with angioplasty. In the whole series eight patients (6.3%) refused to have any control examination. CONCLUSIONS: Our early results suggest that off-pump CABG with Octopus 2 (Medtronic, Inc., Minneapolis, MN) can be a good alternative in high risk patients who need multiple vessel revascularization.Article Citation Count: 9VLSI implementation of GRBF (Gaussian Radial Basis Function) networks(IEEE, 2000) Çevikbaş, I. Can; Öğrenci, Arif Selçuk; Dündar, Günhan; Balkır, SinaA GRBF network is designed for VLSI implementation. Building blocks of the network consist mainly of analog circuits: op-amp multiplier multiplying DAC (digital to analog converter) floating resistor summer and exponentiator. Parameters of the network (center width of the Gaussian function and output layer weights) are represented digitally for convenient interfacing. It is shown that individual GRBF units allow independent tuning of center width and amplitude. Several network structures are simulated as function approximation examples and the performance is verified to be satisfactory.Article Citation Count: 21Going against the national cultural grain: a longitudinal case study of organizational culture change in Turkish higher education(Carfax Publishing, 2000) Herguner, Gülten; Reeves, Nigel B.R.This paper presents results of a longitudinal case study inquiry into the measurement of organizational culture change through the implementation of total quality management (TQM) concepts in a higher education context. The inquiry deals with the relationship between national culture and the company corporate culture the consequences of manager style change for TQM implementation and how culture change can be measured adequately. The results are achieved by the utilization of external (quantitative) and internal (qualitative) measurement devices. Limitations consequent upon the number of participants and the dual role of the researcher indicate the potential value of further investigations into the topic using these devices. The main conclusion is that the maintenance of TQM systems without continued senior managerial commitment may not suffice to secure change and prevent a reversion to earlier cultural patterns. Certainly since the findings of this inquiry are limited to one case study it would be unwise to assume that similar results would necessarily pertain in other higher education contexts. Nevertheless we are of the view that the findings are suggestive of the pressures imposed on organizational change by national cultural patterns. The devices implemented for measuring organizational cultural change while not designed for that purpose have however yielded sufficiently well-defined results to suggest the value of similar implementations to gain insight into the topic in further higher education and other organizational contexts.Article Citation Count: 23The use of the 5-HT3-receptor antagonist ondansetron for the treatment of postcardiotomy delirium(W.B. Saunders Co Ltd, 2000) Bayındır, Osman; Akpınar, Belhhan; Can, Erol; Güden, Mustafa; Sönmez, Bingür; Demiroğlu, CemşidObjective:To evaluate the effect of the 5-HT3-receptor antagonist ondansetron in patients with postcardiotomy delirium. Design: Prospective study. Setting: University hospital. Participants: Thirty-five patients who had undergone coronary artery bypass graft surgery. Interventions: Thirty-five patients 23 men and 12 women who developed delirium in the intensive care unit after coronary artery bypass graft surgery were included. Mean patient age was 51.3 years (range 36 to 79 years). A mental status scoring scale was developed and patients were scored 0 to 4 according to their delirium status after confirming that there were no correctable metabolic abnormalities as an underlying cause for delirium. Normal behavior was scored as 0 and severe verbal and physical agitation was scored as 4. Patients received a single dose of ondansetron 8 mg intravenously and were reevaluated 10 minutes later. Measurements and Main Results: Before the treatment 7 patients had a score of 2 (20)Letter Citation Count: 1Long-standing seroma after ultrasound-assisted liposuction(Lippincott Williams & Wilkins, 2001) Ağaoğlu, Galip; Erol, O. Onur[Abstract Not Available]Letter Citation Count: 4The use of composite stentless valves with graft extension for the treatment of ascending aortic aneurysms(Elsevier Science Bv, 2001) Akpınar, Belhhan; Güden, Mustafa[Abstract Not Available]Article Citation Count: 0The stability constants of the rare earth complexes with trimetaphosphoric acid(Soc Chimica Italiana, 2001) Şungur, Şana KutunThe stability constants of the complexes formed between the rare earth metal ions and the anion of trimetaphosphoric acid have been determined at a temperature of 20 degreesC and an ionic strength of mu =0.1 by the ion-exchange equilibrium method. The investigations indicate that stabilities of complexes increased from La to Lu.The highest and the lowest stability constant values (beta) were found to be 7.76 and 3.82 for Lu3+ and La3+ respectively.Article Citation Count: 12Acute aortic valve regurgitation secondary to blunt chest trauma(Texas Heart Inst., 2001) Ünal, Mehmet; Demirsoy, Ergun; Göğüş, Abdullah; Arbatlı, Harun; Hamzaoğlu, Azmi; Sönmez, BingürBlunt injury to the cardiac valves leads to progressive acute ventricular failure which often requires urgent surgical management In this case report we describe an acute aortic valve rupture caused by air-bag inflation during an automobile accident. Laceration of an aortic valve cusp was treated successfully with urgent aortic valve replacement. A concomitant orthopedic injury was treated electively 15 days after cardiac surgery. Acute aortic valve rupture is a very rare complication of blunt chest trauma. We discuss how to diagnose and manage this potentially catastrophic event.Article Citation Count: 0Parameter quantization effects in Gaussian potential function neural networks(World Scientific and Engineering Academy and Society, 2001) Karakuş, Erkan; Öğrenci, Arif Selçuk; Dündar, GünhanIn hardware implementations of Gaussian Potential Function Neural Networks (GPFNN) deviation from ideal network parameters is inevitable because of the techniques used for parameter storage and implementation of the functions electronically resulting in loss of accuracy. This loss in accuracy can be represented by quantization of the network parameters. In order to predict this effect theoretical approaches are proposed. One-input one-output GPFNN with one hidden layer have been trained as function approximators using the Gradient Descent algorithm. After the training the network parameters (means and standard deviations of the hidden units and the connection weights) are quantized up to 16-bits in order to observe the percentage error on network output stemming from parameter quantization. Simulation results are compared with the predictions of the theoretical approach. Consequently the behaviour of the network output has been given with combined and separate parameter quantizations. Moreover given the allowed percentage error for the network a method is proposed where the minimum number of bits required for quantization of each parameter could be determined based on the theoretical predictions.Letter Citation Count: 3Long-standing seroma after ultrasound-assisted liposuction(Lippincott Williams and Wilkins, 2001) Aaolu,G.; Erol,O.[No abstract available]Article Citation Count: 2The evaluation of microbial contamination in platelet concentrates prepared by two different methods(Pergamon-Elsevier Science Ltd, 2001) Kocazeybek, Bekir Sami; Arabaci, Ümit; Akdur, Hülya; Sezgic, Metin; Erentürk, SelimThe microbial contamination of platelet concentrates (PCs) prepared by two different methods both with a high risk of bacterial contamination during preparation and storage were evaluated. For apheresis platelets the concentrates were obtained using the Haemonetics MCS 3P device. For the random method platelets were obtained by two phase centrifugation in the Heraeus Cryofuge 8500 I device using the Kansuk 3-way bags which permit storage for five days. 1620 platelet pheresis units prepared by apheresis and 9838 units prepared by the random method were included in the study. Of the 11458 PCs studied 32 (0.27%) were false positives and 24 (0.2%) were real positives. All of the positive results occurred in platelets prepared by the random method. C. xerosis and S. epidermidis S. hominis Alpha-hemolytic streptococci all flora of the skin were isolated in the contaminated concentrates. The risk of microbial contamination of PCs prepared both by apheresis and from whole blood continues at a low rate although the products were collected into specific bags following rules including appropriate disinfection of the skin correct centrifugation collection time and optimal storage conditions including temperature and agitation. These results again emphasize the importance of. obeying phlebotomy rules and hand disinfection of the person who collects the blood as well as the need for careful skin decontamination of the donor during donation. (C) 2001 Elsevier Science Ltd. All rights reserved.Article Citation Count: 9Anterior instrumentation for adolescent idiopathic scoliosis(Springer Verlag, 2001) Göğüş, Abdullah; Talu, Ufuk; Akman, Sümeyra; Sar, Can; Hamzaoğlu, Azmi; Eralp, LeventThirty-two patients with adolescent idiopathic scoliosis underwent anterior fusion with rigid single rod (third generation instrumentation) and titanium mesh cages. The mean follow-up was 31 (24-45) months and the mean age was 14.9 years. There were 8 patients with King type I 10 with type II 6 with type III 4 with type IV and 4 with lumbar curves. Titanium mesh cages were used in all the lumbar procedures and at the cranial and caudal ends of the instrumented area in thoracic cases. All the patients were immobilized in an orthosis for 3-6 months postoperatively. Mean preoperative primary coronal Cobb angle of 56 degrees was improved to 8.6 degrees. Average correction rate was 84%. Sagittal balance was restored with a mean thoracic kyphosis of 28 degrees and a mean lumbar lordosis of 38 degrees. Spontaneous secondary curve decompensation did not occur and postoperative thoracolumbar junctional kyphosis was not seen. One case had to be revised due to proximal screw pull out and loss of correction.Article Citation Count: 20Ondansetron hydrochloride for the treatment of delirium after coronary artery surgery(Mosby Inc, 2001) Bayındır, Osman; Güden, Mustafa; Akpınar, Belhhan; Sanisoğlu, İlhan; Sağbaş, Ertan[Abstract Not Available]Article Citation Count: 1Screening of a stentless valve with electron beamed tomograpy 5 years after operation(2001) Akpınar, Belhhan; Güden, Mustafa; Memişoğlu, Esat I.[Abstract Not Available]Article Citation Count: 62Interactions of polyacrylamide polymer with bentonite in aqueous systems(Elsevier Science Bv, 2001) Güngör, Nurfer; Karaoğlan, SThe flow properties of natural Ca bentonite and Na bentonite-water systems were studied after adding an anionic polyacrylamide (PAM) polymer. The effect of the PAM has also been investigated at different quantities. The experimental results are discussed in terms of bentonite forms and concentration of PAM. Besides measurement of theological properties of Ca bentonite + PAM and Na bentonite + PAM systems have been examined in detail through XRD FT-IR and DTA analyses. (C) 2001 Elsevier Science B.V. All rights reserved.
