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Application of the genetic algorithm to Blume-Emery-Griffiths model: Test cases
(WORLD SCIENTIFIC PUBL CO PTE LTD, 2005) Canko, O; Sahin, M; Erdinc, A
The equilibrium properties of the Blume-Emery-Griffiths (BEG) model Hamiltonian with the arbitrary bilinear (J), biquadratic (K) and crystal field interaction (D) are studied using the genetic algorithm technique. Results are compared with lowest approximation of the cluster variation method (CVM), which is identical to the mean field approximation. We found the genetic algorithm to be very efficient for fast search at the average fraction of the spins, especially in the early stages as the system is far from the equilibrium state. A combination of the genetic algorithm followed by one of the well-tested simulation techniques seems to be an optimal approach. The curvature of the inverse magnetic susceptibility is also presented for the stable state of the BEG model.
Determination of operation time in colorectal diseases: Preoperative chemotherapy application
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2005) Sahin, M; Erikoglu, M; Ozer, S; Tekin, A; Boz, S; Golcuk, M; Avunduk, MC
Background. Our aim was to determine the time it takes for wound healing to return to normal in cases where patients have undergone preoperative chemotherapy. Materials and methods. Eighty-four Wistar-albino rats were included in the study. Twelve of them were placed in the control group (Group 1), with no further drug administration. Another 12 rats were placed in a sham group (Group 11) and were peritoneally injected with 1 cc of isotonic saline solution 5 days a month, for a period of 6 months. The remaining 60 rats were placed in five chemotherapy groups (Groups III-VII) and were administered 20 mg/kg 5-fluorouracil through peritoneal injection, 5 days a month for a period of 6 months. At the end of the sixth cure, 12 rats from the control (Group 1), sham (Group II), and chemotherapy groups (Group III) were operated on, and an intestinal transsection. was applied to the rectosigmoid junction, followed by one-by-one anastomosis using 5/0 vicryl. Other groups (Groups IV-VI) with chemotherapy treatment were operated on at 1-week intervals and subjected to the same procedure. The subjects were reoperated on on the eleventh day. A full-layer 4 x 4 cm piece was removed from the abdominal wall containing the previous incision line at the middle, for tensile strength pressure measurements. In addition, a 4 cm colon segment was removed for bursting pressure measurements. Plasma albumin and tissue hydroxyproline levels were measured, and fibroblast numbers were counted in the sections prepared from the abdominal wall. Results. The control and sham groups were found to be similar to each other with respect to all parameters measured (P > 0.05). Significant reductions were observed in all parameters in the early chemotherapy groups compared with the control and sham groups (P <0.05). All parameters measured in Groups V, VI, and VII were found to be similar to those in the control and sham groups (P <0.05). Conclusion. Wound healing is impaired in rats with chemotherapy, but following the second week after the chemotherapy, disrupted parameters return to their normal levels. (C) 2005 Elsevier Inc. All rights reserved.
An ectopic parathyroid gland in the left axillary region: Case report
(INT COLLEGE OF SURGEONS, 2004) Sahin, M; Er, C; Unlu, Y; Tekin, S; Seker, M
This is a review of ectopic localizations of the parathyroid gland in one case. A hard mobile mass (2 X 2.5 cm) was detected on the right side of the neck of a patient who had previously been given a diagnosis of hyperparathyroidism. Computed tomography showed an adenoma (25 X 35 mm) in the paratracheal region on the right side of the neck. Scintigraphy revealed an activity increase on the right side of the neck and in the left axillary region. Blood measurements were as follows: Ca, 12.7 mEq/l; parathyroid hormone (PTH), 235 U/l; and alkaline phosphatase (ALP), 776 U/l. The patient was operated on to remove the lesions located in the cervical and left axillary regions. Histopathological examination revealed that the lesion in the right cervical region was a parathyroid adenoma, whereas the lesion in the left axillary region was normal parathyroid gland tissue. Parathyroid glands may indicate ectopic locations in very different regions. We think the case presented here is the first case with this axillary location. Scintigraphy, alone or combined with other methods, may be used to determine ectopic localizations.
The effects of dimethyl sulfoxide on liver damage caused by ischemia-reperfusion
(ELSEVIER SCIENCE INC, 2004) Sahin, M; Avsar, FM; Ozel, H; Topaloglu, S; Yilmaz, B; Pasaoglu, H; Avunduk, MC
Introduction. The aim of this study was to investigate the effects of dimethyl sulfoxide on liver damage caused by ischemia-reperfusion after portal vein clamping. Material and methods. Forty New Zealand rabbits were divided into three groups with the portal veins of all the rabbits except the sham group clamped for 30 minutes: group I, sham procedure; group II, control group; and group III, 500 mg/kg DMSO. The drug was administered IM in the left inguinal region 30 minutes before the operation. Blood samples (5 mL) were taken from the animals at 15, 30, and 45 minutes. At the end of the experiment 1 g of liver tissue samples were obtained. Malondialdhyde (MDA), nitric oxide (NO), AST, ALT, and LDH plasma levels were measured in the blood samples. Liver tissue samples stained with hematoxylin eosin were examined under light microscopy for histopathological changes. Finding. The liver enzymes in both clamping groups increased significantly compared with the sham group (P < .01). Enzyme levels of the DMSO group decreased significantly compared to the control clamping group (P < .05). Similar to the enzyme changes, MDA and NO levels increased in the portal vein clamping versus the sham group and decreased in the drug-administered group versus the control clamped group (P < .03). The severity of histopathological changes was less in the DMSO group than in the clamped controls. Conclusion. DMSO decreased the severity of liver damage after portal vein clamping.
Effects of DMSO treatment in an experimental rabbit sepsis model
(MEDIMOND S R L, 2005) Kafali, ME; Duran, A; Sahin, M; Ak, A; Arslan, U; Koylu, O
[Abstract not Available]
Effects of gender on the severity of sepsis
(SPRINGER, 2005) Erikoglu, M; Sahin, M; Ozer, S; Avunduk, MC
Purpose. To investigate the differences between male and female rats and the effects of sex hormones on tissue changes in the lung and liver in a sepsis model. Methods. Sixty Sprague-Dawley rats were divided into six groups of ten. Groups 1 and 2 were the control male and female groups, respectively, subjected only to sepsis; groups 3 and 4 were the male and female groups, respectively, subjected to sepsis, then given 0.04 mg/kg estrogen + progesterone (E-P) intramuscularly (i.m.); and groups 5 and 6 were the male and female groups, respectively, subjected to sepsis, then given 0.5 mg/kg testosterone ( T) i.m. The rats were killed and the histopathological changes in the lung and liver were examined, and plasma endotoxin levels were measured. Results. Histopathological examination revealed less congestion, portal inflammation, and focal necrosis of the liver, and less congestion, edema, and emphysematous and inflammatory changes in the lung in the E-P groups than in the other groups. Moreover, signs of systemic endotoxemia in plasma were proportionally less in the female rats and in the E-P groups than in the male rats and the T groups. Conclusion. Female rats subjected to sepsis showed less liver and lung tissue damage and less systemic endotoxemia than male rats, because of the effects of female sex hormones.
Efficiency of low dose N-acetylcystein therapy on experimental rabbit sepsis model
(MEDIMOND S R L, 2005) Duran, A; Kafali, ME; Sahin, M; Toy, H; Cander, B; Ak, A
[Abstract not Available]
Efficiency of mannitol treatment in an experimental rabbit sepsis model
(MEDIMOND S R L, 2005) Kafali, ME; Duran, A; Sahin, M; Koylu, O; Gul, M; Bayir, A
[Abstract not Available]
Electronic structure of a many-electron spherical quantum dot with an impurity
(AMER PHYSICAL SOC, 2005) Sahin, M; Tomak, M
We investigate the electronic structure of a many-electron spherical quantum dot with and without hydrogenic impurity. The number of electrons is taken as N=18. The density functional theory is used within local density approximation. Total energy, chemical potential, addition energy spectra, and the shell structure are determined and the results obtained are compared for cases with and without impurity. It is observed that the capacitive energy with the impurity increases in the 1s shell with respect to the case without the impurity.
Induction and assessment methods used in experimental adhesion studies
(WILEY, 2005) Ozel, H; Avsar, FM; Topaloglu, S; Sahin, M
Infertility and intestinal obstruction are well-known complications, arising from adhesion formation after intra-abdominal operations. Basic principles of adhesion formation have been found through animal studies. In addition, examination of agents for the prevention of adhesions can be easily made using experimental studies. However, lack of uniformity in study design makes assessment of the efficacy of any prophylactic regimen difficult. In this review, the material and methods used in experimental studies designed for adhesion formation or prevention were evaluated in detail, with experimental studies published in the literature from 1960 to 2003 being evaluated. Several methods for adhesion induction have been described in the literature. Severity of the adhesion varies from method to method, with the main problem being the lack of uniform expression of study results. Extensive use of complex adhesion classification systems should be used to resolve this discordance between experimental studies.
Intensity and temperature dependence of photocurrent of a-Si : H Schottky diodes
(ELSEVIER SCIENCE BV, 2006) Sahin, M; Kaplan, R
The photocurrent of hydrogenated amorphous silicon (a-Si:H) Schottky diode has been studied as a function of light intensity from a HeNe laser, applied electric bias, and temperature, by using a constant photocurrent method. The I-V characteristics and thus fill factor (FF) values were also obtained over the temperature range 173-297 K. The FF increases very little as the temperature is decreased. The exponent in the power relationship I-ph similar to G(gamma) between photocurrent and light intensity was found to be temperature and electric field dependent, and peaked around 260 K measured. The activation energy obtained from thermally activated photocurrent was also found to be electric field dependent. These experimental results are discussed by means of the influence of the trapping of charge carriers on the electric field profile. (c) 2005 Elsevier B.V. All rights reserved.
Open drainage versus overlapping method in the treatment of hepatic hydatid cyst cavities
(INT COLLEGE OF SURGEONS, 1999) Yol, S; Kartal, A; Tavli, S; Sahin, M; Vatansev, C; Karahan, O; Belviranli, M
In order to compare the results of open drainage and overlapping methods, 58 consecutive patients with uncomplicated hepatic hydatid disease were investigated between January 1990 and January 1997. The cavities were obliterated by overlapping method in 26 patients and were left open into the peritoneal cavity following partial pericystectomy in 32 patients. Postoperative complications and follow-up results of ultrasonography (US) and computed tomography (CT) were compared between the two groups. In total, there were 56 cysts in the obliterated group and 83 cysts in the open drainage group. There was no significant difference in age, sex, mean diameter of the cysts, US features:of the cysts according to the Gharbi classification, and median followup. Mean hospital stay was 10 days in the overlapping group and 7.5 days in the open drainage group (P = 0.033). No postoperative complication was observed in the obliterated group and nearly half of the cyst cavities could not be detected in the early postoperative period by US and CT. Pleural effusion (n = 1) and biliary fistula (n = 1) were detected in the open drainage group which disappeared spontaneously. In the open drainage group, US and CT surveillance revealed that the cyst cavities were reduced in size and the echo pattern was changed in the early postoperative period, whereas the appearance changed into pseudotumor view in the late postoperative period. In conclusion, the cyst cavities disappear perfectly in the overlapping group. Treating the cyst cavity by open drainage is an easy, effective and safe technique. Open drainage can be a 'method of choice' for patients with multiple hydatid cysts and for cysts where management is difficult or unamenable to other methods, but the residual cyst cavities may be misinterpreted as a new cyst by an inexperienced radiologist.
Optical constants of CuInSe2 thin films prepared by two-stage process
(IOP PUBLISHING LTD, 2005) Yuksel, OF; Safak, H; Sahin, M; Basol, BM
Thin film CuInSe2 chalcopyrite semiconductors have been prepared on glass substrates by means of two-stage process. The structural properties and atomic compositions of films were determined by energy-dispersive analysis of Xrays (EDAX) and X-ray diffraction (XRD) measurements. Reflectance and transmittance measurements were performed on the films in the photon wavelength range of 300-2200nm. The samples used in the measurements have different Cu/In ratios. The reflectance and transmittance spectra were analyzed on the basis of multiple reflection model considering the absorbing film on a non-absorbing substrate and then complex refractive-index n*(E) n(E) + ik(E) and complex dielectric constant epsilon*(E) = epsilon(1) (E) + iepsilon(2)(E) were determined. It has been concluded that the films having higher Cu/In ratios show stronger absorption at low photon energy region than those having lower Cu/In ratios.
A parabolic quantum dot with N electrons and an impurity
(ELSEVIER SCIENCE BV, 2005) Gulveren, B; Atav, U; Sahin, M; Tomak, M
Ground-state properties of a two-dimensional quantum dot composed of N electrons and an impurity are investigated by the Thomas-Fermi (TF) method at T = 0. The changes induced by the impurity in electron density, chemical potential and total energy are calculated. Calculations are also performed for different number of particles and strength of confinement. The results indicate that Thomas-Fermi approximation is applicable even when the system contains only a few particles. (c) 2005 Elsevier B.V. All rights reserved.
Percutaneous treatment of liver hydatid cysts: Comparison of direct injection of albendazole and hypertonic saline solution
(AMER ROENTGEN RAY SOC, 2005) Paksoy, Y; Odev, K; Sahin, M; Arslan, A; Koc, O
OBJECTIVE. The purpose of this study was to compare the effect of intracystic injection of albendazole and hypertonic saline in patients with liver hydatid disease. MATERIALS AND METHODS. Fifty-nine patients with a total of 109 hydatid cysts were treated percutaneously. In all cases, local anesthesia was applied. Twenty percent hypertonic saline was used in 31 patients (40 cysts, group 1) as the scolicidal agent, and albendazole solution was used in 28 patients (69 cysts, group 2). The PAIR (percutaneous puncture, aspiration, injection, reaspiration) method was applied in group 1. In group 2, we used a different procedure that could be called the PAI (percutaneous aspiration and injection) method. After this procedure, routine sonography and CT examinations were conducted. The results of both groups were compared. RESULTS. Follow-up examinations showed that liver hydatids expanded approximately to their original size after a significant reduction during the first month. In the follow-up period, fluid contents totally disappeared; thickening and irregularities were also observed in the cyst walls and a solid, hyperechogenic, heterogeneous pseudotumor appearance representing a degenerated membrane was seen in all patients. Hypertonic saline solution inactivated the scolices from the beginning of the treatment. However, scolices were inactive in the cysts aspirated 1 month after the procedure in group 2. A significant correlation was noted between elapsed time after the treatment and the cyst size using Wilcoxon's signed rank test (P = 0.000). No difference was seen between two groups in the amount of cyst size reduction using the Mann-Whitney test (p = 0.521). CONCLUSION. In addition to its oral use, albendazole may be injected intracystically as we did in our study. It sterilizes the cyst cavity and affects scolices as well.
Quantum genetic algorithm method in self-consistent electronic structure calculations of a quantum dot with many electrons
(WORLD SCIENTIFIC PUBL CO PTE LTD, 2005) Sahin, M; Atav, U; Tomak, M
In this study, we have calculated energy levels of an N-electron quantum dot. For this purpose, we have used two different techniques, matrix diagonalization and quantum genetic algorithm, to obtain simultaneous solutions of the coupled Schrodinger and Poisson equation in the Hartree approximation. We have determined single particle energy levels, total energy, chemical potential and capacitive energy. We have also compared the results, demonstrated the applicability of QGA to many-electron quantum systems and evaluated its effectiveness.
Reinforcement of the suture line with an ePTFE graft attached with histoacryl glue in duodenal trauma
(CMA-CANADIAN MEDICAL ASSOC, 2006) Saygun, O; Topaloglu, S; Avsar, FM; Ozel, H; Hucumenoglu, S; Sahin, M; Hengirmen, S
Background: Most duodenal injuries are managed with primary repair, but the degree of duodenal-wall injury may threaten the integrity of the primary repair. Therefore, we evaluated whether the primary repair site could be reinforced with histoacryl glue (HAG) or HAG with an expanded polytetrafluoroethylene (ePTFE) mesh. Methods: Grade 3 duodenal injury in the second portion of the rat duodenum was chosen as a standard trauma model. Thirty-three male rats were divided into sham (n = 3), 2-layer primary repair (n = 10), 1-layer primary repair plus HAG application (n = 10) and ePTFE attached with HAG over the 1-layer primary repair site (n = 10) groups. Ten-day survival, adhesion grades and histological assessment were taken as outcome measures. Results: A significant survival advantage was identified in the group that had an ePTFE graft attached with HAG over a 1-layer repair when compared with the group that had a 2-layer primary repair. Adhesion grades were found to be particularly increased in the group that had an ePTFE graft attached with HAG over the primary repair site, moderately increased in the primary repair plus HAG application group and lower in the 2-layer primary repair group. ePTFE graft application was found to be beneficial to coverage of the HAG-dependent empty spaces in the serosal layer. Conclusions: A primary repair site after duodenal trauma or a difficult duodenal stump can be reinforced with the application of HAG or ePTFE graft implantation with HAG.
RF-assisted cystectomy and pericystectomy: A new technique in the treatment of liver hydatid disease
(KARGER, 2006) Sahin, M; Kartal, A; Haykir, R; Cakir, M
Background. Radiofrequency (RF) energy has been used for ablation and resection of liver tumors. Purpose: To present a new technique for the treatment of liver hydatid cyst disease. Material and Methods: Two patients with liver hydatid disease treated with RF energy cauterization and surgical resection are presented. Cystectomy was performed in a female patient aged 35 years and pericystectomy was carried out in another female patient aged 55 years using RF energy cauterization. Blood was not needed during the operation. RITA((R)) System (RITA Model 1500 RF Generator, RITA Medical Systems, Inc., USA) was used during the procedure. Conclusion: Cystectomy and pericystectomy in liver hydatid disease can be successfully performed with the assistance of RF energy. Copyright (c) 2006 S. Karger AG, Basel.
The self-consistent calculation of a spherical quantum dot: A quantum genetic algorithm study
(ELSEVIER SCIENCE BV, 2005) Sahin, M; Tomak, M
In this study, we have calculated the subband energy level, potential profile, and the corresponding wavefunction and chemical potential for different temperatures and donor concentrations in a spherical quantum dot self-consistently. We have also investigated the effect of exchange-correlation potential on the energy levels. In addition, we have checked the applicability of quantum genetic algorithm to a realistic self-consistent quantum dot problem. In all computations, the penetration of wavefunction to the barrier region is taken into account. (c) 2005 Elsevier B.V. All rights reserved.
Series resistance calculation for Ag contacts on single crystal layered p-SnS and p-SnSe compound semiconductors in the wide temperature range
(ELSEVIER SCIENCE BV, 2005) Karadeniz, S; Tugluoglu, N; Sahin, M; Safak, H
This paper summarizes the first results of characteristics parameters obtained from current-voltage (I-V) measurements for Ag/p-SnS and Ag/p-SnSe structure. The reverse and forward bias current-voltage characteristics of Ag Schottky contacts on a Bridgman-Stockbarger grown p-SnS and p-SnSe layered semiconducting material have been measured at various temperatures. We have tried to determine contact properties such as apparent barrier heights Phi(BO), ideality factor n and series resistance R-s. The apparent barrier height and ideality factor calculated by using thermionic emission theory were found to be strongly temperature dependent. Evaluating forward I-V data reveals a decrease at the apparent barrier height, but an increase at the ideality factor with decrease in temperature. It is shown that the values of R-s estimated from Cheung's method were strongly temperature dependent and decreased with increasing temperature. It has been found that both contacts are of Schottky type. (c) 2005 Elsevier B.V. All rights reserved.

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