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A Gürses

Publications and source records attributed to A Gürses.

15 recordsLinked to original sources
PubMed2005

Production of granular activated carbon from waste Rosa canina sp. seeds and its adsorption characteristics for dye.

An activated carbon was developed from Rosa canina sp. seeds, characterized and used for the removal of methylene blue (basic dye) from aqueous solutions. Adsorption studies were carried out at 20 degrees C and various initial dye concentrations (20, 40, 60, 80, and 100 mg/L) for different times (15, 30, 60, and 120 min). The adsorption isotherm was obtained from data. The results indicate that the adsorption isotherm of methylene blue is typically S-shaped. The shape of isotherm is believed to reflect three distinct modes of adsorption. In region 1, the adsorption of methylene blue is carried out mainly by ion exchange. In region 2 by polarizations of pi-electrons established at cyclic parts of the previously adsorbed methylene blue molecules is occurred. However, it is not observed any change at the sign of the surface charge although zeta potential value is decreased with increase of amount adsorbed. In region 3, the slope of the isotherm is reduced, because adsorption now must overcome electrostatic repulsion between oncoming ions and the similarly charged solid. Adsorption in this fashion is usually complete when the surface is covered with a monolayer of methylene blue. To reveal the adsorptive characteristics of the produced active carbon, porosity and BET surface area measurements were made. Structural analysis was performed using SEM-EDS. The produced active carbon has the specific surface area of 799.2 m2 g-1 and the iodine number of 495 mg/g.

Adsorption↗
PubMed2005

The adsorption kinetics of the cationic dye, methylene blue, onto clay.

In this study, adsorption kinetics of a cationic dye, methylene blue, onto clay from aqueous solution with respect to the initial dye concentration, temperature, pH, mixing rate and sorbent dosage were investigated. In order to understand the adsorption mechanism in detail, zeta potentials and the conductivities of clay suspensions at various pH (1-11) and cation exchange capacity (CEC) were measured. Porosity and BET surface area of clay studied were determined. The results showed that the adsorption has been reached to equilibrium in 1 h. It was found that the amount adsorbed of methylene blue increases with decreasing temperature and also with increasing both sorbent dosage and increasing initial dye concentration. Adsorption capacity decreases with increasing pH, except for the natural pH (5.6) of clay suspensions. The adsorption kinetics of methylene blue has been studied in terms of pseudo-first-order, pseudo-second-order sorption and intraparticle diffusion processes thus comparing chemical sorption and diffusion sorption processes. It was found that the pseudo-second-order mechanism is predominant and the overall rate of the dye adsorption process appears to be controlled by the more than one-step.

Adsorption↗
PubMed2005

Adsorptive removal of phosphate from aqueous solutions using raw and calcinated dolomite.

This study explored the feasibility of utilizing raw and calcinated dolomite under CO2 atmosphere for phosphate removal in laboratory experiments. The experimental work emphasized the evaluation of phosphate adsorption characteristics of this adsorbent material. Studies were conducted to delineate the effect of contact time, initial phosphate concentration, temperature, pH, stirring speed, adsorbent dose and calcination temperature. Phosphate removal decreased with increasing temperature and slightly increased with increasing of pH. The observed decrease in the adsorption capacity with increase of the temperature from 20 to 40 and to 60 degrees C indicates that the low temperatures favor the phosphate removal by adsorption onto dolomite. Phosphate removal was seen to decrease with increasing calcination temperature due to the structural changes occurring in the structure and pore size distribution of dolomite samples during calcination. The experimental data obtained were applied to the Freundlich, Langmuir, BET, Halsey, Harkins-Jura, Smith and Henderson isotherm equations to test the fit of these equations to raw and calcinated dolomite samples. By considering the experimental results and adsorption models applied in this study, it can be concluded that adsorption of phosphate occurs predominantly through physical interactions, and the dolomite sample has a heteroporous structure. The large values of the constants for Henderson equation and the high value of y(m) obtained from BET equation indicate the microporous structure is more stable in raw and calcinated dolomite samples.

Adsorption↗
PubMed2005

The coincidence of mediastinal tuberculosis lymphadenitis in lung cancer patients.

Mediastinal lymph node enlargement in operable non-small cell lung cancer is of clinical importance since it indicates the high possibility of nodal metastasis. The coincidence of tuberculosis and lung cancer is detected by the mediastinal lymph node staging of lung cancer patients. In our study, we retrospectively re-evaluated the records of patients who had been hospitalized with the diagnosis of lung cancer for the past 10 years. The mean age was 58 +/- 10 years (ranging from 39 to 72). A tuberculous lymphadenitis was detected in 16 of the 315 (5.1%) patients in one and/or multiple stations by either mediastinoscopy or thoracotomy. Inferior paratracheal lymph nodes (4R-4L) were the most frequently affected. None of the patients had a history of primary tuberculosis infection. The cell type was squamous cell carcinoma in ten patients (62.5%) and adenocarcinoma in six patients (37.5%). The tumour was located in the right lung in nine patients (56.2%). The most frequently involved site was the right upper lobe (n = 13, 81.2%). N2 disease was detected in six patients (37.5%). Our study showed that 5.1% of lung patients had tuberculous lymphadenitis coincidentally. The diagnosis and treatment of this latent disease could be considered as important, especially in lung cancer patients who would potentially receive radiotherapy or chemotherapy which alters the immune system. However, the real value of this finding needs further study.

Adenocarcinoma↗
PubMed2004

Kinetic modeling of liquid-phase adsorption of phosphate on dolomite.

The adsorption of phosphate from aqueous solution on dolomite was investigated at 20 and 40 degrees C in terms of pseudo-second-order mechanism for chemical adsorption as well as an intraparticle diffusion mechanism process. Adsorption was changed with increased contact time, initial phosphate concentration, temperature, solution pH. A pseudo-second-order model and intraparticle diffusion model have been developed to predict the rate constants of adsorption and equilibrium capacities. The activation energy of adsorption can be evaluated using the pseudo-second-order rate constants. The adsorption of phosphate onto dolomite are an exothermically activated process. A relatively low activation energy and a model highly fitting to intraparticle diffusion suggest that the adsorption of phosphate by dolomite may involve not only physical but also chemisorption. This was likely due to its combined control of chemisorption and intraparticle diffusion. However, for phosphate/dolomite system chemical reaction is important and significant in the rate-controlling step, and for the adsorption of phosphate onto dolomite the pseudo-second-order chemical reaction kinetics provides the best correlation of the experimental data.

Adsorption↗
PubMed2004

Determination of adsorptive properties of clay/water system: methylene blue sorption.

In this study, adsorption of methylene blue onto clay was investigated. The effect of adsorption time and temperature on the adsorption process was studied. To reveal the adsorptive characteristics of the clay studied, porosity and BET surface area measurements were made. It was observed that the adsorption capacity decreases with increasing temperature, and adsorption equilibrium was attained within 1 h. It was found that the data fit well to Langmuir, Halsey, Henderson, and Harkins-Jura models but experimental data deviate significantly from BET and Freundlich models at especially high concentrations. Furthermore, isosteric adsorption enthalpy and entropy are calculated as -7.99 kJ mol(-1) and 25.41 JK(-1)mol(-1), respectively.

Journal Article↗
PubMed2004

Simultaneous bilateral spontaneous pneumothorax report of 12 cases and review of the literature.

Simultaneous bilateral spontaneous pneumothorax (SBSP) is a very rare condition, mainly seen in patients with underlying lung disease. Up to now, there are 65 patients who have been published. Twelve consecutive patients who presented with SBSP as definitive diagnosis were recruited for this study. They represented 1 % of all patients with spontaneous pneumothorax. All patients had immediate bilateral chest tubes on admission. Five of the 12 patients (42%) had no underlying lung disease. In 7 patients, SBSP was secondary to pulmonary metastases, histiocytosis X, undefined interstitial pulmonary disease, tuberculosis, pneumonia and chronic obstructive pulmonary disease. None of the patients died during hospitalization. Eleven patients were treated with chemical pleurodesis, whereas thoracotomy and pleurectomy were necessary in 7 patients. Reexpansion of the lungs was achieved in all patients. Immediate bilateral chest tube insertion and pleurodesis are of major importance in the treatment of SBSP although a subset of patients needed surgical pleurectomy. Combination of these treatments provides successful and uneventful treatment of the disease.

Adolescent↗
PubMed2003

Chylothorax: a complication following lung resection in patients with NSCLC - chylothorax following lung resection.

BACKGROUND: Chylothorax following lung resection is not as rare as a postoperative complication as previously reported due to systematic lymph node dissection in patients undergoing lung resection for NSCLC. METHODS: We retrospectively reviewed our cases that had undergone lung resection for NSCLC and investigated the frequency and outcome of chylothorax in these patients. The factors investigated were the site and type resection, technique of systematic lymph node dissection, tumour histology and disease stage. RESULTS: Seven of 673 patients that had undergone lung resection were complicated by chylothorax (1.04 %), following lobectomy in 5 (1.28 %) and pneumonectomy in 2 (0.7 %) (p = 0.36). The fistula closed spontaneously in 5 patients between 4 - 17 days postoperatively (71 %). One of the patients in the conservative management group died on the 28th day postoperatively due to pneumonia (14 %). The remaining 2 patients underwent rethoracotomy on the 5th and 6th days. CONCLUSIONS: These results suggest that the site of operation, type resection, and technique of systematic nodal dissection, tumour histology and disease stage do not influence the development of chylothorax in patients with NSCLC. The chylous fistula following lung resection for NSCLC tends to close spontaneously.

Adenocarcinoma↗
PubMed2002

The removal of Cu(II) from aqueous solutions by Ulothrix zonata.

In this work, adsorption of copper(II) ions on alga has been studied by using batch adsorption techniques. The equilibrium biosorption level was determined as a function of contact time at several initial metal ion concentrations. The effect of adsorbent concentration on the amount adsorbed was also investigated. The experimental adsorption data were fitted to the Langmuir adsorption model. The free energy change (deltaG0) for the adsorption process was found to be -12.60 kJ/mol. The results indicated that the biomass of Ulothrix zonata is a suitable biosorbent for both the removal and recovery of heavy metals from wastewater.

Adsorption↗
PubMed2002

The value of mediastinoscopy in preoperative evaluation of mediastinal involvement in non-small-cell lung cancer patients with clinical NO disease.

BACKGROUND: The efficacy of mediastinal lymph node examination using cervical mediastinoscopy in operable non-small cell lung cancer patients without radiological nodal involvement on computerized tomography (CT) has been elusive. METHODS: The value of mediastinoscopy as a staging modality for assessing the mediastinal lymph node status was evaluated in 79 patients with presumed resectable non-small-cell lung cancer (NSCLC) with mediastinal nodes smaller than 1 cm (NO) form the CT scan. Sixty-one patients who did not have nodal involvement at mediastinoscopy and had complete medical records underwent complete resection. RESULTS: Negative predictive value (NPV) of the CT scan according to mediastinoscopy was 92.4 %. Histopathological examination of the surgical specimen showed the NPV of mediastinoscopy to be 93.4 %. Only 4 patients (3 patients with N2, 1 patient with N3 disease) were not correctly staged using CT scanning and mediastinoscopy. According to the pathological examination, the NPV of CT was found to be lower (76.5 %) in patients with adenocarcinoma, but the difference was not statistically significant (p > 0.128) CONCLUSION: Although the likelihood of surgical-pathological N2 is slightly higher in patients with adenocarcinoma, radiological examination of patients with cNO NSCLC disease can be as accurate as mediastinoscopy in appropriately staging mediastinal lymph node involvement.

Adult↗
PubMed1991

Exercise testing in children with congenital heart disease before and after surgical treatment.

Pre- and postoperative exercise tests were performed on 12 children with severe congenital heart disease (CHD) (age, 4-12 years). Oxygen uptake, blood pressure, and heart rate responses to exercise were measured. Exercise test time and the tolerable speed of the treadmill increased significantly after the operation. When pre- and postoperative values were compared, exercise heart rates did not change in most of the children, while delta systolic blood pressure rose significantly. The significant increase in peak oxygen consumption (VO2/Kg) values also revealed that there was an improvement in their exercise capacity after the operation.

Blood Pressure↗
PubMedDate not supplied

Emergency surgery for massive haemoptysis.

BACKGROUND: Massive haemoptysis (600 ml in 24 hours) results in considerable mortality and deserves appropriate management. Since it is life threatening, lung resection remains the surgical treatment of choice in unrelenting haemoptysis. MATERIAL AND METHODS: We retrospectively reviewed all patients (n = 29) who were referred to our clinic between January 1994 to September 2001 with massive haemoptysis (> 600 ml/24 h). All patients had uncontrollable haemorrhage and/or failure of conservative treatment. After initial resuscitation, assuring adequate airway and providing adequate intravenous access, emergency thoracotomy was performed in all patients following rigid bronchoscopy (n = 27) in order to localize the bleeding. RESULTS: The most common underlying cause of the massive haemoptysis was pulmonary tuberculosis (n = 10) followed by emphysema in 4, lung cancer in 3, collagenous vascular disease in 2 and aspergilloma in one patient. Seventeen lobectomies (58.6%), 5 pneumonectomies (17.2%), 3 segmentectomies and 3 bilobectomies were done whereas physiological lung exclusion was performed in one patient. Haemoptysis could be controlled in all patients. Rate of operative morbidity and hospital mortality were 27.5% and 11.5% respectively. We recorded one patient with recurrent haemoptysis who was treated by completion pneumonectomy. CONCLUSION: Despite the debate over definition of massive haemoptysis and indication for surgery in these patients, emergency pulmonary resection provides an effective treatment with acceptable morbidity and mortality in patients with massive haemoptysis.

Aspergillosis↗