Showing papers by "Celal Bayar University published in 1998"

Comparisons of tin depth profile analyses in float glass

Abstract: Data are presented showing the profile of tin diffusion during the production of float glass, by measuring non-destructively the refractive index profiles in the diffused layer. The optical waveguide modes give unequivocal evidence for an anomaly in the tin depth distribution. The results are compared with those from sectioning techniques, used in depth profiles determined by ion beam analyses and cathodoluminescence (CL). There is agreement between these methods which confirm the presence of a maximum in the tin concentration below the surface which had been in contact with the tin bath (this had been linked by Mossbauer data to a rise in the Sn 4+ concentration). The ion beam analyses record different depth profiles for Si, Na and Ca. The Sn 4+ feature increases the refractive index, as does the diffusion of Sn 2+ . The index becomes constant at large tin concentrations. We suggest that Sn 4+ is linked to CL emission at 2.68 eV and Sn 2+ to the 1.97 eV CL emission. Iron impurities give a 1.73 eV signal. Contrary to earlier suggestions, we propose that the luminescence associated with the presence of tin arises from intrinsic defects stabilised by the tin, not from tin acting directly as a luminescence site.

Evaluation of intraocular pressure and cataract formation following the long-term use of nasal corticosteroids

Abstract: It is possible that corticosteroids administered via nasal spray might reach ocular structures in levels sufficient to provoke an ocular hypertensive response and cause posterior subcapsular cataracts (PSCs) in susceptible individuals. In the present study, 26 patients who had undergone endoscopic sinus surgery were evaluated prospectively with respect to intraocular pressure and PSC formation following the use of nasal steroids for at least three months. Eighteen patients (69%) self-administered 200 micrograms/day of budesonide nasal spray twice daily, and eight patients (31%) self-administered 200 micrograms/day of beclomethasone dipropionate nasal spray twice daily, for a period of three to 19 months (mean 8.8 +/- 3.6 months). Ophthalmologic examination, tonometry, visual field testing and biomicroscopic studies revealed no evidence of ocular hypertension or PSCs during postoperative follow-up. We conclude that intranasal corticosteroids can be used safely for prolonged periods without increasing the risk of ocular hypertension or PSCs.

Heavy metal bioaccumulation by cultivated Agaricus bisporus from artificially enriched substrates

Abstract: Cultivated Agaricus bisporus possess the ability to bioaccumulate seven heavy metals (Pb, Cd, Hg, Fe, Cu, Mn, and Zn). The cultivated champignon mushroom A. bisporus was grown in soil composts of 16 different compositions. An edible mushroom, A. bisporus was also cultivated on humic compost artificially fortified with the seven heavy metals at five different concentrations (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10.0 mg/kg) and on control substrate (0 mg/kg) on a dry weight basis. The method of measuring bioaccumulation was flame atomic absorption spectrophotometry.

The influence of religious fasting on basal tear secretion and tear break-up time

Abstract: Muslims abstain from food and drink from dawn to sunset during the holy month of Ramadan. An extended strict fasting may influence tear secretion and quality. We investigated changes in basal tear secretion (BTS) and tear break-up time (BUT) at the beginning and at the end of fasting on 32 healthy male patients with a mean age of 22.3 ± 2.9 years. Body weight and urine specific gravity were also determined to assess the extent of dehydration due to fasting. Each case lost 0.1–1.25 kg of body weight while urine specific gravity changes were statistically insignificant. Mean BTS amount was 19.9 ± 10.9 mm at the initial examination and 19.7 ± 11.5 mm at the end of fasting (p=0.9). BUT values were 20.1 ± 9.3 sec at the beginning of fasting and 23.5 ± 14.9 sec at the end of fasting (p=0.19). We found that religious fasting in the winter season does not seem to affect BTS and BUT values in healthy individuals.

Changes in pattern reversal evoked potentials during menstrual cycle.

Abstract: Hormonal changes that occur during the menstrual cycle of women influence the visual function of females. Estrogen is reported to cause a decrease in the visual transmission time by increasing the sensitivity of receptors in the optic pathways to dopamine. The aim of this study was to search if pattern reversal evoked potentials (PRVEPs) changed during the different phases of the menstrual cycle. PRVEPs of both eyes of 30 healthy women were recorded in 4 different phases of the menstrual cycle, namely, menstrual, follicular, ovulatory and luteal. The highest mean PRVEP latency and the lowest mean P100 amplitude were recorded during the menstrual phase. The mean PRVEP latency recorded during the ovulatory phase (when estrogen level rises to 3-5 times that of other phases' without an increase in progesterone levels) was statistically significantly shorter than that of other phases' (p<0.05). Although not statistically significant, the mean P100 amplitude recorded during the ovulatory phase was higher than the other phases. Looking at these results, sex steroids seemed to affect the generation of PRVEPs. The significant decrease in PRVEP latencies when estrogen levels peaked was thought to be due to facilitating effect of estrogen on the neural transmission of the visual pathways.

Effect of long-term alcohol abuse on male sexual function and serum gonadal hormone levels.

Abstract: Purpose The relationship between chronic alcohol abuse and male sexual dysfunction and pituitary gonadal function abnormalities remains uncertain. The purpose of this study was to assess the effect of chronic alcoholism on sexual functions and serum hormone levels.

Mechanical properties and wear strengths in aluminium-alumina composites

Abstract: In this study, after producing metal matrix composite materials reinforced with ceramic particles by adding hard Al2O3 particles into a selected ageable aluminum alloy, the wear strengths were investigated. Composites of aluminum alloys containing 2 to 10 wt of Al2O3 particles in the size range of 23.4 to 108 μm were prepared by adding alumina particles to a partially-solid vigorously-agitated matrix alloy. For a given tribologic system, the sizes and ratios of optimum particles were determined from the point of the wear strengths of these materials, of which the wear strengths greatly increased according to the matrix materials. Alumina particles were subjected to preheating at 500°C for 8 hours. Particles were added into the alumina alloy heated up to semi-solid/semi-liquid phase interval in an argon medium by using a mixer. Then furnace temperature was raised up to 800°C step by step. Later the composite materials were die cast and solidified and aged. The behavior of the composites was studied by using a pin-on-disk type machine. The largest wear strengths were obtained at an average particle size of 76.5 μm and percentage of 4% wt Al2O3. Increase in the wear strength of the composites was obtained as 3.85 times the wear strength of the matrix material.

Analyses of boronic ores and sludges and solubilities of boron minerals in CO2-saturated water

Abstract: In this study, the potential of boron in Turkey, commercial most-used compounds of boron and their production trends according to years and analyses of boronic samples obtained different sources were investigated. Besides classic analysis technics, X-ray fluorescence spectrometric (XRF) and flame photometric methods were carried out for boronic samples. Chemical compositions of original and concentrated samples were studied with respect to the contents of B, Li, Ca, Al, Fe, Mg, S, As, Si, Sr and Na. The leaching of boric acid with CO 2 -saturated water from boron minerals was also investigated.

Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy

Abstract: Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A 56-year-old woman with mild dry-eye symptoms developed keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted for less than 1 day in the upper keratotomy incision. Corneal cultures yielded Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the detection of keratitis. The inflammation was controlled with intravitreal, subconjunctival, topical, and systemic antibiotics. This case demonstrates the potential risk of endophthalmitis developing very shortly after late keratitis of AK incisions. Vigorous, early treatment and close follow-up seem justifiable in any keratitis associated with a keratotomy incision.

Effect of Vitamin E on Vascular Responses of Thoracic Aorta in Rat Experimental Arthritis

Abstract: 1. Vascular contractile and relaxant responses were evaluated in isolated aortic rings of adjuvant-induced arthritic rats in comparison with control rats, and the effect of an antioxidant treatment on the development of the arthritis was investigated by vitamin E administration (100 mg/kg/day, i.m., for 26 days). 2. Arthritis was induced by an intradermal injection of Freund's complete adjuvant into rat paw. Vascular responses, arthritic lesions and serum copper levels were evaluated after 26 days from adjuvant inoculation. 3. Serum copper levels were significantly lower in arthritic rats than in the control. 4. The contractile response of aortic rings to phenylephrine (PE), but not to KCl, was increased in preparations from arthritic rats, which could be explained by an enhancement of intracellular calcium contents. 5. Acetylcholine (Ach)-mediated endothelium-dependent and sodium nitroprusside (SNP)-mediated endothelium-independent relaxations were not changed significantly in vascular preparations from arthritic rats. 6. In arthritic rats, vitamin E treatment improved arthritic lesions with an increase in copper levels. Despite this ameliorating effect, vitamin E treatment caused an increase in contractile response to PE and a decrease in the relaxant response to Ach and SNP in arthritic rats. 7. These data show that vitamin E provides ameliorating effects in improving systemic signs of experimental arthritis, but it fails to restore abnormalities in vascular function, indicating that adjuvant-induced alterations in vascular function may include mechanisms other than oxygen-free radical formation.

Evaluation of voice and speech following subtotal reconstructive laryngectomy

Abstract: Subtotal reconstructive laryngectomy (SRL) can be used to preserve voice in the treatment of selected laryngeal carcinomas. This study was designed to analyze both voice and speech results achieved after SRL in 14 male patients, aged from 48 to 73 years. Surgery was performed between 1983 and 1993. Fundamental frequencies, ranges of frequency, intensities, and intensity ranges were established using an S.I. 80 Philips AAC 600 Audio Active Comparative Language System. Five prolonged vowels and six phonetically balanced sentences were recorded on a tape positioned at a distance of 30 cm from the mouth of each patient during a 3-min recording time. The recorded material was then evaluated by a panel of ten trained listeners who were asked to consider the qualitative parameters and perceptual characteristics of voice and speech according to a scorecard modified from one devised by Voiers and Formigoni. Although a decrease was determined in Fundamental Frequency and intensity of the voice when compared to normal values, the quality and perception of speech were found to be satisfactory. The verbal message could be understood almost exactly by means of constant sonority, correct articulation and improved pneumophonic coordination. These values demonstrate that the new voice achieved after SRL is less sonorous and allows for understandable and socially acceptable speech.

Recurrent Interstitial Pregnancy

Abstract: Summary: As a rare form of ectopic pregnancy, interstitial pregnancy threatens the future fertility of the patient. Methods of management include observation only, medical treatment with methotrexate either systemically or locally, or surgery either with laparotomy or laparoscopy. We present the case of a woman with recurrent interstitial pregnancy. Treatment with methotrexate was successful in her first interstitial pregnancy, however the second necessitated laparotomy. Selection of patients for treatment with methotrexate and the importance of subsequent tubal investigation are emphasized.

A large family with type IV radial polydactyly.

Abstract: This study examines one of the largest pedigrees with radial polydactyly type IV (uncomplicated polysyndactyly) comprising a total of 69 individuals, of whom 26 have been affected over six generations. Typical manifestations of the pedigree were bilateral radial and ulnar digital duplications, as well as syndactyly between the middle and ring fingers and the second and third toes. There was no craniofacial anomaly in any of the 17 cases examined physically. This observation suggests that radial polydactyly type IV and Greig craniofacial-synostosis syndrome with similar digital manifestations are clinically-distinct entities.

Possible Contribution of Leukotrienes in the Arrhythmogenic Effects of Digoxin on Isolated Guinea-Pig Hearts

Abstract: The effect of a leukotriene D4 (LTD4) receptor antagonist, L-648,051, was investigated in digoxin-induced cardiac toxicity in isolated guinea-pig hearts (Langendorff preparation). Digoxin infusion (25 µg·ml–1, 0.5 ml·min–1) increased perfusion pressure and contractile force initially, but decreased them later. The onset of first ventricular premature beats (VPBs) matched the increase phase, but the decrease phase was accompanied by ventricular tachycardia (VT) and fibrillation (VF). In the presence of L-648,051 (5 µmol·l–1), the initial phase was similar to that observed with digoxin alone, but the marked reduction was inhibited. This drug increased the concentration of digoxin required for VBSs and cardiac arrest, but it could not prevent the formation of VT and VF. The duration of VT was significantly decreased by L-648,051. It is concluded that the leukotriene receptor antagonist might have beneficial effects on digoxin-induced arrhythmias. Whether this effect depends on direct or indirect actions is uncertain.

Askin tumors in children : A report of four cases

Abstract: Primary malignant tumors of the chest are rare in the pediatric age group. Askin tumor belongs to the peripheral primitive neuroectodermal tumor family, and typically involves the periosteum, soft tissue and extrapulmonary tissue of the thoracic wall. We report our ten years experience with four cases of this rare tumor.

Environmental exposure to cadmium and lead in the pediatric age group

Abstract: Lead additives in automotive fuel, smog from a nearby industrial center warranted an investigation on cadmium and lead in Manisa, a city of tabacco processing. Hundred and one children were screened in view of lead and cadmium exposure. In 23 children between the ages of 0–2 years the mean (±SEM) serum lead level was 7.15 ± 0.10 μg/dl, in 28 between the ages of 3–6 years was 7.20 ± 0.10 μg/dl and in 50 between the ages of 7–15 years was 7.20 ± 0.10 μg/dl, respectively, with no significant differences. Serum cadmium levels in the same groups of children was 0.066 ± 0.008 ng/ml, 0.078 ± 0.008 ng/ml 0.088 ± 0.006 ng/ml, respectively. The difference in cadmium levels between the age groups of 0–2 years and 7–15 years was significant (p<0.038). This significant increase in blood cadmium level is also shown by simple linear regression analysis: Cadmium (ng/ml) = 0.049 + 0.005 (age), and p<0.0001, F Ratio = 50.578, coefficient of correlation = 0.581. Our study revealed that lead is not a serious environmental contaminant for children, yet; however, the increasing trend seen in exposure to cadmium warrants serious consideration and urgant preventive measures.

Analysis of power losses in energy transmission systems including linear load by using artificial neural networks

Abstract: This paper presents the application of artificial neural networks (ANN) for analysis of power losses in an energy transmission network. Problem formulation and design of ANN for loss analysis is described. Due to the capability of parallel information processing of the ANN, the proposed method is fast and yet accurate. Active and reactive powers of generators and loads, as well as the magnitudes of voltages at voltage-controlled buses are chosen as inputs to the ANN. System power losses are chosen as the outputs. Training data are obtained by load flow studies. Load flow studies for different system topologies are carried out and the results are compiled to form the training set. Numerical results are presented in the study to demonstrate the effectiveness of the proposed algorithm in terms of accuracy and speed.

The effects of extensive vas mobilization on testicular histology during orchiopexy.

Abstract: We were aware that extensive mobilization of vas deferens during orchiopexy could cause secondary infertility due to testicular damage and/or functional obstruction of the vas deferens. We decided to perform this experimental study in order to document the effects of this procedure on the testis. Thirty adult fertility-proven New Zealand white rabbits were randomly divided into 3 groups. Ten rabits underwent extensive mobilization of the vas deferens and the other 10 rabbits had vasectomy on the left side. The remaining 10 rabits were explored on the left side only and were considered sham controls. Four weeks later all rabbits underwent bilateral orchiectomy. Mean seminiferous tubular diameters and Johnsen's testicular biopsy scores were noted. Comparison of the three groups showed that vas mobilization and vasectomies cause no effect on the viability of testis, however, significant testicular histological changes, which were different from the controls and contralateral testis, were observed. We concluded that during any surgical intervention involving the inguinal canal, vascular and neural supports of the vas deferens should be preserved as much as possible in order to avoid iatrogenic damages to the testis.