Scopus Koleksiyonu

Permanent URI for this collection

http://akademikarsiv.cbu.edu.tr:4000/handle/123456789/1458

Browse

Now showing 1 - 20 of 9443

Luminescence of levitated Zr-Ba-La-Al-Na fluoride glass
(1997) Yang B.; Townsend P.; Can N.
Radioluminescence, cathodoluminescence, and thermoluminescence of Zr-Ba-La-Al-Na (ZBLAN) fluoride glass reveal different aspects of the intrinsic imperfections and impurities which control the emission. Except for weak low-temperature thermoluminescence signals which could be attributed to rare-earth impurities, the majority of the emission bands were common to all samples. These are considered to arise from intrinsic electron-hole recombination processes, either during relaxed exciton emission or at intrinsic defect sites in the glass network. Deconvolution of the spectra indicates that six emission bands occur in all the samples. Production of crystallite inclusions or intrinsic defects enhance the signal intensities. The luminescence is shown to be a useful probe of the quality of the ZBLAN glass, both in the preform stage, and after fiber drawing, even when working with the very high grade material produced by gas film levitation growth. © 1997 The American Physical Society.
The effect of zinc supplementation in experimentally induced Toxoplasma gondii infection.
(1995) Tasçi S.; Sengil A.Z.; Altindis M.; Arisoy K.
The effect of zinc added diet on cellular immunity in toxoplasmosis was investigated on 50 male wistar albino rats. Total lymphocyte CB8 count were found higher in the infected group when compared to the control group (P < 0.001). The relative increase of CD8 was found to be responsible for the decrease in ratio. In the infected group, there was a slight decrease in CD4 count but it was statistically insignificant. While no significant differences in serum zinc level were observed between the groups, there was a positive correlation with CD8 count in infected group (r = 0.005, P < 0.05). As a result, zinc added diet in toxoplasmosis stimulated the cellular immunity, increased CD8 and total lymphocytes.
Computer-aided design of submarine pipelines
(1995) Gökkus Ü.
The computerization of pipeline design is relatively important for the engineering feasibility of submarine pipelines. The changing environmental conditions make difficulties for the stability calculation of each pipe segment on line. For this reason, the computer study will provide many advantages during the design of pipeline. The different environmental and functional parameters can be easily tried on line and the most suitable size of structure against the extreme environmental conditions can be determined. This study deals with the general design principles especially including the engineering studies, i.e. wave statistical analysis, transformation of waves, stability analysis, and developed computer program to achieve both the stabilization of pipeline and aid for drawing the route together with user in some stages of the design. Finally, the outline of the program is briefly described and a flow chart is presented. © 1995, International Association on Water Quality. All rights reserved.
The optimisation of the dissolution of phosphate rock with Cl2-SO2 gas mixtures in aqueous medium
(Elsevier, 1997) Abali Y.; Çolak S.; Yapici S.
In the present study, aimed at the production of phosphate compounds, the optimum process conditions were sought for the dissolution of phosphate rock from the Mardin-Mazidaǧi concentrate. The dissolution of this phosphate rock in aqueous solution saturated with a mixture of Cl2-SO2 gases was optimized by passing Cl2 gas through the final solution. Reaction temperature, solid-liquid ratio, Cl2 gas flow rate, reaction period and stirring speed were employed as parameters. Using the Taguchi Fractional Design Method, it was found that the optimum process conditions, at which 93.35% P2O5 conversion was reached, were as follows: Reaction temperature: 20°C Solid-liquid ratio: 1/7 (w/v) Cl2 gas flow rate: 120 cm3 min-1 Reaction period: 20 min Stirring speed: 600min-1.
Nonlinear vibrations of a beam-spring-mass system
(1994) Pakdemirli M.; Nayfeh A.H.
The nonlinear response of a simply supported beam with an attached spring-mass system to a primary resonance is investigated, taking into account the effects of beam midplane stretching and damping. The spring-mass system has also a cubic nonlinearity. The response is found by using two different perturbation approaches. In the first approach, the method of multiple scales is applied directly to the nonlinear partial differential equations and boundary conditions. In the second approach, the Lagrangian is averaged over the fast time scale, and then the equations governing the modulation of the amplitude and phase are obtained as the Euler-Lagrange equations of the averaged Lagrangian. It is shown that the frequency-response and force-response curves depend on the midplane stretching and the parameters of the spring-mass system. The relative importance of these effects depends on the parameters and location of the spring-mass system. © 1994 ASME.
A new experimental in vitro culture medium for cultivation of Leishmania species
(American Society for Microbiology, 1997) Limoncu M.E.; Balcioglu I.C.; Yereli K.; Ozbel Y.; Ozbilgin A.
A new liquid culture medium prepared with chemicals that can be obtained economically and commercially was tested in in vitro cultivation of Leishmania promastigotes to obtain a large number of organisms to use in serological studies. The number of Leishmania infantum and Leishmania tropica promastigotes taken from Novy-MacNeal-Nicolle (NNN) medium reached 1 x 107/ml at the end of the 8th day in our new medium, though in NNN medium the number of organisms reached only 5 x 106/ml. After 10 subsequent passages, the culture medium prepared was evaluated as being quite inexpensive, simple, and successful compared with other commercially available liquid culture media.
The electrocardiogram of the Pekin duck
(American Association of Avian Pathologists, 1996) Cinar A.; Bagci C.; Belge F.; Uzun M.
In this study, standard limb lead electrocardiograms (ECG) were recorded in 50 Pekin ducks. The ECG exhibited P, R, S, and T waves. A Q wave was observed in 30% of leads aVR aVL. All waves in lead I were of very low amplitude or almost isoelectric. The P wave was 20% negative, 80% positive in lead aVR and always positive in other leads. The duration and amplitude of P wave were 0.025 sec and 0.17 mV, respectively, and the P-R interval was 0.06 sec in lead II. A Q wave was observed in 30% of leads aVR and aVL but was invisible in other leads. The duration of QRS complex was 0.036 sec and its amplitude was 0.069 mV. The S wave (rS) was greater than the R wave in leads III and aVF. The R and S waves were equal in lead III (66%). The mean duration and amplitude oft wave were 0.05 sec and 0.22 mV, respectively. The T wave was negative in leads aVR and aVL and positive in other leads. The Q- T interval was 0.10 sec. The mean heart rate was 281.3 (220-375) beats/min. The average value of the mean electrical axis was +147°(+95°to -160°).
The proximate composition and some minor constituents of poppy seeds
(1994) Nergiz C.; Ötles S.
The proximate chemical composition of poppy seeds, along with minerals and water‐soluble vitamins content was investigated. The compositions of the fatty acids and tocopherols of the extracted oil were also determined. The proximate analysis of poppy seeds showed the following composition: (440 g kg−1), protein (211 g kg−1), moisture (50 g kg−1), ash (63 g kg−1), crude fine (62 g kg−1) and total carbohydrates (236 g kg−1). Potassium and calcium were the predominant elements in the poppy seeds. Linoleic acid was the major unsaturated fatty acid (750 g kg−1 total fatty acids) while palmitic acid was the main saturated one (86‐4 g kg−1). The amounts of α‐, β‐ and δ‐tocopherols found in poppy seed oil were 220 μg g−1, 40 μg g−1 and 20 μg g−1 respectively. Among the water‐soluble vitamins determined, pantothenic acid was found at the highest level followed by niacin and thiamin. Copyright © 1994 John Wiley & Sons, Ltd
The effect of tramadol on minimal alveolar enflurane concentrations in children; [TRAMADOL'UN COCUKLARDA MINIMAL ALVEOLER ENFLURAN KONSANTRASYONLARINA ETKISI]
(1996) Erincler T.
Laryngospasm following extubation can be quite troublesome after adenoidectomy and tonsillectomy for children. High end-tidal anesthetic concentrations may prevent the anesthetized patients from coughing or moving during and immediately after tracheal extubation, but extubating while the child is quite deeply anesthetized is uncommon in current practice. In this study it has been proved that tramadol given intravenously at a dose of 2 mg/kg following extubation is quite effective in preventing laryngospasm in children after adenoidectomy, and does not cause respiratory depression. Eighty-seven children undergoing adenoidectomy and myringotomy were divided randomly into two groups consisting of 33 and 54 children. Tramadol was given intravenously after the induction of anesthesia to the larger group. Anesthesia was maintained with enflurane, nitrous oxide and oxygen in both groups. End-tidal enflurane concentrations were sampled from a -T- piece attached to the endotracheal tube and measured continuously by mass spectrometry. Oxygen saturations were monitored by pulse oximetry. The minimum alveolar concentrations of enflurane for satisfactory tracheal extubation were found to be 1.9 ± 0.5% and 0.8 ± 0.4% in group I and group II children, respectively. In anesthetized children between ages 2 and 9, tracheal extubation may be accomplished without coughing, laryngospasm or respiratory depression with smaller end-tidal enflurane concentrations, if tramadol is administered previously.
P-36 Antidepressant choice in the outpatient department of a psychiatry clinic
(Elsevier B.V., 1996) Işelli I.; Özmen E.
[No abstract available]
EMG pattern discrimination for patient-response control of FES in paraplegics for walker supported using artificial neural network (ANN)
(IEEE, 1996) Kocyigit Yucel; Karlik Bekir; Korurek Mehmet
FES (functional electrical stimulation) encompasses the use of electricity in functioning neural substrates. FES is used to restore lower limb function to individuals paralyzed by spinal cord injury. The system determines a patient-responsive manner using above-lesion surface EMG signals to activate standing and walking functions. In this work, classification of EMG patterns which were used by FES to restore lower limb function of walker-supported walking patients was done by using ANN.
The effects of sterile or infected bile and dropped gallstones in abdominal adhesions and abscess formation
(Springer New York, 1997) Soybir G.R.; Köksoy F.; Polat C.; Özşeker A.; Yalçln O.; Aker Y.; Topuzlu C.
Background: The effects of gallstones and sterile or infected bile on postoperative adhesions and abscess formation were investigated in Sprague Dawley rats. Methods: The first three groups were injected intraperitoneally with serum saline, sterile bile, or infected bile, respectively. Laparotomy was adjusted to the next seven groups. Serum saline, sterile bile, and infected bile were injected in the fourth through sixth groups intraperitoneally, respectively. Gallstones were placed intraabdominally to the seventh through ninth groups. The injections of sterile bile in group 7 and of infected bile in group 8 were added to laparotomies. Only laparotomy was carried out in group 10. Results: Abscess formations were seen only in infected-bile-injected groups. Significant adhesion formations were seen in infected-bile groups. Sterile bile and/or gallstones had no significant effect in abscess or adhesion formation. Conclusions: Results suggest that noninfected gallstones and sterile bile, even in combination, do not increase post-operative intraabdominal complications in rats.
Zinc tolerance test patterns in normal children and in moderate and severe zinc deficiency states
(Springer India, 1996) Oksel F.; Köksyo H.; Taneli B.
Twenty-six normal, 38 moderately and 14 severely zinc-deficient children, aged 2-12 years, were examined by clinical and laboratory approaches. After fasting-blood sampling, 120 mg zinc sulphate (25 mg elemental zinc) were administered orally to each group of children, to obtain zinc tolerance curve patterns. Sampling proceeded to the 2nd and 4th hours of the loading test period. Plasma zinc was assessed on an atomic absorption spectrophotometer. In normal children, at the 2nd hour of loading, a significant (p < .001) elevation (1.764 ± 0.133 mg/l) in the mean (±SEM) plasma zinc level was noted; also at the 4th hour a significant (p < .001) decrease (1.506 ± 0.123 mg/l) in the mean plasma zinc level was shown. The mean plasma zinc level at the 4th hour was found higher than the mean fasting plasma zinc level (1.054 ± 0.061 mg/l), but lower than the mean level found at the 2nd hour. In moderately zinc-deficient children, tle rise in the 2nd hour and the fall in the 4th hour in the plasma zinc level were highly significant (p < .001 and p < .001, respectively) in relation to fasting blood level. However, in severely zinc deficient children, the intensity of the increase (0.746 ± 0.147 mg/l) in plasma zinc level at the 2nd hour was of lesser significance (p < .006) and the fall (0.424 ± 0.061) mg/l) at the 4th hour was not significant. Therefore, in children with normal plasma zinc levels, an increase of more than 0.50 mg/l was seen at the 2nd hour of loading. This rise was seen to persist at the 4th hour. However, in children with moderate zinc deficiency, although again an increase of 0.50 mg/l was seen at the 2nd hour this increase did not persist at the 4th hour; and the 4th-hour value showed a significant decrease in relation to the 2nd hour value. Whereas, in children with severe zinc deficiency the rise of plasma level at the 2nd hour was less than 0.5 mg/l and the fall at the 4th hour was to such a level which was not significant in relation to fasting zinc level. This could be due to enhanced uptake of zinc off the circulation by the depleted tissues in severe zinc deficiency.
Effects of extracorporeal shockwave lithotripsy at different stages of pregnancy in the rabbit
(Mary Ann Liebert Inc., 1997) Gümüş B.; Lekili M.; Kandiloǧlu A.R.; Işisaǧ A.; Temeltaş G.; Nazli O.; Büyüksu C.
Although SWL is now the most common treatment modality for urinary tract stone disease, it is not regarded as a safe method for pregnant patients because of its potential harmful effects on fetus. Using a rabbit model, we investigated whether SWL might cause fetal injury when administered at various developmental stages. Two groups of pregnant rabbits were given 1000 shockwaves either early or late in the gestational period. Time-matched controls did not receive shockwaves. After spontaneous labor, all newborn rabbits were counted, weighted, and measured, and specimens were taken from organs and examined histopathologically. The numbers, weights, and diameters of the newborns in each group were similar. There was no notable histopathologic finding in the heart and brain specimens of any of the newborns, whereas noticeable congestion and multiple focal intraparanchymal microhemorrhages were found in lungs, livers, and kidneys of the animals that had been exposed to shockwaves early in gestation. In conclusion, this study shows that SWL is not a safe treatment in early pregnancy.
Similarity analysis of boundary layer equations of a class of non-Newtonian fluids
(1994) Pakdemirli M.
A similarity analysis of three-dimensional boundary layer equations of a class of non-Newtonian fluids in which the stress is an arbitrary function of rates of strain is made. It is shown that under scaling transformation, for an arbitrary stress function, only 90° of wedge flow leads to similarity solutions, whereas for a specific more restricted form, similarity solutions exist for arbitrary wedge angles. In the case of spiral group transformation, no similarity solutions exist if we force the stress function to remain arbitrary after the transformation, whereas for a specific more restricted form, similarity solutions exist for arbitrary wedge angles. For both transformations, similarity equations for power-law and Newtonian fluids are presented as special cases of the analysis. Finally the conditions for invariance and the form of the stress function for a two-dimensional case are also presented. © 1994.
Symmetry groups of boundary layer equations of a class of non-newtonian fluids
(Elsevier Ltd, 1996) Pakdemirli M.; Yürüsoy M.; Kücükbursa A.
A non-Newtonian fluid model in which the stress is an arbitrary function of the symmetric part of the velocity gradient is considered. Symmetry groups of the two-dimensional boundary layer equations of the model are found by using exterior calculus. The complete isovector field corresponding to some cases, such as arbitrary shear function, Newtonian fluids, and power-law fluids, are found. Similarly, solutions for some special transformations are presented. Results obtained in a previous paper [M. Pakdemirli, Int. J. Non-Linear Mech. 29, 187 (1994)] using special groups of transformations (scaling, spiral) are verified in this study using a general approach. Copyright © 1996 Elsevier Science Ltd.
A comparative study of azithromycin, cephalexin and penicillin V for the treatment of streptococcal pharyngitis and tonsillitis in children; [COCUKLARDA STREPTOKOKSIK FARENJIT VE TONSILLIT TEDAVISINDE AZITROMISIN, SEFALEKSIN VE ORAL PENISILIN VNIN ETKINLIGININ KARSILASTIRILMASI]
(1996) Ece A.; Iscan A.; Sengil A.Z.; Balkan C.; Cetinkaya Z.
In this study, clinical and bacteriological efficacies of penicillin V were compared with those of azithromycin and cephalexin. Of 94 children who had group A beta hemolytic streptococcal (GABHS) pharyngitis/tonsillitis, 31 received a single daily. dose of azithromycin (10 mg/kg) for three days, 33 received cephalexin 40 mg/kg/day in three doses for 10 days, 30 received oral penicillin V 50.000 IU/kg for 10 days. At the end of the treatment, bacterial eradication was achieved in 91% of azithromycin-treated patients, 88% of cephalexin-treated patients and 83% of penicillin treated-patients (p > 0.05). Clinical cure rates were 94% in azithromycin group, 91% in cephalexin group and 90% in penicillin group (p > 0.05). At follow-up evaluation (day 30 ± 5) bacteriologic recurrence was observed in 4 patients of azithromycin-treated group (13%), in 6 of cephalexin treated group (18%) and in 6 of penicillin-treated group (20%). The results of this study indicate that oral penicillin V is clinically as effective as azithromycin and cephalexin in the treatment of GABHS pharyngotonsillitis.
Increased serum copper and decreased serum zinc levels in children with iron deficiency anemia
(Humana Press Inc., 1997) Ece A.; Uyanik B.S.; Işcan A.; Ertan P.; Yiǧitoǧlu M.R.
In order to evaluate serum copper and zinc status in children with iron deficiency anemia (IDA), 60 children with IDA aged 1-14 yr and 64 healthy children as controls aged 1-14 yr were included the study. Serum copper levels were higher in children with IDA (189 ± 49 μg/dL) than those of controls (163 ± 37 μg/dL) (p = 0.001). Serum zinc levels were lower in the patient group (109 ± 59 μg/dL) than those of control subjects (135 ± 56 μg/dL) (p = 0.017). In addition, there were statistically significant negative correlations between hematological parameters and serum copper levels in the patient group, but not in controls. No correlation between hematological parameters and serum zinc levels were found in both patient and control groups, except positive correlation between mean corpuscular volume (MCV) and serum zinc level in patients. It was concluded that at the time of managing children with IDA, zinc deficiency must be borne in mind and if necessary treatment should be initiated with zinc.
Dissolution kinetics of phosphate rock with Cl2 gas in water
(Elsevier, 1997) Abali Y.; Çolak S.; Yartaşi A.
In this study the dissolution kinetics of phosphate rock with Cl2 gas in aqueous media were investigated. The effect of particle size, solid-to-liquid ratio, gas flow rate, reaction temperature and stirring speed on the dissolution process were determined. It was observed that the dissolution of the phosphate rock increased with increasing gas flow rate and stirring speed and with decreasing particle size and solid-to-liquid ratio. Increasing reaction temperature increased the dissolution slightly between 12°C and 30°C and decreased it between 40°C and 80°C. By analysis of the experimental data using heterogeneous kinetic models it was determined that the dissolution process is controlled by diffusion through the fluid layer.
Increased lipoprotein (a) and its relationships with other parameters of lipoprotein metabolism in chronic renal failure treated by hemodialysis
(International Heart Journal Association, 1997) Ramazan Yiǧitoǧlu M.; Fevzi Polat M.; Akçay F.; Ari Z.; Sami Uyanik B.; Özilgili H.M.
Background. Studies have shown that patients with chronic renal failure have a high frequency of cardiocascular atheromatous disease. Methods. We examined serum lipoprotein (a) [Lp(a)], very-low density lipoprotein cholesterol (VLDL-C), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), apolipoprotein A1 (apo A1) and B (apo B), triglyceride (TG) and total cholesterol (TC) levels as possible risk factors for atherosclerosis in 45 patients with chronic renal failure (CRF) treated by hemodialysis (HD) and in 15 CRF patients who were not on HD. A control group of 20 healthy subjects was also studied. Results. The proportion of smokers and body mass indexes were similar between the groups. In both patient groups, higher TG, TC and Lp(a) and lower apo A1 and HDL-C levels in serum were found than in those of controls. Serum apo B and LDL-C were similar in the patients treated by HD and the controls. Serum VLDL-C and LDL-C were similar in the CRF patients who were not on HD and the controls. The highest ratios of apo B/apo A1 and LDL-C/HDL-C were found in HD patients. The highest ratio of TC/HDL-C was found in the other patient group. We found significant correlations between Lp(a) and other parameters of lipoprotein metabolism in CRF patients, both those who were and those who were not on HD. Conclusions. Our results indicate that CRF patients who both were and were not on HD show atherogenic changes in the lipoprotein pattern, and that the increase in Lp(a) during the CRF phase is basically related to the loss of renal function and may also depend on the resultant alterations which are produced in other lipoprotein variables.

Browse

collection.page.browse.recent.head