317 research outputs found
Immobilization of catalase via adsorption into natural and modified active carbon obtained from walnut in various methods
In the present work, the immobilization of catalase into natural active carbon and active carbon modified by hydrochloric acid was carried out. In the experimental section, the effects of pH, ionic strength andreaction temperature were chosen as parameters, with experiments performed in batch system. For the optimization of immobilization procedure, values of kinetic parameters were evaluated. It was observedthat storage and operational stabilities of the enzyme increased with immobilization. The results obtained from experiments showed that active carbon is a valuable support for the adsorption of enzymes
Deep levels in a-plane, high Mg-content MgxZn1-xO epitaxial layers grown by molecular beam epitaxy
Deep level defects in n-type unintentionally doped a-plane MgxZn1−xO, grown by molecular beam epitaxy on r-plane sapphire were fully characterized using deep level optical spectroscopy (DLOS) and related methods. Four compositions of MgxZn1−xO were examined with x = 0.31, 0.44, 0.52, and 0.56 together with a control ZnO sample. DLOS measurements revealed the presence of five deep levels in each Mg-containing sample, having energy levels of Ec − 1.4 eV, 2.1 eV, 2.6 V, and Ev + 0.3 eV and 0.6 eV. For all Mg compositions, the activation energies of the first three states were constant with respect to the conduction band edge, whereas the latter two revealed constant activation energies with respect to the valence band edge. In contrast to the ternary materials, only three levels, at Ec − 2.1 eV, Ev + 0.3 eV, and 0.6 eV, were observed for the ZnO control sample in this systematically grown series of samples. Substantially higher concentrations of the deep levels at Ev + 0.3 eV and Ec − 2.1 eV were observed in ZnO compared to the Mg alloyed samples. Moreover, there is a general invariance of trap concentration of the Ev + 0.3 eV and 0.6 eV levels on Mg content, while at least and order of magnitude dependency of the Ec − 1.4 eV and Ec − 2.6 eV levels in Mg alloyed samples
Diurnal gradual heat stress affects antioxidant enzymes, proline accumulation and some physiological components in cotton (Gossypium hirsutum L.)
Even though high temperatures significantly reduce both vegetative growth and yield in cotton, very little is known about the effects of heat stress on cotton antioxidant system. Thus, the effects of gradual heat stress on cotton growth in controlled conditions were investigated in the present study. At squaring stage, cotton plants were subjected to two different temperatures, 38 and 45°C to determine the influence of heat stress on the plants. The results of the present study showed that heat stress did not significantly altered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the leaves, whereas there was a remarkable decline in proline quantity of the leaves of plants subjected to 45°C heat stress. As for the amount of total chlorophyll content, a slight increase at plants treated with 38°C temperature was observed. Furthermore, the activities of some enzymes such as superoxide dismutase (SOD), which were associated with heat stress response in other plants was also investigated. For example, there was decline in the activitity of SOD in the plants exposed to high temperatures. On the contrary, catalase (CAT) activity increased at 45°C; peroxidase (POX) activity increased at 38°C and ascorbate peroxidase (APX) activity increased at 38 and 45°C. The results from this study suggest a potential role for CAT, POX and APX in the reduction of elevated levels of H2O2 in cotton plants grown under heat stress condition. To sum up, it could be concluded that, diurnal gradual heat stress caused a low oxidative injury in cotton
Multidetector computed tomography findings of an asymptomatic levoatrial cardinal vein with an interatrial course
A 57-year-old female patient with a family history of coronary artery diseaseadmitted to our hospital for the coronary check-up. A coronary angiographywas performed with ECG-gated 128 slice dual source computed tomography.Multidetector computed tomography (MDCT) showed, in addition to the normalcoronary arteries, a persistent levoatrial cardinal vein (LCV) draining into vena cavasuperior. ECG-gated cardiac MDCT is a useful tool showing the origin, course, anddrainage site of LCV
Impurity-free quantum well intermixing for large optical cavity high-power laser diode structures
We report on the correlation of atomic concentration profiles of diffusing species with the blueshift of the quantum well luminescence from both as-grown and impurity free quantum wells intermixed on actual large optical cavity high power laser diode structures. Because it is critical to suppress catastrophic optical mirror damage, sputtered SiO2 and thermally evaporated SrF2 were used both to enhance and suppress quantum well intermixing, respectively, in these (Al)GaAs large optical cavity structures. A luminescence blueshift of 55 nm (130 meV) was obtained for samples with 400 nm thick sputtered SiO2These layers were used to generate point defects by annealing the samples at 950 °C for 3 min. The ensuing Ga diffusion observed as a shifting front towards the surface at the interface of the GaAs cap and AlGaAs cladding, as well as Al diffusion into the GaAs cap layer, correlates well with the observed luminescence blue shift, as determined by x-ray photoelectron spectroscopy. Although this technique is well-known, the correlation between the photoluminescence peak blue shift and diffusion of Ga and Al during impurity free quantum well intermixing on actual large optical cavity laser diode structures was demonstrated with both x ray photoelectron and photoluminescence spectroscopy, for the first time. © 2016 IOP Publishing Ltd
Cranial magnetic resonance imaging as a screening tool for evaluation of silent brain ischemia in severe coronary artery disease: A clinical based study
Aim: Silent brain ischemia (SBI), defined as ischemic changes and infarcts without neurologic signs, is an established marker of poor survival. Magnetic resonance imaging (MRI) is useful to define SBI and white matter hyperintensities that correspond to microangipathic ischemic disease. This study aimed to investigate the relationship among SBI, white matter lesions and the extent of coronary artery disease (CAD), and to determine possible predictors of SBI. Material and Methods: A total 10640 patients who underwent coronary angiography were retrospectively screened to reveal 312 patients who had been evaluated with a subsequent cranial MRI within 6 months. CAD severity was established with Gensini score and MRIs were evaluated to determine presence of SBI and white matter hyperintensities scored by Fazekas. Finally, 58 patients with SBI and 254 without SBI consisted SBI and non-SBI groups. Results: Patients with SBI were significantly older with higher prevalence of male gender than the non-SBI patients. Both Gensini and Fazekas scores were higher in SBI-group (p<0.001). Fazekas score was positively correlated with Gensini score (r=0.219, p<0.001) and age (r=0.465, p<0.001). In the logistic regression analysis; age, male gender and Gensini score were identified as the independent predictors of SBI. Conclusion: Although SBIs don’t present neurological symptoms they are associated with poor survival and future stroke. Our data suggest that cranial MRI may be a screening tool in risk stratification, particularly in elderly male patients with multivessel CAD. Our study also depicted that age, male gender and high Gensini scores are the independent predictors of SBI. © 2020, Duzce University Medical School. All rights reserved
Effect of pregnancy and foetal number on diameter of corpus luteum, maternal progesterone concentration and oxidant/antioxidant balance in ewes
The aim of this study was to determine the changes in diameter
of corpus luteum (CL), maternal progesterone (P) concentration,
lipid peroxidation and non-enzymatic antioxidant levels
along with enzymatic antioxidant activities in pregnant ewes
bearing single and twin foetuses. The ewes were selected from
healthy animals that were brought to the abattoir for
slaughtering. The ewes were divided into three groups: Group
1 (non-pregnant, non-oestrous, n = 30), Group 2 (pregnant
bearing a single foetus, n = 30) and Group 3 (pregnant
bearing twin foetuses, n = 12) after they were slaughtered.
Pregnant ewes were in the first half of the pregnancy. The
diameter of CL and P concentration of pregnant ewes bearing
a single foetus or twin foetuses were found higher than that
found in non-pregnant ewes. Similarly, the P concentration of
pregnant ewes bearing twin foetuses was higher than that
found in pregnant ewes bearing a single foetus. Malondialdehyde
(MDA) level in pregnant ewes bearing twin foetuses was
higher than that found in both non-pregnant and pregnant
ewes bearing a single foetus. The serum glutathione (GSH)
level and glutathione-peroxidase (GSH-Px) activity of pregnant
ewes bearing twin foetuses were found lower than that
found in non-pregnant ewes. Additionally, the GSH-Px
activity of pregnant ewes bearing twin foetuses was found
lower than that found in pregnant ewes bearing a single foetus.
No significant difference was found between pregnant ewes
bearing female and male foetus with respect to diameter of CL,
P concentration and oxidative stress parameters. There were
significant positive correlations between foetal number (0, 1, 2)
and diameter of CL, P concentration, MDA level, and between
P concentration and diameter of CL, MDA level. However,
significant negative correlations were found between foetal
number (0, 1, 2) and GSH level, GSH-Px activity, and between
P concentration and GSH-Px activity. In conclusion, the
diameter of CL enlarges, P production increases and
oxidant ⁄ antioxidant balance impairs because of the gestation
stress in ewes during pregnancy
Systematic review with meta-analysis: cytokines in fibromyalgia syndrome
<p>Abstract</p> <p>Background</p> <p>To perform a systematic review and meta-analysis on cytokine levels in patients with fibromyalgia syndrome (FMS).</p> <p>Methods</p> <p>Through December 2010 we systematically reviewed the databases PubMed, MEDLINE, and PsycINFO and screened the reference lists of 22 review articles for suitable original articles. Original articles investigating cytokines in patients with FMS were included. Data were extracted by two independent authors. Differences of the cytokine levels of FMS patients and controls were summarized by standardized mean differences (SMD) using a random effects model. Study quality was assessed applying methodological scores: modified Center of Evidence Based Medicine, Newcastle-Ottawa-Scale, and Würzburg Methodological Quality Score.</p> <p>Results</p> <p>Twenty-five articles were included investigating 1255 FMS patients and 800 healthy controls. Data of 13/25 studies entered meta-analysis. The overall methodological quality of studies was low. The results of the majority of studies were not comparable because methods, investigated material, and investigated target cytokines differed. Systematic review of the selected 25 articles revealed that FMS patients had higher serum levels of interleukin (IL)-1 receptor antagonist, IL-6, and IL-8, and higher plasma levels of IL-8. Meta-analysis of eligible studies showed that FMS patients had higher plasma IL-6 levels compared to controls (SMD = -0.34 [-0.64, -0.03] 95% CI; p = 0.03). The majority of investigated cytokines were not different between patients and controls.</p> <p>Conclusions</p> <p>The pathophysiological role of cytokines in FMS is still unclear. Studies of higher quality and with higher numbers of subjects are needed.</p
Effects of pomegranate juice consumption on sperm quality, spermatogenic cell density, antioxidant activity and testosterone level in male rats
Background & aim: Pomegranate fruit is inescapably linked with fertility, birth and eternal life
because of its many seeds. The aim of this study was to investigate the effects of pomegranate
juice (PJ) consumption on sperm quality, spermatogenic cell density, antioxidant activity and
testosterone level of male healthy rats.
Methods: Twenty-eight healthy adult male Wistar rats were divided into four groups; each
group containing seven rats. One milliliter distilled water, 0.25 mL PJ plus 0.75 mL distilled
water, 0.50 mL PJ plus 0.50 mL distilled water and 1 mL PJ were given daily for seven weeks
by gavage to rats in the first, second, third and fourth groups, respectively. Body and reproductive
organ weights, spermatogenic cell density, sperm characteristics, levels of antioxidant
vitamins, testosterone, and lipid peroxidation and, antioxidant enzyme activities were investigated.
All analyses were done only once at the end of the seven week study period. Data
were compared by analysis of variance (ANOVA) and the degree of significance was set at
P < 0.05.
Results: A significant decrease in malondialdehyde (MDA) level and marked increases in glutathione
(GSH), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, and vitamin C
level were observed in rats treated with different doses of PJ. PJ consumption provided an
increase in epididymal sperm concentration, sperm motility, spermatogenic cell density and
diameter of seminiferous tubules and germinal cell layer thickness, and it decreased abnormal
sperm rate when compared to the control group. Conclusion: The results suggest that PJ consumption improves sperm quality and antioxidant
activity of rats
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