162 research outputs found

    The Investigation of Surplus of Energy and Signal Propagation at Time-Domain Waveguide Modes

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    Classical waveguide theory has been developed bearing on Bernoulli’s product method which results in separation of space and time variables in Maxwell’s equations. The time-harmonic waveguide modes have been stated mathematically for transmitting signals along the waveguides. As a starting point, present studies on transverse-electric (TE) and transverse-magnetic (TM) waveguide modes with previous results are taken and exhibited in an advanced form. They have been obtained within the framework of an evolutionary approach to solve Maxwell’s equations with time derivative. As a result every modal field is obtained in the form of a product of vector functions of transverse coordinates and modal amplitudes. The modal amplitudes which are the functions of axial coordinate z and time t are the central matter of this study. The amplitudes are generated by a potential which is governing by Klein-Gordon equation (KGE). The KGE has remarkable properties of symmetry which has great importance in our analytical studies of the transient modes. Ultimately, in this study, a time-domain waveguide problem is solved analytically in accordance with the causality principle. Moreover, the graphical results are shown for the case when the energy and surplus of the energy for the time-domain waveguide modes are represented via Airy functions

    Serum lipids in Turkish patients with β-thalassemia major and β-thalassemia minor

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    It is well-known that β-thalassemia is associated with changes in plasma lipids and lipoproteins [1,2,3]. To our knowledge, no data are available on lipid profiles in Turkish β-thalassemia major (TM) and β-thalassemia trait (TT) patients together. The aim of this study was to evaluate lipid profiles in two groups of patients with β-TM and β-TT and to compare them with healthy controls. The study included a total of 311 subjects. Group 1 included 131 β-TM patients (mean age: 16.3±7.58 years). Group 2 included 68 β-TT patients (mean age: 7.25±4.43 years). Group 3 consisted of 112 age- and sex-matched healthy controls (mean age: 9±4.7 years). Serum ferritin level was 2487±1103 (range: 661-5745) ng/mL in Group 1. In comparing the correlation between ferritin and lipid parameters, while a significantly negative relationship was detected between ferritin and highdensity lipoprotein cholesterol (HDL-C) (p=0.000, r=-0.602), a significantly positive relationship was detected between ferritin and triglyceride (TG) levels (p=0.02) in TM patients. Serum lipid profiles of the 3 groups are shown in Table 1

    Características y propiedades de los ignimbritos de Bitlis y sus implicaciones ambientales

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    Bitlis rock is used as a construction material and comes from the lava emitted by volcanoes and their subsequent transformation into ignimbrites. This type of rocks has been characterized physically, chemi­cally, toxicologically and radioactively using different procedures including determination of the coefficient of thermal conductivity, gamma spectrometry, ultrasonic speed test, ICP masses and metal extraction. The results indicate that Bitlis rocks have an ACI greater than 1, although their content of radon is lower than other rocks of volcanic origin. Leaching of metals from these rocks indicates that Pb and Cd can provide an infiltration level in the field higher than the level permitted by TCLP and they have undesired toxicological risks. The percent­ages of extraction of other metals also point to this infiltration problem. Despite this, the material offers good qualities for usage as a building material such as its thermal coefficients.La roca Bitlis se utiliza como material de construcción y proviene de la lava emitida por los volcanes y su posterior transformación en ignimbritas. Este tipo de rocas se ha caracterizado física, química, toxicológica y radioactivamente utilizando diferentes procedimientos, incluida la determinación del coeficiente de conductividad térmica, espectrometría gamma, prueba de velocidad ultrasónica, ICP masas y extracción de metales. Los resultados indican que las rocas Bitlis tienen un ACI mayor que 1, aunque su contenido de radón es más bajo que el de otras rocas de origen volcánico. La lixiviación de metales de estas rocas indica que el Pb y el Cd pueden proporcionar un nivel de infiltración en el campo más alto que el nivel permitido por TCLP y tener riesgos toxicológicos no deseados. Los porcentajes de extracción de otros metales también apuntan a este problema de infiltración. A pesar de esto, el material ofrece buenas cualidades para su uso como material de construcción, como pueden ser sus coeficientes térmicos

    Genetic characterization of some Turkish sheep breeds based on the sequencing of the <i>Ovar-DRB1</i> gene in the major histocompatibility complex (MHC) gene region

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    In this research, Ovar-DRB1 gene in the major histocompatibility complex (MHC) gene region was surveyed by DNA sequencing in some of the native sheep breeds that are reared in Turkey. A total of 80 samples were collected from eight different Turkish native sheep breeds, and these samples were used for DNA sequencing.The exon 2 region of Ovar-DRB1 in the MHC gene region was polymerase chain reaction (PCR) amplified and sequenced. A total of 25 new alleles were revealed in the Ovar-DRB1 gene in Turkish native sheep breeds with 24 variable sites; only 13 sites were parsimony informative. The average pairwise genetic distance was 0.029&thinsp;% for the Ovar-DRB1 gene exon 2 region. The sequence variations at eight different positions (7026, 7036, 7040, 7053, 7059, 7069, 7131 and 7214) are found in all of the studied samples. G  →  C transversion at position 7081 is only seen in Akkaraman sheep breed, whereas T  →  C transition at position 7097 is only seen in one sample from the Akkaraman breed. Overall, two main groups were detected among the 25 alleles from Turkish native sheep breeds. All Daǧliç and Kivircik alleles and one allele from Karayaka, Malya and Sakiz are grouped together while all the other breeds are grouped in the other branch.</p

    Effects of Estrogen Replacement Therapy on Lipid Peroxidation and Antioxidant Enzyme Activities of Ovariectomized and Ovariectomized-Diabetic Rats

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    Menopause and diabetes are conditions producing free radicals independently from each other. Estrogen replacement therapy which widely used in postmenopausal period has beneficial effects because of its antioxidant property. The study groups were as follows: ovariectomy (n=8), ovariectomy+17-östradiol (n=8), ovariectomy+diabetes (n=10) and ovariectomy+diabetes+17-östradiol (n=8). Diabetes was induced by streptozotocin (45 mg/kg i.p.) and the treatment with 17-östradiol (0.1 mg/kg/day) was started a week after ovariectomy. After–week long experimental period aortic and uterine tissues were collected from the animals and the malondialdehyde concentration, glutathione peroxidase and catalase activities were quantified. The treatment did not effect blood glucose concentrations, but increased plasma estradiol concentrations. Increased malondialdehyde concentrations were reduced by the treatment in aorta from diabetics and nondiabetics, but the treatment increased malondialdehyde concentrations in nondiabetic uterine while were reducing in diabetic uterine. The treatment also reduced the increased activities of catalase and glutathione peroxidase in aorta from diabetics and nondiabetics, on the other hand the treatment increased the activities of those enzymes in uterine from diabetics and nondiabetics. Our results suggested that estrogen acts as an antioxidant or prooxidant depending on the tissues

    Protective effect of Coriandrum sativum extract against inflammation and apoptosis in liver ischaemia/reperfusion injury

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    Background: The aim of this study was to investigate the anti-inflammatory and antioxidant effects of Coriandrum sativum extract on liver ischaemia reperfusion injury at light microscopic and biochemical levels. Materials and methods: Sham, ischaemia/reperfusion injury (IRI), IRI + Coriandrum sativum extract and only Coriandrum sativum extract groups were formed. Sixty minutes of ischaemia and 60 minutes of reperfusion were performed. In the treatment group, 300 mg/kg/day Coriandrum sativum was given by gavage. Hepatic tissues were fixed in 4% paraformaldehyde. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) enzymes were measured. Nuclear factor-kappa beta (NF-κB), tumour necrosis factor-alpha (TNF-α) and caspase-3 immunohistochemistry staining was performed. Microscopic scoring was performed in terms of sinusoidal congestion, vacuolisation, and necrosis. Results: Sinusoidal enlargement and diffuse congestion, Kupffer cell increase, neutrophil increase in necrotic areas, vacuolisation in hepatocytes, and bile duct proliferation in the portal triad were observed in ischaemia/reperfusion hepatic tissue. Very rare, necrotic areas were observed in the Coriandrum sativum treatment group, while congestion and vacuolisation and bile duct proliferation were decreased compared to the ischaemic group. The AST and ALT levels were increased in the IRI and IRI + Coriandrum sativum groups. When compared to the IRI group, the AST and ALT levels of the Coriandrum sativum were considerably decreased. The IRI and IRI + Coriandrum sativum groups had statistically significant differences in ALP compared to that of the Coriandrum sativum and Sham groups. There was no significant difference between the ALP levels of the IRI and IRI + Coriandrum sativum groups TNF-α, NF-κB and caspase-3 immune positive stained hepatocytes were numerous and widely observed in the injury group. There were positive TNF-α immunohistochemical staining Kupffer cells in the IRI group. In the group treated with Coriandrum sativum, Kupffer cells were not stained, while TNF-α, NF κB and caspase-3 expressing hepatocytes were found to be decreased compared to the IRI group. When the expression values of the TNF-α, NF-κB and caspase-3 groups were evaluated statistically, it was seen that there was a significant decrease in the group treated with Coriandrum sativum. Conclusions: It was found that Coriandrum sativum extract decreased proinflammatory cytokine TNF-α and apoptotic cell death and liver enzymes in liver ischaemia/reperfusion injury

    Failure to mobilize cognitive control for challenging tasks correlates with symptom severity in schizophrenia

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    Deficits in the adaptive, flexible control of behavior contribute to the clinical manifestations of schizophrenia. We used functional MRI and an antisaccade paradigm to examine the neural correlates of cognitive control deficits and their relations to symptom severity. Thirty-three chronic medicated outpatients with schizophrenia and 31 healthy controls performed an antisaccade paradigm. We examined differences in recruitment of the cognitive control network and task performance for Hard (high control) versus Easy (low control) antisaccade trials within and between groups. We focused on the key regions involved in ‘top-down’ control of ocular motor structures – dorsal anterior cingulate cortex, dorsolateral and ventrolateral prefrontal cortex. In patients, we examined whether difficulty implementing cognitive control correlated with symptom severity. Patients made more errors overall, and had shorter saccadic latencies than controls on correct Hard vs. Easy trials. Unlike controls, patients failed to increase activation in the cognitive control network for Hard vs. Easy trials. Reduced activation for Hard vs. Easy trials predicted higher error rates in both groups and increased symptom severity in schizophrenia. These findings suggest that patients with schizophrenia are impaired in mobilizing cognitive control when presented with challenges and that this contributes to deficits suppressing prepotent but contextually inappropriate responses, to behavior that is stimulus-bound and error-prone rather than flexibly guided by context, and to symptom expression. Therapies aimed at increasing cognitive control may improve both cognitive flexibility and reduce the impact of symptoms

    Enhanced topical delivery of dexamethasone by β-cyclodextrin decorated thermoresponsive nanogels

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    Highly hydrophilic, responsive nanogels are attractive as potential systems for the topical delivery of bioactives encapsulated in their three-dimensional polymeric scaffold. Yet, these drug carrier systems suffer from drawbacks for efficient delivery of hydrophobic drugs. Addressing this, β-cyclodextrin (βCD) could be successfully introduced into the drug carrier systems by exploiting its unique affinity toward dexamethasone (DXM) as well as its role as topical penetration enhancer. The properties of βCD could be combined with those of thermoresponsive nanogels (tNGs) based on dendritic polyglycerol (dPG) as a crosslinker and linear thermoresponsive polyglycerol (tPG) inducing responsiveness to temperature changes. Electron paramagnetic resonance (EPR) studies localized the drug within the hydrophobic cavity of βCD by differences in its mobility and environmental polarity. In fact, the fabricated carriers combining a particulate delivery system with a conventional penetration enhancer, resulted in an efficient delivery of DXM to the epidermis and the dermis of human skin ex vivo (enhancement compared to commercial DXM cream: ∼2.5 fold in epidermis, ∼30 fold in dermis). Furthermore, DXM encapsulated in βCD tNGs applied to skin equivalents downregulated the expression of proinflammatory thymic stromal lymphopoietin (TSLP) and outperformed a commercially available DXM cream

    Gas and seismicity within the Istanbul seismic gap

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    Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain
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