53 research outputs found
Enhanced transmission of electromagnetic waves through split-ring resonator-shaped apertures
The design of aperture shape is a promising approach for enhanced transmission through a subwavelength aperture. We designed split-ring-resonator (SRR)-shaped apertures in order to increase the transmission through subwavelength apertures by making use of the strong localization of the electromagnetic field in SRR-shaped apertures. We obtained a promising result of 104-fold enhancement by utilizing SRR-shaped apertures. It is possible to use these proposed structures at optical frequencies by making several modifications such as decreasing the sharpness of edges and increasing the gap width. Since SRRs are already being realized at optical frequencies, our proposed SRR-shaped aperture structures are promising candidates for novel applications
Safety assessment of essential and toxic metals in infant formulas
The aim of this study was to assess toxic metal (Cd, Pb and Al) contamination and levels of three essential trace elements (Mn, Cr and Co) in 63 infant formulas. In addition, the levels of these metals in the study samples were compared with the acceptable limits of toxic heavy metals and the recommended daily allowances (RDAs) of essential trace elements. According to our results, the toxic metal levels measured in the formulas were within the acceptable limits, with the exception of Al levels in 8 of the 63 samples. In 16 samples, Mn levels exceeded 600 mu g/day, and the Cr content in 7 samples was higher than 5.5 mu g/day, these amounts being the adequate intake levels for infants. Cobalt levels in 10 formulas were higher than the RDA. In view of these findings, which indicate that metal levels in infant formulas are generally much higher than those found in breast milk, breast milk should be preferred for infant feeding. Moreover, since infants are potentially more susceptible to metals, infant foods should be monitored regularly and checked for contamination by toxic metals as well as for levels of essential trace elements
The Effects of Neopterin on the Viability and Motility of Different HCC Cell Lines
Increased neopterin levels reflect the activation of the cellular immune system which is of importance in the pathogenesis and progression of various diseases such as cancer. However, the effects of neopterin on the biological activity of Hepatocellular carcinoma cells are not yet illuminated. In this study we aim to find the effects of neopterin on viability/cytotxicity and motility of five different HCC cell lines with MTT, SRB and wound healing assays. According to our results, HCC cell lines can be grouped into two categories based on their proliferative and motility response to neopterin, as sensitive and resistant. This data provides us with variable results concerning the proliferation and motility of the cell lines under the effect of neopterin. The underlying molecular mechanisms will be examined in further studies, with a focus on the effect of neopterin on the signalling pathways. Overall, neopterin might have an important role in the hepatocarcinogenesis
Serum Aflatoxin Levels Of The Healthy Adult Population Living In The North And South Regions Of Turkey
Objective: To determine the serum concentrations of aflatoxin B-1 (AFB(1)), aflatoxin B-2 (AFB(2)), aflatoxin G(1) (AFG(1)) and aflatoxin G(2) (AFG(2)) in the healthy adult population living in both the Black Sea and Mediterranean regions of Turkey and to investigate the regional, seasonal and gender variability in aflatoxins (AF) exposure in these regions. Design: Serum AFB(1), AFB(2), AFG(1) and AFG(2) concentrations were analysed by HPLC. Settings: In total, four hundred and eighty-four serum samples were analysed. Subjects: Four hundred and eighty-four healthy adult volunteers living in rural areas of the Black Sea and Mediterranean regions of Turkey were studied. Results: The mean serum concentration of total AF in the Black Sea region was 1.33 ppb (min-max 0.15-3.38 ppb) and 0.90 ppb (min-max 0.18-2.48 ppb) for summer and winter, respectively. In the Mediterranean region, the mean serum concentration of total AF was determined as 0.55 ppb (range 0.04-1.72 ppb) for summer and 0? 45 ppb (range 0.12-1.43 ppb) for winter. The total AF concentrations in serum samples were statistically higher in summer compared with winter for the two regions. The differences between the regions were statistically significant concerning all samples, with higher total AF concentrations in the Black Sea region. Conclusions: The overall results suggest that the Turkish population living in these two regions is continuously exposed to AF, particularly in the summer, and that mycotoxin contamination in food should be monitored routinely for food safety and human health
ANGIOTENSIN 2 TYPE 1/TYPE 2 GENE POLYMORPHISMS IN TURKISH CHILDREN WITH VESICOURETERAL REFLUX AND RECURRENT URINARY TRACT INFECTIONS
50th European-Renal-Association - European-Dialysis-and-Transplant-Association Congress -- MAY 18-21, 2013 -- Istanbul, TURKEYWOS: 000319498201411European Renal Assoc (ERA), European Dialysis & Transplant Assoc (EDTA
Evaluation Of Dihydropteridine Reductase Activities In Patients With Kidney Failure
End-stage renal disease (ESRD) is the inability of the kidneys to remove waste products from the blood. The most important factors causing ESRD that require hemodialysis are diabetes and hypertension. There are limited numbers of studies to evaluate tetrahydrobiopterin pathway in these patients. The aim of the study was to evaluate tetrahydrobiopterin pathway by measuring its important components, biopterin to creatinine concentrations and dihydropteridine reductase activities in diabetes and hypertension patients treated with/without hemodialysis. The patients undergoing hemodialysis were classified as diabetic nephropathy (n=21), hypertensive nephropathy (n=20) and others (n=30), while the controls consisted of healthy subjects (n=21), diabetic subjects (n=23) and hypertensive subjects (n=22) without any renal disorder. It was found that urinary biopterin to creatinine concentrations significantly increased in kidney failure patients undergoing hemodialysis compared to the healthy control group (p<0.05). Additionally, there were significant differences in urinary biopterin to creatinine concentrations between diabetes or hypertension patients and their hypertensive or diabetic control counterparts (both p<0.05). Our results indicated an alteration in tetrahydrobiopterin pathway in ESRD, and in the presence of secondary pathologies such as diabetes and hypertension in the patients undergoing hemodialysis, more considerable changes are observed in the pathway.WoSScopu
Alterations of Central Hypercapnic Respiratory Response Induced by Acute Central Administration of Serotonin Re-Uptake Inhibitor, Fluoxetine
Long-term neurochemical changes are responsible for therapeutic actions of fluoxetine. The role of increased central concentration of serotonin by inhibiting its re-uptake via fluoxetine on the central hypercapnic ventilatory response is complex and little is known. We aimed to research the effect of acute intracerebroventricular (ICV) injection of fluoxetine on hypercapnic ventilatory response in the absence of peripheral chemoreceptor impulses and the role of 5-HT(2) receptors on responses. Eighteen anesthetized albino rabbits were divided as Fluoxetine and Ketanserin groups. For ICV administration of fluoxetine and ketanserin, a cannula was placed in the left lateral ventricle by the stereotaxic method. Respiratory frequency (f(R)), tidal volume (V(T)) and ventilation minute volume (V(E)) were recorded in both groups. ICV fluoxetine (10.12 mmol/kg) injection during normoxia caused significant increases in V(T) and V(E) (both P < 0.01) in the fluoxetine group. When the animals were switched to hypercapnia f(/min), V(T) and V(E) increased significantly. The increases in percentage values in V(T) and V(E) in Fluoxetine + Hypercapnia phase were higher than those during hypercapnia alone (P < 0.01 and P < 0.05, respectively). On blocking of 5-HT(2) receptors by ketanserin (0.25 mmol/kg), the ventilatory response to Fluoxetine was abolished and the degree of increases in V(T) and V(E) in the Ketanserin + Hypercapnia phase were lower than those during hypercapnia alone (P < 0.01 and P < 0.001, respectively). We concluded that acute central fluoxetine increases normoxic ventilation and also augments the stimulatory effect of hypercapnia on respiratory neuronal network by 5-HT(2) receptors in the absence of peripheral chemoreceptor impulses
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