Synthesis of Graphene on Gold

Here we report chemical vapor deposition of graphene on gold surface at ambient pressure. We studied effects of the growth temperature, pressure and cooling process on the grown graphene layers. The Raman spectroscopy of the samples reveals the essential properties of the graphene grown on gold surface. In order to characterize the electrical properties of the grown graphene layers, we have transferred them on insulating substrates and fabricated field effect transistors. Owing to distinctive properties of gold, the ability to grow graphene layers on gold surface could open new applications of graphene in electrochemistry and spectroscopy.Comment: 8 pages, 4 figure

Fundamental structure of Fresnel diffraction: natural sampling grid and the fractional Fourier transform

Cataloged from PDF version of article.Fresnel integrals corresponding to different distances can be interpreted as scaled fractional Fourier transformations observed on spherical reference surfaces. We show that by judiciously choosing sample points on these curved reference surfaces, it is possible to represent the diffracted signals in a nonredundant manner. The change in sample spacing with distance reflects the structure of Fresnel diffraction. This sampling grid also provides a simple and robust basis for accurate and efficient computation, which naturally handles the challenges of sampling chirplike kernels. © 2011 Optical Society of America

Explaining spatial variation in housing construction activity in Turkey

In Turkey, there has been a strong policy narrative that has emphasized the importance of construction activity as a driver of economic growth. This has given shape to a central state-led policy regime that has sought to ensure that planners and other urban policy makers develop plans and strategies that support construction activity. Against this backdrop, and a recent history of uneven spatial development, this paper seeks to understand what this policy imperative might mean for housing construction activity in different provinces. It seeks to reflect on both the relationship between the state and the market, and the interaction between state policies, economic drivers and levels of construction activity. The evidence presented in the paper suggests that uneven spatial development might be explained in different ways in different provinces. Although, in many cases, patterns of construction activity are consistent with economic fundamentals, there are important exceptions in some regions where arguably activity levels are at odds with prior expectations

A Cholesterol-Based Allostery Model of T Cell Receptor Phosphorylation

Signaling through the T cell receptor (TCR) controls adaptive immune responses. Antigen binding to TCRαβ transmits signals through the plasma membrane to induce phosphorylation of the CD3 cytoplasmic tails by incompletely understood mechanisms. Here we show that cholesterol bound to the TCRβ transmembrane region keeps the TCR in a resting, inactive conformation that cannot be phosphorylated by active kinases. Only TCRs that spontaneously detached from cholesterol could switch to the active conformation (termed primed TCRs) and then be phosphorylated. Indeed, by modulating cholesterol binding genetically or enzymatically, we could switch the TCR between the resting and primed states. The active conformation was stabilized by binding to peptide-MHC, which thus controlled TCR signaling. These data are explained by a model of reciprocal allosteric regulation of TCR phosphorylation by cholesterol and ligand binding. Our results provide both a molecular mechanism and a conceptual framework for how lipid-receptor interactions regulate signal transduction. The TCR can adopt an inactive, resting or an active, primed state. Schamel and colleagues show that the TCR is in equilibrium between these states. Peptide-MHC binding stabilizes the primed state that can be phosphorylated. Cholesterol binding stabilizes the resting state and thereby tunes the TCR activation threshold.</p

Parasitic Appendicitis From Past to Present in Turkey

Background: Understanding the etiology of appendicitis is important for developing effective treatments the rela­tionship between parasitic appendicitis and various socio-cultural factors were examined, particu­larly with respect to the incidence of literacy. The aim of the article was to research the relations between para­sitic appendicitis and literacy ratio in population.Methods: Cases of parasitic appendicitis resulting in surgery performed at Buca Seyfi Demirsoy Large State Hospital Surgery Clinic between 2002 and 2009 were retrospectively reviewed and classified accord­ing to age, sex, type of parasite, morbidity, and mortality. Studies conducted in different regions of Turkey as well as in other countries were reviewed to determine if there was a relationship between para­sitic appendicitis and literacy. Results: Of the 1,969 appendectomy cases reviewed, nine were classified as parasitic appendicitis (0.45%). Enterobius vermicularis was observed in seven cases and Taenia spp. in two. The average age was 26.4 yr. No morbidity or mortality was found.Conclusion: The data were compared with a retrospective review of studies conducted in the same regions and a decrease in the rate of parasitic appendicitis was observed during the period between the two re­views. It was determined that a low literacy rate was associated with an increase in the incidence of para­sitic appendicitis. Observations made between different countries also produced similar results. In coun­tries where the incidence of parasitic appendiciticis was greater than 1.5%, the literacy rate was less than 88%. To avoid appendectomy resulting from parasites, it is important to increase education and literacy. In some areas, individuals with appendicitis undergo surgery due to a lack of education or poor literacy

Extracorporeal life support in pediatric cardiac dysfunction

<p>Abstract</p> <p>Background</p> <p>Low cardiac output (LCO) after corrective surgery remains a serious complication in pediatric congenital heart diseases (CHD). In the case of refractory LCO, extra corporeal life support (ECLS) extra corporeal membrane oxygenation (ECMO) or ventricle assist devices (VAD) is the final therapeutic option. In the present study we have reviewed the outcomes of pediatric patients after corrective surgery necessitating ECLS and compared outcomes with pediatric patients necessitating ECLS because of dilatated cardiomyopathy (DCM).</p> <p>Methods</p> <p>A retrospective single-centre cohort study was evaluated in pediatric patients, between 1991 and 2008, that required ECLS. A total of 48 patients received ECLS, of which 23 were male and 25 female. The indications for ECLS included CHD in 32 patients and DCM in 16 patients.</p> <p>Results</p> <p>The mean age was 1.2 ± 3.9 years for CHD patients and 10.4 ± 5.8 years for DCM patients. Twenty-six patients received ECMO and 22 patients received VAD. A total of 15 patients out of 48 survived, 8 were discharged after myocardial recovery and 7 were discharged after successful heart transplantation. The overall mortality in patients with extracorporeal life support was 68%.</p> <p>Conclusion</p> <p>Although the use of ECLS shows a significantly high mortality rate it remains the ultimate chance for children. For better results, ECLS should be initiated in the operating room or shortly thereafter. Bridge to heart transplantation should be considered if there is no improvement in cardiac function to avoid irreversible multiorgan failure (MFO).</p

Distribution of mast cells in lung tissues of rats exposed to biomass smoke

This study was designed to evaluate the distribution of mast cells in the lung tissues of rats exposed to biomass  smoke. Fifty six female Wistar albino adult rats were used. They were divided into two experimental groups  (control and biomass smoke-treated), each containing 28 animals. Control rats were not exposed to the  biomass smoke at any time during the experiment. Rats in the treatment group were exposed daily (one hour)  to biomass smoke for 3, 6 or 9 months. Lung tissues samples were obtained under deep anesthesia from the  randomly selected 7 animals in both groups. Lung tissues were fixed in Mota’s fixative (BLA) for 24 h and  embedded in paraffin. Sections of 6 μm thickness were cut and stained with 0.5% toluidine blue in 0.5 N  hydrochloric acid at pH 0.5 for 30 min. The numbers of mast cell in lung tissues of the animals exposed to  the biomass for 6 or 9 months were significantly (P&lt;0.05) higher than controls. This study showed that long  term exposure to biomass smoke was associated with the increased number of mast cells in the lung.