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

Femtosecond pulse generation from an extended cavity Cr4+: Forsterite laser using graphene on YAG

A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013

Is the mycobacteria-derived purified protein response in atopic asthmatic children different? A case study from Istanbul, Turkey

Background: The response to mycobacteria-derived purified protein (PPD) is mediated primarily by T-helper-1 response and is expected to be inhibited in atopic diseases. The aim of this study was to investigate whether the PPD response is different in atopic asthmatic children. Methods: 40 atopic asthmatic children (mean age 8.3 +/- 4.9 years) and 40 healthy age- and sex-matched children who had received bacillus Calmette-Guerin (BCG) vaccination were included in the study. Five PPD units were administered intradermally to all children and were interpreted after 48 h. Results: There was no correlation between serum total IgE level and PPD induration (p = 0.054). The PPD induration was not statistically different between the children who used inhaled corticosteroid and those who did not. Although the PPD positivity (induration 6 5 mm) rate was higher in atopic asthmatic children (50%) than in healthy children (32.5%), the difference was not found to be statistically significant. The PPD induration in atopic asthmatic children (7.41 8 5.58 mm) was found to be greater than the one in healthy children (5.21 +/- 3.39) (p < 0.039). The induration in atopic asthmatic children (5.21 +/- 3.77) and healthy children (4.43 +/- 2.32) did not show a difference in children who where vaccinated only once with BCG, but it was found to be statistically significantly greater in atopic asthmatic children (12.50 +/- 5.90) than healthy children (7.08 +/- 4.70) who were vaccinated with BCG twice (p < 0.012). The proportion of having a PPD induration of 6 10 mm was found to be higher in atopic asthmatic children than in the healthy ones (32.5 vs. 12.5%) (p < 0.032). Conclusion: Our data showed that the PPD response was stronger in BCG-vaccinated atopic asthmatic children than in healthy BCG-vaccinated ones. Copyright (C) 2004 S. Karger AG, Basel

Femtosecond pulse generation from an extended cavity Cr⁴⁺: Forsterite laser using graphene on YAG

A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013

Graphene mode-locked multipass-cavity femtosecond Cr⁴⁺: Forsterite laser

We report, for the first time to our knowledge, the use of graphene as a saturable absorber in an energy-scaled femtosecond Cr4+ : forsterite laser. By incorporating a multipass cavity, the repetition rate of the original short resonator was reduced to 4.51 MHz, which resulted in the generation of 100 fs, nearly transform-limited pulses at 1252 nm with a peak power of 53 kW. To the best of our knowledge, this is the highest peak power obtained from a room-temperature, femtosecond Cr4+ : forsterite laser mode locked with a graphene saturable absorber. The corresponding pulse energy was 5.3 nJ with only 24 mW of average output power. The saturation fluence and modulation depth of the GSA were measured to be 25 μJ/cm2 and 0.74%, respectively. The nonlinear effects in the Cr4+ : forsterite medium that limit further power scaling were also investigated by using different output couplers. © 2013 Optical Society of America

Graphene mode-locked multipass-cavity femtosecond Cr4+: Forsterite laser

We report, for the first time to our knowledge, the use of graphene as a saturable absorber in an energy-scaled femtosecond Cr4+ : forsterite laser. By incorporating a multipass cavity, the repetition rate of the original short resonator was reduced to 4.51 MHz, which resulted in the generation of 100 fs, nearly transform-limited pulses at 1252 nm with a peak power of 53 kW. To the best of our knowledge, this is the highest peak power obtained from a room-temperature, femtosecond Cr4+ : forsterite laser mode locked with a graphene saturable absorber. The corresponding pulse energy was 5.3 nJ with only 24 mW of average output power. The saturation fluence and modulation depth of the GSA were measured to be 25 μJ/cm2 and 0.74%, respectively. The nonlinear effects in the Cr4+ : forsterite medium that limit further power scaling were also investigated by using different output couplers. © 2013 Optical Society of America

Incidence of H-influenzae in a day-care center

In this study nasopharyngeal haemophilus influenzae flora of healthy children in a day-care center in Istanbul were analyzed, Nasopharyngeal cultures of 168 children between two and five years of age were obtained between December 1, 1992 and April 1, 1993 and investigated. H. influenzae was isolated in 104 cultures. H. influenzae type b (Hib), type f and H. parainfluenzae were found 87 children (51.8%), 15 children (8.9%) and one child (0.6%), respectively, while non-typable H. influenzae was discovered in one child (0.6%). Hib, which is the cause of invasive H. influenzae infection in childhood, was evaluated with respect to age; its incidence was found to be highest in two and three-year-old children, and reduced in children older than four years of age. Although nib was seen in 518 percent of normal children in the day-care center, invasive Hib disease was not seen in any of those children. Therefore, these children have considered carrier of Hib without clinical manifestations