A method for volume stabilization of single, dye-doped water microdroplets with femtoliter resolution

A self-control mechanism that stabilizes the size of Rhodamine B-doped water microdroplets standing on a superhydrophobic surface is demonstrated. The mechanism relies on the interplay between the condensation rate that was kept constant and evaporation rate induced by laser excitation which critically depends on the size of the microdroplets. The radii of individual water microdroplets (>5 um) stayed within a few nanometers during long time periods (up to 455 seconds). By blocking the laser excitation for 500 msec, the stable volume of individual microdroplets was shown to change stepwise.Comment: to appear in the J. Op. Soc. Am.

All-pass section with high gain opportunity

Minaei, Shahram (Dogus Author) -- Conference full title: 33rd International Conference on Telecommunications and Signal Processing, TSP 2010; Baden near Vienna; Austria; 17 August 2010 through 20 August 2010 -- Paper published in Radioengineering, 20 (1) pp. 3-9. Fultext accessible via https://hdl.handle.net/11376/1383In this paper, a new circuit configuration for realizing voltage-mode (VM) all-pass section (APS) is presented. The circuit is cascadable with other VM circuits because of its high input and low output impedances. It consists of two differential difference current conveyors (DDCCs), one grounded resistor and one grounded capacitor. The proposed circuit can be slightly changed by using two additional grounded resistors to provide high gain. Moreover, a quadrature oscillator with minimum number of active and passive elements is derived from the proposed APS. SPICE simulations are performed to verify the theory.Motorol

Effect of bacterial conditioning and the flotation of copper ore and concentrate

In this paper, the effect of bacterial conditioning on KBI Murgul (Turkey) copper concentrate was investigated by the use of Acidothiobacillus ferrooxidans (DSM 11477). The various parameters such as bacterial population, conditioning time and particle size were studied. Test results indicated the copper grade increase of about 22% in flotation copper ore through bacterial conditioning of pyrite surfaces resulting in pyrite depression.Keywords: Chalcopyrite, bio-oxidation, bacteria, mineral surface, froth flotatio

Lasing from single, stationary, dye-doped glycerol/water microdroplets located on a superhydrophobic surface

We report laser emission from single, stationary, Rhodamine B-doped glycerol/water microdroplets located on a superhydrophobic surface. In the experiments, a pulsed, frequency-doubled Nd:YAG laser operating at 532 nm was used as the excitation source. The microdroplets ranged in diameter from a few to 20 um. Lasing was achieved in the red-shifted portion of the dye emission spectrum with threshold fluences as low as 750 J/cm2. Photobleaching was observed when the microdroplets were pumped above threshold. In certain cases, multimode lasing was also observed and attributed to the simultaneous lasing of two modes belonging to different sets of whispering gallery modes.Comment: to appear in Optics Communication

Measurement of the profiles of disorder-induced localized resonances in photonic crystal waveguides by local tuning

Near the band edge of photonic crystal waveguides, localized modes appear due to disorder. We demonstrate a new method to elucidate spatial profile of the localized modes in such systems using precise local tuning. Using deconvolution with the known thermal profile, the spatial profile of a localized mode with quality factor ($Q$) $>10^5$ is successfully reconstructed with a resolution of $2.5 \ \mu$m

Privatization in emerging markets: The case of Turkey

This paper discusses the progress and success of the privatization programs in Turkey between 1985 and 1998. The paper discusses the legal developments, privatization methods, and performance of privatized companies and overall success of privatization by comparing the results of privatization with the aims and objectives stated initially. Within this framework, the paper presents the productivity increases or decreases in various privatized state enterprises, discusses the impact on stock market development, and the privatization revenues and cash results. Only 8.3 percent of the large state-owned enterprises have been privatized during this period. Net cash flow generated from the privatization process does not appear to be satisfactory, and the impact on the stock market and the economy is not very impressive. Turkey still needs to privatize its largest state-owned enterprises in order to realize the full effects of the privatization program

Short- and long-term links among European and US stock markets

Recently, national economies have become more internationalized because of increased trade and increased cooperation between national governments leading to removal of barriers to free flow of goods and services, and financial, physical and human capital. The relationship between equity markets in various countries has been examined extensively in the literature. This study tests the interdependence between stock prices in Germany, the UK, the Netherlands and the US, using daily closing prices for the period between March 1990 and October 1994. Results of the tests show that the US exerts a significant impact on European markets. Moreover, the three European markets influence each other in the short and long run. Therefore, diversification among these national stock markets will not greatly reduce the portfolio risk without sacrificing the expected return

Common coeliacomesenteric trunk: a computed tomography radiological study

Background: There is an increasing trend for administration of invasive radiological interventions, laparoscopic surgery, and transplantation procedures in recent years, and determining the vascular variations prior to these procedures is crucially important. Coeliacomesenteric trunk (CMT) is among these variations. This study aimed to retrospectively evaluate this rare anomaly by computed tomography (CT). Materials and methods: A total of 1000 CT angiography images were analysed retrospectively, and the patients with mesenteric and coeliac arteries arising from the abdominal aorta with a single root were identified. The level that CMT arose, and its branching patterns were determined individually for all patients. Results: Ten patients (6 males and 4 females) with a mean age of 50.2 years (17–87 years) had CMT in CT images. Conclusions: The knowledge of variations in the CMT prior to vascular or laparoscopic interventions will contribute to early intervention in case of a complication, or to avoid from a potential damage

The protective effects of melatonin and vitamin E on antioxidant enzyme activities and epididymal sperm characteristics of homocysteine treated male rats

The aims of this study were to investigate the effects of homocysteine (Hcy) on epididymal sperm characteristics, plasma testosterone level and biochemical changes related to oxidative stress and to examine the effects of melatonin (Mlt) or Vitamin E (VE) administration on these parameters in Hcy-treated male rats. In this study, 32 adult male albino rats of Wistar strain were used. The rats were randomly divided into four groups. The first group of rats received only Hcy (0.71 mg/kg/day) intraperitonially (ip) for 6 weeks. The second group of rats was given Hcy along with simultaneous administration of Mlt (1 mg/kg/day) subcutaneously. The third group of rats received Hcy along with simultaneous administration of VE (125 mg/kg/day, ip). The fourth group of rats served as control during 6 weeks and was daily given 0.1mL of physiological saline (NaCl, 0.9%) ip. While the plasma malondialdehyde level significantly (p < 0.05) increased, the plasma superoxide dismutase, glutathione peroxidase and catalase activities significantly (p < 0.05) decreased in Hcy-treated rats when compared to control rats. Furthermore, the epididymal sperm concentration, the percentage of progressive sperm motility and plasma testosterone level were significantly (p < 0.05) lower in Hcy-treated rats than those of the control rats. The simultaneous administration of Mlt or VE to Hcy-treated animals impeded the decrease in the plasma antioxidant enzyme activities, testosterone level, the epididymal sperm concentration and motility. In conclusion, this study indicates that chronic administration of Hcy has the harmful effect on the epididymal sperm characteristics of male rats. The administration of Mlt or VE can prevent adverse effects of Hcy on the plasma antioxidant enzyme activities, testosterone level, epididymal sperm count and motility in male rats