Step-tunable all-optical wavelength conversion usingcavity-enhanced four-wave mixing

Step tuning of a wavelength converter using cavity-enhanced four-wave mixing in a multimode semiconductor laser is experimentally and theoretically demonstrated. The converter is modulation-format transparent and is shown experimentally to have a high conversion efficiency (>-10 dB) and to be step-tunable over a large conversion range (>2.5 THz). A mathematical model of the wavelength converter is derived and is used to simulate step tuning of this device and to examine the relationship between conversion efficiency and information bandwidth of the converter     

Quinine for nocturnal leg cramps: a meta-analysis including unpublished data

OBJECTIVE: With respect to the use of quinine for the treatment of nocturnal leg cramps, to determine whether the findings of a previously performed meta-analysis of published data are altered with the addition of unpublished data, and whether publication bias is present in this area. DESIGN: A meta-analysis of eight (four published and four unpublished) randomized, double-blind, placebo-controlled trials, seven of which had a crossover design. SETTING: Randomized trials that were available as of July 1997. SUBJECTS: Ambulatory patients (659) who suffered from regular nocturnal leg cramps. MAIN RESULTS: When individual patient data from all crossover studies were pooled, persons had 3.60 (95% confidence interval [CI] 2.15, 5.05) fewer cramps in a 4-week period when taking quinine compared with placebo. This compared with an estimate of 8.83 fewer cramps (95% CI 4.16, 13.49) from pooling published studies alone. The corresponding relative risk reductions were 21% (95% CI 12%, 30%) and 43% (95% CI 21%, 65%), respectively. Compared with placebo, the use of quinine was associated with an increased incidence of side effects, particularly tinnitus. Publication bias is present in the reporting of the efficacy of quinine for this indication, as almost all published studies reported larger estimates of its efficacy than did unpublished studies. CONCLUSIONS: This study confirms that quinine is efficacious in the prevention of nocturnal leg cramps. However, its benefit may not be as large as reported from the pooling of published studies alone. Given the side effect profile of quinine, nonpharmacologic therapy (e.g., regular passive stretching of the affected muscle) is the best first-line treatment. For persons who find this ineffective and whose quality of life is significantly affected, a trial of quinine is warranted. Prescribing physicians must closely monitor the risks and benefits in individual patients. Publication bias is present in this area even though there is controversy about the role of quinine in the treatment of leg cramps. To minimize the possibility of this bias, persons performing medication-related meta-analyses should seek high-quality unpublished data from drug regulatory agencies and pharmaceutical companies.     

Gamma-interferon activates a nuclear protein that binds to the gamma-interferon activation site of the thyroglobulin gene

In 1989, a population-based cohort of persons aged > or = 50 years was established in an urban area of Guinea-Bissau, West Africa. Overall, 346 persons were interviewed in detail about risk behaviors and had capillary blood drawn. Among women, 12.4% were HTLV-1 seropositive, compared with 4.6% in men. No HTLV-2 was found. Seropositivity varied considerably according to place of birth and ethnic group. In women, but not in men, HTLV-1 seropositivity was strongly associated with early sexual debut (10-14 yrs, 33.3%; 15-17 yrs, 26.0%; 18-20 yrs, 6.5%; 21+ yrs, 0%; ptrend = 0.001), lifetime number of male partners (ptrend = 0.006), and the male partner's number of co-wives (ptrend = 0.006). There was also a 3.1-fold increased risk of being HTLV-1 seropositive if the woman was also HIV-2 seropositive. In a multivariate-risk-factor analysis, the strongest association with HTLV-1 was a history of having been bitten by a monkey (n = 11; combined OR adjusted = 10.1; 95% CI 2.3-44.4). Ornamental scarification was associated with a 3.3-fold increased risk. Ethnic affiliation also significantly influenced the risk of being HTLV-1 seropositive. Follow-up performed in January 1996 revealed no difference in survival between HTLV-1-seropositive and -seronegative individuals over 6 years (rate ratio = 1.4, 95% CI 0.7-2.8). In conclusion, this population, which has very high HIV-2 seroprevalence, is also highly endemic for HTLV-1. Whereas sexual behaviors are clearly important for HTLV-1 spread in women, non-sexual risk factors were the only ones of potential importance in men. HTLV-1 had no impact on survival in this older population.     

Age differences in hostility among middle-aged and older adults.

Multiple measures of hostility were administered to middle-aged and older volunteers. There was a positive association between age and self-report measures reflecting hostile beliefs about others, including cynicism and suspiciousness. There was a weak inverse relationship between age and self-report measures of the overt expression of anger and aggression, but no association between age and measures of covert hostility was found. There was a positive relationship between age and an assessment of hostile behavior that was based on the respondent's interaction style during an interview. The magnitude of these age trends did not differ between men (n?=?50) and women (n?=?75). Findings illustrate the multidimensional nature of hostility. They also have practical implications for older people because hostility is associated with psychological well-being and has been shown to have consequences for health and longevity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of a selective transport medium for gastric biopsy specimens to be cultured for Helicobacter pylori

Since the means of culturing Helicobacter pylori may not be available in some laboratories, prolonging the survival of this organism during transportation is a major concern in terms of improving detection rates. A selective transport medium was evaluated for the preservation of H. pylori from 254 gastric biopsy specimens collected from a rural area in China where culturing is not feasible. Gastric biopsy specimens were inoculated in sterile broth consisting of brain heart infusion (BHI) broth, horse serum, and yeast extract supplemented with vancomycin, amphotericin B, and nalidixic acid (VAN). Of the 254 biopsy specimens, 238 were identified by histology to have H. pylori infection. Total rates of recovery of H. pylori from the H. pylori-positive gastric biopsy specimens stored in the BHI-VAN broth ranged from 76 to 46% after storage of specimens for 5 to 9 days. In conclusion, the selective medium is useful for prolonging the survival of H. pylori in gastric biopsy specimens for which immediate culture is not feasible.     

Quality ratings of a hospital foodservice department by inpatients and postdischarge patients

OBJECTIVES: To examine quality of food and nutrition services using the ratings of inpatients and patients who had been discharged (postdischarge patients). DESIGN: Questionnaires were used to collect perceptions of inpatients and postdischarge patients on the quality of food and nutrition services. A 5-point scale allowed subjects to rate quality from very poor to very good. SUBJECTS: Questionnaires were completed by 252 inpatients and 437 postdischarge patients of a midwestern teaching hospital. STATISTICAL ANALYSIS: Analysis of variance was used to assess differences in quality ratings on the basis of demographic variables. Stepwise regression was used to determine variables that best predicted overall satisfaction. Paired t tests were conducted to compare matched inpatient and postdischarge ratings. RESULTS: Ratings of food and nutrition services indicated that patients were satisfied; few differences were found in ratings on the basis of patient demographics. Food quality was the best predictor of overall satisfaction for both inpatients and postdischarge patients. As patient expectations were increasingly met or exceeded, patient ratings of quality increased. The majority of patients in the matched sample gave the same ratings on the inpatient and postdischarge questionnaires. APPLICATIONS: Foodservice managers who desire to improve patient satisfaction should focus attention on meeting or exceeding patient expectations for food quality.     

Study of plasma-etched and laser-irradiated polyamide materials

Surface morphological structures of the Low Temperature Plasma (LTP) and UV Excimer Laser treated polyamide materials were investigated. The effects of different parameters were studied by using Scanning Electron Microscope (SEM). For LTP treatment, different non-polymerizing gases (oxygen, argon), discharge power and exposure time were selected as treatment parameters. For Laser treatment, high-fluence (above ablation threshold), low-fluence (below ablation threshold) and number of pulses were studied. High-fluence laser treatment gives the most distinct ripple-like structures on the surface of polyamide and these structures are more obvious when the number of pulses increases. Low-fluence treated polyamide develops some stripes of sub-micron size within a narrow fluence window. On the other hand, oxygen and argon plasma also gives ripple-like structures but with smaller dimensions than those due to high-fluence laser treatment. Although the morphological modification features on the polyamide fiber surface developed under laser and LTP treatments are not identical, they have certain similarity. Electronic Publication     

Failure mechanisms in thick composites under compressive loading

Failure mechanisms were studied in a unidirectional carbon/epoxy composite under uniform and linearly varying longitudinal compression. The first failure mechanism is shear yielding or shear failure in the matrix precipitated by initial fiber misalignment. It was shown how an initial fiber misalignment of 1.5° can produce the measured compressive strength of 1725 MPa (250 ksi). Matrix failure is followed by fiber buckling and fracture, resulting in the formation of a kink band. The kink band orientation is constant in the range of β = 20–30°, whereas the kink angle a varies from a small initial value to a maximum value of 2β. Kink band widths varied between 4 and 20 fiber diameters. Kink bands can occur on different planes which can rotate along the band. Kink band multiplication or broadening with increasing stress was observed at points where the maximum kink angle was reached.     

Intrinsic equivalent circuit of quantum-well lasers

An intrinsic equivalent circuit of quantum-well lasers that takes the capture of carriers into the quantum well into account is presented. Several qualitative features in the modulation response and the device impedance are revealed. The dependences on the carrier capture and escape rates are discussed     

Voltammetric measurement of oxygen in single neurons using platinized carbon ring electrodes.

Naflon-coated ultrasmall platinum ring electrodes have been implanted in the giant dopamine neuron of the pond snail Planorbis corneus, and the oxygen concentration inside these single neurons has been estimated. Experimental data suggest that the intracellular oxygen level in the identified dopamine neuron of P. corneus is approximately 0.032 mM. The oxygen concentration immediately outside the cell (ca. 10 microns away from the cell) is 0.041 mM. Furthermore, staircase voltammetry can be used to monitor dynamic changes in oxygen concentration inside the cell after bathing with Ringer's solution saturated with air/oxygen. Data obtained for intracellular oxygen concentrations suggest that intracellular oxygen consumption is increased following potassium chloride-induced stimulation of these cells.