19672 research outputs found
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Tunable passively Q-switched ytterbium-doped fiber laser with mechanically exfoliated GaSe saturable absorber
No full textA tunable passively Q-switched ytterbium-doped fiber laser using few-layer gallium selenide (GaSe) as a saturable absorber (SA) is demonstrated. The few-layer GaSe SA, which is fabricated by the mechanical exfoliation method, is able to generate a Q-switched fiber laser that has a maximum repetition rate of 92.6 kHz and a minimum pulsed width of 2.3 μs. The highest pulse energy exhibited by the generated pulse is 18.8 nJ with a signal to noise ratio of ∼40 dB. The tunability of the proposed laser covers from 1042 to 1082 nm, giving a tuning range of 40 nm
Characterization of light-control-light system using graphene oxide coated optical waveguide
No full textAn optical waveguide was coated with graphene oxide (GO) using the drop-casting technique to increase the interaction between the waveguide's evanescent field and the GO layer. Subsequently, a 1550 nm tunable laser source and 980 nm pump laser is used to study the potential of the GO-film to control the flow of light through the waveguide by altering the state of the waveguide between transparent (ON) and opaque (OFF). The GO layer has a thickness of 0.40 μm and allows a 1550 nm signal with a peak power of -7.0 dBm and average output power of 0 dBm to pass through at a maximum pump power of 60 mW. The waveguide has a responsivity of ∼0.1 dB mW-1, with the time to switch between the ON and OFF states being about 3 ms
70 nm, broadly tunable passively Q-switched thulium-doped fiber laser with few-layer Mo0.8W0.2S2 saturable absorber
No full textIn this work, a thin Mo0.8W0.2S2 film is proposed and fabricated for the use as a saturable absorber (SA) in a thulium-doped fiber laser (TDFL) cavity. The few-layer Mo0.8W0.2S2 nanoparticles are obtained through hydrothermal exfoliation as a thin film and suspended in a polymer host, which is then placed between two fiber ferrules to serve as an SA. The proposed laser is capable of generating outputs with a maximum repetition rate of 65.79 kHz and a minimum pulse width of 1.84 µs at the maximum pump power of 168.92 mW, as well as pulse energies andpeak powers as high as 35.73 nJ and 13.92 mW. The laser also has a broad tuning output from 1927.2 nm to 1996.8 nm, giving a tuning band of about 70 nm. The generated pulses are stable with a signal-to-noise ratio of 50.0 dB. The proposed laser has a high potential for operation near the 2000 nm wavelength region, with multiple bio-medical and sensing applications
Continued increase of CFC-113a (CCl3CF3) mixing ratios in the global atmosphere: Emissions, occurrence and potential sources
No full textAtmospheric measurements of the ozone-depleting substance CFC-113a (CCl3CF3) are reported from ground-based stations in Australia, Taiwan, Malaysia and the United Kingdom, together with aircraft-based data for the upper troposphere and lower stratosphere. Building on previous work, we find that, since the gas first appeared in the atmosphere in the 1960s, global CFC-113a mixing ratios have been increasing monotonically to the present day. Mixing ratios of CFC-113a have increased by 40 from 0.50 to 0.70 ppt in the Southern Hemisphere between the end of the previously published record in December 2012 and February 2017. We derive updated global emissions of 1.7 Gg yrĝ'1 on average between 2012 and 2016 using a two-dimensional model. We compare the long-term trends and emissions of CFC-113a to those of its structural isomer, CFC-113 (CClF2CCl2F), which still has much higher mixing ratios than CFC-113a, despite its mixing ratios and emissions decreasing since the 1990s. The continued presence of northern hemispheric emissions of CFC-113a is confirmed by our measurements of a persistent interhemispheric gradient in its mixing ratios, with higher mixing ratios in the Northern Hemisphere. The sources of CFC-113a are still unclear, but we present evidence that indicates large emissions in East Asia, most likely due to its use as a chemical involved in the production of hydrofluorocarbons. Our aircraft data confirm the interhemispheric gradient as well as showing mixing ratios consistent with ground-based observations and the relatively long atmospheric lifetime of CFC-113a. CFC-113a is the only known CFC for which abundances are still increasing substantially in the atmosphere
Loss modeling using Burr mixtures
No full textThe first-ever real data application of a two-component Burr mixture distribution is provided. It is fitted to three loss data sets: fire loss claims in Denmark, fire loss claims for three building categories in Belgium and fire loss data in Norway. Each of these data sets exhibits significant bimodality. The fits of the two-component Burr mixture distribution are compared to those of five other two-component mixture distributions: the two-component Weibull mixture, two-component gamma mixture, two-component Pareto mixture, two-component lognormal mixture and the two-component exponential mixture distributions. The Burr mixture distribution is shown to give the best fit for each data set. The relative performances of the fitted distributions were assessed in terms of Akaike information criterion values, Bayesian information criterion values, consistent Akaike information criterion values, corrected Akaike information criterion values, Hannan–Quinn criterion values, density plots and probability–probability plots
CUPRAC assay-guided profiling of antioxidant compounds in methanol extract of Lentinus squarrosulus Mont. mycelium
No full textA cupric reducing antioxidant capacity (CUPRAC)-guided purification approach was performed on a methanol extract of Lentinus squarrosulus (LsqMeOH) by using reversed phase-high performance liquid chromatography. Using reversed phase-high performance liquid chromatography, three fractions were separated arbitrarily named FR1, FR2 and FR3. Results showed that FR2 exhibited the highest antioxidant activity in CUPRAC assay (A450, 0.86) but not significantly different from LsqMeOH (A450, 0.84). FR1 and FR3 showed much lower absorbance, with values (A450, 0.21) and (A450, 0.36) respectively at 1 mg ml-1. The most active fraction (F3) was further subjected to LC-MS/MS to obtain its detailed chemical profile. Uridine, ganoderic acid derivative, and flavonoids were the first time being found in L. squarrosulus antioxidative fractions. The present results indicate that the fraction extracts of L. squarrosulus possess antioxidant properties and can be used as free radical inhibitors. Therefore, this research suggested the potentials of L. squarrosulus as a source of antioxidant extract to be used in food industries (functional food)
Efficacy, safety, and prognostic indicators of first-line sunitinib in patients with metastatic renal cell carcinoma: A single center experience
No full textBackground: We assessed the efficacy and safety of sunitinib as the first-line treatment in metastatic renal cell carcinoma (mRCC) patients. The predictors of survival and efficacy in mRCC as identified from previous studies, including the Memorial Sloan Kettering Cancer Center (MSKCC) and the International Metastatic RCC Database Consortium (IMDC) factors, were also evaluated. Patients and Methods: Data from 56 patients with mRCC, treated with sunitinib at our institute (2006-2014), were analyzed retrospectively. Prognostic factors for overall survival (OS) and progression-free survival (PFS) were evaluated using univariate and multivariate analyses performed by log-rank test and Cox regression. Results: Fifty-one (91.1%) patients received starting dose of sunitinib of 50 mg/day in 4/2 schedule. The median PFS was 12.7 months (95% confidence interval [CI], 4.5-20.9 months) and the median OS was 16.9 months (95% CI, 3.8-29.9 months). The objective response rate was 27.5%. Dose interruption and reduction due to toxicities were required in 37.5% and 60.7% of patients, respectively. The most common Grades 3-4 toxicities were hand-foot syndrome (HFS) (23.2%), thrombocytopenia (16.1%), and hypertension (14.3%). The Eastern Cooperative Oncology Group performance status ≥2, hemoglobin upper limit of normal (ULN), platelet > ULN, no prior nephrectomy, metastatic sites >1, liver metastases, lymph node metastases, and development of HFS were independent prognostic factors. Conclusions: Sunitinib treatment has acceptable efficacy and safety profile in Malaysian mRCC patients. The MSKCC and IMDC factors are relevant for predicting survival in our patient cohort while HFS is a promising prognostic predictor which warrants further investigation
Oral Health Interventions Using Chlorhexidine—Effects on the Prevalence of Oral Opportunistic Pathogens in Stroke Survivors: A Randomized Clinical Trial
No full textObjective: To evaluate the presence of oral opportunistic pathogens among stroke survivors, both before and after oral health care interventions. Methods: A multicenter randomized clinical trial was conducted on hospitalized stroke survivors. Those in the control group were given standard care of oral hygiene (a manual toothbrush and toothpaste), whereas those in the test group were given intense care of oral hygiene (a powered toothbrush and 1% chlorhexidine oral gel). Oral clinical assessments were carried out, and microbiological samples were collected, using concentrated oral rinse samples at 3 time points: baseline, 3 months, and 6 months. Results: The prevalence of oral yeast was significantly reduced in the test group at 6 months (P <.05), but no significant difference was observed over time. A significant reduction was observed in the prevalence of Staphylococcus aureus (P <.01) and aerobic and facultative gram-negative bacilli over time (P <.05), but there were no significant differences noted between groups at 6 months. Candida albicans and Klebsiella pneumoniae were the prominent pathogens determined throughout the trial. Kluyvera strains have also been isolated from this cohort. Conclusion: Oral hygiene intervention using a powered tooth brush and 1% chlorhexidine oral gel was effective in reducing the prevalence of oral opportunistic pathogens
Decomposing the complete r -graph
No full textLet fr(n) be the minimum number of complete r-partite r-graphs needed to partition the edge set of the complete r-uniform hypergraph on n vertices. Graham and Pollak showed that f2(n)=n−1. An easy construction shows that fr(n)≤(1−o(1))(n⌊r/2⌋) and it has been unknown if this upper bound is asymptotically sharp. In this paper we show that fr(n)≤([formula presented]+o(1))(nr/2) for each even r≥4
A Report on Ten Asia Pacific Countries on Current Status and Future Directions of the Genetic Counseling Profession: The Establishment of the Professional Society of Genetic Counselors in Asia
No full textThe Professional Society of Genetic Counselors in Asia (PSGCA) was recently established as a special interest group of the Asia Pacific Society of Human Genetics. Fostering partnerships across the globe, the PSGCA’s vision is to be the lead organization that advances and mainstreams the genetic counseling profession in Asia and ensures individuals have access to genetic counseling services. Its mission is to promote quality genetic counseling services in the region by enhancing practice and curricular standards, research and continuing education. The PSGCA was formally launched during the Genetic Counseling Pre-Conference Workshop held at the 11th Asia-Pacific Conference on Human Genetics in Hanoi, Viet Nam, September 16, 2015. The pre-conference workshop provided an opportunity for medical geneticists and genetic counselors from across 10 Asia Pacific countries to learn about the varied genetic counseling practices and strategies for genetic counseling training. This paper provides an overview of the current status and challenges in these countries, and proposed course of unified actions for the future of the genetic counseling profession