649 research outputs found

    Ultrashort Q-switched pulses from a passively mode-locked distributed Bragg reflector semiconductor laser

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    A compact semiconductor mode-locked laser (MLL) is presented that demonstrates strong passive Q-switched mode-locking over a wide range of drive conditions. The Q-switched frequency is tunable between 1 and 4 GHz for mode-locked pulses widths around 3.5 ps. The maximum ratio of peak to average power of the pulse-train is >120, greatly exceeding that of similarly sized passively MLLs

    Towards a lattice determination of the B∗BπB^\ast B \pi coupling

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    The coupling gB∗Bπg_{B^\ast B \pi} is related to the form factor at zero momentum of the axial current between B∗B^\ast- and BB-states. This form factor is evaluated on the lattice using static heavy quarks and light quark propagators determined by a stochastic inversion of the fermionic bilinear. The \gBBP coupling is related to the coupling gg between heavy mesons and low-momentum pions in the effective heavy meson chiral lagrangian. The coupling of the effective theory can therefore be computed by numerical simulations. We find the value g=0.42(4)(8)g = 0.42(4)(8). Besides its theoretical interest, the phenomenological implications of such a determination are discussed.Comment: 20 pages, 6 figure

    Soft X-Ray Photoionizing Organic Matter from Comet Wild 2: Evidence for the Production of Organic Matter by Impact Processes

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    The Stardust mission collected both mineral and organic matter from Comet Wild 2 [1,2,3,4]. The organic matter discovered in Comet Wild 2 ranges from aromatic hydrocarbons to simple aliphatic chains and is as diverse and complex as organic matter found in carbonaceous chondrites and interplanetary dust particles.[3,5,6,7,8,9]. Compared to insoluble organic matter from carbonaceous chondrites the organic matter in Comet Wild 2 more closely resembles organic matter found in the IDPS both hydrous and anhydrous. Common processes for the formation of organic matter in space include: Fischer-Tropsch, included with this aqueous large body and moderate heating alterations; UV irradiation of ices; and; plasma formation and collisions. The Fischer-Tropsch could only occur on large bodies processes, and the production of organic matter by UV radiation is limited by the penetration depth of UV photons, on the order of a few microns or less for most organic matter, so once organic matter coats the ices it is formed from, the organic production process would stop. Also, the organic matter formed by UV irradiation would, by the nature of the process, be in-sensitive to photodissocation from UV light. The energy of soft X-rays, 280-300 eV occur within the range of extreme ultraviolet photons. During the preliminary examination period we found a particle that nearly completely photoionized when exposed to photons in the energy range 280-310eV. This particle experienced a long exposure time to the soft x-ray beam which caused almost complete mass loss so little chemical information was obtain. During the analysis of our second allocation we have discovered another particle that photoionized at these energies but the exposure time was limited and more chemical information was obtained

    A comparison of adolescent and adult health state values for the Child Health Utility-9D using profile case best worst scaling

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    The main objective of this study was to compare and contrast adolescent and adult values for the Child Health Utility-9D (CHU9D), a new generic preference based measure of health related quality of life designed for application in the economic evaluation of treatment and preventive programmes for children and adolescents. Previous studies have indicated that there may be systematic differences in adolescent and adult values for identical health states but have failed to use a common valuation technique. An on-line survey including a series of best worst scaling discrete choice experiment questions for health states defined by the CHU9D, was administered to two general population samples comprising adults and adolescents respectively. The results highlight potentially important age related differences in the values attached to CHU9D dimensions. Adults, in general, placed less weight upon impairments in mental health (worried, sad, annoyed) and more weight upon moderate to severe levels of pain relative to adolescents. The source of values (adults or adolescents) has important implications for economic evaluation and may impact significantly upon health care policy. Profile case best worst scaling offers a promising approach for the elicitation and comparison of health state values across population groups.Financial support from a Flinders University seeding grant and an Australian NHMRC Project Grant 1021899 entitled 'Adolescent values for the economic evaluation of adolescent health care treatment and preventive programs' is gratefully acknowledged

    The Influence of Physical Activity on Monocyte Phenotype on Circulating Platelet-Monocyte Complexes in Overweight/Obese Persons

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    Elevated platelet-monocyte complexes (PMC) promote atherosclerosis and are associated with cardiovascular disease. It is unknown whether consistent physical activity (PA) decreases circulating PMCs. Additionally, no one has determined the monocyte phenotype most associated with PMCs. Purposes: 1) to examine the influence of PA on PMCs and their association with inflammatory /prothrombotic markers such as C-reactive protein (CRP), L-selectin (LS), platelet factor 4 (PF4), von Willebrand Factor (vWF), and hemoglobin A1C (HbA1c) and 2) to determine the monocyte phenotype most likely to form PMCs. Methods: Thirty-one overweight/obese subjects (44±5yr, BMI 34.2±5 kg×m2) were divided into two groups: sedentary (SED, n=17) and physically active (PA, n=14) based on physical activity logs. SED participated in \u3c 1 h of formal exercise while PA participated in moderate-high intensity exercise at least 3 h per week. Flow cytometry was used to identify PMCs on the monocyte phenotypes: classical (CD14+CD16-), intermediate (CD14+CD16+), and non-classical (CD14+CD16++). Platelets were identified using the marker CD42a. Results: Percentage of circulating PMCs and median fluorescence intensity of CD42a (MedFI; marker of platelet density per monocyte) were not different between groups; however, monocyte phenotype significantly impacted PMC percentage and MedFI where the lower the CD16 expression, the greater the adhesion of platelets. Classical monocytes (CD16-) had the highest % of PMC, etc. (Fig 1). HbA1c was greater (p=0.031) and LS (p=0.019) was lower in SED compared to PA (Fig. 2). There were no significant associations between any blood marker and PMC percentage, but PF4 was correlated with percent of CD16 -(r= -0.482, p=0.031) and CD16+(r= 0.473, p=0.035) monocytes. Conclusions: The absence of a separation between groups in VO2max may partially explain the lack of a difference in PMCs between groups. Regarding our second aim, classical monocytes appear to be more involved in PMC formation than do CD16+ monocytes with CD16++ having the lowest percentage of cells with platelets adhered (PMC). This observation may be due to the shedding of adhesion molecules from platelets and monocytes during activation from classical (CD16-) to a more inflammatory state (ie. CD16+)

    In silico and in vitro drug screening identifies new therapeutic approaches for Ewing sarcoma.

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    The long-term overall survival of Ewing sarcoma (EWS) patients remains poor; less than 30% of patients with metastatic or recurrent disease survive despite aggressive combinations of chemotherapy, radiation and surgery. To identify new therapeutic options, we employed a multi-pronged approach using in silico predictions of drug activity via an integrated bioinformatics approach in parallel with an in vitro screen of FDA-approved drugs. Twenty-seven drugs and forty-six drugs were identified, respectively, to have anti-proliferative effects for EWS, including several classes of drugs in both screening approaches. Among these drugs, 30 were extensively validated as mono-therapeutic agents and 9 in 14 various combinations in vitro. Two drugs, auranofin, a thioredoxin reductase inhibitor, and ganetespib, an HSP90 inhibitor, were predicted to have anti-cancer activities in silico and were confirmed active across a panel of genetically diverse EWS cells. When given in combination, the survival rate in vivo was superior compared to auranofin or ganetespib alone. Importantly, extensive formulations, dose tolerance, and pharmacokinetics studies demonstrated that auranofin requires alternative delivery routes to achieve therapeutically effective levels of the gold compound. These combined screening approaches provide a rapid means to identify new treatment options for patients with a rare and often-fatal disease

    Lattice Determination of the B∗BπB^\ast B \pi Coupling

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    The coupling gB∗Bπg_{B^\ast B \pi} is related to the form factor at zero momentum of the axial current between B∗B^\ast and BB states. Moreover it is related to the effective coupling between heavy mesons and pions that appear the heavy meson chiral Lagrangian. This coupling has been evaluated on the lattice using static heavy quarks and light quark propagators determined by a stochastic inversion of the fermionic bilinear. We found the value g=0.42(4)(8)g=0.42(4)(8). Beside its theoretical interest, this quantity has phenomenological implications in B→π+lˉlB \to \pi + \bar l l decays.Comment: Lattice 99, 3 page

    Comparison of Body Composition Measurements using a New Caliper, Two Established Calipers, Hydrostatic Weighing, and BodPod

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    Purposes: (1) To compare the Lafayette Instruments (LI) skinfold caliper to the Lange (L) and Harpenden (H) calipers using a diverse subject population. (2) To determine the validity of the LI caliper in a subset of subjects by comparing body compositions from skinfold thicknesses to those measured by hydrostatic weighing (HW) and air displacement plethysmography (ADP). (3) To compare measurements obtained by experienced (EX) and inexperienced (IX) technicians using all three calipers. Methods: Skinfold measurements were performed by both EX and IX technicians using three different calipers on 21 younger (21.2 ± 1.5 yrs) and 20 older (59.2 ± 4 yrs) subjects. Body compositions were calculated using the Jackson-Pollock seven-site and three-site formulas. HW and ADP tests were performed on a subset of subjects (10 younger, 10 older). Results: No significant differences existed between LI and L or H when measurements were made by EX. Further, the LI-EX measurements were highly correlated to both H-EX and L-EX. No significant differences existed in the subgroup between LI-EX and HW or ADP. Skinfold determinations made by EX and IX were similar. Conclusions: Similar body compositions determined using LI, H, and L suggest that LI determines body composition as effectively as H and L. High correlations between the three calipers support this notion. Similar results between LI and HW/ADP subgroup suggest that the LI caliper may be a valid method of measuring body composition. Overall, performance by IX was similar to EX and suggests similar ease of use for all three calipers
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