122 research outputs found
Linearly polarized, 3.35 W narrow-linewidth, 1150 nm fiber master oscillator power amplifier for frequency doubling to the yellow
A high-power linearly polarized Yb-doped silica fiber master oscillator power amplifier at 1150 nm is reported. It produced 3.35 W cw and 2.33 W of average power in 1 s pulses at a 100 kHz repetition rate, both with 8 pm linewidth. This is the first report, to the best of our knowledge, of a high-power Yb-doped fiber amplifier at a wavelength longer than 1135 nm. The pulsed output was frequency doubled in a bulk periodically poled near-stoichiometric LiTaO 3 chip to generate 976 mW of average power at 575 nm with an overall system optical-to-optical efficiency of 9.8% with respect to launched pump power
Quasi-three-level Model Applied to Measured Spectra of Nonlinear Absorption and Refraction in Organic Molecules
Materials with a large nonlinear refractive index (2) and relatively small linear and nonlinear absorption losses, namely, two-photon absorption (2PA, of coefficient 2), have long been sought after for applications such as all-optical switching (AOS). Here we experimentally determine the linear and 2PA properties of several organic molecules, which we approximate as centrosymmetric, and use a simplified essential-state model (quasi-three-level model) to predict the dispersion of 2. We then compare these predictions with experimental measurements of 2 and find good agreement. Here “quasi”-three-level means using a single one-photon allowed intermediate state and multiple (here two) two-photon allowed states. This also allows predictions of the figure-of-merit (FOM), defined as the ratio of nonlinear refractive phase shift to the 2PA fractional loss, that determines the viability for such molecules to be used in device applications. The model predicts that the optimized wavelength range for a large FOM lies near the short wavelength linear absorption edge for cyanine-like dyes where the magnitude of 2 is quite large. However, 2PA bands lying close to the linear absorption edge in certain classes of molecules can greatly reduce this FOM. We identify two molecules having a large FOM for AOS. We note that the FOM is often defined as the ratio of real to imaginary parts of the third-order susceptibility ((3)) with multiple processes leading to both components. As explained later in this paper, such definitions require care to only include the 2PA contribution to the imaginary part of (3) in regions of transparency.Abstract © 2016 Optical Society of Americ
Therapist Adherence in the Strong Without Anorexia Nervosa (SWAN) Study: A Randomized Controlled Trial of Three Treatments for Adults with Anorexia Nervosa
The Authors. International Journal of Eating Disorders Published by Wiley Periodicals, Inc.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Objective: To develop a psychotherapy
rating scale to measure therapist adherence
in the Strong Without Anorexia
Nervosa (SWAN) study, a multi-center
randomized controlled trial comparing
three different psychological treatments
for adults with anorexia nervosa. The
three treatments under investigation
were Enhanced Cognitive Behavioural
Therapy (CBT-E), the Maudsley Anorexia
Nervosa Treatment for Adults (MANTRA),
and Specialist Supportive Clinical
Management (SSCM).
Method: The SWAN Psychotherapy Rating
Scale (SWAN-PRS) was developed, after
consultation with the developers of the
treatments, and refined. Using the SWANPRS,
two independent raters initially
rated 48 audiotapes of treatment sessions
to yield inter-rater reliability data. One
rater proceeded to rate a total of 98
audiotapes from 64 trial participants.
Results: The SWAN-PRS demonstrated
sound psychometric properties, and
was considered a reliable measure of
therapist adherence. The three treatments
were highly distinguishable by
independent raters, with therapists
demonstrating significantly more
behaviors consistent with the actual
allocated treatment compared to the
other two treatment modalities. There
were no significant site differences in
therapist adherence observed.
Discussion: The findings provide support
for the internal validity of the SWAN
study. The SWAN-PRS was deemed suitable
for use in other trials involving CBT-E,
MANTRA, or SSCM. VC 2015 The Authors.
International Journal of Eating Disorders
Published by Wiley Periodicals, Inc
Role of carbon cycle observations and knowledge in carbon management
Author Posting. © Annual Reviews, 2003. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Environment and Resources 28 (2003): 521-558, doi:10.1146/annurev.energy.28.011503.163443.Agriculture and industrial development have led to inadvertent changes
in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere and may lead to changes in
climate. The current challenge facing society is to develop options for future management
of the carbon cycle. A variety of approaches has been suggested: direct reduction
of emissions, deliberate manipulation of the natural carbon cycle to enhance sequestration,
and capture and isolation of carbon from fossil fuel use. Policy development to
date has laid out some of the general principles to which carbon management should
adhere. These are summarized as: how much carbon is stored, by what means, and
for how long. To successfully manage carbon for climate purposes requires increased
understanding of carbon cycle dynamics and improvement in the scientific capabilities
available for measurement as well as for policy needs. The specific needs for scientific
information to underpin carbon cycle management decisions are not yet broadly
known. A stronger dialogue between decision makers and scientists must be developed
to foster improved application of scientific knowledge to decisions. This review focuses
on the current knowledge of the carbon cycle, carbon measurement capabilities
(with an emphasis on the continental scale) and the relevance of carbon cycle science
to carbon sequestration goals.The National Center for Atmospheric Research is supported by the National Science
Foundation
Diagnosis and management of venereal campylobacteriosis in beef cattle
BACKGROUND: Bovine venereal campylobacteriosis is caused by Campylobacter fetus subsp. venerealis and its glycerine-tolerant variant Campylobacter fetus subsp. venerealis biovars intermedius. The disease can be economically important when present in cattle herds, causing poor reproductive performance, embryo mortality and abortion. Sensitive and specific diagnostic tests are required in the diagnosis of infection and to inform and monitor disease control. Current tests include bacterial culture and fluorescent antibody testing of preputial sheath washings and an enzyme-linked immunosorbent assay and an agglutination test on vaginal mucus, although the predictive values of these tests can be inadequate in field investigations. Artificial insemination is often considered as a simple control method for bovine venereal campylobacteriosis, but is impractical for many beef suckler herds where breeding takes place at pasture. Commercial vaccines are unavailable in the UK, while the efficacy of autogenous vaccines using a bacterial isolate from infected animals on a specific farm is at best unproven. Hence, for some infected herds, the development of an alternative control strategy based on segregation of potentially infected and uninfected animals in combination with culling or treatment would be desirable. This approach requires meticulous records and herd health management. CASE PRESENTATION: In this paper we highlight difficulties in diagnosing bovine venereal campylobacteriosis and demonstrate the benefits of good record keeping when investigating poor reproductive performance in a beef suckler herd and establishing a herd-specific approach to bio-containment of the infectious cause. CONCLUSIONS: Bovine venereal campylobacteriosis is an economically important disease that should be considered in investigations of suckler herd subfertility problems. Control of the disease based on segregation of potentially infected and uninfected animals in combination with extensive culling can be achieved without the use of artificial insemination or vaccination, but requires meticulous records and strict adherence to herd biosecurity practices
Regulation of the IGFBP-5 and MMP-13 genes by the microRNAs miR-140 and miR-27a in human osteoarthritic chondrocytes
<p>Abstract</p> <p>Background</p> <p>MMP-13 and IGFBP-5 are important factors involved in osteoarthritis (OA). We investigated whether two highly predicted microRNAs (miRNAs), miR-140 and miR-27a, regulate these two genes in human OA chondrocytes.</p> <p>Methods</p> <p>Gene expression was determined by real-time PCR. The effect of each miRNA on IGFBP-5 and MMP-13 expression/production was evaluated by transiently transfecting their precursors (pre-miRNAs) and inhibitors (anti-miRNAs) into human OA chondrocytes. Modulation of IGFBP-5, miR-140 and miR-27a expression was determined upon treatment of OA chondrocytes with cytokines and growth factors.</p> <p>Results</p> <p>IGFBP-5 was expressed in human chondrocytes with its level significantly lower (p < 0.04) in OA. Five computational algorithms identified miR-140 and miR-27a as possible regulators of MMP-13 and IGFBP-5 expression. Data showed that both miRNAs were expressed in chondrocytes. There was a significant reduction (77%, p < 0.01) in miR-140 expression in OA compared to the normal chondrocytes, whereas miR-27a expression was only slightly decreased (23%). Transfection with pre-miR-140 significantly decreased (p = 0.0002) and with anti-miR-140 significantly increased (p = 0.05) IGFBP-5 expression at 24 hours, while pre-miR-27a did not affect either MMP-13 or IGFBP-5. Treatment with anti-miR-27a, but not with anti-miR-140, significantly increased the expression of both MMP-13 (p < 0.05) and IGFBP-5 (p < 0.01) after 72 hours of incubation. MMP-13 and IGFBP-5 protein production followed the same pattern as their expression profile. These data suggest that IGFBP-5 is a direct target of miR-140, whereas miR-27a down-regulates, likely indirectly, both MMP-13 and IGFBP-5.</p> <p>Conclusion</p> <p>This study is the first to show the regulation of these miRNAs in human OA chondrocytes. Their effect on two genes involved in OA pathophysiology adds another level of complexity to gene regulation, which could open up novel avenues in OA therapeutic strategies.</p
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