5,867 research outputs found

    \u3cem\u3eIn vivo\u3c/em\u3e Imaging of Human Cone Photoreceptor Inner Segments

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    Purpose. An often overlooked prerequisite to cone photoreceptor gene therapy development is residual photoreceptor structure that can be rescued. While advances in adaptive optics (AO) retinal imaging have recently enabled direct visualization of individual cone and rod photoreceptors in the living human retina, these techniques largely detect strongly directionally-backscattered (waveguided) light from normal intact photoreceptors. This represents a major limitation in using existing AO imaging to quantify structure of remnant cones in degenerating retina. Methods. Photoreceptor inner segment structure was assessed with a novel AO scanning light ophthalmoscopy (AOSLO) differential phase technique, that we termed nonconfocal split-detector, in two healthy subjects and four subjects with achromatopsia. Ex vivo preparations of five healthy donor eyes were analyzed for comparison of inner segment diameter to that measured in vivo with split-detector AOSLO. Results. Nonconfocal split-detector AOSLO reveals the photoreceptor inner segment with or without the presence of a waveguiding outer segment. The diameter of inner segments measured in vivo is in good agreement with histology. A substantial number of foveal and parafoveal cone photoreceptors with apparently intact inner segments were identified in patients with the inherited disease achromatopsia. Conclusions. The application of nonconfocal split-detector to emerging human gene therapy trials will improve the potential of therapeutic success, by identifying patients with sufficient retained photoreceptor structure to benefit the most from intervention. Additionally, split-detector imaging may be useful for studies of other retinal degenerations such as AMD, retinitis pigmentosa, and choroideremia where the outer segment is lost before the remainder of the photoreceptor cell

    Distributive Justice for Volunteers: Extrinsic Outcome Distribution Matters

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    Volunteer organizations continue to suffer from turnover; the current volunteer rate is the lowest since 2002. Distributive justice, satisfaction, and extrinsic outcome importance were examined as influences of volunteer intention to quit. Survey results from 294 volunteers revealed that those who perceived less than fair distribution of extrinsic outcomes experienced heightened intention to quit compared to those who perceived fair distribution. Overall satisfaction partially mediated this relationship. We explored the potential moderating role of volunteers’ assessment of the importance of extrinsic outcomes on the overall mediated relationship

    Global Analysis of Fragmentation Functions for Eta Mesons

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    Fragmentation functions for eta mesons are extracted at next-to-leading order accuracy of QCD in a global analysis of data taken in electron-positron annihilation and proton-proton scattering experiments. The obtained parametrization is in good agreement with all data sets analyzed and can be utilized, for instance, in future studies of double-spin asymmetries for single-inclusive eta production. The Lagrange multiplier technique is used to estimate the uncertainties of the fragmentation functions and to assess the role of the different data sets in constraining them.Comment: 11 pages, 8 figures, updated reference

    Rapid analytical methods for the microalgal and cyanobacterial biorefinery: application on strains of industrial importance.

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    To realise the potential of microalgae in the biorefinery context, exploitation of multiple products is necessary for profitability and for bioproduct valorisation. Appropriate analytical tools are required for growth optimisation, culture monitoring and quality control purposes, with safe, low-tech and low-cost solutions favourable. Rapid, high-throughput and user-friendly methodologies were devised for a) determination phycobiliproteins, chlorophylls, carotenoids, proteins, carbohydrates and lipids and b) qualitative and quantitative carotenoid profiling using UPLC-PDA-MSE. The complimentary methods were applied on 11 commercially important microalgal strains including Prasinophytes, Haptophytes and cyanobacteria, highlighting the suitability of some strains for coproduct exploitation and the methods utility for research and industrial biotechnology applications. The UPLC method allowed separation of 41 different carotenoid compounds in < 15 minutes. Simple techniques are described for further quantification and comparison of pigment profiles, allowing for easy strain selection and optimisation for pigment production, with suitability for biotechnological or biomedical applications

    Probabilistic one-time programs using quantum entanglement

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    It is well known that quantum technology allows for an unprecedented level of data and software protection for quantum computers as well as for quantum-assisted classical computers. To exploit these properties, probabilistic one-time programs have been developed, where the encoding of classical software in small quantum states enables computer programs that can be used only once. Such self-destructing one-time programs facilitate a variety of new applications reaching from software distribution to one-time delegation of signature authority. Whereas first proof-of-principle experiments demonstrated the feasibility of such schemes, the practical applications were limited due to the requirement of using the software on-the-fly combined with technological challenges due to the need for active optical switching and a large amount of classical communication. Here we present an improved protocol for one-time programs that resolves major drawbacks of previous schemes, by employing entangled qubit pairs. This results in four orders of magnitude higher count rates as well the ability to execute a program long after the quantum information exchange has taken place. We demonstrate our protocol over an underground fiber link between university buildings in downtown Vienna. Finally, together with our implementation of a one-time delegation of signature authority this emphasizes the compatibility of our scheme with prepare-and-measure quantum internet networks

    Evaluation of Pediatric Manual Wheelchair Mobility Using Advanced Biomechanical Methods

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    There is minimal research of upper extremity joint dynamics during pediatric wheelchair mobility despite the large number of children using manual wheelchairs. Special concern arises with the pediatric population, particularly in regard to the longer duration of wheelchair use, joint integrity, participation and community integration, and transitional care into adulthood. This study seeks to provide evaluation methods for characterizing the biomechanics of wheelchair use by children with spinal cord injury (SCI). Twelve subjects with SCI underwent motion analysis while they propelled their wheelchair at a self-selected speed and propulsion pattern. Upper extremity joint kinematics, forces, and moments were computed using inverse dynamics methods with our custom model. The glenohumeral joint displayed the largest average range of motion (ROM) at 47.1° in the sagittal plane and the largest average superiorly and anteriorly directed joint forces of 6.1% BW and 6.5% BW, respectively. The largest joint moments were 1.4% body weight times height (BW × H) of elbow flexion and 1.2% BW × H of glenohumeral joint extension. Pediatric manual wheelchair users demonstrating these high joint demands may be at risk for pain and upper limb injuries. These evaluation methods may be a useful tool for clinicians and therapists for pediatric wheelchair prescription and training

    A Web-Based Intervention is Feasible for Supporting Weight Loss and Increased Activity in Rural Women with Arthritis

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    Rural women have well documented health disparities, with higher prevalence of obesity and chronic conditions, including arthritis. Change in weight and actigraph-recorded data were examined in a subset of 63 of 82 women with physician-diagnosed arthritis who completed a 30-month web-based clinical trial. Repeated measures analyses showed women lost weight from baseline to six months, slowly regained at 18 and 30 months, ending with a lower weight than baseline F(1,62)=40.89, p\u3c0.001, η2p =0.40. Of 53 women with complete data, activity increased at six months, decreased at 18 months, and increased at 30 months F(1,52)=4.14, p =.04, η2p=0.07. Women showed improved change in weight and activity from baseline at six, 18 and 30 months. This study adds support that web-based programs may promote weight loss and activity in a hard-to-reach, underserved population of midlife and older rural women with arthriti

    Exploring the impact of elevated depressive symptoms on the ability of a tailored asthma intervention to improve medication adherence among urban adolescents with asthma

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    BACKGROUND: In patients with asthma, medication adherence is a voluntary behavior that can be affected by numerous factors. Depression is an important co-morbidity in adolescents with asthma that may significantly impact their controller medication adherence and other asthma-related outcomes. The modifying effect of depressive symptoms on an asthma intervention’s ability to improve asthma controller medication adherence among urban adolescents with asthma has not yet been reported. OBJECTIVE: To assess self-reported symptoms of depression as an effect modifier of the relationship between randomization group and controller medication adherence at 6-month follow-up. METHODS: These analyses use data from a randomized controlled trial (RCT) conducted in Detroit high schools to evaluate a tailored asthma management program. The intervention included referrals to school or community resources for students reporting symptoms of depression and other issues. “Elevated depressive symptoms” was defined as a positive answer to ≥ 5 of 7 questions from a validated tool included on the baseline questionnaire. Self-reported adherence to controller medication was collected at intervention onset (session 1) and at 6-month follow up. Analyses were restricted to students with report of a controller medication at baseline. Logistic regression was used to assess elevated depressive symptoms as an effect modifier of the relationship between randomization group and 6-month adherence. RESULTS: Of the 422 students enrolled in the RCT, a controller medication was reported at intervention onset by n = 123 adolescents (29%). Analyzing this group, we observed an interaction between elevated depressive symptoms and adherence (p = 0.073). Stratified analysis showed better adherence in treatment group adolescents meeting criteria for elevated depressive symptoms at baseline as compared to the control group (adjusted Odds Ratio [aOR] = 9.50; p = 0.024). For adolescents without elevated depressive symptoms at baseline, differences in adherence by group assignment did not reach statistical significance (aOR 1.40, p = 0.49). CONCLUSIONS: In this sample of students reporting controller medications at baseline, report of elevated depressive symptoms at baseline and randomization to the intervention group was associated with significantly better adherence at 6-month follow up when compared to that of a control group. Larger studies are needed to evaluate the impact of depression on the relationship between adherence and asthma intervention effectiveness
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