7,512 research outputs found

    Mid-IR continuous-wave fiber-laser-pumped optical parametric oscillators

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    We review recent developments in continuous-wave mid-infrared optical parametric oscillators pumped by fiber lasers. Such devices are potentially valuable spectroscopic sources providing high output powers and rapid, wide-range tuning in the mid-infrared molecular fingerprint region

    Quantifying contextual contributions to word-recognition processes

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    Social media and information overload : survey results

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    A UK-based online questionnaire investigating aspects of usage of user-generated media (UGM), such as Facebook, LinkedIn and Twitter, attracted 587 participants. Results show a high degree of engagement with social networking media such as Facebook, and a significant engagement with other media such as professional media, microblogs and blogs. Participants who experience information overload are those who engage less frequently with the media, rather than those who have fewer posts to read. Professional users show different behaviours to social users. Microbloggers complain of information overload to the greatest extent. Two thirds of Twitter-users have felt that they receive too many posts, and over half of Twitter-users have felt the need for a tool to filter out the irrelevant posts. Generally speaking, participants express satisfaction with the media, though a significant minority express a range of concerns including information overload and privacy

    Metformin severely impairs in vivo muscle oxidative capacity in a rat model of type 2 diabetes

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    Objective: To investigate the effects of metformin on in vivo and in vitro skeletal muscle mitochondrial function in Zucker diabetic fatty (ZDF) rats using 31P magnetic resonance spectroscopy (MRS) and high-resolution respirometry (HRR), respectively. Methods: 12-week old healthy (fa/+) and diabetic (fa/fa) ZDF rats were treated with metformin (0, 30, 100 or 300 mg/kg body weight/day) for 15 days by oral gavage. At day 14, in vivo31P MRS was performed on the tibialis anterior (TA) muscle to measure PCr recovery. At day 15, animals were killed and TA muscles were excised for in vitro HRR measurements. Results: Metformin treatment decreased PCr recovery rates in a dose-dependent manner in both healthy fa/+ and diabetic fa/fa rats. Whereas, the clinical dose of 30 mg/kg/day had no significant effect, PCr recovery rates were ~22% and ~47% decreased at 100 and 300 mg/kg/day. HRR measurements showed a similar, but less pronounced effect of metformin on in vitro mitochondrial function

    Functional consequences of sphingomyelinase-induced changes in erythrocyte membrane structure.

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    Inflammation enhances the secretion of sphingomyelinases (SMases). SMases catalyze the hydrolysis of sphingomyelin into phosphocholine and ceramide. In erythrocytes, ceramide formation leads to exposure of the removal signal phosphatidylserine (PS), creating a potential link between SMase activity and anemia of inflammation. Therefore, we studied the effects of SMase on various pathophysiologically relevant parameters of erythrocyte homeostasis. Time-lapse confocal microscopy revealed a SMase-induced transition from the discoid to a spherical shape, followed by PS exposure, and finally loss of cytoplasmic content. Also, SMase treatment resulted in ceramide-associated alterations in membrane-cytoskeleton interactions and membrane organization, including microdomain formation. Furthermore, we observed increases in membrane fragility, vesiculation and invagination, and large protein clusters. These changes were associated with enhanced erythrocyte retention in a spleen-mimicking model. Erythrocyte storage under blood bank conditions and during physiological aging increased the sensitivity to SMase. A low SMase activity already induced morphological and structural changes, demonstrating the potential of SMase to disturb erythrocyte homeostasis. Our analyses provide a comprehensive picture in which ceramide-induced changes in membrane microdomain organization disrupt the membrane-cytoskeleton interaction and membrane integrity, leading to vesiculation, reduced deformability, and finally loss of erythrocyte content. Understanding these processes is highly relevant for understanding anemia during chronic inflammation, especially in critically ill patients receiving blood transfusions

    An exploration of the experiences and utility of functional electrical stimulation for foot drop in people with multiple sclerosis

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    Purpose: Functional electrical stimulation (FES) is effective in improving walking in people with multiple sclerosis (MS) with foot drop. There is limited research exploring people’s experiences of using this device. This study aims to explore the utility, efficacy, acceptability, and impact on daily life of the device in people with MS. Methods: An interpretative phenomenological approach was employed. Ten participants who had used FES for 12 months were interviewed. Transcripts were analysed, and emergent themes identified. Results: Nine participants continued to use the device. Three relevant super-ordinate themes were identified; impact of functional electrical stimulation, sticking with functional electrical stimulation, and autonomy and control. Participants reported challenges using the device; however, all reported positive physical and psychological benefits. Intrinsic and external influences such as; access to professional help, the influence of others, an individual’s ability to adapt, and experiences using the device, influenced their decisions to continue with the device. A thematic model of these factors was developed. Conclusions: This study has contributed to our understanding of people with MS experiences of using the device and will help inform prescribing decisions and support the continued, appropriate use of FES over the longer term
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