1,061 research outputs found

    Proposal for an Optical Test of the Einstein Equivalence Principle

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    The Einstein Equivalence Principle (EEP) underpins all metric theories of gravity. Its key element is the local position invariance of non-gravitational experiments, which entails the gravitational red-shift. Precision measurements of the gravitational red-shift tightly bound violations of the EEP only in the fermionic sector of the Standard Model, however recent developments of satellite optical technologies allow for its investigation in the electromagnetic sector. Proposals exploiting light interferometry traditionally suffer from the first-order Doppler effect, which dominates the weak gravitational signal necessary to test the EEP, making them unfeasible. Here, we propose a novel scheme to test the EEP, which is based on a double large-distance optical interferometric measurement. By manipulating the phase-shifts detected at two locations at different gravitational potentials it is possible to cancel-out the first-order Doppler effect and observe the gravitational red-shift implied by the EEP. We present the detailed analysis of the proposal within the post-Newtonian framework and the simulations of the expected signals obtained by using two realistic satellite orbits. Our proposal to overcome the first-order Doppler effect in optical EEP tests is feasible with current technology.Comment: manuscript improve

    An integrated approach in a case of facioscapulohumeral dystrophy

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    BACKGROUND: Muscle fatigue, weakness and atrophy are basilar clinical features that accompany facioscapulohumeral dystrophy (FSHD) the third most common muscular dystrophy.No therapy is available for FSHD. CASE PRESENTATION: We describe the effects of 6mo exercise therapy and nutritional supplementation in a 43-year-old woman severely affected by FSHD. CONCLUSION: A mixed exercise program combined with nutritional supplementation can be safely used with beneficial effects in selected patients with FSHD

    Beta-blocker treatment guided by head-up tilt test in neurally mediated syncope

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    This study was an open-label, uncontrolled, dose-escalation trial of beta-blockers in patients with a history of syncope without warning or syncope resulting in trauma (malignant vasovagal syncope) who had positive head-up tilt test (HUT) responses, with or without isoproterenol infusion. Thirty patients (mean age, 37 +/- 21 years) with recurrent syncopal and near-syncopal episodes of unexplained origin in the previous year (6 +/- 14 syncopal episodes and 17 +/- 3 near-syncopes) underwent HUT for diagnostic purposes and for guiding prophylactic treatment. After patients were given a 10-minute rest in a recumbent position, rye performed an WT at 70 degrees for 25 minutes; if indicated, isoproterenol testing was performed at incremental dosages (dye steps at 10-minute intervals at 80 degrees), AU patients experienced syncope during HUT, 15 (50%) at baseline HUT and 15 (50%) during isoproterenol infusion (1 to 3 mu g/min; mean, 1.6 mu g/min). Sixteen syncopes were of vasodepressor type, 10 were mixed, and 4 were of cardioinhibitory type. After baseline HUT, betablocking drugs were prescribed to all patients as follows: 1 patient was given propranolol (160 mg daily), and 29 patients were given metoprolol (246 +/- 49 mg daily), with a dose titration period of 14 days. HUT was repeated after 3 weeks, and 24 patients (80%) had negative results (no syncope or anomalous responses). After further dosage adjustment of beta-blockers in nonresponders, a negative HUT was obtained in 28 patients (93%). Overall mean metoprolol daily dose was 262 +/- 60 mg (29 patients), and propranolol was administered at 160 mg daily in 1 patient. Thirteen patients (43%) reported side effects, none of which required drug withdrawal. At an average follow-up of 16 +/- 4 months, none of the patients experienced syncope, a statistically significant reduction. Moreover, a statistically significant reduction in the number of near-syncopal episodes was observed in comparison to the previous year. None of the patients discontinued treatment because of long-term side effects. Beta-blockers were well tolerated and achieved a high rate of efficacy, even in cardioinhibitory syncopes. In conclusion, in selected patients with malignant vasovagal syncope, treatment with metoprolol or propranolol at relatively high doses is feasible and, if guided by HUT results, is associated with a favorable outcome in terms of freedom from syncopal recurrences. Appropriate titration to achieve the full beta-blocking effect appears to be advisable

    Sintering and mechanical properties of β‐SiC powder obtained from waste tires

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    Plasma synthesized SiC powder obtained from quartz and carbonaceous residue of waste tires was successfully sintered at 1925 ℃ by pressureless liquid-phase method using yttria and alumina as sintering aids (T-SiC). Comparison with sintered SiC obtained from commercial powder (C-SiC) put in evidence of similar sintered density (98%T.D.), but much finer microstructure of T-SiC than that of C-SiC. T-SiC also showed higher flexural strength than C-SiC both at room temperature (508 vs. 458 MPa) and at 1500 ℃ (280 vs. 171 MPa). Difference in liquid phase was responsible for the differences in hardness and fracture toughness. The high value of the Young's modulus of T-SiC (427 MPa) confirmed the high degree of sinterability of this powder and that it can be a promising candidate for structural applications with high added value. © 2016, The Author(s)

    Different FDG-PET metabolic patterns at single-subject level in the behavioral variant of fronto-temporal dementia.

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    BACKGROUND: The diagnosis of probable behavioral variant of fronto-temporal dementia (bvFTD) according to current criteria requires the imaging evidence of frontal and/or anterior temporal atrophy or hypoperfusion/hypometabolism. Different variants of this pattern of brain involvement may, however, be found in individual cases, supporting the presence of heterogeneous phenotypes. OBJECTIVE: We examined in a case-by-case approach the FDG-PET metabolic patterns of patients fulfilling clinical criteria for probable bvFTD, assessing the presence and frequency of specific FDG-PET features. MATERIALS AND METHODS: Fifty two FDG-PET scans of probable bvFTD patients were retrospectively analyzed together with clinical and neuropsychological data. Neuroimaging experts rated the FDG-PET hypometabolism maps obtained at the single-subject level with optimized voxel-based Statistical Parametric Mapping (SPM). The functional metabolic heterogeneity was further tested by hierarchical cluster analysis and principal component analysis (PCA). RESULTS: Both the SPM maps and cluster analysis identified two major variants of cerebral hypometabolism, namely the "frontal" and the "temporo-limbic", which were correlated with different cognitive profiles. Executive and language deficits were the cognitive hallmark in the "frontal" subgroup, while poor encoding and recall on long-term memory tasks was typical of the "temporo-limbic" subgroup. DISCUSSION: SPM single-subject analysis indicates distinct patterns of brain dysfunction in bvFTD, coupled with specific clinical features, suggesting different profiles of neurodegenerative vulnerability. These findings have important implications for the early diagnosis of bvFTD and for the application of the recent international consensus criteria

    Functionalized Hyaluronic Acid for “In Situ” Matrix Metalloproteinase Inhibition: A Bioactive Material to Treat the Dry Eye Sydrome

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    Hyaluronic acid (HA) is a naturally occurring polysaccharide with many molecular functions, including maintaining the structure and physiology of the tissues, tissue remodeling, and inflammation. HA is found naturally in physiological tear fluid, possesses excellent mucus-layer-adhesive properties, and is successfully employed in the treatment of dry eye syndrome (DES). However, HA has as major drawback: its rapid in vivo degradation by hyaluronidase. We report on a unique material, namely, HA-3, obtained by the functionalization of HA with the metalloproteinase inhibitor 3 (MMPI). This material is characterized by an increased resistance to hyaluronidase degradation, associated with MMP inhibition properties. The ability of HA-3 to prevent dehydration of human corneal epithelial cells in vitro and in vivo may accelerate the development of more efficient DES treatment and broaden the application of HA in human diseases

    Current models of care for the management of HIV patients with comorbidities in England: a survey

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    Introduction: The number of people aged ]50 living with HIV in the UK is rapidly increasing. Effective treatment means HIV is usually well controlled; however, there has been an increase in individuals experiencing comorbid conditions associated with ‘‘normal’’ ageing. This aim of this study was to find out what models of care are currently in place for the management of patients with comorbidities. Materials and methods: A link to an online questionnaire was sent via the British HIV Association (BHIVA) Audit Committee to one HIV clinician in each HIV unit in England. Results: Forty-four units responded. Only 11 units (25%) provided specialized clinics for the management of comorbidities. These included: 1) Specialist clinics for the management of a non-infectious comorbidity (any age) e.g. a liver or renal clinic (n10). These clinics utilized in-person appointments (n3), or a combination of virtual and in-person appointments (n7). They were managed by an HIV clinician and non-HIV clinician together (n8), HIV clinician with an interest in the specialist area (n4) or specialist with an interest in HIV (n4). 2) Services for HIV patients with multiple comorbidities (any age) (n2). 3) Dedicated clinics for older people (n5) with eligibility determined by age (]50 years) or the presence of a comorbidity. Additionally, two HIV units employed a GP on site and two had set up a locally enhanced service providing enhanced primary care for HIV-positive patients. Six HIV units ran nurse-led clinics for patients with comorbid conditions. Co-ordination of care for patients with comorbid conditions was conducted by an HIV specialist doctor (n27), the patient’s GP (n18), HIV specialist nurse (n11) or the patient themselves (n9). Eleven clinics reported using case management for patients with multiple comorbid conditions. Self-management support (e.g. nurse-led or as part of an expert patient programme) for patients with comorbid conditions was provided at 18 HIV units. Conclusions: Only a quarter of the clinics surveyed had set up clinics for the management of comorbidities in people living with HIV. While a variety of different approaches were used, services were usually focused on the management of one comorbidity, and few provided services for multiple comorbidities. This is an increasing priority in the context of an ageing population. P162 Th
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