229 research outputs found

    Muon-spin-rotation measurements of the penetration depth in Li_2Pd_3B

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    Measurements of the magnetic field penetration depth λ\lambda in the ternary boride superconductor Li2_2Pd3_3B (Tc7.3T_c\simeq7.3 K) have been carried out by means of muon-spin rotation (μ\muSR). The absolute values of λ\lambda, the Ginzburg-Landau parameter κ\kappa, and the first Hc1H_{c1} and the second Hc2H_{c2} critical fields at T=0 obtained from μ\muSR were found to be λ(0)=252(2)\lambda(0)=252(2) nm, κ(0)=27(1)\kappa(0)=27(1), μ0Hc1(0)=9.5(1)\mu_0H_{c1}(0)=9.5(1) mT, and μ0Hc2(0)=3.66(8)\mu_0H_{c2}(0)=3.66(8) T, respectively. The zero-temperature value of the superconducting gap Δ0=\Delta_0=1.31(3) meV was found, corresponding to the ratio 2Δ0/kBTc=4.0(1)2\Delta_0/k_BT_c=4.0(1). At low temperatures λ(T)\lambda(T) saturates and becomes constant below T0.2TcT\simeq 0.2T_c, in agreement with what is expected for s-wave BCS superconductors. Our results suggest that Li2_2Pd3_3B is a s-wave BCS superconductor with the only one isotropic energy gap.Comment: 6 pages, 7 figure

    Study of the magnetic penetration depth in RbOs_2O_6

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    Measurements of the magnetic field penetration depth \lambda in the pyrochlore superconductor RbOs_2O_6 (T_c\simeq6.3 K) were carried out by means of the muon-spin-rotation (\muSR) technique. At low temperatures \lambda^{-2}(T) saturates and becomes constant below T\simeq 0.2T_c, in agreement with what is expected for weak-coupled s-wave BCS superconductors. The value of \lambda at T=0 was found to be in the range of 250 nm to 300 nm. \muSR and equilibrium magnetization measurements both reveal that at low temperatures λ\lambda is almost (at the level of 10%) independent of the applied magnetic field. This result suggests that the superconducting energy gap in RbOs_2O_6 is isotropic.Comment: 8 pages, 9 figure

    Pressure effects on the transition temperature and the magnetic field penetration depth in the pyrochlore superconductor RbOs_2O_6

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    We report magnetization measurements under high hydrostatic pressure in the newly discovered pyrochlore superconductor RbOs_2O_6 (T_c\simeq6.3K at p=0). A pronounced and {\it positive} pressure effect (PE) on T_c with dT_c/dp =0.090(1)K/kbar was observed, whereas no PE on the magnetic penetration depth \lambda was detected. The relative pressure shift of T_c [ dlnT_c/dp \simeq 1.5%/kbar] is comparable with the highest values obtained for highly underdoped high-temperature cuprate superconductors. Our results suggest that RbOs_2O_6 is an adiabatic BCS-type superconductor.Comment: 11 pages, 4 figure

    Embolic strokes of undetermined source: prevalence and patient features in the ESUS Global Registry

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    Background: Recent evidence supports that most non-lacunar cryptogenic strokes are embolic. Accordingly, these strokes have been designated as embolic strokes of undetermined source (ESUS). Aims: We undertook an international survey to characterize the frequency and clinical features of ESUS patients across global regions. Methods: Consecutive patients hospitalized for ischemic stroke were retrospectively surveyed from 19 stroke research centers in 19 different countries to collect patients meeting criteria for ESUS. Results: Of 2144 patients with recent ischemic stroke, 351 (16%, 95% CI 15% to 18%) met ESUS criteria, similar across global regions (range 16% to 21%), and an additional 308 (14%) patients had incomplete evaluation required for ESUS diagnosis. The mean age of ESUS patients (62 years; SD = 15) was significantly lower than the 1793 non-ESUS ischemic stroke patients (68 years, p ≤ 0.001). Excluding patients with atrial fibrillation (n = 590, mean age = 75 years), the mean age of the remaining 1203 non-ESUS ischemic stroke patients was 64 years (p = 0.02 vs. ESUS patients). Among ESUS patients, hypertension, diabetes, and prior stroke were present in 64%, 25%, and 17%, respectively. Median NIHSS score was 4 (interquartile range 2–8). At discharge, 90% of ESUS patients received antiplatelet therapy and 7% received anticoagulation. Conclusions: This cross-sectional global sample of patients with recent ischemic stroke shows that one-sixth met criteria for ESUS, with additional ESUS patients likely among those with incomplete diagnostic investigation. ESUS patients were relatively young with mild strokes. Antiplatelet therapy was the standard antithrombotic therapy for secondary stroke prevention in all global regions

    Long-term effects of a multidisciplinary treatment of uncomplicated obesity on carotid intima-media thickness

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    Obesity is associated with well-known cardiovascular risk factors and a lower life expectancy. This study investigated whether nonoperative nutritional treatment of obesity without comorbidities influenced the carotid intima-media thickness (c-IMT) in the long run. Fifty-four subjects of an original cohort of 251 subjects were re-evaluated 10 years after a medical nutritional treatment (MNT) with cognitive-behavioral approach for uncomplicated obesity. Forty subjects were classified as failure (10-year body weight change >0.5 kg) and 14 (body weight change 640.5 kg) as a success of the MNT. Ten years after MNT, c-IMT significantly increased (0.06 \ub1 0.02 mm; P = 0.004) in the failure group and significantly decreased ( 120.07 \ub1 0.03 mm; P = 0.027) in the success group. Ten-year change in c-IMT correlated significantly with 10-year change in body weight (r = 0.28; P = 0.040). Multiple stepwise linear regression analysis demonstrated that age, final BMI, and group (success or failure) influenced independently the 10-year c-IMT. In conclusion, this study is in agreement with the possibility that the successful MNT of obesity may be an effective choice in the long run and seems to indicate that it may be able to reduce the cardiovascular risk as reflected by the change in c-IMT

    The World Association against Infection in Orthopaedics and Trauma (WAIOT) procedures for Microbiological Sampling and Processing for Periprosthetic Joint Infections (PJIs) and other Implant-Related Infections

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    While implant-related infections continue to play a relevant role in failure of implantable biomaterials in orthopaedic and trauma there is a lack of standardised microbiological procedures to identify the pathogen(s). The microbiological diagnosis of implant-related infections is challenging due to the following factors: the presence of bacterial biofilm(s), often associated with slow-growing microorganisms, low bacterial loads, previous antibiotic treatments and, possible intra-operative contamination. Therefore, diagnosis requires a specific set of procedures. Based on the Guidelines of the Italian Association of the Clinical Microbiologists (AMCLI), the World Association against Infection in Orthopaedics and Trauma has drafted the present document. This document includes guidance on the basic principles for sampling and processing for implant-related infections based on the most relevant literature. These procedures outline the main microbiological approaches, including sampling and processing methodologies for diagnostic assessment and confirmation of implant-related infections. Biofilm dislodgement techniques, incubation time and the role of molecular approaches are addressed in specific sections. The aim of this paper is to ensure a standardised approach to the main microbiological methods for implant-related infections, as well as to promote multidisciplinary collaboration between clinicians and microbiologists

    Countering the Australian 'ndrangheta: The criminalisation of mafia behaviour in Australia between national and comparative criminal law

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    Mafia-type criminal groups belonging to, or originated from, the Calabrian ‘ndrangheta from Southern Italy, have been object of recent academic research and media attention in Australia. The Australian ‘ndrangheta, as qualified form of organised crime, poses new challenges for law enforcement in the country. This paper briefly looks at the strategies to fight organised crime in Australia, with specific focus on anti-association laws. By using a comparative approach, the paper will look at the criminalisation of mafias as qualified forms of organised crime in other two jurisdictions, Italy and the USA, to advocate for an effective mafia criminalisation in Australia. In conclusion, this paper will argue that, in order to also fight mafia phenomena, criminal law in Australia should focus on behaviours of organised crime groups rather than only on the criminalisation of proscribed associations and their illegal activities

    Jacobsen syndrome

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    Jacobsen syndrome is a MCA/MR contiguous gene syndrome caused by partial deletion of the long arm of chromosome 11. To date, over 200 cases have been reported. The prevalence has been estimated at 1/100,000 births, with a female/male ratio 2:1. The most common clinical features include pre- and postnatal physical growth retardation, psychomotor retardation, and characteristic facial dysmorphism (skull deformities, hypertelorism, ptosis, coloboma, downslanting palpebral fissures, epicanthal folds, broad nasal bridge, short nose, v-shaped mouth, small ears, low set posteriorly rotated ears). Abnormal platelet function, thrombocytopenia or pancytopenia are usually present at birth. Patients commonly have malformations of the heart, kidney, gastrointestinal tract, genitalia, central nervous system and skeleton. Ocular, hearing, immunological and hormonal problems may be also present. The deletion size ranges from ~7 to 20 Mb, with the proximal breakpoint within or telomeric to subband 11q23.3 and the deletion extending usually to the telomere. The deletion is de novo in 85% of reported cases, and in 15% of cases it results from an unbalanced segregation of a familial balanced translocation or from other chromosome rearrangements. In a minority of cases the breakpoint is at the FRA11B fragile site. Diagnosis is based on clinical findings (intellectual deficit, facial dysmorphic features and thrombocytopenia) and confirmed by cytogenetics analysis. Differential diagnoses include Turner and Noonan syndromes, and acquired thrombocytopenia due to sepsis. Prenatal diagnosis of 11q deletion is possible by amniocentesis or chorionic villus sampling and cytogenetic analysis. Management is multi-disciplinary and requires evaluation by general pediatrician, pediatric cardiologist, neurologist, ophthalmologist. Auditory tests, blood tests, endocrine and immunological assessment and follow-up should be offered to all patients. Cardiac malformations can be very severe and require heart surgery in the neonatal period. Newborns with Jacobsen syndrome may have difficulties in feeding and tube feeding may be necessary. Special attention should be devoted due to hematological problems. About 20% of children die during the first two years of life, most commonly related to complications from congenital heart disease, and less commonly from bleeding. For patients who survive the neonatal period and infancy, the life expectancy remains unknown
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