1,245 research outputs found

    Direct observation of the high magnetic field effect on the Jahn-Teller state in TbVO4

    Get PDF
    We report the first direct observation of the influence of high magnetic fields on the Jahn-Teller (JT) transition in TbVO4. Contrary to spectroscopic and magnetic methods, X-ray diffraction directly measures the JT distortion; the splitting between the (311)/(131) and (202)/(022) pairs of Bragg reflections is proportional to the order parameter. Our experimental results are compared to mean field calculations, taking into account all possible orientations of the grains relative to the applied field, and qualitative agreement is obtained.Comment: 11 pages, 4 figures, submitted to Phys. Rev. Let

    Mutation of the parkinsonism gene ATP13A2 causes neuronal ceroid-lipofuscinosis

    Get PDF
    Neuronal ceroid lipofuscinoses (NCLs) comprise a heterogeneous group of metabolic storage diseases that present with the accumulation of autofluorescent lipopigment, neurodegeneration and premature death. Nine genes have been thus far identified as the cause of different types of NCL, with ages at onset ranging from around birth to adult, although the underlying etiology of the disease still remains elusive. We present a family with typical NCL pathology in which we performed exome sequencing and identified a single homozygous mutation in ATP13A2 that fully segregates with disease within the family. Mutations in ATP13A2 are a known cause of Kufor–Rakeb syndrome (KRS), a rare parkinsonian phenotype with juvenile onset. These data show that NCL and KRS may share etiological features and implicate the lysosomal pathway in Parkinson's disease

    Addressing decision making for remanufacturing operations and design-for-remanufacture

    Get PDF
    Remanufacturing is a process of returning a used product to at least original equipment manufacturer original performance specification from the customers' perspective and giving the resultant product a warranty that is at least equal to that of a newly manufactured equivalent. This paper explains the need to combine ecological concerns and economic growth and the significance of remanufacturing in this. Using the experience of an international aero-engine manufacturer it discusses the impact of the need for sustainable manufacturing on organisational business models. It explains some key decision-making issues that hinder remanufacturing and suggests effective solutions. It presents a peer-validated, high-level design guideline to assist decision-making in design in order to support remanufacturing. The design guide was developed in the UK through the analysis of selections of products during case studies and workshops involving remanufacturing and conventional manufacturing practitioners as well as academics. It is one of the initial stages in the development of a robust design for remanufacture guideline

    Evaluation of the efficacy of endovascular treatment of pelvic congestion syndrome

    Get PDF
    AbstractAimTo assess the efficacy of venous embolization treatment for the pelvic congestion syndrome (PCS).Patients and methodsRetrospective study of 33 female patients undergoing pelvic venous embolization between January 2008 and May 2012 in Bordeaux. The inclusion criteria were clinical symptoms of PCS documented by transabdominal Doppler ultrasound and/or pelvic magnetic resonance imaging. Patients with pelvic varicose veins feeding saphenous varicose veins were excluded. The efficacy of treatment was assessed on a Visual Analog Scale (VAS).ResultsThirty-three patients were included and the mean follow up period was 26months (3–59months). The VAS was 7.37 (standard deviation: 0.99) before embolization and 1.36 (standard deviation: 1.73) after embolization (P<0.0001). Twenty patients reported that their symptoms had completely disappeared, 11 had partially disappeared and two had gained no improvement. A significant fall was found in the number of patients with dyspareunia (P<0.0001). A single technical embolization failure was reported.ConclusionOur series demonstrates the efficacy of embolization treatment with a significant fall in the VAS in patients with PCS

    A combined SAXS/WAXS investigation of the phase behaviour of di-polyenoic membrane lipids

    Get PDF
    AbstractReal-time measurements of the SAXS/WAXS diffraction patterns of aqueous dispersions (1:1 wt/wt) of the di-polyenoic lipids di-18:2 PC, di-18:3 PC, di-18:2 PE and di-18:3 PE were made over the temperature range 10° to about −80°C. The results of these measurements were compared to similar measurements performed on the corresponding di-18:0 and di-18:1 derivatives. SAXS measurements of the temperature dependence of lamellar repeat distances show that the di-polyenoic lipids undergo broad second-order transitions between their gel and liquid-crystal lamellar phases spanning 30–40°C. The di-18:1 and di-18:0 derivatives, in contrast, undergo abrupt first-order transitions. The gel phases of the di-18:0 derivatives are characterised by two-component WAXS patterns with a sharp component close to 0.42 nm and a broader component at narrower spacings. On cooling, these lipids appear to undergo an initial transition to an LÎČ, phase followed by a conversion to an Lc phase. The gel phases of the di-18:1 derivatives also show two-component patterns but with the sharp component centred closer to 0.44 nm. The di-polyenoic lipids, in contrast, are characterised by a single broad peak centred at a spacing of about 0.42 nm, close to that of conventional LÎČ, phases. The changes in lamellar repeat distance accompanying the transitions in the di-monoenoic and di-polyenoic lipids, all of which occur in the frozen state, are very similar, indicating that the acyl chains of the polyenoic lipids are close to their maximum extension in the gel state. The WAXS patterns of the polyenoic lipids suggest that the saturated upper parts of the acyl chains are packed on a regular hexagonal lattice while their polyunsaturated termini remain relatively disordered

    RARS2 mutations in a sibship with infantile spasms

    Get PDF
    Pontocerebellar hypoplasia is a group of heterogeneous neurodevelopmental disorders characterized by reduced volume of the brainstem and cerebellum. We report two male siblings who presented with early infantile clonic seizures, and then developed infantile spasms associated with prominent isolated cerebellar hypoplasia/atrophy on magnetic resonance imaging (MRI). Using whole exome sequencing techniques, both were found to be compound heterozygotes for one previously reported and one novel mutation in the gene encoding mitochondrial arginyl-tRNA synthetase 2 (RARS2). Mutations in this gene have been classically described in pontocerebellar hypoplasia type six (PCH6), a phenotype characterized by early (often intractable) seizures, profound developmental delay, and progressive pontocerebellar atrophy. The electroclinical spectrum of PCH6 is broad and includes a number of seizure types: myoclonic, generalized tonic-clonic, and focal clonic seizures. Our report expands the characterization of the PCH6 disease spectrum and presents infantile spasms as an associated electroclinical phenotype

    Determinants of delay in the head and neck oncology care pathway:The next step in value-based health care

    Get PDF
    Objective Head and neck squamous cell carcinomas (HNSCC) are relatively fast-growing tumours, and delay of treatment is associated with tumour progression and adverse outcomes. The aim of this study is to identify determinants of delay in a head and neck oncology centre. Methods This cohort study with prospectively collected data investigated associations between patient (including geriatric assessment at first consultation), tumour and treatment characteristics and treatment delay. Two quality indicator intervals assessing value-based healthcare were studied: care pathway interval (CPI, interval between first visit in an HNOC and treatment initiation) and time-to-treatment initiation (TTI, interval between histopathological confirmation of HNSCC and treatment initiation), using regression analyses. Results Stage-IV tumours and initial radiotherapy were independent predictors of delay in CPI. Initial radiotherapy was associated with delay in TTI. Overall, 37% of the patients started treatment within 30 days after first consultation (67% in case of initial surgical treatment and 11.5% if treated with (chemo)radiation, p <0.001). Geriatric assessment outcomes were not associated with delay. Indicators for delay in initial surgery patients were stage-IV tumours (CPI). Conclusion The majority of HNSCC patients encounter delay in treatment initiation, specifically in patients with advanced-stage tumours or when radiotherapy is indicated

    A phenotype of atypical apraxia of speech in a family carrying SQSTM1 mutation.

    Get PDF
    SQSTM1 mutations, coding for the p62 protein, were identified as a monogenic cause of Paget disease of bone and of amyotrophic lateral sclerosis. More recently, SQSTM1 mutations were identified in few families with frontotemporal dementia. We report a new family carrying SQSTM1 mutation and presenting with a clinical phenotype of speech apraxia or atypical behavioral disorders, associated with early visuo-contructional deficits. This study further supports the implication of SQSTM1 in frontotemporal dementia, and enlarges the phenotypic spectrum associated with SQSTM1 mutations

    Tuning of the size and the lattice parameter of ion-beam synthesized Pb nanoparticles embedded in Si

    Get PDF
    The size and lattice constant evolution of Pb nanoparticles (NPs) synthesized by high fluence implantation in crystalline Si have been studied with a variety of experimental techniques. Results obtained from small-angle x-ray scattering showed that the Pb NPs grow with increasing implantation fluence and annealing duration. The theory of NP growth kinetics can be applied to qualitatively explain the size evolution of the Pb NPs during the implantation and annealing processes. Moreover, the lattice constant of the Pb NPs was evaluated by conventional x-ray diffraction. The lattice dilatation was observed to decrease with increasing size of the Pb NPs. Such lattice constant tuning can be attributed to the pseudomorphism caused by the lattice mismatch between the Pb NPs and the Si matrix

    Energy-Dissipation, Runoff Production, and the 3-Dimensional Structure of River Basins

    Get PDF
    Three principles of optimal energy expenditure are used to derive the most important structural characteristics observed in drainage networks: (1) the principle of minimum energy expenditure in any link of the network, (2) the principle of equal energy expenditure per unit area of channel anywhere in the network, and (3) the principle of minimum total energy expenditure in the network as a whole. Their joint application results in a unified picture of the most important empirical facts which have been observed in the dynamics of the network and its three-dimensional structure. They also link the process of runoff production in the basin with the characteristics of the network
    • 

    corecore