99 research outputs found
Optimization Study of Beam Position and Angular Jitter Independent Bunch Length Monitor for Awake Run 2
In this paper, a study using the Polarization Current Approach (PCA) model is performed to optimize the design of a short bunch length monitor using two dielectric radiators that produce coherent Cherenkov Diffraction Radiation (ChDR). The electromagnetic power emitted from each radiator is measuring a different part of the bunch spectrum using Schottky diodes. For various bunch lengths, the coherent ChDR spectrums are calculated to find the most suitable frequency bands for the detection system. ChDR intensities measured by each detector are estimated for different impact parameters to explore the dependence of bunch length monitor on beam position and angular jitter. It is found that, in the present configuration, the effects of beam position and angular jitter are negligibly small for bunch length measurement
Analytical and Numerical Characterization of Cherenkov Diffraction Radiation as a Longitudinal Electron Bunch Profile Monitor for AWAKE Run 2
In this paper, CST simulations of the coherent Cherenkov Diffraction Radiation with a range of parameters for different dielectric target materials and geometries are discussed and compared with the theoretical investigation of the Polarization Current Approach to design a prototype of a radiator for the bunch length/profile monitor for AWAKE Run 2. It was found that the result of PCA theory and CST simulation are consistent with each other regarding the shape of the emitted ChDR cone
Evaluation of CT vascularization patterns for survival prognosis in patients with hepatocellular carcinoma treated by conventional TACE
PURPOSE:Transarterial chemoembolization (TACE) is an established treatment for intermediate stage hepatocellular carcinoma (HCC). The aim of this retrospective study was to evaluate the power of lesion vascularization criteria based on computed tomography for prognosis of overall survival before initiation of treatment.METHODS:A total of 59 patients with intermediate stage HCC treated with TACE as first-line treatment were retrospectively evaluated. TACE procedures were performed using doxorubicin, cisplatin, and lipiodol. Response evaluation criteria in solid tumors version 1.1 (RECIST 1.1) were used to determine the initial tumor response. Four vascularization patterns (VP) of the largest target lesion (homogeneous vascularization [VP1], homogeneous vascularization with additional arterial hypervascularization [VP2], heterogeneous vascularization with [VP3] and without zones of hypervascularization [VP4]) were assessed prior to the first TACE and correlated to survival.RESULTS:Kaplan-Meier analysis yielded a median overall survival of 608 days (standard error [SE], 120.5 days). Survival analysis showed significant differences depending on the vascularization patterns (P = 0.012; hazard ratio, 0.327): patients with homogeneously vascularized lesions (VP1, VP2) had a median overall survival of 1091 days (SE, 235.5 days). Patients with heterogeneous vascularization of the lesion (VP3 and VP4) showed a median overall survival of 508 days (SE, 113.9 days).CONCLUSION:The vascularization pattern of the largest HCC lesion is helpful for survival prognosis under TACE treatment and therefore has the potential to be used as an additional parameter for treatment stratification
Extending the spectrum of Ellis van Creveld syndrome: a large family with a mild mutation in the EVC gene
<p>Abstract</p> <p>Background</p> <p>Ellis-van Creveld (EvC) syndrome is characterized by short limbs, short ribs, postaxial polydactyly, dysplastic nails and teeth and is inherited in an autosomal recessive pattern. We report a family with complex septal cardiac defects, rhizomelic limb shortening, and polydactyly, without the typical lip, dental, and nail abnormalities of EvC. The phenotype was inherited in an autosomal recessive pattern, with one instance of pseudodominant inheritance.</p> <p>Methods</p> <p>Because of the phenotypic overlap with EvC, microsatellite markers were used to test for linkage to the <it>EVC/EVC2 </it>locus. The results did not exclude linkage, so samples were sequenced for mutations.</p> <p>Results</p> <p>We identified a c.1868T>C mutation in <it>EVC</it>, which predicts p.L623P, and was homozygous in affected individuals.</p> <p>Conclusion</p> <p>We conclude that this <it>EVC </it>mutation is hypomorphic and that such mutations can cause a phenotype of cardiac and limb defects that is less severe than typical EvC. <it>EVC </it>mutation analysis should be considered in patients with cardiac and limb malformations, even if they do not manifest typical EvC syndrome.</p
Extending the spectrum of Ellis van Creveld syndrome: a large family with a mild mutation in the EVC gene
<p>Abstract</p> <p>Background</p> <p>Ellis-van Creveld (EvC) syndrome is characterized by short limbs, short ribs, postaxial polydactyly, dysplastic nails and teeth and is inherited in an autosomal recessive pattern. We report a family with complex septal cardiac defects, rhizomelic limb shortening, and polydactyly, without the typical lip, dental, and nail abnormalities of EvC. The phenotype was inherited in an autosomal recessive pattern, with one instance of pseudodominant inheritance.</p> <p>Methods</p> <p>Because of the phenotypic overlap with EvC, microsatellite markers were used to test for linkage to the <it>EVC/EVC2 </it>locus. The results did not exclude linkage, so samples were sequenced for mutations.</p> <p>Results</p> <p>We identified a c.1868T>C mutation in <it>EVC</it>, which predicts p.L623P, and was homozygous in affected individuals.</p> <p>Conclusion</p> <p>We conclude that this <it>EVC </it>mutation is hypomorphic and that such mutations can cause a phenotype of cardiac and limb defects that is less severe than typical EvC. <it>EVC </it>mutation analysis should be considered in patients with cardiac and limb malformations, even if they do not manifest typical EvC syndrome.</p
Development of the self-modulation instability of a relativistic proton bunch in plasma
Self-modulation is a beam–plasma instability that is useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing the ratio between the initial transverse size of the bunch and the plasma skin depth, the instability occurs later along the bunch, or not at all, over a fixed plasma length because the amplitude of the initial wakefields decreases. We show cases for which self-modulation does not develop, and we introduce a simple model discussing the conditions for which it would not occur after any plasma length. Changing bunch size and plasma electron density also changes the growth rate of the instability. We discuss the impact of these results on the design of a particle accelerator based on the self-modulation instability seeded by a relativistic ionization front, such as the future upgrade of the Advanced WAKefield Experiment
Phenotypic expansion in DDX3X - a common cause of intellectual disability in females
De novo variants in DDX3X account for 1-3% of unexplained intellectual disability (ID) cases and are amongst the most common causes of ID especially in females. Forty-seven patients (44 females, 3 males) have been described. We identified 31 additional individuals carrying 29 unique DDX3X variants, including 30 postnatal individuals with complex clinical presentations of developmental delay or ID, and one fetus with abnormal ultrasound findings. Rare or novel phenotypes observed include respiratory problems, congenital heart disease, skeletal muscle mitochondrial DNA depletion, and late-onset neurologic decline. Our findings expand the spectrum of DNA variants and phenotypes associated with DDX3X disorders
Simulation and experimental study of proton bunch self-modulation in plasma with linear density gradients
We present numerical simulations and experimental results of the self-modulation of a long proton bunch in a plasma with linear density gradients along the beam path. Simulation results agree with the experimental results reported [F. Braunmller, T. Nechaeva et al. (AWAKE Collaboration), Phys. Rev. Lett. 125, 264801 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.264801]: with negative gradients, the charge of the modulated bunch is lower than with positive gradients. In addition, the bunch modulation frequency varies with gradient. Simulation results show that dephasing of the wakefields with respect to the relativistic protons along the plasma is the main cause for the loss of charge. The study of the modulation frequency reveals details about the evolution of the self-modulation process along the plasma. In particular for negative gradients, the modulation frequency across time-resolved images of the bunch indicates the position along the plasma where protons leave the wakefields. Simulations and experimental results are in excellent agreement
Experimental study of extended timescale dynamics of a plasma wakefield driven by a self-modulated proton bunch
Plasma wakefield dynamics over timescales up to 800 ps, approximately 100 plasma periods, are studied
experimentally at the Advanced Wakefield Experiment (AWAKE). The development of the longitudinal
wakefield amplitude driven by a self-modulated proton bunch is measured using the external injection of
witness electrons that sample the fields. In simulation, resonant excitation of the wakefield causes plasma
electron trajectory crossing, resulting in the development of a potential outside the plasma boundary as
electrons are transversely ejected. Trends consistent with the presence of this potential are experimentally
measured and their dependence on wakefield amplitude are studied via seed laser timing scans and electron
injection delay scan
The clinical and genetic spectrum of autosomal-recessive TOR1A-related disorders.
In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later onset can, in the context of biallelic inheritance, cause devastating neurodevelopmental disorders and infantile or childhood-onset neurodegeneration. TOR1A-associated arthrogryposis multiplex congenita 5 (AMC5) is a rare neurodevelopmental disorder arising from biallelic variants in TOR1A, a gene that in the heterozygous state is associated to torsion dystonia-1 (DYT1 or DYT-TOR1A), an early-onset dystonia with reduced penetrance. While 15 individuals with TOR1A-AMC5 have been reported (less than 10 in detail), a systematic investigation of the full disease-associated spectrum has not been conducted. Here, we assess the clinical, radiological and molecular characteristics of 57 individuals from 40 families with biallelic variants in TOR1A. Median age at last follow-up was 3 years (0-24 years). Most individuals presented with severe congenital flexion contractures (95%) and variable developmental delay (79%). Motor symptoms were reported in 79% and included lower limb spasticity and pyramidal signs, as well as gait disturbances. Facial dysmorphism was an integral part of the phenotype, with key features being a broad/full nasal tip, narrowing of the forehead and full cheeks. Analysis of disease-associated manifestations delineated a phenotypic spectrum ranging from normal cognition and mild gait disturbance to congenital arthrogryposis, global developmental delay, intellectual disability, absent speech and inability to walk. In a subset, the presentation was consistent with fetal akinesia deformation sequence with severe intrauterine abnormalities. Survival was 71% with higher mortality in males. Death occurred at a median age of 1.2 months (1 week - 9 years) due to respiratory failure, cardiac arrest, or sepsis. Analysis of brain MRI studies identified non-specific neuroimaging features, including a hypoplastic corpus callosum (72%), foci of signal abnormality in the subcortical and periventricular white matter (55%), diffuse white matter volume loss (45%), mega cisterna magna (36%) and arachnoid cysts (27%). The molecular spectrum included 22 distinct variants, defining a mutational hotspot in the C-terminal domain of the Torsin-1A protein. Genotype-phenotype analysis revealed an association of missense variants in the 3-helix bundle domain to an attenuated phenotype, while missense variants near the Walker A/B motif as well as biallelic truncating variants were linked to early death. In summary, this systematic cross-sectional analysis of a large cohort of individuals with biallelic TOR1A variants across a wide age-range delineates the clinical and genetic spectrum of TOR1A-related autosomal-recessive disease and highlights potential predictors for disease severity and survival
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