The interconnections between Large Hadron Collider (LHC) main dipole and quadrupole magnets are made of soldered joints of two superconducting cables stabilized by a copper bus bar. The 2008 incident ...revealed the possible presence of defects in the interconnections of the 13 kA circuits that could lead to unprotected resistive transitions. Since then thorough experimental and numerical investigations were undertaken to determine the safe operating conditions for the LHC. This paper reports the analysis of experimental tests reproducing defective interconnections between main quadrupole magnets. A thermo-electromagnetic model was developed taking into account the complicated sample geometry. Close attention was paid to the physical description of the heat transfer towards helium, one of the main unknown parameters. The simulation results are reported in comparison with the measurements in case of static He I cooling bath. The outcome of this study constitutes a useful input to improve the stability assessment of the 13 kA bus bars interconnections.
Objectives
In the last decade, increasing evidence suggests a key role of adenosine in Parkinson's disease (PD) and A2A adenosine receptors (A2AARs) as an important pharmacological target in PD. An ...overexpression of A2AARs has been found in putamen and in peripheral blood cells of PD patients. The primary aim of this study was to verify whether the alterations in A2AARs in lymphocytes of PD subjects correlate with disease severity.
Material and methods
A consecutive sample of PD patients was enrolled. A clinical examination and a face‐to‐face interview were carried out. A2AARs were investigated to verify the affinity and receptor density in lymphocyte membranes. The data were compared with those found in healthy controls. Moreover, the correlation between A2AAR density and affinity and clinical variables was evaluated in PD patients.
Results
In human lymphocyte membranes from PD patients, an increase in A2AAR density and a decrease in A2AAR affinity were found if compared with healthy subjects. A statistically significant correlation between the A2AAR density or affinity and specific clinical parameters as motor and cognitive impairment was detected. Patients with higher A2AAR density and lower affinity were more likely to exhibit motor complications.
Conclusions
Parkinson's disease patients show an A2AAR upregulation in lymphocyte membranes if compared with healthy subjects. The correlation found between A2AAR density or affinity and clinical parameters highlights the central role of A2AAR modulation in the pharmacological treatment for PD and could suggest the putative role of A2AAR as a candidate biomarker of PD severity.
The commissioning and the exploitation of the LHC require a good knowledge of the stability margins of the superconducting magnets with respect to beam induced heat depositions. Previous studies ...showed that simple numerical models are suitable to carry out stability calculations of multi-strands cables, and highlighted the relevance of the heat transfer model with the surrounding helium. In this paper we present a systematic scan of the stability margin of all types of LHC cables working at 1.9 K against transient heat depositions. We specifically discuss the dependence of the stability margin on the parameters of the model, which provide an estimate of the uncertainty of the values quoted. The stability margin calculations have been performed using a zero-dimensional (0-D) numerical model, and a cooling model taking into account the relevant helium phases which may appear during a stability experiment: it includes Kapitza thermal resistance in superfluid He, boundary layer formation and heat transfer in He I, and considers the transition from nucleating boiling to film boiling during He gas formation.
The Coolant Purification Systems (CPSs) is one of the most relevant ancillary systems of European Helium Cooled Lead Lithium (HCLL) and Helium Cooled Pebble Bed (HCPB) Test Blanket Modules (TBMs) ...which are currently in the preliminary design phase in view of their installation and operation in ITER.
The CPS implements mainly two functions: the extraction and concentration of the tritium permeated from the TBM modules into the primary cooling circuit and the chemistry control of helium primary coolant.
During the HCLL and HCPB-TBSs (Test Blanket Systems) Conceptual Design Review (CDR) in 2015 it was recognized the need of reducing the tritium permeation into the Port Cell #16 of ITER. To achieve this and, then, to lower the tritium partial pressure in the Helium Cooling Systems in normal operation, the helium flow-rate treated by each CPS has been increased of almost one order of magnitude.
In 2017, to satisfy the CDR outcomes and the new design requirements requested by Fusion for Energy (F4E, the European Domestic Agency for ITER), ENEA performed a preliminary design of the “enhanced” CPSs.
This paper presents the current design of the “enhanced” CPSs, focusing on design requirements, assumptions, selection of technologies and preliminary components sizing.
In Parkinson’s disease (PD), the effects of deep brain stimulation of the pedunculopontine nucleus (PPTg-DBS) on gait has been object of international debate. Some evidence demonstrated that, in the ...late swing-early stance phase of gait cycle, a reduced surface electromyographic activation (sEMG) of tibialis anterior (TA) is linked to the striatal dopamine deficiency in PD patients. In the present study we report preliminary results on the effect of PPTg-DBS on electromyographic patterns during gait in individual PD patients. To evaluate the sEMG amplitude of TA, the root mean square (RMS) of the TA burst in late swing-early stance phase (RMS-A) was normalized as a percent of the RMS of the TA burst in late stance-early swing (RMS-B). We studied three male patients in the following conditions: on PPTg-DBS/on
l
-dopa, on PPTg-DBS/off
l
-dopa, off PPTg-DBS/on
l
-dopa, off PPTg-DBS/off
l
-dopa. For each assessment the UPDRS III was filled in. We observed no difference between on PPTg-DBS/off
l
-dopa and off PPTg-DBS/off
l
-dopa in UPDRS III scores. In off PPTg-DBS/off
l
-dopa, patient A (right implant) showed absence of the right and left RMSA, respectively, in 80% and 83% of gait cycles. Patient B (right implant) showed absence of the right RMS-A in 86% of cycles. RMS-A of the patient C (left implant) was bilaterally normal. In on PPTg- DBS/off
l
-dopa, no patient showed reduced RMS-A. Although the very low number of subjects we evaluated, our observations suggest that PPTg plays a role in modulating TA activation pattern during the steady state of gait.
The next generation of superconducting magnets for the interaction regions of particle colliders, as well as for fast cycled accelerators, will be confronted with large heat loads. In order to ...improve the evacuation of heat from the Nb-Ti coil towards He-II bath, a porous (enhanced) all-polyimide cable insulation scheme was proposed recently. The first results were promising, featuring a larger permeability to helium with respect to existing schemes under low compressive stress. In this paper we present an extended experimental study of heat transfer through the Enhanced Insulation into He-II bath, and comparison to the standard LHC insulation, at different levels of applied pressure. The thermal coupling between adjacent cables was investigated, as well as the impact of a localized heat deposition versus a distributed one. The results of this study show that, up to high pressure levels, the enhanced insulation scheme can provide a major improvement of heat transfer compared to the standard scheme used in the main LHC magnets.
Background: The cytokine interferon beta (IFN beta ) is successfully used in the treatment of multiple sclerosis (MS), although there is a high degree of variability in the response. A common ...mechanism involved in the modulation of responsiveness to cytokines is represented by regulation of their receptor expression through autocrine ligand-mediated loops. The present study is aimed at investigating the regulation of IFN alpha / beta receptor (IFNAR) during IFN beta therapy in patients with MS and at correlating it with the biologic responsiveness to the cytokine. Methods: Quantitative PCR measurements of IFNAR-1 and the three IFNAR-2 isoforms were performed in 141 patients after short-term and long-term treatment. Patients were also regularly screened for anti-IFN beta neutralizing antibodies (NAbs). IFN-inducible myxovirus resistance protein A messenger RNA was used as an indicator of bioactivity. Results: Pretreatment levels of IFNAR-2 in patients were lower overall than in controls (p = 0.038), and high levels correlated with greater bioactivity. Upon prolonged treatment, NAb-negative patients displayed a state of decreased transmembrane IFNAR-2 expression (p less than or equal to 0.025), whereas levels of soluble IFNAR-2 were slightly increased (p < 0.0001). The presence of NAbs reversed these effects (p less than or equal to 0.0056). In NAb-positive patients, pretreatment expression levels of both transmembrane IFNAR-2 isoforms were significantly lower than in NAb-negative patients (p less than or equal to 0.0089). Conclusions: Findings show that interferon- alpha / beta receptor (IFNAR)-2 isoforms are important regulators of the responsiveness to endogenous and systemically administered interferon beta (IFN beta ). They show a dual action, agonistic and antagonistic, that influences both the magnitude and the nature of the biologic response to IFN beta . Levels of IFNAR-2 are regulated with the aim of keeping the body in a state of equilibrium, even when nonphysiologic stimuli are present.
Our objective was to verify and expand previous evidence of psychometric inadequacies in the ALSFRS-R, in a different sample of subjects suffering from ALS. Since 2009, a prospective registry records ...all incident cases of ALS in Emilia Romagna Region, Italy (4.4 million inhabitants) referred to its 17 neurological departments. For each patient, demographic and clinical information is collected by the physician in charge, including compilation of the ALSFRS-R at each clinical follow-up. Results showed that a confirmatory factor analysis on the three-factor model previously found (bulbar, motor, respiratory function) showed a good fit. Rasch analysis on the whole scale showed the need to collapse some rating categories, confirmed the multidimensionality of the ALSFRS-R, and demonstrated the presence of differential item functioning between patients with spinal versus bulbar onset. Moreover, some items included in the three ALSFRS-R subscales showed a problematic fit to the respective construct they were intended to measure. In conclusion, the interpretation of a total raw score of ALSFRS-R is hampered by ambiguities due to the different metric properties of the three domains the scale aggregates, and their content and structure. This study confirms that a refinement of ALSFRS-R is warranted, pointing to the need to revise its whole structure, and providing detailed guidelines for its revision.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Studies on the distribution of multiple sclerosis (MS) carried out in Southern Europe in the last years have shown a significant increase in the frequency of the disease. A previous descriptive ...survey in the Republic of San Marino, northern Italian peninsula, published in 1984 established that this area is at high risk for MS. We updated the frequency estimates of the disease by adopting a complete enumeration approach. On 31 December 2005, 50 MS patients (36 women and 14 men) yieldeda crude prevalence rate of 166.7 per 100 000 (95% CI 123.7—220), 235.3 (95% CI 165—327.4) for women and 95.2 (95% CI 52—160) for men. The average incidence from 1990 to 2005 was 7.9 (95% CI 5.3—11.1) per 100 000, 11.7 (95% CI 7.6—17.3) for women and 3.9 (95% CI 1.7—7.7) for men. We did not detect any significant temporal trend over the study period. These results confirm that in San Marino the disease occurs more frequently than that suggested in the past and support the data on MS frequency in continental Italy. The marked increase in MS prevalence ratio is partly due to the increasing survival of patients and the accumulation of new incidence cases owing to the reduction in diagnostic latency for better quality of neurological diagnostic procedures. However, an increased incidence of the disease could be considered. Multiple Sclerosis 2008; 14: 325—329. http://msj.sagepub.com
PDF
