A study of the dimensional stability of the AMS silicon tracker Burger, W.J.; Perrin, E.; Alcaraz, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2003, Letnik:
512, Številka:
3
Journal Article
Recenzirano
The Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) for an operational period of 3 years. The AMS is the first cosmic ...ray spectrometer equipped with a large area silicon tracker
(>5
m
2)
. A preliminary version of the detector was flown on the NASA space shuttle
Discovery during June 2–12, 1998. Results for the dimensional stability of the silicon tracker planes based on the flight data, and the metrology data recorded before and after the flight, are presented.
Aging tests of full-scale CMS muon cathode strip chambers Acosta, D.; Apollinari, G.; Arisaka, K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2003, Letnik:
515, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Two CMS production Cathode Strip Chambers were tested for aging effects in a high-radiation environment at the Gamma Irradiation Facility at CERN. The chambers were irradiated over a large area: in ...total, about 2.1
m
2 or 700
m of wire in each chamber. The 40% Ar+50% CO
2+10% CF
4 gas mixture was provided by an open-loop gas system for one of the chambers and by a closed-loop re-circulating gas system for the other. After an accumulation of 0.3–0.4
C/cm of a wire, equivalent to about 30–50 years of operation at peak LHC luminosity, no significant changes in gas gain, chamber efficiency and wire signal noise were observed for either of the two chambers. The only consistent signs of aging were a small increase in dark current from ∼2 to ∼10
nA per plane of 600 wires and a decrease of strip-to-strip resistance from 1000 to 10–100
GΩ. Disassembly of the chambers revealed deposits on the cathode planes, while the anode wires remained fairly clean.
Design features and test results of the CMS endcap muon chambers Acosta, D; Apollinari, G; Arisaka, K ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2002, Letnik:
494, Številka:
1
Journal Article
Recenzirano
Presented are the main design features and performance results of the Cathode Strip Chambers for the CMS Endcap Muon system. Although the strips are unusually wide (up to
16
mm
) for the ...cathode-to-anode wire distance of
5
mm
, the six-plane structure of these chambers yields a spatial resolution of about
80
μm
, essentially uniform and independent of the strip width. In addition, the net spatial resolution of about one-tenth of the strip width at the hardware trigger level
(300
ns)
is obtained using a simple network of comparators. Time resolution achieved at the trigger level is
∼4
ns
(rms) that allows unambiguous tagging of bunch crossings which occur every
25
ns
. Aging test results, including those obtained with a recirculating gas system, are discussed; only minor aging affects were observed. The aging studies were performed with large-scale chambers;
700
m
of wire were irradiated for a dose up to
0.4
C/
cm
of the total accumulated charge.
The status of the Silicon Microvertex Detector (SMD) and its installation into the LEP-L3 experiment are presented, highlighting novel features and sophisticated techniques. Preliminary results based ...on 1993 data are given and compared with Monte Carlo predictions, to understand the detector performances and its tracking capabilities.
X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb deformities, pain, poor mineralization ...of the teeth and disproportionate short stature in children as well as hyperparathyroidism, osteomalacia, enthesopathies, osteoarthritis and pseudofractures in adults. The characteristics and severity of XLH vary between patients. Because of its rarity, the diagnosis and specific treatment of XLH are frequently delayed, which has a detrimental effect on patient outcomes. In this Evidence-Based Guideline, we recommend that the diagnosis of XLH is based on signs of rickets and/or osteomalacia in association with hypophosphataemia and renal phosphate wasting in the absence of vitamin D or calcium deficiency. Whenever possible, the diagnosis should be confirmed by molecular genetic analysis or measurement of levels of fibroblast growth factor 23 (FGF23) before treatment. Owing to the multisystemic nature of the disease, patients should be seen regularly by multidisciplinary teams organized by a metabolic bone disease expert. In this article, we summarize the current evidence and provide recommendations on features of the disease, including new treatment modalities, to improve knowledge and provide guidance for diagnosis and multidisciplinary care.
The 1994 running experience with the L3 Silicon Microvertex Detector is described; in particular we report on the detector performances observed during the year (namely the DAQ and detection ...efficiency and the signal to noise ratio) and on the reduction of the noise affecting the detector.
This review deals with podocyte proteins that play a significant role in the structure and function of the glomerular filter. Genetic linkage studies has identified several genes involved in the ...development of nephrotic syndrome and contributed to the understanding of the pathophysiology of glomerular proteinuria and/or focal segmental glomerulosclerosis. Here, we describe already well-characterized genetic diseases due to mutations in nephrin, podocin, CD2AP, alpha-actinin-4, WT1, and laminin β2 chain, as well as more recently identified genetic abnormalities in TRPC6, phospholipase C epsilon, and the proteins encoded by the mitochondrial genome. In addition, the role of the proteins which have shown to be important for the structure and functions by gene knockout studies in mice, are also discussed. Furthermore, some rare syndromes with glomerular involvement, in which molecular defects have been recently identified, are briefly described. In summary, this review updates the current knowledge of genetic causes of congenital and childhood nephrotic syndrome and provides new insights into mechanisms of glomerular dysfunction.
Abstract Autosomal dominant polycystic kidney disease is caused by loss-of-function mutations in the PKD1 or PKD2 genes encoding respectively polycystin-1 and polycystin-2. Polycystin-2 stimulates ...the inositol trisphosphate (IP3 ) receptor (IP3 R), a Ca2+ -release channel in the endoplasmic reticulum (ER). The effect of ER-located polycystin-1 is less clear. Polycystin-1 has been reported both to stimulate and to inhibit the IP3 R. We now studied the effect of polycystin-1 and of polycystin-2 on the IP3 R activity under conditions where the cytosolic Ca2+ concentration was kept constant and the reuptake of released Ca2+ was prevented. We also studied the interdependence of the interaction of polycystin-1 and polycystin-2 with the IP3 R. The experiments were done in conditionally immortalized human proximal-tubule epithelial cells in which one or both polycystins were knocked down using lentiviral vectors containing miRNA-based short hairpins. The Ca2+ release was induced in plasma membrane-permeabilized cells by various IP3 concentrations at a fixed Ca2+ concentration under unidirectional45 Ca2+ -efflux conditions. We now report that knock down of polycystin-1 or of polycystin-2 inhibited the IP3 -induced Ca2+ release. The simultaneous presence of the two polycystins was required to fully amplify the IP3 -induced Ca2+ release, since the presence of polycystin-1 alone or of polycystin-2 alone did not result in an increased Ca2+ release. These novel findings indicate that ER-located polycystin-1 and polycystin-2 operate as a functional complex. They are compatible with the view that loss-of-function mutations in PKD1 and in PKD2 both cause autosomal dominant polycystic kidney disease.
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