Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Obesity and immune function relationships.

The immunological processes involved in the collaborative defence of organisms are affected by nutritional status. Thus, a positive chronic imbalance between energy intake and expenditure leads to situations of obesity, which may influence unspecific and specific immune responses mediated by humoral and cell mediated mechanisms. Furthermore, several lines of evidence have supported a link between adipose tissue and immunocompetent cells. This interaction is illustrated in obesity, where excess adiposity and impaired immune function have been described in both humans and genetically obese rodents. However, limited and often controversial information exist comparing immunity in obese and non-obese subjects as well as about the cellular and molecular mechanisms implicated. In general terms, clinical and epidemiological data support the evidence that the incidence and severity of specific types of infectious illnesses are higher in obese persons as compared to lean individuals together with the occurrence of poor antibody responses to antigens in overweight subjects. Leptin might play a key role in linking nutritional status with T-cell function. The complexities and heterogeneity of the host defences concerning the immune response in different nutritional circumstances affecting the energy balance require an integral study of the immunocompetent cells, their subsets and products as well as specific and unspecific inducer/regulator systems. In this context, more research is needed to clarify the clinical implications of the alterations induced by obesity on the immune function

Mechanical homeostasis regulating adipose tissue volume

<p>Abstract</p> <p>Background</p> <p>The total body adipose tissue volume is regulated by hormonal, nutritional, paracrine, neuronal and genetic control signals, as well as components of cell-cell or cell-matrix interactions. There are no known locally acting homeostatic mechanisms by which growing adipose tissue might adapt its volume.</p> <p>Presentation of the hypothesis</p> <p>Mechanosensitivity has been demonstrated by mesenchymal cells in tissue culture. Adipocyte differentiation has been shown to be inhibited by stretching in vitro, and a pathway for the response has been elucidated. In humans, intermittent stretching of skin for reconstructional purposes leads to thinning of adipose tissue and thickening of epidermis – findings matching those observed in vitro in response to mechanical stimuli. Furthermore, protracted suspension of one leg increases the intermuscular adipose tissue volume of the limb. These findings may indicate a local homeostatic adipose tissue volume-regulating mechanism based on movement-induced reduction of adipocyte differentiation. This function might, during evolution, have been of importance in confined spaces, where overgrowth of adipose tissue could lead to functional disturbance, as for instance in the turtle. In humans, adipose tissue near muscle might in particular be affected, for instance intermuscularly, extraperitoneally and epicardially. Mechanical homeostasis might also contribute to protracted maintainment of soft tissue shape in the face and neck region.</p> <p>Testing of the hypothesis</p> <p>Assessment of messenger RNA-expression of human adipocytes following activity in adjacent muscle is planned, and study of biochemical and volumetric adipose tissue changes in man are proposed.</p> <p>Implications of the hypothesis</p> <p>The interpretation of metabolic disturbances by means of adipose tissue might be influenced. Possible applications in the head and neck were discussed.</p

Identification and Filtering of Uncharacteristic Noise in the CMS Hadron Calorimeter

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Comparison of direct machine parameter optimization versus fluence optimization with sequential sequencing in IMRT of hypopharyngeal carcinoma

Background: To evaluate the effects of direct machine parameter optimization in the treatment planning of intensity-modulated radiation therapy (IMRT) for hypopharyngeal cancer as compared to subsequent leaf sequencing in Oncentra Masterplan v1.5. Methods: For 10 hypopharyngeal cancer patients IMRT plans were generated in Oncentra Masterplan v1.5 (Nucletron BV, Veenendal, the Netherlands) for a Siemens Primus linear accelerator. For optimization the dose volume objectives (DVO) for the planning target volume (PTV) were set to 53 Gy minimum dose and 59 Gy maximum dose, in order to reach a dose of 56 Gy to the average of the PTV. For the parotids a median dose of 22 Gy was allowed and for the spinal cord a maximum dose of 35 Gy. The maximum DVO to the external contour of the patient was set to 59 Gy. The treatment plans were optimized with the direct machine parameter optimization ("Direct Step & Shoot", DSS, Raysearch Laboratories, Sweden) newly implemented in Masterplan v1.5 and the fluence modulation technique ("Intensity Modulation", IM) which was available in previous versions of Masterplan already. The two techniques were compared with regard to compliance to the DVO, plan quality, and number of monitor units (MU) required per fraction dose. Results: The plans optimized with the DSS technique met the DVO for the PTV significantly better than the plans optimized with IM (p = 0.007 for the min DVO and p 0.05). Plan quality, target coverage and dose homogeneity inside the PTV were superior for the plans optimized with DSS for similar dose to the spinal cord and lower dose to the normal tissue. The mean dose to the parotids was lower for the plans optimized with IM. Treatment plan efficiency was higher for the DSS plans with (901 +/- 160) MU compared to (1151 +/- 157) MU for IM (p-value < 0.05). Renormalization of the IM plans to the mean of the dose to 95% of the PTV (D(95)) of the DSS plans, resulted in similar target coverage and dose to the parotids for both strategies, at the cost of a significantly higher dose to the normal tissue and maximum dose to the target. The relative volume of the PTV receiving 107% or more of the prescription dose V(107) increased to 35.5% +/- 20.0% for the IM plan as compared to a mean of 0.9% +/- 0.9% for the DSS plan. Conclusion: The direct machine parameter optimization is a major improvement compared to the fluence modulation with subsequent leaf sequencing in Oncentra Masterplan v1.5. The resulting dose distribution complies better with the DVO and better plan quality is achieved for identical specification of DVO. An additional asset is the reduced number of MU as compared to IM

Performance of CMS hadron calorimeter timing and synchronization using test beam, cosmic ray, and LHC beam data

This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within ±2 ns

Intrinsic regulation of hemangioma involution by platelet-derived growth factor

Infantile hemangioma is a vascular tumor that exhibits a unique natural cycle of rapid growth followed by involution. Previously, we have shown that hemangiomas arise from CD133+ stem cells that differentiate into endothelial cells when implanted in immunodeficient mice. The same clonally expanded stem cells also produced adipocytes, thus recapitulating the involuting phase of hemangioma. In the present study, we have elucidated the intrinsic mechanisms of adipocyte differentiation using hemangioma-derived stem cells (hemSCs). We found that platelet-derived growth factor (PDGF) is elevated during the proliferating phase and may inhibit adipocyte differentiation. hemSCs expressed high levels of PDGF-B and showed sustained tyrosine phosphorylation of PDGF receptors under basal (unstimulated) conditions. Inhibition of PDGF receptor signaling caused enhanced adipogenesis in hemSCs. Furthermore, exposure of hemSCs to exogenous PDGF-BB reduced the fat content and the expression of adipocyte-specific transcription factors. We also show that these autogenous inhibitory effects are mediated by PDGF receptor-β signaling. In summary, this study identifies PDGF signaling as an intrinsic negative regulator of hemangioma involution and highlights the therapeutic potential of disrupting PDGF signaling for the treatment of hemangiomas

Genome-Wide Profiling of MicroRNAs in Adipose Mesenchymal Stem Cell Differentiation and Mouse Models of Obesity

In recent years, there has been accumulating evidence that microRNAs are key regulator molecules of gene expression. The cellular processes that are regulated by microRNAs include e.g. cell proliferation, programmed cell death and cell differentiation. Adipocyte differentiation is a highly regulated cellular process for which several important regulating factors have been discovered, but still not all are known to fully understand the underlying mechanisms. In the present study, we analyzed the expression of 597 microRNAs during the differentiation of mouse mesenchymal stem cells into terminally differentiated adipocytes by real-time RT-PCR. In total, 66 miRNAs were differentially expressed in mesenchymal stem cell-derived adipocytes compared to the undifferentiated progenitor cells. To further study the regulation of these 66 miRNAs in white adipose tissue in vivo and their dependence on PPARγ activity, mouse models of genetically or diet induced obesity as well as a mouse line expressing a dominant negative PPARγ mutant were employed