University of Siena

About: University of Siena is a education organization based out in Siena, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 12179 authors who have published 33334 publications receiving 1008287 citations. The organization is also known as: Università degli studi di Siena & Universita degli studi di Siena.

Measurement of the single-top-quark t-channel cross section in pp collisions at √s=7 TeV

Abstract: A measurement of the single-top-quark t-channel production cross section in pp collisions at s√=7 TeV with the CMS detector at the LHC is presented. Two different and complementary approaches have been followed. The first approach exploits the distributions of the pseudorapidity of the recoil jet and reconstructed top-quark mass using background estimates determined from control samples in data. The second approach is based on multivariate analysis techniques that probe the compatibility of the candidate events with the signal. Data have been collected for the muon and electron final states, corresponding to integrated luminosities of 1.17 and 1.56 fb^(−1), respectively. The single-top-quark production cross section in the t-channel is measured to be 67.2±6.1 pb, in agreement with the approximate next-to-next-to-leading-order standard model prediction. Using the standard model electroweak couplings, the CKM matrix element |V_(tb)| is measured to be 1.020 ± 0.046 (meas.) ± 0.017 (theor.).

Functional and Ultrastructural Features of DNA‐Fragmented Human Sperm

Abstract: The functional significance of deoxyribonucleic acid(DNA) fragmentation in ejaculated human sperm is unclear. In thisstudy the extent of DNA strand breakage in swim-up selectedsper-matozoa was evaluated by terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick end labeling (TUNEL)-coupledflow cytometry and correlated with several functional and morpho-logical sperm parameters. The extent of DNA fragmentation(mean 11.07% 8.00%, range 0.79%–42.64%, n 140) was pos-itively related to abnormal morphology and associated with defectsof the sperm tail. A negative correlation was found between DNAbreakage and progressive motility. When a stepwise multiple linearregression model was used to analyze the relationship betweenDNA fragmentation and the aforementioned parameters, only mo-tility results were included in the model. The presence of sper-matozoa showing submicroscopic characteristics resemblingthoseof somatic apoptosis has been reported in human ejaculate. Toverify whether sperm DNA fragmentation was associated with thepresence of such apoptotic-like cells, we performed electron mi-croscopy and TUNEL-coupled flow cytometry in a limited numberof sperm samples (n 24). Although we did not observe any sig-nificant relationship between DNA breakage and the characteris-tics that are suggestive of apoptosis, an association was foundwithseveral ultrastructural features, indicating an impaired motility.Hence, we conclude that in ejaculated sperm, DNA fragmentationdoes not correspond to the apoptosis-like phenomenon and that itis associated with defects of motility.Key words: Apoptosis, DNA fragmentation.J Androl 2000;21:903–912

Factors Correlated With Volleyball Spike Velocity

Abstract: BackgroundSpike effectiveness represents a determining element in volleyball To compete at a high level, the player must, in particular, produce a spike characterized by a high ball velocityHypothesisSome muscular and physical features could influence ball velocity during the volleyball spikeStudy DesignDescriptive laboratory studyMethodsA total of 19 male volleyball players from the 2 highest Belgian national divisions underwent an isokinetic assessment of the dominant shoulder and elbow Ball velocity performance (radar gun) during a spike test, morphological feature, and jump capacity (ergo jump) of the player were measured We tested the relationship between the isokinetic parameters or physical features and field performances represented by spike velocity We also compared first-division and second-division player dataResultsSpike velocity correlated significantly with strength performance of the dominant shoulder (internal rotators) and of the dominant elbow (flexors and extensors) in the conce

Clinical studies of fiber posts: a literature review.

Abstract: Purpose This literature review aimed to find answers to relevant questions regarding the clinical outcome of endontically treated teeth restored with fiber posts. Materials and methods All clinical studies published since 1990 in journals indexed in MEDLINE were retrieved by searching PubMed with the query terms "fiber posts and clinical studies." The reference list of the collected articles was also screened for further relevant citations. The strength of the evidence provided by the reviewed papers was assessed according to the criteria of evidence-based dentistry. Results Five randomized controlled trials (RCTs) on fiber posts have been published in peer-reviewed journals. A meta-analysis is not applicable to these studies since they do not address the same specific clinical question. Retrospective and prospective trials without controls are also available. Conclusions Two RCTs indicate that fiber-reinforced composite posts outperform metal posts in the restoration of endontically treated teeth. However, this evidence cannot be considered as conclusive. Longer-term RCTs would be desirable. The placement of a fiber-reinforced composite post protects against failure, especially under conditions of extensive coronal destruction. The most common type of failure with fiber-reinforced composite posts is debonding.