Biomedical subjects

C Ay

Publications and source records attributed to C Ay.

9 recordsLinked to original sources

PubMed2006

Low-density lipoprotein receptor-related protein 1 polymorphism 663 C > T affects clotting factor VIII activity and increases the risk of venous thromboembolism.

BACKGROUND: Clotting factor (F) VIII is an independent risk factor for primary and recurrent venous thromboembolism (VTE). The causes for high plasma FVIII levels are not fully understood, but an involvement of genetic factors has been demonstrated. A multifunctional endocytic receptor, low-density lipoprotein receptor-related protein 1 (LRP1), mediates cellular uptake and subsequent degradation of FVIII and may contribute to variations in FVIII levels. OBJECTIVE: We assessed the association of a genetic variation of LRP1 (663C > T) with basal FVIII levels and the risk of venous thrombosis in a group of high-risk patients and in healthy controls. PATIENTS AND METHODS: One hundred and fifty-two patients with a history of recurrent VTE (median age 56 years, 47% women) were compared with 198 age- and sex-matched controls (median age 53 years, 50% women). The LRP1 663C > T genotype was analyzed by mutagenic separated polymerase chain reaction assay and heterozygosity was confirmed by sequence analysis. RESULTS: LRP1 663C > T genotype distribution differed significantly between patients (663CC n = 138, 663CT n = 14) and controls (663CC n = 190, 663CT n = 8; P = 0.048). In multivariable linear regression analysis including LRP1 663C > T, ABO blood group, von Willebrand factor antigen, C-reactive protein and age, LRP1 663CT was independently associated with FVIII activity (P = 0.02). LRP1 663CT was also associated with increased odds for VTE following adjustment for blood group O, FV Leiden and the prothrombin variation 20210G > A in multivariate analysis (odds ratio 3.3, 95% CI 1.3-8.5). CONCLUSIONS: According to our data the LRP1 663C > T polymorphism influences plasma FVIII levels independently of blood group, C-reactive protein and von Willebrand factor and is significantly associated with the risk of VTE.

Case-Control Studies↗

PubMed2006

Search for pair production of scalar bottom quarks in pp collisions at square root of s = 1.96 TeV.

A search for direct production of scalar bottom quarks (b) is performed with 310 pb(-1) of data collected by the D0 experiment in pp collisions at square root s = 1.96 TeV at the Fermilab Tevatron Collider. The topology analyzed consists of two b jets and an imbalance in transverse momentum due to undetected neutralinos (chi(1)0), with chi(1)0 assumed to be the lightest supersymmetric particle. We find the data consistent with standard model expectations, and set a 95% C.L. exclusion domain in the (m(b), m(chi(1)0)) mass plane, improving significantly upon the results from run I of the Tevatron.

Journal Article↗

PubMed2006

Search for neutral, long-lived particles decaying into two muons in pp[over] collisions at sqrt[s]=1.96 TeV.

We present a search for a neutral particle, pair produced in pp[over] collisions at sqrt[s]=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses approximately 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events.

Journal Article↗

PubMed2006

Search for the standard model Higgs Boson in the pp[over]-->ZH-->nunu[over]bb[over] channel.

We report a search for the standard model (SM) Higgs boson based on data collected by the D0 experiment at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 260 pb(-1). We study events with missing transverse energy and two acoplanar b jets, which provide sensitivity to the ZH production cross section in the nunu[over]bb[over] channel, and to WH production when the lepton from the W-->lnu decay is undetected. The data are consistent with the SM background expectation, and we set 95% C.L. upper limits on sigma(pp[over]-->ZH/WH)xB(H-->bb[over]) from 3.4/8.3 to 2.5/6.3 pb, for Higgs-boson masses between 105 and 135 GeV.

Journal Article↗

PubMed2006

Search for associated higgs boson production WH-->WWW*-->l+/-nul'+/-nu'+X in pp collisions at square root s=1.96 Te V.

We present a search for associated Higgs boson production in the process pp-->WH-->WWW*-->l;+/-nul'+/-nu'+X in final states containing two like-sign isolated electrons or muons (e+/-e;+/-, e+/-micro+/-, or micro+/-micro+/-). The search is based on D0 run II data samples corresponding to integrated luminosities of 360-380 pb-1. No excess is observed over the predicted standard model background. We set 95% C.L. upper limits on sigma(pp-->WH)xBr(H-->WW*) between 3.2 and 2.8 pb for Higgs boson masses from 115 to 175 GeV.

Journal Article↗

PubMed2006

Search for neutral Higgs bosons decaying to tau pairs in pp[over ] collisions at sqrt[s]=1.96 TeV.

A search for the production of neutral Higgs bosons Phi decaying into tau(+)tau(-) final states in pp[over ] collisions at a center-of-mass energy of 1.96 TeV is presented. The data, corresponding to an integrated luminosity of approximately 325 pb(-1), were collected by the D0 experiment at the Fermilab Tevatron Collider. Since no excess compared to the expectation from standard model processes is found, limits on the production cross section times branching ratio are set. The results are combined with those obtained from the D0 search for Phib(b[over ])-->bb[over ]b(b[over ]) and are interpreted in the minimal supersymmetric standard model.

Journal Article↗

PubMed2006

Search for resonant second generation slepton production at the Fermilab Tevatron.

We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels mu-->chi(1)(0)mu, mu-->chi(2,3,4)(0)mu, and nu(mu)-->chi(1,2)(+/-)mu. We analyzed 0.38 fb(-1) of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter lambda(211)('), extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider.

Journal Article↗

PubMed2006

Direct limits on the oscillation frequency.

We report results of a study of the B(s)(0) oscillation frequency using a large sample of B(s)(0) semileptonic decays corresponding to approximately 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. The amplitude method gives a lower limit on the B(s)(0) oscillation frequency at 14.8 ps(-1) at the 95% C.L. At delta m(s) = 19 ps(-1), the amplitude deviates from the hypothesis A= 0(1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, delta m(s), gives a most probable value of 19 ps(-1) and a range of 17 < delta m(s) < 21 ps(-1)at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If delta m(s) lies above 22 ps(-1), then the probability that it would produce a likelihood minimum similar to the one observed in the interval 16-22 ps(-1) is (5.0 +/- 0.3)%.

Journal Article↗

PubMed1971

Bacteriology of dehydrated space foods.

The initial bacteriological requirement established in 1964 for space foods by the U.S. Army Natick Laboratories are: a total aerobic plate count (</= 10,000 per g), a total coliform count (</= 10 per g), fecal coliforms (negative per gram), fecal streptococci (</= 20 per g), coagulase-positive staphylococci (negative in 5 g) and salmonellae (negative in 10 g). Of the space foods and prototypes tested during 1968 and 1969, 93% complied with the total aerobic plate count, 98% had less than 1 coliform per g, and 99% were negative for fecal coliforms; 88% complied with the streptococci requirement; 100 and 98% were negative for staphylococci and salmonellae, respectively. Nineteen food samples which did not comply (as indicated parenthetically by actual counts per gram) with the requirements were (i) total aerobic plate count: beef soup and gravy base (18,000), chicken soup and gravy base (57,000), spaghetti with meat sauce (12,100 and 14,000), sugared coffee (> 300,000), chocolate ice cream cubes (20,000), and each of four samples of chocolate candy (12,000 to 61,000); (ii) coliforms: two out of three vanilla milk drinks (16 and 127) and one beef hash bar (14); (iii) fecal coliforms: one sample of chicken soup and gravy base positive; (iv) fecal streptococci: two samples of peanut cubes (40 and 108), coconut cubes (75), chicken soup and gravy base (2,650), beef soup and gravy base (33), and five out of six flavored milk drinks (23 to 300); (v) salmonellae: one each of chicken and beef soup and gravy base were positive.

Aerobiosis↗