Wγ production and limits on anomalous WWγ couplings in pp collisions at sqrt[s] = 1.96 TeV

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(→lν) + γ production in eγ and μγ final states. Using data corresponding to an integrated luminosity of 4.2  fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp → Wγ + X → lνγ + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WWγ couplings for data from hadron colliders: -0.4<Δκ(γ)<0.4 and -0.08<λ(γ)<0.07 at the 95% C.L.

The role of liver transplantation for intrahepatic cholangiocarcinoma: a single-center experience

BACKGROUND/AIM

Intrahepatic cholangiocarcinoma (ICC) is not a widely accepted indication for liver transplantation (LT). The present study describes our institutional experience with patients who underwent transplantation for ICC.

METHODS

A retrospective analysis was performed on 11 consecutive patients with ICC who underwent LT between October 2003 and November 2008 at our institution.

RESULTS

At a median patient follow-up interval of 10 months (2-56), the median survival time was 9 months (2.5-53). The perioperative mortality and the recurrence rate were 0 and 45.5%, respectively. Five patients are currently alive 10, 12, 41, 51 and 53 months after LT, respectively. One patient died 3 months after LT as a result of bile leak and toxic shock, and 5 patients died of tumor recurrences at 2.5, 8, 8, 9 and 10 months post-LT, respectively. The 1-, 2-, 3- and 4-year disease-free survival rates and overall survival rates of all the patients were 51.9, 51.9, 51.9 and 51.9%, and 50.5, 50.5, 50.5 and 50.5%, respectively.

CONCLUSION

With better and strict patient selection, the prognosis of LT for ICC could be improved. ICC patients with lymph node involvement, vascular or bile duct invasion are contraindicated for LT.

Search for a fermiophobic and standard model Higgs boson in diphoton final states

We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2  fb(-1) of pp collisions at sqrt[s]=1.96  TeV collected with the D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L.

Search for neutral minimal supersymmetric standard model Higgs bosons decaying to tau pairs produced in association with b quarks in pp collisions at √s = 1.96 TeV

We report results from a search for neutral Higgs bosons produced in association with b quarks using data recorded by the D0 experiment at the Fermilab Tevatron Collider and corresponding to an integrated luminosity of 7.3 fb(-1). This production mode can be enhanced in several extensions of the standard model (SM) such as in its minimal supersymmetric extension (MSSM) at high tanβ. We search for Higgs bosons decaying to tau pairs with one tau decaying to a muon and neutrinos and the other to hadrons. The data are found to be consistent with SM expectations, and we set upper limits on the cross section times branching ratio in the Higgs boson mass range from 90 to 320 GeV/c(2). We interpret our result in the MSSM parameter space, excluding tanβ values down to 25 for Higgs boson masses below 170 GeV/c(2).

Precision measurement of the ratio B(t→Wb)/B(t→Wq) and extraction of V(tb)

We present a measurement of the ratio of top quark branching fractions R=B(t→Wb)/B(t→Wq), where q can be a d, s, or b quark, in the lepton+jets and dilepton tt final states. The measurement uses data from 5.4 fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure R=0.90±0.04, and we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V(tb)| as |V(tb)|=0.95±0.02, assuming unitarity of the 3×3 CKM matrix.

Effects of dynamical grouping on cooperation in N-person evolutionary snowdrift game

A population typically consists of agents that continually distribute themselves into different groups at different times. This dynamic grouping has recently been shown to be essential in explaining many features observed in human activities including social, economic, and military activities. We study the effects of dynamic grouping on the level of cooperation in a modified evolutionary N-person snowdrift game. Due to the formation of dynamical groups, the competition takes place in groups of different sizes at different times and players of different strategies are mixed by the grouping dynamics. It is found that the level of cooperation is greatly enhanced by the dynamic grouping of agents, when compared with a static population of the same size. As a parameter β, which characterizes the relative importance of the reward and cost, increases, the fraction of cooperative players f(C) increases and it is possible to achieve a fully cooperative state. Analytically, we present a dynamical equation that incorporates the effects of the competing game and group size distribution. The distribution of cooperators in different groups is assumed to be a binomial distribution, which is confirmed by simulations. Results from the analytic equation are in good agreement with numerical results from simulations. We also present detailed simulation results of f(C) over the parameter space spanned by the probabilities of group coalescence ν(m) and group fragmentation ν(p) in the grouping dynamics. A high ν(m) and low ν(p) promotes cooperation, and a favorable reward characterized by a high β would lead to a fully cooperative state.

Development of a novel monoclonal antibody to B7-H4: characterization and biological activity

Objective

B7-H4, a member of the B7 family of immunoregulatory receptors, may participate in the negative regulation of cell-mediated immunity. Aberrant B7-H4 expression is detected in some tumors and it plays a role in the occurrence and development of tumors. The aim of this study was to elucidate the functional and structural properties of B7-H4.

Methods

We developed a monoclonal antibody (mAb) against the extracellular domain of B7-H4 through immunization of Balb/c mice with 3T3-mB7-H4 cells which expressed extrinsic B7-H4. A stable hybridoma cell line was established. Then, we analysised the characterization of the mAb through Enzyme linked immunosorbent assay (ELISA), Immunoprecipitation (IP), western blotting, Immunohistochemical (IHC), and tested the biological activity of the mAb.

Results

ELISA, IP, and western blotting analyses indicated that the mAb specifically recognized B7-H4. In addition, flow cytometry demonstrated that the mAb exhibits excellent reactivity when applied to leukemic cells. IHC staining revealed that the mAb stained in a predominantly diffuse plasmalemmal or cytoplasmic pattern when applied to certain tumor tissues. The preliminary results of the mAb's biological activity showed that the mAb could effectively inhibit the function of B7-H4 in the inhibition of T cell, while promotingg the growth of T cells and the secretion of Interleukin-2 (lL-2), Interleukin-4 (IL-4), Interleukin10 (IL-10) and Interferon-γ (IFN-γ).

Conclusion

This mAb will be a valuable tool for the further investigation of B7-H4 function.

Search for a fourth generation t' Quark in p ̄p collisions at √s = 1.96 TeV

We present a search for pair production of a fourth generation t' quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb(-1) of proton-antiproton collisions at √s = 1.96  TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the t' ̄t' production cross section that exclude at the 95% C.L. a t' quark that decays exclusively to W+jet with a mass below 285 GeV. We observe a small excess in the μ+jets channel which reduces the mass range excluded compared to the expected limit of 320 GeV in the absence of a signal.

Precise measurement of the top quark mass in the dilepton channel at D0

We measure the top quark mass (m(t)) in p ̄p collisions at a center of mass energy √s = 1.96 TeV using dilepton t ̄t→W(+)bW(-) ̄b→ℓ(+)ν(ℓ)bℓ(-) ̄ν(ℓ) ̄b events, where ℓ denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider. We obtain m(t)=174.0±1.8(stat)±2.4(syst) GeV, which is in agreement with the current world average m(t)=173.3±1.1 GeV. This is currently the most precise measurement of m(t) in the dilepton channel.

Apoptotic gene expression by human periodontal ligament cells following cyclic stretch

BACKGROUND AND OBJECTIVE

Periodontal ligament cells play an important role in maintaining homeostasis of periodontal tissue upon mechanical force loading caused by mastication or orthodontic force. Previous studies revealed force-driven periodontal ligament cell death via apoptosis, but the force-sensing genes assigned to the apoptotic pathway have not been fully characterized. The present study aimed to identify force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells.

MATERIAL AND METHODS

Human periodontal ligament cells were exposed to 20% stretch strain for 6 or 24 h, and the differential expression of 84 genes implicated in the apoptotic pathway were quantified by real-time PCR array technology.

RESULTS

Ten and 11 genes showed upregulated expression after 6 and 24 h stretches, respectively, and there were two downregulated genes in response to both 6 and 24 h stretches. These genes included those encoding the tumor necrosis factor ligand family (TNFSF8), tumor necrosis factor receptor family (FAS, TNFRSF10B, TNFRSF11B, TNFRSF25 and CD27), the Bcl-2 family (BAG3, BAK1, BCL2L11 and BCLAF1), the caspase family (CASP5 and CASP7), the inhibitor of apoptosis proteins family (BIRC3, BIRC6 and NAIP), the caspase recruitment domain family (RIPK2 and PYCARD) and the death domain family (DAPK1), as well as an oncogene (BRAF).

CONCLUSION

This study identified several force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells and should facilitate future studies on force-driven apoptosis by providing putative target genes.

Measurement of spin correlation in tt production using a matrix element approach

We determine the fraction of tt events with spin correlation, assuming that the spin of the top quark is either correlated with the spin of the top antiquark as predicted by the standard model or is uncorrelated. For the first time we use a matrix-element-based approach to study tt spin correlation. We use tt → W+ b W- b → ℓ+ νbℓ- ν b final states produced in pp collisions at a center-of-mass energy sqrt(s)=1.96  TeV, where ℓ denotes an electron or a muon. The data correspond to an integrated luminosity of 5.4  fb(-1) and were collected with the D0 detector at the Fermilab Tevatron collider. The result agrees with the standard model prediction. We exclude the hypothesis that the spins of the tt are uncorrelated at the 97.7% C.L.

Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site

Iodine occurs in multiple oxidation states in aquatic systems in the form of organic and inorganic species. This feature leads to complex biogeochemical cycling of stable iodine and its long-lived isotope, (129)I. In this study, we investigated the sorption, transport, and interconversion of iodine species by comparing their mobility in groundwaters at ambient concentrations of iodine species (10(-8) to 10(-7) M) to those at artificially elevated concentrations (78.7 μM), which often are used in laboratory analyses. Results demonstrate that the mobility of iodine species greatly depends on, in addition to the type of species, the iodine concentration used, presumably limited by the number of surface organic carbon binding sites to form covalent bonds. At ambient concentrations, iodide and iodate were significantly retarded (K(d) values as high as 49 mL g(-1)), whereas at concentrations of 78.7 μM, iodide traveled along with the water without retardation. Appreciable amounts of iodide during transport were retained in soils due to iodination of organic carbon, specifically retained by aromatic carbon. At high input concentration of iodate (78.7 μM), iodate was found to be reduced to iodide and subsequently followed the transport behavior of iodide. These experiments underscore the importance of studying iodine geochemistry at ambient concentrations and demonstrate the dynamic nature of their speciation during transport conditions.

Search for Resonant WW and WZ Production in pp collisions at √s=1.96 TeV

We search for resonant WW or WZ production by using up to 5.4 fb(-1) of integrated luminosity collected by the D0 experiment in run II of the Fermilab Tevatron Collider. The data are consistent with the standard model background expectation, and we set limits on a resonance mass by using the sequential standard model W' boson and the Randall-Sundrum model graviton G as benchmarks. We exclude a sequential standard model W' boson in the mass range 180-690 GeV and a Randall-Sundrum graviton in the range 300-754 GeV at 95% C.L.

Bounds on an anomalous dijet resonance in W+jets production in pp collisions at √s = 1.96 TeV

We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W boson in data corresponding to an integrated luminosity of 4.3 fb(-1) collected with the D0 detector at √s = 1.96 TeV. We find no evidence for anomalous resonant dijet production and derive upper limits on the production cross section of an anomalous dijet resonance recently reported by the CDF Collaboration, investigating the range of dijet invariant mass from 110 to 170 GeV/c(2). The probability of the D0 data being consistent with the presence of a dijet resonance with 4 pb production cross section at 145 GeV/c(2) is 8×10(-6).

Diagnostic accuracy of features predicting lower gastrointestinal malignancy: a colonoscopy database review of 10,603 Chinese patients

AIM

The diagnostic accuracy of colonoscopic features in predicting colorectal cancer (CRC) malignancy was studied.

METHOD

Consecutive patients who underwent first-time colonoscopy for lower gastrointestinal (GI) symptoms from 1998 to 2009 were identified. Gender, age, symptoms, endoscopic and pathologic findings were reviewed.

RESULTS

There were 10,603 patients. The overall prevalence of malignancy was 3.0% (313). Among these, only 58% (181/313) had features indicative of tumour formation. The overall sensitivity and specificity was 9.6% and 94.1%, respectively. The overall positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 2.66, 0.96 and 2.77, respectively.

CONCLUSION

A large proportion of Chinese patients with CRC presented without features indicative of tumour formation.