Measurement of high-pT single electrons from heavy-flavor decays in p + p collisions at square root of s = 200 GeV

The momentum distribution of electrons from decays of heavy flavor (charm and bottom) for midrapidity absolute value of y < 0.35 in p + p collisions at square root of s = 200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.3 < pT < 9 GeV/c. Two independent methods have been used to determine the heavy-flavor yields, and the results are in good agreement with each other. A fixed-order-plus-next-to-leading-log perturbative QCD calculation agrees with the data within the theoretical and experimental uncertainties, with the data/theory ratio of 1.71+/-0.02stat+/-0.18sys for 0.3 < pT < 9 GeV/c. The total charm production cross section at this energy has also been deduced to be sigma cc = 567+/-57stat+/-193sys microb.

Observation of B+ --> Lambda c+ Lambda c- K+ and B0 --> Lambda c+ Lambda c- K0 decays

We report the first measurements of the doubly charmed baryonic B decays B --> Lambda c+ Lambda c- K. The B+ --> Lambda c+ Lambda c- K+ decay is observed with a branching fraction of (6.5(-0.9)(+1.0)+/-1.1+/-3.4)x10(-4) and a statistical significance of 15.4sigma. The B0 --> Lambda c+ Lambda c- K0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/-1.2+/-4.1)x10(-4) and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda c+ --> pK- pi+ decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.

Aberrant methylation of the 8p22 tumor suppressor gene DLC1 in renal cell carcinoma

Epigenetic mechanisms involving DNA methylation and chromatin remodeling are important in silencing tumor suppressor genes (TSG) in various malignancies, including renal cell carcinoma (RCC). DLC1 (deleted in liver cancer 1)/ARHGAP7 is a recently identified 8p22 candidate TSG. Frequent methylation of the DLC1 promoter with resultant gene silencing has been reported in several tumors, but not in RCC yet. We examined DLC1 promoter methylation in 34 primary RCCs and the corresponding non-malignant tissues, and the correlation of DLC1 methylation with the clinicopathological characteristics of RCC patients. Although DLC1 methylation and downregulation were only detected in one of seven RCC cell lines using methylation-specific PCR (MSP) and semi-quantitative reverse-transcription PCR, we found that the DLC1 promoter was methylated in 35% (12/34) of primary RCC tumors, which was further confirmed by direct sequencing of MSP products and high-resolution bisulfite genomic sequencing. In contrast, only one of the 34 (3%) non-malignant renal tissues had weak methylation. Aberrant DLC1 methylation appeared to be a relatively early event during renal tumorigenesis since 33% of the RCC tumors with pT1 (TNM staging) showed methylation, which is similar to other late stage tumors. Thus, our results demonstrated that DLC1 methylation occurs in a subset of RCC tumors and may play a role in renal carcinogenesis.

Measurement of the quark mixing parameter cos2phi1 using time-dependent Dalitz analysis of B0 -->D[KS(0)pi + pi-]h0

We present a measurement of the angle phi1 of the Cabibbo-Kobayashi-Maskawa unitarity triangle using a time-dependent Dalitz analysis of D-->KS(0)pi + pi- decays produced in neutral B meson decay to a neutral D meson and a light meson (B0-->D*h0). The method allows a direct extraction of 2phi1 and, therefore, helps to resolve the ambiguity between 2phi1 and pi-2phi1 in the measurement of sin2phi1. We obtain sin2phi1= 0.78 +/- 0.44 +/- 0.22 and cos2varphi1 = 1.87(-0.53-0.32)(+0.40 + 0.22). The sign of cos2phi1 is determined to be positive at 98.3% C.L.

Evidence for B-->eta'pi and improved measurements for B-->eta'K

We report evidence for the exclusive two-body charmless hadronic B meson decay B-->eta'pi, and improved measurements of B-->eta'K. The results are obtained from a data sample of 386x10(6) BB pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We measure B(B+-->eta'pi+)=[1.76(-0.62)(+0.67)(stat)(-0.14)(+0.15)(syst)]x10(-6) and B(B0-->eta'pi0)=[2.79(-0.96)(+1.02)(stat)(-0.34)(+0.25)(syst)]x10(-6). We also find the ratio of B(B+-->eta'K+)/B(B0-->eta'K0)=1.17+/-0.08(stat)+/-0.03(syst) and measure the direct CP asymmetries for the charged modes.

Measurement of D0-->pilnu(Klnu) form factors and absolute branching fractions

Using a 282 fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider, we study D0 decays to K-l+nu and pi-l+nu final states. The D0 flavor and momentum are tagged through a full reconstruction of the recoiling charm meson and additional mesons from fragmentation. The reconstruction method provides very good resolution in neutrino momentum and in q2=(pl+pnu)2. Normalizing to the total number of D0 tags, we measure the absolute branching fractions to be B(D0-->Klnu)=(3.45+/-0.07stat+/-0.20syst)% and B(D0-->pilnu)=(0.255+/-0.019stat+/-0.016syst)% and the semileptonic form factors (within the modified pole model) f+K(0)=0.695+/-0.007stat+/-0.022syst and f+pi(0)=0.624+/-0.020stat+/-0.030syst.

Isotropic chest CT examination: diagnostic quality of reformats

AIM

To evaluate the image quality of axial and coronal reformats obtained from isotropic resolution 40-channel chest computed tomography (CT) examinations.

METHODS AND MATERIALS

Thirty consecutive patients with intravenous contrast-enhanced chest CT examinations using a 40-channel CT machine were enrolled for the study. The raw data were reconstructed into two sets of source axial images: 0.9 mm section width and 0.45 mm reconstruction interval (isotropic resolution) and 4mm section width with 3 mm reconstruction interval (anisotropic resolution; group A). The isotropic data set was reformatted into axial and coronal stacks (groups B and C, respectively) with 4 mm section width and 3 mm interval. Three independent readers evaluated stacks A to C using a three-point scale for resolution of right lower lobe segmental bronchi, edge sharpness of major and minor fissures, respiratory motion artefact, reconstruction artefact, noise and overall image quality.

RESULTS

The sharpness of fissures scored significantly higher with the coronal reformats (group C) compared with the axial image sets (groups A and B) (p<0.01). Noise in group A scored significantly lower than groups B or C (p<0.01). For other parameters there was no statistical difference between the groups. There was substantial or excellent agreement between the reviewers.

CONCLUSION

Isotropic imaging of the chest allows creation of reformats with similar image quality as similar thickness axial source images. These reformats are probably of sufficient quality to form the basis of clinical interpretation.

Measurement of forward-backward asymmetry and Wilson coefficients in B --> K*l+l-

We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients and in A9/A7 and A10/A7 in B --> K*l+l-, where l represents an electron or a muon. We find evidence for the forward-backward asymmetry with a significance of 3.4sigma. The results are obtained from a data sample containing 386 x 10(6) BB pairs that were collected on the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.

Measurement of azimuthal asymmetries in inclusive production of hadron pairs in e(+)e(-) annihilation at Belle

The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods, we find evidence of statistically significant azimuthal asymmetries for charged pion pairs in e(+)e(-) annihilation at a center-of-mass energy of 10.52 GeV, which can be attributed to a transverse polarization of the primordial quarks. The measurement was performed using a sample of 79 x 10(6) hadronic events collected with the Belle detector.

Observation of b-->dgamma and determination of /Vtd/Vts/

We report the observation of the flavor-changing neutral current process b-->dgamma using a sample of 386 x 106 B meson pairs accumulated by the Belle detector at the KEKB e+e- collider. We measure branching fractions for the exclusive modes B--->rho-gamma, B0rho0gamma, and B0omegagamma. Assuming that these three modes are related by isospin, we find B(B-->(rho,gamma)gamma)=[Formula: See Text] with a significance of 5.1sigma. This result is used to determine the ratio of Cabibbo-Kobayashi-Maskawa matrix elements /Vtd/Vts/ to be [Formula: See Text].

Measurement of the branching fraction, polarization, and asymmetry for decays, and determination of the Cabibbo-Kobayashi-Maskawa phase

We have measured the branching fraction , longitudinal polarization fraction f(L), and CP asymmetry coefficients A and S for B(0) --> rho(+) rho(-) decays with the Belle detector at the KEKB e(+) e(-) collider using 253 Fb(-1) of data. We obtain B = [22.8 +/- 3.8(stat)(+2.3)(-2.6)(syst)] x 10(-6), f(L) = 0.941 (+0.034)(-0.040)(stat) +/- 0.030(syst). A = 0.00 +/- 0.30(stat) +/- 0.09(syst) and S = 0.08 +/- 0.09(syst). These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase ; the solution consistent with the standard model is phi(2) = (88 +/- 17) degrees or 59 degrees < phi(2) < 115 degrees at 90% C.L.

Improved constraints on D0-D0 mixing in D0 --> K+ pi- decays from the Belle detector

We report the results of a search for D0-D0 mixing in D0 --> K+ pi- decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x and y, as well as for the parameter R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x'2,y') plane is obtained using a frequentist method. Assuming CP conservation, we find x'2 < 0.72 x 10(-3) and -9.9 x 10(-3) < y' < 6.8 x 10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R(D) = (0.377 +/- 0.008 +/- 0.005)%.

Observation of a chi(c2)' candidate in gamma gamma --> DD production at belle

We report on a search for new resonant states in the process gamma gamma --> DD. A candidate C-even charmonium state is observed in the vicinity of 3.93 GeV/c2. The production rate and the angular distribution in the gamma gamma center-of-mass frame suggest that this state is the previously unobserved chi(c2)', the 2(3)P2 charmonium state.

Functional epigenetics identifies a protocadherin PCDH10 as a candidate tumor suppressor for nasopharyngeal, esophageal and multiple other carcinomas with frequent methylation

Protocadherins constitute the largest subgroup in the cadherin superfamily of cell adhesion molecules. Their major functions are poorly understood, although some are implicated in nervous system development. As tumor-specific promoter methylation is a marker for tumor suppressor genes (TSG), we searched for epigenetically inactivated TSGs using methylation-subtraction combined with pharmacologic demethylation, and identified the PCDH10 CpG island as a methylated sequence in nasopharyngeal carcinoma (NPC). PCDH10 is broadly expressed in all normal adult and fetal tissues including the epithelia, though at different levels. It resides at 4q28.3--a region with hemizygous deletion detected by array-CGH in NPC cell lines; however, PCDH10 itself is not located within the deletion. In contrast, its transcriptional silencing and promoter methylation were frequently detected in multiple carcinoma cell lines in a biallelic way, including 12/12 nasopharyngeal, 13/16 esophageal, 3/4 breast, 5/5 colorectal, 3/4 cervical, 2/5 lung and 2/8 hepatocellular carcinoma cell lines, but not in any immortalized normal epithelial cell line. Aberrant methylation was further frequently detected in multiple primary carcinomas (82% in NPC, 42-51% for other carcinomas), but not normal tissues. The transcriptional silencing of PCDH10 could be reversed by pharmacologic demethylation with 5-aza-2'-deoxycytidine or genetic demethylation with double knockout of DNMT1 and DNMT3B, indicating a direct epigenetic mechanism. Ectopic expression of PCDH10 strongly suppressed tumor cell growth, migration, invasion and colony formation. Although the epigenetic and genetic disruptions of several classical cadherins as TSGs have been well documented in tumors, this is the first report that a widely expressed protocadherin can also function as a TSG that is frequently inactivated epigenetically in multiple carcinomas.

Measurements of B decays to two kaons

We report measurements of B meson decays to two kaons using 253 fb(-1) of data collected with the Belle detector at the KEKB energy-asymmetric e+ e- collider. We find evidence for signals in B+ --> K0 K+ and B0 --> K0 K0 with significances of 3.0sigma and 3.5sigma, respectively. (Charge-conjugate modes are included.) The corresponding branching fractions are measured to be [symbol: see text](B+ --> K0 K+) = (1.0 +/- 0.4 +/- 0.1) x 10(-6) and [symbol: see text](B0 --> K0 K0) = (0.8 +/- 0.3 +/- 0.1) x 10(-6). These decay modes are examples of hadronic bd transitions. No signal is observed in the decay B0 --> K+ K-, and we set an upper limit of 3.7 x 10(-7) at 90% confidence level.

Measurement of the wrong-sign decays D0 --> K+ pi- pi0 and D0 --> K+ pi- pi+ pi-, and search for CP violation

Using 281 fb-1 of data from the Belle experiment recorded at or near the (4S) resonance, we have measured the rates of the "wrong-sign" decays D0 --> K+ pi- pi0 and D0 --> K+ pi- pi+ pi- relative to those of the Cabibbo-favored decays D0 --> K- pi+ pi0 and D0 --> K- pi+ pi+ pi-. These wrong-sign decays proceed via a doubly Cabibbo-suppressed amplitude or via D0-D0 mixing; the latter has not yet been observed. We obtain R(WS)(K pi pi0) = [0.229 +/- 0.015(stat)(+0.013)(-0.009)(syst)]% and R(WS)(K3pi) = [0.320 +/- 0.018(stat)(+0.018)(0.013)(syst)]%. The CP asymmetries are measured to be -0.006 +/- 0.053 and -0.018 +/- 0.044 for the K+ pi- pi0 and K+ pi- pi+ pi- final states, respectively.

Measurements of the branching fraction and polarization in B+ --> rho+ K*0 decays

We present the results of a study of the charmless vector-vector decay B+ --> rho+ K*0, based on 253 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. We obtain the branching fraction B(B+ --> rho+ K*0) = [8.9 +/- 1.7(stat) +/- 1.2(syst)] x 10(-6). We also perform a helicity analysis of the rho and K* vector mesons, and obtain the longitudinal polarization fraction f(L)(B+ --> rho+ K*0) = 0.43 +/- 0.11(stat)(-0.02)(+0.05) (syst).

The Stress-Responsive Gene GADD45G Is a Functional Tumor Suppressor, with Its Response to Environmental Stresses Frequently Disrupted Epigenetically in Multiple Tumors

The CpG island of GADD45G was identified as a target sequence during the identification of hypermethylated genes using methylation-sensitive representational difference analysis combined with 5-aza-2'-deoxycytidine demethylation. Located at the commonly deleted region 9q22, GADD45G is a member of the DNA damage-inducible gene family. In response to stress shock, GADD45G inhibits cell growth and induces apoptosis. Same as other GADD45 members, GADD45G is ubiquitously expressed in all normal adult and fetal tissues. However, its transcriptional silencing or down-regulation and promoter hypermethylation were frequently detected in tumor cell lines, including 11 of 13 (85%) non-Hodgkin's lymphoma, 3 of 6 (50%) Hodgkin's lymphoma, 8 of 11 (73%) nasopharyngeal carcinoma, 2 of 4 (50%) cervical carcinoma, 5 of 17 (29%) esophageal carcinoma, and 2 of 5 (40%) lung carcinoma and other cell lines but not in any immortalized normal epithelial cell line, normal tissue, or peripheral blood mononuclear cells. The silencing of GADD45G could be reversed by 5-aza-2'-deoxycytidine or genetic double knockout of DNMT1 and DNMT3B, indicating a direct epigenetic mechanism. Aberrant methylation was further frequently detected in primary lymphomas although less frequently in primary carcinomas. Only one single sequence change in the coding region was detected in 1 of 25 cell lines examined, indicating that genetic inactivation of GADD45G is very rare. GADD45G could be induced by heat shock or UV irradiation in unmethylated cell lines; however, this stress response was abolished when its promoter becomes hypermethylated. Ectopic expression of GADD45G strongly suppressed tumor cell growth and colony formation in silenced cell lines. These results show that GADD45G can act as a functional new-age tumor suppressor but being frequently inactivated epigenetically in multiple tumors.

Observation of B+ --> plambdagamma

We report the first observation of the radiative hyperonic B decay B+ --> plambdagamma, using a 140 fb(-1) data sample recorded on upsilom(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured branching fraction is [symbol: see text](B+ --> plambdagamma) = (2.16(+0.58)(-0.53) +/- 0.20) x 10(-6). We examine its M(plambda) distribution and observe a peak near threshold. This feature is expected by the short-distance b --> sgamma transition. A search for B+ --> pepsilon0gamma yields no significant signal, and we set a 90% confidence-level upper limit on the branching fraction of [symbol: see textB+ --> pepsilon0gamma <4.6 x 10(-6).

Evidence for B0 --> D+ D- and observation of B- --> D0D- and B- -->D0D*- decays

We report evidence for B(0) --> D(0)D(-) and the first observation of the decay modes B(-) --> D(0)D(-) and B(-) --> D(0)D(*-) based on a sample of 152 x 10(6) BB events collected by the Belle detector at KEKB. The branching fractions for B(0) --> D(+) D(-), B--->D(0)D(-), and B--> D(0)D(*-) are found to be (1.91 +/- 0.51 +/- 0.30) x10(-4), (4.83 +/- 0.78 +/- 0.58) x 10(-4), and (4.57 +/- 0.71 +/- 0.56) x 10(-4), respectively. Charge asymmetries in the B---> D(0)D(-) and B(-) --> D(0)D(*-) channels are consistent with zero.