Beam energy dependence of moments of the net-charge multiplicity distributions in Au+Au collisions at RHIC

We report the first measurements of the moments--mean (M), variance (σ(2)), skewness (S), and kurtosis (κ)--of the net-charge multiplicity distributions at midrapidity in Au+Au collisions at seven energies, ranging from sqrt[sNN]=7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, σ(2)/M, Sσ, and κσ(2), with the expectations from Poisson and negative binomial distributions (NBDs). The Sσ values deviate from the Poisson baseline and are close to the NBD baseline, while the κσ(2) values tend to lie between the two. Within the present uncertainties, our data do not show nonmonotonic behavior as a function of collision energy. These measurements provide a valuable tool to extract the freeze-out parameters in heavy-ion collisions by comparing with theoretical models.

Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC

We report measurements of single- and double-spin asymmetries for W^{±} and Z/γ^{*} boson production in longitudinally polarized p+p collisions at sqrt[s]=510  GeV by the STAR experiment at RHIC. The asymmetries for W^{±} were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the W mass. The results are compared to theoretical predictions, constrained by polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05<x<0.2.

Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy and tends to vanish by 7.7 GeV. This implies the dominance of hadronic interactions over partonic ones at lower collision energies.

Dielectron mass spectra from Au+Au collisions at √[s(NN)]=200 GeV

We report the STAR measurements of dielectron (e(+)e(-)) production at midrapidity (|y(ee)|<1) in Au+Au collisions at √[s(NN)]=200  GeV. The measurements are evaluated in different invariant mass regions with a focus on 0.30-0.76 (ρ-like), 0.76-0.80 (ω-like), and 0.98-1.05 (ϕ-like)   GeV/c(2). The spectrum in the ω-like and ϕ-like regions can be well described by the hadronic cocktail simulation. In the ρ-like region, however, the vacuum ρ spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of 1.77±0.11(stat)±0.24(syst)±0.33(cocktail) is determined with respect to the hadronic cocktail simulation that excludes the ρ meson. The excess yield in the ρ-like region increases with the number of collision participants faster than the ω and ϕ yields. Theoretical models with broadened ρ contributions through interactions with constituents in the hot QCD medium provide a consistent description of the dilepton mass spectra for the measurement presented here and the earlier data at the Super Proton Synchrotron energies.

Enhancing human islet transplantation by localized release of trophic factors from PLG scaffolds

Islet transplantation represents a potential cure for type 1 diabetes, yet the clinical approach of intrahepatic delivery is limited by the microenvironment. Microporous scaffolds enable extrahepatic transplantation, and the microenvironment can be designed to enhance islet engraftment and function. We investigated localized trophic factor delivery in a xenogeneic human islet to mouse model of islet transplantation. Double emulsion microspheres containing exendin-4 (Ex4) or insulin-like growth factor-1 (IGF-1) were incorporated into a layered scaffold design consisting of porous outer layers for islet transplantation and a center layer for sustained factor release. Protein encapsulation and release were dependent on both the polymer concentration and the identity of the protein. Proteins retained bioactivity upon release from scaffolds in vitro. A minimal human islet mass transplanted on Ex4-releasing scaffolds demonstrated significant improvement and prolongation of graft function relative to blank scaffolds carrying no protein, and the release profile significantly impacted the duration over which the graft functioned. Ex4-releasing scaffolds enabled better glycemic control in animals subjected to an intraperitoneal glucose tolerance test. Scaffolds releasing IGF-1 lowered blood glucose levels, yet the reduction was insufficient to achieve euglycemia. Ex4-delivering scaffolds provide an extrahepatic transplantation site for modulating the islet microenvironment to enhance islet function posttransplant.

Transient elastography in hepatitis B virus infection. Liver stiffness discrepancy due to sampling location

OBJECTIVE

To investigate the variability in liver stiffness (LS), measured by transient elastography, and determine the possible influencing factors in hepatitis B virus infection.

METHODS

This cross-sectional study was conducted at the Department of Infectious Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China from March to June 2010. Three successful measurements at different sites in 123 patients were obtained, and the LS discrepancy was calculated. The influence of clinical data on the discrepancy was also assessed.

RESULTS

The LS discrepancy was 1.3 (0.2-16.5) kPa and independently increased with a fibrosis stage: 0.9 (0.2-4.4) kPa in F0/F1, 1.5 (0.4-3.7) kPa in F2, 3.0 (0.3-9.4) kPa in F3, and 7.4 (3.1-16.5) kPa in F4. A discrepancy >/=2 kPa was observed in 45 (36.6%) patients: 8 (11.9%) with F0/F1, 7 (31.8%) with F2, 15 (73.7%) with F3, and 15 (100%) with F4. The incidence of discrepancy >/=2 kPa was only associated with fibrosis stage in multiple regression analysis. Discordance in fibrosis stages was observed in 33 (26.8%) patients, and was most frequent in stage F2 (F0/F1, 10.45%; F2, 68.2%; F3, 36.8%; and F4, 26.7%).

CONCLUSION

The LS discrepancy is common and associated with fibrosis stage independently. While determining the fibrosis stage and disease progression, LS discrepancy should be considered.

Valproate pretreatment protects pancreatic β-cells from palmitate-induced ER stress and apoptosis by inhibiting glycogen synthase kinase-3β

Background

Reduction of pancreatic β-cells mass, major secondary to increased β-cells apoptosis, is increasingly recognized as one of the main contributing factors to the pathogenesis of type 2 diabetes (T2D), and saturated free fatty acid palmitate has been shown to induce endoplasmic reticulum (ER) stress that may contribute to promoting β-cells apoptosis. Recent literature suggests that valproate, a diffusely prescribed drug in the treatment of epilepsy and bipolar disorder, can inhibit glycogen synthase kinase-3β (GSK-3β) activity and has cytoprotective effects in neuronal cells and HepG2 cells. Thus, we hypothesized that valproate may protect INS-1 β-cells from palmitate-induced apoptosis via inhibiting GSK-3β.

Results

Valproate pretreatment remarkable prevented palmitate-mediated cytotoxicity and apoptosis (lipotoxicity) as well as ER distension. Furthermore, palmitate triggered ER stress as evidenced by increased mRNA levels of C/EBP homologous protein (CHOP) and activating transcription factor 4 (ATF4) in a time-dependent fashion. However, valproate not only reduced the mRNA and protein expression of CHOP but also inhibited GSK-3β and caspase-3 activity induced by palmitate, whereas, the mRNA expression of ATF4 was not affected. Interestingly, TDZD-8, a specific GSK-3β inhibitor, also showed the similar effect on lipotoxicity and ER stress as valproate in INS-1 cells. Finally, compared with CHOP knockdown, valproate displayed better cytoprotection against palmitate.

Conclusions

Valproate may protect β-cells from palmitate-induced apoptosis and ER stress via GSK-3β inhibition, independent of ATF4/CHOP pathway. Besides, GSK-3β, rather than CHOP, may be a more promising therapeutic target for T2D.

Enhanced susceptibility-weighted angiography (ESWAN) of cerebral arteries and veins at 1.5 Tesla

OBJECTIVE

Enhanced susceptibility-weighted angiography (ESWAN) is a three-dimensional (3D) multi-echo gradient-echo sequence which consists of both magnitude and phase images. This study aims to demonstrate the feasibility of ESWAN for the depiction of both cerebral arteries and veins at 1.5 T by comparing with time-of-flight (TOF) MR angiography (MRA) and MR venography (MRV).

METHODS

13 healthy volunteers underwent both ESWAN and 3D-TOF-MRA examinations. Among them, nine volunteers underwent an additional two-dimensional-TOF-MRV examination. With regard to the ESWAN sequence, both maximum intensity projection (MIP) and minimum intensity projection (mIP) images were reconstructed and compared with MIP reconstructions of the TOF MRA and the TOF MRV.

RESULTS

Concerning the depiction of the constituent segments of the Circle of Willis, as well as A1, A2, A3 (segments of the anterior cerebral artery), M1, M2 (segments of the middle cerebral artery), P1 and P2 (segments of the posterior cerebral artery), the value of the ESWAN MIP was comparable to that of the TOF MRA without regard to visualization of branches, vessel homogeneity and wall irregularities or slight stenosis. ESWAN-mIP visualized more deep cerebral veins than TOF MRV in this study.

CONCLUSION

By use of either mIP reconstruction of a long echo data set or MIP reconstruction of a short echo data set, ESWAN allows simultaneous visualization of both cerebral veins and proximal segments of intracerebral arteries at 1.5 T.

ADVANCES IN KNOWLEDGE

ESWAN acquires multiple images at different echo times corresponding to different T2* weightings, wherein a short echo TOF-MRA data set and a long echo susceptibility-weighted imaging-MRV data set are obtained simultaneously.

A Reassessment of Virulence Phenotypes of Soybean Cyst Nematode (Heterodera glycines) in China with HG Typing Method

Soybean cyst nematode, Heterodera glycines Ichinohe, is the most destructive pest of soybean (Glycine max) worldwide, including China. H. glycines virulence phenotypes can be described in two ways. One is the race determination test that uses four soybean lines to categorize H. glycines into 16 "races" (3). The HG type designation is similar, but avoids the implications of the term "race" and includes seven soybean lines rather than four (2). In China, previous data revealed the occurrence of nine H. glycines races including races 1 through 7, 9, and 14, whereas HG types have not been recorded (1). The objective of this study was to reassess virulence phenotypes of H. glycines in China by means of HG types. In 2011 and 2012, 10 SCN populations from the primary soybean production regions of China were identified as six races (races 1, 2, 3, 4, 5, 6, and 14) with the race test scheme (3) and were cultured on a H. glycines-susceptible soybean cultivar. In 2013, seven indicator soybean lines (PI 548402, PI 88788, PI 90763, PI 437654, PI 209332, PI 89772, and PI 548316) plus the susceptible standard soybean "Lee74" were used to determine the HG types of these populations following standardized procedures (2) with some modification in a growth chamber set at 28°C under 16-h days. After 30 days, females were extracted from roots and collected, and a female index was calculated for each indicator line (2,3). The average number of females on Lee74 was more than 100 in all the tests. Eight HG types were identified in the populations tested: HG type 0 (race 3), HG type 7 (race 3 or 6), HG type 2.7 (race 1 or 5), HG type 5.7 (race 3), HG type 1.3.7 (race 14), HG type 2.5.7 (race 1), HG type 1.2.5.7 (race 2), and HG type 1.2.3.5.7 (race 4). To our knowledge, this is the first report of H. glycines HG types in China, which will contribute to development of management strategies implementing the use of resistant cultivars. This work was supported by the Special Fund for Agro-scientific Research in the Public Interest 200903040-03 and the China Agriculture Research System CARS-04. References: (1) W. G. Lu et al. Agr. Sci. China 5:615, 2006. (2) T. L. Niblack et al. J. Nematol. 34:279, 2002. (3) R. D. Riggs and D. P. Schmitt. J. Nematol. 20:392, 1988.

Beam-energy dependence of the directed flow of protons, antiprotons, and pions in Au+Au collisions

Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton dv1/dy|y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.

Submicron-scale surface architecture of tricalcium phosphate directs osteogenesis in vitro and in vivo

A current challenge of synthetic bone graft substitute design is to induce bone formation at a similar rate to its biological resorption, matching bone's intrinsic osteoinductivity and capacity for remodelling. We hypothesise that both osteoinduction and resorption can be achieved by altering surface microstructure of beta-tricalcium phosphate (TCP). To test this, two TCP ceramics are engineered with equivalent chemistry and macrostructure but with either submicron- or micron-scale surface architecture. In vitro, submicron-scale surface architecture differentiates larger, more active osteoclasts--a cell type shown to be important for both TCP resorption and osteogenesis--and enhances their secretion of osteogenic factors to induce osteoblast differentiation of human mesenchymal stem cells. In an intramuscular model, submicrostructured TCP forms 20 % bone in the free space, is resorbed by 24 %, and is densely populated by multinucleated osteoclast-like cells after 12 weeks; however, TCP with micron-scale surface architecture forms no bone, is essentially not resorbed, and contains scarce osteoclast-like cells. Thus, a novel submicron-structured TCP induces substantial bone formation and is resorbed at an equivalent rate, potentially through the control of osteoclast-like cells.

Downregulation of FAP suppresses cell proliferation and metastasis through PTEN/PI3K/AKT and Ras-ERK signaling in oral squamous cell carcinoma

It is largely recognized that fibroblast activation protein (FAP) is expressed in cancer-associated fibroblasts (CAFs) of many human carcinomas. Furthermore, FAP was recently also reported to be expressed in carcinoma cells of the breast, stomach, pancreatic ductal adenocarcinoma, colorectum, and uterine cervix. The carcinoma cell expression pattern of FAP has been described in several types of cancers, but the role of FAP in oral squamous cell carcinoma (OSCC) is unknown. The role of endogenous FAP in epithelium-derived tumors and molecular mechanisms has also not been reported. In this study, FAP was found to be expressed in carcinoma cells of OSCC and was upregulated in OSCC tissue samples compared with benign tissue samples using immunohistochemistry. In addition, its expression level was closely correlated with overall survival of patients with OSCC. Silencing FAP inhibited the growth and metastasis of OSCC cells in vitro and in vivo. Mechanistically, knockdown of FAP inactivated PTEN/PI3K/AKT and Ras-ERK and its downstream signaling regulating proliferation, migration, and invasion in OSCC cells, as the inhibitory effects of FAP on the proliferation and metastasis could be rescued by PTEN silencing. Our study suggests that FAP acts as an oncogene and may be a potential therapeutic target for patients with OSCC.

Jet-hadron correlations in √[s(NN)]=200 GeV p+p and central Au+Au collisions

Azimuthal angular correlations of charged hadrons with respect to the axis of a reconstructed (trigger) jet in Au+Au and p+p collisions at √[s(NN)]=200  GeV in STAR are presented. The trigger jet population in Au+Au collisions is biased toward jets that have not interacted with the medium, allowing easier matching of jet energies between Au+Au and p+p collisions while enhancing medium effects on the recoil jet. The associated hadron yield of the recoil jet is significantly suppressed at high transverse momentum (pTassoc) and enhanced at low pTassoc in 0%-20% central Au+Au collisions compared to p+p collisions, which is indicative of medium-induced parton energy loss in ultrarelativistic heavy-ion collisions.