Boron carbide composites with highly aligned graphene nanoplatelets: light-weight and efficient electromagnetic interference shielding materials at high temperatures

B₄C-based ceramic composites containing 0-2 vol% highly aligned graphene nanoplatelets (GNPs) are fabricated. The electromagnetic interference (EMI) shielding properties of the obtained composites are investigated at X-band (8.2-12.4 GHz) frequency range from room-temperature up to 800 °C. All composites exhibit outstanding EMI shielding properties with satisfactory frequency- and thermal-stability. The shielding effectiveness (SE) of GNP/B₄C composites increases monotonically with increasing GNP loading. Superior room-temperature SE close to 40 dB is achieved with only 2 vol% GNPs and high SE around 35 dB still persists at 800 °C. Considering their relatively low density, GNP/B₄C composites possess a high specific shielding effectiveness (SSE) of 16 dB cm³ g^-1 which is among the highest values in reported ceramic-based shielding composites. Especially, the GNP/B₄C composite with 2 vol% GNPs exhibits the highest SSE/t (SSE divided by thickness) values at temperatures above 200 °C for all reported shielding composites, indicating that GNP/B₄C composites belong to the most promising high-temperature shielding composites. The excellent shielding properties of GNP/B₄C composites arise mainly from the high electrical conductivity, high dielectric loss and the multiple reflections by the highly aligned and large-sized GNP layers.

[Correlation between fetal borderline ventriculomegaly and chromosomal abnormalities]

Objective: To assess the association between fetal borderline ventriculomegaly (VM) diagnosed by prenatal ultrasound and chromosomal abnormality. Methods: Sonographic manifestation and chromosome of 129 cases with borderline VM diagnosed by prenatal sonography were analyzed retrospectively. All subjects were divided into 3 groups, 80 cases (62.0%, 80/129) in isolated VM (IVM) group, 27 cases (20.9%, 27/129) of VM with no additional structural abnormality group (including ultrasonic soft marker, abnormal volume of amniotic fluid and fetal growth restriction) and 22 cases (17.1%, 22/129) of VM with structural abnormality. Furthermore, the IVM group was sub-grouped according to fetal sex, lesion position and degree of expansion. The results of chromosome detection in different sub-group were analyzed statistically. Results: (1) Overall situation: in 129 enrolled cases of borderline VM, 8 cases of chromosomal abnormality were detected by CMA and the positive detection rate was 6.2% (8/129) , of which 2 cases were abnormal karyotype and 6 cases were pathologic copy number variation (p-CNV) . (2) The results of fetal chromosomal abnormalities detected in 3 groups: there were no case of abnormal karyotype and 4 cases of p-CNV in IVM group, the detection rate of chromosome abnormalities was 5.0% (4/80) . One case of abnormal karyotype and 2 cases of p-CNV in VM with no additional structural abnormality group, the detection rate was 11.1% (3/27) . One case of abnormal karyotype and no case of p-CNV in VM with structural abnormality group, the detection rate was 4.5% (1/22) . There were no significant difference among 3 groups (all P>0.05) . Conclusions: The risk of chromosomal abnormaliy increases in fetus with borderline VM. When the fetal VM is found by ultrasound, it is necessary to perform comprehensive scanning and regular follow-up. Fetal chromosomes examination is recommended.

The relation of local order to material properties in relaxor ferroelectrics

Correlating electromechanical and dielectric properties with nanometre-scale order is the defining challenge for the development of piezoelectric oxides. Current lead (Pb)-based relaxor ferroelectrics can serve as model systems with which to unravel these correlations, but the nature of the local order and its relation to material properties remains controversial. Here we employ recent advances in diffuse scattering instrumentation to investigate crystals that span the phase diagram of PbMg_1/3Nb_2/3O₃-xPbTiO₃ (PMN-xPT) and identify four forms of local order. From the compositional dependence, we resolve the coupling of each form to the dielectric and electromechanical properties observed. We show that relaxor behaviour does not correlate simply with ferroic diffuse scattering; instead, it results from a competition between local antiferroelectric correlations, seeded by chemical short-range order, and local ferroic order. The ferroic diffuse scattering is strongest where piezoelectricity is maximal and displays previously unrecognized modulations caused by anion displacements. Our observations provide new guidelines for evaluating displacive models and hence the piezoelectric properties of environmentally friendly next-generation materials.

CA916798 affects growth and metastasis of androgen-dependent prostate cancer cells

OBJECTIVE

Abnormal activation of androgen receptor (AR) signaling pathway is a critical pathogenic mechanism and therapeutic target for prostate cancer (PCa). The CA916798 is a tumor-associated gene and may be regulated by the androgen-AR pathway. This study aims to investigate the function of CA916798 in the growth and metastasis of androgen-dependent PCa cells.

MATERIALS AND METHODS

CA916798 expression in PCa cell lines was investigated. LNCap cells were divided into 4 groups: LNCap, LNCap+ Dihydrotestosterone (DHT), LNCap+DHT+siCA916798, and LNCap+DHT+siRA group. CA916798 expressions in LNCap cells treated with siCA917698 or siAR were examined. The viability, apoptosis, migration, and invasion of PCa cells were examined. Dual luciferase and ChIP assays were used to examine the interaction between the AR and CA916798.

RESULTS

Endogenous CA916798 mRNA levels in PC3 cells were significantly higher than those in LNCap cells (p < 0.05). However, CA916798 was androgen-sensitive in LNCap cells, but not in PC-3 cells. Dual luciferase and ChIP assays showed that AR could specifically bind to the promoter regions of the CA916798. Knockdown of CA916798 (LNCap+DHT+siCA916798) and AR (LNCap+DHT+siAR) resulted in decreased cell viability, migration, and invasion, while it induced apoptosis and G1 cell cycle arrest in LNCap cells.

CONCLUSIONS

DHT could initiate the transcription of CA916798, which further mediates the androgen-AR signaling pathway-dependent cell growth and metastasis of the prostate cancer cell line LNCap.

Amplitude Analysis of the Decay B[over ¯]^{0}→K_{S}^{0}π^{+}π^{-} and First Observation of the CP Asymmetry in B[over ¯]^{0}→K^{*}(892)^{-}π^{+}

The time-integrated untagged Dalitz plot of the three-body hadronic charmless decay B[over ¯]^{0}→K_{S}^{0}π^{+}π^{-} is studied using a pp collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of 3.0  fb^{-1}. The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the B[over ¯]^{0}→K_{S}^{0}π^{+}π^{-} decay branching fraction and CP asymmetries of the flavor-specific amplitudes are measured. The CP asymmetry between the conjugate B[over ¯]^{0}→K^{*}(892)^{-}π^{+} and B^{0}→K^{*}(892)^{+}π^{-} decay rates is determined to be -0.308±0.062.

Studies of the resonance structure in D 0 → K ∓ π ± π ± π ∓ decays

Amplitude models are constructed to describe the resonance structure of D 0 → K - π + π + π - and D 0 → K + π - π - π + decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0  f b - 1 . The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes D 0 → a 1 ( 1260 ) + K - and D 0 → K 1 ( 1270 / 1400 ) + π - being prominent in D 0 → K - π + π + π - and D 0 → K + π - π - π + , respectively. Precise measurements of the lineshape parameters and couplings of the a 1 ( 1260 ) + , K 1 ( 1270 ) - and K ( 1460 ) - resonances are made, and a quasi model-independent study of the K ( 1460 ) - resonance is performed. The coherence factor of the decays is calculated from the amplitude models to be R K 3 π = 0.459 ± 0.010 ( stat ) ± 0.012 ( syst ) ± 0.020 ( model ) , which is consistent with direct measurements. These models will be useful in future measurements of the unitary-triangle angle γ and studies of charm mixing and C P violation.

Evidence for the Rare Decay Σ^{+}→pμ^{+}μ^{-}

A search for the rare decay Σ^{+}→pμ^{+}μ^{-} is performed using pp collision data recorded by the LHCb experiment at center-of-mass energies sqrt[s]=7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant structure is observed in the dimuon invariant mass distribution, in contrast with a previous result from the HyperCP experiment. The measured Σ^{+}→pμ^{+}μ^{-} branching fraction is (2.2_{-1.3}^{+1.8})×10^{-8}, where statistical and systematic uncertainties are included, which is consistent with the standard model prediction.

Measurement of the Ratio of the B^{0}→D^{*-}τ^{+}ν_{τ} and B^{0}→D^{*-}μ^{+}ν_{μ} Branching Fractions Using Three-Prong τ-Lepton Decays

The ratio of branching fractions R(D^{*-})≡B(B^{0}→D^{*-}τ^{+}ν_{τ})/B(B^{0}→D^{*-}μ^{+}ν_{μ}) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. For the first time, R(D^{*-}) is determined using the τ-lepton decays with three charged pions in the final state. The B^{0}→D^{*-}τ^{+}ν_{τ} yield is normalized to that of the B^{0}→D^{*-}π^{+}π^{-}π^{+} mode, providing a measurement of B(B^{0}→D^{*-}τ^{+}ν_{τ})/B(B^{0}→D^{*-}π^{+}π^{-}π^{+})=1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. The value of B(B^{0}→D^{*-}τ^{+}ν_{τ})=(1.42±0.094±0.129±0.054)% is obtained, where the third uncertainty is due to the limited knowledge of the branching fraction of the normalization mode. Using the well-measured branching fraction of the B^{0}→D^{*-}μ^{+}ν_{μ} decay, a value of R(D^{*-})=0.291±0.019±0.026±0.013 is established, where the third uncertainty is due to the limited knowledge of the branching fractions of the normalization and B^{0}→D^{*-}μ^{+}ν_{μ} modes. This measurement is in agreement with the standard model prediction and with previous results.

Depth dependant element analysis of PbMg1/3Nb2/3O3 using muonic x-rays

The relaxor PbMg_1/3Nb_2/3O₃ (PMN) has received attention due to its potential applications as a piezoelectric when doped with PbTiO₃ (PT). Previous results have found that there are two phases existing in the system, one linked to the near-surface regions of the sample, the other in the bulk. However, the exact origin of these two phases is unclear. In this paper, depth dependant analysis results from negative muon implantation experiments are presented. It is shown that the Pb content is constant throughout all depths probed in the sample, but the Mg and Nb content changes in the near-surface region below 100 μm. At an implantation depth of 60 μm, it is found that there is a 25% increase in Mg content, with a simultaneous 5% decrease in Nb content in order to maintain charge neutrality. These results show that the previously observed skin effects in PMN are due to a change in concentration and unit cell.

Measurement of the Ratio of Branching Fractions B(B_{c}^{+}→J/ψτ^{+}ν_{τ})/B(B_{c}^{+}→J/ψμ^{+}ν_{μ})

A measurement is reported of the ratio of branching fractions R(J/ψ)=B(B_{c}^{+}→J/ψτ^{+}ν_{τ})/B(B_{c}^{+}→J/ψμ^{+}ν_{μ}), where the τ^{+} lepton is identified in the decay mode τ^{+}→μ^{+}ν_{μ}ν[over ¯]_{τ}. This analysis uses a sample of proton-proton collision data corresponding to 3.0  fb^{-1} of integrated luminosity recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. A signal is found for the decay B_{c}^{+}→J/ψτ^{+}ν_{τ} at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/ψ)=0.71±0.17(stat)±0.18(syst). This result lies within 2 standard deviations above the range of central values currently predicted by the standard model.

Detection of hand-foot-mouth disease and its spatial-temporal Epidemiological characteristics with GIS platform

The aim of this study is to investigate the main category of hand-foot-mouth (HFM) virus and analyze the distribution characteristics and susceptible population of HFM disease in China. Infants who have had HFM disease for less than 7 days were selected from the First Affiliated Hospital of Guangxi Medical University, Guangxi, China. Various specimens were collected from the infants, and EV71 and CA16 nucleic acid detections were performed using fluorescence quantitative assay. The positive results of the specimens were compared to determine the components of the pathogen. Moreover, the data of the target cases were analyzed based on Geographic Information System (GIS) to obtain the spatial-temporal epidemiological features of HFM disease in China. The detection rate of HFM virus in the throat swab, feces, bleb fluid and cerebrospinal fluid were 75%, 81.13%, 85.71% and 25%, respectively, indicating that the detection rate of virus in the bleb fluid was the highest. When the detection was based on more than one specimen, it was found that the positive rate was higher compared to detection based on a single specimen. The positive detection rate of EV71 in the target specimens was significantly higher than that of CA16 and mixed infection. Moreover, CA16 infection was usually accompanied by EV71 infection. As to spatial-temporal distribution, hand-foot-month disease broke out in the South of China in April, then spread to the north, and diminished in July. There was a notable difference in the number of cases between different provinces. EV71 and CA16 are the main viruses inducing HFM disease, especially EV71. Fluorescence quantitative polymerase chain reaction with high sensitivity can be used to detect the copy number of viruses, which is applicable to the early diagnosis of HFM disease. The incidence of HFM disease is notably different according to the influence of time, geographical space, gender and the living conditions of the children. Early diagnosis and treatment based on scientific methods are needed to reduce the incidence of severe diseases and avoid death.

Search for Dark Photons Produced in 13 TeV pp Collisions

Searches are performed for both promptlike and long-lived dark photons, A^{'}, produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using A^{'}→μ^{+}μ^{-} decays and a data sample corresponding to an integrated luminosity of 1.6  fb^{-1} collected with the LHCb detector. The promptlike A^{'} search covers the mass range from near the dimuon threshold up to 70 GeV, while the long-lived A^{'} search is restricted to the low-mass region 214<m(A^{'})<350  MeV. No evidence for a signal is found, and 90% confidence level exclusion limits are placed on the γ-A^{'} kinetic-mixing strength. The constraints placed on promptlike dark photons are the most stringent to date for the mass range 10.6<m(A^{'})<70  GeV, and are comparable to the best existing limits for m(A^{'})<0.5  GeV. The search for long-lived dark photons is the first to achieve sensitivity using a displaced-vertex signature.

[The clinical characteristics, diagnosis and treatment of patients with gout in China]

Objective: To investigate the demographic characteristics, clinical features, diagnosis and treatment of patients with gout in China. Methods: Clinical data of 6 814 patients with gout from 100 hospitals in 27 provinces, municipalities or autonomous regions in China were collected and analyzed. Results: (1) The ratio of male to female in patients with gout was 14.7∶1. The mean age of onset was (48.8±15.1) years old. Mean serum urate level was (526.7±132.3) μmol/L. Patients' education background was of U-shaped distribution; (2) Hypertension was the most common comorbidity [15.8%(1 079/6 814)], then overweight or obesity [51.9%(3 536/6 814)]; (3) Alcohol and high-purine food intake were dominant triggering factors in men. The diagnosis of gout was made after onset in majority of patients with cardinal symptom arthralgia. Most patients had the disease less than 5 years, and the longer the course, the more flares in the previous year of entry; (4) Febuxostat was the mostly used urate-lowering medication. 20.7%(1 412/6 814), 10.8%(739/6 814) and 3.9%(265/6 814) of patients were followed up in 4 weeks, 12 weeks and 24 weeks after registration, and 18.9%(267/1 412), 29.1%(215/739) and 38.1%(101/265) of them reached the control target of serum urate levels, respectively. After treatment, patients' liver function was not affected, but serum creatinine levels decreased significantly. Conclusions: The proportion of gout patients who reach target serum urate level is very low. Further steps including education and survey need to be carried on.

Mechanism of hif-1α mediated hypoxia-induced permeability changes in bladder endothelial cells

This study aimed to investigate the mechanism of hypoxia-inducible factor-1 alpha (HIF-1α) mediated hypoxia-induced permeability changes in bladder endothelial cells. Models of in vitro hypoxic cell culture of bladder cancer, bladder cancer cells with low HIF-1α expression and HIF-1α RNA interference (RNAi) expression vector were established. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of HIF-1α and vascular endothelial growth factor (VEGF) in each group. Bladder cell permeability was determined. Results showed that protein and mRNA expression of HIF-1α and VEGF at 3 and 12 h of hypoxia were significantly higher than normal control (P<0.05), and peaked at 12 h. HIF-1α and VEGF expression in the hypoxic group and hypoxic+3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1) group were significantly higher than normal control (P<0.05), while expression in the hypoxic+YC-1 group was significantly lower than the hypoxic group (P<0.05). Bladder cell permeability in the hypoxic and hypoxic+YC-1 group were significantly increased compared to normal control (P<0.05), while in the hypoxic+YC-1 group was significantly decreased compared to the hypoxic group (P<0.05). Most of the cells in the stably transfected HIF-1α RNAi expression vector pcDNA6.2-GW/EmGFP-miR-siHIF-1α expressed green fluorescence protein (GFP) under fluorescence microscope. pcDNA6.2-GW/EmGFP-miR-siHIF-1α could significantly inhibit HIF-1α gene expression (P<0.05). HIF-1α and VEGF expression in the hypoxic group and siHIF-1α hypoxic group were significantly higher than normal group (P<0.05), while expression in the siHIF-1α hypoxic group was significantly lower than the hypoxic group (P<0.05). Findings suggest that HIF-1α is an important factor in the increase of bladder cancer cell permeability.