Effects of selenium and silicon on enhancing antioxidative capacity in ramie (Boehmeria nivea (L.) Gaud.) under cadmium stress

Hydroponic experiments were performed to investigate the ameliorating effects and mitigation mechanisms of selenium and silicon on Cd toxicity in Boehmeria nivea (L.) Gaud. Metal accumulation, chlorophyll content, activities of antioxidant enzymes, and antioxidant contents in ramie were evaluated. The results revealed that cadmium was mainly accumulated in the roots of plants rather than in the aerial parts. Additionally, under 5 mg L(-1) Cd stress, both Se (1 μmol L(-1)) and Si (1 mmol L(-1)) treatments decreased the Cd concentrations in plants. Besides, the treatments also inhibited the translocation ability of Cd from roots to the aboveground parts, which might be related to the decline of generation of reactive oxygen species (ROS). The application of Se and/or Si ameliorated Cd toxicity via stimulating the activities of antioxidant enzymes such as superoxide dismutase (SOD), guaiacol peroxidase (POD), and ascorbate peroxidase (APX), which resulted in the significant decrease of the contents of malondialdialdehyde (MDA) and hydrogen peroxide (H2O2) in ramie leaves. In addition, the content of nonenzymatic antioxidant such as glutathione (GSH) was increased significantly through the addition of selenite and silicate. Also, ascorbate (AsA) and vitamin E played a crucial role in scavenging excess ROS within plants. On the whole, appropriate doses of Se and Si were found to benefit plant growth and enhance the ability of ramie to alleviate Cd-induced stress. Moerover, the effects of combination of Se and Si appeared to be more superior compared to addition separately in response to Cd stress.

Characterization of Craniocervical Artery Dissection by Simultaneous MR Noncontrast Angiography and Intraplaque Hemorrhage Imaging at 3T

BACKGROUND AND PURPOSE

Craniocervical artery dissection is the most common cause of ischemic stroke identified in young adults. For the diagnosis of craniocervical artery dissection, multisequence MR imaging is recommended but is time-consuming. Recently, investigators proposed a simultaneous noncontrast angiography and intraplaque hemorrhage imaging technique allowing simultaneous noncontrast MRA and vessel wall imaging in a single scan. This study sought to investigate the feasibility of 3D simultaneous noncontrast angiography and intraplaque hemorrhage MR imaging in the characterization of craniocervical artery dissection.

MATERIALS AND METHODS

Twenty-four symptomatic patients (mean age, 45.0 ± 16.1 years; 21 men) with suspected craniocervical artery dissection were recruited. The 3D simultaneous noncontrast angiography and intraplaque hemorrhage 3D TOF MRA and black-blood imaging sequences were performed on a 3T MR imaging scanner. The agreement between simultaneous noncontrast angiography and intraplaque hemorrhage imaging and multisequence MR imaging in evaluating arterial dissection was determined.

RESULTS

Dissection was found to involve 1 artery in 22 patients and 2 arteries in 2 patients. The intramural hematoma and luminal occlusion were detected in 19 (79.2%) and 11 (45.8%) patients, respectively. In measuring stenosis, the Cohen κ value between 3D TOF MRA and simultaneous noncontrast angiography and intraplaque hemorrhage imaging was 0.82 (P < .001). All intramural hematomas on multisequence imaging were successfully identified by simultaneous noncontrast angiography and intraplaque hemorrhage imaging.

CONCLUSIONS

3D simultaneous noncontrast angiography and intraplaque hemorrhage imaging showed excellent agreement with multisequence MR imaging in evaluating luminal stenosis and intramural hematoma in patients with craniocervical artery dissection. The simultaneous noncontrast angiography and intraplaque hemorrhage imaging saved nearly 50% of scanning time compared with multisequence MR imaging. Our findings suggest that 3D simultaneous noncontrast angiography and intraplaque hemorrhage imaging might be an alternative, time-efficient diagnostic tool for craniocervical artery dissection.

Large-scale two-dimensional MoS₂ photodetectors by magnetron sputtering

We report on the demonstration of photodetectors based on large scale two-dimensional molybdenum disulfide (MoS2) transition metal dichalcogenides. Excellent film uniformity and precise control of the MoS2 thickness down to a monolayer (~0.75nm) were achieved by magnetron sputtering synthesis approach. In particular, the photodetectors integrated with five MoS2 monolayers exhibit a high photoresponsivity of 1.8 A/W, an external quantum efficiency exceeding 260%, and a photodetectivity of ~5 x 10(8) Jones for a wavelength of 850 nm, surpassing the performance of mechanically exfoliated based photodetectors.

Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.

Mutation of the rice ASL2 gene encoding plastid ribosomal protein L21 causes chloroplast developmental defects and seedling death

The plastid ribosome proteins (PRPs) play important roles in plastid protein biosynthesis, chloroplast differentiation and early chloroplast development. However, the specialised functions of individual protein components of the chloroplast ribosome in rice (Oryza sativa) remain unresolved. In this paper, we identified a novel rice PRP mutant named asl2 (Albino seedling lethality 2) exhibiting an albino, seedling death phenotype. In asl2 mutants, the alteration of leaf colour was associated with chlorophyll (Chl) content and abnormal chloroplast development. Through map-based cloning and complementation, the mutated ASL2 gene was isolated and found to encode the chloroplast 50S ribosome protein L21 (RPL21c), a component of the chloroplast ribosome large subunit, which was localised in chloroplasts. ASL2 was expressed at a higher level in the plumule and leaves, implying its tissue-specific expression. Additionally, the expression of ASL2 was regulated by light. The transcript levels of the majority of genes for Chl biosynthesis, photosynthesis and chloroplast development were strongly affected in asl2 mutants. Collectively, the absence of functional ASL2 caused chloroplast developmental defects and seedling death. This report establishes the important role of RPL21c in chloroplast development in rice.

Promoter hypomethylation and increased maspin expression in preeclamptic placentas in a Chinese population

OBJECTIVE

Preeclampsia is thought to begin with shallow trophoblast invasion and inadequate spiral artery remodeling. Maspin, a tumor-suppressor gene, plays a regulatory role in trophoblast invasion and motility. The tissue-specific methylation of the maspin promoter can regulate maspin gene expression in various cancers. We sought to detect maspin gene expression and assess the degrees of methylation of maspin promoter regions in preeclamptic placentas in the Han Chinese population and to investigate the potential role of maspin in the pathophysiology of preeclampsia.

METHODS

We conducted RT-PCR, immunohistochemistry and western blotting to characterize maspin gene expression and protein levels in the placentas from normal and preeclamptic pregnancies. Finally, using methylation-specific PCR and bisulfite sequencing PCR, we detected the degrees of methylation of the promoter regions of maspin in each of the two studied groups.

RESULTS

Maspin expression was increased at the mRNA and protein levels in the preeclamptic placentas compared to the control group. Maspin immunohistochemical staining revealed positive staining in the syncytio-cytotrophoblast layers and more diffuse staining in the preeclamptic group. The mean methylation level of the analyzed promoter region was significantly hypomethylated in the preeclamptic placentas compared to the control placentas, pointing to a negative relationship between maspin promoter methylation and gene expression.

DISCUSSION

Hypomethylation of the maspin promoter results in increased expression of maspin in preeclamptic placentas, which suggests a negative relationship between maspin methylation and maspin expression in this Han Chinese population. Thus, maspin is likely involved in the etiology of preeclampsia.

Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d + Au collisions at √sNN = 200 GeV

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6  GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200  GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.

Preparation of γ-Fe2O3/ZnFe2O4 nanoparticles by enhancement of surface modification with NaOH

BACKGROUND

During liquid-phase synthesis of γ-Fe2O3 nanoparticles by chemically induced transition in FeCl2 solution, enhancement of surface modification by adding ZnCl2 was attempted by using NaOH. By using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectrometry, and vibrating sample magnetometry, the dependence of the synthesis on the amount of additional NaOH was studied.

RESULTS

The experimental results show that the surface of the γ-Fe2O3 nanoparticles could be modified by adding ZnCl2 to form composite nanoparticles with γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn(OH)2 and adsorbed FeCl3, and that modification could be enhanced by adding NaOH.

CONCLUSIONS

In the experimental conditions, when the concentration of additional NaOH was below 0.70 M, the amounts of ZnFe2O4 and Zn(OH)2 phases increased slightly and that of adsorbed FeCl3 was unchanged. When the concentration of NaOH exceeded 0.70 M, the amount of FeCl3, ZnFe2O4, and Zn(OH)2 increased.

A polymorphism in melanoma differentiation-associated gene 5 may be a risk factor for enterovirus 71 infection

Enterovirus 71 (EV71) infection has a wide variety of clinical manifestations, from no symptoms to fatal disease. Host immune response may be a determinant of disease severity. We investigated the association of polymorphisms in three pattern recognition receptor (PRR) genes-toll-like receptor 3 (TLR3) (rs3775291), retinoic acid-inducible gene I (RIG-I) (rs10813831) and melanoma differentiation-associated gene 5 (MDA5) (rs1990760)-with the severity of EV71 infection. Polymorphisms of candidate genes in 87 EV71-infected patients and 57 asymptomatic controls were detected. Binary logistic regression analysis revealed statistically significant differences in polymorphism of MDA5 (rs1990760) between patients with severe EV71 infection and asymptomatic controls in an additive model (OR 0.424, 95% CI 0.213-0.845, p 0.015) and a dominant model (OR 0.256, 95% CI 0.103-0.635, p 0.003). Polymorphism of MDA5 (rs1990760) (OR 0.399, 95% CI 0.199-0.798, p 0.009) was found to be associated with the severity of EV71 infection with the analysis of ordinal logistic regression. These results indicated the association between MDA5 (rs1990760) polymorphism and an increased risk of a severe EV71 infection in Chinese children, which offers potential for investigating the innate immune mechanism of EV71 infection and identifying at-risk infants, for whom a preventive strategy may reduce the severity of EV71 infection.

Effects of common polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on susceptibility to colorectal cancer: a systematic review meta-analysis

PURPOSE

Emerging evidence has shown that single nucleotide polymorphisms occurred in microRNAs may contribute to the development of colorectal cancer (CRC). rs2910164 in miR-146a and rs11614913 in miR-196a2 are suggested to be associated with the susceptibility to CRC, but individually published studies revealed inconclusive results. To systematically summarize the possible correlationship between these polymorphisms and CRC risk, we performed this meta-analysis.

METHODS

We retrieved the relevant articles of the associations between these two microRNA polymorphisms and susceptibility to CRC for the period up to July 1, 2013. A total of seven articles were identified with 2,143 cases and 2,457 controls for miR-146a rs2910164, 1,594 cases and 2,252 controls for miR-196a2 rs11614913. Odds ratio and 95 % confidence interval were calculated to investigate the strength of the association.

RESULTS

The pooled analysis showed that miR-146a rs2910164 did not reveal any correlation with CRC susceptibility. However, a decreased risk was observed between miR-196a2 rs11614913 and CRC in all genetic models.

CONCLUSION

Our current meta-analysis demonstrates that miR-196a2 rs11614913 most likely contributes to decreased risk of CRC, whereas miR-146a rs2910164 may not be associated with the susceptibility to CRC.

Ang(1-7) treatment attenuates β-cell dysfunction by improving pancreatic microcirculation in a rat model of Type 2 diabetes

AIMS

Pancreatic microcirculation plays a pivotal role in the physiological function and survival of β-cells. Ang(1- 7) is a novel component of the renin angiotensin system (RAS) that has beneficial effects on microcirculation. In the present study, we investigated the effects of systemic Ang(1-7) administration (with or without its receptor Mas antagonist A- 779) on pancreatic microcirculation and β-cell function.

METHODS

These effects were studied in vivo using a rat model of Type 2 diabetes (T2DM). Pancreatic microcirculation and islet microvessel density were measured; and β-cell function, insulin content, and the apoptosis of islet cells were assessed, respectively. Additionally, we evaluated endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) concentration in islets.

RESULTS

After Ang(1-7) intervention, pancreatic microcirculation and intra-islet microvessel density were significantly improved (p<0.05), and more importantly, first-phase insulin secretion of β-cells as well as relative insulin content in islets were increased, and the amount of apoptotic islet cells was decreased (p<0.05). And eNOS expression and NO release were up-regulated in pancreatic islets by Ang(1-7) administration (p<0.05). These positive effects of Ang(1-7) were prevented by the addition of A-779 (p<0.05).

CONCLUSIONS

Our findings suggest that systemic Ang(1-7) treatment could attenuate β-cell dysfunction and ameliorate islet cell apoptosis in T2DM rats by improving pancreatic microcirculation, perhaps through the mechanism of endothelial vasodilation.

Strong field multiple ionization as a route to electron dynamics in a van der Waals cluster

We study the order in which a strong laser field removes multiple electrons from a van der Waals (vdW) cluster. The N2Ar, with an equilibrium T-shaped geometry, contains both a covalent and a vdW bond and serves as a simple yet rich example. Interestingly, the fragmenting double and triple ionizations of N2Ar with vdW bond breaking are favored when the vdW bond is aligned along the laser field polarization vector. However, the orientation of the covalent bond with respect to the laser field rules the triple ionization when both the covalent and vdW bonds are simultaneously broken. Electron-localization-assisted enhanced ionization and molecular orbital profile-dominated, orientation-dependent ionization are discussed to reveal the order of electrons release from different sites of N2Ar.