The Spatial Diffusion of Cherry Leaf Roll Virus Revealed by a Bayesian Phylodynamic Analysis.

Cherry leaf roll virus (CLRV) is an important plant pathogen that causes severe and detrimental effects on cherry and other fruit plants. Despite recent progress in plant pathology, molecular biology, and population genetics of CLRV, the spatiotemporal spread of this virus remains poorly studied. In this study, we employed a Bayesian phylodynamics framework to investigate the spatial diffusion patterns of CLRV by analyzing the coat protein gene sequences of 81 viral isolates collected from five different countries. Consistent with the trade of cherry, our Bayesian phylodynamic analyses pointed to viral origins in New Zealand and identified multiple migration pathways between Germany and other countries, suggesting that Germany has played an important role in CLRV transmission. The results of our study will be useful in developing sustainable management strategies to control this pathogen.

Anti-inflammation of isoliquiritigenin via the inhibition of NF-κB and MAPK in LPS-stimulated MAC-T cells.

BACKGROUND: The application of plant extracts has received great interest for the treatment of bovine mastitis. Isoliquiritigenin (ISL) is a rich dietary flavonoid that has significant antioxidative, anti-inflammatory and anticancer activities. This study was conducted to explore the protective efficacy and related mechanism of ISL against lipopolysaccharide (LPS)-stimulated oxidation and inflammation in bovine mammary epithelial cells (MAC-T) by in vitro experiments. RESULTS: Real-time PCR and ELISA assays indicated that ISL treatment at 2.5, 5 and 10 µg/mL significantly reduced the mRNA and protein expression of the oxidative indicators cyclooxygenase-2 and inducible nitric oxide synthase (P < 0.01), and of the inflammatory cytokines interleukin-6 (P < 0.05), interleukin-1ß (P < 0.01) and tumor necrosis factor-α (P < 0.01) in LPS-stimulated MAC-T cells. Moreover, Western blotting and immunofluorescence tests indicated that the phosphorylation levels of nuclear factor kappa (NF-κB) p65 and the inhibitor of NF-κB were significantly decreased by ISL treatment, thus blocking the nuclear transfer of NF-κB p65. In addition, ISL attenuated the phosphorylation levels of p38, extracellular signal-regulated kinase and c-jun NH2 terminal kinase. CONCLUSIONS: Our data demonstrated that ISL downregulated the LPS-induced inflammatory response in MAC-T cells. The anti-inflammatory and antioxidative activity of ISL involves the NF-κB and MAPK cascades.

Inhibitory effect of oil and fat on denitrification using food waste fermentation liquid as carbon source.

Food waste fermentation liquid (FWFL) can be used as carbon source to enhance nitrogen removal in wastewater treatment. However, the influence of lipid, a common component of food waste, on denitrification remains unclear. In this study, the effect of oil and fat on denitrification process and the underlying mechanisms were investigated using synthetic oil- and fat-bearing carbon source and verified with real FWFL. In the batch experiment, oil and fat had no obvious influence on denitrification, but in the semi-continuous experiment, the denitrification rate in the oil- and fat-added assays decreased to 44% and 38% of that in the control, respectively, after 45 batches. Oil and fat caused sludge floatation, and the floating sludge thickness increased with the continuous operation. Oil/fat-sludge aggregates were observed in the floating sludge and limited gas release. Microbial community analysis indicated that oil and fat did not affect denitrifying bacteria abundance. Limitation of mass transfer might be the main reason for the inhibition of oil and fat on denitrification. In the real FWFL experiment, the denitrification rate in the original and emulsified oil-bearing FWFL decreased to 24% and 56% of that in the demulsifying FWFL, respectively, after 45 batches. These findings indicate the necessity of removing lipids when FWFL is used as denitrification carbon source.

Enhanced thermoelectric properties of Bi0.5Sb1.5Te3 films by chemical vapor transport process.

Bi0.5Sb1.5Te3 films were prepared by a novel chemical vapor transport process through delicate controlling the temperature of the substrate and vapor source. The power factor reaches 30 µW cm⁻¹ K⁻¹ at room temperature, which is much higher than the value of the Bi0.5Sb1.5Te3 films prepared by other techniques. The enhancement of thermoelectric properties might be attributed to the higher carrier mobility (252 cm² V⁻¹ s⁻¹), coming from the effective interparticle contiguity of (00L) oriented nanoplates embedded in the present Bi0.5Sb1.5Te3 films.

Top-down fabrication of nano-scaled Bi2Se(0.3)Te(2.7) associated by electrochemical Li intercalation.

A convenient top-down method for preparation of Bi(2)Se(0.3)Te(2.7) crystalline nano-particles has been demonstrated. It contains two steps: (1) lithium was intercalated between the van der Waals bonded quintuple-layers by electrochemical process inside lithium ion batteries with precisely controlled speed and amount; (2) subsequent alcohol exposure of Li(x)Bi(2)Se(0.3)Te(2.7) to make the intercalated Li atoms explode like atom-scaled bombs and exfoliate the original micro/macro scaled materials into nano-scaled single crystalline particles with sizes around 10 nm. The intercalation process does not cost external energy, and can be scaled up by amplification of the intercalation devices.

Controllable synthesis and electrochemical hydrogen storage properties of Bi2Se3 architectural structures.

Two kinds of Bi2Se3 nanostructures, 3D rose-like hierarchitectures and monodisperse nanospheres, have been synthesized through adjusting the supersaturation of the precursor solution. Noticeable hydrogen storage capacity, amounting to 185 mA h g-1, has been found for the 3D rose-like hierarchitectures, which arises from the special micro/nano-hierarchitectures with highly crystallized flake-substructures.

Enhanced thermoelectric performance of single-walled carbon nanotubes/polyaniline hybrid nanocomposites.

Hybrid nanocomposites containing carbon nanotubes (CNTs) and ordered polyaniline (PANI) have been prepared through an in situ polymerization reaction using a single-walled nanotube (SWNT) as template and aniline as reactant. TEM, SEM, XRD, and Raman analyses show that the polyaniline grew along the surface of CNTs forming an ordered chain structure during the SWNT-directed polymerization process. The SWNT/PANI nanocomposites show both higher electrical conductivity and Seebeck coefficient as compared to pure PANI, which could be attributed to the enhanced carrier mobility in the ordered chain structures of the PANI. The maximum electrical conductivity and Seebeck coefficient of composites reach 1.25 x 10(4) S m(-1) and 40 microV K(-1), respectively, and the maximum power factor is up to 2 x 10(-5) W m(-1) K(-2), more than 2 orders of magnitude higher than the pure polyaniline. This study suggests that constructing highly ordered chain structure is a novel and effective way for improving the thermoelectric properties of conducting polymers.

Ultrahigh field emission current density from nitrogen-implanted ZnO nanowires.

An ultrahigh field emission current density of 10.3 mA cm(-2) was obtained from nitrogen-implanted ZnO nanowires. The sample was characterized and clearly showed a nitrogen doping signal. Field emission properties of the ZnO nanowires were considerably improved after N-implantation with lower turn-on field and a much higher current density. Removal of an amorphous layer, the presence of nanoscale protuberances, and surface-related defects were found to be responsible for the significantly enhanced field emission. Our work is important for the possible applications of ZnO nanowires in flat panel displays and high brightness electron sources.

Functionalizing nanowires with catalytic nanoparticles for gas sensing application.

Metal oxide semiconducting nanowires are among the most promising materials systems for use as conductometric gas sensors. These systems function by converting surface chemical processes, often catalytic processes, into observable conductance variations in the nanowire. The surface properties, and hence the sensing properties of these devices can be altered dramatically improving the sensitivity and selectivity, by the deposition of catalytic metal nanoparticles on the nanowire's surface. This leads not only to promising sensor strategies but to a route for understanding some of the fundamental science occurring on these nanoparticles and at the metal/nanowire junction. In particular studying these systems can lead to a better understanding of the influence of the catalyst particle on the electronic structure of the nanowire and its electron transport. This report surveys results obtained so far in this area. In particular, the comparative sensing performance of single quasi-1D chemiresistors (i.e., nanowires or nanobelts) before and after surface decoration with noble metal catalyst particles show significant improvement in sensitivity toward oxidizing and reducing gases. Moreover, one finds that the sensing mechanism can depend dramatically on the degree of metal coverage of the nanowire.

TEM investigation on the growth mechanism of carbon nanotubes synthesized by hot-filament chemical vapor deposition.

Carbon nanotubes (CNTs) were synthesized using hot-filament chemical vapor deposition on Ni film-coated Si substrate. The CNTs were well-aligned perpendicular to the substrate. The as-grown CNTs were bamboo-like in their morphology, and were investigated using SEM and high-resolution transmission electron microscopy (HRTEM). The SEM and HRTEM studies show that the both ends of a CNT contain metallic catalytic particles, which is different from results previously reported. Our analysis results provide strong evidence that the metallic catalyst remains in a liquid state during nanotube growth. The upward-growth pulling force of the CNT layer elongates the liquid nanoparticles, which are finally broken into two parts. One part remains at the substrate surface (base of the CNTs) and is responsible for the catalytic growth of the CNTs. The other part is enclosed at the tip of the CNTs and is inactive during CNT growth.