Growth orientation mechanism of TiO2 nanotubes fabricated by anodization.

TiO2 nanotubes (TNTs) fabricated by anodization have been extensively researched in recent years. However, the mechanism that controls the growth orientation of anodic TNTs is still not clear. Here, we firstly examine their growth orientation systematically. Combined with the previous literature, the results of anodization on rotated Ti foil and thin Ti wire confirm that almost all of the TNTs grow vertically to the local Ti substrate surface. Their growth orientation predominantly depends on the local electric field around the bottom of the nanotube. The distribution of the local electric field is regulated by the shape of the initial nano-scale local Ti substrate surface (INLTSS). Most of the INLTSS is nearly flat, which leaves vertical, circular, and straight TNTs. In terms of the evolution of TNTs fabricated on a micron-scale convex surface, the vertical growth of TNTs leads to a continuous decrease in the oxide/substrate (O/S) interface area, and a few TNTs are periodically crushed and detached from the O/S interface. For a micron-scale concave surface, due to the ever-increasing O/S interface area, Y-branched TNTs occurred periodically as a response to avoid a vacancy on the oxide/substrate interface.

[Hybrid Electric Bus SCR System Operation and NOx Emission Characteristics Based on Remote Communication Technology].

The selective catalytic reduction system (SCR) is an essential method to reduce NOx emissions from heavy-duty diesel engine-powered vehicles, which include conventional diesel buses and diesel-electric hybrid buses. Using wireless remote communication technology, the SCR system status and NOx emissions were reviewed for ten fully-operational hybrid buses from Hangzhou China in this research. Under the internal combustion engine mode, the main factors studied were vehicle speed, engine operation conditions and environment temperature, impact on the SCR catalyst outlet temperature and NOx concentration and dosing rate of the urea injector of the SCR system. The research result shows that (32.4±4)% of the operational time of the hybrid buses with SCR system was spent in internal combustion engine mode, and under (26.9±11)% of the operation time of this mode, the SCR system did not dose urea. The average NOx emission reduction rate of the SCR system, when operating normally with hybrid buses, is about 59%. The main reasons for the high NOx emission of the diesel-electric hybrid buses in operation condition are poor satisfaction of the requirements of the SCR system control strategy and the SCR catalyst's low temperature conversion efficiency. Whenever the speed of the hybrid buses was above 40 km·h-1, the SCR catalyst outlet temperatures were higher than the 230℃, and the NOx emission concentrations were significantly reduced, as the urea injector working proportion and urea quantity increased. In the winter, the SCR catalyst outlet temperature and urea injection quantity dropped with the reduced environment temperature, which led to increased NOx emissions.

Chimeric classical swine fever (CSF)-Japanese encephalitis (JE) viral replicon as a non-transmissible vaccine candidate against CSF and JE infections.

A trans-complemented chimeric CSF-JE virus replicon was constructed using an infectious cDNA clone of the CSF virus (CSFV) Alfort/187 strain. The CSFV E2 gene was deleted, and a fragment containing the region encoding a truncated envelope protein (tE, amino acid 292-402, domain III) of JE virus (JEV) was inserted into the resultant plasmid, pA187delE2, to generate the recombinant cDNA clone pA187delE2/JEV-tE. Porcine kidney 15 (PK15) cells that constitutively express the CSFV E2p7 proteins were then transfected with in vitro-transcribed RNA from pA187delE2/JEV-tE. As a result, the chimeric CSF-JE virus replicon particle (VRP), rv187delE2/JEV-tE, was rescued. In a mouse model, immunization with the chimeric CSF-JE VRP induced strong production of JEV-specific antibody and conferred protection against a lethal JEV challenge. Pigs immunized with CSF-JE VRP displayed strong anti-CSFV and anti-JEV antibody responses and protection against CSFV and JEV challenge infections. Our evidence suggests that E2-complemented CSF-JE VRP not only has potential as a live-attenuated non-transmissible vaccine candidate against CSF and JE but also serves as a potential DIVA (Differentiating Infected from Vaccinated Animals) vaccine for CSF in pigs. Together, our data suggest that the non-transmissible chimeric VRP expressing foreign antigenic proteins may represent a promising strategy for bivalent DIVA vaccine design.

Transmission of avian H9N2 influenza viruses in a murine model.

Avian H9N2 influenza viruses have circulated widely in domestic poultry around the world, resulting in occasional transmission of virus from infected poultry to humans. However, it is unknown whether H9N2 influenza virus has acquired the ability to be transmitted from human to human. Here, we report that mouse-adapted H9N2 influenza viruses can replicate efficiently and are lethal for several strains of mice. To evaluate the transmissibility of mouse-adapted H9N2 influenza viruses, we carried out transmission studies in mice using both contact and respiratory droplet routes. Our results indicate that mouse-adapted H9N2 influenza viruses can replicate efficiently and be transmitted between mice. This suggests that once H9N2 influenza viruses adapt to new host, they should present potential public health risks, therefore, urgent attention should be paid to H9N2 influenza viruses.

Multiple amino acid substitutions are involved in the adaptation of H9N2 avian influenza virus to mice.

To explore adaptation of avian influenza virus to mice we previously performed serial lung-to-lung passages of the influenza A/Chicken/Jiangsu/7/2002 (H9N2) strain, resulting in the isolation of a variant influenza strain lethal for mice. We now report that virulence correlates with improved growth characteristics on mammalian cells and extended tissue tropism in vivo. Sequencing of the complete genomes of the wild-type and mouse-adapted viruses revealed 25 amino acid substitutions. Some were found to reiterate known substitutions in human and swine H9N2 influenza isolates. Functions affected include nuclear localization signals and sites of protein and RNA interaction, while others are known determinants of pathogenicity and host specificity such as the viral polymerase PB2 E627K substitution. These observations suggest that enhanced growth characteristics and modified cell tropism may contribute to increased virulence in mice. We conclude that multiple amino acid substitutions are likely to be involved in the adaptation of H9N2 avian influenza virus to mice.

[Study on the technics of adsorption and purification of baicalin by different macroporous resins].

OBJECTIVE: To ascertain the fittest technical parameters by studying the application of macroporous resins used to purify active components of baicalin. METHODS: To evaluate the ability of adsorption and re-adsorption of macroporous resins selected, the statical and dynamic adsorption-readsorption durations were also investigated to select the optimum macroporous resins, with the content of flavonoids as the standard. RESULTS: The optimum macroporous resins was HPD-100. In the adsorption cours, the ratio between the amount of medicinal materials and the volume of macroporous resins was 3.0 and there was no more absorbed when the ratio was 12.5; the optimum ethanol concentration was 50% in readsorption duration. CONCLUSION: HPD-100 is the optimum macroporous resin to purify bailcalin and enhance its refined rate.