240 research outputs found
Metal Amidoboranes and Their Derivatives for Hydrogen Storage
As potential hydrogen storage mediums, ammonia borane and its derivatives have been paid an increasing attention owing to their higher hydrogen capacities and facile dehydrogenation properties under moderate conditions. In this chapter, we presented extensive studies on thermodynamic tailoring of dehydrogenation of metal amidoboranes, metal borohydride-ammonia borane complexes, and metal amidoborane ammoniates as well as their derivatives, with special focus on the syntheses, crystal structures, and dehydrogenation properties. Finally, future perspective was given toward the practical applications
Asymmetric cryorolling for fabrication of nanostructural aluminum sheets
Nanostructural Al 1050 sheets were produced using a novel method of asymmetric cryorolling under ratios of upper and down rolling velocities (RUDV) of 1.1, 1.2, 1.3, and 1.4. Sheets were rolled to about 0.17 mm from 1.5 mm. Both the strength and ductility of Al 1050 sheets increase with RUDVs. Tensile strength of Al sheets with the RUDV 1.4 is larger 22.3% of that for RUDV 1.1, which is 196 MPa. The TEM observations show the grain size is 360 nm when the RUDV is 1.1, and 211 nm for RUDV 1.4
Assessment of the osteogenic effect after maxillary sinus floor elevation and simultaneous implantation with or without bone grafts by analyzing trabecular bone parameters: a retrospective study
Objective: The aim of this population-based retrospective study was to compare the osteogenic effect of newly formed bone after maxillary sinus floor elevation (MSFE) and simultaneous implantation with or without bone grafts by quantitatively analyzing trabecular bone parameters. Methodology:A total of 100 patients with missing posterior maxillary teeth who required MSFE and implantation were included in this study. Patients were divided into two groups: the non-graft group (n=50) and the graft group (n=50). Radiographic parameters were measured using cone beam computed tomography (CBCT), and the quality of newly formed bone was analyzed by assessing trabecular bone parameters using CTAn (CTAnalyzer, SkyScan, Antwerp, Belgium) software. Results: In the selected regions of interest, the non-graft group showed greater bone volume/total volume (BV/TV), bone surface/total volume (BS/TV), trabecular number (Tb. N), and trabecular thickness (Tb. Th) than the graft group (p<0.001). The non-graft group showed lower trabecular separation (Tb. Sp) than the graft group (p<0.001). The incidence of perforation and bleeding was higher in the graft group than in the non-graft group (p<0.001), but infection did not significantly differ between groups (p>0.05). Compared to the graft group, the non-graft group showed lower postoperative bone height, gained bone height and apical bone height (p<0.001). Conclusion: MSFE with and without bone grafts can significantly improve bone formation. In MSFE, the use of bone grafts hinders the formation of good quality bone, whereas the absence of bone grafts can generate good bone quality and limited bone mass
PB2 segment promotes high-pathogenicity of H5N1 avian influenza viruses in mice
H5N1 influenza viruses with high lethality are a continuing threat to humans and poultry. Recently, H5N1 high-pathogenicity avian influenza virus (HPAIV) has been shown to transmit through aerosols between ferrets in lab experiments by acquiring some mutation. This is another deeply aggravated threat of H5N1 HPAIV to humans. To further explore the molecular determinant of H5N1 HPAIV virulence in a mammalian model, we compared the virulence of A/Duck/Guangdong/212/2004 (DK212) and A/Quail/Guangdong/90/2004 (QL90). Though they were genetically similar, they had different pathogenicity in mice, as well as their 16 reassortants. The results indicated that a swap of the PB2 gene could dramatically decrease the virulence of rgDK212 in mice (1896-fold) but increase the virulence of rgQL90 in mice (60-fold). Furthermore, the polymerase activity assays showed that swapping PB2 genes between these two viruses significantly changed the activity of polymerase complexes in 293T cells. The mutation Ser715Asn in PB2 sharply attenuated the virulence of rgDK212 in mice (2710-fold). PB2 segment promotes high-pathogenicity of H5N1 avian influenza viruses in mice and 715 Ser in PB2 plays an important role in determing high virulence of DK212 in mice
A quantitative RT-PCR assay for rapid detection of Eurasianlineage H10 subtype influenza A virus
Influenza A viruses (IAVs) are single-stranded, negative sense RNA viruses. IAV subtype is determined on the basis of the viral surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA). To date, 18 HA and 11 NA subtypes have been reported (Tong et al., 2012). IAVs can cause sporadic infections, local epidemics, and global pandemics among humans. In addition to humans, IAVs can naturally infect avian, swine, equines, canines, and sea mammals (Webster et al., 1992). Migratory waterfowl are the natural reservoir for IAVs, and the avianorigin IAVs play an important role in influenza ecology and have been involved in generation of the IAVs infection in humans. At least one or more genetic segments of all four known pandemic strains are of avian origin, and these avian-origin genes reassorted with those IAVs from domestic animals to generate pandemic viruses. For example, the HA genes (major antigenic determinants) of 1918, 1957, and 1968 pandemic viruses are all of avianorigin (Webster et al., 1997); the 2009 H1N1 pandemic virus has avian-origin PB2 and PA genes (Shinde et al., 2009). Besides pandemic viruses, in the past decades, there have also been a number of reported human infections with avian IAVs, including subtypes H5N1, H6N1, H7N2, H7N3, H7N7, H9N2, H10N7 and H7N9. Thus, monitoring the evolution of avian IAVs and rapidly detecting these viruses in human are important components of influenza surveillance and pandemic preparedness
A quantitative RT-PCR assay for rapid detection of Eurasianlineage H10 subtype influenza A virus
Influenza A viruses (IAVs) are single-stranded, negative sense RNA viruses. IAV subtype is determined on the basis of the viral surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA). To date, 18 HA and 11 NA subtypes have been reported (Tong et al., 2012). IAVs can cause sporadic infections, local epidemics, and global pandemics among humans. In addition to humans, IAVs can naturally infect avian, swine, equines, canines, and sea mammals (Webster et al., 1992). Migratory waterfowl are the natural reservoir for IAVs, and the avianorigin IAVs play an important role in influenza ecology and have been involved in generation of the IAVs infection in humans. At least one or more genetic segments of all four known pandemic strains are of avian origin, and these avian-origin genes reassorted with those IAVs from domestic animals to generate pandemic viruses. For example, the HA genes (major antigenic determinants) of 1918, 1957, and 1968 pandemic viruses are all of avianorigin (Webster et al., 1997); the 2009 H1N1 pandemic virus has avian-origin PB2 and PA genes (Shinde et al., 2009). Besides pandemic viruses, in the past decades, there have also been a number of reported human infections with avian IAVs, including subtypes H5N1, H6N1, H7N2, H7N3, H7N7, H9N2, H10N7 and H7N9. Thus, monitoring the evolution of avian IAVs and rapidly detecting these viruses in human are important components of influenza surveillance and pandemic preparedness
A quantitative RT-PCR assay for rapid detection of Eurasianlineage H10 subtype influenza A virus
Influenza A viruses (IAVs) are single-stranded, negative sense RNA viruses. IAV subtype is determined on the basis of the viral surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA). To date, 18 HA and 11 NA subtypes have been reported (Tong et al., 2012). IAVs can cause sporadic infections, local epidemics, and global pandemics among humans. In addition to humans, IAVs can naturally infect avian, swine, equines, canines, and sea mammals (Webster et al., 1992). Migratory waterfowl are the natural reservoir for IAVs, and the avianorigin IAVs play an important role in influenza ecology and have been involved in generation of the IAVs infection in humans. At least one or more genetic segments of all four known pandemic strains are of avian origin, and these avian-origin genes reassorted with those IAVs from domestic animals to generate pandemic viruses. For example, the HA genes (major antigenic determinants) of 1918, 1957, and 1968 pandemic viruses are all of avianorigin (Webster et al., 1997); the 2009 H1N1 pandemic virus has avian-origin PB2 and PA genes (Shinde et al., 2009). Besides pandemic viruses, in the past decades, there have also been a number of reported human infections with avian IAVs, including subtypes H5N1, H6N1, H7N2, H7N3, H7N7, H9N2, H10N7 and H7N9. Thus, monitoring the evolution of avian IAVs and rapidly detecting these viruses in human are important components of influenza surveillance and pandemic preparedness
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