Sampling expansions associated with quaternion difference equations

Starting with a quaternion difference equation with boundary conditions, a parameterized sequence which is complete in finite dimensional quaternion Hilbert space is derived. By employing the parameterized sequence as the kernel of discrete transform, we form a quaternion function space whose elements have sampling expansions. Moreover, through formulating boundary-value problems, we make a connection between a class of tridiagonal quaternion matrices and polynomials with quaternion coefficients. We show that for a tridiagonal symmetric quaternion matrix, one can always associate a quaternion characteristic polynomial whose roots are eigenvalues of the matrix. Several examples are given to illustrate the results

1D and 2D Cobalt(II) coordination polymers with dipicolinic acid ligands and photocatalytic CO2 reduction

356-3601D and 2D cobalt(II) coordination polymers, [Co(2,3-dpc)(H2O)2]n (1), [Co(2,5-dpc)(H2O)3]n (2) and [Co(3,5-dpc)(H2O)2]n (3) (dpc = dipicolinic acid dianion) have been successfully synthesized by reaction of dipicolinic acid ligands with CoF2 in aqueous methanolic solution under hydrothermal conditions. High resolution mass spectroscopy investigation reveals the forming process of CO during the photocatalytic CO2 reduction and the plausible mechanisms are proposed

Two jasmonic acid carboxyl methyltransferases in Gossypium hirsutum involved in MeJA biosynthesis may contribute to plant defense

Jasmonic acid (JA) and methyl jasmonate (MeJA), the crucial plant hormones, can induce the emission of plant volatiles and regulate the behavioral responses of insect pests or their natural enemies. In this study, two jasmonic acid carboxyl methyltransferases (JMTs), GhJMT1 and GhJMT2, involved in MeJA biosynthesis in Gossypium. hirsutum were identified and further functionally confirmed. In vitro, recombinant GhJMT1 and GhJMT2 were both responsible for the conversion of JA to MeJA. Quantitative real-time PCR (qPCR) measurement indicated that GhJMT1 and GhJMT2 were obviously up-regulated in leaves and stems of G. hirsutum after being treated with MeJA. In gas chromatography-mass spectrometry (GC-MS) analysis, MeJA treatment significantly induced plant volatiles emission such as (E)-β-ocimene, (Z)-3-hexenyl acetate, linalool and (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), which play vital roles in direct and indirect plant defenses. Moreover, antennae of parasitoid wasps Microplitis mediator showed electrophysiological responses to MeJA, β-ocimene, (Z)-3-hexenyl acetate and linalool at a dose dependent manner, while our previous research revealed that DMNT excites electrophysiological responses and behavioral tendencies. These findings provide a better understanding of MeJA biosynthesis and defense regulation in upland cotton, which lay a foundation to JA and MeJA employment in agricultural pest control

Study on the Effect of NTO on the Performance of HMX-Based Aluminized Cast-PBX

3-Nitro−1,2,4-triazol−5-one (NTO) is an explosive with broad application prospects. To study the effect of NTO content on the properties of HMX-based cast-PBX (polymer bonded explosive), five different HMX/NTO-based cast-PBXs were prepared and characterized by experiments and simulations. The results show that the addition of NTO is beneficial to reduce the mechanical sensitivity of cast-PBX, but will reduce the energy level of cast-PBX. We then found that with the increase in NTO content, cast-PBX showed a trend of first increasing and then decreasing in terms of mechanical properties, specific heat capacity (Cp) and thermal conductivity (λ). In addition, we found that the Gurney energy (Eg) of N30 is 2.31 kJ/g. Finally, the increase in NTO content greatly improves the thermal safety performance of the cast-PBXs, and numerical simulation of slow cook-off can be used as one reliable method to obtain the ignition location, ignition temperature and the transient temperature distribution

A recombinant multi-epitope protein MEP1 elicits efficient long-term immune responses against HIV-1 infection

The effective protective HIV vaccine should elicit either protective antibodies or effective T cell response, or both. To improve the efficacy of HIV-1 vaccines, HLA polymorphism and HIV-1 diversity are 2 key factors to be considered for vaccine development. In this study, we expressed a recombinant multi-epitope protein MEP1 which has the same amino acid sequence as a DNA vaccine for Chinese population in our previous report. We found that MEP1 alone could elicit moderate levels of humoral and cellular immune responses, but these responses could not provide protection from challenge with a recombinant virus rTTV-lucgag, which expresses Gag of HIV-1 CRF_07BC. Nevertheless, when MEP1 was immunized with aluminum adjuvant, both humoral and cellular immune responses were significantly increased, and they were protective against virus infection; meanwhile, MEP1 with aluminum not only elicited early (10 d post immunization) but also a long-term (at least 44 weeks post immunization) immune responses in BALB/c mice. These results suggested that MEP1 has the potential to be developed as an effective vaccine candidate, and that suitable adjuvant is necessary for this protein to generate protective immune responses

Pitting Corrosion of Natural Aged Al–Mg–Si Extrusion Profile

With the quick development of the high-speed railway and the service of the China Railway High-speed (CRH) series for almost a decade, one of the greatest challenges is the management/maintenance of these trains in environmental conditions. It is critical to estimate pitting damage initiation and accumulation and set up a corresponding database in order to support the foundations for interactive corrosion risk management. In this work, the pitting corrosion of a nature-aged commercial 6005A-T6 aluminum extrusion profile for 200 days was studied comprehensively. The heterogeneous microstructures were conventionally identified by the in situ eddy current, suggesting which investigated regions to fabricate samples for. After constant immersion for 240 h in 3.5 wt % NaCl, the shapes and depths of the pits were captured and measured by optical microscope (OM) and three-dimensional optical profilometry (OP), providing detailed quantification of uniform pitting corrosion. The typical features of the pits dominated by the distribution of precipitates include the peripheral dissolution of the Al matrix, channeling corrosion, intergranular attack, and large pits in the grains. Due to the high density of continuous anodic and cathodic particles constituted by alloying elements in coarse grains, the number of pits in the coarse grains was the highest while the number in the fine grains was the lowest, indicating that fine grains have the best corrosion resistance. The experimental dataset of the pit depth integrated with its corresponding microstructure would set the benchmark for further modeling of the pit depth and the remaining ductility, in order to manage the damage tolerance of the materials

Multi-Organ Damage in Human Dipeptidyl Peptidase 4 Transgenic Mice Infected with Middle East Respiratory Syndrome-Coronavirus.

The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) causes severe acute respiratory failure and considerable extrapumonary organ dysfuction with substantial high mortality. For the limited number of autopsy reports, small animal models are urgently needed to study the mechanisms of MERS-CoV infection and pathogenesis of the disease and to evaluate the efficacy of therapeutics against MERS-CoV infection. In this study, we developed a transgenic mouse model globally expressing codon-optimized human dipeptidyl peptidase 4 (hDPP4), the receptor for MERS-CoV. After intranasal inoculation with MERS-CoV, the mice rapidly developed severe pneumonia and multi-organ damage, with viral replication being detected in the lungs on day 5 and in the lungs, kidneys and brains on day 9 post-infection. In addition, the mice exhibited systemic inflammation with mild to severe pneumonia accompanied by the injury of liver, kidney and spleen with neutrophil and macrophage infiltration. Importantly, the mice exhibited symptoms of paralysis with high viral burden and viral positive neurons on day 9. Taken together, this study characterizes the tropism of MERS-CoV upon infection. Importantly, this hDPP4-expressing transgenic mouse model will be applicable for studying the pathogenesis of MERS-CoV infection and investigating the efficacy of vaccines and antiviral agents designed to combat MERS-CoV infection