Search

Gold coatings are the most widely used protective layer for resisting surface oxidization and corrosion in various complex environments. However, the extremely low hardness, inferior load‐bearing capacity, and lack of an effective strategy for evaluating the elastic‐plastic behavior of gold coatings have greatly limited their further application. The main aim of this work is to investigate the effect of Ni doping on the microstructure, mechanical properties, and electrical contact stability of a coating based on an experimental method and finite element simulation. The strain‐hardening exponent model of the coating is established by employing a reverse analysis method based on the nanoindentation experiment until the reverse and forward loading curves are consistent, thereby determining the yield strength. The results indicate that Ni doping is conducive to enhancing the mechanical properties under the premise of ensuring low contact resistance. The hardness (3.3–4.2 GPa) and yield strength (524.3–689.8 MPa) of the Au1−xNix composite coating with a Ni content of 4 at–8 at% is more than twice as high as that of pure Au. The electrical contacts deposited by the Au1−xNix coatings maintain a low contact resistance range (1.12–3.29 mΩ) at a contact force of 10 gf. [ABSTRACT FROM AUTHOR]

HIV-1 is a highly host-specific retrovirus that infects humans but not most nonhuman primates. Thus, the lack of a suitable primate model that can be directly infected with HIV-1 hinders HIV-1/AIDS research. In the previous study, we have found that the northern pig-tailed macaques (NPMs) are susceptible to HIV-1 infection but show a nonpathogenic state. In this study, to understand this macaque–HIV-1 interaction, we assembled a de novo genome and longitudinal transcriptome for this species during the course of HIV-1 infection. Using comparative genomic analysis, a positively selected gene, Toll-like receptor 8, was identified with a weak ability to induce an inflammatory response in this macaque. In addition, an interferon-stimulated gene, interferon alpha inducible protein 27, was upregulated in acute HIV-1 infection and acquired an enhanced ability to inhibit HIV-1 replication compared with its human ortholog. These findings coincide with the observation of persistently downregulated immune activation and low viral replication and can partially explain the AIDS-free state in this macaque following HIV-1 infection. This study identified a number of unexplored host genes that may hamper HIV-1 replication and pathogenicity in NPMs and provided new insights into the host defense mechanisms in cross-species infection of HIV-1. This work will facilitate the adoption of NPM as a feasible animal model for HIV-1/AIDS research. [ABSTRACT FROM AUTHOR]

Pulmonary microbial invasion frequently occurs during AIDS progression in HIV patients. Inflammatory cytokines and other immunoregulatory factors play important roles in this process. We previously established an AIDS model of SIVmac239 infection in northern pig-tailed macaques (NPMs), which were divided into rapid progressor (RP) and slow progressor (SP) groups according to their AIDS progression rates. In this study, we performed 16S rDNA and transcriptome sequencing of the lungs to reveal the molecular mechanism underlying the difference in progression rate between the RPs and SPs. We found that microbial invasion in the RP group was distinct from that in the SP group, showing marker flora of the Family XI, Enterococcus and Ezakiella, and more Lactobacilli. Through pulmonary transcriptome analysis, we found that the transcription factor ZNF683 had higher expression in the SP group than in the RP group. In subsequent functional experiments, we found that ZNF683 increased the proliferation and IFNγ secretion ability of CD8+ T cells, thus decreasing SIV or HIV replication, which may be related to AIDS progression in SIVmac239-infected NPMs. This study helps elucidate the various complexities of disease progression in HIV-1-infected individuals. [ABSTRACT FROM AUTHOR]

Although spermatogenic dysfunction is widely found in patients with human immunodeficiency virus (HIV), the underlying reasons remain unclear. Thus far, potential hypotheses involving viral reservoirs, testicular inflammation, hormone imbalance, and cachexia show inconsistent correlation with spermatogenic dysfunction. Here, northern pig-tailed macaques (NPMs) exhibited marked spermatogenic dysfunction after long-term infection with simian immunodeficiency virus (SIVmac239), with significant decreases in Johnsen scores, differentiated spermatogonial stem cells, and testicular proliferating cells. The above hypotheses were also evaluated. Results showed no differences between SIV− and SIV+ NPMs, except for an increase in follicle stimulating hormone (FSH) during SIV infection, which had no direct effect on the testes. However, long-term SIVmac239 infection undermined pancreatic islet β cell function, partly represented by significant reductions in cellular counts and autophagy levels. Pancreatic islet β cell dysfunction led to glucose metabolism disorder at the whole-body level, which inhibited lactate production by Sertoli cells in testicular tissue. As lactate is the main energy substrate for developing germ cells, its decrease was strongly correlated with spermatogenic dysfunction. Therefore, glucose metabolism disorder appears to be a primary cause of spermatogenic dysfunction in NPMs with long-term SIVmac239 infection. [ABSTRACT FROM AUTHOR]

Macaca leonina (northern pig-tailed macaques, NPMs) have variable disease progression during SIVmac239 infection. In the present study, we analysed, for the first time, the correlations between T-cell phenotypes and disease progression in NPMs during SIVmac239 infection. In comparison to normal progressors (NPs), slow progressors (SPs) had lower chronic T-cell activation and exhaustion levels. In addition, SPs showed higher peripheral CD4+ T-cell count and CD4 : CD8 ratio, and lower plasma viral load than NPs. CD4+ T-cell count and CD4 : CD8 ratio decreased more sharply in NPs than in SPs. Furthermore, T cells in NPs were more highly differentiated, at least in acute infection, than in SPs. These results indicated that T-cell phenotypes were correlated with disease progression in SIVmac239-infected NPMs and these correlations may provide valuable guidance for the improvement of therapeutic strategies tested in NPMs. [ABSTRACT FROM AUTHOR]

Non-human primates are natural virus reservoirs, whether wild or domestic. In this study, we determined the seroprevalence of common viruses by ELISA in a northern pig-tailed macaque ( Macaca leonina) colony derived from Ho Chi Minh City, Vietnam. A total of 20 types of virus which are commonly selected as target microorganisms for specific-pathogen-free colonies, or which have zoonotic potential were included in this study. The results showed only 2 in 90 northern pig-tailed macaques were seronegative for all the detected viruses, and at least 16 out of the total 20 types of virus tested were prevalent in this colony, so these macaques were commonly infected by various viruses. These macaques should be carefully assessed for viral seroprevalence in order to prevent zoonotic diseases from being transferred to human beings. [ABSTRACT FROM AUTHOR]

Chinese rhesus macaques (CRMs) are ideal experimental animals for studying the pathogenesis of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) and for vaccine research. SHIV89.6 has been reported to be an attenuated virus because, in most cases, SHIV89.6 infection only causes limited alteration of immune cells and tissues, and it has been used commonly for vaccine research. After two serial passages in vivo, SHIV (SHIV-89.6P) induces CD4 lymphopenia and an AIDS-like disease with wasting and opportunistic infections. However, the pathogenic ability of SHIV89.6 is not well understood. In this study, we found that 6 of 14 SHIV89.6-infected CRMs died within 127 weeks after infection. We found especially high immune activation, low IFN-α expression, and distinctive cytokine expression profiles in the infected and dead (ID) group of monkeys, while there was only few change in the CD4 T counts and distribution of T cell subsets in the ID group monkeys. Also, there was a similar dynamic of viral load between infected and surviving (IS) and ID group monkeys. Furthermore, we found various correlations among immune activation, IFN-α expression, and frequencies of cytokine-secreting cells. These results suggest that SHIV89.6 infections have pathogenic potential in CRMs and that high immune activation and abnormal expression of cytokines contribute to death of SHIV89.6-infected CRMs. This also implies that high immune activation may be relevant to dysfunction of immune cells. It is proposed that high immune activation and dysfunction of immune cells may be good predictors for disease progression and markers for therapy. [ABSTRACT FROM AUTHOR]

A novel polyhedral oligomeric silsesquioxane/polymethyl methacrylate (POSS/ PMMA) hybrid nanocomposite was synthesized by using potassium persulfate and sodium dodecyl sulfate as the initiator and emulsifier, respectively. The structures of prepared nanocomposites were characterized with X-ray photoelectron spectroscopy, laser particle size analysis, and X-ray diffraction. The thermal properties of the POSS/PMMA nanocomposites were studied by differential scanning calorimetry, and thermogravimetric analysis. The results indicate that POSS could be incorporated into the PMMA matrix at molecular lever and the incorporation of POSS molecules can improve the thermal stability of PMMA. [Supplemental materials are available for this article. Go to the publisher's online edition ofPhosphorus, Sulfur, and Silicon and the Related Elementsto view the following free supplemental files: Additional figures] [ABSTRACT FROM PUBLISHER]

The distribution characteristics of heavy metals in soil-root systems have great significance for the research into soil pollution risk assessment and the phytoremediation effect. This paper takes ligustrum lucidum as an example, based on the characteristics of adsorption of heavy metals in soil by woody plants, lays out sampling points, and using software Sufer for the Kiging interpolation analysis, and the horizontal migration law of heavy metal cadmium in the soil-root interface system is simulated. Through multi-model statistical regression trend analysis, the horizontal migration mechanism of cadmium in different sections is discussed. The results show that: ① under horizontal migration law: the migration ability of Cd is weaker near the Ligustrum lucidum root (0-30 cm); with the root extension, the migration ability of Cd gradually is strengthened, and the main range of the migration ability is 60-90 cm. In addition, its migration law follows the cubic curve mode. ② under longitudinal migration law: based on the Kriging method, migration models Z( h) of heavy metal Cd in any depth of h are constructed and fit the correlation coefficient R>0.95. [ABSTRACT FROM AUTHOR]

Nanocrystalline Ni1− x Zn x Fe2 O4 (0 ≤ x ≤ 1.0) powder with grain size of 30 nm was prepared using the spraying-coprecipitation method. The obtained nanocrystalline Ni1− x Zn x Fe2 O4 powder was sintered using conventional and microwave sintering techniques. The results show that the microstructure and magnetic properties of the sintered samples are obviously improved by microwave sintering of nanocrystalline Ni1− x Zn x Fe2 O4 ferrite powder. The initial permeability of Ni1− x Zn x Fe2 O4 ferrite increases with the increase in zinc concentration, although its resonance frequencies shift from high frequency to low frequency. The maximum initial permeability for microwave-sintered Ni0.4 Zn0.6 Fe2 O4 ceramic obtained at the temperature of 1170°C for 30 min reaches up to 360.9, and its resonance frequency is ~10 MHz. It may be attributed to the nanocrystalline Ni1− x Zn x Fe2 O4 raw powder as well as the microwave sintering process, which results in a synergistic effect on improvement of the microstructure and magnetic properties. [ABSTRACT FROM AUTHOR]

Immune activation plays a significant role in the disease progression of HIV. Microbial products, especially bacterial lipopolysaccharide (LPS), contribute to immune activation. Increasing evidence indicates that T lymphocyte homeostasis disruptions are associated with immune activation. However, the mechanism by which LPS affects disruption of immune response is still not fully understood. Chronically SHIVB'WHU-infected Chinese rhesus macaques received 50 μg/kg body weight LPS in this study. LPS administration affected the virus/host equilibrium by elevating the levels of viral replication and activating T lymphocytes. LPS induced upregulation of CD8(+) naïve T cells and downregulated the number of CD4(+) and CD8(+) T effector memory cells. The downregulated effector memory cells are associated with a lower frequency of monofunctional and polyfunctional cells, and an upregulated programmed cell death-1 (PD-1) expression on CD4(+) and CD8(+) T cells was observed in monkeys after LPS stimulation. Our data provide new insights into the function of LPS in the immune activation in SHIV/HIV infection. [ABSTRACT FROM AUTHOR]