96 research outputs found

    Garnierite mineralization from a serpentinite-derived lateritic regolith, Sulawesi Island, Indonesia: Mineralogy, geochemistry and link to hydrologic flow regime

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    Garnierite represents a significant nickel ore in many lateritic Ni deposits worldwide. To gain a better understanding of its nature and origin, a well-developed garnierite-hosting transect from the Kolonodale area of East Sulawesi, Indonesia, has been investigated using field geology, mineralogy and geochemical data. Garnierite occurs mainly in veins in the lower saprolite of a serpentinite-derived regolith. Mineralogically, it can be determined as an intimate mixture of Ni-rich serpentine-like (lizardite-Nepouite) and talc-like (kerolite-pimelite) phases. Results of EMP analyses indicate that Ni is preferentially enriched in the talc-like phases rather than the serpentine-like phases. A sequential precipitation of mineral phases progressively enriched in Ni and Si to form garnierite during weathering is suggested. The Ni-lizardite (2.63-8.49 wt% Ni) with elevated Fe (4.02-6.44 wt %) may have been inherited from saprolite in a first instance and enriched in Ni by cation exchange processes. Newly precipitated minerals are kerolite-pimelite (7.84-23.54 wt% Ni) and then followed by Ni-free quartz. Minor amount of Nepouite (23.47-28.51 wt% Ni) occur in laths along shrinkage cracks of previously formed minerals, indicating a late stage paragenetic sequence. With emphasis on a hydrologic consideration, indicators of a preferential flow regime are identified in the garnierite-hosting regolith, including: (i) non-uniform pattern of the garnierite field occurrence, (ii) syn-weathering active nature of the garnierite-hosting structures, (iii) close relationship between the garnierite occurrence and vertical FeeMn oxides pipes as well as FeeMn oxides patched areas, and (iv) specific physico-chemical property of the garnierite location with higher organic matter concentrations but lower pH values compared to surroundings. It is proposed that the origin of garnierite is closely linked to a preferential flow of oversaturated solutions through accessible conduits in the regolith. Garnierite features as colloidal nature, high organic matter and low pH are key-parameters in metal transport and deposition

    Metformin downregulates PD-L1 expression in esophageal squamous cell catrcinoma by inhibiting IL-6 signaling pathway

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    Purpose: To characterize the mechanism by which metformin inhibits PD-L1 expression in esophageal squamous cell carcinoma (ESCC) and to evaluate the effect of metformin on the antitumor immune response. Methods: The Cancer Genome Atlas (TCGA) database was used to analyze the correlations between IL-6 and prognosis and between IL-6 and PD-L1 gene expression in esophageal cancer. Reverse transcription-quantitative polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence were used to study the mechanism by which metformin affects PD-L1 expression. Additionally, T cell function was assessed in a coculture system containing ESCC cells and peripheral blood mononuclear cells (PBMCs) treated with metformin or IL-6. In an Results: The TCGA esophageal cancer data showed that IL-6 expression was positively correlated with PD-L1 expression and that patients with high IL-6 expression had a significantly lower overall survival rate than patients with low IL-6 expression. PD-L1 expression in ESCC cell lines was significantly inhibited by metformin Conclusions: Metformin downregulated PD-L1 expression by blocking the IL-6/JAK2/STAT3 signaling pathway in ESCC, which enhanced the antitumor immune response

    Design and analysis of a flextensional piezoelectric actuator for incus-body driving type middle ear implant

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    In order to decrease the power consumption of current piezoelectric stack actuator for incus-body driving type middle ear implant (MEI), a new MEI’s piezoelectric actuator with a flextensional amplifier was proposed. To aid the design process of this actuator, a human middle-ear mechanical model, which incorporated the viscoelastic properties of middle ear soft tissues, was established using finite element method. And the validation of this model was confirmed by comparing the model-predicted results with temporal bone experimental data. Then, based on this model, a coupling mechanical model of the flextensional piezoelectric actuator and the human ear was constructed and used to study the equivalent sound pressure level and power consumption of the actuator. The results show that the hearing compensation performance of the piezoelectric actuator was improved by introducing the flextensional amplifier, and the power consumption of the actuator was reduced significantly

    Can patient gratitude expression boost innovative performance? The role of work meaningfulness and supervisory support

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    Based on emotions as social information (EASI) theory, the current study proposed how and when patient gratitude expression could promote nurses’ innovative performance. Using a time-lagged data of 649 nurses from three class A tertiary hospitals in China, the results showed that patient gratitude expression was positively related to nurses’ innovative performance, and nurses’ work meaningfulness mediated such effect. Furthermore, supervisory support moderated the relationship of work meaningfulness with nurses’ innovative performance, as well as the indirect relationship between patient gratitude expression and innovative performance through work meaningfulness, such that the indirect relationship was stronger when supervisory support is higher. Our research helps to expand our understanding of how patient gratitude expression as an organizational external factor influences nurses’ innovation in healthcare, and meanwhile, provides management insights for hospital managers to focus on patient gratitude expression and enhance nurse innovation

    SIRT5 promotes IDH2 desuccinylation and G6PD deglutarylation to enhance cellular antioxidant defense

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    Abstract Excess in mitochondrial reactive oxygen species (ROS) is considered as a major cause of cellular oxidative stress. NADPH, the main intracellular reductant, has a key role in keeping glutathione in its reduced form GSH, which scavenges ROS and thus protects the cell from oxidative damage. Here, we report that SIRT5 desuccinylates and deglutarylates isocitrate dehydrogenase 2 (IDH2) and glucose‐6‐phosphate dehydrogenase (G6PD), respectively, and thus activates both NADPH‐producing enzymes. Moreover, we show that knockdown or knockout of SIRT5 leads to high levels of cellular ROS. SIRT5 inactivation leads to the inhibition of IDH2 and G6PD, thereby decreasing NADPH production, lowering GSH, impairing the ability to scavenge ROS, and increasing cellular susceptibility to oxidative stress. Our study uncovers a SIRT5‐dependent mechanism that regulates cellular NADPH homeostasis and redox potential by promoting IDH2 desuccinylation and G6PD deglutarylation

    The New Is Old: Novel Germination Strategy Evolved From Standing Genetic Variation in Weedy Rice

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    Feralization of crop plants has aroused an increasing interest in recent years, not only for the reduced yield and quality of crop production caused by feral plants but also for the rapid evolution of novel traits that facilitate the evolution and persistence of weedy forms. Weedy rice (Oryza sativa f. spontanea) is a conspecific weed of cultivated rice, with separate and independent origins. The weedy rice distributed in eastern and northeastern China did not diverge from their cultivated ancestors by reverting to the pre-domestication trait of seed dormancy during feralization. Instead, they developed a temperature-sensing mechanism to control the timing of seed germination. Subsequent divergence in the minimum critical temperature for germination has been detected between northeastern and eastern populations. An integrative analysis was conducted using combinations of phenotypic, genomic and transcriptomic data to investigate the genetic mechanism underlying local adaptation and feralization. A dozen genes were identified, which showed extreme allele frequency differences between eastern and northeastern populations, and high correlations between allele-specific gene expression and feral phenotypes. Trancing the origin of potential adaptive alleles based on genomic sequences revealed the presence of most selected alleles in wild and cultivated rice genomes, indicating that weedy rice drew upon pre-existing, “conditionally neutral” alleles to respond to the feral selection regimes. The cryptic phenotype was exposed by activating formerly silent alleles to facilitate the transition from cultivation to wild existence, promoting the evolution and persistence of weedy forms

    Multi-omics analysis reveals the prognostic and tumor micro-environmental value of lumican in multiple cancer types

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    Background: Lumican (LUM), a proteoglycan of the extracellular matrix, has been reported to be involved in the regulation of immune escape processes, but the data supporting this phenomenon are not sufficient. In this study, we aimed to explore the links among LUM expression, survival, tumor microenvironment (TME), and immunotherapy in 33 cancer types.Methods: Data from several databases, such as UCSC Xena, GTEx, UALCAN, HPA, GEPIA2, TISIDB, PrognoScan, TIMER2, and GEO, as well as published studies, were used to determine the relationship between LUM expression and clinical features, TME, heterogeneity, and tumor stemness.Results: The expression of LUM was statistically different in most tumors versus normal tissues, both at the RNA and protein expression levels. High expression of LUM was typically associated with a poor prognosis in tumors. Additionally, immune scores, six immune cells, four immunosuppressive cells, cancer-associated fibroblasts (CAFs)-associated and immunosuppressive factors, tumor mutation burden (TMB), microsatellite instability (MSI), DNAss, and RNAss were all significantly associated with LUM. Among them, LUM expression displayed a significant positive correlation with CAFs and their factors, and exhibited immunosuppressive effects in six independent immunotherapy cohorts.Conclusion: Multi-omics analysis suggests that LUM may have been a prognostic marker, contributed to immunosuppression in the TME, and decreased the effectiveness of immune checkpoint inhibitors

    Epidemiological investigation, determination of related factors, and spatial-temporal cluster analysis of wild type pseudorabies virus seroprevalence in China during 2022

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    IntroductionPseudorabies virus (PRV) is a linear DNA virus with a double-stranded structure, capable of infecting a diverse array of animal species, including humans. This study sought to ascertain the seroprevalence of Pseudorabies Virus (PRV) in China by conducting a comprehensive collection of blood samples from 16 provinces over the course of 2022.MethodsThe presence of PRV gE antibodies was detected through the utilization of an enzyme-linked immunosorbent assay (ELISA) technique. Logistic regression analysis was conducted to identify potential related factors associated with the serologic status of PRV gE at the animal level. Additionally, the SaTScan 10.1 software was used to analyze the spatial and temporal clusters of PRV gE seroprevalence.ResultsA comprehensive collection of 161,880 samples was conducted, encompassing 556 swine farms throughout the country. The analysis revealed that the seroprevalence of PRV gE antibodies was 12.36% (95% confidence interval [CI], 12.20% to 12.52%) at the individual animal level. However, at the swine farm level, the seroprevalence was considerably higher, reaching 46.22% (95% CI, 42.08% to 50.37%). Related factors for PRV infection at the farm level included the geographic distribution of farms and seasonal variables. Moreover, five distinct high seroprevalence clusters of PRV gE were identified across China, with the peak prevalence observed during the months of April through June 2022.ConclusionOur findings serve as a valuable addition to existing research on the seroprevalence, related factors, and temporal clustering of PRV gE in China. Furthermore, our study provides a reference point for the development of effective strategies for the prevention and control of pseudorabies and wild virus outbreaks
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