227 research outputs found

    Infinite families of MDS and almost MDS codes from BCH codes

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    In this paper, the sufficient and necessary condition for the minimum distance of the BCH codes over Fq\mathbb{F}_q with length q+1q+1 and designed distance 3 to be 3 and 4 are provided. Let dd be the minimum distance of the BCH code C(q,q+1,3,h)\mathcal{C}_{(q,q+1,3,h)}. We prove that (1) for any qq, d=3d=3 if and only if gcd(2h+1,q+1)>1\gcd(2h+1,q+1)>1; (2) for qq odd, d=4d=4 if and only if gcd(2h+1,q+1)=1\gcd(2h+1,q+1)=1. By combining these conditions with the dimensions of these codes, the parameters of this BCH code are determined completely when qq is odd. Moreover, several infinite families of MDS and almost MDS (AMDS) codes are shown. Furthermore, the sufficient conditions for these AMDS codes to be distance-optimal and dimension-optimal locally repairable codes are presented. Based on these conditions, several examples are also given

    Nickel-based superalloy architectures with surface mechanical attrition treatment:Compressive properties and collapse behaviour

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    Surface modifications can introduce natural gradients or structural hierarchy into human-made microlattices, making them simultaneously strong and tough. Herein, we describe our investigations of the mechanical properties and the underlying mechanisms of additively manufactured nickel–chromium superalloy (IN625) microlattices after surface mechanical attrition treatment (SMAT). Our results demonstrated that SMAT increased the yielding strength of these microlattices by more than 64.71% and also triggered a transition in their mechanical behaviour. Two primary failure modes were distinguished: weak global deformation, and layer-by-layer collapse, with the latter enhanced by SMAT. The significantly improved mechanical performance was attributable to the ultrafine and hard graded-nanograin layer induced by SMAT, which effectively leveraged the material and structural effects. These results were further validated by finite element analysis. This work provides insight into collapse behaviour and should facilitate the design of ultralight yet buckling-resistant cellular materials.</p

    Assessing the effects of different management activities on the conservation of endangered Indo-Pacific humpback dolphin

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    Predictions of population viability can provide valid information for guiding the management and conservation of species. However, such studies are rarely conducted on cetaceans due to limited basic data. In this study, a detailed assessment of the population dynamics of Indo-Pacific humpback dolphins (Sousa chinensis) in Xiamen Bay, China was carried out using a Vortex model that was based on model parameters that were derived from monitoring data and published sources. Then, sensitivity analyses were conducted to test the relative importance of the uncertainty of the model parameters. Moreover, potential management models were evaluated to determine their effectiveness in assisting with species recovery. The baseline model projected a decline in the population abundance with a growth rate (r) of -0.031, and the probability of extinction was 58.7% over the next 100 years. The sensitivity analyses revealed that juvenile mortality and fertility were the most pivotal factors for the viability of this population. All the conservation measures, including habitat improvement, catastrophe control, and individual supplementation, contributed to population increases when compared with the baseline model. In particular, decreasing calf and juvenile mortality through habitat improvement, at high levels, was the only way to generate positive growth rates. The findings suggest that these practical management activities can reduce the risk of extinction for this species

    Urinary and Serum Metabolomics Analyses Uncover That Total Glucosides of Paeony Protect Liver against Acute Injury Potentially via Reprogramming of Multiple Metabolic Pathways

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    Total glucosides of paeony (TGP) have been confirmed to be hepatoprotective. However, the underlying mechanism is largely unclear. In this study, we investigated the metabolic profiles of urine and serum in rats with carbon tetrachloride- (CCl4-) induced experimental liver injury and TGP administration by using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The vehicle or a single dose of TGP was intragastrically administered to Wistar rats once a day for 14 consecutive days. To induce ALI, 50% CCl4 was injected intraperitoneally into these rats 2 hours after the last time administration of saline of TGP at the 14th day. The results indicated that TGP administration could protect rats from CCl4-induced ALI and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevation, as well as hepatocyte apoptosis and inflammation. Furthermore, metabolomics analysis showed that TGP treatment significantly attenuated CCl4-triggered deregulation of multiple metabolites in both urine and serum, including glycine, alanine, proline, and glutamine. Metabolite set enrichment and pathway analyses demonstrated that amino acid cycling and glutathione metabolism were two main pathways involved in CCl4-induced experimental liver injury and TGP administration. Taken together, these findings revealed that regulation of metabolites potentially plays a pivotal role in the protective effect of TGP on ALI

    The Virulence-Related MYR1 Protein of Toxoplasma gondii as a Novel DNA Vaccine Against Toxoplasmosis in Mice

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    Toxoplasma gondii causes serious public health problems, but there is no effective treatment strategy against it currently. DNA vaccines have shown promising findings in this regard. MYR1 is a new virulence factor identified in T. gondii that may have potential as a DNA vaccine candidate. We constructed a recombinant eukaryotic plasmid, pVAX1-MYR1, as a DNA vaccine, injected it intramuscularly into BALB/c mice, and evaluated its immunoprotective effects. pVAX1-MYR1 immunization induced a sequential Th1 and Th2 T-cell response, as indicated by high levels of Th1 and mixed Th1/Th2 cytokines at 2 and 6 weeks after immunization, respectively. These findings were corroborated by the antibody assays too. In addition, increased levels of antigen-specific lymphocyte proliferation, CD4+ and CD8+ T lymphocytes, cytotoxic T lymphocyte activity and cytokine (IFN-γ, IL-12, and IL-10) production were also observed in the immunized mice. These findings showed that pVAX1-MYR1 stimulated humoral and cellular immune responses in the immunized mice. The increased production of IFN-γ and IL-12 was correlated with increased expression of the T-bet and p65 genes of the NF-κB pathway. However, no significant increase was observed in the level of IL-4. The survival of mice immunized with pVAX1-MYR1 was also significantly prolonged compared with the control group mice. Based on all the above findings, the current study proposes that pVAX1-MYR1 can induce a T. gondii-specific immune response and should therefore be considered as a promising vaccine candidate against toxoplasmosis. To the best of our knowledge, this is the first report to evaluate the immunoprotective value of an MYR1-based DNA vaccine against T. gondii
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