53 research outputs found

    Growth, Nutrient Uptake, and Foliar Gas Exchange in Pepper Cultured with Un-composted Fresh Spent Mushroom Residue

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    Spent mushroom substrate (SMS) can be used as the component of growing medium for the culture of crop plants. Fresh SMS may have the potential as an alternative to peat to raise horticultural plants. In this study, five container media characterized by the proportions of SMS to commercial peat in 0% (control), 25%, 50%, 75%, and 100% were used to raise pepper (Capsicum annum L.) plants. Initial SMS was found to have low available nitrogen (N) content (<20 mg kg-1) but moderate extractable phosphorus (P) content (900 mg kg-1). In the second month photosynthetic rate was found to decline in the 75% treatment. At harvest in the third month, plants in the 100% treatment nearly died out. The 25% treatment resulted in the highest height (19 cm) and diameter growth (0.3 cm), shoot (0.6 g) and root biomass accumulation (0.13 g), fruit weight (3 g), and shoot carbohydrate content (98 mg g-1), but lowest foliar acid phosphatase activity (30 µg NPP g-1 FW min-1). With the increase of SMS proportion in the substrate, the medium pH and electrical conductance (EC) increased with the decrease of foliar size. The available N and P contents in the substrates showed contrasting relationship with N and P contents in pepper plants. Therefore, fresh SMS cannot be directly used as the substrate for the culture of pepper plants. According to our findings fresh SMS was recommended to be mixed in the proportion of 25% with commercial peat for the culture of horticultural plants

    Four novel variants identified in primary hyperoxaluria and genotypic and phenotypic analysis in 21 Chinese patients

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    Background: Primary hyperoxaluria (PH) is a rare genetic disorder characterized by excessive accumulation of oxalate in plasma and urine, resulting in various phenotypes due to allelic and clinical heterogeneity. This study aimed to analyze the genotype of 21 Chinese patients with primary hyperoxaluria (PH) and explore their correlations between genotype and phenotype.Methods: Combined with clinical phenotypic and genetic analysis, we identified 21 PH patients from highly suspected Chinese patients. The clinical, biochemical, and genetic data of the 21 patients were subsequently reviewed.Results: We reported 21 cases of PH in China, including 12 cases of PH1, 3 cases of PH2 and 6 cases of PH3, and identified 2 novel variants (c.632T > G and c.823_824del) in AGXT gene and 2 novel variants (c.258_272del and c.866-34_866-8del) in GRHPR gene, respectively. A possible PH3 hotspot variant c.769T > G was identified for the first time. In addition, patients with PH1 showed higher levels of creatinine and lower eGFR than those with PH2 and PH3. In PH1, patients with severe variants in both alleles had significantly higher creatinine and lower eGFR than other patients. Delayed diagnosis still existed in some late-onset patients. Of all cases, 6 had reached to end-stage kidney disease (ESKD) at diagnosis with systemic oxalosis. Five patients were on dialysis and three had undergone kidney or liver transplants. Notably, four patients showed a favorable therapeutic response to vitamin B6, and c.823_824dup and c.145A > C may be identified as potentially vitamin B6-sensitive genotypes.Conclusion: In brief, our study identified 4 novel variants and extended the variant spectrum of PH in the Chinese population. The clinical phenotype was characterized by large heterogeneity, which may be determined by genotype and a variety of other factors. We first reported two variants that may be sensitive to vitamin B6 therapy in Chinese population, providing valuable references for clinical treatment. In addition, early screening and prognosis of PH should be given more attention. We propose to establish a large-scale registration system for rare genetic diseases in China and call for more attention on rare kidney genetic diseases

    Endogenous relapse and exogenous reinfection in recurrent pulmonary tuberculosis: A retrospective study revealed by whole genome sequencing

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    BackgroundTuberculosis may reoccur due to reinfection or relapse after initially successful treatment. Distinguishing the cause of TB recurrence is crucial to guide TB control and treatment. This study aimed to investigate the source of TB recurrence and risk factors related to relapse in Hunan province, a high TB burden region in southern China.MethodsA population-based retrospective study was conducted on all culture-positive TB cases in Hunan province, China from 2013 to 2020. Phenotypic drug susceptibility testing and whole-genome sequencing were used to detect drug resistance and distinguish between relapse and reinfection. Pearson chi-square test and Fisher exact test were applied to compare differences in categorical variables between relapse and reinfection. The Kaplan–Meier curve was generated in R studio (4.0.4) to describe and compare the time to recurrence between different groups. p < 0.05 was considered statistically significant.ResultsOf 36 recurrent events, 27 (75.0%, 27/36) paired isolates were caused by relapse, and reinfection accounted for 25.0% (9/36) of recurrent cases. No significant difference in characteristics was observed between relapse and reinfection (all p > 0.05). In addition, TB relapse occurs earlier in patients of Tu ethnicity compared to patients of Han ethnicity (p < 0.0001), whereas no significant differences in the time interval to relapse were noted in other groups. Moreover, 83.3% (30/36) of TB recurrence occurred within 3 years. Overall, these recurrent TB isolates were predominantly pan-susceptible strains (71.0%, 49/69), followed by DR-TB (17.4%, 12/69) and MDR-TB (11.6%, 8/69), with mutations mainly in codon 450 of the rpoB gene and codon 315 of the katG gene. 11.1% (3/27) of relapse cases had acquired new resistance during treatment, with fluoroquinolone resistance occurring most frequently (7.4%, 2/27), both with mutations in codon 94 of gyrA.ConclusionEndogenous relapse is the main mechanism leading to TB recurrences in Hunan province. Given that TB recurrences can occur more than 4 years after treatment completion, it is necessary to extend the post-treatment follow-up period to achieve better management of TB patients. Moreover, the relatively high frequency of fluoroquinolone resistance in the second episode of relapse suggests that fluoroquinolones should be used with caution when treating TB cases with relapse, preferably guided by DST results

    Effects of supplemental octanoate on hepatic lipid metabolism, serum biochemical indexes, antioxidant capacity and inflammation-related genes expression of large yellow croaker (Larimichthys crocea) fed with high soybean oil diet

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    Dietary high soybean oil (SO) levels might cause hepatic lipid deposition, induce oxidative stress and inflammatory response in aquatic animals, while octanoate (OCT) is beneficial to metabolism and health in mammals. However, the effect of OCT has been studied rarely in aquatic animals. In this study, a 10-week feeding trial was conducted to investigate the effect of supplemental OCT on hepatic lipid metabolism, serum biochemical indexes, antioxidant capacity and inflammatory response of large yellow croaker (Larimichthys crocea) fed with high SO levels diet. The negative control diet contained 7% fish oil (FO), while the positive control diet contained 7% SO. The other four experimental diets were supplemented with 0.7, 2.1, 6.3 and 18.9 g/kg sodium octanoate (OCT) based on the positive control diet. Results showed that OCT supplementation effectively reduced the hepatic crude lipid, triglyceride (TG), total cholesterol (TC) and non-esterified free fatty acids contents, and alleviated lipid accumulation caused by the SO diet. Meanwhile, OCT supplementation decreased the serum TG, TC, alanine transaminase, aspartate transaminase and low-density lipoprotein cholesterol levels, increased the serum high-density lipoprotein cholesterol level, improved the serum lipid profiles and alleviated hepatic injury. Furthermore, with the supplementation of OCT, the mRNA expression of genes related to lipogenesis (acc1, scd1, fas, srebp1, dgat1 and cebpα) and fatty acid (FA) transport (fabp3, fatp and cd36) were down-regulated, while the mRNA expression of genes related to lipolysis (atgl, hsl and lpl) and FA β-oxidation (cpt1 and mcad) were up-regulated. Besides that, dietary OCT increased the total antioxidant capacity, activities of peroxidase, catalase and superoxide dismutase and the content of reduced glutathione, decreased the content of 8-hydroxy-deoxyguanosine and malondialdehyde and relieved hepatic oxidative stress. Supplementation of 0.7 and 2.1 g/kg OCT down-regulated the mRNA expression of genes related to pro-inflammatory cytokines (tnfα, il1β and ifnγ), and suppressed hepatic inflammatory response. In conclusion, supplementation with 0.7-2.1 g/kg OCT could reduce hepatic lipid accumulation, relieve oxidative stress and regulate inflammatory response in large yellow croaker fed the diet with high SO levels, providing a new way to alleviate the hepatic fat deposition in aquatic animals

    The 2021 WHO catalogue of Mycobacterium tuberculosis complex mutations associated with drug resistance: a genotypic analysis.

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    Background: Molecular diagnostics are considered the most promising route to achievement of rapid, universal drug susceptibility testing for Mycobacterium tuberculosis complex (MTBC). We aimed to generate a WHO-endorsed catalogue of mutations to serve as a global standard for interpreting molecular information for drug resistance prediction. Methods: In this systematic analysis, we used a candidate gene approach to identify mutations associated with resistance or consistent with susceptibility for 13 WHO-endorsed antituberculosis drugs. We collected existing worldwide MTBC whole-genome sequencing data and phenotypic data from academic groups and consortia, reference laboratories, public health organisations, and published literature. We categorised phenotypes as follows: methods and critical concentrations currently endorsed by WHO (category 1); critical concentrations previously endorsed by WHO for those methods (category 2); methods or critical concentrations not currently endorsed by WHO (category 3). For each mutation, we used a contingency table of binary phenotypes and presence or absence of the mutation to compute positive predictive value, and we used Fisher's exact tests to generate odds ratios and Benjamini-Hochberg corrected p values. Mutations were graded as associated with resistance if present in at least five isolates, if the odds ratio was more than 1 with a statistically significant corrected p value, and if the lower bound of the 95% CI on the positive predictive value for phenotypic resistance was greater than 25%. A series of expert rules were applied for final confidence grading of each mutation. Findings: We analysed 41 137 MTBC isolates with phenotypic and whole-genome sequencing data from 45 countries. 38 215 MTBC isolates passed quality control steps and were included in the final analysis. 15 667 associations were computed for 13 211 unique mutations linked to one or more drugs. 1149 (7·3%) of 15 667 mutations were classified as associated with phenotypic resistance and 107 (0·7%) were deemed consistent with susceptibility. For rifampicin, isoniazid, ethambutol, fluoroquinolones, and streptomycin, the mutations' pooled sensitivity was more than 80%. Specificity was over 95% for all drugs except ethionamide (91·4%), moxifloxacin (91·6%) and ethambutol (93·3%). Only two resistance mutations were identified for bedaquiline, delamanid, clofazimine, and linezolid as prevalence of phenotypic resistance was low for these drugs. Interpretation: We present the first WHO-endorsed catalogue of molecular targets for MTBC drug susceptibility testing, which is intended to provide a global standard for resistance interpretation. The existence of this catalogue should encourage the implementation of molecular diagnostics by national tuberculosis programmes. Funding: Unitaid, Wellcome Trust, UK Medical Research Council, and Bill and Melinda Gates Foundation

    Research on Intelligent Design of Geometric Factor Encoding for Aircraft Engine Turbine Structures

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    In recent years, with the rapid development of computer technology and artificial intelligence design technology, multiple possible design solutions can be quickly generated by transforming the experience and knowledge of structural design into computer executable rules and algorithms. To achieve intelligent design of aircraft engines, this paper proposes an encoding model for the turbine rotor structure of aircraft engines using geometric encoding technology. The turbine rotor structure of aircraft engines is divided into several units according to geometric similarity types, these units continue to be divided into attribute sets according to their functional types, connection relationships, and material properties. These attribute sets can be encoded using geometric encoding technology. The experiment simulated that these codes, for the point cloud modeling of turbine rotor structure, can be quickly achieved and they combine various algorithms to display the point cloud model of the turbine rotor in the Microsoft Visual studio MFC class library. The results show that by creating geometric codes for the turbine rotor of aircraft engines, it is possible to quickly create and display point cloud models of the turbine rotor structure, laying the foundation for subsequent application of machine learning to solve and find the optimal design solution

    Eutectoid Transformation Kinetics of FeO under N2 and Air Atmospheres

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    The effect of different oxygen content on eutectoid transformation kinetics in FeO were studied in this paper. Thermogravimetric analysis was employed to investigate the eutectoid reaction in the oxide formed on pure Fe after being exposed to air at 900 °C for 10 min. The oxidized specimens were held isothermally in N2 and air from 100 s to 10,000 s in the temperature range of 350 to 550 °C, and the morphologies in FeO were observed by electron probe microanalysis. The results of the eutectoid transformation are statistically analyzed, and the dynamic model of the FeO eutectoid transformation is established based on the Johnson-Mehl-Avrami-Kolmogorov equation. Combined with the measured values and the calculation results, the time of eutectoid reaction in air is earlier than that in N2. Under the experimental conditions, the formation of Fe3O4 seams can occur at the interface of the FeO-substrate after the eutectoid reaction has begun, which means the eutectoid reaction is more determined by local ion concentration changes. At the Fe3O4-FeO interface, there is a high concentration enrichment of Fe ions, giving priority to the formation of Fe-rich FeO, which makes the eutectoid phase transition time earlier than in N2 conditions

    Synthesis of g-C<sub>3</sub>N<sub>4</sub> Derived from Different Precursors for Photodegradation of Sulfamethazine under Visible Light

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    In this study, a series of g-C3N4 nanosheets were prepared by various thermal oxidative etching times from four different precursors (urea, melamine, dicyandiamide and thiourea). The physicochemical properties of these g-C3N4 nanosheets were analyzed in detail using scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence emission spectra, Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis and ultraviolet-visible diffuse reflectance. The results revealed that the g-C3N4 nanosheets obtained a thinner layer thickness and larger specific surface area, with an extension of thermal oxidative etching time. Meanwhile, sulfamethazine (SMZ), one of the most widely used sulfonamides, was used to evaluate the photocatalyst activity of the g-C3N4 nanosheets prepared in this study. Compared to other g-C3N4 nanosheets, urea-derived g-C3N4 nanosheets under 330 min thermal oxidative etching showed the highest photocatalytic activity for SMZ under visible light. In conclusion, our study provides detailed insights into the synthesis and characterization of g-C3N4 nanosheets prepared from various precursors and highlights the importance of thermal oxidative etching time in determining the photocatalytic activity of these materials

    Identification and drug susceptibility testing of the subspecies of Mycobacterium avium complex clinical isolates in mainland China

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    Objectives: The Mycobacterium avium complex (MAC), comprising a series of subspecies, has a worldwide distribution, with differences in drug susceptibility among subspecies. This study aimed to assess the composition of MAC and susceptibility differences among subspecies in mainland China. Methods: A total of 287 MAC clinical strains were included in the study. Multitarget sequences were applied to accurately identify subspecies, and a microdilution method was used to evaluate minimum inhibitory concentrations (MICs) among subspecies using Sensititre SLOMYCO plates. Results: Mycobacterium intracellular (N = 169), Mycobacterium avium (N = 52), Mycobacterium chimaera (N = 22), Mycobacterium marseillense (N = 25), Mycobacterium colombiense (N = 14), Mycobacterium yongonense (N = 4), Mycobacterium vulneris (N = 3) and Mycobacterium timonense (N = 2) were isolated from MAC. Clarithromycin, amikacin and rifabutin showed lower MIC50 and MIC90 values than other drugs, and the resistance rates of clarithromycin, amikacin, linezolid and moxifloxacin were 6.3%, 10.5%, 51.9% and 46.3%, respectively. The resistance rates of clarithromycin and moxifloxacin in the initial treatment group were significantly lower than those in the retreatment group (4.09% vs. 12.94%; 30.41% vs. 75.29%; P < 0.05). Drug susceptibility differences were observed in clarithromycin and moxifloxacin among the five major subspecies (P < 0.05); however, those statistically significant differences disappeared when MACs were divided into two groups according to previous anti-tuberculosis (anti-TB) treatment history. Conclusion: This study revealed that MAC, primarily comprising M. intracellulare, was susceptible to clarithromycin, amikacin and rifabutin. Drug susceptibility among subspecies did not exhibit intrinsic differences in our study. Previous anti-TB treatment patients are more resistant to drugs; thus, attention should be given to those patients in the clinic
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