Optimization of fertilization scheme based on sustainable wheat productivity and minor nitrate residue in organic dry farming: An empirical study.

The substitution of chemical nitrogen fertilizer with manure holds the potential for a synergistic rise in wheat grain yield and protein concentration, while minimizing residual nitrate in soil. We conducted a 6-year field fertilization experiment including two manure treatments (with or without) and five nitrogen applications rates (0, 60, 120, 180 and 240 kg ha-1). The study investigated the impact of single chemical nitrogen (CN) and manure substitution for nitrogen fertilizer (MN) on the grain yield (GY), grain protein concentration (GPC), plant nitrogen uptake (PNupt) and plant nitrogen requirement (PNR) of wheat, and the dynamic change of soil nitrate-N. The findings revealed that: (1) the MN demonstrated a greater advantage over CN, as evidenced by a 13.4-16.0 % increase in GY, a 2.6-3.8 % increase in GPC, a 7.2-15.7 % increase in PNupt and a 1.5-4.7 % reduction in PNR. (2) Soil nitrate accumulation (SNA) significantly increased when fertilizer rates ≥180 kg ha-1 and the peak annually shifted to deeper layer. The MN increased the SNA0-100 by 20.9-21.8 %, but significantly reduced SNA0-200 by 11.8-13.5 % compared with the CN. Topsoil nitrate content (SNC0-20) can be adopted as a substitute for SNA0-100 to make the fertilization schedule convenient. (3) Regression analysis revealed (taking the MN for example) that the optimum N rates for the maximum GY (5417 kg ha-1) and GPC (15.3 %) were 164 and 211 kg N ha-1, respectively. The nitrate-N safety threshold was 62 kg ha-1 at the fertilizer rate of 89 kg N ha-1. Based on this, nitrogen fertilizer input reduced by 44.8-57.2 % and SNA0-200 by 17.9-33.6 %, with achieving 91.8-95.0 % of maximum GY and 89.7-92.9 % of maximum GPC. Substituting manure for nitrogen fertilizer achieved the potential of maintaining the grain yield and protein concentration while the minimization in soil nitrate residue. This study offers a feasible way for fertilization recommendation and nitrate residue controlling in dry farming.

Genomic epidemiology reveals early transmission of SARS-CoV-2 and mutational dynamics in Nanning, China.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are a fatal pathogen resulting in substantial morbidity and mortality, and posing a great threat to human health with epidemics and pandemics. METHODS: Next-generation sequencing (NGS) was performed to investigate the SARS-CoV-2 genomic characterization. Phylogenetic analysis of SARS-CoV-2 genomes was used to probe the evolutionary. Homology protein structure modelling was done to explore potential effect of the mutations. RESULTS: The eighty genome sequences of SARS-CoV-2 obtained from the thirty-nine patients with COVID-19. A novel variant with mutation H625R concomitant with S50L in spike glycoprotein had been identified. Phylogenetic analysis revealed that SARS-CoV-2 variants belong to several distinct lineages. Homology modelling indicated that variant with mutation H625R and S50L increases flexibility of S1 subunit. CONCLUSIONS: SARS-CoV-2 genomes are constantly evolving by accumulation of point mutations. The amino acid H625R in combination with S50L may have a significant impact on the interaction between spike glycoprotein and ACE2.

Effects of elevated atmospheric ammonia concentration on photosynthetic characteristics and grain yield in wheat under different nitrogen rates.

To evaluate the effects of nitrogen (N) application rates on the growth, photosynthetic traits and yield of winter wheat under elevated atmospheric ammonia (NH3) concentrations could provide guidance for N management under high NH3 environment. We conducted a split-plot experiment for two consecutive years (2020-2021 and 2021-2022) with top-open chambers. The treatments included two NH3 concentrations [elevated ambient NH3 concentration at 0.30-0.60 mg·m-3 (EAM) and air NH3 concentration at 0.01-0.03 mg·m-3 (AM)] and two N application rates [recommended N dose (+N) and no N application (-N)]. We analyzed the effects of aforementioned treatments on net photosynthetic rate (Pn), stomatal conductance (gs), chlorophyll content (SPAD value), plant height, and grain yield. The results showed that averaged across the two years, EAM significantly increased Pn, gs, and SPAD values at the jointing and booting stages at the -N level by 24.6%, 16.3%, 21.9% and 20.9%, 37.1%, 5.7%, respectively, compared with AM. However, EAM significantly decreased Pn, gs, and SPAD values at jointing and booting stages at +N level by 10.8%, 5.9%, 3.6% and 6.8%, 18.9%, 9.3%, respectively, over AM treatment. There was a significant effect of NH3 treatment, N application rates and their interaction on plant height and grain yield. Compared with AM, EAM increased the average plant height and grain yield by 4.5% and 32.1% at -N level and decreased by 1.1% and 8.5% at +N level, respectively. In a nutshell, the eleva-ted ambient NH3 concentration had positive effect on photosynthetic characteristics, plant height, and grain yield under ambient N condition, but a inhibitory effect under N application.

Viral Dynamic Surveillance in COVID-19 Patients: A Cohort Study.

Background: Coronavirus disease 2019 (COVID-19) is a potentially fatal pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially those of novel SARS-CoV-2 variants and infection has affected over 700 million people globally. Methods: This retrospective, descriptive study included 118 patients admitted with SARS-CoV-2 infection as confirmed by real-time reverse transcription polymerase chain reaction. Results: The median duration of detectable SARS-CoV-2 infection in patients with high ALT, AST, and PLT/LYMPH, or low CD4+, CD8+, and PLT/MONO was considerably longer. In the risk factor model, multivariate analysis was performed for the estimation of ALT (HR, 0.54; 95% CI, 0.36-0.81), AST (HR, 0.56; 95% CI, 0.34-0.93), CD4+ (HR,0.77; 95% CI, 0.48-1.24), CD8+ (HR,0.64; 95% CI, 0.37-1.11), PLT/LYMPH (HR, 1.16; 95% CI, 0.76-1.77), and PLT/MONO (HR, 0.64; 95% CI, 0.43-0.94). Conclusions: The longer viral RNA duration was associated with a higher International Prognostic Index score (p = 0.0013), demonstrating for the first time that multivariate features of the bioindicators closely associated with SARS-CoV-2-infected patients clear the virus.

Mycobacterium vaccae Nebulization in the Treatment of COVID-19: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Severe acute respiratory syndrome coronavirus 2 infection is associated with strong infectiousness and has no effective therapy. We aimed to explore the efficacy and safety of Mycobacterium vaccae nebulization in the treatment of Coronavirus Disease 2019 (COVID-19). Methods: In this randomized, double-blind, placebo-controlled clinical trial, we included 31 adult patients with moderate COVID-19 who were admitted to the Fourth People's Hospital of Nanning (Nanning, China) between January 22, 2020 and February 17, 2020. Patients were randomly divided into two groups: group A (standard care group) and group B (M. vaccae in combination with standard care group). The primary outcome was the time interval from admission to viral RNA negative conversion (oropharyngeal swabs were used in this study). Secondary outcomes included chest computed tomography (CT), mortality, length of hospital stay, complications during treatment, and so on. Patients were followed up to 4 weeks after discharge (reexamination of viral RNA, chest CT, etc.). Results: Nucleic acid test negative conversion time in group B was shorter than that in group A (2.9 days [2.7-8.7] vs. 6.8 days [3.3-13.8]; p = 0.045). No death and no conversion to severe or critical cases were observed in both groups. Two weeks after discharge, neither "relapse" nor "return to positive" cases were found. Four weeks after discharge, it was found that there was no case of " relapse " or "return to positive" in group B, and 1 patient in group A showed "return to positive", but there was no clinical manifestation and imaging progression. No adverse reactions related to M. vaccae were found during observation period. Conclusion:M. vaccae treatment might shorten the time interval from admission to viral RNA negative conversion, which might be beneficial to the prevention and treatment of COVID-19. Clinical Trial Registration: ChiCTR2000030016.

[Clinical study of artesunate in the treatment of coronavirus disease 2019].

OBJECTIVE: To discuss the effective of artesunate in the treatment of coronavirus disease 2019 (COVID-19). METHODS: Using prospective method, the 43 cases of confirmed COVID-19 patients in Nanning Fourth People's Hospital from January 22nd to February 15th in 2020 were enrolled and divided into routine treatment group (n = 25) and artesunate treatment group (n = 18) by odd-even rule after admission. According to the guidelines, the routine treatment group was recommended to receive lopinavir/ritonavir 500 mg + α-aerosolized interferon 500×104 U, twice daily; the artesunate treatment group was given artesunate 60 mg, twice daily besides the routine treatment, for 10 days in both groups. During the treatment period, the pharynx swab test of 2019 novel coronavirus (2019-nCoV) nucleic acid was carried out every 2 days, and the routine blood test, liver and kidney functions, blood coagulation function and myocardial enzymes were re-examined. Chest CT was checked every 3 days after the treatment, and re-examined every 5 days after the condition was improved. The routine blood test and biochemical results of two groups were observed, and the efficacy evaluation was performed by monitoring the time for significant improvement of symptoms, negative conversion time of throat swab virus nucleic acid, lung lesion absorption time, adverse drug reactions and the length of hospital stay of the two groups. RESULTS: There were no significant differences between the two groups in terms of gender, age, body weight, routine blood test and biochemical results before treatment. In artesunate treatment group, the time for significant improvement of symptoms (days: 3.33±1.91 vs. 4.84±2.19), negative conversion time of 2019-nCoV nucleic acid (days: 4.72±2.16 vs. 6.68±3.76), lung lesion absorption starting time (days: 5.39±2.36 vs. 7.48±3.78), lung lesion absorption greater than 70% time (days: 14.11±4.16 vs. 17.04±4.42) and the length of hospital stay (days: 16.56±3.71 vs. 18.04±3.97) were significantly shorter than those in routine treatment group, with significant differences (all P < 0.05). The incidence of adverse drug reactions in two groups had no significant difference (72.2% vs. 80.0%, P > 0.05). CONCLUSIONS: Artesunate can shorten the treatment time of COVID-19, improve prognosis and eliminate pathogens, with fewer adverse reactions and a good application prospect.

[Analysis of clinical characteristics of severe and critically ill influenza A (H1N1)].

OBJECTIVE: To investigate the clinical features, laboratory results, chest CT imaging manifestations and treatments of severe and critical influenza A (H1N1), and to analyze the relationship with the prognosis. METHODS: The clinical data of 54 adult patients with severe and critical H1N1 admitted to the Fourth People's Hospital of Nanning from November 2018 to February 2019 were analyzed retrospectively. Throat swab specimens of the patients were determined for nucleic acid detection of influenza A (H1N1) virus, and all of the patients were confirmed. The gender, age, course of disease, underlying diseases, symptoms, body temperature, hospital stays, chest CT findings and laboratory results were collected, and the treatments and prognosis were recorded. RESULTS: Of 54 patients, 38 patients were enrolled in severe group, and 16 in critical group. Fever, cough, sputum, shortness of breath and so on could be found in the two groups. The CD4+T lymphocytes were less than normal reference value (410-1 590/µL) in both groups. The chest CT findings manifestations of severe group were scattered patchy shadows and ground glass appearance, all of them were cured and discharged after antiviral, antibiotics, and oxygen treatment. In critical group, the time in hospital was longer, the disease progresses varied faster, the shortness of breath was more apparent, and a large patch of fuzzy and real change shadows on both lungs could be found from CT findings. Compared with the severe group, creatine kinase (CK), lactic dehydrogenase (LDH), C-reactive protein (CRP) and procalcitonin (PCT) levels in the critical group were increased more significantly [CK (U/L): 704.50 (908.50) vs. 146.00 (220.75), LDH (U/L): 614.50 (492.25) vs. 217.00 (142.75), CRP (mg/L): 85.65 (56.13) vs. 18.80 (50.63), PCT (µg/L): 1.30 (5.00) vs. 0.10 (0.16), all P < 0.01], white blood cells count (WBC) and neutrophil ratio were also increased more significantly [WBC (×109/L): 12.37±7.63 vs. 8.29±3.32, neutrophil ratio: 0.81±0.11 vs. 0.75±0.11] without statistical differences (both P > 0.05). Nine patients in critical group were cured with cure rate of 56.25%. Seven patients died with mortality of 43.75%, including 2 patients with acquired immunodeficiency syndrome (AIDS) and uremia respectively, who had multiple organ failure (MOF) on admission and waive the mechanical ventilation treatment; 3 patients complicated with acute renal failure but abandon hemodialysis; 1 patient with nasopharyngeal carcinoma radiotherapy after operation; and 1 patient with chronic renal failure uremia period combined multiple drug-resistant bacteria infection, and died from MOF finally. CONCLUSIONS: The patients with severe and critical influenza A (H1N1) show fever, cough, dyspnea, and organ dysfunction in varying degrees. Severe patients were mainly pulmonary lesions, while critical patients show MOF such as heart, lung and kidney, and the lesions progressed rapidly. The major cause of death for critical influenza A (H1N1) may be chronic underlying diseases and MOF.

Degradable Chitosan-Collagen Composites Seeded with Cells as Tissue Engineered Heart Valves.

BACKGROUND: Degradable collagen-chitosan composite materials have been used to fabricate tissue engineered heart valves. The aims of this study were to demonstrate that the collagen-chitosan composite scaffolds are cytocompatible, and endothelial cells can be differentiated from bone marrow mesenchymal stem cells (BMSCs) when seeded onto the scaffolds. The adhesion and biological activities of the seeded cells were also investigated. METHODS: Collagen-chitosan composite material was used as the cell matrix, and smooth muscle cells, fibroblasts and BMSCs were used as seed cells. After four weeks of in vitro culture, the smooth muscle cells, fibroblasts, and BMSCs were sequentially seeded into the collagen-chitosan composite material. After four weeks in culture, the cellular density and activity were assessed on segments of the tissue engineered heart valve scaffolds to determine the cell viability and proliferation in the collagen-chitosan composite material. RESULTS: The tissue engineered heart valves stained positively for both smooth muscle actin and endothelial cell factor VIII, suggesting that the seeded cells were in fact smooth muscle cells, fibroblasts, and endothelial cells. The 6-ketone prostaglandin content, as measured by radioimmunoassay, of the collagen-chitosan cell culture fluid was higher than that of the serum-free medium (P <0.01). Light and electron microscopy showed that the seeded cells had shapes similar to the morphology of smooth muscle cells, fibroblasts, and endothelial cells. CONCLUSIONS: Endothelial cells can be differentiated from BMSCs when seeded onto the collagen-chitosan composite scaffolds. The seeded cells retained their biological activity after being cultured in vitro and seeded into the collagen-chitosan composite material.