Applying nitrogen (N) fertilizer at irrational rates and basal topdressing ratios typically leads to high resource wastage and serious environmental pollution and is a global problem. A pot ...experiment was conducted between 2020 and 2021 to investigate the effects of different N application rates and basal topdressing ratios on the growth, yield, quality, and water- and N- use efficiencies of forage maize. Four N treatments were used, with the following levels: 0 kg/ha (N0), 70 kg/ha (N70), 140 kg/ha (N140), and 210 kg/ha (N210); and two basal topdressing ratios of N fertilizer were tested, namely: 2:8 and 4:6. An increased N application rate, from 0 to 200 kg/ha, increased whole fresh and dry yields. N fertilization increased the crude protein (CP) content of different plant parts (stems, leaves, and ears), as well as at the whole plant level, but decreased neutral and acid detergent fiber content. The dry matter water use efficiency (WUEDM) increased, while the partial-factor productivity of applied N decreased with an increasing N application rate. Compared with N0, the 2-year average dry matter yield under N70, N140, and N210 increased by 21.8%, 27.6%, and 38.2%, respectively, while WUEDM increased by 19.1%, 28.7%, and 45.0%, respectively. At the 2:8 basal topdressing ratio, the dry matter yield, CP content, and N recovery efficiency under all N application rates were higher at harvest compared to the 4:6 ratio during normal rainfall years, while dry matter yield and WUEDM were both lower compared to the 4:6 ratio during dry years. In conclusion, during a normal rainfall year, a N application rate of 210 kg/ha, with a basal topdressing ratio of 2:8 between the sowing and jointing stages, is considered the optimal N fertilizer application strategy to improve forage maize production in the semi-arid areas of the Chinese Loess Plateau.
Investigating the responses of forage crop yield, quality, and nitrogen (N) use efficiency to different N application rates is beneficial for guiding proper N fertilization regimes and for reducing ...reactive N environmental pollution. A field experiment was conducted to investigate the effects of different N application rates on above-ground dry matter yield, forage quality, crop N uptake, N use efficiency (NUE), and ecosystem economic benefits (EEBs) of forage sorghum cultivated on the Longdong Loess Plateau in 2019 and 2020. Five N application rates were tested, namely 0, 80, 160, 240, and 320 kg·ha−1 (referred to as N0, N80, N160, N240, and N320, respectively). The maximum above-ground dry matter yield (22.3 t·ha−1 in 2019 and 18.0 t·ha−1 in 2020) was obtained at an N application of 160 kg·ha−1. Forage sorghum crude protein (CP) content increased significantly with increasing N application rates (the CP content at N320 was 7.4% and 8.6% in 2019 and 2020, respectively). In contrast, neutral detergent fiber (NDF) and acid detergent fiber (ADF) were only affected by high N application rates (NDF and ADF were significantly higher in N320 compared with N0 and N90). The relative feed value (RFV) was significantly higher in N0 compared with N320. Crop N uptake was significantly higher in N160 compared with N0 (25.7% increase to 249.4 kg·ha−1 in 2019 and 40.5% increase to 247.4 kg·ha−1 in 2020, respectively). NUE decreased linearly as N rates increased, but NO3−–N residue (0–200 cm), reactive N loss (Nr loss), and greenhouse gas (GHG) emissions increased. Private profitability and EEB were the largest at N160 (private profitability at N160 was 514.2 USD·ha−1, and EEB at N160 was 392.7 USD·ha−1). Above-ground yield and optimum forage quality must be maximized, while simultaneously safeguarding farmer income and reducing environmental pollution from N fertilizers. Therefore, the optimum N application rate for forage sorghum cultivation in the dry areas of the Loess Plateau is recommended at 160 kg·ha−1.
Osteosarcoma (OS) is the most common pediatric bone malignancy worldwide. The MDM2 gene is an important candidate gene for influencing the susceptibility to OS. The objective of this study aimed to ...detect the potential association between MDM2 genetic variants and OS susceptibility in Chinese Han population. We recruited 415 OS patients and 431 cancer-free controls in this case-control study. The c.44C>T and c.1002T>C genetic variants in MDM2 gene were investigated using created restriction site-polymerase chain reaction (CRS-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), respectively. We found that the genotypes/alleles of c.44C>T and c.1002T>C were statistically associated with the increased risk of OS (for c.44C>T, TT versus (vs.) CC: OR = 2.43, 95% CI 1.49-3.95, p < 0.001; T vs. C: OR = 1.36, 95% CI 1.11-1.67, p = 0.003; for c.1002T>C, CC vs. TT: OR = 2.38, 95% CI 1.37-4.13, p = 0.002; C vs. T: OR = 1.27, 95% CI 1.02-1.56, p = 0.030). The T allele and TT genotype of c.44C>T and C allele and CC genotype of c.1002T>C could be increased risk factors for the susceptibility to OS. Results from this study suggest that MDM2 genetic variants are potentially related to OS susceptibility in Chinese Han population, and might be used as molecular markers for assessing OS susceptibility.
Mesenchymal stem cells (MSCs) have been highlighted as promising candidate cells in relation to cutaneous wound healing. The current study aimed to investigate whether MSC‐derived extracellular ...vesicles (EVs) could transfer microRNA‐27b (miR‐27b) to influence cutaneous wound healing. The miR‐27b expression was examined in the established cutaneous wound mouse model, and its correlation with the wound healing rate was evaluated by Pearson's correlation analysis. The identified human umbilical cord MSC‐derived EVs were co‐cultured with human immortal keratinocyte line HaCaT and human skin fibroblasts (HSFs). The mice with cutaneous wound received injections of MSC‐derived EVs. The effects of EVs or miR‐27b loaded on wound healing and cellular functions were analysed via gain‐ and loss‐of‐function approaches in the co‐culture system. Dual‐luciferase reporter gene assay was employed to verify the relationship between miR‐27b and Itchy E3 ubiquitin protein ligase (ITCH). Rescue experiments were conducted to investigate the underlying mechanisms associated with the ITCH/JUNB/inositol‐requiring enzyme 1α (IRE1α) axis. miR‐27b was down‐regulated in the mouse model, with its expression found to be positively correlated with the wound healing rate. Abundant miR‐27b was detected in the MSC‐derived EVs, while EV‐transferred miR‐27b improved cutaneous wound healing in mice and improved proliferation and migration of HaCaT cells and HSFs in vitro. As a target of miR‐27b, ITCH was found to repress cell proliferation and migration. ITCH enhanced the JUNB ubiquitination and degradation, ultimately inhibiting JUNB and IRE1α expressions and restraining wound healing. Collectively, MSC‐derived EVs transferring miR‐27b can promote cutaneous wound healing via ITCH/JUNB/IRE1α signalling, providing insight with clinical implications.
Food equivalent unit (FEU) is a vector used to measure the value of food based on its calorie and protein content and their digestibility. However, the optimal planting density and N application rate ...for maximizing the FEU yield (FEUY) of forage maize (Zea mays L.) is still poorly understood in the fast-growing animal husbandry regions of the Chinese Loess Plateau. Here, a 2-year consecutive field experiment was conducted to explore the impacts of planting density, N application rate, and their interactions on growth, dry matter yield (DMY), forage quality, and FEUY of a dominant forage maize cultivar. Planting density significantly affected the stem diameter, LAI, DMY, and dry matter allocation (DMA) of the leaf. Initially, increasing the N rate increased the stem diameter, LAI, FEUY, and DMY of forage maize and then decreased. The stem diameter, LAI, FEUY and above-ground DMY peaked under 180 kg∙ha−1 N in both years. Moreover, N application significantly increased the crude protein content of the whole plant and decreased the acid detergent fiber content. The surface fittings of the 2-year study indicated that 110,000 plants∙ha−1 (plant density) and 171.2 kg∙ha−1 (N rate) obtained the greatest DMY (19.0 t∙ha−1). The grade index (a comprehensive evaluation index for forage quality) peaked at 15.4 MJ∙d−1 under 94,000 plants ha−1 and 270 kg∙ha−1. The 110,000 plants∙ha−1 plant density and 181.5 kg∙ha−1 N rate jointly maximized the FEUY (11,125.4 FEU∙ha−1), maintaining 99.9 % of the maximum DMY and 97.5 % of the maximum grade index. Thus, 110,000 plants∙ha−1 plant density and 181.5 kg∙ha−1 N rate are recommended for high-productivity forage maize production, without notably compromising dry matter yield and feed quality. This research is conducive to advancing the coordinated development of forage crop cultivation and herbivorous livestock farming in semi-arid rainfed areas.
•The effect of N rates on grade index of forage maize is greater than that of planting density.•Density 110,000 plants∙ha−1 and N rate 181.5 kg∙ha−1 maximized food equivalent unit yield.•The optimal maintained 99.9 % of the yield and 97.5 % maximum grading index.
An extremely rare spontaneous pseudoaneurysm (PSA) of the posterior tibial artery (PTA) in a middle-aged male patient was cured by open surgery effectively.
A 53-year-old man presented with the ...increasing swollen left shank for 1 day, with intermittent pain, pulselessness and pallor. He denied the history of trauma, infection, and other diseases.
Physical examination, past medical history, ankle brachial index, ultrasonography, computed tomographic angiography (CTA), 3-dimensional reconstruction image of the popliteal artery and its branches and histological examination of intraluminal thrombus and clots helped us diagnose the patient as spontaneous PSA of PTA.
Our patient underwent excision of PSA and repair operation of PSA.
The patient recovered well at 2-year follow-up.
This rare case provides valuable insights for tissue repair and vascular surgery. Therapeutic methods should be in accordance with the best interest of patient. Open surgery is the effective treatment for spontaneous PSA of PTA.
Abstract A macro–micro–nano–multi-level study was conducted to explore age-related structural and mechanical properties of bone, as well as the effects of aging on bone properties. A total of 70 male ...Wistar rats were used, ranging in the ages of 1, 3, 5, 7, 9, 11, 14, 15, 16, and 17 months ( n = 7/age group). After micro-computed tomography (CT) scanning, longitudinal cortical bone specimens with a length of 5 mm were cut along the femoral shaft axis from left femur shafts for mechanical testing, and the cross-sectional areas were measured. The macro-mechanical properties obtained in mechanical testing and microarchitecture parameters measured by micro-CT were significantly correlated with the animal age (r2 = 0.96, p < 0.001). Scanning electron microscopy was used for detecting the microarchitecture features of the fractured surfaces, which exhibited age-related plate-fibrous-mixed fibrous-plate texture, resulting in changes in macro-mechanical properties (r2 > 0.90, p < 0.001). The mineral phase of the left femoral shaft and head was analyzed by atomic force microscopy. Longitudinal and transverse trabecular bone tissues, as well as longitudinal cortical bone tissue, were used for nanoindentation test, and the chemical composition was evaluated by quantitative chemical analyses. The correlations between mineral content and bone material properties (i.e., elastic properties of the bone tissue and size and roughness of bone mineral grains) were highly significant (r > 0.95, p < 0.001). Multi-level femur morphology, mechanical property, and mineral content were significantly correlated with the animal age. The correlations between bone mineral content and bone material morphological and mechanical properties may partly explain the increase in bone fragility with aging, which will provide a theoretical basis for the investigation of age-related bone properties in clinics.
Appropriate nitrogen (N) fertilizer application can improve crop yield, increase N-use efficiency and reduce environmental pollution. A two-year field experiment was performed to explore the ...influences of N fertilizer rates on dry matter yield, crop N removal, N-use efficiency and apparent N budget. Five N application rates, i.e. 0, 70, 140, 210 and 280 kg N ha
−1
(referred to as N0, N70, N140, N210 and N280) were tested. The application of fertilizer N markedly increased the dry matter yield of forage maize, which was highest for N210 with a two-year average of 22.6 t ha
−1
. The N210 treatment increased crop N removal by 34.9% on average compared with N0. As the N rate increased, soil nitrate-N accumulation increased exponentially, apparent N loss increased linearly and agronomic efficiency clearly decreased. The apparent N loss and soil nitrate-N accumulation decreased by 19.4% and 19.0%, respectively, and partial-factor productivity increased by 24.5% under the N rate that maximizes profit (195.1 kg ha
−1
) in comparison with those under the N rate that maximizes yield (244.4 kg ha
−1
). The N rate (195.1 kg ha
−1
) is recommended to maximize profit and minimize environmental costs in forage maize production in the semi-arid region in China.
The aim of this study was to investigate the influences of low-magnitude high-frequency vibration (LMHFV) with different rest period regimes (vibrational loading per day with or without the loading ...divided into bouts; or vibrational loading for 7 day followed by 7 day rest with or without the loading divided into bouts) on bone healing at multi-levels. Transverse fractures of rat bilateral tibias were established using a Kirschner wire inserted for fixation. The animals were randomly assigned to five groups (
n
= 7 for each group): four for vibrational groups by LMHFV with different rest period regimes and one for fractured model without mechanical loading. The macromechanical properties of the fractured tibias and the nanomechanical properties of the calluses were investigated through three-point bending and nanoindentation tests, respectively. Atomic force microscopy (AFM) was performed to analyze the nanostructure of the calluses. Micro-computed tomography (micro-CT) scanning was conducted to evaluate the microarchitecture of the calluses. The serum concentration of osteocalcin (OG) and tartrate-resistant acid phosphatase 5b (TRAP5b) were measured to assess the bone formation and resorption rates, respectively. Significantly higher values of failure load and elastic modulus were observed in DL (vibrational loading for 15 min per day) and DLR (vibrational loading per day in which three bouts of 5 min of vibration were separated by 4 h) than FBC (fractured model without mechanical loading) at macro-level (
P
< 0.05). The results of nanoindentation test showed the highest values of indentation modulus and hardness in DLR (significantly higher than FBC;
P
< 0.05); besides, higher value of hardness was also observed in DL (significantly higher than FBC;
P
< 0.05). Though AFM imaging showed no significant differences in grain sizes between the vibrational groups and FBC, roughness of DLR showed the highest value, i.e. it was significantly higher than that in FBC (
P
< 0.05). For microarchitectural parameters obtained from micro-CT imaging, tissue mineral density (TMD) of DLR and VL7 (vibrational loading for 7 day followed by a 7-day rest, 15 min per day during vibrational periods) were significantly higher than that in FBC (
P
< 0.05), but no significant differences in other parameters were observed between vibrational groups and FBC. There were no significant differences of OG between vibrational groups and FBC; however, FBC showed significantly higher TRAP5b concentration than all vibrational groups (
P
< 0.05). The results show that LMHFV with different rest period regimes not only altered the macro- and nano-level bone mechanical properties but also influenced the TMD of calluses and nano-level spatial arrangement (roughness) significantly. The most significant effect of LMHFV with different rest period regimes was observed in DLR, which indicated that both osteogenic accumulation and cellular resensitization can be satisfied under this regimen. Hence, the DLR group demonstrated a great potential in clinical applications.
The aim of this study is to investigate the flocculation capacity of activated sludge flocculant in chromium ion and nitrobenzene solutions. Besides comparing with activated carbon, we changed some ...potential factors which may influence the flocculation, such as solution pH value, reaction time, flocculant dosage, and solution initial concentration, and tested the flocculation capacity of this bioflocculant for both chromium and nitrobenzene. In addition, the flocculation of activated sludge after acidic or alkali modification for double solutions was also estimated. Compared with activated carbon, the activated sludge flocculant showed a good flocculation capacity for nitrobenzene, but poor flocculation for chromium following the initial concentration increase. The flocculation for nitrobenzene or chromium increased at initial stage and decreased gradually following the primary dosage of flocculant increase. The flocculation for nitrobenzene increased at the primary stage and decreased after peak, while the flocculation for chromium increased following the pH increase of both solutions. Although the flocculation for nitrobenzene decreased, the flocculation for chromium increased obviously, when we prolonged the reaction time. The flocculant showed a gradual increasing trend in double kinds of solution when they were heating. The flocculation for both nitrobenzene and chromium decreased after acid modification of activated sludge flocculant, while the flocculation increased after basic modification. The present research provided further theoretical basis of the biosorption of heavy metal waste water and nitrobenzene organic toxicants.
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