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Soil erosion and extensive management, as key factors limiting the sustainability of the agroecosystem in the Loess Plateau, severely hamper the high-quality development of regional agriculture. Soil fertility and element synergy can be enhanced by applying mulching measures properly. However, there is a lack of systematic research into how soil stoichiometric characteristics under mulching affect crop productivity. This study focused on the agroecosystem of the Loess Plateau. Based on the 11-year field positioning experiment, the management measures of straw mulching (SM), plastic mulching (PM) and ridge-film mulching (RM) were selected to investigate the effects of long-term mulching measures on the stoichiometric characteristics of topsoil and the impact of crop productivity under the ecological stoichiometry theory. The findings revealed a significant increase in soil carbon, nitrogen and phosphorus contents and microbial biomass under mulching. SM and RM significantly decreased the stoichiometric ratio of soil available nutrients, whereas PM and RM had effective alleviating effects on C:N and C:P imbalance. The yield components of long-term SM and RM greatly increased and responded favorably to the synergy of soil carbon and phosphorus. This study provides theoretical guidance and technical support for the assessment of the effective and sustainable use of agricultural resources on the Loess Plateau. [ABSTRACT FROM AUTHOR]

In the pulsed electroacoustic (PEA) space charge measurement system used for coaxial cables, the waveform of a coupled pulse will directly affect space charge profiles in cable insulation. In this paper, on the basis of the PEA measurement system with pulse injection from a measuring electrode, the original charge acoustic signals in a 35 kV cross-linked polyethylene (XLPE) cable were collected directly from the oscilloscope under different ground distances between the measuring point and the ground point along a cable's semiconductive (SC) layer. At the same time, the effects of ground distance, cable specification, and cable length on the waveform of a coupled pulse were studied through a series of experiments and simulations. The results show that the amplitude of the coupled pulse is directly proportional to the ground distance but inversely proportional to the cable cross section or voltage class. Furthermore, the pulse coupling efficiency is almost the same only if the cables have the same diameter of the outer SC layer. Therefore, a constant pulse coupling efficiency can be obtained by adjusting the ground distance according to the diameter of the cable's outer SC layer. [ABSTRACT FROM AUTHOR]

Here, we investigated the effects of straw returning combined with biochar application on summer maize yield and soil nitrous oxide (N 2 O) emissions, based on a field location trial in the Guanzhong Plain from 2019 to 2020. The soil N 2 O emission rates were monitored using the static chamber-chromatography method. A comprehensive analysis of summer maize yields, soil N 2 O emissions, and soil labile nitrogen components was conducted to clarify the effects of straw returning combined with biochar application on improving soil fertility, increasing summer maize yield, and reducing greenhouse gas emissions. The three treatments were no straw returning (S 0 ), straw returning (S), and straw returning combined with biochar application (SB). The results showed that the peak of N 2 O emissions from each treatment occurred 10 d after the straw return, and the rate of soil N 2 O emissions remained at a low level after 30 d of straw return. The rate of soil N 2 O emissions showed highly significant positive correlations ( P <0.05) with ammonium nitrogen (NH 4 + -N), inorganic nitrogen (SIN), microbial nitrogen (MBN), and dissolved organic nitrogen (DON) contents. S significantly increased summer maize yield, cumulative N 2 O emissions, yield-scaled N 2 O intensity, and total nitrogen (TN) content by 7.4%-13%, 65.8%-132.2%, 54.6%-103%, and 27.8%-33%, respectively, compared to those in S 0 . Although the trend for SB to increase summer maize yield (2.5%-3.3%) compared to that in S was not significant ( P >0.05), SB significantly reduced cumulative N 2 O emissions and yield-scaled N 2 O intensity by 24.0%-27.3% and 26.4%-29.2%, respectively, compared to that in S. SB significantly reduced the rate of soil N 2 O emissions by 45.1%-69.6% at the peak of N 2 O emissions compared to that in S. Biochar application mitigated soil N 2 O emissions induced by straw return and had a peak-shaving effect. SB significantly increased soil total N by 9.1%-12.2% compared to that in S. Combining summer maize yield, soil N 2 O emissions, and TN content, SB not only improved soil fertility and summer maize yield but also reduced yield-scaled N 2 O intensity, making it a suitable management practice that can be replicated to balance crop yield and environmental friendliness.

Objective To assess the effects of vascular endothelial growth factor-C (VEGF-C)/vascular endothelial growth factor receptor-3 (VEGFR-3) signaling on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in human osteosarcoma MG63 cells and the subsequent impact on the proliferation of human umbilical vein endothelial cells (HUVECs). MethodsMG63 cells were treated with VEGF-C alone (VEGF-C group), VEGF-C + iNOS inhibitor aminoguanidine (AG; AG group), and VEGF-C + VEGFR-3 inhibitor MAZ51 (MAZ51 group); untreated MG63 cells were used as controls. NO production was evaluated by a colorimetric method involving nitrate reductase. Meanwhile, mRNA and protein levels of iNOS were examined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. To explore the effect of VEGF-C/VEGFR-3/iNOS signaling of MG63 cells on proliferation of HUVECs, we set up six groups: HUVECs, HUVECs+MG63, HUVECs+VEGF-C, HUVECs+MG63+VEGF-C, HUVECs+MG63+VEGF-C+AG, and HUVECs+MG63+VEGF-C+MAZ51 groups. The proliferation of HUVEC cells was assessed by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, and proliferating cell nuclear antigen (PCNA) expression quantitation. ResultsVEGF-C treatment enhanced iNOS expression at both gene and protein levels (mRNA: LSD- t =4.152, P<0.01 ; protein: LSD- t =3.486, P<0.01 ) and increased NO release of MG63 cells (LSD- t =3.774, P<0.01 ); treatment with either AG or MAZ51 decreased these effects (mRNA: LSD- t =9.183, P <0.001; LSD- t =8.639, P <0.001; protein: LSD- t =5.170, P <0.001; LSD- t =7.255, P <0.001; NO production:LSD- t =10.326, P <0.001; LSD- t =10.540, P <0.001). Interestingly, co-incubation of HUVECs with MG63 cells and/or VEGF-C significantly promoted HUVEC proliferation (EdU: LSD- t =5.374, P< 0.001; LSD- t =2.984, P< 0.05; LSD- t =8.526, P< 0.001; PCNA: LSD- t =9.267, P <0.001; LSD- t =5.515, P< 0.001; LSD- t =14.873, P< 0.001).The proliferation effects of HUVEC induced by MG63 cells and VEGF-C attenuated by the treatment of AG (EdU: LSD- t =10.770, P< 0.001; PCNA: LSD- t =19.940, P <0.001) or MAZ51 (EdU: LSD- t =6.950, P< 0.001; PCNA: LSD- t =14.001, P <0.001). ConclusionIn human osteosarcoma MG63 cells, activation of VEGFR-3 by VEGF-C promotes iNOS expression and NO production, which subsequently induces HUVEC proliferation.

In order to explore the impacts of nitrogen fertilizer and straw returning methods on N 2 O emissions, a two-factor split-zone design was adopted for experimentation under the winter wheat-summer maize rotation model in the Guanzhong area of Shanxi, China. The main areas of interest were conventional nitrogen (G) and reduced nitrogen (70% G); the sub-areas were straw no return (N), straw return (S), and straw return + biochar (SB); we analyzed their impacts on N 2 O emissions and crop yield, and the relationships with related impact factors. The results showed that the N 2 O emissions peaks appeared in the wheat season and maize season treatments within 5-16 days after fertilization, and also appeared after rainfall. The N 2 O flux was significantly and positively correlated with soil temperature and NH 4 + -N content. Regardless of the wheat season, maize season, or annual total N 2 O emissions, the 70% GSB treatment was the lowest and the GS treatment was the highest. At the same level of nitrogen application, S treatment increased N 2 O emissions, SB treatment could reduce N 2 O emissions, both S and SB treatments could significantly increase crop yields, and SB production increased more; 70%G-level annual N 2 O emissions, when compared with the G level, had been reduced by 40% to 48%, while the yield has not decreased significantly. Through comprehensive consideration, a reduction of nitrogen by 30% was achieved through the combination of straw + biochar on the basis of conventional nitrogen application, while ensuring high crop yields and the best N 2 O emissions reduction.

Aim: To investigate the difference in long-term outcomes between gastric cancer patients with and without a primary symptom of overt bleeding (OB)., Methods: Consecutive patients between January 1, 2007 and March 1, 2012 were identified retrospectively by reviewing a gastric cancer database at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. A follow-up examination was performed on patients who underwent a radical gastrectomy. OB due to gastric cancer included hematemesis, melena or hematochezia, and gastric cancer was confirmed as the source of bleeding by endoscopy. Patients without OB were defined as cases with occult bleeding and those with other initial presentations, including epigastric pain, weakness, weight loss and obstruction. The 3-year overall survival (OS) rate, age, gender, AJCC T stage, AJCC N stage, overall AJCC stage, tumor size, histological type, macroscopic (Borrmann) type, lymphovascular invasion and R status were compared between patients with and without OB. Moreover, we carried out a subgroup analysis based on tumor location (upper, middle and lower)., Results: We identified 939 patients. Of these, 695 (74.0%) were hospitalized for potential radical gastrectomy and another 244 received palliative resection, rerouting of the gastrointestinal tract, chemotherapy, radiotherapy or no treatment due to the presence of unresectable tumors. Notably, there was no significant difference in the percentage of OB patients between resectable cases and unresectable cases (20.3% vs 22.1%, P = 0.541). Follow-up examination was performed on 653 patients (94%) who underwent radical gastrectomy. We found no significant difference in 3-year OS rate (68.2% vs 61.2%, P = 0.143) or clinicopathological characteristics (P > 0.05) between these patients with and without OB. Subgroup analysis based on tumor location showed that the 3-year OS rate of upper gastric cancer was significantly higher in patients with OB (84.6%) than in those without OB (48.1%, P < 0.01) and that AJCC stages I-II (56.4% vs 35.1%, P = 0.017) and T1-T2 category tumors (30.8% vs 13%, P = 0.010) were more frequent in patients with OB than in those without OB. There was no significant difference in 3-year OS rate or clinicopathological characteristics between patients with and without OB (P > 0.05) for middle or lower gastric cancer., Conclusion: Upper gastric cancer patients with OB exhibited tumors at less advanced pathological stages and had a better prognosis than upper gastric cancer patients without OB.