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1.
J Am Coll Radiol ; 17(1 Pt B): 101-109, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31918865

RESUMO

OBJECTIVE: To evaluate whether the implementation of a new population-based primary care payment system, Population-Based Payments for Primary Care (3PC), initiated by Hawaii Medical Service Association (HMSA; the Blue Cross Blue Shield of Hawaii), was associated with changes in spending and utilization for outpatient imaging in its first year. METHODS: In this observational study, we used claims data from January 1, 2012, to December 31, 2016. We used a propensity-weighted difference-in-differences design to compare 70,284 HMSA patients in Hawaii attributed to 107 primary care physicians (PCPs) and 4 physician organizations participating in 3PC in its first year of implementation (2016) and 195,902 patients attributed to 312 PCPs and 14 physician organizations that used a fee-for-service model during the study period. The primary outcome was total spending on outpatient imaging tests, and secondary outcomes included spending and utilization by modality. RESULTS: The study included 266,186 HMSA patients (mean age of 43.3 years; 51.7% women) and 419 PCPs (mean age of 54.9 years; 34.8% women). The 3PC system was not significantly associated with changes in total spending for outpatient imaging. Of 12 secondary outcomes, only 3 were statistically significant, including changes in nuclear medicine spending (adjusted differential change = -20.1% [95% confidence interval = -27.5% to -12.1%]; P < .001) and utilization (adjusted differential change = -18.1% [95% confidence interval = -23.8 to -11.9%]; P < .001). DISCUSSION: The HMSA 3PC system was not associated with significant changes in total spending for outpatient imaging, though spending and utilization on nuclear medicine tests decreased.

2.
Cancer Lett ; 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31911080

RESUMO

The AT-rich interaction domain 1A (ARID1A, also known as BAF250a) is a chromatin remodeling gene, which frequently mutates across a broad spectrum of cancers with loss expression of the ARID1A protein. Recently, the association between ARID1A deficiency and immune checkpoint blockade (ICB) therapy has been reported. ARID1A deficiency contributes to the high microsatellite instability phenotype, increases tumor mutation burden, elevates expression of programmed cell death ligand 1 (PD-L1), and modulates the immune microenvironment, supporting the view that ARID1A loss might serve as a predictive biomarker for ICB. Furthermore, the therapeutic targeting strategies, which show "synthetic lethality" with ARID1A deficiency, exhibit potential synergy with ICB. We collectively reviewed the mechanisms underlying the correlation between ARID1A deficiency and ICB, the predictive function of ARID1A deficiency for ICB, and potential combined strategies of targeting agents, vulnerable for ARID1A deficiency, with ICB in cancer treatment.

3.
Wien Klin Wochenschr ; 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31912286

RESUMO

BACKGROUND: The aim of this study was to investigate the association between self-rated eyesight and handgrip strength in a large, representative population of older adults. METHODS: Data were from 7433 older adults (≥52 years) participating in the English Longitudinal Study of Ageing. Linear regression was used to analyze the association between self-rated eyesight and handgrip strength cross-sectionally in 2004/2005, and longitudinally over 4­year follow-up, adjusting for a range of sociodemographic and health-related variables. RESULTS: In cross-sectional and prospective models, poor eyesight was strongly associated with lower handgrip strength after adjustment for age, sex, ethnicity, socioeconomic status and body mass index (BMI, cross-sectional B = -1.39 kg, 95% confidence interval, CI -1.84 to -0.94, p < 0.001, prospective B = -0.68 kg, 95% CI -1.14 to -0.22, p = 0.004). The association was attenuated but remained statistically significant when health behaviours were included in the model (cross-sectional B = -0.93 kg, 95% CI -1.42 to -0.44, p < 0.001, prospective B = -0.50, 95% CI -0.99 to -0.02, p = 0.044). CONCLUSION: Older adults in England with poor self-rated eyesight have lower levels of physical function compared with those with good eyesight. This association can be predominantly explained by differences in age, sex, ethnicity, socioeconomic status, BMI, and health behaviours, as well as chronic conditions, disability and depression.

4.
Cancer Res ; 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31915129

RESUMO

The spatial organization of different types of cells in tumor tissues reveals important information about the tumor microenvironment (TME). In order to facilitate the study of cellular spatial organization and interactions, we developed Histology-based Digital (HD)-Staining, a deep learning-based computation model, to segment the nuclei of tumor, stroma, lymphocyte, macrophage, karyorrhexis and red blood cells from standard Hematoxylin and Eosin (H&E)-stained pathology images in lung adenocarcinoma (ADC). Using this tool, we identified and classified cell nuclei and extracted 48 cell spatial organization-related features that characterize the TME. Using these features, we developed a prognostic model from the National Lung Screening Trial dataset, and independently validated the model in The Cancer Genome Atlas (TCGA) lung ADC dataset, in which the predicted high-risk group showed significantly worse survival than the low-risk group (pv=0.001), with a hazard ratio of 2.23 [1.37-3.65] after adjusting for clinical variables. Furthermore, the image-derived TME features significantly correlated with the gene expression of biological pathways. For example, transcriptional activation of both the T-cell receptor (TCR) and programmed cell death protein 1 (PD1) pathways positively correlated with the density of detected lymphocytes in tumor tissues, while expression of the extracellular matrix organization pathway positively correlated with the density of stromal cells. In summary, we demonstrate that the spatial organization of different cell types is predictive of patient survival and associated with the gene expression of biological pathways.

5.
Commun Biol ; 3(1): 22, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31925310

RESUMO

LXYL-P1-2 is one of the few xylosidases that efficiently catalyze the reaction from 7-ß-xylosyl-10-deacetyltaxol (XDT) to 10-deacetyltaxol (DT), and is a potential enzyme used in Taxol industrial production. Here we report the crystal structure of LXYL-P1-2 and its XDT binding complex. These structures reveal an enzyme/product complex with the sugar conformation different from the enzyme/substrate complex reported previously in GH3 enzymes, even in the whole glycohydrolases family. In addition, the DT binding pocket is identified as the structural basis for the substrate specificity. Further structure analysis reveals common features in LXYL-P1-2 and Taxol binding protein tubulin, which might provide useful information for designing new Taxol carrier proteins for drug delivery.

6.
J Mol Neurosci ; 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897968

RESUMO

Schizophrenia is a severe chronic neuropsychiatric disorder, and it negatively affects individuals' quality of life, but the pathogenesis of schizophrenia remains unclear. This study aimed to explore whether the administration of ketamine in rats causes changes in mTOR (mechanistic/mammalian target of rapamycin) expression in the hippocampus and prefrontal cortex. Ketamine was used to establish an animal model of schizophrenia. Rats were randomly divided into four groups: control group (normal saline), low-dose group (15 mg/kg ketamine), middle-dose group (30 mg/kg ketamine), and high-dose group (60 mg/kg ketamine). The rats were intraperitoneally injected with ketamine or normal saline twice a day (9 AM and 9 PM) for 7 consecutive days. Immunohistochemistry was used to detect mTOR protein expression in the hippocampus and prefrontal cortex from rats at 13 h after the last treatment. Using immunohistochemistry, the expression of the mTOR protein was localized exclusively in the CA3 region of the hippocampus and in the Cg1 region of the prefrontal cortexes. Ketamine at 60 mg/kg decreased the expression of mTOR protein in the brain of rats. Ketamine successfully established a rat model of schizophrenia. This study helps elucidate the mechanisms of ketamine-induced schizophrenia and provides novel insights for drug discovery and development.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31835745

RESUMO

The purpose of this study is to explore the spatial distribution pattern and influencing factors of the Chinese marathon. Geographic Information System (GIS) related spatial analysis tools were used to calculate the following-averaged nearest neighbor index, nuclear density analysis and hot spot analysis among others. The spatial distribution evolution characteristics and the influencing factors of eighteen Chinese marathon events in 2010, 129 in 2015 and 342 in 2018 were analyzed. The results show that (a) in 2010 the nearest neighbor ratio was 1.164714, Moran's I was -0.010165 (type: Random), in 2015 it was 0.502146, Moran's I was 0.066267 (type: Clustered) and in 2018 it was 0.531149 and Moran's I was 0.083485 (type: Clustered); (b) in 2010 there was a 333.6 km search radius; the core circle of the Yangtze River Delta was adopted. In 2015 and 2018, a search radius of 556 km was adopted, which was respectively obtained from the core circle of the Yangtze River Delta, the core circle of Beijing-Tianjin-Hebei and the core circle of East China; (c) according to the Z-value data, East China and North China in 2015 passed 95% confidence in five provinces and municipal hot spots, passed 90% confidence in three hot spots and passed 95% confidence in Chongqing Cold Point. In 2018, East China, North China, Central Region and eight other provinces and cities' hot spots passed 95% confidence, four hot spots passed 90% confidence, the Tibet Autonomous Region cold spot passed 90% confidence. Conclusion: The overall distribution of marathon events is greater in the eastern region than the western region, greater in the southern region than the northern region and greater in coastal regions than the inland regions; the nuclear density distribution has spread from the Yangtze River Delta mononuclear circle in 2010 to the core circle of the entire East China region. Moreover, it spread to North China, Central China and South China; the distribution of hot spots spread from Shanghai, Jiangsu and Zhejiang to the entire North China and East China regions. During the past thirty-eight years of development of the Chinese marathon, it has been divided into three stages due to different political, economic and social environments.

8.
Nat Commun ; 10(1): 5480, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31792204

RESUMO

Covalently linked π-stacked dimers represent the most significant platform for elucidating the relationship between molecular alignments and their properties. Here, we present the one-pot synthesis of two intramolecularly π-stacked dimers and disclose how intramolecular stacking modes dictate photoswitching properties. The dimer, which features cofacially stacked chromophores and geometrically favours intramolecular photochemical [2 + 2] cycloadditions, displays a nearly irreversible photoswitching behaviour. By contrast, the dimer, bearing crosswise stacked chromophores, is geometrically unfavourable for the cycloaddition and exhibits a highly reversible photoswitching process, in which the homolysis and reformation of carbon-carbon single bonds are involved. Moreover, the chiral carbon centres of both dimers endow these photoswitches with chirality and the separated enantiomers exhibit tuneable chiroptical properties by photoswitching. This work reveals that intramolecular stacking modes significantly influence the photochemical properties of π-stacked dimers and offers a design strategy toward chiral photoswitchable materials.

9.
Int J Mol Sci ; 20(24)2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31817701

RESUMO

To elucidate the effect of rice protein (RP) on the depression of inflammation, growing and adult rats were fed with caseins and RP for 2 weeks. Compared with casein, RP reduced hepatic accumulations of reactive oxygen species (ROS) and nitro oxide (NO), and plasma activities of alanine transaminase (ALT) and aspartate transaminase (AST) in growing and adult rats. Intake of RP led to increased mRNA levels, and protein expressions of phosphoinositide 3 kinase (PI3K), protein kinase B (Akt), nuclear factor-κB 1 (NF-αB1), reticuloendotheliosis viral oncogene homolog A (RelA), tumor necrotic factor α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and monocyte chemoattractant protein-1 (MCP-1) were decreased, whereas hepatic expressions of interleukin-10 (IL-10) and heme oxygenase 1 (HO-1) were increased by RP. The activation of NF-κB was suppressed by RP through upregulation of inhibitory κB α (IκBα), resulting in decreased translocation of nuclear factor-κB 1 (p50) and RelA (p65) to the nucleus in RP groups. The present study demonstrates that RP exerts an anti-inflammatory effect to inhibit ROS-derived inflammation through suppression of the NF-κB pathway in growing and adult rats. Results suggest that the anti-inflammatory capacity of RP is independent of age.

10.
Sci Rep ; 9(1): 18682, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31822782

RESUMO

The ground-state α phase of plutonium has an extraordinary 16-atom per cell, monoclinic crystal structure defined by 20 parameters, including the cell dimensions, not dictated by the symmetry. The electronic, magnetic, and elastic properties of this complicated material have been predicted in the past but here we compute its phonon spectra. Employing a density-functional-theory (DFT) model, that is fully relativistic and accounts for orbital-orbital coupling (orbital polarization, OP), we determine the phonon density of states of α-plutonium and find good agreement with inelastic x-ray scattering. The calculated specific heat also compares very favorably with experiment. An analysis of the partial atom-projected phonon spectra suggests that atom type 8, that is located in a more open space of the structure, dominates the intensity at very high phonon frequencies. This feature of the model is essential for a good agreement with the experimental spectra. The satisfactory comparison between theory and experiment for the phonons and specific heat suggests that the DFT (+OP) approach is appropriate and accurate for α-plutonium.

11.
Genomics ; 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31786291

RESUMO

Finding reliable markers for predicting the efficacy of immunotherapy is urgently needed. We sought to investigate the association between serum microRNAs (miRNAs) and checkpoint inhibitor response in non-small cell lung cancer (NSCLC). Discovery assay with sera miRNA profiling was performed, demonstrating 27 sera miRNAs (relative fold >2, p < .05), 22 higher expressed and 5 lower expressed miRNAs, were differentially expressed in 19 responders compared to those in 27 non-responders. Further validation validated miR-93, -138-5p, -200, -27a, -424, -34a, -28, -106b, -193a-3p, and -181a were significantly higher expressed (p < .01) in an independent cohort of 17 responders vs. 17 non-responders. Longitudinally, responders had increased sera expression levels of miR-93, -138-5p, -200, -27a, -424, -34a, -28, -106b, -193a-3p, and -181a from pre-treatment to post-treatment (p < .01). More importantly, statistically significant improvement in PFS of patients was associated with the 10-high expressed miRNA pattern (median PFS of 6.25 versus 3.21 months, p < .001; hazard ratio, HR, 0.45; 95% CI, 0.25-0.76). Further OS improvement was also significantly associated with the 10-high expressed miRNA pattern in responders versus non-responders (median OS of 7.65 versus 3.2 months, p < .001, HR, 0.39; 95% CI, 0.15-0.68). In conclusion, these results demonstrated that alterations in circulating miRNAs are associated with the response and outcome in NSCLC patients treated with anti-PD1 drugs.

12.
Biocybern Biomed Eng ; 39(3): 806-813, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31787794

RESUMO

The aims of this study were to apply decision tree to classify uterine activities (contractions and non-contractions) using the waveform characteristics derived from different channels of electrohysterogram (EHG) signals and then rank the importance of these characteristics. Both the tocodynamometer (TOCO) and 8-channel EHG signals were simultaneously recorded from 34 healthy pregnant women within 24 h before delivery. After preprocessing of EHG signals, EHG segments corresponding to the uterine contractions and non-contractions were manually extracted from both original and normalized EHG signals according to the TOCO signals and the human marks. 24 waveform characteristics of the EHG segments were derived separately from each channel to train the decision tree and classify the uterine activities. The results showed the Power and sample entropy (SamEn) extracted from the un-normalized EHG segments played the most important roles in recognizing uterine activities. In addition, the EHG signal characteristics from channel 1 produced better classification results (AUC = 0.75, Sensitivity = 0.84, Specificity = 0.78, Accuracy = 0.81) than the others. In conclusion, decision tree could be used to classify the uterine activities, and the Power and SamEn of un-normalized EHG segments were the most important characteristics in uterine contraction classification.

13.
Aquat Toxicol ; 218: 105352, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31790938

RESUMO

Cadmium (Cd) affects plants and animal health seriously. Ca2+ signals in plant cells are important for adaptive responses to environmental stresses. Here we showed that 50 µM Cd shock stimulated the Ca2+ signal via modifying the instantaneous Ca2+ flux from influx of 17 pmol·cm-2·s-1 to the efflux of 240 pmol·cm-2·s-1 at 100 µm from rhizoid tip. And the Ca2+ signal transferred to the vein and mesophyll cell. The Ca addition decreased the accumulation of Cd. The gene expression of glutamate receptor-like (GLR) proteins, which is activated by Glu and triggers Ca2+ flux, was increased significantly by 24 h Cd stress. Glu content was increased under Cd stress and exogenous Glu triggered the Ca2+ signal in duckweed, while Ca2+ addition caused no influence to Glu content. GABA, which is synthesized from Glu and acts as an inhibitory neurotransmitter, has been decreased with 24 h Cd treatment. GABA addition increased the abscission rate and Glu addition decreased the abscission rate during Cd stress, suggesting that the Glu/GABA ratio is important for responding to Cd. This research shows the sight of the Glu, Ca2+, GABA signaling networks during Cd stress.

14.
J Asian Nat Prod Res ; : 1-10, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31791147

RESUMO

Various bioactive polyketides have been found in Aloe barbadensis. However, the polyketide synthases (PKSs), which participate in biosynthesis of polyketides in A. barbadensis remain unknown. In this study, two type III PKSs (AbPKS1 and AbPKS2) were identified from A. barbadensis. AbPKS1 and AbPKS2 were able to utilize malonyl-CoA to yield heptaketides (TW93a and aloesone) and octaketides (SEK4 and SEK4b), respectively. AbPKS1 also exhibited catalytic promiscuity in recognizing CoA thioesters of aromatics to produce unusual polyketides. What Is more, a whole cell biocatalysis system with the capability of producing 26.4 mg/L of SEK4/SEK4b and 2.1 mg/L of aloesone was successfully established.

15.
Cancer Commun (Lond) ; 39(1): 81, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31796105

RESUMO

BACKGROUND: High-grade glioma (HGG) is a fatal human cancer. Bortezomib, a proteasome inhibitor, has been approved for the treatment of multiple myeloma but its use in glioma awaits further investigation. This study aimed to explore the chemotherapeutic effect and the underlying mechanism of bortezomib on gliomas. METHODS: U251 and U87 cell viability and proliferation were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, tumor cell spheroid growth, and colony formation assay. Cell apoptosis and cell cycle were detected by flow cytometry. Temozolomide (TMZ)-insensitive cell lines were induced by long-term TMZ treatment, and cells with stem cell characteristics were enriched with stem cell culture medium. The mRNA levels of interested genes were measured via reverse transcription-quantitative polymerase chain reaction, and protein levels were determined via Western blotting/immunofluorescent staining in cell lines and immunohistochemical staining in paraffin-embedded sections. Via inoculating U87 cells subcutaneously, glioma xenograft models in nude mice were established for drug experiments. Patient survival data were analyzed using the Kaplan-Meier method. RESULTS: Bortezomib inhibited the viability and proliferation of U251 and U87 cells in a dose- and time-dependent manner by inducing apoptosis and cell cycle arrest. Bortezomib also significantly inhibited the spheroid growth, colony formation, and stem-like cell proliferation of U251 and U87 cells. When administrated in combination, bortezomib showed synergistic effect with TMZ in vitro and sensitized glioma to TMZ treatment both in vitro and in vivo. Bortezomib reduced both the mRNA and protein levels of Forkhead Box M1 (FOXM1) and its target gene Survivin. The FOXM1-Survivin axis was markedly up-regulated in established TMZ-insensitive glioma cell lines and HGG patients. Expression levels of FOXM1 and Survivin were positively correlated with each other and both related to poor prognosis in glioma patients. CONCLUSIONS: Bortezomib was found to inhibit glioma growth and improved TMZ chemotherapy efficacy, probably via down-regulating the FOXM1-Survivin axis. Bortezomib might be a promising agent for treating malignant glioma, alone or in combination with TMZ.

16.
Sci Rep ; 9(1): 18248, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31796756

RESUMO

Vascular dementia (VaD) is a complex disorder caused by reduced blood flow in the brain. However, there is no effective pharmacological treatment option available until now. Here, we reported that low-dose levamlodipine besylate could reverse the cognitive impairment in VaD mice model of right unilateral common carotid arteries occlusion (rUCCAO). Oral administration of levamlodipine besylate (0.1 mg/kg) could reduce the latency to find the hidden platform in the MWM test as compared to the vehicle group. Furthermore, vehicle-treated mice revealed reduced phospho-CaMKII (Thr286) levels in the hippocampus, which can be partially restored by levamlodipine besylate (0.1 mg/kg and 0.5 mg/kg) treatment. No significant outcome on microglia and astrocytes were observed following levamlodipine besylate treatment. This data reveal novel findings of the therapeutic potential of low-dose levamlodipine besylate that could considerably enhance the cognitive function in VaD mice.

17.
J Sex Med ; 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31812682

RESUMO

INTRODUCTION: Physical activity is likely to be associated with sexual activity. However, to date, there is no literature on the relationship between overweight/obesity and sexual activity outcomes. AIM: Thus, the present study assessed the associations among physical activity, sedentary behavior, and weight status with sexual activity and number of previous sexual partners in a representative sample of U.S. adults. METHODS: Data on leisure time physical activity, total sitting time, weight status, sexual behavior outcomes, and other characteristics were extracted from the National Health and Nutrition Study cycle 2007 to 2016. Logistic regression models were used to evaluate associations among body mass index, leisure time physical activity, and total sitting time with past-year sexual activity and number of sexual partners. MAIN OUTCOME MEASURE: Self reported frequency of past-year sexual activity and number of sex partners in the past year. RESULTS: In a sample of 7,049 men (mean age: 38.3 ± 0.3 years) and 7,005 women (mean age: 38.7 ± 0.2 years) being overweight was associated with higher odds of frequent sexual activity (OR = 1.5; 95% CI = 1.2-1.7) among men, but lower odds among women (OR = 0.8; 95% CI = 0.6-0.9). Sufficient physical activity was associated with higher odds of frequent sexual activity among both men (OR = 1.3; 95% CI = 1.1-1.5) and women (OR = 1.2; 95% CI = 1.0-1.4). In those living alone, being obese was associated with lower odds of having at least 1 sexual partner for men (OR = 0.7; 95% CI = 0.5-0.9) and women (OR = 0.6; 95% CI = 0.4-0.8). Being sufficiently physically active was associated with higher odds of having at least 1 sexual partner only in men (OR = 1.6; 95% CI = 1.2-2.2). CLINICAL IMPLICATIONS: Healthcare professionals need to be made aware of these results, as they could be used to plan tailored interventions. STRENGTHS & LIMITATIONS: Strengths include the large, representative sample of U.S. adults and objective measures of anthropometry. Limitations include the cross-sectional design of the study and that all variables on sexual history were self-reported. CONCLUSION: The present study identifies novel modifiable behavioral and biological antecedents of sexuality outcomes. Grabovac I, Cao C, Haider S, et al. Associations Between Physical Activity, Sedentary Behavior and Weight Status With Sexuality Outcomes: Analyses from National Health and Nutrition Examination Survey. J Sex Med 2019;XX:XXX-XXX.

18.
Huan Jing Ke Xue ; 40(7): 3388-3396, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854742

RESUMO

The effect of biochar on the bulk density and aggregate stability of Lou soil was evaluated and compared after biochar was applied for 2 years and 5 years through a field-positioning experiment. Five biochar amounts were applied in this study, as follows:0 t·hm-2 (B0), 20 t·hm-2 (B20), 40 t·hm-2 (B40), 60 t·hm-2 (B60), and 80 t·hm-2 (B80). The biochar was produced by pyrolysis of stems and branches from fruit trees at the temperature of 450℃ with limited oxygen apply. At the beginning of the study, biochar was mixed thoroughly with the surface soil (0-20 cm). After 5 years, the soil bulk density and aggregate stability of 0-30 cm soil layers (0-10, 10-20, and 20-30 cm) were measured and compared with the results obtained after 2 years with the purpose of observing the long-term and persist effects of biochar application. The results showed that:① compared with the results after 2 years of application, the effect of biochar on the aggregates at depths of 0-10 cm and 10-20 cm after 5 years were less distinct, and the effect on soil aggregates at depths of 20-30 cm was significantly enhanced; ② compared with the 2 year application, the aggregate stability and the content of the>0.25 mm aggregate size fraction were significantly increased at 0-10 cm depths after 5 years of biochar application at a rate of 40 t·hm-2, while bulk density was significantly decreased; at 10-20 cm and 20-30 cm soil depths, the stability of aggregates and the content of the>0.25 mm aggregate size fraction was significantly increased, while the bulk density was significantly decreased after 5 years of biochar application at a rate of 60-80 t·hm-2;③ when the biochar application rate was 60 t·hm-2, the increase in soil organic carbon was the highest after 5 years. After biochar was applied for 5 years, its effect was more significant lower in the soil profile; the soil bulk density was significantly reduced, and aggregate stability and the content of>0.25 mm aggregates were significantly increased at depths of 20-30 cm. Based on a comprehensive evaluation of the improvement effects and economic benefits, the most suitable biochar application rate was found to be 40-60 t·hm-2. It was further concluded that the effect of biochar on soil aggregates was gradual and sustainable.

19.
Huan Jing Ke Xue ; 40(8): 3746-3752, 2019 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854784

RESUMO

Nitrification inhibitor and biochar are commonly used as soil synergists. Among them, nitrification inhibitor can increase crop yields and N use efficiency, while biochar is a relatively new way of using biomass resources and has certain adsorption characteristics. In order to reduce nitrogen loss and environmental pollution caused by ammonia volatilization in paddy fields, a pot experiment with chemical fertilizer application (CN) as a control was conducted to study the effects of biochar (B), nitrapyrin (CP), and compound application (BCP) on pH, NH4+-N concentration dynamics in the flood water, rice yields, and ammonia volatilization from paddy fields. The results showed that the application of these two synergists had no significant effect on rice yields, and the nitrification inhibitors had a tendency to increase rice yields. The two synergists significantly increased ammonia volatilization from paddy fields, accounting for 25%-35% of the total N rate. Ammonia volatilization during periods of fertilizer application accounted for 86%-91% of the total loss, representing the main period of ammonia volatilization. Compared with the CN treatment, the CP treatment increased NH4+-N concentrations in flood water and the loss of ammonia via volatilization, which was increased by 59.18% and mainly occurred during a week after the basal fertilization(138%) and spike fertilization (48%), and non-fertilization stage (78%). Biochar had a promoting effect on ammonia volatilization with typically phased characteristics. The initial increasing effect of biochar on ammonia volatilization was higher than during the later stages, when NH4+-N concentrations and the pH of flood water showed the same trend. In addition, the coupling of nitrification inhibitor and biochar significantly increased the total loss of ammonia via volatilization loss due to the promotion effect of CP and B. The problem of increased ammonia volatilization loss caused by the application of nitrification inhibitors requires further research.

20.
Huan Jing Ke Xue ; 40(9): 4072-4080, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854870

RESUMO

Natural iron-containing minerals present in the geosphere in the form of crystalline minerals can be used as adsorption material for removal of arsenic from wastewater and remediation of arsenic-contaminated soils. In this paper, the adsorption and desorption of arsenic onto different iron-containing materials including hematite, limonite, siderite, ilmenite, magnetite, Fe2O3, Fe3O4, and Fe-Mn binary oxide (FMBO) were studied in laboratory experiments. The mechanism of arsenic adsorption was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The results showed that arsenic adsorption is fitted by pseudo-second-order kinetics and the Langmuir isotherm model for almost all adsorbents, suggesting monolayer adsorption of arsenic onto the minerals. The sorption efficiency and capacity of arsenic by FMBO are much higher than those of other materials. Furthermore, limonite has high sorption efficiencies for both As(Ⅲ) and As(Ⅴ) among the natural iron-containing minerals, and their adsorption capacities are 3.96 mg·g-1 and 2.99 mg·g-1, respectively. The XRD results showed that natural limonite contains a large number of weak crystalline mineral components such as goethite, which can provide relatively abundant arsenic adsorption sites. Thus, limonite appears to be the most suitable natural mineral for arsenic adsorption.

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