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1.
Aging Clin Exp Res ; 36(1): 111, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38743351

RESUMO

BACKGROUND: Delirium is common among elderly patients in the intensive care unit (ICU) and is associated with prolonged hospitalization, increased healthcare costs, and increased risk of death. Understanding the potential risk factors and early prevention of delirium is critical to facilitate timely intervention that may reverse or mitigate the harmful consequences of delirium. AIM: To clarify the effects of pre-admission falls on ICU outcomes, primarily delirium, and secondarily pressure injuries and urinary tract infections. METHODS: The study relied on data sourced from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Statistical tests (Wilcoxon rank-sum or chi-squared) compared cohort characteristics. Logistic regression was employed to investigate the association between a history of falls and delirium, as well as secondary outcomes, while Kaplan-Meier survival curves were used to assess short-term survival in delirium and non-delirium patients. RESULTS: Study encompassed 22,547 participants. Delirium incidence was 40%, significantly higher in patients with a history of falls (54.4% vs. 34.5%, p < 0.001). Logistic regression, controlling for confounders, not only confirmed that a history of falls elevates the odds of delirium (OR: 2.11; 95% CI: 1.97-2.26; p < 0.001) but also showed it increases the incidence of urinary tract infections (OR:1.50; 95% CI:1.40-1.62; p < 0.001) and pressure injuries (OR:1.36; 95% CI:1.26-1.47; p < 0.001). Elderly delirium patients exhibited lower 30-, 180-, and 360-day survival rates than non-delirium counterparts (all p < 0.001). CONCLUSIONS: The study reveals that history of falls significantly heighten the risk of delirium and other adverse outcomes in elderly ICU patients, leading to decreased short-term survival rates. This emphasizes the critical need for early interventions and could inform future strategies to manage and prevent these conditions in ICU settings.


Assuntos
Acidentes por Quedas , Estado Terminal , Delírio , Unidades de Terapia Intensiva , Humanos , Delírio/epidemiologia , Idoso , Acidentes por Quedas/estatística & dados numéricos , Feminino , Masculino , Idoso de 80 Anos ou mais , Estudos de Coortes , Fatores de Risco , Hospitalização , Incidência , Infecções Urinárias/epidemiologia
2.
Chem Biodivers ; : e202401921, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39246262

RESUMO

Six previously unreported papulacandins, namely pestiorosins A-F (1-6), were isolated from the fermentation products of the fungus Pestalotiopsis rosea YNJ21 isolated from the fruitbody of Amanita exitialis. The structures of these compounds, along with a known compound called pestiocandin (7), were determined using MS, NMR data, and modified Mosher's method. All compounds exhibited significant antifungal activity against Candida albicans, with MIC values ranging from 0.06 to 2.00 µg/mL. In terms of cytotoxicity assays, compounds 3 and 6 demonstrated moderate inhibitory activity against human breast cancer MCF-7 cells with IC50 values of 24.50 and 16.83 µM, respectively. On the other hand, compound 7 displayed similar levels of inhibitory activity against mice microglial BV2 cells with an IC50 value of 24.51 µM.

3.
BMC Geriatr ; 23(1): 172, 2023 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-36973658

RESUMO

BACKGROUND: Frailty is the third most common complication of diabetes after macrovascular and microvascular complications. The aim of this study was to develop a validated risk prediction model for frailty in patients with diabetes. METHODS: The research used data from the China Health and Retirement Longitudinal Study (CHARLS), a dataset representative of the Chinese population. Twenty-five indicators, including socio-demographic variables, behavioral factors, health status, and mental health parameters, were analyzed in this study. The study cohort was randomly divided into a training set and a validation set at a ratio of 70 to 30%. LASSO regression analysis was used to screen the variables for the best predictors of the model based on a 10-fold cross-validation. The logistic regression model was applied to explore the associated factors of frailty in patients with diabetes. A nomogram was constructed to develop the prediction model. Calibration curves were applied to evaluate the accuracy of the nomogram model. The area under the receiver operating characteristic curve and decision curve analysis were conducted to assess predictive performance. RESULTS: One thousand four hundred thirty-six patients with diabetes from the CHARLS database collected in 2013 (n = 793) and 2015 (n = 643) were included in the final analysis. A total of 145 (10.9%) had frailty symptoms. Multivariate logistic regression analysis showed that marital status, activities of daily living, waist circumference, cognitive function, grip strength, social activity, and depression as predictors of frailty in people with diabetes. These factors were used to construct the nomogram model, which showed good concordance and accuracy. The AUC values of the predictive model and the internal validation set were 0.912 (95%CI 0.887-0.937) and 0.881 (95% CI 0.829-0.934). Hosmer-Lemeshow test values were P = 0.824 and P = 0.608 (both > 0.05). Calibration curves showed significant agreement between the nomogram model and actual observations. ROC and DCA indicated that the nomogram had a good predictive performance. CONCLUSIONS: Comprehensive nomogram constructed in this study was a promising and convenient tool to evaluate the risk of frailty in patients with diabetes, and contributed clinicians to screening the high-risk population.


Assuntos
Diabetes Mellitus , Fragilidade , Humanos , Atividades Cotidianas , Fragilidade/diagnóstico , Fragilidade/epidemiologia , Estudos Longitudinais , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia
4.
Chem Biodivers ; 20(9): e202300991, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37580280

RESUMO

A new polyaromatic metabolite, ent-herqueidiketal (1), and a new phenalenone derivative, epi-peniciherqueinone (2), along with twelve known compounds 3-14, were isolated from the fungus Penicillium herquei YNJ-35, a symbiotic fungus of Pulveroboletus brunneopunctatus collected from Nangunhe Nature Reserve, Yunnan Province, China. The structures of 1-14 and the absolute configurations of 1 and 2 were determined by their spectroscopic data or by their single-crystal X-ray diffraction analysis or optical rotation values. Compound 1 showed strong antibacterial activity against Staphylococcus aureus (ATCC 29213) with minimum inhibitory concentration (MIC) of 8 µg/mL. In the cytotoxicity assays, compound 1 showed weak inhibitory activity against breast cancer MCF-7 and mice microglial BV2 cells with half maximal inhibitory concentration (IC50 ) of 17.58 and 29.56 µM; compound 14 showed stronger cytotoxicity against BV2 and MCF-7 cells with IC50 values of 6.57 and 10.26 µM.


Assuntos
Agaricales , Penicillium , Animais , Camundongos , Estrutura Molecular , China , Penicillium/química
5.
Geriatr Nurs ; 49: 81-88, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36446149

RESUMO

Aging has gradually accelerated in China, and achieving successful aging of older adults has become a public health concern. Intergenerational support is crucial for Chinese older adults in later life due to the culture of filial piety. However, the association between successful aging and intergenerational support remains poorly understood in China. This study aimed to examine the association between patterns of intergenerational support and successful aging of older adults in China. The present study is a secondary analysis of data obtained from the follow-up survey of the China Health and Retirement Longitudinal Study 2018. Data were analyzed using descriptive statistics and logistic regressions. Bidirectional intergenerational support was associated with successful aging in the participants. In addition, there was an association between different intergenerational financial, caring, and emotional support patterns and elements of successful aging.


Assuntos
Envelhecimento , Aposentadoria , Humanos , Idoso , Estudos Longitudinais , Inquéritos e Questionários , China , Relação entre Gerações
6.
Int J Biol Macromol ; 281(Pt 2): 136209, 2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39383899

RESUMO

Platelet-rich plasma (PRP) has been recognized as an effective therapy in regenerative medicine and surgery, which can reduce the risk of antibiotic abuse and promote the healing of infected wounds. Recent advances in PRP-based treatments have focused on the controlled release of growth factors in PRP with biocompatible hydrogels and antimicrobial promotion by introducing hydrogel components or antibiotics, while the inherent antimicrobial activity of PRP is mostly neglected or sacrificed. Here, we demonstrate the combination of an antimicrobial polysaccharide, carboxymethyl chitosan, and PRP to construct an antimicrobial hydrogel via dynamic bonding with oxidized chondroitin sulfate. Significant inhibitory effects against Staphylococcus aureus and Escherichia coli (95 % of inhibition rate) are achieved through the synergistic contributions of the polysaccharide and PRP. Additionally, the resulting hydrogel promotes the migration of NIH-3T3 fibroblasts and collagen deposition by approximately 1.7 and 1.8 times, respectively, thereby accelerating the healing process of infected wounds. This work may bring new perspectives for potent applications of PRP-based hydrogel dressings for antibiotic-free management of infected wounds.

7.
Huan Jing Ke Xue ; 45(3): 1644-1654, 2024 Mar 08.
Artigo em Zh | MEDLINE | ID: mdl-38471876

RESUMO

In order to explore the effects of continuous annual crop rotation and fallow on aggregate stability and organic carbon content in red soil, the red soil in sloping farmland was taken as the research object, and the water-stable aggregates and organic carbon content were determined using the wet sieve method and potassium dichromate-concentrated sulfuric acid external heating method, respectively. The changes in soil aggregate stability and organic carbon content under the four treatments of maize-vetch-maize rotation (M-V-M), maize-pea-maize rotation (M-P-M), maize-fallow-maize (M-F-M), and annual fallow (F-F-F) from 2020 to 2022 and the relationships between them were analyzed. The results showed that in 2021 and 2022, the contents of > 2 mm aggregates treated with F-F-F, M-V-M, and M-P-M were significantly increased by 67.01%-100.92%, 29.71%-33.67%, and 29.68%-38.07%, respectively, compared with that treated with M-F-M. In 2021 and 2022, the stability parameters of F-F-F and M-V-M were significantly higher than those of M-F-M (P < 0.05). The content of > 2 mm aggregates, geometric mean diameter (GMD), and mean weight diameter (MWD) under the M-V-M treatment and R0.25 (> 0.25 mm aggregate contents), MWD and > 2 mm aggregate contents under the F-F-F treatment increased with the increase in fallow years, whereas the content of 1-2 mm and < 0.25 mm under the F-F-F treatment decreased with the increase in fallow years. Both green manure rotation and fallow treatment could increase the SOC content, and the SOC content of F-F-F and M-V-M treatment increased with the extension in age. Correlation analysis showed that SOC content was significantly positively correlated with R0.25 and GMD under all treatments. R0.25 and GMD under the F-F-F treatment and GMD and MWD under M-V-M were significantly positively correlated with SOC content. The results showed that continuous annual crop rotation and fallow was beneficial to improve the content of soil macro-aggregates, aggregate stability, and SOC content, which could provide theoretical basis for the implementation of reasonable continuous annual crop rotation and fallow patterns and soil erosion control in red soil areas of sloping farmland in southern China.

8.
Food Chem X ; 22: 101272, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38550891

RESUMO

Moringa oleifera Lam. leaves are a new raw food material rich in polysaccharides. These polysaccharides exhibit various biological properties, including antioxidant, hypoglycemic and immunoregulatory effects. However, the use of Moringa oleifera Lam. leaves polysaccharides (MOLP) may be limited by their large molecular weight (MW) and presence of numerous impurities, such as pigments. Research has indicated that degraded polysaccharides usually exhibit high biological activity because of changes in physical structure and chemical properties. In this study, we focused on the extraction of a degraded-modified fraction from MOLP using the Ultraviolet/ Hydrogen peroxide (UV/H2O2) method. Specifically, the physicochemical properties and glycosidic bond composition of a particular fraction (UV/H2O2 degraded Moringa oleifera Lam. leaves polysaccharides in 3 h called DMOLP-3) were investigated. In addition, in vitro simulated digestion experiments showed that DMOLP-3 was only partially degraded during gastrointestinal digestion, indicating that DMOLP-3 can be utilised by gut microorganisms. Furthermore, the prebiotic properties of MOLP and DMOLP-3 was studied using an in vitro faecal fermentation model. The results indicated that compared with MOLP, DMOLP-3 led to a decrease in both the colour and MW of the polysaccharides. In addition, this model exhibited enhanced solubility and antioxidant capabilities while also influencing the surface morphology. Moreover, DMOLP-3 can facilitate the proliferation of advantageous microorganisms and enhance the synthesis of short-chain fatty acids (SCFAs). These results provide valuable insights into the utilization of bioactive components in Moringa oleifera Lam. leaves for the intestinal health.

9.
Perioper Med (Lond) ; 13(1): 41, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755693

RESUMO

BACKGROUND: Postoperative delirium is a common complication in older patients, with poor long-term outcomes. This study aimed to investigate risk factors and develop a predictive model for postoperative delirium in older patients after major abdominal surgery. METHODS: This study retrospectively recruited 7577 patients aged ≥ 65 years who underwent major abdominal surgery between January 2014 and December 2018 in a single hospital in Beijing, China. Patients were divided into a training cohort (n = 5303) and a validation cohort (n = 2224) for univariate and multivariate logistic regression analyses and to build a nomogram. Data were collected for 43 perioperative variables, including demographics, medical history, preoperative laboratory results, imaging, and anesthesia information. RESULTS: Age, chronic obstructive pulmonary disease, white blood cell count, glucose, total protein, creatinine, emergency surgery, and anesthesia time were associated with postoperative delirium in multivariate analysis. We developed a nomogram based on the above 8 variables. The nomogram achieved areas under the curve of 0.731 and 0.735 for the training and validation cohorts, respectively. The discriminatory ability of the nomogram was further assessed by dividing the cases into three risk groups (low-risk, nomogram score < 175; medium-risk, nomogram score 175~199; high-risk, nomogram score > 199; P < 0.001). Decision curve analysis revealed that the nomogram provided a good net clinical benefit. CONCLUSIONS: We developed a nomogram that could predict postoperative delirium with high accuracy and stability in older patients after major abdominal surgery.

10.
Carbohydr Polym ; 315: 120973, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37230636

RESUMO

Diabetes is generally accompanied by difficult-to-heal wounds, which often lead to permanent disability and even death of patients. Because of the abundance of a variety of growth factors, platelet rich plasma (PRP) has been proven to have great clinical potential for diabetic wound treatment. However, how to suppress the explosive release of its active components while realizing adaptability to different wounds remains important for PRP therapy. Here, an injectable, self-healing, and non-specific tissue-adhesive hydrogel formed by oxidized chondroitin sulfate and carboxymethyl chitosan was designed as an encapsulation and delivery platform for PRP. With a dynamic cross-linking structural design, the hydrogel can meet the clinical demands of irregular wounds with controllable gelation and viscoelasticity. Inhibition of PRP enzymolysis as well as sustained release of its growth factors is realized with the hydrogel, enhancing cell proliferation and migration in vitro. Notably, greatly accelerated healing of full thickness wounds of diabetic skins is enabled by promoting the formation of granulation tissues, collagen deposition and angiogenesis as well as reducing inflammation in vivo. This self-healing and extracellular matrix-mimicking hydrogel provides powerful assistance to PRP therapy, enabling its promising applications for the repair and regeneration of diabetic wounds.


Assuntos
Diabetes Mellitus , Plasma Rico em Plaquetas , Humanos , Hidrogéis/farmacologia , Hidrogéis/química , Cicatrização , Pele , Peptídeos e Proteínas de Sinalização Intercelular , Plasma Rico em Plaquetas/química
11.
Huan Jing Ke Xue ; 44(9): 5154-5163, 2023 Sep 08.
Artigo em Zh | MEDLINE | ID: mdl-37699833

RESUMO

To investigate the effects of crop rotation and fallow on the community composition of arbuscular mycorrhizal fungi (AMF) and the stability of soil aggregates, AMF community and aggregates were measured using Illumina MiSeq high-throughput sequencing and wet screening methods in red soil of sloping farmland. The AMF community and its relationship with soil factors and aggregate stability were studied under the four treatments of vetch rotation corn (V-C), pea rotation corn (P-C), winter fallow corn (F-C), and annual fallow (F-F). The results showed that the aggregate content of >2 mm, R0.25, and MWD in the F-F, V-C, and P-C treatments were significantly higher than those in F-C (P<0.05), and the aggregate content of <0.25 mm was significantly lower than that of F-C (P<0.05). The ACE, Chao1, and Shannon indexes of the F-F treatment were 29.56%, 35.78%, and 45.55% higher than those of the F-C treatment, respectively. Glomus was the dominant genus of AMF communities under all treatments, whereas Scutellospora showed a significant difference among the treatments (P<0.05). PCoA analysis showed that PC1 and PC2 together explained 29.99% and 22.40% of the difference in the AMF community composition, respectively. The correlation analysis showed that there was a significant negative correlation between Scutellospora and alkaline nitrogen (AN) and organic matter (SOM) (P<0.05), a significant positive correlation between Scutellospora and available potassium (AK) (P<0.05), and a significant positive correlation between Glomus and alkaline nitrogen (P<0.05). RDA analysis showed that AMF diversity (Shannon index) and Scutellospora were significantly and positively correlated with aggregate content >2 mm and 2-1 mm, respectively (P<0.05). Therefore, annual fallow and vetch rotation corn were conducive to improving the stability of soil aggregates and changing the composition of the AMF community. The research results provide a theoretical basis and reference for the annual rotation system to improve soil quality and implement a reasonable crop rotation and fallow pattern in southern China.


Assuntos
Glomeromycota , Micorrizas , Nitrogênio , Solo , Zea mays , Produção Agrícola
12.
Food Chem X ; 14: 100322, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35571331

RESUMO

Moringa oleifera Lam. (M. oleifera Lam) is a perennial tropical deciduous tree that belongs to the Moringaceae family. Polysaccharides are one of the major bioactive compounds in M. oleifera Lam and show immunomodulatory, anticancer, antioxidant, intestinal health protection and antidiabetic activities. At present, the structure and functional activities of M. oleifera Lam polysaccharides (MOPs) have been widespread, but the research data are relatively scattered. Moreover, the relationship between the structure and biological activities of MOPs has not been summarized. In this review, the current research on the extraction, purification, structural characteristics and biological activities of polysaccharides from different sources of M. oleifera Lam were summarized, and the structural characteristics of purified polysaccharides were focused on this review. Meanwhile, the biological activities of MOPs were introduced, and some molecular mechanisms were listed. In addition, the relationship between the structure and biological activities of MOPs was discussed. Furthermore, new perspectives and some future research of M. oleifera Lam polysaccharides were proposed in this review.

13.
Front Nutr ; 9: 824525, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35273989

RESUMO

Fatigue is a common physiological phenomenon caused by many complicated factors. Excessive fatigue will lead to a series of uncomfortable reactions and damage body health. Panax notoginseng leaves (PNL) is a new resource food that good for soothing nerves, nourishing the heart, and strengthening the spleen. Microbial fermentation could increase the content of bio-ingredients and produce new active ingredients. However, the effect of fermented P. notoginseng leaves (FPNL) on antifatigue and the molecular mechanisms remain to be elucidated. Thus, in this study, we evaluated the antifatigue effect of co-fermented P. notoginseng leaves by Saccharomyces cerevisiae and Bacillus subtilis in-vitro and in-vivo, and its mechanism was further elucidated. The results showed that FPNL exhibited higher saponins, organic phenolic acids content, and antioxidant activity than PNL. FPNL improved ISO-induced H9c2 myocardial cell damage by alleviating apoptosis (modulating Bax and Bcl-2 protein expression) and reducing antioxidant activity in-vitro. Moreover, in-vivo experiment showed that FPNL significantly prolonged the weight-loading swimming time of mice. After gavaged FPNL, the levels of liver glycogen (LG) and serum lactate dehydrogenase (LDH) activity were increased in mice. In contrast, the levels of blood urea nitrogen (BUN), lactate acid, and malondialdehyde (MDA) were decreased. In summary, our results indicated that FPNL showed a good antifatigue effect in-vivo and in-vitro.

14.
Front Pharmacol ; 12: 639256, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33953676

RESUMO

Astragalin is a flavonoid found in a variety of natural plants. It has anti-inflammatory, anti-oxidant effects and has inhibited effects against several malignant tumor cell types. However, its effects on colon cancer and the molecular mechanisms have remained to be elucidated. In this study, we evaluated the inhibitory effect of astragalin on proliferation and migration of human colon cancer HCT116 cells in vitro and in vivo. Furthermore, we elucidated the mechanism of these effects. The results showed that astragalin significantly inhibited the proliferation and diffusion of HCT116 cells by induced apoptosis (by modulation of Bax, Bcl-2, P53, caspase-3, caspase 6, caspase 7, caspase 8, caspase 9 protein express) and cell cycle arrest (by modulation of Cyclin D1, Cyclin E, P21, P27, CDK2, CDK4 protein express). Moreover, astragalin suppressed HCT116 cell migration by inhibiting the expression of matrix metalloproteinases (MMP-2, MMP-9). In addition, astragalin significantly downregulated the expression of key proteins in the NF-κB signaling pathway and inhibited the transcriptional activity of NF-κB P65 stimulated with inflammatory cytokines TNF-α, thereby inhibiting the growth of colon cancer cells in vitro. Our further investigations unveiled astragalin gavage significantly reduced the proliferation of colon cancer xenograft in nude mice, in vivo experiments showed that tumor growth was related to decreased expression of apoptotic proteins in tumor tissues and decreased activity of the NF-κB signaling pathway. In summary, our results indicated that astragalin inhibits the proliferation and growth of colon cancer cells in vivo and in vitro via the NF-κB pathway. Therefore, astragalin maybe become a potential plant-derived antitumor drug for colon cancer.

15.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(6): 704-707, 2020 Dec 01.
Artigo em Zh | MEDLINE | ID: mdl-33377351

RESUMO

Mesenchymal stem cells (MSCs), which have the potential of self-replication and differentiation, are a very valuable cell source for stem cell-based medical therapy. Their application has opened up a new way for disease research. Although MSCs can maintain cell stemness through self-renewal, with the prolongation of cell passage and culture time, the stemness of MSCs gradually decays, and the cell aging and differentiation potential decreases gradually. Autophagy is a highly conserved cytological process that degrades the modified, excess, and deleterious cytoplasmic components in autophagosomes, which are then degraded by fusion with lysosomes. As the main intracellular degradation and recycling pathway, autophagy plays an active role in maintaining cell homeostasis, self-renewal and pluripotency. In this paper, the role of autophagy in self-renewal and maintenance of multidirectional differentiation potential of MSCs was reviewed, which laid a theoretical foundation and practical basis for the research and application of MSCs.


Assuntos
Células-Tronco Mesenquimais , Autofagia , Diferenciação Celular , Homeostase
16.
Yi Chuan ; 28(2): 159-64, 2006 Feb.
Artigo em Zh | MEDLINE | ID: mdl-16520310

RESUMO

Different breeds of pigs varied in traits of meat quality, especially between local abroad varieties. Intramuscular fat content (IMF) and back fat thickness (BF) have extra difference between Chinese breeds and foreign breeds. We have known that polymorphism of H-FABP, MC4R and ADD1 gene associated relation with IMF or BF in recent research. The Meishan, Sutai and Duroc x Landrace x Yorkshair become experimental animal in this research. Result show three breeds have different IMF and BF because different distributions of polymorphism three genes. Meishan has particular genetic background, so it should be protected. The results of associated analysis show that the polymorphism of three genes was associated traits of IMF and BF, polymorphism of MC4R gene was not associated traits BF. The molecular marker can apply to pig breeding by molecular marker-assisted selection (MAS).


Assuntos
Proteínas de Ligação a Ácido Graxo/genética , Polimorfismo Genético/genética , Receptor Tipo 4 de Melanocortina/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Animais , Composição Corporal/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição/genética , Polimorfismo Conformacional de Fita Simples/genética
17.
Ying Yong Sheng Tai Xue Bao ; 23(3): 751-7, 2012 Mar.
Artigo em Zh | MEDLINE | ID: mdl-22720621

RESUMO

Farmland soil carbon and nitrogen contents under intensive agricultural production are the important indices for the assessment of the soil fertility sustainability. This paper measured the soil pH, electrical conductivity (EC), organic carbon (SOC), total nitrogen (TN), and delta13C and delta15N isotope abundances of four types of farmland, i.e., conventional rice-broad bean rotation field, open vegetable field, 3-year plastic covered greenhouse field, and > 10-year plastic covered greenhouse field, aimed to understand the effects of intensive agricultural production degree on soil properties. In the open vegetable field, 3-year plastic covered greenhouse field, and > 10-year plastic covered greenhouse field, the soil (0-20 cm) pH decreased by 1.1, 0.8, and 0.7, and the soil EC was 4.2, 4.9, and 5.2 folds of that in conventional rice-broad bean rotation field, respectively. With the increasing year of plastic covered greenhouse production, the soil SOC and TN contents decreased after an initial increase. Comparing with those under rice-broad bean rotation, the SOC content in 0-20, 20-40, 40-60, 60-80 and 80-100 cm soil layers in >10-year plastic covered greenhouse decreased by 54%, 46%, 60%, 63%, and 59%, and the TN content decreased by 53%, 53%, 71%, 82%, and 85%, respectively. Intensive agricultural production degree had significant effects on the soil SOC and TN contents and delta13C and delta15N abundances. The delta13C abundance was significantly negatively correlated with the soil SOC, suggesting that the soil delta13C abundance could be regarded as an index for the assessment of carbon cycle in farmland soils under effects of human activities.


Assuntos
Carbono/análise , Nitrogênio/análise , Oryza/crescimento & desenvolvimento , Solo/análise , Verduras/crescimento & desenvolvimento , Agricultura/métodos , Isótopos de Carbono/análise , Ambiente Controlado , Isótopos de Nitrogênio/análise , Triticum/crescimento & desenvolvimento
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