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1.
J Phys Condens Matter ; 36(48)2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39191269

RESUMEN

This work uses first-principles calculations to investigate the phase stability, thermophysical and mechanical properties of refractory high entropy alloys (RHEAs) at finite temperatures. On the basis of plane wave quasi-potential and density functional theory, construct the structure model of a solid solution. The TiMoNbX (X = Cr, Ta, Cr and Ta) RHEAs have been determined to preserve a single body-centered cubic solid solution structure by calculations and the equilibrium lattice parameters and elastic modulus are consistent with experimental data obtained by laser cladding, which is combined with TC4 (Ti-6Al-4V) substrate. Using the quasi-harmonic Debye-Grüneisen model, the thermophysical characteristics of three RHEAs are investigated. The Voigt-Reuss-Hill scheme is used for calculating the Young's modulus (E), bulk modulus (B), shear modulus (G), and Poisson's ratio (ν), which indicates that all three RHEAs are ductile materials. Additionally, the modulus and hardness of materials decrease as temperature rises, whereas the properties of TiMoNbX RHEAs are predicted, as the nanoindentation hardness values at room temperature are comparable to, and slightly higher than the calculated values.

2.
J Neuroimmunol ; 394: 578409, 2024 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-39088909

RESUMEN

BACKGROUND: The aim of this study was to explore the causal association between immune cells and VaD based on a two-sample bidirectional Mendelian randomization study. METHODS: Bidirectional two-sample MR analyses based on pooled datasets from publicly available genome-wide association studies were performed using inverse variance weighted (IVW), weighted median (WE), and MR-Egger regressions to evaluate the causal relationships between immune cells and vascular dementia. Heterogeneity was assessed using Cochran's Q statistic. The reliability of the MR analysis results was verified by using the MR-PRESSO method for outlier detection, the MR-Egger method for horizontal multivariate analysis, and the leave-one-out method for sensitivity analysis. RESULTS: Specifically, 27 immunophenotypes were associated with VaD pathogenesis, including Sw mem %lymphocyte (P = 0.043), CD38 on CD20- (P = 0.039), CD11c+ monocyte AC (P = 0.024), DC AC (P = 0.002), CCR2 on CD62L+ myeloid DC (P = 0.039), Resting Treg %CD4 (P = 0.042), Activated & resting Treg %CD4+ (P = 0.038), CD28+ CD45RA- CD8br %CD8br (P = 0.047), NK %CD3- lymphocyte (P = 0.042), CD45 on B cell (P = 0.029), FSC-A on NKT (P = 0.033), CD45 on CD33br HLA DR+ CD14- (P = 0.039) were significantly correlated with increased VaD risk. Additionally, four immune phenotypes, namely, CD19 on CD20-, Resting Treg %CD4, Activated & resting Treg %CD4+, and CD11c+ monocyte AC, showed bidirectional effects on VaD. CONCLUSIONS: MR analysis revealed potential causal relationships between certain immune cells and VaD. Our preliminary exploration through immune cell infiltration analysis highlights the significant value of immune cells in VaD. Therefore, this study may provide a new perspective for the prevention and treatment of VaD.


Asunto(s)
Demencia Vascular , Estudio de Asociación del Genoma Completo , Análisis de la Aleatorización Mendeliana , Humanos , Análisis de la Aleatorización Mendeliana/métodos , Demencia Vascular/genética , Demencia Vascular/inmunología
3.
Sci Rep ; 14(1): 11947, 2024 05 25.
Artículo en Inglés | MEDLINE | ID: mdl-38789486

RESUMEN

A research model combining a disease and syndrome can provide new ideas for the treatment of ischemic stroke. In the field of traditional Chinese medicine, blood stasis and toxin (BST) syndrome is considered an important syndrome seen in patients with ischemic stroke (IS). However, the biological basis of IS-BST syndrome is currently not well understood. Therefore, this study aimed to explore the biological mechanism of IS-BST syndrome. This study is divided into two parts: (1) establishment of an animal model of ischemic stroke disease and an animal model of BST syndrome in ischemic stroke; (2) use of omics methods to identify differentially expressed genes and metabolites in the models. We used middle cerebral artery occlusion (MCAO) surgery to establish the disease model, and utilized carrageenan combined with active dry yeast and MCAO surgery to construct the IS-BST syndrome model. Next, we used transcriptomics and metabolomics methods to explore the differential genes and metabolites in the disease model and IS-BST syndrome model. It is found that the IS-BST syndrome model exhibited more prominent characteristics of IS disease and syndrome features. Both the disease model and the IS-BST syndrome model share some common biological processes, such as thrombus formation, inflammatory response, purine metabolism, sphingolipid metabolism, and so on. Results of the "gene-metabolite" network revealed that the IS-BST syndrome model exhibited more pronounced features of complement-coagulation cascade reactions and amino acid metabolism disorders. Additionally, the "F2 (thrombin)-NMDAR/glutamate" pathway was coupled with the formation process of the blood stasis and toxin syndrome. This study reveals the intricate mechanism of IS-BST syndrome, offering a successful model for investigating the combination of disease and syndrome.


Asunto(s)
Modelos Animales de Enfermedad , Accidente Cerebrovascular Isquémico , Medicina Tradicional China , Metabolómica , Transcriptoma , Animales , Metabolómica/métodos , Accidente Cerebrovascular Isquémico/metabolismo , Accidente Cerebrovascular Isquémico/genética , Medicina Tradicional China/métodos , Masculino , Redes Reguladoras de Genes , Ratas , Perfilación de la Expresión Génica , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/genética , Síndrome , Ratas Sprague-Dawley
4.
Sci Rep ; 13(1): 21947, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-38081961

RESUMEN

Environmental pollution and energy shortages have brought about an increased focus on new energy vehicles. Hydrogen fuel cell vehicles (HFCVs) have experienced rapid development due to the potential to alleviate energy pressures and reduce pollution emissions. Near zero-carbon emissions offer a promising avenue for promoting sustainable transportation development. To evaluate the impact of HFCVs on the transportation environment, this paper investigates the problem of sustainable transportation network design including HFCVs. Specifically, the problem is formulated as a bi-level multi-objective programming problem, with the upper level aimed at determining the optimal network design scheme considering multiple objectives, while the lower level addresses the mixed traffic flow that comprises both HFCVs and fuel vehicles. To solve the multi-objective sustainable network design problem, an integrated solution framework that combines the particle swarm optimization (PSO) algorithm with the Frank-Wolfe algorithm (FW) is developed. Specifically, the PSO algorithm is utilized to solve the upper-level model and identify the optimal network design schemes, while FW algorithm is adopted to handle mixed traffic flow assignments. Finally, the proposed model and algorithm are implemented in two numerical experiment to demonstrate their effectiveness and efficiency.

5.
BMJ Open ; 13(11): e074871, 2023 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-38035742

RESUMEN

INTRODUCTION: Tension-type headache (TTH) is the most prevalent headache disorder worldwide. Although current treatments for TTH are beneficial, they are not without adverse effects. Chaixiong Qiwei granule (CXQW) is an experienced prescription medicine for TTH management. This study will evaluate the efficacy and safety of CXQW for the treatment of TTH. METHODS AND ANALYSIS: This study will be a multicentre, randomised, double-blind, placebo-controlled trial. A total of 148 eligible participants will be divided into the intervention (CXQW treatment) and control (placebo treatment) groups. The primary outcome will be the reduction in the number of headache days (headache-days reduction) within 9-12 weeks after randomisation, while secondary outcomes will include the number of headache days, headache intensity, responder rate, drug consumption for acute treatment, quality of life and symptoms related to traditional Chinese medicine use based on a symptom-observation table. This protocol describes the design of the randomised controlled trial. ETHICS AND DISSEMINATION: The study design was approved by the Institutional Review Board of Human Research at Xiyuan Hospital, China Academy of Chinese Medical Sciences (No. 2020XLA030-2). TRIAL REGISTRATION NUMBER: ChiCTR2100042514.


Asunto(s)
Cefalea de Tipo Tensional , Humanos , Cefalea de Tipo Tensional/tratamiento farmacológico , Calidad de Vida , Método Doble Ciego , Medicina Tradicional China , Cefalea/tratamiento farmacológico , Resultado del Tratamiento , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Multicéntricos como Asunto
6.
Sci Rep ; 13(1): 12322, 2023 07 29.
Artículo en Inglés | MEDLINE | ID: mdl-37516796

RESUMEN

Nowadays, global public health crises are occurring more frequently, and accurate prediction of these diseases can reduce the burden on the healthcare system. Taking COVID-19 as an example, accurate prediction of infection can assist experts in effectively allocating medical resources and diagnosing diseases. Currently, scholars worldwide use single model approaches or epidemiology models more often to predict the outbreak trend of COVID-19, resulting in poor prediction accuracy. Although a few studies have employed ensemble models, there is still room for improvement in their performance. In addition, there are only a few models that use the laboratory results of patients to predict COVID-19 infection. To address these issues, research efforts should focus on improving disease prediction performance and expanding the use of medical disease prediction models. In this paper, we propose an innovative deep learning model Whale Optimization Convolutional Neural Networks (CNN), Long-Short Term Memory (LSTM) and Artificial Neural Network (ANN) called WOCLSA which incorporates three models ANN, CNN and LSTM. The WOCLSA model utilizes the Whale Optimization Algorithm to optimize the neuron number, dropout and batch size parameters in the integrated model of ANN, CNN and LSTM, thereby finding the global optimal solution parameters. WOCLSA employs 18 patient indicators as predictors, and compares its results with three other ensemble deep learning models. All models were validated with train-test split approaches. We evaluate and compare our proposed model and other models using accuracy, F1 score, recall, AUC and precision metrics. Through many studies and tests, our results show that our prediction models can identify patients with COVID-19 infection at the AUC of 91%, 91%, and 93% respectively. Other prediction results achieve a respectable accuracy of 92.82%, 92.79%, and 91.66% respectively, f1-score of 93.41%, 92.79%, and 92.33% respectively, precision of 93.41%, 92.79%, and 92.33% respectively, recall of 93.41%, 92.79%, and 92.33% respectively. All of these exceed 91%, surpassing those of comparable models. The execution time of WOCLSA is also an advantage. Therefore, the WOCLSA ensemble model can be used to assist in verifying laboratory research results and predict and to judge various diseases in public health events.


Asunto(s)
COVID-19 , Aprendizaje Profundo , Animales , COVID-19/diagnóstico , Algoritmos , Benchmarking , Cetáceos
7.
iScience ; 26(5): 106641, 2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37192976

RESUMEN

Severe arable land loss and ecological problems raise attention to protect/develop land for food and ecology demand. Spatial conflict appears in front of multidemand for urbanization, food, and ecology. Our study took China as an example and explicitly outlined spatial preference of urbanization, food, and ecology. From the aspect of land amount, there are enough lands to support multidemand with a surplus of agriculture land of 45.5 × 106 ha. However, spatial conflict widely appears among the multidemands. We tested the impacts of different priorities on urban pattern, crop yield, and ecology and found the priority of food > ecology > urbanization gave the best outcome. Our results verified the importance of including priority of land multidemand to avoid confusion and increase efficiency in the implementation of land policies.

8.
Materials (Basel) ; 16(10)2023 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-37241489

RESUMEN

TiMoNbX (X = Cr, Ta, Zr) RHEA coatings were fabricated on TC4 titanium alloy substrate using laser cladding technology. The microstructure and corrosion resistance of the RHEA were studied by XRD, SEM and an electrochemical workstation. The results show that the TiMoNb series RHEA coating was composed of a columnar dendrite (BCC) phase, a rod-like second phase, a needle-like structure and equiaxed dendrite, but the TiMoNbZr RHEA coating showed high-density defects, similar to those in TC4 titanium alloy, which were composed of small non-equiaxed dendrites and lamellar α'(Ti). In the 3.5% NaCl solution, compared with TC4 titanium alloy, the RHEA had a lower corrosion sensitivity and fewer corrosion sites, showing better corrosion resistance. The corrosion resistance of the RHEA ranged from strong to weak in this order: TiMoNbCr, TiMoNbZr, TiMoNbTa and TC4. The reason is that the electronegativity of different elements is different, and the speeds of the formation of the passivation film were very different. In addition, the positions of pores appearing in the laser cladding process also affected the corrosion resistance.

9.
Water Res ; 238: 120005, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37148691

RESUMEN

Global warming is expected to increase the atmospheric evaporative demand and make more surface water for evapotranspiration, aggerating water sources' social and ecological shortage. Pan evaporation, as a routine observation worldwide, is an excellent metric to indicate the response of terrestrial evaporation to global warming. However, several non-climatic effects, such as instrument upgrades, have destroyed the homogenization of pan evaporation and limited its applications. In China, 2400s meteorological stations have observed daily pan evaporation since 1951. The observed records became discontinuous and inconsistent due to the instrument upgrade from micro-pan D20 to large-pan E601. Here, combining the Penpan model (PM) and random forest model (RFM), we developed a hybrid model to assimilate different types of pan evaporation into a consistent dataset. Based on the cross-validation test, on a daily scale, the hybrid model has a lower bias (RMSE=0.41 mm day-1) and better stability (NSE=0.94) than the two sub-models and the conversion coefficient method. Finally, we produced a homogenized daily dataset of E601 across China from 1961 to 2018. Based on this dataset, we analyzed the long-term trend of pan evaporation. Pan evaporation showed a -1.23±0.57 mm a-2 downward trend from 1961-1993, primarily caused by decreased pan evaporation in warm seasons over North China. After 1993, the pan evaporation in South China increased significantly, resulting in a 1.83±0.87 mm a-2 upward trend across China. With better homogeneity and higher temporal resolution, the new dataset is expected to promote drought monitoring, hydrological modeling, and water resources management. Free access to the dataset can be found at https://figshare.com/s/0cdbd6b1dbf1e22d757e.


Asunto(s)
Calentamiento Global , Agua , China , Estaciones del Año , Hidrología
10.
Front Neurosci ; 17: 1123817, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36937659

RESUMEN

Post-stroke cognitive impairment, is a major complication of stroke, characterized by cognitive dysfunction, which directly affects the quality of life. Post-stroke cognitive impairment highlights the causal relationship between stroke and cognitive impairment. The pathological damage of stroke, including the increased release of excitatory amino acids, oxidative stress, inflammatory responses, apoptosis, changed neurotrophic factor levels and gene expression, influence synaptic plasticity. Synaptic plasticity refers to the activity-dependent changes in the strength of synaptic connections and efficiency of synaptic transmission at pre-existing synapses and can be divided into structural synaptic plasticity and functional synaptic plasticity. Changes in synaptic plasticity have been proven to play important roles in the occurrence and treatment of post-stroke cognitive impairment. Evidence has indicated that Chinese herbal drugs have effect of treating post-stroke cognitive impairment. In this review, we overview the influence of pathological damage of stroke on synaptic plasticity, analyze the changes of synaptic plasticity in post-stroke cognitive impairment, and summarize the commonly used Chinese herbal drugs whose active ingredient or extracts can regulate synaptic plasticity. This review will summarize the relationship between post-stroke cognitive impairment and synaptic plasticity, provide new ideas for future exploration of the mechanism of post-stroke cognitive impairment, compile evidence of applying Chinese herbal drugs to treat post-stroke cognitive impairment and lay a foundation for the development of novel formulas for treating post-stroke cognitive impairment.

11.
Front Neurol ; 13: 1005819, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36313493

RESUMEN

Background: Acupuncture is a proven technique of traditional Chinese medicine (TCM) for ischemic stroke. The purpose of this overview was to summarize and evaluate the evidence from current systematic reviews (SRs) of acupuncture for early recovery after acute ischemic stroke (AIS). Methods: We performed a comprehensive search for SRs of acupuncture for AIS in seven electronic databases up to May 23, 2022. Two reviewers independently selected SRs, extracted data, evaluated the methodological quality using the Assessment of Multiple Systematic Reviews 2 (AMSTAR 2), and rated evidence certainty using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Results: Seven SRs were included. The overall methodological quality of SRs was critically low. As for GRADE, 3 outcomes had moderate-quality evidence, 14 had low-quality evidence, and 12 had very low-quality evidence. Moderate-quality evidence demonstrated that initiating acupuncture therapies within 30 days of AIS onset significantly improves neurological function and the total effective rate of patients. Low-quality evidence showed that for patients within 2 weeks of AIS onset Xingnao Kaiqiao acupuncture (XNKQ Ac) could reduce disability rate and might reduce mortality. Regarding the safety of acupuncture therapies, low-quality evidence showed that there was no difference in the incidence of adverse reactions between the 2 groups, and very-low quality evidence showed that acupuncture did not promote hemorrhagic conversion. Conclusions: In the acute and early recovery phases after AIS onset, acupuncture is a promising therapeutic strategy to improve the curative effect of current treatments, especially in the recovery of neurological function. Patients in the acute phase might receive XNKQ Ac, and patients in the early recovery phase might receive EA1, CA, or SA. However, considering the current certainty of evidence, a solid recommendation warrants further exploration.Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022335426.

12.
J Environ Manage ; 289: 112492, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33819650

RESUMEN

Urbanization is an inevitable trend associated with social development that occurs preferentially in plain areas. Ecosystem services (ES) refer to the various benefits that human beings obtain from ecosystems. Competing priorities of economic development and ecological protection lead to conflicts in land use under conditions of urbanization, the root cause of which is an imbalance in the ES supply and demand. Whereas existing studies have mainly focused on the decline of ES supply capacities, an exploration of the extent to which the supply and demand of ES are matched and of their changing trends would be instructive and have practical implications. In this study, we examined changes in the temporal and spatial characteristics of the relationship between ES supply and demand in the Baiyangdian Basin in the North China Plain. We found that ES supply and demand were spatially distinctive. ES supply areas were concentrated in the western mountainous region, whereas ES demand areas were predominantly located in the eastern plain area. The main sources of ES surplus in the study area were woodland and grassland in mountainous areas, comprising 12% of the study region. Strict protection on these lands during the period 1980-2015 ensured a consistently high level of ES supply. In recent years, urbanization has been a major driver of increasing ES demand and decreasing ES surplus and is projected to accentuate the trend of declining ES surplus in the future. However, current policies remain focused on the protection of forests and grassland that predominate in mountainous areas, where urban expansion poses a lower threat compared with plain areas. We therefore recommend a policy emphasis on sustainable urban planning to mitigate ES degradation.


Asunto(s)
Ecosistema , Urbanización , China , Conservación de los Recursos Naturales , Bosques , Humanos
13.
Cell Mol Biol (Noisy-le-grand) ; 66(5): 105-110, 2020 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-33040822

RESUMEN

Ankylosing spondylitis (AS) is a chronic rheumatic disease that mainly affects the spinal joints (vertebrae). Spondylitis means inflammation of the spine, and ankylosing spondylitis means that bones tend to fuse. The AS causes the vertebrae to swell in the spine. Therefore, based on protein interaction network analysis, we conducted in-depth research on the molecular mechanism of key regulatory factors in the AS disease process. We carried out a differential analysis of the expression of miRNAs in disease samples and miRNAs in normal samples. Protein network interaction analysis is performed according to a group of target genes regulated by significant differentially expressed miRNAs and clustered into an interaction module. In addition, enrichment analysis of functions and pathways was performed on these modular genes. Based on the predictive analysis of multidimensional regulators, we identified a range of regulatory factors that have potential regulatory effects on AS, such as endogenous genes and transcription factors. We obtained 20 differentially expressed miRNAs and 7082 target genes and clustered into 11 modules. Enrichment results showed that these modular genes are mainly involved in the functions and pathways of protein polyubiquitination, neutrophil activation involved in immune response, and Wnt signaling pathway. We revealed ten transcription factors (MYC, NFKB1, and TP53). After network connectivity analysis, we obtained 12 internal drive genes (UBE2D1, CCNF, and NEDD4). These core genes are thought to be potential regulators of AS. MYC is also considered to be a core factor that inhibits SART3 phosphorylation and plays a vital role in the immunological pathogenesis of AS. The combination of the above analysis results can provide a new idea for biologists and medical scientists to study the immune pathogenesis of AS and can provide a valuable reference for subsequent treatment options.


Asunto(s)
Espondilitis Anquilosante/genética , Espondilitis Anquilosante/patología , Perfilación de la Expresión Génica/métodos , Redes Reguladoras de Genes/genética , Humanos , MicroARNs/genética , Mapas de Interacción de Proteínas/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas de Unión al ARN/genética , Factores de Transcripción/genética , Vía de Señalización Wnt/genética
14.
J Environ Manage ; 276: 111205, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-32906071

RESUMEN

Increasingly, modern hydrological technologies are dynamically altering river water flow and drastically affecting river hydrogeochemical cycle regimes globally. The present study focused on the reservoir discharges of artificial floodwaters that influence spatiotemporal variations in the physicochemical and stable isotope compositions in the lower Yellow River (LYR) of China. The surface water samples were collected at the nine sites along the LYR during the pre-, inter-and post-flood periods. Then, the collected samples were analysed with the following standard method. The δD and δ18O slopes of the waterline clearly indicated that the prolonged reservoir water and different water flows impacted the hydrological cycle in the LYR regions compared to GMWL (global meteoric water line) and LMWL (local meteoric water line). The thermal stratification processes of the water in the largest reservoir slightly enriched the heavy isotopes, and physicochemical alteration was neglected. Statistical analysis of two-way ANOVA revealed that the p-values (p < 0.01, p < 0.05) were very strong for most of the variables between the periods, and the linear regression exhibited weak values (R2 = 0.253, R2 = 0.150) at the surface water temperature variations and suggested no significant influence of isotope composition. Overall, the Xiaolangdi reservoir water prolonged time rates, and artificial floodwater flow had a very small effect on the isotope composition; in particular, a large high turbidity concentration in the discharged artificial floodwaters was the only considerable ecological risk condition in the LYR. This kind of proper monitoring work is immensely important and prevents reservoirs from causing hydrological cycle impacts in the LYR and the adjacent coastal ecosystems.


Asunto(s)
Inundaciones , Ríos , China , Ecosistema , Monitoreo del Ambiente , Isótopos
15.
J Thorac Dis ; 12(6): 3035-3042, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32642226

RESUMEN

BACKGROUND: Evaluate the effect of enhanced recovery after surgery (ERAS) protocol on postoperative recovery quality of pectus excavatum patients with Nuss procedure. METHODS: A retrospective study was performed on patients undergoing Nuss procedure from the Department of Thoracic Surgery of The Cancer Hospital of China Medical University between September 2016 and September 2019. Patients were divided into 2 groups by perioperative management: the traditional procedure group (T group) and the ERAS strategy group (E group). The outcome measures were postoperative drainage time, postoperative hospital time, and postoperative complications measured by the Clavien-Dindo method. RESULTS: Of the 168 patients from this time period, 148 met the inclusion criteria (75 in Group T and 73 in Group E). All operations involved in this study were completed successfully. There was no statistical difference between the 2 groups with respect to baseline demographics (P>0.05). In Group E, postoperative drainage time (2.53±0.72 vs. 3.45±2.07 days) and postoperative hospitalization time (4.96±1.48 vs. 7.71±7.78 days) were statistically significantly better than those in Group T (P<0.05). There was no difference in overall postoperative complications as measured by Clavien-Dindo score. CONCLUSIONS: The measures of no indwelling urinary catheter (IDUC), laryngeal mask anesthesia, and indwelling tubule drainage can improve postoperative recovery quality of pectus excavatum patients following Nuss procedure.

16.
Sci Total Environ ; 702: 134802, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31733551

RESUMEN

Reforestation and agricultural conservation have long been recognized as important in reducing on-site soil loss and off-site sediment export. Quantitative assessment of their effectiveness is critical, and assists cost-benefit analysis and decision-making in land management and landscape planning. We applied a paired watershed approach to monitor 1-year sediment export in two watersheds with forest-dominated (reference) and mosaic (target) land use in the Naban River Watershed National Natural Reserve (NRWNNR) in Xishuangbanna, south-western China. Analysis of land-use change in the target watersheds showed decreasing total forest cover (FC) (from 57% to 47%), but increasing FC in steep areas (from 54% to 59%) from 2007 to 2012. A distributed hydrological model (Land-Use Change Impact Assessment, LUCIA) was well calibrated and validated through field data from the two watersheds. Scenarios were created representing different FCs (from 31% to 83%) and agricultural management (as-usual and conservation). Simulation results quantified the relation between FC and sediment export as a logarithmic or logit model, indicating at least one turning point of FC, beyond which further forest reduction should significantly increase sediment export. This point was identified in the range between 57% and 61% of the target watershed under as-usual management; it was shifted to 47%-53% by conservation agriculture. Compared with the reference (with 83% FC), conservation agriculture was able to almost fully compensate for increased sediment export by forest reduction to 57% in 2007. However, when forest was reduced further to 47% in 2012, sediment export increased significantly. We concluded that total FC was as important as FC in montane watershed management in steep areas; and crop type conversion, such as rubber to maize in this study, and on-site agriculture management affect more to sediment export than agricultural expansion. We recommend conservation agriculture as an efficient tool for reducing sediment export on a watershed scale.

17.
Colloids Surf B Biointerfaces ; 132: 281-9, 2015 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-26057246

RESUMEN

To improve the antibacterial activity of Cu(2+), a series of Cu(2+) and/or Nd(3+)-modified layered α-zirconium phosphate (ZrP) was prepared and characterized, and the antibacterial activities of the prepared Cu(2+) and/or Nd(3+)-modified ZrP on Gram-negative Escherichia coli were investigated. The results showed that the basal spacing of ZrP was not obviously affected by the incorporation of Cu(2+), but the basal spacing of the modified ZrP changed into an amorphous state with increasing additions of Nd(3+). An antibacterial mechanism showed that Cu(2+) and Nd(3+) could enter into E. coli cells, leading to changes in ion concentrations and leakage of DNA, RNA and protein. The Cu(2+)- and Nd(3+)-modified ZrP, combining the advantages of Cu(2+) and Nd(3+), displayed excellent additive antibacterial activity and lower cytotoxicity, suggesting the great potential application as an antibacterial powder for microbial control.


Asunto(s)
Antibacterianos/farmacología , Cobre/química , Neodimio/química , Circonio/farmacología , Antibacterianos/química , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Difracción de Rayos X , Circonio/química
18.
Water Sci Technol ; 70(5): 851-7, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25225932

RESUMEN

Graphene oxide (GO) was chemically modified with poly(ethylene imine) (PEI) to improve its colloidal stability and was investigated as a potential adsorbent for the removal of methyl orange (MO). The synthesis of PEI-GO was verified with a Fourier transform infrared spectrometer and thermogravimetric analysis. A series of adsorption experiments were carried out to investigate the adsorption capacity of PEI-GO. Adsorption kinetics and thermodynamics studies were performed, and the thermodynamic parameters were calculated. The results showed that PEI could improve the colloidal stability of GO in aqueous solution, and the obtained PEI-GO showed a macroscopically homogeneous dispersion after more than three months. After standing for 90 days, the Brunauer-Emmett-Teller specific surface area of GO decreased from 353 to 214 m2·g(-1), while that of PEI-GO remained almost unchanged (from 432 to 413 m2·g(-1)). The PEI-GO exhibited significantly faster kinetic and higher adsorption capacity for MO than GO. Moreover, PEI-GO had a good adsorption capacity in the acidic range, and the highest adsorption of MO occurred at pH=6.0. The adsorption of MO on PEI-GO was an endothermic, spontaneous and physisorption process.


Asunto(s)
Compuestos Azo/aislamiento & purificación , Grafito/química , Iminas/química , Óxidos/química , Polietilenos/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Coloides , Cinética , Espectroscopía Infrarroja por Transformada de Fourier , Termodinámica
19.
Mater Sci Eng C Mater Biol Appl ; 43: 622-9, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25175257

RESUMEN

In order to control the release of amoxycillin (AM) with lower cytotoxicity and higher activity, ethylene glycol dimethacrylate was used as the cross-linker, and a series of poly(methacrylic acid) (PMAA) nanogels were prepared to load the AM. Then, the morphology, size, in vitro release property, long-term antibacterial performance, cytotoxicity, stability and activity of this novel AM/PMAA nanogel were investigated. The results showed that the AM/PMAA nanogel sustainably released AM with long-term antibacterial activity. Moreover, the AM/PMAA nanogel could improve the stability of AM. More importantly, this AM/PMAA nanogel showed slighter cytotoxicity than AM alone, suggesting that the AM/PMAA nanogel was a more useful dosage form than AM for infectious diseases.


Asunto(s)
Amoxicilina/administración & dosificación , Antibacterianos/administración & dosificación , Geles , Nanoestructuras , Ácidos Polimetacrílicos/química , Amoxicilina/farmacología , Escherichia coli/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Staphylococcus aureus/efectos de los fármacos
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 29(9): 2585-9, 2009 Sep.
Artículo en Chino | MEDLINE | ID: mdl-19950682

RESUMEN

Titanium nitride (TIN) hard protective films were fabricated on AISI52100 bearing steel surface employing plasma immersion ion implantation and deposition (PIIID) technique. The TiN films were characterized using a variety of test methods. Atomic force microscope (AFM) revealed that the titanium nitride film has extremely smooth surface, very high uniformity and efficiency of space filling over large areas. X-ray diffraction (XRD) result indicated that (200) crystal face of titanium nitride phase is the preferred orientation and three kinds of titanium components exist in the surface modified layer. Tailor fitting analysis of X-ray photoelectron spectroscopy (XPS) combined with Ar ion etching proved that Ti2p(1/2) and Ti2p(3/2) have two peaks in the titanium nitride film layer, respectively. It is shown that different chemical state exists in titanium compound. N(1s) bond energy of XPS has also three fitting peaks at 396.51, 397. 22 and 399.01 eV, corresponding to the nitrogen atom in TiNxOy, TiN and N--N, respectively. Combined with the XPS Tailor fitting analysis results of O(1s) bond energy, it was shown that there is a large amount of titanium nitride phase in addition to a small amount of simple substance nitrogen and oxide of titanium in the surface layer. The whole film system is made up of TiN, TiO2, N--N and Ti--O--N compound.

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