Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.325
Filtrar
2.
Genomics ; 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33610796

RESUMO

Effective and complete control of the invasive weed Mikania micrantha is required to avoid increasing damages. We exogenously applied indole 3-acetic acid (IAA), gibberellin (GA), and N-(2-Chloro-4-pyridyl)-N'-phenylurea (CPPU), and their combinations i.e. IAA + CPPU (IC), GA + CPPU (GC), and GA + IAA + CPPU (GIC), at 5, 10, 25, 50, and 75 ppm against distilled water as a control (CK), to examine their effects on the weed. The increasing concentrations of these hormones when applied alone or in combination were fatal to M. micrantha and led towards the death of inflorescences and/or florets. CPPU and GIC were found as the most effective phytohormones. Transcriptome analysis revealed differential regulation of genes in auxin, cytokinin, gibberellin and abscisic acid signaling pathways, suggesting their role in the prohibition of axillary bud differentiation. Collectively, CPPU and GIC at a high concentration (75 ppm) could be used as a control measure to protect forests and other lands from the invasion of M. micrantha.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33611750

RESUMO

Ordered mesoporous MgO was synthesized via template method by using magnesium nitrate as a precursor and amphiphilic triblock copolymer Pluronic F127 as a template. The products were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and the Brunauer-Emmett-Teller (BET) method was used to calculate the specific surface areas. The effects of aging time, relative humidity, and magnesium nitrate content on the morphology and textural properties of the products were studied. When the aging time was 36 h and the relative humidity was 40%, the ordered mesoporous MgO with uniform pore sizes (3.2 nm), high specific surface areas (517.2 m2/g), and high pore volumes (0.42 cm3/g) were obtained. Furthermore, the adsorption properties of ordered mesoporous MgO as adsorbent for removal of Pb(II) and Cd(II) ions were studied. The adsorption kinetics and isotherm data agreed well with pseudo-second-order model and Langmuir model, indicating that the adsorption of heavy metal ions on the ordered mesoporous MgO was mainly chemical and homogeneous adsorption. The maximum adsorption capacities for Pb(II) and Cd(II) ions were up to 3073.5 mg/g and 1485.1 mg/g, respectively.

4.
BMC Musculoskelet Disord ; 22(1): 209, 2021 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-33612121

RESUMO

BACKGROUND: This study aimed to evaluate the effects of different pretreatment methods on the microbial yield from infectious tissues. METHODS: Strains of Staphylococcus aureus (SA), Escherichia coli (EC) and Candida albicans (CA) were used to construct single-surface, full-surface, and internal infection models in sterile pork tissue. Manual milling (MM), mechanical homogenization (MH), sonificated (SF), dithiothreitol (DTT), and direct culture (DC) were used to pretreat these tissues, the microbial yield from different pretreatment methods were recorded and compared. Moreover, periprosthetic tissues collected intraoperatively from periprosthetic joint infection (PJI) patients were used as a verification. RESULTS: The study showed that the microbial yield from MH pretreatment was significantly higher than that of MM (P < 0.01) and SF pretreatment method (P < 0.01). Furthermore, in the internal infection model, the microbial yield from MH group was also significantly higher than that of SF (P < 0.01), DTT (P < 0.01), and DC group (P < 0.01). Moreover, the number of bacterial colonies obtained from periprosthetic tissues pretreated by MH was significantly higher than pretreated by other pretreatment methods (P = 0.004). CONCLUSIONS: The effects of MH and DTT in microbial yield were significantly higher than that of DC, SF and MM, and these methods can be used to process multiple tissue samples at the same time, which might further improve the diagnostic sensitivity of infectious disease.

5.
Water Res ; 193: 116870, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33545438

RESUMO

Research on decentralized wastewaters deserves special focus due to the potential abundance of emerging organic pollutants including pharmaceutical and personal care products (PPCPs), which might pose serious threats to the local water bodies and even to human health. Constructed wetland (CW) is a common decentralized wastewater treatment technology, with a certain ability to eliminate PPCPs. Nonetheless, PPCPs removal in common CWs is frequently challenging, besides, the removal mechanism remains elusive. Based on our previous study, tidal flow constructed wetlands (TFCWs) is effective in nitrogen removal. Here, 3 TFCWs with different modifications (baffle, plants, both baffle and plants) were constructed to treat raw domestic sewage and specifically to evaluate the removal efficiencies and mechanism of PPCPs. 24 PPCPs including 7 antibiotics, 8 steroid hormones and 9 biocides were detected in the level of 1.10 ± 0.29 ng/L-799 ± 10.6 ng/L in the influents. Consequently, we found that modification with both baffle and plants significantly influenced the removal of PPCPs. Moreover, the highest removal rates of biocides (97.1 ± 0.29%), steroid hormones (99.8 ± 0.02%), and antibiotics (90.2 ± 1.60%) were achieved via both baffles and plants in TFCWs. Based on the mass balance analysis, microbial degradation dominated the removal of PPCPs with a percentage higher than 85.7%, followed by substrate adsorption (5.22 × 10-2-14.3%) and plant uptake (1.66 × 10-3-0.44%). Further, 16S rDNA sequencing analysis revealed that the presence of baffle and plants improve the removal efficiency of PPCPs by means of enhancing microbial diversity and changing dominant microorganisms. Moreover, Thaumarchaeota was potentially the key microorganism in the phylum level for PPCPs elimination by TFCWs through LEfSe (linear discriminant analysis (LDA) effect size) analysis. These findings provide new insights into the removal of PPCPs in CWs.

6.
Nanotechnology ; 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33545693

RESUMO

In this work, a graphene (GR)/MoS2/GR selector was proposed based on first principle calculations. First, MoS2 was chosen as the resistive switching layer due to its high carrier mobility and was doped with nine kinds of dopants. Semiconductor characteristics were still maintained with P, Si, and Ti doping, while the others showed semimetallic properties. Then, heterostructures were built between metal GR and MoS·X (X=S, P, Si, Ti), and the conductivities of MoS·Si and MoS·Ti were obviously improved with the GR electrode through analysis of the impurity orbital contribution to the band energy. The plane average electrostatic potential and the charge density difference show that the Schottky barrier height and width of the GR/MoS·Si interface were the smallest and that the intensity of the built-in electric field was better than that of GR/MoS2 and GR/MoS·Ti. Finally, GR/MoS·X(X=S, Si, Ti)/GR selectors were proposed, and the electronic transmission shows that the ON-state current (Ion) and nonlinear (NL) coefficient of the GR/MoS·Si/GR selector were increased by two and three orders of magnitude, respectively, and the threshold voltage (Vth) was reduced by approximately 1 V, which can better suppress the leakage current in a one-selector one-RRAM(1S1R) cross array. This work may be instructive and valuable for the design and optimization of GR/MoS2/GR selectors.

7.
Food Chem ; 349: 129125, 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33535111

RESUMO

This study investigated the effect of germination time on compositional changes and functionality of whole wheat malt flour (WMF) as well as its influence on cookie quality. The results illustrated that malting resulted in decreases of starch, protein, fat and ash, while it increased dietary fiber, carbohydrate and energy. Gel hydration, emulsifying and foaming ability, pasting viscosity decreased significantly, particularly during the first 2 days of germination. Both bound and immobilized water in WMF decreased with increasing germination time while the concentration and antioxidant capacity of extractable and hydrolyzable phenolic compounds (EPP and HPP) increased significantly in WMF and malt-based cookies. Flours changed from an integrated granular to an irregular tousy structure during germination. The incorporation of WMF induced a distorted "honey-like" comb structure to the cookies. Conclusively, controlled germination not only improves the physicochemical, functional properties of WMF but also increases nutrition value and technological performance of malt-based cookies.

8.
Phys Med Biol ; 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33607641

RESUMO

Bolus is commonly used in MV photon radiotherapy to increase superficial dose and improve dose uniformity for treating shallow lesions. However, irregular patient body contours can cause unwanted air gaps between a bolus and patient skin. The resulting dosimetric errors could be exacerbated in MR-Linac treatments, as secondary electrons generated by photons are affected by the magnetic field. This study aimed to quantify the dosimetric effect of unwanted gaps between bolus and skin surface in an MR-Linac. A parallel-plate ionization chamber and EBT3 films were utilized to evaluate the surface dose under bolus with various gantry angles, field sizes, and different air gaps. The results of surface dose measurements were then compared to Monaco 5.40 Treatment Planning System (TPS) calculations. The suitability of using a parallel-plate chamber in MR-Linac measurement was validated by benchmarking the percentage depth dose and output factors with the microDiamond detector and air-filled ionization chamber measurements in water. A non-symmetric response of the parallel-plate chamber to oblique beams in the magnetic field was characterized. Unwanted air gaps significantly reduced the skin dose. For a frontal beam, skin dose was halved when there was a 5 mm gap, a much larger difference than in a conventional linac. Skin dose manifested a non-symmetric pattern in terms of gantry angle and gap size. The TPS overestimated skin dose in general, but shared the same trend with measurement when there was no air gap, or the gap size was larger than 5 mm. However, the calculated and measured results had a large discrepancy when the bolus-skin gap was below 5 mm. When treating superficial lesions, unwanted air gaps under the bolus will compromise the dosimetric goals. Our results highlight the importance of avoiding air gaps between bolus and skin when treating superficial lesions using an MR-Linac system.

9.
Medicine (Baltimore) ; 100(5): e24562, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33592912

RESUMO

ABSTRACT: We previously identified E26 transformation specific sequence 1 (ETS1) rs73013527 single nucleotide polymorphism associated with RA susceptibility and disease activity. In the present study, we aims to further investigate the association between ETS1 rs73013527 and receptor activator of nuclear factor kappa B ligand (RANKL), an index related to bone destruction and was reported to elevate in RA.We determined genotypes of ETS1 rs73013527, serum RANKL concentration, clinical characteristics (disease duration, disease activity score for 28 painful/swollen joints), and laboratory markers (rheumatoid factor, anti-citrullinated protein antibody, anti-keratin antibody, c-reactive protein, erythrocyte sedimentation rate) of 254 RA cases. Univariate and multivariate analysis were employed to explore the association between ETS1 rs73013527 and serum RANKL levels in RA patients.Univariate and multivariate analysis indicated no association of serum RANKL levels with patient age, gender, clinical characteristics, and laboratory markers. Univariate analysis, not multivariate analysis indicated genotype CT/TT of ETS1 rs73013527 was significantly associated with elevated RANKL levels in RA patients.ETS1 rs73013527 is in relation to serum RANKL levels among patients with RA. ETS1 probably might be an indirect factors involved in RANKL regulation in RA.

10.
Artigo em Inglês | MEDLINE | ID: mdl-33586316

RESUMO

Electrocatalytic nitrogen reduction reaction (NRR) plays a vital role for next-generation electrochemical energy conversion technologies. However, the NRR kinetics is still limited by the sluggish hydrogenation process on noble-metal-free electrocatalyst. Herein, we report the rational design and synthesis of a hybrid catalyst with atomic iron sites anchored on a N,O-doped porous carbon (FeSA-NO-C) matrix of an inverse opal structure, leading to a remarkably high NH3 yield rate of 31.9 µgNH3 h-1 mg-1cat. and Faradaic efficiency of 11.8% at -0.4 V for NRR electrocatalysis, outperformed almost all previously reported atomically dispersed metal-nitrogen-carbon catalysts. Theoretical calculations revealed that the observed high NRR catalytic activity for the FeSA-NO-C catalyst stemmed mainly from the optimized charge-transfer between the adjacent O and Fe atoms homogenously distributed on the porous carbon support, which could not only significantly facilitate the transportation of N2 and ions but also effectively decrease the binding energy between the isolated Fe atom and *N2 intermediate and the thermodynamic Gibbs free energy of the rate-determining step (*N2 → *NNH). A proof-of-concept Zn-N2 battery with FeSA-NO-C as the cathode demonstrated the self-power capability to convert N2 into NH3 while delivering a power density of up to 4.5 mW cm-2 and an energy density of 692.9 Wh kg-1.

11.
J Environ Manage ; 285: 112147, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33607560

RESUMO

Land degradation is a global problem caused by improper agricultural practices. In tropical China, the rubber (Hevea brasiliensis) plantations are predominantly practiced on forest-cleared lands, considering their sustainable land management potential compared to annual cropping. However, all rubber plantations may not have similar land management capacity. Soil quality index (SQI) can reveal the overall soil status with a single score, which is an efficient tool to evaluate the soil quality of each category of rubber plantations. We investigated 23 soil physical and chemical parameters of three categories of rubber plantations and a primary rainforest, and derived SQI based on these parameters. Soil samples were collected from a rubber monoculture (RM), a rubber-Camellia sinensis agroforestry (RT), a rubber-Dracaena cochinchinensis agroforestry (RD), and a primary rainforest (RF). The results showed that the SQI value of the RM decreased by 15.50% compared to the RF, with a significant degree of soil nutrient loss (18.90%). This indicates that monocultural rubber cultivation is causing land degradation to some extent. However, the SQI was significantly enhanced by rubber-based agroforestry practices (25.30% by RT and 33.10% by RD) compared to the RM, suggesting that polyculture practices are suitable to recover the soil quality in degraded agricultural lands. Moreover, the chemical parameters contributed more to the SQI than did the physical parameters, indicating that nutrient management is important in soil quality recovery. Overall, our results suggest that agroforestry should be preferred over monoculture in the rubber plantations for sustainable land management in tropical China.

13.
Artigo em Inglês | MEDLINE | ID: mdl-33523382

RESUMO

The vegetation in the farming-pastoral ecotone in northern China is influenced by both natural and anthropogenic factors and has undergone drastic changes in the past decades. The farming-pastoral ecotone is the transition zone from agriculture to animal husbandry. The ecological environment of this ecotone is complex and fragile. Most researches have primarily focused on the entire farming-pastoral ecotone, seldomly considering the differences between different ecological zones characterized by soil, climate, and biome conditions. Based on the long time series of leaf area index (LAI) data, meteorological data, and land-use dataset, this study analyzed LAI variation trends, the correlations between LAI and climate factors, and the impact of land-use type change on vegetation in the farming-pastoral ecotone in northern China. Moreover, this paper makes a full study of the changes of the whole study area from the perspective of the differences between different ecological zones. The results showed that over 36 years, areas with vegetation improvements were considerably larger than those with degradations. However, there were still 49.56% of the total area showing no significant vegetation change. There are differences in vegetation change and response to climate between the forest ecological zones and the grassland ecological zones. The vegetation improvement trends of the forest ecological zones were larger and more sensitive to temperature, while the vegetation improvements of the grassland ecological zones were relatively small, and were more sensitive to precipitation. Human activities promote LAI changes in areas close to the forest ecological zones. The change of land use indicates that the decrease of the overall natural vegetation area has not resulted in decreasing LAI. And there is a growing trend of woodland area in the grassland ecological zones. The study provides a theoretical basis for the management of the environment and vegetation in the farming-pastoral ecotone in northern China.

14.
Artigo em Inglês | MEDLINE | ID: mdl-33540632

RESUMO

The scientific analysis of spatial-temporal differentiation characteristics and driving factors of illegal land use is of great significance for the formulation and optimization of policies to control the emergence of illegal land use. This paper establishes two variable systems of illegal land use and its driving factors, defined the multidimensional characteristic variables of illegal land use and analyzes the relationships among them by the Pearson's correlation coefficient; In addition, the spatial-temporal characteristics of each variable of illegal land use from 2004 to 2017 are described by the spatial autocorrelation analysis; Finally, based on the geographical detectors, the influence direction and degree of the factors of economic structure, social structure and land market behavior on the characteristics of different illegal land use are studied. The results show that the spatial agglomeration of different characteristics of illegal land use had been weakening from 2004 to 2017, but the rate of weakening was different, and L-L agglomeration changed between Xinjiang and other central-western provinces, H-H agglomeration changed in the coastal regions of the central-eastern of China, the level and ability of the central government and local governments to govern illegal land use is constantly improving on the whole; the compositional factors of economic development structure, social development structure, and land market behavior of driving factors had different influence in the degree, the location or the direction of different characteristics of illegal land use. According to the spatial-temporal characteristics and the differences of driving factors, managers can formulate differentiated illegal land use control policies, which will help to control the occurrence of illegal land use and help the settlement of illegal land use cases, and ultimately achieve sustainable development.

15.
J Atheroscler Thromb ; 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33536383

RESUMO

AIM: ATP-binding cassette (ABC) transporters and endonuclease-exonuclease-phosphatase family domain containing 1 (EEPD1) are reported to regulate cellular cholesterol efflux in macrophages. Bioinformatics analysis has revealed that ABCG1 and EEPD1 might be potential targets of microRNA (miR)-320b. This study aimed to elucidate the roles of miR-320b in cholesterol efflux from macrophages and the pathogenesis of atherosclerosis. METHODS: Microarray was conducted to profile microRNA (miRNA) expression, and quantitative real-time PCR (qPCR) was used to validate the differentially expressed miRNAs in peripheral blood mononuclear cells of coronary artery disease (CAD) patients and healthy controls. Luciferase assay was conducted to evaluate the activity of reporter construct containing the 3´-untranslated region (3´-UTR) of target genes. Besides, NBD-cholesterol efflux induced by high-density lipoprotein (HDL) and lipid-free apolipoprotein A1 (apoA1) was detected using fluorescence intensity, respectively. Apoe-/- mice were injected with adeno-associated virus (AAV)2-miR-320b or control via tail vein, thereafter fed with 14 week atherogenic diet to study the roles of miR-320b in vivo. RESULTS: MiR-320b was highly expressed in CAD patients compared with that in the healthy controls in both the microarray analysis and qPCR analysis. In vitro study showed that miR-320b decreased HDL- and apoA1- mediated cholesterol efflux from macrophages partly by directly targeting ABCG1 and EEPD1 genes and partly via suppressing the LXRα-ABCA1/G1 pathway. Consistently, in vivo administration of AAV2-miR-320b into Apoe-/- mice attenuated cholesterol efflux from peritoneal macrophages, which showed reduced expression of ABCA1/G1 and EEPD1, and increased lipid LDL-C level, with a down-regulation of hepatic LDLR and ABCA1. AAV2-miR-320b treatment also increased atherosclerotic plaque size and lesional macrophage content and enhanced pro-inflammatory cytokines levels through the elevated phosphorylation level of nuclear factor-κB p65 in macrophages. CONCLUSION: We identify miR-320b as a novel modulator of macrophage cholesterol efflux and that it might be a promising therapeutic target for atherosclerosis treatment.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33599063

RESUMO

Electrocatalysts play a key role in accelerating the sluggish electrochemical CO2 reduction (ECR) involving multi-electron and proton transfer. Herein, we develop a proton capture strategy via accelerating the water dissociation reaction catalyzed by transition metal nanoparticles (NPs) adjacent to atomically dispersed and nitrogen coordinated single nickel (Ni-Nx) active sites to accelerate the proton transfer to the latter for boosting the intermediate protonation step, and hence the whole ECR process. This accelerated protonation process is amply demonstrated experimentally. Aberration-corrected scanning transmission electron microscopy and X-ray absorption spectroscopy, together with theoretical calculations, reveals that Ni NPs accelerate the adsorbed H (Had) generation and transfer to the adjacent Ni-Nx sites for boosting the intermediate protonation and the overall ECR processes. This proton capture strategy is universal to design and prepare for various high-performance catalysts for diverse electrochemical reactions even beyond ECR.

18.
Microb Pathog ; 152: 104769, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33524569

RESUMO

OBJECTIVES: Syphilis is a sexually transmitted disease of global prevalence. Current diagnostic methods lack sensitivity and specificity, which limits the early diagnosis and prognosis of the disease. MiRNAs hold great promise as potential biomarkers for infectious diseases diagnosis. We previously profiled the expression of miRNAs in PBMCs from patients with different stages of syphilis. We aimed to further confirm the miR-101-3p, miR-195-5p, and miR-223-3p expression profiles and evaluate their diagnostic value in syphilis infection. METHODS: The expression levels of PBMC-derived miR-101-3p, miR-195-5p, and miR-223-3p were analyzed in 133 syphilis patients, 18 non-syphilis patients, and 23 healthy controls by RT-qPCR. ROC analysis was used to evaluate the differentiation power of these miRNAs in syphilis diagnosis, while the correlation between the expression of these miRNAs and TRUST titer was also statistically analyzed. RESULTS: These miRNAs were significantly upregulated in syphilis patients in a stage-specific manner. ROC analysis indicated that miR-223-3p was powerful in discriminating between controls and patients with early, primary, secondary, and latent syphilis, as well as serological cure; the miR-195-5p/miR-223-3p panel showed an improved capacity to differentiate between syphilis patients, primary, or serofast-stage syphilis and controls, while the three miRNAs combined showed an improved capacity to differentiate latent syphilis or serological cure from controls. Importantly, miR-101-3p and miR-223-3p singly or jointly could specifically distinguish syphilis from non-syphilis patients. Moreover, TRUST titer was significantly correlated with miR-101-3p expression. CONCLUSIONS: MiR-101-3p, miR-195-5p, and miR-223-3p might singly or jointly be potential diagnostic biomarkers at different stages of syphilis.

19.
Cancer Res ; 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589518

RESUMO

Mutant KRAS tumors are associated with poor outcomes at least in part due to decreased therapeutic sensitivity. Here we show that KRAS mutations are associated with resistance to monotherapy and combination therapy with Poly-(ADP-ribose) polymerase inhibitors (PARPi) and immune checkpoint blockade with anti-PD-L1 antibodies. In mutant KRAS tumors, inhibition of KRAS signaling with MEK inhibitors (MEKi) triggered and amplified PARPi-induced DNA damage, cytosolic double-stranded DNA accumulation, STING pathway activation and CD8+ T cell recruitment. Moreover, MEKi decreased myeloid-derived suppressor cell infiltration in part by inhibiting IL-6 and GM-CSF production. Importantly, addition of MEKi to PARPi and anti-PD-L1 resulted in marked tumor inhibition in immunocompetent mutant KRAS tumor models. These studies provide the underlying mechanistic data to support evaluation of PARPi, MEKi, and anti-PD-L1 combination in clinical trials of mutant KRAS tumors.

20.
Talanta ; 225: 122090, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33592799

RESUMO

Tumor-derived exosomes that inherit molecular information on parental cells hold great promise for cancer diagnostics. Currently, two main technical challenges, time-consuming and labor-intensive isolation of exosome and nucleic acid extraction with limited recovery that have restricted the detection of ultralow abundance exosomal nucleic acids. Here, we proposed a simple, efficient and "lab in a tube" system for the detection of exosomal nucleic acids, which fully integrated exosomes enrichment using immunomagnetic beads (IMB) (10 min), fast exosomes lysis based on NP-40 lysate (5 min) and sensitive loop-mediated isothermal amplification (LAMP) in a tube. This method was demonstrated by detecting two exosomal long noncoding RNA biomarkers of gastric cancer (HOTTIP and lncRNA-GC1) with a dynamic detection ranging from 300 ng/µL to 10 ng/µL, and the detection limit of LAMP was 10 ng/µL. Additionally, this platform exhibited good performance in the analysis of exosomal HOTTIP RNA directly in human serum samples, which has the potential for detection of low-abundance exosomal nucleic acid biomarkers from cancers.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA