Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Org Biomol Chem ; 21(47): 9356-9361, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-37927135

RESUMEN

The cleavage of C-C bonds in oxidized lignin model compounds is a highly effective methodology for achieving lignin depolymerization, as well the generation of N-substituted aromatics. Here, density functional theory calculations were performed to understand the mechanism of the transformation of an oxidized lignin model compound (ligninox) and hydroxylamine hydrochloride to N-substituted aromatics. The reaction was proposed to proceed via an energetically viable mechanism featuring the initial production of HOAc acting as proton bridge. According to our calculations, Z-type oxime is the major intermediate of the reaction, with an energy barrier of 22.9 kcal mol-1, owing to the weak interactions between methoxy and oximino groups being stronger than that of E-type oxime. Additionally, the hydroxy addition is the rate-determining step, with an energy barrier of 27.0 kcal mol-1. Moreover, the huge net energy change of Beckmann and abnormal Beckmann rearrangements is the main overall thermodynamic driving force for producing N-substituted aromatics from oximes. The theoretical results have provided a clear picture of how ligninox transforms into N-substituted aromatics and are expected to provide valuable theoretical guidance for lignin depolymerization.

2.
Inorg Chem ; 62(43): 17946-17953, 2023 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-37851378

RESUMEN

The detailed mechanisms of Ni-catalyzed ligand-controlled cyclization/cross-coupling of o-bromobenzenesulfonyl acrylamide (1a) with trifluoromethyl alkene were investigated by DFT calculations. The computational results support a single-electron reduction of NiII precatalyst to give BrNiIL species, which would react with 1a via oxidative addition to afford the (Ar)NiIIILBr2 complex. The subsequent cyclizations did not proceed until (Ar)NiIIILBr2 was reduced to the key (Ar)NiIL complex. For the bpy-involving reaction, the subsequent steps include nucleophilic attack to the carbonyl carbon atom, N-C bond breaking, intramolecular migratory insertion, as well as concerted C-C cross-coupling and ß-F elimination. While the ligand of terpyridine promotes the 7-endocyclization followed by stepwise migratory insertion and ß-F elimination to afford 2-benzazepine 2,5-dione. For both reactions, a theoretical study implied that the most favorable mechanism involved a NiI-NiIII-NiI catalytic cycle. The origins of the chemoselectivity, coupled with the factors responsible, were addressed.

3.
Front Plant Sci ; 14: 1139094, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36950353

RESUMEN

In a complex agricultural region, determine the appropriate crop for each plot of land to maximize the expected total profit is the key problem in cultivation management. However, many factors such as cost, yield, and selling price are typically uncertain, which causes an exact programming method impractical. In this paper, we present a problem of crop cultivation planning, where the uncertain factors are estimated as fuzzy parameters. We adapt an efficient evolutionary algorithm, water wave optimization (WWO), to solve this problem, where each solution is evaluated based on three metrics including the expected, optimistic and pessimistic values, the combination of which enables the algorithm to search credible solutions under uncertain conditions. Test results on a set of agricultural regions in East China showed that the solutions of our fuzzy optimization approach obtained significantly higher profits than those of non-fuzzy optimization methods based on only the expected values.

4.
Inorg Chem ; 62(9): 3904-3915, 2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36799526

RESUMEN

Density functional theory (DFT) calculations were performed to study the palladium/Brønsted acid-catalyzed methoxycarbonylation and hydromethoxylation reactions of internal alkene. The calculated results show that the pyridyl group (N atom) in bidentate phosphine ligand with built-in base (L1) plays a crucial role in controlling the selectivity. With the help of the pyridyl group, the methanolysis steps in the methoxycarbonylation reaction and the hydromethoxylation reaction become easy, and both the linear ester methyl 3,4-dimethylpentanoate (P1) and the hydromethoxylation product 2-methoxy-2,3-dimethylbutane (P2) could be obtained. In contrast, the possibility of leading to branched ester P1' was ruled out according to our calculations. The steric effect could account for the observed selectivity. In the presence of the DPEphos ligand (L2) that does not bear the pyridyl group, the methanolysis step in the methoxycarbonylation reaction becomes the rate-determining step with a high overall energy barrier. Neither linear nor branched methoxycarbonylation product could be generated. The palladium/Brønsted acid co-catalyzed hydromethoxylation also become difficult without the assistance of the pyridyl group in the presence of the L2 ligand. Instead, TsOH-catalyzed hydromethoxylation reaction could take place to generate the ether product P2.

5.
J Org Chem ; 88(4): 2296-2305, 2023 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-36727513

RESUMEN

A simple and efficient electrochemical sulfonylation of organoboronic acids with sodium arylsulfinate salts has been reported for the first time. A variety of aryl, heteroaryl, and alkenylsulfones were obtained in good to excellent yields via a simple electrochemical sulfonylation of various arylboronic acids, heterocyclic boronic acids, or alkenylboronic acids with sodium arylsulfinate at room temperature in 5 h under the catalyst-free and additive-free conditions. A plausible mechanism has been proposed based on various radical-trapping and CV control experiments.

6.
Chem Asian J ; 18(8): e202201266, 2023 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-36852827

RESUMEN

The development of the merger of a Ni(II) catalyst with an appropriate photocatalyst under visible-light irradiation provides a new strategy for realizing direct functionalization of C(sp3 )-H bonds. Mechanistically, whether the reduction of Ni catalyst to form a Ni(0) species is necessary in the dual catalysis still remains under debate. Herein, DFT calculations were carried out to gain a mechanistic insight into the enantioselective acylation of α-amino C(sp3 )-H bonds to furnish α-amino ketones via photoredox and Ni dual catalysis. A feasible mechanistic pathway for the Ni catalysis via the Ni(I)-Ni(III)-Ni(II)-Ni(III)-Ni(I) cycle is suggested with the sequential elementary steps of oxidative addition, single electron reduction, radical addition, and reductive elimination in leading to the final product, whereas a nickel catalytic cycle, Ni(I)-Ni(0)-Ni(II)-Ni(III)-Ni(I), might not be feasible for the photoredox and Ni dual-catalyzed acylation of α-amino C(sp3 )-H bonds. The origin of the stereoselectivity for this reaction is also discussed, which could be attributed to the minimization of the steric hindrance between the alkyl moiety of radical part and phenyl group of the chiral ligand.

7.
Int Urol Nephrol ; 55(8): 2035-2045, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36809640

RESUMEN

AIM: Chronic kidney disease (CKD) is increasingly recognized as a global health issue. There is a paucity of published data on the prevalence and risk factors of CKD in less-developed regions. This study aims to evaluate and update the prevalence and risk factors of CKD in a city of Northwestern China. METHODS: Based on a prospective cohort study, a cross-sectional baseline survey was conducted between 2011 and 2013. The data on the epidemiology interview, physical examination, and clinical laboratory test were all collected. In this study, 41,222 participants were selected from 48,001 workers in the baseline after excluding objects with incomplete information. The crude and standardized prevalence of CKD were calculated. An unconditional logistic regression model was used to analyze the risk factors associated with CKD among male and female. RESULTS: One thousand seven hundred eighty-eight people were diagnosed with CKD, including 1180 males and 608 females. The crude prevalence of CKD was 4.34% (4.78% males and 3.68% females). The standardized prevalence was 4.06% (4.51% males and 3.60% females). The prevalence of CKD increased with age and was higher in males than in females. In multivariable logistic regression, CKD was significantly associated with the increasing age, drinking, never or occasionally exercise, overweight or obesity, being unmarried, diabetes, hyperuricemia, dyslipidemia and hypertension. CONCLUSION: In this study, the prevalence of CKD was lower than that of the national cross-sectional study. Lifestyle, hypertension, diabetes, hyperuricemia and dyslipidemia were the main risk factors of CKD. The prevalence and risk factors differ between male and female.


Asunto(s)
Diabetes Mellitus , Dislipidemias , Hipertensión , Hiperuricemia , Insuficiencia Renal Crónica , Humanos , Masculino , Femenino , Estudios Transversales , Hiperuricemia/complicaciones , Prevalencia , Estudios Prospectivos , Insuficiencia Renal Crónica/complicaciones , Factores de Riesgo , Hipertensión/epidemiología , Diabetes Mellitus/epidemiología , Dislipidemias/complicaciones , China/epidemiología , Tasa de Filtración Glomerular
8.
Ecotoxicol Environ Saf ; 249: 114438, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-38321659

RESUMEN

Currently few studies have explored the relationship between exposure to gaseous pollutants and metabolic health indicators in patients, especially in patients with metabolic syndrome (Mets). This study collected 15,520 patients with Mets in a prospective cohort of nearly 50,000 people with 7 years of follow-up from 2011 to 2017, and matched air pollutants and meteorological data during the same period. The mixed effects model was used to analyze the relationship between different short exposure windows (1-week, 1-month, 2-month, and 3-month) of gaseous pollutants (SO2, NO2, and O3) and the metabolic health indicators of patients after controlled the confounding factors. Stratified analysis was performed by demographic characteristics and behavioral factors. The effects of gaseous pollutants on patients with different Met components were also analyzed. The results showed that the short-term exposure to SO2, NO2, and O3 had a certain effect on the metabolic health indicators of patients with Mets in different exposure windows, and with the extension of the exposure window period, the effects increased. The stratified analysis showed that gender, age, and life behaviors might modify these detrimental effects. In addition, the effects of gaseous pollutants on metabolic health indicators in G4 and G7 were more obvious than other Met components, and the effects of gaseous pollutants on the level of LDL-C were found to be statistically significant in most components. Therefore, patients with Mets should pay more attention to the influence of gaseous pollutants to take appropriate protection to reduce potential health risk.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Ambientales , Síndrome Metabólico , Humanos , Contaminación del Aire/análisis , Contaminantes Ambientales/análisis , Gases/análisis , Material Particulado/análisis , Estudios Prospectivos , Contaminantes Atmosféricos/análisis , China , Dióxido de Nitrógeno/análisis
9.
Dalton Trans ; 51(31): 11868-11875, 2022 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-35876237

RESUMEN

A green and sustainable electrochemical hydroboration of carbonyl compounds with HBpin has been reported for the first time. Under catalyst-free and additive-free mild reaction conditions the corresponding boronic esters were obtained in excellent yields via the simple electrochemical hydroboration of various aldehydes and ketones with HBpin at room temperature. The scale-up reaction demonstrated potential practical applications. A plausible reaction mechanism was proposed based on the corresponding deuterium-labelling, radical inhibition and cyclic voltammetry experiments.


Asunto(s)
Aldehídos , Cetonas , Aldehídos/química , Boro , Catálisis , Ésteres/química , Cetonas/química
10.
Plant Cell ; 34(9): 3383-3399, 2022 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-35708659

RESUMEN

Photosynthesis and the biosynthesis of many important metabolites occur in chloroplasts. In these semi-autonomous organelles, the chloroplast genome encodes approximately 100 proteins. The remaining chloroplast proteins, close to 3,000, are encoded by nuclear genes whose products are translated in the cytosol and imported into chloroplasts. However, there is still no consensus on the composition of the protein import machinery including its motor proteins and on how newly imported chloroplast proteins are refolded. In this study, we have examined the function of orf2971, the largest chloroplast gene of Chlamydomonas reinhardtii. The depletion of Orf2971 causes the accumulation of protein precursors, partial proteolysis and aggregation of proteins, increased expression of chaperones and proteases, and autophagy. Orf2971 interacts with the TIC (translocon at the inner chloroplast envelope) complex, catalyzes ATP (adenosine triphosphate) hydrolysis, and associates with chaperones and chaperonins. We propose that Orf2971 is intimately connected to the protein import machinery and plays an important role in chloroplast protein quality control.


Asunto(s)
Cloroplastos , Proteínas de Plantas , Núcleo Celular , Proteínas de Cloroplastos , Chaperonas Moleculares , Transporte de Proteínas
11.
Front Endocrinol (Lausanne) ; 13: 864008, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35498438

RESUMEN

Background: Cardiovascular autonomic neuropathy (CAN) is common in patients with type 2 diabetes mellitus (T2DM), mainly presented as decreased heart rate variability (HRV) which often leads to cardiac death. However, HRV measurement is not convenient in most clinics. Therefore, identifying high-risk patients for CAN in diabetes with easier measurements is crucial for the early intervention and prevention of catastrophic consequences. Methods: In this cross-sectional study, 675 T2DM patients with normocalcemia were selected. Of these, they were divided into two groups: normal HRV group (n = 425, 100 ms≤ SDNN ≤180 ms) vs. declined HRV group (n = 250, SDNN <100 ms). All patients' clinical data were collected and the correlation of clinical variables with HRV were analyzed by correlation and logistic regression analysis. The area below the ROC curve was used to evaluate the predictive performance of serum calcium on HRV. Results: In this study, declines in HRV were present in 37.0% of T2DM patients. Significant differences in albumin-adjusted serum calcium levels (CaA) (8.86 ± 0.27 vs. 9.13 ± 0.39 mg/dl, p <0.001) and E/A (0.78 ± 0.22 vs. 0.83 ± 0.26, p = 0.029) were observed between declined HRV and normal HRV groups. Bivariate linear correlation analysis showed that CaA and E/A were positively correlated with HRV parameters including SDNN (p < 0.001), SDNN index (p < 0.001), and Triangle index (p < 0.05). The AUC in the ROC curve for the prediction of CaA on HRV was 0.730 (95% CI (0.750-0.815), p < 0.001). The cutoff value of CaA was 8.87 mg/dl (sensitivity 0.644, specificity 0.814). The T2DM patients with CaA <8.87 mg/dl had significantly lower HRV parameters (SDNN, SDNN index, rMSSD, and triangle index) than those with CaA ≥8.87 mg/dl (p < 0.01, respectively). Multivariate logistic regression analysis showed a significantly increased risk of declined HRV in subjects with CaA level <8.87 mg/dl [OR (95% CI), 0.049 (0.024-0.099), p < 0.001]. Conclusions: Declined HRV is associated with a lower CaA level and worse cardiac function. The serum calcium level can be used for risk evaluation of declined HRV in T2DM patients even within the normocalcemic range.


Asunto(s)
Diabetes Mellitus Tipo 2 , Calcio , Estudios Transversales , Diabetes Mellitus Tipo 2/complicaciones , Frecuencia Cardíaca , Humanos , Curva ROC
12.
Anal Cell Pathol (Amst) ; 2022: 4220786, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35103233

RESUMEN

Basal cell carcinoma (BCC) is the most common malignancy worldwide, with increasing incidence. BCCs present low mortality but high morbidity, and its pathogenesis remains unclear. Eph receptors have been implicated in tumorigenesis. EphA7 plays a role as a tumor suppressor in certain cancers. We checked EphA7 expression levels and methylation status in a set of BCCs, benign skin diseases, and compound nevus tissue samples using immunohistochemistry. EphA7 protein was positively expressed in normal basal cells, benign skin diseases, and compound nevus cells, but lost in areas of BCC tissues. We detected hypermethylation in BCC tissue samples with reduced expression of EphA7. There is a significant relationship between the expression level of EphA7 receptor protein and the methylation status of CpG islands in the EphA7 promoter region (P < 0.001). To our knowledge, this is the first study to report the EphA7 expression profile and hypermethylation of EphA7 in BCC. The role of the EphA7 gene and the status of hypermethylation in tumorigenesis and treatment of BCC warrant further investigation.


Asunto(s)
Carcinoma Basocelular , Islas de CpG , Metilación de ADN , Receptor EphA7 , Neoplasias Cutáneas , Carcinoma Basocelular/genética , Carcinoma Basocelular/metabolismo , Humanos , Regiones Promotoras Genéticas , Receptor EphA7/biosíntesis , Receptor EphA7/genética , Receptor EphA7/metabolismo , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo
13.
Cerebrovasc Dis ; 51(2): 225-234, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34644707

RESUMEN

INTRODUCTION: It is not clear whether serum uric acid (SUA) levels and their changes over time are associated with the risk of stroke. A 7-year prospective cohort study in northwest China was conducted to analyze effects of SUA and their changes on the risk of stroke. METHODS: A total of 23,262 individuals without cardiovascular disease in the Jinchang cohort were followed up for an average of 5.26 years. The Cox proportional hazard model was used to estimate the hazard ratios (HRs) and 95% confidence interval (95% CI) of stroke incidence to SUA and relative changes in SUA. Sensitivity analysis was performed after controlling the effect of renal insufficiency. RESULTS: Baseline SUA and relative changes in SUA were positively correlated with the incidence of stroke in both males and females (p for overall association <0.0001). Stroke risk increased by 4.6% per 10% increase in the relative change of SUA (HR = 1.046, 95% CI, 1.007-1.086). The fully adjusted regression analysis demonstrated that only the large gain (>30%) in SUA was associated with an increased risk of stroke by 36.5% (95% CI, 1.8-83.0%), compared with the reference group (participants within ±10% changes in SUA). The same trend was observed in people with normal baseline SUA. In the unadjusted model, the risk of stroke associated with elevated SUA was significantly higher in the hyperuricemia group than in the normal SUA group. CONCLUSION: High initial SUA concentration and an increase in SUA concentration over time would increase the risk of stroke, and this means that there is no safe increase in SUA.


Asunto(s)
Hiperuricemia , Accidente Cerebrovascular , China/epidemiología , Estudios de Cohortes , Femenino , Humanos , Hiperuricemia/diagnóstico , Hiperuricemia/epidemiología , Masculino , Estudios Prospectivos , Factores de Riesgo , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/epidemiología , Ácido Úrico
14.
Mediators Inflamm ; 2020: 3560793, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32565723

RESUMEN

In patients with chronic kidney disease, the abnormal activation of inflammatory pathways is usually an important factor leading to renal fibrosis and further deterioration of renal function. Finding effective intervention targets of the inflammatory signaling pathway is an important way to treat chronic kidney disease. As a newly discovered lysosomal membrane protein, the correlation between SID1 transmembrane family member 2 (Sidt2) and the inflammatory signaling pathway has not been reported. The aim of this study was to investigate the effect of Sidt2 on inflammation by inhibiting the expression of the Sidt2 gene in a mouse mesangial cell line mediated by a lentiviral CRISPR/Cas9 vector. Hematoxylin and eosin staining and microscopy found that the mesangial cells lost their normal morphology after inhibiting the expression of Sidt2, showing that the cell body became smaller, the edge between the cells was unclear, and part of the nucleus was pyknotic and fragmented, appearing blue-black. The expressions of IKK ß, p-IKK α/ß, NF-κB p65, p-NF-κB p65, p-IκBα, IκBα, and TNF-α in the NF-κB pathway of the Sidt2 -/- group were higher than those of the Sidt2 +/+ group. p-Jak2 and IL6 increased in the Jak/Stat pathway, and p-ERK and p-P38 increased in the MAPK pathway. The expressions of IKK ß, p-IKK α/ß, NF-κB p65, p-NF-κB p65, p-IκBα, IκBα, and TNF-α in the NF-κB pathway of the Sidt2 +/++LPS group were significantly higher than those in the Sidt2 +/+ group. The expressions of IKK ß, p-IKK α/ß, NF-κB p65, p-NF-κB p65, p-IκBα, IκBα, and TNF-α in the Sidt2 -/-+LPS group were higher than those in the Sidt2 -/- group. The expressions of p-IKK α/ß, NF-κB p65, p-NF-κB p65, p-IκBα, IκBα, and TNF-α in the Sidt2 -/-+LPS group were higher than those in the Sidt2 +/++LPS group. In the Jak/Stat pathway, the protein expressions of p-Jak2 and IL6 in the Sidt2 +/++LPS group were higher than those in the Sidt2 +/+ group. The expressions of p-Jak2 and IL6 in the Sidt2 -/-+LPS group were higher than those in the Sidt2 -/- group. The expressions of p-Jak2 and IL6 in the Sidt2 -/-+LPS group were higher than those in the Sidt2 +/++LPS group. The expressions of p-JNK, p-ERK, p-P38, and ERK in the MAPK pathway in the Sidt2 +/++LPS group were higher than those in the Sidt2 +/+ group. The expressions of p-JNK, p-ERK, p-P38, and ERK in the Sidt2 -/-+LPS group were higher than those in the Sidt2 -/- group. The expressions of p-JNK, p-ERK, p-P38, and ERK in the Sidt2 -/-+LPS group were higher than those in the Sidt2 +/++LPS group. These data suggested that deletion of the Sidt2 gene changed the three inflammatory signal pathways, eventually leading to the damage of glomerular mesangial cells in mice.


Asunto(s)
Perfilación de la Expresión Génica , Inflamación/metabolismo , Células Mesangiales/metabolismo , Proteínas de Transporte de Nucleótidos/metabolismo , Animales , Sistemas CRISPR-Cas , Citocinas/metabolismo , Regulación de la Expresión Génica , Tasa de Filtración Glomerular , Quinasa I-kappa B/metabolismo , Lentivirus/genética , Lipopolisacáridos/metabolismo , Lisosomas/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones , Ratones Noqueados , Inhibidor NF-kappaB alfa/metabolismo , Transducción de Señal , Factor de Transcripción ReIA/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo
15.
Environ Sci Pollut Res Int ; 27(21): 26249-26261, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32361969

RESUMEN

Arsenic (As) is a ubiquitous carcinogen and environmental toxin. In China, rice consumption is a major dietary source of inorganic As. Thus, the development of strategies to decrease As accumulation in rice is of considerable importance. In this study, we investigated variation in As accumulation and translocation among 74 hydroponically grown rice cultivars in Jiangsu Province, China. We also examined the relationships between As accumulation and translocation, and the uptake of elements such as silicon (Si), phosphorus (P), iron (Fe), and manganese (Mn). Our results showed 3.43-, 2.7-, and 6.34-fold variations in shoot As concentration, root As concentration, and root-to-shoot As translocation factors (TFs), respectively, among 74 cultivars, indicating that cultivar genotype significantly affected As accumulation and translocation. Redundancy analysis revealed that As uptake and transport were more closely related to P and Mn uptake than to Si and Fe uptake, for all 74 rice genotypes. In addition, the 20 cultivars that accumulated the least shoot As (low-As), and those that accumulated the most shoot As (high-As), exhibited different strategies in response to As exposure. The As TFs were key factors influencing shoot As concentrations in high-As cultivars, but this was not the case in low-As cultivars. In the latter, more accumulated As were sequestered in roots, which restricted As translocation to shoots, thus leading to lower shoot As concentrations. In addition, the shoot As concentrations of various rice cultivars and their parents differed. The low-As rice cultivar YJ2 exhibited a significantly lower shoot As concentration than its parents, suggesting that it is possible to breed low-As rice cultivars from parents that also exhibit low-As characteristics.


Asunto(s)
Arsénico/análisis , Oryza , Contaminantes del Suelo/análisis , China , Raíces de Plantas/química
16.
Artículo en Inglés | MEDLINE | ID: mdl-31500133

RESUMEN

Nickel (Ni) is a ubiquitous environmental toxicant and carcinogen, and rice is a major dietary source of Ni for the Chinese population. Recently, strategies to decrease Ni accumulation in rice have received considerable attention. This study investigated the variation in Ni accumulation and translocation, and also multi-element (silicon (Si), phosphorus (P), iron (Fe), and manganese (Mn)) uptake and transport among 72 rice cultivars from Jiangsu Province, China, that were grown under hydroponic conditions. Our results showed a 2.2-, 4.2-, and 5.3-fold variation in shoot Ni concentrations, root Ni concentrations, and translocation factors (TFs) among cultivars, respectively. This suggests that Ni accumulation and translocation are significantly influenced by the genotypes of the different rice cultivars. Redundancy analysis of the 72 cultivars revealed that the uptake and transport of Ni were more similar to those of Si and Fe than to those of P and Mn. The Ni TFs of high-Ni cultivars were significantly greater than those of low-Ni cultivars (p < 0.001). However, there were no significant differences in root Ni concentrations of low-Ni and high-Ni cultivars, suggesting that high-Ni cultivars could translocate Ni to shoots more effectively than low-Ni cultivars. In addition, the cultivars HD8 and YD8 exhibited significantly lower levels of Ni accumulation than their parents (p < 0.05). Our results suggest that breeding can be an effective strategy for mitigating excessive Ni accumulation in rice grown in Ni-contaminated environments.


Asunto(s)
Agricultura , Genotipo , Hierro/análisis , Níquel/análisis , Oryza , Fósforo/análisis , Silicio/análisis , Contaminantes del Suelo/análisis , China , Manganeso/análisis , Raíces de Plantas/química
17.
Oncol Lett ; 16(3): 3157-3161, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30127909

RESUMEN

The purpose of this study was to investigate the efficacy of radiofrequency ablation (RFA) combined with esophageal stent in treating malignant esophageal stenosis. Seventy patients with malignant esophageal obstruction treated in Department of Gastroenterology from April 2013 to April 2015 in China-Japan Union Hospital of Jilin University were enrolled. They were randomly assigned into the treatment group (radiofrequency ablation combined with esophageal stent) and control group (esophageal stent). To observe the degree of dysphagia, esophageal stenosis diameter, readmission time, adverse events and complications. There was no significant differences in dysphagia and esophageal diameter between the treatment group and the control group within 1-3 months after operation (P>0.05), and the degree of dysphagia and esophageal diameter in the treatment group at postoperative 6 months were better than those in the control group (P=0.018 and 0.038, respectively). The readmission time of the treatment group was also better than that of the control group (P=0.021). The adverse events and complications included hemorrhage, perforation and esophageal stent displacement. No significant differences in adverse events and complications between the treatment group and the control group were observed. All patients were successfully treated during hospitalization. Effect of radiofrequency ablation combined with esophageal stent implantation was better than esophageal stent implantation in the treatment of malignant esophageal stenosis, but it had no effect on the survival time.

18.
Langmuir ; 34(26): 7681-7689, 2018 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-29860845

RESUMEN

Understanding the interaction of graphene with cell membranes is crucial to the development of graphene-based biological applications and the management of graphene safety issues. To help reveal the key factors controlling the interaction between graphene and cell membranes, here we adopt the dissipative particle dynamics method to analyze the evolution of interaction force and free energy as the graphene-covered atomic force microscopy (AFM) probe indents across a lipid bilayer. The simulation results show that the graphene-covered AFM probe can cause severe deformation of the cell membrane which drives the lipid molecule to adsorb and diffuse at the surface of graphene. The breakthrough force and free energy are calculated to study the effects of the tip shape, size, and surface hydrophobicity on the piercing behaviors of graphene-covered AFM. In addition, the deformation of cell membrane can decrease the dependency of the breakthrough force on the tip shape. The analysis of surface functionalization suggests that the horizontal patterns on graphene can change the preferred orientation in the penetration process, but the vertical patterns on graphene may disrupt the cell membrane. What's more, the bending stiffness of graphene has little influence on the penetration process as graphene pierces into the cell membrane. These results provide useful guidelines for the molecular design of graphene materials with controllable cell penetrability.

19.
Int J Med Sci ; 15(2): 142-152, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29333098

RESUMEN

Background: MicroRNAs (miRNAs) are non-coding small RNAs that function as negative regulators of gene expression and are involved in tumour biology. The eIF4E-binding proteins (eIF4EBPs) play essential roles in preventing translation initiation and inhibiting protein synthesis at a global or message-specific level in a variety of tumours. Methods: According to comparative miRNA profiles of clinical cervical cancer and non-cancerous cervical tissue specimens, several miRNAs were aberrantly expressed in the cervical cancer samples. C33a and SiHa cell proliferation and apoptosis were detected using methyl thiazolyl tetrazolium (MTT) and flow cytometry assays, respectively. Results: Among the aberrantly expressed miRNAs, miR-22-3p was significantly differentially expressed in cervical cancer tissues and was highly associated with cervical cancer cell growth regulation. In addition, bioinformatic predictions and experimental validation were used to identify whether eIF4E-binding protein 3 (eIF4EBP3) was a direct target of miR-22-3p; eIF4EBP3 protein levels were generally low in the cervical cancer tissues. Furthermore, functional studies revealed that either a miR-22-3p inhibitor or eIF4EBP3 overexpression could induce apoptosis in cervical cancer cells in vitro. Importantly, we found that eIF4EBP3 accumulation could significantly attenuate cervical cancer cell proliferation triggered by a miR-22-3p mimic as well as enhance apoptosis in cervical cancer cells. Conclusion: Taken together, our data provide primary proof that miR-22-3p can induce cervical cancer cell growth at least in part by up-regulating its expression to decrease eIF4EBP3 expression levels; miR-22-3p thus holds promise as a prognostic biomarker and potential therapeutic target for treating cervical cancer.


Asunto(s)
Carcinoma de Células Escamosas/patología , Proteínas Portadoras/genética , MicroARNs/genética , Neoplasias del Cuello Uterino/patología , Adulto , Apoptosis/genética , Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Proliferación Celular/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Persona de Mediana Edad , Neoplasias del Cuello Uterino/genética
20.
RSC Adv ; 8(2): 848-855, 2018 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-35539001

RESUMEN

Activated carbon (AC) is an environmentally sustainable oxygen reduction reaction (ORR) catalyst and widely used in MFCs due to its intrinsic high specific surface area and mesoporous characteristics, but it shows relatively high ORR over-potential thus low electrocatalytic activity. In this study, a method of doped carbon modification was employed to decrease the over-potential and improve the ORR electrocatalytic activity of the AC catalyst. Nitrogen and phosphorus co-doped carbon modified AC (NPC@AC) was prepared by coating phytic acid doped polyaniline onto AC through in situ oxidative polymerization and subsequent high-temperature pyrolysis. The as-prepared NPC@AC possessed a large surface area of ∼649.3 m2 g-1 inherited from AC and a low ORR over-potential with a highly positive onset potential of +0.22 V vs. Ag/AgCl from NPC, thus showing an enhanced ORR electrocatalytic activity in neutral solution compared to the pristine AC, and even better than the pure NPC. The air-cathode MFC using the NPC@AC catalyst generated a much higher open circuit voltage of 0.753 V and two times higher power density of 1223 mW m-2 than that using the pristine AC catalyst of about 0.432 V and 595 mW m-2, respectively.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...