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1.
J Neurosci Res ; 98(1): 201-211, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30895638

RESUMO

Approaches that facilitate the recovery from coma would have enormous impacts on patient outcomes and medical economics. Orexin-producing neurons release orexins (also known as hypocretins) energy-dependently to maintain arousal. Hyperbaric oxygen (HBO) could increase ATP levels by preserving mitochondrial function. We investigated, for the first time, the arousal effects of HBO and orexins mechanisms in a rat model of unconsciousness induced by ketamine or ethanol. A total of 120 Sprague-Dawley male rats were used in this study. Unconsciousness was induced either by intraperitoneal injection of ketamine or ethanol. The HBO treatment (100% O2 at 3 ATA) was administered immediately after unconsciousness induction for 1 hr. SB334867, orexin-1 receptor (OX1R) inhibitor, or JNJ10397049, orexin-2 receptor (OX2R) inhibitor was administered 30 min intraperitoneally before unconsciousness induction. Loss of righting reflex test (LORR) and Garcia test were used to evaluate the unconsciousness duration and neurological deficits after recovering from unconsciousness, respectively. Enzyme-linked immunosorbent assay was used to measure brain tissue ATP and orexin A levels. Ketamine or ethanol injection resulted in LORR immediately and neurological deficits 6 hr after unconsciousness induction. HBO treatment significantly reduced the LORR duration, improved Garcia scores and unregulated ATP and orexin A levels in the brain tissue. Administration of OX1R inhibitor or OX2 R inhibitor abolished arousal and neurological benefits of HBO. In conclusion, HBO exerted arousal-promoting effects on unconscious rats induced by ketamine or ethanol. The underlying mechanism was via, at least in part, ATP/orexin A upregulation. HBO may be a practical clinical approach to accelerate unconsciousness recovery in patients.

2.
J Neurosci Res ; 98(1): 129-140, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30916808

RESUMO

Age and severity are significant predictors of traumatic brain injury (TBI) outcomes in the immature brain. TBI studies have segregated TBI injury into three severity groups: mild, moderate, and severe. While mild TBI is most frequent form in children and adults, there is debate over the indicators used to denote mild injury. Clinically, magnetic resonance imaging (MRI) and computed tomography (CT) are used to diagnose the TBI severity when medically warranted. Herein, we induced mild, moderate, and severe TBI in juvenile rats (jTBI) using the controlled cortical impact model. We characterized the temporal and spatial injury after graded jTBI in vivo using high-field MRI at 0.25 (6 hr), 1 and 3 days post-injury (dpi) with comparative histology. Susceptibility-weighted imaging (SWI) for blood and T2-weighted imaging (T2WI) for edema were quantified over the 0.25-3 dpi. Edema volumes increased linearly with severity at 0.25 dpi that slowly continued to decrease over the 3 dpi. In contrast, blood volumes did not decrease over time. Mild TBI had the least amount of blood visible on SWI. Fluoro-jade B (FJB) staining for cell death confirmed increased cellular death with increasing severity and increased FJB + cells in the corpus callosum (CC). Interestingly, the strongest correlation was observed for cell death and the presence of extravascular blood. A clear understanding of acute brain injury (jTBI) and how blood/edema contribute to mild, moderate, and severe jTBI is needed prior to embarking on therapeutic interventions. Noninvasive imaging should be used in mild jTBI to verify lack of overt injury.

3.
Mil Med Res ; 6(1): 36, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31760944

RESUMO

BACKGROUND: Stable angina is one of the most common clinical types of coronary artery disease (CAD) and associated with poor health-related quality of life (HRQL). However, few studies have evaluated the risk factors associated with HRQL in patients with newly diagnosed stable angina. METHODS: A cross-sectional survey was conducted with 342 consecutive outpatients with newly diagnosed stable angina from October 2017 to January 2018 at the Second Affiliated Hospital of Army Medical University, Chongqing, China. Eight dimensions of HRQL were evaluated via the 36-item Short-Form Health Survey, including physical functioning, role limitation due to physical problems, bodily pain, general health, vitality, social functioning, role limitation due to emotional problems, and mental health. Physical and mental component summaries were calculated. Multiple stepwise regression was performed to determine the factors associated with HRQL. RESULTS: Patients who were older, were females, did not exercise, had lower educational levels, had lower monthly incomes, had smoking/drinking habits, and had diabetes, hypertension, or hyperlipemia showed lower physical HRQL scores, while those who were older with lower educational levels and lower monthly incomes showed lower mental HRQL scores. The results of the multiple stepwise regression analyses showed that physical and mental HRQL were positively correlated with exercise and monthly income and negatively associated with age. Patients with monthly income ≥5000 Yuan showed higher HRQL scores than those with monthly income < 5000 Yuan. Sleep quality and drinking were negatively associated with physical, but not mental HRQL. CONCLUSIONS: Our findings indicated that exercise and personal income level, both modifiable factors, were positively associated with physical and mental HRQL. These findings could have implications for clinical suggestions and strategies to improve HRQL in patients with stable angina.

4.
Eur Radiol ; 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31705256

RESUMO

OBJECTIVES: This study aimed to develop non-invasive machine learning classifiers for predicting post-Glenn shunt patients with low and high risks of a mean pulmonary arterial pressure (mPAP) > 15 mmHg based on preoperative cardiac computed tomography (CT). METHODS: This retrospective study included 96 patients with functional single ventricle who underwent a bidirectional Glenn procedure between November 1, 2009, and July, 31, 2017. All patients underwent post-procedure CT, followed by cardiac catheterization. Overall, 23 morphologic parameters were manually extracted from cardiac CT images for each patient. The Mann-Whitney U or chi-square test was applied to select the most significant predictors. Six machine learning algorithms including logistic regression, Naive Bayes, random forest (RF), linear discriminant analysis, support vector machine, and K-nearest neighbor were used for modeling. These algorithms were independently trained on 100 train-validation random splits with a 3:1 ratio. Their average performance was evaluated by area under the curve (AUC), accuracy, sensitivity, and specificity. RESULTS: Seven CT morphologic parameters were selected for modeling. RF obtained the best performance, with mean AUC of 0.840 (confidence interval [CI] 0.832-0.850) and 0.787 (95% CI 0.780-0.794); sensitivity of 0.815 (95% CI 0.797-0.833) and 0.778 (95% CI 0.767-0.788), specificity of 0.766 (95% CI 0.748-0.785) and 0.746 (95% CI 0.735-0.757); and accuracy of 0.782 (95% CI 0.771-0.793) and 0.756 (95% CI 0.748-0.764) in the training and validation cohorts, respectively. CONCLUSIONS: The CT-based RF model demonstrates a good performance in the prediction of mPAP, which may reduce the need for right heart catheterization in post-Glenn shunt patients with suspected mPAP > 15 mmHg. KEY POINTS: • Twenty-three candidate descriptors were manually extracted from cardiac computed tomography images, and seven of them were selected for subsequent modeling. • The random forest model presents the best predictive performance for pulmonary pressure among all methods. • The computed tomography-based machine learning model could predict post-Glenn shunt pulmonary pressure non-invasively.

5.
Opt Express ; 27(19): 26940-26956, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31674564

RESUMO

Stitching interferometry is performed by collecting interferometric data from overlapped sub-apertures and stitching these data together to provide a full surface map. The propagation of the systematic error in the measured subset data is one of the main error sources in stitching interferometry for accurate reconstruction of the surface topography. In this work, we propose, using the redundancy of the captured subset data, two types of two-dimensional (2D) self-calibration stitching algorithms to overcome this issue by in situ estimating the repeatable high-order additive systematic errors, especially for the application of measuring X-ray mirrors. The first algorithm, called CS short for "Calibrate, and then Stitch", calibrates the high-order terms of the reference by minimizing the de-tilted discrepancies of the overlapped subsets and then stitches the reference-subtracted subsets. The second algorithm, called SC short for "Stitch, and then Calibrate", stitches a temporarily result and then calibrates the reference from the de-tilted discrepancies of the measured subsets and the temporarily stitched result. In the implementation of 2D scans in x- and y-directions, step randomization is introduced to generate nonuniformly spaced subsets which can diminish the periodic stitching errors commonly observed in evenly spaced subsets. The regularization on low-order terms enables a highly flexible option to add the curvature and twist acquired by another system. Both numerical simulations and experiments are carried out to verify the proposed method. All the results indicate that 2D high-order repeatable additive systematic errors can be retrieved from the 2D redundant overlapped data in stitching interferometry.

6.
Food Chem Toxicol ; : 110921, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31669597

RESUMO

Determining chemical carcinogenicity in the early stages of drug discovery is fundamentally important to prevent the adverse effect of carcinogens on human health. There has been a recent surge of interest in developing computational approaches to predict chemical carcinogenicity. However, the predictive power of many existing approaches is limited, and there is plenty of room for improvement. Here, we develop a new deep learning architecture, termed CapsCarcino, to distinguish between carcinogens and noncarcinogens. CapsCarcino is constructed based on a dynamic routing algorithm that requires less data, extracts more comprehensive information, and does not require feature selection. We find that CapsCarcino provides a significantly improved predictive and generalization ability over, and outperforms five other machine learning models. Specifically, the best model of CapsCarcino achieves an accuracy of 85.0% on an external validation dataset. In addition, we discover that the enhanced predictive capability of CapsCarcino over that of the other methods is robust and can be achieved using sparse datasets. Training on merely 20% of the dataset, CapsCarcino performs comparably to the other methods based on the full training dataset. Further mechanism analysis indicates that CapsCarcino could efficiently learn the characteristics of carcinogens even if structural alerts are insufficiently represented. The results indicate that CapsCarcino should be helpful for carcinogen risk assessment.

7.
Medicine (Baltimore) ; 98(45): e17913, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31702669

RESUMO

Nocardia is an opportunistic pathogen from environment, which is generally thought to infect immunosuppressed patients (ISPs), but recent studies showed it could also cause infections in immunocompetent patients (ICPs).The aim of this study was to compare the clinical characteristics, patients' outcome, Nocardia species' identification, and antibiotic susceptibility profiles of nocardiosis between ICPs and ISPs.The detailed clinical data were collected from all the nonrepetitive nocardiosis patients during 2011 and 2018, from a tertiary general hospital in Beijing, China. Then each Nocardia isolate was identified to species level by DNA sequencing. The antibiotic susceptibility testing was performed by E test method, and interpreted following CLSI M24 document. The clinical and microbiological characteristics between ICPs and ISPs were compared statistically.A total of 23 nonrepetitive nocardiosis patients with detailed clinical data were enrolled in this study. Among them, 9 were ICPs and 14 were ISPs. All the skin and soft tissue infections occurred in ICPs (33.3% vs 0%, P < .05). Bronchiectasis occurred more frequently in ICPs (44.4% vs 21.4%), whereas chronic kidney diseases and coinfection with aspergillosis occurred more frequently in ISPs (35.7% vs 0%, 35.7% vs 0%, respectively), although they did not reach the statistical significance. There were no significant differences in other clinical characteristics, Nocardia species' identification, and antibiotic susceptibility between ISPs and ICPs (P > .05).Nocardiosis could occur in both ISPs and ICPs. Skin and soft tissue infection and bronchiectasis occurred more frequently in ICPs. Chronic kidney diseases and co-infection with aspergillosis occurred more frequently in ISPs. These characteristics should be noticed by physicians in diagnosis of nocardiosis.


Assuntos
Imunocompetência , Nocardiose/microbiologia , Nocardia/isolamento & purificação , Adulto , Idoso , Antibacterianos/uso terapêutico , China/epidemiologia , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana/estatística & dados numéricos , Pessoa de Meia-Idade , Nocardia/efeitos dos fármacos , Nocardiose/classificação , Nocardiose/diagnóstico , Nocardiose/epidemiologia , Estudos Retrospectivos , Centros de Atenção Terciária/estatística & dados numéricos
8.
Cardiol Young ; : 1-4, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31771665

RESUMO

OBJECTIVE: To study the incidence, types, and characteristics of CHD in all live births delivered in Jinshan Hospital from 1 January, 2016 to 31 December, 2017, and to analyse the correlation between CHD and the distance between maternal residence and Shanghai Petrochemical Complex. METHODS: All live births, delivered in Jinshan Hospital in 2016 and 2017, have received CHD screening and neonatal follow-up after delivery. For those both positive for CHD screening and negative for CHD screening but with heart murmur found during physical examination on neonatal follow-up after delivery, echocardiography was performed to confirm CHD diagnosis. All maternal residential addresses have been grouped for analysis according to the distance between maternal residence and Shanghai Petrochemical Complex. RESULTS: There were 5544 live births in total, and a total of 79 children with CHD were confirmed by CHD screening and echocardiography, of which the types of diseases with high incidence, in descending order of incidence, are atrial septal defect (48/79), ventricular septal defect (25/79), patent ductus arteriosus (21/79), and pulmonary artery stenosis (9/79). There was no statistically significant difference in the incidence of CHD among the groups divided by the distance between maternal residence and Shanghai Petrochemical Complex. The incidence of neonatal CHD near Shanghai Petrochemical Complex is 1.42%. CONCLUSIONS: Most of the children with CHD can be screened out through CHD screening and physical examination in neonatal period and early infancy stage. The distance between maternal residence and Shanghai Petrochemical Complex has no significant direct effect on the incidence of CHD in neonates near Shanghai Petrochemical Complex.

9.
Artigo em Inglês | MEDLINE | ID: mdl-31776608

RESUMO

25-hydroxyvitamin D3 has attracted considerable attention due to its great medical value and huge market demand in animal husbandry. Microbial production of 25-hydroxyvitamin D3 has been recognized as an alternative superior to traditional chemical synthesis. In this study, a Gram-positive bacteria zju 4-2 (CCTCC M 2019385) was isolated from the soil using vitamin D3 as the sole carbon source and was identified as Bacillus cereus according to its physiological characteristics and 16S rRNA analysis, which also showed a relatively high capacity for 25-hydroxyvitamin D3 production. Through systematic optimization of different catalytic conditions, the optimal solvent system of vitamin D3, vitamin D3 addition time and concentration, temperature, and pH were shown to be propylene glycol/ethanol (v/v = 9:1), early stationary phase, 2 g/L, 37 °C, and pH 7.2, respectively. With these optimal conditions, 796 mg/L of 25-hydroxyvitamin D3 was achieved after 48 h bioconversion with zju 4-2 at the shake flask level. Finally, up to 830 mg/L 25-hydroxyvitamin D3 with a yield of 41.5% was obtained in a 5 L fermentation tank. Our developed biotransformation process with this newly isolated strain provides a platform to produce 25-hydroxyvitamin D3 efficiently at industrialization scale.

10.
Stat Med ; 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31777978

RESUMO

Models for the ordered multiple categorical (OMC) response variable have already been extensively established and widely applied, but few studies have investigated linear regression problems with OMC predictors, especially in high-dimensional situations. In such settings, the pseudocategories of the discrete variable and other irrelevant explanatory variables need to be automatically selected. This paper introduces a transformation method of dummy variables for such OMC predictors, an L1 penalty regression method is proposed based on the transformation. Model selection consistency of the proposed method is derived under some common assumptions for high-dimensional situation. Both simulation studies and real data analysis present good performance of this method, showing its wide applicability in relevant regression analysis.

11.
Forensic Sci Int Genet ; 44: 102169, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614310

RESUMO

Short tandem repeat within the male-specific part of the human Y chromosome (Y-STR) is an effective forensic tool in mixture identification, patrilineal relationship evaluation, and familial searches. Despite their usefulness, current Y-STR-based genotyping systems often lack the discriminatory power to resolve genetic relationships between distant relatives or within patrilocal populations. In this study, we developed a novel Y-STR 29-plex typing system, which combined the 17 Y-STR loci used in the AmpFLSTR® Yfiler® PCR Amplification Kit (Yfiler), eight Y-STR loci with a low-medium mutation rate, and four rapidly mutating Y-STR loci. The system was generated to achieve greater discriminatory power between male subjects and improved ability to infer haplogroup classifications. The system was extensively tested on data from 752 individuals for its sensitivity, male specificity, species specificity, mixture resolution, reproducibility, concordance, stutter and size accuracy, precision, and population genetics, following the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. The results demonstrated that the Y-STR 29-plex typing system was time-efficient, reproducible, accurate, sensitive, and robust to familial searching and paternal biogeographic ancestry inference.

12.
Cancer Immunol Res ; 7(12): 2065-2073, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31615816

RESUMO

Current gastric cancer staging alone cannot predict prognosis and adjuvant chemotherapy benefits in stage II and III gastric cancer. Tumor immune microenvironment biomarkers and tumor-cell chemosensitivity might add predictive value to staging. This study aimed to construct a predictive signature integrating tumor immune microenvironment and chemosensitivity-related features to improve the prediction of survival and adjuvant chemotherapy benefits in patients with stage II to III gastric cancer. We used IHC to assess 26 features related to tumor, stroma, and chemosensitivity in tumors from 223 patients and evaluated the association of the features with disease-free survival (DFS) and overall survival (OS). Support vector machine (SVM)-based methods were used to develop the predictive signature, which we call the SVM signature. Validation of the signature was performed in two independent cohorts of 445 patients. The diagnostic signature integrated seven features: CD3+ cells at the invasive margin (CD3 IM), CD8+ cells at the IM (CD8 IM), CD45RO+ cells in the center of tumors (CD45RO CT), CD66b+ cells at the IM (CD66b IM), CD34+ cells, periostin, and cyclooxygenase-2. Patients fell into low- and high-SVM groups with significant differences in 5-year DFS and OS in the training and validation cohorts (all P < 0.001). The signature was an independent prognosis indicator in multivariate analysis in each cohort. The signature had better prognostic value than various clinicopathologic risk factors and single features. High-SVM patients exhibited a favorable response to adjuvant chemotherapy. Thus, this SVM signature predicted survival and has the potential for identifying patients with stage II and III gastric cancer who could benefit from adjuvant chemotherapy.

14.
Medicine (Baltimore) ; 98(43): e17705, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31651902

RESUMO

BACKGROUND: The aim of this meta-analysis is to investigate the impact of Osimertinib on treatment efficacy in advanced nonsmall cell lung cancer (NSCLC). METHODS: Trials comparing Osimertinib against epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)/chemotherapy in patients with NSCLC with an epidermal growth factor receptor (EGFR) mutation were included, and the pooled data for progression-free survival (PFS), overall survival (OS), overall response rate (ORR), disease control rate (DCR), and adverse events (AEs) were analyzed. RESULTS: Analysis results based on 6 eligible trials showed that Osimertinib significantly improved the overall PFS (hazard ratio [HR] = 0.38, 95% confidence interval [CI] = 0.29-0.50), improved the OS (HR = 0.66, 95% CI = 0.48-0.89), increased the ORR (odds ratio [OR] = 1.76, 95% CI = 1.14-2.72), increased the overall DCR (OR = 1.18, 95% CI = 1.02-1.37), and reduced the grade 3 or greater AEs (relative ratio [RR] = 0.50, 95% CI = 0.33-0.75) in all subgroups except in the ORR in the Exon 19 deletion (Ex19del) and/or L858R subgroup. Compared to patients with Ex19del and/or L858R mutation, patients with the T790M mutation had the benefits of a greater PFS (41.7%), a greater ORR (80.0%), a greater DCR (71.2%), and fewer grade 3 or greater AEs (70.7%) (each P < .05). Race, sex, age, EGFR mutation, and smoking history may significantly predict additional benefits from Osimertinib, but there were no significant differences between subgroups stratified by these clinical characteristics. CONCLUSIONS: Osimertinib showed greater treatment benefit for patients with NSCLC with EGFR mutation than EGFR-TKIs/chemotherapy, especially for T790M mutation-positive patients.


Assuntos
Acrilamidas/uso terapêutico , Compostos de Anilina/uso terapêutico , Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Inibidores de Proteínas Quinases/uso terapêutico , Receptores ErbB/genética , Humanos , Mutação
15.
Appl Microbiol Biotechnol ; 103(21-22): 8911-8922, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31583448

RESUMO

Corynebacterium glutamicum is a versatile workhorse for producing industrially important commodities. The design of an optimal strain often requires the manipulation of metabolic and regulatory genes to different levels, such as overexpression, downregulation, and deletion. Unfortunately, few tools to achieve multiple functions simultaneously have been reported. Here, a dual-functional clustered regularly interspaced short palindromic repeats (CRISPR) (RE-CRISPR) system that combined genome editing and transcriptional repression was designed using a catalytically active Cas12a (a.k.a. Cpf1) in C. glutamicum. Firstly, gene deletion was achieved using Cas12a under a constitutive promoter. Then, via engineering of the guide RNA sequences, transcriptional repression was successfully achieved using a catalytically active Cas12a with crRNAs containing 15 or 16 bp spacer sequences, whose gene repression efficiency was comparable to that of the canonical system (deactivated Cas12a with full-length crRNAs). Finally, RE-CRISPR was developed to achieve genome editing and transcriptional repression simultaneously by transforming a single crRNA plasmid and Cas12a plasmid. The application of RE-CRISPR was demonstrated to increase the production of cysteine and serine for ~ 3.7-fold and 2.5-fold, respectively, in a single step. This study expands the application of CRISPR/Cas12a-based genome engineering and provides a powerful synthetic biology tool for multiplex metabolic engineering of C. glutamicum.

16.
Spectrochim Acta A Mol Biomol Spectrosc ; 225: 117598, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31605939

RESUMO

Silver nanoarrays were fabricated by inkjet printing silver nanoparticles ink on the gratings of compact disc recordable (CD-R). Rhodamine 6G (R6G) was chosen as a probe molecule to evaluate their surface-enhanced Raman scattering (SERS) performance. The finite-difference time domain (FDTD) solution was used to simulate local electric field distribution of silver nanoparticles on the grating surface and flat surface, respectively. It was found that the Ag/grating substrate possessed higher enhancement ability than the Ag/flat due to the high-density hot spots of periodic structure of the grating. The silver nanoarrays substrate exhibited high stability and the characteristic peaks of R6G can be still well observed after eight months. The substrate also exhibited a good spot-to-spot reproducibility with an RSD of 10.21% by eight points. SERS mappings of R6G adsorbed on silver nanoarrays were tested under the ultra-fast Raman imaging mode, and the relative standard deviation (RSD) values of uniformity were calculated to be 8.35% and 11.53% at 610 cm-1 band measured by 2500 and 6480 points, respectively. In addition, the as-prepared silver nanoarrays was successfully applied to the detection of melamine in adult milk powder solution directly. A good linear relationship with the correlation coefficient of 0.9968 between peak intensity and concentration was obtained from 1.2 to 100 mg/L.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31635357

RESUMO

In this study, we applied an integrated approach to an ecological risk evaluation of heavy metal pollution in industrial and mining wastelands in Yangxin County, China. A total of 72 sampling sites were designated in the study area. The results show that the potential ecological risk levels of Hg and Cd are higher, and the coefficient of variation of mercury levels is large. Cr, Cu, Zn, Pb, Ni, and As are all at low potential ecological risk. The land types with relatively high ecological risks are alum and coal mines. In the soil of alum mines, the risk due to mercury is higher, while in coal mine soil, the risk due to cadmium is relatively higher.

18.
Chembiochem ; 2019 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-31605652

RESUMO

The use of oxidoreductases (EC1) in non-conventional reaction media has been increasingly explored. Especially, deep eutectic solvents (DESs) have emerged as novel class of solvents. Here we present an in-depth study of a bioreduction with an alcohol dehydrogenase (ADH) in the DES glyceline. The activity and stability of ADH in glyceline-water mixtures using varying water contents were measured. Furthermore, the thermodynamic water activity and viscosity of glyceline-water mixtures have been determined. For a better understanding of the observations molecular dynamics (MD) simulations were carried out to quantify ADH's molecular flexibility, hydration layer, and intra-protein hydrogen bonds. The behavior of the enzyme in DES follows the classic dependence of water activity (aW) in non-conventional media. At low aW values (< 0.2) ADH does not show any activity, at higher aW values the activity was still lower than in pure water due to the high viscosities of the DES. These findings could be further explained by an increased enzyme flexibility with increased water content.

19.
J Hazard Mater ; : 121373, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31607582

RESUMO

In this paper, Ce-AlOOH were investigated to develop as an adsorbent for removing fluoride. Oxalic acid was selected as an effectively modified reagent to improve the performance of adsorption. Cerium existed in the form of CeO2 and kept good stability during the adsorption process through XRD, TEM, BET, Raman, and Infrared spectra. The adsorption capacity could be improved with the addition of cerium (62.8 mg/g). Specially, the oxalic acid modification significantly promoted the adsorption capacity to 90 mg/g. There adsorption isotherm and kinetics were estimated independently. These adsorption behaviors were in accordance with the Freundlich model and pseudo-second-order model, indicating that chemisorption was the rate-determining step. the obtained adsorbents all exhibited good recycling performance using oxalic acid as the regeneration reagent. The species of tetravalent cerium was the important adsorption sites. The mechanism was carefully explored by XPS analysis. The fluoride adsorption process can be ascribed to the combined effect of the electrostatic action, surface coordination, and ion exchange between M-OH and F-. Furthermore, modification of oxalic acid exhibited a new easier way to quickly increase M-OH content, which contributed to the dominated adsorption sites.

20.
J Chromatogr Sci ; 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31609449

RESUMO

We established an efficient method using high-speed counter-current chromatography (HSCCC) combined with preparative high-performance liquid chromatography (prep-HPLC) for isolating and purifying phenolic glycoside isomers. The method involves a rapid and sensitive ultra-performance liquid chromatography-under voltage(UPLC-UV) technique using a sub-2 µm core-shell particle column for qualitative and quantitative analysis of four phenolic glycoside isomers from Idesia polycarpa Maxim. leaves. The partially purified samples from ethyl acetate extraction of ethanol extracts of I. polycarpa Maxim. leaves were obtained by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water solution (3:5:3:5, v/v/v/v) to obtain fractions I and II, which contain two phenolic glycoside isomers. The two fractions were further isolated by prep-HPLC to yield compounds 1, 2, 3, and 4 with purities of 98.29%, 98.71%, 98.49% and 98.52%, and total recoveries of 93.5%, 72.2%, 75.5% and 88.3%, respectively. Compound 1 was first isolated from I. polycarpa Maxim., while compound 2 was reported to be a new phenolic glycoside, which is 1-[(6'-O-(Z)-p-coumaroyl)-ß-D-glucopyranosyl]-oxy-2-phenol. The chemical structures of the four phenolic glycoside isomers were analyzed and confirmed by UPLC, UV, electrospray ionization mass spectrometry (ESI-MS), fourier transform infra-red (FT-IR), 1H-nuclear magnetic resonance (1H NMR), 13C-nuclear magnetic resonance (13C NMR) and 2D nuclear magnetic resonance (2D NMR) spectra. This study opens prospects for broad industrial applications of HSCCC/prep-HPLC for the isolation and purification of isomers.

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