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1.
JMIR Mhealth Uhealth ; 9(9): e24402, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34473067

RESUMO

BACKGROUND: For rehabilitation training systems, it is essential to automatically record and recognize exercises, especially when more than one type of exercise is performed without a predefined sequence. Most motion recognition methods are based on feature engineering and machine learning algorithms. Time-domain and frequency-domain features are extracted from original time series data collected by sensor nodes. For high-dimensional data, feature selection plays an important role in improving the performance of motion recognition. Existing feature selection methods can be categorized into filter and wrapper methods. Wrapper methods usually achieve better performance than filter methods; however, in most cases, they are computationally intensive, and the feature subset obtained is usually optimized only for the specific learning algorithm. OBJECTIVE: This study aimed to provide a feature selection method for motion recognition of upper-limb exercises and improve the recognition performance. METHODS: Motion data from 5 types of upper-limb exercises performed by 21 participants were collected by a customized inertial measurement unit (IMU) node. A total of 60 time-domain and frequency-domain features were extracted from the original sensor data. A hybrid feature selection method by combining filter and wrapper methods (FESCOM) was proposed to eliminate irrelevant features for motion recognition of upper-limb exercises. In the filter stage, candidate features were first selected from the original feature set according to the significance for motion recognition. In the wrapper stage, k-nearest neighbors (kNN), Naïve Bayes (NB), and random forest (RF) were evaluated as the wrapping components to further refine the features from the candidate feature set. The performance of the proposed FESCOM method was verified using experiments on motion recognition of upper-limb exercises and compared with the traditional wrapper method. RESULTS: Using kNN, NB, and RF as the wrapping components, the classification error rates of the proposed FESCOM method were 1.7%, 8.9%, and 7.4%, respectively, and the feature selection time in each iteration was 13 seconds, 71 seconds, and 541 seconds, respectively. CONCLUSIONS: The experimental results demonstrated that, in the case of 5 motion types performed by 21 healthy participants, the proposed FESCOM method using kNN and NB as the wrapping components achieved better recognition performance than the traditional wrapper method. The FESCOM method dramatically reduces the search time in the feature selection process. The results also demonstrated that the optimal number of features depends on the classifier. This approach serves to improve feature selection and classification algorithm selection for upper-limb motion recognition based on wearable sensor data, which can be extended to motion recognition of more motion types and participants.

2.
J Healthc Eng ; 2021: 9930543, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34394900

RESUMO

Cold pathogenic disease is a widespread disease in traditional Chinese medicine, which includes influenza and respiratory infection associated with high incidence and mortality. Discovering effective core drugs in Chinese medicine prescriptions for treating the disease and reducing patients' symptoms has attracted great interest. In this paper, we explore the core drugs for curing various syndromes of cold pathogenic disease from large-scale literature. We propose a core drug discovery framework incorporating word embedding and community detection algorithms, which contains three parts: disease corpus construction, drug network generation, and core drug discovery. First, disease corpus is established by collecting and preprocessing large-scale literature about the Chinese medicine treatment of cold pathogenic disease from China National Knowledge Infrastructure. Second, we adopt the Chinese word embedding model SSP2VEC for mining the drug implication implied in the literature; then, a drug network is established by the semantic similarity among drugs. Third, the community detection method COPRA based on label propagation is adopted to reveal drug communities and identify core drugs in the drug network. We compute the community size, closeness centrality, and degree distributions of the drug network to analyse the patterns of core drugs. We acquire 4681 literature from China national knowledge infrastructure. Twelve significant drug communities are discovered, in which the top-10 drugs in every drug community are recognized as core drugs with high accuracy, and four classical prescriptions for treating different syndromes of cold pathogenic disease are discovered. The proposed framework can identify effective core drugs for curing cold pathogenic disease, and the research can help doctors to verify the compatibility laws of Chinese medicine prescriptions.

3.
J Mol Model ; 27(8): 228, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34291349

RESUMO

The O(3P)-initiated conversion mechanism and dynamics of CH3CHCO were researched in atmosphere by executing density functional theory (DFT) computations. Optimizations of all the species and single-point energy computations were implemented at the B3LYP/6-311++G(d,p) and CCSD(T)/cc-pVTZ level, respectively. The explicit oxidation mechanism was introduced and discussed. The results state clearly that the O(3P) association was more energetically beneficial than the abstraction of H. The rate coefficients over the probable temperature range of 200-3000 K were forecasted by implementing Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Specifically, the total rate coefficient of O(3P) association reactions is 1.19 × 10-11 cm3 molecule-1 s-1 at 298 K, which is consistent with the experimental results (1.16 × 10-11 cm3 molecule-1 s-1). The rate coefficients for the O(3P) with CH2CO, CH3CHCO, and (CH3)2CCO suggest that rate coefficient of ketene derivatives increase with the increase of methylation degree. Graphical abstract.

4.
J Org Chem ; 86(7): 4932-4943, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33730490

RESUMO

A convenient preparation method of N-acylbenzoxazines has been developed, in which phenols react with nitriles and dimethyl sulfoxide (DMSO) in the presence of a catalytic amount of (COCl)2 in CH3CN or chloroform to afford the corresponding N-acylbenzoxazines in moderate-to-good yields. DMSO acts as a source of HCHO, which is generated in situ from the decomposition of a methoxydimethylsulfonium salt. A regeneration cycle of the methoxydimethylsulfonium salt is proposed, which is initiated by a catalytic amount of (COCl)2.


Assuntos
Dimetil Sulfóxido , Fenóis , Catálise , Clorofórmio , Nitrilas
5.
BMC Complement Med Ther ; 21(1): 23, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413354

RESUMO

BACKGROUND: Evidence showed that Tai Chi may have beneficial effects among hypertensive individuals, although the results are not convincing. We aim to conduct a high-quality clinical trial with 24-h BP measurement to provide robust evidence of Tai Chi for essential hypertension. METHODS: This is an open-label single-center randomized controlled trial with 3 parallel arms. We will compare Tai Chi with walking and waiting-list control. We will recruit 234 hypertensive patients with mild to moderate essential hypertension and randomly assign them to 3 different groups. Participants in Tai Chi group will receive a group-format Yang style 24-form Tai Chi exercise program, 3 sessions per week for 12 weeks. The walking group will be asked to walk, 3 sessions per week for 12 weeks. The waiting-list group will not receive any interventions and/or exercise training. The primary outcome is the change in average 24-h systolic blood pressure (SBP) between baseline and 12 weeks after randomization. The secondary outcomes include 24-h Diastolic Blood Pressure (DBP), average SBP and average DBP during the daytime and night-time, blood pressure (BP) variability, SBP load and DBP load, circadian rhythm of BP, and morning BP surge, endothelial functional indicators, home measured BP, quality of life, adverse events and so on. DISCUSSION: We expect findings of this trial will provide important insight into application of Tai Chi as an effective and acceptable method for hypertensive patients. Successful completion of this proposed study will also contribute to promotion of Tai Chi in the community in the future. TRIAL REGISTRATION: Clinicaltrials.gov registry: https://clinicaltrials.gov/ct2/show/NCT04267471 , date: February 12, 2020.


Assuntos
Hipertensão Essencial/terapia , Tai Ji , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea , Humanos , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Caminhada
6.
Int J Biol Macromol ; 168: 656-662, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-33220369

RESUMO

Moisture and amylose are important factors affecting the quality of heat-treated starches. The amylose content in heat-treated rice starch increased as moisture content (MC) increased from 8% to 30%, but decreased at MC of 70%. With the increase of MC, the paste transmittance, gelatinization temperature, and digestibility of starch increased, whereas the swelling power and enthalpy decreased. The long- and short-range molecular order and the digestive properties of starch with MC ≤ 30% changed moderately, but high MC (70%) gelatinized the starch and drastically changed the physicochemical properties. High amylose content in rice starch led to low long- and short-range molecular order, swelling power, and gelatinization temperature, but increased resistant starch. The results indicated that 30% of MC separates effects of heat treatment of starch, where low MC (≤30%) and high amylose lowers digestibility, which is beneficial for diabetics, while high MC (>30%) promotes solubility and transparency.


Assuntos
Amilose/química , Oryza/química , Amido/química , Temperatura Alta , Solubilidade , Difração de Raios X
7.
IEEE J Biomed Health Inform ; 25(7): 2820-2832, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33373310

RESUMO

Adverse drug-drug interaction (ADDI) becomes a significant threat to public health. Despite the detection of ADDIs is experimentally implemented in the early development phase of drug design, many potential ADDIs are still clinically explored by accidents, leading to a large number of morbidity and mortality. Several computational models are designed for ADDI prediction. However, they take no consideration of drug dependency, although many drugs usually produce synergistic effects and own highly mutual dependency in treatments, which contains underlying information about ADDIs and benefits ADDI prediction. In this paper, we design a dependent network to model the drug dependency and propose an attribute supervised learning model Probabilistic Dependent Matrix Tri-Factorization (PDMTF) for ADDI prediction. In particular, PDMTF incorporates two drug attributes, molecular structure and side effect, and their correlation to model the adverse interactions among drugs. The dependent network is represented by a dependent matrix, which is first formulated by the row precision matrix of the predicted attribute matrices and then regularized by the molecular structure similarities among drugs. Meanwhile, an efficient alternating algorithm is designed for solving the optimization problem of PDMTF. Experiments demonstrate the superior performance of the proposed model when compared with eight baselines and its two variants.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Preparações Farmacêuticas , Algoritmos , Interações Medicamentosas , Humanos , Modelos Estatísticos
8.
Comput Math Methods Med ; 2020: 1862168, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32952598

RESUMO

The Traditional Chinese Medicine (TCM) formula is the main treatment method of TCM. A formula often contains multiple herbs where core herbs play a critical therapeutic effect for treating diseases. It is of great significance to find out the core herbs in formulae for providing evidences and references for the clinical application of Chinese herbs and formulae. In this paper, we propose a core herb discovery model CHDSC based on semantic analysis and community detection to discover the core herbs for treating a certain disease from large-scale literature, which includes three stages: corpus construction, herb network establishment, and core herb discovery. In CHDSC, two artificial intelligence modules are used, where the Chinese word embedding algorithm ESSP2VEC is designed to analyse the semantics of herbs in Chinese literature based on the stroke, structure, and pinyin features of Chinese characters, and the label propagation-based algorithm LILPA is adopted to detect herb communities and core herbs in the herbal semantic network constructed from large-scale literature. To validate the proposed model, we choose chronic glomerulonephritis (CGN) as an example, search 1126 articles about how to treat CGN in TCM from the China National Knowledge Infrastructure (CNKI), and apply CHDSC to analyse the collected literature. Experimental results reveal that CHDSC discovers three major herb communities and eighteen core herbs for treating different CGN syndromes with high accuracy. The community size, degree, and closeness centrality distributions of the herb network are analysed to mine the laws of core herbs. As a result, we can observe that core herbs mainly exist in the communities with more than 25 herbs. The degree and closeness centrality of core herb nodes concentrate on the range of [15, 40] and [0.25, 0.45], respectively. Thus, semantic analysis and community detection are helpful for mining effective core herbs for treating a certain disease from large-scale literature.


Assuntos
Descoberta de Drogas/métodos , Medicamentos de Ervas Chinesas/classificação , Medicamentos de Ervas Chinesas/uso terapêutico , Glomerulonefrite/tratamento farmacológico , Fitoterapia , Algoritmos , Inteligência Artificial , China , Doença Crônica , Biologia Computacional , Mineração de Dados , Bases de Dados de Produtos Farmacêuticos , Descoberta de Drogas/estatística & dados numéricos , Humanos , Conceitos Matemáticos , Medicina Tradicional Chinesa/métodos , Medicina Tradicional Chinesa/estatística & dados numéricos , Semântica
9.
Polymers (Basel) ; 12(8)2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32751822

RESUMO

This work examined the effect of ultrasound and microwave treatments, separate and in combination, on the physicochemical and functional properties of chestnut starch. The results revealed that the ultrasonic-microwave (UM) and microwave-ultrasonic (MU) dually modified samples exhibited more severe surface damage, weaker birefringence, and lower relative crystallinity and gelatinization enthalpy than the native and single-treated starches. The UM samples showed the highest oil absorption capacity, and the MU samples showed the highest water absorption capacity and the best freeze-thaw stability (five cycles) among all samples. The swelling power, peak, trough, final, and breakdown viscosities, and pasting temperature all decreased regardless of single or dual modification. This study provides a reference for potential industrial applications of ultrasound and microwave treatments for the modification of chestnut starch.

10.
Plants (Basel) ; 9(4)2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32230740

RESUMO

Triterpenoid compounds are one of the main functional components in jujube fruit. In this study, the optimal process for ultrasound-assisted extraction (UAE) of total triterpenoids from jujube fruit was determined using response surface methodology (RSM). The optimal conditions were as follows: temperature of 55.14 °C, ethanol concentration of 86.57%, time of 34.41 min, and liquid-to-solid ratio of 39.33 mL/g. The triterpenoid yield was 19.21 ± 0.25 mg/g under optimal conditions. The triterpenoid profiles and antioxidant activity were further analyzed. Betulinic acid, alphitolic acid, maslinic acid, oleanolic acid, and ursolic acid were the dominant triterpenoid acids in jujube fruits. Correlation analysis revealed a significant positive correlation between the major triterpenic acids and antioxidant activities. The variations of triterpenoid profiles and antioxidant activity within the jujube fruits and the degree of variation were evaluated by hierarchical cluster analysis (HCA) and principal component analysis (PCA), respectively. The results provide important guidance for the quality evaluation and industrial application of jujube fruit.

11.
Food Chem ; 321: 126687, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32244138

RESUMO

The effect of food processing on the level and fate of chiral pesticide residues in apple products has rarely been investigated. In this study, we used ultra-performance convergence chromatography coupled with triple quadrupole mass spectrometry to determine the content of the novel chiral acaricide cyflumetofen. The matrix-matched calibration lines were constructed for apple slices, juice, wine and vinegar, and the determination coefficients (r2) exceeded 0.9954. Acceptable average recoveries were within 81.1% to 119.9%, and the relative standard deviations (RSDs) ranged from 0.8% to 11.0%. Processing effectiveness is represented by the processing factor (PF). The results indicated that the PFs of different procedures (washing, peeling, enzymolysis, fermentation, among others.) were generally less than 1. The reduction of cyflumetofen enantiomers during fermentation was in accordance with first-order kinetics, and stereoselective behavior was observed. This study provides reliable references for the risk assessment of cyflumetofen in the processing of apple products.


Assuntos
Malus/química , Resíduos de Praguicidas/química , Propionatos/química , Acaricidas/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Estereoisomerismo
12.
J Lipid Res ; 61(4): 560-569, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32029512

RESUMO

This article focuses on the establishment of an accurate and sensitive quantitation method for the analysis of furan fatty acids. In particular, the sensitivity of GC/MS and UPLC/ESI/MS/MS was compared for the identification and quantification of furan fatty acids. Different methylation methods were tested with respect to GC/MS analysis. Special attention needs to be paid to the methylation of furan fatty acids, as acidic catalysts might lead to the degradation of the furan ring. GC/MS analysis in full-scan mode demonstrated that the limit of quantitation was 10 µM. UPLC/ESI/MS/MS in multiple reaction monitoring mode displayed a higher detection sensitivity than GC/MS. Moreover, the identification of furan fatty acids with charge-reversal derivatization was tested in the positive mode with two widely used pyridinium salts. Significant oxidation was unexpectedly observed using N-(4-aminomethylphenyl) pyridinium as a derivatization agent. The formed 3-acyl-oxymethyl-1-methylpyridinium iodide derivatized by 2-bromo-1-methylpyridinium iodide and 3-carbinol-1-methylpyridinium iodide improved the sensitivity more than 2,000-fold compared with nonderivatization in the negative mode by UPLC/ESI/MS/MS. This charge-reversal derivatization enabled the targeted quantitation of furan fatty acids in human plasma. Thus, it is anticipated that this protocol could greatly contribute to the clarification of pathological mechanisms related to furan fatty acids and their metabolites.

14.
Medicine (Baltimore) ; 98(46): e17929, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31725646

RESUMO

BACKGROUND: Upper limb dysfunction is one of common sequelae of stroke which limits daily activities and decreases quality of life of patients, as well as increasing caregiving burden on families. Theta burst stimulation (TBS) is considered to be a beneficial therapy for post-stroke patients with upper limb motor dysfunction, but there is a lack of a high quality evidence. We aim to investigate the effectiveness and safety of TBS for upper limb motor dysfunction in patients with stroke. METHODS: The following databases will be searched: PubMed, EMBASE, The Cochrane Library, Web of Science, China Biology Medicine (CBM), China National Knowledge infrastructure (CNKI), Technology Periodical Database (VIP) and WanFang Data from the inception to October 2019. All relevant randomized controlled trials (RCTs) using TBS to treat poststroke patients with upper limb motor dysfunction will be included. The primary outcome is Upper Limb Fugl-Meyer Assessment (UL-FMA). Secondary outcomes will include Action Research Arm Test (ARAT), Box and Block Test (BBT), Wolf Motor Function Test (WMFT), Motor Assessment Scale (MAS), Nine Hole Peg Test (NHPT), Grip strength and other scales evaluating the upper limb motor function. Adverse effects will also be evaluated. Two reviewers will screen studies, extract data and assess the risk of bias of included studies independently. Data analysis will be conducted using Review Manager software (RevMan, version 5.3.5) and R software (version 3.6.1). RESULTS: Our SR will be conducted according to AMSTAR 2.0 and reported in compliance with PRISMA. The findings of this SR will be disseminated through peer-reviewed publications or conference presentations. CONCLUSION: Our study will provide evidence for the effectiveness and safety of theta burst stimulation for upper limb motor dysfunction in patients with stroke. ETHICS AND DISSEMINATION: This systematic review (SR) does not require formal ethical approval since no privacy health information will be included. The findings of this SR will be disseminated through peer-reviewed publications or conference presentations. PROSPERO REGISTRATION NUMBER: CRD42019142462.


Assuntos
Paralisia/reabilitação , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Magnética Transcraniana/métodos , Extremidade Superior/fisiopatologia , Força da Mão , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Reabilitação do Acidente Vascular Cerebral/efeitos adversos , Estimulação Magnética Transcraniana/efeitos adversos , Extremidade Superior/fisiologia
15.
ACS Omega ; 4(3): 4918-4926, 2019 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-31459676

RESUMO

Two sensitive and ratiometric fluorescent probes (probe I and probe II) were developed for the detection of fluoride ions. Probe I can detect fluoride ions quantitatively within a range of 0-6 µM and a detection limit of 73 nM, while probe II has a range of 0-40 µM and a detection limit of 138 nM. The test strips from probe I are quickly able to recognize F- (5 min) inside of the F- safety level in drinking water (1.0 mg/L, ∼5 µM) under 254 nm ultraviolet light, and the test strips from probe II quickly recognize F- (12 min) in dangerously high F- levels in water (4.0 mg/L, ∼21 µM) under 254 nm ultraviolet light. This combination of fluorescent paper sensors from probe I and probe II can be used as a simple and convenient tool to determine whether water is safe to drink or dangerous.

16.
Food Sci Biotechnol ; 28(4): 983-990, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31275698

RESUMO

A new fluorescent probe made from (E)-2-(benzo[d]thiazol-2-yl)-3-(6-hydroxynaphthalen-2-yl) acrylonitrile (Probe 1) was synthesized for the determination of bisulfite concentrations in real food samples (red wine and sugar). Adding bisulfite to a Probe 1 solution caused a marked decrease in fluorescence intensity and a visual color change from yellow to light yellow. This distinct color response indicates that Probe 1 could be used as a visual sensor for bisulfite. Probe 1 can detect bisulfite quantitatively in the range 0-400 µM with a detection limit of 0.10 µM. This makes Probe 1 a convenient signaling instrument for determining bisulfite levels in sugar and red wine samples.

17.
18.
Food Chem ; 286: 322-328, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827614

RESUMO

Benzenethiols are a class of flavoring ingredients used in the food, pharmaceutical, cosmetics and chemical industries. A rapid and visible colorimetric fluorescent probe was developed for the detection of benzenethiol flavors. It provides rapid quantitative detection of benzenethiols at low levels, down to a limit of 10 nM. Test paper containing the probe changes color according to benzenethiol concentration (from colorless to pink, visible with the naked eye). The probe was also successfully used to test benzenethiol concentrations in real food samples. This study demonstrates that this novel probe can be employed as a benzenethiol testing tool.


Assuntos
Colorimetria/métodos , Aromatizantes/análise , Corantes Fluorescentes/química , Fenóis/análise , Compostos de Sulfidrila/análise , Análise de Alimentos
19.
Medicine (Baltimore) ; 98(13): e15018, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30921224

RESUMO

RATIONALE: Old periprosthetic femoral fractures (OPFFs) around a tumor prosthesis of the knee present formidable problems for orthopedic oncologists; large bone defects and inappropriate biomechanics of the revision implant design can impair successful reconstruction. Limited literature is available on the reconstruction of OPFFs using revision combined with massive allograft following resection of a bone tumor around the knee joint. In this study, we present the first reported case in the English literature of a limited revision followed by several segmental allografts for the reconstruction of the knee joint. PATIENT CONCERNS: This case involved a 45-year-old female who was treated for a malignant fibrous histiocytoma (MFH) of the knee joint with surgical excision of the lesion and replacement of the defect using endoprosthetic reconstruction when she was 25 years old. Her surgical history was remarkable for a left tumoral knee prosthesis implanted 20 years ago. Nine years before revision, the patient had fall damage; however, she was able to walk independently and with moderate pain. In the 9-year period, prosthesis malfunction caused progressive left lower extremity shortening and a persistent swelling pain in the left thigh. DIAGNOSES: According to her clinical history, imaging results and physical examination, we confirmed the diagnosis of OPFFs potentially due to aseptic loosening and trauma injury. INTERVENTIONS: In this study, we present the first case of OPFFs around a tumor endoprosthesis that was successfully treated using limited revision combined with a massive allograft. OUTCOMES: At 80 months after revision surgery, the patient had made a sufficient recovery from her symptoms. The bone union was complete without tumor recurrence or implant failure. LESSONS: We propose that if prosthesis fracture is detected, revision surgery should be attempted as early as possible, and for patients with OPFFs, the use of limited revision combined with massive allografts may be useful for safely and adequately reconstructing OPFFs around the knee joint. However, patients should be followed-up closely after surgical treatment because of the high risk of revision.


Assuntos
Artroplastia do Joelho/efeitos adversos , Fraturas do Fêmur/cirurgia , Prótese do Joelho/efeitos adversos , Fraturas Periprotéticas/cirurgia , Complicações Pós-Operatórias/cirurgia , Aloenxertos , Neoplasias Ósseas/cirurgia , Feminino , Fraturas do Fêmur/etiologia , Histiocitoma Fibroso Maligno/cirurgia , Humanos , Articulação do Joelho/cirurgia , Pessoa de Meia-Idade , Fraturas Periprotéticas/etiologia , Complicações Pós-Operatórias/etiologia , Reoperação/métodos
20.
Int J Biol Macromol ; 131: 309-314, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30872058

RESUMO

The present paper aimed to obtain the polysaccharides with potent tyrosinase inhibitory activity from chestnut kernel. The ultrasound extracted polysaccharide fractions 1-1 (UEP1-1) and UEP2-1 were obtained by successive ultrasound-assisted-extraction, DEAE-52 and Sephadex G-100 chromatography. The Fourier transform infrared spectrum revealed that both UEP1-1 and UEP2-1 had the characteristic absorption peaks of polysaccharides. The degree of esterification of UEP1-1 (52.4%) and UEP2-1 (49.0%) was higher than that of the crude UEP (33.0%), indicating that the gel properties of the polysaccharides changed after purification. The x-ray diffraction patterns of UEP1-1 and UEP2-1 suggested that they were semi-crystalline polymers with a degree of crystallinity of 23.9 and 35.8%, respectively. The weight-average molecular weight (Mw) of UEP1-1 and UEP2-1 was 75.4 and 59.9 kDA, respectively. The monosaccharide composition of UEP1-1 and UEP2-1 was glucose, galactose, arabinose, mannose, xylose, rhamnose and fructose with different proportions. UEP1-1 displayed a dose-dependent inhibitory effect on tyrosinase activity, and the inhibition mode was found to be competitive.


Assuntos
Fagaceae/química , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Ativação Enzimática/efeitos dos fármacos , Peso Molecular , Monossacarídeos/química , Polissacarídeos/isolamento & purificação , Análise Espectral
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