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1.
RSC Adv ; 14(7): 4835-4843, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38318616

RESUMO

The sol-gel method is used to synthesize a new compound called Na3Fe0.8V1.2(PO4)3/C (NFVP/C), which has a crystal structure and belongs to the NASICON-type family. The dimensions of NFVP's unit cell are a = 8.717 (1) Å, c = 21.84 (1) Å, and V = 1437.27 (0) Å3. The Na‖NFVP/C battery provides a discharge potential of 3.43 V compared to Na+/Na, an intriguing rate capability of 76.2 mA h g-1 at 40C, and maintains an impressive capacity of 97.8% after 500 cycles at 5C. The excellent efficiency of Na3Fe0.8V1.2(PO4)3/C can be ascribed to its elevated Na+ conductivity and reduced energy barrier for sodium-ion diffusion. The NASICON-type Na3Fe0.8V1.2(PO4)3/C is a promising material for sodium-ion batteries.

2.
Contrast Media Mol Imaging ; 2022: 3556330, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35854781

RESUMO

In order to explore the clinical application value of intelligent health care knowledge combined with closed reduction intramedullary nail fixation in elderly patients with intertrochanteric fracture of the femur, a retrospective analysis is performed on 80 elderly patients who received intertrochanteric surgery from January 2019 to January 2021. All patients were divided into study group and control group based on intelligent medical knowledge received or not. During the phase of treatment, both the two groups were treated with closed reduction and intramedullary nailing. The control group received conventional knowledge training and rehabilitation before and after the surgery, and the research group received additional intelligent medical knowledge health care. Observations of patients after bed and ground time are compared and the VAS score is used to evaluate the pain degree at 12 h, 24 h, and 48 h after surgery. Besides, the incidence of postoperative complications in the two groups is observed. From the clinical follow-up results, it is clearly evident that intramedullary nail fixation based on medical care knowledge can effectively improve the hip function and quality of life in patients, reduce postoperative pain, and improve the prognosis of elderly patients with femoral trochanteric fracture.


Assuntos
Pinos Ortopédicos , Fraturas do Quadril , Idoso , Atenção à Saúde , Fraturas do Quadril/cirurgia , Humanos , Qualidade de Vida , Estudos Retrospectivos , Resultado do Tratamento
3.
J Healthc Eng ; 2021: 9971236, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34976333

RESUMO

It was to explore the effect of the CT and X-ray examinations before the hip replacement to predict the collapse of the necrotic femoral head under the classification of medical big data based on the decision tree algorithm of the difference grey wolf optimization (GWO) and provide a more effective examination basis for the treatment of patients with the osteonecrosis of the femoral head (ONFH). From January 2019 to January 2021, a total of 152,000 patients with ONFH and hip replacement in the tertiary hospitals were enrolled in this study. They were randomly divided into two groups, the study sample-X group (X-ray examination results) and based-CT group (CT examination results)-76,000 cases in each group. The actual measurement results of the femoral head form the gold standard to evaluate the effect of the two groups of detection methods. The measurement results of X-ray and CT before hip replacement are highly consistent with the detection results of the physical femoral head specimens, which can effectively predict the collapse of ONFH and carry out accurate staging. It is worthy of clinical promotion.


Assuntos
Necrose da Cabeça do Fêmur , Cabeça do Fêmur , Big Data , Cabeça do Fêmur/diagnóstico por imagem , Necrose da Cabeça do Fêmur/diagnóstico por imagem , Humanos , Tomografia Computadorizada por Raios X , Raios X
4.
Carbohydr Polym ; 242: 116396, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32564848

RESUMO

Quantum dots (QD)/polymer materials have wide applications in biological imaging, clinical diagnostics, anti-counterfeiting materials, light-emitting devices and solar cells. The development of QD/cellulose nanofibrils (CNF) hybrids with a more perfect structure and excellent properties is important for improving known applications. A unique tunicate CNF (TCNF) was homogeneously blended with outstanding CdSe/CdS core/shell QD to prepare a novel QD/TCNF hybrid. The QD were monodispersed on a single TCNF fibril surface as an evenly distributed monolayer with an extremely high packing density and no visible aggregation. The prepared hybrid is an excellent platform nanomaterial which was demonstrated by its good writing fidelity when applied as a 1D ink and by its good processability in the preparation of 2D films with acceptable transparency and flexibility. This one-step direct blending approach provides a facile shortcut to effectively fabricate cellulose-based high-performance functional QD nanomaterials at the single-fibril level.

5.
J Transl Med ; 18(1): 110, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32122362

RESUMO

BACKGROUND: Inflammatory damage following stroke aggravates brain damage, resulting in long-term neurological sequelae. The purpose of this study was to identify ways to reduce inflammatory reactions and to accelerate neuron regeneration after cerebral apoplexy. METHODS: We formulated a biomimetic vesicle, the leukosome, constituted by liposome, artificial long intergenic noncoding RNA (lincRNA)-EPS, and membrane proteins derived from macrophages and their physical-chemical characteristics were evaluated. Migration distance and cytotoxic levels were measured to determine the effect of lncEPS-leukosomes on lipopolysaccharide-activated microglia. An in vivo transient middle cerebral artery occlusion/reperfusion (tMCAO) model was established in mice, which were treated with lncEPS-leukosomes. Vesicle seepage, infiltration of inflammatory cells, cytotoxic levels in the cerebrospinal fluid, and neural stem cell (NSC) density were measured. RESULTS: Biomimetic vesicles with a homogeneous size increased lincRNA-EPS levels in activated microglia by 77.9%. In vitro studies showed that lincRNA-EPS inhibited the migration and cytotoxic levels of activated microglia by 63.2% and 43.6%, respectively, which promoted NSC proliferation and anti-apoptotic ability. In vivo data showed that leukosomes targeted to inflamed sites and lncEPS-leukosomes decreased the infiltration of inflammatory cells and cytotoxic levels by 81.3% and 48.7%, respectively. In addition, lncEPS-leukosomes improved neuron density in the ischemic core and boundary zone after tMCAO. CONCLUSIONS: The biomimetic vesicles formulated in this study targeted inflammatory cells and accelerated neuron regeneration by promoting inflammation resolution. This study may provide a promising treatment approach for accelerated neuron regeneration after cerebral apoplexy.


Assuntos
Isquemia Encefálica , RNA Longo não Codificante , Animais , Biomimética , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/complicações , Macrófagos , Camundongos , Microglia , Neurogênese , RNA Longo não Codificante/genética
6.
Arch Biochem Biophys ; 682: 108275, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-31962109

RESUMO

Stroke is one of the world's most deadly pathologies, and the rate of stroke recurrence is high. However, due to the complex nature of ischemia and reperfusion injury, there is presently no reliable treatment. The main factors driving brain damage from ischemic stroke are neuronal cell death resulting from oxidative stress, inflammation, and failure of the blood brain barrier. While under normal conditions, the blood brain barrier acts as a selectively permeable membrane allowing solutes and other substances to pass into the tissues of the central nervous system, ischemia and reperfusion alter the expression of tight junction proteins such as occludin, which leads to unmitigated perfusion and loss of homeostasis. Phoenixin-14 is a 14-amino acid neuropeptide that has been shown to play a role in regulating reproduction, blood sugar metabolism, pain, anxiety, and more recently, certain aspects of ischemic cardiac injury. In the present study, we found that phoenixin-14 confers protective effects against oxygen-glucose deprivation/reoxygenation (OGD/R) injury in bEnd.3 brain endothelial cells. Phoenixin-14 attenuated oxidative stress via downregulation of ROS and NOX1 and inhibited HMGB1 expression. Additionally, phoenixin-14 increased the expression of eNOS and NO, which play a protective role. Phoenixin-14 reduced endothelial monolayer permeability by increasing the expression of occludin. Finally, we found that the effects of phoenixin-14 on the expression of eNOS and occludin are dependent on the KLF2 transcriptional pathway, as evidenced by the results of our KLF2 knockdown experiment. Thus, phoenixin-14 may serve as a novel therapeutic agent for ischemic stroke.


Assuntos
Encéfalo/irrigação sanguínea , Células Endoteliais/metabolismo , Glucose/metabolismo , Inflamação/metabolismo , Neuropeptídeos/farmacologia , Oxigênio/metabolismo , Acidente Vascular Cerebral/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Linhagem Celular , Células Endoteliais/efeitos dos fármacos , Homeostase , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Óxido Nítrico Sintase Tipo III/metabolismo , Estresse Oxidativo , Peptídeos , Permeabilidade , Substâncias Protetoras/farmacologia , Traumatismo por Reperfusão/metabolismo
7.
ACS Appl Mater Interfaces ; 9(15): 13508-13519, 2017 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-28350431

RESUMO

This work reveals the structural variations of cellulose nanofibers (CNF) prepared from different cellulose sources, including softwood (Picea abies), hardwood (Eucalyptus grandis × E. urophylla), and tunicate (Ciona intestinalis), using different preparation processes and their correlations to the formation and performance of the films prepared from the CNF. Here, the CNF are prepared from wood chemical pulps and tunicate isolated cellulose by an identical homogenization treatment subsequent to either an enzymatic hydrolysis or a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation. They show a large structural diversity in terms of chemical, morphological, and crystalline structure. Among others, the tunicate CNF consist of purer cellulose and have a degree of polymerization higher than that of wood CNF. Introduction of surface charges via the TEMPO-mediated oxidation is found to have significant impacts on the structure, morphology, optical, mechanical, thermal, and hydrophobic properties of the prepared films. For example, the film density is closely related to the charge density of the used CNF, and the tensile stress of the films is correlated to the crystallinity index of the CNF. In turn, the CNF structure is determined by the cellulose sources and the preparation processes. This study provides useful information and knowledge for understanding the importance of the raw material for the quality of CNF for various types of applications.

8.
Environ Sci Pollut Res Int ; 24(8): 7264-7273, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28101711

RESUMO

In this study, reduced graphene oxide (rGO) embedded with bimetallic nanoparticles of cobalt-manganese oxide (CoMn2O4) was fabricated by hydrothermal treatment. The obtained product was characterized and applied for the heterogeneous activation of peroxymonosulfate (PMS) to degrade acid orange 7 (AO7). The characterization results revealed that 10-20 nm nanosized CoMn2O4 was homogenously decorated on the surface of rGO. The effect of different CoMn2O4 loadings showed that catalyst with a CoMn2O4 contents higher than 20% performs stronger capability for catalytic degradation of AO7 compared to pure CoMn2O4. In a system containing 4 mM PMS and 0.05 g/L 50% CoMn2O4/rGO, 100% conversion of AO7 (70 mg/L) and 43% mineralization could be achieved within 12 and 60 min, respectively. Recycling experiment along with XRD data demonstrates good stability of the catalyst for five successive runs. Inhibition confirmation results suggest that surface-bound SO4•- and HO• radicals both played a key role in degradation of AO7. Therefore, this material demonstrates a very efficient catalytic performance for the degradation of organic dyes.


Assuntos
Compostos Azo , Benzenossulfonatos , Cobalto/química , Grafite/química , Compostos de Manganês/química , Óxidos/química , Poluentes Químicos da Água , Purificação da Água/métodos , Compostos Azo/análise , Compostos Azo/química , Compostos Azo/isolamento & purificação , Benzenossulfonatos/análise , Benzenossulfonatos/química , Benzenossulfonatos/isolamento & purificação , Nanopartículas/química , Oxirredução , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
9.
Z Naturforsch C J Biosci ; 71(5-6): 165-80, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27049617

RESUMO

To explore abundant marine ascidian bioresources, four species from two orders have been compared in their chemical compositions. After a universal separation of the animal body into two fractions, all tunics have been found rich in carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid (DAA) content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. There are species-specific characteristics observed for vanadium accumulation and sterol structures which are also meaningful for ascidian chemotaxonomy and resource exploitation. It is suggested that in addition to the present utilizations of tunics for cellulose production and of some species' inner body tissues as human food, one should explore all species' inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts for, e.g. pharmaceutical and chemical industries.


Assuntos
Urocordados/química , Urocordados/metabolismo , Animais , Humanos , Especificidade da Espécie
10.
Environ Sci Pollut Res Int ; 23(6): 5352-60, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26564189

RESUMO

The content and speciation of heavy metals can fundamentally affect the hydrolysis of sludge. This research study investigates the migration and transformation rule of heavy metals during the hydrolysis process by measuring the content of exchangeables (F1), bound to carbonates (F2), bound to Fe-Mn oxides (F3), bound to organic matter (F4), and residuals (F5) under different periods of time undergoing hydrolysis. The results show that the hydrolysis process generally stabilized Cu, Zn, Mn, Ni, Pb, Cr, and As by transforming the unstable states into structurally stable states. Such transformations and stabilization were primarily caused by the changes in local metal ion environment and bonding structure, oxidation of sulfides, pyrolyzation of organic matter, and evaporation of resulting volatile materials. An X-ray diffractometry (XRD) of the residuals conducted after hydrolysis indicated that hydrolysis did have a significant influence on the transportation and transformation of heavy metals.


Assuntos
Metais Pesados/química , Proteínas/isolamento & purificação , Esgotos/química , Carbonatos/química , Hidrólise , Óxidos/química , Sulfetos/química
11.
Materials (Basel) ; 9(3)2016 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-28773252

RESUMO

The industrial lignin used here is a byproduct from Kraft pulp mills, extracted from black liquor. Since lignin is inexpensive, abundant and renewable, its utilization has attracted more and more attention. In this work, lignin was used for the first time as binder material for LiFePO4 positive and graphite negative electrodes in Li-ion batteries. A procedure for pretreatment of lignin, where low-molecular fractions were removed by leaching, was necessary to obtain good battery performance. The lignin was analyzed for molecular mass distribution and thermal behavior prior to and after the pretreatment. Electrodes containing active material, conductive particles and lignin were cast on metal foils, acting as current collectors and characterized using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge cycles. Good reversible capacities were obtained, 148 mAh·g-1 for the positive electrode and 305 mAh·g-1 for the negative electrode. Fairly good rate capabilities were found for both the positive electrode with 117 mAh·g-1 and the negative electrode with 160 mAh·g-1 at 1C. Low ohmic resistance also indicated good binder functionality. The results show that lignin is a promising candidate as binder material for electrodes in eco-friendly Li-ion batteries.

12.
Cell Prolif ; 48(5): 582-92, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26250586

RESUMO

OBJECTIVES: MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression and mediate diverse physiological processes. In this study, we investigated functions of miRNA miR-34c-3p in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: miR-34c-3p expression was evaluated by qPCR. Cell viability was examined by MTT and proliferation by cell cycle analysis. Cell migration and invasion were tested using Transwells with/without Matrigel coating. Western blot analysis was performed for eIF4E, c-Myc, Cyclin D1, survivin and Mcl-1 protein expression. RESULTS: miR-34c-3p expression was significantly reduced in tissues and serum samples from NSCLC patients and in NSCLC cell lines A549, H460, H23, H157 and H1299. Overexpression of miR-34c-3p in A549 and H157 cells reduced cell proliferation, migration and invasion, whereas transfection with miR-34c-3p inhibitor (miR-34c-3p-in) produced opposite effects. Target analysis using algorithms miRanda, TargetScan and DIANA identified eIF4E as a potential target of miR-34c-3p. Luciferase assay using the eIF4E 3'-UTR reporter carrying a putative miR-34c-3p target sequence revealed eIF4E to be a specific target of miR-34c-3p. Overexpression of miR-34c-3p in NSCLS cell lines led to significant reduction in mRNA and protein levels of eIF4E, whereas inhibition of miR-34c-3p resulted in significant increase in eIf4e protein levels, confirming eIF4E to be a direct target of miR-34c-3p in NSCLS. Overexpression of eIF4E in A549 cells promoted cell proliferation, migration and invasion, which were partially reversed by miR-34c-3p. CONCLUSION: miR-34c-3p directly targeted eIF4E and reduced miR-34c-3p expression in NSCLC, promoting cell cycle progression, proliferation, migration and invasion.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/patologia , Regulação para Baixo/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Neoplasias Pulmonares/patologia , MicroRNAs/metabolismo , Regiões 3' não Traduzidas , Sequência de Bases , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Fator de Iniciação 4E em Eucariotos/antagonistas & inibidores , Fator de Iniciação 4E em Eucariotos/genética , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/metabolismo , Alinhamento de Sequência
13.
Lipids ; 50(10): 1009-27, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26233815

RESUMO

In order to establish Ciona intestinalis as a new bioresource for n-3 fatty acids-rich marine lipids, the animal was fractionated into tunic and inner body tissues prior to lipid extraction. The lipids obtained were further classified into neutral lipids (NL), glycolipids (GL) and phospholipids (PL) followed by qualitative and quantitative analysis using GC-FID, GC-MS, (1)H NMR, 2D NMR, MALDI-TOF-MS and LC-ESI-MS methods. It was found that the tunic and inner body tissues contained 3.42-4.08% and 15.9-23.4% of lipids respectively. PL was the dominant lipid class (42-60%) irrespective of the anatomic fractions. From all lipid fractions and classes, the major fatty acids were 16:0, 18:1n-9, C20:1n-9, C20:5n-3 (EPA) and C22:6n-3 (DHA). The highest amounts of long chain n-3 fatty acids, mainly EPA and DHA, were located in PL from both body fractions. Cholestanol and cholesterol were the dominant sterols together with noticeable amounts of stellasterol, 22 (Z)-dehydrocholesterol and lathosterol. Several other identified and two yet unidentified sterols were observed for the first time from C. intestinalis. Different molecular species of phosphatidylcholine (34 species), sphingomyelin (2 species), phosphatidylethanolamine (2 species), phosphatidylserine (10 species), phosphatidylglycerol (9 species), ceramide (38 species) and lysophospholipid (5 species) were identified, representing the most systematic PL profiling knowledge so far for the animal. It could be concluded that C. intestinalis lipids should be a good alternative for fish oil with high contents of n-3 fatty acids. The lipids would be more bioavailable due to the presence of the fatty acids being mainly in the form of PL.


Assuntos
Ciona intestinalis/química , Ácidos Graxos Ômega-3/análise , Fosfolipídeos/análise , Animais , Ciona intestinalis/anatomia & histologia , Glicolipídeos/análise , Espectroscopia de Prótons por Ressonância Magnética/métodos
14.
Mol Med Rep ; 12(3): 3734-3738, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26045182

RESUMO

Allicin, a molecule predominantly responsible for the pungent odor and the antibiotic function of garlic, exhibits various pharmacological activities and has been suggested to be beneficial in the treatment of various disorders. The present study aimed to elucidate the effect of allicin in cerebral ischemia/reperfusion (I/R) injury in rats. Rats were subjected to 1.5 h of transient middle cerebral artery occlusion (MCAO), followed by 24 h of reperfusion. Rats were randomly assigned to the sham surgery group, the MCAO group and the MCAO + allicin group. Neurological score, cerebral infarct size, brain water content, neuronal apoptosis, serum tumor necrosis factor (TNF)­α and myeloperoxidase (MPO) activity were measured. The results suggested that allicin reduced cerebral infarction area, brain water content, neuronal apoptosis, TNF­α levels and MPO activity in the serum. The results of the present study indicated that allicin protects the brain from cerebral I/R injury, which may be ascribed to its anti­apoptotic and anti­inflammatory effects.


Assuntos
Anti-Infecciosos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Encéfalo/efeitos dos fármacos , Infarto da Artéria Cerebral Média/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Ácidos Sulfínicos/uso terapêutico , Animais , Anti-Infecciosos/química , Anti-Inflamatórios/química , Apoptose/efeitos dos fármacos , Encéfalo/patologia , Edema Encefálico/sangue , Edema Encefálico/tratamento farmacológico , Edema Encefálico/patologia , Modelos Animais de Doenças , Dissulfetos , Alho/química , Infarto da Artéria Cerebral Média/sangue , Infarto da Artéria Cerebral Média/patologia , Masculino , Fármacos Neuroprotetores/química , Peroxidase/sangue , Ratos Sprague-Dawley , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/patologia , Ácidos Sulfínicos/química , Fator de Necrose Tumoral alfa/sangue
15.
J Environ Sci (China) ; 28: 14-21, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25662233

RESUMO

The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral resources. The effective use of these secondary resources is becoming an important and urgent problem for all environmental protection staff. Manganese-catalyzed ozonation for the pre-oxidation of cyanided tailings was studied and the effects of Mn2+ dosage, initial sulfuric acid concentration, ozone volume flow, temperature and agitation speed on pretreatment were examined. The optimum reaction conditions were observed to be: ore pulp density 2.5%, agitation speed 700 r/min, temperature 60°C, Mn2+ dosage 40 g/L, ozone volume flow 80 L/hr, initial sulfuric acid concentration 1 mol/L, and reaction time 6 hr. Under these conditions, the leaching rate of Fe and weight loss could reach 94.85% and 48.89% respectively. The leaching process of cyanided tailings by Mn2+/O3 was analyzed, and it was found that the leaching of pyrite depends on synergetic oxidation by high-valent manganese and O3, in which the former played an important part.


Assuntos
Poluentes Ambientais/química , Poluição Ambiental/prevenção & controle , Recuperação e Remediação Ambiental/métodos , Resíduos Industriais/prevenção & controle , Manganês/química , Ozônio/química , Catálise , Cianetos/química , Ouro/química , Ferro/química , Mineração , Oxirredução , Reciclagem , Ácidos Sulfúricos/química
16.
Carbohydr Res ; 402: 172-9, 2015 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-25498017

RESUMO

The main hemicellulose in softwood, glucomannan (GM), structurally resembles cellulose but has quite different physical and chemical properties. In addition to branching and original acetylation, the only other difference between these two ß-1,4-linked glycans is the configuration at C-2 in approximately 80% of the sugar residues. In contrast to glucose, the 2-OH in mannose has an axial orientation. The influence of this stereochemistry on the relative reactivities of glucosyl compared to mannosyl units in methylation reactions are studied in this work. Glucomannan isolated from spruce (SGM) and commercially available konjac glucomannan (KGM) was methylated in DMSO/Li-dimsyl/MeI and water/NaOH/MeI system, respectively. In the early stage of the reaction, the glucose part of the SGM achieved slightly higher DS values than the mannose residues, but the overall relative rate constants were close to 1:1. The order of reactivities in glucose was k2>k3>k6 and k3>k2>k6 for mannose (in DMSO/Li-dimsyl/MeI). The rate constants did not remain constant, but k3 decreased when k2 increased for both epimeric sugars. In water/NaOH/MeI, the methylation of the primary 6-OH was much more pronounced with an order of reactivity of O-6>O-2>O-3 for mannose and O-2>O-6>O-3 for glucose. The results are discussed with respect to the OH-acidity and the stereoelectronic, sterical, and solvent effects.


Assuntos
Mananas/química , Oxigênio/química , Solventes/química , Manose/química , Metilação , Estereoisomerismo
17.
Carbohydr Polym ; 117: 286-296, 2015 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-25498637

RESUMO

Cellulose nanocrystals (CNs) were prepared from tunicate by enzymatic hydrolysis (ECN), TEMPO-mediated oxidation (TCN) and acid hydrolysis (ACN). They were cast alone or blended with glucomannan (GM) from konjac or spruce to prepare films. Different CNs were obtained with a yield of ECN>TCN>ACN with corresponding order of decreased Mw but increased crystallinity. The CNs' diameters were on the nanometre scale, with lengths of ECN>TCN>ACN. For CN-films, TCN and ACN fibrils were stretched and parallel to each other due to surface charges. For CN-GM films, both components interacted strongly with each other, resulting in changes of crystallinity, specific surface area, fibril diameter and contact angle compared with CN films. The composite films had good thermal, optical and mechanical properties; the last ones are apparently better than similar films reported in the literature. This is the first systematic study of different tunicate CN-GM nanocomposite films and the first ever for spruce GM.


Assuntos
Celulose/química , Mananas/química , Nanocompostos/química , Nanopartículas/química , Animais , Celulose/análogos & derivados , Ciona intestinalis/química
18.
Asian Pac J Cancer Prev ; 15(6): 2613-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24761872

RESUMO

AIMS: Dysfunction of the host immune system in cancer patients can be due to a number of factors, including lymphocyte apoptosis. Several studies showed that Foxp3+T cells take part in inducing this process by expressing FasL in tumor patients. However, the relationship between apoptosis, CD8+T cells and Foxp3+T cells in HCC patients is still unclear. The present study was designed to investigate the correlation between apoptosis levels and Fas/FasL expression in CD8+T lymphocytes and Foxp3+T cells in patients with HCC. METHODS: CD8+T cells and CD3+Foxp3+T cells were tested from peripheral blood of HCC patients and normal controls and subjected to multicolor flow cytometry. The expression of an apoptosis marker (annexin V) and the death receptor Fas in CD8+T cells and FasL in CD3+Foxp3+T cells were evaluated. Serum TGF-ß1 levels in patients with HCC were measured by enzyme-linked immunosorbent assay. The relationship between apoptosis and Fas expression, as well as FasL expression in CD3+Foxp3+T cells was then evaluated. RESULTS: The frequency of CD8+T cells binding annexin V and Fas expression in CD8+T cells, were all higher in HCC patients than normal controls and the proportion of apoptotic CD8+T cells correlated with their Fas expression. Serum TGF-ß1 levels correlated inversely with CD3+Foxp3+T cells. CONCLUSIONS: Fas/FasL interactions might lead to excessive turnover of CD8+T cells and reduce anti-tumor immune responses in patients with HCC. Further investigations of apoptosis induction in Fas+CD8+T cells in vitro are required.


Assuntos
Apoptose , Complexo CD3/metabolismo , Linfócitos T CD8-Positivos/patologia , Carcinoma Hepatocelular/patologia , Proteína Ligante Fas/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Linfócitos T Reguladores/patologia , Receptor fas/metabolismo , Complexo CD3/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/metabolismo , Estudos de Casos e Controles , Proteína Ligante Fas/imunologia , Feminino , Citometria de Fluxo , Seguimentos , Fatores de Transcrição Forkhead/imunologia , Humanos , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Transdução de Sinais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Receptor fas/imunologia
19.
Carbohydr Polym ; 106: 60-70, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24721051

RESUMO

The thermal degradation behavior and kinetics of spruce glucomannan (SGM) and its methylated derivatives were investigated using thermogravimetric analysis to characterize its temperature-dependent changes for use in specific applications. The results were compared with those obtained for commercial konjac glucomannan (KGM). The SGM and the KGM exhibited two overlapping peaks from 200 to 375°C, which correspond to the intensive devolatilization of more than 59% of the total weight. Differences in the pyrolysis-product distributions and thermal stabilities appeared as a result of the different chemical compositions and molecular weights of the two GMs. The Friedman and Flynn-Wall-Ozawa isoconversional methods and the Coats-Redfern were adopted to determine the kinetic triplet of the intensive devolatilization region. Both GMs can be modeled using a complex mechanism that involves both a Dn-type and an Fn-type reaction. The comparative study of partially methylated GM indicated higher homogeneity and thermal resistance for the material with the higher degree of substitution.


Assuntos
Catárticos/química , Mananas/química , Picea/química , Temperatura Alta , Cinética , Metilação , Termogravimetria
20.
Planta ; 239(5): 1079-90, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24531838

RESUMO

Xylan-lignin (XL), glucomannan-lignin (GML) and glucan-lignin (GL) complexes were isolated from spruce wood, hydrolyzed with xylanase or endoglucanase/ß-glucosidase, and analyzed by analytical pyrolysis and 2D-NMR. The enzymatic hydrolysis removed most of the polysaccharide moieties in the complexes, and the lignin content and relative abundance of lignin-carbohydrate linkages increased. Analytical pyrolysis confirmed the action of the enzymatic hydrolysis, with strong decreases of levoglucosane and other carbohydrate-derived products. Unexpectedly it also revealed that the hydrolase treatment alters the pattern of lignin breakdown products, resulting in higher amounts of coniferyl alcohol. From the anomeric carbohydrate signals in the 2D-NMR spectra, phenyl glycoside linkages (undetectable in the original complexes) could be identified in the hydrolyzed GML complex. Lower amounts of glucuronosyl and benzyl ether linkages were also observed after the hydrolysis. From the 2D-NMR spectra of the hydrolyzed complexes, it was concluded that the lignin in GML is less condensed than in XL due to its higher content in ß-O-4' ether substructures (62 % of side chains in GML vs 53 % in XL) accompanied by more coniferyl alcohol end units (16 vs 13 %). In contrast, the XL lignin has more pinoresinols (11 vs 6 %) and dibenzodioxocins (9 vs 2 %) than the GML (and both have ~13 % phenylcoumarans and 1 % spirodienones). Direct 2D-NMR analysis of the hydrolyzed GL complex was not possible due to its low solubility. However, after sample acetylation, an even less condensed lignin than in the GML complex was found (with up to 72 % ß-O-4' substructures and only 1 % pinoresinols). The study provides evidence for the existence of structurally different lignins associated to hemicelluloses (xylan and glucomannan) and cellulose in spruce wood and, at the same time, offers information on some of the chemical linkages between the above polymers.


Assuntos
Glucanos/química , Hidrolases/metabolismo , Lignina/química , Mananas/química , Picea/química , Madeira/química , Xilanos/química , Configuração de Carboidratos , Celulase/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Hidrólise , Lignina/metabolismo , Espectroscopia de Ressonância Magnética , Mananas/metabolismo , Madeira/metabolismo , Xilanos/metabolismo
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