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1.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 38(2): 351-360, 2021 Apr 25.
Artigo em Zh | MEDLINE | ID: mdl-33913296

RESUMO

The real physical image of the affected limb, which is difficult to move in the traditional mirror training, can be realized easily by the rehabilitation robots. During this training, the affected limb is often in a passive state. However, with the gradual recovery of the movement ability, active mirror training becomes a better choice. Consequently, this paper took the self-developed shoulder joint rehabilitation robot with an adjustable structure as an experimental platform, and proposed a mirror training system completed by next four parts. First, the motion trajectory of the healthy limb was obtained by the Inertial Measurement Units (IMU). Then the variable universe fuzzy adaptive proportion differentiation (PD) control was adopted for inner loop, meanwhile, the muscle strength of the affected limb was estimated by the surface electromyography (sEMG). The compensation force for an assisted limb of outer loop was calculated. According to the experimental results, the control system can provide real-time assistance compensation according to the recovery of the affected limb, fully exert the training initiative of the affected limb, and make the affected limb achieve better rehabilitation training effect.


Assuntos
Robótica , Articulação do Ombro , Reabilitação do Acidente Vascular Cerebral , Eletromiografia , Humanos , Movimento , Força Muscular
2.
Org Biomol Chem ; 17(35): 8071-8074, 2019 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-31464338

RESUMO

A transition metal-free and external oxidant-free annulation of substrates having two nitrogen-nucleophilic sites with ClCF2COONa was demonstrated, affording a series of 1,3,5-triazines and quinazolinones in up to 96% yields. Notably, ClCF2COONa was employed as the C1 synthon for valuable heterocycles. Using this protocol, two C-N bonds were formed in one pot via the cleavage of two C-F bonds, one C-Cl bond and one C-C bond. This method avoided the use of a transition metal and an oxidant and generated low toxicity inorganic waste.

3.
Org Biomol Chem ; 16(15): 2629-2633, 2018 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-29610816

RESUMO

An iodine-mediated formal oxidative cycloaddition of amidines with tertiary amines was first demonstrated in air. Both symmetrical and unsymmetrical 2,4-disubstituted 1,3,5-triazines were obtained in up to 85% yields. It is noted that a tertiary amine was employed as a one carbon synthon of 1,3,5-triazines and two C-N bonds were formed in one pot. Control experiments revealed that the reaction underwent a radical pathway promoted by I+. The method is transition-metal-free, peroxide-free, and operationally simple to implement with a wide scope of substrates.

4.
J Org Chem ; 82(16): 8628-8633, 2017 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-28741945

RESUMO

A copper-catalyzed oxidative formal [2+2+1+1] cycloaddition for the synthesis of symmetrical tetrasubstituted pyridines was first demonstrated. The reaction is involved in a domino cross-dehydrogenative coupling (CDC) of ß-keto esters and N-methylamides, the C-N bond cleavage, the Michael addition, and a condensation and oxidative aromatization process. Multiple C-C and C-N bonds were constructed in one pot via the C-H and C-N cleavage of N-methylamides, which were employed as the carbon source of pyridines. The preliminary mechanistic studies revealed that the C(sp3)-H bond cleavage of N-methylamides was the rate-determining step.

5.
J Org Chem ; 80(11): 5581-7, 2015 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-25942678

RESUMO

An iodine-catalyzed oxidative C(sp(3))-H amination/C-N cleavage of tertiary amines couducted under an oxygen atmosphere has been developed and affords a route to quinazolines and quinazolinones in good to excellent yields via a domino ring annulation. The method is metal-free, peroxide-free, and operationally simple to implement with a wide scope of substrates and represents a new avenue for multiple C-N bond formations.

6.
J Org Chem ; 80(9): 4736-42, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25849218

RESUMO

A copper-catalyzed radical methylation/sp(3) C-H amination/oxidation reaction for the facile synthesis of quinazolinone was developed. In this cascade reaction, dicumyl peroxide acts not only as a useful oxidant but also as an efficient methyl source. Notably, a methyl radical, generated from peroxide, was confirmed by electron paramagnetic resonance for the first time.

7.
Org Biomol Chem ; 12(27): 4837-40, 2014 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-24903102

RESUMO

A general and practical route to the synthesis of multisubstituted pyrrolo[1,2-a]quinolines has been described from 2-alkylazaarenes and nitroolefins using cerium chloride as a catalyst via a tandem Michael addition, cyclization and aromatization. This protocol features readily available starting materials, operational simplicity and high regioselectivity to access multifunctionalized pyrrolo[1,2-a]quinolines with the formation of multiple C-C and C-N bonds in one pot. In addition, various substitution patterns and functional groups were found to be compatible under the optimized conditions, which was lacking in the existing procedures.

8.
Int J Biol Macromol ; 257(Pt 1): 128647, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056152

RESUMO

The aim of this study was to investigate the effect of plasma-activated water (PAW) during extrusion on the formation of endogenous starch complexes with wheat starch (WS) as a model material. Using PAW during the extrusion process resulted in an increase in amylose content from 27.87 % to 30.07 %. Results from Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry indicated that the PAW facilitated the formation of endogenous starch-lipid complexes during extrusion. PAW120 (distilled water treated by plasma for 120 s) showed a better promotion effect than PAW60 (distilled water treated by plasma for 60 s). EWS120 (WS extruded using PAW120) exhibited lower peak viscosity and swelling power, but higher solubility, particle size, and resistant starch content compared with EWS0 (WS extruded using distilled water) and EWS60 (WS extruded using PAW60). In a word, the acidic substances in PAW may lead to hydrolysis of starch and generate more amylose, thus improving the amount of endogenous starch-lipid complexes. The present study provides a novel extrusion method to obtain modified starch with higher RS content than common extrusion, which has potential application in the industrial production of functional foods with low glycemic index.


Assuntos
Amilose , Amido , Amido/química , Amilose/química , Triticum/química , Água/química , Difração de Raios X , Lipídeos
9.
Int J Biol Macromol ; 254(Pt 3): 128054, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37956800

RESUMO

In this study, the synergistic effect of plasma-activated water (PAW) combined with twin-screw extrusion (TSE) on multi-scale structure, physicochemical and digestive properties of yam starch (YS) was studied. PAW-TSE resulted in higher amylose content in YS than TSE alone. Compared with single TSE, the relative crystallinity, short-range ordered degree, and gelatinization enthalpy of YS were increased by PAW-TSE according to the results of X-ray diffraction, Fourier transform infrared, Raman spectroscopy, and differential scanning calorimetry. Furthermore, rapid viscosity and dynamic rheological analysis showed that the peak and breakdown viscosity of PAW-TSE treated YS paste were considerably reduced, and the storage modulus and loss modulus were significantly increased, indicating that the gel strength and thermal stability were improved. In addition, the resistant starch (RS) content of YS treated by PAW-TSE increased from 6.04 % to 21.21 %. Notably, the effect of PAW-TSE on YS enhanced with the preparation time of PAW increased. Finally, correlation analysis indicated that the characteristic indexes of PAW had a significant impact on the long or short-range ordered structure, thermal properties, and in vitro digestibility of YS during extrusion. Therefore, PAW-TSE, as an emerging dual modification technology, will greatly expand the application of extrusion technology.


Assuntos
Dioscorea , Amido , Amido/química , Dioscorea/metabolismo , Água/química , Amilose/química , Difração de Raios X , Viscosidade
10.
Foods ; 13(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38338597

RESUMO

In this study, the effect of konjac glucomannan (KGM, 0-5%) on the structure, physicochemical properties, and in vitro digestibility of extruded yam starch (EYS) was investigated. The EYS became rougher on the surface and the particle size increased as observed using scanning electron microscopy and particle size analysis. X-ray diffraction and Raman results revealed that the relative crystallinity (18.30% to 22.30%) of EYS increased, and the full width at half maxima at 480 cm-1 decreased with increasing KGM content, indicating the increment of long-range and short-range ordered structure. Differential scanning calorimetry and rheological results demonstrated that KGM enhanced thermal stability and the gel strength of EYS due to enhanced interaction between KGM and YS molecules. Additionally, a decrease in the swelling power and viscosity of EYS was observed with increased KGM content. The inclusion of KGM in the EYS increased the resistant starch content from 11.89% to 43.51%. This study provides a dual-modified method using extrusion and KGM for modified YS with high thermal stability, gel strength, and resistance to digestion.

11.
Int J Biol Macromol ; 264(Pt 1): 130461, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428767

RESUMO

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch.


Assuntos
Dioscorea , Amido , Amido/química , Dioscorea/química , Solubilidade , Hidrólise , Viscosidade
12.
Org Biomol Chem ; 11(26): 4304-7, 2013 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-23736745

RESUMO

A facile CuI-catalyzed and air promoted oxidative cyclization was developed for the synthesis of polyarylated oxazoles. By virtue of this method, a variety of arylated oxazoles could be easily synthesized from readily available starting materials at room temperature in air.


Assuntos
Cobre/química , Oxazóis/síntese química , Catálise , Ciclização , Hidrocarbonetos Aromáticos/síntese química , Oxirredução
13.
Org Biomol Chem ; 11(39): 6691-4, 2013 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-23995231

RESUMO

A cobalt-catalyzed oxidative [3 + 2] cycloaddition cascades of dihydroisoquinoline esters with nitroolefins or N-sulfuryl aldimines were developed at room temperature. A multi-component reaction for the synthesis of 5,6-dihydroimidazo[2,1-a]isoquinolines were also realized under almost identical conditions. This method is particularly suitable for the synthesis of tricyclic nitrogen heterocycles due to its simple manipulation, wide scope of the reaction substrates and excellent regioselectivity.

14.
Int J Biol Macromol ; 242(Pt 3): 125056, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37245772

RESUMO

In this study, the debranching followed by malate esterification was employed to prepare malate debranched waxy maize starch (MA-DBS) with a high degree of substitution (DS) and low digestibility using malate waxy maize starch (MA-WMS) as the control. The optimal esterification conditions were obtained using an orthogonal experiment. Under this condition, the DS of MA-DBS (0.866) was much higher than that of MA-WMS (0.523). A new absorption peak was generated at 1757 cm-1 in the infrared spectra, indicating the occurrence of malate esterification. Compared with MA-WMS, MA-DBS had more particle aggregation, resulting in an increase in the average particle size from scanning electron microscopy and particle size analysis. The X-ray diffraction results showed that the relative crystallinity decreased after malate esterification, in which the crystalline structure of MA-DBS almost disappeared, which was consistent with the decrease of decomposition temperature by thermogravimetric analysis and the disappearance of the endothermic peak by differential scanning calorimeter. In vitro digestibility tests showed an order: WMS > DBS > MA-WMS > MA-DBS. The MA-DBS showed the highest content of resistant starch (RS) of 95.77 % and the lowest estimated glycemic index of 42.27. In a word, pullulanase debranching could produce more short amylose, promoting malate esterification and improving the DS. The presence of more malate groups inhibited the formation of starch crystals, increased particle aggregation, and enhanced resistance to enzymolysis. The present study provides a novel protocol for producing modified starch with higher RS content, which has potential application in functional foods with a low glycemic index.


Assuntos
Malatos , Zea mays , Esterificação , Zea mays/química , Amido/química , Amilopectina , Amido Resistente
15.
Foods ; 12(2)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36673452

RESUMO

Extrusion is a method of processing that changes the physicochemical and rheological properties of starch and protein under specific temperature and pressure conditions. In this study, twin-screw extrusion technology was employed to prepare yam starch-soy protein isolate complexes. The structure and properties of the complexes and their effects on the quality of dough were studied. The results showed changes in the X-ray diffraction, rheology, and in vitro digestibility of the complexes. The extruded starch-protein complex formed an A+V-type crystal structure with the addition of soy protein isolate. A small amount of soy protein isolate could improve the complex's viscoelasticity. As the content of soy protein isolate increased, the content of slow-digesting starch and resistant starch in the complexes increased, and the digestibility decreased. The microstructure of the dough indicated that the network structure of the puffed yam starch-protein complex dough was more uniform than that of the same amount of puffed yam starch. The moisture distribution of the dough showed that with the addition of extruded flour, the closely bound water content of the dough increased, and the weakly bound water content decreased. The hardness, gumminess, chewiness, and resilience of the dough decreased. In conclusion, extruded starch-protein complexes can improve dough quality and provide technical support for the broad application of yam.

16.
Front Nutr ; 9: 842662, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35198591

RESUMO

In this research, annealing (ANN) using plasma-activated water (PAW) was first employed to modify potato and pea starches. Compared with the conventional ANN using distilled water (DW), the granular morphology of two starches was not significantly affected by PAW-ANN. The results of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy showed that PAW-ANN could reduce the long and short-range ordered structure of potato starch while improving the long and short-range ordered structure of pea starch. Differential scanning calorimetry (DSC) analysis indicated that PAW-ANN lowered the gelatinization enthalpy of potato starch and increased the gelatinization enthalpy of pea starch. The analysis of viscosity and dynamic rheological characteristics illustrated that PAW-ANN reduced the peak viscosity and improved the gel strength of starch pastes. PAW-ANN represents a novel modification method for modifying the structure, reducing the viscosity, improving the gel strength of starch, and is very promising for applying in starch-based hydrogels and food additives.

17.
Front Nutr ; 9: 850227, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35369070

RESUMO

The study investigated the effects of plasma-activated water (PAW) and heat moisture treatment (HMT) on the rheological properties of wheat flour and the in vitro digestibility of steamed bread partially replaced by the modified wheat flour. After HMT, the gelatinization temperature of wheat flour increased and the gelatinization enthalpy reduced. The solubility and swelling power of wheat flour increased after the heat-moisture treatment. The solubility of modified flour after PAW-HMT treatment was lower than that of distilled water (DW)-HMT at the same temperature. The wheat flour with HMT had higher storage modulus (G') and loss modulus (G"), and had better ductility and deformability. Common wheat flour was partially replaced by modified flour to make steamed bread. The results indicated that the volume, height, diameter and specific volume of steamed bread were significantly decreased with the addition of HMT flour. However, the hardness, viscosity and chewiness increased significantly. The resistant starch content of steamed bread with the modified wheat flour increased. The results provide new insights for the development of new functional steamed bread.

18.
Front Nutr ; 9: 951588, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36034897

RESUMO

In this study, wheat flour (WF) was modified by annealing (ANN) using plasma-activated water (PAW) for the first time. Compared with WF and DW-WF, the results of scanning electron microscopy (SEM) and particle-size analysis showed that the granule structure of wheat starch in PAW-WF was slightly damaged, and the particle size of PAW-WF was significantly reduced. The results of X-ray diffraction and Fourier transforming infrared spectroscopy indicated that PAW-ANN could reduce the long-range and short-range order degrees of wheat starch and change the secondary structure of the protein in WF, in which the content of random coils and α-helices was significantly increased. In addition, the analysis of solubility, viscosity, and dynamic rheological properties showed that PAW-ANN improved the solubility and gel properties of WF and decreased its viscosity properties and short-term regeneration. PAW-ANN, as a green modification technology, has the potential for further application in WF modification, as well as in the production of flour products.

19.
Front Nutr ; 9: 965073, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35923195

RESUMO

Dendrobium officinale Kimura et Migo (D. officinale) is a traditional medicinal and food homologous plant that has been used for thousands of years in folk medicine and nutritious food. Recent studies have shown that polysaccharide is one of the main biologically active components in D. officinale. D. officinale polysaccharides possess several biological activities, such as anti-oxidant, heptatoprotective, immunomodulatory, gastrointestinal protection, hypoglycemic, and anti-tumor activities. In the past decade, polysaccharides have been isolated from D. officinale by physical and enzymatic methods and have been subjected to structural characterization and activity studies. Progress in extraction, purification, structural characterization, bioactivity, structure-activity relationship, and possible bioactivity mechanism of polysaccharides D. officinale were reviewed. In order to provide reference for the in-depth study of D. officinale polysaccharides and the application in functional food and biomedical research.

20.
J Org Chem ; 76(16): 6849-55, 2011 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-21755978

RESUMO

A highly efficient synthesis of trans-alkenylazaarene under catalyst-free conditions was developed via the addition of methylazaarenes to N-sulfonyl aldimines and a subsequent C-N elimination in situ. A one-pot procedure for this addition-elimination was also developed. The reaction could tolerate a broad substrate scope and give the corresponding alkenylazaarenes in high yields.

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