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1.
Int J Biol Macromol ; 262(Pt 2): 130028, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38340927

RESUMO

Porous morphology and mechanical properties determine the applications of cryogels. To understand the influence of the ionic network on the microstructure and mechanical properties of pectin cryogels, we prepared low-methoxyl pectin (LMP) cryogels with different Ca2+ concentrations (measured as R-value, ranging from 0 to 2) through freeze-drying (FD). Results showed that the R-values appeared to be crucial parameters that impact the pore morphology and mechanical characteristics of cryogels. It is achieved by altering the network stability and water state properties of the cryogel precursor. Cryogel precursors with a saturated R-value (R = 1) produced a low pore diameter (0.12 mm) microstructure, obtaining the highest crispness (15.00 ± 1.85) and hardness (maximum positive force and area measuring 2.36 ± 0.31 N and 12.30 ± 1.57 N·s respectively). Hardness showed a negative correlation with Ca2+ concentration when R ≤ 1 (-0.89), and a similar correlation with the porosity of the gel network when R ≥ 1 (-0.80). Given the impacts of crosslinking on the pore structure, it is confirmed that the pore diameter can be designed between 56.24 and 153.58 µm by controlling R-value in the range of 0-2.


Assuntos
Criogéis , Pectinas , Criogéis/química , Fenômenos Mecânicos , Porosidade , Dureza
2.
ACS Appl Mater Interfaces ; 15(29): 34578-34587, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37439604

RESUMO

Monitoring the force of fingertip manipulation without disturbing the natural sense of touch is crucial for digitizing the skills of experienced craftsmen. However, conventional force sensors need to be put between the skin and the objects, which affects the natural sense of the skin. Here, we proposed a fingertip force sensing method based on changes of blood volume and designed a wearable photoelectric fingertip force sensing system (PFFS) for digitalization of traditional Chinese medicine (TCM) pulse diagnosis. The PFFS does not interfere with the fingertips' tactile sense while detecting fingertip force. This PFFS detects the change of blood volume in fingertip by photoelectric plethysmography and can obtain the change of output current under different fingertip forces. We also studied the effect of various factors on PFFS output signals, including emission lights of different wavelengths, ambient temperature, and the user's heartbeat artifact. We further established the relationship between the change of blood volume and fingertip force by combining experimental and theoretical methods. Moreover, we demonstrated the feasibility of the PFFS to detect fingertip forces under commonly used conditions in TCM pulse diagnosis without sensory interference. This PFFS also shows promise for perceiving the viscosity of objects and recognizing gestures in human-computer interaction. This work paves the way for the digitalization of fingertip forces during TCM pulse diagnosis and other fingertip forces under natural conditions.


Assuntos
Dedos , Dispositivos Eletrônicos Vestíveis , Humanos , Tato , Fenômenos Mecânicos , Volume Sanguíneo
3.
J Sci Food Agric ; 103(3): 1514-1521, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36184832

RESUMO

BACKGROUND: Carrots are widely used in home cooking and vegetable processing industries because of their high nutritional value. However, different processing methods may produce a negative impact on carrot texture and nutrition quality. Therefore, the development of better processing methods to preserve the texture and nutrition quality of carrots will be beneficial to the carrot industry. RESULTS: The effects of heat and pulsed electric field (PEF) treatments with different heat temperatures (T) and holding time (th ) on comprehensive changes in thermal efficiency profiles, and physicochemical (color, hardness, cell structural damage) and nutritional (releasable ß-carotene contents) properties of carrots were studied. In addition, electrical conductivity (σ) and soluble matter contents (°Brix) were determined for the heat-treated extracts. The value of total color difference (∆E) and cell structural damage index (Z) of carrots, σ and °Brix of extracts all increased with increasing T and th under different heat experimental conditions, whereas the value of cutting force (F) presented an opposite tendency and content of releasable ß-carotene decreased after th > 2 min at T = 100 °C. CONCLUSION: The results show that PEF heating is beneficial in preventing changes in physicochemical and nutritional properties of carrots compared to traditional heat treatment. PEF has potential as a heating technology in the food industry. © 2022 Society of Chemical Industry.


Assuntos
Daucus carota , Temperatura Alta , Daucus carota/química , beta Caroteno/análise , Culinária , Fenômenos Mecânicos , Manipulação de Alimentos/métodos
4.
Molecules ; 27(4)2022 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-35209022

RESUMO

Today, the use of natural biodegradable materials in the production processes is more and more adopted by industry to achieve cyclic economy targets and to improve environmental and human health indexes. Active packaging is the latest trend for food preservation. In this work, nanostructures were prepared by incorporation of thyme oil with natural natrium-montmorillonite and organo-montmorillonite with two different techniques, direct impregnation and the green evaporation-adsorption process. Such nanostructures were mixed with poly-L-lactic-acid for the first time via an extrusion molding process to develop a new packaging film. Comparisons of morphological, mechanical, and other basic properties for food packaging were carried out via XRD, FTIR, TG, SEM/EDS, oxygen and water vapor permeation, and antimicrobial and antioxidant activity for the first time. Results showed that poly-L-lactic-acid could be modified with clays and essential oils to produce improved active packaging films. The final product exhibits food odor prevention characteristics and shelf-life extension capabilities, and it could be used for active packaging. The films based on OrgMt clay seems to be more promising, while the thyme oil addition improves their behavior as active packaging. The PLLA/3%TO@OrgMt and PLLA/5%TO@OrgMt films were qualified between the tested samples as the most promising materials for this purpose.


Assuntos
Antioxidantes/química , Bentonita/química , Embalagem de Alimentos , Membranas Artificiais , Nanoestruturas/química , Óleos de Plantas/química , Poliésteres/química , Sódio/química , Timol/química , Thymus (Planta)/química , Anti-Infecciosos , Fenômenos Químicos , Fenômenos Mecânicos , Nanoestruturas/ultraestrutura , Análise Espectral
5.
Adv Sci (Weinh) ; 9(11): e2104969, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35170258

RESUMO

Human-robot collaboration is playing more and more important roles in current deployments of robotic systems in our lives. Haptic perception and intelligent control are essential to ensure safety and efficiency of human-robot interaction. However, existing robotic sensory and control systems are deficient in terms of performance issues, complexity, and cost. Here, the authors report a multifunctional electronic skin (e-skin) incorporating multiple perceptions with intelligent robotic control, by which robots can safely and dexterously interact with humans. The e-skin with a simple and cost-effective sensory structure has multimodal perceptions of proximity, temperature, contact force, and contact position with broad measuring range, high sensitivity, and fast response. The e-skin is applied onto robots to accomplish obstacle avoidance, safe and dexterous human-robot interaction, smart teaching, and playing Tai-Chi, which demonstrate a broad range of applications for intelligent robots equipped with e-skins.


Assuntos
Robótica , Dispositivos Eletrônicos Vestíveis , Humanos , Fenômenos Mecânicos , Pele
6.
Int J Biol Macromol ; 194: 32-41, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34863831

RESUMO

Banana (Musa acuminata) pseudostem cellulose was extracted and acetylated (CA) to prepare membranes with potential use as bio-packages. The CA membrane was embedded by Butia seed (CA-BS) or Butia pulp (CA-BP) extracts obtained from Butia catarinenses (Butia). The produced CA, CA-BS, and CA-BP membranes were evaluated for their physical-chemical, mechanical, thermal, and antibacterial properties. The process for obtaining the cellulose yielded a material with about 92.17% cellulose (DS = 2.85). The purity, cellulose degree acetylation, and the incorporation of Butia extracts into the membranes were confirmed by FTIR. The CA-BS and CA-BP membranes showed a smaller contact angle and higher swelling ratio than the CA membrane. Furthermore, Butia seed or pulp extracts reduced the elastic modulus and deformation at break compared to the CA membrane. The DSC analysis suggested the compatibility between sections and the CA matrix, whereas the TGA analysis confirmed the thermal stability of the membranes. Moreover, less than 1% of the Butia seed and pulp extracts were put into a food simulant media from the membrane. Finally, the CA-BS and CA-BP membranes could inhibit the growth of Staphylococcus aureus and Escherichia coli on their surface, confirming the potential use of these membranes as bio-packaging for food preservation.


Assuntos
Celulose/análogos & derivados , Musa/química , Extratos Vegetais/química , Caules de Planta/química , Antibacterianos/química , Antibacterianos/farmacologia , Celulose/química , Fenômenos Químicos , Fenômenos Mecânicos , Membranas Artificiais , Embalagem de Produtos , Análise Espectral
7.
Int J Biol Macromol ; 192: 1123-1133, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655591

RESUMO

A novel active food packaging film was developed by casting a corn starch/tea polyphenol (TP)-loaded porous starch (PS, obtained by enzymatic hydrolysis) film forming solution, with the latter helping to regulate the slow release of TP. Results showed that PS had a favorable TP adsorption capacity, and the casted films had a homogeneous distribution of the formulation components. Likewise, the active films had good mechanical properties, UV barrier properties, thermal stability, and excellent antioxidant properties. The slow release of TP from the films was sustained, which is a desired characteristic for extending the protection afforded by the active film to the food under consideration.


Assuntos
Embalagem de Alimentos , Membranas Artificiais , Polifenóis/química , Amido/química , Chá/química , Antioxidantes/química , Antioxidantes/farmacologia , Fenômenos Químicos , Fenômenos Mecânicos , Estrutura Molecular , Permeabilidade , Extratos Vegetais/química , Polifenóis/farmacologia , Porosidade , Análise Espectral , Vapor , Termogravimetria
8.
Int J Biol Macromol ; 192: 479-490, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34648799

RESUMO

A sustainable multifunctional food packaging composite film containing waste garlic peel extract (GPE) and Chitosan (CH) was prepared. This film exhibited antimicrobial potential towards Staphylococcus aureus and Klebsiella pneumoniae. GPE/CH films' morphological, physical, and functional properties were compared to those of CH film. Fourier transform infrared showed the interactions through hydrogen bonding between CH and GPE in the blends that improved the polymers' compatibility. Furthermore, X-ray diffraction analysis validated the compatibility between GPE and CH. GPE/CH films exhibited higher thickness and moisture content than the CH film. Remarkably, GPE/CH films showed lower water vapor barrier properties and higher ultra-violet protection and mechanical strength than CH film. Compact surfaces of the GPE infused CH films were unveiled through Scanning electron microscopy. GPE/CH film showed improved thermal stability after the addition of GPE. MTT method's cytotoxicity study manifested that the GPE/CH films are antioxidant and non-cytotoxic, implicating their biocompatibility and non-toxicity. The results suggest that GPE/CH films can find widespread commercial applications like food packaging materials, replacing the commonly used petrochemical plastics.


Assuntos
Quitosana/química , Embalagem de Alimentos , Alho/química , Membranas Artificiais , Extratos Vegetais/química , Resíduos , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Materiais Biocompatíveis/química , Biopolímeros/química , Fenômenos Químicos , Fenômenos Mecânicos , Testes de Sensibilidade Microbiana , Permeabilidade , Análise Espectral , Vapor , Termogravimetria
9.
Int J Biol Macromol ; 192: 1160-1168, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34678378

RESUMO

Antioxidant and antimicrobial chitosan (CS) films incorporated with different concentrations (0, 3, 6 and 9% w/w based on chitosan) of pomegranate peel powder (PPP) were prepared through a simple and low-cost process and characterized. The physicochemical property, antioxidant and antibacterial properties of the films were investigated. Results showed that incorporation with PPP increased the thickness, water solubility (WS), water vapor permeability (WVP), opacity and total phenolic content (TPC) of chitosan films, but decreased the moisture content (MC) and mechanical property. Fourier transform infrared (FTIR) spectroscopy indicated the formation of hydrogen bonds between chitosan and PPP. In addition, scanning electron microscopy (SEM) analysis presented that microstructural attributes of chitosan film changed by enriching with pomegranate peel. The films with concentrations of PPP at 6 and 9% presented great ultraviolet-visible light barrier properties. Moreover, the antioxidant ability of films with PPP was significantly increased compared to the chitosan film. The addition of PPP also promoted the antibacterial capacity of the control film. These results revealed that incorporation of PPP in chitosan film could fabricate an economical active film with antioxidant and antibacterial properties, and which had the potential for developing food-grade packaging material.


Assuntos
Quitosana/química , Embalagem de Alimentos , Membranas Artificiais , Extratos Vegetais/química , Punica granatum/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Relação Dose-Resposta a Droga , Fenômenos Mecânicos , Testes de Sensibilidade Microbiana , Permeabilidade , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Solubilidade , Vapor
10.
Int J Biol Macromol ; 192: 627-634, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626727

RESUMO

The study aimed to obtain chitosan composite films with gratifying physical and functional properties. First, we developed a Pickering emulsion containing clove essential oil (CEO)-loaded nanoparticles with 1:2 (w/w) zein and sodium caseinate (NaCas). We found that in this ratio, the CEO-loaded zein-NaCas (C/ZN) nanoparticles had smaller particle size, proper polydispersity index (PDI) and zeta potential as well as higher encapsulation efficiency. Then, the acquired C/ZN nanoparticles were incorporated into chitosan film at three levels (0.2%, 0.4% and 0.6%), reducing the water vapor permeability to 4.62 × 10-6 g·s-1·m-1·Pa. Also, the tensile strength and break elongation of chitosan films were increased, reaching 38.67 MPa and 1.56%, respectively. The infrared spectroscopy verified that the intermolecular hydrogen bonds exist between chitosan and C/ZN nanoparticles. The chitosan composite films showed a controlled-release property of CEO in 96 h. Finally, the chitosan composite films showed the improved antibacterial property by creating larger inhibition zones against Escherichia coli (3.29 mm) and Staphylococcus aureus (6.15 mm). In general, we improved the water resistance, light blocking, mechanical strength, controlled-release and antibacterial properties of chitosan film with C/ZN nanoparticles. The current edible antibacterial films have great potential on applications for food preservation and food delivery system.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Óleo de Cravo/química , Embalagem de Alimentos , Óleos Voláteis/química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Fenômenos Químicos , Emulsões , Conservação de Alimentos , Teste de Materiais , Fenômenos Mecânicos , Nanopartículas/química , Tamanho da Partícula , Permeabilidade , Análise Espectral , Vapor
11.
Eur J Pharm Biopharm ; 169: 29-36, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34508806

RESUMO

The influence of mechanical skin treatments (massage, ultrasound, microdermabrasion, tape stripping and microneedling) on the dermal penetration efficacy was investigated. Results show that microneedling was the most effective tool. It increased the penetration efficacy (amount of penetrated active and penetration depth) by a factor > 2. Microdermabrasion and tape stripping remove parts of the stratum corneum (SC). This reduces the barrier function and increases the penetration efficacy. Microdermabrasion removed about 23% of the SC. Tape stripping removed about 34% of the SC and thus resulted in a slightly more pronounced increase in the penetration efficacy (+31% after tape stripping and +18% after microdermabrasion). Massage and skin treatment with ultrasound decreased the penetration efficacy by about one third when compared to skin where the formulations were applied without any mechanical treatment. The penetration reducing effect is caused by mechanical stress (pressure), which reduces the thickness of the SC. The increased density of the SC is considered to decrease the intercellular space within the SC and with this the flux for chemical compounds. Therefore, massage and other mechanical treatments that increase the density of the SC should be avoided if efficient dermal penetration is required.


Assuntos
Administração Cutânea , Formas de Dosagem , Sistemas de Liberação de Medicamentos , Absorção Cutânea/fisiologia , Fenômenos Fisiológicos da Pele , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Epiderme/diagnóstico por imagem , Epiderme/fisiologia , Humanos , Massagem/métodos , Fenômenos Mecânicos , Agulhas , Ultrassonografia/métodos
12.
Carbohydr Polym ; 270: 118317, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34364590

RESUMO

Arabinoxylan (AX) and cellulose were extracted from wheat straw, whereas starch was extracted from potato peel. Thereafter, cellulose and starch were esterified with lauric, myristic, palmitic and stearic acids to prepare corresponding cellulose (CFAs) and starch fatty acid esters (SFAs) with DS 2.1-2.8. XRD study revealed remarkable loss of crystallinity in cellulose and starch due to fatty acid esterification. The addition of palmitate and stearate esters of cellulose and starch to AX formed laminar film microstructures which limited water vapor permeability whereas films prepared by blending AX with laurate and myristate esters of starch and cellulose were less effective as water vapor barrier due to their non-layer microstructures. The laminar structures also resulted significant reduction in mechanical strength of the composite films. Furthermore, all AX-CFAs and AX-SFAs films were thermally more stable than native composite films. These films might be used to produce industrially useful coating material for food products.


Assuntos
Celulose/química , Ácidos Graxos/química , Amido/química , Xilanos/química , Esterificação , Ésteres/química , Embalagem de Alimentos/métodos , Humanos , Fenômenos Mecânicos , Microscopia Eletrônica de Varredura/métodos , Permeabilidade , Fenômenos Físicos , Solanum tuberosum/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Vapor , Ácidos Esteáricos/química , Termogravimetria/métodos , Triticum/química , Água/química
13.
Molecules ; 26(16)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34443359

RESUMO

Beet has been used as an ingredient for functional foods due to its high antioxidant activity, thanks to the betalains it contains. The effects of the addition of beet extract (liquid and lyophilized) on the physicochemical characteristics, color, antioxidant activity (AA), total betalains (TB), total polyphenols (TP), and total protein concentration (TPC) were evaluated on stirred yogurt. The treatments (T1-yogurt natural, T2-yogurt added with beet juice, T3-added extract of beet encapsulated with maltodextrin, and T4-yogurt added with extract of beet encapsulated with inulin) exhibited results with significant differences (p < 0.05). The highest TB content was observed in T2 (209.49 ± 14.91), followed by T3 (18.65 ± 1.01) and later T4 (12.96 ± 0.55). The highest AA was observed on T2 after 14 days (ABTS˙ 0.819 mM TE/100 g and DPPH˙ 0.343 mM TE/100 g), and the lowest was found on T1 at day 14 (ABTS˙ 0.526 mM TE/100 g and DPPH˙ 0.094 mM TE/100 g). A high content of TP was observed (7.13 to 9.79 mg GAE/g). The TPC varied between 11.38 to 12.56 µg/mL. The addition of beet extract significantly increased AA in yogurt, betalains being the main compounds responsible for that bioactivity.


Assuntos
Antioxidantes/química , Beta vulgaris/química , Extratos Vegetais/química , Iogurte/análise , Cápsulas , Fenômenos Químicos , Manipulação de Alimentos , Fenômenos Mecânicos
14.
Molecules ; 26(14)2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34299524

RESUMO

The use of chemical modification of cellulosic fibre is applied in order to increase the hydrophobicity, hence improving the compatibility between the fibre and matrix bonding. In this study, the effect of propionic anhydride modification of kenaf fibre was investigated to determine the role of bionanocarbon from oil palm shell agricultural wastes in the improvement of the functional properties of bionanocomposites. The vinyl esters reinforced with unmodified and propionic anhydride modified kenaf fibres bio nanocomposites were prepared using 0, 1, 3, 5 wt% of bio-nanocarbon. Characterisation of the fabricated bionanocomposite was carried out using FESEM, TEM, FT-IR and TGA to investigate the morphological analysis, surface properties, functional and thermal analyses, respectively. Mechanical performance of bionanocomposites was evaluated according to standard methods. The chemical modification of cellulosic fibre with the incorporation of bionanocarbon in the matrix exhibited high enhancement of the tensile, flexural, and impact strengths, for approximately 63.91%, 49.61% and 54.82%, respectively. The morphological, structural and functional analyses revealed that better compatibility of the modified fibre-matrix interaction was achieved at 3% bionanocarbon loading, which indicated improved properties of the bionanocomposite. The nanocomposites exhibited high degradation temperature which signified good thermal stability properties. The improved properties of the bionanocomposite were attributed to the effect of the surface modification and bionanocarbon enhancement of the fibre-matrix networks.


Assuntos
Anidridos/química , Celulose/química , Hibiscus/química , Nanocompostos/química , Propionatos/química , Carbono/química , Fenômenos Mecânicos , Óleo de Palmeira/química , Resistência à Tração
15.
Mar Drugs ; 19(5)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069393

RESUMO

Ultrasound-assisted water extraction was optimized to recover gelling biopolymers and antioxidant compounds from Mastocarpus stellatus. A set of experiments following a Box-Behnken design was proposed to study the influence of extraction time, solid liquid ratio, and ultrasound amplitude on the yield, sulfate content, and thermo-rheological properties (viscoelasticity and gelling temperature) of the carrageenan fraction, as well as the composition (protein and phenolic content) and antiradical capacity of the soluble extracts. Operating at 80 °C and 80 kHz, the models predicted a compromise optimum extraction conditions at ~35 min, solid liquid ratio of ~2 g/100 g, and ultrasound amplitude of ~79%. Under these conditions, 40.3% carrageenan yield was attained and this product presented 46% sulfate and good mechanical properties, a viscoelastic modulus of 741.4 Pa, with the lowest gelling temperatures of 39.4 °C. The carrageenans also exhibited promising antiproliferative properties on selected human cancer cellular lines, A-549, A-2780, HeLa 229, and HT-29 with EC50 under 51.9 µg/mL. The dried soluble extract contained 20.4 mg protein/g, 11.3 mg gallic acid eq/g, and the antiradical potency was equivalent to 59 mg Trolox/g.


Assuntos
Carragenina/isolamento & purificação , Carragenina/farmacologia , Proliferação de Células/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Rodófitas/química , Antioxidantes/química , Carragenina/análise , Carragenina/química , Linhagem Celular Tumoral , Géis , Humanos , Fenômenos Mecânicos , Fenóis/química , Extratos Vegetais/análise , Extratos Vegetais/química , Reologia , Sulfatos/análise , Temperatura , Ondas Ultrassônicas , Viscosidade , Água/química
16.
Phys Chem Chem Phys ; 23(25): 14093-14108, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34159985

RESUMO

Mapping the topological phase behaviour of lipids in aqueous solution is time consuming and finding the ideal lipid system for a desired application is often a matter of trial and error. Modelling techniques that can accurately predict the mesomorphic phase behaviour of lipid systems are therefore of paramount importance. Here, the self-consistent field theory of Scheutjens and Fleer (SF-SCF) in which a lattice refinement has been implemented, is used to scrutinize how various additives modify the self-assembled phase behaviour of monoolein (MO) and 1,2-dioleoyl-phosphatidylcholine (DOPC) lipids in water. The mesomorphic behaviour is inferred from trends in the mechanical properties of equilibrium lipid bilayers with increasing additive content. More specifically, we focus on the Helfrich parameters, that is, the mean and Gaussian bending rigidities (κ and [small kappa, Greek, macron], respectively) supplemented with the spontaneous curvature of the monolayer (Jm0). We use previously established interaction parameters that position the unperturbed DOPC system in the lamellar Lα phase ([small kappa, Greek, macron] < 0, κ > 0 and Jm0 ≈ 0). Similar interaction parameters position the MO system firmly in a bicontinuous cubic phase ([small kappa, Greek, macron] > 0). In line with experimental data, a mixture of MO and DOPC tends to be in one of these two phases, depending on the mixing ratio. Moreover we find good correlations between predicted trends and experimental data concerning the phase changes of MO in response to a wide range of additives. These correlations give credibility to the use of SF-SCF modelling as a valuable tool to quickly explore the mesomorphic phase space of (phospho)lipid bilayer systems including additives.


Assuntos
Glicerídeos/química , Bicamadas Lipídicas/química , Fosfatidilcolinas/química , Fenômenos Mecânicos , Modelos Moleculares , Distribuição Normal , Transição de Fase , Temperatura de Transição , Água
17.
Sci Rep ; 11(1): 12258, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-34112892

RESUMO

Glucocorticoids (GCs), such as prednisolone, are widely used to treat inflammatory diseases. Continuously long-term or high dose treatment with GCs is one of the most common causes of secondary osteoporosis and is associated with sarcopenia and increased risk of debilitating osteoporotic fragility fractures. Abaloparatide (ABL) is a potent parathyroid hormone-related peptide analog, which can increase bone mineral density (aBMD), improve trabecular microarchitecture, and increase bone strength. The present study aimed to investigate whether GC excess blunts the osteoanabolic effect of ABL. Sixty 12-13-week-old female RjOrl:SWISS mice were allocated to the following groups: Baseline, Control, ABL, GC, and GC + ABL. ABL was administered as subcutaneous injections (100 µg/kg), while GC was delivered by subcutaneous implantation of a 60-days slow-release prednisolone-pellet (10 mg). The study lasted four weeks. GC induced a substantial reduction in muscle mass, trabecular mineral apposition rate (MAR) and bone formation rate (BFR/BS), and endocortical MAR compared with Control, but did not alter the trabecular microarchitecture or bone strength. In mice not receiving GC, ABL increased aBMD, bone mineral content (BMC), cortical and trabecular microarchitecture, mineralizing surface (MS/BS), MAR, BFR/BS, and bone strength compared with Control. However, when administered concomitantly with GC, the osteoanabolic effect of ABL on BMC, cortical morphology, and cortical bone strength was blunted. In conclusion, at cortical bone sites, the osteoanabolic effect of ABL is generally blunted by short-term GC excess.


Assuntos
Densidade Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Fêmur , Glucocorticoides/administração & dosagem , Proteína Relacionada ao Hormônio Paratireóideo/farmacologia , Adipócitos/metabolismo , Animais , Biomarcadores , Doenças Ósseas Metabólicas/tratamento farmacológico , Doenças Ósseas Metabólicas/etiologia , Doenças Ósseas Metabólicas/metabolismo , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/patologia , Imuno-Histoquímica , Fenômenos Mecânicos , Camundongos , Osteócitos/metabolismo , Osteogênese/efeitos dos fármacos , Osteoporose/tratamento farmacológico , Osteoporose/etiologia , Osteoporose/metabolismo , Microtomografia por Raio-X
18.
Carbohydr Polym ; 268: 118244, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34127224

RESUMO

Self-healing hydrogels with pH-responsiveness could protect loaded drugs from being destroyed till it arrives to the target. The pectin-based hydrogel is a candidate due to the health benefit, anti-inflammation, antineoplastic activity, nontoxicity, and biospecific degradation, et al. However, the abundant existence of water-soluble branched heteropolysaccharide chains influenced its performance resulting in limitation of the potential. In the present study, we prepared a series of self-healing pectin/chitosan hydrogels via the Diels-Alder reaction. Moreover, pectin/chitosan composite hydrogel was prepared as a contrast. By comparison, it can be seen that the Diels-Alder reaction greatly improved the cross-linking density of hydrogels. The self-healing experiments showed excellent self-healing performance. In different swelling mediums, significant transformation in the swelling ratio was shown, indicating well-swelling property, pH- and thermo-responsiveness. The drug loading and release studies presented high loading efficiency and sustained release performance. The cytotoxicity assay that showed a high cell proliferation ratio manifested great cytocompatibility.


Assuntos
Quitosana/química , Portadores de Fármacos/química , Hidrogéis/química , Pectinas/química , Animais , Linhagem Celular , Quitosana/síntese química , Quitosana/toxicidade , Citrus/química , Reação de Cicloadição , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Fluoruracila/química , Furanos/síntese química , Furanos/química , Furanos/toxicidade , Hidrogéis/síntese química , Hidrogéis/toxicidade , Concentração de Íons de Hidrogênio , Cinética , Maleimidas/síntese química , Maleimidas/química , Maleimidas/toxicidade , Fenômenos Mecânicos , Camundongos , Pectinas/síntese química , Pectinas/toxicidade , Temperatura
19.
Exp Neurol ; 343: 113767, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34044000

RESUMO

Ischemic stroke is a leading cause of disability world-wide. Mounting evidence supports neuromuscular pathology following stroke, yet mechanisms of dysfunction and therapeutic action remain undefined. The objectives of our study were to investigate neuromuscular pathophysiology following ischemic stroke and to evaluate the therapeutic effect of Robot-Assisted Mechanical massage Therapy (RAMT) on neuromuscular junction (NMJ) morphology. Using an ischemic stroke model in male rats, we demonstrated longitudinal losses of muscle contractility and electrophysiological estimates of motor unit number in paretic hindlimb muscles within 21 days of stroke. Histological characterization demonstrated striking pre- and postsynaptic alterations at the NMJ. Stroke prompted enlargement of motor axon terminals, acetylcholine receptor (AChR) area, and motor endplate size. Paretic muscle AChRs were also more homogenously distributed across motor endplates, exhibiting fewer clusters and less fragmentation. Most interestingly, NMJs in paretic muscle exhibited increased frequency of polyaxonal innervation. This finding of increased polyaxonal innervation in stroke-affected skeletal muscle suggests that reduction of motor unit number following stroke may be a spurious artifact due to overlapping of motor units rather than losses. Furthermore, we tested the effects of RAMT - which we recently showed to improve motor function and protect against subacute myokine disturbance - and found significant attenuation of stroke-induced NMJ alterations. RAMT not only normalized the post-stroke presentation of polyaxonal innervation but also mitigated postsynaptic expansion. These findings confirm complex neuromuscular pathophysiology after stroke, provide mechanistic direction for ongoing research, and inform development of future therapeutic strategies. SIGNIFICANCE: Ischemic stroke is a leading contributor to chronic disability, and there is growing evidence that neuromuscular pathology may contribute to the impact of stroke on physical function. Following ischemic stroke in a rat model, there are progressive declines of motor unit number estimates and muscle contractility. These changes are paralleled by striking pre- and postsynaptic maladaptive changes at the neuromuscular junction, including polyaxonal innervation. When administered to paretic hindlimb muscle, Robot-Assisted Mechanical massage Therapy - previously shown to improve motor function and protect against subacute myokine disturbance - prevents stroke-induced neuromuscular junction alterations. These novel observations provide insight into the neuromuscular response to cerebral ischemia, identify peripheral mechanisms of functional disability, and present a therapeutic rehabilitation strategy with clinical relevance.


Assuntos
Axônios/fisiologia , Isquemia Encefálica/reabilitação , AVC Isquêmico/reabilitação , Manipulações Musculoesqueléticas/instrumentação , Junção Neuromuscular/fisiologia , Robótica/instrumentação , Animais , Isquemia Encefálica/fisiopatologia , AVC Isquêmico/fisiopatologia , Masculino , Fenômenos Mecânicos , Contração Muscular/fisiologia , Manipulações Musculoesqueléticas/métodos , Ratos , Ratos Wistar , Robótica/métodos
20.
Int J Biol Macromol ; 182: 1820-1831, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34052272

RESUMO

Developing a multifunctional wound dressing that protects, cures and indicates the healing progress, is a new approach of investigation. Red cabbage extract (RCE), consisting of bioactive compounds that have antioxidant, anti-inflammatory, anti-carcinogenic, bactericidal, antifungal, and antiviral activities, was utilized as a natural pH-sensitive indicator. Chitosan-based hydrogel, encapsulating RCE, was developed to obtain a smart therapeutic pH-sensitive wound dressing as antimicrobial bio-matrix provides a comfortable cushion for wound bed and indicates its status. Methacrylated-chitosan was crosslinked by different concentrations of methylenebisacrylamide (MBAA) by which hydrogel mechanical and morphological properties were tuned. The proposed mechanism for hydrogel formation was confirmed by FT-IR. The coloristic properties of the RCE and the changes in color intensity as a function of pH were confirmed by UV-Vis spectroscopy. The effect of MBAA on the mechanical, swelling, release and morphological properties of hydrogel were investigated. MBAA (2.5% wt/v) in 2% wt/v chitosan showed preferable mechanical (20 KPa), swelling (1294% at pH 8 ± 0.2), and release (prolonged up to 5 days) properties. Hydrogel matrices, loaded on cotton gauze submerged in different pH buffer solutions, showed explicit color changes from green to red as pH changed from 9 to 4.


Assuntos
Bandagens , Brassica/química , Quitosana/farmacologia , Hidrogéis/farmacologia , Extratos Vegetais/farmacologia , Cicatrização/efeitos dos fármacos , Acrilamidas/química , Antocianinas/análise , Quitosana/química , Colorimetria , Concentração de Íons de Hidrogênio , Fenômenos Mecânicos , Porosidade , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
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