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1.
Chemosphere ; 258: 127388, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947665

RESUMO

Microplastics enter natural water bodies by a variety of pathways, one of them being wastewater streams. The role of industrial wastewater in overall microplastic emissions has so far only been estimated, because access is usually restricted. This is the first report providing quantitative data on microplastics in industrial wastewaters. The wastewater discharge of three different industrial sites was sampled in the size ranges of small microplastics (10-1000 µm) and large microplastics (1000-5000 µm). Differential scanning calorimetry (DSC) was used to detect and quantify semi-crystalline thermoplastics. Polyethylene (PE) and polypropylene (PP) were the most abundant polymers, but polyamide (PA) and polyethylene terephthalate (PET) were also found. As all three industrial sites had wastewater treatment plants (WWTP), the total concentrations were in the µg L-1 range, comparable to organic micropollutants in municipal WWTP effluents. At one industrial site, the removal capacity of the WWTP was evaluated by sampling and analyzing the influent as well as the effluent. The total microplastics concentration in the influent was in the g L-1 range, yielding a removal capacity of the industrial WWTP of >99.99 %.


Assuntos
Monitoramento Ambiental , Microplásticos/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Varredura Diferencial de Calorimetria , Resíduos Industriais/análise , Indústrias , Plásticos , Polietileno , Polímeros , Polipropilenos
2.
J Chromatogr A ; 1627: 461380, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823093

RESUMO

Microwave-ultrasonic assisted aqueous enzymatic extraction (MUAAEE) was applied to extract tiger nut oil (TNO). The conditions of MUAAEE were optimized by Plackett-Burman design followed Box-Behnken design. An oil recovery of 85.23% was achieved under optimum conditions of a 2% concentration of mixed enzyme including cellulase, pectinase and hemicellulase (1/1/1, w/w/w), particle size <600 µm, microwave power 300 W, ultrasonic power 460 W, radiation temperature 40 °C, time 30 min, enzymolysis temperature 45 °C, pH 4.9, liquid-to-solid ratio 10 mL/g and time 180 min. Oil by MUAAEE revealed the similar fatty acid compositions, triglyceride compositions, thermal behaviour and flavour compared with oil by Soxhlet extraction (SE), while the oil quality of MUAAEE is superior to that of SE. Scanning electron microscopy revealed that structural disruption of tiger nut caused by MUAAEE facilitated the oil extraction. Results suggest that MUAAEE could be an efficient and environment-friendly method for extraction of TNO.


Assuntos
Cyperus/química , Enzimas/metabolismo , Micro-Ondas , Nozes/química , Óleos Vegetais/química , Ultrassom , Varredura Diferencial de Calorimetria , Celulase/metabolismo , Análise Discriminante , Ácidos Graxos/química , Glicosídeo Hidrolases/metabolismo , Poligalacturonase/metabolismo , Análise de Componente Principal , Reprodutibilidade dos Testes , Temperatura , Triglicerídeos/análise , Água/química
3.
Int J Nanomedicine ; 15: 4225-4236, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606674

RESUMO

Introduction: The aim of the study was to optimize the processing factors of precipitation-ultrasonication technique to prepare nano-sized particles of Lovastatin (LA) for enhancing its solubility, dissolution rate and in vivo bioavailability. Methods: LA nanoparticles (LANs) were prepared using precipitation-ultrasonication technique under different processing factors. LANs were characterized in terms of particle size, zeta potential and in vitro release. Stability studies at 4°C, 25°C and 40°C were conducted for optimum formulation. In addition, the in vivo bioavailability of the optimum formula was studied in comparison to a marketed product in white master rats. Results: The optimized LAN formula (LAN15) had particle size (190±15), polydispersity index (0.626±0.11) and a zeta potential (-25±1.9 mV). The dissolution study of the nanosuspensions showed significant enhancement compared with pure drug. After 50 min, only 20.12±1.85% of LA was dissolved while 99.1±1.09% of LA was released from LAN15. Stability studies verified that nanosuspensions at 4°C and 25°C showed higher stability with no particle growth compared to the samples studied at 40°C. In vivo studies conducted in rats verified that there was 1.45-fold enhancement of Cmax of LAN15 as compared to marketed tablets. Conclusion: Nanoparticle prepared by ultrasonication-assisted precipitation method is a promising formula for enhancing the solubility and hence the bioavailability of Lovastatin.


Assuntos
Lovastatina/farmacologia , Nanopartículas/química , Administração Oral , Animais , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Lovastatina/sangue , Lovastatina/química , Lovastatina/farmacocinética , Masculino , Tamanho da Partícula , Ratos Wistar , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Suspensões
4.
Int J Nanomedicine ; 15: 3965-3980, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606658

RESUMO

Aim: Etoricoxib is a selective inhibitor of COX-2 enzyme. It is proposed as a potent anti-inflammatory drug intended for the control of irritable bowel syndrome. The current work aimed at developing etoricoxib-loaded nanoparticles for colon- targeting. Materials and Methods: PLGA nanoparticles were developed via nano-spray drying technique. The D-optimal design was adopted for the investigation of the influence of i) DL-lactide-coglycolide (PLGA) concentration, ii) polyvinylpyrrolidone K30 (PVP K30) concentration and iii) lactide:glycolide ratio in the copolymer chain on the yield%, the encapsulation efficiency (EE%), particle size (PS) and percentage of drug release after 2h (P2h), 4h (P4h) and 12h (P12h). To promote colon targeting of the systems, the best achieved system (M14) was either directly coated with poly(methacrylic acid-co-methyl methacrylate) [Eudragit®-S100] or loaded into hard gelatin capsules and the capsules were coated with poly(methacrylic acid-co-methyl methacrylate) (E-M14C). The pharmacokinetic parameters of etoricoxib following oral administration of E-M14C in healthy volunteers were assessed relative to commercial etoricoxib tablets. Results: M14 system was prepared using PLGA (0.5% w/v) at a lactide:glycolide ratio of 100:0, in the presence of PVP K30 (2% w/v). M14 system was nano-spherical particles of 488 nm size possessing promising yield% (63.5%) and EE% (91.2%). The percentage drug released after 2, 4 and 12 hours were 43.41%, 47.34 and 64.96%, respectively. Following M14-loading into hard gelatin capsules and coating with poly(methacrylic acid-co-methyl methacrylate) [Eudragit-S100], the respective P2h, P4h and P12h were 10.1%, 28.60% and 65.45%. Significant (p < 0.05) differences between the pharmacokinetic parameter of E-M14C in comparison with the commercial product were revealed with a delay in Tmax (from 2.5h to 6h), a prolongation in MRT0-∞ (from 24.4h to 34.7h) and an increase in the relative oral bioavailability (4.23 folds). Conclusion: E-M14C is a potential system for possible colon targeting of etoricoxib.


Assuntos
Colo/efeitos dos fármacos , Etoricoxib/farmacologia , Etoricoxib/farmacocinética , Voluntários Saudáveis , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Ácidos Polimetacrílicos/química , Administração Oral , Adulto , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Colo/metabolismo , Liberação Controlada de Fármacos , Humanos , Masculino , Nanopartículas/administração & dosagem , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Adulto Jovem
5.
Int J Nanomedicine ; 15: 4001-4020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606661

RESUMO

Background: Simvastatin (SMV), a hypocholesterolemic agent, suffers from very low bioavailability due to its poor aqueous solubility and extensive first-pass metabolism. Methods: Two SMV carrier systems, namely, polymeric drug inclusion complex (IC) and mixed micelles (MM) nanoparticles, were developed and loaded into mucoadhesive buccal films to enhance SMV bioavailability. The two carrier systems were characterized and their permeation across human oral epithelial cells (OEC) was studied. The effect of IC to MM ratio (X1) and the mucoadhesive polymer concentration (X2) on the cumulative percent of drug released, elongation percent and the mucoadhesive strength, from the prepared mucoadhesive films, were optimized. Ex vivo permeation across bovine mucosal tissue was investigated. The permeation parameters for the in vitro and ex vivo release data were calculated. Results: Complexation of SMV with hydroxypropyl beta-cyclodextrin (HP ß-CD) was superior to all other polymers as revealed by the equilibrium saturation solubility, stability constant, complexation efficiency and thermodynamic potential. SMV-HP ß-CD IC was utilized to develop a saturated polymeric drug solution. Both carrier systems showed enhanced permeation across OEC when compared to pure drug. X1 and X2 were significantly affecting the characteristics of the prepared films. The optimized mucoadhesive buccal film formulation loaded with SMV IC and drug MM nanoparticles demonstrated superior ex vivo permeation when compared to the corresponding pure drug buccal film, and the calculated permeation parameters confirmed this finding. Conclusion: Mucoadhesive buccal films containing SMV IC and drug MM can be used to improve drug bioavailability; however, additional pharmacokinetic and pharmacodynamic studies are required.


Assuntos
Portadores de Fármacos/química , Liberação Controlada de Fármacos , Mucosa Bucal/efeitos dos fármacos , Muco/química , Sinvastatina/farmacologia , 2-Hidroxipropil-beta-Ciclodextrina/química , Adesividade , Animais , Varredura Diferencial de Calorimetria , Bovinos , Sistemas de Liberação de Medicamentos , Humanos , Nanopartículas/química , Nanopartículas/ultraestrutura , Permeabilidade , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
An Acad Bras Cienc ; 92(2): e20181062, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32638867

RESUMO

The influence of magnesium on roasting vanadium slag was investigated by simulating the roasting process of vanadium by mixing V2O5 and MgO. The calcination products of V2O5 reacted with MgO at different temperatures which were characterized by X-ray diffraction (XRD), Thermogravimetry-differential scanning calorimetry (TG-DSC) and scanning electron microscope (SEM). There were two mass loss intervals, three endothermic peaks and one exothermic peak appearing during the reaction by the integrated thermal analysis as the temperature increased from room temperature to 1273.15 K. The samples of mixed V2O5 and MgO began to melt at 573.15 K and reacted at 773 K, and the shape of the particles changed from block to ovoid or irregular sphere at 773.15 K. With increasing the reaction temperature from 973.15 to 1073.15 K, the intermediate of VO2 was produced, and MgV2O6 was partially decomposed at 1073.15 K. During this process, the particle shape gradually returned to block shape. The conversion rate of vanadium is 99.4% with MgO of 1.65%.


Assuntos
Magnésio/química , Varredura Diferencial de Calorimetria , Minerais , Termogravimetria , Vanádio
7.
AAPS PharmSciTech ; 21(5): 181, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32607628

RESUMO

Cocrystals have gained a lot of consideration regarding its superior role in enhancement of solubility and dissolution of the included API. Cocrystals could be converted to coamorphous systems via different techniques like milling and quench cooling; however, the use of spray-drying technique has not been investigated before. So, the aim of this study was to explore the effect of spray drying on the amorphization of indomethacin/nicotinamide, INDNIC, as model cocrystals. Spray-drying operating parameters were optimized using the Taguchi design of experiment for maximum powder yield and low moisture content. The obtained INDNIC spray-dried cocrystals were characterized for their degree of crystallinity, morphology, moisture content, and dissolution performance. In addition, stability study was performed at different temperature and humidity conditions. Experimental design results delineate that spray-drying inlet temperature and cocrystal concentrations as the most influential factors for maximum powder yield and low moisture content. Powder X-ray diffraction and differential scanning calorimetry studies revealed the conversion of INDNIC cocrystals to a partial coamorphous or coamorphous structure without dissociation of INDNIC molecular structure. INDNIC coamorphous powders showed a significantly higher release of IND compared with cocrystals and remain physically stable for 2 months when stored in the refrigerator.


Assuntos
Dessecação/métodos , Estabilidade de Medicamentos , Indometacina/química , Niacinamida/química , Varredura Diferencial de Calorimetria , Composição de Medicamentos/métodos , Estrutura Molecular , Pós/química , Solubilidade , Difração de Raios X
8.
J Vis Exp ; (161)2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32716389

RESUMO

The analysis of thermal processes associated to the curing of adhesives and the study of mechanical behavior once cured, provide key information to choose the best option for any specific application. The proposed methodology for the curing characterization, based on thermal analysis and rheology, is described through the comparison of three commercial adhesives. The experimental techniques used here are Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Rheology. TGA provides information about the thermal stability and filler content, DSC allows the evaluation of some thermal events associated to the cure reaction and to thermal changes of the cured material when subjected to temperature changes. Rheology complements the information of the thermal transformations from a mechanical point of view. Thus, the curing reaction can be tracked through the elastic modulus (mainly the storage modulus), the phase angle and the gap. In addition, it is also shown that although DSC is of no use to study the curing of moisture curable adhesives, it is a very convenient method to evaluate the low temperature glass transition of amorphous systems.


Assuntos
Adesivos/química , Varredura Diferencial de Calorimetria , Módulo de Elasticidade , Teste de Materiais , Reologia , Termogravimetria
9.
Food Chem ; 329: 127213, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516713

RESUMO

Chitosan and whey protein isolate (WPI) conjugate films were prepared as a novel matrix for encapsulating and extending the postharvest shelf life of strawberries. Film forming solutions of chitosan, WPI, and chitosan-WPI conjugate were mixed with glycerol, casted for films at 60 ± 2 °C and assessed for their colour, water vapour and oxygen transfer rate, textural, functional groups and secondary structure, thermal, crystallinity, and antioxidant properties. Chitosan-WPI conjugate films were applied as an edible coating on strawberries, and studied for storage stability at 5 °C and 20 °C by assessing physical and biochemical parameters. A considerable reduction in colour indices, weight loss, pH and titratable acidity, reducing sugars, ascorbic acid, total phenolics, DPPH and ABTS assay was noted in the coated strawberries over the control at both the studied temperatures. The control strawberries had a shelf life of 5 and 3 days, whereas coating enhanced the shelf life of strawberries to 8 and 5 days when stored at 5 °C and 20 °C, respectively.


Assuntos
Quitosana/química , Conservação de Alimentos/métodos , Proteínas do Soro do Leite/química , Antioxidantes/química , Ácido Ascórbico/análise , Varredura Diferencial de Calorimetria , Cor , Fragaria/química , Fragaria/metabolismo , Frutas/química , Frutas/metabolismo , Glicerol/química , Concentração de Íons de Hidrogênio , Fenóis/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
10.
Nat Commun ; 11(1): 3250, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591525

RESUMO

Biocompatible polymers are widely used in tissue engineering and biomedical device applications. However, few biomaterials are suitable for use as long-term implants and these examples usually possess limited property scope, can be difficult to process, and are non-responsive to external stimuli. Here, we report a class of easily processable polyamides with stereocontrolled mechanical properties and high-fidelity shape memory behaviour. We synthesise these materials using the efficient nucleophilic thiol-yne reaction between a dipropiolamide and dithiol to yield an α,ß - unsaturated carbonyl moiety along the polymer backbone. By rationally exploiting reaction conditions, the alkene stereochemistry is modulated between 35-82% cis content and the stereochemistry dictates the bulk material properties such as tensile strength, modulus, and glass transition. Further access to materials possessing a broader range of thermal and mechanical properties is accomplished by polymerising a variety of commercially available dithiols with the dipropiolamide monomer.


Assuntos
Elastômeros/química , Fenômenos Mecânicos , Nylons/química , Materiais Inteligentes/química , Animais , Materiais Biocompatíveis/farmacologia , Varredura Diferencial de Calorimetria , Linhagem Celular , Masculino , Teste de Materiais , Camundongos , Nylons/síntese química , Polimerização , Ratos Sprague-Dawley , Estresse Mecânico , Compostos de Sulfidrila/química , Temperatura
11.
AAPS PharmSciTech ; 21(5): 163, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488738

RESUMO

The aim of this study was to evaluate a multicomponent complex (MC) between rifampicin (RIF), ß-cyclodextrin (ß-CD), and selected amino acids to enhance the solubility and antibiofilm activity of RIF. After performing phase-solubility studies that demonstrated a considerable increase in the solubility of RIF for the MC, the corresponding solid system was prepared by a freeze-drying method. Characterization of the MC was performed by Fourier transform-infrared spectroscopy, thermal analysis, powder X-ray diffraction, and scanning electron microscopy. Structural analyses evidenced molecular interactions between the components, resulting in a MC with amorphous solid features. Structural studies involving both experimental (i.e., 1H NMR) and theoretical (i.e., molecular modeling) methodologies demonstrated the inclusion of the RIF piperazine ring in the ß-CD cavity. The bioactivity of the MC measured against biofilms of Staphylococcus aureus showed a significant reduction in the metabolic activity of the bacterium. Overall, the studied MC exhibited promising properties for the development of pharmaceutical formulations to treat bacterial infections.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Rifampina/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Varredura Diferencial de Calorimetria , Composição de Medicamentos , Liofilização/métodos , Microscopia Eletrônica de Varredura , Pós , Rifampina/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X , beta-Ciclodextrinas/química
12.
Int J Nanomedicine ; 15: 3729-3740, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547025

RESUMO

Background: Duraplasty is one of the most critical issues in neurosurgical procedures because the defect of dura matter will cause many complications. Electrospinning can mimic the 3D structure of the natural extracellular matrix whose structure is similar to that of dura matter. Poly(L-lactic acid) (PLLA) has been used to fabricate dura matter substitutes and showed compatibility to dural tissue. However, the mechanical properties of the PLLA substitute cannot match the mechanical properties of the human dura mater. Methods and Results: We prepared stereocomplex nanofiber membranes based on enantiomeric poly(lactic acid) and poly(D-lactic acid)-grafted tetracalcium phosphate via electrospinning. X-ray diffraction results showed the formation of stereocomplex crystallites (SC) in the composite nanofiber membranes. Scanning electron microscope observation images showed that composites nanofibers with higher SC formation can keep its original morphologies after heat treatment, suggesting the heat resistance of composite nanofiber membranes. Differential scanning calorimeter tests confirmed that the melting temperature of composite nanofiber membranes was approximately 222°C, higher than that of PLLA. Tensile testing indicated that the ultimate tensile strength and the elongation break of the stereocomplex nanofiber membranes were close to human dura matter. In vitro cytotoxicity studies proved that the stereocomplex nanofiber membranes were non-toxic. The neuron-like differentiation of marrow stem cells on the stereocomplex nanofiber membranes indicated its neuron compatibility. Conclusion: The stereocomplex nanofiber membranes have the potential to serve as a dura mater substitute.


Assuntos
Materiais Biomiméticos/química , Dura-Máter/fisiologia , Nanofibras/química , Poliésteres/química , Animais , Fosfatos de Cálcio/química , Varredura Diferencial de Calorimetria , Diferenciação Celular , Linhagem Celular , Cristalização , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Camundongos , Nanofibras/ultraestrutura , Neurônios/citologia , Ratos Sprague-Dawley , Estereoisomerismo , Temperatura , Difração de Raios X
13.
Food Chem ; 330: 127154, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531630

RESUMO

Dextran-containing sourdough has been exploited in breadmaking, obtaining additive-free bread of high quality. Effect of dextran, weak acidification and their association on gluten dough structure, thermal properties and rheology was investigated. Electrophoresis (SDS-PAGE) showed that dextran and acids both lowered the band intensity in the high molecular weight area (Mw > 175 kDa) and size exclusion (SE-HPLC) revealed that weak acidification induced a decrease of 4.73% of the glutenin macropolymer (GMP) content. The higher free thiol (SH) was observed after dextran addition, further suggesting the hindered glutenin polymerization. Fourier transform infrared spectroscopy (FTIR) found that dextran and weak acidity caused increased ß-turn and decreased ß-sheet structures, suggesting a gluten of lower coherence and resistance to extension. Weakened thermal stability and viscoelasticity were subsequently detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic rheology. However, structural, thermal and rheological properties of the weakly acidified group were improved by the associated dextran.


Assuntos
Dextranos/química , Glutens/química , Varredura Diferencial de Calorimetria , Concentração de Íons de Hidrogênio , Polimerização , Reologia , Triticum/química , Viscosidade
14.
Food Chem ; 330: 127243, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521403

RESUMO

The influences of konjac glucomannan (KGM) on the water distribution of frozen dough and steamed bread quaility made from frozen dough were addressed in this study. Low Field Nuclear Magnetic Resonance (LF-NMR) analysis demonstrated that the less tightly bound water of the dough was transferred to tightly bound water with the increase of KGM. Differential Scanning Calorimetry (DSC) showed that the freezable water of the frozen dough was transferred to non-freezable water with increasing the amount of KGM. DSC and LF-NMR results indicated the water state in the frozen dough was consistent. The addition of KGM enhanced the height and whiteness of steamed bread, but it decreased springiness, cohesiveness and resilience of steamed bread. As the KGM substitution rate increased, the hardness of steamed bread first decreased and then increased. The steamed bread with 1.5% of KGM showed the best quality.


Assuntos
Pão/análise , Mananas/química , Água/química , Varredura Diferencial de Calorimetria , Congelamento , Dureza , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Vapor
15.
Chemosphere ; 258: 127179, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554002

RESUMO

Hydrophobic membranes for desalination and toxic organic pollutant removal have been fabricated using polyamide - PDMS (polydimethylsiloxane) chemistries in a one-step protocol. The curing of polyamide and PDMS are orthogonal and co-curing both networks imparts hydrophobicity to the thin film composite membranes. The membranes exhibit increased adsorption of pesticides from the feed water along with maintaining excellent salt rejection capability (97% NaCl rejection), thus giving the membranes a multifunctional character. Three toxic pesticides have been used in this study to demonstrate the viability of combining osmosis desalination technology with organic matter adsorption. The membranes also show excellent resistance to fouling by toxic pesticides (85% salt rejection vs 67% for commercial membranes in the presence of pesticides) and significantly improved chlorine tolerance (93.8% salt rejection vs 86.5% for commercial membranes after 20 h of exposure to sodium hypochlorite solution).


Assuntos
Cloro/química , Dimetilpolisiloxanos/química , Membranas Artificiais , Praguicidas/isolamento & purificação , Purificação da Água/instrumentação , Varredura Diferencial de Calorimetria , Interações Hidrofóbicas e Hidrofílicas , Nylons/química , Osmose , Espectrometria por Raios X , Termogravimetria , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
16.
PLoS One ; 15(6): e0234774, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569283

RESUMO

We developed and describe a differential scanning calorimetry method for calculating the initial crystallinity, change of crystallinity and crystallinity percentage of amorphous metal alloys as a function of temperature. Using thermodynamic enthalpies of amorphous, crystalline and partially devitrified specimens, our methodology is capable of determining crystallinity percentages as low as a few percent. Moreover, the linear relationship between the set (pre-determined) and calculated crystallinities of experimental samples indicates that there is no need to prepare calibration samples before measuring the crystallinity percentage of target samples. This technique also eliminates the need for expensive in situ accessories, such as those required in electron microscopy. Thus, the technique is highly relevant as a primary technique for characterization of devitrification behavior in amorphous materials.


Assuntos
Ligas/química , Varredura Diferencial de Calorimetria , Cristalografia por Raios X , Temperatura
17.
Nat Commun ; 11(1): 2330, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393818

RESUMO

Recombinant T cell receptors (TCRs) can be used to redirect naïve T cells to eliminate virally infected or cancerous cells; however, they are plagued by low stability and uneven expression. Here, we use molecular modeling to identify mutations in the TCR constant domains (Cα/Cß) that increase the unfolding temperature of Cα/Cß by 20 °C, improve the expression of four separate α/ß TCRs by 3- to 10-fold, and improve the assembly and stability of TCRs with poor intrinsic stability. The stabilizing mutations rescue the expression of TCRs destabilized through variable domain mutation. The improved stability and folding of the TCRs reduces glycosylation, perhaps through conformational stabilization that restricts access to N-linked glycosylation enzymes. The Cα/Cß mutations enables antibody-like expression and assembly of well-behaved bispecific molecules that combine an anti-CD3 antibody with the stabilized TCR. These TCR/CD3 bispecifics can redirect T cells to kill tumor cells with target HLA/peptide on their surfaces in vitro.


Assuntos
Anticorpos Biespecíficos/imunologia , Biologia Computacional/métodos , Receptores de Antígenos de Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Biespecíficos/química , Varredura Diferencial de Calorimetria , Citotoxicidade Imunológica , Imunoglobulina G/metabolismo , Camundongos , Mutação/genética , Polissacarídeos/metabolismo , Desnaturação Proteica , Estabilidade Proteica , Subunidades Proteicas/metabolismo , Receptores de Antígenos de Linfócitos T/química , Proteínas Recombinantes/metabolismo , Solubilidade , Temperatura
18.
Food Chem ; 328: 127053, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464553

RESUMO

Compared with dried noodles, fresh wet noodles (FWNs) have unique flavor and texture characteristics. However, they have a short shelf life due to their high moisture content (approximately 33%). We developed an innovative technique applying cold plasma, which allows the quick removal of some of the moisture to improve their shelf-life. We investigated the effect of cold plasma treatment on the extent of moisture molecule migration and on quality changes in FWNs. A rapid moisture molecule migration occurred due to the synergism between the structure driving force and drying driving force caused by cold plasma. The color of FWNs became whiter and the texture became harder upon plasma treatment. Scanning electron microscopy and differential scanning calorimetry showed that the structural stability of FWNs increased. Moreover, cold plasma treatment had no effect on the secondary structure types of FWNs, while the α-helix and ß-sheet converted to ß-turn and random coil.


Assuntos
Farinha/análise , Gases em Plasma/química , Varredura Diferencial de Calorimetria , Desidratação , Microscopia Eletrônica de Varredura , Paladar
19.
Food Chem ; 326: 126973, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413757

RESUMO

The aim of this study was to substitute part of soybean phospholipid (SPC) with hydrogenated soybean phospholipid (HSPC) in curcumin-loaded liposomes (Cur-LP), in order to further enhance stability and release performances of curcumin. When the SPC/HSPC mass ratio changed from 10:0 to 5:5, vesicle size, encapsulation efficiency and alkali resistance of curcumin increased, although a small decrease in centrifugal stability was observed. Salt stability became worse as more HSPC was used (3:7 and 0:10). Owing storage at 4 °C and 25 °C, Cur-LP at a SPC/HSPC mass ratio of 5:5 performed well considering vesicle size, lipid oxidation and curcumin retention. These vesicles displayed also the best sustained-release performance in simulated digestion, attributed to the tighter lipid packing in membranes as indicated by fluorescence probes, DSC and FTIR. This study can guide the development of a Cur-LP product with improved shelf-life stability by using HSPC.


Assuntos
Curcumina/farmacocinética , Lipossomos/química , Lipossomos/farmacocinética , Fosfolipídeos/química , Varredura Diferencial de Calorimetria , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Hidrogenação , Lecitinas , Soja/química , Espectroscopia de Infravermelho com Transformada de Fourier
20.
AAPS PharmSciTech ; 21(4): 125, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32350635

RESUMO

Sunlight is important to health, but higher exposure to radiation causes early aging of the skin and skin damage that can lead to skin cancers. This study aimed at producing a stable octyl p-methoxycinnamate (OMC)-loaded nanostructured lipid carrier (NLC) sunscreen, which can help in the photoprotective effect. NLC was produced by emulsification-sonication method and these systems were composed of myristyl myristate (MM), caprylic capric triglyceride (CCT), Tween® 80 (TW), and soybean phosphatidylcholine (SP) and characterized by dynamic light scattering (DLS), zeta potential (ZP) measurement, atomic force microscopy (AFM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and in vitro release studies. Pre-formulation studies were performed changing TW concentrations and no differences were found at concentrations of 1.0 and 2.0%. Two selected formulations were designed and showed an average size of 91.5-131.7, polydispersity index > 0.2, and a negative value of ZP. AFM presented a sphere-like morphology and SEM showed ability to form a thin film. DSC exhibited that the incorporation of OMC promoted reduction of enthalpy due to formation of a more amorphous structure. Drug release shows up to 55.74% and 30.57%, and this difference could be related to the presence of SP in this formulation that promoted a more amorphous structure; the release mechanism study indicated Fickian diffusion and relaxation. Sun protection factor (SPF) evaluation was performed using NLC and presented values around 40, considerably higher than those observed in the literature. The developed formulations provide a beneficial alternative to conventional sunscreen formulations.


Assuntos
Cinamatos/síntese química , Portadores de Fármacos/síntese química , Lipídeos/síntese química , Nanoestruturas/química , Fator de Proteção Solar/métodos , Protetores Solares/síntese química , Varredura Diferencial de Calorimetria/métodos , Cinamatos/farmacocinética , Portadores de Fármacos/farmacocinética , Liberação Controlada de Fármacos , Lipídeos/farmacocinética , Microscopia de Força Atômica/métodos , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Protetores Solares/farmacocinética
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