Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.713
Filtrar
1.
J Vis Exp ; (163)2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-33044443

RESUMO

A fascicle of axons is one of the major structural motifs observed in the nervous system. Disruption of axon fascicles could cause developmental and neurodegenerative diseases. Although numerous studies of axons have been conducted, our understanding of formation and dysfunction of axon fascicles is still limited due to the lack of robust three-dimensional in vitro models. Here, we describe a step-by-step protocol for the rapid generation of a motor nerve organoid (MNO) from human induced pluripotent stem (iPS) cells in a microfluidic-based tissue culture chip. First, fabrication of chips used for the method is described. From human iPS cells, a motor neuron spheroid (MNS) is formed. Next, the differentiated MNS is transferred into the chip. Thereafter, axons spontaneously grow out of the spheroid and assemble into a fascicle within a microchannel equipped in the chip, which generates an MNO tissue carrying a bundle of axons extended from the spheroid. For the downstream analysis, MNOs can be taken out of the chip to be fixed for morphological analyses or dissected for biochemical analyses, as well as calcium imaging and multi-electrode array recordings. MNOs generated with this protocol can facilitate drug testing and screening and can contribute to understanding of mechanisms underlying development and diseases of axon fascicles.


Assuntos
Neurônios Motores/fisiologia , Organoides/fisiologia , Animais , Cálcio/metabolismo , Diferenciação Celular , Dimetilpolisiloxanos/química , Eletrodos , Compostos de Epóxi/química , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Microfluídica , Polímeros/química , Técnicas de Cultura de Tecidos
2.
Nat Commun ; 11(1): 4536, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913189

RESUMO

Natural musculoskeletal systems have been widely recognized as an advanced robotic model for designing robust yet flexible microbots. However, the development of artificial musculoskeletal systems at micro-nanoscale currently remains a big challenge, since it requires precise assembly of two or more materials of distinct properties into complex 3D micro/nanostructures. In this study, we report femtosecond laser programmed artificial musculoskeletal systems for prototyping 3D microbots, using relatively stiff SU-8 as the skeleton and pH-responsive protein (bovine serum albumin, BSA) as the smart muscle. To realize the programmable integration of the two materials into a 3D configuration, a successive on-chip two-photon polymerization (TPP) strategy that enables structuring two photosensitive materials sequentially within a predesigned configuration was proposed. As a proof-of-concept, we demonstrate a pH-responsive spider microbot and a 3D smart micro-gripper that enables controllable grabbing and releasing. Our strategy provides a universal protocol for directly printing 3D microbots composed of multiple materials.


Assuntos
Biomimética/métodos , Compostos de Epóxi/efeitos da radiação , Fenômenos Fisiológicos Musculoesqueléticos , Polímeros/efeitos da radiação , Robótica/métodos , Soroalbumina Bovina/efeitos da radiação , Biomimética/instrumentação , Compostos de Epóxi/química , Hidrogéis/química , Hidrogéis/efeitos da radiação , Concentração de Íons de Hidrogênio , Lasers , Polimerização/efeitos da radiação , Polímeros/química , Impressão Tridimensional , Robótica/instrumentação , Soroalbumina Bovina/química
3.
Chemosphere ; 261: 127637, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32717508

RESUMO

Conazole fungicides are currently used pesticides with considerable chronic toxicity and ecotoxicity that are also on EU list for substitution. They enter the soil forming short- or long-term residues. In this study two of their representatives, epoxiconazole (EPC) and tebuconazole (TBC), have been tested with 20 soils from the Czech Republic for their adsorption. Adsorption, by means of Kd coefficients, was compared to "basic" (TOC, pH, clay …) and "advanced" (surface area, minerals ..) soil properties. After doing multivariate analysis of the variables it was apparent that adsorption of both pesticides was highly associated with pH (negatively correlated), and less associated with soil organo-mineral complex (TOC, clay and surface area) and C and N in soil organic matter (OM). Particle sizes or cation exchange capacity (CEC) did not show correlation with adsorption, but showed an association in multidimensional space in factor analysis (FA). Some correlations were revealed between EPC adsorption and soil organic matter parameters. Recalculating Kd to Koc and to Gibb's free energy (ΔG) and its values indicated that the adsorption of EPC and TBC is mainly weak physical adsorption - partitioning. Also, ΔG values gave better correlation with pH(H2O) than Kd. Surface area impacted EPC adsorption. From the several soil minerals, kaolinite showed EPC and TBC adsorption. EPC adsorption was not highly influenced with pH changes compared to TBC. The number and types of H-bonds with molecular geometry govern the sorption, which might crucially affect leachibility in soil, and this may indicate that TBC is more leachable than EPC for the same soil.


Assuntos
Compostos de Epóxi/química , Poluentes do Solo/química , Triazóis/química , Adsorção , Agricultura , Cátions , Argila , República Tcheca , Minerais/química , Tamanho da Partícula , Praguicidas/química , Solo/química
4.
J Oleo Sci ; 69(8): 951-958, 2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32641605

RESUMO

Piperitenone oxide, a major chemical constituent of the essential oil of spearmint, Mentha spicata, induces differentiation in human colon cancer RCM-1 cells. In this study, piperitenone oxide and trans-piperitenone dioxide were prepared as racemic forms by epoxidation of piperitenone. The relative configuration between two epoxides in piperitenone dioxide was determined to be trans by 1H NMR analysis and nuclear Overhauser effect spectroscopy (NOESY) in conjunction with density functional theory (DFT) calculations. Optical resolution of (±)-piperitenone oxide by high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP) afforded both enantiomers with over 98% enantiomeric excess (ee). Evaluation of the differentiation-inducing activity of the synthetic compounds revealed that the epoxide at C-1 and C-6 in piperitenone oxide is important for the activity, and (+)-piperitenone oxide has stronger activity than (-)-piperitenone oxide. The results obtained in this study provide new information on the application of piperitenone oxide and spearmint for differentiation-inducing therapy. Furthermore, natural piperitenone oxide was isolated from M. spicata. The enantiomeric excess of the isolated natural piperitenone oxide was 66% ee. Epoxidation of piperitenone with hydrogen peroxide proceeded in a phosphate buffer under weak basic conditions to give (±)-piperitenone oxide. These results suggest that the nonenzymatic epoxidation of piperitenone, which causes a decrease in the enantiomeric excess of natural piperitenone oxide, is accompanied by an enzymatic epoxidation in the biosynthesis of piperitenone oxide.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/patologia , Compostos de Epóxi/isolamento & purificação , Compostos de Epóxi/farmacologia , Mentha spicata/química , Monoterpenos/isolamento & purificação , Monoterpenos/farmacologia , Óleos Voláteis/síntese química , Óleos Voláteis/isolamento & purificação , Compostos de Epóxi/química , Humanos , Conformação Molecular , Monoterpenos/química , Fitoterapia , Estereoisomerismo , Relação Estrutura-Atividade , Células Tumorais Cultivadas
5.
J Chromatogr A ; 1623: 461154, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505273

RESUMO

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.


Assuntos
Celulose/análogos & derivados , Microesferas , Fenilcarbamatos/química , Polímeros/química , Celulose/química , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Epóxi/química , Metacrilatos/química , Porosidade , Dióxido de Silício/química , Estereoisomerismo , Triazóis/química , Compostos de Vinila/química
6.
Food Chem ; 328: 127147, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32497897

RESUMO

The reduction of the 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) was successfully achieved by the optimization of four processing parameters: phosphoric acid dosage, degumming temperature, bleaching earth dosage, and deodorization temperature by response surface methodology without the need for additional processing steps. The optimized processing conditions were 0.31% phosphoric acid dosage, 50 °C degumming temperature, 3% bleaching earth dosage, and 240 °C deodorization temperature. The optimization resulted in more than 80% and 65% reduction of 3-MCPDE and GE levels, respectively with color and FFA contents maintained in the acceptable range specified by Palm Oil Refiners Association of Malaysia. The optimized refining condition was transferred to macro scale refining units of 1 kg and 3 kg capacities to investigate its successful application during scale-up process.


Assuntos
Indústria de Processamento de Alimentos/métodos , Óleo de Palmeira/química , alfa-Cloridrina/química , Cor , Compostos de Epóxi/química , Ésteres , Qualidade dos Alimentos , Laboratórios , Malásia , Ácidos Fosfóricos/química , Propanóis/química , Temperatura , alfa-Cloridrina/análise
7.
Macromol Rapid Commun ; 41(15): e2000225, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32567153

RESUMO

Long-chain epoxides and specifically alkyl glycidyl ethers represent a class of highly hydrophobic monomers for anionic ring-opening polymerization (AROP), resulting in apolar aliphatic polyethers. In contrast, poly(ethylene glycol) is known for its high solubility in water. The combination of hydrophobic and hydrophilic monomers in block and statistical copolymerization reactions enables the synthesis of amphiphilic polyethers for a wide range of purposes, utilizing micellar interactions in aqueous solutions, e.g., viscosity enhancement of aqueous solutions, formation of supramolecular hydrogels, or for polymeric surfactants. Controlled polymerization of these highly hydrophobic long-chain epoxide monomers via different synthesis strategies, AROP, monomer-activated anionic ring-opening polymerization, catalytic polymerization, or via postmodification, enables precise control of the hydrophilic/lipophilic balance. This renders amphiphilic polymers highly interesting candidates for specialized applications, e.g., as co-surfactants in microemulsion systems. Amphiphilic polyethers based on propylene oxide and ethylene oxide, such as poloxamers are already utilized in many established applications due to the high biocompatibility of the polyether backbone. Long alkyl chain epoxides add an interesting perspective to this area and permit structural tailoring. This review gives an overview of the recent developments regarding the synthesis of amphiphilic polyethers bearing long alkyl chains and their applications.


Assuntos
Compostos de Epóxi/química , Poloxâmero/química , Compostos de Epóxi/síntese química , Óxido de Etileno/síntese química , Óxido de Etileno/química , Interações Hidrofóbicas e Hidrofílicas , Micelas , Poloxâmero/síntese química , Polimerização , Polímeros/síntese química , Polímeros/química , Tensoativos/química
8.
J Food Sci ; 85(7): 2255-2260, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32579733

RESUMO

This study verified the formation profile of esters of 3-monochloropropane-1,2-diol (3-MCPDE), 2-monochloropropane-1,2-diol (2-MCPDE), and glycidol (GE), and evaluated the physicochemical changes (free-fatty acid, acylglycerols, and colour) that occurred during the deodorization of palm oil in different conditions of time (30, 60, 90, and 120 min) and temperature (210, 230, 250, and 270 °C). Levels of 3-MCPD and 2-MCPD esters ranged from 1.91 to 2.70 mg/kg and 0.68 to 1.44 mg/kg, respectively, and were formed at the mildest tested condition (210 °C, 30 min). No correlation was observed between these contaminants and physicochemical changes. GE levels varied from 0.12 to 8.51 mg/kg and showed correlation with color and diacylglycerol content. While the temperature had little influence on the formation of esters of 3-MCPD and 2-MCPD, the content of GE considerably raised above 250 °C.


Assuntos
Compostos de Epóxi/química , Glicerol/análogos & derivados , Óleo de Palmeira/química , alfa-Cloridrina/química , Culinária , Ácidos Graxos não Esterificados/química , Glicerídeos/química , Glicerol/química , Temperatura Alta , Óleos Vegetais/química , Fatores de Tempo
9.
J Chromatogr A ; 1624: 461236, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540076

RESUMO

On-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) used for determining mineral oil aromatic hydrocarbons (MOAH) in foods, particularly in certain oils and fats, may be disturbed by interfering olefins present as natural food components or resulting from raffination of the oils and fats. While some interference can be coped with by disregarding their peaks, others overload GC to the extent of obscuring the MOAH or form humps which need to be distinguished from the hump formed by the MOAH. In the latter cases, it is necessary to remove these interferences prior to HPLC-GC analysis. So far, epoxidation of the olefins to increase their retention time beyond that of the MOAH in HPLC is the best method available, though imperfect by causing some loss of MOAH and sometimes incomplete removal of the interference. Two methods are re-evaluated; preference is given to a slightly modified version of that proposed by Nestola and Schmidt. The performances are comparable: the losses of MOAH are similar and with both methods not all interfering olefins may be removed from refined edible oils. However, the Nestola/Schmidt method has practical advantages, the main ones being that no cooling is necessary and no solvent needs to be evaporated, which facilitates automation. Potential residual interferences must be recognized and subtracted, which can be by the characteristics of the hump they form in HPLC-GC-FID, by GCxGC-FID or by GCxGC-MS using characteristic mass fragments.


Assuntos
Compostos de Epóxi/química , Contaminação de Alimentos/análise , Alimentos , Hidrocarbonetos Aromáticos/análise , Óleo Mineral/análise , Alcenos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Etanol/química , Azeite de Oliva/análise , Sistemas On-Line
10.
J Chromatogr A ; 1622: 461097, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32381302

RESUMO

In this study, polymeric monoliths with gold nanoparticles (AuNP@monolith) were investigated as microcartridges for the analysis of protein biomarkers by on-line solid-phase extraction capillary electrophoresis-mass spectrometry (SPE-CE-MS). "Plug-and-play" microcartridges (7 mm) were prepared from a glycidyl methacrylate (GMA)-based monolithic capillary column (5 cm x 250 µm i.d.), which was modified with ammonia and subsequently functionalized with gold nanoparticles (AuNPs). The performance of these novel microcartridges was evaluated with human transthyretin (TTR), which is a protein related to different types of familial amyloidotic polyneuropathies (FAP). Protein retention depended on the isoelectric point of the protein (TTR pI~5.4) and elution was achieved with a basic phosphate solution. Under the optimized conditions, limits of detection (LODs) for TTR by AuNP@monolith-SPE-CE-MS were 50 times lower than by CE-MS (5 vs 250 mg•L-1, with an ion trap (IT) mass spectrometer). The sensitivity enhancement was similar compared to SPE-CE-MS using immunoaffinity (IA) microcartridges with intact antibodies against TTR. Linearity, repeatability in migration times and peak areas, reusability, reproducibility and application to serum samples were also evaluated.


Assuntos
Biomarcadores , Eletroforese Capilar , Ouro , Espectrometria de Massas , Nanopartículas Metálicas , Pré-Albumina , Extração em Fase Sólida , Biomarcadores/análise , Compostos de Epóxi/química , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Metacrilatos/química , Polímeros/química , Pré-Albumina/análise , Reprodutibilidade dos Testes
11.
Biochem Pharmacol ; 178: 114048, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32446889

RESUMO

Epoxy-tiglianes are a novel class of diterpene esters. The prototype epoxy-tigliane, EBC-46 (tigilanol tiglate), possesses potent anti-cancer properties and is currently in clinical development as a local treatment for human and veterinary cutaneous tumors. EBC-46 rapidly destroys treated tumors and consistently promotes wound re-epithelialization at sites of tumor destruction. However, the mechanisms underlying these keratinocyte wound healing responses are not completely understood. Here, we investigated the effects of EBC-46 and an analogue (EBC-211) at 1.51 nM-151 µM concentrations, on wound healing responses in immortalized human skin keratinocytes (HaCaTs). Both EBC-46 and EBC-211 (1.51 nM-15.1 µM) accelerated G0/G1-S and S-G2/M cell cycle transitions and HaCaT proliferation. EBC-46 (1.51-151 nM) and EBC-211 (1.51 nM-15.1 µM) further induced significant HaCaT migration and scratch wound repopulation. Stimulated migration/wound repopulation responses were even induced by EBC-46 (1.51 nM) and EBC-211 (1.51-151 nM) with proliferation inhibitor, mitomycin C (1 µM), suggesting that epoxy-tiglianes can promote migration and wound repopulation independently of proliferation. Expression profiling analyses showed that epoxy-tiglianes modulated keratin, DNA synthesis/replication, cell cycle/proliferation, motility/migration, differentiation, matrix metalloproteinase (MMP) and cytokine/chemokine gene expression, to facilitate enhanced responses. Although epoxy-tiglianes down-regulated established cytokine and chemokine agonists of keratinocyte proliferation and migration, enhanced HaCaT responses were demonstrated to be mediated via protein kinase C (PKC) phosphorylation and significantly abrogated by pan-PKC inhibitor, bisindolylmaleimide-1 (BIM-1, 1 µM). By identifying how epoxy-tiglianes stimulate keratinocyte healing responses and re-epithelialization in treated skin, our findings support the further development of this class of small molecules as potential therapeutics for other clinical situations associated with impaired re-epithelialization, such as non-healing skin wounds.


Assuntos
Compostos de Epóxi/farmacologia , Queratinócitos/efeitos dos fármacos , Forbóis/farmacologia , Proteína Quinase C , Reepitelização/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Linhagem Celular Transformada , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Compostos de Epóxi/química , Humanos , Queratinócitos/enzimologia , Forbóis/química , Proteína Quinase C/metabolismo , Reepitelização/fisiologia , Cicatrização/fisiologia
12.
Chemistry ; 26(36): 8035-8044, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32259333

RESUMO

Disabling the bacterial capacity to cause infection is an innovative approach that has attracted significant attention to fight against superbugs. A relevant target for anti-virulence drug discovery is the type I dehydroquinase (DHQ1) enzyme. It was shown that the 2-hydroxyethylammonium derivative 3 has in vitro activity since it causes the covalent modification of the catalytic lysine residue of DHQ1. As this compound does not bear reactive electrophilic centers, how the chemical modification occurs is intriguing. We report here an integrated approach, which involves biochemical studies, X-ray crystallography and computational studies on the reaction path using combined quantum mechanics/molecular mechanics Umbrella Sampling Molecular Dynamics, that evidences that DHQ1 catalyzes its self-immolation by transforming the unreactive 2-hydroxyethylammonium group in 3 into an epoxide that triggers the lysine covalent modification. This finding might open opportunities for the design of lysine-targeted irreversible inhibitors bearing a 2-hydroxyethylammonium moiety as an epoxide proform, which to our knowledge has not been reported previously.


Assuntos
Bactérias/química , Inibidores Enzimáticos/química , Compostos de Epóxi/química , Hidroliases/química , Bactérias/metabolismo , Catálise , Descoberta de Drogas , Hidroliases/metabolismo , Lisina , Simulação de Dinâmica Molecular
13.
J Oleo Sci ; 69(5): 449-453, 2020 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-32238621

RESUMO

A poly(ethylene oxide) (PEO)-poly(propylene oxide) (PPO) alternating multiblock (AMB) copolymer with various molecular weights was prepared via precipitation fractionation from an acetone/n-hexane mixture. The cloud point (Tc) of the aqueous solution of PEO-PPO AMB copolymer decreased as the number-average molecular weight of the sample increased. This phenomenon is generally observed for certain homopolymer systems having a lower critical solution temperature, such as PEO/water and poly(N,N-diethylacrylamide)/water systems. The relationship between the Tc of the solutions and the number of monomer units of the AMB copolymer suggests that the Shultz-Flory theory is applicable to this system.


Assuntos
Compostos de Epóxi/química , Peso Molecular , Polietilenoglicóis/química , Polímeros/química , Água , Acetona/química , Precipitação Fracionada , Hexanos/química , Soluções , Temperatura
14.
Talanta ; 214: 120860, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32278420

RESUMO

A glycidyl methacrylate-based monolith was modified with imidazolium-based ionic liquid (IL) to be used as stationary phase for solid-phase extraction (SPE). The host monolithic support was prepared by in-situ UV polymerization in spin column format. Two approaches were developed to incorporate the IL into the polymeric monolithic matrix: generation of IL onto the surface monolith, and copolymerization by addition of the IL to the polymerization mixture, which gave the best results. The resulting sorbent materials were morphologically characterized and used for the isolation of five ß-blockers from human urine samples. All SPE steps were accomplished by centrifugation, which reduces significantly costs and time in sample treatment. Under optimal conditions, ß-blockers were quantitatively retained in the modified monolith at pH 12, and desorbed with a water-methanol mixture, to be subsequently determined via HPLC with UV detection. The limits of detection ranged between 1.4 and 40 µg L-1, and the reproducibility among extraction units (expressed as relative standard deviation) was below 8.2%. The novel phase was successfully applied to the extraction of propranolol in urine samples with recoveries above 90%.


Assuntos
Antagonistas Adrenérgicos beta/isolamento & purificação , Compostos Alílicos/química , Compostos de Epóxi/química , Imidazóis/química , Metacrilatos/química , Polímeros/química , Extração em Fase Sólida , Antagonistas Adrenérgicos beta/química , Antagonistas Adrenérgicos beta/urina , Humanos , Tamanho da Partícula , Propriedades de Superfície
15.
Talanta ; 215: 120909, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32312453

RESUMO

A novel impedimetric immunosensor based on a conjugated polypyrrole polymer containing epoxy active side groups (PPCE) modified indium tin oxide (ITO) electrode was developed for detection of interleukin 6 (IL 6), a prostate cancer biomarker. IL 6 receptor was used as a biorecognition molecule and successfully immobilized by covalent linkage on the modified ITO electrode. Pyrrole monomer containing epoxy active side group was electropolymerized on the disposable ITO electrode for the first time and used as an immobilization matrix for IL 6 receptor. The designed biosensor fabrication stages were analyzed by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. For the quantification of IL 6 biomarker, EIS technique was utilized. In addition, the specific immuno-interaction between IL 6 receptor and IL 6 antigen was followed by single frequency impedance (SFI) technique. The resulting biosensor exhibited a linear calibration curve over the 0.02-16 pg/mL IL 6 concentration range, a limit of detection (LOD) of 6.0 fg/mL and a good selectivity against other interference biomarkers. Additionally, an excellent reproducibility, a long storage stability and an acceptable repeatability were found. The proposed impedimetric immunosensor was applied successfully to quantify for the IL 6 biomarker in human serum and it displayed a remarkable response in the real sample analysis with serum samples. In comparison with the commercial ELISA kit, the immunosensor provided a lower LOD and a lower analysis cost. In conclusion, the proposed impedimetric immunosensor could be clinically useful in the early diagnosis of the prostate cancer by detection of the serum samples after only simple dilution with phosphate buffer.


Assuntos
Biomarcadores Tumorais/análise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Compostos de Epóxi/química , Interleucina-6/análise , Polímeros/química , Pirróis/química , Compostos de Estanho/química , Eletrodos , Compostos de Epóxi/síntese química , Humanos , Tamanho da Partícula , Polímeros/síntese química , Pirróis/síntese química , Propriedades de Superfície
16.
ACS Appl Mater Interfaces ; 12(12): 14443-14458, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32134620

RESUMO

The study describes the curing and thermal behavior of a new castor oil maleic anhydride adduct/epoxy oils/5-Bromosalicylic acid coatings and their composites with wood. The epoxidized oils were flax and hemp. The kinetic parameters of the curing and thermal degradation processes were calculated. The resistance of the coated wood surfaces against Cladosporium cladosporioides, Aspergillus brasiliensis, and Penicillium chrysogenum was tested. Color changes, FT-IR and SEM were conducted before and after fungal attack. The decay resistance and color change of raw wood and wood treated samples against fungi was tested. Based on the color changes and according to ASTM D 2017, the decay resistance rating for covered samples was considered as "highly resistant". Chemical resistance and coating performance tests were also undertaken. The obtained results recommend the described materials for applications in wood protective coatings.


Assuntos
Óleo de Rícino/química , Materiais Revestidos Biocompatíveis/farmacologia , Óleos Vegetais/farmacologia , Madeira/química , Aspergillus/efeitos dos fármacos , Óleo de Rícino/farmacologia , Cladosporium/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Compostos de Epóxi/química , Compostos de Epóxi/farmacologia , Resinas Epóxi/química , Linho/química , Fungos/efeitos dos fármacos , Anidridos Maleicos/química , Anidridos Maleicos/farmacologia , Óleos Vegetais/química , Salicilatos/química , Salicilatos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Madeira/microbiologia
17.
Molecules ; 25(6)2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32168826

RESUMO

Biological systems usually respond differently to enantiomers of a chiral molecule due to the inherent chirality of the active receptor sites of enzymes in nature [...].


Assuntos
Técnicas de Química Sintética , Azepinas/química , Álcoois Benzílicos/química , Butiratos/química , Catálise , Compostos de Epóxi/química , Humanos , Hidrocarbonetos Fluorados/química , Propanóis/química , Compostos de Rutênio/química , Bases de Schiff/química , Estereoisomerismo
18.
Chirality ; 32(5): 579-587, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32126590

RESUMO

Two new carotenoids, sapotexanthin 5,6-epoxide and sapotexanthin 5,8-epoxide, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Sapotexanthin 5,6-epoxide was also prepared by partial synthesis via epoxidation of sapotexanthin, and the (5R,6S) and (5S,6R) stereoisomers were identified by high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) analysis. Spectroscopic data of the natural and semisynthetic derivatives obtained by acid-catalyzed rearrangement of cryptocapsin 5,8-epoxide stereoisomers were compared for structural elucidation.


Assuntos
Carotenoides/análise , Carotenoides/isolamento & purificação , Compostos de Epóxi/química , Pouteria/química , Carotenoides/química , Estereoisomerismo
19.
Org Biomol Chem ; 18(12): 2346-2359, 2020 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-32163082

RESUMO

Total synthesis of marine secondary metabolite nafuredin B has been achieved for the first time using a convergent strategy. Sharpless epoxidation followed by acid catalyzed epoxide opening were adopted to install the tetrasubstituted hydroxy center, whereas the iterative Julia-Kocienski olefination, Wittig olefination and HWE olefination afforded the olefin bonds. Ring closing metathesis in the presence of a free tetrasubstituted hydroxy group provided the unsaturated δ-lactone moiety. This synthetic study provided unambiguous structural confirmation of the isolated nafuredin B.


Assuntos
Pironas/síntese química , Alcenos/química , Compostos de Epóxi/química , Lactonas/química , Estrutura Molecular
20.
Inorg Chem ; 59(7): 5231-5239, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32212684

RESUMO

With the aid of a pyridyl tetracarboxylate ligand, 2,5-bis(2',5'-dicarboxylphenyl)pyridine (H4L), two indium-organic frameworks, [In2(L)(OH)2]·2DMF·2H2O (1) and [Me2NH2][In(L)]·2.5NMF·4H2O (2), with (6,8)- and (4,4)-connected nets have been constructed in different solvent systems. Both 1 and 2 exhibit high thermal and chemical stability. Gas sorption behavior of 1 and 2 for N2, C2H2, C2H4, CO2, and CH4 indicate excellent separation selectivities of C2Hx/CH4 and CO2/CH4. Furthermore, 1 possesses a high density of Brønsted sites and shows efficient catalytic conversion for CO2 cycloaddition with epoxides. Meanwhile, luminescence investigations reveal that 2 can detect nitrofurazone efficiently.


Assuntos
Antibacterianos/análise , Dióxido de Carbono/química , Estruturas Metalorgânicas/química , Adsorção , Catálise , Reação de Cicloadição , Compostos de Epóxi/química , Índio/química , Ligantes , Porosidade , Piridinas/química , Espectrometria de Fluorescência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA