Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.056
Filtrar
1.
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
2.
Life Sci ; 256: 117975, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32565251

RESUMO

Our goal is to understand how loss of circulating estrogens and estrogen replacement affect brain physiology and function, particularly in brain regions involved in cognitive processes. We recently conducted a large metabolomics study characterizing the effects of rodent models of menopause and treatment with estrogen receptor (ER) agonists on neurochemical targets in hippocampus, frontal cortex, and striatum. Here we characterize effects on levels of several key enzymes involved in glucose utilization and energy production, specifically phosphofructokinase, glyceraldehyde 3-phosphate dehydrogenase, and pyruvate dehydrogenase. We also evaluated effects on levels of ß-actin and α-tubulin, choline acetyltransferase (ChAT) activity, and levels of ATP citrate lyase. All experiments were conducted in young adult rats. Experiment 1 compared the effects of ovariectomy (OVX), a model of surgical menopause, and 4-vinylcyclohexene diepoxide (VCD)-treatments, a model of transitional menopause, with tissues collected at proestrus and at diestrus. Experiment 2 used a separate cohort of rats to evaluate the same targets in OVX and VCD-treated rats treated with estradiol or with selective ER agonists. Differences in the expression of metabolic enzymes between cycling animals and models of surgical and transitional menopause were detected. These differences were model-, region- and time- dependent, and were modulated by selective ER agonists. Collectively, the findings demonstrate that loss of ovarian function and ER agonist treatments have differing effects in OVX vs. VCD-treated rats. Differences may help to explain differences in the effects of estrogen treatments on brain function and cognition in women who have experienced surgical vs. transitional menopause.


Assuntos
Acetilcoenzima A/metabolismo , Encéfalo/metabolismo , Colina O-Acetiltransferase/metabolismo , Estrogênios/farmacologia , Menopausa/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Cicloexenos/toxicidade , Estradiol/sangue , Feminino , Menopausa/efeitos dos fármacos , Ovariectomia/efeitos adversos , Ratos , Ratos Sprague-Dawley , Compostos de Vinila/toxicidade
3.
J Chromatogr A ; 1623: 461159, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505275

RESUMO

In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step 2,2'-azobis(2-methylpropionitrile) (AIBN) as the initiator, followed by a polymerization step to generate the monolith; (ii) for glass-reinforced PP (GPP) a silanization step or wall modification preceded the polymerization reaction. The success of wall attachment and the morphology of the monoliths were studied using scanning electron microscopy (SEM), and the permeability of the columns was studied in flow experiments. In both types of housings polystyrene-divinylbenzene (PS-DVB) monoliths were successfully fabricated with good wall attachment. Within the glass-reinforced polypropylene (GPP) printed housing, SEM pictures showed a radially homogenous monolithic structure. The feasibility of performing liquid-chromatographic separations in 3D-printed channels was demonstrated.


Assuntos
Cromatografia de Fase Reversa/métodos , Polipropilenos/química , Impressão Tridimensional , Microscopia Eletrônica de Varredura , Polimerização , Polímeros/química , Poliestirenos/química , Porosidade , Compostos de Vinila/química
4.
J Chromatogr A ; 1623: 461175, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505279

RESUMO

An ionic liquid hybrid zwitterionic polymer capillary microextraction (CME) column was prepared for the biomimetic enrichment of glycopeptides by one-step copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 1-butyl-3-vinylimidazolium bromide, in the presence of crosslinker trimethylolpropane trimethacrylate (TMA). The resultant monolith was characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy and pore size distribution measurement. Due to the incorporation of zwitterionic MPC owning a unique biomimic structure (i.e. hydrophilic cation/anion and hydrophobic long-alkyl chain), the monolithic column has large pore size and good biocompatibility, exhibiting high extraction efficiency, permeability and fast mass transfer to targets. Besides, the use of ionic liquids (ILs) as co-monomer in the polymerization endows the monolith with enhanced mechanical stability, uniformity and multiple interactions. The prepared column was successfully applied in CME coupled to capillary electrochromatography (CEC) for the efficient enrichment and separation of glycopeptide antibiotics in foodstuff. The method demonstrated a wide linear range (50.0-18000.0 µg L-1), low detection limits (5.0-10.0 µg L-1, S/N = 3) and satisfied recoveries (76.0-109.7%). This work shows the advantage of fine-tuning biomimetic monoliths in application-specific CME-CEC.


Assuntos
Antibacterianos/análise , Eletrocromatografia Capilar/métodos , Glicopeptídeos/análise , Líquidos Iônicos/química , Antibacterianos/isolamento & purificação , Materiais Biomiméticos , Fracionamento Químico , Análise de Alimentos/métodos , Glicopeptídeos/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Imidazóis/química , Metacrilatos/química , Microscopia Eletrônica de Varredura , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Polimerização , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Vinila/química
5.
Am J Physiol Heart Circ Physiol ; 318(6): H1461-H1473, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32383991

RESUMO

There is a sharp rise in cardiovascular disease (CVD) risk and progression with the onset of menopause. The 4-vinylcyclohexene diepoxide (VCD) model of menopause recapitulates the natural, physiological transition through perimenopause to menopause. We hypothesized that menopausal female mice were more susceptible to CVD than pre- or perimenopausal females. Female mice were treated with VCD or vehicle for 20 consecutive days. Premenopausal, perimenopausal, and menopausal mice were administered angiotensin II (ANG II) or subjected to ischemia-reperfusion (I/R). Menopausal females were more susceptible to pathological ANG II-induced cardiac remodeling and cardiac injury from a myocardial infarction (MI), while perimenopausal, like premenopausal, females remained protected. Specifically, ANG II significantly elevated diastolic (130.9 ± 6.0 vs. 114.7 ± 6.2 mmHg) and systolic (156.9 ± 4.8 vs. 141.7 ± 5.0 mmHg) blood pressure and normalized cardiac mass (15.9 ± 1.0 vs. 7.7 ± 1.5%) to a greater extent in menopausal females compared with controls, whereas perimenopausal females demonstrated a similar elevation of diastolic (93.7 ± 2.9 vs. 100.5 ± 4.1 mmHg) and systolic (155.9 ± 7.3 vs. 152.3 ± 6.5 mmHg) blood pressure and normalized cardiac mass (8.3 ± 2.1 vs. 7.5 ± 1.4%) compared with controls. Similarly, menopausal females demonstrated a threefold increase in fibrosis measured by Picrosirus red staining. Finally, hearts of menopausal females (41 ± 5%) showed larger infarct sizes following I/R injury than perimenopausal (18.0 ± 5.6%) and premenopausal (16.2 ± 3.3, 20.1 ± 4.8%) groups. Using the VCD model of menopause, we provide evidence that menopausal females were more susceptible to pathological cardiac remodeling. We suggest that the VCD model of menopause may be critical to better elucidate cellular and molecular mechanisms underlying the transition to CVD susceptibility in menopausal women.NEW & NOTEWORTHY Before menopause, women are protected against cardiovascular disease (CVD) compared with age-matched men; this protection is gradually lost after menopause. We present the first evidence that demonstrates menopausal females are more susceptible to pathological cardiac remodeling while perimenopausal and cycling females are not. The VCD model permits appropriate examination of how increased susceptibility to the pathological process of cardiac remodeling accelerates from pre- to perimenopause to menopause.


Assuntos
Remodelamento Atrial/fisiologia , Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/fisiopatologia , Cicloexenos , Menopausa/fisiologia , Compostos de Vinila , Angiotensina II , Animais , Doenças Cardiovasculares/induzido quimicamente , Feminino , Camundongos , Modelos Animais
6.
Plant Foods Hum Nutr ; 75(3): 355-361, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32388808

RESUMO

Organosulfur compounds (OSCs) of garlic have various health benefits including anti-hypertensive effect. It has been described that volatile OSCs uptake occurs into a moderate extent. Among the bioavailable OSCs present in garlic, 2-vinyl-4H-1,3-dithiin (2VD) is a main component in garlic macerated oil and stir-fried garlic but has been poorly investigated compared with others OSCs, such allyl mercaptan (AM) and S-allyl cysteine (SAC). The aim of this study was to evaluate the effects of 2VD on vascular smooth muscle cells (VSMCs) isolated from spontaneous hypertensive rats (SHR) and compare them with those produced by AM and SAC. Cell viability and proliferation were measured using tetrazolium dye MTT assay and flow cytometry. Cell migration was evaluated by scrape-wound migration assay. OSCs anti-oxidative capacity was determined by measuring reactive oxygen species (ROS) generation, and total antioxidant status (TAS). Non-toxic plasmatic concentrations (10 µg L-1) of 2VD and AM inhibited VSMCs proliferation stimulated with 5% fetal bovine serum and impaired cell migration. In further flow cytometry analysis 2VD treatment resulted in a partial cell cycle arrest at G2 phase. The OSCs tested were able to prevent ROS increase after angiotensin II stimulation and surprisingly 2VD induced higher total antioxidant status compared with AM and SAC. Our results showed that 2VD produces equivalent or superior beneficial effects on VSMCs to those reported for other bioavailable compounds of garlic. This preliminary evidence suggests that 2VD intake could also exert important protective effects against arterial remodeling in hypertension.


Assuntos
Alho , Animais , Antioxidantes , Proliferação de Células , Compostos Heterocíclicos , Músculo Liso Vascular , Estresse Oxidativo , Ratos , Compostos de Enxofre , Compostos de Vinila
7.
Proc Natl Acad Sci U S A ; 117(14): 7792-7798, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32209662

RESUMO

A significant fraction of the glycerophospholipids in the human body is composed of plasmalogens, particularly in the brain, cardiac, and immune cell membranes. A decline in these lipids has been observed in such diseases as Alzheimer's and chronic obstructive pulmonary disease. Plasmalogens contain a characteristic 1-O-alk-1'-enyl ether (vinyl ether) double bond that confers special biophysical, biochemical, and chemical properties to these lipids. However, the genetics of their biosynthesis is not fully understood, since no gene has been identified that encodes plasmanylethanolamine desaturase (E.C. 1.14.99.19), the enzyme introducing the crucial alk-1'-enyl ether double bond. The present work identifies this gene as transmembrane protein 189 (TMEM189). Inactivation of the TMEM189 gene in human HAP1 cells led to a total loss of plasmanylethanolamine desaturase activity, strongly decreased plasmalogen levels, and accumulation of plasmanylethanolamine substrates and resulted in an inability of these cells to form labeled plasmalogens from labeled alkylglycerols. Transient expression of TMEM189 protein, but not of other selected desaturases, recovered this deficit. TMEM189 proteins contain a conserved protein motif (pfam10520) with eight conserved histidines that is shared by an alternative type of plant desaturase but not by other mammalian proteins. Each of these histidines is essential for plasmanylethanolamine desaturase activity. Mice homozygous for an inactivated Tmem189 gene lacked plasmanylethanolamine desaturase activity and had dramatically lowered plasmalogen levels in their tissues. These results assign the TMEM189 gene to plasmanylethanolamine desaturase and suggest that the previously characterized phenotype of Tmem189-deficient mice may be caused by a lack of plasmalogens.


Assuntos
Lipídeos/genética , Oxirredutases/genética , Plasmalogênios/genética , Enzimas de Conjugação de Ubiquitina/genética , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Linhagem Celular , Humanos , Camundongos , Oxirredução , Oxirredutases/metabolismo , Fenótipo , Plasmalogênios/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Compostos de Vinila/metabolismo
8.
J Med Chem ; 63(6): 3298-3316, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32125159

RESUMO

Cruzain, an essential cysteine protease of the parasitic protozoan, Trypanosoma cruzi, is an important drug target for Chagas disease. We describe here a new series of reversible but time-dependent inhibitors of cruzain, composed of a dipeptide scaffold appended to vinyl heterocycles meant to provide replacements for the irreversible reactive "warheads" of vinyl sulfone inactivators of cruzain. Peptidomimetic vinyl heterocyclic inhibitors (PVHIs) containing Cbz-Phe-Phe/homoPhe scaffolds with vinyl-2-pyrimidine, vinyl-2-pyridine, and vinyl-2-(N-methyl)-pyridine groups conferred reversible, time-dependent inhibition of cruzain (Ki* = 0.1-0.4 µM). These cruzain inhibitors exhibited moderate to excellent selectivity versus human cathepsins B, L, and S and showed no apparent toxicity to human cells but were effective in cell cultures of Trypanosoma brucei brucei (EC50 = 1-15 µM) and eliminated T. cruzi in infected murine cardiomyoblasts (EC50 = 5-8 µM). PVHIs represent a new class of cruzain inhibitors that could progress to viable candidate compounds to treat Chagas disease and human sleeping sickness.


Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Peptidomiméticos/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Compostos de Vinila/farmacologia , Animais , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/metabolismo , Desenho de Fármacos , Ensaios Enzimáticos , Humanos , Cinética , Camundongos , Simulação de Acoplamento Molecular , Mioblastos Cardíacos/efeitos dos fármacos , Peptidomiméticos/síntese química , Peptidomiméticos/metabolismo , Ligação Proteica , Proteínas de Protozoários/metabolismo , Piridinas/síntese química , Piridinas/metabolismo , Piridinas/farmacologia , Pirimidinas/síntese química , Pirimidinas/metabolismo , Pirimidinas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/metabolismo , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Compostos de Vinila/síntese química , Compostos de Vinila/metabolismo
9.
Pharm Res ; 37(4): 70, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32185516

RESUMO

PURPOSE: While including amorphous solid dispersion (ASD) in tablet formulations is increasingly common, tablets containing high ASD loading are associated with slow disintegration, which presents a challenge to control pill burden for less potent compounds. METHODS: We use a model ASD, composed of a hydrophobic drug with copovidone and a non-ionic surfactant, to explore formulation options that can prevent slow disintegration. RESULTS: In addition to the ASD loading, the pH of the disintegration medium and the inclusion of inorganic salts in the tablet also have an impact on the tablet disintegration time. Certain kosmotropic salts, when added in the formulation, can significantly accelerate tablet disintegration, though the rank order in their effectiveness does not exactly follow the Hofmeister series at pH 1.8. The particle size and dissolution rate of the salt can contribute to its overall effectiveness. CONCLUSION: We provided a mechanistic explanation of the disintegration process: fast-dissolving kosmotropic salt results in a concentrated salt solution inside the restrained tablet matrix, thus inhibiting the dissolution of copovidone and preventing polymer gelling which is the main cause leading the slow disintegration. The outcome of this study has enabled the design of a higher ASD loading platform formulation for copovidone based ASD. Graphical Abstract MicroCT aids the mechanistic understanding of the role of inorganic salt in the tablet disintegration of amorphous solid dispersion based formulation.


Assuntos
Pirrolidinas/química , Sais/química , Comprimidos/química , Compostos de Vinila/química , Química Farmacêutica , Excipientes/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Concentração Osmolar , Tamanho da Partícula , Solubilidade
10.
Environ Sci Technol ; 54(7): 3909-3919, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32108486

RESUMO

To clarify how coexisting atmospheric pollutants affect secondary organic aerosol (SOA) formation, we investigated the effects of mixed gaseous pollutants (CO and SO2) and mixed organic-inorganic (MOI) particles on SOA formation during n-butyl vinyl ether (BVE) ozonolysis. Higher CO levels (90 ppm) were found to significantly change the chemical composition of SOA (prompting monomers while reducing oligomer formation) without causing much change in the overall SOA mass. Based on the positive matrix factorization (PMF) analysis, heterogeneous chemical conversions between preformed and newly formed SOA were the major pathways of SOA formation in the presence of MOI particles. Furthermore, MOI particles had an enhancing effect on SOA formation at 1% relative humidity (RH) but a negligible effect at higher RH (10 and 55%). The enhancing effect was attributed to the formation of multifunctional products resulting from high functionalization of preformed and newly formed SOA. The negligible effect observed was ascribed to the cleavage of unstable oligomers as a result of the reversible oligomerization of preformed and newly formed SOA. Even so, MOI particles could still affect the composition of newly formed SOA. These results highlight the need to account for the significant effect of mixed gaseous and particulate pollutants on both SOA constituents and their evolution.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , Ozônio , Aerossóis , Éteres , Compostos de Vinila
11.
Macromol Rapid Commun ; 41(4): e1900550, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894629

RESUMO

Thermo-responsive block copolymers are of great interest in biomedical and nanotechnological fields. These polymers achieve a versatile and complex responsiveness through a sophisticated and intricate combination of different thermo-responsive blocks. While their utility is clear, the fundamental design principles of such vinyl polymers are not yet thoroughly understood. Herein, a precise synthesis of sequence-controlled amino-acid-derived vinyl polymers and their unique thermal response in water are reported. Seven distinct block (random) copolymers that contain two kinds of amino acid blocks (poly(N-acryloyl alanine(A)- or glycine(G)-methyl ester)) with the same total chain length (degree of polymerization [DP] ≈30) and chemical composition (A/G ≈1), but with systematic variations in the block sequence and length, with an accuracy target of DP ± 1, are prepared. By specifying the primary structure, the thermal responses including transition temperature, thermo-sensitivity, and microenvironment in the dehydrated state can be finely tuned. These findings offer new directions in the design of structurally and functionally diverse thermo-responsive vinyl polymers.


Assuntos
Polímeros/química , Polímeros/síntese química , Compostos de Vinila/química , Alanina/análogos & derivados , Alanina/química , Aminoácidos/química , Glicina/análogos & derivados , Glicina/química , Polimerização , Temperatura , Água
12.
Nat Commun ; 11(1): 446, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974383

RESUMO

Afterglow luminescent probes with high signal-to-background ratio show promise for in vivo imaging; however, such probes that can be selectively delivered into target sites and switch on afterglow luminescence remain limited. We optimize an organic electrochromic material and integrate it into near-infrared (NIR) photosensitizer (silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) and (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) containing nanoparticles, developing an H2S-activatable NIR afterglow probe (F12+-ANP). F12+-ANP displays a fast reaction rate (1563 ± 141 M-1 s-1) and large afterglow turn-on ratio (~122-fold) toward H2S, enabling high-sensitivity and -specificity measurement of H2S concentration in bloods from healthy persons, hepatic or colorectal cancer patients. We further construct a hepatic-tumor-targeting and H2S-activatable afterglow probe (F12+-ANP-Gal) for noninvasive, real-time imaging of tiny subcutaneous HepG2 tumors (<3 mm in diameter) and orthotopic liver tumors in mice. Strikingly, F12+-ANP-Gal accurately delineates tumor margins in excised hepatic cancer specimens, which may facilitate intraoperative guidance of hepatic cancer surgery.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Sulfeto de Hidrogênio/análise , Neoplasias Hepáticas/diagnóstico por imagem , Substâncias Luminescentes/química , Imagem Molecular/métodos , Animais , Neoplasias Colorretais/sangue , Cistationina beta-Sintase/análise , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/análise , Cistationina gama-Liase/metabolismo , Células Hep G2 , Humanos , Sulfeto de Hidrogênio/sangue , Sulfeto de Hidrogênio/química , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas Experimentais/diagnóstico por imagem , Substâncias Luminescentes/síntese química , Camundongos Endogâmicos BALB C , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Polímeros/química , Compostos de Vinila/química , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Appl Biochem Biotechnol ; 190(2): 423-436, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31376051

RESUMO

Lignocellulosic hydrolysate contains complex nonsugar compounds and undegraded sugars in the process of preparing platform compound levulinic acid (LA) and furfural by one-step dilute-acid hydrolysis. For efficiently and comprehensively utilizing the hydrolysate, a series of polar modified resins were synthesized for adsorption and separation of the sugarcane bagasse hydrolysate to obtain platform compounds and fermentable hydrolysate simultaneously. The adsorption capacities of LA and furfural were optimized to 85.32 mg/g and 33.55 mg/g on polar modified resin prepared with 80 wt% glycidyl methacrylate (GMA -80), which was much higher than nonpolar resin (4.16 mg/g and 16.14 mg/g). GMA-80 obtained the best comprehensive adsorption property, whose desorption rates were 99.90% and 89.86% for LA and furfural, respectively, and its regeneration performance was also excellent, indicating that the resin is a potential adsorbent and expected to be used in the separation and purification of the lignocellulosic hydrolysate.


Assuntos
Celulose/química , Polímeros/química , Saccharum/química , Estireno/química , Compostos de Vinila/química , Adsorção , Hidrólise
14.
J Chromatogr A ; 1613: 460676, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31727351

RESUMO

Due to the trace levels of polycyclic aromatic hydrocarbons (PAHs) in soil and the complexity of soil matrices, effective sample pretreatment methods are of great significance to obtain accurate analytical results. In this paper, polydopamine (PDA) encapsulated Fe3O4 particles were used as seeds for in situ polymerization of divinylbenzene (DVB) to derive magnetic hybrid material Fe3O4@PDA@PDVB. Coupled with pressurized liquid extraction, Fe3O4@PDA@PDVB was investigated as a selective adsorbent for the extraction and cleanup of PAHs in soil. The prepared magnetic material was characterized and demonstrated to possess strong hydrophobicity and superparamagnetism. Under optimal conditions, Fe3O4@PDA@PDVB can effectively extract 15 PAHs from a 30% methanol solution within 2 min, and it is more selective for PAHs than for n-alkane in soil extracts. The matrix effect significantly decreased after extraction by the prepared material, which showed superiority to a silica gel column method (EPA 3630C Method). The developed method was linear (5-1000 ng g-1) with coefficient of determination (R2) ranging from 0.9986-0.9998, and the limits of detection were 0.13-0.54 ng g-1. Additionally, repetitive experiments indicated that the prepared material was reproducible and reusable with relative standard deviations below 8.4% and 8.6%, respectively. Finally, the new method was successfully employed to determine the concentrations of PAHs in genuine soil and standard reference material, and the results were comparable to those of widely utilized EPA methodology.


Assuntos
Técnicas de Química Analítica/métodos , Indóis/síntese química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Polímeros/síntese química , Poluentes do Solo/isolamento & purificação , Solo/química , Compostos de Vinila/química , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Extração Líquido-Líquido , Fenômenos Magnéticos , Hidrocarbonetos Policíclicos Aromáticos/análise , Polimerização , Poluentes do Solo/análise
15.
Artigo em Inglês | MEDLINE | ID: mdl-31821967

RESUMO

Dry blood spot (DBS), a micro whole-blood sampling technique, enables rapid and self-blood collection; it is stable and economical. Currently, DBS filters require various sample preparation procedures specifically tailored for the target compounds, which are followed by GC-MS or LC-MS analysis. However, the small amounts of blood make the approach analytically challenging, mostly in terms of sensitivity and quantification. Herein, we introduce a new DBS concept for GC-compatible volatile to semi-volatile compounds in which DBS is directly coupled with thermal desorption analysis, thus eliminating time consuming treatments. Furthermore, to stabilize the target compound over the sampling DBS substrate, a commercial filter based on an extremely efficient trapping adsorption phase, styrene-divinylbenzene (SDVB), is first used. The performance of the new SDVB-DBS concept was demonstrated herein for monitoring the most volatile chemical warfare agent, sarin, which might be present in blood and the detection of which is usually challenging due to its rapid metabolism. This study encompasses adequate sampling and analysis method parametrization and validation, leading to a detection sensitivity of 100 pg sarin per 30 µL whole blood in 5-day-old samples, with a linear dynamic range of two orders of magnitude, adequate precision, and acceptable accuracy. Applying the method to an in-vivo mouse intranasal exposure experiment (3LD50 GB) enabled the successful detection of 25-90 ng mL-1 free sarin in blood samples drawn 2 min after exposure. The method's performance clearly emphasizes the potential of the new concept in "freezing the clock" for reactive whole blood media in pharmacokinetics and pharmacodynamics studies, as well as in applications in which informative and reliable monitoring of unstable target compounds and biomarkers is desired.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Sarina/sangue , Adsorção , Animais , Limite de Detecção , Modelos Lineares , Masculino , Camundongos , Camundongos Endogâmicos ICR , Reprodutibilidade dos Testes , Estireno/química , Compostos de Vinila/química
16.
Food Chem ; 310: 125801, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31711813

RESUMO

The influence on aroma compounds chips or staves and toasting degree have been analyzed in red wines aged for two periods of time. Ethyl propanoate, ethyl butanoate, ethyl octanoate, ethyl acetate, isoamyl acetate, isobutanol, 2-methyl-1-butanol, 2-phenylethanol, E-2-hexenol, octanal, nonanal, decanal, γ-nonalactone, furfural, 5-methylfurfural, 2-methoxy-4-vinylphenol and cis-whiskey lactone were the compounds that contribute the most to the aroma series profile. By means of principal components analysis, esters were related to the aging time; cis-whiskey lactone with the type of wood pieces and octanal, 5-methyl furfural and cis-whiskey lactone with the toasting degree. Star plot show that woody aroma compounds are dominant in wines aged with low toasting degree oak pieces, whereas medium plus toasted pieces increased the concentration of aroma compounds with fruity aroma descriptors. Wines with prominent fruity or woody aromas can be obtained depending upon the degree of toasting of wood pieces used for aging.


Assuntos
Compostos Orgânicos Voláteis/análise , Vinho/análise , Madeira , Análise de Alimentos , Indústria de Processamento de Alimentos/instrumentação , Indústria de Processamento de Alimentos/métodos , Furaldeído/análogos & derivados , Furaldeído/análise , Guaiacol/análogos & derivados , Guaiacol/análise , Lactonas/análise , Odorantes/análise , Romênia , Fatores de Tempo , Compostos de Vinila/análise , Madeira/química
17.
18.
Chemosphere ; 239: 124732, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499304

RESUMO

A polar modified post-cross-linked poly (divinylbenzene-co-ethyleneglycol-dimethacrylate) (PCL-PDE) resin was synthesized by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB), and a post-cross-linked reaction. After characterization, the adsorption behaviors of 5-hydroxymethylfurfural (5-HMF) on PCL-PDE resin were determined in comparison with the starting copolymers PDE resin. The equilibrium adsorption capacity of 5-HMF on PCL-PDE resin was much larger than PDE resin and the increase rate was greater than 52.6%. The equilibrium data of 5-HMF onto PCL-PDE resin were found to be better fitted by the Langmuir isotherm model. The kinetic data shows that the adsorption reached equilibrium in a short time (less than 20 min) can be fitted by the pore diffusion model (PDM) at various operating conditions. The effective pore diffusion coefficient was dependent upon adsorption temperature, and were 6.706 × 10-10, 8.958 × 10-10, 1.136 × 10-9 and 1.429 × 10-9 m2 s-1 at 288, 298, 308 and 318 K, respectively. Furthermore, the effects of feed flow rate (Qf = 0.6, 1.5, 3.0 and 6.0 mL min-1) and initial 5-HMF concentration (cf = 0.52, 1.02, 2.00 and 4.96 g L-1) on the adsorption were investigated systematically. Besides, a general rate model (GRM) was used to predict adsorption breakthrough curves of 5-HMF. The simulation results are highly consistent with the experimental data, indicating that the GRM can successfully simulate this process. In the desorption process, the desorption capacity reaches 99.6% of adsorbed capacity, suggesting that the PCL-PDE resin exhibited good reusability. Therefore, it could be suggested that the PCL-PDE resin has a potential application in the separation and purification of 5-HMF.


Assuntos
Resinas Acrílicas/química , Furaldeído/análogos & derivados , Resinas Acrílicas/síntese química , Adsorção , Reagentes para Ligações Cruzadas/química , Difusão , Furaldeído/química , Furaldeído/isolamento & purificação , Cinética , Metacrilatos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Compostos de Vinila/química
19.
Chemistry ; 26(13): 2947-2953, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31850549

RESUMO

PEG is the gold standard polymer for pharmaceutical applications, however it lacks degradability. Degradation under physiologically relevant pH as present in endolysosomes, cancerous and inflammatory tissues is crucial for many areas. The authors present anionic ring-opening copolymerization of ethylene oxide with 3,4-epoxy-1-butene (EPB) and subsequent modification to introduce acid-degradable vinyl ether groups as well as methacrylate (MA) units, enabling radical cross-linking. Copolymers with different molar ratios of EPB, molecular weights (Mn ) up to 10 000 g mol-1 and narrow dispersities (D<1.05) were prepared. Both the P(EG-co-isoEPB)MA copolymer and the hydrogels showed pH-dependent, rapid hydrolysis at pH 5-6 and long-term storage stability at neutral pH (pH 7.4). By designing the degree of polymerization and content of degradable vinyl ether groups, the release time of an entrapped protein OVA-Alexa488 can be tailored from a few hours to several days (hydrolysis half-life time t1/2 at pH 5: 13 h to 51 h).


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Concentração de Íons de Hidrogênio , Hidrólise , Metacrilatos/química , Polietilenoglicóis/química , Polimerização , Proteínas , Compostos de Vinila
20.
Anticancer Res ; 39(12): 6685-6691, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31810933

RESUMO

BACKGROUND/AIM: No effective therapeutics have yet been developed for pancreatic cancer. 2-Methoxy-4-vinyl phenol (2M4VP), a member of the class of phenols, has been demonstrated to have anti-inflammatory properties and cause cell cycle arrest making it an attractive candidate drug for the treatment of pancreatic cancer. MATERIALS AND METHODS: The effects of 2M4VP were examined in Panc-1 and SNU-213 human pancreatic cancer cells. RESULTS: 2M4VP had anticancer effects on pancreatic cancer cell lines, Panc-1 and SNU-213. 2M4VP reduced the viability of Panc-1 cells by inhibiting the expression of the cell nuclear antigen (PCNA) protein. 2M4VP also suppressed the migratory activity of both cell lines. In addition, treatment with 2M4VP effectively decreased the phosphorylation of Focal Adhesion Kinase (FAK) and AKT. CONCLUSION: 2M4VP might be used as a pancreatic cancer treatment supplement.


Assuntos
Movimento Celular/efeitos dos fármacos , Quinase 1 de Adesão Focal/antagonistas & inibidores , Guaiacol/análogos & derivados , Neoplasias Pancreáticas/tratamento farmacológico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Compostos de Vinila/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Quinase 1 de Adesão Focal/metabolismo , Guaiacol/farmacologia , Fator de Crescimento de Hepatócito/metabolismo , Humanos , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA