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1.
Medicina (B Aires) ; 80(3): 197-202, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32442933

RESUMO

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder due to a deficiency of enzymes involved in cortisol biosynthesis. In more than 90% of cases, CAH is secondary to deleterious mutations in the CYP21A2 gene leading to 21-hydroxilase deficiency (21OHD). The CYP21A2 gene is located on the short arm of chromosome 6 (6p21·3) and encodes the cytochrome P450C21 enzyme. Neonatal screening programs detect the classic forms of CAH-21OHD quantifying 17OH-progesterone in dried blood spots (DBS). This test is very sensitive, but it has a low specificity, requiring a second sample to confirm the result. In these cases, a second-tier test in the same sample may be useful. Our aim was to evaluate a DNA extraction method from DBS and assess the performance of such DNA in the molecular analysis of the CYP21A2 gene mutations. Twelve individuals, who presumably had CAH based on the initial neonatal screening results, were analyzed using DNA extracted from freshly collected blood on EDTA and DBS. The CYP21A2 gene was analyzed by automated sequencing of all exons and intron boundaries and MLPA analysis in DBS. Molecular analysis results from both extraction methods were compared. In this study, we show that DNA extracted from neonatal screening DBS is a useful tool to define CYP21A2 gene mutations in 21-OHD diagnostic confirmation for the newborn screening program and that its results are comparable to traditional genotyping.


Assuntos
Hiperplasia Suprarrenal Congênita/diagnóstico , Hiperplasia Suprarrenal Congênita/genética , Teste em Amostras de Sangue Seco/métodos , Mutação , Triagem Neonatal/métodos , Esteroide 21-Hidroxilase/genética , 17-alfa-Hidroxiprogesterona/análise , Alelos , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Masculino , Reação em Cadeia da Polimerase , Valores de Referência , Reprodutibilidade dos Testes , Espectrofotometria
2.
J Appl Oral Sci ; 28: e20190720, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428059

RESUMO

Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.


Assuntos
Peróxido de Carbamida/administração & dosagem , Peróxido de Hidrogênio/administração & dosagem , Luz , Fototerapia/métodos , Clareadores Dentários/administração & dosagem , Clareamento Dental/métodos , Adolescente , Adulto , Análise de Variância , Colorimetria , Terapia Combinada , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/efeitos da radiação , Sensibilidade da Dentina/induzido quimicamente , Feminino , Humanos , Masculino , Valores de Referência , Fatores de Risco , Espectrofotometria , Estatísticas não Paramétricas , Propriedades de Superfície/efeitos dos fármacos , Propriedades de Superfície/efeitos da radiação , Resultado do Tratamento , Adulto Jovem
3.
Int J Prosthodont ; 33(3): 277-284, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32320180

RESUMO

PURPOSE: To visually and spectrophotometrically determine the differences in the shades of maxillary anterior implant crowns and peri-implant soft tissues compared to a natural teeth control group. MATERIALS AND METHODS: A total of 44 patients restored with single implant-supported restorations were assessed after at least 6 months in function. Images of the implant crowns, peri-implant soft tissues, and their controls were captured using a spectrophotometer (SpectroShade Micro, Medical High Technologies). Visual assessment of shade differences between the implant crowns and peri-implant soft tissues and their controls were performed by the patients and four dental professionals using a visual analog scale (VAS). Analysis of variance was applied to detect differences between groups. RESULTS: The mean color differences (ΔE) between the implant crowns and peri-implant soft tissues and their respective controls were 4.8 ± 2.6 and 6.6 ± 2.7, respectively. A significant difference (P = .025) in mean ΔE values was observed only at the cervical third of the implant crowns. The patient group showed the highest mean VAS scores for shade matching of the implant crowns (8.4 ± 1.2) and peri-implant soft tissues (7.8 ± 1.6) with their respective controls. CONCLUSION: Spectrophotometric analysis showed significant shade differences at the cervical third of the implant crowns. The patients were more satisfied with the shade matching of their implant restorations than the dental professionals.


Assuntos
Coroas , Implantes Dentários para Um Único Dente , Cor , Humanos , Estudos Retrospectivos , Espectrofotometria
4.
Water Res ; 177: 115773, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32320850

RESUMO

True water color (TWC) is an important water quality indicator. However, despite many efforts for standardization of methods for TWC determination, there is still no consistency between visual and spectroscopic techniques. This study demonstrates that standard spectroscopic methods overestimate visual data from 21 to 47%, depending on methods involved. To retrieve relevant true water color values from spectral data, a new spectroscopic method is proposed. The method is based on the mathematical model of color perception by the standard observer implementing the dE2000 color difference in the L∗a∗b color space as calculated between blank and water samples. The method showed good agreement with the visual methods (comparator method and determination in Nessler cylinders) and the mean values between these methods. The mean relative difference between the proposed method and the mean of the two visual methods is only 2%. The method precision is independent from TWC in all measurement ranges and has Sr 0.3 mgPt-Co L-1 (df = 98), which is at least three times lower than for the standard methods. As such, it shows higher accuracy and precision. As a result, the proposed method can be used for TWC determination in environmental samples from 3.3 to 500 mgPt-Co L-1 with SD 0.3 mgPt-Co L-1 in all measuring ranges, making sample dilution unnecessary.


Assuntos
Percepção de Cores , Água , Cor , Espectrofotometria , Análise Espectral
5.
Einstein (Sao Paulo) ; 18: eAO5022, 2020.
Artigo em Inglês, Português | MEDLINE | ID: mdl-32215468

RESUMO

OBJECTIVE: To evaluate the effects of oxidative stress on insulin signaling in cardiac tissue of obese mice. METHODS: Thirty Swiss mice were equally divided (n=10) into three groups: Control Group, Obese Group, and Obese Group Treated with N-acetylcysteine. After obesity and insulin resistance were established, the obese mice were treated with N-acetylcysteine at a dose of 50mg/kg daily for 15 days via oral gavage. RESULTS: Higher blood glucose levels and nitrite and carbonyl contents, and lower protein levels of glutathione peroxidase and phosphorylated protein kinase B were observed in the obese group when compared with their respective control. On the other hand, treatment with N-acetylcysteine was effective in reducing blood glucose levels and nitrite and carbonyl contents, and significantly increased protein levels of glutathione peroxidase and phosphorylated protein kinase B compared to the Obese Group. CONCLUSION: Obesity and/or a high-lipid diet may result in oxidative stress and insulin resistance in the heart tissue of obese mice, and the use of N-acetylcysteine as a methodological and therapeutic strategy suggested there is a relation between them.


Assuntos
Acetilcisteína/farmacologia , Dieta Hiperlipídica , Depuradores de Radicais Livres/farmacologia , Resistência à Insulina/fisiologia , Miocárdio/metabolismo , Obesidade/metabolismo , Estresse Oxidativo/fisiologia , Animais , Glicemia/análise , Western Blotting , Peso Corporal , Fluoresceínas/análise , Humanos , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Carbonilação Proteica , Espécies Reativas de Oxigênio/análise , Valores de Referência , Espectrofotometria
6.
Food Chem ; 318: 126385, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32135417

RESUMO

Rice landraces of North-East India have wide bio-diversity but remained nutritionally uncharacterized. Nutritional profiling of 33 indigenous rice landraces from the state of Arunachal Pradesh, Northeast India, and effect milling was evaluated. Total dietary fiber (5.22 g/100 g) was significantly higher than high yielding or hybrid cultivars. Principal nutrient variability of brown rice were: ash (13% c. v.) > insoluble dietary fibre, IDF (12% c. v.) > protein (11.% c.v.) fat (11% c. v.). Compositional diversity exists among rice landraces. Average iron was lesser but zinc content was higher than popular high yielding cultivars. Nutrient changes due to milling were most profound for thiamin (-69%), IDF (-66%) followed by phytate (-66%). Nutritionally Arunachal rice landraces are comparable to high yielding cultivars with added advantage of significantly higher total dietary fiber and lower phytate content. Thus, Arunachal rice landraces represents an agronomically and nutritionally important pool for rice improvement/breeding.


Assuntos
Valor Nutritivo , Oryza/metabolismo , Cromatografia Líquida de Alta Pressão , Fibras na Dieta/análise , Índia , Ferro/análise , Oryza/química , Oryza/crescimento & desenvolvimento , Ácido Fítico/análise , Proteínas de Plantas/análise , Espectrofotometria , Zinco/análise
7.
Food Chem ; 319: 126435, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32155538

RESUMO

A microwave-assisted digestion method using diluted HNO3 was developed for further determination of Al, Ca, Cr, Cu, Fe, K, Mn, Mo and Ni in rice samples by ICP OES. The following optimized conditions were established after full factorial design: digestion time of 14 min, concentration of 1 mol L-1 HNO3 and 2.5 mL of H2O2. The efficiency in decomposing organic matter with diluted acid was higher than 89%. The methodology was validated using the SRM NIST 1568a Rice Flour and recovery tests, with agreement between the determined and certified/added concentration values, and RSD of up to 12%. The limits of detection of the method were in the range of 0.0087 mg kg-1 (Mn) to 1.6 mg kg-1 (Ca). In addition, a simple and inexpensive spectrophotometric method was proposed for the quantification of organic carbon in varied samples (carbohydrates, proteins, lipids) in the form of digested or solids.


Assuntos
Micro-Ondas , Ácido Nítrico/química , Oryza/química , Minerais/análise , Espectrofotometria
8.
Stomatologiia (Mosk) ; 99(1): 7-11, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32125295

RESUMO

PURPOSE: To determine the effect of whitening toothpastes on the color of a nanocomposite material using a spectrophotometer. MATERIAL AND METHODS: The study involved 50 samples from nanocomposite restoration material which were exposed under laboratory conditions to brushing with one of 4 types of toothpastes (control with no bleaching agents, peroxide paste with carbamide, abrasive and enzyme-based pastes). Using the parameters a, b and L obtained by spectrophotometry, delta E (ΔE) value was calculated. To determine the maximum and minimum A posteriori comparisons by the Scheffe method were used to influence the delta E parameter after exposure to the pastes. Oxygen-containing paste (OZPP) had a maximum effect on the increase of the ΔE parameter, ΔE=1.03 comparing to ΔE=0.20 in control toothpaste. The isolated effect of a toothbrush resulted in a large change in the parameter ΔE, compared to the effect of a controls. However, the ΔE does not indicate the clarification of the material, but only a change in color relative to the initial measurement. As a result of spectrophotometry and statistical data processing, it was found that all pastes had a sufficient effect on the color change for the device to determine, but this change was not noticeable to the human eye.


Assuntos
Nanocompostos , Clareadores Dentários , Clareamento Dental , Humanos , Espectrofotometria , Cremes Dentais
9.
Dental Press J Orthod ; 25(1): 26-27, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32215474

RESUMO

OBJECTIVE: To qualitatively and quantitatively assess the color changes effect and the color stability of the resin infiltrant on white spot lesions (WSLs), in comparison with nano-hydroxyapatite (nano-HA) toothpaste and microabrasion. METHODS: WSLs were artificially created on sixty human premolars enamel surfaces and randomly assigned to equal four groups (n = 15 each): nano-HA toothpaste, microabrasion (Opalusture), resin infiltrant (Icon) treatment, or artificial saliva (control group). The color change (ΔE) of each specimen was measured by dental spectrophotometer (Vita Easyshade) at different time points: baseline, after WSLs' creation, after application of treatments, one month, three and six months after treatments application. RESULTS: The ΔE value did not differ significantly for the four groups at baseline measurement before treatment (p> 0.05). Icon resin infiltrant improved the color of WSLs significantly immediately after its application, giving the lowest ΔE value (3.00 ± 0.59), when compared to other treatments (p< 0.001). There were no significant changes in ΔE (p> 0.05) for all groups during the follow up intervals (one month, three and six months after treatments application). CONCLUSION: Resin infiltrant can improve the color of WSLs and restore the natural appearance of enamel better than nano-HA toothpaste and microabrasion.


Assuntos
Cárie Dentária , Cor , Esmalte Dentário , Humanos , Resinas Sintéticas , Espectrofotometria
10.
Head Face Med ; 16(1): 2, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32070379

RESUMO

BACKGROUND: Manufacturers of orthodontic aligners suggest that users remove appliances every time they consume solid foods or any drink (except water). This is to avoid a color change within the clear thermoplastic material of which they are made. However, limited quantitative evidence exists to guide users and practitioners in this regard. Herein, we evaluated the color stability of the polymer forming three different American brands of aligners and the stain-removal potential of two cleansers to provide such guidelines. METHODS: The removable appliances (300 specimens, 100 per brand) were exposed to different staining agents common in a regular diet (coffee, black tea, red wine, cola) or to a control solution in vitro over 12 h or 7 days. The three brands evaluated were Invisalign®, ClearCorrect® and Minor Tooth Movement®. These were then cleaned by using either Invisalign® cleaning crystals or the Cordless Sonic Cleaner combined with a Retainer Brite® tablet. The CIELAB color space approach was used to compare color changes (ΔE) in aligners before immersion (T0), after a 12-h exposure (T1), after a 7-day exposure (T2) and after cleaning (T3). Statistical methods (Levene's test, ANOVA, Brunner-Langer model, Tukey's range test and t-test) were used to identify interactions between the brands themselves or between the brands and the cleaning methods. Statistical analyses were performed at the .05 significance level. RESULTS: A 12-h or 7-day exposure to instant coffee or red wine significantly colored the Invisalign® aligners compared to the two other brands. Black tea created an important extrinsic color change for all three brands after 7 days. Clinically, both cleaning methods showed a better efficacy in removing stains from black tea compared to other staining agents. CONCLUSIONS: The Invisalign® aligners were more prone to pigmentation than the ClearCorrect® or the Minor Tooth Movement® devices after an exposure to coffee or red wine. Black tea caused important stains on the surface of the three tested brands. Both cleansing methods performed similarly.


Assuntos
Café , Colorimetria , Aparelhos Ortodônticos , Teste de Materiais , Espectrofotometria , Coloração e Rotulagem
11.
Sud Med Ekspert ; 63(1): 42-46, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32040087

RESUMO

The purpose of the study is to develop a method for detecting, isolating and quantifying lamivudine in biological substances. Lamivudine was isolated by liquid-liquid and solid phase extraction. The conditions for isolating lamivudine (extractant, pH of the medium, electrolyte, time and frequency of extraction) from aqueous solutions were selected and methods were developed for isolating it from biological substances, including urine, saliva and liver, using liquid-liquid and solid phase extraction methods. Qualitative and quantitative analysis of lamivudine in extracts from urine, saliva and liver was performed by thin layer chromatography, UV spectrophotometry and high-performance liquid chromatography. A validation assessment of the developed techniques indicates their suitability for chemical and toxicological analysis of lamivudine.


Assuntos
Lamivudina/análise , Fígado/química , Saliva/química , Urinálise , Cromatografia Líquida de Alta Pressão , Cromatografia em Camada Delgada , Humanos , Extração em Fase Sólida , Espectrofotometria
12.
J Photochem Photobiol B ; 204: 111804, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32007677

RESUMO

The ubiquitous influence of double stranded RNAs in biological events makes them imperative to gather data based on specific binding procedure of small molecules to various RNA conformations. Particular interest may be attributed to situations wherein small molecules target RNAs altering their structures and causing functional modifications. The main focus of this study is to delve into the interactive pattern of two small molecule phenothiazinium dyes, methylene blue and new methylene blue, with three duplex RNA polynucleotides-poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C) by spectroscopic and molecular modeling techniques. Analysis of data as per Scatchard and Benesi-Hildebrand methodologies revealed highest affinity of these dyes to poly(A).poly(U) and least to poly(I).poly(C). In addition to fluorescence quenching, viscometric studies also substantiated that the dyes follow different modes of binding to different RNA polynucleotides. Distortion in the RNA structures with induced optical activity in the otherwise optically inactive dye molecules was evidenced from circular dichroism results. Dye-induced RNA structural modification occurred from extended conformation to compact particles visualized by atomic force microscopy. Molecular docking results revealed different binding patterns of the dye molecules within the RNA duplexes. The novelty of the present work lies towards a new contribution of the phenothiazinium dyes in dysfunctioning double stranded RNAs, advancing our knowledge to their potential use as RNA targeted small molecules.


Assuntos
Azul de Metileno/análogos & derivados , Azul de Metileno/química , RNA de Cadeia Dupla/química , Sítios de Ligação , Corantes/química , Azul de Metileno/metabolismo , Microscopia de Força Atômica , Simulação de Acoplamento Molecular , Conformação de Ácido Nucleico , Fenotiazinas/química , Poli C/química , Poli C/metabolismo , Poli G/química , Poli G/metabolismo , RNA de Cadeia Dupla/metabolismo , Espectrometria de Fluorescência , Espectrofotometria , Viscosidade
13.
Oper Dent ; 45(3): E105-E113, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053456

RESUMO

BACKGROUND: This study investigated the hardness and color stability of five resin composites subjected to different polishing methods following immersion in distilled water or lactic acid for up to three months. METHODS AND MATERIALS: Three nanohybrid, Paradigm (3M ESPE), Estelite Sigma Quick (Tokuyama), Ice (SDI), and two microhybrid, Filtek P60 and Filtek Z250, composites were examined. Disc-shaped specimens (10×1.5 mm) were prepared and immersed in distilled water for 24 hours then polished using either silicon carbide paper, the Shofu polishing system or were left unpolished (control). The CIE values and microhardness were determined using a spectrophotometer and digital Vickers hardness tester, respectively (n=10) after one, 45, and 90 days of storage in distilled water or lactic acid. Data were analyzed using analysis of variance, Tukey test, and Pearson correlation coefficient. RESULTS: Ice exhibited the greatest color change, yet Paradigm and Filtek P60 demonstrated the least. Overall, discoloration of tested materials was multifactorial and the effect of storage media depended on the material, polishing method and time interval. The greatest hardness was obtained for Paradigm and the lowest for Estelite. Hardness was found to be significantly higher in lactic acid after 45 days (p=0.014) and even higher after 90 days (p<0.001) compared with distilled water. CONCLUSIONS: An acidic environment did not adversely affect color stability or microhardness of the resin composites. There was a significantly mild reverse correlation between hardness and color change in both storage media.


Assuntos
Resinas Compostas , Cor , Dureza , Teste de Materiais , Espectrofotometria , Propriedades de Superfície
14.
Chemosphere ; 246: 125718, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31918082

RESUMO

The presence and mobilization of toxic metal cations represents under many aspects a current and important problem in the environmental field. In this research, as cation lead (II) ion was studied. The formation of complexes between glutathione and lead (II) was studied at 25 °C and in 1.00 M NaCl as ionic medium by means of measurements of electromotive force (e.m.f.) of cells containing glass and lead amalgam electrodes. In the same experimental conditions, the protonation constants of glutathione were determined potentiometrically, using a cell containing the glass electrode. In the same experimental conditions, by considering glutathione (GSH) completely deprotonated, four protonation constants were determined. Potentiometric data could be explained by assuming the formation of 1:1 complexes between GSH and Pb2+ and with the participation of hydrogen ions. The stability constants of the assumed complexes were determined. The 1:1 ratio between GSH and lead (II) was confirmed by spectrophotometric investigations. Measurements by Infrared Rays (IR) and protonic Nuclear Magnetic Resonance (1H NMR) provide information on the structure of the found complexes.


Assuntos
Glutationa/metabolismo , Chumbo/metabolismo , Ligantes , Cátions , Glutationa/química , Concentração de Íons de Hidrogênio , Chumbo/química , Espectroscopia de Ressonância Magnética , Potenciometria , Prótons , Espectrofotometria
16.
Food Chem ; 313: 126045, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31954278

RESUMO

The polyphenolic content and the antioxidant capacity of seven tannins with different botanical origin were measured with spectrophotometric methods (Folin-Ciocalteu, Total Polyphenols Index, DPPH, FRAP), HPLC (phloroglucinolysis), voltammetric analysis (Linear Sweep Voltammetry, LSV). The oxygen consumption rate (OCR) was measured in an oxygen saturated model wine solution, containing transition metals and metabisulphite, with a noninvasive luminescence-based technology. The results showed a high variability in polyphenolic concentration related to the botanical origin of tannins. The OCR determined over 21 days was described by quadratic equations, with coefficients varying with tannin botanical origin, dose and SO2 concentration. The tannins ranked differently for antioxidant capacity, depending on the kind of test. The oxygen consumption parameters were positively correlated only with the LSV data measured with anodic current between 100 and 1200 mV (LSV1200mV) and with the FRAP index.


Assuntos
Antioxidantes/química , Polifenóis/química , Taninos/química , Vinho/análise , Cromatografia Líquida de Alta Pressão , Oxigênio/química , Consumo de Oxigênio , Espectrofotometria
17.
J Photochem Photobiol B ; 203: 111768, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31931383

RESUMO

In vitro callus cultures of Verbena officinalis L. were maintained on solid Murashige and Skoog medium, enriched with 1 mg dm-3 BA and 1 mg dm-3 IBA under LED lights (red, blue, red/blue 70%/30%), in darkness and under control fluorescent lamps. The measurements of 2 phenylpropanoid glycosides (verbascoside and isoverbascoside) and 23 phenolic acids were performed in methanolic extracts from the biomass collected after 2-, 3- and 4-week growth cycles using the HPLC-DAD method. The presence of verbascoside, isoverbascoside and additionaly 7 phenolic acids (protocatechuic, chlorogenic, vanillic, caffeic, ferulic, o-coumaric and m-coumaric acids) was confirmed in all extracts. Blue and red/blue lights stimulated the accumulation of verbascoside (max. of 6716 and 6023 mg 100 g-1 DW after a 4-week growth cycle) and isoverbascoside (max. 333 and 379 mg 100 g-1 DW also after 4 weeks). The maximum amounts of verbascoside and isoverbascoside were respectively 1.8- and 7.0-fold higher than under the control conditions. Phenolic acids were accumulated in different amounts, and the maximum total amounts ranged from 36 to 65 mg 100 g-1 DW. LED lights also stimulated their accumulation in comparison with darkness and control. The main phenolic acids included: m-coumaric acid (max. 39 mg 100 g-1 DW), ferulic acid (max. 12 mg 100 g-1 DW), and protocatechuic acid (max. 13 mg 100 g-1 DW). Additionally, the quantities of photosynthetic pigments (chlorophyll a, b and carotenoids) were estimated in acetonic extracts using spectrophotometry. Red/blue light stimulated the biosynthesis of pigments (max. total content 287 µg g-1 FW after 4-week growth cycles). This is the first study describing the effect of LED lights on the production of phenylpropanoid glycosides and phenolic acids in V. officinalis callus cultures. Very high amounts of verbascoside and isoverbascoside are interesting from a practical point of view.


Assuntos
Glucosídeos/metabolismo , Hidroxibenzoatos/metabolismo , Luz , Fenóis/metabolismo , Verbena/metabolismo , Biomassa , Carotenoides/análise , Clorofila/análise , Clorofila A/análise , Cromatografia Líquida de Alta Pressão , Glucosídeos/análise , Hidroxibenzoatos/análise , Fenóis/análise , Fotossíntese/efeitos da radiação , Análise de Componente Principal , Análise de Regressão , Espectrofotometria
18.
J Phys Chem Lett ; 11(3): 1030-1037, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31967828

RESUMO

Very recently, the bulk synthesis of cyclo-N5- from arylpentazole through the treatment with m-chloroperbenzonic acid (m-CPBA) and ferrous bisglycinate ([Fe(Gly)2]) (Zhang, C., et al. Science 2017, 355, 374) has greatly promoted the application of pentazolate anion as a novel high-performance energetic material. Yet the mechanism for this reaction is still unexplored. Herein we perform mechanistic studies on the selective C-N bond cleavage in arylpentazole by using density functional theory methods. The direct C-N bond activation by m-CPBA was computed to be kinetically inaccessible. Instead, the oxidation of [Fe(Gly)2] by m-CPBA is much favorable, which leads to the generation of a high-valent iron(IV)-oxo product. The Fe(IV)-oxo intermediate has been examined by UV-vis absorption spectra experiments and further verified by excited-state calculations. It is found that the Fe(IV)-oxo serves as the key intermediate for the C-N bond activation of arylpentazole and the cyclo-N5- generation. Our calculations clarified the key mechanistic details of the cyclo-N5- generation, and the factors that affect the production yield are further discussed.


Assuntos
Clorobenzoatos/química , Compostos Ferrosos/química , Glicina/química , Modelos Moleculares , Pentilenotetrazol/química , Carbono/química , Nitrogênio/química , Oxirredução , Teoria Quântica , Espectrofotometria , Termodinâmica
19.
Chem Commun (Camb) ; 56(10): 1505-1508, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31917382

RESUMO

A bio-inspired, ATP-driven nucleation growth assembly is demonstrated using an amphiphilic naphthalene diimide (NDI) derivative appended with guanidinium receptors to promote specific salt-bridge type interaction with nucleotide phosphates. Detailed spectroscopic and microscopic probing revealed a pathway-dependent co-operative self-assembly to yield two-dimensional and scrolled nano-tubular bilayer assemblies under kinetic and thermodynamic conditions, respectively.


Assuntos
Trifosfato de Adenosina/química , Imidas/química , Naftalenos/química , Guanidina/química , Ligação de Hidrogênio , Cinética , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Espectrofotometria , Temperatura , Termodinâmica
20.
J Photochem Photobiol B ; 204: 111787, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31958676

RESUMO

The sensitivity for singlet oxygen (1O2) of two convenient 1O2 probes, 1,3-diphenylisobenzofuran (DPBF) and 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA), has been investigated in different aqueous environments. Both probes are commercially available at reasonable cost and can be used with standard UV-vis spectrometers. Although DPBF is not soluble in neat water and is not specific to the detection of 1O2, it has very high, essentially diffusion-limited, reactivity towards 1O2; it can trap up to 50% of all 1O2 created in alcohol/water or micellar solution, and even more when replacing H2O by D2O, which makes it highly useful when the process under investigation does not yield much 1O2. On the other hand, ABDA has a much lower reactivity, reacting with only 2% of the singlet oxygen generated in H2O, as well as a smaller extinction coefficient, resulting in a much smaller spectroscopic response, but is soluble in neat water and is specific for 1O2, allowing for discrimination from other reactive oxygen species. The results presented here not only allow a comparative assessment of the usefulness of the two 1O2 probes, but also provide a reference for an accurate absolute quantification of the amount of 1O2 generated in an experiment from the observed absorbance bleach.


Assuntos
Antracenos/química , Benzofuranos/química , Oxigênio Singlete/análise , Água/química , Óxido de Deutério/química , Luz , Solventes/química , Espectrofotometria
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