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1.
Ecotoxicol Environ Saf ; 202: 110924, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800211

RESUMO

Fabrication of poly-(N-isopropylmethacrylamide-co-methacrylic acid) [p(NMA)] microgels to be utilized as microreactors to synthesize stable Ag nanoparticles for catalytic reductive degradation of dyes has been addressed in this work. Both p(NMA) microgel and Ag-p(NMA) hybrid microgel systems have been analyzed by Fourier transform infra-red and Dynamic light scattering, Ultraviolet-Visible spectroscopy, X-ray diffraction and Transmission electron microscopy. Catalytic activity of Ag-p(NMA) towards reductive degradation of Congo Red (CR), Methyl Orange (MO) and Alizarin Yellow (AY) was investigated under different operating conditions. Spectrophotometry was employed to check the progress of reaction while the rate constant (kapp) value of degradation reaction was determined under various conditions to optimize reaction parameters for rapid and economical degradation of these dyes. An increase in kapp value was observed by increasing feed content of dye up to a certain value that decreases again by further increment in dye concentration which reflects that catalysis follows Langmuir-Hinshelwood mechanism. A gradual increase in the kapp value was also observed with increasing quantity of hybrid microgel used as a catalyst. By comparing kapp values of degradation of aforementioned dyes, it was found that Ag-p(NMA) hybrid microgel gives better activity for MO dye degradation in comparison to catalytic degradation of CR and AY.


Assuntos
Compostos Azo/química , Nanopartículas Metálicas/química , Prata/química , Catálise , Corantes/química , Vermelho Congo/química , Hidrogéis/química , Microscopia Eletrônica de Transmissão , Polímeros/química , Espectrofotometria , Difração de Raios X
2.
Int J Esthet Dent ; 15(3): 306-316, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760925

RESUMO

The aim of this study was to evaluate, in vivo, the immediate masking effect of white spot lesions (WSLs) treated with an infiltrant resin (IR). The investigation was conducted on 40 young adolescent and adult patients (11 to 23 years old) who presented with at least one permanent maxillary or mandibular anterior tooth with active WSLs on the enamel (ICDAS score 2). Before resin infiltration, the color of both the WSLs and the sound adjacent enamel (SAE) was evaluated by a digital spectrophotometer (CIELab). Subsequently, a resin infiltration technique (Icon) was performed on the WSLs according to the manufacturer's instruction. At the end of the clinical session, the color of the IR was evaluated. The color difference (ΔE) was calculated between WSL × SAE, WSL × IR, and IR × SAE, and then analyzed using one-way analysis of variance (ANOVA), followed by the Tukey's test. The L*, a*, and b* values of WSL, SAE, and IR were compared using the Student's t test for related samples (α = 5%). The ΔE observed was 5.93 ± 0.41 on the WSL × IR comparison, and 5.77 ± 0.41 on the IR × S AE one, indicating that the color of the WSL changed after treatment, but that the infiltration did not fully camouflage the WSLs when compared with the SAE. The lightness was higher for the SAE than for the IR. It was concluded that the IR treatment was not able to camouflage the color of the WSLs when compared with the SAE. However, the treatment was able to attenuate the discoloration of the demineralized dental enamel.


Assuntos
Cárie Dentária , Esmalte Dentário , Adolescente , Adulto , Criança , Cor , Humanos , Resinas Sintéticas , Espectrofotometria , Adulto Jovem
3.
J Chromatogr A ; 1626: 461377, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797853

RESUMO

This study reports the use ofa natural deep eutectic solvent (NADES) with hollow fiber-microporous membrane liquid-liquid microextraction (HF-MMLLE) for the multiclass determination of 11 compounds classified as emerging contaminantsin water. Different deep eutectic solvents were synthetized and Thymol: Camphor (1:1 molar fraction) wasused as extraction solvent. The Thymol:Camphor was impregnated into the polypropylene membrane porous for 10 min, replacing commonly used solvents (ex. hexane and octanol). The optimized parameters were obtained by multi and univariate models. Extractions were carried out for 50 min using 1.5 mL of water sample at pH 6 and without addition of salt while desorption was made in a mixture of acetone: methanol (3:1, v/v) for 15 min. Separation/quantification was conducted by HPLC with a diode array detection (DAD)and calibration curves were obtained for each analyte. Determination coefficients higher than 0.9906 and limits of detection ranged from 0.3 to 6.1 µg L-1. Intraday precision (n = 3) ranged from 1.6 to 18.4% and inter day from 5.0 to 21.3%. Relative recoveries were performed in tap and stream water and ranged from 64 to 123%.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Solventes/química , Poluentes Químicos da Água/análise , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Polipropilenos/química , Porosidade , Espectrofotometria , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/normas
4.
J Chromatogr A ; 1626: 461379, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797854

RESUMO

Ordered porous materials are attracting enormous attention due to their uniform pore structures, particularly the magnetic photonic crystal microspheres (PCMs) which not only possess unique photonic crystal structure but also can achieve separation easily based on magnet. Here, a two-phase microfluidic self-assembly synthetic system was established simply and employed for the preparation of three dimensional PCMs (3DPCMs) by using the emulsion droplet approach. One phase (dispersed phase) was an aqueous emulsion containing Fe3O4, silica (SiO2) and polystyrene (PS) nanoparticles; another phase (continuous phase) was pure silicone oil. The droplets were formed by introducing the dispersed phase into the continuous phase through a tee valve. By heating the droplets, the water would evaporate and the nanoparticles would finally assemble into solid microspheres, which could be changed into macroporous 3DPCMs after removal of the PS nanoparticles by calcination. The contents and particle sizes of Fe3O4, SiO2 and PS nanoparticles in the dispersed phase were investigated in detail and optimized to prepare macroporous magnetic 3DPCMs with high quality. The morphologies, surface crystal structure, magnetic property, particle size distribution, specific surface area and pore size of the macroporous magnetic 3DPCMs were characterized. The expected 3DPCM displayed regular and uniform photonic crystal structure, narrow particle size distribution and strong magnetic property. The macroporous magnetic 3DPCMs grafted with vomitoxin (DON)-antibodies could be applied for selective enrichment of DON in real samples.


Assuntos
Magnetismo , Microfluídica/métodos , Microesferas , Tricotecenos/análise , Anticorpos/imunologia , Cromatografia Líquida de Alta Pressão , Óxido Ferroso-Férrico/química , Contaminação de Alimentos/análise , Nanopartículas/química , Tamanho da Partícula , Poliestirenos/química , Porosidade , Dióxido de Silício/química , Espectrofotometria , Tricotecenos/imunologia
5.
J Chromatogr A ; 1626: 461392, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797861

RESUMO

Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6%. For 60 nm sized PSNPs, a larger deviation of 10.6% between both methods was observed, which is attributed to the lower separation resolution.


Assuntos
Eletroforese Capilar/métodos , Fracionamento por Campo e Fluxo/métodos , Nanopartículas/química , Poliestirenos/química , Tamanho da Partícula , Dodecilsulfato de Sódio/química , Espectrofotometria
6.
J Enzyme Inhib Med Chem ; 35(1): 1539-1544, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32746637

RESUMO

Coronavirus disease 2019 (COVID-19) has been a pandemic disease of which the termination is not yet predictable. Currently, researches to develop vaccines and treatments is going on globally to cope with this disastrous disease. Main protease (3CLpro) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the good targets to find antiviral agents before vaccines are available. Some flavonoids are known to inhibit 3CLpro from SARS-CoV which causes SARS. Since their sequence identity is 96%, a similar approach was performed with a flavonoid library. Baicalin, herbacetin, and pectolinarin have been discovered to block the proteolytic activity of SARS-CoV-2 3CLpro. An in silico docking study showed that the binding modes of herbacetin and pectolinarin are similar to those obtained from the catalytic domain of SARS-CoV 3CLpro. However, their binding affinities are different due to the usage of whole SARS-CoV-2 3CLpro in this study. Baicalin showed an effective inhibitory activity against SARS-CoV-2 3CLpro and its docking mode is different from those of herbacetin and pectolinarin. This study suggests important scaffolds to design 3CLpro inhibitors to develop antiviral agents or health-foods and dietary supplements to cope with SARS-CoV-2.


Assuntos
Infecções por Coronavirus/tratamento farmacológico , Flavonoides/química , Pneumonia Viral/tratamento farmacológico , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/química , Antivirais/química , Betacoronavirus , Desenho de Fármacos , Transferência Ressonante de Energia de Fluorescência , Humanos , Simulação de Acoplamento Molecular , Pandemias , Inibidores de Proteases/química , Ligação Proteica , Conformação Proteica , Espectrofotometria , Triptofano/química
7.
Stomatologiia (Mosk) ; 99(3): 27-31, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32608945

RESUMO

THE AIM: Clinical analysis of the effectiveness of photodynamic tooth whitening according to the spectrophotometric method. MATERIAL AND METHODS: Photodynamic tooth whitening was performed in 35 patients aged 20-45 years, on the teeth of the frontal group. To record the optical characteristics of enamel, the spectrophotomerism method was used. RESULTS: The study reliably shows that the average change in color saturation «C¼ ranged from 0.5 to 2 units. The optical characteristic of luminosity "L" before and after photodynamic exposure remained within the limits of healthy enamel, and the optical characteristic of whiteness on the scale of whitened teeth was 2 units. CONCLUSION: The method of photodynamic therapy can be used in dental practice to conduct a teeth whitening procedure.


Assuntos
Clareadores Dentários , Clareamento Dental , Dente , Adulto , Cor , Esmalte Dentário , Humanos , Pessoa de Meia-Idade , Espectrofotometria , Adulto Jovem
8.
Mar Pollut Bull ; 158: 111363, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32568079

RESUMO

This research describes the application of magnetic molecularly imprinted nano-sized polymers (MMIPs) for the selective extraction and fast detection of malachite green (MG) from marine sediment samples followed by UV-Vis spectrophotometry. The novel material was prepared by surface imprinting using methacrylic acid as the functional monomer for fixing the template molecules. The polymers obtained at each step were thoroughly studied by transmission electron microscopy, FTIR spectroscopy and thermogravimetric analysis. Simultaneously, the adsorption performances of the resulting nanoparticles were analysed in detail and an excellent affinity with the MG was revealed. Further, the main parameters of magnetic molecular imprinted solid-phase extraction (MMIP-SPE) were screened via multivariate optimization methods. The magnetic nanoparticles were used as special adsorbents to directly extract MG from crude marine sediment extracts. The developed method exhibits satisfactory recoveries from the spiked samples, ranging from 80.40 to 92.96% with an RSD of less than 5.18% (n = 3).


Assuntos
Impressão Molecular , Polímeros , Adsorção , Sedimentos Geológicos , Fenômenos Magnéticos , Corantes de Rosanilina , Extração em Fase Sólida , Espectrofotometria
9.
Food Chem ; 329: 127177, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512396

RESUMO

Carmine is an artificial colorant commonly used by fraudulent food business participants in black tea adulteration, for purpose of gaining illegal profits. This study combined spectrophotometry with machine learning for rapid detection of carmine in black tea based on the spectral characteristics of tea infusion. The qualitative model demonstrated an accuracy rate of 100% for successful identification of the presence/absence of carmine in black tea. For quantitative analysis, the R2 between carmine concentrations generated according to spectral characteristics and those determined with HPLC was 0.988 and 0.972, respectively, for black tea samples involved in the test subset and an independent dataset II. Paired t-test indicated that the difference was statistically insignificant (P values of 0.26 and 0.44, respectively). The method established in this study was rapid and reliable for detecting carmine in black tea, and thus could be used as a useful tool to identify black tea adulteration in market.


Assuntos
Carmim/análise , Chá/química , Camellia sinensis , Cromatografia Líquida de Alta Pressão , Análise de Alimentos , Espectrofotometria , Chá/metabolismo
10.
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
11.
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
12.
J Esthet Restor Dent ; 32(6): 586-592, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32400106

RESUMO

OBJECTIVE: To evaluate dental prophylaxis influence in tooth color assessment with the use of different methods. MATERIALS AND METHODS: Volunteers were consecutively recruited and screened according to appropriate inclusion/exclusion criteria. Each participant's upper right central incisive and canine color was measured before and after dental prophylaxis with a one-week interval. Tooth color assessment was performed by calibrated operators and the patient using a VITA Classical shade guide and by spectrophotometric methods with a proper device (SpectroShade). Color was reported as mean with SD of Commission Internationale De l'Eclairage (CIE) L*a*b* values, ΔEab and ΔE00 . One-way analysis of variance and Tukey post hoc were performed to assess differences between methods and paired t test for assessing differences in tooth color coordinates after dental prophylaxis. Values of P < .05 were taken as significant. RESULTS: Fifty patients were included. Self-assessed dental prophylaxis effects equated to a significantly different mean ΔE00 value of 2.3 ± 1.7 (P < .01), when compared to the calibrated operator reported 0.8 ± 1.1 and the spectrophotometer 1.0 ± 0.5. Half of volunteer's ΔE00 values surpassed the acceptability threshold, when compared to 28% from investigator and 10% from spectrophotometer. CONCLUSION: Performing a dental prophylaxis did have an influence in tooth color perception with a higher self-perceived effect in the patient assessment. CLINICAL SIGNIFICANCE: The results of this study suggest that performing professional dental prophylaxis presented a perceived effect in tooth color regardless of the method used being that patients precepted whiter and less yellowish teeth. Since extrinsic stain is considered as one of the factors that could influence tooth color assessment, performing professional dental prophylaxis prior to composite or ceramic color selection in anterior teeth restorations could consequently increase treatment predictability.


Assuntos
Dente , Cerâmica , Cor , Profilaxia Dentária , Humanos , Pigmentação em Prótese , Espectrofotometria
14.
Chemosphere ; 251: 126626, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443247

RESUMO

Three spectrophotometric methods have been developed and compared for the quantification of low concentrations (0.03-63 µM) of aqueous permanganate in neutral pH conditions. Although permanganate is a widely used oxidant in drinking water and wastewater treatment, no widely accepted method of quantification has been reported to date. While one method presented does not require the need for any reagent chemicals (direct spectrophotometric analysis), it yielded a relatively low molar absorption coefficient of 3340 M-1 cm-1 at 525 nm and a level of detection (LOD) and quantification (LOQ) of 0.45 and 1.51 µM, respectively. Some instability of permanganate species during direct quantification was found to occur over 60 min, with a total decrease of 0.002 (arbitrary units) of absorbance, equivalent to a decrease in concentration of 0.6 µM. Beyond 60 min, no further degradation was observed. Indirect spectrophotometric analyses using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and sodium iodide (NaI) provided a significantly more sensitive method for permanganate quantification, yielding molar absorption coefficients of 140,030 and 61,130 M-1 cm-1, respectively. The LOD and LOQ were determined to be 0.01 and 0.03 µM for the ABTS method and 0.02 and 0.08 µM for the NaI method, respectively. Although conservative and accurate limits of quantification for both the ABTS and NaI methods are presented, which should be sufficient of most practical applications, lower limits may be possible with further refinement of the methods.


Assuntos
Compostos de Manganês/análise , Óxidos/análise , Espectrofotometria/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Limite de Detecção , Padrões de Referência , Espectrofotometria/instrumentação
15.
J Plant Physiol ; 249: 153161, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32353607

RESUMO

Optical leaf profiles depend on foliar pigment type and content, as well as anatomical aspects and cellular ultrastructure, whose effects are shown in several species. Monocotyledon and Dicotyledon plants presenting natural pigment content variations and anatomical alterations were analyzed. Each plant species displays its own spectral signatures, which are, in turn, influenced by foliar pigment class (composition) and concentration, as well as anatomical and ultrastructural plant cell characteristics. Plants with no anthocyanin displayed increased reflectance and transmittance in the green spectral region (501-565 nm), while values decreased in the presence of anthocyanin. At wavelengths below 500 nm (350-500 nm), strong overlapping signatures of phenolics, carotenoids, chlorophylls, flavonoids and anthocyanins were observed. Using a partial least squares regression applied to 350-700 nm spectral data allowed for accurate estimations of different foliar pigment levels. In addition, a PCA and discriminant analysis were able to efficiently discriminate different species displaying spectra overlapping. The use of absorbance spectra only was able to discriminate species with 100 % confidence. Finally, a discussion on how different wavelengths are absorbed and on anatomical interference of light interaction in leaf profiles is presented.


Assuntos
Pigmentos Biológicos/análise , Folhas de Planta/fisiologia , Espectrofotometria/métodos , Cordyline/fisiologia , Philodendron/fisiologia , Poaceae/fisiologia , Especificidade da Espécie , Tradescantia/fisiologia
16.
PLoS Med ; 17(5): e1003084, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32407380

RESUMO

BACKGROUND: The radical cure of Plasmodium vivax and P. ovale requires treatment with primaquine or tafenoquine to clear dormant liver stages. Either drug can induce haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, necessitating screening. The reference diagnostic method for G6PD activity is ultraviolet (UV) spectrophotometry; however, a universal G6PD activity threshold above which these drugs can be safely administered is not yet defined. Our study aimed to quantify assay-based variation in G6PD spectrophotometry and to explore the diagnostic implications of applying a universal threshold. METHODS AND FINDINGS: Individual-level data were pooled from studies that used G6PD spectrophotometry. Studies were identified via PubMed search (25 April 2018) and unpublished contributions from contacted authors (PROSPERO: CRD42019121414). Studies were excluded if they assessed only individuals with known haematological conditions, were family studies, or had insufficient details. Studies of malaria patients were included but analysed separately. Included studies were assessed for risk of bias using an adapted form of the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Repeatability and intra- and interlaboratory variability in G6PD activity measurements were compared between studies and pooled across the dataset. A universal threshold for G6PD deficiency was derived, and its diagnostic performance was compared to site-specific thresholds. Study participants (n = 15,811) were aged between 0 and 86 years, and 44.4% (7,083) were women. Median (range) activity of G6PD normal (G6PDn) control samples was 10.0 U/g Hb (6.3-14.0) for the Trinity assay and 8.3 U/g Hb (6.8-15.6) for the Randox assay. G6PD activity distributions varied significantly between studies. For the 13 studies that used the Trinity assay, the adjusted male median (AMM; a standardised metric of 100% G6PD activity) varied from 5.7 to 12.6 U/g Hb (p < 0.001). Assay precision varied between laboratories, as assessed by variance in control measurements (from 0.1 to 1.5 U/g Hb; p < 0.001) and study-wise mean coefficient of variation (CV) of replicate measures (from 1.6% to 14.9%; p < 0.001). A universal threshold of 100% G6PD activity was defined as 9.4 U/g Hb, yielding diagnostic thresholds of 6.6 U/g Hb (70% activity) and 2.8 U/g Hb (30% activity). These thresholds diagnosed individuals with less than 30% G6PD activity with study-wise sensitivity from 89% (95% CI: 81%-94%) to 100% (95% CI: 96%-100%) and specificity from 96% (95% CI: 89%-99%) to 100% (100%-100%). However, when considering intermediate deficiency (<70% G6PD activity), sensitivity fell to a minimum of 64% (95% CI: 52%-75%) and specificity to 35% (95% CI: 24%-46%). Our ability to identify underlying factors associated with study-level heterogeneity was limited by the lack of availability of covariate data and diverse study contexts and methodologies. CONCLUSIONS: Our findings indicate that there is substantial variation in G6PD measurements by spectrophotometry between sites. This is likely due to variability in laboratory methods, with possible contribution of unmeasured population factors. While an assay-specific, universal quantitative threshold offers robust diagnosis at the 30% level, inter-study variability impedes performance of universal thresholds at the 70% level. Caution is advised in comparing findings based on absolute G6PD activity measurements across studies. Novel handheld quantitative G6PD diagnostics may allow greater standardisation in the future.


Assuntos
Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Deficiência de Glucosefosfato Desidrogenase/metabolismo , Glucosefosfato Desidrogenase/metabolismo , Espectrofotometria , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antimaláricos/uso terapêutico , Criança , Pré-Escolar , Feminino , Deficiência de Glucosefosfato Desidrogenase/tratamento farmacológico , Humanos , Lactente , Recém-Nascido , Malária/epidemiologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
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
18.
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
19.
Zhongguo Zhong Yao Za Zhi ; 45(4): 829-837, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32237483

RESUMO

The flower color of Dendrobium catenatum(D. officinale) tends to fade during storage. In order to clarify the influence of storage conditions on the pigment components in flowers, two conditions were applied:temperature and illumination. The contents of pigments in the D. catenatum flower were determined by UV-Vis spectrophotometry and HPLC, and the changes of them during storage were analyzed. The results showed that illumination and temperature had an effect on the pigments of D. catenatum flower during sto-rage. Illumination significantly promoted the degradation of pigments. The contents of total chlorophyll, carotenoids and anthocyanins in the light samples were significantly lower than those in the dark. The total chlorophyll, carotenoids and anthocyanins in the light samples were decreased by 46.5%, 63.4%, and 69.2% respectively. Illumination had a greater effect on fat-soluble pigments than water-soluble pigments. Among the three temperature treatments, the contents of chlorophyll, carotenoid and anthocyanin were as follows:-20 ℃>4 ℃>room temperature, it is indicated that-20 ℃ was the best temperature to maintain the stability of pigment composition. The contents of chlorophyll a, chlorophyll b, ß-carotene, lutein and zeaxanthin in the light samples decreased by 34.8%, 69.0%, 72.5%, 61.6%, 36.1%, respectively. After storage for 5 months, the contents of chlorophyll, carotenoid and anthocyanin constituent at-20 ℃ was significantly higher than those at 4 ℃ and room temperature. The results show that light avoiding and low-temperature can effectively slow down the degradation of pigment components. Therefore, it is suggested that D. catenatum flower should be stored in light avoiding and low-temperature conditions in actual production and processing, which can prolong the usable time.


Assuntos
Dendrobium/química , Armazenamento de Medicamentos , Flores/química , Pigmentos Biológicos/análise , Antocianinas/análise , Carotenoides/análise , Clorofila/análise , Cromatografia Líquida de Alta Pressão , Luz , Plantas Medicinais/química , Espectrofotometria , Temperatura
20.
Food Chem ; 322: 126749, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283371

RESUMO

A simple method combining ultrasound assisted cloud point extraction (UA-CPE) and dispersive µ-solid phase extraction (D-µ-SPE) was developed for preconcentration of As, Cd, Cr, Co, Sb, Pb and Tl to inductively coupled plasma optical emission spectrometric (ICP-OES). At optimum conditions, the linearity, limits of detection and limits of quantification were 0.20-1000 µg L-1, 90-150 ng L-1 and 200-500 ng L-1, respectively. The intraday (n = 20) and intraday (n = 5) precisions reported as the relative standard deviation ranged from 1.5 to 3.5% and 1.9-4.5%. The trueness of the method was investigated using CRM BCR679, NIST SRM 1573a, and SRM 1640a, as well as spiked recovery experiments. Satisfactory recoveries and relative errors ranging from 97 to 99.3% and -4.0 to 2.4% were obtained. The proposed UA-CPE-D-µ-SPE/ICP-OES method was successfully applied for various real samples such as groundwater, bottled mineral water, river water and borehole water and food samples.


Assuntos
Água Doce/análise , Microextração em Fase Sólida/métodos , Espectrofotometria/métodos , Oligoelementos/análise , Verduras/química , Água Potável/análise , Limite de Detecção , Nanotubos de Carbono/química , Sonicação , Oligoelementos/isolamento & purificação , Verduras/metabolismo
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