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1.
Food Chem ; 303: 125395, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31454758

RESUMO

The multi-isotope calibration (MICal) is a fast and accurate calibration strategy for multi-elemental determination that uses only two solutions, (1) 50% (v v-1) sample plus 50% (v v-1) analytical blank solution, and (2) 50% (v v-1) sample plus 50% (v v-1) standard solution (containing the analytes). The calibration curves were built as a function of the intensity signals of solution 1 (y-axis) versus solution 2 (x-axis), employing the various isotopes of each monitored mass/charge. The concentration of the analytes was calculated from the slope and the concentrations of the standards added to solution 2. The validation of the method was evaluated using standard reference materials of bovine liver and bovine muscle. The recoveries varied from 87 to 113% for MICal, which were similar to the conventional standard additions calibration procedure (83 to 120%).


Assuntos
Espectrometria de Massas/métodos , Carne/análise , Animais , Calibragem , Bovinos , Isótopos , Fígado/química , Produtos da Carne/análise
2.
Water Sci Technol ; 80(3): 517-528, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596263

RESUMO

Selecting a proper spatial resolution for urban rainfall runoff modeling was not a trivial issue because it could affect the model outputs. Recently, the development of remote sensing technology and increasingly available data source had enabled rainfall runoff process to be modeled at detailed and microscales. However, the models with less complexity might have equally good performance with less model establishment and computation time. This study attempted to explore the impact of model spatial resolution on model performance and parameters. Models with different discretization degree were built up on the basis of actual drainage networks, urban parcels and specific land use. The results showed that there was very little difference in the total runoff volumes while peak flows showed obvious scale effects which could be up to 30%. Generally, model calibration could compensate the scale effect. The calibrated models with different resolution showed similar performances. The consideration of effective impervious area (EIA) as a calibration parameter marginally increased performance of the calibration period but also slightly decreased performance in the validation period which indicated the importance of detailed EIA identification.


Assuntos
Hidrologia , Tecnologia de Sensoriamento Remoto , Calibragem , Modelos Teóricos , Chuva , Movimentos da Água
3.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 75(10): 1150-1157, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31631108

RESUMO

In this paper, we proposed an efficient quality assurance method which can measure direct tissue maximum ratio (TMRDir), total scatter factor (Scp, Dir), wedge factor (WFDir), tissue phantom ratio 20/10 (TPR20/10Dir) by using a calibration water phantom and a Farmer chamber. The TMRDir was compared with the calculated TMR (TMRCal) that was calculated from the percentage depth dose at the time of the linear accelerator installation. Scp, Dir, WFDir and TPR20/10Dir calculated from TMRDir were compared with Scp, BD, WFBD, and TPR20/10BD measured at the time of the linear accelerator installation. The difference between TMRDir and TMRCal was approximately within 1% except for using 60° wedge filter. The difference between Scp, Dir and Scp, BD was within 1%, between WFDir and WFBD was within 2%, between TPR20/10Dir and TPR20/10BD was within 1%, these differences were acceptable levels of AAPM TG-142 report. Also, coefficient of variation (CV) of TMRDir, ScpDir, WFDir and TPR20/10Dir when changing days and measuring multiple times were approximately within 1%, these CVs were reference levels of AAPM TG-106 report. We validated that was an efficient quality assurance method by measuring direct tissue maximum ratio, but the propose method has limited in measurable field size.


Assuntos
Aceleradores de Partículas , Água , Calibragem , Imagens de Fantasmas , Radiometria , Dosagem Radioterapêutica
4.
Artigo em Japonês | MEDLINE | ID: mdl-31548467

RESUMO

PURPOSE: Intensity modulated radiation therapy (IMRT) has become a widely accepted and efficient treatment technique for many types of cancers. Patient's specific quality assurance (QA) should be performed with QA devices. Stability and sensitivity tests conducted on the ArcCHECK (AC) 3D diode array were performed. METHODS: Set-up error test with AC was performed. The set-up position moved to lateral (mm), longitudinal (mm) and rotational (°) were 0.5, 1.0, 2.0 and 3.0, respectively. Sensitivity change test of diode array with AC through 230 days was also performed. Same array calibration data was applied to all measurements of volumetric-modulated arc therapy benchmark test through 230 days. Gamma method (2 mm/2% criteria) was performed to analyze the result of all measurements. RESULTS: In the results of positional error, gamma pass rate become degenerate according to positional error became larger. With 0.5 mm or 0.5° positional error, decreasing rate of the pass rate of lateral, longitudinal and rotational were 1.0%, 2.5% and 4.2%, respectively. In the sensitivity change test, the gamma pass rate decreased 2.2%/100 days with same calibration data. CONCLUSION: AC has highly sensitivity against positional error. Sensitivity of AC has been changed and pass rate was decreased 2.2%/100 days through 230 days. Array calibration should be performed in consideration of change of sensitivity.


Assuntos
Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Calibragem , Humanos , Garantia da Qualidade dos Cuidados de Saúde , Radiometria , Dosagem Radioterapêutica
5.
J Chromatogr A ; 1604: 460502, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31492465

RESUMO

Parallel factor analysis 2 (PARAFAC2) is still being advocated for the processing of second-order chromatographic-spectral data, both for qualitative and quantitative applications. However, neither classical PARAFAC2 nor the newly developed flexible non-negative NN-PARAFAC2 version can adequately model these data in a general situation. In quantitative analysis, considerable bias may result in the estimation of analyte concentrations, due to the fact that both PARAFAC2 models apply an artificial constraint to the retrieved profiles, requiring constant cross-product, i.e., constant overlapping, between all pairs of component elution profiles in all samples. This only occurs under limited conditions. In this report, simulations help to understand, visualize and interpret these PARAFAC2 features. Experimental data are also studied concerning the determination of a fluoroquinolone antibiotic in bovine liver samples by liquid chromatography with multi-wavelength fluorescence detection. Both for simulated and experimental data, the PARAFAC2 versions provide poor analytical results, while correct data processing and reasonable analytical indicators can be achieved using multivariate curve resolution - alternating least-squares (MCR-ALS). For the simulated data sets, root mean square errors/relative errors of prediction were 0.01 concentration units/2% for MCR-ALS, compared to 0.02-0.06 units/4-12% for both PARAFAC2 and NN-PARAFAC2. For the experimental data sets, they were 0.025 µg mL-1/11% for MCR-ALS, 0.09 µg mL-1/40% for PARAFAC2 and 0.16 µg mL-1/71% for NN-PARAFAC2, with average recoveries (standard deviation) of 91(14)%, 185(135)% and 69(35)% respectively.


Assuntos
Cromatografia Líquida/métodos , Análise Fatorial , Modelos Teóricos , Animais , Calibragem , Bovinos , Simulação por Computador , Fluorescência , Indicadores e Reagentes , Análise dos Mínimos Quadrados , Análise Multivariada , Reprodutibilidade dos Testes , Soluções
6.
Int J Nanomedicine ; 14: 6869-6889, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507318

RESUMO

Introduction: Biodegradable polymers that contain radioactive isotopes such as Holmium 166 have potential applications as beta particle emitters in tumor tissues. Also, Ho(III) is paramagnetic, which makes it suitable as a contrast agent for magnetic resonance (MR) images. Methods: Holmium acetylacetonate (Ho(acac)3) loaded poly(3-hydroxy-butyrate-co-3-hydroxy-valerate) microspheres, with 5% or 8% of 3-hydroxy-valerate (HV), were prepared by emulsification/evaporation process within 20-53 µm size. Microspheres characterization was done using scanning electron microscopy, energy-dispersive X-ray, and infrared spectroscopies. The release of holmium(III) in sodium phosphate buffer (pH 7.4) was followed for 9 days with inductively coupled plasma. Finally, T2 and T2* magnetic resonance images (MRI) were acquired and compared with the MRI of the inclusion complex of holmium acetylacetonate in some ß-cyclodextrins. Results: Holmium acetylacetonate loading, evaluated by thermogravimetry, was up to 20 times higher for copolymer with 5% of HV. It was shown that microspheres loaded with Ho(acac)3 exhibited an accumulation of Ho(III) on their surfaces but were stable over time, as no expressive release of holmium(III) was detected in 9-day exposition to sodium phosphate buffer. Holmium acetylacetonate in both microspheres or inclusion complexes was very efficient in obtaining T2 and T2* weighted images in magnetic resonance, thus, might be used as contrast agents. Conclusion: This is the first description of the use of inclusion complexes of holmium acetylacetonate in biodegradable polymers as contrast agents. New investigations are underway to evaluate the resistance of PHB-HV polymer microparticles to nuclear activation to assess their potential for use as radiopharmaceuticals for the treatment of liver cancer.


Assuntos
Meios de Contraste/química , Hólmio/química , Hidroxibutiratos/química , Imagem por Ressonância Magnética , Microesferas , Pentanonas/química , Poliésteres/química , Radioisótopos/química , Calibragem , Humanos , Espectrometria por Raios X , Termogravimetria , Difração de Raios X
7.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(4): 664-669, 2019 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-31441269

RESUMO

This study proposed a method to calibrate tube focus spot and the center plane of rotation in computed tomography system. In the method, the tube was rotated to 0° and 180° respectively, and then one metal jig with symmetric windows A and B was scanned at each position under the tube cool and static condition. According to the geometry of tube focus spot, aperture center of the collimator and jig, the distance between tube focus spot and the center plane of rotation were calculated with the X ray transmittance data after denoising, mean value and normalization. To verify the practicability and validity of the method, the tube focus spot in a 16 slices CT system (Brivo CT385, GE, China) was calibrated, and the result after calibration was validated by scanning a polaroid film. The validation result showed that the deviation between tube focal spot and center plane of rotation was 0.02 mm and was in the error range within ± 0.1 mm. The results of this study showed that, as a simple and low-cost design, the method could be used for fast calibration between tube focus spot and the center plane of rotation.


Assuntos
Rotação , Tomografia Computadorizada por Raios X , Calibragem , Raios X
10.
Water Sci Technol ; 79(12): 2260-2270, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31411580

RESUMO

When manually calibrating water quality models, considerable time and attention are required. Hence, developing an automated model that allows for efficient and objective automatic calibration is highly desirable. The QUAL2Kw model calibrates the QUAL2K automatically using a genetic algorithm (GA). This study analyzes auto-calibration results and selects the optimal criterion for each objective function from six performance criteria. Additionally, a multi-objective auto-calibration was conducted using two kinds of performance statistics as the objective function of the GA. The auto-calibration model was applied to the Yeongsan River and the total maximum daily load (TMDL) was established to achieve water quality goals at specific target points of this river. Among the six auto-calibration results based on a single performance criterion, Nash-Sutcliffe model efficiency (NSE) was the best criterion for calculating fitness through auto-calibration. To consider the calibration accuracies of the TMDL target points and the entire river simultaneously, an objective function using multiple performance criteria, specifically the weighted average of the normalized root mean squares error (CV(RMSE)) and the ratio of the RMSE to the standard deviation of the observed data (the RSR), was selected as the final auto-calibration of the model. The model calibration performance was good across the whole region as well as at the target points.


Assuntos
Monitoramento Ambiental , Rios , Calibragem , Modelos Teóricos , Movimentos da Água , Qualidade da Água
11.
J Environ Manage ; 249: 109375, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31408815

RESUMO

River water quality models are often constrained by a lack of understanding of model structures and complicated estimation procedures for unknown parameters. This paper demonstrates a new calibration strategy by setting up a simple model structure for river water quality. The unknown parameters of RWQM were calibrated through the use of small river water quality data sets. In order to facilitate the calibration procedure, data reconstruction and parameter estimation were performed by the systematic application of cubic smoothing spline, polynomial curve-fitting and nonlinear least squares. The quality of calibrated parameters was estimated by developing a sensitivity ranking system. The variation of model outputs showed a slight difference at a sensitivity index of less than 10% and a significant difference at a sensitivity index of more than 50%. The one-way analysis of variance showed a large p-value of 0.8431, indicating that differences between model data and measured data means are not significant. The calibrated model responses and their statistical envelopes were in good agreement with the river water quality data. A MATLAB GUI platform was developed to perform numerical and graphical analysis, which can be used as a relatively simple but robust calibration tool to support model application and data analysis.


Assuntos
Rios , Qualidade da Água , Calibragem , Água Doce , Análise dos Mínimos Quadrados , Modelos Teóricos
12.
Artigo em Japonês | MEDLINE | ID: mdl-31327775

RESUMO

PURPOSE: We conducted a multicenter study to investigate the current status of difference between the actual values at the patient entrance reference point (PERP) and display air kerma. METHODS: We exposure dose and fluoroscopy dose were measured by 32 apparatuses at 32 member institutions of the Japanese Society of Circulation Imaging Technology (CITEC) under unified conditions, and the actual measured values and display air kerma were compared. We entrance doses during fluoroscopy and imaging were measured at the PERP, with focus detector distance (FDD) 110 cm, a copper plate of 3.5 mm in thickness adhered to the front face of flat panel detector (FPD) as absorber, field-of-view (FOV) 18 cm, and the frame rate of 15 f/s, excluding the bed. Display air kerma were recorded at the same time. JIS (Z 4751-2-43: 2012) specify "The reference air kerma rate and the cumulative reference air kerma shall not deviate from their respective display air kerma by more than ±35% over the range of 6 mGy/min and 100 mGy to the maximum value." The number of apparatuses display air kerma deviated from this condition and its percentage were obtained. RESULTS: The mean difference percentage between actual measured values and display air kerma in 32 apparatuses was approximately 15.6%, with some apparatuses showing substantially different display air kerma. CONCLUSION: In order to estimate patients' skin exposure dose from display air kerma more accurately, it is necessary to perform calibration of the apparatus by regular dose measurement or convert values.


Assuntos
Raios X , Calibragem , Fluoroscopia , Humanos , Doses de Radiação , Radiografia , Inquéritos e Questionários
13.
J Chromatogr A ; 1603: 141-149, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31277951

RESUMO

Ethyleneamines have been produced and commercialized for decades in the chemical industry for a diverse range of applications. The presence of amine functional groups provides them opportunity to adsorb onto surfaces which can make them a very challenging sample matrix to analyze using separation techniques. In the present report, a new aqueous SEC-RI method, which enables MWD characterization of higher ethyleneamines, is described. The sample preparation was based on the dilute-and-shoot methodology. A surface-modified SEC column with positively charged groups attached to the stationary phase was used. The mobile phase composition (salt concentration, pH) was optimized to suppress interaction between the ethyleneamines and the packing material. Very symmetrical peak shapes were achieved for low MW monodisperse ethyleneamines despite their high primary amine content. MWD calculations were conducted using conventional narrow standard calibration with partial linear extrapolation of the calibration curve. The narrow standards were of the same chemistry as the samples of interest. Consequently, the standard components display a consistent behaviour towards the column packing as the sample components which makes the present method more robust and the interpretation of the quantitative results more convenient. Effect on the measured MW averages and MW distribution due to various experimental parameters (e.g., system variability, mobile phase preparation, sample concentration) were investigated showing good repeatability (RSD < 2%) for Mn, Mw, and Mz.


Assuntos
Aminas/química , Cromatografia em Gel/métodos , Aminas/síntese química , Calibragem , Peso Molecular , Padrões de Referência , Água/química
14.
J Chromatogr A ; 1603: 262-268, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31257037

RESUMO

A novel application of SPME-GC and UHPLC is presented for the elucidation of an unexplored citrus by-product, namely lemon wax. In view of the current environmental protection strategies, directed toward reuse and/or recovery of waste products, this study aimed to evaluate a possible utilization of a discarded fraction from citrus fruits processing. Headspace SPME coupled with GC-MS and GC-FID allowed determining a residual amount (162.25 mg kg-1) of lemon volatiles, by means of accurate calibration of 38 terpenoids through linear regression analysis (R2 = 0.99). SPME method development, was supported by statistical analysis, consisting of experimental design and multisample comparison, where parameters such as type of coating, temperature and time of fiber exposure, were manipulated towards optimization. The optimized method was validated, showing limits of quantification (LOQ) and of detection (LOD) in the ranges 0.24 - 2.65 ng g-1 and 0.11 - 0.87 ng g-1, respectively; recoveries ranged from 84.9% to 111.5%. After optimization and validation, the UHPLC-PDA method revealed the presence in lemon wax samples of six coumarins, the most abundant being bergamottin (964 mg kg-1), followed, in decreasing amount, by citropten, 8-geranyloxypsoralen, biacangelicin, oxypeucedanin, 5-geranyloxy-7-methoxycoumarin; each analyte was calibrated by external standard methodology. Sensitivity (LOD, 31 - 112 ng g-1; LOQ, 102-370 ng⋅ g-1), accuracy (recovery, 81-94%), and precision (Retention time RSD, 0.03 - 0.09%; peak area RSD, 1.03-2.92%), were also measured.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Citrus/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos Industriais/análise , Microextração em Fase Sólida/métodos , Resíduos/análise , Ceras/análise , Calibragem , Análise Multivariada , Reprodutibilidade dos Testes , Compostos Orgânicos Voláteis/análise
15.
J Chromatogr A ; 1603: 199-207, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31262516

RESUMO

Aryl organophosphate esters (aryl-OPEs) have gained increasing interest over the past few years since a growing number of emerging aryl-OPEs were identified in the environmental media. The currently available analytical methods for aryl-OPEs are usually tailored to detect a very limited number of aryl-OPEs and have inadequate sensitivity for several emerging aryl-OPEs. In this work, a comprehensive and sensitive method for the quantitative analysis of 17 aryl-OPEs in indoor dust samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. The method allows for the determination of four traditional and thirteen emerging aryl-OPEs, which compose almost all the environmentally relevant aryl-OPEs that have been identified. For the first time, 2-isopropylphenyl diphenyl phosphate (2IPPDPP), 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP), bis(2-isopropylphenyl) phenyl phosphate (B2IPPPP), bis(4-tert-butylphenyl) phenyl phosphate (B4tBPPP), and 2-naphthalenyl phosphate (NDPHP) were analyzed using LC-MS/MS. With a systematic optimization of the MS/MS parameters, chromatographic separation conditions, and sample preparation procedures, the target aryl-OPEs in the indoor dust were well separated within 13 min in one analytical run, with limits of quantification ranging from 0.09 to 3.2 ng g-1. Compared with the previously published methods, this method obtained a better sensitivity for most aryl-OPEs. The validated method was applied to 12 indoor dust samples that were collected from residential houses in Guangzhou, China. Both the traditional and emerging aryl-OPEs were frequently detected in the samples, except for NDPHP, with ∑aryl-OPEs ranging from 90 to 33,800 ng g-1. In particular, elevated concentrations of the newly identified tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) were observed in all the indoor dust samples. To our knowledge, these are the first reported data of AO168 = O levels in the environment media from China. These data indicate that AO168 = O is a ubiquitous pollutant that was previously overlooked and merits further investigation in the environment.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Cromatografia Líquida/métodos , Poeira/análise , Ésteres/análise , Organofosfatos/análise , Espectrometria de Massas em Tandem/métodos , Calibragem , China , Solventes
16.
Food Chem ; 300: 125188, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336274

RESUMO

An effective, simple and sensitive analytical method has been developed employing liquid chromatography coupled with tandem mass spectrometry and validated for estimation of five organophosphate pesticides at trace levels in six fruits and twelve vegetables. Plackett-Burman design and central composite design was used to screen and optimize the significant factors in modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. The method evaluation was done by matrix-matched calibration with linearity ranging from 5 to 500 µg/L with a correlation coefficient more than 0.990. The detection and quantification limit ranged from 0.1 to 1.0 µg/kg and 0.5 to 5 µg/kg, respectively. The mean recoveries were in the range of 76.89-110.30 % with the relative standard deviation less than 13.26% for all pesticides. Further, the method developed was applied to analyze real samples cultivated in the hill areas of Nilgiris, South India.


Assuntos
Fracionamento Químico/métodos , Contaminação de Alimentos/análise , Organofosfatos/análise , Praguicidas/análise , Calibragem , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Frutas/química , Índia , Análise Multivariada , Organofosfatos/isolamento & purificação , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Praguicidas/isolamento & purificação , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem/métodos , Verduras/química
17.
J Chromatogr A ; 1602: 386-396, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31285057

RESUMO

A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus providing retention time (tr), m/z and TWCCSN2 values (with the latter compared with the DI-IM-MS data). Analytes for which TWCCSN2 values were obtained by U(H)PLC-IM-MS showed good agreement with the results obtained from DI-IM-MS. The repeatability of the TWCCSN2 values obtained for these metabolites on the different ion mobility QToF systems, using either DI or LC, encouraged the further evaluation of the U(H)PLC-IM-MS approach via the analysis of samples of rat urine, from control and methotrexate-treated animals, in order to assess the potential of the approach for metabolite identification and profiling in metabolic phenotyping studies. Based on the database derived from the standards 63 metabolites were identified in rat urine, using positive ESI, based on the combination of tr, TWCCSN2 and MS data.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Mobilidade Iônica/métodos , Espectrometria de Massas/métodos , Metaboloma , Urina/química , Aminas/análise , Animais , Calibragem , Aprendizado de Máquina , Ratos , Padrões de Referência
18.
BMC Evol Biol ; 19(1): 153, 2019 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340762

RESUMO

BACKGROUND: Evolutionary patterns of scleractinian (stony) corals are difficult to infer given the existence of few diagnostic characters and pervasive phenotypic plasticity. A previous study of Hawaiian Montipora (Scleractinia: Acroporidae) based on five partial mitochondrial and two nuclear genes revealed the existence of a species complex, grouping one of the rarest known species (M. dilatata, which is listed as Endangered by the International Union for Conservation of Nature - IUCN) with widespread corals of very different colony growth forms (M. flabellata and M. cf. turgescens). These previous results could result from a lack of resolution due to a limited number of markers, compositional heterogeneity or reflect biological processes such as incomplete lineage sorting (ILS) or introgression. RESULTS: All 13 mitochondrial protein-coding genes from 55 scleractinians (14 lineages from this study) were used to evaluate if a recent origin of the M. dilatata species complex or rate heterogeneity could be compromising phylogenetic inference. Rate heterogeneity detected in the mitochondrial data set seems to have no significant impacts on the phylogenies but clearly affects age estimates. Dating analyses show different estimations for the speciation of M. dilatata species complex depending on whether taking compositional heterogeneity into account (0.8 [0.05-2.6] Myr) or assuming rate homogeneity (0.4 [0.14-0.75] Myr). Genomic data also provided evidence of introgression among all analysed samples of the complex. RADseq data indicated that M. capitata colour morphs may have a genetic basis. CONCLUSIONS: Despite the volume of data (over 60,000 SNPs), phylogenetic relationships within the M. dilatata species complex remain unresolved most likely due to a recent origin and ongoing introgression. Species delimitation with genomic data is not concordant with the current taxonomy, which does not reflect the true diversity of this group. Nominal species within the complex are either undergoing a speciation process or represent ecomorphs exhibiting phenotypic polymorphisms.


Assuntos
Antozoários/genética , Genoma , Animais , Teorema de Bayes , Calibragem , Genoma Mitocondrial , Hawaii , Funções Verossimilhança , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Fatores de Tempo
19.
Anal Chim Acta ; 1078: 1-7, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358206

RESUMO

The novel laser ablation inductively coupled plasma mass spectrometry methodology for the rapid screening of elemental impurities in solid pharmaceutical samples with the daily dose less than 2.0 g has been developed in accordance with requirements of established USP <232/233> chapters and ICH-Q3D guideline. The LA-ICP-MS methodology covering the determination of Cd, Pb, As, Hg, Co, V, Ni, Tl, Au, Pd, Ir, Os, Rh, Ru, Se, Ag, Pt was successfully validated in terms of linearity, limit of quantification, accuracy, precision, intermediate precision, specificity and range. Moreover, the presented 'in-house' matrix-matched standards preparation methodology helps to overcome crucial analytical problem connected with unavailability of commercial certified matrix-matched reference material suitable for the direct elemental impurities analysis in various kinds of solid pharmaceutical products. A two step homogeneity study of prepared matrix-matched calibration standards is also reported to investigate the homogeneity of distribution of elemental impurities and internal standards across the pressed pellet. The validated LA-ICP-MS method was applied on analysis of several types of solid pharmaceutical samples (active pharmaceutical ingredients, excipients, placebo and final drug products). The proposed method allowed the accurate, precise and fast screening of elemental impurities without necessity of time and labour consuming solutions preparation and thus it can be used in routine practice as an alternative to conventional ICP-MS or ICP-OES for the rapid quality control of different stages of pharmaceutical production.


Assuntos
Espectrometria de Massas/métodos , Metais Pesados/análise , Preparações Farmacêuticas/análise , Calibragem , Contaminação de Medicamentos , Espectrometria de Massas/normas , Padrões de Referência , Selênio/análise
20.
Anal Chim Acta ; 1078: 24-31, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358225

RESUMO

A novel electrochemical DNA biosensor was developed and MON89788 of soybean transgenic gene sequence was detected based on a strategy of rolling circle amplification (RCA) and gold nanoparticle cube (AuNPC)-labeled multiple probes. First, the mercapto-modified capture DNA was immobilized on the surface of the Fe3O4@Au magnetic nanoparticles via an Au-S bond, and the capture DNA was opened and complementarily hybridized with the target DNA to form a double-stranded DNA. In the 10 × reaction buffer, Exonuclease III (ExoIII) specifically recognized and sheared the double-stranded DNA to release the target DNA, which led to the next round of reaction. Afterward, AuNP cube-loaded ssDNA (AuNPC/DNA) was added with the rolling circle reaction with the help of Phi29 DNA polymerase and T4 ligase. Finally, [Ru(NH3)6]3+ was attracted directly by the anionic phosphate of ssDNA via electrostatic interaction. The determination was carried out by using chronocoulometry (CC), and the CC signal was recorded. The mass amount of DNA strands extended infinitely on the AuNPs cube and numerous [Ru(NH3)6]3+ were absorbed, thus the detected signal was highly amplified. The corresponding CC signal showed a good linear relationship with the logarithm of the target DNA concentration in the range of 1 × 10-16 to 1 × 10-7 mol L-1, with a detection limit of 4.5 × 10-17 mol L-1. Specific gene sequence of MON89788 in soybean samples was determined, and the recoveries ranged from 97.3% to 102.0%. This sensor is one of the most sensitive sensors for genetic sequence assessment at present. Moreover, it demonstrates good selectivity, stability, and reproducibility.


Assuntos
Técnicas Biossensoriais/métodos , DNA de Plantas/análise , Técnicas Eletroquímicas/métodos , Plantas Geneticamente Modificadas/genética , Soja/genética , Sequência de Bases , Calibragem , Sondas de DNA/química , Sondas de DNA/genética , DNA de Plantas/química , DNA de Plantas/genética , Exodesoxirribonucleases/química , Ouro/química , Limite de Detecção , Nanopartículas de Magnetita/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Oligodesoxirribonucleotídeos/genética , Reprodutibilidade dos Testes , Compostos de Rutênio/química
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