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1.
J Environ Sci (China) ; 94: 32-39, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32563485

RESUMO

The surface species formed in the reaction of NO and NO2 with pre-adsorbed NH3 over a Fe-ZSM-5 catalyst (1.27 wt.% Fe, SiO2/Al2O3 = 25) at low temperature (140°C) were studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Through using a background spectrum of NH3-saturated Fe-ZSM-5, we clearly observed the formation of common intermediates resulting from the reaction of NO2 or NO + O2 with pre-adsorbed NH3. This presents strong evidence that the oxidation of NO to form surface nitrates and nitrites is the key step for standard SCR at low temperature. In addition, the results suggest that in the SCR reaction at low temperature, the NH4+ ions absorbed on Brønsted acid sites are less active than NH3 adsorbed on Lewis acid sites related to Fe species.


Assuntos
Amônia , Dióxido de Silício , Catálise , Análise de Fourier , Óxido Nítrico , Análise Espectral , Temperatura
2.
Waste Manag ; 113: 51-61, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505975

RESUMO

Much attention has been devoted to disposing traditional-sized poly(methyl methacrylate) (PMMA) waste by pyrolysis for methyl methacrylate (MMA). The pyrolysis of micron-sized PMMA waste, which may be different from that of traditional-sized PMMA waste, received little concern. The present study investigated the kinetics and volatile products of micron-sized PMMA waste pyrolysis in inert atmosphere using thermogravimetry and Fourier transform infrared analysis. A global optimization algorithm namely Shuffled Complex Evolution (SCE) was employed to simultaneously optimize the kinetic parameters. Results indicated that one shoulder and one peak occurred in the MLR variations with temperature. The values of the MLR at the shoulder and peak, the average MLR all increased with the heating rate. The optimized kinetic parameters by SCE can be utilized to well reproduce the experimental thermogravimetric data. The values of activation energy and natural logarithm of pre-exponential factor were in the range of 235.95-248.61 kJ/mol and 16.96-28.76 min-1, respectively. The value of activation energy of micron-sized PMMA waste pyrolysis under the present study was greater than that of the traditional-sized PMMA pyrolysis in the previous studies. MMA and CO2 were the major volatile products generated from the micron-sized PMMA waste pyrolysis. The volatile products yield at peak was much larger than that at shoulder. The MMA and CO2 yield were in the range of 87.98-93.54% and 6.46-12.02%, respectively. High MMA yield may be obtained from the pyrolysis of micron-sized PMMA waste in inert atmosphere by appropriately increasing the heating rate adopted in the reactors in the practical applications.


Assuntos
Polimetil Metacrilato , Pirólise , Análise de Fourier , Cinética , Termogravimetria
3.
PLoS One ; 15(4): e0231087, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32282834

RESUMO

Accurate visual tracking is a challenging issue in computer vision. Correlation filter (CF) based methods are sought in visual tracking based on their efficiency and high performance. Nonetheless, CF-based trackers are sensitive to partial occlusion, which may reduce their overall performance and even lead to failure in tracking challenge. In this paper, we presented a very powerful tracker based on the kernelized correlation filter tracker (KCF). Firstly, we employ an intelligent multi-part tracking algorithm to improve the overall capability of correlation filter based tracker, especially in partial-occlusion challenges. Secondly, to cope with the problem of scale variation, we employ an effective scale adaptive scheme, which divided the target into four patches and computed the scale factor by finding the maximum response position of each patch via kernelized correlation filter. With this method, the scale computation was transformed into locating the centers of the patches. Thirdly, because the small deviation of the central function value will bring the problem of location ambiguity. To solve this problem, the new Gaussian kernel functions are introduced in this paper. Experiments on the default 51 video sequences in Visual Tracker Benchmark demonstrate that our proposed tracker provides significant improvement compared with the state-of-art trackers.


Assuntos
Computadores , Reconhecimento Automatizado de Padrão/métodos , Robótica , Percepção Visual , Algoritmos , Inteligência Artificial , Análise de Fourier , Humanos , Processamento de Imagem Assistida por Computador/métodos , Gravação em Vídeo
4.
Fa Yi Xue Za Zhi ; 36(1): 35-40, 2020 Feb.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-32250076

RESUMO

Abstract: Objective To analyze the differences among electrical damage, burns and abrasions in pig skin using Fourier transform infrared microspectroscopy (FTIR-MSP) combined with machine learning algorithm, to construct three kinds of skin injury determination models and select characteristic markers of electric injuries, in order to provide a new method for skin electric mark identification. Methods Models of electrical damage, burns and abrasions in pig skin were established. Morphological changes of different injuries were examined using traditional HE staining. The FTIR-MSP was used to detect the epidermal cell spectrum. Principal component method and partial least squares method were used to analyze the injury classification. Linear discriminant and support vector machine were used to construct the classification model, and factor loading was used to select the characteristic markers. Results Compared with the control group, the epidermal cells of the electrical damage group, burn group and abrasion group showed polarization, which was more obvious in the electrical damage group and burn group. Different types of damage was distinguished by principal component and partial least squares method. Linear discriminant and support vector machine models could effectively diagnose different damages. The absorption peaks at 2 923 cm-1, 2 854 cm-1, 1 623 cm-1, and 1 535 cm-1 showed significant differences in different injury groups. The peak intensity of electrical injury's 2 923 cm-1 absorption peak was the highest. Conclusion FTIR-MSP combined with machine learning algorithm provides a new technique to diagnose skin electrical damage and identification electrocution.


Assuntos
Algoritmos , Aprendizado de Máquina , Animais , Análise de Fourier , Análise dos Mínimos Quadrados , Suínos
5.
Food Chem ; 320: 126639, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32213423

RESUMO

Laser-induced breakdown spectroscopy (LIBS), Fourier transform mid-infrared (FT-IR) and Raman spectroscopy combined with chemometrics were investigated to quantify calcium (Ca) content in infant formula powder (INF). INF samples (n = 51) with calcium content levels (ca. 6.5-30 mg Ca/100 kJ) were prepared in accordance with the guidelines of Commission Directive 2006/125/EC. Atomic absorption spectroscopy (AAS) was used as the reference method for Ca content determination. To predict Ca content in INF samples, partial least squares regression (PLSR) models that developed based on LIBS, Raman and FT-IR spectral data, respectively. The model developed using LIBS data achieved the best performance for the quantification of Ca content in INF (R2 (cross-validation (CV))-0.99, RMSECV-0.29 mg/g; R2 (prediction (P))-1, RMSEP-0.63 mg/g). PLSR models that developed based on data fusion of Raman and FT-IR spectral features obtained the second best performance (R2CV-0.97, RMSECV-0.38 mg/g; R2P-0.97, RMSEP-0.36 mg/g). This study demonstrated the potential of LIBS, FT-IR and Raman spectroscopy to accurately quantify Ca content in INF.


Assuntos
Cálcio na Dieta/análise , Cálcio/análise , Fórmulas Infantis/química , Análise de Fourier , Humanos , Lactente , Análise dos Mínimos Quadrados , Espectrofotometria Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
6.
PLoS Comput Biol ; 16(3): e1007654, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32176690

RESUMO

The high-resolution and mass accuracy of Fourier transform mass spectrometry (FT-MS) has made it an increasingly popular technique for discerning the composition of soil, plant and aquatic samples containing complex mixtures of proteins, carbohydrates, lipids, lignins, hydrocarbons, phytochemicals and other compounds. Thus, there is a growing demand for informatics tools to analyze FT-MS data that will aid investigators seeking to understand the availability of carbon compounds to biotic and abiotic oxidation and to compare fundamental chemical properties of complex samples across groups. We present ftmsRanalysis, an R package which provides an extensive collection of data formatting and processing, filtering, visualization, and sample and group comparison functionalities. The package provides a suite of plotting methods and enables expedient, flexible and interactive visualization of complex datasets through functions which link to a powerful and interactive visualization user interface, Trelliscope. Example analysis using FT-MS data from a soil microbiology study demonstrates the core functionality of the package and highlights the capabilities for producing interactive visualizations.


Assuntos
Biologia Computacional/métodos , Análise de Fourier , Espectrometria de Massas , Software , Bases de Dados Factuais , Microbiologia do Solo
7.
PLoS One ; 15(3): e0230513, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182266

RESUMO

The aim of the present study was to analyze the time series of team spread during futsal official matches in the frequency domain for different categories. Using an automatic tracking method, trajectories of 258 players (excluding goalkeepers) were obtained, composed of 79 players from the under-15 (U15) category, 86 from the under-18 (U18), and 93 from the professional. We calculated the team spread defined as the Euclidean norm of the distance-between-player vector as a function of time. We applied the Fast Fourier Transformation method and calculated the median frequency for each time series of spread. The results of mean ± SD of the median frequency of the time series of spread from the first to the second half were significantly different only for the U15 category (first half, 1.04 ± 0.46, second half 1.40 ± 0.34). The frequency values differed significantly between the categories. The younger categories presented a higher frequency of spread oscillation than the professional category, which reflects the dynamics of the game between attack and defense sequences. The results provide insights into the features of the sport and present a basis for appropriate training interventions for players in each category, planning for future transition to the following category.


Assuntos
Desempenho Atlético , Análise de Fourier , Humanos , Modelos Teóricos , Futebol , Análise e Desempenho de Tarefas , Estudos de Tempo e Movimento
8.
J Dairy Sci ; 103(4): 3334-3348, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32008779

RESUMO

Fourier transform infrared spectral analysis is a cheap and fast method to predict milk composition. A not very well studied milk component is orotic acid. Orotic acid is an intermediate in the biosynthesis pathway of pyrimidine nucleotides and is an indicator for the metabolic cattle disorder deficiency of uridine monophosphate synthase. The function of orotic acid in milk and its effect on calf health, health of humans consuming milk or milk products, manufacturing properties of milk, and its potential as an indicator trait are largely unknown. The aims of this study were to determine if milk orotic acid can be predicted from infrared milk spectra and to perform a large-scale phenotypic and genetic analysis of infrared-predicted milk orotic acid. An infrared prediction model for orotic acid was built using a training population of 292 Danish Holstein and 299 Danish Jersey cows, and a validation population of 381 Danish Holstein cows. Milk orotic acid concentration was determined with nuclear magnetic resonance spectroscopy. For genetic analysis of infrared orotic acid, 3 study populations were used: 3,210 Danish Holstein cows, 3,360 Danish Jersey cows, and 1,349 Dutch Holstein Friesian cows. Using partial least square regression, a prediction model for orotic acid was built with 18 latent variables. The error of the prediction for the infrared model varied from 1.0 to 3.2 mg/L, and the accuracy varied from 0.68 to 0.86. Heritability of infrared orotic acid predicted with the standardized prediction model was 0.18 for Danish Holstein, 0.09 for Danish Jersey, and 0.37 for Dutch Holstein Friesian. We conclude that milk orotic acid can be predicted with moderate to good accuracy based on infrared milk spectra and that infrared-predicted orotic acid is heritable. The availability of a cheap and fast method to predict milk orotic acid opens up possibilities to study the largely unknown functions of milk orotic acid.


Assuntos
Bovinos/genética , Leite/química , Ácido Orótico/análise , Espectroscopia de Infravermelho com Transformada de Fourier/veterinária , Animais , Bovinos/metabolismo , Indústria de Laticínios , Feminino , Análise de Fourier , Interação Gene-Ambiente , Testes Genéticos , Padrões de Herança , Lactação , Análise dos Mínimos Quadrados , Espectroscopia de Ressonância Magnética , Modelos Genéticos , Fenótipo
9.
Nat Methods ; 17(3): 328-334, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32042190

RESUMO

Cryogenic electron microscopy (cryo-EM) maps are now at the point where resolvability of individual atoms can be achieved. However, resolvability is not necessarily uniform throughout the map. We introduce a quantitative parameter to characterize the resolvability of individual atoms in cryo-EM maps, the map Q-score. Q-scores can be calculated for atoms in proteins, nucleic acids, water, ligands and other solvent atoms, using models fitted to or derived from cryo-EM maps. Q-scores can also be averaged to represent larger features such as entire residues and nucleotides. Averaged over entire models, Q-scores correlate very well with the estimated resolution of cryo-EM maps for both protein and RNA. Assuming the models they are calculated from are well fitted to the map, Q-scores can be used as a measure of resolvability in cryo-EM maps at various scales, from entire macromolecules down to individual atoms. Q-score analysis of multiple cryo-EM maps of the same proteins derived from different laboratories confirms the reproducibility of structural features from side chains down to water and ion atoms.


Assuntos
Apoferritinas/química , Microscopia Crioeletrônica , Algoritmos , Animais , Análise de Fourier , Humanos , Ligação de Hidrogênio , Ligantes , Substâncias Macromoleculares/química , Camundongos , Microscopia Eletrônica , Modelos Moleculares , Distribuição Normal , Estrutura Secundária de Proteína , RNA/química , Solventes/química
10.
Waste Manag ; 103: 378-387, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31954992

RESUMO

Olive pomace, a wet semi-solid paste that remains after olive oil extraction, is a major waste of the process and its recovery is mandatory due to its phytotoxicity when rejected directly into the soil. Innovative applications have been studied, but simple and reliable methods that fulfil the gap between the recovery of compounds and their use by industries (contributing to the sustainability and circular economy of the chain) still need to be explored. In this work, four monocultivar olive pomaces (Arbequina, Arbosana, Oliana, and Koroneiki) were studied regarding their nutritional composition, fatty acids and vitamin E profiles, total phenolic and flavonoid contents, antioxidant activity, and Fourier Transform Near Infrared and Mid Infrared spectra. Principal Component Analysis and Partial Least Square Discriminant Analysis were used to discriminate samples. Arbosana pomace presented the highest total fat (15%, dw) and vitamin E contents (1.4 mg/g of oil), being α-tocopherol the main vitamer in all samples. Koroneiki pomace was the richest in phenolic compounds (9 g gallic acid eq./kg). The major fatty acid was oleic acid. Stearic acid, linoleic acid, and FRAP levels differed significantly among cultivars. NIR spectra showed differences in all spectral regions (best separation from 6504 to 5389 cm-1 and 4961 to 4035 cm-1), while MIR spectra presented differences only in some spectral regions. The results showed that Near Infrared spectroscopy together with Principal Component Analysis is a powerful tool to discriminate olive pomace cultivars, with ability to be used in an industrial context.


Assuntos
Olea , Análise de Fourier , Azeite de Oliva , Espectroscopia de Infravermelho com Transformada de Fourier , Espectroscopia de Luz Próxima ao Infravermelho
11.
Sci Total Environ ; 713: 136573, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955087

RESUMO

Lignin is a highly complex, plant-derived natural biomass component, the analysis of which requires significant demands on the analytical platform. Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) has been shown to be able to readily assess the complexity of lignin and lignin degradation products by assigning tens of thousands of compounds with elemental formulae. Nevertheless, many experimental and instrumental parameters introduce discrimination towards certain components, which limits the comprehensive MS analysis. As a result, a complete characterization of the lignome remains a challenge. The present study investigated a degraded lignin sample using FT-ICR MS and compared several atmospheric pressure ionization methods, e.g., electrospray ionization, atmospheric-pressure chemical ionization, and atmospheric-pressure photoionization. The results clearly show that the number of heteroatoms (e.g., N, S, P) in the sample greatly increases the chemical diversity of lignin, while at the same time also providing potentially useful biomarkers. We demonstrate here that FT-ICR MS was able to directly isolate isotopically pure single components from the ultra-complex mixture for subsequent structural analysis, without the time-consuming chromatographic separation. CAPSULE: Various ionization techniques coupled to FT-ICR MS provide a powerful tool to assess the lignome coverage.


Assuntos
Pressão Atmosférica , Lignina/química , Análise de Fourier , Íons , Espectrometria de Massas
12.
Plant Dis ; 104(3): 847-852, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31940445

RESUMO

Cuticle is the first barrier for rice to resist blast fungus on the surface of the leaf. Studies on how the rice leaf cuticle responds to rice blast and attempts to perform early detection of rice blast are limited, and these two issues were explored in this study via depth-profiling Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). Rice leaves with four different scales of injury (healthy leaves as CK, asymptomatic leaves from mildly diseased seedlings as S1, infected leaves with fewer than five lesions as S2, and infected leaves with more than 10 lesions as S3) were scanned by three moving mirror velocities 0.32, 0.47, and 0.63 cm/s for the depth profiling of the rice leaf surface. The response patterns were acquired via chemometrics to analyze the variations of the chemical group absorptions in the different layers of a sample and in the same layer between different samples. Results showed that the leaf cuticle tended to be thicker and the relative content of fatty alcohols and cutin, unsaturated compounds, and aromatics in the cuticle increased when rice seedlings were infected by blast fungus. Together with the principal component analysis, the probabilistic neural network was applied to identify the samples in early stages (CK and S1), which reached an accuracy of 90% for the samples in the greenhouse and 82% for the samples in the field. Thus, depth-profiling FTIR-PAS was good at analyzing the variation in cuticle layers and showed great potential in the early detection of rice blast or other diseases in different species.


Assuntos
Folhas de Planta , Análise de Fourier , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Doc Ophthalmol ; 140(2): 139-145, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31584130

RESUMO

PURPOSE: To assess the implementation and outcome quality of the Freiburg Acuity VEP methodology (Bach et al. in Br J Ophthalmol 92:396-403, 2008) on the Diagnosys Espion Profile and E3 electrophysiology systems. METHODS: We recorded visual evoked potentials (VEPs) from both eyes of 24 participants, where visual acuity (VA) was either full or reduced with scatter foils to approximately 0.5 and 0.8 LogMAR, resulting in a total of 144 recordings. Behavioral VA was measured in each case under the same conditions using the Freiburg Acuity Test (FrACT); VEP-based acuity was assessed with the "heuristic algorithm," which automatically selects points for regression to zero amplitude. RESULTS: Behavioral VA ranged from - 0.2 to 1.0 LogMAR. The fully automatic heuristic VEP algorithm resulted in 8 of 144 recordings (6%) that were scored as "no result." The other 136 recordings (94%) had an outcome of - 0.20 to 1.3 LogMAR (which corresponds to a range of 20/12.5-20/400, or 6/3.8-6/120, in Snellen ratios; or 1.6-0.1 in decimal acuity). The heuristic VEP algorithm agreed with the behavioral VA to within ± 0.31 LogMAR (95% limits of agreement), which is equivalent to approximately three lines on a VA chart. CONCLUSIONS: The successful implementation of the Freiburg Acuity VEP "heuristic algorithm" on a commercial system makes this capability available to a wider group of users. The limits of agreement of ± 0.31 LogMAR are close to the original implementation at the University of Freiburg and we believe are clinically acceptable for a fully automatic, largely objective assessment of visual acuity.


Assuntos
Eletrofisiologia/instrumentação , Potenciais Evocados Visuais/fisiologia , Transtornos da Visão/fisiopatologia , Acuidade Visual/fisiologia , Adulto , Idoso , Algoritmos , Feminino , Análise de Fourier , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
14.
Doc Ophthalmol ; 140(2): 189-199, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31659575

RESUMO

PURPOSE: To study whether rod- and cone-driven electroretinogram (ERG) responses are altered in myopia patients. METHODS: Dark- and light-adapted ERGs were recorded from 57 myopic eyes of 32 patients aged 22-30 and 19 emmetropic eyes of 10 age-matched normal subjects. The myopic eyes were divided into 3 groups according to spherical equivalent (SE) of manifest refraction: 18 low myopia eyes (≤ - 3.00 diopter (D), 23 moderate myopia eyes (- 3.25 to - 6.00 D), and 16 high myopia eyes (> - 6.25 D). The amplitudes of the dark- and light-adapted ERG a- and b-waves, as well as the frequency spectra of the cone-driven and rod-driven oscillatory potentials (OPs), were analyzed by fast Fourier transform. The peak frequency, implicit time, and total power of the OPs were determined. The axial length was measured with an IOL Master. The ERG parameters including those of the cone- and rod-driven OPs were compared among three groups. RESULTS: The amplitudes of the a-wave and b-wave of the dark-adapted ERGs were increased with refractive power (P < 0.05). Interestingly, the average peak frequency of the rod-driven OPs showed a significant positive correlation with refractive power (P < 0.001): 123.41 ± 9.13 Hz in emmetropic controls, 129.12 ± 10.28 Hz in low myopia, 133.90 ± 9.13 Hz in moderate myopia, and 139.51 ± 5.78 Hz in high myopia. However, the parameters of the light-adapted ERGs and the cone-driven OPs in myopic eyes were within normal ranges. CONCLUSION: We found significant positive correlation between the peak frequency of rod-driven OPs, as well as the amplitudes of rod-driven ERG a- and b-waves, and the refractive power. The results suggest that the rod system function was changing during the progress of myopia, while the cone system function appeared unaffected. The peak frequency of OPs appeared as a novel ERG parameter for myopia, a common ocular condition.


Assuntos
Adaptação à Escuridão/fisiologia , Miopia/fisiopatologia , Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Adulto , Estudos de Coortes , Eletrorretinografia/métodos , Feminino , Análise de Fourier , Humanos , Masculino , Oscilometria , Estimulação Luminosa/métodos , Valores de Referência , Adulto Jovem
15.
Environ Sci Pollut Res Int ; 27(1): 500-509, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31797267

RESUMO

This study investigated the use of a blend of waste vegetable oil and diesel fuel in a diesel tractor engine by comparing the resulting particulate matter (PM) collected on a filter with the PM of diesel fuel. To this purpose, Fourier transform infrared (FTIR) and elemental analyses were carried out and the PM collected on the filters was examined via scanning electron microscopy (SEM). The study also investigated the overall morphology of soot particles from the blend of 75% waste cooking oil (WCO) + 25% diesel (B75) in a diesel engine at three different loads (75%, 50% and 10%) compared with the morphology of the soot particles from diesel fuel (B0). The FTIR spectra of the B75 fuel exhibited the characteristic regions of oxygen bonds. Compared to the B0 fuel, the increased oxidation from the excess oxygen in the B75 fuel reduced the size and number of soot particles. It was also verified that the degree of unsaturation was related to the oxygen content of the B75 fuel. The FTIR spectra of the B75 fuel showed a C = O tensile band methyl ester in 1734 cm-1 and C-O bands at 1214-1362 cm-1. Furthermore, similar FTIR spectra were seen for the diesel fuel (B0) and the B75 fuel. The results showed a significant reduction in soot particle emissions with the WCO-diesel blend. The results of this research have enabled a better evaluation of the effects of different fuel usage on diesel engine combustion performance and emission characteristics.


Assuntos
Material Particulado/química , Óleos Vegetais , Biocombustíveis/análise , Culinária , Análise de Fourier , Gasolina/análise , Material Particulado/análise , Fuligem , Espectroscopia de Infravermelho com Transformada de Fourier , Emissões de Veículos/análise
16.
Talanta ; 208: 120347, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816678

RESUMO

Accurate and effective identification and typing of microorganisms is important in epidemiological surveillance. Fourier transform infrared (FTIR) spectroscopy is a promising bacterial typing method based on extracting the infrared spectrum signal-related biochemical features of intact microbiological cells. Unfortunately, the FTIR signals of bacteria are disturbed by many factors, especially the unavoidable absorbance of H2O, and many studies have focused only on the internal biochemical information. In this study, the interference from water was analyzed and verified by experimental data. The infrared absorbance of H2O overlapped with the protein (1200-1800 cm-1) and lipid regions (2800-3700 cm-1), but had little impact on the polysaccharide and nucleic acid region (900-1200 cm-1). The elimination of the protein and lipid region markedly decreased the interference of H2O and increased the typing accuracy. The results indicate that the polysaccharide and nucleic acid region (900-1200 cm-1) is the only credible region for bacterial typing, and typing based on this region not only reduces the size of the data analysis, but results in more reliable typing results.


Assuntos
Bactérias/classificação , Técnicas de Tipagem Bacteriana/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Água/química , Bactérias/isolamento & purificação , Análise de Fourier , Humanos , Ácidos Nucleicos/química , Polissacarídeos Bacterianos/química
17.
Talanta ; 208: 120439, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816710

RESUMO

Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 T Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.


Assuntos
Proteínas de Bactérias/metabolismo , Técnicas de Tipagem Bacteriana , Proteômica/métodos , Streptomyces/classificação , Streptomyces/metabolismo , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/farmacologia , Análise de Fourier , Pectobacterium/efeitos dos fármacos , Pectobacterium/crescimento & desenvolvimento , RNA Bacteriano , RNA Ribossômico 16S , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Streptomyces/genética , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
18.
PLoS One ; 14(12): e0227207, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31887186

RESUMO

PURPOSE: To describe the retinal contour in optical coherence tomography (OCT) images, and report the relationship between retinal contour and axial length. METHODS: Retinal contour was defined by the path of the retinal pigment epithelial (RPE) line in macular and extra-macular OCTs of 70 eyes of 70 participants recruited from ophthalmology clinics in South Australia. The shape of this contour was described by the best-fit curvature (K), and Fourier analysis of the difference between K and the RPE. The Fourier transformation was summarised by total difference (sumdiff), maximum single frequency difference (MaxE), and root mean square difference (rmse) between each B scan residual and the average normal. All-of-eye and regional median and interquartile range (IQR) shape features were correlated to axial length. RESULTS: Retinal shape irregularity measured by Fourier transformation correlated with axial length: all-of-eye median and IQR sumdiff (ρ = 0.66 and ρ = 0.60 respectively), median and IQR rmse (ρ = 0.67 and ρ = 0.48), median MaxE (ρ = 0.61), and IQR K (ρ = 0.61) all correlated with axial length. Correlation with axial length was also seen in these parameters for 11 of 17 regions. Retinal irregularity was greatest at the macula and in inferior regions. CONCLUSION: Retinal OCT shape becomes increasingly irregular as axial length increases. The range of curvature correlates with axial length, while median curvature does not.


Assuntos
Comprimento Axial do Olho/fisiopatologia , Miopia/diagnóstico , Retina/diagnóstico por imagem , Tomografia de Coerência Óptica , Adulto , Idoso , Idoso de 80 Anos ou mais , Comprimento Axial do Olho/diagnóstico por imagem , Estudos de Viabilidade , Feminino , Análise de Fourier , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Miopia/fisiopatologia , Retina/fisiopatologia , Austrália do Sul
19.
J Am Soc Mass Spectrom ; 30(12): 2692-2703, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31673949

RESUMO

The role of glycosaminoglycans (GAGs) in major biological functions is numerous and diverse, yet structural characterization of them by mass spectrometric techniques proves to be challenging. Characterization of GAG structure from tandem mass spectrometry is a tedious and time-consuming process but one that can be automated in a database-independent, high-throughput fashion through the assistance of software implementing a genetic algorithm (J. Am. Soc. Mass Spectrom. 29, 1802-1911, 2018). This work presents the manner in which this data is interpreted by the software, specifically addressing the development of a scoring algorithm. The significance of glycosidic and cross-ring fragment ions and the implications that specific fragments provide for assigning the positions of modifications are discussed. The scoring algorithm is tested for statistical merit using the widely accepted expectation value as the criterion for quality. Using MS/MS data for well-characterized standards, this scoring approach is shown to assign the correct structure, with a low likelihood (1 in 1012 chances) that the assigned structure matches the data due to random chance. The integrated software that automates the structure assignment is called Glycosaminoglycan-Unambiguous Identification Technology (G-UNIT).


Assuntos
Algoritmos , Glicosaminoglicanos/química , Espectrometria de Massas em Tandem/métodos , Análise de Fourier , Software
20.
Appl Opt ; 58(29): 8031-8038, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31674356

RESUMO

This paper presents an improved autofocus method for human red blood cell images in a microscope. The products of the sum modulus difference and the real-valued fast Fourier transform function are multiplied to obtain an improved sharpness evaluation using the properties of a Gaussian function. It is superior to traditional evaluations in terms of unimodality, steepness, and sensitivity. A new quantitative criterion is proposed to represent the ability of sharpness evaluation against noise. An adaptive focus window with great robustness is proposed that can reduce the computation cost and adverse effects of the background. The better performances of the proposed algorithms are all proved by experiment results, and they can help to find the quasi-focus position more quickly and accurately.


Assuntos
Eritrócitos/química , Aumento da Imagem/métodos , Algoritmos , Simulação por Computador , Análise de Fourier , Humanos , Microscopia , Distribuição Normal
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