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1.
PLoS One ; 15(2): e0223934, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32109248

RESUMO

Biomass is an important indicator for monitoring vegetation degradation and productivity. This study tests the applicability of Hyperspectral Remote-Sensing in situ measurements for high-precision estimation aboveground biomass (AGB) on regional scales of Khorchin grassland in Inner Mongolia, China. In order to improve prediction accuracy of AGB which is frequently used as an indicator of aboveground net primary productivity (ANPP), this paper combined ground measurement with remote sensing inversion to build the spectral model. The ground normalized difference vegetation index (SOC_NDVI) calculated from ground spectral of grassland vegetation which was measured by a portable visible/NIR hyperspectral spectrometer (SOC 710). Meanwhile, the remote normalized difference vegetation index (TM_NDVI) calculated from remote spectral of grassland vegetation which was measured by Thematic Mapper (TM) from Landsat 8 which launched by National Aeronautics and Space Administration (NASA). According to regression analysis for the relationship between AGB and SOC_NDVI, SOC_NDVI and TM_NDVI, the evaluation model for aboveground biomass was developed (AGB = 12.523×e3.370×(0.462×TM_NDVI+0.413), standard error = 24.74 g m-2, R2 = 0.636, p < 0.001). The model accuracy verification results show that the correlation between the measured value and the predicted value of biomass was better with low model standard error. The model could make up for the lack of timeliness and comprehensiveness of conventional ground biomass survey, and provide technical support for high-precision large-area productivity estimation and ecological degradation diagnosis of regional scale grassland.


Assuntos
Biomassa , Pradaria , Tecnologia de Sensoriamento Remoto/métodos , China , Ecologia/métodos , Tecnologia de Sensoriamento Remoto/instrumentação , Reprodutibilidade dos Testes , Análise Espectral/instrumentação
2.
Anal Chim Acta ; 1093: 150-159, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31735208

RESUMO

As a powerful tool for medical diagnosis and bioanalysis, conventional optical spectrometers are generally expensive, bulky and always require an accompanying data processing device. In this work, we developed a novel smartphone-based CD-spectrometer (SCDS) for high sensitive and ultra-portable colorimetric analysis, with the advantage of cost-effective and simplicity. The distance between the light source and slit, the structure of SCDS and the parameters of camera in the smartphone were all optimized to ensure the best analytical performance. Besides, the SCDS employed HSV color model and utilized the overall intensity calculated by summing V-value of adjacent position for the absorbance measurement. In this way the errors caused by the low resolution of CD-grating can effectively be eliminated to promote the sensitivity of the SCDS. The performance of the SCDS was first validated for colorimetric detection of BSA with a detection limit of 0.0073 mg/mL, which is superior compared to that of the microtiter plate reader (MTPR). Moreover, by combining with 3,3',5,5'-tetramethylbenzidine-manganese dioxide (TMB-MnO2) nanosheets reaction, a high sensitive and specific system for ascorbic acid detection was established. The SCDS gives a detection range from 0.6250 µM to 40 µM with a detection limit of 0.4946 µM for AA detection. Compared to other studies, the SCDS features wide detection range and very low detection limit with low cost instrument. Therefore, the SCDS will be an ideal and promising colorimetric system for point-of-care (POC) application in food security, disease diagnosis and environmental monitoring.


Assuntos
Ácido Ascórbico/análise , Colorimetria/métodos , Discos Compactos , Smartphone , Análise Espectral/métodos , Animais , Benzidinas/química , Bebidas/análise , Bovinos , Colorimetria/instrumentação , Desenho de Equipamento , Limite de Detecção , Compostos de Manganês/química , Nanoestruturas/química , Óxidos/química , Testes Imediatos , Soroalbumina Bovina/análise , Análise Espectral/instrumentação
3.
Food Chem Toxicol ; 136: 111081, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31883987

RESUMO

Mycotoxins are toxic compounds produced by the metabolism of certain fungi that threaten the food and agricultural industry. Over hundreds of mycotoxins, one of the most common toxins, zearalenone (ZEN), has toxic effects on human and animal health due to its mutagenicity, treatogenicity, carcinogenicity, nephrotoxicity, immunotoxicity, and genotoxicity. In this work, attenuated internal reflection spectroscopic ellipsometry (AIR-SE) combined with the signal amplification via surface plasmon resonance conditions that were proved to be a highly sensitive analytical tool in bio-sensing was developed for the sensitive and selective ZEN detection in cereal products such as corn, wheat, rice, and oat. Combined with the oligonucleotide aptamer for ZEN recognition, our proposed method showed good performance with yielding 0.08 ng/mL LOD and 0.01-1000 ng/mL detection range. A mini-review was also introduced in, to compare various methods for ZEN detection.


Assuntos
Grão Comestível/química , Contaminação de Alimentos/análise , Análise Espectral/métodos , Zearalenona/análise , Aptâmeros de Nucleotídeos/análise , Oryza/química , Análise Espectral/instrumentação , Triticum/química , Zea mays/química
4.
Anal Bioanal Chem ; 411(29): 7737-7745, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31713014

RESUMO

A newly developed molecularly imprinted photonic polymer (MIPP) film, which was prepared by colloidal crystal templating and surface molecular imprinting, was used for selective capture of S-layer protein (SLP) from a complex Lactobacillus acidophilus sample. The colloidal crystal templates were formed by a dipping process followed by chemical binding of the imprinted template SLP molecules. A sandwich structure consisting of two glass slides was formed after the SLP-silica layer had been covered with a poly(methyl methacrylate) glass slide. After polymerization of the SLP-silica layer with the preprepared polymerization solution, hydrofluoric acid and acetic phosphate buffer solutions removed the silica particles and SLP molecules, respectively. The MIPP film obtained exhibited a three-dimensional, highly ordered and interconnected macroporous structure (pore size greater than 200 nm), which is specifically accessible to SLP molecules. The adsorbed SLP molecules were simply and straightforwardly detected by a fiber-optic spectrometer. The redshift of the Bragg diffraction peak of the MIPP film was linearly related to the number of SLP molecules that had been harvested in the film. The detection limit of the SLP-MMIP-fiber-optic spectrometer method for SLP was 1 ng mL-1. The MIPP sensor was successfully applied to detect SLP molecules in a crudely extracted Lactobacillus acidophilus sample. Our results prove the applicability of the SLP-MIPP film for fast and real-time measurement of SLP. Graphical abstract.


Assuntos
Proteínas de Bactérias/análise , Tecnologia de Fibra Óptica , Glicoproteínas de Membrana/análise , Impressão Molecular , Fótons , Polímeros/química , Análise Espectral/instrumentação , Lactobacillus acidophilus/química , Limite de Detecção
5.
PLoS One ; 14(11): e0224492, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31765375

RESUMO

INTRODUCTION: Microfluidic reactionware allows small volumes of reagents to be utilized for highly controlled flow chemistry applications. By integrating these microreactors with onboard analytical systems, the devices change from passive ones to active ones, increasing their functionality and usefulness. A pressing application for these active microreactors is the monitoring of reaction progress and intermediaries with respect to time, shedding light on important information about these real-time synthetic processes. OBJECTIVE: In this multi-disciplinary study the objective was to utilise advanced digital fabrication to research metallic, active microreactors with integrated fibre optics for reaction progress monitoring of solvent based liquids, incompatible with previously researched polymer devices, in combination with on-board Ultraviolet-visible spectroscopy for real-time reaction monitoring. METHOD: A solid-state, metal-based additive manufactured system (Ultrasonic Additive Manufacturing) combined with focussed ion beam milling, that permitted the accurate embedment of delicate sensory elements directly at the point of need within aluminium layers, was researched as a method to create active, metallic, flow reactors with on-board sensing. This outcome was then used to characterise and correctly identify concentrations of UV-active water-soluble B-vitamin nicotinamide and fluorescein. A dilution series was formed from 0.01-1.75 mM; which was pumped through the research device and monitored using UV-vis spectroscopy. RESULTS: The results uniquely showed the in-situ ion milling of ultrasonically embedded optical fibres resulted in a metallic microfluidic reaction and monitoring device capable of measuring solvent solutions from 18 µM to 18 mM of nicotinamide and fluorescein, in real time. This level of accuracy highlights that the researched device and methods are capable of real-time spectrographic analysis of a range of chemical reactions outside of those possible with polymer devices.


Assuntos
Técnicas de Química Sintética/métodos , Técnicas Analíticas Microfluídicas/métodos , Análise Espectral/métodos , Alumínio/química , Técnicas de Química Sintética/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Fibras Ópticas , Solventes/química , Análise Espectral/instrumentação , Fatores de Tempo , Ondas Ultrassônicas
6.
Sensors (Basel) ; 19(22)2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31739635

RESUMO

Dental enamel constitutes the outer layer of a crown of teeth and grows nearly parallel. This unique nanostructure makes enamel possess birefringence properties. Currently, there is still no appropriate clinical solution to examine dental hard tissue diseases. Therefore, we developed an optical polarization imaging system for diagnosing dental calculus, caries, and cracked tooth syndrome. By obtaining Stokes signals reflected from samples, Mueller images were constructed and analyzed using Lu-Chipman decomposition. The results showed that diattenuation and linear retardance images can distinguish abnormal tissues. Our result also aligns with previous studies assessed by other methods. Polarimetric imaging is promising for real-time diagnosing.


Assuntos
Esmalte Dentário/diagnóstico por imagem , Análise Espectral/instrumentação , Doenças Estomatognáticas/diagnóstico , Dente/diagnóstico por imagem , Esmalte Dentário/fisiopatologia , Humanos , Nanoestruturas/química , Fenômenos Ópticos , Doenças Estomatognáticas/fisiopatologia
7.
Sensors (Basel) ; 19(22)2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31698709

RESUMO

Whole-body bioelectrical impedance analysis for measuring body composition has been well-explored but may not be sensitive enough to changes in the trunk compared to changes in the limbs. Measuring individual body segments can address this issue. A segmental bioelectrical impedance spectroscopy device (SBISD) was designed for body composition measurement and a prototype was implemented. Compensation was performed to adjust the measured values to correct for a phase difference at high frequencies and to counteract the hook effect when measuring the human body. The SBISD was used to measure five subjects and was compared against three existing analyzers. For most segmental measurements, the SBISD was within 10% of the R0 and R∞ values determined with a Bodystat Multiscan 5000 and an Impedimed SFB7. The impedance values from the third reference device, a Seca 514, differed significantly due to its eight-electrode measuring technique, meaning impedance measurements could not be compared directly.


Assuntos
Composição Corporal/fisiologia , Análise Espectral/instrumentação , Impedância Elétrica , Eletrodos , Humanos
8.
Molecules ; 24(15)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382495

RESUMO

Single molecule fluorescence spectroscopy has been largely implemented using methods which require tethering of molecules to a substrate in order to make high temporal resolution measurements. However, the act of tethering a molecule requires that the molecule be removed from its environment. This is especially perturbative when measuring biomolecules such as enzymes, which may rely on the non-equilibrium and crowded cellular environment for normal function. A method which may be able to un-tether single molecule fluorescence spectroscopy is real-time 3D single particle tracking (RT-3D-SPT). RT-3D-SPT uses active feedback to effectively lock-on to freely diffusing particles so they can be measured continuously with up to photon-limited temporal resolution over large axial ranges. This review gives an overview of the various active feedback 3D single particle tracking methods, highlighting specialized detection and excitation schemes which enable high-speed real-time tracking. Furthermore, the combination of these active feedback methods with simultaneous live-cell imaging is discussed. Finally, the successes in real-time 3D single molecule tracking (RT-3D-SMT) thus far and the roadmap going forward for this promising family of techniques are discussed.


Assuntos
Técnicas Biossensoriais , Imageamento Tridimensional , Imagem Individual de Molécula , Análise Espectral , Animais , Linhagem Celular , Humanos , Soluções , Análise Espectral/instrumentação , Análise Espectral/métodos
10.
Biosens Bioelectron ; 142: 111508, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325675

RESUMO

Incorporation of new readout methods with established analytical devices allows methodological innovations in analytical sciences. Herein, we present a new sensing platform by combining an ultrasensitive element analyzer, namely the laser-induced breakdown spectroscopy (LIBS) and a lateral flow strip (LFS). AgxAuy bimetallic nanoparticles (AgxAuyBNPs) are selected as the labels to deliver the optimal quantitative performance by analyzing the Ag (I) signal from the test (T) line of LFS. For prototypical application in pathogen detection, the LIBS-LFS sensor can achieve a detection limit of 1.6 cfu mL-1 of Staphylococcus aureus (S. aureus) within 10 min, which is superior to conventional methods. Importantly, the signals of AgxAuyBNPs for visual and LIBS analysis are stable and still readable after the detection is finished and the test strip is stored for up to 13 days, suggesting a potential for long-term data preservation. This combination of LIBS with LFS provides a new concept toward integrated nano/analytical devices that can benefit various application scenarios.


Assuntos
Técnicas Biossensoriais/instrumentação , Nanopartículas Metálicas/química , Fitas Reagentes/análise , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Animais , Técnicas Biossensoriais/economia , Água Potável/microbiologia , Desenho de Equipamento , Análise de Alimentos/economia , Análise de Alimentos/instrumentação , Microbiologia de Alimentos , Ouro/química , Humanos , Lasers , Limite de Detecção , Leite/microbiologia , Fitas Reagentes/economia , Prata/química , Análise Espectral/economia , Análise Espectral/instrumentação , Infecções Estafilocócicas/diagnóstico
11.
Methods Mol Biol ; 2027: 181-194, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31309482

RESUMO

The procedures for response standardization in "electronic tongue" (ET) studies are described. The construction of reliable multivariate calibration for "electronic tongue" requires the analysis of a large number of representative samples both with ET and reference techniques. This is a laborious and expensive process. Long-term sensor array operation leads to the changes in sensor response characteristics and thus invalidates the multivariate predictive models. Moreover, due to the individual parameters of each sensor in different sensor arrays, it is not possible to use the calibration model for one system together with the data acquired by another system, even if they have the same sensors. Both of these issues lead to the necessity of frequent sensor array calibration which would be ideal to avoid. Instead of recalibration, these two problems can be handled using mathematical methods intended for sensor response standardization. This chapter describes two popular methods of standardization which can be used for both drift correction and calibration transfer. Thus, significant efforts on measuring representative sample sets for sensor array recalibration can be avoided.


Assuntos
Nariz Eletrônico/normas , Modelos Químicos , Calibragem , Potenciometria/instrumentação , Potenciometria/métodos , Potenciometria/normas , Padrões de Referência , Análise Espectral/instrumentação , Análise Espectral/métodos , Análise Espectral/normas
12.
Opt Express ; 27(13): 17940-17953, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31252745

RESUMO

A sensitive high-resolution sub-Doppler detecting spectrometer, based on noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS), for trace gas detection of species whose transitions have severe spectral overlap with abundant concomitant species is presented. It is designed around a NICE-OHMS instrumentation utilizing balanced detection that provides shot-noise limited Doppler-broadened (Db) detection. By synchronous dithering the positions of the two cavity mirrors, the effect of residual etalons between the cavity and other surfaces in the system could be reduced. An Allan deviation of the absorption coefficient of 2.2 × 10-13 cm-1 at 60 s, which, for the targeted transition in C2H2, corresponds to a 3σ detection sensitivity of 130 ppt, is demonstrated. It is shown that despite significant spectral interference from CO2 at the targeted transition, which precludes Db detection of C2H2, acetylene could be detected in exhaled breath of healthy smokers.


Assuntos
Acetileno/análise , Testes Respiratórios/instrumentação , Efeito Doppler , Gases/análise , Ruído , Fenômenos Ópticos , Análise Espectral/instrumentação , Simulação por Computador , Humanos , Processamento de Sinais Assistido por Computador , Fumar
13.
Analyst ; 144(14): 4380-4385, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31206108

RESUMO

We report a smartphone based multispectral imager (MSI), a promising tool for point-of-care (POC) testing, which utilizes a bio-inspired MSI chip to capture both the spectral and spatial information of a target simultaneously. As the key component for compact MSI, the proposed MSI chip mimics the structure of an insect compound-eye, wherein each sub-eye responds to a specific spectral band. This could allow a smartphone to be transformed into an MSI device that could acquire a snap-shot spectral image in a single exposure. An orthogonal polarization imaging method is adopted, to boost the capability of the smartphone MSI for chemical analysis. The feasibility and application potential of the proposed device are demonstrated non-invasively for skin lesion and dental plaque analysis. The experimental results are consistent with the physiological expectations, validating the ability of the smartphone MSI for multispectral image acquisition and further analytical determination. The chemical analysis capability, portability and cost-effectiveness of the smartphone MSI make it a promising analytical tool for POC testing, from chemical analysis to in vivo pathological diagnosis.


Assuntos
Dispositivos Ópticos , Smartphone , Análise Espectral/instrumentação , Adulto , Placa Dentária/diagnóstico por imagem , Humanos , Masculino , Nevo/diagnóstico por imagem , Testes Imediatos , Análise Espectral/métodos
14.
Food Chem ; 295: 36-41, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174769

RESUMO

TOB aptamer can be adsorbed on the AuNPs surface to form AuNPs-aptamer complexation to prevent AuNPs aggregation in high salt solution. When TOB was added to the AuNPs solution, the aptamer would bind with TOB and depart from the AuNPs surface. The amount of the AuNPs-aptamer complexation depends on the TOB concentration. Different concentration of AuNPs-aptamer can catalyze the reduction reaction of CuSO4 to produce different size Cu2O particle. The resonance scattering peak intensities are correlated with the Cu2O size. Large size Cu2O particle as a resonance scattering spectroscopy probe can remarkable improve the TOB detection sensitivity. We have succeeded to detect the trace TOB in aqueous solutions. The linear range and limit of detection were 0.50-17 nM and 0.19 nM, respectively. This simple and inexpensive method exhibited high sensitivity and selectivity, which was successfully used to detect TOB in milk. The results indicated the accuracy and precision were satisfied.


Assuntos
Aptâmeros de Nucleotídeos/química , Análise de Alimentos/métodos , Leite/química , Análise Espectral/métodos , Tobramicina/análise , Adsorção , Animais , Técnicas Biossensoriais/métodos , Catálise , Sulfato de Cobre/química , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Pasteurização , Sensibilidade e Especificidade , Análise Espectral/instrumentação
15.
Nutr. hosp ; 36(3): 618-625, mayo-jun. 2019. tab, graf
Artigo em Inglês | IBECS | ID: ibc-184560

RESUMO

Introduction: recently there have been several new versions of equipment based on the principles of bioelectrical impedance (BIA). Therefore, it is important to know the agreement between data produced by different commercially available equipment. Objective: to verify the agreement between fat-free mass (FFM), fat mass (FM), and body fat percentage (BF%) estimated using different segmental multi-frequency BIA (Tanita(R) MC-980U and InBody 770(R)) and whole-body spectral techniques (Xitron 4200). Methods: the sample consisted of 117 adults of both sexes, aged between 18 and 28 years. Methodological procedures followed specific guidelines for each equipment model. Agreement was analyzed by the t-test for paired data, concordance correlation coefficient (CCC), and Bland-Altman plot. Results: mean estimates of FFM, FM, and BF% produced by the Tanita(R) MC-980U and InBody 770(R) devices did not present statistical differences compared to the Xitron 4200(R) reference device. CCC values for FFM demonstrated magnitudes between 0.904 and 0.931, representing clinically acceptable strength of agreement, while for FM and BF% the strength of agreements was weak (< 0.90). Regarding the FFM, the bias showed underestimates of -0.98 kg to -1.69 kg, with limits of agreement between -7.32 kg and 3.94 kg. In the case of FM and BF%, overestimations were observed that reached values of 1.01 kg and 0.71%, with limits of agreement of -1.91 kg to 3.93 kg and -3.86% to 5.28%, respectively. Conclusion: FFM, FM, and BF% estimated by the Tanita(R) MC-980U and InBody 770(R) devices were not individually comparable with estimates produced by the Xitron 4200(R) reference device; therefore, its replacement for diagnostic purposes and inter- or intra-subject comparisons is not recommended


Introducción: recientemente han surgido varias versiones de equipamiento que se basan en los principios de bioimpedancia eléctrica (BIA). Por lo tanto, es importante conocer la concordancia entre datos producidos por diferentes equipamientos disponibles comercialmente. Objetivos: verificar la concordancia entre masa libre de grasa (MLG), masa grasa (MG) y porcentaje de grasa (%Grasa) estimadas por diferentes equipamientos de BIA por técnica segmentar de multifrecuencia (Tanita(R) MC-980U e InBody 770(R)) y espectral de cuerpo entero (Xitron 4200(R)). Métodos: muestra constituida por 117 adultos de ambos sexos con edad entre 18 y 28 años. Los procedimientos metodológicos han seguido las directrices específicas de cada modelo de equipamiento. La concordancia se analizó mediante el test t para datos pareados, coeficiente de correlación de concordancia (CCC) y trazado Bland-Altman. Resultados: las estimaciones medias de MLG, MG y %Grasa producidas por los equipamientos Tanita(R) MC-980U e InBody 770(R) no presentaron diferencias estadísticas en comparación con el equipamiento de referencia Xitron 4200(R). Los valores de CCC para MLG presentaron magnitudes entre 0,904 y 0,931, lo que representa una fuerza de concordancia clínicamente aceptable, mientras que para MG y %Grasa la fuerza de concordancia fue débil (< 0,90). Con respecto al MLG, los sesgos apuntaron subestimaciones de -0,98 kg a -1,69 kg, con límites de concordancia entre -7,32 kg y 3,94 kg. En el caso de la MG y del %Grasa, se observaron sobreestimaciones que alcanzaron valores de 1,01 kg y 0,71%, con límites de concordancia de -1,91 kg a 3,93 kg y -3,86% a 5,28%, respectivamente. Conclusión: la MLG, la MG y el %Grasa estimados por los equipamientos Tanita(R) MC-980U e InBody 770(R) no fueron comparables individualmente con estimaciones producidas por el equipamiento de referencia Xitron 4200(R). Por lo tanto, no se aconseja su sustitución para efecto de diagnóstico y comparaciones inter o intraindividuos


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Impedância Elétrica , Composição Corporal , Análise Espectral/instrumentação , Índice de Massa Corporal , Peso Corporal , Brasil , Estudantes/estatística & dados numéricos
16.
Nat Commun ; 10(1): 2250, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113945

RESUMO

Recent progress has been made in paleontology with respect to resolving pigmentation in fossil material. Morphological identification of fossilized melanosomes has been one approach, while a second methodology using chemical imaging and spectroscopy has also provided critical information particularly concerning eumelanin (black pigment) residue. In this work we develop the chemical imaging methodology to show that organosulfur-Zn complexes are indicators of pheomelanin (red pigment) in extant and fossil soft tissue and that the mapping of these residual biochemical compounds can be used to restore melanin pigment distribution in a 3 million year old extinct mammal species (Apodemus atavus). Synchotron Rapid Scanning X-ray Fluorescence imaging showed that the distributions of Zn and organic S are correlated within this fossil fur just as in pheomelanin-rich modern integument. Furthermore, Zn coordination chemistry within this fossil fur is closely comparable to that determined from pheomelanin-rich fur and hair standards. The non-destructive methods presented here provide a protocol for detecting residual pheomelanin in precious specimens.


Assuntos
Extinção Biológica , Fósseis , Melaninas/análise , Animais , Cabelo/química , Melaninas/química , Murinae , Imagem Óptica/instrumentação , Imagem Óptica/métodos , Paleontologia/métodos , Análise Espectral/instrumentação , Análise Espectral/métodos , Enxofre/química , Zinco/química
17.
Arch Dis Child Fetal Neonatal Ed ; 104(6): F648-F653, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31085677

RESUMO

OBJECTIVES: A new device that combines, for the first time, two photonic technologies (time-resolved near-infrared spectroscopy and diffuse correlation spectroscopy) was provided and tested within the BabyLux project. Aim was to validate the expected changes in cerebral oxygenation and blood flow. METHODS: A pulse oximeter and the BabyLux device were held in place (right hand/wrist and frontoparietal region, respectively) for 10 min after birth in healthy term infants delivered by elective caesarean section. Pulse oximeter saturation (SpO2), cerebral tissue oxygen saturation (StO2) and blood flow index (BFI) were measured over time. Tissue oxygen extraction (TOE) and cerebral metabolic rate of oxygen index (CMRO2I) were calculated. RESULTS: Thirty infants were enrolled in two centres. After validity check of data, 23% of infants were excluded from TOE and CMRO2I calculation due to missing data. As expected, SpO2 (estimate 3.05 %/min; 95% CI 2.78 to 3.31 %/min) and StO2 (estimate 3.95 %/min; 95% CI 3.63 to 4.27 %/min) increased in the first 10 min after birth, whereas BFI (estimate -2.84×10-9 cm2/s/min; 95% CI -2.50×10-9 to -3.24×10-9 cm2/s/min) and TOE (estimate -0.78 %/min; 95% CI -1.12 to -0.45 %/min) decreased. Surprisingly, CMRO2I decreased (estimate -7.94×10-8/min; 95% CI -6.26×10-8 to -9.62×10-8/min). CONCLUSIONS: Brain oxygenation and BFI during transition were successfully and simultaneously obtained by the BabyLux device; no adverse effects were recorded, and the BabyLux device did not limit the standard care. The preliminary results from clinical application of the BabyLux device are encouraging in terms of safety and feasibility; they are consistent with previous reports on brain oxygenation during transition, although the interpretation of the decreasing CMRO2I remains open. TRIAL REGISTRATION NUMBER: NCT02815618.


Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Oxigênio/sangue , Análise Espectral/instrumentação , Encéfalo/metabolismo , Cesárea , Feminino , Hemodinâmica , Humanos , Recém-Nascido , Masculino , Oximetria , Espectroscopia de Luz Próxima ao Infravermelho
18.
Faraday Discuss ; 217: 8-33, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31094388

RESUMO

This introduction provides a historical context for the development of ion spectroscopy over the past half century by following the evolution of experimental methods to the present state-of-the-art. Rather than attempt a comprehensive review, we focus on how early work on small ions, carried out with fluorescence, direct absorption, and photoelectron spectroscopy, evolved into powerful technologies that can now address complex chemical problems ranging from catalysis to biophysics. One of these developments is the incorporation of cooling and temperature control to enable the general application of "messenger tagging" vibrational spectroscopy, first carried out using ionized supersonic jets and then with buffer gas cooling in radiofrequency ion traps. Some key advances in the application of time-resolved pump-probe techniques to follow ultrafast dynamics are also discussed, as are significant benchmarks in the refinement of ion mobility to allow spectroscopic investigation of large biopolymers with well-defined shapes. We close with a few remarks on challenges and opportunities to explore molecular level mechanics that drive macroscopic behavior.


Assuntos
Fenômenos Astronômicos , Biopolímeros/análise , Física , Análise Espectral/tendências , Biologia , Análise Espectral/instrumentação
19.
Proc Natl Acad Sci U S A ; 116(16): 7873-7878, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30936303

RESUMO

Magnetic tape heads are ubiquitously used to read and record on magnetic tapes in technologies as diverse as old VHS tapes, modern hard-drive disks, or magnetic bands on credit cards. Their design highlights the ability to convert electric signals into fluctuations of the magnetic field at very high frequencies, which is essential for the high-density storage demanded nowadays. Here, we twist this conventional use of tape heads to implement one in a magnetic tweezers design, which offers the unique capability of changing the force with a bandwidth of ∼10 kHz. We calibrate our instrument by developing an analytical expression that predicts the magnetic force acting on a superparamagnetic bead based on the Karlqvist approximation of the magnetic field created by a tape head. This theory is validated by measuring the force dependence of protein L unfolding/folding step sizes and the folding properties of the R3 talin domain. We demonstrate the potential of our instrument by carrying out millisecond-long quenches to capture the formation of the ephemeral molten globule state in protein L, which has never been observed before. Our instrument provides the capability of interrogating individual molecules under fast-changing forces with a control and resolution below a fraction of a piconewton, opening a range of force spectroscopy protocols to study protein dynamics under force.


Assuntos
Campos Magnéticos , Proteínas/química , Análise Espectral , Desenho de Equipamento , Fenômenos Mecânicos , Microscopia de Força Atômica , Dobramento de Proteína , Análise Espectral/instrumentação , Análise Espectral/métodos
20.
Astrobiology ; 19(3): 401-425, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30840506

RESUMO

Human explorers on the surface of Mars will have access to a far wider array of scientific tools than previous crewed planetary exploration missions, but not every tool will be compatible with the restrictions of this exploration. Spectrometers on flyby, orbital, and landed missions are currently used to determine the composition and mineralogy of geological materials of various types and sizes, from small fragments to celestial bodies in the solar system. Handheld spectrometers that are capable of in situ analyses are already used for geological exploration on Earth; however, their usefulness for human exploration missions and how data from multiple handheld instruments could be combined to enhance scientific return must be further evaluated. As part of the Biologic Analog Science Associated with Lava Terrains (BASALT) research project, we incorporated two handheld instruments, a visible-near infrared spectrometer and an X-Ray Fluorescence spectrometer, into simulated Mars exploration missions conducted on basaltic terrains in Idaho and Hawai'i. To understand the data quality provided by these handheld spectrometers, we evaluated their performance under varying conditions of measurement time, distance, angle, atmosphere, and sample matrix, and we compared data quality between handheld instruments and laboratory techniques. Here, we summarize these findings, provide guidelines and requirements on how to effectively incorporate these instruments into human exploration missions to Mars, and posit that future iterations of these instruments will be beneficial for enhancing science returned from human exploration missions.


Assuntos
Atmosfera/análise , Exobiologia/instrumentação , Meio Ambiente Extraterreno/química , Marte , Voo Espacial/instrumentação , Atmosfera/química , Exobiologia/normas , Guias como Assunto , Humanos , Silicatos/química , Análise Espectral/instrumentação , Análise Espectral/normas
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