3,618 results match your criteria Applied Spectroscopy[Journal]

Chemometrics for Raman Spectroscopy Harmonization.

Appl Spectrosc 2022 May 27:37028221094070. Epub 2022 May 27.

Institute of Catalysis and Petrochemistry, 16379CSIC-ICP, Madrid, Spain.

Raman spectroscopy is used in a wide variety of fields, and in a plethora of different configurations. Raman spectra of simple analytes can often be analyzed using univariate approaches and interpreted in a straightforward manner. For more complex spetral data such as time series or line profiles (1D), Raman maps (2D), or even volumes (3D), multivariate data analysis (MVDA) becomes a requirement. Read More

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Detection and Classification of Bacterial Cells After Centrifugation and Filtration of Liquid Specimens Using Laser-Induced Breakdown Spectroscopy.

Appl Spectrosc 2022 May 24:37028221092789. Epub 2022 May 24.

Department of Physics, 8637University of Windsor, Windsor, ON, Canada.

Five species of bacteria including , , , , and were deposited from suspensions of various titers onto disposable nitrocellulose filter media for analysis by laser-induced breakdown spectroscopy (LIBS). Bacteria were concentrated and isolated in the center of the filter media during centrifugation using a simple and convenient sample preparation step. Summing all the single-shot LIBS spectra acquired from a given bacterial deposition provided perfectly sensitive and specific discrimination from sterile water control specimens in a partial least squares discriminant analysis (PLS-DA). Read More

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A Prediction Model for Heavy Metal Contents in Soil Based on Deep Belief Network and Tree-Based Model.

Appl Spectrosc 2022 May 18:37028221104823. Epub 2022 May 18.

530247Yanshan University School of Electrical Engineering.

In order to extract useful information from XRF (X-ray fluorescence) spectrum, and establish a high-accuracy prediction model of soil heavy metal contents, a hybrid model combined Deep Belief Network (DBN) with tree-based model was proposed. The DBN was firstly introduced into feature extraction of XRF spectral data, which can obtain deep layer features of spectrum. Owing to the strong regression ability of tree-based model, it can offset the deficiency of DBN in prediction ability, so it was used for predicting heavy metal contents based on the extracted features. Read More

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Appl Spectrosc 2022 May;76(5):519-538

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Quantification of Rare Earth Elements in the Parts Per Million Range: A Novel Approach in the Application of Laser-Induced Breakdown Spectroscopy.

Appl Spectrosc 2022 May 12:37028221092051. Epub 2022 May 12.

Center for Renewable Carbon, 460436The University of Tennessee, Knoxville, TN, USA.

This work extends a previous percentage level concentration study of the optical emission spectra for six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), along with the transition metal, yttrium (Y) using laser-induced breakdown spectroscopy (LIBS). The concentration of these six rare earth elements and yttrium has been attempted for the first time systematically down to parts per million (ppm) concentration levels ranging from 30 to 300 ppm. The authors have developed multivariate models for each element capable of predicting concentration with acceptable to excellent levels of accuracy. Read More

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Monitoring Noble Gases (Xe and Kr) and Aerosols (Cs and Rb) in a Molten Salt Reactor Surrogate Off-Gas Stream Using Laser-Induced Breakdown Spectroscopy (LIBS).

Appl Spectrosc 2022 May 10:37028221088625. Epub 2022 May 10.

Radioisotope Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.

This study with surrogate materials shows that laser-induced breakdown spectroscopy (LIBS) is a robust tool with promising capability toward monitoring gaseous (Xe and Kr) and aerosol (Cs and Rb) species in an off-gas stream from a molten salt reactor (MSR). MSRs will continually evolve fission products into the cover gas flowing across the reactor headspace. The cover gas entrains Xe and Kr gases, along with aerosol particles, before passing into an off-gas treatment system. Read More

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Raman Spectroscopy Study of Skin Biopsies from Patients with Parkinson's Disease: New Trends in α-Synuclein Aggregation from the Amide I Region.

Appl Spectrosc 2022 May 4:37028221101634. Epub 2022 May 4.

Facultad de Ciencias27773Universidad Autonoma de San Luis Potosi.

Parkinson's disease (PD) is one of the most common neurological pathologies with a high prevalence worldwide. PD is characterized by Lewy bodies, whose major component is the aggregates of α-synuclein (αSyn) protein. Interestingly, recent works have demonstrated that skin biopsy studies are a promising diagnostic tool for evaluating α-synucleinopathies. Read More

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Spatial Resolution of Micro-Raman Spectroscopy for Particulate Lithium Iron Phosphate (LiFePO).

Appl Spectrosc 2022 Apr 28:37028221100843. Epub 2022 Apr 28.

Institute of Natural Sciences and Mathematics64974Ural Federal University named after the first President of Russia B N Yeltsin.

The fast-growing lithium battery industry needs quality control tools. Micro-Raman spectroscopy is a popular technique for structural characterization and can be used for impurity revealing. The problem is that the method resolution can be appropriately quantified for a sample with a simple planar geometry, like a single crystal. Read More

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Microwave Assisted Synthesis of Red-Emitting Copper Nanoclusters Using Trypsin as a Ligand for Sensing of Pb and Hg Ions in Water and Tobacco Samples.

Appl Spectrosc 2022 Apr 27:37028221100544. Epub 2022 Apr 27.

Chemistry123518Sardar Vallabhbhai National Institute of Technology.

In this work, microwave assisted method was developed for synthesis of red fluorescent copper nanoclusters by using trypsin as a template (trypsin-Cu NCs). The as- synthesized trypsin-Cu NCs are stable and water soluble, exhibiting fluorescence emission at 657 nm when excited at 490 nm. The as-prepared red emitting trypsin-Cu NCs were characterized by using several analytical techniques such as UV-Visible and fluorescence, fluorescence lifetime, Fourier transform infrared (FT-IR) and X-ray photoelectrons (XPS) spectroscopic techniques, respectively. Read More

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Terahertz Spectroscopy Study of the Stereoisomers of Threonine.

Appl Spectrosc 2022 Apr 25:37028221099958. Epub 2022 Apr 25.

12646Zhejiang Sci-Tech University.

The terahertz band contains a wealth of information about vibration and rotational energy levels, most of the vibration modes between amino acid molecules are in the THz band, so it reflects many unique absorption characteristics in the THz band. The use of terahertz time-domain spectroscopy can not only effectively identify different kinds of amino acids, but also distinguish various isomers of the same amino acid due to the varied vibration modes. The absorption spectra of four stereoisomers of threonine were investigated by terahertz time domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy (FTIR). Read More

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Luminescence of Aromatic Compounds During Ultrasonic Treatment of Tb(SO) Suspension in Commercial Gasoline.

Appl Spectrosc 2022 May 12:37028221098442. Epub 2022 May 12.

High-Energy Chemistry and Catalysis Laboratory, Institute of Petrochemistry and Catalysis, Ufa Federal Research Center, Ufa, Russia.

The spectral-luminescent properties of a suspension of terbium sulfate in commercial gasoline under sonication are studied. The following emitters are identified from the luminescence spectrum: *Tb ions in crystals, electronically excited molecules of arenes (benzene, toluene, and xylenes), and polycyclic aromatic hydrocarbons (PAHs) in the liquid phase of the suspension. The study of sonotriboluminescence in gasoline-heptane and heptane-xylene-PAH synthetic mixtures shows for the first time that there is an effective luminescence activator in gasoline, that is, terphenyl molecules. Read More

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Coupling Pulse Radiolysis with Nanosecond Time-Resolved Step-Scan Fourier Transform Infrared Spectroscopy: Broadband Mid-Infrared Detection of Radiolytically Generated Transients.

Appl Spectrosc 2022 May 25:37028221097429. Epub 2022 May 25.

Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA.

We describe the first implementation of broadband, nanosecond time-resolved step-scan Fourier transform infrared (S-FT-IR) spectroscopy at a pulse radiolysis facility. This new technique allows the rapid acquisition of nano- to microsecond time-resolved infrared (TRIR) spectra of transient species generated by pulse radiolysis of liquid samples at a pulsed electron accelerator. Wide regions of the mid-infrared can be probed in a single experiment, which often takes < 20-30 min to complete. Read More

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Green Textile Materials for Surface Enhanced Raman Spectroscopy Identification of Pesticides Using a Raman Handheld Spectrometer for In-Field Detection.

Appl Spectrosc 2022 May 20:37028221097130. Epub 2022 May 20.

Department of Chemistry and ILOC, 38909Niederrhein University of Applied Sciences, Krefeld, Germany.

Surface enhanced Raman spectroscopy (SERS) has evolved into a powerful analytical method in food and environmental analytical sciences due to its high sensitivity. Pesticide analysis is a major discipline therein. Using sustainable materials has become increasingly important to adhere to Green Chemistry principles. Read More

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Sub-Nanosecond Digital Signal Processing of Photomultiplier Tube Response Enabling Multiphoton Counting in Raman Spectroscopy.

Appl Spectrosc 2022 May 22:37028221095878. Epub 2022 May 22.

Civil Engineering Spectroscopy Laboratory, Lyles School of Civil Engineering, 311308Purdue University, West Lafayette, IN, USA.

This paper introduces a novel approach to achieve multiple photon counting for Raman spectroscopy. The multiphoton counting process is made possible by recording and analyzing the photomultiplier tube response to each pulse of a pulsed laser in a time-resolved Raman spectroscopy system. Conventional Raman spectroscopy typically considers photon arrivals as binary events assessed by a single threshold. Read More

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Standoff Detection System Using Raman Spectroscopy in the Deep-Ultraviolet Wavelength Region for the Detection of Hazardous Gas.

Appl Spectrosc 2022 May 25:37028221094632. Epub 2022 May 25.

Shikoku Research Institute Inc, Takamatsu, Japan.

This study developed a standoff detection system for Raman spectra in the deep-ultraviolet region to facilitate remote detection of various hazardous materials. Although Raman spectroscopy can distinguish various materials, the measurement of Raman spectra through standoff detection is challenging because of the low scattering cross-section of Raman scattering. The resonance Raman scattering effect in the deep-ultraviolet wavelength region is promising in terms of enhancing the spectral intensity of Raman scattering. Read More

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Temperature-Dependent Infrared Refractive Index of Polymers from a Calibrated Attenuated Total Reflection Infrared Measurement.

Appl Spectrosc 2022 May 25:37028221094598. Epub 2022 May 25.

Department of Chemistry, 8205University of Victoria, Victoria, BC, Canada.

We demonstrate a straightforward method by which a commonly available reference sample such as water can be used to calibrate an attenuated total internal reflection infrared absorbance measurement in order to account for the polarization of the beam incident on the internal reflecting element, and the spread of angles about the nominal angle of incidence. This enables quantitative comparison of attenuated total reflection-derived absorbance data with spectra calculated from optical constants. We then apply this calibration to the measurement of temperature-dependent absorption spectra of a polydimethylsiloxane sample. Read More

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Colon Cancer Grading Using Infrared Spectroscopic Imaging-Based Deep Learning.

Appl Spectrosc 2022 Apr 25;76(4):475-484. Epub 2022 Mar 25.

Cancer Center at Illinois, 124331University of Illinois at Urbana-Champaign, Urbana, IL, USA.

Tumor grade assessment is critical to the treatment of cancers. A pathologist typically evaluates grade by examining morphologic organization in tissue using hematoxylin and eosin (H&E) stained tissue sections. Fourier transform infrared spectroscopic (FT-IR) imaging provides an alternate view of tissue in which spatially specific molecular information from unstained tissue can be utilized. Read More

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Quantification of Lanthanides in a Molten Salt Reactor Surrogate Off-Gas Stream Using Laser-Induced Breakdown Spectroscopy.

Appl Spectrosc 2022 Mar 24:37028211070323. Epub 2022 Mar 24.

Radioisotope Science and Technology Division, 6146Oak Ridge National Laboratory, Oak Ridge, TN, USA.

To enable the deployment of molten salt reactor technology, the development of off-gas treatment systems and advanced monitoring tools capable of operating with high temperatures and radiation fields while delivering near real-time information is necessary. This study aims to fulfill this requirement and proposes laser-induced breakdown spectroscopy (LIBS) for monitoring molten salt aerosol streams. A sheath gas measuring method was developed to protect optical elements from aerosol particles and to ensure a relatively constant aerosol stream for measurement. Read More

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In Vivo Near-Infrared Noninvasive Glucose Measurement and Detection in Humans.

Appl Spectrosc 2022 May 24:37028221092474. Epub 2022 May 24.

State Key Laboratory of Precision Measuring Technology and Instruments, 12605Tianjin University, Tianjin, China.

In optical noninvasive glucose detection, how to detect the glucose-caused signals from the constant human variations and disturbed probing conditions is always the biggest challenge. Developing effective measurement strategies is essential to realize the detection. A near-infrared (NIR) spectroscopy-based strategy is studied to effectively solve the in vivo measurement issues, obtaining clean blood glucose-caused signals. Read More

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Two-Step Partial Least Squares-Discriminant Analysis Modeling for Accurate Classification of Edible Sea Salt Products Using Laser-Induced Breakdown Spectroscopy.

Appl Spectrosc 2022 May 26:37028221091581. Epub 2022 May 26.

Department of Chemistry, 34991Mokpo National University, Muan-gun, Korea.

Laser-induced breakdown spectroscopy (LIBS) has been widely applied to material classification in various fields, and partial least squares-discriminant analysis (PLS-DA) is one of the frequently used classical multivariate statistics to construct classification models based on the LIBS spectra. However, classification accuracy of the PLS-DA model is sensitive to the number of classes and their similarities. Considering this characteristic of PLS-DA, we suggest a two-step PLS-DA modeling approach to improve the classification accuracy. Read More

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Crosstalk-Free Excitation Scheme for Quantitative OH Laser-Induced Fluorescence in Environments Containing Excited CO.

Appl Spectrosc 2022 Apr 25:37028221088591. Epub 2022 Apr 25.

Department of Applied Physics, 3169Eindhoven University of Technology, Eindhoven, The Netherlands.

Spectral overlap in the single-photon laser-induced fluorescence between the 3064 Å system of OH and the third positive system of CO is detected in a highly-excited environment, namely, a CO-HO plasma. The overlap is distorting excitation and fluorescence spectra as well as fluorescence time decays of commonly used excitation transitions of OH. As a consequence, systematic errors are introduced into the determination of temperatures, gas compositions, and absolute number densities. Read More

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Analysis of Laser-Induced Breakdown Spectroscopy Data Acquired from Boundary of Two Matrices.

Appl Spectrosc 2022 May 12:37028221076852. Epub 2022 May 12.

Faculty of Mechanical Engineering, 48274Brno University of Technology, Brno, Czech Republic.

Laser-induced breakdown spectroscopy (LIBS) data obtained from the elemental imaging of heterogenous samples were processed with various chemometric algorithms. The intention was to cluster obtained characteristic spectra and to provide additional information about the sample surface composition and distribution of individual matrices. However, there is a gray zone on the boundary of two matrices and the consequent clustering of the spectra obtained on this boundary is ambiguous. Read More

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Review of Existing Standards, Guides, and Practices for Raman Spectroscopy.

Appl Spectrosc 2022 May 23:37028221090988. Epub 2022 May 23.

ELODIZ Ltd., High Wycombe, Buckinghamshire, UK.

Over the past decades Raman spectroscopy has been extensively used both on an industrial and academic level. This has resulted in the development of numerous specialized Raman techniques and Raman active products, which in turn has led to the adoption and development of standards and norms pertaining to Raman unit's calibration, performance validation, and interoperability. Purpose of the present review is to list, classify, and engage in a comprehensive analysis of the different standards, guides, and practices relating to Raman spectroscopy. Read More

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Statistical Considerations and Tools to Improve Histopathologic Protocols with Spectroscopic Imaging.

Appl Spectrosc 2022 Apr 16;76(4):428-438. Epub 2022 Mar 16.

97472Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.

Advances in infrared (IR) spectroscopic imaging instrumentation and data science now present unique opportunities for large validation studies of the concept of histopathology using spectral data. In this study, we examine the discrimination potential of IR metrics for different histologic classes to estimate the sample size needed for designing validation studies to achieve a given statistical power and statistical significance. Next, we present an automated annotation transfer tool that can allow large-scale training/validation, overcoming the limitations of sparse ground truth data with current manual approaches by providing a tool to transfer pathologist annotations from stained images to IR images across diagnostic categories. Read More

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Dependence on the Lens-to-Target Distance and with the Laser Energy at Constant Irradiance of the Laser-Induced Breakdown Spectroscopy Signal.

Appl Spectrosc 2022 May 13:37028221091291. Epub 2022 May 13.

Instituto de Ciencias Aplicadas y Tecnología, 7180Universidad Nacional Autónoma de México, México.

The emission signal-to-noise ratio (S/N) of a laser-produced plasma on an aluminum target at different focusing distances and at fixed irradiances was investigated. The plasma was produced by a 1064 nm nanosecond-pulsed laser and the energy and irradiances were varied in the 6-110 mJ and 0.4-700 GW cm ranges, respectively. Read More

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Comparison of Convolutional and conventional Artificial Neural Networks for Laser-Induced Breakdown Spectroscopy quantitative analysis.

Appl Spectrosc 2022 Mar 15:37028221091300. Epub 2022 Mar 15.

The introduction of Deep Learning algorithms for feature identification in digital imaging has paved the way for Artificial Intelligence applications that up to a decade ago were considered technologically impossible to achieve, from the development of driverless vehicles to the fully automated diagnostics of cancer and other diseases from histological images. The success of Deep Learning applications has, in turn, attracted the attention of several researchers for the possible use of these methods in chemometrics, applied to the analysis of complex phenomena as, for example, the optical emission of laser-induced plasmas. In this paper, we will discuss the advantages and disadvantages of Convolutional Neural Networks, one of the most diffused Deep Learning techniques, in Laser-Induced Breakdown Spectroscopy (LIBS) applications (classification and quantitative analysis), to understand the real potential of 'Deep LIBS' in practical everyday use. Read More

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Appl Spectrosc 2022 Apr 12;76(4):519. Epub 2022 Mar 12.

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Appl Spectrosc 2022 03;76(3):261-280

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Confocal Raman Microscopy for the Analysis of the Three-Dimensional Shape of Polymeric Microsphere Layers.

Appl Spectrosc 2022 Mar 8:37028211067827. Epub 2022 Mar 8.

Institut für Halbleitertechnik, 26527Technische Universität Braunschweig, Braunschweig, Germany.

The reconstruction of the three-dimensional (3D) morphology of polymeric microsphere layers based on confocal Raman microscopy was studied. Refraction of the Raman laser beam at the curved surface of the spheres broadens the focus volume inside the sphere. Compared to planar layers, the focus gets trapped inside the spheres such that the measured depth profiles are shifted and broadened. Read More

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Performance Improvement of Handheld Raman Spectrometer for Mixture Components Identification Using Fuzzy Membership and Sparse Non-Negative Least Squares.

Appl Spectrosc 2022 May 14;76(5):548-558. Epub 2022 Apr 14.

Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), 66374Jiangnan University, Wuxi, Jiangsu, China.

Due to the advantages of low price and convenience for end-users to conduct field-based, in-situ analysis, handheld Raman spectrometers are widely used in the identification of mixture components. However, the spectra collected by handheld Raman spectrometer usually have serious peak overlapping and spectral distortion, resulting in difficulties in component identification in the mixture. A novel method for mixture components identification based on the handheld Raman spectrometer was proposed in this study. Read More

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