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Molecules (Basel, Switzerland) Jul 2021In a global context where trading of wines involves considerable economic value, the requirement to guarantee wine authenticity can never be underestimated. With the... (Review)
Review
In a global context where trading of wines involves considerable economic value, the requirement to guarantee wine authenticity can never be underestimated. With the ever-increasing advancements in analytical platforms, research into spectroscopic methods is thriving as they offer a powerful tool for rapid wine authentication. In particular, spectroscopic techniques have been identified as a user-friendly and economical alternative to traditional analyses involving more complex instrumentation that may not readily be deployable in an industry setting. Chemometrics plays an indispensable role in the interpretation and modelling of spectral data and is frequently used in conjunction with spectroscopy for sample classification. Considering the variety of available techniques under the banner of spectroscopy, this review aims to provide an update on the most popular spectroscopic approaches and chemometric data analysis procedures that are applicable to wine authentication.
Topics: Food Analysis; Machine Learning; Magnetic Resonance Spectroscopy; Multivariate Analysis; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; Spectrum Analysis, Raman; Wine
PubMed: 34299609
DOI: 10.3390/molecules26144334 -
European Journal of Medicinal Chemistry Apr 2000The EVA descriptor is derived from fundamental IR and Raman range molecular vibrational frequencies. EVA is sensitive to 3-D structure, but has an advantage over... (Review)
Review
The EVA descriptor is derived from fundamental IR and Raman range molecular vibrational frequencies. EVA is sensitive to 3-D structure, but has an advantage over field-based 3-D QSAR methods inasmuch as it is invariant to both translation and rotation of the structures concerned and thus structural superposition is not required. The latter property and the demonstration of the effectiveness of the descriptor for QSAR means that EVA has been the subject of a great deal of interest from the modelling community. This review describes the derivation of the descriptor, details its main parameters and how to apply them, and provides an overview of the validation that has been done with the descriptor. A recent enhancement to the technique is described which involves the localised adjustment of variance in such a way that enhanced internal and external predictability may be obtained. Despite the statistical quality of EVA QSAR models, the main draw-back to the descriptor at present is the difficulty associated with back-tracking from a PLS model to an EVA pharmacophore. Brief comment is made on the use of the EVA descriptor for diversity studies and the similarity searching of chemical structure databases.
Topics: Spectrum Analysis; Structure-Activity Relationship
PubMed: 10858598
DOI: 10.1016/s0223-5234(00)00141-0 -
Scientific Reports Mar 2018The quality of therapeutic proteins such as hormones, subunit and conjugate vaccines, and antibodies is critical to the safety and efficacy of modern medicine....
The quality of therapeutic proteins such as hormones, subunit and conjugate vaccines, and antibodies is critical to the safety and efficacy of modern medicine. Identifying malformed proteins at the point-of-care can prevent adverse immune reactions in patients; this is of special concern when there is an insecure supply chain resulting in the delivery of degraded, or even counterfeit, drug product. Identification of degraded protein, for example human growth hormone, is demonstrated by applying automated anomaly detection algorithms. Detection of the degraded protein differs from previous applications of machine-learning and classification to spectral analysis: only example spectra of genuine, high-quality drug products are used to construct the classifier. The algorithm is tested on Raman spectra acquired on protein dilutions typical of formulated drug product and at sample volumes of 25 µL, below the typical overfill (waste) volumes present in vials of injectable drug product. The algorithm is demonstrated to correctly classify anomalous recombinant human growth hormone (rhGH) with 92% sensitivity and 98% specificity even when the algorithm has only previously encountered high-quality drug product.
Topics: Algorithms; Drug Stability; Equipment Design; Human Growth Hormone; Machine Learning; Mass Spectrometry; Models, Molecular; Oxidation-Reduction; Pharmaceutical Preparations; Proteolysis; Recombinant Proteins; Spectrum Analysis, Raman
PubMed: 29572496
DOI: 10.1038/s41598-018-23409-z -
Analytical Methods : Advancing Methods... Sep 2022Differential mobility spectrometry (DMS)-based detectors are being widely studied to detect chemical warfare agents, explosives, chemicals, drugs and analyze volatile...
Differential mobility spectrometry (DMS)-based detectors are being widely studied to detect chemical warfare agents, explosives, chemicals, drugs and analyze volatile organic compounds (VOCs). The dispersion plots from DMS devices are complex to effectively analyze through visual inspection. In the current work, we adopted machine learning to differentiate pure chemicals and identify chemicals in a mixture. In particular, we observed the convolutional neural network algorithm exhibits excellent accuracy in differentiating chemicals in their pure forms while also identifying chemicals in a mixture. In addition, we propose and validate the magnitude-squared coherence (msc) between the DMS data of known chemical composition and that of an unknown sample can be sufficient to inspect the chemical composition of the unknown sample. We have shown that the msc-based chemical identification requires the least amount of experimental data as opposed to the machine learning approach.
Topics: Data Analysis; Ion Mobility Spectrometry; Machine Learning; Spectrum Analysis; Volatile Organic Compounds
PubMed: 35968834
DOI: 10.1039/d2ay00723a -
Marine Drugs Apr 2010Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad... (Review)
Review
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.
Topics: Chitin; Chitosan; Magnetic Resonance Imaging; Mass Spectrometry; Molecular Structure; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis
PubMed: 20559489
DOI: 10.3390/md8051567 -
The Plant Journal : For Cell and... Nov 2021At the morphological and anatomical levels, the ionome, or the elemental composition of an organism, is an understudied area of plant biology. In particular, the ionomic...
At the morphological and anatomical levels, the ionome, or the elemental composition of an organism, is an understudied area of plant biology. In particular, the ionomic responses of plant-pathogen interactions are scarcely described, and there are no studies on immune reactions. In this study we explored two X-ray fluorescence (XRF)-based ionome visualisation methods (benchtop- and synchrotron-based micro-XRF [µXRF]), as well as the quantitative inductively coupled plasma optical emission spectroscopy (ICP-OES) method, to investigate the changes that occur in the ionome of compatible and incompatible plant-pathogen interactions. We utilised the agronomically important and comprehensively studied interaction between potato (Solanum tuberosum) and the late blight oomycete pathogen Phytophthora infestans as an example. We used one late blight-susceptible potato cultivar and two resistant transgenic plant lines (only differing from the susceptible cultivar in one or three resistance genes) both in control and P. infestans-inoculated conditions. In the lesions from the compatible interaction, we observed rearrangements of several elements, including a decrease of the mobile macronutrient potassium (K) and an increase in iron (Fe) and manganese (Mn), compared with the tissue outside the lesion. Interestingly, we observed distinctly different distribution patterns of accumulation at the site of inoculation in the resistant lines for calcium (Ca), magnesium (Mg), Mn and silicon (Si) compared to the susceptible cultivar. The results reveal different ionomes in diseased plants compared to resistant plants. Our results demonstrate a technical advance and pave the way for deeper studies of the plant-pathogen ionome in the future.
Topics: Disease Susceptibility; Host-Pathogen Interactions; Ions; Metals; Phosphorus; Phytophthora infestans; Plant Diseases; Plants, Genetically Modified; Solanum tuberosum; Spectrometry, X-Ray Emission; Spectrum Analysis; Synchrotrons
PubMed: 34407245
DOI: 10.1111/tpj.15469 -
International Journal of Molecular... Nov 2018In this study, melanin (BgM) was obtained from Boletus griseus. The chemical composition and structure of BgM were characterized by UV-visible absorption spectrum,...
In this study, melanin (BgM) was obtained from Boletus griseus. The chemical composition and structure of BgM were characterized by UV-visible absorption spectrum, Fourier transform infrared spectrum, elemental analysis, nuclear magnetic resonance, pyrolysis gas chromatography mass spectrometry, and ultra-performance liquid chromatography⁻high resolution mass spectrometry. The percentage contents of C, H, N, S and O elements were 56.38%, 5.86%, 6.17%, 2.44%, and 28.04%, and the S/N and C/N ratios were 0.17 and 10.66, respectively. The UV-vis spectrum of BgM showed a maximum absorption peak at 214 nm. Characteristic absorption peaks were observed at 3426, 1600 and 1105 cm, and BgM contained phenolic hydroxyl, amidogen, carbonyl, methylene, and methyl groups. Moreover, BgM is an eumelanin, and its main skeleton has both a benzene ring and an indole, and the branched chain mainly consists of alkanes, alcohols, and fatty acids. BgM was hydrolyzed by H₂O₂ and four compounds were tentatively analyzed from the UPLC-MS/MS profile. The chemical structure of BgM was characterized as 5,6-dihydroxyindole eumelanin, and the condensed molecular formula is [C(OR₁)₄(OR₂)₃HO₆N₄].
Topics: Basidiomycota; Gas Chromatography-Mass Spectrometry; Magnetic Resonance Spectroscopy; Melanins; Molecular Structure; Solubility; Spectrum Analysis; Tandem Mass Spectrometry
PubMed: 30477192
DOI: 10.3390/ijms19123736 -
Redox Biology Aug 2015Post-translational modifications (PTM) of proteins determine the activity, stability, specificity, transportability and lifespan of a protein. Some PTM are highly... (Review)
Review
Standardization and quality control in quantifying non-enzymatic oxidative protein modifications in relation to ageing and disease: Why is it important and why is it hard?
Post-translational modifications (PTM) of proteins determine the activity, stability, specificity, transportability and lifespan of a protein. Some PTM are highly specific and regulated involving various enzymatic pathways, but there are other non-enzymatic PTM (nePTM), which occur stochastically, depend on the ternary structure of proteins and can be damaging. It is often observed that inactive and abnormal proteins accumulate in old cells and tissues. The nature, site and extent of nePTM give rise to a population of that specific protein with alterations in structure and function ranging from being fully active to totally inactive molecules. Determination of the type and the amount (abundance) of nePTM is essential for establishing connection between specific protein structure and specific biological role. This article summarizes analytical demands for reliable quantification of nePTM, including requirements for the assay performance, standardization and quality control, and points to the difficulties, uncertainties and un-resolved issues.
Topics: Aging; Chromatography, High Pressure Liquid; Humans; Mass Spectrometry; Nuclear Magnetic Resonance, Biomolecular; Oxidation-Reduction; Peptides; Protein Processing, Post-Translational; Proteins; Quality Control; Spectrum Analysis, Raman
PubMed: 25909343
DOI: 10.1016/j.redox.2015.04.001 -
Optics Express Aug 2011Detecting and characterizing single nanoparticles and airborne viruses are of paramount importance for disease control and diagnosis, for environmental monitoring, and...
Detecting and characterizing single nanoparticles and airborne viruses are of paramount importance for disease control and diagnosis, for environmental monitoring, and for understanding size dependent properties of nanoparticles for developing innovative products. Although single particle and virus detection have been demonstrated in various platforms, single-shot size measurement of each detected particle has remained a significant challenge. Here, we present a nanoparticle size spectrometry scheme for label-free, real-time and continuous detection and sizing of single Influenza A virions, polystyrene and gold nanoparticles using split whispering-gallery-modes (WGMs) in an ultra-high-Q resonator. We show that the size of each particle and virion can be measured as they continuously bind to the resonator one-by-one, eliminating the need for ensemble measurements, stochastic analysis or imaging techniques employed in previous works. Moreover, we show that our scheme has the ability to identify the components of particle mixtures.
Topics: Adsorption; Gold; Influenza A virus; Limit of Detection; Nanoparticles; Particle Size; Polystyrenes; Spectrum Analysis; Virion
PubMed: 21934982
DOI: 10.1364/OE.19.016195 -
Bulletin Du Cancer Jan 2004Cervix cancer is a curable disease when diagnosed at an early stage. Screening of cervical lesions by cytology and colposcopy with in situ staining has allowed for... (Review)
Review
Cervix cancer is a curable disease when diagnosed at an early stage. Screening of cervical lesions by cytology and colposcopy with in situ staining has allowed for substantial progress in early diagnosis and consequently the cure of cervix cancer. Nevertheless, because of its low specificity, this approach generally implies repetitive tissue sampling and, thus a relative long time before the treatment of the lesions. Furthermore, the cost of preparation and analysis of biopsy samples is sufficiently high to represent a burden for industrialized countries and a virtual impossibility for the developing world. To overcome these problems, various biophotonic methods using optical fibers have been developed to allow for detection of cervical epithelial anomalies in a specific, fast and non-invasive way. This process, known as "optical biopsy", is based on the measurement of light-tissue interactions, which are analysed by various mathematical and data processing methods, to provide information on the metabolism and morphology of epithelial tissue. Currently investigated methods can be distinguished according to the type of signal used to probe the tissue (fluorescence, reflectance), the depth of analysed tissue (surface analysis, confocal imaging, tomography), the analysis modalities (spectral measurements or imaging), and the use of additive molecules (contrasting or photosensitizing agents, inorganic fluorophores). While most of the methods remain experimental, constant progress in the understanding of the mechanisms of light behavior in biological environments as well as advances in optical fibers technology, will make a number of these methods soon available for clinical practice to contribute efficiently to the reduction of biopsy number and cost of cervical screening.
Topics: Contrast Media; Female; Humans; Microscopy, Confocal; Microscopy, Polarization; Sensitivity and Specificity; Spectrometry, Fluorescence; Spectrum Analysis; Uterine Cervical Dysplasia; Uterine Cervical Neoplasms
PubMed: 14975804
DOI: No ID Found