Unravelling the Encapsulation of DNA and Other Biomolecules in HAp Microcalcifications of Human Breast Cancer Tissues by Raman Imaging.

Microcalcifications are detected through mammography screening and, depending on their morphology and distribution (BI-RADS classification), they can be considered one of the first indicators of suspicious cancer lesions. However, the formation of hydroxyapatite (HAp) calcifications and their relationship with malignancy remains unknown. In this work, we report the most detailed three-dimensional biochemical analysis of breast cancer microcalcifications to date, combining 3D Raman spectroscopy imaging and advanced multivariate analysis in order to investigate in depth the molecular composition of HAp calcifications found in 26 breast cancer tissue biopsies.

Review on the photonic techniques suitable for automatic monitoring of the composition of multi-materials wastes in view of their posterior recycling.

In the increasingly pressing context of improving recycling, optical technologies present a broad potential to support the adequate sorting of plastics. Nevertheless, the commercially available solutions (for example, employing near-infrared spectroscopy) generally focus on identifying mono-materials of a few selected types which currently have a market-interest as secondary materials. Current progress in photonic sciences together with advanced data analysis, such as artificial intelligence, enable bridging practical challenges previously not feasible, for example in terms of classifying more complex materials.

Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study.

The variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a 'primary' setup and the test data are generated on 'replicate' setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable.

Application of ATR-FTIR spectroscopy and chemometrics for the discrimination of human bone remains from different archaeological sites in Turkey.

Examining diagenetic parameters such as the organic carbonate contents and the crystallinity of bone apatite quantify the post-mortem alteration of bone. Burial conditions are one of the factors that can influence the diagenesis process. We studied the changes to the organic and mineral components and crystallinity of human bone remains from five Medieval sites in Turkey: Hakemi Use, Komana, İznik, Oluz Höyük and Tasmasor using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and principal component analysis (PCA).

Sensitive Raman detection of human recombinant interleukin-6 mediated by DCDR/GERS hybrid platforms.

Recombinant human interleukin-6 (IL-6) is a key cytokine that plays an important role in the immune system and inflammatory response, explaining why any modification of its concentration in biological fluids is considered a signal of a pathological condition. Therefore, it is important to develop alternative, highly sensitive and reliable analytical methodologies to detect and identify this analyte in biological fluids. Herein, we present a proof of concept for the development of a new analytical hybrid platform for IL-6 detection that is based on the combination of drop-coating deposition Raman (DCDR) spectroscopy and graphene-enhanced Raman spectroscopy (GERS) effects.

Infrared spectroscopy as an alternative methodology to evaluate the effect of structural features on the physical-chemical properties of inulins.

Two types of inulins of different composition were investigated in the glassy and in the crystalline states, at relative humidities within 11 and 97%. The melting and glass transition temperatures (Tm, Tg), and their crystallinity indexes (CI) were determined by modulated differential-scanning calorimetry (MDSC) and wide-angle X-ray scattering (WAXS), respectively. In parallel assays, Fourier transform-infrared spectroscopy (FTIR) coupled to principal component analysis (PCA) enabled a physical-chemical and structural characterization of samples, explaining 90% of the total variance.

Raman spectroscopy quantification of eumelanin subunits in natural unaltered pigments.

Eumelanins are large polymers composed of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Reactive oxygen species generation is higher during the synthesis of DHI than during the synthesis of DHICA; thus, the production of eumelanins with high relative DHI contents may compromise the viability of cells and organisms. Here, we show that dispersive Raman spectroscopy allows a noninvasive direct detection and quantification of DHI and DHICA in unaltered eumelanins that can be applied to the analysis of natural pigments in biological tissues.

Transcriptome analysis in tissue sectors with contrasting crocins accumulation provides novel insights into apocarotenoid biosynthesis and regulation during chromoplast biogenesis.

Crocins, the red soluble apocarotenoids of saffron, accumulate in the flowers of Crocus species in a developmental and tissue-specific manner. In Crocus sieberi, crocins accumulate in stigmas but also in a distinct yellow tepal sector, which we demonstrate contains chromoplast converted from amyloplasts. Secondary metabolites were analysed by LC-DAD-HRMS, revealing the progressive accumulation of crocetin and crocins in the yellow sector, which were also localized in situ by Raman microspectroscopy.

Conformational changes in matrix-isolated 6-methoxyindole: Effects of the thermal and infrared light excitations.

Conformational changes induced thermally or upon infrared excitation of matrix-isolated 6-methoxyindole were investigated. Narrowband near-infrared excitation of the first overtone of the N-H stretching vibration of each one of the two identified conformers is found to induce a selective large-scale conversion of the pumped conformer into the other one. This easily controllable bidirectional process consists in the intramolecular reorientation of the methoxy group and allowed a full assignment of the infrared spectra of the two conformers.

Conformational Switching by Vibrational Excitation of a Remote NH Bond.

Here we describe an unprecedented reversible interconversion between two conformational states, accomplished by selective vibrational excitation of a bond remotely located in relation to the isomerizing fragment. In contrast to previous studies reporting conformational changes via vibrational excitation of a nearby OH group, in this study the transformations were successfully achieved by excitation of a distant NH stretching coordinate. The syn and anti forms of monomeric 6-methoxyindole, which differ in the orientation of the methoxy group, were trapped in low-temperature inert matrixes and characterized spectroscopically.

Role of S-layer proteins in the biosorption capacity of lead by Lactobacillus kefir.

The role of S-layer proteins (SLP) on the Pb(2+) sequestrant capacity by Lactobacillus kefir CIDCA 8348 and JCM 5818 was investigated. Cultures in the stationary phase were treated with proteinase K. A dot blot assay was carried out to assess the removal of SLP.

Determination of amorphous/rubbery states in freeze-dried prebiotic sugars using a combined approach of near-infrared spectroscopy and multivariate analysis.

Galacto-oligosaccharides (GOS) and lactulose are well-recognized prebiotics widely used in functional food and pharmaceutical products, but there is still a lack of knowledge regarding their physical-chemical properties. In this study, a physical-chemical approach on two GOS of different composition (GOS Cup Oligo H-70® and GOS Biotempo) and lactulose was assessed. Mid infrared and Raman spectra of the freeze-dried sugars allowed their structural characterization in the amorphous state, lactulose, showing the main spectral differences.

Galacto-oligosaccharides and lactulose as protectants against desiccation of Lactobacillus delbrueckii subsp. bulcaricus.

Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 was dehydrated on desiccators containing silica gel in the presence of 20% w/w of two types of galacto-oligosaccharides (GOS Biotempo and GOS Cup Oligo H-70®) and lactulose, until no changes in water desorption were detected. After rehydration, bacterial growth was monitored at 37°C by determining: (a) the absorbance at 600 nm and (b) the near infrared spectra (NIR).

Generation and characterization of a 4π-electron three-membered ring 1H-diazirine: An elusive intermediate in nitrile imine-carbodiimide isomerization.

The photolysis at 222 nm of 5-methyltetrazole isolated in a cryogenic argon matrix leads to formation of methyl nitrile imine as primary product. Subsequent irradiation at 328 nm induces transformation of the nitrile imine into 4π-electron three-membered-ring 3-methyl-1H-diazirine, which photorearranges to give methyl carbodiimide. These products were characterized by IR spectroscopy and theoretical calculations.

Tetrazole acetic acid: tautomers, conformers, and isomerization.

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom.

Structure and UV-induced photochemistry of 2-furaldehyde dimethylhydrazone isolated in rare gas matrices.

In this work, a combined matrix isolation FTIR and theoretical DFT(B3LYP)/6-311++G(d,p) study of 2-furaldehyde dimethylhydrazone (2FDH) was performed. According to calculations, two E and two Z conformers exist, the E forms having considerably lower energy than the Z forms. The absence of relevant sterical hindrance between the two substituents around the CN bond (dimethylamino and 2-furyl) in the E structures and an extended π-p electron delocalization in the hydrazone moiety determines the higher stability of these species relatively to the Z structures.

Occurrence of toxic cyanobacterial blooms in rio de la plata estuary, Argentina: field study and data analysis.

Water samples were collected during 3 years (2004-2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified.

Conformers, infrared spectrum and UV-induced photochemistry of matrix-isolated furfuryl alcohol.

The infrared spectra of furfuryl alcohol (2-furanmethanol, FFA) were investigated for FFA monomers isolated in low-temperature argon matrices. The structural interpretation of the obtained experimental spectra was assisted by analysis of the molecule's conformational landscape. According to the DFT(B3LYP)/6-311++G(d,p) calculations, five different minimum energy structures were found on the potential energy surface of the molecule.

Use of Raman spectroscopy and chemometrics for the quantification of metal ions attached to Lactobacillus kefir.

Aims: To set-up an experimental and analytical methodology to evaluate the feasibility of developing simple, accurate and quantitative models based on Raman spectroscopy and multivariate analysis for the quantification of metal ions adsorbed to the bacterial surface of Lactobacillus kefir.

Methods And Results: One millilitre cultures from two strains of Lact. kefir in the stationary phase were harvested and washed twice with ultra pure water.

Experimental (IR/Raman and 1H/13C NMR) and theoretical (DFT) studies of the preferential conformations adopted by L-lactic acid oligomers and poly(L-lactic acid) homopolymer.

L-Lactic acid (L-LA) oligomers (up to the pentamer) were studied by three complementary approaches: vibrational (IR and Raman) and NMR ((1)H and (13)C) spectroscopies and DFT calculations. Vibrational and NMR spectra of L-LA oligomers and poly(L-lactic acid) (PLLA) homopolymer were recorded at room temperature and interpreted. Further insight into the structures (conformations) of the title systems was provided by theoretical B3LYP/6-311++G(d,p) studies.

Development of a method based on chemometric analysis of Raman spectra for the discrimination of heterofermentative lactobacilli.

In this work, a method based on Raman spectroscopy in combination with Principal Component Analysis (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA) has been developed for the rapid differentiation of heterofermentative related lactobacilli. In a first approach, Lactobacillus kefir strains were discriminated from other species of heterofermentative lactobacilli: Lb. parakefir and Lb.

[Ultraviolet absorption of prescription sunblocks in Mexico].

Background: An appropriate sunscreen should provide high and broad ultraviolet protection both for the B and A range. The objective was quantify the ultraviolet absorption spectrum in sunscreens available for medical prescription, and analyze its relationship with the labeled Sun Protection Factor (SPF).

Material And Methods: Thirty-nine sunscreens were analyzed in vitro using ultraviolet spectroscopy following exposure to simulated solar irradiation.

Detection of the presence of antibodies against Toxoplasma gondii in human colostrum by Raman spectroscopy and principal component analysis.

More than 60 million people in the United States and 23 million people in Mexico probably are infected with the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness. However, for people whose immune system is compromised, the consequences can be fatal. Toxoplasmosis is detected indirectly by different serological tests, where the sample requires a previous preparation.