Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Spectroscopy Research Articles

Inhibition properties of Vang tea-water extract for carbon steel corrosion in acidic environments

BackgroundMetallic corrosion saps the economy, pollutes the environment, and affects human health and life due to the related toxic chemicals, unwanted reactions, and project collapse, as well as contaminative products. The use of corrosion inhibitors could be a great help to reduce corrosion of metallic materials in severe working conditions. In recent years, natural products have been used for protecting against the corrosion of carbon steel. MethodsVang tea leaves - water extract (VTLWE) was recommended as a corrosion inhibitor with low-cost and a safe class of material for carbon steel in 1.0 M HCl, 0.5 M H2SO4, and their mixed acidic solutions. VTLWE raw materials were characterized by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and liquid chromatography-mass spectrometry (LC-MS). Electrochemical properties have been characterized by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization (PD). Post-immersion surface analyses were also evaluated using scanning electron microscopy (SEM), ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Significant FindingsThe electrochemical data showed that VTLWE posed as a mixed-type inhibitor with more cathodic characteristics and the inhibition effectiveness significantly depended on the VTLWE concentration that increased with an increase of VTLWE in 1.0 M HCl and 0.5 M H2SO4 solutions due to lower corrosion current density and higher polarization resistance. In addition, the results also indicated that 0.5 M H2SO4 solution was more aggressive than 1.0 M HCl solution and was subjected to a higher level of steel corrosion inhibition by VTLWE. Surface analysis results confirmed the occurrence of the organic film layer on the steel surface, assigning to the bonding of functional groups and heteroelements in VTLWE species that were available in investigated solutions. Therefore, the work could add VTLWE as new materials to inhibition systems, giving rise to the durable protection against steel corrosion and supplying inspiration in related applications.

Precise diagnosis of lung cancer enabled by improved FTIR-based machine learning

Micro-morphologic lesions of lung cancers (LC) are usually related to the developed tumors, lack of sensitivity to early lung cancer and specificity to tissue lesions of different origins due to similarity detected by medical imaging techniques. Attenuated total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR) using accessible blood samples has identified many biomolecular markers and characteristic spectral changes, which is related to early cancer diagnosis. In this study, for precise diagnosis of LCs, the in-situ serum-based ATR-FTIR spectroscopy experiments were carried out with 156 serum samples divided into 5 different types of LC groups and controls. The peak-to-peak area ratios between different functional groups contributed to the discovery of potential FTIR markers of LCs. Moreover, we also constructed a two-dimensional second-order derivative spectral (2D-SD-IR) feature dataset based on infrared molecular fingerprints (IMF) of LCs, including absorbance and wave number shifts of FTIR vibrational peaks for LC early diagnosis with low time cost-effectiveness and high classification accuracy. By comparing, the diagnosis models of partial least square discriminant analysis (PLS-DA) and back propagation (BP) neural network based on 2D-SD-IR are suitable to differentiate LCs and pathological stages accurately, and the high sensitivity and specificity of BP reached up to 98.7%. The proposed 2D-SD-IR machine learning protocol for LCs’ classification demonstrates the great advantage of aid clinical blood biochemical testing.

Fast and Deep Diagnosis Using Blood-Based ATR-FTIR Spectroscopy for Digestive Tract Cancers

Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) of liquid biofluids enables the probing of biomolecular markers for disease diagnosis, characterized as a time and cost-effective approach. It remains poorly understood for fast and deep diagnosis of digestive tract cancers (DTC) to detect abundant changes and select specific markers in a broad spectrum of molecular species. Here, we present a diagnostic protocol of DTC in which the in-situ blood-based ATR-FTIR spectroscopic data mining pathway was designed for the identification of DTC triages in 252 blood serum samples, divided into the following groups: liver cancer (LC), gastric cancer (GC), colorectal cancer (CC), and their different three stages respectively. The infrared molecular fingerprints (IMFs) of DTC were measured and used to build a 2-dimensional second derivative spectrum (2D-SD-IR) feature dataset for classification, including absorbance and wavenumber shifts of FTIR vibration peaks. By comparison, the Partial Least-Squares Discriminant Analysis (PLS-DA) and backpropagation (BP) neural networks are suitable to differentiate DTCs and pathological stages with a high sensitivity and specificity of 100% and averaged more than 95%. Furthermore, the measured IMF data was mutually validated via clinical blood biochemistry testing, which indicated that the proposed 2D-SD-IR-based machine learning protocol greatly improved DTC classification performance.

Use of ATR-FTIR Spectroscopy and Chemometrics for the Variation of Active Components in Different Harvesting Periods of Lonicera japonica.

Lonicera japonica Thunb is a commonly used Chinese herbal medicine, which belongs to the family Caprifoliaceae. The active components varied greatly during bud development. Research on the variation of the main active components is significant for the timely harvesting and quality control of Lonicera japonica. In this study, the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) combined with the chemometric method was performed to investigate the variability of different harvesting periods of Lonicera japonica. The preliminary characterization from ATR-FTIR fingerprints showed various characteristic absorption peaks of the main active components from the different harvesting times, such as flavonoids, organic acids, iridoids, and volatile oils. Additionally, principal component analysis (PCA) scatter plots showed that there was a clear clustering trend in the samples of the same harvesting period, and the samples of the different harvesting periods could be well distinguished. Finally, further analysis by the orthogonal partial least-squares discriminant analysis (OPLS-DA) showed that there were regular changes in flavonoids, phenolic acids, iridoids, and volatile oils in different harvesting periods. Therefore, ATR-FTIR, as a novel and convenient analytical method, could be applied to evaluate the quality of Lonicera japonica.

ATR-FTIR Method for Detection of Cassava Impurities in Indonesian Commercial White Pepper (Piper nigrum L.) Based on Principal Component Analysis

White pepper (Piper nigrum L.) is one of the most popular flavourings targeted for adulteration, i.e., cassava, resulting in quality loss and infringement on consumer rights and interests. Because it is easy and quick cleanup, minimal sample preparation, and excellent performance with strongly or thickly absorbed samples, the Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) spectrum signal is widely used to measure commercial herbal products. Manipulation of the spectrum signal can be used to quantify a sample as well as reduce its dimensionality. As a result, there is a lot of interest in developing methods for detecting cassava in commercial white pepper (Piper nigrum L.). The aim of the research was to get an ATR-FTIR spectroscopic technique combined with chemometrics to detect cassava as an adulterant in commercial white pepper (Piper nigrum L.). The chemical profiles of white pepper (Piper nigrum L.) and cassava were compared using principal component analysis (PCA). Bangka, Sudu, and Pontianak were used to collect white pepper (Piper nigrum L.)  and cassava. White pepper (Piper nigrum L.) and cassava were macerated in 96 percent ethanol for 3×24 hours before being concentrated with a rotary evaporator until thick. Each extract's IR spectral was measured using ATR-FTIR spectroscopy in the 4000-650 cm-1range. In addition, the IR spectral was clustered using PCA in the R program. To obtain the appropriate PCA model, we applied two IR spectral manipulation procedures (normal and derivative IR spectra) of the pure material. The PCA chosen was of the normal IR spectral type, with PC1 and PC2 values of 82.3 percent and 7.5 percent, respectively.. The projection of three commercial samples from the markets revealed that samples A and B were negative for cassava adulterant, while Sample C was suspected to be positive. Finally, the ATR-FTIR spectroscopic method tandem PCA was successful in clustering the presence or absence of cassava content in the commercial of Indonesian White Pepper

Saliva based non invasive screening of Oral Submucous Fibrosis using ATR-FTIR spectroscopy

Oral Submucous Fibrosis (OSMF) is a type of precancerous condition of Oral cancer and considered to have the greatest malignant potential. Biopsy is an ultimate option for the conformation of the malignancy. But the invasiveness of the procedure makes it interdict. Therefore, there is an urgent need to identify effective screening and diagnostic methods which would be less invasive, rapid, more accurate and cost effective. Here, we used Attenuated Total Reflection- Fourier transform infrared spectroscopy (ATR-FTIR) with Chemometric analysis coupled with estimation of total salivary protein to discriminate OSMF and Healthy Control (HC). The present study showed the specific Infrared spectrum for OSMF patients, which was specifically differentiated from HC based on the spectral shift of proteins/amide II, carbohydrate and nucleic acid using Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) with small data sets. ATR-FTIR spectroscopy of saliva coupled with total protein estimation can be used to discriminate between OSMF and HC. However, large sample size should be needed to evaluate the ATR-FTIR for consideration as a screening tool for an early diagnosis OSMF.

Adipose tissue estimates the postmortem interval based on ATR-FTIR spectroscopy

The estimation of the postmortem interval (PMI) is an essential part of forensic practice investigations. In this experiment, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and chemometrics were combined to explore the estimation of PMI in adipose tissue and the effect of temperature. Through principal component analysis (PCA) and two-factor ANOVA, we found that the change in adipose tissue degradation was mainly reflected in the peak intensity in the 1743 cm−1 (the bond between fatty acids and glycerol) decrease with the prolongation of PMI and the peak intensity in the 1711 cm−1 (free fatty acids) increase with the prolongation of PMI. Furthermore, temperature has a significant effect on the postmortem changes in adipose tissue; it will not change the mechanism of adipose tissue degradation but will affect the rate of adipose tissue degradation. Our next step was to establish partial least squares (PLS) regression models at different temperatures to estimate PMI. We found that the temperature affects the robustness and reliability of the model by affecting the rate of adipose tissue decomposition. In the high-temperature group, the adipose tissue changes more with time, which is beneficial to the detection of FTIR and the establishment of the model (25 °C: Rp2 = 0.82, RMSEP = 1.78 d; 35 °C: Rp2 = 0.82, RMSEP = 0.59 d), while low temperature is the opposite (5 °C: Rp2 = 0.12, RMSEP = 3.73 d; 15 °C: Rp2 = 0.60, RMSEP = 2.57 d). This study shows that the combination of ATR-FTIR and chemometrics is feasible to explore the estimation of PMI in adipose tissue and the effect of temperature.

Antibody CD133 Biofunctionalization of Ammonium Acryloyldimethyltaurate and Vinylpyrrolidone Co-Polymer-Based Coating of the Vascular Implants.

Current vascular stents, such as drug eluting stents (DES), have some serious drawbacks, like in stent restenosis and thrombosis. Therefore, other solutions are sought to overcome these post-implantations complications. These include the strategy of biofunctionalization of the stent surface with antibodies that facilitate adhesion of endothelial cells (ECs) or endothelial progenitor cells (EPCs). Rapid re-endothelialization of the surface minimizes the risk of possible complications. In this study, we proposed ammonium acryloyldimethyltaurate/vinylpyrrolidone co-polymer-based surface (AVC), which was mercaptosilanized in order to expose free thiol groups. The presence of free thiol groups allowed for the covalent attachment of CD133 antibodies by disulfide bridges formation between mercaptosilanized surface and cysteine of the protein molecule thiol groups. Various examinations were performed in order to validate the procedure, including attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) and Fourier transform Raman spectroscopy (FT-Raman), atomic force microscopy (AFM) and scanning electron microscopy (SEM). By means of ATR-FTIR spectroscopy presence of the CD133 antibody within coating was confirmed. In vitro studies proved good biocompatibility for blood cells without induction of hemolytic response. Thus, proposed biofunctionalized CD133 antibody AVC surface has shown sufficient stability for adapting as cardiovascular implant coating and biocompatibility. According to conducted in vitro studies, the modified surface can be further tested for applications in various biological systems.

Essential Oil Quality and Purity Evaluation via FT-IR Spectroscopy and Pattern Recognition Techniques

Essential oils are highly volatile, aromatic concentrated extracts from plants with wide applications. In this study, fast, easy-to-use attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was combined with chemometric techniques to verify essential oils’ taxonomy and purity. Principal component analysis (PCA) clustered 30 essential oil samples into three different groups based on plant botanical family and concentration. The first group contained highly concentrated oils from the Asteraceae family, the second group contained highly concentrated oils from the Lamiaceae family, while the last group contained three highly concentrated essential oils from different botanical families and commercial-grade essential oils. Thus, commercial-grade oil samples did not cluster with the corresponding concentrated oil samples despite their similar spectral patterns or botanical family. A loading plot identified infrared (IR) bands that correspond to carbonyl, vinyl, methyl and methylene group vibrations as the most important spectral bands that can be used as marker bands for discrimination between different botanical plant family groups. Hierarchical cluster analysis (HCA) confirmed the results obtained by PCA. ATR-FTIR spectroscopy combined with chemometric algorithms provides a direct and non-destructive method for chemotaxonomic classification of medicinal and aromatic essential oils and an assessment of their purity.

Application of Attenuated Total Reflection - Fourier Transform Infrared spectroscopy to characterize the degradation of littered multilayer food packaging plastics

Multilayer packaging is used in food consumables as disposable packs. The Attenuated Total Reflection - Fourier Transform Infrared spectroscopy (ATR-FTIR) spectroscopy is used in detecting defects in manufactured food packs. The consumed food packs like chips, biscuits and chocolates are littered without recycling. This is the first study that focused on the degradation potential of littered multilayer food packaging plastics from a dumpsite. The multilayer polymeric composition of various commercial packs was identified by ATR-FTIR spectroscopy based on the functional groups. The multilayer polymeric composition of a certain brand chips packs (commercial and littered) was similar. It has four polymers with the following sequence, Polypropylene (PP), Low-Density Polyethylene (LDPE), metalized-Polyethylene terephthalate (m-PET) and Linear Low-Density Polyethylene (LLDPE). Polypropylene was the printed layer, LLDPE was the inner food contact layer, whereas LDPE and m-PET were the binding layers of the other polymers in the pack. The degradation potential of littered packs from a dumpsite was characterized by ATR-FTIR spectroscopy. The littered multilayer chips packs (2016b and 2015c) were oxidized among the other packs. It was observed based on the OH group formation in the polyolefins, which states the surface degradation. The ATR-FTIR spectroscopy aided in the characterization of polymer degradation from a littered sample.

Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) Combined with Chemometrics Methods for the Classification of Lingzhi Species.

Due to the existence of Lingzhi adulteration, there is a growing demand for species classification of medicinal mushrooms by various techniques. The objective of this study was to explore a rapid and reliable way to distinguish between different Lingzhi species and compare the influence of data pretreatment methods on the recognition results. To this end, 120 fresh fruiting bodies of Lingzhi were collected, and all of them were analyzed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). Random forest (RF), support vector machine (SVM) and partial least squares discriminant analysis (PLS-DA) classification models were established for raw and pretreated second derivative (SD) spectral matrices to authenticate different Lingzhi species. The results of multivariate statistical analysis indicated that the SD preprocessing method displayed a higher classification ability, which may be attributed to the analysis of powder samples that requires removal of overlapping peaks and baseline shifts. Compared with RF, the results of the SVM and PLS-DA methods were more satisfying, and their accuracies for the test set were both 100%. Among SVM and PLS-DA, the training set and test set accuracy of PLS-DA were both 100%. In conclusion, ATR-FTIR spectroscopy data pretreated by SD combined with PLS-DA is a simple, rapid, non-destructive and relatively inexpensive method to discriminate between mushroom species and provide a good reference to quality assessment.

Characterization of apolipoprotein A-I peptide phospholipid interaction and its effect on HDL nanodisc assembly.

Background: Synthetic HDLs (sHDLs), small nanodiscs of apolipoprotein mimetic peptides surrounding lipid bilayers, were developed clinically for atheroma regression in cardiovascular patients. Formation of HDL involves interaction of apolipoprotein A-I (ApoA-I) with phospholipid bilayers and assembly into lipid-protein nanodiscs.Purpose: The objective of this study is to improve understanding of physico-chemical aspects of HDL biogenesis such as the thermodynamics of ApoA-I-peptide membrane insertion, lipid binding, and HDL self-assembly to improve our ability to form homogeneous sHDL nanodiscs that are suitable for clinical administration.Methods: The ApoA-I-mimetic peptide, 22A, was combined with either egg sphingomyelin (eSM) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipid vesicles to form sHDL. The sHDL assembly process was investigated through lipid vehicle solubilization assays and characterization of purity, size, and morphology of resulting nanoparticles via gel permeation chromatography (GPC), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Peptide-lipid interactions involved were further probed by sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The pharmacokinetics of eSM-sHDL and POPC-sHDL nanodiscs were investigated in Sprague Dawley rats.Results: sHDL formation was temperature-dependent, with spontaneous formation of sHDL nanoparticles occurring only at temperatures exceeding lipid transition temperatures as evidenced by DLS, GPC, and TEM characterization. SFG and ATR-FTIR spectroscopy findings support a change in peptide-lipid bilayer interactions at temperatures above the lipid transition temperature. Lipid-22A interactions were stronger with eSM than with POPC, which resulted in the formation of more homogeneous sHDL nanoparticles with longer in vivo circulation time as evidenced the PK study.Conclusion: Physico-chemical characteristics of sHDL are in part determined by phospholipid composition. Optimization of phospholipid composition may be utilized to improve the stability and homogeneity of sHDL.

Temperature-dependent hygroscopic behaviors of atmospherically relevant water-soluble carboxylic acid salts studied by ATR-FTIR spectroscopy

Model of aerosols and cloud formation processes requires extensive data on hygroscopic properties of water soluble organic species at lower troposphere relevant temperatures, which are ubiquitously found in atmospheric aerosols. Recent field studies (Kerminen et al., 1998) have revealed that sea salt aerosols can be efficiently chemically processed by water soluble carboxylic acids and lead to chloride depletion and formation of carboxylic acid salts. In this study, we report hygroscopic properties of four carboxylic acid salts, namely, sodium formate, sodium acetate, sodium oxalate and sodium succinate at temperatures commonly encountered in the lower troposphere ranging from 295.8 K to 270.0 K for the first time via attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Deliquescence relative humidity (DRH) and efflorescence relative humidity (ERH) of these carboxylic salts as a function of temperature were derived using both changes in water-to-solute (WSR) data and changes in band positions and shapes of carboxylate asymmetric and symmetric stretch modes. Hygroscopic data were also fitted by polynomial and corresponding coefficients were obtained. Our results have shown that these carboxylic acid salts exhibit strong temperature dependence and they would deliquesce at a lower humidity and are more likely to remain deliquesced when they are elevated in the troposphere. Since all these carboxylic acid salts present very different hygroscopic behaviors at lower temperatures from that of NaCl, chemically processed sea salt aerosols by carboxylic acids are expected to have fairly different phase state, size, and water content, consequently affecting their reactivity, lifetime, and ability to serve as cloud condensation nuclei.

Phenotyping Metastatic Brain Tumors Applying Spectrochemical Analyses: Segregation of Different Cancer Types

Metastatic brain tumors represent a significant proportion of tumors identified intraoperatively. A rapid diagnostic method, circumventing the need for histopathology studies, could prove clinically useful. As many spectroscopic studies have shown ability to differentitate between different tumor types, this technique was evaluated for use within metastatic brain tumors. Spectrochemical approaches [Raman and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) spectroscopy] were applied to determine how readily they may identify the primary site for the metastatic tumor. Metastases were from primary adenocarcinomas of lung (n = 7) and colorectum (n = 7), and for comparison, metastatic melanoma (n = 7). The objective was to determine if Raman or ATR-FTIR spectroscopy could delineate the origin of the primary tumor. The results demonstrate that there are marked similarities between the two adenocarcinoma groups and whilst Raman and ATR-FTIR can distinguish the three groups with limited success, classification accuracy is greatly improved when combining the adenocarcinoma groups. The use of such techniques in the clinical setting is more likely to be found intraoperatively, determining the presence of a tumor and suggesting the tumor class; however, traditional histopathology would still be needed to identify the primary origin of the tumor.

ATR-FTIR spectroscopy and μ-EDXRF spectrometry monitoring of enamel erosion caused by medicaments used in the treatment of respiratory diseases.

Medicaments essential for alleviation of diseases may sometime adversely affect dental health by eroding the enamel, owing to their acidic nature. It is therefore highly desirable to be able to detect these effects quickly and reliably. In this study, we evaluated the erosive capacity of four most commonly prescribed respiratory disease syrup medicaments on enamel using micro-energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Fifty-five enamel fragments obtained from 30 bovine teeth were treated with artificial saliva (S), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS); by immersing in 3mL of respective solutions for 1 min, three times a day at intervals of 1 hr, for 5 days. µ-EDXRF analysis of enamel surface did not reveal significant erosion caused by the medications. However, ATR-FTIR showed a detectable shift in the phosphate (PO4 ) antisymmetric stretching mode (ν3 ) at ∼985 cm-1 for AM, BR, and SS, indicating erosion. Multivariate statistical analysis showed that AC, AM, SS, and BR could be classified with 70%, 80%, 100%, and 100% efficiency from S (control), further highlighting the ability of ATR-FTIR to identify degree of erosion. This suggests ATR-FTIR may be used to rapidly and nondestructively investigate erosive effects of medicaments.

Glycation in human fingernail clippings using ATR-FTIR spectrometry, a new marker for the diagnosis and monitoring of diabetes mellitus

Although HbA1c is a good diagnostic tool for diabetes, the precarity of the health system and the costs limit the use of this biomarker in developing countries. Fingernail clippings contain ±85% of keratins, which are prone to glycation. Nail keratin glycation may reflect the average glycemia over the last months. We explored if attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) can be used as a non-invasive tool for assessing glycation in diabetes. Using ATR-FTIR spectroscopy, glycation and deglycation experiments with fructosamine 3-kinase allowed to identify the spectrum that corresponds with keratin glycation in fingernail clippings. Clippings of 105 healthy subjects and 127 diabetics were subjected to the standardized ATR-FTIR spectroscopy method. In vitro glycation resulted in an increased absorption at 1047cm-1. Following enzymatic deglycation, this peak diminished significantly, proving that the AUC between 970 and 1140cm-1 corresponded with glycated proteins. Within-run CV of the assay was 3%. Storage of nail clippings at 37°C for 2weeks did not significantly change results. In diabetics, glycated nail protein concentrations (median: 1.51μmol/g protein, IQR: 1.37-1.85μmol/g protein) were significantly higher than in the controls (median: 1.19μmol/g protein, IQR: 1.09-1.26μmol/g protein) (p<0.0001). ROC analysis yielded an AUC of 0.92 at a cut-off point of 1.28μmol/g nail (specificity: 82%; sensitivity: 90%). No correlation was observed between the glycated nail protein concentrations and HbA1c. Protein glycation analysis in fingernails with ATR-FTIR spectroscopy could be an alternative affordable technique for diagnosing and monitoring diabetes. As the test does not consume reagents, and the preanalytical phase is extremely robust, the test could be particularly useful in developing countries.

ATR-FTIR as a tool for assessing potential for chemical ageing in Spandex/Lycra®/elastane-based fabric collections

The Powerhouse Museum in Sydney, Australia houses the world's most significant and comprehensive collection of Speedo swimwear and accessories. The museum has identified a problem with the long-term storage of certain Spandex/Lycra® items where the elastane fibre has degraded leading to oil formation. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) determined that most of these garments were manufactured using nylon-elastane fibres, and the elastane component comprises polyetherurethane or polyesterurethane polymers. Certain polyesterurethanes are known to be vulnerable to hydrolysis, and this was confirmed for a subset of the collection using two chemical testing protocols, and a thermal testing protocol that reproduced the oil formation. A polyetherurethane garment in the collection was unchanged by these tests. The oil from the thermal testing was confirmed as a breakdown product of the polyester component of the elastane fibre, using ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The study demonstrates the value of ATR-FTIR for minimally invasive identification of elastane fabrics that may require specialized storage in a humidity-controlled environment.

Effect of Surface Reactivity on Watermark Formation Studied By Sessile Droplet Evaporation Approach

: Wet nanoscale etching of silicon is very dependent to surface reactive sites like step edges, defect densities, and crystallographic planes [1]. Ultra-pure water (UPW) used during rinsing and drying steps is etching silicon in the sub-nanometer range furthermore this silica residues will cause ring shape drying marks on the surface [2-3]. In this paper drying marks are characterized by physical and chemical characterization techniques  to evaluate the silicon etching process. The conversion of the  silicon hydrogen bond to silicon hydroxide is investigated on different crystal orientations to monitor the reactivity of the surface. Experiment & Measurement: The p-type (100) and (111) 200 mm silicon wafers (SunEdison) used had a resistivity of 1-5 Ω.cm. The samples were cleaned with an HF/HCl mixture to obtain a hydrophobic surface with a contact angle of around 70◦. Atomically smooth silicon (111) was prepared by a NH4F (Sigma-Aldrich 99%) etching process in a closed oxygen free etching cell [4]. Double side polished silicon (100) and (111) wafer were used as a crystal in attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to monitor the hydrogen termination. The 3D profile of the WM formed after evaporation of a UPW sessile droplet was measured using a KLA-Tencor High Resolution Profilometer [3]. Results & Discussion:The impact of the crystal orientation on the WM residue is studied by comparing the results of droplet drying on p-type Si (100) versus (111) in the dark (40% relative humidity). Although AFM analysis confirms a smooth surface finish (RMS = 0.2 nm) for the HF treated (100) and (111) surface, no clear atomic planes are observed. Fig. 1 shows the etch rate of silicon in the dark under clean room conditions. The etch rate is calculated based on residue volume (measured by profiliometry) divided by the droplets initial wetting area, and evaporation time. Fig. 2 shows the decrease in the amplitude of the silicon hydride peak, measured by ATR-FTIR spectroscopy, as a function of time (the rate of decrease is faster in the Si (100), case as might be expected). The fact that hydride termination of the surface disappears only slowly gives information about the etching mechanism, that will be discussed in the proceeding. The higher stability of the (111) surface is attributed to the higher number of back-bonds for Si-surface atoms in case of (111) (with 3 back-bonds) versus the (100) case (with 2 back-bonds). The experimental result confirms the chemical dissolution process but a difference in surface stability is observed. WM formation was studied in the dark since previous work [3] showed that light increases the etch rate markedly, thus complicating the interpretation. In order to investigate the impact of surface morphology on WM formation, atomically smooth surfaces were prepared by immersing a p-type Si (111) substrates (miscut angle <0.07º) in oxygen free  NH4F. The results are shown in Figure 3. By comparing the result of HF-pretreated and NH4F-pretreated surfaces it is clear that the atomically smooth surface shows reduced reactivity compared to the rough HF last surface. Due to lower step edge density the chemical reactivity of the surface decreases and WM residue formation is suppressed. Conclusion: This study showed the effect of surface imperfections on dissolution process by WM formation. It is shown that the silicon (111) dissolution process decreased in case of atomically smooth surface. The dissolution can be further suppressed by performing rinsing and drying process in dark ambient.

Authentication of canned fish packing oils by means of Fourier transform infrared spectroscopy

The authentication of packing oil from commercial canned tuna and other tuna-like fish species was examined by means of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and chemometrics. Using partial least squares discriminant analysis (PLS-DA), it was possible to differentiate olive oil from seed oils. Discrimination of olive oil from high-oleic sunflower oil was possible, despite the latter having a degree of unsaturation more similar to olive oil than to sunflower oil. However, in the samples analyzed, sunflower oil could not be differentiated clearly from those labeled with the generic term “vegetable oil”. Furthermore, the authentication of extra virgin olive oil, although more difficult, could be achieved using ATR-FTIR spectroscopy. The method could be applied regardless of fish type, without interference from fish lipids.

Segregation of ovarian cancer stage exploiting spectral biomarkers derived from blood plasma or serum analysis: ATR-FTIR spectroscopy coupled with variable selection methods.

Ovarian cancer is a solid tumor and a leading cause of mortality. Diagnostic tools for the detection of early stage (stage I) ovarian cancer are urgently needed. For this purpose, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) coupled with variable selection methods, successive projection algorithm or genetic algorithm (GA) combined with linear discriminant analysis (LDA), were employed to identify spectral biomarkers in blood plasma or serum samples for accurate diagnosis of different stages of ovarian cancer, histological type and segregation based on age. Three spectral datasets (stage I vs. stage II-IV; serous vs. non-serous carcinoma; and, ≤60 years vs. >60 years) were processed: sensitivity and specificity required for real-world diagnosis of ovarian cancer was achieved. Toward segregating stage I vs. stage II-IV, sensitivity and specificity (plasma blood) of 100% was achieved using a GA-LDA model with 33 wavenumbers. For serous vs. non-serous category (plasma blood), the sensitivity and specificity levels, using 29 wavenumbers by GA-LDA, were remarkable (up to 94%). For ≤60 years and >60 years categories (plasma blood), the sensitivity and specificity, using 42 wavenumbers by GA-LDA, gave complete accuracy (100%). For serum samples, sensitivity and specificity results gave relatively high accuracy (up to 91.6% stage I vs. stage II-IV; up to 93.0% serous vs. non-serous; and, up to 96.0% ≤60 years vs. >60 years) using several wavenumbers. These findings justify a prospective population-based assessment of biomarkers signatures using ATR-FTIR spectroscopy as a screening tool for stage of ovarian cancer.