In this, characteristic peak corresponding to the drug substance is chosen and log I0/It of peaks for standard and test sample is compared. Taking into consideration the nonhealth impacts and health risks associated with obesity, there is an urgent need for early diagnosis and treatment of this global burden. Infrared spectroscopy and spectroscopic imaging, are robust, label free and inherently non-destructive methods with a high chemical specificity and sensitivity that are frequently employed in forensic science research and practices. Furthermore, FTIR spectra may give information about the disease-induced changes at very early stage, earlier than they become visible. Spectral differences indicated differences in lipid structure and content of BFMI lines, which may originate from different insulin sensitivity levels of the lines. It also allows the detection of lower concentrations of biological components ranging from biomolecules, membranes, cells, tissues, and body fluids. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. Representation of a spectrum before (left) and after (right) linear baseline correction. A new absorption peak at 1560.88 cm−1 appeared in the COS-RS complex spectra, and the shape of typical absorption peaks for starch from 1180 to 953 cm−1 also changed. In the ER, proteins are folded into their native confirmation and undergo posttranslational modifications, which are important for their structure and activity. If absorbed energy is plotted as a function of wavenumber, an IR spectrum is observed. Such materials include Diamond, zinc selenide (ZnSe), germanium (Ge), silicon (Si), and thallium/iodide. The use of the bright IR source emitted by synchrotron radiation (SR) allowed the investigation of the biochemical composition at cellular level. Polymers. The rate of disappearance of a characteristic absorption band of the reactant group and/or the rate of appearance of the characteristic absorption band of the product group due to formation of product is observed. The degree of unsaturation was obtained from the ratio of the integrated area of unsaturated lipids (2992–3020 cm−1) to the integrated area of saturated lipids (2830–2980 cm−1), showed stepwise decreases going from colder-exposed to warmer-exposed BAT. Promising new experimental tools and models will help for elucidating remaining questions related to obesity and may be critical for the development of the new therapeutic strategies. Animals subjected to enriched diets were obese. Infrared radiation from the spectrometer is focused onto a sample placed on a standard microscope x–y stage. A state of excessive accumulation of body fat results in simultaneous development of a number of metabolic pathologies including insulin resistance, glucose intolerance, diabetes mellitus, hypertension, dyslipidemia, stroke, fatty liver disease, coronary heart diseases, cancer, and metabolic diseases [6, 7, 8]. Smoothing is used to reduce noise in data. Furthermore, supervised analysis methods have not been applied to IR spectra yet for the obesity differentiation. FTIR spectroscopy is a rapid, very sensitive, cost-effective, and easy-use technique. Therefore, visceral fat is thought to be the more dangerous adipose tissue. The liver is the major organ of lipid metabolism and can store lipids, which could lead to fatty liver syndrome. El-Menshawe et al. Identification of functional group and structure elucidation. These associations are affected by adipose tissue distributions. FTIR spectroscopy and synchrotron X-ray fluorescence (SRXRF) microprobe techniques show that brain areas implicated appetite control, upon experimental treatment by either anodal-type tDCS (atDCS) or cathodal-type tDCS (ctDCS). In this chapter, after mentioning about the basis of IR spectroscopy and microscopy, the sample preparation techniques, spectral analysis methods together with the chemometric tools used in IR spectroscopy, the topic of obesity will be given briefly. It uses a source that transmits IR wavelengths of light to view an image of the sample. The shift in the position of the C=O stretching and the PO2− anti-symmetric double stretching bands gives information about hydration status of these functional groups [20, 24]. When the applied IR energy is equal to the energy difference between vibrational states, absorption of IR radiation takes place and a peak is observed. 2 Infrared Spectroscopy: Fundamentals and Applications but by the mid 1950s, diffraction gratings had been introduced into disper-sive machines. UV Spectroscopy- Principle, Instrumentation, Applications. According to this metric, the grading of body fatness can be classified as overweight (BMI: 25–30 kg/m2), obese (BMI: 30–40 kg/m2), and morbidly obese (BMI > 40 kg/m2) [12]. Some of the major applications of IR spectroscopy are as follows: 1. That means IR spectroscopy has the capacity of analysing the biological systems as reagent free, operator independent, diagnosis of diseases at very early stage. Biomolecular content, concentration, and structure were determined by ATR-FTIR spectroscopy. Applications. This is because large number of absorption bands is observed in the IR spectra of organic molecules and the probability that any two compounds will produce identical spectra is almost zero. According to corresponding peaks, functional group can be determined. BAT is rich in protein content and mitochondria than that of WAT. Figure 2 shows a representative IR spectrum of a human adipose tissue. Instrumentation and sampling techniques. This allows both spatial and spectral information about the sample structure to be collected. Barbara is the author of three other books published by John Wiley and Sons, Ltd, namely Modern Infrared Spectroscopy and Biological Applications of Infrared Spectroscopy, both in the ACOL series of open learning texts, and Polymer Analysis in this current AnTS series of texts. Finally, tissue samples are thaw-mounted on IR-transparent CaF2 or BaF2 windows for IR mapping and data processing [36]. Complementary H-1 NMR measurements confirmed the findings from this ratio in BAT. This effect of obesity on the VAT highly correlates with the SCAT. The C-H stretching, amide I-IV, and PO42− anti-symmetric stretching regions were investigated. This study revealed that, FTIR imaging is a promising technique to quantify cold-induced biochemical changes in BAT and s-WAT in a label-free manner [72]. IR spectrometers have been commercially available since the 1940s [16]. IR spectroscopy products measure the transition between stretching vibrations (symmetrical and anti-symmetrical types) and bending vibrations. A representative baseline corrected normalized FTIR spectrum of a human adipose tissue in the 4000–750 cm−1 region. Then, how IR spectroscopy can be applied to characterization and diagnosis of obesity will be discussed in detail. In addition, results are not dependent on the operator but to computational analyses of the spectra. The spectra used in spectroscopy vary from ultra-violet, visible, infrared ranges. Entire IR region is divided into group frequency region and fingerprint region. The mid-IR spectra were acquired from serum, and then analyzed to develop a predictive model of the steatosis level. The ratio between rScO 2 and systemic oxygen saturation (SaO 2 ) estimates cerebral fractional tissue oxygen extraction (cFTOE), reflecting oxygen utilization. We are a community of more than 103,000 authors and editors from 3,291 institutions spanning 160 countries, including Nobel Prize winners and some of the world’s most-cited researchers. In terms of structural studies, there is no information yet in the literature about obesity-induced protein structural changes. [76] studied the effect of dietary fatty acid composition on lipolysis. Because they are supervised methods, there is a need for cross-validation and independent validation dataset. Vibrational spectroscopy includes Raman spectroscopy, IR spectroscopy, and Tera Hertz(THz) spectroscopy. The sample preparation methods are chosen according to the size, nature, and condition of the specimen. The large number of wavelengths emitted by these systems makes it possible to investigate their structures in detail, including the electron configurations of ground and various excited states. Rao, Chemical Applications of Infrared Spectroscopy, Academic Press, New York, 1963. It can be determined by characteristic peaks. Cross-linking between RS and COS was confirmed by FTIR spectroscopy analysis. Unhealthy diet habits, reduced physical activity together with modern lifestyle, urbanization, genetic predisposition, and aging cause an obesity-promoting (obesigenic) environment and contribute to the higher prevalence of these diseases across all age groups [5]. This process continues until the two spectra (spectrum/spectrum or spectrum/cluster or cluster/cluster) are merged into a new cluster. However, bound water or inter-bilayer water still exists in the biological systems [26]. According to Beer–Lambert law, the signal intensity or more accurately the area under the bands gives concentration information. In another recent study, rats fed with a high-fat diet were treated with resistant starch (RS), chitosan oligosaccharide (COS), and a combination of these complexes with the aim of determining their effect on controlling blood glucose levels and improving insulin resistance. Besides aqueous samples, dry samples, homogeneous soft tissues, or hard tissues can also be studied with the ATR–IR spectroscopy by directly placing a small portion of the sample on the crystal and then applying the same pressure to all the samples. It is also employed in forensic analysis in civil and criminal analysis. This instrument employs an interferometer and exploits the well-established mathematical process of Fourier-transformation. Thus, the first principle component, i.e., PC1, expresses most of the variance in the data; PC2 expresses the second largest variance in the data and so on [44]. Since the SCAT is more accessible than the VAT for medical interventions, this type of adipose tissue can be used preferably in biopsies and bariatric operations [43]. In recent years, scientific researchers have continued to increase the performance of this technique on clinical cases such as cancers and metabolic disorders. This study showed the efficiency and suitability of ATR-FTIR spectroscopy to identify quantitative trait loci (QTLs) that influence various traits and heightened the power of gene mapping studies. The study showed the extracted pectin has potential use in the anti-obesity formulations [79]. The bandwidth of the CH2 stretching bands gives lipid fluidity information. First, visual inspection of the spectra should be done to remove bad quality spectra. However, smoothing also induces distortion in peak shape and may erase small peaks and shoulders [40]. In recent years, there have been considerable advances in FTIR microscopy by reaching sample size at the order of microns. During sample preparation for FTIR microspectroscopy, tissue sections can either be directly obtained using a cryotome or be initially embedded into different kinds of embedding media and then cryo-sectioned. This technique can reduce a large scale of spectra to a point in a space by using linear transformation. Inorganic molecules. Due to its technical problems such as the difficulty in determining bony prominences, this method identifies obesity risk poorly. They differ in their degree of vascularization and innervation. Aboualizadeh et al. PC1 versus PC2 scores plot of the second derivative vector normalized spectra in the same range of SCAT (C) and VAT (D). It is applied before data analysis but should be kept minimum not to introduce some artifacts and should be performed in the right order. A recent article discussed the potential of ATR-FTIR spectroscopy to monitor obesity from the triglyceride spectral band located around 1730 cm−1 [43]. The adipose tissue samples were obtained from 10 weeks old male control (DBA/2 J) (n = 6) and four different obese BFMI mice lines (n = 6 per group). As seen from Figure 3, successful discrimination of the obese, obesity-related insulin resistant and control groups was achieved with high sensitivity and specificity. Obesity might alter the electric activity in brain areas triggering appetite and craving. A drop of liquid is sandwiched, using suitable spacer, between two IR windows that are then mounted in a cell holder. Applications of IR spectroscopic techniques allow identifying molecular changes due to obesity, to understand the molecular mechanism of the disease, to identify specific spectral biomarkers that can be used in diagnosis. Infrared spectroscopy is an absorption technique that uses the infrared portion of the electromagnetic spectrum. For COS analysis, in IR spectroscopy, the absorption peak at 3416.33 cm−1 belonged to O-H and N-H stretching vibrations, 2922.80 cm−1 corresponding to a C-H stretching vibration, and 1566.70 cm−1 originated from -NH2 absorption peak were used. The shift in the position of the amide I band and ratio of the amide I to amide II give information about the variations in protein secondary structure [22]. The disk thickness is important; thin disks are fragile and difficult to handle, while thick disks transmit too little radiation. essentially a graph plotted with the infrared light absorbed on the Y-axis Stimulating increased thermogenic activity in adipose tissue is an important biological target for obesity treatment. There are supervised and unsupervised methods in multivariate analysis. ATR is accepted to require little or no sample preparation, and is one of the most versatile sampling techniques. [80] used FTIR microspectroscopy coupled with chemometrics to monitor and discriminate biomolecular changes due to the anti-adipogenesis effect of baicalein on adipogenesis in 3 T3-L1 cells. The crystals used in ATR cells are made from materials that have low solubility in water and are of a very high refractive index. IR spectra of two enatiomeric compound are identical. Rsad2, which may modulate lipid droplet contents and lipid biosynthesis, and Colec11, which may play a role in apoptotic cell clearance and maintenance of adipose tissue were suggested as potential quantitative trait candidate genes. A.S. Gilbert, in Encyclopedia of Spectroscopy and Spectrometry (Third Edition), 2017. In addition, these spectral biomarkers can be used to identify the appropriate drugs and their doses for treatment. Paint, ink, sweat, fuels, and hair are all examples of substances that can be identified this way. The relationship between the spectroscopy-predicted and observed levels of steatosis, expressed as percentages of the liver biopsy area, was not linear. There are several issues in obesity area that need to be clarified. Explanation of sensitivity, specificity, positive (true and false), and negative (true and false) values can be found in Severcan et al. So if two compounds have identical IR spectra then both of them must be samples of the same substances. Determination of Molecular structure Other techniques include skinfold thickness, dual energy X-ray absorptiometry, bioelectrical impedance, plethysmography, underwater weighing, computed tomography, and near-IR interactance. White adipose tissue has been organized in different anatomical location as visceral white adipose tissue (VAT) and subcutaneous white adipose tissue (SCAT). Both tissues are capable to store triglycerides [47]. Range of group frequency is 4000-1500 cm-1 while that of finger print region is 1500-400 cm-1. Visceral adiposity has a close relation with obesity-induced insulin resistance. For example, fixed-path length-sealed cells are useful for volatile liquids, but cannot be taken apart for cleaning. ], the microscope can be determined is compared with the standard.! But to computational analyses of the obesity differentiation and characterize obesity between data that. 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