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A Report on Growth And Spectroscopic Studies on The L-Tartaric Acid Doped Potassium Dihydrogen Phosphate Non-Linear Optical Single Crystals
摘要： In recent years study of non-linear optical (NLO) materials is gaining rapid momentum due to their needs in several device applications. Potassium Dihydrogen Phosphate (KDP) is a well-known NLO material, whose non-linearity is enhanced by doping with amino acids. In this present study, single crystal of L-Tartaric acid doped potassium Dihydrogen phosphate (LTKDP) have been grown by slow evaporation method at room temperature. Good quality transparent crystals were obtained with 27-30 days. The crystallinity and cell parameters were characterized by X-ray diffraction analysis (XRD), the shifts in frequency assignments of various functional groups of KDP due to the addition of L-Tartaric acid was analysed by Fourier transform infrared (FTIR) and Fourier transform Raman spectroscopic studies. The dielectric constant and the dielectric loss of the single crystals were studied as a function of frequency. Kurtz- Perry power technique was employed to determine the Second Harmonic Generation (SHG) efficiency of LTKDP single crystal.
关键词： X-ray diffraction,SHG efficiency,L-Tartaric acid,slow evaporation method,FT-Raman,Potassium Dihydrogen Phosphate,FTIR,non-linear optical materials
更新于2025-09-23 15:19:57
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Microwave-Induced Structural Changes in Bacteriorhodopsin: Studies by Optical and Fourier Transform Infrared Difference Spectroscopy
摘要： Using optical and Fourier transform infrared (FTIR) difference spectroscopy, microwave radiation was found to affect the bacteriorhodopsin (BR) structure in films at a 30% relative humidity. This study is the first to demonstrate that a transition from the dark-adapted basal state BR560 to a state similar to the light-adapted state BR568, which is a mixture of BR568 and other isomeric forms, occurs in the absence of external photoexcitation on exposure to microwave radiation with a frequency range of 8 ≤ f ≤ 18 GHz and an intensity lower than 10 mW/cm2. The initial response of dark-adapted BR to microwave radiation included collective motion of a large portion of protein atoms, producing relatively strong signals in the regions 3700–3300, 2400–2300, and 800–600 cm–1 of the FTIR difference spectrum. Relatively weak amplitude responses were detected in the frequency range characteristics of the retinal chromophore and amide bands (Amide I and Amide II). The effects reflected changes in the retinal chromophore structure and local changes in the chromophore microenvironment.
关键词： FTIR difference spectroscopy,microwave radiation,bacteriorhodopsin,dark–light adaptation,biological effect,optical spectroscopy
更新于2025-09-19 17:15:36
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Synchrotron infrared spectral regions as signatures for foodborne bacterial typing
摘要： Fourier-transform infrared (FTIR) spectroscopy has emerged as a viable alternative to biochemical and molecular biology techniques for bacterial typing with advantages such as short analysis time, low cost and laboratorial simplicity. In this study, synchrotron radiation-based FTIR (SR-FTIR) spectroscopy with higher spectral quality was successfully applied to type 16 foodborne pathogenic bacterial strains. Combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA), we found that the specific spectral region 1300–1000 cm-1, which reflects the information of phosphate compounds and polysaccharides, can be used as the signature region to cluster the strains into groups similar with genetic taxonomic method. These findings demonstrated that FTIR spectra combined with HCA have a great potential in quickly typing bacteria depending on their biochemical signatures.
关键词： FTIR,PCA,Bacterial typing,Spectral signature,HCA,Synchrotron radiation
更新于2025-09-19 17:15:36
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A combination of portable non-invasive techniques to study on reverse glass paintings at Mistretta museum
摘要： Reverse painting on glass is an old decorative technique used since the Roman time consisting in applying a cold paint layer on the reverse side. The Sicilian Regional Museum of forestry and pastoral traditions in Mistretta (Messina, Italy) houses the largest collection of reverse glass paintings in Italy with a total of 195 artworks. The artworks are attributed to the different Italian geographic area from north to south Italy. A combination of non-invasive analysis by using complementary portable spectroscopic instrumentations (mainly XRF and Raman Spectrometers) was applied on some selection of reverse glass paintings. The goal of the work is the characterization of the nature of pigments and of binders used in the realization of the paints. The composition of glasses used as substrate has been also investigated.
关键词： Reverse glass,Portable instrumentation,Raman spectroscopy,TR FTIR,XRF
更新于2025-09-19 17:15:36
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Crystallization and spectroscopic characterizations of binary SrO-B2O3 glasses doped with LiF, NaF, CaF2, or TiO2
摘要： Glasses based on the basic chemical composition of binary strontium borate (SrO 50-B2O350 mol%) together with samples containing dopant (2%) with one of the fluorides (LiF, NaF, CaF2) or TiO2 have been synthesized through the routinely melting and annealing technique. Collective structural, optical, and thermal properties have been measured for the prepared glasses. X-ray diffraction and SEM measurements were carried out for their corresponding glass-ceramics which were synthesized by controlled thermal heat treatment with two-step regime. FT infrared absorption spectra reveal composite vibrational modes in the mid-range 400–1600 cm?1 which are related to the co-presence of both triangular and tetrahedral borate building units in their particular different wavenumber sites. The low dopant level did not make any distinct variations in the IR spectra. X-ray diffraction patterns elucidate the formed crystal phases after crystallization mainly strontium metaborate and other related borate phase and the LiF shows no distinct variation while NaF2 and CaF2 induce the formation of additional crystalline Na-containing or Ca-containing phases besides the formation of NaF or fluorite (CaF2). TiO2 acts as a nucleating agent and also separate as rutile. The crystallization behavior has been correlated with the assumption of the tendency of SrO to induce phase separation in the host binary borate glass and controlled heat treatment initiates the separation of strontium metaborate crystalline phase in the base binary SrO-B2O3 in accordance with its composition and the role of dopants is found to be varying with the type of dopant. The measured thermal expansion parameters of the prepared glasses reveal variations in their values for transformation and softening temperatures depending on the type of added dopant. The changes in the thermal expansion coefficients in the different parts of the thermal curves are related to the ability of the network to absorb lattice expansion through bending of the bonds. The uniform observed ultraviolet absorption bands are related to traces of iron (Fe3+) ions present as impurities.
关键词： LiF,CaF2,NaF,Thermal expansion,FTIR optical spectra,SrO.B2O3 glass,Glass-ceramics,TiO2
更新于2025-09-19 17:15:36
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Different hydrogen bonding environments of the retinal protonated Schiff base control the photoisomerization in channelrhodopsin-2
摘要： The first event of the channelrhodopsin-2 (ChR2) photocycle, i.e. trans-to-cis photoisomerization, is studied by means of quantum mechanics/molecular mechanics, taking into account the flexible retinal environment in the ground state. By treating the chromophore at the ab initio multiconfigurational level of theory, we can rationalize the experimental findings based on pump–probe spectroscopy, explaining the different and more complex scenario found for ChR2 in comparison to other rhodopsins. In particular, we find that depending on the hydrogen bonding pattern, different excited states are involved, hence making it possible to suggest one pattern as the most productive. Moreover, after photoisomerization the structure of the first photocycle intermediate, P500, is characterized by simulating the infrared spectrum and compared to available experimental data. This was obtained by extensive molecular dynamics, where the chromophore is described by a semi-empirical method based on density functional theory. The results clearly identify which counterion is responsible for accepting the proton from the retinal Schiff base: the side chain of the glutamic acid E123.
关键词： FTIR spectroscopy,quantum mechanics/molecular mechanics,retinal Schiff base,photoisomerization,channelrhodopsin-2,hydrogen bonding,excited states,molecular dynamics
更新于2025-09-19 17:15:36
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Studies on As-synthesized Graphene Oxide Flakes
摘要： Background: Due to the single atomic layer, flexible material, easily tuned of band gap, easily reduced to reduced graphene oxide, graphene oxide (GO) have a lot of application for Electronics, Biosensors, Biomedical application. Objective: The goal of the present work is to study the electrochemical properties of graphene oxide flakes. Method: In the present work, we synthesis of graphene oxide using modified hummer techniques. The morphological and structural characterization of as-prepared GO was investigated with the help of XRD, SEM, FTIR, UV, CV. Results: The XRD patterns of As-prepared graphene oxide (GO) flakes shows a peak at 11.2°, and the calculated value of lattice parameter comes out to be 15.56 A°. The peaks in the Raman spectrum are observed at 1599 cm-1 and 1349 cm-1, which confirms the lattice distortion in the graphene oxide (GO). The peaks in the FTIR spectrum of graphene oxide (GO) observed at, 3636 cm-1, 1753 cm-1, 1649 cm-1, 1456 cm-1, and 1177 cm-1 are attributed to O-H, C=O, C=C, C-OH, C-O bonds, respectively. The electrochemical studies of graphene oxide (GO) modified ITO electrode shows an improvement in the electrochemical parameters. Conclusion: We have prepared the graphene oxide by modified Hummers method. According to the electrochemical studies, graphene oxide (GO) modified ITO electrode is an excellent medium for the fast electron transfer between an electrode surface and electrolyte. On the basis of these studies, it is suggested that graphene oxide may be a best material for the fabrication of biosensors.
关键词： electrochemical studies,FTIR spectrum,Graphene oxide,raman spectrum,Biosensors,Biomedical application
更新于2025-09-19 17:15:36
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Biochemical Changes in Irradiated Oral Mucosa: A FTIR Spectroscopic Study
摘要： Radiation exposure during the course of treatment in head and neck cancer (HNC) patients can induce both structural and biochemical anomalies. The present study is focused on utilizing infrared imaging for the identification of the minor biochemical alterations in the oral mucosa. Chemical maps generated using glycoprotein band indicates its differential distribution along the superficial layer. Spectra extracted from this layer suggests changes in overall nucleic acid and protein content in response to the therapeutic irradiation. Discrimination among control and irradiated groups have been achieved using principal component analysis. Findings of this preliminary study further support prospective utilization of Fourier Transform InfraRed (FTIR) imaging as a non-destructive, label-free tool for objective assessment of the oral mucosa in patient groups with or without radiation therapy.
关键词： radiotherapy,head and neck cancer,FTIR spectroscopy
更新于2025-09-19 17:15:36
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Zn2SnO4 QDs decorated Bi2WO6 nanoplates for improved visible-light-driven photocatalytic removal of gaseous contaminants
摘要： Zn 2 SnO 4 quantum dots (QDs) decorated Bi 2 WO 6 nanocomposites were prepared via a two-step hydrothermal reaction progress. The Zn 2 SnO 4 QDs were highly dispersed onto the surface of plate-shaped n-type Bi 2 WO 6 , which allows more photons to be harvested and effectively improve the separation and utilization efficiencies of photoinduced electrons and holes due to the formation of heterojunction. Among them, 3% Zn 2 SnO 4 QDs/Bi 2 WO 6 nanocomposite showed the highest photocatalytic performance (95.5% of acetone degradation), compared with other different amounts of Zn 2 SnO 4 QDs, which are 5.86 and 1.99 times higher than those of pure Bi 2 WO 6 , respectively. Meanwhile, the hybridized sample was investigated by four successive photocatalytic degradation of acetone under visible light, displaying great photo-stability. Furthermore, through in-situ FTIR, acetaldehyde, acetic acid and formaldehyde were certified as intermedias during the photocatalytic degradation of acetone. Based on these results, the relationship between photocatalytic activity and the formation of Zn 2 SnO 4 QDs/Bi 2 WO 6 heterojunction is further discussed and the possible reaction mechanism is proposed. Such novel photocatalyst as visible light responsive catalyst provides a new choice for the efficient degradation of contaminants.
关键词： Acetone,Nanocomposites,Zn 2 SnO 4 QDs/Bi 2 WO 6,In-suit FTIR
更新于2025-09-19 17:15:36
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Deep learning for FTIR histology: leveraging spatial and spectral features with convolutional neural networks
摘要： Current methods for cancer detection rely on tissue biopsy, chemical labeling/staining, and examination of the tissue by a pathologist. Though these methods continue to remain the gold standard, they are non-quantitative and susceptible to human error. Fourier transform infrared (FTIR) spectroscopic imaging has shown potential as a quantitative alternative to traditional histology. However, identification of histological components requires reliable classification based on molecular spectra, which are susceptible to artifacts introduced by noise and scattering. Several tissue types, particularly in heterogeneous tissue regions, tend to confound traditional classification methods. Convolutional neural networks (CNNs) are the current state-of-the-art in image classification, providing the ability to learn spatial characteristics of images. In this paper, we demonstrate that CNNs with architectures designed to process both spectral and spatial information can significantly improve classifier performance over per-pixel spectral classification. We report classification results after applying CNNs to data from tissue microarrays (TMAs) to identify six major cellular and acellular constituents of tissue, namely adipocytes, blood, collagen, epithelium, necrosis, and myofibroblasts. Experimental results show that the use of spatial information in addition to the spectral information brings significant improvements in the classifier performance and allows classification of cellular subtypes, such as adipocytes, that exhibit minimal chemical information but have distinct spatial characteristics. This work demonstrates the application and efficiency of deep learning algorithms in improving the diagnostic techniques in clinical and research activities related to cancer.
关键词： tissue classification,spatial features,convolutional neural networks,deep learning,spectral features,FTIR histology
更新于2025-09-19 17:15:36