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ATR-FTIR spectroscopy to study the effects of laser irradiation in bone tissue
摘要： The use of lasers on bone cut can provide a series of advantages for both the surgeon and the patient. However, for a safe and efficient application it is necessary to know the exact effects that the laser causes in the bone tissue. The aim of this work was to study the effects of Er,Cr:YSGG irradiation in bone tissue using the ATR-FTIR technique. Pieces of tibia rabbit bone were divided in six groups with three samples per group. In one of the groups the samples did not undergo any treatment; in the others the samples were laser irradiated with different energy densities. The infrared spectra acquisition was made using an ATR accessory. For a semi-quantitative analysis, the area under each band was calculated and normalized by the phosphate band area of the same spectrum. The results showed a gradual material loss as the energy density increased in the bands of water, amide I, and carbonate, amide II, amide II and collagen. This is probably caused by the temperature rise due to laser irradiation. These results are the first steps in testing the Er,Cr:YSGG laser efficacy as a cutting tool, a pivotal aspect of its consolidation in clinical procedures.
关键词： laser,FTIR,bone
更新于2025-09-16 10:30:52
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Jet-cooled rovibrational spectroscopy of methoxyphenols using two complementary FTIR and QCL based spectrometers
摘要： Methoxyphenols (MPs) are a significant component of biomass burning emissions which mainly exists in our atmosphere in the gas phase where they contribute to the formation of secondary organic aerosols (SOAs). Rovibrational spectroscopy is a promising tool to monitor atmospheric MPs and infer their role in SOA formation. In this study, we bring a new perspective on the rovibrational analysis of MP isomers by taking advantage of two complementary devices combining jet-cooled environments and absorption spectroscopy: the Jet-AILES and the SPIRALES setups. Based on Q-branch frequency positions measured in the Jet-AILES Fourier-transform infrared (FTIR) spectra and guided by quantum chemistry calculations, we propose an extended vibrational and conformational analysis of the different MP isomers in their fingerprint region. Some modes such as far-IR out-of-plane –OH bending or mid-IR in-plane –CH bending allow us to assign individually all the stable conformers. Finally, using the SPIRALES setup with three different external cavity quantum cascade laser sources centered on the 930–990 cm?1 and the 1580–1690 cm?1 ranges, it was possible to proceed to the rovibrational analysis of the ν18 ring in-plane bending mode of the MP meta isomer providing a set of reliable excited state parameters, which confirms the correct assignment of two conformers. Interestingly, the observation of broad Q-branches without visible P- and R-branches in the region of the C–C ring stretching bands was interpreted as being probably due to a vibrational perturbation. These results highlight the complementarity of broadband FTIR and narrowband laser spectroscopic techniques to reveal the vibrational conformational signatures of atmospheric compounds over a large infrared spectral range.
关键词： SPIRALES,Jet-AILES,methoxyphenols,FTIR,vibrational perturbation,conformational analysis,rovibrational spectroscopy,QCL
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Breath Signatures of Cerebral Palsy Patients Revealed with Mid-Infrared FTIR Spectroscopy
摘要： In the absence of “broadband” objective medical diagnostics, photonics technologies are now considered as a promising way to establish it. For example, being applied to human breath, under right conditions they should allow for unambiguous identification of metabolites circulating in blood and released in lungs alveoli as volatile organic compounds (VOCs). Nowadays, tremendous progress is achieved in developing laser-based mid-infrared spectrometers highly sensitive to VOCs [1,2]. Still, the spectral range covered by the laser spectrometers demonstrated so far, and signal-to-nose ratio (SNR) are not superior to conventional FTIR spectrometers based on thermal source. A significant amount of water vapour in breath is another, though general for all techniques, severe problem for VOCs detection. In addition to the detection, data analysis should be advanced in order to accurately compare healthy and diseased cohorts under study.
关键词： cerebral palsy,FTIR spectroscopy,mid-infrared spectroscopy,breath analysis,VOCs
更新于2025-09-16 10:30:52
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Microstructure Investigation of He<sup>+</sup>- Implanted and Post-Implantation-Annealed 4H-SiC
摘要： Microstructure damage and evolution in 4H-SiC under He-ion implantation and post-annealing have been investigated by the combination of fourier transform infrared spectrometer (FTIR), Raman scattering spectroscopy and high resolution X-ray diffractometer (HRXRD). After implantation, the 4H-SiC specimen exhibits a heavy damage and some amorphous state appear. With increasing annealing temperature, to some extent recovery in damaged lattices was observed, as a result of the peaks of Raman and HRXRD regain their intensities. However, the reverse annealing behavior in damaged peaks was displayed after annealed at 973K. This reverse annealing effect was revealed to be due to the formation and the growth of He bubbles above 973K.
关键词： HRXRD,SiC,FTIR,He-ion implantation,Annealing,Raman
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Do Infrared Molecular Fingerprints of Individuals Exist? Lessons from Spectroscopic Analysis of Human Blood
摘要： Genetic, lifestyle and environmental factors, along with development and aging impact molecular composition of human blood. Although many diseases leave their trace in blood, the question is whether this trace can be robustly and reproducibly measured and used for health monitoring of a given adult population. Infrared molecular spectra of blood serum can be obtained in a non-invasive, time- and cost-efficient manner, delivering molecular information from all molecular species within the highly complex samples. We demonstrate that broadband infrared spectroscopy can be used for reproducible molecular fingerprinting of human blood. To evaluate whether certain medium is sufficiently robust to facilitate detection of disease onset, the quantitative extent of variability of a person as well as a reference population needs to be evaluated. If within-person variability would exceed that of the between-personal variability in a reference population, the approach would not be suited for disease detection. To assess the extent of uniqueness of infrared molecular fingerprints as well as their biological variability, we performed a comprehensive prospective longitudinal study collecting blood samples of 27 healthy individuals donating blood at 8 consequent intervals. We apply broadband infrared molecular fingerprinting by Fourier transform infrared spectroscopy (FTIR) and analyse between-person and within-person variability based on all different molecular classes in the blood simultaneously. We report experimental evidence of the feasibility of identifying a person within a group of individuals based on her/his infrared molecular fingerprint, similarly to metabolic fingerprints [1]. In a first step, using standard methods for descriptive analysis we observe that the between-person variability is larger than the within-person variability by a factor of 3 (Fig.1 Left). This observation opens up the possibility for disease detection. In a second step, we combine standard dimensionality-reduction methods, such as principal component analysis (PCA), and several high-accuracy machine-learning algorithms [1] (random forests, extreme gradient boosting, k nearest neighbours) for deriving classification rules, which we then use for making predictions on test sets of unseen data. For a group of 7 donations that span a period of 6 weeks, we reach peak classification accuracy of above 95% (Fig.1 Right), while the accuracy of a classifier predicting in random would have been as low as 3.7%. In addition, we evaluate the underlying spectral features with respect to their importance on signalling separation and in this way identifying the human blood serum constituents associated with between-person variation. Observed robustness of infrared molecular fingerprints suggests their applicability for health and treatment monitoring.
关键词： infrared molecular fingerprints,FTIR,health monitoring,human blood,spectroscopic analysis
更新于2025-09-12 10:27:22
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Dye Aggregation, Photostructural Reorganization and Multiple Concurrent Dye···TiO <sub/>2</sub> Binding Modes in Dye-Sensitized Solar Cell Working Electrodes Containing Benzothiadiazole-Based Dye <b>RK-1</b>
摘要： Dye-sensitized solar cells (DSSCs) are widely considered as a promising contender for the next generation of photovoltaic devices. The light-harvesting component in the DSSCs, i.e., the sensitizers, are adsorbed onto the semiconductor layer to form the photoelectrode that absorbs solar energy and converts it into electrical power. The choice of dye has a profound impact on the DSSC performance. Thus, substantial research efforts have been devoted to the development and testing of a large variety of sensitizers during the past decades. We herein focus our attention on the metal-free benzothiadiazole-based dye 2-cyano-3-(4-(7-(5-(4-(diphenylamino)phenyl)-4-octylthiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl) acrylic acid (RK-1), which exhibits excellent power conversion efficiency and high stability. Simulations and experiments were combined to conduct a systematic study of its optical and structural properties. RK-1 shows a broad absorption band over the visible region and the formation of H aggregates in solution. Deprotonation of the cyanoacrylic acid group in RK-1 occurs upon dye adsorption onto TiO2. This induces a hypsochromic shift of the absorption band. The emission spectrum of RK-1 shows a broad band and a large Stokes shift (6949 cm-1), indicating the presence of several different structural reorganization processes during excitation. Time-dependent density functional theory (TD-DFT) calculations reveal that intramolecular charge transfer in RK-1 molecules should be predominantly attributed to the HOMO-LUMO transition. DFT modeling also reveals the involvement of cyano group in anchoring to TiO2 which makes the dye…TiO2 binding structure more stable. Fourier transform infra-red spectroscopy data prove that bridging bidentate (BB) and COO/CN (A2) binding modes co-exist in the RK-1···TiO2 interfacial structure.
关键词： DSSC dyes,RK-1,FTIR,DFT,TDDFT,binding mode
更新于2025-09-12 10:27:22
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Analysis of the degradation of encapsulant materials used in photovoltaic modules exposed to different climates in China
摘要： This work investigates the degradation mechanisms of polymeric encapsulants used in photovoltaic modules. Two groups of photovoltaic modules, which were exposed to two typical climates, namely a hot-humid climate and a hot-dry climate, were investigated. Both types of modules were produced by Siemens Solar in 1992 and exposed to outdoor sunlight and the climate for 18 years. The results show that, depending on the climate conditions, the polymeric encapsulant materials exhibit different degradation mechanisms regarding the optical, chemical and morphological properties. The aging of polymeric encapsulant materials is, on the one hand, related to the working environment (moisture, sunlight intensity, UV content and temperature) and, on the other hand, also the conditions are not uniform across the modules: moisture ingress is more important at the edge of the module, oxygen diffusion is more important between cells than at the center of a cell, the module temperature is not uniform.
关键词： Photovoltaic module,FTIR spectroscopy,Raman spectroscopy,EVA sample,Degradation behavior
更新于2025-09-12 10:27:22
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Spectroscopic studies on Cr3+ doped ZnCdO nanostructures for optoelectronic device application
摘要： Cr3+ ion doped ZnCdO nanopowder was synthesized by chemical solution method. Structural (X-ray di?raction, surface morphology and energy dispersion), di?erent spectroscopic studies like FT-IR, EPR, Optical and PL were performed on the prepared nanopowders. From the XRD pattern, it was con?rmed that the crystalline size of the nanopowder was at nanoscale range. The morphological surface of the powder was analyzed by SEM. FT-IR showed the trademark assimilation groups identi?ed with the metal oxides and additionally other natural particles. EPR spectrum exhibited characteristic Cr3+ ion resonance signal at g = 1.98. By connecting EPR and optical information, the holding parameters have been resolved. From the optical absorption studies, the assimilation groups are assessed. Photoluminescence studies showed that the out?ow groups are in UV and blue area. These parameters recommended that Cr3+ ions are in octahedral site symmetry with covalent bonding nature.
关键词： Cr3+ ion doped ZnCdO nanopowder,EPR,FTIR,XRD,Optical,PL
更新于2025-09-12 10:27:22
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Ligand Binding-Induced Structural Changes in the M <sub/>2</sub> Muscarinic Acetylcholine Receptor Revealed by Vibrational Spectroscopy
摘要： M2 muscarinic acetylcholine receptor (M2R) is a prototypical G protein-coupled receptor (GPCR) that responds to acetylcholine and mediates various cellular responses in the nervous system. Here, we used Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy analyses on M2R reconstituted in lipid membrane to understand the molecular mechanism behind the ligand binding-induced conformational changes. Upon agonist binding, M2R shows large spectral change of amide-I band corresponding to backbone C=O stretch, which likely connects with the receptor activation in lipid environment. These results pave the way to probe effects of different ligand binding on GPCRs using vibrational spectroscopy.
关键词： ATR-FTIR spectroscopy,GPCR,M2R,Ligand,acetylcholine
更新于2025-09-12 10:27:22
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Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD)
摘要： The present work is focused on spectroscopic study of four samples of Argan wooden artifact pertaining to the 17th, 18th, 20th and 21st centuries. The objective is to characterize their unknown structures by the study of their non degraded parts and to investigate changes occurred in their degraded parts due to the natural degradation process. Attenuated total re?ectance Fourier transform infrared spectroscopy gauges the presence of many functional groups related to cellulose I and/or II (OH, C–O–C and –CH2), hemicelluloses (particularly C?O (cid:2)1), and lignin (OH phenolic, Car-O and C?Car) and provides qualitative information on the state of wood alteration by informing on the evolution of new former C?O bands. The degree of conversion to carbonyl group, especially quinone or p-quinone at 1650 cm (cid:2)1, is correlated to lignin degradation, while the absence of the C?O acetoxy absorption is ascribable to occurred deterioration in hemicelluloses, and (cid:2)1. X-ray diffraction determines the presence of two forms of cellulose; amorphous cellulose at 18.5(cid:3) 2θ and predominant crystalline cellulose Iβ at 2θ ? 22.6(cid:3) which characterized by an intense peak. The decrease of crystallinity index values con?rms the deterioration level and obvious changes in crystallinity level. However, the microcrystalline structure appears unaltered because no signi?cant changes were observed for calculated cristallite seize. The obtained results depend on the prolonged time of ageing, natural deterioration phenomena, and wood part (internal or external) that is exposed to degradation. The combination of these two methods is useful for an accurate estimation of the degradation level of argan wood.
关键词： Chemistry,Argan wood artifact,XRD,Analytical chemistry,Natural product chemistry,Materials Chemistry,Natural degradation,Archaeology,ATR-FTIR spectroscopy,Crystallinity,Lignocelluloses,Structural characterization,Materials Science,Organic chemistry
更新于2025-09-12 10:27:22