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Structural study of colombian coal by fourier transform infrared spectroscopy coupled to attenuated total reflectance (FTIR-ATR)
Orrego, J.A.;Cabanzo Hernández, R.;Mejía-Ospino, E.;
Revista mexicana de física , 2010,
Abstract: the most important colombian coals were studied using attenuated total reflectance-fourier transform infrared (atr-ftir) spectroscopy. the atr-ftir spectra were used to obtain structural parameters of coal and correlating these structural parameters with the rank of the coal. the structural parameters, methylene-methyl ratio (ch2/ch3), aromaticity factor (f α), aliphatic-aromatic ratio (hal /har) were determined directly from the atr-ftir spectra and fα was evaluated from spectra data and an elemental analysis in coals studied here. the aliphatic and aromatic regions were considered between 3000 - 2800 cm-1 and 912 - 670 cm-1, respectively.
Effect of Temperature on the Molecular Weight Distribution in the Different Ranks of Coal during the On-Line Investigation of Coal Pyrolysis Gas Using Direct Photoionization Mass Spectroscopy  [PDF]
Makhosazana Mthembu, Ralf Zimmermann, Thorsten Streibel, Martin Sklorz
International Journal of Clean Coal and Energy (IJCCE) , 2015, DOI: 10.4236/ijcce.2015.44007
Abstract: Coal pyrolysis gas from different ranks of coal was monitored on real time basis using photoionization mass spectroscopy. The molecular weight distribution of different products as a function of temperature from various coal ranks studied was observed. It was noted that the release of different classes of compounds like phenols, alkenes, alkylated aromatics and aromatic skeletons was temperature dependent. For all the coal ranks at lower temperatures phenols were the main component, with alkenes and alkylated aromatics at slight higher temperatures and aromatic skeletons were released at the highest temperatures studied.
Investigation of the Potential of Near Infrared Spectroscopy for the Detection and Quantification of Pesticides in Aqueous Solution  [PDF]
Aoife A. Gowen, Yutaro Tsuchisaka, Colm O’Donnell, Roumiana Tsenkova
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.228124
Abstract: This research investigates the potential of near infrared spectroscopy (NIRS) for the detection and quantification of pesticides in aqueous solution. Standard solutions of Alachlor and Atrazine (ranging in concentration from 1.25 - 100 ppm) were prepared by dilution in a Methanol/water solvent (1:1 methanol/water (v/v)). Near infrared transmission spectra were obtained in the wavelength region 400 - 2500 nm; however, the wavelength regions below 1300 nm and above 1900 nm were omitted in subsequent analysis due to the poor signal repeatability in these regions. Partial least squares analysis was applied for discrimination between pesticide and solvent and for prediction of pesticide concentration. Limits of detection of 12.6 ppm for Alachlor and 46.4 ppm for Atrazine were obtained.
Investigation of protein–protein interactions by isotope?edited Fourier transformed infrared spectroscopy  [PDF]
Tiansheng Li
Spectroscopy: An International Journal , 2004, DOI: 10.1155/2004/173460
Abstract: Recent advance in FTIR spectroscopy has shown the usefulness of 13C uniform isotope labeling in proteins to study protein–protein interactions. 13C uniform isotope labeling can significantly resolve the spectral overlap in the amide I/I′ region in the spectra of protein–protein complexes, and therefore allows more accurate determination of secondary structures of individual protein component in the complex than does the conventional FTIR spectroscopy. Only a limited number of biophysical techniques can be used effectively to obtain structural information of large protein–protein complex in solution. Though X?ray crystallography and NMR have been used to provide structural information of proteins at atomic resolution, they are limited either by the ability of protein to crystallize or the large molecular weight of protein. Vibrational spectroscopy, including FTIR and Raman spectroscopies, has been extensively employed to investigate secondary structures and conformational dynamics of protein–protein complexes. However, significant spectral overlap in the amide I/Iʹ region in the spectra of protein–protein complexes often hinders the utilization of vibrational spectroscopy in the study of protein–protein complex. In this review, we shall discuss our recent work involving the application of isotope labeled FTIR to the investigation of protein–protein complexes such as cytokine–receptor complexes. One of the examples involves G?CSF/receptor complex. To determine unambiguously the conformations of G?CSF and the receptor in the complex, we have prepared uniformly 13C/15N isotope labeled G?CSF to resolve its amide Iʹ band from that of its receptor in the IR spectrum of the complex. Conformational changes and structural stability of individual protein subunit in G?CSF/receptor complex have then been investigated by using FTIR spectroscopy (Li et al., Biochemistry 29 (1997), 8849–8859). Another example involves BDNF/trkB complex in which 13C/15N uniformly labeled BDNF is complexed with its receptor trkB (Li et al., Biopolymers 67(1) (2002), 10–19). Interactions of 13C/15N uniformly labeled brain?derived neurotrophic factor (BDNF) with the extracellular domain of its receptor, trkB, have been investigated by employing FTIR spectroscopy. Conformational changes and structural stability and dynamics of BDNF/trkB complex have been determined unambiguously by FTIR spectroscopy, since amide I/Iʹ bands of 13C/15N labeled BDNF are resolved from those of the receptor. Together, those studies have shown that isotope edited FTIR spectroscopy can be successfully applied to the determination of protein secondary structures of protein complexes containing either the same or different types of secondary structures. It was observed that 13C/15N uniform labeling also affects significantly the frequency of amide IIʹ band, which may permit the determination of hydrogen–deuterium exchange in individual subunit of protein–protein complexes.
Far- and mid-infrared spectroscopy of complex organic matter of astrochemical interest: coal, heavy petroleum fractions, and asphaltenes  [PDF]
F. Cataldo,D. A. Garcia-Hernandez,A. Manchado
Physics , 2012, DOI: 10.1093/mnras/sts558
Abstract: The coexistence of a large variety of molecular species (i.e., aromatic, cycloaliphatic and aliphatic) in several astrophysical environments suggests that unidentified IR emission (UIE) occurs from small solid particles containing a mix of aromatic and aliphatic structures (e.g., coal, petroleum, etc.), renewing the astronomical interest on this type of materials. A series of heavy petroleum fractions namely DAE, RAE, BQ-1, and asphaltenes derived from BQ-1 were used together with anthracite coal and bitumen as model compounds in matching the band pattern of the emission features of proto-planetary nebulae (PPNe). All the model materials were examined in the mid-infrared (2.5-16.7 um) and for the first time in the far-infrared (16.7-200 um), and the IR bands were compared with the UIE from PPNe. The best match of the PPNe band pattern is offered by the BQ-1 heavy aromatic oil fraction and by its asphaltenes fraction. Particularly interesting is the ability of BQ-1 to match the band pattern of the aromatic-aliphatic C-H stretching bands of certain PPNe, a result which is not achieved neither by the coal model nor by the other petroleum fractions considered here. This study shows that a new interesting molecular model of the emission features of PPNe are asphaltene molecules which are composed by an aromatic core containing 3-4 condensed aromatic rings surrounded by cycloaliphatic (naphtenic) and aliphatic alkyl chains. It is instead shown the weakness of the model involving a mixture of PAHs for modeling the aromatic IR emission bands. The laboratory spectra of these complex organic compounds represent a unique data set of high value for the astronomical community; e.g., they may be compared with the Herschel Space Observatory spectra (~51-220 um) of several astrophysical environments such as (proto-) PNe, H II regions, reflection nebulae, star forming galaxies, and young stellar objects.
Investigation of carriers of lustrous carbon at high temperatures by infrared spectroscopy (FTIR)  [PDF]
M. Holtzer,A. Bobrowski,B. Grabowska,S. Eichholz
Archives of Foundry Engineering , 2010,
Abstract: Lustrous carbon is very important in processes of iron casting in green sand. Lustrous carbon (pirografit) is a microcrystalline carbon form, which evolves from a gaseous phase. In the case of applying additions, generating lustrous carbon, for sands with bentonite, there is always a danger of emitting – due to a high temperature of liquid cast iron and a humidity - compounds hazardous for a human health. There can be: CO, SO2, benzene, toluene, ethylbenzene, xylene (the so-called: BTEX) as well as polycyclic aromatic hydrocarbons(PAHs). In order to asses the selected mixtures: bentonite – carrier of lustrous carbon, in which a coal dust fraction was limited, thethermogravimetric analysis and the analysis of evolving gases were performed. Examinations were carried out in the ApplictaionsLaboratory NITZSCH-Ger tebau GmbH ,Selb/Bavaria, Germany. The NETZSCH TG 209 F1 Iris thermal analyzer coupled to the BRUKER Optics FTIR TENSOR(TM) was used to measure.
Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging  [PDF]
Giorgia Agresti,Giuseppe Bonifazi,Luca Calienno,Giuseppe Capobianco,Angela Lo Monaco,Claudia Pelosi,Rodolfo Picchio,Silvia Serranti
Journal of Spectroscopy , 2013, DOI: 10.1155/2013/380536
Abstract: The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to artificial irradiation in a Solar Box. Colour changes were monitored with a reflectance spectrophotometer. Surface chemical modifications were evaluated by measuring the infrared spectra. Hyperspectral imaging was also applied to study the surface wood changes in the visible-near infrared and the short wave infrared wavelength ranges. The data obtained from the different techniques were compared to find the possible correlations in order to evaluate the applicability of the Hyperspectral imaging to investigate wood modifications in a non-invasive modality. The study of colour changes showed an important variation due to photo-irradiation which is the greatest change occurring within the first 24 hours. Infrared spectroscopy revealed that lignin degrades mainly in the first 48 hours. Concerning Hyperspectral imaging, the spectral features in the visible-near infrared range are mainly linked to the spectral shape, whereas in the short wave infrared cellulose and lignin affect shape and reflectance levels. The proposed approach showed that a correlation can be established between colour variation and wood degradation in the visible-near infrared range; furthermore in the short wave infrared region surface chemical changes can be assessed. 1. Introduction The focus of this work is to study the surface modifications of poplar (Populus spp.) wood by reflectance spectrophotometry, Fourier Transform Infrared (FT-IR) spectroscopy, and Hyper Spectral Imaging (HSI) in order to understand the mechanisms that cause the changes and to suggest possible solutions to avoid the degradation phenomena. The choice of poplar was due to its widespread use in Italy for the creation of statues, ceilings, furniture, doors, painted panels, and so forth. In cultural heritage the monitoring of wood surfaces during light exposure should be performed through nondestructive methods to avoid the paradox of damaging a work of art while monitoring its preservation state [1, 2]. For this reason colour measurements were chosen as a possible method to evaluate wood surface changes. Since colour changes on wood surfaces are due to photo degradation of its chemical constituents, the study of the relationship between CIELAB colour changes and changes in chemical composition due to irradiation is of practical importance both in cultural heritage and in contemporary artefacts and objects [3]. This work starts from previous studies, developed by the same authors of this paper, regarding colour
Investigation of Prefrontal Cortex Activity in University Students with Presenteeism: A Near-Infrared Spectroscopy (NIRS) Study  [PDF]
Masateru Matsushita, Schuhei Yamamura, Manabu Ikeda
Journal of Behavioral and Brain Science (JBBS) , 2015, DOI: 10.4236/jbbs.2015.59034
Abstract: Presenteeism refers to impaired performance attributed to attending work with health problems. There has been no study examining the state of presenteeism with objective measures. We compared cerebral hemodynamic changes, measured by near-infrared spectroscopy (NIRS), during neuropsychological tests conducted by university students with presenteeism and healthy controls. Twenty-two university students participated in the study; 11 of them with impaired performance caused by mental health problem were allocated to the presenteeism group and 11 without health problems to the control group. Presenteeism was assessed by the Presenteeism Scale for Students. To evoke hemodynamics changes, the participants completed a Word Fluency Test (WFT) and a Trail Making Test (TMT). The NIRS probes were located over the bilateral prefrontal area. Students with presenteeism had significantly higher incidences of depression than controls. However, there was no significant difference in behavioral performance examinations between the two groups. With regard to hemodynamics changes, the repeated measures analysis of covariance of the NIRS signals revealed significant interactions between group and task activation. Although we observed a significant increase in oxygenated hemoglobin concentration during the WFT among controls (simple main effect; left channel, F(1, 19) = 27.34, P < 0.001; right channel, F(1, 19) = 22.05, P < 0.001), no changes were found in students with presenteeism during either the WFT (simple main effect; left channel, F(1, 19) = 0.12, P < 0.732; right channel, F(1, 19) = 0.08, P < 0.778) or TMT tasks (left channel, t = ﹣0.94, P with Bonferroni correction = 0.745; right channel, t = ﹣2.19, P with Bonferroni correction < 0.113). This is the first study to reveal differences in activity in the cerebral cortex associated with presenteeism. The fact that students with presenteeism have prefrontal dysfunction might reinforce the concept of presenteeism.
Probing Brain Oxygenation with Near Infrared spectroscopy, the Role of Carbon Dioxide and Blood Pressure  [PDF]
Alexander Gersten
Physics , 2015,
Abstract: The fundamentals of near infrared spectroscopy (NIRS) are reviewed. Among the major factors controlling the cerebral blood flow (CBF), the effect of PaCO2 is peculiar in that it violates autoregulatory CBF mechanisms and allows to explore the full range of the CBF. A simple physical model, with a four parameter formula, relating the CBF to PaCO2 is presented. It can be used to transform the fits of one animal to the fits of another one. It enable the use of rats data as monkeys data simply by rescaling the PaCO2 values and the CBF data. Controlled breathing can change the PaCO2. Experiments on human subjects relating the PaCO2 to rSO2, measured with brain oximeters, are presented. A simple model relating the mean blood pressure to CBF is worked out.
The Role of Visible and Infrared Spectroscopy Combined with Chemometrics to Measure Phenolic Compounds in Grape and Wine Samples  [PDF]
Daniel Cozzolino
Molecules , 2015, DOI: 10.3390/molecules20010726
Abstract: The content of phenolic compounds determines the state of phenolic ripening of red grapes, which is a key criterion in setting the harvest date to produce quality red wines. Wine phenolics are also important quality components that contribute to the color, taste, and mouth feel of wines. Spectroscopic techniques (e.g., near and mid infrared) offer the potential to simplify and reduce the analytical time for a range of grape and wine analytes. It is this characteristic, together with the ability to simultaneously measure several analytes in the same sample at the same time, which makes these techniques very attractive for use in both industry and research. The objective of this mini review is to present examples and to discuss different applications of visible (VIS), near infrared (NIR) and mid infrared (MIR) to assess and measure phenolic compounds in grape and wines.
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