Infrared Spectrometry

Propylene oxide (PO) was polymerized by some diphenylzinc ketone systems. Cocatalytic effects of nine ketones were examined. The systems are greatly influenced by the nature of the ketone and by the molar ratio of ketone to diphenylzinc. Methyl and cyclic ketones were the most effective as cocatalyst and the maximum catalyst activity was found, in most cases, for a molar ratio of unity. The difference in cocatalyst activities for methyl ketones is attributed to electronic effects, while steric hindrance is not relevant. Similar effects were found for PO polymerization initiated by diphenylzinc in combination with cyclic and with non-halogenated methyl ketones. However the activity of the diphenylzinc<liethyl ketone system increases with increase of the molar ratio. The diphenylzinc-benzophenone system shows a small dependence on the molar ratio. The activity of the diphenylzinc acetylacetone decreases with increase of the molar ratio showing maximum conversion to polymer when no ketone was added. Polymerization of ethylene oxide by some of these systems showed behaviour similar to that found for PO.

The skeletal structure of aerogel is determined before, during, and after the gel is formed. Supercritical drying of aerogel largely preserves the pore structure that is determined near the time of gelation. To better understand these gel formation mechanisms we carried out measurements of the time evolution of light scattering in a series of gels prepared without conventional acid or base catalysis. Instead, ultraviolet light was used to catalyze the formation of silica gels made from the hydrolysis of tetraethylorthosilicate and partly prehydrolyzed tetraethylorthosilicate in ethanol. Time evolution of light scattering provides information regarding the rate and geometrical nature of the assembly of the primary silica particles formed in the sol. UV-catalyzed gels show volumetric growth typical of acid-catalyzed gels, except when UV exposure is discontinued at the gel point, where gels then show linear chain formation typical of base-catalyzed gels. Long term UV exposure leads to coarsening of the pore network, a decrease in the clarity of the aerogel, and an increase in the surface area of the aerogel. Additionally, UV exposure up to the gel point leads to increased crystallinity in the final aerogel.

In this study, development of cooperative catalyst is demonstrated whereby Lewis acid/base species and nucleophilic parts are immobilized in the pores of a polyamide-imide (PAI) hollow fiber support. The highly solvent-stable and porous Br/APS-grafted ZrO2-PAI hollow fiber (Br/APS/Zr-PAIHF) catalyst was created by crosslinking of bare ZrO2-PAIHF polymer with 3-aminopropyltrimethoxysilane (APS) followed by alkylation with 1,2-dibromoethane at 110 °C. This bifunctional catalyst consists of a porous ZrO2-PAIHF polymer crosslinked with APS that was further immobilized with nucleophilic bromide ions. Porous ZrO2-PAIHF provides a physical barrier to prevent cooperative Lewis acid/base species and nucleophilic parts movement, aggregation, and detachment from the support into the product stream. The performance of Br/APS/Zr-PAIHFs as heterogeneous catalyst was investigated for the reaction of carbon dioxide (CO2) with styrene oxide (SO) which leads to the formation of styrene carbonate (SC). The influence of various reaction parameters including reaction temperature, reaction time, solvents, and CO2 pressure were systematically investigated in detail. Our results indicated that the synergistic cooperative effect of nucleophilic bromide ion (Br-) and Lewis acid/base species on PAIHF supports leads to a maximum SC selectivity of 99.1%. Additionally, SO conversion of 100% and excellent SC selectivity of 98% were obtained over Br/APS/Zr-PAI-HF catalyst.

The combination of the near infrared (NIR) and Fourier-transform infrared (FTIR) absorbance spectra (1100-2500 nm and 4000-600 cm -1 ) of 100 cocoa powder samples was used to build calibration models for the determination of the content of fat, nitrogen, and moisture. The samples that comprised the dataset had an average composition of 13.51% of fat, 3.77% nitrogen, and 3.98% moisture. The fat content ranged from 2.42 to 22.00%, the nitrogen from 0.88 to 4.48%, and moisture from 1.60 to 7.80%. For NIR, the relative root mean square error of cross-validation (RMSECV) was 7.0% (R 2 = 0.96) for fat, 1.7% (R 2 = 0.98) for nitrogen, and 5.2% (R 2 = 0.94) for moisture. For FTIR, the relative RMSECV was 10.4% (R 2 = 0.94) for fat and 3.9% (R 2 = 0.95) for nitrogen. However, for moisture, it was not possible to build a calibration model with suitable predictability. The combination of the NIR and FTIR domains (data fusion) by outer product analysis PLS1 allowed to predict these parameters and to characterise frequencies in one domain based on the information of the other domain. This work allows to conclude that the second derivative of NIR is the recommended procedure to quantify fat, nitrogen, and moisture content in cocoa powders by infrared spectroscopy.

In this investigation, we report facile synthesis of cadmium(II)-thioacetamide nanocomposites in the presence and absence of polyvinyl alcohol under ultrasonic irradiations, using cadmium acetate dihydrate (Cd(CH 3 COO) 2 .2H 2 O), potassium iodide (KI), thioacetamide (TAA, CH 3 CSNH 2 ), and polyvinyl alcohol (PVA) as the starting materials. Results show that in the presence of polyvinyl alcohol sizes of the particles reduce. Characterization of the compounds was carried out by determination of melting point, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FT-IR) spectroscopy, 1 H-NMR spectroscopy and thermogravimetric-differential thermal analyses (TG/DTA). The thermal decomposition of the polymeric nanocomposite, Cd-thioacetamide/PVA in an autoclave under critical condition led to the formation of spherical cadmium sulfide nanoparticles with an average particle size of about 20 nm. The X-ray diffraction pattern at room temperature revealed that highly pure and crystallized CdS with hexagonal structure were obtained. The sonochemical method resulted in a significant reduction of reaction time, reaction temperature and particle size of the products.

Nitrate is an important pollutant found in environmental samples. Nitrate and nitrite pose various environmental as well as health hazards. Different methods of determining nitrate in various environmental samples developed during previous years include spectrohotometric, chemiluminescence, electrochemical detection, chromatographic, capillary electrophoretic, spectrofluorimetric methods. Out of these, methods based on spectroscopic detection of nitrate have been discussed in this review article due to their easy availability, high sensitivity, low detection limit, economical and facile nature. Methods based on spectrophotometry, Raman Spectroscopy, IR and FTIR Spectroscopy, atomic absorption spectroscopy (AAS), fluorescence spectroscopy, chemiluminescence, mass spectroscopy, molecular emission cavity analysis (MECA), electron paramagnetic resonance spectrometry (EPR) and nuclear magnetic resonance spectrocopy (NMR) have been reviewed. The basic principle, detection limits, detection range, RSD%, sample throughput/h, advantages and disadvantages have been discussed.

Fourier transform infrared difference spectroscopy (FTIR) reveals that the Meta II intermediate of the rhodopsin bleaching cascade is structurally distorted relative to rhodopsin. In addition to previously detected alterations in the state of carboxyl groups, a small part of the protein back-bone undergoes a conversion from a-helical to :-type structure. All of these changes partially reverse during Meta II decay. This evidence together with FTIR studies of earlier photointermediates indicates that of the known photointermediates the protein structure of Meta II is the most distorted. It is concluded that light causes rhodopsin to convert into a conformationally distorted form (Meta II), which subsequently refolds into a more rhodopsin-like conformation (opsin).

Natural gas can exist not only in gaseous, but also in liquefied and solid aggregate states. Natural gas in a solid state -gas hydrates of natural gas. It is in the solid state -in the form of gas hydrates -that natural gas can be stored in improved casing gas-resistant structures. In order to improve the pneumatic structures and the method of operation of these structures, the features of such storage are substantiated. The design and operation technology of the ground storage facility for the accumulation and storage of natural gas as part of the gas hydrate includes the main and some auxiliary elements. Compulsory components of a pneumatic structure include a fence, pumping equipment and a foundation. However, the main element of the ground pneumatic structure is a frameless gas-resistant shelter in the form of at least two dome-shaped gas-tight soft shells on a thermally insulated base. A necessary condition for the storage of gas hydrates of natural gas is the creation of thermobaric conditions higher than the dissociation parameters of gas hydrates of this composition. For increase the thermal resistance of the pneumatic coating, it is

KBaPO 4recently reported to hydrate in steam at 80°C into a novel low-temperature protonic conductorwas synthesized by a solid state reaction and its electrical properties characterized by impedance spectroscopy. At high temperatures the conductivity of KBaPO 4 was low (order of 10 -6 S/cm at 600°C) and not significantly different in dry and wet atmospheres, suggesting that KBaPO 4 does not take up and conduct protons to any significant extent under these conditions. It was also independent of oxygen partial pressure and increased by acceptor doping (K excess), suggesting that the transport is ionic and by an effectively positive charge carrying defect. Impedance spectroscopy displayed significant grain boundary series resistance, and the bulk and grain boundaries displayed activation energies of approximately 110 and 120 kJ/mol, respectively. At lower temperatures, the conductivity increased, typical of transport in adsorbed water in a porous sample. Exposure of KBaPO 4 to steam at 80°C resulted in decomposition into Ba 3 (PO 4 ) 2 and a liquid phase, presumably a molten hydrate of K 3 PO 4 . We thus suggest that what literature proposes as protonic conduction in steamed KBaPO 4 in fact represents transport of K + , OH -and HPO 4 2ions in the molten hydrate of the decomposition product K 3 PO 4 held inside porous Ba 3 (PO 4 ) 3 .

Attenuated total reflectance-Fourier transform infrared spectrometry and chemometrics model was used for determination of physicochemical properties (pH, redox potential, free acidity, electrical conductivity, moisture, total soluble solids (TSS), ash, and HMF) in honey samples. The reference values of 189 honey samples of different botanical origin were determined using Association Official Analytical Chemists, (AOAC), 1990; Codex Alimentarius, 2001, International Honey Commission, 2002, methods. Multivariate calibration models were built using partial least squares (PLS) for the measurands studied. The developed models were validated using cross-validation and external validation; several statistical parameters were obtained to determine the robustness of the calibration models: (PCs) optimum number of components principal, (SECV) standard error of cross-validation, (R(2)cal) coefficient of determination of cross-validation, (SEP) standard error of validation, and (R(2)val) coeffi...

Highly periodic hexagonal honeycombs of platinum-germanium chalcogenide and platinumtin selenide frameworks were prepared by linking corresponding [Ge4Q10] 4-(Q ) S, Se) and [Sn4Se10] 4- clusters with Pt 2+ ions. The non-oxidic honeycombs designated as CnPyPtGeQ and CnPyPtSnSe were templated by the lyotropic liquid-crystalline phase of alkylpyridinium surfactant [CnH2n+1NC5H5]Br (CnPyBr) with n) 12, 14, 16, 18, 20, and 22. Although the materials are amorphous at the microscale, they have crystalline mesoporosity with well-ordered and aligned surfactant-filled cylindrical pores. In addition to high mesoscopic order, the pore-pore separation is adjustable with the surfactant chain length (i.e., value of n). The quality of these materials, as judged by the degree of hexagonal order, rivals or exceeds that reported for the highest quality MCM-41 silicates. The materials have the lowest band gap reported so far for mesostructured chalcogenides solids, in the range 1.5 < Eg< 2.3 eV. The CnPyPtGeS analogues show intense photoluminescence at 77 K when excited with light above the band gap.

Aqueous dispersions of demineralized β-lactoglobulin (β-lg) were held at 85 °C for 15 min at a constant protein concentration of 1 wt % in the pH range of 3.0-7.0. This led to denatured protein content ranging from 20% (pH 3.0) to 90% (pH 5.0). The protein aggregates formed were characterized as to their stability to sedimentation (turbidity), morphology, size, surface charge, ANS surface hydrophobicity, and content in accessible thiol groups. Additionally, the changes in secondary structures of the protein upon heating were followed by Fourier transform infrared spectroscopy (FTIR). Stable dispersions (no sedimentation for 10 min) of individualized β-lg microgels were obtained at specific pH 4.6 and 5.8, corresponding to an aggregation yield of about 80%. The width of the pH region leading to these microgels was 0.3 pH unit below or above the two specific pH values. Microgels were characterized by a spherical shape and remarkably low polydispersity in size (<0.2). Their z-average hydrodynamic diameter determined by dynamic light scattering (DLS) was between 160 and 220 nm, and their ζ-potential was +30 or -40 mV, depending on the initial pH before heating. Microgels obtained at pH 4.6 displayed a lower binding capacity for ANS and a lower content of accessible thiol groups as compared to those obtained at pH 5.8. Both types of microgels might therefore differ in their internal and interfacial structures. Between pH 4.6 and 5.8, large sedimenting protein particulates were obtained, whereas soluble aggregates were formed at pH <4.6 or >5.8. Interestingly, DLS experiments showed that before heating, β-lg was mainly present in an oligomeric state at pH 4.6 and 5.8. This result was confirmed by FTIR measurements indicating the stronger contribution of the 1616-1624 cm -1 spectral band corresponding to intermolecular β-sheets in the pH range of 4.0-6.0. Upon heating, FTIR spectroscopy revealed that individualized microgels were obtained under pH conditions where a balance between attractive forces arising from protein unfolding leading to the formation of intermolecular β-sheets (1616-1624 cm -1 band) and the repulsive electrostatic forces due to the initial protein net charge was achieved.

The voltammetric behaviour of tetrafluoroborate salts, acetonitrile solutions, to which hydrogen ions had been added, has been investigated both at platinum and mercury electrodes. It has been established that HBF 4 is unstable in this medium and its decomposition gives HF and BF 3.

The reversed-flow gas chromatography sampling technique, reported earlier, is now used to measure the diffusion coefficient of vapors from a liquid into a carrier gas and at the same time to determine the rate coefficient for the evaporation of the liquid. The mathematical expression describing the elution curves of the sample peaks is derived and used to calculate the above parameters for the liquids n-pentane, n-hexane, n-heptane, n-octane, methanol, ethanol, propan-1-01, butan-1-01, and pentan-1-01 evaporating into the carrier gas helium. The values of diffusion coefficients found are compared with those calculated leads to profound disagreement with the experimental findings. theoretically or reported in the literature. An alternative mathematical analysis based on

n¼99, 1.2%); complete veiling (n¼50, 0.6%); antroliths (n¼9, 0.1%); anterior extension (n¼303, 3.9%); hypoplasia (n¼26, 0.3%) and loss of continuity affecting the maxillary sinus floor (n¼53, 0.6%). The Pneumatization of the maxillary sinus figured as the most prevalent morphologic alteration, while mucosal thickness was the most prevalent pathologic condition. The present study highlights the importance of radiographic knowledge on the morphologic and pathologic alterations of the maxillary sinuses to properly planning and managing maxillofacial procedures Dentistry.

Porous matrix of polyaniline (PANI) has been electrodeposited along with the entrapment of biocompatible redox mediator ferritin (Frt) and glucose oxidase (GOx) on the surface of glassy carbon (GC) electrode. The characterizations have been carried out by Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and Transmission electron microscopy (TEM).

A method was developed for the chromatographic separation and quantification for a mixture of Malathion (as organophosphorus nerve agent), and S-mustard (as blister agent). The method used a high performance liquid chromatography (HPLC) with reversed phase C-18 column, and UV detection at 220 nm. The compounds were separated using isocratic elution acetonitrile-water (50%) at a flow rate of 0.7 mL/min in a period of 5 min. The retention times were (1.939) min for S-mustard and (3.063) min for Malathion. The calibaration curves were linear (R 2 = 0.999) in the studied concentration range (200 to 1000 µg/mL). Sensitivity of the method for quantification of Malathion was found to be higher than that of S-mustard by four times. In addition, the accuracy was found to be (~ 97%) for both.

Many kaolinites are known to exhibit limited intercalation capacity which affects their usage. Some reports have linked this lack of reactivity to particular structural features or to slow kinetics; others recommended increasing intercalation temperature as a remedy. The purpose of the current study was to investigate systematically the N-methylformamide (NMF) intercalation capacity of three kaolinites differing in layer stacking order (KGa-1b, KGa-2, and Imerys Hywite Alum) in the 5–150°C temperature range. Near-infrared spectroscopy (NIR) was employed to record the full kinetics of intercalation in closed systems with excess NMF. Increasing intercalation temperature accelerated the reaction, but the NMF uptake decreased and eventually vanished. Complementary thermogravimetric analysis (TGA) confirmed this unexpected trend. All kaolinites exhibited the same behavior, but the amount of inert material was in the order of their stacking-fault concentration at all temperatures: KGa-2 &...

The first scientific paper on microemulsion was published in 1943 by Schulman and Hoar of Cambridge University. Microemulsion is basically made up of oil, water, surfactant and a short-chain alcohol, acid or amide (called 'cosurfactant'). They were called swollen micelles or by some other names but not microemulsion in 1943 or after. It was rechristened 'microemulsion' in 1959 by Schulman et al. who were then at New York's Columbia University. Research in microemulsion became popular in 1980s when there loomed a large spectre of oil scarcity and its eventual effect on human civilization as we are aware today. Microemulsion was thought to be important for tertiary oil recovery. It has also been found to be useful for nanoparticle synthesis, in pesticide formulation, in drug delivery, and in many other ways, and the research on it still has a great potential and importance. In the 75 year of its innovation (and documentation in the literature), a short but succinct article with its flavour and importance is presented here.

Au(III)-Schiff base complexes are active hydrogenation catalysts, giving turnover frequencies similar to those of the corresponding complexes of Pd(II), which has the same d 8 electronic structure as Au(III). The mechanism of the reaction has been studied in detail by a combination of kinetic experiments and theoretical calculations. It is predicted and tested that the nature of the solvent plays a critical role for the heterolytic cleavage of H2 (controlling step). Taking this into account, and by properly selecting the nature of solid supports (polarity and proton-donating ability), it was possible to strongly increase the activity of the homogeneous Au(III) and Pd(II) catalysts by grafting them onto the surface.

GC-FTIR spectra of 55 nerve agent homologues and dialkyl methylphosphonates have been analyzed. Infrared spectral library searches together with retention index searches have been used for identification of nerve agent homologues and dialkyl methylphosphonates.

Light-activated protein domains provide a convenient, modular, and genetically encodable sensor for optogenetics and optobiology. Although these domains have now been deployed in numerous systems, the precise mechanism of photoactivation and the accompanying structural dynamics that modulate output domain activity remain to be fully elucidated. In the C-terminal light, oxygen, voltage (LOV) domain of plant phototropins (LOV2), blue light activation leads to formation of an adduct between a conserved Cys residue and the embedded FMN chromophore, rotation of a conserved Gln (Q513), and unfolding of a helix (Jα-helix) which is coupled to the output partner. In the present work, we focus on the allosteric pathways leading to Jα helix unfolding in Avena sativa LOV2 (AsLOV2) using an interdisciplinary approach involving molecular dynamics simulations extending to 7 μs, time-resolved infrared spectroscopy, solution NMR spectroscopy, and in-cell optogenetic experiments. In the dark state, t...

Fluorinated organo-silica gels doped with tetra-n-propylammonium perruthenate (TPAP) are excellent catalysts for the aerobic oxidative dehydrogenation of alcohols in supercritical CO 2 (scCO 2 ). Their activity and stability are subtly dictated by structure, depending on the degree of fluorination and on the length of the fluoroalkyl chain linked to the silica network. Such dependence reflects the hydrophilic-hydrophobic balance (HHB) of the matrix, as evaluated by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The remarkable correlation between the materials' HHB and reactivity provides a finding of general validity for reactioncontrolled mechanisms, which opens the route to the synthesis of second generation sol-gel entrapped catalysts for the production of fine chemicals in scCO 2 .

Kerosene is commonly used as solvent in industry as well as fuel for domestic purposes. It mainly consists of paraffinic, naphthenic and aromatic hydrocarbons of the range C 11 to C 14 . Some impurities like sulphur and its derivative are also associated with kerosene. Aromatic hydrocarbon particularly benzene is highly carcinogenic in nature. Similarly sulphur also creates problem of pollution, corrosion and deactivation of catalyst. Traditional method adopted in refinery for removal of aromatics and sulphur is very costly. A work is carried out to reduce concentration of aromatic hydrocarbon as well as sulphur from kerosene range hydrocarbon by using simple technique. The work shows that simple adsorption technique by using different adsorbent can able to reduce the concentration of above species to minimum level. The adopted technique is highly eco-friendly, economical and efficient. Keywords: Kerosene, sulphur in kerosene, desulphurization of kerosene, aromatic hydrocarbons, ani...

Raman probe can be used to detect substances dissolved in water. Here are reported and discussed some experimental and data treatment processes needed to identify species and also to determine their content in a mixture. A particular attention is paid to the treatment of Raman line intensity used in the calibration of the probe.

In contrast to theoretical expectations, the photolysis of 2,4,6-triazido-3-chloro-5-fluoropyridine in argon at 5 K gives rise to EPR peaks of just two triplet mononitrenes, two quintet dinitrenes, and a septet trinitrene. EPR spectral simulations in combination with DFT calculations show that observable nitrenes can be assigned to triplet 2,4-diazido-3-chloro-5-fluoropyridyl-6-nitrene ) and septet 3-chloro-5-fluoropyridyl-2,4,6-trinitrene (D S = -0.1021 cm -1 , E S = -0.0034 cm -1 ). Preferential photodissociation of the azido groups located in ortho-positions to the fluorine atom of pyridines is associated with strong π-conjugation of these groups with the pyridine ring. On photoexcitation, such azido groups are more efficiently involved in reorganization of the molecular electronic system and more easily adopt geometries of the locally excited predissociation states.

The presence of sulphur in crude oil poses enormous challenges as regards its negative environmental and economic impacts. As such, the safety of the personnel and the equipment is at high risk during the processing of Urals crude oil in Kaduna Refining and Petrochemical Company (KRPC) because of its sour nature. This study was aimed at reducing the sulphur content of the Urals crude oil prior to processing by subjecting it to oxidative desulphurization where peracetic acid was used as the oxidant in the actual mass-to-stoichiometric mass ratio ranging from 1 to 5. The oxidized sulphur compounds were thereafter extracted using acetic acid as the extraction solvent. Furthermore, atmospheric distillation was carried out on both the raw and the desulphurized crude oil samples. Finally, the sulphur contents of the various crude oil samples and their fractions were analyzed. The results showed drastic reductions in the sulphur contents up to actual mass-to-stoichiometric mass ratio of 2 but the reductions became progressively insignificant afterwards. Meanwhile, the highest reduction in the sulphur content of the crude oil was 61.6 % while those of the gasoline, kerosene, diesel and residue were 32.0, 45.1, 68.9 and 75.0 % respectively. Therefore, peracetic acid is an effective oxidant for oxidative desulphurization of the crude oil.

The synthesis, photophysical and photochemical properties of soluble 3,4-(methylendioxy)-phenoxy substituted oxo-titanium(IV) phthalocyanines (4-6) are reported for the first time. The new compounds have been characterized by elemental analysis, FT-IR, 1 H NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for fluorescence lifetimes and fluorescence, photodegradation and singlet oxygen quantum yields, of these compounds in dimethylsulfoxide (DMSO) and toluene. The effects of the position of the substituents and solvent effect on the photophysical and photochemical parameters of the oxo-titanium(IV) phthalocyanines (4-6) are also reported. The fluorescence of the substituted oxo-titanium(IV) phthalocyanine complexes (4-6) is effectively quenched by 1,4-benzoquinone (BQ) in both DMSO and toluene.

Infrared spectra of single biological cells often exhibit the 'dispersion artefact' observed as a sharp decrease in intensity on the high wavenumber side of absorption bands, in particular the Amide I band at $1655 cm À1 , causing a downward shift of the true peak position. The presence of this effect makes any biochemical interpretation of the spectra unreliable. Recent theory has shed light on the origins of the 'dispersion artefact' which has been attributed to resonant Mie scattering (RMieS). In this paper a preliminary algorithm for correcting RMieS is presented and evaluated using simulated data. Results show that the 'dispersion artefact' appears to be removed; however, the correction is not perfect. An iterative approach was subsequently implemented whereby the reference spectrum is improved after each iteration, resulting in a more accurate correction. Consequently the corrected spectra become increasingly more representative of the pure absorbance spectra. Using this correction method reliable peak positions can be obtained.

The time and expense of calibration development limit the feasibility of NIR spectroscopy for many industrial applications, with a major portion of the costs being related to creation of a sufficient set of calibration samples. Net analyte signal (NAS) and generalized least squares (GLS) pre‐processing have been proposed in the literature as methods to simplify multivariate calibration by reducing the quantity of calibration samples by orthogonalizing or shrinking interference signals. Synthetic calibration has also been reported as a method to combine interference signals with pure component spectra to generate virtual calibration models, thereby reducing the number of real calibration samples required. The goals of this paper were to (1) compare theoretical and practical differences between NAS and GLS pre‐processing and (2) explore the potential of simplified NIR calibrations, both empirical and synthetic, constructed using optical coefficient‐based signal processing on predictin...

Infrared microspectroscopic imaging data of single human prostate cancer cells, on an artificial extracellular matrix (Matrigel) thin-film surface, are presented. The spectral intensity maps, obtained in reflection mode, appear to show that the protein intensity distribution observed at the location of a cell changes dramatically depending on the concentration and/or thickness of the underlying Matrigel layer. Specifically, cells adhered to a low protein concentration or thin surface exhibit a higher protein intensity signal than the surrounding layer whereas those on a high protein concentration or thick surface exhibit a lower protein intensity signal. These results are qualitatively explained by a simple model that takes into account the fact that radiation scattered from cells can enter the collection optics of the microscope without passing through the Matrigel layer. This leads to an apparent reduction in absorption at the cell.

Fourier transform infrared spectra of a single cell in transflection geometry are seen to vary significantly with position on the cell, showing a distorted derivative-like lineshape in the region of the optically dense nucleus. A similar behaviour is observable in a model system of the protein albumin doped in a potassium bromide disk. It is demonstrated that the spectrum at any point is a weighted sum of the sample reflection and transmission and that the dominance of the reflection spectrum in optically dense regions can account for some of the spectral distortions previously attributed to dispersion artefacts. Rather than being an artefact, the reflection contribution is ever present in transflection spectra and it is further demonstrated that the reflection characteristics can be used for cellular mapping.

Infrared spectra of single biological cells often exhibit the 'dispersion artefact' observed as a sharp decrease in intensity on the high wavenumber side of absorption bands, in particular the Amide I band at $1655 cm À1 , causing a downward shift of the true peak position. The presence of this effect makes any biochemical interpretation of the spectra unreliable. Recent theory has shed light on the origins of the 'dispersion artefact' which has been attributed to resonant Mie scattering (RMieS). In this paper a preliminary algorithm for correcting RMieS is presented and evaluated using simulated data. Results show that the 'dispersion artefact' appears to be removed; however, the correction is not perfect. An iterative approach was subsequently implemented whereby the reference spectrum is improved after each iteration, resulting in a more accurate correction. Consequently the corrected spectra become increasingly more representative of the pure absorbance spectra. Using this correction method reliable peak positions can be obtained.

This paper reports on a study of the combined promoting effect of La and V oxides for ethanol formation during CO hydrogenation on silica-supported Rh catalysts. Non-promoted and La and/or V oxide promoted Rh/SiO 2 catalysts were prepared by sequential or co-impregnation methods and characterized by TEM, CO chemisorption and FT-IR. Their catalytic properties for CO hydrogenation were investigated using a differential fixed bed reactor at 230 • C and 1.8 atm. It was found that, compared to non-promoted Rh/SiO 2 , the singly promoted catalysts, Rh-La/SiO 2 and Rh-V/SiO 2 , showed improved reactivity (3×) and better ethanol selectivities. However, the doubly promoted Rh-La-V/SiO 2 catalysts exhibited even higher activity (9×) and selectivity for ethanol and other C 2+ oxygenates, with the selectivity of total C 2+ oxygenates >30% at these low pressure reaction conditions. The better performance of the Rh-La-V/SiO 2 catalysts appears to be due to a synergistic promoting effect of the combined lanthana and vanadia additions through intimate contact with Rh. Use of just more of each promoter by itself was not able to produce the enhanced catalytic performance.

The reaction of molten HDPE with MAH at 215 and 250°C using di-t-amyl peroxide and t-butyl cumyl peroxide as catalysts yielded HDPE-g-MAH accompanied by crosslinked polymer. The formation of the latter, increased by the presence of MAH and insoluble in refluxing xylene, was prevented by the presence of electron donor additives, i.e., dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and tri(nonylpheny1)phosphite (TNPP). A charge containing 0.0625-0.1258 catalyst, 5% MAH and 0.5% additive, all based on HDPE and added to the molten HDPE in four portions, resulted in gel-free polymer with an MAH content of 0.7-1.7%. HDPE-g-MAH with the least color was obtained with TNPP, followed by DMAC and DMSO. Notwithstanding the absence of gel in the HDPEg-MAH prepared from HDPE with a melt flow of 17 g/10 min, the carboxylated HDPE had a melt flow of 0.0-1 g/10 min, indicative of an increase in the molecular weight of the product. This is attributed to a coupling reaction between MAH radicals appended to the HDPE backbone (HDPE-MAH . ) and HDPE radicals formed as a result of hydrogen abstraction from HDPE by radicals from the catalyst and/or excited MAH.

In the past 136 years, numerous archaeological finds have enriched the history of Roman Apulum and Roman Province Dacia with new data. Various pieces were described and analyzed from a stylistic point of view, but they were not investigated in terms of non-invasive analytical techniques to elucidate the painting techniques and the materials used. In this context, this study aims to identify and characterize the pigments used by Roman painters/craftsmen in decorating houses using Apulum and the painting technique. To achieve this goal, fragments of Roman wall paintings recently discovered in three different archaeological excavations from the ancient Roman Apulum were selected and studied using non-invasive analytical techniques (optical microscopy and vibrational spectroscopy). They have various colors and shades, such as red, green, blue, white, yellow, and admixtures. To establish the potential materials used for wall painting, the samples were analyzed by micro-Fourier-transform infrared spectroscopy.

This paper presents the results of a laboratory study undertaken to examine the treatment of demolition waste containing calcium sulfate by means of calcium sulfoaluminate clinker (CSA). The quantity of CSA necessary to entirely consume calcium sulfate was determined. Using infrared spectrometry analysis and X-ray diffraction, it was shown that calcium sulfate was entirely consumed when the ratio between CSA and calcium sulfate was 4. Standard sand was polluted by 4% calcium sulfate. Two solutions were investigated: • either global treatment of sand by CSA, • or immobilization of calcium sulfate by CSA, followed by the introduction of this milled mixture in standard sand. Regardless of the type of treatment, swelling was almost stabilized after 28 days of immersion in water.

Spruce wood that had been degraded by brown-rot fungi (Gloeophyllum trabeum or Poria placenta) exhibiting mass losses up to 16% was investigated by transmission Fourier transform infrared (FT-IR) imaging microscopy. Here the first work on the application of FT-IR imaging microscopy and multivariate image analysis of fungal degraded wood is presented and the first report on the spatial distribution of polysaccharide degradation during incipient brown-rot of wood. Brown-rot starts to become significant in the outer cell wall regions (middle lamellae, primary cell walls, and the outer layer of the secondary cell wall S1). This pattern was detected even in a sample with non-detectable mass loss. Most significant during incipient decay was the cleavage of glycosidic bonds, i.e. depolymerisation of wood polysaccharides and the degradation of pectic substances. Accordingly, intramolecular hydrogen bonding within cellulose was reduced, while the presence of phenolic groups increased.

The NO x storage process over Ba/Al 2 O 3 and Pt-Ba/Al 2 O 3 NSR catalysts has been analyzed in this study by performing experiments at 350 °C with NO 2 and NO/O 2 mixtures using different complementary techniques (Transient Response Method, in situ FT-IR and DRIFT spectroscopies). The collected data suggest that over the Pt-Ba/Al 2 O 3 catalyst the NO x storage process from NO/O 2 mixtures occurs forming at first nitrite species, which progressively evolve to nitrates. In addition, a parallel nitrate formation via disproportionation of NO 2 (formed upon NO oxidation) cannot be excluded.

Non ordered organic-inorganic mesoporous hybrid materials with basic sites have been synthesized following a fluoride-catalysed sol-gel process, at neutral pH and low temperatures that avoids the use of structural directing agents (SDAs). Proton sponges have been used as the organic builder of the hybrids, while the inorganic part corresponds to silica tetrahedra. The proton sponges are diamines that exhibit very high basicity and, after functionalization, have been introduced as part of the walls of the mesoporous silica by one-pot synthesis. Several hybrids with different organic loadings have been synthesized and characterized by gas adsorption, thermogravimetric and elemental analysis, solid state MAS-NMR and FTIR spectroscopy. These hybrids show high activity as base catalysts and can be recycled

Non ordered organic-inorganic mesoporous hybrid materials with basic sites have been synthesized following a fluoride-catalysed sol-gel process, at neutral pH and low temperatures that avoids the use of structural directing agents (SDAs). Proton sponges have been used as the organic builder of the hybrids, while the inorganic part corresponds to silica tetrahedra. The proton sponges are diamines that exhibit very high basicity and, after functionalization, have been introduced as part of the walls of the mesoporous silica by one-pot synthesis. Several hybrids with different organic loadings have been synthesized and characterized by gas adsorption, thermogravimetric and elemental analysis, solid state MAS-NMR and FTIR spectroscopy. These hybrids show high activity as base catalysts and can be recycled

A tungsten hydride complex, [WH 2 (η 2 -OOCCH 3 )(Ph 2 PCH 2 CH 2 PPh 2 ) 2 ][BPh 4 ], was dispersed in a hybrid matrix synthesized by a solgel process. The host matrix of the so-called ureasil is a network of silica to which oligopolyoxyethylene chains [POE, (OCH 2 CH 2 ) n ] are grafted by means of urea cross-links. The free complex and sol-gel materials were characterized by thermal analysis (DSC) and spectroscopic methods (FT-IR and UV/Vis). The data gathered indicate that the tungsten(IV) complex is immobilized in the host matrix, and it exhibits structural properties different from those of the free form. These differences could arise either from distortions caused by steric effects imposed by the structure of hybrid matrix or by interactions with the matrix.

Edible canna (Canna edulis) is a potential forest product that can be used for food diversification. The objective of this study was to obtain Type IV resistant starch which has been proven beneficial because of its physiological effect. In this study, the production of resistant starch was done by chemical modification using different concentration of acetic anhydride, namely 3, 4, and 5%, in 300 g of canna. Two types of canna used in this study were red and white canna. The degree of substitution gained through acetylation was 0.082, 0.168, and 0.257 for red canna and 0.083, 0.168 and 0.256 for white canna. Through proximate analysis, modification of canna starch resulted in increase of water content and decrease of ash content, while protein content, lipid, and carbohydrate content showed no significant difference. Total starch content (amylose and amylopectin), dietary fiber, resistant starch content, and digestibility of starch were measured for native and the selected modified...