Fourier Transform Infrared Absorbance Research Articles

Effects of Artemisia dracunculus powder on dough rheology and quality properties as a novel ingredient in bread formulation.

Tarragon has a great potential to be a healthy functional food ingredient thanks to its rich antioxidant, phenolic compounds, and nutrient content. The possibility of enriching bread with tarragon was investigated. For this aim, tarragon powder was used at the rates of 0, 2, 4 and 6% instead of wheat flour. In this study, the effects of substitution on the rheological properties of bread dough and color, total phenolic content, antioxidant activity, texture, sensory, and Fourier transform infrared (FT-IR) analysis of bread samples were performed. The composition of tarragon powder showed significant protein (23.16%), crude fiber (7.4%), antioxidant (48.22 ± 0.11%), and total phenolic content (511.66 ± 1.56 mg GAE/100 g). Bread samples with increased fiber and protein content were obtained by adding tarragon powder to the bread formulation. The major differences in the FT-IR absorbance spectra for the bread samples were not observed. Additionally, tarragon powder significantly increased the antioxidative properties of breads (p < 0.05). Adding up to 4% tarragon powder to the bread formulation increased the sensory scores of the breads.

Characterization of light induced degradation in PECVD silicon nitride passivated Cz silicon wafers using spectroscopic techniques

In this work we investigate the chemical species involved in the light induced degradation of plasma enhanced chemical vapor deposited (PECVD) hydrogenated silicon nitride (SiNx:H) passivated p-type and n-type samples under normal outdoor ambient conditions. The electrical characterization measurements along with Fourier Transform Infrared (FTIR) and photoluminescence (PL) spectroscopic techniques were utilized in this study. Significant reduction in effective minority carrier lifetime values and band to band PL intensities were noticed for both p-type and n-type samples after outdoor light soaking. The apparent defect density increased from 3.39 × 10−3 µs−1 to 1.68 × 10−2 µs−1 and 3.42 × 10−4 µs−1 to 3.46 × 10−3 µs−1, respectively for p-type and n-type samples after light soaking of 111 h corresponding to cumulative solar insolation of 95.7 kWh/m2. The changes in FTIR absorbance intensities of chemical species such as SiNyHa, SiNzHb, SiHm, SiO2i and SiOn after light soaking confirmed the role of oxygen in addition to hydrogen in both p-type and n-type samples. Spectroscopic PL analysis further validated the decrease in concentration of silicon-oxygen species and reduction in effective lifetime for n-type samples. We demonstrate that the chemical species contributing to light induced bulk and surface degradation can be identified by FTIR and PL spectroscopic techniques. This work would be beneficial for understanding, modeling and mitigating the degradation mechanisms in Cz silicon wafers passivated using PECVD dielectric films.

Rapid Assessment of Quality Changes in French Fries during Deep-frying Based on FTIR Spectroscopy Combined with Artificial Neural Network.

Fourier transform infrared (FTIR) spectroscopy combined with backpropagation artificial neural network (BP-ANN) were utilized for rapid and simultaneous assessment of the lipid oxidation indices in French fries. The conventional indexes (i.e. total polar compounds, oxidized triacylglycerol polymerized products, oxidized triacylglycerol monomers, triacylglycerol hydrolysis products, and acid value), and FTIR absorbance intensity in French fries were determined during the deep-frying process, and the results showed the French fries had better quality in palm oil, followed by sunflower oil, rapeseed oil and soybean oil. The FTIR spectra of oil extracted from French fries were correlated to the reference oxidation indexes determined by AOCS standard methods. The results of BP-ANN prediction showed that the model based on FTIR fitted well (R2 > 0.926, RMSEC < 0.481) compared with partial least-squares model (R2 > 0.876). This facile strategy with excellent performance has great potential for rapid characterization quality of French fries during frying.

Identification of Salmonella Serovars before and after Ultraviolet Light Irradiation by Fourier Transform Infrared (FT-IR) Spectroscopy and Chemometrics

Vibrational properties and structural behavior upon ultraviolet (UV) irradiation are reported here for DNAs isolated from three serovars of Salmonella bacteria, respectively (S. enteritidis, S. infantis and S. typhimurium) by using Fourier transform infrared spectroscopy (FT-IR). The FT-IR absorbance spectra were recorded for bacterial DNAs, control and UV irradiated samples (30 min, 1 h, 1 h 30 min), respectively, and are presented in the wavenumber ranges from 800 to 1800 cm−1 and from 3000 to 4000 cm−1, respectively. Molecular specific structural information has been found based on DNA marker bands, which were monitored primarily in terms of intensity changes. As a general remark, a serovar’s dependent nonlinear behavior has been detected for some FT-IR band intensities corresponding to Salmonella DNAs, as a function of irradiation time. Particularly, alterations in DNA functional groups and molecular geometry have been observed. Chemometric analysis such as principal component analysis (PCA) and hierarchical clustering analysis (HCA) were successfully applied for the identification of inter- and intra- serovar differences between DNA spectra, before and after UV irradiation. The elucidation of the main spectral features characteristic to pathogenic bacterial DNAs offers further opportunity for bacteria identification and for establishing the mechanisms of infections, leading to the development of innovative diagnosis tools and more effective therapies. Particularly, DNA-damaging agents are most effective in cancer therapy.

Kinetics of the cyclization and isomerization reactions in polyacrylonitrile based carbon fiber precursors during thermal‐oxidative stabilization

ABSTRACTThe kinetics of reactions in polyacrylonitrile (PAN) based carbon fiber (CF) production should be of significance to the guidance of process control, fiber structure formation. PAN precursor fibers were isothermally stabilized at 210, 225, 240, 255, and 270 °C, respectively, for 10 to 100 min in an air oven to study the kinetics of the cyclization and isomerization reactions. The structural evolution of PAN precursor fibers during thermal‐oxidative stabilization was characterized by Fourier transform infrared (FTIR) spectroscopy and solid state 13C nuclear magnetic resonance (13C NMR). The results indicate that the FTIR absorbance of CN (the resultant of the cyclization) in PAN shows a trend of first increasing and then decreasing. And then the NMR peak assigned to the carbon atoms linking imino groups (NH) proves the isomerization of CN into NH in pyridone structure. Based upon the FTIR absorbance method, the entire process of the cyclization and isomerization reactions is considered as a consecutive first‐order reaction. A kinetic model for the consecutive reaction has been established via the evaluation of the reaction rate constants of two single reactions. According to the model, the simulated kinetic curves of the characteristic groups (CN, CN, and NH) conform to the FTIR absorbance trends of these groups based on experimental data. This study is expected to furnish in‐depth information on the crucial reaction kinetics during stabilization of PAN precursors, which is of advantage to the process optimization of the CF production. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48819.

Physical characterization of cytochrome c- and vitamin B12-doped DNA thin films

DNA can be useful in the field of biological and physical sciences due to its unique features, e.g., molecular recognition and self-assembly. Here, we fabricated cytochrome C (Cy)- and vitamin B12 (VB)-doped DNA thin films via a drop-casting method and explored their chemical and optoelectronic characteristics. Fourier transform infrared (FTIR), Raman, absorption, photoluminescence (PL), and electrical measurements were used to estimate critical concentrations of Cy and VB (where extremes of measured quantities occurred) in a fixed DNA concentration. These measurements focused on chemical interactions, binding modes, energy transfer mechanism, and electrical characteristics of the Cy- and VB-doped DNA thin films. We noticed that FTIR absorbance and Raman (UV–Vis) band intensities were increased (decreased), with an increase in the Cy concentration of up to 1.5 μM (= critical concentration of Cy) and a VB concentration of up to 3 mM (= critical concentration of VB) in DNA thin films. Significant band intensity changes and band position shifts of FTIR, Raman, and UV–Vis spectra were observed by varying concentrations of Cy and VB in DNA thin films. These changes provided the evidence of interaction between DNA and Cy (VB) via electrostatic bonding and intercalation interactions. The PL spectra exhibited strong red emissions at 612 nm. The changes of PL intensities revealed that effective energy transfer occurred between the VB and DNA up to critical concentration of VB, due to proper binding of VB. Finally, the current extremes for Cy- and VB-doped DNA thin films were observed at 1.5 μM of Cy and 3 mM of VB, respectively, which agreed well with the other characteristics.

Effects of Silanization Conditions on Flexural Properties of Sic Fiber-Reinforced Resin

Objective: The aim of this study was to evaluate the effects of silanization conditions on the mechanical properties of the SiC fiber-reinforced resin.Materials and Methods: A mixture of urethane dimethacrylate and Triethylene Glycol Dimethacrylate (TEGDMA), with camphorquinone and 2-(N,N-dimethylamino)ethyl methacrylate as the visible-light initiator, was prepared as a matrix resin. The SiC fiber containing 10 mass% oxygen was silanized by two methods, using experimental silane coupling agents containing 0.5, 1.0, and 2.0 mass% 3-(Methacryloyloxy) Propyl Trimethoxy Silane (γ-MPTS). The silanization methods were the drying method, which enabled silanization at atmospheric conditions for two weeks, and the heating method, which enabled silanization at 100°C for 30 min. After silanization, SiC fibers were analyzed by Fourier Transform Infrared (FTIR) spectroscopy. Mechanical properties of experimental SiC fiber-reinforced resin were measured by the three-point bending test according to ISO 4049:2009, and the fracture surface of SiC fiber-reinforced resin was observed using an Electron Probe Micro Analyzer (EPMA).Results: The FTIR absorbance peaks at 815 cm-1 attributed to the Si-O-CH3 groups of the γ-MPTS and 1087 cm-1 attributed to the Si-O-Si siloxane bonding were observed on the SiC fiber silanized with 1.0 mass% γ-MPTS by the drying method. Moreover, EPMA observation showed that these SiC fibers were covered with the matrix resin. Thus, these SiC fibers could adhere chemically to the matrix resin. The flexural strength and modulus of the fiberreinforced resin containing the SiC fiber silanized with 1.0 mass% γ-MPTS using the drying method were 238.7 ± 41.1 MPa and 6.0 ± 1.1 GPa, respectively. In contrast, those of the SiC fiber-reinforced resin containing the SiC fibers silanized by the heating method was not improved.Conclusion: The reinforced resin containing the SiC fiber silanized with 1.0 mass% γ-MPTS by the drying method showed mechanical properties superior to those of the other SiC fiber-reinforced resin.

A study of the thermal degradation of six typical municipal waste components in CO2 and N2 atmospheres using TGA-FTIR

Thermal degradation of six typical municipal solid waste (MSW) components (tire rubber (TR), recycled polyvinyl chloride pellets (PVC), wood sawdust (WS), paper mixture (PM), kitchen waste (KW) and textile (TE)) in CO2 and N2 atmospheres is studied by using a thermogravimetric analyzer (TGA) combined with Fourier transform infrared (FTIR) spectrometer. Below 600°C, CO2 behaves as an inert atmosphere and samples display similar weight loss behavior in both atmospheres. In this temperature range, the gas species and variations of FTIR absorbance depend on the waste composition rather than atmosphere type. Most of gases display identical evolution trends in both N2 and CO2, and the experience for pyrolysis in N2 can also be used for pyrolysis in CO2, and simply replacement of N2 by CO2 can’t improve the pyrolysis performance. Above 600°C, atmosphere changes not only the location of the DTG peak but also its formation mechanism, and CO2 behaves as a reaction atmosphere. In the later thermal degradation, the growth rate of CO absorbance in CO2 is significantly faster than in N2, indicating waste pyrolysis in CO2 can increased the syngas production at higher temperatures.

Spectroscopic Investigation for Purity Evaluation of Detonation Nanodiamonds: Experimental Approach in Absorbance and Scattering

Nanodiamond powders have excellent mechanical, chemical, physical, and optical properties. In this research, two non-pure groups of nanodiamond particles labeled as ND1 and ND2 have been selected for purity evaluation by means of absorbance and scattering analysis. The nanodiamond powders have been used for Raman and dynamic light scattering (DLS), Fourier transform infrared (FTIR) and UV–Vis absorbance approaches. The Raman spectra show a weak diamond signal in ND2 as purity and 4 basic set of bands. FTIR absorbance spectroscopy was used in the spectral range of 400–3600 cm−1. The results show that ND2 is almost non-absorbance with wavelength. It means that the diamond phase purity of ND2 is greater than ND1, and ND2 shows a better structure of diamond. UV–Vis absorption spectra of the sample have been recorded in the spectral range of 200–800 nm by means of nanodiamond suspended in methanol (NDM). The UV–Vis absorbance of NDM1 is stronger than NDM2 at the same concentration. Therefore the diamond phase purity of ND2 is greater than ND1. Particle size distribution and zeta potential of DNDs were investigated by DLS method. Finally the structure and phase of samples have been evaluated by X-ray diffraction (XRD) for confirmation.

Differentiating Styles of Alteration within Kaolin-Alunite Hydrothermal Deposits of Çanakkale, NW Turkey

AbstractThe Biga Peninsula of NW Turkey is host to many kaolin and halloysite deposits with mineralization occurring at the intersections of fault zones in contact with Late Eocene-Miocene calc-alkaline volcanic rocks. Distinguishing between the relative overprinting of hypogene by supergene processes in these deposits is a challenge and important because they affect the physical-chemical properties of minerals and their potential for industrial applications. This study examines the Sarıbeyli-Sığırlı and Bodurlar kaolin deposits in NW Turkey, which were formed from similar volcanics as evidenced by 40Ar/39Ar. Late Eocene (34.2 ± 0.20 Ma) to Early Oligocene (32.7 ± 0.17 Ma) ages for both primary volcanic rocks and alunites are consistent with surrounding rocks in the Çanakkale region. Criteria used to distinguish hypogene alteration from supergene alteration processes come from X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and Raman spectroscopies, thermal gravimetric analysis (TGA), scanning and transmission electron microscopy (SEM, TEM), and elemental analyses. Isotopic δ18O depletion and δD enrichment of the Sarıbeyli-Sığırlı deposit suggests that it was more influenced by magmatic waters than was the Bodurlar deposit. The Bodurlar deposit contains a paucity of dickite compared to the Sarıbeyli-Sığırlı deposit, which is evidenced by lower TGA endotherms, higher ratios of XRD intensities for reflections at 1.316 Å and 1.307 Å, distinctive FTIR absorbance bands at 3620 cm− 1 and 3652 cm−1, and relative Raman intensities of the γ1 and γ5 vibrational modes.A genetic model is proposed whereby these deposits are mainly formed through an acid-sulfate hydrothermal alteration, in what appears to be a volcanic-hydrothermal system. The extent of hydrothermal alteration was controlled by fault density and the initial texture of the volcanic rocks. These steam-heated environments included sulfide-enriched vapors and groundwater mixed to varying degrees in the vadose zone. The Sarıbeyli-Sığrlı and Bodurlar deposits, respectively, contain mineral assemblages that reflect both hypogene (kaolinite, alunite, dickite) and supergene (kaolinite, halloysite, jarosite) processes. These observations offer a basis for comparing and discriminating the relative influence of these two important alteration processes responsible for the formation of kaolin deposits in NW Turkey and around the world.

Predicting ambient aerosol thermal–optical reflectance (TOR) measurements from infrared spectra: extending the predictions to different years and different sites

Abstract. Organic carbon (OC) and elemental carbon (EC) are major components of atmospheric particulate matter (PM), which has been associated with increased morbidity and mortality, climate change, and reduced visibility. Typically OC and EC concentrations are measured using thermal–optical methods such as thermal–optical reflectance (TOR) from samples collected on quartz filters. In this work, we estimate TOR OC and EC using Fourier transform infrared (FT-IR) absorbance spectra from polytetrafluoroethylene (PTFE Teflon) filters using partial least square regression (PLSR) calibrated to TOR OC and EC measurements for a wide range of samples. The proposed method can be integrated with analysis of routinely collected PTFE filter samples that, in addition to OC and EC concentrations, can concurrently provide information regarding the functional group composition of the organic aerosol. We have used the FT-IR absorbance spectra and TOR OC and EC concentrations collected in the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network (USA). We used 526 samples collected in 2011 at seven sites to calibrate the models, and more than 2000 samples collected in 2013 at 17 sites to test the models. Samples from six sites are present both in the calibration and test sets. The calibrations produce accurate predictions both for samples collected at the same six sites present in the calibration set (R2 = 0.97 and R2 = 0.95 for OC and EC respectively), and for samples from 9 of the 11 sites not included in the calibration set (R2 = 0.96 and R2 = 0.91 for OC and EC respectively). Samples collected at the other two sites require a different calibration model to achieve accurate predictions. We also propose a method to anticipate the prediction error; we calculate the squared Mahalanobis distance in the feature space (scores determined by PLSR) between new spectra and spectra in the calibration set. The squared Mahalanobis distance provides a crude method for assessing the magnitude of mean error when applying a calibration model to a new set of samples.

Predicting ambient aerosol thermal–optical reflectance measurements from infrared spectra: elemental carbon

Abstract. Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as thermal–optical reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier transform infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive and nondestructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FT-IR spectra are divided into calibration and test sets. Two calibrations are developed: one developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a uniform distribution of Low EC mass samples (EC &lt; 2.4 μg, Low Uniform EC). A hybrid approach which applies the Low EC calibration to Low EC samples and the Uniform EC calibration to all other samples is used to produce predictions for Low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), no bias (0.00 μg m−3, a concentration value based on the nominal IMPROVE sample volume of 32.8 m3), low error (0.03 μg m−3) and reasonable normalized error (21 %). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision and accuracy to collocated TOR measurements. Only the normalized error is higher for the FT-IR EC measurements than for collocated TOR. FT-IR spectra are also divided into calibration and test sets by the ratios OC/EC and ammonium/EC to determine the impact of OC and ammonium on EC prediction. We conclude that FT-IR analysis with partial least squares regression is a robust method for accurately predicting TOR EC in IMPROVE network samples, providing complementary information to TOR OC predictions (Dillner and Takahama, 2015) and the organic functional group composition and organic matter estimated previously from the same set of sample spectra (Ruthenburg et al., 2014).

Time-resolved FT-IR microspectroscopy of protein aggregation induced by heat-shock in live cells.

Maintaining the correct folding of cellular proteins is essential for preserving cellular homeostasis. Protein dishomeostasis, aberrant protein folding, and protein aggregation are indeed involved in several diseases including cancer, aging-associated, and neurodegenerative disorders. Accumulation of protein aggregates can also be induced from a variety of stressful conditions, such as temperature increase or oxidative stress. In this work, we monitored by Fourier transform-infrared (FT-IR) microspectroscopy the response of live breast cancer MCF-7 and mammary breast adenocarcinoma MDA-MB 231 cell lines to severe heat-shock (HS), caused by the rise of the cellular medium temperature from 37 ± 0.5 °C to 42 ± 0.5 °C. Through the study of the time-evolution of the second derivatives of the spectra and by the 2D correlation analysis of FT-IR absorbance data, we were able to identify a common sudden heat-shock response (HSR) among the two cell lines. The hyperfluidization of mammalian cell membranes, the transient increment of the signal lipids, as well as the alteration of proteome profile were all monitored within the first 40 min of stress application, while the persistent intracellular accumulation of extended β-folded protein aggregates was detected after 40 min up to 2 h. As a whole, this paper offers a further prove of the diagnostic capabilities of FT-IR microspectroscopy for monitoring in real-time the biochemical rearrangements undergone by live cells upon external stimulation.

Predicting ambient aerosol thermal-optical reflectance (TOR) measurements from infrared spectra: organic carbon

Abstract. Organic carbon (OC) can constitute 50% or more of the mass of atmospheric particulate matter. Typically, organic carbon is measured from a quartz fiber filter that has been exposed to a volume of ambient air and analyzed using thermal methods such as thermal-optical reflectance (TOR). Here, methods are presented that show the feasibility of using Fourier transform infrared (FT-IR) absorbance spectra from polytetrafluoroethylene (PTFE or Teflon) filters to accurately predict TOR OC. This work marks an initial step in proposing a method that can reduce the operating costs of large air quality monitoring networks with an inexpensive, non-destructive analysis technique using routinely collected PTFE filter samples which, in addition to OC concentrations, can concurrently provide information regarding the composition of organic aerosol. This feasibility study suggests that the minimum detection limit and errors (or uncertainty) of FT-IR predictions are on par with TOR OC such that evaluation of long-term trends and epidemiological studies would not be significantly impacted. To develop and test the method, FT-IR absorbance spectra are obtained from 794 samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least-squares regression is used to calibrate sample FT-IR absorbance spectra to TOR OC. The FTIR spectra are divided into calibration and test sets by sampling site and date. The calibration produces precise and accurate TOR OC predictions of the test set samples by FT-IR as indicated by high coefficient of variation (R2; 0.96), low bias (0.02 μg m−3, the nominal IMPROVE sample volume is 32.8 m3), low error (0.08 μg m−3) and low normalized error (11%). These performance metrics can be achieved with various degrees of spectral pretreatment (e.g., including or excluding substrate contributions to the absorbances) and are comparable in precision to collocated TOR measurements. FT-IR spectra are also divided into calibration and test sets by OC mass and by OM / OC ratio, which reflects the organic composition of the particulate matter and is obtained from organic functional group composition; these divisions also leads to precise and accurate OC predictions. Low OC concentrations have higher bias and normalized error due to TOR analytical errors and artifact-correction errors, not due to the range of OC mass of the samples in the calibration set. However, samples with low OC mass can be used to predict samples with high OC mass, indicating that the calibration is linear. Using samples in the calibration set that have different OM / OC or ammonium / OC distributions than the test set leads to only a modest increase in bias and normalized error in the predicted samples. We conclude that FT-IR analysis with partial least-squares regression is a robust method for accurately predicting TOR OC in IMPROVE network samples – providing complementary information to the organic functional group composition and organic aerosol mass estimated previously from the same set of sample spectra (Ruthenburg et al., 2014).

Waterless TiO2 atomic layer deposition using titanium tetrachloride and titanium tetraisopropoxide

The surface chemistry for TiO2 atomic layer deposition (ALD) typically utilizes water or other oxidants that can oxidize underlying substrates such as magnetic disks or semiconductors. To avoid this oxidation, waterless or oxidant-free surface chemistry can be used that involves titanium halides and titanium alkoxides. In this study, waterless TiO2 ALD was accomplished using titanium tetrachloride (TiCl4) and titanium tetraisopropoxide (TTIP). In situ transmission Fourier transform infrared (FTIR) studies were employed to study the surface species and the reactions during waterless TiO2 ALD. At low temperatures between 125 and 225 °C, the FTIR absorbance spectra revealed that the isopropoxide species remained on the surface after TTIP exposures. The TiCl4 exposures then removed the isopropoxide species and deposited additional titanium species. At high temperatures between 250 and 300 °C, the isopropoxide species were converted to hydroxyl species by β-hydride elimination. The observation of propene gaseous reaction product by quadrupole mass spectrometry (QMS) confirmed the β-hydride elimination reaction pathway. The TiCl4 exposures then easily reacted with the hydroxyl species. QMS studies also observed the 2-chloropropane and HCl gaseous reaction products and monitored the self-limiting nature of the TTIP reaction. Additional studies examined the waterless TiO2 ALD growth at low and high temperature. Quartz crystal microbalance measurements observed growth rates of ∼3 ng/cm2 at a low temperature of 150 °C. Much higher growth rates of ∼15 ng/cm2 were measured at a higher temperature of 250 °C under similar reaction conditions. X-ray reflectivity analysis measured a growth rate of 0.55 ± 0.05 Å/cycle at 250 °C. X-ray photoelectron depth-profile studies showed that the TiO2 films contained low Cl concentrations &amp;lt;1 at. %. This waterless TiO2 ALD process using TiCl4 and TTIP should be valuable to prevent substrate oxidation during TiO2 ALD on oxygen-sensitive substrates.

Pyrolysis of Huang Tu Miao coal over faujasite zeolite and supported transition metal catalysts

Abstract Catalyst surface modification with supported metals is an efficient way of controlling coal pyrolysis and enhancing the production of high value-added chemicals. In this work, zeolite NaX and CoO x -, MoO x -, and CoO x –MoO x -supported NaX catalysts were prepared and characterized by transmission electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, X-ray diffraction, and Brunauer–Emmett–Teller analysis. Huang Tu Miao (HTM) coal, a typical long flame coal in Western China, was selected as the testing material. The pyrolysis of HTM coal was conducted in 5% H 2 /N 2 atmosphere, and the volatiles were examined by thermogravimetric (TG) Fourier-transform infrared (FTIR) spectroscopy. The addition of zeolite NaX significantly enhanced the production of CO, CH 4 , and aromatic and aliphatic hydrocarbons, and dramatically reduced the generation of CO 2 . These results are in contrast to the transition metal oxide-supported HZSM-5 in our previous report. In addition, the pyrolysis product profiles, expressed by FTIR absorbance, were similar for the HTM-NaX and HTM-HZSM-5 mixtures but different for the HTM-transition-metal-incorporated zeolite NaX and HZSM-5 mixtures. This result may imply differences in pyrolysis mechanism. Catalyst composition, pore size, and acidity may play key roles in pyrolysis. The pyrolysis kinetics of HTM coal was determined by the single reaction, first-order model. The lowest activation energy of the secondary degasification stage was observed in CoO x –MoO x /NaX.

Effects of scalp dermatitis on chemical property of hair keratin

The effects of scalp dermatitis (seborrheic dermatitis (SD), psoriasis, and atopic dermatitis (AD)) on chemical properties of hair keratin were investigated by Fourier transform infrared (FT-IR) spectroscopy. Hairs were collected from lesional regions affected by SD, psoriasis, and AD and non-lesional regions separately. The hairs with SD were taken from patients with ages of 16–80years. The ages of patients with psoriasis ranged from 8 to 67years, and all patients exhibited moderate disease. Hairs with AD were taken from the patients with ages of 24–45years and the average SCORing atopic dermatitis (SCORAD) was 48.75. Hairs from 20 normal adults were collected as a control. The FT-IR absorbance bands were analyzed by the Gaussian model to obtain the center frequency, half width, height, and area of each band. The height and area of all bands in the spectra were normalized to the amide I centered at 1652cm−1 to quantitatively analyze the chemical composition of keratin. The spectra of hair with scalp dermatitis were different with that of control, the amide A components centered at 3278cm−1 were smaller than those of the control. The psoriasis hair showed a large difference in the IR absorbance band between lesional and non-lesional hairs indicating good agreement with the morphological changes. The hairs with diseases did not show differences in the content of cystine, which was centered at 1054cm−1, from the control. The chemical properties of keratin were not significantly different between the hairs affected by SD, psoriasis, and AD. However, the changes induced by scalp dermatitis were different with weathering. Therefore, FT-IR analysis could be used to screen differences between the physiological and pathological conditions of scalp hair.

Analysis of aging effects on chemical property of human hair by Fourier transform infrared spectroscopy

In the previous work, we investigated the aging effect on morphology and mechanical property of the hair by using atomic force microscopy. The effects of aging on chemical properties of human hair were investigated by Fourier transform infrared (FT-IR) spectroscopy. Healthy hair samples with no diseases were collected from 60 Koreans (30 males and 30 females) and they were grouped by age: 1-10, 11-20, 21-30, 31-40, 41-50, and 51-60 years. The characteristic parameters of FT-IR absorbance bands including center frequency, half width, height, and area were analyzed using the Gaussian model. To quantitatively analyze the chemical composition of hair, the height and area of all bands in the spectra were normalized to the amide I centered at 1652-1659 and 1654-1658 cm(-1), for male and female hairs, respectively. In all male and female hairs, the spectra of specific components of the hair keratin showed to have the same dependence on aging. The center positions of the bands arising from amide A, CH(3) mode, and amide I were altered by aging. The female hair contains more cystein than the male hair. Changes in the amount of amide II and amide A by aging were more significant in male hair than in female hair. The changes in chemical components of the hair according to the ages were shown at the inflection point at 30 s.

FTIR spectra of algal species can be used as physiological fingerprints to assess their actual growth potential

Fourier transform infrared (FTIR) spectra were measured from cells of Microcystis aeruginosa and Protoceratium reticulatum, whose growth rates were manipulated by the availability of nutrients or light. As expected, the macromolecular composition changed in response to the treatments. These changes were species-specific and depended on the type of perturbation applied to the growth regime. Microcystis aeruginosa showed an increase in the carbohydrate-to-protein ratio with decreased growth rates, under nutrient limitation, whereas light limitation induced a decrease of the carbohydrate-to-protein ratio with decreasing proliferation rates. The macromolecular pools of P. reticulatum showed a higher degree of compositional homeostasis. Only when the lowest light irradiance and nutrient availability were supplied, an increase of the carbohydrate-to-protein FTIR absorbance ratio was observed. A species-specific partial least squares (PLS) model was developed using the whole FTIR spectra. This model afforded a very high correlation between the predicted and the measured growth rates, regardless of the growth conditions. On the contrary, the prediction based on absorption band ratios generally used in FTIR studies would strongly depend on growth conditions. This new computational method could constitute a substantial improvement in the early warning systems of algal blooms and, in general, for the study of algal growth, e.g. in biotechnology. Furthermore, these results confirm the suitability of FTIR spectroscopy as a tool to map complex biological processes like growth under different environmental conditions.

Study of Late Roman and Byzantine glass by the combined use of analytical techniques

In the present work, we report on a detailed characterization of Late Roman and Byzantine (from 2nd to 8th century A.D.) glass specimen found in Catania (Sicily, Southern Italy) by the employment of two complementary techniques, namely scanning electron microscopy coupled with energy-dispersive spectrometry (SEM–EDS) and Fourier transform infrared (FT-IR) absorbance spectroscopy. The glass fragments come from archaeological excavations in the courtyard of St. Agata la Vetere's church in Catania. In particular, compositional data were obtained by scanning SEM–EDS measurements and the investigation of the degradation on the surface of the glass specimen was made combining the SEM–EDS observations with those performed through FT-IR absorbance. The whole set of results contributed to define the provenance of the specimens. Furthermore, the data furnished new evidences of the technical development of glass production in Late Roman and Byzantine period in Catania.