Near Infrared Spectroscopy and Chemometrics Studies of Temperature-Dependent Spectral Variations of Water: Relationship between Spectral Changes and Hydrogen Bonds

1995 ◽  
Vol 3 (4) ◽  
pp. 191-201 ◽  
Author(s):  
Hisashi Maeda ◽  
Yukihiro Ozaki ◽  
Munehiro Tanaka ◽  
Nobuyuki Hayashi ◽  
Takayuki Kojima
Keyword(s):  
Hydrogen Bonds ◽  
Curve Fitting ◽  
Near Infrared ◽  
Difference Spectrum ◽  
Second Derivative ◽  
Pls Regression ◽  
Temperature Dependent ◽  
Multilinear Regression ◽  
Spectral Changes ◽  
The Difference

The present study aims to provide new insights into the temperature-dependent spectral variations in the near infrared (NIR) region of the spectrum of water by comparing chemometrics with spectroscopic analysis. Fourier transform (FT)-NIR spectra of water in the 9000–5500 cm−1 region have been measured over a temperature range of 5–85°C. The observed spectral changes have been analysed by both chemometrics, such as multilinear regression (MLR), principal component regression (PCR) and partial least squares (PLS) regression, and spectroscopic data analyses, such as second derivative, difference spectra and curve fitting. The second derivative of the NIR spectra of water suggests that an intense feature around 6900 cm−1, due to the combination of antisymmetric and symmetric stretching modes of water, consists of at least five component spectra. Each component spectrum may be ascribed to the water species with no, one, two, three and four hydrogen bonds. Curve fitting has been performed for the 6900 cm−1 band and it has been found that the species with no hydrogen bonds increase largely with temperature, while those with more than two hydrogen bonds decrease. The temperature of water has been predicted by use of MLR, PCR and PLS regression. PCR and PLS regression loadings plots for Factor 1 of the models for the prediction of the temperature of water are almost identical with the difference spectrum of water between 5 and 85°C; both the loadings plots and the difference spectrum reflect strongly the changes in the hydrogen bonds of water. Loadings plots of Factor 1 of the PCR and PLS regression models are very similar to each other. It is very likely that since the temperature-dependent spectral variations of water in the NIR region are very regular, and the spectra have only very small noise and baseline changes, PCR and PLS regression select nearly identical factors.

The interaction of bovine milk caseins with the detergent sodium dodecyl sulphate. II. The effect of detergent binding on spectral properties of caseins

1970 ◽  
Vol 37 (2) ◽  
pp. 259-267 ◽  
Author(s):  
G. C. Cheeseman ◽  
Dorothy J. Knight
Keyword(s):  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Bovine Milk ◽  
Difference Spectrum ◽  
Temperature Dependent ◽  
Difference Spectra ◽  
Negative Change ◽  
Tryptophan Residues ◽  
Hydrophobic Binding ◽  
The Difference

SummaryThe dissociation of casein aggregates by the detergent sodium dodecyl sulphate (SDS) gave rise to difference spectra and these spectra were characteristic for each of the different types of casein. Increase in absorption by the chromophore groups, tyrosine and tryptophan, when αs1- and β-casein aggregates were dissociated indicated binding of the detergent at regions of the molecule containing these residues. A decrease in absorption when κ-casein was dissociated indicated that the tyrosine and tryptophan residues were not in the region of the molecule to which the detergent was bound and that in the κ-casein aggregate these residues were in a more hydrophobic environment. Peaks on the difference spectra were obtained at 280 and 288 nm for αs1-casein and 284 and 291 nm for β-casein and troughs at 278 and 286 nm for κ-casein. The difference spectrum reached a maximum value when the αsl- and β-casein aggregates were dissociated and the further binding of SDS did not alter this value. The large negative change in the difference spectrum of κ-casein did not occur until after most of the aggregates were dissociated and did not reach a maximum until binding with SDS was complete. The value obtained for ΔOD was found to be temperature-dependent for β-casein-SDS interaction, but not for αs1- and κ-casein. Changes in spectra were also observed when αs1- and κ-casein interacted to form aggregates. The data obtained confirmed the importance of hydrophobic binding in casein aggregate formation and indicated the possible involvement of tyrosine and tryptophan residues in this binding.

Understanding the function of water during the gelation of globular proteins by temperature-dependent near infrared spectroscopy

2018 ◽  
Vol 20 (30) ◽  
pp. 20132-20140 ◽  
Author(s):  
Li Ma ◽  
Xiaoyu Cui ◽  
Wensheng Cai ◽  
Xueguang Shao
Keyword(s):  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Globular Proteins ◽  
Temperature Dependent

Water with two hydrogen bonds plays an important role in the gelation of globular proteins.

Rapid and nondestructive evaluation of hygroscopic behavior changes of thermally modified softwood and hardwood samples using near-infrared hyperspectral imaging (NIR-HSI)

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Te Ma ◽  
Laurence Schimleck ◽  
Tetsuya Inagaki ◽  
Satoru Tsuchikawa
Keyword(s):  
Hyperspectral Imaging ◽  
Curve Fitting ◽  
Near Infrared ◽  
Bound Water ◽  
Japanese Cedar ◽  
European Beech ◽  
Imaging Method ◽  
Nmr Studies ◽  
The Difference ◽  
Hygroscopic Behavior

AbstractThe objective of this work was to provide a rapid and nondestructive imaging method for evaluating the hygroscopic behavior of thermally modified lignocellulosic materials (softwood and hardwood). The difference in the hygroscopic behavior was explained by moisture content (MC) mapping results and molecular association characteristics of absorbed water (i.e. weakly, moderately, and strongly hydrogen-bonded water molecules) with wood at various relative humidities (RH). To achieve this goal, near-infrared (NIR) spectral images in the wavelength range 1816–2130 nm (covering the combination of stretching and deformation vibrations for OH) were used to visualize MC distributions over the surface of Japanese cedar and European beech samples which had been thermally treated at different temperatures. A curve fitting method was utilized to explore changes in water-wood structure characteristics based on shifts to longer wavelength in spectral signals caused by increasing MC. The curve fitting results support the recent nuclear magnetic resonance (NMR) studies that different bound water stabilities may pool in different compartments of the wood cell wall. Furthermore, water was firmly bound to wood at low RHs and H-bonds gained mobility as the number of absorbed molecules increased. It is concluded that NIR hyperspectral imaging also has the potential to be a complementary methodology for studying the transient changes of wood-water interactions before equilibrium.

Understanding the role of water in the aggregation of poly(N,N-dimethylaminoethyl methacrylate) in aqueous solution using temperature-dependent near-infrared spectroscopy

2019 ◽  
Vol 21 (10) ◽  
pp. 5780-5789 ◽  
Author(s):  
Li Wang ◽  
Xuewei Zhu ◽  
Wensheng Cai ◽  
Xueguang Shao
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Temperature Dependent ◽  
Dimethylaminoethyl Methacrylate

Water with two hydrogen bonds plays an important role in the phase transition of LCST polymers.

Analysis of Light-Induced Absorbance Changes in the Near-Infrared Spectral Region I. Characterization of Various Components in Isolated Chloroplasts

1991 ◽  
Vol 46 (3-4) ◽  
pp. 233-244 ◽  
Author(s):  
Christof Klughammer ◽  
Ulrich Schreiber
Keyword(s):  
Spectral Region ◽  
Near Infrared ◽  
Difference Spectrum ◽  
Light Sources ◽  
Redox Titration ◽  
Light Emitting ◽  
Infrared Spectral ◽  
Absorbance Changes ◽  
The Difference ◽  
Induced Signal

Light-induced absorbance changes in the near-infrared (NIR ) spectral region (700-950 nm) are analyzed in isolated spinach chloroplasts using pulsed light-emitting diodes as modulated measuring light sources. With chloroplasts under coupled conditions the light-induced signal is dominated by a relatively slow scattering change displaying a flat difference spectrum. More specific changes can be distinguished by faster induction and relaxation kinetics and in the presence of valinomycin/nigericin which prevents scattering changes. Besides the dominant P700 change, with a narrow bleaching band around 703 nm and a broad absorbance increase between 750 and 850 nm (peak at 815 nm) the following absorbance changes were identified in the NIR: 1) An absorbance increase caused by plastocyanin (PC) oxidation, with a relatively flat spectrum. 2) An absorbance decrease gaining amplitude towards longer wavelengths, which reflects reduction of a low potential acceptor of PSI different from ferredoxin. 3) A field indicating absorbance decrease peaking around 730 nm, the properties of which correspond to those of P515. 4) An uncoupler insensitive absorbance decrease stimulated by dark adaptation and anaerobic conditions, the difference spectrum of which resembles that of ferredoxin reduction. The relative contributions of P700 and PC to the overall oxidized-reduced difference spectrum are determined by redox titration. At 706 nm, 815 nm and 950 nm the P 700/PC is - 119/ 19, 67/37 and 31/69, respectively. From these ratios and the molar extinction coefficients a molar P 700/PC stoichiometry of 1 /3 is determined.

scholarly journals Effects of anions on a monomeric and a dimeric arginine kinase

1975 ◽  
Vol 149 (2) ◽  
pp. 387-395 ◽  
Author(s):  
E O Anosike ◽  
D C Watts
Keyword(s):  
Creatine Kinase ◽  
Mixed Type ◽  
Arginine Kinase ◽  
Difference Spectrum ◽  
Ionization State ◽  
Temperature Dependent ◽  
Tyrosine Residues ◽  
Dead End ◽  
Low Concentrations ◽  
The Difference

1. Some effects of anions on the rates of phosphoarginine synthesis by monomeric (lobster) and by dimeric (Holothuria forskali) arginine kinases are reported. 2. As with creatine kinase, acetate ions activate both enzymes: Cl- was also found to activate both although this was an inhibitor of creatine kinase. 3. NO3- inhibits the lobster enzyme. Inhibition is of the mixed type with respect to MgATP. Ki > Ki' and Ks > Ks' indicating that the presence of NO3- promotes the binding of substrate and vice versa. 4. NO3- alone has no effect on the difference spectrum of the lobster enzyme but in the presence of arginine, MgATP, MgADP, MgAMP or MgIDP the difference spectrum is greatly enhanced. A profound effect on the ionization state of tyrosine residues is inferred. 5. With the Holothuria enzyme low concentrations of NO3- activate in a manner that is competitive with arginine. Higher concentrations cause inhibition of the mixed type with respect to arginine in a similar manner to that found with MgATP for the lobster kinase. 6. Of a range of anions tested only NO3- and NO2- enhanced the inhibition of enzyme activity by MgADP, indicating the formation of a pseudo-transition-state dead-end complex, enzyme-arginine-NO3--MgADP. The effect was essentially independent of temperature with the Holothuria enzyme, but with the lobster enzyme was much less marked and temperature dependent. The difference may reflect the different stabilities of the monomer and dimer enzymes, although with neither arginine kinase is the stabilization of the dead-end complex as marked as is found with creatinine kinase.

Temperature-Dependent Logic Failure in a GaAs Power Amplifier-Duplexer Module Caused by a Subtle Parasitic Schottky Diode

2014 ◽  
Author(s):  
Rose Emergo ◽  
Steve Brockett ◽  
Pat Hamilton
Keyword(s):  
Power Amplifier ◽  
Schottky Diode ◽  
Production Test ◽  
Temperature Dependent ◽  
Cold Temperatures ◽  
Collector Junction ◽  
Power Mode ◽  
The Difference ◽  
Base Contact ◽  
Single Power

Abstract A single power amplifier-duplexer device was submitted by a customer for analysis. The device was initially considered passing when tested against the production test. However, further electrical testing suggested that the device was stuck in a single power mode for a particular frequency band at cold temperatures only. This paper outlines the systematic isolation of a parasitic Schottky diode formed by a base contactcollector punch through process defect that pulled down the input of a NOR gate leading to the incorrect logic state. Note that this parasitic Schottky diode is parallel to the basecollector junction. It was observed that the logic failure only manifested at colder temperatures because the base contact only slightly diffused into the collector layer. Since the difference in the turn-on voltages between the base-collector junction and the parasitic Schottky diode increases with decreasing temperature, the effect of the parasitic diode is only noticeable at lower temperatures.

scholarly journals Action and Entropy in Heat Engines: An Action Revision of the Carnot Cycle

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 860
Author(s):  
Ivan R. Kennedy ◽  
Migdat Hodzic
Keyword(s):  
Heat Engine ◽  
Working Fluid ◽  
Field Energy ◽  
Carnot Cycle ◽  
Gibbs Potential ◽  
Atmospheric Gases ◽  
Temperature Dependent ◽  
Expansion Phase ◽  
Heat Engines ◽  
The Difference

Despite the remarkable success of Carnot’s heat engine cycle in founding the discipline of thermodynamics two centuries ago, false viewpoints of his use of the caloric theory in the cycle linger, limiting his legacy. An action revision of the Carnot cycle can correct this, showing that the heat flow powering external mechanical work is compensated internally with configurational changes in the thermodynamic or Gibbs potential of the working fluid, differing in each stage of the cycle quantified by Carnot as caloric. Action (@) is a property of state having the same physical dimensions as angular momentum (mrv = mr2ω). However, this property is scalar rather than vectorial, including a dimensionless phase angle (@ = mr2ωδφ). We have recently confirmed with atmospheric gases that their entropy is a logarithmic function of the relative vibrational, rotational, and translational action ratios with Planck’s quantum of action ħ. The Carnot principle shows that the maximum rate of work (puissance motrice) possible from the reversible cycle is controlled by the difference in temperature of the hot source and the cold sink: the colder the better. This temperature difference between the source and the sink also controls the isothermal variations of the Gibbs potential of the working fluid, which Carnot identified as reversible temperature-dependent but unequal caloric exchanges. Importantly, the engine’s inertia ensures that heat from work performed adiabatically in the expansion phase is all restored to the working fluid during the adiabatic recompression, less the net work performed. This allows both the energy and the thermodynamic potential to return to the same values at the beginning of each cycle, which is a point strongly emphasized by Carnot. Our action revision equates Carnot’s calorique, or the non-sensible heat later described by Clausius as ‘work-heat’, exclusively to negative Gibbs energy (−G) or quantum field energy. This action field complements the sensible energy or vis-viva heat as molecular kinetic motion, and its recognition should have significance for designing more efficient heat engines or better understanding of the heat engine powering the Earth’s climates.

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