Film-forming amines (FFAs) are promising corrosion inhibitors for power plant water-steam cycles, but their mechanisms of corrosion inhibition had remained unclear. This review presents a series of studies elucidating the film structure and hydrothermal reaction mechanisms of FFAs using analytical chemistry approaches. For film structure analysis, multiple complementary techniques with different principles and spatial scales were integrated: quantitative NMR spectroscopy, microscopic reflection-absorption IR spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and inductively coupled plasma atomic emission spectrometry. Crossvalidation through independent agreement of film thickness and adsorption data from each method demonstrated a multilayer structure with an average thickness of 0.5 mu m (corresponding to several hundred layers). For hydrothermal reaction analysis, NMR measurements using high-pressure-resistant quartz cells combined with multinuclear NMR and isotope labeling enabled identification of decomposition products and elucidation of reaction pathways. These studies provide a scientific foundation for practical application of FFAs and demonstrate the role of analytical chemistry in deepening scientific understanding of complex practical systems through a multi-faceted analytical approach.

Poly(N-acryloylglycine methyl ester) [poly(NAcGlyMe)], bearing both amide and ester carbonyl groups in each side chain, was designed to enhance the hydrogen bonding between adjacent side chains, leading to an anomalous hysteresis phenomenon. An atactic polymer was prepared, as a reference for stereoregularity effects, via photo-iniferter reversible addition-fragmentation chain transfer polymerization in methanol at 60 degrees C. The lower critical solution temperature (LCST)-type phase transition behavior of its aqueous solution was investigated by monitoring the transmittance at 500 nm. Contrary to conventional LCST behavior, the polymer exhibited a remarkably rare phase transition, namely inverse hysteresis, in which the phase transition temperature during cooling (80.2 degrees C) was higher than that during heating (77.8 degrees C). Moreover, the transition temperature increased irreversibly upon repeated heating-cooling cycles, and by the fifth cycle, no distinct decrease in transmittance was observed. Notably, an amide proton signal was detected in the 1H nuclear magnetic resonance (NMR) spectrum of the polymer recovered after the sixth heating-cooling cycle, although it is typically undetectable in D2O due to H/D exchange. Dynamic light scattering (DLS) measurements revealed the presence of associated species even below the phase transition temperature, and their fraction increased with increasing temperature. Furthermore, stereoregularity significantly affected the phase transition behavior: a heterotactic-rich polymer exhibited inverse hysteresis similar to the atactic polymer, whereas an isotactic-rich polymer showed no LCST-type phase transition. These findings suggest that hydrogen bonding between adjacent side chains, enhanced by ester carbonyl group, is responsible for the anomalous phase transition behavior of poly (NAcGlyMe).

One established method for determining the number-average molecular weight (Mn) of polymers by 1H NMR spectroscopy is based on the intensity ratio between chain-end and main-chain (repeating unit) signals. However, this method is fundamentally limited by the low signal intensity of chain-end signals and their severe overlap with main-chain signals, which hinders accurate quantification. To address these limitations, this study extends multivariate analysis (MVA)-based NMR analysis to polystyrene (PSt) Mn estimation using the aromatic region of 1H NMR spectra. In PSt, the main-chain phenyl signals dominate this region, and subtle variations in these main-chain signals may contain information related to the local environment near the chain-end. Two model polymers were designed to test this principle under contrasting conditions: BM-PSt, whose aromatic chain-end signals overlap with main-chain signals in this region, and NDM-PSt, whose aliphatic chain-end contributes no signals to this region at all. Partial least squares regression (PLS) models calibrated against Mn determined by SEC were constructed using the aromatic region (6.2–7.4 ppm) of the NMR spectra. The BM-PSt model showed high predictive performance (R2cv = 0.982), whereas the NDM-PSt model showed a moderate relationship between the spectral data and Mn, SEC (R2cv = 0.793), even though this polymer lacks chain-end signals in the aromatic region. Notably, the similarity in the PCA loading patterns between the two model polymers is consistent with the possible contribution of chain-length-dependent features of the main chain rather than specific chain-end signals. These findings provide a proof of concept that Mn-related information can be extracted from overlapping 1H NMR spectral patterns without isolating specific chain-end signals in the examined polystyrene systems.

Quantitative characterization of copolymer microstructures, including chemical composition and monomer sequences, is essential because these primary structures strongly influence material properties. In this study, we applied multivariate analysis to NMR spectra of methyl acrylate (MA)-ethyl acrylate (EA) copolymers to predict their chemical composition and monomer sequences. By applying partial least squares (PLS) regression, the MA composition was successfully predicted from 13C NMR spectra. 1H NMR spectra also provided satisfactory predictions, but 13C NMR spectra yielded more accurate results, likely because the chemical shifts of the 13C signals of the individual monomeric units were more distinct, despite spectral overlap creating an apparently featureless line shape. Monomer sequences, particularly the hetero-diad sequence, were difficult to predict using 1H NMR spectra, whereas the use of 13C NMR spectra markedly improved the prediction accuracy owing to their wider chemical shift range. This level of primary structural detail in acrylate copolymers cannot be achieved using conventional NMR analysis that relies on peak assignment and integration. These findings demonstrate that NMR spectroscopy combined with statistical multivariate analysis offers a powerful approach for determining the primary structures of acrylate copolymers.

Pressure-induced amorphization (PIA) of clathrate hydrates provides valuable insights into the fundamental properties of water and aqueous systems. We performed ab initio molecular dynamics (AIMD) simulations to elucidate the molecular-level mechanisms underlying the experimentally observed vibrational spectroscopic changes during PIA of methane hydrate (MH). The simulations successfully reproduced key experimental observations, including the blue-shift of C-H stretching vibrations with compression, the convergence of signals from small (S) and large (L) cages upon amorphization, and spectral broadening at high densities. By analyzing the correlation between vibrational spectra and methane hydration structures, we demonstrate that amorphization effectively averages the system density with respect to C-H stretching vibrations. Spectral decomposition conditioned on solvation number reveals that the broadening of C-H stretching peaks originates from the increased diversity of local solvation environments caused by cage collapse. At densities of 1.4-1.8 g cm-3, the peak position exhibits clear positive correlation with the number of proximate water molecules, whereas this correlation is negligible when the cage structure is maintained at lower densities. Analysis of metastable amorphous states at low densities demonstrates that competing effects govern the C-H stretching vibrational frequency: the approach of first-nearest-neighbor water molecules (blue-shifting) and the weakening of hydrogen bond rigidity between surrounding water molecules (red-shifting). This solvation-state-based analysis represents a key advantage of MD simulations and reveals that focusing on the number of particularly close water molecules is essential for understanding the molecular picture of PIA.

Gels are generally insoluble in solvents, making it difficult to elucidate key structural parameters, such as cross-linking efficiency and the degree of polymerization between cross-linking points. Even when cross-linking points can be selectively cleaved to convert a gel into primary polymer chains—thereby enabling structural analysis of the cross-linking sites—it remains challenging to obtain detailed information on chemical structures, including monomer sequence distribution. In this study, the cross-linking points of a styrene (St) gel cross-linked with a diacrylate were selectively cleaved via transesterification with methanol, converting the gel into a soluble styrene/methyl acrylate (St/MA) copolymer. The monomer sequence distribution of the resulting primary polymer chains was estimated by multivariate analysis of 1H NMR spectra, using separately synthesized St/MA copolymers as training data. Through this indirect approach, the chemical structures of the original gel were successfully analyzed. This strategy offers a practical route to elucidating the chemical structures of otherwise inaccessible insoluble gels.

The structure H (sH) of methane hydrate, which has a distinctive structure with large (LL) cages capable of encapsulating multiple methane molecules, has been suggested as a methane reservoir in large icy bodies such as Titan, making it important in planetary science. This high-pressure phase, which exists in the GPa range, lends itself to the study of methane states and dynamics using powerful experimental techniques such as IR and Raman spectroscopy. However, the interpretation of the vibrational spectra of methane in the sH structure has been challenging because of the spectral complexities. The signals attributed to the methane molecules in the LL cage, as well as those of the other two cage types, overlap in the spectra. In this study, we investigated the microscopic origins of the shape of the C-H stretching vibration spectrum of methane in the LL cage using ab initio molecular dynamics (AIMD) simulations. For a single methane molecule in the LL cage, the ν3 band of the C-H stretching mode was observed at a higher frequency typical of isolated molecules in vacuum due to the large size of the LL cage. As the number of methane molecules in the LL cage increased beyond one, a tendency to blue-shift with increasing methane occupancy was observed, consistent with a loose-cage-tight-cage model. By characterizing the time correlation function of methane stretching vibrations based on the solvation number of methane and water molecules proximal to methane within the LL cage, we showed that the complicated spectral line shape observed in cases of higher methane occupancy in the LL cage resulted from the wider variation of the solvation shell states. Analysis of the solvation structures of the AIMD trajectories provided interpretations of the experimental spectral line shape, demonstrating the complementary nature of AIMD to the experiment and its effectiveness in analysis.

Hydrothermal reactions of aliphatic amines have recently gained importance in relation to the application of amines as film-forming corrosion inhibitors for steam-water cycles. The kinetics and mechanism of the hydrothermal reactions of ethylammomiun cation (EtAH+) and n-octylammonium cation (OctAH+) were studied for comparison with the corresponding neutral amines to elucidate their reaction products and pathways at sub- and supercritical temperatures of 300-400 °C as model reactions of aliphatic ammonium cations. We analyzed the reaction of 13C-15N-labeled EtAH+ using NMR spectroscopy and revealed that the initial hydrolysis to ethanol, known as the main path, is followed by the elimination reaction producing ethene and the disproportionation reaction giving diethylammonium cation. The OctAH+ yields octene and octanol, each of which isomerizes to thermodynamically more stable species as the major products. Comparisons were made between the reactions of the neutral amines and ammonium cations to highlight their different reactivity. The hydrolysis, alkene formation, and dehydration of alcohols to alkenes were all found to be accelerated at low pH. The formation of low-molecular-weight organic acids such as acetic acid and formic acid was not observed. These results indicate that the corrosion protection effect of film-forming amines will be maintained under practical conditions with pH values as high as around 9 to 10, and hence side reactions involving byproducts will be suppressed.

We have presented a predictive tool for describing Pb2+ adsorption on activated carbon (AC). Based on the correlation between the G/D ratio and the adsorbed amount of Pb2+ obtained in our previous study (Kuroki et al., 2019), we have further validated the predictive tool by carefully analyzing the results of lead ion adsorption on different AC samples in the present study. Our results show that the method can predict the amount of Pb2+ adsorption within 10%, which corroborates our previous interpretation based on the hard and soft acids and bases theory. Molecular dynamic simulations were carried out to resolve the role of the counter anion and how it affects the configuration and the amount adsorbed of Pb2+ ions on the non-polar graphite surface of AC. The simulation results showed that when the counterion is NO3−, the adsorption of Pb2+ is enhanced by the electrostatic interactions of lead ions with adsorbed NO3− because NO3− is attracted strongly to the surface of graphite. This unique feature of adsorbed NO3− is substantiated with the use of Cl− as the counter anion, which did not show any significant adsorption of lead ions because chlorine ions are not strongly attracted to the surface of graphite. This mechanism is presented for the first time in the literature, and it can pave the path to exploring and understanding the complex phenomena of ions in the aqueous phase onto activated carbon.

Purpose To evaluate the tolerability, safety and efficacy of KORTUC Intratumoral injection with brachytherapy in unresectable recurrent cervical cancer. Materials and Methods A novel radiosensitizer KORTUC (Kochi Oxydol Radiation Therapy for Unresectable Carcinoma) was invested by Dr. Yasuhiro Ogawa at Kochi University (Japan) in 2006 and was developed for the treatment of malignant solid tumours that contain numerous hypoxic cancer cells and/or large quantities of antioxidative enzymes. Hydrogen peroxide is the only agent known to be capable of inactivating antioxidative enzymes and producing oxygen simultaneously when applied to tumour tissues. KORTUC is a solution that contains 3% hydrogen peroxide with 1% sodium hyaluronate. Hydrogen peroxide is the active ingredient for this radiosensitizer. Sodium hyaluronate viscosity sustains the hydrogen peroxide in the tumour as well as delays decomposition of hydrogen peroxide and maintains a high concentration of oxygen in the tumour. Injecting the two components together at a particular ratio is the key feature of this product. Currently Phase 2 clinical trial for locally advanced and recurrent breast cancer has been conducted in the United Kingdom and India. Our institution, (Osaka Medical and Pharmaceutical University, Japan) has conducted single-arm clinical research of KORTUC since May 2010, we dosed KORTUC more than 250 patients of various solid cancers including more than 40 patients of the gynecological tumors treated with brachytherapy as of today. In this study we report our experiences of KORTUC with brachytherapy in recurrent local advanced cervical cancer patients who are likely the high risk of poor prognosis.From April 2012 to January 2020, 15 female patients with recurrent cervical cancer received KORTUC with brachytherapy. Previous treatments of 15 recurrent patients were surgery (n=4), radiation therapy (n=8), surgery + radiation therapy (n=3). The primary lesion of these 15 patients were vaginal stump (n=5), pelvic wall (n=3), cervix (n=3), vaginal wall (n=2), and lymph node (n=2). KORTUC was injected intratumorally under direct vision of colposcopy prior to radiation therapy. The dose of KORTUC ranged from 4 to 12 mL adjusted by tumor size. For patients who had the Interstitial brachytherapy, KORTUC was administered before and after the applicator insertion prior to irradiation. Results Intratumoral injection of KORTUC was completed without any technical and safety issues in all 15 patients. KORTUC was well tolerated and no adverse events judged to be related to KORTUC injection were observed, except the transient local pain at the injection site in some patients. KORTUC also showed efficacy in local control in recurrent patients. Conclusion Based on this result, we would like to confirm in a future study, KORTUC's efficacy with external irradiation as well as brachytherapy for the newly diagnosed unresectable locally advanced cervical cancer with high risk factors of poor prognosis. KORTUC may have potential as an effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor.

The structure of thefilm formed by oleylpropanedi-amine (OLDA) on the copper (Cu) metal surface in water at 150 degrees C was investigated by combining quantitative NMR and surfacecharacterization methods. We succeeded in quantifying the amountoffilm formation by precisely determining all mass balances in thesystems examined. 2D IR microscopic mapping showed that thefilm thickness is uneven in the horizontal direction with a lengthscale of similar to 100 mu m and hundreds of OLDA layers. Thisfilmthickness was also confirmed by AFM. The analysis of the C-Hstretching vibrational frequency disclosed that the alkyl chains arehighly ordered in the layers close to the Cu surface and areconformationally disordered in the layers distant from the Cusurface in the thicker portion of thefilm. Combining XPS measurements using argon gas cluster ion beam etching with the ICP-AESanalysis, we revealed that the key to multiple layering is the formation of a coordination complex of the unprotonated amino groupsof OLDA with Cu that presumably results in polymer chain-like network structures. Contact angle measurements at different OLDAconcentrations and treatment times showed that the water repellency of thefilm originated from the thick layering of OLDAmolecules with disordered hydrophobic chains.

Our recent experimental study of water adsorption in micro-mesoporous carbons at 263 K and 298 K show an unusual temperature dependence of adsorbed density with higher loading at 298 K at the same reduced pressure. The difference is in the filling of mesopore at 298 K and its absence at 263 K, and it was conjectured to the growth of water clusters on the functional groups in the confined space of mesopores in which the water clusters at 298 K are sufficiently large to induce the subsequent filling. Since the growth of these clusters and their coalescence is the prerequisite for filling, the filling is absent at 263 K simply because of the smaller size of the clusters, preventing them from coalescence and hence, no filling. In a quest to understand the effects of temperature on water adsorption in micro-mesoporous carbon, we used molecular dynamic simulation to reveal the mechanism of water adsorption around functional groups from 263 K to 328 K to clarify the growth of the water cluster as a function of temperature. The results clearly show that the water cluster is larger at 298 K compared to 263 K, confirming the conjecture from our previous works. (C) 2021 The Author(s). Published by Elsevier Ltd.

A N-14 and H-1 NMR spectroscopic study was carried out to shed light on microscopic aspects of the reaction of model alkylamines at a supercritical temperature of 400 degrees C. It is disclosed that NH3 and ROH (R = CH3CH2 and CH3 (CH2)(3)) are initially produced from the hydrolysis of ethylamine and butylamine, respectively. When the water density is doubled from 0.2 g cm(-3), the pseudo-first-order reaction rate is markedly enhanced beyond the linear response. It suggests that the transition state of the C-N bond cleavage is in a dipolar (ionic) state that can be more stabilized due to the many-body solvation by highly polar water molecules at a higher density.

The translational dynamics of water and cyclohexane in supercritical binary mixtures were investigated using molecular dynamics simulations. The effects of the local composition were examined through a decomposition scheme of the conditional time-correlation functions based on the solvation numbers for water and cyclohexane. The self-diffusion of water was found to be largely controlled by the continuous and collective attractive interactions with surrounding water molecules, while interactions with cyclohexane have minimal impact on water diffusion. On the other hand, the self-diffusion of cyclohexane is dominantly determined by uncorrelated collisional interactions with neighboring cyclohexane molecules. The results demonstrate the dynamic aspect of microscopic inhomogeneity and highlight the significance of interactions between molecules of the same species. An examination of the dependence of self-diffusion on the lifetime of the solvation shell indicated that the self-diffusion of water is confined within the solvation shell. This is attributed to the hydrogen bond interactions with neighboring water molecules, which create an energy barrier to the water molecules diffusing out of the hydration cage. In contrast, diffusing cyclohexane molecules migrate beyond the solvation shell, particularly at large water contents.

The self-diffusion coefficients of water (Dw) and cyclohexane (Dch) in their binary mixtures were determined using the proton pulsed field gradient spin-echo method from medium to low densities in subcritical and supercritical conditions. The density (ρ), temperature (T), and water mole fraction (xw) are studied in the ranges 0.62-6.35 M (M = mol dm-3), 250-400 °C, and 0.109-0.994, respectively. A polynomial fitting function was developed for a scaled value of Ξ = ρDT-1/2 with ρ, T, and xw as variables in combination with a comprehensive molecular dynamics (MD) simulation. The NMR and MD results agree within 5% for water and 6% for cyclohexane, on average. The differences between Dw and Dch in the dependence on ρ, T, and xw are characterized by the activation energy Ea and the activation volume ΔVΞ ‡ expressed by the scaled fitting function. The decrease in the ratio Dw/Dch and the increase in the Ea of water with increasing xw are related to the increase in the number of hydrogen bonds (HBs). The Dw value for a solitary water molecule at a low xw is controlled by the solvation shell, most of which is occupied by nonpolar cyclohexane molecules that provide less friction as a result of weaker interactions with water. A microscopic diffusion mechanism is discussed based on an analysis of the HB number as well as the first-peak height of the radial distribution functions that are taken as measures of the potential of the mean field controlling self-diffusion.

The solution-state NMR measurement of a synthetic polymer in sub-critical fluids has been accomplished by taking advantage of the specially-designed high-pressure and high-temperature NMR probe. The purpose here is to overcome the signal broadening typically occurring in conventional solution-state NMR due to the slow dynamics of polymers at room temperature. A remarkable sharpening of the 1H NMR signal was observed for poly (N-vinyl-2-pyrrolidone) dissolved in D2O at 250°C. This result has encouraged us to apply high-temperature NMR methods to polymers, such as copolymers, whose spectra were too complicated to be deconvoluted by means of conventional procedures.

No pulmonary or cardiac toxicity was observed.Although the series is not homogeneus, there was no significant difference in the incidence of acute or late toxicity in pts that underwent or not to chemotherapy. ConclusionIn our seriesHRT is well tollerated with a good toxicity profile and a good cosmetic result.There is no clear evidence that chemotherapy has an impact to acute or late skin toxicity after HRT.In our analysis we can not evaluate the role that have sequential boost in causing late toxicity.