High Resolution Solid State Research Articles

Achalasia: diagnostic delay and manometric characteristics with high-resolution solid-state and perfusion equipment.

The early diagnosis of achalasia requires a high degree of clinical suspicion, and delays in diagnosis are frequent. High-resolution oesophageal manometry (HRM) is the gold standard for its diagnostic confirmation. There are two HRM systems, perfusion and solid-state, which allow its classification into three subtypes: I, or classical; II, or with pan-oesophageal pressurization; and III, or spastic. To determine the clinical and manometric characteristics of the three subtypes with high-resolution perfusion and solid-state equipment and the time of evolution until diagnosis. This was a multicentre, observational, retrospective study of patients from the INTEGRA database of the Spanish Association of Neurogastroenterology and Motility who were diagnosed with primary achalasia confirmed by HRM, who fell under the Chicago Classification v3.0, and who had not been treated. The study included 110 patients (subtype I, N = 14; subtype II, N = 73; subtype III, N = 23). The HRM equipment was perfusion for 49 and solid-state for 61. The mean age was 61.8 ± 14 years (age range 44-81), the age was lower in subtype II, and the sex distribution was similar. The time of clinical evolution until diagnosis was > 12 months (51.6%), subtype II being the one that was diagnosed earlier and the most often (66.3%). Dysphagia was the most frequent symptom (90.5%). According to the comparative analysis by high-resolution perfusion and solid-state oesophageal manometry equipment, the baseline pressure of the lower oesophageal sphincter was higher in the solid-state oesophagus, but the difference was not statistically significant. The median integrated relaxation pressure at 4 seconds (IRP4) was similar (21 mmHg) between the perfusion and solid-state measurements. We describe the ranges of IRP4 in achalasia patients with both systems and confirm the possibility of achalasia even when IRP4 is within the normal range. Achalasia in our environment has a significant diagnostic delay. No significant differences were observed in the oesophagogastric junction between the two groups diagnosed with perfusion and solid-state equipment.

High-Resolution 17O Solid-State NMR as a Unique Probe for Investigating Oxalate Binding Modes in Materials: The Case Study of Calcium Oxalate Biominerals.

Oxalate ligands are found in many classes of materials, including energy storage materials and biominerals. Determining their local environments at the atomic scale is thus paramount to establishing the structure and properties of numerous phases. Here, we show that high-resolution 17O solid-state NMR is a valuable asset for investigating the structure of crystalline oxalate systems. First, an efficient 17O-enrichment procedure of oxalate ligands is demonstrated using mechanochemistry. Then, 17O-enriched oxalates were used for the synthesis of the biologically relevant calcium oxalate monohydrate (COM) phase, enabling the analysis of its structure and heat-induced phase transitions by high-resolution 17O NMR. Studies of the low-temperature COM form (LT-COM), using magnetic fields from 9.4 to 35.2 T, as well as 13C-17O MQ/D-RINEPT and 17O{1H} MQ/REDOR experiments, enabled the 8 inequivalent oxygen sites of the oxalates to be resolved, and tentatively assigned. The structural changes upon heat treatment of COM were also followed by high-resolution 17O NMR, providing new insight into the structures of the high-temperature form (HT-COM) and anhydrous calcium oxalate α-phase (α-COA), including the presence of structural disorder in the latter case. Overall, this work highlights the ease associated with 17O-enrichment of oxalate oxygens, and how it enables high-resolution solid-state NMR, for "NMR crystallography" investigations.

Structure, Location, and Spatial Proximities of Hydroxyls on γ-Alumina Crystallites by High-Resolution Solid-State NMR and DFT Modeling: Why Edges Hold the Key

The atomic-scale characterization of surface active sites on γ-alumina still represents a great challenge for numerous catalytic applications. Here, we combine advanced density functional theory (DFT) calculations with one- and two-dimensional proton solid-state NMR experiments to identify the exact location and the spatial proximity of hydroxyl groups on γ-alumina crystallites. Our approach relies on revisited models for the (100), (111), basal (110)b, and lateral (110)l facets of γ-alumina, as well as for the edges at their intersections. Notably, we show that the ≃0 ppm AlTd-μ1-OH protons are predominantly located on edges, where these are free from the H-bond network. The proximities among the AlTd-μ1-OH as well as with μ2-OH groups are revealed by 1H–1H dipolar correlation experiments and analyzed in the light of the DFT calculations, which identify their location on the basal (110)b facet and on the (110)b/(100) and (110)b/(110)l edges. Using chlorine atoms to probe the presence of hydroxyls, we show that the chlorination occurs selectively by exchanging μ1-OH located on edges and on lateral (110)l facets. By contrast, the basal (110)b and lateral (111) facets are not probed by Cl. This exchange explains the disappearance of the ≃0 ppm peak and of the correlations involving AlTd-μ1-OH species. Moreover, after chlorination, a deshielding of the AlTd is observed on high-resolution 27Al NMR spectra. More subtle effects are visible on the proton correlation spectra, which are attributed to the disruption of the H-bond network in the course of chlorination.

A Low-Cost High-Resolution Solid-State Lidar With Wavelength Division Multiplexed Components and Interleaved Orthogonal Polarization Grating Couplers

Laser diodearray and photo diode array combined through coarse wavelength division multiplexed (CWDM) are widely used in short-reach optical communication within massive web-scale data center. Those components can be used in solid-state photonics-based Lidar built upon silicon-on-insulator (SOI) waveguide as well, achieving significant cost saving. Beam steering can be naturally achieved through diffraction in output grating couplers. However, current design is hampered by low angular resolution. We demonstrate a novel design by combining outputs of two grating couplers with orthogonal polarizations in an interleaving manner. This scheme effectively doubles the angular resolution of on-chip Lidar.

Atomic-Level Structure of Mesoporous Hexagonal Boron Nitride Determined by High-Resolution Solid-State Multinuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations

Mesoporous hexagonal boron nitride (p-BN) has received significant attention over the last decade as a promising candidate for water cleaning/pollutant removal and hydrogen storage applications. Here, high-resolution solid-state NMR spectroscopy and plane-wave density-functional theory (DFT) calculations are used to obtain an atomic-level description of p-BN. 1H–15N or 1H–14N heteronuclear (HETCOR) correlation experiments recorded with either conventional NMR at room temperature or dynamic nuclear polarization surface-enhanced spectroscopy (DNP-SENS) at ca. 100 K reveal NB2H, NBH2, NBH3+ species residing on the edges of BN sheets. Ultra-high field 35.2 T 11B NMR spectroscopy was used to resolve 11B NMR signals from BN3, BN2Ox(OH)1–x (x = 0–1), BNOx(OH)2–x (x = 0–2), BOx(OH)3–x (x = 0–3), and BOx(OH)4–x– (x = 0–4). Importantly, 2D 11B dipolar double-quantum–single-quantum homonuclear correlation spectra reveal that many pore/defect sites are composed of boron oxide/hydroxide clusters connected to the BN framework through BN2O units. 1D and 2D 11B{15N} HETCOR NMR experiments, in addition to plane-wave DFT calculations of nine different structural models, further confirm the assignment of all NMR signals. The detailed structure determination of the pore and edge/defect sites within p-BN should further enable the rational design and development of next-generation p-BN-based materials. In addition, the techniques outlined here should be applicable to determine structure within other porous and/or boron-based materials.

高分解能固体NMR法およびガス分析による石炭低温酸化反応機構の解析

高分解能固体NMR法およびガス分析による石炭低温酸化反応機構の解析

The Atomic-Level Structure of Mesoporous Hexagonal Boron Nitride Determined by High-Resolution Multinuclear Solid-State NMR Spectroscopy and DFT Calculations

The Atomic-Level Structure of Mesoporous Hexagonal Boron Nitride Determined by High-Resolution Multinuclear Solid-State NMR Spectroscopy and DFT Calculations

Structural Refinement of Carbimazole by NMR Crystallography.

The characterization of the three-dimensional structure of solids is of major importance, especially in the pharmaceutical field. In the present work, NMR crystallography methods are applied with the aim to refine the crystal structure of carbimazole, an active pharmaceutical ingredient used for the treatment of hyperthyroidism and Grave’s disease. Starting from previously reported X-ray diffraction data, two refined structures were obtained by geometry optimization methods. Experimental 1H and 13C isotropic chemical shift measured by the suitable 1H and 13C high-resolution solid state NMR techniques were compared with DFT-GIPAW calculated values, allowing the quality of the obtained structure to be experimentally checked. The refined structure was further validated through the analysis of 1H-1H and 1H-13C 2D NMR correlation experiments. The final structure differs from that previously obtained from X-ray diffraction data mostly for the position of hydrogen atoms.

Combined High-Resolution Solid-State 1H/13C NMR Spectroscopy and 1H NMR Relaxometry for the Characterization of Kerogen Thermal Maturation

A key factor for the petroleum potential of source rock is the degree of chemical and physical structure evolution of its kerogen fraction through a range of maturation processes. In this study, various high-field, solid-state NMR methods have been applied to a series of kerogen isolates (type I) over a defined maturity range (vitrinite reflectance R₀ from 0.98 to 1.86%). Results obtained from ¹³C MAS NMR show that the sp²/sp³-hybridized carbon ratio of kerogen, here defined as the aromatic/aliphatic ratio, increases with increasing maturity. ¹H MAS NMR spectra contain partly overlapping aliphatic and aromatic resonances with distinct transverse relaxation behavior. In Hahn-echo experiments, the aromatic signal decays more slowly than the aliphatic signal, indicating that for these systems, transverse ¹H relaxation is rather controlled by local distances between hydrogen atoms than by molecular mobility. Similar relaxation differences are also found in static (nonspinning) ¹H Hahn-echo NMR experiments, here used to discriminate between phases with different proton mobilities and/or densities in the kerogen samples and, ultimately, between aromatic and aliphatic fractions. The distributions of the static transverse relaxation time (T₂), extracted from the Hahn-echo decays, are characterized by a short-T₂ peak (∼10 μs) and a long-T₂ peak (∼100 μs). The ratio between these two peaks correlates well with the aliphatic-to-aromatic signal intensity ratios in MAS NMR spectra of the corresponding kerogen samples, suggesting that a net decrease in kerogen proton density—occurring during maturation—is also reflected by ¹H NMR relaxation. For the investigated kerogen isolates, the long-T₂ peak in the T₂ distribution can be considered an indicator of aromatic content, which can be directly detected by measuring ¹H T₂ relaxation.

On the Rational Drug Design for Hypertension through NMR Spectroscopy.

Antagonists of the AT1receptor (AT1R) are beneficial molecules that can prevent the peptide hormone angiotensin II from binding and activating the specific receptor causing hypertension in pathological states. This review article summarizes the multifaced applications of solid and liquid state high resolution nuclear magnetic resonance (NMR) spectroscopy in antihypertensive commercial drugs that act as AT1R antagonists. The 3D architecture of these compounds is explored through 2D NOESY spectroscopy and their interactions with micelles and lipid bilayers are described using solid state 13CP/MAS, 31P and 2H static solid state NMR spectroscopy. Due to their hydrophobic character, AT1R antagonists do not exert their optimum profile on the AT1R. Therefore, various vehicles are explored so as to effectively deliver these molecules to the site of action and to enhance their pharmaceutical efficacy. Cyclodextrins and polymers comprise successful examples of effective drug delivery vehicles, widely used for the delivery of hydrophobic drugs to the active site of the receptor. High resolution NMR spectroscopy provides valuable information on the physical-chemical forces that govern these drug:vehicle interactions, knowledge required to get a deeper understanding on the stability of the formed complexes and therefore the appropriateness and usefulness of the drug delivery system. In addition, it provides valuable information on the rational design towards the synthesis of more stable and efficient drug formulations.

Dynamics and Proton Transport in Imidazole-Doped Nanocrystalline Cellulose Revealed by High-Resolution Solid-State Nuclear Magnetic Resonance Spectroscopy

CNC-Im is a new proton conductor based on imidazole-functionalized nanocrystalline cellulose with a conductivity of about 10-1 S/m at 160 0C. Its conductivity is possible due to the transport of pr...

Input of solid‐state 13C NMR to study permeation of wet archaeological bones by dicarboxylic fatty diacid‐based chemicals

Conservation treatment of degraded archaeological osseous materials is still an open challenge, since no specific conservation protocol is currently available for restorers or museum curators. This work aims to test the efficiency of two original consolidant solutions in consolidating archaeological material. Archaeological osseous materials remain rare and sparsely available, it is a real drawback for optimization of conservation treatments, therefore in the present work a set of representative samples was chosen. The consolidants tested were a solution of disodium sebacate and a novel polyalcohol (SG1.2) obtained by esterification of 5 succinic diacids with 6 molecules of glycerol at 150°C. Characterization studies of archaeological bones, combining SEM microscopy, IR spectroscopy and high-resolution solid-state 13 C NMR investigations, have been carried out to assess the effective permeation of bone by the consolidant solutions and to determine their chemical interactions with the residual components of archaeological bones. Although both water solutions significantly impregnate bone, we show that, the solution with disodium sebacate leads to chemical attack on the mineral component due to preferential precipitation of endogenous calcium by the sebacate ions. Such deleterious behaviour is not observed at all with the SG1,2 chemicals. The added value of the polyalcohol treatment as strengthening agent suitable for archaeological bony materials should be further demonstrated by mechanical and ageing tests.

Strikingly different molecular organization and molecular order of tetracatenar mesogens in columnar mesophases revealed by XRD and 13C NMR.

For a successful design of functional mesogens, it is paramount to understand factors that contribute to molecular organisation such as molecular shape, the non-covalent interactions of the constituent moieties as well as nanosegregation of incompatible molecular parts. In this study on four tetracatenar mesogens, we show that by a slight change in the length of the terminal chain, the molecular organization changes from lamellar to columnar phase and that the orientational order experiences profound change between the lamellar, the center rectangular columnar and the hexagonal columnar mesophases. We consider here, mesogens that exhibit lamellar and columnar mesophases with five phenyl rings in the central rod-like core which are subjected to XRD and high resolution solid state 13C NMR investigations in their mesophases. The XRD studies indicate that the lower homologs exhibit a lamellar mesophase while the higher homologs show either a centre rectangular columnar phase or a 2D hexagonal columnar mesophase. 13C NMR investigations reveal interesting and strikingly different molecular orientations in each of these phases. For example, values of order parameters of one of the phenyl rings in the core region of the mesogens vary from 0.75 and 0.77 for the lamellar mesogens to 0.45 and 0.17 for the centre rectangular columnar and the hexagonal columnar mesogens respectively. While these values indicate that the mesogenic molecules are oriented along the magnetic field as expected in the lamellar phases, the very low order parameter in the hexagonal columnar phase arises due to molecules distributed azimuthally in layers and undergoing motion about the columnar axis which itself is oriented orthogonal to the magnetic field. Such cutting edge information extracted from the combined use of XRD and 13C NMR studies on tetracatenar mesogens is expected to be of significant use for the study of π-conjugated polycatenar systems where functional properties depend on the molecular orientation and order.

An Overview of Analytical Methods for in Vitro Bioassay of Actinides.

The bioassay of urine and fecal samples has been used since the 1940s to determine an individual's uptake of uranium and actinide elements such as americium and plutonium. Over the years, several analytical separation methods and techniques have been employed for these types of analyses. Analytical separations, ranging from solvent extraction and anion exchange to chromatography, and analytical techniques, ranging from autoradiography to kinetic phosphorescence to fission-track analysis and high-resolution solid-state alpha spectroscopy, have been used at one time or another. Over the last few decades, there have been significant advances in radiochemical separations, as well as an increased use of mass spectroscopy, to determine trace and ultratrace levels of actinides in urine and fecal samples. This review summarizes and discusses developments in radiochemical separation methods and advancements in analytical techniques for actinide bioassay since the early 1940s to the present, followed by a recent development and trend in the bioassay of actinides-particularly in urine and fecal samples.

Application of cognitive education in esophageal high resolution manometry examination

Objective To explore the effect of cognitive education and behavioral intervention in solid-state high resolution esophageal manometry (HRM) examination. Methods From April 2016 to June 2017, 60 patients with solid-state HRM in the gastrointestinal motility room at the First Affiliated Hospital of Jiaotong University were as the research object. The 60 patients were divided into control group and experimental group with 30 cases each by the method of random numbers. The conventional methods was used in control group to conduct informed counseling before the examination and the coordination guidance in the examination. The conventional methods and cognitive behavioral intervention was used in experimental group at the same time. The successful rate of intubation, the time used for the examination, discomfort symptoms during intubation, the patient′s satisfaction in the whole check process and self-evaluation of intubation pain experience in two groups of patients were compared. Results The time used in the experimental group examination was (28.50±8.75) min, and the control group was (33.13±5.49) min. The difference between the two groups was statistically significant (t=2.584, P=0.015). In the experimental group, the number of nausea, vomiting, and coughing in the intubation process was 11, 0, and 1, respectively, and the control group was 20, 6, and 7, respectively. The difference was statistically significant (χ2=5.406, 4.630, 5.192, all P<0.05). In the experimental group, the scores of the 2, 3, 4, 5, 7, 8, 10, 11, 12, and 13 items of the intubation pain experience self-evaluation in the examination process were (1.00±0.64), (1.37±0.85), (2.80±0.96), (1.50±0.51), (0.87±0.63), (0.77±0.50), (0.60±0.56), (1.07±0.25), (0.57±0.57), (1.50±0.63) points, and the 2, 3, 4, 5, 7, 8, 10, 11, 12 and 13 scores of the control group they were (1.50±0.51), (2.03±0.76), (3.50±0.82), (2.03±0.76), (1.20±0.61), (1.03±0.41), (0.83±0.53), (1.23±0.43), (0.87±0.57), (2.00±1.05) points, respectively. The difference was statistically significant (t=-4.130--2.140, all P<0.05). Conclusions HRM is an important test before the clinical application of a wide range of clinical applications for the detection of esophageal motility disorders and gastroesophageal reflux disease. The degree of patient cooperation with the operation directly affects the high-resolution esophageal manometry test results and self-experience. Medical staff can give patients cognitive education and behavioral intervention before examination, which can effectively reduce the symptoms and pain caused by intubation, improve patient compliance, shorten the time for examinations, improve work efficiency, and improve patient satisfaction. It is worth further promotion and application in clinical examination. Key words: Cognitive education; Behavioral intervention; High resolution esophageal pressure; Intubation discomfort; Satisfaction

Elucidating the internal structure and dynamics of [formula omitted]chitin by 2DPASS-MAS-NMR and spin-lattice relaxation measurements

The structure and dynamics of the second most abundant biopolymer α−chitin were studied by high resolution solid state 13C cross-polarization magic angle spinning nuclear magnetic resonance (CP-MAS-NMR) spectral analysis, 13C relaxation measurements at eight chemically different carbon sites and chemical shift anisotropy measurement by two-dimensional phase-adjusted spinning sidebands (2DPASS) magic angle spinning (MAS) solid state NMR method.13C spin-lattice relaxation time was measured by high resolution Torchia CP method. Spin-lattice relaxation rate (1/T1) of side chain carbon nuclei were remarkably high, because those nuclei possess higher degree of motional freedom. Chemical shift anisotropy parameters of eight chemically different carbon nuclei were determined by 2DPASS-MAS-NMR experiment. Large value of chemical shift anisotropy was observed for carbonyl group carbon (C7) nuclei, because of electrostatic effect, hydrogen bonding and molecular magnetic susceptibility. 13C relaxation mechanism is mainly governed by chemical shift anisotropy interaction, especially at high value of external magnetic field (11.74 T). Thus, the correlation time at different carbon sites were also calculated by using the spin-lattice relaxation times and chemical shift anisotropy values. The correlation time of side chain carbon (C8) was two orders of magnitude less than the carbonyl group carbon. These types of investigations would enlighten the correlation between the structure and dynamics of long polysaccharide chain compound.

Direct observation of the effects of small-amplitude motions on 13C nuclear shielding tensors by means of low-temperature 2D MAS NMR spectroscopy

Fast small-amplitude motions, such as vibrations or librations, do affect NMR properties of molecules in the solid state. The quantification of these effects is very important for structural studies exploiting Solid State NMR and computational methods, particularly in the field of NMR crystallography. In this work 2D MAS NMR experiments were carried out over a wide range of low temperatures (129–295 K) on a non-standard high-resolution Solid State NMR equipment to obtain the first experimental determination of the effects of small-amplitude motions on 13C Chemical Shift Tensors of a multi-carbon molecule (ibuprofen).

Ionic conductivity of lithium borate glasses and local structure probed by high resolution solid-sate NMR

Structural properties and ionic conductivity have been correlated in the XLi2O-(100 − X)B2O3 vitreous system over a wide range of composition (X = 0–50 mol%). The structural evolution of the vitreous network as a function of the lithium oxide content was established at ambient temperature by 11B and 7Li high resolution solid state NMR, while electrical conductivity has been measured by complex impedance spectroscopy from room temperature up to the glass transition temperature Tg. The 11B NMR spectra indicate that starting from pure boron trioxide glass, the addition of alkali leads to a gradual transformation of BO3 units into BO4−. From X ≈ 30, the increase of Li+ content is also accompanied by the formation of Non-Bridging Oxygen (NBO). These specific structural changes have been used to interpret the conductive behavior of vitreous lithium borates. Indeed, measured on a wide range of composition, the direct conductivity (σdc) increases with the Li2O content and exhibits a clear regime change at X ≈ 32, which can be correlated to the interaction of cations with BO4− units and NBO.

β-Cyclodextrin-epichlorohydrin polymer/graphene oxide nanocomposite: preparation and characterization

In this study, we report a novel and simple technique to synthesize water-insoluble nanocomposite macromolecule composed of graphene oxide (GO) nanosheets and β-cyclodextrin (β-CD) polymer. These nanocomposites were synthesized by the one-pot precipitation polymerization process via polycondensation of β-CD with epichlorohydrin (ECH) in an aqueous suspension of GO under alkaline condition. The obtained β-CD polymer/GO (CDP-ECH/GO) were characterized by thermal gravimetry, differential scanning calorimetry, infrared and Raman spectroscopies, high-resolution solid state 13C NMR, X-ray diffraction, electron microscopy (both SEM and TEM), and energy dispersive spectroscopy. Furthermore, the mechanism of CDP-ECH/GO nanocomposites formation is also discussed depending on the type of mixing device that has been used during polymerization. The swelling ratio of the nanocomposites as well as their absorption properties toward methylene blue (MB), phenol (PN), 1-naphtol (1-NPH) and 2-naphtol (2-NPH) have been determined. Increasing the GO content in the nanocomposites results in an increase of the adsorption capacity of the materials.

Multiheterodyne spectroscopy using interband cascade lasers

While mid-infrared radiation can be used to identify and quantify numerous chemical species, contemporary broadband mid-IR spectroscopic systems are often hindered by large footprints, moving parts and high power consumption. In this work, we demonstrate multiheterodyne spectroscopy using interband cascade lasers, which combines broadband spectral coverage with high spectral resolution and energy-efficient operation. The lasers generate up to 30 mW of continuous wave optical power while consuming less than 0.5 W of electrical power. A computational phase and timing correction algorithm is used to obtain kHz linewidths of the multiheterodyne beat notes and up to 30 dB improvement in signal-to-noise ratio. The versatility of the multiheterodyne technique is demonstrated by performing both rapidly swept absorption and dispersion spectroscopic assessments of low-pressure ethylene (C$_2$H$_4$) acquired by extracting a single beat note from the multiheterodyne signal, as well as broadband multiheterodyne spectroscopy of methane (CH$_4$) acquired with all available beat notes with microsecond temporal resolution and an instantaneous optical bandwidth of 240 GHz. The technology shows excellent potential for portable and high-resolution solid state spectroscopic chemical sensors operating in the mid-infrared.