Search Results (39)

Porous three-dimensional reduced graphene oxide (3DrGO) combines a hierarchical pore network with tunable surface chemistry, making it an attractive material for applications involving mass transport and interfacial phenomena. In this work, the pore structure and surface properties of 3DrGO were investigated using conventional and low-field nuclear magnetic resonance (NMR) techniques. Scanning electron microscopy (SEM), N₂ adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS), Carr-Purcell-Meiboom-Gill (CPMG) NMR relaxometry, and Fast Field Cycling (FFC) NMR relaxometry were employed to characterize the material over multiple length scales and probe confined liquid dynamics. While SEM and gas adsorption resolved the macro- and mesoporous structure, CPMG relaxometry revealed several confined liquid populations. Comparison of the NMR relaxation and XPS data suggested that the abundance of oxygen-containing surface groups contributes to differences between polar and nonpolar molecule-surface interactions, with stronger apparent interactions for polar liquids. The desorption behavior was consistent with nonuniform liquid coverage under partially saturated conditions. Analysis of NMR dispersion profiles further indicated a rough, chemically heterogeneous surface, highlighting the potential of low-field NMR techniques as powerful tools for correlating pore architecture, surface chemistry, and molecular dynamics in porous 3DrGO. Full article

Temporally correlated flux-induced phase noise can influence superconducting-quantum-circuit execution in ways that are not fully captured by uncorrelated, memoryless, or gate-averaged noise models. In this work, we develop an execution-oriented, circuit-level workflow for modeling and evaluating such effects. The workflow combines source-specific circuit-level noise components with a phenomenological segmented correlation-time construction for flux-induced phase noise, thereby enabling explicit control of a tunable correlation-time parameter ${\tau }_c$ within a composite circuit-level noise model. Using a single-qubit Carr–Purcell–Meiboom–Gill (CPMG) sequence and standard randomized benchmarking as the representative single-qubit circuit settings, we evaluate how circuit outputs respond to temporally correlated flux-induced phase noise under otherwise matched simulation conditions. The results show that temporally correlated flux-induced phase noise produces circuit-level behavior that differs qualitatively from uncorrelated or memoryless descriptions, and that its impact is governed jointly by the correlation-time parameter ${\tau }_c$, the temporal structure of the circuit, and the way in which the circuit samples the noise. The proposed workflow provides a circuit-level framework for analyzing temporally correlated noise in superconducting quantum computing. Full article

Background/Objectives: Ketogenic diets induce profound metabolic reprogramming; however, their impact on systemic metabolism in patients with hepatic fibrosis remains insufficiently characterized. This study aimed to investigate serum metabolic changes induced by Very Low Energy Ketogenic Therapy (VLEKT) and to assess the influence of hepatic fibrosis development on these metabolic adaptations. Methods: Fifty serum samples from 25 obese patients were analyzed using 1D 1H CPMG NMR spectroscopy at baseline (T0) and after 8 weeks of VLEKT (T1). Patients were stratified according to the FIB-E fibrosis index into a low-risk group (LR; FIB-E < 8) and an intermediate-high-risk group (IHR; FIB-E ≥ 8) for hepatic fibrosis onset. Results: An integrated approach combining NMR-based metabolomics and pathway enrichment analysis revealed a marked metabolic shift following VLEKT, characterized by increased ketone bodies (including β-hydroxybutyric acid and acetone), together with changes in amino acids and lipid-related signals. Among these, acetone provided a robust and quantifiable NMR signal, consistent with enhanced ketogenesis. Stratified analysis indicated differential metabolic flexibility: LR patients exhibited enhanced modulation of tricarboxylic acid (TCA) cycle-related metabolites, whereas IHR patients showed persistent alterations in aromatic amino acids and lipid signals. Significant correlations between tyrosine and β-alanine with clinical biochemical markers further supported the presence of a fibrosis-dependent metabolic signature. Conclusions: These findings highlight the potential of circulating metabolites as sensitive and non-invasive indicators of hepatic vulnerability and determinants of metabolic adaptability to VLEKT. Moreover, the study underscores the value of NMR-based metabolomics as an innovative tool for improving the non-invasive assessment of metabolic and hepatic health. Full article

Online monitoring of polyacrylamide (PAM) concentration is needed for quality control in continuous fracturing-fluid blending and for closed-loop smart fracturing operations. This study evaluates the feasibility and current limits of an MR-based PAM assay route. Static CPMG-T2 tests on an existing 4.6 MHz magnetic resonance multiphase flowmeter (MRMF) platform showed that T2-based viscosity discrimination is useful when the PAM concentration is above approximately 3‰, but it becomes insufficient in the 1–3‰ low-concentration interval. A 20 MHz laboratory T2-D validation test indicated that the apparent diffusion coefficient responds more clearly to PAM-induced molecular-mobility variation than T2 alone. On this basis, a 23.5 MHz diffusion-capable online detector concept was developed, featuring a permanent-magnet module, a gradient-capable RF probe, compact spectrometer electronics, and a quasi-static bypass sampling process for oilfield installation. The revised interpretation framework combines T1, T2, diffusion coefficient, temperature, signal-quality indicators, repeatability checks, and calibration-domain gating. The present work defines a proof-of-concept route, and the validation requirements for online PAM concentration monitoring; final accuracy, repeatability, RMSE, confidence intervals, and field-calibrated acceptance thresholds must still be determined through controlled loop and field tests. Full article

Background/Objectives: Studying the role of UV-induced metabolic changes in skin physiology, and especially skin diseases, has gained importance in both medicine and cosmetics. With the development of new technologies, a variety of approaches have been implemented to model these metabolic effects. In this study, we explore the reproducibility of the UVA1-induced metabolic changes observed in different in vitro, ex vivo, and in vivo systems with escalating complexity. Our aim is to elaborate on the role of experimental setups in the reliable representation of in vivo data in other systems. Methods: Metabolic profiles post UVA1 treatment were assessed in skin cell culture, skin explants, and intact skin. For cell culture and explants, the metabolites from the culture medium were assessed via 1D-CPMG NMR. Intact skin samples were collected via microdialysis and the resulting dialysate was measured with GC–TOF-MS. Results: Data show that, despite great metabolic variations between the systems, several metabolites, such as glutamic acid, succinic acid, and threonine, change in a similar manner across multiple systems after UVA1 irradiation, including in vivo settings. Some metabolites, like phenylalanine, citric acid, and pyruvic acid, show similar UVA-mediated metabolic patterns between corresponding in vitro and ex vivo systems, but do not overlap well with in vivo data. Conclusions: Our findings emphasize the need for a metabolite-by-metabolite approach when deciding on the proper experimental system to perform UV irradiation experiments with regard to cutaneous physiology. Full article

This protocol paper outlines a robust and reproducible framework for a ¹H nuclear magnetic resonance (NMR) metabolomics analysis of rodent plasma, designed to facilitate preclinical biomarker discovery. The protocol details optimised steps for plasma collection in a preclinical rodent model, sample preparation, and NMR data acquisition using presaturation Carr–Purcell–Meiboom–Gill (PRESAT-CPMG) pulse sequences, ensuring high-quality spectral data and effective suppression of macromolecule signals. Comprehensive spectral processing and metabolite assignment are described, with guidance on multivariate and univariate statistical analyses to identify metabolic changes and potential biomarkers. The framework emphasises methodological rigour and reproducibility, enabling accurate quantification and interpretation of metabolites relevant to disease mechanisms or therapeutic interventions. By providing a standardised approach, this protocol supports longitudinal and translational studies, bridging findings from rodent models to clinical applications and advancing the reliability of metabolomics-based biomarker discovery in preclinical research. Full article

Bitumen, a vital component in road pavement construction, exhibits complex chemo-mechanical properties that necessitate thorough characterization for enhanced understanding and potential modifications. Nuclear Magnetic Resonance (NMR) spectroscopy emerges as a valuable technique for probing the structural and compositional features of bitumen. This review presents an in-depth exploration of the role of NMR spectroscopy in bitumen characterization, highlighting its diverse applications in determining bitumen content, group composition, molecular dynamics, and interaction with additives. Various NMR techniques, including free induction decay (FID), Carr–Purcell–Meilboom–Gill (CPMG), and Pulsed Field Gradient Stimulated Echo (PFGSE), are discussed in the context of their utility in bitumen analysis. Case studies, challenges, and limitations associated with NMR-based bitumen characterization are critically evaluated, offering insights into potential future research directions. Overall, this review provides a comprehensive overview of the current state-of-the-art in NMR-based bitumen characterization and identifies avenues for further advancement in the field. Full article

Advanced ¹H Nuclear Magnetic Resonance (NMR) relaxometry and diffusometry methods and VIS-nearIR spectroscopy combined with pH, electrical conductivity (EC) and totally dissolved solids (TDSSs) measurements were used to assess the properties of wastewater collected from a chicken slaughterhouse in each step of the treatment process (wastewater before treatment, biologically treated wastewater, chemically treated wastewater and discharged wastewater) and from sludge. The ¹H NMR Carr–Purcell–Meiboom–Gill (CPMG) and Pulsed-Gradient-Stimulated-Echo (PGSE) decay curves recorded for all samples of wastewater were analyzed by inverse Laplace transform (ILT) to obtain the distributions of transverse relaxation times T₂ and diffusion coefficient D. The VIS-nearIR total absorbance, T₂-values, D-values, pH, EC and TDSS parameters were used for statistical analysis in principal component (PCA). The ¹H T₂-distributions measured for the slaughterhouse wastewater lie in two main regions reflecting the number of dissolved solids or the distribution of undissolved solids. The PCA analysis successfully differentiates between polluted and less polluted wastewaters and sludge. The wastewater treatment applied by the slaughterhouse is efficient. The recommended methods for wastewater monitoring are the NMR T₂- and D-distributions and EC, TDSSs and NMR-D diffusion coefficient. Finally, Machine Learning algorithms are used to provide prediction maps of wastewater treatment stage. Full article

For the first time, High-Resolution Magic Angle Nuclear Magnetic Resonance spectroscopy (NMR-HRMAS) was applied to directly identify specific metabolites from a Spanish raw ewe’s milk and enzymatic coagulation pressed-curd cheese (Protected Geographical Indication: Castellano) manufactured by two procedures (traditional/artisanal vs. industrial) and including the ewe’s raw milk. The NMR parameters were optimized to study the complex matrixes of this type of cheese. In addition, conventional overcrowded ¹H-NMR-HRMAS spectra were selectively simplified by a Carr–Purcell–Meiboom–Gill (CPMG) sequence or a stimulated echo pulse sequence by bipolar gradients (DIFF), thus modulating spin–spin relaxation times and diffusion of molecular components, respectively. ¹H-NMR-HRMAS spectroscopy displayed important information about cheese metabolites, which can be associated with different manufacturing processes (industrial vs. traditional) and ripening times (from 2 to 90 days). These results support that this spectroscopy is a useful technique to monitor the ripening process, from raw milk to commercial ripened cheese, using a minimum intact sample, implying the absence of time-consuming sample pretreatments. Full article

With the aim to develop novel scaffolds for the sustained release of drugs, we initially developed an easy approach for the synthesis of α,ω-homobifunctional mercaptoacyl poly(alkyl oxide)s. This was based on the esterification of the terminal hydroxyl groups of poly(alkyl oxide)s with suitably S-4-methoxytrityl (Mmt)-protected mercapto acids, followed by the removal of the acid labile S-Mmt group. This method allowed for the efficient synthesis of the title compounds in high yield and purity, which were further used in the development of a thioether cross-linked liposome scaffold, by thia–Michael reaction of the terminal thiol groups with pre-formed nano-sized liposomes bearing maleimide groups on their surface. The reaction process was followed by ¹H-NMR, using a Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion NMR experiment (¹H-NMR CPMG), which allowed for real-time monitoring and optimization of the reaction process. The thioether cross-linked liposomal scaffold that was synthesized was proven to preserve the nano-sized characteristics of the initial liposomes and allowed for the sustained release of calcein (which was used as a hydrophilic dye and a hydrophilic drug model), providing evidence for the efficient synthesis of a novel drug release scaffold consisting of nanoliposome building blocks. Full article

In this study, an optimized unilateral magnetic resonance sensor with a three-magnet array is presented for assessing the aging of composite insulators in power grids. The sensor’s optimization involved enhancing the static magnetic field strength and the homogeneity of the RF field while maintaining a constant gradient in the direction of the vertical sensor surface and maximizing homogeneity in the horizontal direction. The center layer of the target area was positioned 4 mm from the coil’s upper surface, resulting in a magnetic field strength of 139.74 mT at the center point of the area, with a gradient of 2.318 T/m and a corresponding hydrogen atomic nuclear magnetic resonance frequency of 5.95 MHz. The magnetic field uniformity over a 10 mm × 10 mm range on the plane was 0.75%. The sensor measured 120 mm × 130.5 mm × 76 mm and weighed 7.5 kg. Employing the optimized sensor, magnetic resonance assessment experiments were conducted on composite insulator samples utilizing the CPMG (Carr–Purcell–Meiboom–Gill) pulse sequence. The T₂ distribution provided visualizations of the T₂ decay in insulator samples with different degrees of aging. Full article

‘Tonda Gentile Romana’ and ‘Tonda di Giffoni’ (Corylus avellana L.) are two Italian hazelnut cultivars, recognized under the quality labels “Protected Designation of Origin” (PDO) and “Protected Geographical Indication” (PGI), respectively. Hazelnut seeds are characterized by a complex microstructure and the presence of different physical compartments. This peculiarity has been studied and evidenced by Time Domain (TD) Nuclear Magnetic Resonance (NMR) experiments. This technique allowed the assessment of the presence of different diffusion compartments, or domains, by evaluating the distribution of the spin–spin relaxation time (T₂).The aim of this research was to develop a method based on ¹H NMR relaxometry to study the mobility in fresh hazelnut seeds (‘Tonda di Giffoni’ and ‘Tonda Gentile Romana’), in order to determine differences in seed structure and matrix mobility between the two cultivars. TD-NMR measurements were performed from 8 to 55 °C in order to mimic post-harvest processing as well the microscopic textural properties of hazelnut. The Carr–Purcell–Meiboom–Gill (CPMG) experiments showed five components for ‘Tonda Gentile Romana’ and four components for ‘Tonda di Giffoni’ relaxation times. The two slowest components of relaxation (T_2,a about 30–40% of the NMR signal, and T_2,b about 50% of the NMR signal) were attributed to the protons of the lipid molecules organized in the organelles (oleosomes), both for the ‘Tonda Gentile Romana’ and for the ‘Tonda di Giffoni’ samples. The component of relaxation T_2,c was assigned to cytoplasmic water molecules, and showed a T₂ value dominated by diffusive exchange with a reduced value compared to that of pure water at the same temperature. This can be attributed to the water molecules affected by the relaxation effect of the cell walls. The experiments carried out as a function of temperature showed, for ‘Tonda Gentile Romana’, an unexpected trend between 30 and 45 °C, indicating a phase transition in its oil component. This study provides information that could be used to strengthen the specifications underlying the definitions of “Protected Designation of Origin” (PDO) and “Protected Geographical Indication” (PGI). Full article

We present an experimental study of the coherence properties of a single heavy-hole spin qubit formed in one quantum dot of a gated GaAs/AlGaAs double quantum dot device. We use a modified spin-readout latching technique in which the second quantum dot serves both as an auxiliary element for a fast spin-dependent readout within a 200 ns time window and as a register for storing the spin-state information. To manipulate the single-spin qubit, we apply sequences of microwave bursts of various amplitudes and durations to make Rabi, Ramsey, Hahn-echo, and CPMG measurements. As a result of the qubit manipulation protocols combined with the latching spin readout, we determine and discuss the achieved qubit coherence times: $T_1$, $T_{Rabi}$, $T_2^{*}$, and $T_2^{CPMG}$ vs. microwave excitation amplitude, detuning, and additional relevant parameters. Full article

A novel cylinder permanent magnet governor (CPMG) with Halbach segmentation is proposed in this paper. In order to improve the transmission performance of the CPMG, different permanent magnet (PM) arrangement methods are adopted. To achieve a fair comparison result, all the PMs are of the same size. The main magnetic fluxes are considered to obtain a comprehensive equivalent magnetic circuit model of the CPMG with Halbach array and analytical output torque that is calculated. The analytical method of transmitted torque for CPMG is then presented. Additionally, the effect of the average output torque of CPMG under parameters of the thickness of the copper rings, the slip rate and the effective coupling of the copper rings are investigated. Finally, the prototype platform is ready for testing on the field. The results were consistent with the results of the simulation, and the error was kept within the range of 5%. This research can provide a theoretical and practical reference for the optimal design of the transmission characteristic of CPMG. Full article

Primary Sjögren’s Syndrome (pSS) is a multi-system autoimmune disease that involves the exocrine glands. Lymphocytes infiltrate the gland tissue, leading to anatomical modification and hypofunction. Even if the prognosis of pSS is favorable, quality of life is typically reduced due to the diverse manifestations of the disease. The aim of this study is to compare the salivary metabolomes of pSS with healthy controls (HCs). Seven cases were selected from a cohort of pSS patients, and six age- and sex-matched HCs were recruited from a cohort of volunteers. Whole unstimulated saliva was collected for NMR analysis. Our metabolomic analysis focused on 360 ms total echo 1D ¹H NMR CPMG spectra. Metabolites detected with CPMG NMR spectra were assigned through 2D NMR spectra (COSY, TOCSY, and HSQC). About 50 metabolites were detected and assigned. Unsupervised exploratory PCA returned partial clustering, and PLS-DA improved the separation between pSS and HCs, highlighting a pool of metabolites distinctly describing each group. Despite the limited number of samples, the presented preliminary data are promising. PLS-DA indicated well-defined group separation, suggesting that the application of ¹H-NMR metabolomics is suitable for the study of pSS. Full article