Acquiring pulmonary circulation parameters as a potential marker of cardiopulmonary function is not new. Methods to obtain these parameters have been developed over time, with the latest being first-pass perfusion sequences in cardiovascular magnetic resonance (CMR). Even though more data on these parameters has been recently published, different nomenclature and acquisition methods are used across studies; some works even reported conflicting data. The most commonly used circulation parameters obtained using CMR include pulmonary transit time (PTT) and pulmonary transit beats (PTB). PTT is the time needed for a contrast agent (typically gadolinium-based) to circulate from the right ventricle (RV) to the left ventricle (LV). PTB is the number of cardiac cycles the process takes. Some authors also include corrected heart rate (HR) versions along with standard PTT. Besides other methods, CMR offers an option to assess stress circulation parameters, but data are minimal. This review aims to summarize the up-to-date findings and provide an overview of the latest progress on this promising, dynamically evolving topic.

• MeSH
• kontrastní látky MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie * metody   MeSH
• plicní oběh fyziologie   MeSH
• prediktivní hodnota testů MeSH
• srdce * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• kontrastní látky MeSH

PURPOSE: To understand how macromolecular content varies in the human brain with age in a large cohort of healthy subjects. METHODS: In-vivo 1H-MR spectra were acquired using ultra-short TE STEAM at 7T in the posterior cingulate cortex. Macromolecular content was studied in 147 datasets from a cohort ranging in age from 19 to 89 y. Three fitting approaches were used to evaluate the macromolecular content: (1) a macromolecular resonances model developed for this study; (2) LCModel-simulated macromolecules; and (3) a combination of measured and LCModel-simulated macromolecules. The effect of age on the macromolecular content was investigated by considering age both as a continuous variable (i.e., linear regressions) and as a categorical variable (i.e., multiple comparisons among sub-groups obtained by stratifying data according to age by decade). RESULTS: While weak age-related effects were observed for macromolecular peaks at ˜0.9 (MM09), ˜1.2 (MM12), and ˜1.4 (MM14) ppm, moderate to strong effects were observed for peaks at ˜1.7 (MM17), and ˜2.0 (MM20) ppm. Significantly higher MM17 and MM20 content started from 30 to 40 y of age, while for MM09, MM12, and MM14, significantly higher content started from 60 to 70 y of age. CONCLUSIONS: Our findings provide insights into age-related differences in macromolecular contents and strengthen the necessity of using age-matched measured macromolecules during quantification.

• Klíčová slova
• LCModel, MRS, aging, macromolecules, ultra‐high field,
• MeSH
• cingulární gyrus diagnostické zobrazování   chemie   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• magnetická rezonanční tomografie metody   MeSH
• makromolekulární látky * chemie   MeSH
• mladý dospělý MeSH
• mozek diagnostické zobrazování   metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stárnutí * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• makromolekulární látky * MeSH

In this study, we investigated the potential of long-range fluorine-carbon J-coupling for determining the structures of deoxyfluorinated disaccharides. Three disaccharides, previously synthesized as potential galectin inhibitors, exhibited through-space fluorine-carbon J-couplings. In our independent conformational analysis of these disaccharide derivatives, we employed a combination of density functional theory (DFT) calculations and nuclear magnetic resonance (NMR) experiments. By comparing the calculated nuclear shieldings with the experimental carbon chemical shifts, we were able to identify the most probable conformers for each compound. A model comprising fluoromethane and methane molecules was used to study the relationship between molecular arrangements and intermolecular through-space J-coupling. Our study demonstrates the important effect of internuclear distance and molecular orientation on the magnitude of fluorine-carbon coupling. The experimental values for the fluorine-carbon through-space couplings (TSCs) of the disaccharides corresponded with values calculated for the most probable conformers identified by the conformational analysis. These results unlock the broader application of fluorine-carbon TSCs as powerful tools for conformational analysis of flexible molecules, offering valuable insights for future structural investigations.

• Klíčová slova
• Conformation, DFT calculations, Fluorine, NMR spectroscopy, Saccharides,
• MeSH
• disacharidy * chemie   MeSH
• fluor * chemie   MeSH
• konformace sacharidů MeSH
• magnetická rezonanční spektroskopie * MeSH
• molekulární konformace MeSH
• teorie funkcionálu hustoty * MeSH
• uhlík chemie   MeSH
• Publikační typ
• časopisecké články MeSH

HYPOTHESIS: The development of bimodal imaging probes represents a hot topic of current research. Herein, we deal with developing an innovative bimodal contrast agent enabling fluorescence imaging (FI)/magnetic resonance imaging (MRI) and, simultaneously, consisting of biocompatible nanostructures. Optimized synthesis of advanced protein-embedded bimetallic (APEBM) nanocomposite containing luminescent gold nanoclusters (AuNC) and superparamagnetic iron oxide nanoparticles (SPION), suitable for in vivo dual-modal FI/MR imaging is reported. EXPERIMENTS: The APEBM nanocomposite was prepared by a specific sequential one-pot green synthetic approach that is optimized to increase metals (Au, Fe) content and, consequently, the imaging ability of the resulting nanostructures. The protein matrix, represented by serum albumin, was intentionally chosen, and used since it creates an efficient protein corona for both types of optically/magnetically-susceptible nanostructures (AuNC, SPION) and ensures biocompatibility of the resulting APEBM nanocomposite although it contains elevated metal concentrations (approx. 1 mg·mL-1 of Au, around 0.3 mg·mL-1 of Fe). In vitro and in vivo imaging was performed. FINDINGS: Successful in vivo FI and MRI recorded in healthy mice corroborated the applicability of the APEBM nanocomposite and, simultaneously, served as a proof of concept concerning the potential future exploitation of this new FI/MRI bimodal contrast agent in preclinical and clinical practice.

• Klíčová slova
• Bioimaging, Contrast agent, Fluorescent imaging, Inorganic-organic nanocomposite, Magnetic resonance imaging, Magneto-luminescent nanocomposite,
• MeSH
• kontrastní látky * chemie   MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie metody   MeSH
• myši MeSH
• nanokompozity * chemie   MeSH
• optické zobrazování MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kontrastní látky * MeSH

β-Lactamases (EC 3.5.2.6) confer resistance against β-lactam group-containing antibiotics in bacteria and higher eukaryotes, including humans. Pathogenic bacterial resistance against β-lactam antibiotics is a primary concern for potential therapeutic developments and drug targets. Here, we report putative β-lactamase activity, sulbactam binding (a β-lactam analogue) in the low μM affinity range, and site-specific interaction studies of a 14 kDa UV- and dark-inducible protein (abbreviated as UVI31+, a BolA homologue) from Chlamydomonas reinhartii. Intriguingly, the solution NMR structure of UVI31 + bears no resemblance to other known β-lactamases; however, the sulbactam binding is found at two sites rich in positively charged residues, mainly at the L2 loop regions and the N-terminus. Using NMR spectroscopy, ITC and MD simulations, we map the ligand binding sites in UVI31 + providing atomic-level insights into its β-lactamase activity. Current study is the first report on β-lactamase activity of UVI31+, a BolA analogue, from C. reinhartii. Furthermore, our mutation studies reveal that the active site serine-55 is crucial for β-lactamase activity.

• Klíčová slova
• ITC, MD, NMR, S55A, Sulbactam, UVI31+, β-lactam antibiotics, β-lactamases,
• MeSH
• beta-laktamasy * chemie   metabolismus   MeSH
• Chlamydomonas reinhardtii * enzymologie   MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• nukleární magnetická rezonance biomolekulární metody   MeSH
• rostlinné proteiny chemie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• simulace molekulární dynamiky MeSH
• sulbaktam chemie   farmakologie   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Publikační typ
• časopisecké články MeSH

Metabolomics has become an important tool in elucidating the complex relationship between a plant genotype and phenotype. For over 20 years, nuclear magnetic resonance (NMR) spectroscopy has been known for its robustness, quantitative capabilities, simplicity, and cost-efficiency. 1H NMR is the method of choice for analyzing a broad range of relatively abundant metabolites, which can be used for both capturing the plant chemical profile at one point in time and understanding the pathways that underpin plant defense. This systematic Review explores how 1H NMR-based plant metabolomics has contributed to understanding the role of various compounds in plant responses to biotic stress, focusing on both primary and secondary metabolites. It clarifies the challenges and advantages of using 1H NMR in plant metabolomics, interprets common trends observed, and suggests guidelines for method development and establishing standard procedures.

• Klíčová slova
• chemical responses, extraction protocol, host plant resistance, integrative omics, plant defense, secondary metabolites,
• MeSH
• fyziologický stres MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• magnetická rezonanční tomografie * MeSH
• metabolomika * metody   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• rostliny MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• systematický přehled MeSH

PURPOSE: Water removal is one of the computational bottlenecks in the processing of high-resolution MRSI data. The purpose of this work is to propose an approach to reduce the computing time required for water removal in large MRS data. METHODS: In this work, we describe a singular value decomposition-based approach that uses the partial position-time separability and the time-domain linear predictability of MRSI data to reduce the computational time required for water removal. Our approach arranges MRS signals in a Casorati matrix form, applies low-rank approximations utilizing singular value decomposition, removes residual water from the most prominent left-singular vectors, and finally reconstructs the water-free matrix using the processed left-singular vectors. RESULTS: We have demonstrated the effectiveness of our proposed algorithm for water removal using both simulated and in vivo data. The proposed algorithm encompasses a pip-installable tool ( https://pypi.org/project/CSVD/), available on GitHub ( https://github.com/amirshamaei/CSVD), empowering researchers to use it in future studies. Additionally, to further promote transparency and reproducibility, we provide comprehensive code for result replication. CONCLUSIONS: The findings of this study suggest that the proposed method is a promising alternative to existing water removal methods due to its low processing time and good performance in removing water signals.

• Klíčová slova
• MR spectroscopic imaging, functional MRS, low-rank approximations, water removal, water suppression,
• MeSH
• algoritmy MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie * metody   MeSH
• reprodukovatelnost výsledků MeSH
• voda * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• voda * MeSH

The development of NMR crystallography methods requires a reliable database of chemical shifts measured for systems with known crystal structure. We measured and assigned carbon and hydrogen chemical shifts of twenty solid natural amino acids of known polymorphic structure, meticulously determined using powder X-ray diffraction. We then correlated the experimental data with DFT-calculated isotropic shieldings. The small size of the unit cell of most amino acids allowed for advanced computations using various families of DFT functionals, including generalized gradient approximation (GGA), meta-GGA and hybrid DFT functionals. We tested several combinations of functionals for geometry optimizations and NMR calculations. For carbon shieldings, the widely used GGA functional PBE performed very well, although an improvement could be achieved by adding shielding corrections calculated for isolated molecules using a hybrid functional. For hydrogen nuclei, we observed the best performance for NMR calculations carried out with structures optimized at the hybrid DFT level. The high fidelity of the calculations made it possible to assign additional signals that could not be assigned based on experiments alone, for example signals of two non-equivalent molecules in the unit cell of some of the amino acids.

• Klíčová slova
• Amino acids, DFT calculations, Disorder, Polymorphism, Solid-state NMR spectroscopy,
• MeSH
• aminokyseliny * MeSH
• krystalografie MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• uhlík * MeSH
• vodík MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny * MeSH
• uhlík * MeSH
• vodík MeSH

Cyclic dinucleotides (CDNs) are important second messengers in bacteria and eukaryotes. Detailed characterization of their physicochemical properties is a prerequisite for understanding their biological functions. Herein, we examine acid-base and electromigration properties of selected CDNs employing capillary electrophoresis (CE), density functional theory (DFT), and nuclear magnetic resonance (NMR) spectroscopy to provide benchmark pKa values, as well as to unambiguously determine the protonation sites. Acidity constants (pKa) of the NH+ moieties of adenine and guanine bases and actual and limiting ionic mobilities of CDNs were determined by nonlinear regression analysis of the pH dependence of their effective electrophoretic mobilities measured by CE in aqueous background electrolytes in a wide pH range (0.98-11.48), at constant temperature (25°C), and constant ionic strength (25 mM). The thermodynamic pKa values were found to be in the range 3.31-4.56 for adenine and 2.28-3.61 for guanine bases, whereas the pKa of enol group of guanine base was in the range 10.21-10.40. Except for systematic shifts of ∼2 pKa, the pKa values calculated by the DFT-D3//COSMO-RS composite protocol that included large-scale conformational sampling and "cross-morphing" were in a relatively good agreement with the pKas determined by CE and predict N1 atom of adenine and N7 atom of guanine as the protonation sites. The protonation of the N1 atom of adenine and N7 atom of guanine in acidic background electrolytes (BGEs) and the dissociation of the enol group of guanine in alkaline BGEs was confirmed also by NMR spectroscopy.

• Klíčová slova
• DFT calculations, NMR spectroscopy, acidity constant, capillary electrophoresis, cyclic dinucleotides,
• MeSH
• dinukleosidfosfáty chemie   MeSH
• elektroforéza kapilární * metody   MeSH
• koncentrace vodíkových iontů MeSH
• magnetická rezonanční spektroskopie * metody   MeSH
• protony * MeSH
• teorie funkcionálu hustoty MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dinukleosidfosfáty MeSH
• protony * MeSH

Na-V-P-Nb-based materials have gained substantial recognition as cathode materials in high-rate sodium-ion batteries due to their unique properties and compositions, comprising both alkali and transition metal ions, which allow them to exhibit a mixed ionic-polaronic conduction mechanism. In this study, the impact of introducing two transition metal oxides, V2O5 and Nb2O5, on the thermal, (micro)structural, and electrical properties of the 35Na2O-25V2O5-(40 - x)P2O5 - xNb2O5 system is examined. The starting glass shows the highest values of DC conductivity, σDC, reaching 1.45 × 10-8 Ω-1 cm-1 at 303 K, along with a glass transition temperature, Tg, of 371 °C. The incorporation of Nb2O5 influences both σDC and Tg, resulting in non-linear trends, with the lowest values observed for the glass with x = 20 mol%. Electron paramagnetic resonance measurements and vibrational spectroscopy results suggest that the observed non-monotonic trend in σDC arises from a diminishing contribution of polaronic conductivity due to the decrease in the relative number of V4+ ions and the introduction of Nb2O5, which disrupts the predominantly mixed vanadate-phosphate network within the starting glasses, consequently impeding polaronic transport. The mechanism of electrical transport is investigated using the model-free Summerfield scaling procedure, revealing the presence of mixed ionic-polaronic conductivity in glasses where x < 10 mol%, whereas for x ≥ 10 mol%, the ionic conductivity mechanism becomes prominent. To assess the impact of the V2O5 content on the electrical transport mechanism, a comparative analysis of two analogue series with varying V2O5 content (10 and 25 mol%) is conducted to evaluate the extent of its polaronic contribution.

• Klíčová slova
• (micro)structure–property relationship, EPR, PXRD, SEM-EDS, electrical properties, impedance spectroscopy, phosphate glasses, phosphate glass–ceramics, vibrational spectroscopy,
• MeSH
• elektronová paramagnetická rezonance MeSH
• fosfáty * chemie   MeSH
• ionty MeSH
• keramika chemie   MeSH
• niob * MeSH
• sklo chemie   MeSH
• sodík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfáty * MeSH
• ionty MeSH
• niob * MeSH
• sodík MeSH
• sodium phosphate MeSH Prohlížeč
• sodium polymetaphosphate MeSH Prohlížeč