Magnetic Resonance Spectroscopy Measurements Research Articles

Highly bioactive novel aryl-, benzyl-, and piperazine-selenoureas: synthesis, structural characterization and in vitro biological evaluation

Selenoureas are widespread as useful elements for constructing important species and biologically active molecules. Finding an efficient and straightforward method to prepare this motif and biologically screen derivatives thereof is crucial. Herein, we demonstrate the effectiveness of using ethanol as a solvent in the preparation of various substituted aryl-, benzyl-, and piperazine-selenoureas from isoselenocyanates and amines. The synthetic method includes mild reaction conditions, large substrate scope, and good isolated yields. Biological evaluation of the prepared products on MDA-MB-231 and MCF-7 cancer cell lines revealed several remarkably active compounds (IC50 < 10 μΜ) with the best one exhibiting IC50 values of 1.8 μΜ and 1.2 μΜ observed against the challenging former triple-negative breast cancer cell line and the latter one, respectively. The chemical structures of all new compounds were fully characterized by multinuclear nuclear magnetic resonance (NMR) spectroscopy and high accuracy mass measurements.

Tailoring the Time-Averaged Structure for Polarization-Sensitive Chiral Perovskites.

Chiral perovskites have emerged as promising candidates for polarization-sensing materials. Despite their excellent chiroptical properties, the nature of their multiple-quantum-well structures is a critical hurdle for polarization-based and spintronic applications. Furthermore, as the origin of chiroptical activity in chiral perovskites is still illusive, the strategy for simultaneously enhancing the chiroptical activity and charge transport has not yet been reported. Here, we demonstrated that incorporating a Lewis base into the lattice can effectively tune the chiroptical response and electrical properties of chiral perovskites. Through solid-state nuclear magnetic resonance spectroscopic measurements and theoretical calculations, it was demonstrated that the material property manipulation resulted from the change in the time-averaged structure induced by the Lewis base. Finally, as a preliminary proof of concept, a vertical-type circularly polarized light photodetector based on chiral perovskites was developed, exhibiting an outstanding performance with a distinguishability of 0.27 and a responsivity of 0.43 A W-1.

Assessing the Experimental Hydrogen Bonding Energy of the Cyclic Water Dimer Transition State with a Cyclooctatetraene-Based Molecular Balance.

We have conducted an experimental and computational study of cyclooctatetraene-1,4/1,6-dimethanol (1,4 and 1,6) as a molecular balance with the goal in mind to determine the otherwise inaccessible hydrogen bonding energy (HBE) of the cyclic water dimer, which constitutes a transition state. The 1,4/1,6 folding equilibrium is governed by an intramolecular hydrogen bond in the folded 1,6-isomer, in which the OH groups adopt a cyclic planar geometry, akin to the structure of the cyclic water dimer transition state. We characterized hydrogen bonding in 1,6 and reference complexes utilizing SAPT2 + (3)δMP2/aug-cc-pVTZ and selected quantum theory of atoms in molecule descriptors at M06-2XD3(0)/ma-def2-TZVPP. Additionally, we computed HBEs at the DLPNO-CCSD(T)/aug-cc-pVQZ level of theory. We find that hydrogen bonding in 1,6 is very similar to the interaction in the Ci symmetric cyclic water dimer TS, both in magnitude and character. We experimentally determined the Gibbs free energy of the folding process (ΔGeq) in a variety of organic solvents via nuclear magnetic resonance spectroscopy measurements at room temperature. By combining experimentally obtained ΔGeq values with corrections derived from accurate computational methods, we provide estimates for the HBE of cyclic water dimers and the cyclic water dimer TS, as the most stable cyclic water dimer.

Determine the coordination of Al and Si of Fe-rich fly ash: The challenge in NMR and how we probe its heterogeneity using X-ray spectromicroscopy

Scanning transmission X-ray microscopy (STXM) coupled with ptychographic imaging at Al and Si K-edge is a new probe to the microscale chemistry of heterogenous materials. Here, the combined techniques are applied to study local coordination environment of Fe-rich fly ash (FA). Ptychographic imaging at Al K- and Si K-edge highlights the fine Al- and Si-rich morphological features, respectively, at 6 nm pixel resolution. STXM visualizes the inter- and intra-particle variations in the silicate polymerization degree and two types of Al coordination environment in FA. The Si K-edge of SiO4 connected with four-fold coordinated Al is higher than SiO4 sharing oxygen with six-fold coordinated Al. The result is consistent with bulk nuclear magnetic resonance spectroscopy measurement of the Fe-rich sample which, however, is sensitive to paramagnetic Fe and time-consuming. We demonstrate that the combined method has great potential in the studies of chemically heterogenous aluminosilicates.

Imaging Glioblastoma Response to Radiotherapy Using 2H Magnetic Resonance Spectroscopy Measurements of Fumarate Metabolism.

2H magnetic resonance imaging of labeled fumarate metabolism can detect early evidence of tumor cell death following chemoradiation, meeting a clinical need to reliably detect treatment response in glioblastoma.

Putamen Structure and Function in Familial Risk for Depression: A Multimodal Imaging Study

BackgroundThe putamen has been implicated in depressive disorders, but how its structure and function increase depression risk is not clearly understood. Here, we examined how putamen volume, neuronal density, and mood-modulated functional activity relate to family history and prospective course of depression. MethodsThe study includes 115 second- and third-generation offspring at high or low risk for depression based on the presence or absence of major depressive disorder in the first generation. Offspring were followed longitudinally using semistructured clinical interviews blinded to their familial risk; putamen structure, neuronal integrity, and functional activation were indexed by structural magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy (N-acetylaspartate/creatine ratio), and functional MRI activity modulated by valence and arousal components of a mood induction task, respectively. ResultsAfter adjusting for covariates, the high-risk individuals had lower putamen volume (standardized betas, β-left = −0.17, β-right = −0.15, ps = .002), N-acetylaspartate/creatine ratio (β-left= −0.40, β-right= −0.37, ps < .0001), and activation modulated by valence (β-left = −0.22, β-right = −0.27, ps < .05) than low-risk individuals. Volume differences were greater at younger ages, and N-acetylaspartate/creatine ratio differences were greater at older ages. Lower putamen volume also predicted major depressive disorder episodes up to 8 years after the scan (β-left = −0.72, p = .013; β-right = −0.83, p = .037). Magnetic resonance spectroscopy and task functional MRI measures were modestly correlated (0.27 ≤ r ≤ 0.33). ConclusionsFindings demonstrate abnormalities in putamen structure and function in individuals at high risk for major depressive disorder. Future studies should focus on this region as a potential biomarker for depressive illness, noting meanwhile that differences attributable to family history may peak at different ages based on which MRI modality is being used to assay them.

Clustering of facies in tight carbonates using machine learning

Machine learning clustering methods offer the potential for recognition and separation of facies based on core or well-log data. This is a particular problem for carbonate rocks because diagenesis produces a wide range of rock microstructures and transport properties. In this work we use a large database of high quality poroperm, electrical, mercury injection capillary pressure and nuclear magnetic resonance spectroscopy measurements (307 core samples), representing 5 stratigraphically defined facies, as well as well log data to examine facies-recognition abilities using 8 different machine learning clustering approaches and a redundancy of 10 to ensure statistically valid results, resulting in a total of over 990 clustering runs. For a 3 cluster problem, we find that the Expectation Maximisation (92.57% success) and two types of Kmeans approaches (89.60% and 91.09%) provide the best methods. Further testing using the best of these shows that the quality of the input parameter (attribute) matters more than the number of attributes used, with the power of attributes in decreasing order being porosity, cementation exponent, permeability, pore throat diameter and free fluid index, implying that some attributes can degrade clustering performance. Further tests show that there should be at least as many attributes as clusters, in which case the machine learning can be left to choose the final number of clusters, providing the best performance in this work (69.35% success for a five cluster problem), otherwise it is best to constrain the cluster number by supervision. Application of the results from the previous testing to a mixed carbonate tight carbonate well from the Butmah formation shows satisfactory determination of 4 petrofacies by clustering (up to 91.65%) when compared to petrofacies determined manually. However, the greater challenge of clustering 9 reservoir quality classes defined using a ternary petrofacies approach did not provide a successful result (<38% success rate).

A Sobering Examination of the Feasibility of Aqueous Aluminum Batteries

Aqueous aluminum (Al) batteries are posited to be a cheap and energy dense alternative to conventional Li-ion chemistries, but an aqueous electrolyte mediating trivalent aluminum cations (Al3+) warrants greater scrutiny. This study provides a rigorous examination of aqueous Al electrolytes, with the first compelling evidence for a dynamic octahedral solvation structure around the Al3+, without Al-OTf contact ion pairs, even at high concentrations. This solvation behavior and the concomitant, transient electrostatic hydrolysis of Al-OH2 ligands contrasts strongly with previously reported water-in-salt electrolytes, and occurs due to the high charge density of the Lewis acidic Al3+. Nuclear magnetic resonance spectroscopy and other physicochemical measurements quantitatively reveal how species activity evolves with concentration and temperature. This new understanding exposes practical concerns related to the corrosiveness of the acidic aqueous solutions, the degree of hydration of aluminum trifluoromethanesulfonate (Al(OTf)3) salt, and the grossly insufficient reductive stability of the proposed electrolytes (>1 V between HER onset and Al3+/Al). Collectively, these factors constitute multiple fundamental barriers to the feasibility of rechargeable aqueous Al batteries.Table of Contents: We assess the challenges associated with aqueous aluminum electrolyte by investigating the solvation structure of the Al3+ Lewis acid in Al(OTf)3-H2O solutions. The deprotonation of water ligands in the first solvation sheath leads to early onset of hydrogen evolution in super-concentrated aqueous aluminum electrolyte. Figure 1

Continuous Ingestion of Lacticaseibacillus rhamnosus JB-1 during Chronic Stress Ensures Neurometabolic and Behavioural Stability in Rats.

The intestinal microbiome composition and dietary supplementation with psychobiotics can result in neurochemical alterations in the brain, which are possible due to the presence of the brain–gut–microbiome axis. In the present study, magnetic resonance spectroscopy (MRS) and behavioural testing were used to evaluate whether treatment with Lacticaseibacillus rhamnosus JB-1 (JB-1) bacteria alters brain metabolites’ levels and behaviour during continuous exposure to chronic stress. Twenty Wistar rats were subjected to eight weeks of a chronic unpredictable mild stress protocol. Simultaneously, half of them were fed with JB-1 bacteria, and the second half was given a daily placebo. Animals were examined at three-time points: before starting the stress protocol and after five and eight weeks of stress onset. In the elevated plus maze behavioural test the placebo group displayed increased anxiety expressed by almost complete avoidance of exploration, while the JB-1 dietary supplementation mitigated anxiety which resulted in a longer exploration time. Hippocampal MRS measurements demonstrated a significant decrease in glutamine + glutathione concentration in the placebo group compared to the JB-1 bacteria-supplemented group after five weeks of stress. With the progression of stress, the decrease of glutamate, glutathione, taurine, and macromolecular concentrations were observed in the placebo group as compared to baseline. The level of brain metabolites in the JB-1-supplemented rats were stable throughout the experiment, with only the taurine level decreasing between weeks five and eight of stress. These data indicated that the JB-1 bacteria diet might stabilize levels of stress-related neurometabolites in rat brain and could prevent the development of anxiety/depressive-like behaviour.

Accumulation of Intramyocellular Acetylcarnitine is Associated with Glycolytic ATP Production In Vivo During Incremental Contractions in Human Skeletal Muscle

The interplay in vivo between muscle bioenergetics (ATP production) and intermediary metabolism in working skeletal muscle is not fully understood. During contractions, acetylcarnitine (AC) production may be an important modulator of energetic pathway and fuel selection for the support of ATP production. As contraction intensity and energetic demand increase, free carnitine in the mitochondria buffers excess acetyl‐CoA by converting it into AC and free CoA. This process enables greater flux of pyruvate into the mitochondria by lessening acetyl‐CoA’s product inhibition of pyruvate dehydrogenase. Further, as AC accumulates in the mitochondria, it will move into the cytosol, where by its conversion to malonyl‐CoA it can have the additional effect of inhibiting fatty acid translocation into the mitochondria. Here, a new method combining noninvasive magnetic resonance spectroscopic (MRS) measures of AC (by 1H MRS) with phosphorus MRS measures of ATP production was used to investigate the link between [AC] and energy production in vivo. Our primary aim was to test the novel hypothesis that AC accumulation during muscular work would be directly associated with nonoxidative (i.e., wherein the fate of pyruvate is lactate) glycolytic ATP production. Using a 3‐Tesla MR system with a dual‐tuned (1H/31P) surface coil, intracellular phosphorus metabolites and pH were measured in the vastus lateralis muscle of 8 males (mean 28.4 yr, range 25‐45) during 8 min of incremental isotonic contractions (0.5 Hz, 2‐min stages at 6, 9, 12, and 15% maximal torque). These metabolites and pH were then used to calculate ATP production (mM·s‐1) via oxidative phosphorylation, nonoxidative glycolysis, and the creatine kinase reaction (CK) throughout the contraction protocol. [AC] was measured in resting muscle pre‐ and post‐contractions. Spearman rank correlation coefficients (rs) were calculated to evaluate associations between post‐contraction [AC] and ATP production during the incremental protocol. On average, 13.1% (range 8.6 ‐ 17.3) of ATP production during the contraction protocol was from CK, 11.3% (0.4 ‐ 29.3) through glycolysis, and 75.6% (55.3 ‐ 90) by oxidative metabolism. [AC] increased &gt; 5‐fold, from 4.4 mM pre‐contractions (1.6‐11.6, n = 7) to 22.5 mM post (13.6 ‐ 33.8, n = 8; p = 0.004). Post‐contraction [AC] was positively correlated with absolute (mM·s‐1) and relative (% total) glycolytic ATP production (rs = 0.95, p = 0.001), supporting our primary hypothesis. Notably, post‐contraction [AC] was negatively correlated with relative (rs = ‐0.81 p = 0.02) but not absolute (rs = ‐0.14, p = 0.75) oxidative ATP production. Thus, cytosolic AC accumulated more when there was greater reliance on glycolysis and a relatively lower overall contribution from oxidative metabolism – a situation consistent with a buildup of acetyl‐CoA in the mitochondria. These results demonstrate, for the first time, the connection between energetic pathway selection and a key metabolic intermediate in working muscle in vivo. Intramyocellular AC may be a valuable tool for probing muscle energetics, substrate utilization, and metabolic flexibility in the future.

The role of MRS-assessed GABA in human behavioral performance.

Understanding the neurophysiological mechanisms that drive human behavior has been a long-standing focus of cognitive neuroscience. One well-known neuro-metabolite involved in the creation of optimal behavioral repertoires is GABA, the main inhibitory neurochemical in the human brain. Converging evidence from both animal and human studies indicates that individual variations in GABAergic function are associated with behavioral performance. In humans, one increasingly used in vivo approach to measuring GABA levels is through Magnetic Resonance Spectroscopy (MRS). However, the implications of MRS measures of GABA for behavior remain poorly understood. In this respect, it is yet to be determined how GABA levels within distinct task-related brain regions of interest account for differences in behavioral performance. This review summarizes findings from cross-sectional studies that determined baseline MRS-assessed GABA levels and examined their associations with performance on various behaviors representing the perceptual, motor and cognitive domains, with a particular focus on healthy participants across the lifespan. Overall, the results indicate that MRS-assessed GABA levels play a pivotal role in various domains of behavior. Even though some converging patterns emerge, it is challenging to draw comprehensive conclusions due to differences in behavioral task paradigms, targeted brain regions of interest, implemented MRS techniques and reference compounds used. Across all studies, the effects of GABA levels on behavioral performance point to generic and partially independent functions that refer to distinctiveness, interference suppression and cognitive flexibility. On one hand, higher baseline GABA levels may support the distinctiveness of neural representations during task performance and better coping with interference and suppression of preferred response tendencies. On the other hand, lower baseline GABA levels may support a reduction of inhibition, leading to higher cognitive flexibility. These effects are task-dependent and appear to be mediated by age. Nonetheless, additional studies using emerging advanced methods are required to further clarify the role of MRS-assessed GABA in behavioral performance.

Impact of O2 Availability on Convective and Diffusive O2 Transport and Skeletal Muscle Intracellular PO2 at VO2max

Cross‐sectional evidence suggests that maximal O2 uptake (VO2max) is the consequence of well‐matched O2 supply and demand in untrained skeletal muscle (symmorphosis) and in trained skeletal muscle is limited, not by mitochondrial O2 capacity, but, by convective and diffusive O2 transport (dysmorphosis). However, it is unknown if, longitudinally, aerobic exercise training transitions skeletal muscle VO2max from a sym‐ to a dys‐morphosis of O2 transport and utilization capacities. The purpose of this study was to test the hypothesis that, compared to normoxia, hyperoxia would increase skeletal muscle mean capillary PO2 (capPO2) and intracellular PO2 (iPO2) both pre‐ and post‐training, but would only increase VO2max post‐training. We tested this in 5 healthy sedentary males (mean±SD; age: 27±5 yrs, height: 175±6 cm, mass: 73±7 kg, cycle VO2max: 33±4 ml/kg/min) using the unique combination of human quadriceps single‐leg knee‐extensor exercise (KE), directly measured arterial and femoral PO2, thermodilution measured leg blood flow (LBF), and 1H nuclear magnetic resonance spectroscopy measurement of myoglobin (Mb) desaturation at 100% maximal work rate in randomized conditions of hypoxia, normoxia, and hyperoxia (12, 21, and 100 % O2, respectively). Mb desaturation was converted to iPO2 using an O2 half‐saturation pressure of 3.2 mmHg. All measurements were made pre‐ and post‐training, which consisted of eight weeks of KE (1 hour/visit, 3 visits/week). Pre‐training, increasing inspired O2 increased capPO2 (33.0±4.8, 41.4±4.1, and 49.6±8.7 mmHg, all p&lt;0.019), Mb desaturation decreased from hypoxia to normoxia (46±4 and 31±4 %, p=0.004), but not from normoxia to hyperoxia (29±14 %, p=0.79), iPO2 increased from hypoxia to normoxia (3.8±0.6 and 7.2±1.4 mmHg, p=0.009), but not from normoxia to hyperoxia (10.0±6.6 mmHg, p=0.375), and VO2max was not altered by inspired O2 (0.47±0.10, 0.52±0.13, and 0.54±.01 l/min, all p&gt;0.285). Post‐training, increasing inspired O2 increased capPO2 (32.8±2.6, 39.6±2.8, and 47.5±6.1 mmHg, all p&lt;0.010), did not decrease Mb desaturation (79±20, 53±11, and 53±8 %, all p&gt;0.050), iPO2 increased from hypoxia to normoxia (1.1±1.2 and 3.1±1.1 mmHg, p=0.019), but not from normoxia to hyperoxia (3.0±1.1 mmHg, p=0.954), and VO2max increased with greater inspired O2(0.59±0.11, 0.68±0.11, and 0.76±0.09 l/min, all p&lt;0.044). There was a pre‐ to post‐training difference within all three inspired O2 conditions for VO2max (all p&lt;0.010) and in hypoxia and normoxia for both Mb desaturation (both p&lt;0.020) and iPO2 (both p&lt;0.011). When untrained, the concomitant increase in capPO2 and iPO2, with no change in VO2max, from normoxia to hyperoxia infers a mitochondrial O2 capacity limited skeletal muscle VO2max. In trained skeletal muscle, the concomitant increase in capPO2 and VO2max, with minimal changes in iPO2, from normoxia to hyperoxia infers an O2 transport limited VO2max.

Relating the cortical visual contrast gain response to spectroscopy-measured excitatory and inhibitory metabolites in people who experience migraine.

ObjectiveThis study aimed to determine whether the visual response to flickering checkerboard patterns measured using electroencephalography (EEG) relate to excitatory or inhibitory metabolite levels measured using ultra-high (7Tesla/7T) magnetic resonance spectroscopy (MRS).BackgroundElectrophysiological studies have shown altered visual cortical response amplitudes and contrast gain responses to high contrast flickering patterns in people with migraine. These contrast response anomalies have been argued to represent an imbalance between cortical inhibition and excitation, however the specific mechanism has not been elucidated.MethodsMRS-measured metabolite levels were obtained from the occipital cortex of 18 participants with migraine and 18 non-headache controls. EEG contrast gain response functions were collected on separate days from a subset of 10 participants with migraine and 12 non-headache controls. Case-control outcome measures were statistically compared between groups both before and after checkboard exposure.ResultsNo significant difference in GABA and glutamate levels were found between groups nor checkerboard timepoint. Glucose levels were significantly reduced after checkerboard exposure in both participant groups. There was no metabolic signature in visual cortex in response to high-contrast flickering checkboards that distinguished those with migraine and without. There was also no correlation between MRS and EEG measurements in response to the flickering checkerboard.ConclusionOur findings suggest that the mechanisms driving contrast-flickering stimulus aversion are not simplistically reflected by gross changes in metabolic activity in the primary visual cortex.

Combination of permanent hydrosilylation and reversible Diels–Alder reactions for self-healing poly(dimethylsiloxane) materials with enhanced ageing properties

Poly (dimethylsiloxane)s (PDMS) are widely used in space applications thanks to their transparency, thermal and UV resistance, inter alia. The prolonged exposure of these materials to the geostationary environment leads to the apparition of cracks and changes in their optical properties, this being detrimental to their function. To enhance their lifespan, self-healing PDMS based on a dual network featuring both permanent and reversible units thanks to hydrosilylation and Diels–Alder reactions were designed. The tunable chemical composition of the networks was characterized by proton Nuclear Magnetic Resonance spectroscopy (1H NMR) and Fourier-transformed infrared-attenuated total reflection (FTIR-ATR) measurements. The thermal and mechanical behaviors of pristine and healed materials were mainly studied by differential scanning calorimetry, dynamic mechanical analysis, and tensiometry. Ageing under proton irradiations was also performed, simulating part of the radiations encountered in geostationary environment. Ultraviolet-visible-near infrared analyses were carried out to compare the materials optical properties both before and after irradiations. Finally, chemical degradation mechanisms were studied by FTIR-ATR analyses and discussed.

Phase separation in surfactant-containing amorphous solid dispersions: Orthogonal analytical methods to probe the effects of surfactants on morphology and phase composition

Amorphous–amorphous phase separation (AAPS) is an important phase transition process for amorphous solid dispersion (ASD) performance both in terms of drug release as well as physical and chemical stability during storage. Addition of surfactants to ASD systems can impact both of these processes. One possible mechanism through which surfactants affect ASD performance is via their impact on AAPS. Unfortunately, despite their increasing usage in ASD formulations, the effect of surfactant on AAPS is still poorly understood, and there are limited analytical techniques that provide microstructural and composition information about phase separated ASDs. In this study, the impact of four surfactants (sodium dodecyl sulfate, Tween 80, Span 20 and Span 85) on water-induced phase separation in ASDs formulated with ritonavir and polyvinylpyrrolidone/vinyl acetate (PVPVA) was investigated using a variety of orthogonal analytical methods. Transparent films of ASDs with different compositions were prepared by spin coating. Fluorescence confocal microscopy in combination with an in situ humidity chamber was used to monitor the kinetics and morphology of phase separation following exposure to high relative humidity. Optical photothermal IR analysis of phase separated films enabled characterization of domain composition and surfactant distribution. Liquid-liquid phase separation concentration, zeta potential and solution nuclear magnetic resonance spectroscopy measurements enabled interpretation of interaction with and partition of surfactants into the drug-rich phase. It was found that phase separation kinetics and morphology were notably changed by the surfactants. Further, the surfactants showed different affinities for the drug-rich versus the aqueous/polymer-rich phases. The employed analytical techniques were found to be complementary in providing insight into surfactant location in phase separated systems. This study highlights the complexity of phase separation, especially in the presence of surfactants, and provides a foundation to understand the impact of AAPS on ASD performance.

Structural transitions in TPGS micelles induced by trehalose as a model cryoprotectant

Cryoprotectants are included to protect colloidal dispersions from mechanical stress of ice crystals formed at sub-zero temperature. Trehalose (THL) remains a popular choice among sugar-based cryoprotectants. In the present study, we illustrate the effect of THL concentration (0.01–1 M) upon microstructural characteristics of nonionic micelles which were formulated with alpha tocopherol polyethylene glycol 1000 succinate (TPGS). The effect of THL incorporation in drug-loaded micelles was studied by using capsaicin (CAP), a hydrophobic alkaloid. Our interpretations are based on the results of cloud point, dynamic light scattering (DLS), small angle neutron scattering (SANS), nuclear magnetic resonance (NMR) and Fourier-transformed infrared (FTIR) spectroscopic measurements. Cloud point and spectral data reveal that the micelles underwent progressive dehydration at increasing THL concentration. Together with scattering data, it is discernible that THL molecules intercalated in the micelle corona and expelled water from the polar headgroups. In spite of this, micelle size did not change until 1 M THL. Freeze-thawed micelles also displayed identical size distribution. Structural transitions occurred upon solubilization of CAP; micelles changed from sphere to ellipsoids. We suggest that CAP molecules occupied the hydrophobic core and triggered the formation of ellipsoids which were retained in the presence of THL. These observations lead us to a conclusion that, by virtue of its selective action (removal of freezable water) in headgroup region, THL protects the morphology of micelles over a wide concentration range.

Synthesis of renewable soybean protein and acrylate copolymers via ATRP in ionic liquid

In this paper, acrylate and glycidyl methacrylate (GMA) were grafted onto the main chain of soy protein isolate (SPI) in 1-butyl-2,3-dimethylimidazole chloride ionic liquid ([BDMIM][Cl]), to prepare a renewable soy protein graft copolymer via atom transfer radical polymerization (ATRP). The effect of unfolding degree of soy protein structure on pretreated SPI was studied via Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance spectroscopy (1 H NMR), surface tension (ST) and contact angle (CA) measurements. The results of FT-IR, 1 H NMR and energy dispersive spectrometry (EDS) indicated the successful synthesis of 2-bromoisobutyryl-functionalized SPI.The analysis of FT-IR and 1H NMR spectra showed that the soybean protein graft copolymer was successfully synthesized. In addition, the grafting of acrylate onto soybean protein enhanced the hydrophobicity of the copolymer, and the static contact angle was above 90°. Differential scanning calorimetry (DSC) analysis revealed that the thermal stability of pretreated SPI was reduced. The new glass transition temperature in the copolymers also proved the successful synthesis of the copolymers. The tensile strength of the carbon fiber multifilament infiltrated with the copolymers was improved, indicating their potential application in the reinforcement of carbon fiber material.

Konjac glucomannan decreases metabolite release of a plant-based fishball analogue during in vitro digestion by affecting amino acid and carbohydrate metabolic pathways

Konjac glucomannan (KGM) provides a sense of fullness by delaying physiological processes related to food digestion, which helps weight management and cholesterol maintenance. This study assessed the influence of KGM on the digestive performance of a plant-based fishball (PFB) analogue during in vitro digestion via nuclear magnetic resonance (NMR) spectroscopy and rheological measurements. A total of 27 metabolites were identified, such as amino acids, sterols, saccharides, and fatty acids. Moreover, KGM generally decreased the released amino acids, glucose, and fatty acids. It is possible because KGM affected the metabolic pathways of amino acids and carbohydrates, based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Furthermore, PFB6.5 (PFB with 6.5% of KGM) digesta exhibited significantly higher yield stress τ0 (28.0 Pa), consistency coefficient K (46.25 Pa·Sn), and viscoelasticity G0* (749 Pa) than PFB3.5 (9.2 Pa, 14.66 Pa·Sn, 188 Pa). Besides, surface morphology indicated that fishball digesta became more porous, dissociative, and fragmented than PFB, revealing KGM reduced the breakdown of proteins. In conclusion, KGM prolonged the digestion and decreased metabolite release of PFB, which may help control appetite and reduce postprandial blood glucose levels.

Synthesis and characterization of a polycarboxylate superplasticizer modified by sodium hypophosphite

AbstractA sodium hypophosphite (SHP) modified polycarboxylatesuperplasticizer (P‐PCE) was synthesized successfully and the synthesis parameters were optimized through orthogonal experiment. Gel permeation chromatography (GPC), X‐ray photoelectron spectroscopy (XPS), 31P magic spinning nuclear magnetic resonance (31P MAS NMR) spectroscopy and elemental analysis measurements were used to characterize the molecular structure of P‐PCE. Effects of P‐PCE on the dispersing performance of cement paste were systematically investigated via mini slump test. The results showed that P‐PCE exhibited superior dispersing performance, more retarding hydration effect and better sulfate and clay tolerance than conventional PCE (C‐PCE). Results showed that the maximum flow of cement paste could reach up to 305 mm, while that of the C‐PCE was 285 mm.The maximum variation of adsorption of P‐PCE was 9% and 15% in the presence of sulfate and clay, whereas that of C‐PCE was 15% and 25%, respectively, leading to better sulfate and clay tolerance. These significant advantages could be ascribed to the high anion density and high calcium complexing capacity induced by introducingphosphinate group and phosphonate group into the molecular structure of P‐PCE. The as‐synthesized P‐PCE can be used as a kind of high performance superplasticizer in concrete engineering.

Evidence for distinct neuro-metabolic phenotypes in humans

Advances in magnetic resonance imaging have shown how individual differences in the structure and function of the human brain relate to health and cognition. The relationship between individual differences and the levels of neuro-metabolites, however, remains largely unexplored – despite the potential for the discovery of novel behavioural and disease phenotypes. In this study, we measured 14 metabolite levels, normalised as ratios to total-creatine, with 1H magnetic resonance spectroscopy (MRS) acquired from the bilateral anterior cingulate cortices of six healthy participants, repeatedly over a period of four months. ANOVA tests revealed statistically significant differences of 3 metabolites and 3 commonly used combinations (total-choline, glutamate + glutamine and total-N-acetylaspartate) between the participants, with scyllo-inositol (F=85, p=6e-26) and total-choline (F=39, p=1e-17) having the greatest discriminatory power. This was not attributable to structural differences. When predicting individuals from the repeated MRS measurements, a leave-one-out classification accuracy of 88% was achieved using a support vector machine based on scyllo-inositol and total-choline levels. Accuracy increased to 98% with the addition of total-N-acetylaspartate and myo-inositol – demonstrating the efficacy of combining MRS with machine learning and metabolomic methodology. These results provide evidence for the existence of neuro-metabolic phenotypes, which may be non-invasively measured using widely available 3 Tesla MRS. Establishing these phenotypes in a larger cohort and investigating their connection to brain health and function presents an important area for future study.