Proton Magnetic Resonance Spectroscopy Study Research Articles

Thermal and optical characterization of multiple hydrogen bonded liquid crystals derived from mesogenic and non-mesogenic compounds: experimental and theoretical (DFT) studies

A set of new cyclic multiple hydrogen bonded liquid crystals (HBLCs) have been designed and synthesized from citric acid (CA) and 4-dodecyloxybenzoic acid (12OBA). The presence of intermolecular hydrogen bonds (H-bonds) between non-mesogenic and mesogenic compounds has been confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) studies. The hydrogen bonding interactions were explained from natural bond orbital (NBO) analysis using B3LYP/6-311G(d,p) level of theory. Additionally, the Mulliken atomic charges reveal the nature of charge distribution in the HBLC complex. The dynamics of phase transitions and the corresponding stability factor have been evaluated using polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and electrostatic potential (ESP) analysis. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of the CA+12OBA complex is theoretically calculated and experimentally verified. It is found that the variation in the mole ratio in mesogenic with non-mesogenic compound induces the stabilized nematic (N) and smectic X (Sm X) phases. Photocatalytic activity of the CA+12OBA HBLC complex reveals the usage of its optical applications.

Flocculation and antibacterial performance of dual coagulant system of modified cassava peel starch and alum

The present study examined the synergistic effect of alum-modified cassava peel starch as dual coagulants in removing total suspended solids and Escherichia coli in dam water. The optimisation study was carried out to evaluate the effects of pH, coagulant dosage, and settling time on the flocculation performance of the coagulants. Alum as sole coagulant and combination of alum and native cassava peel starch were also studied for comparison purpose. Characterisations of the coagulants using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy studies confirmed the successful modification of cassava peel starch. Characterization studies revealed changes in surface morphology, elemental distribution after the modification. Pores, rough surfaces and several new element including Cl and Ca were observed on the surface of the modified starch. The presence of important active groups such as citral that responsible for antimicrobial and flocculation function was also reflected in the modified starch coagulant. The optimisation study indicated distinct performance of alum-modified cassava peel starch compared to alum alone and alum-cassava peel starch in terms of both flocculation and antibacterial functionality. High removal of both TSS and E. coli was achieved with the treatment using the combination of alum-modified cassava peel starch with superior removal of 92.75% and 100%, respectively, within 10 min of settling time using the recommended working conditions of alum-modified cassava peel starch dosage of 7.5–50 mg/L at pH 7. Additionally, the characterisation of flocs indicated that the employment of alum as sole coagulant and alum combined with the modified starch possessed distinctive features. Scanning electron micrograph showed that the flocs formed using alum-modified cassava peel starch was highly compacted clusters with appearance of E.coli cells embedded in the floc matrix, whereas for alum as the sole coagulant, the flocs were irregular-shaped and aggregated. Besides, the difference in peak occurrence from analysis reflected different mechanisms of floc formation using alum alone and alum-modified cassava peel starch. From the floc analysis study, charge neutralisation, bridging and sweep flocculation were the mechanisms that are expected to govern the coagulation and flocculation process.

Intraindividual changes in brain GABA, glutamate, and glutamine during monitored abstinence from alcohol in treatment-naive individuals with alcohol use disorder.

Proton magnetic resonance spectroscopy (1 H-MRS) studies have demonstrated abnormal levels of a variety of neurometabolites in treatment-seeking individuals with moderate-severe alcohol use disorder (AUD) following acute withdrawal. In contrast, few studies have investigated neurochemical changes across early abstinence in less severe, treatment-naïve AUD. The present study, which represents the primary report of a research grant from ABMRF/The Alcohol Research Fund, measured dorsal anterior cingulate cortex (dACC) GABA, glutamate, and glutamine levels in treatment-naïve AUD (n = 23) via three 1 H-MRS scans spaced across a planned week of abstinence from alcohol. In addition to AUD participants, 12 light drinkers completed two scans, separated by 48 hours, to ensure that results in AUD were not produced by between-scan differences other than abstinence from alcohol. 1 H-MRS spectra were acquired in dACC at each scan using 2D J-resolved point-resolved spectroscopy. Linear mixed modeling results demonstrated a significant increase in GABA, but not glutamate or glutamine (Ps = .237-.626), levels between scans 1 and 2 (+8.88%, .041), with no difference between scans 2 and 3 (+1.00%, .836), in AUD but not LD (F = 1.24, .290) participants. Exploratory regression analyses tentatively revealed a number of significant prospective associations between changes in glutamine levels and heavy drinking, craving, and withdrawal symptoms. Most notably, the present study demonstrated return from abnormally low to normal GABA levels in treatment-naïve AUD within 3 days of their last drink; the pattern of results was consistent with glutamate and glutamine disturbances being exclusive to relatively more severe AUD.

Association of Cortical Glutamate and Working Memory Activation in Patients With Schizophrenia: A Multimodal Proton Magnetic Resonance Spectroscopy and Functional Magnetic Resonance Imaging Study

BackgroundCognitive deficits such as working memory (WM) impairment are core features of schizophrenia. One candidate marker for the integrity of synaptic neurotransmission necessary for cognitive processes is glutamate. It is frequently postulated that antipsychotic medication possibly alters functional mechanisms in the living brain. We tested in vivo for group differences in activation of the dorsolateral prefrontal cortex (DLPFC) during WM performance and the association with glutamate concentration in DLPFC depending on medication status. MethodsA total of 90 subjects (35 control subjects, 36 medicated patients, and 19 unmedicated patients) contributed magnetic resonance spectroscopy data. We estimated glutamate in left DLPFC. Subjects performed an n-back WM task (2-back vs. 0-back) during functional magnetic resonance imaging, and local activation in left DLPFC was measured. For analysis of association with medication status, we calculated linear regression models including an interaction effect with group. ResultsMedicated and unmedicated patients with schizophrenia showed impaired performance. We found significantly reduced WM activation in left DLPFC in medicated patients and a trendwise reduction in unmedicated patients as compared with control subjects. We found no group difference in local glutamate concentration. However, we found differential effects of medication status on the association between local glutamate concentration and WM activation in left DLPFC, with a positive association in unmedicated patients but not in medicated patients. ConclusionsWe provide evidence that WM-dependent activation is associated with glutamate concentration in unmedicated patients with schizophrenia. Our finding points to putative allostatic changes that affect the functioning of the brain and might be altered through medication.

Simultaneous Ligand and Receptor Tracking through NMR Spectroscopy Enabled by Distinct 19F Labels.

To probe ligand-receptor binding at the atomic-level, a frequent approach involves multidimensional nuclear magnetic resonance (NMR) spectroscopy experiments relying on 13C- and/or 15N-enrichment alongside 1H. Alternatively, the lack of fluorine in biomolecules may be exploited through specific incorporation of 19F nuclei into a sample. The 19F nucleus is highly sensitive to environmental changes and allows for one-dimensional NMR spectroscopic study, with perturbation to chemical shift and spin dynamics diagnostic of structural change, ligand binding, and modified conformational sampling. This was applied to the apelinergic system, which comprises a rhodopsin-like G protein-coupled receptor (the apelin receptor (AR)/APJ) and two families of cognate ligands, the apelin and apela (ELABELA/toddler) peptides. Specifically, AR fragments consisting of either the N-terminal tail and first transmembrane (TM) α-helix (AR55) or the first three transmembrane α-helices (TM1-3) were prepared with biosynthetic fluorotryptophan incorporation. Interactions of each AR fragment with a high-affinity, 2,4,5-trifluorophenylalanine labeled apelin analogue were compared by 19F NMR. Distinct ranges of 19F chemical shifts for ligand and receptor provide unambiguous tracking of both species, with distinct binding behaviour observed for each AR fragment implying that AR55 is not sufficient to recapitulate the physiological binding event. Site-specific perturbation was also apparent for the apelin analogue as a function of substitution site, indicating an orientational binding preference. As a whole, this strategy of distinctive 19F labelling for ligand and receptor provides a relatively fast (i.e., employing 1D NMR experiments) and highly sensitive method to simultaneously and definitively track binding in both species.

Glutamate levels in the anterior cingulate cortex in un-medicated first episode psychosis: a proton magnetic resonance spectroscopy study

Converging lines of evidence suggest that glutamatergic dysfunction may contribute to the pathophysiology of first episode psychosis. We investigated whether first episode psychosis patients free from all pharmacological treatments and illicit substances show cortical glutamatergic alterations. One-hundred and eleven volunteers including 65 healthy volunteers and 46 first episode psychosis patients free from all pharmacological treatments (28 drug naïve) underwent a proton magnetic resonance spectroscopy scan measuring glutamate levels in the bilateral anterior cingulate cortex. Symptom severity was measured using the Positive and Negative Syndrome Scale (PANSS) and cognition was measured using the Wechsler Adult Intelligence Scale (WAIS) digit symbol test. There were no differences in glutamate levels between patients and controls. These findings remained unchanged when adjusting for the effects of age, sex and ethnicity or when restricting the analyses to patients who were both medication naïve to all pharmacological treatments and illicit substances. Whilst these findings do not preclude glutamatergic alterations in psychosis, methodological advances are needed for us to investigate whether patients show alterations in other aspects of glutamate function, such as pre-synaptic glutamate or release.

Molecular characterization of particulate organic matter in full scale anaerobic digesters: An NMR spectroscopy study

This study assesses the molecular characteristics of particulate organic matter (POM) in agricultural and food waste digesters and elucidates the molecular properties of the recalcitrant POM fraction, which remains in the digestate after AD process. Molecular properties of POM in influent (substrate) and effluent (digestate) of seven full-scale AD plants (three agricultural waste and four food waste digesters) were characterized and compared using solid-state 13C cross-polarization magic angle spinning (CP-MAS) and solution-state 1H,13C heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. Comparison of the POM structural compositions of substrate and digestate from each AD plant revealed an enrichment of protein structures relative to the carbohydrates in most cases, implying a preferential degradation of the carbohydrates over proteins and/or increase of microbial biomass upon AD of agricultural and food wastes. Distinctive molecular structures of labile and recalcitrant fractions of POM, subjected to AD, were identified by comparing the NMR spectra of all substrate and digestate POM. Accordingly, the labile POM fraction in food and agricultural solid wastes is characterized by structural entities of lipids and starch-like carbohydrates, whereas recalcitrant POM structures resemble alkyl and aromatic subunits of amino acids, lignin, and polysaccharides with β-glycosidic linkages. This information serves as a basis to further explore optimization approaches for improving AD of the underutilized POM and the fate of organic matter in digestate-amended arable lands.

Monomeric Copper(II) Sites Supported on Alumina Selectively Convert Methane to Methanol.

Monomeric CuII sites supported on alumina, prepared using surface organometallic chemistry, convert CH4 to CH3 OH selectively. This reaction takes place by formation of CH3 O surface species with the concomitant reduction of two monomeric CuII sites to CuI , according to mass balance analysis, infrared, solid-state nuclear magnetic resonance, X-ray absorption, and electron paramagnetic resonance spectroscopy studies. This material contains a significant fraction of Cu active sites (22 %) and displays a selectivity for CH3 OH exceeding 83 %, based on the number of electrons involved in the transformation. These alumina-supported CuII sites reveal that C-H bond activation, along with the formation of CH3 O- surface species, can occur on pairs of proximal monomeric CuII sites in a short reaction time.

Monomeric Copper(II) Sites Supported on Alumina Selectively Convert Methane to Methanol

AbstractMonomeric CuII sites supported on alumina, prepared using surface organometallic chemistry, convert CH4 to CH3OH selectively. This reaction takes place by formation of CH3O surface species with the concomitant reduction of two monomeric CuII sites to CuI, according to mass balance analysis, infrared, solid‐state nuclear magnetic resonance, X‐ray absorption, and electron paramagnetic resonance spectroscopy studies. This material contains a significant fraction of Cu active sites (22 %) and displays a selectivity for CH3OH exceeding 83 %, based on the number of electrons involved in the transformation. These alumina‐supported CuII sites reveal that C−H bond activation, along with the formation of CH3O‐ surface species, can occur on pairs of proximal monomeric CuII sites in a short reaction time.

NMR characterization and evaluation of antibacterial and antiobiofilm activity of organic extracts from stationary phase batch cultures of five marine microalgae (Dunaliella sp., D. salina, Chaetoceros calcitrans, C. gracilis and Tisochrysis lutea)

The chemical composition of five marine microalgae (Dunaliella sp., Dunaliella salina, Chaetoceros calcitrans, Chaetoceros gracilis and Tisochrysis lutea) was investigated through nuclear magnetic resonance (NMR) spectroscopic study of the soluble material obtained by sequential extraction with hexane, ethyl acetate (AcOEt) and methanol of biomass from stationary phase cultures. Hexane extracted the major lipids present in the microalgae during the stationary phase of growth, which correspond to storage lipids. Triacylglycerols (TGs) were the only storage lipids produced by Dunaliella and Chaetoceros. In contrast, T. lutea predominantly stored polyunsaturated long-chain alkenones, with sterols also detected as minor components of the hexane extract. The molecular structure of brassicasterol was determined in T. lutea and the presence of squalene in this sample was also unequivocally detected. Monogalactosyldiacylglycerols (MGDGs) and pigments were concentrated in the AcOEt extracts. C. calcitrans and D. salina constituted an exception due to the high amount of TGs and glycerol produced, respectively, by these two strains. Chlorophylls a and b and β-carotene were the major pigments synthesized by Dunaliella and chlorophyll a and fucoxanthin were the only pigments detected in Chaetoceros and T. lutea. Information concerning the acyl chains present in TGs and MGDGs as well as the positional distribution of acyl chains on the glycerol moiety was obtained by NMR analysis of hexane and AcOEt extracts, with results consistent with those expected for the genera studied. Fatty acid composition of TGs in the two Dunaliella strains was different, with polyunsaturated acyl chains almost absent in the storage lipids produced by D. salina. Except in C. calcitrans, the polar nature of soluble compounds was inferred through the relative extraction yield using methanol as the extraction solvent. Glycerol was the major component of this fraction for the Dunaliella strains. In T. lutea 1,4/2,5-cyclohexanetetrol (CHT) and dimethylsulfoniopropionate (DMSP) preponderated. CHT was also the major polyol present in the Chaetoceros strains in which DMSP was not detected, but prominent signals of 2,3-dihydroxypropane-1-sulfonate (DHSP) were observed in the 1H NMR spectra of methanolic extracts. The presence of DHSP confirms the production of this metabolite by diatoms. In addition, several other minor compounds (digalactosyldiacyglycerols (DGDGs), sulphoquinovosyldiacylglycerols (SQDGs), amino acids, carbohydrates, scyllo-inositol, mannitol, lactic acid and homarine) were also identified in the methanolic extracts. The antibacterial and antibiofilm activities of the extracts were tested. The AcOEt extract from C. gracilis showed a moderate antibiofilm activity.

Evidence for a unique association between fronto-cortical glycine levels and recent heavy drinking in treatment naïve individuals with alcohol use disorder

Although the neurotransmitters/modulators glutamate and, more recently, glycine have been implicated in the development and maintenance of Alcohol Use Disorder (AUD) in preclinical research, human proton magnetic resonance spectroscopy (1H-MRS) studies have focused solely on the measurement of glutamate. The purpose of the present analysis was to examine the relative associations of brain glutamate and glycine levels with recent heavy drinking in 41 treatment naïve individuals with AUD using 1H-MRS. The present study is the first that we are aware of to report in vivo brain glycine levels from an investigation of addiction.Dorsal Anterior Cingulate Cortex (dACC) glutamate and glycine concentration estimates were obtained using Two-Dimensional J-Resolved Point Resolved Spectroscopy at 3 Tesla, and past 2-week summary estimates of alcohol consumption were assessed via the Timeline Followback method. Glutamate (β = −0.44, t = −3.09, p = 0.004) and glycine (β = −0.68, t = −5.72, p < 0.001) were each significantly, inversely associated with number of heavy drinking days when considered alone. However, when both variables were simultaneously entered into a single regression model, the effect of glutamate was no longer significant (β = −0.11, t = −0.81, p = 0.42) whereas the effect of glycine remained significant (β = −0.62, t = −4.38, p < 0.001).The present study extends the literature by demonstrating a unique, inverse association of brain glycine levels with recent heavy drinking in treatment naïve individuals with AUD. If replicated and extended, these data could lead to enhanced knowledge of how glycinergic systems change with alcohol consumption and AUD progression leading to pharmacological interventional/preventative strategies that modulate brain glycine levels.

Phosphonated mesoporous silica based composite membranes for high temperature proton exchange membrane fuel cells

Mesoporous Santa Barbara Amorphous (SBA-15) was synthesized, and it was grafted with phosphonate functionality using a simple two-step process involving chloromethylation and subsequent phosphonation. The phosphonated SBA-15 (PSBA-15) was characterized using Fourier transform infra-red (FTIR) spectroscopy, solid-state 13C nuclear magnetic resonance (NMR), 29Si NMR, and 31P NMR for confirming successful modification. Morphology features were verified by small angle X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy TEM analyses. Poly(styrene-ethylene-butylene-styrene) (PSEBS) was chosen as the base polymer and phosphonic acid functional groups were grafted onto the polymer using the aforementioned approach, where chloromethyl (-CH2Cl) groups were attached to the main chain using Friedel Craft’s alkylation, followed by the phosphonation of the chloromethylated polymer by the Michaels-Arbuzov reaction resulting in phosphonated PSEBS (PPSEBS). The functionalization was confirmed using NMR and FTIR spectroscopy studies. Composite PPSEBS/PSBA-15 membranes were fabricated with different filler concentrations (2, 4, 6, and 8%) of PSBA-15. Various studies such as water uptake, ion exchange capacity, and the proton conductivity of the composite membranes were undertaken with respect to fuel cell applications. From the studies, it was found that the PPSEBS/PSBA-15 membrane with 6 wt% of filler exhibited maximum proton conductivity of 8.62 mS/cm at 140 °C. Finally, membrane electrode assembly (MEA) was fabricated using PPSEBS/6% PSBA composite membrane, platinium (Pt) anode, and Pt cathode, and was tested in an in-house built fuel cell setup. A maximum power density of 226 mW/cm2 and an open circuit voltage of 0.89 V were achieved at 140 °C under un-humidified condition.

Neuronal loss or dysfunction in patients with early Lyme neuroborreliosis: a proton magnetic resonance spectroscopy study of the brain

BackgroundWe hypothesized that since Borrelia burgdorferi causes systemic inflammation and infects the brain, it may lead to alterations in cerebral metabolism, as measured by 1H-magnetic resonance spectroscopy (1H-MRS). The purpose of our study was to determine whether 1H-MRS could detect brain metabolite alterations in patients with early Lyme neuroborreliosis (LNB) in normal-appearing brain tissue on the conventional magnetic resonance imaging (MRI).MethodsTwenty-six patients diagnosed with early LNB and twenty-six healthy volunteers as a control group have been involved in the study. All of them underwent routine MRI protocol using 3.0-T MRI scanner. 1H-MRS examinations were performed with repetition time (TR) = 2000 ms, and echo time (TE) = 135 ms. Single voxels were positioned in the anterior and posterior parts of the right and left frontal lobes.ResultsWe found a statistically significant decrease of the N-acetylaspartate/creatine ratio within the anterior part of the right and left frontal lobes (p ≤ 0.001 and p = 0.001 respectively) and in the posterior part of the right and left frontal lobes (p ≤ 0.001 and 0.031) in the patients with LNB.ConclusionA significant reduction in NAA/Cr ratio in comparison with the controls suggests the presence of diffuse neuronal loss in patients with early LNB.

Hierarchical Hybrid Nanostructures Constructed by Fullerene and Molecular Tweezer.

For the construction of well-defined hierarchical superstructures of pristine [60]fullerene (C60) arrays, pyrene-based molecular tweezers (PT) were used as host molecules for catching and arranging C60 guest molecules. The formation of host-guest complexes was systematically studied in solution as well as in the solid state. Two-dimensional proton nuclear magnetic resonance spectroscopic studies revealed that PT-host and C60-guest complexes were closely related to the molecular self-assembly of PT. Ultraviolet and fluorescence spectroscopic titrations indicated the formation of stable 1:1 and 2:1 (PT/C60) complexes. From the nonlinear curve-fitting analysis, equilibrium constants for the 1:1 (log K1) and 2:1 (log K2) complexes were estimated to be 4.96 and 5.01, respectively. X-ray diffraction results combined with transmission electron microscopy observations clearly exhibited the construction of well-defined layered superstructures of the PT-host and C60-guest complexes. From electron mobility measurements, it was demonstrated that the well-defined hierarchical hybrid nanostructure incorporating a C60 array exhibited a high electron mobility of 1.7 × 10-2 cm2 V-1 s-1. This study can provide a guideline for the hierarchical hybrid nanostructures of host-guest complex and its applications.

Structure of Rubidium Borosilicate Glasses Studied by Nuclear Magnetic Resonance Spectroscopy

We present results of an 11B and 29Si nuclear magnetic resonance (NMR) spectroscopy study of the local anion structure of a series of borosilicate glasses in the Rb2O–B2O3–SiO2 system with different R = [Rb2O]/[B2O3] and K = [SiO2]/[B2O3] molar ratios. Relative integrated intensities of NMR lines are used to evaluate the fractions of boron atoms in three- and fourfold coordinations and the concentrations of various types of Qn silicate units. Comparison of the present data on the anion structure of the Rb2O–B2O3–SiO2 glasses studied here and data for previously studied glasses of analogous compositions in the Cs2O–B2O3–SiO2 system demonstrates that the difference in the degree of depolymerization in the anion structure of the glasses in these two systems is most pronounced at R = 1 and K = 2. At other values of these composition parameters (R = 0.43 and K = 1.43 or R = 2.33 and K = 3.33), the glasses with the compositions studied in the Rb2O–B2O3–SiO2 and Cs2O–B2O3–SiO2 systems are rather similar in local anion structure. The observed structural distinctions between the glasses make it possible to find out why they differ in glass transition temperature, as shown in a previous study by differential scanning calorimetry.

Defined Merocyanine Dye Stacks from a Dimer up to an Octamer by Spacer-Encoded Self-Assembly Approach.

A series of well-defined chromophore stacks is obtained upon self-assembly of merocyanine and bis(merocyanine) dyes in nonpolar solvents. Careful design of the spacer moieties linking the dipolar chromophores within the bis(merocyanine) dyes allows one to direct the dipole-dipole interaction driven aggregation into stacks of desired size from dimer up to octamer. The spacer-encoded self-assembly process was investigated by UV/vis absorption spectroscopy showing an increase of the hypsochromic shift with increasing stack size. The structure of the largest aggregate comprising eight chromophores was analyzed by 1D and 2D nuclear magnetic resonance spectroscopic studies revealing a perfectly interdigitated centrosymmetric organization of the dipolar dyes and concomitant annihilation of the ground state dipole moment is observed in the UV/vis absorption spectra. This unprecedented series of dye stacks from dimer to octamer enabled a systematic study of the optical absorption properties in dependence of the stack size disclosing that the absorption features can be rationalized by molecular exciton theory. Our results show that the noncovalent synthesis approach based on dipolar aggregation is suitable for the design of well-defined dye aggregates of specific size, allowing in-depth studies to manifest structure-property relationships.

Functional Connectivity and Metabolic Alterations in Medial Prefrontal Cortex in a Rat Model of Fetal Alcohol Spectrum Disorder: A Resting-State Functional Magnetic Resonance Imaging and in vivo Proton Magnetic Resonance Spectroscopy Study

Prenatal ethanol exposure alters brain structure, functional connectivity, and behavior in humans and rats. Behavioral changes include deficits in executive function, which requires cooperative activity between the frontal cortices and other brain regions. In this study, we analyzed the functional connectivity and neurochemical levels of the prefrontal cortex (PFC) using resting-state functional magnetic resonance imaging (rsfMRI) and proton magnetic resonance spectroscopy (¹H-MRS) in ethanol-exposed (Eth) and control (Ctr) rats. Pregnant Long-Evans rats were fed a liquid diet containing ethanol (2.1–6.46% v/v ethanol) from gestational days 6 to 21 (Eth). Ctr animals received an isocaloric, isonutritive liquid diet. In young adulthood, male and female offspring underwent in vivo MRI using a 7.0-Tesla system. ¹H-MRS from the PFC and whole brain rsfMRI were obtained on the animals. Seed-based functional connectivity analysis was performed with seeds placed in the PFC, matching the voxel of MRS. Male, but not female, Eth rats showed less functional connectivity between PFC and dorsal striatum than Ctr animals. In Eth males glucose levels were significantly lower, and in Eth females lower levels of phosphorylcholine but an increased gamma-aminobutyric acid/glutamate ratio were observed in the PFC compared with Ctr animals. Prenatal ethanol alters brain metabolism and functional connectivity of the PFC in a sex-dependent manner.

Network Connectivity and Crystallization in the Transparent Ferroelectric Nanocomposite LaBGeO5

The LaBGeO5 glass-ceramic composite is a transparent ferroelectric nanocomposite material that has come under attention for its ferroelectric properties and for its straightforward synthesis. The LaBGeO5 crystals-in-glass can be formed through controlled devitrification of glass, as well as through laser irradiation. Recent works have established that both the borate and germanate environments have significant differences in short-range order between the crystalline and glass forms of LaBGeO5. However, there are little available data on the connectivity of the different structural units. We present here a comprehensive nuclear magnetic resonance (NMR) spectroscopy study of the connectivity of crystalline LaBGeO5 and LaBGeO5 glass. Through a combination of 11B, 11B{10B}, 17O, and 139La NMR spectroscopies, we identify specific structural motifs in the glass. In particular, several structures are positively identified in the glass that are not present in the crystal, including BO2O–, BO2O––BO4–, and GeO6. We...

Differential levels of prefrontal cortex glutamate+glutamine in adults with antisocial personality disorder and bipolar disorder: A proton magnetic resonance spectroscopy study

As the main excitatory neurotransmitter in the central nervous system, glutamate, as measured in combination with glutamine (Glx), is implicated in several psychopathologies when levels are aberrant. One illness that shows heightened Glx levels is bipolar disorder (BD), an illness characterized by high impulsivity. In addition, although animal studies have reported elevated levels of Glx in aggressive and impulsive phenotypes, no study, to our knowledge, has reported Glx in the human cortex in relation to aggression. Here, we addressed the question of whether elevated levels of Glx would be present in patients with BD and antisocial personality disorder (ASPD), a condition associated with aggression and, like BD, also presents high impulsivity. We recruited individuals with ASPD (n = 18), individuals with BD (n = 16), and a healthy control group (n = 24). We used proton magnetic resonance spectroscopy to measure relative neurometabolite concentrations in the left dorsolateral prefrontal cortex (dlPFC) and supra-genual anterior cingulate cortex (ACC), two brain regions associated with impulsivity and behavior control. We found significantly elevated levels of Glx in the ASPD group relative to the BD and healthy control groups in the dlPFC (p = .014), and a positive correlation between Glx levels and aggression in the dlPFC in the ASPD group alone (r = .59, p = .026). These findings suggest a link between aggression in ASPD and Glx levels.

Effects of acute N-acetylcysteine challenge on cortical glutathione and glutamate in schizophrenia: A pilot in vivo proton magnetic resonance spectroscopy study

Findings from in vivo brain proton magnetic resonance spectroscopy (1H MRS) and preclinical studies have suggested region- and medication status-dependent increases in glutamate (Glu) levels and deficiencies in glutathione (GSH) levels in schizophrenia. N-acetylcysteine (NAC), a GSH synthesis precursor, has demonstrated modest clinical benefit in schizophrenia. The objective of this study was to examine the effects of acute administration of NAC on GSH and Glu levels measured with 1H MRS in 19 patients with schizophrenia and 20 healthy control subjects. Levels of GSH were acquired in dorsal anterior cingulate cortex (dACC), and those of Glu in dACC and medial prefrontal cortex (mPFC), at baseline and 60 min following acute oral administration of 2400 mg of NAC. No differences in the levels of GSH or Glu were found at baseline or following NAC administration between patients with schizophrenia and control subjects in either of the targeted brain regions. Future studies measuring GSH levels in brain regions previously found to exhibit glutamatergic abnormalities or using genetic polymorphisms, while controlling for the age and medication status of the cohorts, are warranted to better identify groups of patients more likely to respond to NAC and its mode of action and mechanisms.