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Discover the most talked about and latest scientific content & concepts.

Concept: In vivo magnetic resonance spectroscopy

244

Intrusive memories, images, and hallucinations are hallmark symptoms of psychiatric disorders. Although often attributed to deficient inhibitory control by the prefrontal cortex, difficulty in controlling intrusive thoughts is also associated with hippocampal hyperactivity, arising from dysfunctional GABAergic interneurons. How hippocampal GABA contributes to stopping unwanted thoughts is unknown. Here we show that GABAergic inhibition of hippocampal retrieval activity forms a key link in a fronto-hippocampal inhibitory control pathway underlying thought suppression. Subjects viewed reminders of unwanted thoughts and tried to suppress retrieval while being scanned with functional magnetic resonance imaging. Suppression reduced hippocampal activity and memory for suppressed content. (1)H magnetic resonance spectroscopy revealed that greater resting concentrations of hippocampal GABA predicted better mnemonic control. Higher hippocampal, but not prefrontal GABA, predicted stronger fronto-hippocampal coupling during suppression, suggesting that interneurons local to the hippocampus implement control over intrusive thoughts. Stopping actions did not engage this pathway. These findings specify a multi-level mechanistic model of how the content of awareness is voluntarily controlled.

Concepts: Brain, Nuclear magnetic resonance, Magnetic resonance imaging, Memory, Cerebrum, Hippocampus, Limbic system, In vivo magnetic resonance spectroscopy

208

Creativity is a vast construct, seemingly intractable to scientific inquiry-perhaps due to the vague concepts applied to the field of research. One attempt to limit the purview of creative cognition formulates the construct in terms of evolutionary constraints, namely that of blind variation and selective retention (BVSR). Behaviorally, one can limit the “blind variation” component to idea generation tests as manifested by measures of divergent thinking. The “selective retention” component can be represented by measures of convergent thinking, as represented by measures of remote associates. We summarize results from measures of creative cognition, correlated with structural neuroimaging measures including structural magnetic resonance imaging (sMRI), diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS). We also review lesion studies, considered to be the “gold standard” of brain-behavioral studies. What emerges is a picture consistent with theories of disinhibitory brain features subserving creative cognition, as described previously (Martindale, 1981). We provide a perspective, involving aspects of the default mode network (DMN), which might provide a “first approximation” regarding how creative cognition might map on to the human brain.

Concepts: Brain, Medical imaging, Neuroimaging, Nuclear magnetic resonance, Magnetic resonance imaging, Thought, Diffusion MRI, In vivo magnetic resonance spectroscopy

174

This work aimed to determine whether (1)H magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are correlated with years of meditation and psychological variables in long-term Zen meditators compared to healthy non-meditator controls.

Concepts: Brain, Medical imaging, Brain tumor, Nuclear magnetic resonance, Magnetic resonance imaging, Diffusion MRI, In vivo magnetic resonance spectroscopy, Zen

167

Purpose: To flesh out the ESUR guidelines for the standardized interpretation of multiparametric magnetic resonance imaging (mMRI) for the detection of prostate cancer and to present a graphic reporting scheme for improved communication of findings to urologists. Materials and Methods: The ESUR has recently published a structured reporting system for mMRI of the prostate (PI-RADS). This system involves the use of 5-point Likert scales for grading the findings obtained with different MRI techniques. The mMRI includes T2-weighted MRI, diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy. In a first step, the fundamentals of technical implementation were determined by consensus, taking into account in particular the German-speaking community. Then, representative images were selected by consensus on the basis of examinations of the three institutions. In addition, scoring intervals for an aggregated PI-RADS score were determined in consensus. Results: The multiparametric methods were discussed critically with regard to implementation and the current status. Criteria used for grading mMRI findings with the PI-RADS classification were concretized by succinct examples. Using the consensus table for aggregated scoring in a clinical setting, a diagnosis of suspected prostate cancer should be made if the PI-RADS score is 4 or higher (≥ 10 points if 3 techniques are used or ≥ 13 points if 4 techniques are used). Finally, a graphic scheme was developed for communicating mMRI prostate findings. Conclusion: Structured reporting according to the ESUR guidelines contributes to quality assurance by standardizing prostate mMRI, and it facilities the communication of findings to urologists.

Concepts: Cancer, Medical imaging, Prostate cancer, Nuclear magnetic resonance, Magnetic resonance imaging, Radiology, Diffusion MRI, In vivo magnetic resonance spectroscopy

91

Group B Streptococcus (GBS) infection is a major cause of morbidity and mortality in infants. The major risk factor for GBS disease is maternal and subsequent infant colonisation. It is unknown whether human milk oligosaccharides (HMOs) protect against GBS colonisation. HMO production is genetically determined and linked to the Lewis antigen system. We aimed to investigate the association between HMOs and infant GBS colonisation between birth and postnatal day 90. Rectovaginal swabs were collected at delivery, as well as colostrum/breast milk, infant nasopharyngeal and rectal swabs at birth, 6 days and days 60-89 postpartum from 183 Gambian mother/infant pairs. GBS colonisation and serotypes were determined using culture and PCR. (1)H nuclear magnetic resonance spectroscopy was used to characterise the mother’s Lewis status and HMO profile in breast milk. Mothers who were Lewis-positive were significantly less likely to be colonised by GBS (X (2)=12.50, P<0.001). Infants of Lewis-positive mothers were less likely GBS colonised at birth (X (2)=4.88 P=0.03) and more likely to clear colonisation between birth and days 60-89 than infants born to Lewis-negative women (P=0.05). There was no association between Secretor status and GBS colonisation. In vitro work revealed that lacto-N-difucohexaose I (LNDFHI) correlated with a reduction in the growth of GBS. Our results suggest that HMO such as LNDFHI may be a useful adjunct in reducing maternal and infant colonisation and hence invasive GBS disease. Secretor status offers utility as a stratification variable in GBS clinical trials.

Concepts: Immune system, Childbirth, Infant, Nuclear magnetic resonance, Milk, Breastfeeding, Breast, In vivo magnetic resonance spectroscopy

37

Martensitic transition is a solid-state phase transition involving cooperative movement of atoms, mostly studied in metallurgy. The main characteristics are low transition barrier, ultrafast kinetics, and structural reversibility. They are rarely observed in molecular crystals, and hence the origin and mechanism are largely unexplored. Here we report the discovery of martensitic transition in single crystals of two different organic semiconductors. In situ microscopy, single-crystal X-ray diffraction, Raman and nuclear magnetic resonance spectroscopy, and molecular simulations combined indicate that the rotating bulky side chains trigger cooperative transition. Cooperativity enables shape memory effect in single crystals and function memory effect in thin film transistors. We establish a molecular design rule to trigger martensitic transition in organic semiconductors, showing promise for designing next-generation smart multifunctional materials.

Concepts: Electron, X-ray, Fundamental physics concepts, Chemistry, Nuclear magnetic resonance, Magnetic resonance imaging, Silicon, In vivo magnetic resonance spectroscopy

30

Aquacultures are of great economic importance worldwide but pollute pristine headwater streams, lakes, and estuaries. However, there are no in-depth studies of the consequences of aquacultures on dissolved organic matter (DOM) composition and structure. We performed a detailed molecular level characterization of aquaculture DOM quality and its bacterial degradation using four salmon aquacultures in Chile. Fluorescence measurements, ultrahigh-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy of the DOM revealed specific and extensive molecular alterations caused by aquacultures. Aquacultures released large quantities of readily bioavailable metabolites (primarily carbohydrates and peptides/proteins, and lipids), causing the organic matter downstream of all the investigated aquacultures to deviate strongly from the highly processed, polydisperse and molecularly heterogeneous DOM found in pristine rivers. However, the upstream individual catchment DOM signatures remained distinguishable at the downstream sites. The benthic algal biovolume decreased and the bacterial biovolume and production increased downstream of the aquacultures, shifting stream ecosystems to a more heterotrophic state and thus impairing the ecosystem health. The bacterial DOM degradation rates explain the attenuation of aquaculture DOM within the subsequent stream reaches. This knowledge may aid the development of improved waste processing facilities and may help to define emission thresholds to protect sensitive stream ecosystems.

Concepts: Spectroscopy, Molecular biology, Nuclear magnetic resonance, River, Stream, In vivo magnetic resonance spectroscopy, Aquaculture, Geomorphology

28

Investigation of the 95% EtOH extract of red yeast rice fermented with the pink mutant of the fungus Monascus purpureus BCRC 38108 led to the isolation of three new azaphilone derivatives, namely monascusazaphilones A-C (1-3), together with two known compounds. Compounds 1-3 were isolated from this species for the first time. Their structures were elucidated by 1-D and 2-D nuclear magnetic resonance spectroscopy together with HR-ESI-MS analysis and comparison of the spectroscopic data with those reported in the literatures. All isolates were evaluated for their inhibitory effects on nitric oxide (NO) production by macrophages. Among the isolates, compound 1 demonstrated stronger inhibition on NO production.

Concepts: Spectroscopy, Carbon dioxide, Ethanol, Nuclear magnetic resonance, Magnetic resonance imaging, In vivo magnetic resonance spectroscopy, Red yeast rice, Monascus purpureus

27

Metabolomic profiling of exhaled breath condensate offers opportunities for the development of noninvasive diagnostics in asthma. We aimed to determine and validate discriminatory metabolomic profiles in adult asthma and to explore profiles in clinically relevant disease phenotypes.

Concepts: Medical terms, Spin, Nuclear magnetic resonance, Magnetic resonance imaging, In vivo magnetic resonance spectroscopy, Resonance

27

The mixed glass former effect (MGFE) is defined as a non-linear and non-additive change in the ionic conductivity with changing glass former composition at constant modifier composition. In this study, sodium borophosphate 0.35 Na2O + 0.65 [xB2O3 + (1-x)P2O5], 0 ≤ x ≤ 1 glasses which have been shown to exhibit a positive MGFE, have been prepared and examined through Raman and 11B and 31P Magic Angle Spinning - Nuclear Magnetic Resonance (MAS-NMR) Spectroscopies. Through examination of the short range order (SRO) structures found in the ternary glasses, it was determined that the glass former, B for 0.1 ≤ x ≤ 0.7 and P for 0.7 ≤ x ≤ 0.9, is “over modified” and contains more Na+ ions then would be expected from the binary sodium borate, x = 1, and sodium phosphate, x = 0, glasses, respectively. Changes in the intermediate range order (IRO) structures were suggested by changes in the NMR chemical shifts and Raman wavenumber shifts over the composition range x in Raman and MAS- NMR spectras. The changes observed in the chemical shifts of 31P MAS-NMR spectra with x are too large to be caused solely by changing sodium modification of the glasses and this indicates that inter-network bonding between phosphorous to boron through bridging oxygens (BOs), P-O-B, must be a major contributor to the IRO structure of these glasses. While not fully developed, a first order thermodynamic analysis based upon the Gibbs' free energies of formation of the various SRO structural units in this system has been applied and can be used to account for the preferential formation of tetrahedral boron groups in these glasses. This preference for tetrahedral boron units appears to be a predominate cause of the changing modifier to glass former ratio with composition x in these ternary mixed glass former glasses.

Concepts: Spectroscopy, Nuclear magnetic resonance, Chemical shift, Magnetic resonance imaging, In vivo magnetic resonance spectroscopy, Magic angle spinning, Magic angle, Boron