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Functional MR

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https://www.readbyqxmd.com/read/28337970/quantum-coherence-phenomenon-in-disordered-bi2sete2-topological-single-crystal-effect-of-annealing
#1
E P Amaladass, T R Devidas, Shilpam Sharma, Awadhesh Mani
We report a comparative magnetotransport study on pristine and annealed Bi2SeTe2 single crystals. The pristine sample shows a metallic trend from 300 to 180 K, and an insulating behavior for T  <  180 K, whereas the annealed sample exhibits an insulating nature in the entire 4.2-300 K temperature range. Magnetoresistance (MR) of pristine and annealed samples reveals contrasting behaviour as a function of temperature (T) and magnetic field (B). At 4.2 K, the pristine sample shows weak antilocalization (WAL) behavior at low fields and transforms to weak localization (WL) behavior (negative MR) for B  >  2...
March 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28336868/eu-gd-codoped-yttria-nanoprobes-for-optical-and-t%C3%A2-weighted-magnetic-resonance-imaging
#2
Timur Sh Atabaev, Jong Ho Lee, Yong Cheol Shin, Dong-Wook Han, Ki Seok Choo, Ung Bae Jeon, Jae Yeon Hwang, Jeong A Yeom, Hyung-Kook Kim, Yoon-Hwae Hwang
Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y₂O₃ nanoprobes for potential applications in optical and magnetic resonance (MR) imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and photoluminescence (PL)...
February 10, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28334401/vocal-tract-images-reveal-neural-representations-of-sensorimotor-transformation-during-speech-imitation
#3
Daniel Carey, Marc E Miquel, Bronwen G Evans, Patti Adank, Carolyn McGettigan
Imitating speech necessitates the transformation from sensory targets to vocal tract motor output, yet little is known about the representational basis of this process in the human brain. Here, we address this question by using real-time MR imaging (rtMRI) of the vocal tract and functional MRI (fMRI) of the brain in a speech imitation paradigm. Participants trained on imitating a native vowel and a similar nonnative vowel that required lip rounding. Later, participants imitated these vowels and an untrained vowel pair during separate fMRI and rtMRI runs...
March 18, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28334159/characterization-of-white-matter-tracts-by-diffusion-mr-tractography-in-cat-and-ferret-that-have-similar-gyral-patterns
#4
Avilash Das, Emi Takahashi
The developmental relationships between gyral structures and white matter tracts have long been debated, but it is still difficult to discern whether they influence each other's development or are causally related. To explore this topic, this study used cats and ferrets as models for species that share similar gyral folding patterns and imaged with diffusion magnetic resonance imaging to compare white matter innervations in homologous gyri and other brain regions. Adult cat and ferret brains were analyzed via diffusion spectrum imaging tractography and homologous regions of interest were compared...
March 1, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28333338/drug-discovery-for-male-subfertility-using-high-throughput-screening-a-new-approach-to-an-unsolved-problem
#5
Sarah J Martins da Silva, Sean G Brown, Keith Sutton, Louise V King, Halil Ruso, David W Gray, Paul G Wyatt, Mark C Kelly, Christopher L R Barratt, Anthony G Hope
STUDY QUESTION: Can pharma drug discovery approaches be utilized to transform investigation into novel therapeutics for male infertility? SUMMARY ANSWER: High-throughput screening (HTS) is a viable approach to much-needed drug discovery for male factor infertility. WHAT IS KNOWN ALREADY: There is both huge demand and a genuine clinical need for new treatment options for infertile men. However, the time, effort and resources required for drug discovery are currently exorbitant, due to the unique challenges of the cellular, physical and functional properties of human spermatozoa and a lack of appropriate assay platform...
March 16, 2017: Human Reproduction
https://www.readbyqxmd.com/read/28333195/genome-wide-genetic-analyses-highlight-mitogen-activated-protein-kinase-mapk-signaling-in-the-pathogenesis-of-endometriosis
#6
Outi Uimari, Nilufer Rahmioglu, Dale R Nyholt, Katy Vincent, Stacey A Missmer, Christian Becker, Andrew P Morris, Grant W Montgomery, Krina T Zondervan
STUDY QUESTION: Do genome-wide association study (GWAS) data for endometriosis provide insight into novel biological pathways associated with its pathogenesis? SUMMARY ANSWER: GWAS analysis uncovered multiple pathways that are statistically enriched for genetic association signals, analysis of Stage A disease highlighted a novel variant in MAP3K4, while top pathways significantly associated with all endometriosis and Stage A disease included several mitogen-activated protein kinase (MAPK)-related pathways...
February 9, 2017: Human Reproduction
https://www.readbyqxmd.com/read/28332051/white-matter-involvement-on-dti-mri-in-cushing-s-syndrome-relates-to-mood-disturbances-and-processing-speed-a-case-control-study
#7
Patricia Pires, Alicia Santos, Yolanda Vives-Gilabert, Susan M Webb, Aitor Sainz-Ruiz, Eugenia Resmini, Iris Crespo, Manel de Juan-Delago, Beatriz Gómez-Anson
PURPOSE: Cushing's syndrome (CS) is an endocrine disorder due to prolonged exposure to cortisol. Recently, microstructural white matter (WM) alterations detected by diffusion tensor imaging (DTI) have been reported in CS patients, and related to depression, but other functional significances. remain otherwise unclear. We aimed at investigating in more depth mood symptoms in CS patients, and how these relate to cognition (information processing speed), and to WM alterations on DTI. METHODS: The sample comprised 35 CS patients and 35 healthy controls...
March 22, 2017: Pituitary
https://www.readbyqxmd.com/read/28330762/effect-of-whole-brain-irradiation-on-the-specific-brain-regions-in-a-rat-model-metabolic-and-histopathological-changes
#8
Soňa Bálentová, Petra Hnilicová, Dagmar Kalenská, Peter Murín, Eva Hajtmanová, Ján Lehotský, Marian Adamkov
Effect of ionizing radiation on the brain affects neuronal, glial, and endothelial cell population and lead to significant morphological, metabolic, and functional deficits. In the present study we investigated a dose- and time-dependent correlation between radiation-induced metabolic and histopathological changes. Adult male Wistar rats received a total dose of 35Gy delivered in 7 fractions (dose 5Gy per fraction) once per week in the same weekday during 7 consecutive weeks. Proton magnetic resonance spectroscopy ((1)H MRS), histochemistry, immunohistochemistry and confocal microscopy were used to determine whether radiation-induced alteration of the brain metabolites correlates with appropriate histopathological changes of neurogenesis and glial cell response in 2 neurogenic regions: the hippocampal dentate gyrus (DG) and the subventricular zone-olfactory bulb axis (SVZ-OB axis)...
March 19, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28329199/does-implantation-of-a-single-clip-provide-reliable-durability-after-transcatheter-mitral-repair-%C3%A2
#9
Nicola Buzzatti, Paolo Denti, Giovanni La Canna, Davide Schiavi, Luca Vicentini, Iside Stella Scarfò, Ilaria Caso, Michele De Bonis, Ottavio Alfieri
OBJECTIVES: A single MitraClip implant is often considered enough to achieve adequate mitral regurgitation (MR) reduction. The aim of this study was to compare MR recurrence in patients with an initial optimal result treated with a single clip versus those treated with two clips. METHODS: From October 2008 to May 2016, 322 patients were treated with the MitraClip procedure at our institution. We retrospectively selected all patients treated for functional MR (FMR) and degenerative MR (DMR) aetiologies with residual MR ≤1+, excluding patients who required >2 clips...
February 27, 2017: European Journal of Cardio-thoracic Surgery
https://www.readbyqxmd.com/read/28329173/mitral-valve-repair-for-secondary-mitral-regurgitation-in-non-ischaemic-dilated-cardiomyopathy-is-associated-with-left-ventricular-reverse-remodelling-and-increase-of-forward-flow
#10
Vasileios Kamperidis, Suzanne E van Wijngaarden, Philippe J van Rosendael, William Kok Fai Kong, Madelien V Regeer, Frank van der Kley, Georgios Sianos, Nina Ajmone Marsan, Jeroen J Bax, Victoria Delgado
Aims: It remains unclear whether surgical or transcatheter mitral valve repair for secondary mitral regurgitation (MR) in patients with non-ischaemic cardiomyopathy reverse the underlying left ventricular (LV) pathophysiology. We hypothesized that mitral valve repair improves LV systolic function and forward flow and induces LV reverse remodelling in this group of patients. Methods and results: Seventy-six patients (65 ± 14 years old, 43% male) with non-ischaemic cardiomyopathy and moderate to severe chronic secondary MR treated successfully with transcatheter or surgical mitral valve repair were evaluated...
February 23, 2017: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28328939/multimodal-mr-imaging-reveals-large-scale-structural-and-functional-connectivity-changes-in-profound-early-blindness
#11
Corinna M Bauer, Gabriella V Hirsch, Lauren Zajac, Bang-Bon Koo, Olivier Collignon, Lotfi B Merabet
In the setting of profound ocular blindness, numerous lines of evidence demonstrate the existence of dramatic anatomical and functional changes within the brain. However, previous studies based on a variety of distinct measures have often provided inconsistent findings. To help reconcile this issue, we used a multimodal magnetic resonance (MR)-based imaging approach to provide complementary structural and functional information regarding this neuroplastic reorganization. This included gray matter structural morphometry, high angular resolution diffusion imaging (HARDI) of white matter connectivity and integrity, and resting state functional connectivity MRI (rsfcMRI) analysis...
2017: PloS One
https://www.readbyqxmd.com/read/28327774/huge-magnetoresistance-induced-by-half-metal-semiconductor-phase-transition-in-a-one-dimensional-spin-chain-a-first-principles-study
#12
Jing Zeng, Ke-Qiu Chen
In experimental studies, magnetoresistance (MR) values of 10(3) are hard to reach for conventional single-molecule spin-valves. Motivated by a recent experiment [Nano Lett., 2016, 16, 577-582], where tailored Co-salophene-based all-spin molecular devices are successfully realized, we demonstrate the functionality of a Co-salophene-based spin chain without magnetic electrodes. By using nonequilibrium Green's functions in combination with density functional theory, we find that the maximum MR ratio of this spin chain can reach 10(6) by manipulating its spins in a controlled way, which is several orders of magnitude higher than previously reported experimental values...
March 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28324065/neurod-factors-discriminate-mineralocorticoid-from-glucocorticoid-receptor-dna-binding-in-the-male-rat-brain
#13
Lisa T C M van Weert, Jacobus C Buurstede, Ahmed Mahfouz, Pamela S M Braakhuis, J Annelies E Polman, Hetty C M Sips, Benno Roozendaal, Judit Balog, E Ronald de Kloet, Nicole A Datson, Onno C Meijer
In the limbic brain, mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) both function as receptors for the naturally occurring glucocorticoids (corticosterone/cortisol), but mediate distinct effects on cellular physiology via transcriptional mechanisms. The transcriptional basis for specificity of these MR- versus GR-mediated effects is unknown. To address this conundrum we have identified the extent of MR/GR DNA binding selectivity in the rat hippocampus using chromatin immunoprecipitation followed by sequencing (ChIP-seq)...
January 24, 2017: Endocrinology
https://www.readbyqxmd.com/read/28323995/renin-phenotypes-characterize-vascular-disease-autonomous-aldosteronism-and-mineralocorticoid-receptor-activity
#14
Gregory L Hundemer, Rene Baudrand, Jenifer M Brown, Gary Curhan, Gordon H Williams, Anand Vaidya
Context: Mild cases of autonomous aldosterone secretion may go unrecognized using current diagnostic criteria for primary aldosteronism (PA). Objective: To investigate whether the inability to stimulate renin serves as a biomarker for unrecognized autonomous aldosterone secretion and mineralocorticoid receptor (MR) activation. Participants: 663 normotensive and mildly hypertensive participants, who were confirmed to not have PA using current guideline criteria and were on no antihypertensive medications...
February 17, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28323680/transient-global-amnesia-commentary-on-trip-gabriel-s-first-person-account
#15
Howard S Kirshner
This paper comments on a companion article, a first-person account of an episode of transient global amnesia written by New York Times reporter Trip Gabriel (Gabriel T. 2017. Cogn Behav Neurol. 30:1-4). Mr Gabriel describes having no memories of a cold, rainy day that he had spent on a sailboat competing in two races. The episode may have been triggered by his exposure to water. Afterward, the skipper recalled that Mr Gabriel had functioned fine on the boat, although after returning to shore he needed help finding his car...
March 2017: Cognitive and Behavioral Neurology: Official Journal of the Society for Behavioral and Cognitive Neurology
https://www.readbyqxmd.com/read/28321914/a-compact-0-5%C3%A2-t-mr-elastography-device-and-its-application-for-studying-viscoelasticity-changes-in-biological-tissues-during-progressive-formalin-fixation
#16
Jürgen Braun, Heiko Tzschätzsch, Clara Körting, Angela Ariza de Schellenberger, Marika Jenderka, Toni Drießle, Michael Ledwig, Ingolf Sack
PURPOSE: To develop a method of compact tabletop magnetic resonance elastography (MRE) for rheological tests of tissue samples and to measure changes in viscoelastic powerlaw constants of liver and brain tissue during progressive fixation. METHODS: A 10-mm bore, 0.5-T permanent-magnet-based MRI system was equipped with a gradient-amplifier-controlled piezo-actuator and motion-sensitive spin echo sequence for inducing and measuring harmonic shear vibrations in cylindrical samples...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28321787/a-mathematical-theory-of-shape-and-neuro-fuzzy-methodology-based-diagnostic-analysis-a-comparative-study-on-early-detection-and-treatment-planning-of-brain-cancer
#17
Subrata Kar, D Dutta Majumder
BACKGROUND: Investigation of brain cancer can detect the abnormal growth of tissue in the brain using computed tomography (CT) scans and magnetic resonance (MR) images of patients. The proposed method classifies brain cancer on shape-based feature extraction as either benign or malignant. The authors used input variables such as shape distance (SD) and shape similarity measure (SSM) in fuzzy tools, and used fuzzy rules to evaluate the risk status as an output variable. We presented a classifier neural network system (NNS), namely Levenberg-Marquardt (LM), which is a feed-forward back-propagation learning algorithm used to train the NN for the status of brain cancer, if any, and which achieved satisfactory performance with 100% accuracy...
March 20, 2017: International Journal of Clinical Oncology
https://www.readbyqxmd.com/read/28321594/disrupted-functional-connectivity-of-periaqueductal-gray-subregions-in-episodic-migraine
#18
Zhiye Chen, Xiaoyan Chen, Mengqi Liu, Shuangfeng Liu, Lin Ma, Shengyuan Yu
BACKGROUND: The periaqueductal gray (PAG) dysfunction was recognized in migraine, and the altered dysfunction of PAG subregions were not totally detected up to now. The aim of this study is to investigate the altered functional connectivity of PAG subregions in EM patients. METHODS: The brain structural images and resting state functional MR imaging (rs-fMRI) data were obtained from 18 normal controls (NC) and 18 EM patients on 3.0 T MR system. Seven subregions of PAG were classified as bilateral ventrolateral PAG (vlPAG), lateral PAG (lPAG), dorsolateral PAG (dlPAG) and dorsomedial PAG (dmPAG)...
December 2017: Journal of Headache and Pain
https://www.readbyqxmd.com/read/28321415/assessment-of-longitudinal-reproducibility-of-mice-lv-function-parameters-at-11-7%C3%A2-t-derived-from-self-gated-cine-mri
#19
Zhi Zuo, Anne Subgang, Alireza Abaei, Wolfgang Rottbauer, Detlef Stiller, Genshan Ma, Volker Rasche
The objective of this work was the assessment of the reproducibility of self-gated cardiac MRI in mice at ultra-high-field strength. A group of adult mice (n = 5) was followed over 360 days with a standardized MR protocol including reproducible animal position and standardized planning of the scan planes. From the resulting CINE MRI data, global left ventricular (LV) function parameters including end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and left ventricular mass (LVM) were quantified...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28321004/avj-514-trial%C3%A3-baseline-characteristics-and-30-day-outcomes-following-mitraclip-%C3%A2-treatment-in-a-japanese-cohort
#20
Kentaro Hayashida, Satoshi Yasuda, Takashi Matsumoto, Makoto Amaki, Shingo Mizuno, Tetsuya Tobaru, Kentaro Jujo, Tatsushi Ootomo, Junichi Yamaguchi, Keiichi Fukuda, Shigeru Saito, Elyse Foster, Atif Qasim, Ryohei Yozu, Morimasa Takayama
BACKGROUND: The MitraClip(®)system is a transcatheter-based therapeutic option for patients with chronic mitral regurgitation (MR) who are at high risk for surgery. A prospective, multicenter, single-arm study was initiated to confirm the transferability of this system to Japan.Methods and Results:Patients with symptomatic chronic moderate-to-severe (3+) or severe (4+) functional or degenerative MR with a Society of Thoracic Surgery (STS) score ≥8%, or the presence of 1 predefined risk factor were enrolled...
March 17, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
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