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https://www.readbyqxmd.com/read/28339206/utilizing-electron-spin-echo-envelope-modulation-to-distinguish-between-the-local-secondary-structures-of-an-%C3%AE-helix-and-an-amphipathic-310-helical-peptide
#1
Lauren Bottorf, Sophia Rafferty, Indra Dev Sahu, Robert M McCarrick, Gary A Lorigan
Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy was used to distinguish between the local secondary structures of an α-helix and a 310-helix. Previously, we have shown that ESEEM spectroscopy in combination with site-directed spin labeling (SDSL) and 2H-labeled amino acids (i) can probe the local secondary structure of α-helices, resulting in an obvious deuterium modulation pattern, where i+4 positions generally show larger 2H ESEEM peak intensities than i+3 positions. Here, we have hypothesized that due to the unique turn periodicities of an α-helix (3...
March 24, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28331947/-magnetic-resonance-spectroscopy-of-brain-tumors
#2
P Ditter, E Hattingen
BACKGROUND: Conventional magnetic resonance imaging (MRI) under consideration of clinical information enables the correct diagnosis and therapy for the majority of cerebral space-occupying lesions. Some important differential diagnoses, e. g. low vs. high-grade tumors, require additional MRI methods. OBJECTIVE: This article critically discusses the importance of magnetic resonance spectroscopy ((1)H-MRS) in brain tumors. MATERIAL AND METHODS: The concentration of normal and pathological brain metabolites can be non-invasively measured by (1)H-MRS...
March 22, 2017: Der Radiologe
https://www.readbyqxmd.com/read/28323638/fast-lesion-mapping-during-hifu-treatment-using-harmonic-motion-imaging-guided-focused-ultrasound-hmigfus-in-vitro-and-in-vivo
#3
Yang Han, Shutao Wang, Thomas Payen, Elisa Konofagou
The successful clinical application of high intensity focused ultrasound (HIFU) ablation depends on reliable monitoring of the lesion formation. Harmonic motion imaging guided focused ultrasound (HMIgFUS) is an ultrasound-based elasticity imaging technique, which monitors HIFU ablation based on the stiffness change of the tissue instead of the echo intensity change in conventional B-mode monitoring, rendering it potentially more sensitive to lesion development. Our group has shown that predicting the lesion location based on the radiation force-excited region is feasible during HMIgFUS...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28321637/the-time-course-of-short-term-hypertrophy-in-the-absence-of-eccentric-muscle-damage
#4
Matt S Stock, Jacob A Mota, Ryan N DeFranco, Katherine A Grue, A Unique Jacobo, Eunhee Chung, Jordan R Moon, Jason M DeFreitas, Travis W Beck
BACKGROUND: It has been proposed that the increase in skeletal muscle mass observed during the initial weeks of initiating a resistance training program is concomitant with eccentric muscle damage and edema. PURPOSE: We examined the time course of muscle hypertrophy during 4 weeks of concentric-only resistance training. METHODS: Thirteen untrained men performed unilateral concentric-only dumbbell curls and shoulder presses twice per week for 4 weeks...
March 20, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28318066/three-dimensional-ultrashort-echo-time-cones-t1%C3%AF-3d-ute-cones-t1%C3%AF-imaging
#5
Ya-Jun Ma, Michael Carl, Hongda Shao, Anthony S Tadros, Eric Y Chang, Jiang Du
We report a novel three-dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T1ρ preparation (UTE-Cones-T1ρ ) for quantitative T1ρ assessment of short T2 tissues in the musculoskeletal system. A basic 3D UTE-Cones sequence was combined with a spin-locking preparation pulse for T1ρ contrast. A relatively short TR was used to decrease the scan time, which required T1 measurement and compensation using 3D UTE-Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (Nsp ) after each T1ρ preparation and fat saturation...
March 20, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28315390/quantifying-the-dynamic-density-driven-convection-in-high-permeability-packed-beds
#6
Ying Teng, Lanlan Jiang, Yingting Fan, Yu Liu, Dayong Wang, Abuliti Abudula, Yongchen Song
The density driven convection phenomenon is expected to have a significant and positive role in CO2 geological storage capacity and safety. The onset and development of density-driven convective on the core scale is critical to understand the mass transfer mechanism. In this paper, laboratory experiments were conducted to investigate the density-driven convective in a vertical tube. The deuterium oxide (D2O)/manganese chloride (MnCl2) water solution in water or brine were as an analog for CO2-rich brine in original brine...
March 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28293719/placental-recess-accompanied-by-a-t2-dark-band-a-new-finding-for-diagnosing-placental-invasion
#7
Tomomi Sato, Naoko Mori, Osamu Hasegawa, Takeshi Shigihara, Keiya Fujimori, Kazuhiro Tasaki, Fumio Shishido
PURPOSE: Our aim was to assess the usefulness of a new magnetic resonance imaging (MRI) finding, the placental recess, for diagnosing placental invasion. METHODS: This retrospective study included 51 patients (mean age 34.1 years, range 26-43 years) with suspected placental invasion who underwent cesarean section. Preoperative MRI was performed using a 1.5-T unit and included axial, sagittal, and coronal T2-weighted imaging (T2WI) with half-Fourier fast spin-echo sequences...
March 14, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28289372/improved-quantification-of-cerebral-vein-oxygenation-using-partial-volume-correction
#8
Phillip G D Ward, Audrey P Fan, Parnesh Raniga, David G Barnes, David L Dowe, Amanda C L Ng, Gary F Egan
Purpose: Quantitative susceptibility mapping (QSM) enables cerebral venous characterization and physiological measurements, such as oxygen extraction fraction (OEF). The exquisite sensitivity of QSM to deoxygenated blood makes it possible to image small veins; however partial volume effects must be addressed for accurate quantification. We present a new method, Iterative Cylindrical Fitting (ICF), to estimate voxel-based partial volume effects for susceptibility maps and use it to improve OEF quantification of small veins with diameters between 1...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28286063/motion-corrected-dwi-with-integrated-t2-mapping-for-simultaneous-estimation-of-adc-t2-relaxation-and-perfusion-in-prostate-cancer
#9
M Skorpil, P Brynolfsson, M Engström
OBJECTIVE: Multiparametric magnetic resonance imaging (MRI) and PI-RADS (Prostate Imaging - Reporting and Data System) has become the standard to determine a probability score for a lesion being a clinically significant prostate cancer. T2-weighted and diffusion-weighted imaging (DWI) are essential in PI-RADS, depending partly on visual assessment of signal intensity, while dynamic-contrast enhanced imaging is less important. To decrease inter-rater variability and further standardize image evaluation, complementary objective measures are in need...
March 9, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28282586/mapping-axonal-density-and-average-diameter-using-non-monotonic-time-dependent-gradient-echo-mri
#10
Daniel Nunes, Tomás L Cruz, Sune N Jespersen, Noam Shemesh
White Matter (WM) microstructures, such as axonal density and average diameter, are crucial to the normal function of the Central Nervous System (CNS) as they are closely related with axonal conduction velocities. Conversely, disruptions of these microstructural features may result in severe neurological deficits, suggesting that their noninvasive mapping could be an important step towards diagnosing and following pathophysiology. Whereas diffusion based MRI methods have been proposed to map these features, they typically entail the application of powerful gradients, which are rarely available in the clinic, or extremely long acquisition schemes to extract information from parameter-intensive models...
February 28, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28275715/matched-behavioral-and-neural-adaptations-for-low-sound-level-echolocation-in-a-gleaning-bat-antrozous-pallidus
#11
Kevin R Measor, Brian C Leavell, Dustin H Brewton, Jeffrey Rumschlag, Jesse R Barber, Khaleel A Razak
In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat's auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL)...
January 2017: ENeuro
https://www.readbyqxmd.com/read/28273794/development-of-a-double-gauss-lens-based-setup-for-optoacoustic-applications
#12
Hojong Choi, Jae-Myung Ryu, Jung-Yeol Yeom
In optoacoustic (photoacoustic) systems, different echo signal intensities such as amplitudes, center frequencies, and bandwidths need to be compensated by utilizing variable gain or time-gain compensation amplifiers. However, such electronic components can increase system complexities and signal noise levels. In this paper, we introduce a double-Gauss lens to generate a large field of view with uniform light intensity due to the low chromatic aberrations of the lens, thus obtaining uniform echo signal intensities across the field of view of the optoacoustic system...
March 3, 2017: Sensors
https://www.readbyqxmd.com/read/28271596/team-based-approach-to-identify-cardiac-toxicity-in-critically-ill-hematopoietic-stem-cell-transplant-recipients
#13
Christopher E Dandoy, Sonata Jodele, Zachary Paff, Russel Hirsch, Thomas D Ryan, John L Jefferies, Michelle Cash, Seth Rotz, Abigail Pate, Michael D Taylor, Javier El-Bietar, Kasiani C Myers, Gregory Wallace, Adam Nelson, Michael Grimley, Thomas Pfeiffer, Adam Lane, Stella M Davies, Ranjit S Chima
INTRODUCTION: We observed pulmonary hypertension (PH), pericardial effusions, and left ventricular systolic dysfunction (LVSD) in multiple critically ill hematopoietic stem cell transplant (HSCT) recipients. We implemented routine structured echocardiography screening for HSCT recipients admitted to the pediatric intensive care unit (PICU) using a standardized multidisciplinary process. METHODS: HSCT recipients admitted to the PICU with respiratory distress, hypoxia, shock, and complications related to transplant-associated thrombotic microangiopathy were screened on admission and every 1-2 weeks thereafter...
March 8, 2017: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/28269978/differential-diagnosis-between-intraductal-papillary-mucinous-neoplasm-with-an-associated-invasive-carcinoma-and-pancreatic-ductal-adenocarcinoma-on-ultrasonography-the-utility-of-echo-intensity-and-contrast-enhancement
#14
Masato Saito, Naoki Hirokawa, Yoko Usami, Masanori Someya, Koh-Ichi Sakata
Purpose: The aim of this study was to investigate the utility of echo intensity and contrast enhancement in the differential diagnosis between intraductal papillary mucinous neoplasm with an associated invasive carcinoma (IPMN-IC) and pancreatic ductal adenocarcinoma (PDAC) on ultrasonography. Methods: This study included eight and 33 patients who had pathologically confirmed IPMN-IC and PDAC, respectively, and were enrolled for a comparative analysis of the sonographic features of the tumors...
February 4, 2017: Ultrasonography
https://www.readbyqxmd.com/read/28263827/a-fast-method-for-the-quantification-of-fat-fraction-and-relaxation-times-comparison-of-five-sites-of-bone-marrow
#15
Caroline Le Ster, Jérémy Lasbleiz, Stephan Kannengiesser, Raphaël Guillin, Giulio Gambarota, Hervé Saint-Jalmes
PURPOSE: Bone marrow is found either as red bone marrow, which mainly contains haematopoietic cells, or yellow bone marrow, which mainly contains adipocytes. In adults, red bone marrow is principally located in the axial skeleton. A recent study has introduced a method to simultaneously estimate the fat fraction (FF), the T1 and T2* relaxation times of water (T1w, T2*w) and fat (T1f and T2*f) in the vertebral bone marrow. The aim of the current study was to measure FF, T1w, T1f, T2*w and T2*f in five sites of bone marrow, and to assess the presence of regional variations...
March 2, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28263425/fast-bilateral-breast-coverage-with-high-spectral-and-spatial-resolution-hiss-mri-at-3t
#16
Milica Medved, Hui Li, Hiroyuki Abe, Deepa Sheth, Gillian M Newstead, Olufunmilayo I Olopade, Maryellen L Giger, Gregory S Karczmar
PURPOSE: To develop and assess a full-coverage, sensitivity encoding (SENSE)-accelerated breast high spatial and spectral resolution (HiSS) magnetic resonance imaging (MRI) within clinically reasonable times as a potential nonenhanced MRI protocol for breast density measurement or breast cancer screening. MATERIALS AND METHODS: Sixteen women with biopsy-proven cancer or suspicious lesions, and 13 women who were healthy volunteers or were screened for breast cancer, received 3T breast MRI exams, including SENSE-accelerated HiSS MRI, which was implemented as a submillimeter spatial resolution echo-planar spectroscopic imaging (EPSI) sequence...
March 6, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28249510/deconvolution-imaging-of-weak-reflective-pipe-defects-using-guided-wave-signals-captured-by-a-scanning-receiver
#17
Zeqing Sun, Anyu Sun, Bing-Feng Ju
Guided-wave echoes from weak reflective pipe defects are usually interfered by coherent noise and difficult to interpret. In this paper, a deconvolution imaging method is proposed to reconstruct defect images from synthetically focused guided-wave signals, with enhanced axial resolution. A compact transducer, circumferentially scanning around the pipe, is used to receive guided-wave echoes from discontinuities at a distance. This method achieves a higher circumferential sampling density than arrayed transducers-up to 72 sampling spots per lap for a pipe with a diameter of 180 mm...
February 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28240621/weighted-mean-of-signal-intensity-for-unbiased-fiber-tracking-of-skeletal-muscles-development-of-a-new-method-and-comparison-with-other-correction-techniques
#18
Chiara Giraudo, Stanislav Motyka, Michael Weber, Christoph Resinger, Feiweier Thorsten, Hannes Traxler, Siegfried Trattnig, Wolfgang Bogner
OBJECTIVES: The aim of this study was to investigate the origin of random image artifacts in stimulated echo acquisition mode diffusion tensor imaging (STEAM-DTI), assess the role of averaging, develop an automated artifact postprocessing correction method using weighted mean of signal intensities (WMSIs), and compare it with other correction techniques. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. The right calf and thigh of 10 volunteers were scanned on a 3 T magnetic resonance imaging scanner using a STEAM-DTI sequence...
February 25, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28224171/assessment-of-liver-iron-overload-by-3%C3%A2-t-mri
#19
A Paisant, A Boulic, E Bardou-Jacquet, E Bannier, G d'Assignies, F Lainé, B Turlin, Y Gandon
PURPOSE: To evaluate the performance and limitations of the signal intensity ratio method for quantifying liver iron overload at 3 T. METHODS: Institutional review board approval and written informed consent from all participants were obtained. One hundred and five patients were included prospectively. All patients underwent a liver biopsy with biochemical assessment of hepatic iron concentration and a 3 T MRI scan with 5 breath-hold single-echo gradient-echo sequences...
February 21, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28220365/binding-of-11-c-pittsburgh-compound-b-correlated-with-white-matter-injury-in-hypertensive-small-vessel-disease
#20
Tetsuya Hashimoto, Chiaki Yokota, Kazuhiro Koshino, Takashi Temma, Makoto Yamazaki, Satoshi Iguchi, Ryo Shimomura, Toshiyuki Uehara, Naoko Funatsu, Tenyu Hino, Kazuo Minematsu, Hidehiro Iida, Kazunori Toyoda
OBJECTIVE: (11)C-Pittsburgh compound-B ((11)C-PIB) positron emission tomography (PET) is used to visualize and quantify amyloid deposition in the brain cortex in pathological conditions such as Alzheimer's disease (AD). Intense (11)C-PIB retention is also observed in the white matter (WM) of both healthy individuals and AD patients. However, the clinical implications of this retention in brain WM have not been clarified. We investigated the relationship between the extent of white matter lesions (WMLs) and the binding potential of (11)C-PIB (BPND) in the WM in patients with hypertensive small vessel disease...
April 2017: Annals of Nuclear Medicine
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