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https://www.readbyqxmd.com/read/28922760/the-roles-of-pleiotropy-and-close-linkage-as-revealed-by-association-mapping-of-yield-and-correlated-traits-of-wheat-triticum-aestivum-l
#1
Albert W Schulthess, Jochen C Reif, Jie Ling, Jörg Plieske, Sonja Kollers, Erhard Ebmeyer, Viktor Korzun, Odile Argillier, Gunther Stiewe, Martin W Ganal, Marion S Röder, Yong Jiang
Grain yield (GY) of bread wheat (Triticum aestivum L.) is quantitatively inherited. Correlated GY-syndrome traits such as plant height (PH), heading date (HD), thousand grain weight (TGW), test weight (TW), grains per ear (GPE), and ear weight (EW) influence GY. Most quantitative genetics studies assessed the multiple-trait (MT) complex of GY-syndrome using single-trait approaches, and little is known about its underlying pleiotropic architecture. We investigated the pleiotropic architecture of wheat GY-syndrome through MT association mapping (MT-GWAS) using 372 varieties phenotyped in up to eight environments and genotyped with 18 832 single nucleotide polymorphisms plus 24 polymorphic functional markers...
July 10, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28913930/accuracy-repeatability-and-interplatform-reproducibility-of-t1-quantification-methods-used-for-dce-mri-results-from-a-multicenter-phantom-study
#2
Octavia Bane, Stefanie J Hectors, Mathilde Wagner, Lori L Arlinghaus, Madhava P Aryal, Yue Cao, Thomas L Chenevert, Fiona Fennessy, Wei Huang, Nola M Hylton, Jayashree Kalpathy-Cramer, Kathryn E Keenan, Dariya I Malyarenko, Robert V Mulkern, David C Newitt, Stephen E Russek, Karl F Stupic, Alina Tudorica, Lisa J Wilmes, Thomas E Yankeelov, Yi-Fei Yen, Michael A Boss, Bachir Taouli
PURPOSE: To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. METHODS: A T1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and a variable flip angle (VFA) protocol using seven flip angles, as well as site-specific protocols (VFA with different flip angles, variable repetition time, proton density, and Look-Locker inversion recovery)...
September 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28893660/a-new-rf-transmit-coil-for-foot-and-ankle-imaging-at-7t-mri
#3
Tales Santini, Junghwan Kim, Sossena Wood, Narayanan Krishnamurthy, Nadim Farhat, Carlos Maciel, Shailesh Raval, Tiejun Zhao, Tamer Ibrahim
A four-channel Tic-Tac-Toe (TTT) transmit RF coil was designed and constructed for foot and ankle imaging at 7T MRI. Numerical simulations using an in-house developed FDTD package and experimental analyses using a homogenous phantom show an excellent agreement in terms of B1(+) field distribution and s-parameters. Simulations performed on an anatomically detailed human lower leg model demonstrated an B1(+) field distribution with a coefficient of variation (CV) of 23.9%/15.6%/28.8% and average B1(+) of 0.33μT/0...
September 8, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28856778/temporally-resolved-parametric-assessment-of-z-magnetization-recovery-topaz-dynamic-myocardial-t1-mapping-using-a-cine-steady-state-look-locker-approach
#4
Sebastian Weingärtner, Chetan Shenoy, Benedikt Rieger, Lothar R Schad, Jeanette Schulz-Menger, Mehmet Akçakaya
PURPOSE: To develop and evaluate a cardiac phase-resolved myocardial T1 mapping sequence. METHODS: The proposed method for temporally resolved parametric assessment of Z-magnetization recovery (TOPAZ) is based on contiguous fast low-angle shot imaging readout after magnetization inversion from the pulsed steady state. Thereby, segmented k-space data are acquired over multiple heartbeats, before reaching steady state. This results in sampling of the inversion-recovery curve for each heart phase at multiple points separated by an R-R interval...
August 30, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28855282/discovery-of-a-novel-stem-rust-resistance-allele-in-durum-wheat-that-exhibits-differential-reactions-to-ug99-isolates
#5
Jayaveeramuthu Nirmala, Jyoti Saini, Maria Newcomb, Pablo Olivera, Sam Gale, Daryl Klindworth, Elias Elias, Luther Talbert, Shiaoman Chao, Justin Faris, Steven Xu, Yue Jin, Matthew N Rouse
Wheat stem rust, caused by Puccinia graminis f. sp. tritici Erikss. & E. Henn, can incur yield losses on susceptible cultivars of durum wheat, Triticum turgidum ssp. durum (Desf.) Husnot. Though several durum cultivars possess the stem rust resistance gene Sr13, additional genes in durum wheat effective against emerging virulent races have not been described. Durum line 8155-B1 confers resistance against the P. graminis f. sp. tritici race TTKST, the variant race of the Ug99 race group with additional virulence to wheat stem rust resistance gene Sr24 However, 8155-B1 does not confer resistance to the first-described race in the Ug99 race group: TTKSK...
August 29, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28845431/mapping-qtl-for-root-and-shoot-morphological-traits-in-a-durum-wheat%C3%A2-%C3%A3-%C3%A2-t-dicoccum-segregating-population-at-seedling-stage
#6
Anna Iannucci, Daniela Marone, Maria Anna Russo, Pasquale De Vita, Vito Miullo, Pina Ferragonio, Antonio Blanco, Agata Gadaleta, Anna Maria Mastrangelo
A segregating population of 136 recombinant inbred lines derived from a cross between the durum wheat cv. "Simeto" and the T. dicoccum accession "Molise Colli" was grown in soil and evaluated for a number of shoot and root morphological traits. A total of 17 quantitative trait loci (QTL) were identified for shoot dry weight, number of culms, and plant height and for root dry weight, volume, length, surface area, and number of forks and tips, on chromosomes 1B, 2A, 3A, 4B, 5B, 6A, 6B, and 7B. LODs were 2.1 to 21...
2017: International Journal of Genomics
https://www.readbyqxmd.com/read/28833436/fast-3d-magnetic-resonance-fingerprinting-for-a-whole-brain-coverage
#7
Dan Ma, Yun Jiang, Yong Chen, Debra McGivney, Bhairav Mehta, Vikas Gulani, Mark Griswold
PURPOSE: The purpose of this study was to accelerate the acquisition and reconstruction time of 3D magnetic resonance fingerprinting scans. METHODS: A 3D magnetic resonance fingerprinting scan was accelerated by using a single-shot spiral trajectory with an undersampling factor of 48 in the x-y plane, and an interleaved sampling pattern with an undersampling factor of 3 through plane. Further acceleration came from reducing the waiting time between neighboring partitions...
August 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28829299/electrical-properties-tomography-based-on-b1-maps-in-mri-principles-applications-and-challenges
#8
Jiaen Liu, Yicun Wang, Ulrich Katscher, Bin He
OBJECTIVE: The purpose is to provide a comprehensive review of the electrical properties tomography (EPT) technique, which was introduced to image the electrical properties (EPs) of tissue noninvasively by exploiting the measured B1 field data of MRI. METHODS: We reviewed the principle of EPT, reconstruction methods, biomedical applications such as tumor imaging, and existing challenges. As a key application of EPT, the estimation of specific absorption rate (SAR) due to MRI was discussed in the background of elevated risk of tissue heating at high field...
August 21, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28777496/t2-mapping-with-magnetization-prepared-3d-tse-based-on-a-modified-bir-4%C3%A2-t2-preparation
#9
Dominik Weidlich, Sarah Schlaeger, Hendrik Kooijman, Peter Börnert, Jan S Kirschke, Ernst J Rummeny, Axel Haase, Dimitrios C Karampinos
The purpose of this work was to investigate the performance of the modified BIR-4 T2 preparation for T2 mapping and propose a method to remove T2 quantification errors in the presence of large B1 and B0 offsets. The theoretical investigation of the magnetization evolution during the T2 preparation in the presence of B1 and B0 offsets showed deviations from a mono-exponential T2 decay (two parameter fit). A three parameter fit was used to improve T2 accuracy. Furthermore, a two parameter fit with an additional saturation preparation scan was proposed to improve T2 accuracy and precision...
August 4, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28767360/software-toolbox-for-low-frequency-conductivity-and-current-density-imaging-using-mri
#10
Saurav Z K Sajib, Nitish Katoch, Hyung Joong Kim, Oh In Kwon, Eung Je Woo
OBJECTIVE: Low-frequency conductivity and current density imaging using MRI includes magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DT-MREIT), conductivity tensor imaging (CTI), and magnetic resonance current density imaging (MRCDI). MRCDI and MREIT provide current density and isotropic conductivity images, respectively, using current-injection phase MRI techniques. DT-MREIT produces anisotropic conductivity tensor images by incorporating diffusion weighted MRI into MREIT...
July 27, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28635034/modular-transmit-receive-arrays-using-very-high-permittivity-dielectric-resonator-antennas
#11
Thomas P A O'Reilly, Thomas Ruytenberg, Andrew G Webb
PURPOSE: Dielectric resonator antenna (DRAs) are compact structures that exhibit low coupling between adjacent elements and therefore can be used as MRI transmit arrays. In this study, we use very high permittivity materials to construct modular flexible transceive arrays of a variable numbers of elements for operation at 7T. METHODS: DRAs were constructed using rectangular blocks of ceramic (lead zirconate titanate, εr  = 1070) with the transverse electric (TE)01 mode tuned to 298 MHz...
June 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28632688/high-quality-3-dimensional-1h-magnetic-resonance-spectroscopic-imaging-of-the-prostate-without-endorectal-receive-coil-using-a-semi-laser-sequence
#12
Nassim Tayari, Isabell K Steinseifer, Kirsten M Selnæs, Tone F Bathen, Marnix C Maas, Arend Heerschap
OBJECTIVES: Inclusion of 3-dimensional H magnetic resonance spectroscopic imaging (3D-H-MRSI) in routine multiparametric MRI of the prostate requires good quality spectra and easy interpretable metabolite maps of the whole organ obtained without endorectal coil in clinically feasible acquisition times. We evaluated if a semi-LASER pulse sequence with gradient offset independent adiabaticity refocusing pulses (GOIA-sLASER) for volume selection can meet these requirements. MATERIALS AND METHODS: Thirteen patients with suspicion of prostate cancer and 1 patient known to have prostate cancer were examined at 3 T with a multichannel body-receive coil...
June 19, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28602814/quantitative-in-vivo-t2-mapping-using-fast-spin-echo-techniques-a-linear-correction-procedure
#13
Ulrike Nöth, Manoj Shrestha, Jan-Rüdiger Schüre, Ralf Deichmann
A method is presented for correcting the effects of stimulated and indirect echoes on quantitative T2 mapping data acquired with multiple spin echo techniques, such as turbo spin echo. In contrast to similar correction techniques proposed in the literature, the method does not require a priori knowledge of the radio frequency (RF) pulse profiles. In a first step, for the T2 mapping protocol under investigation, signal decay curves S(TE) are simulated for a range of different RF pulse profiles. The actual signal decay S(TE) is then measured on a phantom with known T2, so the approximate RF pulse profiles can be derived via comparison with the simulated decay curves...
June 9, 2017: NeuroImage
https://www.readbyqxmd.com/read/28590565/three-dimensional-mr-reconstruction-of-high-contrast-magnetic-susceptibility-by-the-variational-born-iterative-method-based-on-the-magnetic-field-volume-integral-equation
#14
Shengnan Li, Ronghan Hong, Na Liu, Jianhua Zhang, Lin Chen, Youyu Zhang, Zhiru Yu, Qing Huo Liu
PURPOSE: To provide high-quality and high-contrast magnetic susceptibility mapping, a 3D MR reconstruction method for magnetic susceptibility based on the magnetic field volume integral equation with the variational Born iterative method (VBIM) is developed. METHODS: Three-dimensional magnetic susceptibility is reconstructed from the positive rotating magnetic field component H1+ of the radiofrequency field acquired by B1 mapping. The stabilized biconjugate gradient fast Fourier transform (BCGS-FFT) method is implemented in the forward problem to solve for the magnetic field, and the conjugate gradient fast Fourier transform method is implemented in the inverse problem to reconstruct the magnetic susceptibility distribution...
June 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28556386/simple-modification-of-arm-position-improves-b1-and-signal-homogeneity-in-the-thoracolumbar-spine-at-3t
#15
Kinya Ishizaka, Kohsuke Kudo, Kuniaki Harada, Toru Shirai, Taro Fujiwara, Suzuko Aoike, Sayaka Takamori, Hiroki Shirato
PURPOSE: To evaluate the homogeneity of the radiofrequency magnetic field (B1(+) ) and signal intensity using different arm positions during 3T thoracolumbar spinal imaging. MATERIALS AND METHODS: Twenty volunteers were scanned with a four-channel radiofrequency (RF) transmit coil at 3T, with arms on the bed (conventional), arms elevated by 100 mm (arm lift), or with the arms-up position (elevated arm). Axial B1(+) maps and sagittal T1 -weighted image (T1 WI)-performed RF shimming were obtained for each arm position...
May 26, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28508476/magnetic-resonance-electrical-properties-tomography-for-small-anomalies-using-boundary-conditions-a-simulation-study
#16
Joonsung Lee, Narae Choi, Jin Keun Seo, Dong-Hyun Kim
PURPOSE: Magnetic resonance electrical property tomography (MREPT) is an emerging imaging modality using measured B1 maps from magnetic resonance imaging (MRI) to measure a distribution of electric conductivity and permittivity of the subject at the Larmor frequency. Conventional MREPT approaches at single transmit channel system using the Helmholtz equation rely on an assumption that conductivity and permittivity of the subject are locally homogeneous. For small tissue structures and tissue boundaries, in which the assumption of locally homogeneous conductivity and permittivity does not hold, the reconstructed conductivity values deviated from the actual values, so called "Boundary Artifacts...
May 16, 2017: Medical Physics
https://www.readbyqxmd.com/read/28465440/high-density-lipoprotein-receptor-scarb1-is-required-for-carotenoid-coloration-in-birds
#17
Matthew B Toomey, Ricardo J Lopes, Pedro M Araújo, James D Johnson, Małgorzata A Gazda, Sandra Afonso, Paulo G Mota, Rebecca E Koch, Geoffrey E Hill, Joseph C Corbo, Miguel Carneiro
Yellow, orange, and red coloration is a fundamental aspect of avian diversity and serves as an important signal in mate choice and aggressive interactions. This coloration is often produced through the deposition of diet-derived carotenoid pigments, yet the mechanisms of carotenoid uptake and transport are not well-understood. The white recessive breed of the common canary (Serinus canaria), which carries an autosomal recessive mutation that renders its plumage pure white, provides a unique opportunity to investigate mechanisms of carotenoid coloration...
May 16, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28437453/three-dominant-awnless-genes-in-common-wheat-fine-mapping-interaction-and-contribution-to-diversity-in-awn-shape-and-length
#18
Motohiro Yoshioka, Julio C M Iehisa, Ryoko Ohno, Tatsuro Kimura, Hiroyuki Enoki, Satoru Nishimura, Shuhei Nasuda, Shigeo Takumi
The awn is a long needle-like structure formed at the tip of the lemma in the florets of some grass species. It plays a role in seed dispersal and protection against animals, and can contribute to the photosynthetic activity of spikes. Three main dominant inhibitors of awn development (Hd, B1 and B2) are known in hexaploid wheat, but the causal genes have not been cloned yet and a genetic association with awn length diversity has been found only for the B1 allele. To analyze the prevalence of these three awning inhibitors, we attempted to predict the genotypes of 189 hexaploid wheat varieties collected worldwide using markers tightly linked to these loci...
2017: PloS One
https://www.readbyqxmd.com/read/28431009/artefact-free-late-gadolinium-enhancement-imaging-in-patients-with-implanted-cardiac-devices-using-a-modified-broadband-sequence-current-strategies-and-results-from-a-real-world-patient-cohort
#19
Sebastian Hilbert, Alexander Weber, Kay Nehrke, Peter Börnert, Bernhard Schnackenburg, Sabrina Oebel, Ricardo Spampinato, Cathleen Rogge, Sergio Richter, Gerhard Hindricks, Ingo Paetsch, Cosima Jahnke
Aims: Cardiac magnetic resonance (CMR) imaging in patients with implanted cardiac devices is often limited by device-related imaging artefacts. Limitations can potentially be overcome by employing a broadband late gadolinium enhancement (LGE)-CMR imaging technique. The purpose of this study was to investigate the relationship between implanted cardiac devices and the optimal frequency offset on broadband LGE-CMR imaging to increase the artefact-free visibility of myocardial segments. Methods and results: A phantom study was performed to characterize magnetic field disturbances related to 15 different cardiac devices...
April 18, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28424353/constrained-release-of-lamina-associated-enhancers-and-genes-from-the-nuclear-envelope-during-t-cell-activation-facilitates-their-association-in-chromosome-compartments
#20
Michael I Robson, Jose I de Las Heras, Rafal Czapiewski, Aishwarya Sivakumar, Alastair R W Kerr, Eric C Schirmer
The 3D organization of the genome changes concomitantly with expression changes during hematopoiesis and immune activation. Studies have focused either on lamina-associated domains (LADs) or on topologically associated domains (TADs), defined by preferential local chromatin interactions, and chromosome compartments, defined as higher-order interactions between TADs sharing functionally similar states. However, few studies have investigated how these affect one another. To address this, we mapped LADs using Lamin B1-DamID during Jurkat T-cell activation, finding significant genome reorganization at the nuclear periphery dominated by release of loci frequently important for T-cell function...
July 2017: Genome Research
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