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B1 mapping

Grzegorz Bauman, Francesco Santini, Orso Pusterla, Oliver Bieri
PURPOSE: To present a technique for simultaneous mapping of T1 , T2 , and relative spin density (M0 ) in human lung using inversion recovery ultra-fast steady-state free precession (IR-ufSSFP) imaging. METHODS: Pulmonary relaxometry with IR-ufSSFP is based on an interleaved time series acquisition of 2D images acquired at 1.5T. The technique was tested in a phantom and in four healthy volunteers using breath-hold and electrocardiogram triggering. Typically, 30 transient state images were acquired in a single breath-hold within < 10 s...
October 19, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Afshin Pourmokhtarian, Charles T Driscoll, John L Campbell, Katharine Hayhoe, Anne M K Stoner
Assessments of future climate change impacts on ecosystems typically rely on multiple climate model projections, but often utilize only one downscaling approach trained on one set of observations. Here, we explore the extent to which modeled biogeochemical responses to changing climate are affected by the selection of the climate downscaling method and training observations used at the montane landscape of the Hubbard Brook Experimental Forest, New Hampshire, USA. We evaluated three downscaling methods: the delta method (or the change factor method), monthly quantile mapping (Bias Correction-Spatial Disaggregation, or BCSD), and daily quantile regression (Asynchronous Regional Regression Model, or ARRM)...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
Libao Cheng, Shuyan Li, Sainan Chen, Yan Wang, Meizhen Yu, Xuehao Chen, Liangjun Li, Jingjing Yin
The product organ (storage organ; corm) of the Chinese water chestnut has become a very popular food in Asian countries because of its unique nutritional value. Corm formation is a complex biological process, and extensive whole genome analysis of transcripts during corm development has not been carried out. In this study, four corm libraries at different developmental stages were constructed, and gene expression was identified using a high-throughput tag sequencing technique. Approximately 4.9 million tags were sequenced, and 4,371,386, 4,372,602, 4,782,494, and 5,276,540 clean tags, including 119,676, 110,701, 100,089, and 101,239 distinct tags, respectively, were obtained after removal of low-quality tags from each library...
2016: PloS One
Tiago Teixeira, Tarik Hafyane, Nikola Stikov, Cansu Akdeniz, Andreas Greiser, Matthias G Friedrich
BACKGROUND: T1 mapping based on cardiovascular magnetic resonance (CMR) is a novel approach using the magnetic relaxation T1 time as a quantitative marker for myocardial tissue composition. Various T1 mapping sequences are being used, with different strengths and weaknesses. Data comparing different sequences head to head however are sparse. METHODS: We compared three T1 mapping sequences, ShMOLLI, MOLLI and SASHA in phantoms and in a mid-ventricular slice of 40 healthy individuals (mean age 59 ± 7 years, 45 % male) with low (68 %) or moderate cardiovascular risk...
October 4, 2016: Journal of Cardiovascular Magnetic Resonance
Gen Yan, Tao Zhang, Zhuozhi Dai, Meizhi Yi, Yanlong Jia, Tingting Nie, Handi Zhang, Gang Xiao, Renhua Wu
PURPOSE: We developed a novel magnetic resonance imaging (MRI) technique based on chemical exchange saturation transfer (CEST) for GABA imaging and investigated the concentration-dependent CEST effect ofGABA in a rat model of brain tumor with blood-brain barrier (BBB) disruption. MATERIALS AND METHODS: All MRI studies were performed using a 7.0-T Agilent MRI scanner. Z-spectra for GABA were acquired at 7.0 T, 37°C, and a pH of 7.0 using varying B1 amplitudes. CEST images of phantoms with different concentrations of GABA solutions (pH, 7...
2016: PloS One
Zehua Qu, Zhengbo Qin, Xianfeng Zheng, Hui Wang, Guanxin Yao, Xianyi Zhang, Zhifeng Cui
Slow electron velocity-map imaging (SEVI) of aniline has been investigated via two-color resonant-enhanced two-photo (1+1') ionization (2C-R2PI) method. A number of vibrational frequencies in the first excited state of neutral (S1) and (2)B1 ground electronic state of cation (D0) have been accurately determined. In addition, photoelectron angular distributions (PADs) in the two-step transitions are presented and reveal a near threshold shape resonance in the ionization of aniline. The SEVI spectra taken via various S1 intermediate states provide the detailed vibrational structures of D0 state and directly deduce the accurate adiabatic ionization potential (IP) of 62,271±6cm(-1)...
September 28, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jeong Hee Yoon, Jeong Min Lee, Eunju Kim, Tomoyuki Okuaki, Joon Koo Han
Purpose To determine whether B1 inhomogeneity-corrected volumetric T1 maps of gadoxetic acid-enhanced liver magnetic resonance (MR) imaging are able to demonstrate global liver function and functional heterogeneity in patients with cirrhosis and to investigate their relationship with the development of hepatic insufficiency and decompensation. Materials and Methods This institutional review board-approved retrospective study with waiver of informed consent included 234 consecutive patients who underwent gadoxetic acid-enhanced liver MR imaging, including B1 inhomogeneity-corrected volumetric T1 mapping...
October 3, 2016: Radiology
Bing-Fang Chen
AIM: To investigate the associations of different types of pre-S deletions with hepatitis B virus (HBV) genotypes. METHODS: The sequences of the pre-S region, basal core promoter (BCP) mutation, and precore (PC) mutation were examined through direct DNA sequencing or clonal analysis and sequencing in 273 HBV carriers, namely 55 asymptomatic carriers, 55 carriers with chronic hepatitis (CH), 55 with liver cirrhosis (LC), 53 with liver cirrhotic hepatocellular carcinoma (LC-HCC), and 55 with noncirrhotic HCC...
September 21, 2016: World Journal of Gastroenterology: WJG
Noemie Prat, Camille Guilbert, Ursa Prah, Elisabeth Wachter, Barbara Steiner, Thierry Langin, Olivier Robert, Hermann Buerstmayr
The QTL Fhb1 was successfully introgressed and validated in three durum wheat populations. The novel germplasm and the QTL detected will support improvement of Fusarium resistance in durum wheat. Durum wheat (Triticum durum Desf.) is particularly susceptible to Fusarium head blight (FHB) and breeding for resistance is hampered by limited genetic variation within this species. To date, resistant sources are mainly available in a few wild relative tetraploid wheat accessions. In this study, the effect of the well-known hexaploid wheat (Triticum aestivum L...
September 23, 2016: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Jihye Jang, Steven Bellm, Sébastien Roujol, Tamer A Basha, Maryam Nezafat, Shingo Kato, Sebastian Weingärtner, Reza Nezafat
Cardiac T1 mapping allows non-invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel-wise fitting of the images acquired using balanced steady-state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts. A gradient echo (GRE) imaging sequence has been used for myocardial T1 mapping; however, its use has been limited to higher magnetic field to compensate for the lower signal-to-noise ratio (SNR) of GRE versus SSFP imaging...
October 2016: NMR in Biomedicine
M H Abdulla, M Duff, H Swanton, E J Johns
AIM: This study investigated the effect of renal bradykinin B1 and B2 receptor blockade on the high- and low-pressure baroreceptor reflex regulation of renal sympathetic nerve activity (RSNA) in rats with cisplatin-induced renal failure. METHODS: Cisplatin (5 mg/kg) or saline was given intraperitoneally 4 days prior to study. Following chloralose/urethane anaesthesia, rats were prepared for measurement of mean arterial pressure (MAP), heart rate and RSNA and received intrarenal infusions of either Lys-[des-Arg(9) , Leu(8) ]-bradykinin (LBK), a bradykinin B1 receptor blocker, or bradyzide (BZ), a bradykinin B2 receptor blocker...
November 2016: Acta Physiologica
Wubin Wang, Meifeng Liu, Yufeng Wang, Xuliang Li, Shixuan Cheng, Liping Shu, Zheping Yu, Jiejie Kong, Tuanjie Zhao, Junyi Gai
Annual wild soybean (Glycine soja Sieb. and Zucc.), the wild progenitor of the cultivated soybean [Glycine max (L.) Merr.], is valuable for improving the later. The construction of a linkage map is crucial for studying the genetic differentiation between these species, but marker density is the main factor limiting the accuracy of such a map. Recent advances in next-generation sequencing technologies allow for the generation of high-density linkage maps. Here, two sets of inter-specific recombinant inbred line populations, named NJIRNP and NJIR4P, composed of 284 and 161 lines, respectively, were generated from the same wild male parent, PI 342618B, and genotyped by restriction-site-associated DNA sequencing...
2016: Frontiers in Plant Science
Sebastian Weingärtner, Fabian Zimmer, Gregory J Metzger, Kâmil Uğurbil, Pierre-Francois Van de Moortele, Mehmet Akçakaya
PURPOSE: To develop and evaluate a robust motion-insensitive Bloch-Siegert shift based B1+ mapping method in the heart. METHODS: Cardiac Bloch-Siegert B1+ mapping was performed with interleaved positive and negative off-resonance shifts and diastolic spoiled gradient echo imaging in 12 heartbeats. Numerical simulations were performed to study the impact of respiratory motion. The method was compared with three-dimensional (3D) actual flip angle imaging (AFI) and two-dimensional (2D) saturated double angle method (SDAM) in phantom scans...
September 7, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
William T Clarke, Matthew D Robson, Stefan Neubauer, Christopher T Rodgers
PURPOSE: We present a new Bloch-Siegert four Angle Saturation Transfer (BOAST) method for measuring the creatine kinase (CK) first-order effective rate constant kf in human myocardium at 7 tesla (T). BOAST combines a variant of the four-angle saturation transfer (FAST) method using amplitude-modulated radiofrequency pulses, phosphorus Bloch-Siegert B1+-mapping to determine the per-voxel flip angles, and nonlinear fitting to Bloch simulations for postprocessing. METHODS: Optimal flip angles and repetition time parameters were determined from Monte Carlo simulations...
August 31, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Aurélien Massire, Manuel Taso, Pierre Besson, Maxime Guye, Jean-Philippe Ranjeva, Virginie Callot
Quantitative MRI techniques have the potential to characterize spinal cord tissue impairments occurring in various pathologies, from both microstructural and functional perspectives. By enabling very high image resolution and enhanced tissue contrast, ultra-high field imaging may offer further opportunities for such characterization. In this study, a multi-parametric high-resolution quantitative MRI protocol is proposed to characterize in vivo the human cervical spinal cord at 7T. Multi-parametric quantitative MRI acquizitions including T1, T2(*) relaxometry mapping and axial diffusion MRI were performed on ten healthy volunteers with a whole-body 7T system using a commercial prototype coil-array dedicated to cervical spinal cord imaging...
August 26, 2016: NeuroImage
Kejia Cai, Rong-Wen Tain, Xiaohong Joe Zhou, Frederick C Damen, Alessandro M Scotti, Hari Hariharan, Harish Poptani, Ravinder Reddy
PURPOSE: Creatine (Cr) is a major metabolite in the bioenergetic system. Measurement of Cr using conventional MR spectroscopy (MRS) suffers from low spatial resolution and relatively long acquisition times. Creatine chemical exchange saturation transfer (CrCEST) magnetic resonance imaging (MRI) is an emerging molecular imaging method for tissue Cr measurements. Our previous study showed that the CrCEST contrast, obtained through multicomponent Z-spectral fitting, was lower in tumors compared to normal brain, which further reduced with tumor progression...
August 19, 2016: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
Asemeh Miraghazadeh, Peng Zhang, Carol Harding, Shek Hossain, Matthew Hayden, Debbie Wong, Wolfgang Spielmeyer, Peter M Chandler
Many deletions of the wheat Della ( Rht - B1 ) gene and its flanking regions were isolated in a simple phenotypic screen, and characterised by modified analysis of SNP hybridisation data and cytogenetics. In a dwarf wheat suppressor screen, many tall 'revertants' were isolated following mutagenesis of a severely dwarfed (Rht-B1c) hexaploid wheat. About 150 lines were identified as putative deletions of Rht-B1c, based on the PCR analysis. Southern blot hybridisation established that most of them lacked the Rht-B1 gene, but retained the homoeologues Rht-A1 and Rht-D1...
August 18, 2016: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Novena A Rangwala, Isabel Dregely, Holden H Wu, Kyunghyun Sung
PURPOSE: To optimize and evaluate the reference region variable flip angle (RR-VFA) technique for simultaneous B1+ and T1 mapping of the prostate at 3 Tesla (T). MATERIALS AND METHODS: The fat region surrounding the prostate was first identified using a fractional fat segmentation constant (tF ) and a signal fat-fraction threshold (rF ), and the relative flip angle (FA) was characterized using an effective fat T1 (T1f ) within the fat region. Optimal values of tF , rF , and T1f were chosen by comparing relative FA maps using RR-VFA (ARR-VFA ) with a reference relative FA maps (AREF ) in the surrounding fat and evaluating interpolation errors within the prostate...
August 17, 2016: Journal of Magnetic Resonance Imaging: JMRI
Wan-Chen Tsai, Kuo-Jang Kao, Kai-Ming Chang, Chen-Fang Hung, Qing Yang, Chien-Yuan E Lin, Chii-Ming Chen
Purpose To prospectively quantify the effect of T1 estimation in fat by B1 correction in breast magnetic resonance (MR) imaging at 1.5 T and to examine the subsequent quantitative dynamic contrast material-enhanced parameters in breast cancer with and without B1 correction. Materials and Methods This study had institutional review board approval, and informed consent was obtained from 72 patients with breast cancer before breast MR imaging studies were performed between January and July 2015. B1(+) field and variable flip angle (FA) mapping were included in the dynamic contrast-enhanced breast MR imaging protocol with a 1...
August 1, 2016: Radiology
Auchithya Dissanayaka, Tito O Rodriguez, Shaokang Di, Fan Yan, Stephen M Githiri, Felipe Rojas Rodas, Jun Abe, Ryoji Takahashi
Time to flowering and maturity in soybean is controlled by loci E1 to E5, and E7 to E9. These loci were assigned to molecular linkage groups (MLGs) except for E5. This study was conducted to map the E5 locus using F2 populations expected to segregate for E5. F2 populations were subjected to quantitative trait locus (QTL) analysis for days to flowering (DF) and maturity (DM). In Harosoy-E5 × Clark-e2 population, QTLs for DF and DM were found at a similar position with E2. In Harosoy × Clark-e2E5 population, QTLs for DF and DM were found in MLG D1a and B1, respectively...
June 2016: Breeding Science
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