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Quantitative susceptibility mapping

Yuyao Zhang, Hongjiang Wei, Matthew J Cronin, Naying He, Fuhua Yan, Chunlei Liu
Longitudinal brain atlases play an important role in the study of human brain development and cognition. Existing atlases are mainly based on anatomical features derived from T1-and T2-weighted MRI. A 4D developmental quantitative susceptibility mapping (QSM) atlas may facilitate the estimation of age-related iron changes in deep gray matter nuclei and myelin changes in white matter. To this end, group-wise co-registered QSM templates were generated over various age intervals from age 1-83 years old. Registration was achieved by combining both T1-weighted and QSM images...
January 8, 2018: NeuroImage
Carlos Milovic, Berkin Bilgic, Bo Zhao, Julio Acosta-Cabronero, Cristian Tejos
PURPOSE: Quantitative susceptibility mapping can be performed through the minimization of a function consisting of data fidelity and regularization terms. For data consistency, a Gaussian-phase noise distribution is often assumed, which breaks down when the signal-to-noise ratio is low. A previously proposed alternative is to use a nonlinear data fidelity term, which reduces streaking artifacts, mitigates noise amplification, and results in more accurate susceptibility estimates. We hereby present a novel algorithm that solves the nonlinear functional while achieving computation speeds comparable to those for a linear formulation...
January 10, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Sais-Beul Lee, Yeon-Jae Hur, Jun-Hyeon Cho, Jong-Hee Lee, Tae-Heon Kim, Soo-Min Cho, You-Chun Song, Young-Su Seo, Jungkwan Lee, Tae-Sung Kim, Yong-Jin Park, Myung-Kyu Oh, Dong-Soo Park
BACKGROUND: Bakanae or foot rot disease is a prominent disease of rice caused by Gibberella fujikuroi. This disease may infect rice plants from the pre-emergence stage to the mature stage. In recent years, raising rice seedlings in seed boxes for mechanical transplanting has increased the incidence of many seedling diseases; only a few rice varieties have been reported to exhibit resistance to bakanae disease. In this study, we attempted to identify quantitative trait loci (QTLs) conferring bakanae disease resistance from the highly resistant japonica variety Wonseadaesoo...
January 10, 2018: Rice
Xing Lu, Yajun Ma, Eric Y Chang, Qun He, Adam Searleman, Annette von Drygalski, Jiang Du
PURPOSE: To evaluate the echo dependence of 3D ultrashort echo time (TE) quantitative susceptibility mapping (3D UTE-QSM) and effective transverse relaxation rate ( R2*) measurement in the setting of high concentrations of iron oxide nanoparticles. METHODS: A phantom study with iron concentrations ranging from 2 to 22 mM was performed using a 3D UTE Cones sequence. Simultaneous QSM processing with morphology-enabled dipole inversion (MEDI) and R2* single exponential fitting was conducted offline with the acquired 3D UTE data...
January 4, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Junyan Feng, Meinan Wang, Deven R See, Shiaoman Chao, You-Liang Zheng, Xianming Chen
Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of wheat worldwide. Exploring new resistance genes is essential for breeding resistant wheat cultivars. PI 182103, a spring wheat landrace originally from Pakistan, has shown a high level of resistance to stripe rust in fields for many years, but genes for resistance to stripe rust in the variety have not been studied. To map the resistance gene(s) in PI 182103, 185 recombinant inbred lines (RILs) were developed from a cross with Avocet Susceptible (AvS)...
January 5, 2018: Phytopathology
Jansen Rodrigo Pereira Santos, Arsenio Daniel Ndeve, Bao-Lam Huynh, William Charles Matthews, Philip Alan Roberts
Cowpea is one of the most important food and forage legumes in drier regions of the tropics and subtropics. However, cowpea yield worldwide is markedly below the known potential due to abiotic and biotic stresses, including parasitism by root-knot nematodes (Meloidogyne spp., RKN). Two resistance genes with dominant effect, Rk and Rk2, have been reported to provide resistance against RKN in cowpea. Despite their description and use in breeding for resistance to RKN and particularly genetic mapping of the Rk locus, the exact genes conferring resistance to RKN remain unknown...
2018: PloS One
Weihsueh A Chiu, Ivan Rusyn
Characterizing population variability, including identifying susceptible populations and quantifying their increased susceptibility, is an important aspect of chemical risk assessment, but one that is challenging with traditional experimental models and risk assessment methods. New models and methods to address population variability can be used to advance the human health assessments of chemicals in three key areas. First, with respect to hazard identification, evaluating toxicity using population-based in vitro and in vivo models can potentially reduce both false positive and false negative signals...
January 3, 2018: Mammalian Genome: Official Journal of the International Mammalian Genome Society
I Verrastro, K Tveen-Jensen, C M Spickett, A R Pitt
Oxidation by reactive species can cause changes in protein function and affect cell signaling pathways. Phosphatase and tensin homolog (PTEN) is a negative regulator of the PI3K/AKT pathway and is known to be inhibited by oxidation, but its oxidation by the myeloperoxidase-derived oxidant hypochlorous acid (HOCl) has not previously been investigated. PTEN-GST was treated with HOCl:protein ratios from 15:1 to 300:1. Decreases in PTEN phosphatase activity were observed at treatment ratios of 60:1 and higher, which correlated with the loss of the intact protein band and appearance of high molecular weight aggregates in SDS-PAGE...
January 3, 2018: Free Radical Research
Qifang Yang, Lina Zhou, Chen Liu, Daihong Liu, Yang Zhang, Chang Li, Yongning Shang, Xin Wei, Chuanming Li, Jian Wang
This study was performed to investigate iron deposition in the brain of type 2 diabetes mellitus (T2DM) patients using quantitative susceptibility mapping (QSM) and the associated cognitive impairments. Sixty patients diagnosed with T2DM were subjected to neuropsychological tests to determine their cognitive status, and the results were used to subdivide the patients into a T2DM without mild cognitive impairment (MCI) group (n = 30) and a T2DM with MCI group (n = 30). All patients underwent high-resolution susceptibility-weighted imaging, and data processing was performed using SMART (Susceptibility Mapping and Phase Artifacts Removal Toolbox) software...
January 3, 2018: Brain Imaging and Behavior
Mark W Jones, Bryan W Penning, Tiffany M Jamann, Jeff C Glaubitz, Cinta Romay, Edward S Buckler, Margaret Redinbaugh
The recent rapid emergence of maize lethal necrosis (MLN), caused by coinfection of maize with maize chlorotic mottle virus (MCMV) and a second virus usually from the family Potyviridae, is causing extensive losses for farmers in East Africa, Southeast Asia and South America. Although the genetic basis of resistance to potyviruses is well understood in maize, little was known about resistance to MCMV. The responses of five maize inbred lines (KS23-5, KS23-6, N211, DR and Oh1VI) to inoculation with MCMV, sugarcane mosaic virus and MLN were characterized...
December 29, 2017: Phytopathology
Jeremías Enrique Zubrzycki, Carla Andrea Maringolo, Carla Valeria Filippi, Facundo José Quiróz, Verónica Nishinakamasu, Andrea Fabiana Puebla, Julio A Di Rienzo, Alberto Escande, Verónica Viviana Lia, Ruth Amalia Heinz, Horacio Esteban Hopp, Gerardo D L Cervigni, Norma Beatriz Paniego
Sclerotinia Head Rot (SHR), a disease caused by Sclerotinia sclerotiorum, is one of the most limiting factors in sunflower production. In this study, we identified genomic loci associated with resistance to SHR to support the development of assisted breeding strategies. We genotyped 114 Recombinant Inbred Lines (RILs) along with their parental lines (PAC2 -partially resistant-and RHA266 -susceptible-) by using a 384 single nucleotide polymorphism (SNP) Illumina Oligo Pool Assay to saturate a sunflower genetic map...
2017: PloS One
Serena Monti, Pasquale Borrelli, Enrico Tedeschi, Sirio Cocozza, Giuseppe Palma
Susceptibility Weighted Imaging (SWI) is a common MRI technique that exploits the magnetic susceptibility differences between the tissues to provide valuable image contrasts, both in research and clinical contexts. However, despite its increased clinical use, SWI is not intrinsically suitable for quantitation purposes. Conversely, quantitative Magnetic Resonance Imaging (qMRI) provides a way to disentangle the sources of common MR image contrasts (e.g. proton density, T1, etc.) and to measure physical parameters intrinsically related to tissue microstructure...
2017: PloS One
Nabin Bhusal, Ashok Kumar Sarial, Pradeep Sharma, Sindhu Sareen
The current perspective of increasing global temperature makes heat stress as a major threat to wheat production worldwide. In order to identify quantitative trait loci (QTLs) associated with heat tolerance, 251 recombinant inbred lines (RILs) derived from a cross between HD2808 (heat tolerant) and HUW510 (heat susceptible) were evaluated under timely sown (normal) and late sown (heat stress) conditions for two consecutive crop seasons; 2013-14 and 2014-15. Grain yield (GY) and its components namely, grain weight/spike (GWS), grain number/spike (GNS), thousand grain weight (TGW), grain filling rate (GFR) and grain filling duration (GFD) were recorded for both conditions and years...
2017: PloS One
Arnold M Evia, Aikaterini Kotrotsou, Ashish A Tamhane, Robert J Dawe, Alifiya Kapasi, Sue E Leurgans, Julie A Schneider, David A Bennett, Konstantinos Arfanakis
Ex-vivo brain quantitative susceptibility mapping (QSM) allows investigation of brain characteristics at essentially the same point in time as histopathologic examination, and therefore has the potential to become an important tool for determining the role of QSM as a diagnostic and monitoring tool of age-related neuropathologies. In order to be able to translate the ex-vivo QSM findings to in-vivo, it is crucial to understand the effects of death and chemical fixation on brain magnetic susceptibility measurements collected ex-vivo...
2017: PloS One
Chao Chai, Saifeng Liu, Linlin Fan, Lei Liu, Jinping Li, Chao Zuo, Tianyi Qian, E Mark Haacke, Wen Shen, Shuang Xia
Cerebral venous oxygen saturation (SvO2) is an important indicator of brain function. There was debate about lower cerebral oxygen metabolism in hemodialysis patients and there were no reports about the changes of deep regional cerebral SvO2 in hemodialysis patients. In this study, we aim to explore the deep regional cerebral SvO2 from straight sinus using quantitative susceptibility mapping (QSM) and the correlation with clinical risk factors and neuropsychiatric testing. 52 hemodialysis patients and 54 age-and gender-matched healthy controls were enrolled...
December 16, 2017: Metabolic Brain Disease
Y Yao, T D Nguyen, S Pandya, Y Zhang, S Hurtado Rúa, I Kovanlikaya, A Kuceyeski, Z Liu, Y Wang, S A Gauthier
BACKGROUND AND PURPOSE: A hyperintense rim on susceptibility in chronic MS lesions is consistent with iron deposition, and the purpose of this study was to quantify iron-related myelin damage within these lesions as compared with those without rim. MATERIALS AND METHODS: Forty-six patients had 2 longitudinal quantitative susceptibility mapping with automatic zero reference scans with a mean interval of 28.9 ± 11.4 months. Myelin water fraction mapping by using fast acquisition with spiral trajectory and T2 prep was obtained at the second time point to measure myelin damage...
December 14, 2017: AJNR. American Journal of Neuroradiology
Hyeonso Ji, Tae-Ho Kim, Gang-Seob Lee, Hyun-Ju Kang, Seung-Bum Lee, Seok Cheol Suh, Song Lim Kim, Inchan Choi, Jeongho Baek, Kyung-Hwan Kim
Bakanae disease (BD) has emerged as a serious threat in almost all rice cultivation regions worldwide. Nampyeong is a Korean japonica rice variety known to be resistant to BD. In this study, quantitative trait locus (QTL) mapping was performed with F2 and F3 plants derived from a cross between the Nampyeong variety and a susceptible Korean japonica line, DongjinAD. First, resequencing of Nampyeong and DongjinAD was performed, which identified 171,035 single nucleotide polymorphisms (SNPs) between the two parental varieties...
December 11, 2017: Molecular Genetics and Genomics: MGG
Martin O Bohn, Juan J Marroquin, Sherry Flint-Garcia, Kenton Dashiell, David B Willmot, Bruce E Hibbard
Over the last 70 yr, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera (LeConte; Coleoptera: Chrysomelidae), larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Selected genotypes were mostly characterized by large root systems and superior root regrowth after root damage caused by western corn rootworm larvae. However, no hybrids claiming native (i...
December 8, 2017: Journal of Economic Entomology
Pinar Senay Özbay, Sonja Stieb, Cristina Rossi, Oliver Riesterer, Andreas Boss, Tobias Weiss, Felix Kuhn, Klaas Paul Pruessmann, Daniel Nanz
BACKGROUND AND PURPOSE: Quantitative susceptibility mapping has been previously used to differentiate lesions in patients with brain tumors. The aim of this work was to characterize the response of magnetic susceptibility differences in malignant brain tumors and surrounding edema to hyperoxic and hypercapnic respiratory challenges. METHODS: Images of malignant brain tumor patients (2 glioblastoma multiforme, 2 anaplastic astrocytoma, 1 brain metastasis) with clinical MRI exams (contrast-enhanced T1w) were acquired at 3T...
December 5, 2017: Magnetic Resonance Imaging
Aimin Wen, Malini Jayawardana, Jason Fiedler, Suraj Sapkota, Gongjun Shi, Zhao Peng, Sanzhen Liu, Frank F White, Adam J Bogdanove, Xuehui Li, Zhaohui Liu
A major gene conferring resistance to bacterial leaf streak was mapped to chromosome 5R in triticale. Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa (Xtu), is an important disease of wheat and triticale around the world. Although resistance to BLS is limited in wheat, several triticale accessions have high levels of resistance. To characterize the genetic basis of this resistance, we developed triticale mapping populations using a resistant accession (Siskiyou) and two susceptible accessions (UC38 and Villax St...
December 7, 2017: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
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