Both enantiomers of functionalized Hajos-Parrish ketone (HPK) analogs were prepared with excellent diastereoselectivities and enantioselectivities using the same chiral catalyst under two slightly different conditions. In condition A, dioxane was used as the solvent with 3 equivalents of water. In condition B, acetonitrile was used as the solvent with 30 equivalents of water, followed by epimerization with a base in a one-pot.
View Article and Find Full Text PDFThis study aimed to investigate the performance of a fine-tuned large language model (LLM) in extracting patients on pretreatment for lung cancer from picture archiving and communication systems (PACS) and comparing it with that of radiologists. Patients whose radiological reports contained the term lung cancer (3111 for training, 124 for validation, and 288 for test) were included in this retrospective study. Based on clinical indication and diagnosis sections of the radiological report (used as input data), they were classified into four groups (used as reference data): group 0 (no lung cancer), group 1 (pretreatment lung cancer present), group 2 (after treatment for lung cancer), and group 3 (planning radiation therapy).
View Article and Find Full Text PDFPurpose: The quality and bias of annotations by annotators (e.g., radiologists) affect the performance changes in computer-aided detection (CAD) software using machine learning.
View Article and Find Full Text PDFBackground COVID-19 vaccination-related axillary lymphadenopathy has become an important problem in cancer imaging. Data are needed to update or support imaging guidelines for conducting appropriate follow-up. Purpose To investigate the prevalence, predisposing factors, and MRI characteristics of COVID-19 vaccination-related axillary lymphadenopathy.
View Article and Find Full Text PDFFlow reactions using an immobilized diphenylprolinol alkyl ether catalyst 2 were investigated in three reactions of α,β-unsaturated aldehydes and nitroalkanes such as nitromethane 3, nitroethanol 10, and nitroalkane 11, bearing two carbonyl groups. Whereas reactions using the corresponding monomer catalyst diphenylprolinol silyl ether 1 were slow, fast reactions were found with the immobilized polymer catalyst 2 in a batch system, and the latter was then applied to a flow system. In the Michael reaction of nitromethane 3, the polymer catalyst showed high reactivity in the initial 30 h and then decreased gradually.
View Article and Find Full Text PDFBackground: Diffusion-weighted imaging performed shortly after brain injury has been shown to facilitate visualization of acute corticospinal tract injury known as "pre-Wallerian degeneration."
Objective: The aim of this study was to determine whether diffusion restriction in the corticospinal tract and corpus callosum occurs within the first 2 weeks after birth in neonates with neonatal hypoxic-ischemic encephalopathy.
Materials And Methods: We enrolled a consecutive series of 66 infants diagnosed with hypoxic-ischemic encephalopathy who underwent MRI.
ACTA2-related vasculopathy is an autosomal dominant genetic disorder characterized by aortic aneurysms and dissection, and limb artery lesions are rare. We report a case of transcatheter arterial embolization for a pseudoaneurysm of a deep femoral artery in a patient with presumptive ACTA2-related vasculopathy. A 58-year-old woman was presumed to have an mutation based on her history of aortic diseases and family history of mutations.
View Article and Find Full Text PDFEnantiodivergent one-pot synthesis of biaryls was developed using a catalytic amount of a single chiral source. A domino organocatalyst-mediated enantioselective Michael reaction and aldol condensation provided centrally chiral dihydronaphthalenes with excellent enantioselectivity, from which an enantiodivergent chirality conversion from central-to-axial chirality was achieved. Both enantiomers of biaryls were obtained with excellent enantioselectivity.
View Article and Find Full Text PDFSubstituted 9-methyldecalin derivatives containing an all carbon quaternary chiral center were synthesized with excellent enantioselectivity via an organocatalyst-mediated domino reaction. The first reaction is a diphenylprolinol silyl ether-mediated Michael reaction, and the second reaction is an intramolecular aldol reaction. The enantiomerically pure catalyst is involved in both reactions.
View Article and Find Full Text PDFBackground: Unsupervised learning can discover various unseen abnormalities, relying on large-scale unannotated medical images of healthy subjects. Towards this, unsupervised methods reconstruct a 2D/3D single medical image to detect outliers either in the learned feature space or from high reconstruction loss. However, without considering continuity between multiple adjacent slices, they cannot directly discriminate diseases composed of the accumulation of subtle anatomical anomalies, such as Alzheimer's disease (AD).
View Article and Find Full Text PDFIntroduction: Oscillating gradient spin-echo (OGSE) sequences enable acquisitions with shorter diffusion times. There is growing interest in the effect of diffusion time on apparent diffusion coefficient (ADC) values in patients with cancer. However, little evidence exists regarding its usefulness for differentiating between high-grade and low-grade brain tumors.
View Article and Find Full Text PDFInvited for the cover of this issue is the group of Yujiro Hayashi at the University of Tohoku University. The image depicts the spinning motion of a figure skater, which illustrates the transformation of the chiral information investigated in this work. Read the full text of the article at 10.
View Article and Find Full Text PDFSingle nucleotide polymorphisms in Tolloid-like 1 (TLL1) and the expression of are known to be closely related to hepatocarcinogenesis after hepatitis C virus elimination or liver fibrosis in patients with nonalcoholic fatty liver disease. TLL1 is a type of matrix metalloprotease and has two isoforms in humans, with the short isoform showing higher activity. However, the functional role of TLL1 in human liver development is unknown.
View Article and Find Full Text PDFBackground: Perinatal hypoxic-ischemic encephalopathy (HIE) is a major cause of death and disability in infants. Magnetic resonance imaging (MRI) is valuable for predicting the outcome in high-risk neonates. The relationship of pontine and cerebellar injury to outcome has not been explored sufficiently.
View Article and Find Full Text PDFThe pot-economical, highly enantioselective synthesis of axially chiral biaryls was developed by using one-pot organocatalyst-mediated domino and aromatization reactions as key steps. The axial information of the precursor, which also has central chirality, was completely inverted in the final biaryls. The inversion of the axial information occurred in the conversion of the central chirality to the axial chirality of an oxidative aromatization step.
View Article and Find Full Text PDFPurpose: The most severe form of profound asphyxia in neonates is now known as "total brain injury," which forms part of the clinical spectrum of hypoxic-ischemic encephalopathy (HIE). Although the magnetic resonance (MR) imaging features of total brain injury remain to be determined, a widespread hyperintensity of the supratentorial brain, known as the "white cerebrum sign," has been reported in diffusion-weighted images (DWI).
Methods: We examined four neonates who developed severe profound asphyxia.
A three-pot synthetic method that features the use of an organocatalyst as the key step was developed for the preparation of biaryl atropisomers. The first reaction is an asymmetric domino Michael-Henry reaction catalyzed by diphenylprolinol silyl ether to afford the substituted nitrocyclohexanecarbaldehyde with four stereogenic centers and one defined configuration of a stereogenic axis with excellent enantioselectivity. Removal of the central chirality from the domino products afforded biaryl atropisomers having axial chirality with excellent enantioselectivity.
View Article and Find Full Text PDFPurpose: Flowing blood sometimes appears bright on synthetic T-weighted images, which could be misdiagnosed as a thrombus. This study aimed to investigate the frequency of hyperintensity within cerebral venous sinuses on synthetic MR images and to evaluate the influence of increasing flow rates on signal intensity using a flow phantom.
Materials And Methods: Imaging data, including synthetic and conventional MRI scans, from 22 patients were retrospectively analyzed.
Quantitative magnetic resonance imaging (MRI) with multislice, multi-echo, and multi-delay acquisition enables simultaneous quantification of R and R relaxation rates, proton density, and the B field in a single acquisition, and requires only about 6 minutes for full-head coverage. Using dedicated SyMRI software, radiologists can generate any contrast-weighted image by manipulating the acquisition parameters, including repetition time, echo time, and inversion time. Moreover, automatic brain tissue segmentation, volumetry, and myelin measurement can also be performed.
View Article and Find Full Text PDFBackground And Purpose: Synthetic FLAIR images are of lower quality than conventional FLAIR images. Here, we aimed to improve the synthetic FLAIR image quality using deep learning with pixel-by-pixel translation through conditional generative adversarial network training.
Materials And Methods: Forty patients with MS were prospectively included and scanned (3T) to acquire synthetic MR imaging and conventional FLAIR images.
Introduction: Oscillating gradient spin-echo (OGSE) sequences can shorten diffusion times by replacing the long-lasting diffusion-sensitizing gradients used in pulsed gradient spin-echo (PGSE) methods with rapidly oscillating gradients. To obtain information regarding the internal structure of choroid plexus cysts that appear hyperintense on diffusion-weighted imaging (DWI), we investigated the apparent diffusion coefficient (ADC) values acquired with a shorter diffusion time using an OGSE sequence.
Material And Methods: Twenty-seven patients with choroid plexus cysts were scanned using a 3 T magnetic resonance scanner.
AJNR Am J Neuroradiol
February 2019
Background And Purpose: The effect of gadolinium on the estimation of myelin has not been reported. The aim of the current study was to investigate the effects of gadolinium on automatic myelin and brain tissue volumetry via quantitative synthetic MR imaging.
Materials And Methods: The study included 36 patients who were referred for brain metastases screening, and quantitative synthetic MR imaging data before and after gadolinium-based contrast agent administration were analyzed retrospectively.
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