NON-CARTESIAN SELF-SUPERVISED PHYSICS-DRIVEN DEEP LEARNING RECONSTRUCTION FOR HIGHLY-ACCELERATED MULTI-ECHO SPIRAL FMRI.

Functional MRI (fMRI) is an important tool for non-invasive studies of brain function. Over the past decade, multi-echo fMRI methods that sample multiple echo times has become popular with potential to improve quantification. While these acquisitions are typically performed with Cartesian trajectories, non-Cartesian trajectories, in particular spiral acquisitions, hold promise for denser sampling of echo times.

Effect of Intermittent vs. Continuous Energy Restriction on Visceral Fat: Protocol for The Healthy Diet and Lifestyle Study 2 (HDLS2).

Obesity in the United States and Western countries represents a major health challenge associated with an increased risk of metabolic diseases, including cardiovascular disease, hypertension, diabetes, and certain cancers. Our past work revealed a more pronounced obesity-cancer link in certain ethnic groups, motivating us to develop a tailored dietary intervention called the Healthy Diet and Lifestyle 2 (HDLS2). The study protocol is described herein for this randomized six-month trial examining the effects of intermittent energy restriction (5:2 Diet) plus the Mediterranean dietary pattern (IER + MED) on visceral adipose tissue (VAT), liver fat, and metabolic biomarkers, compared to a standard MED with daily energy restriction (DER + MED), in a diverse participant group.

A comparison of pre- and post-clinical education learning preferences among medical students who elected to dissect compared to those who did not during the COVID-19 pandemic.

Anatomy instructional methods varied widely during the COVID-19 pandemic and programs are assessing innovations for retention. Learning preferences were assessed among medical students dichotomized as elective dissectors (ED) or non-dissectors (ND) during the COVID-19 partial re-opening in 2020 (preclinical) and again in 2022 after clinical exposure (post-clinical) to assess the viability of elective dissection post-pandemic. A mixed-method approach was used for the assessment of test scores, learning preference surveys, learning activities rankings, and thematic analyses.

Case-based radiological anatomy instruction using cadaveric MRI imaging and delivered with extended reality web technology.

Purpose: Extended reality (XR) technology enhances learning in medical education. The purpose of this study was to develop and apply a case-based approach for teaching radiological anatomy utilizing XR technology for improved student exploration and engagement.

Methods: The workflow consisted of MRI scanning cadavers followed by radiological, pathological, and anatomical assessment, and finally case presentation based on XR visualizations and student interaction.

Three dimensional radial echo planar imaging for functional MRI.

Purpose: To demonstrate a novel 3D radial echo planar imaging (3D REPI) sequence for flexible, rapid, and motion-robust sampling in fMRI.

Methods: The 3D REPI method expands on the recently described golden angle rotated EPI trajectory using radial batched internal navigator echoes (TURBINE) approach by exploiting the unused perpendicular direction in the EPI readout to form fast analogues of rotated stack of stars or spirals trajectories that cover all 3 dimensions of k-space. An iterative conjugate gradient algorithm with SENSE reconstruction and time-segmented non-uniform fast Fourier transform (FFT) was used for parallel imaging acceleration and to account for the effects of B inhomogeneity.

Phospholipids are A Potentially Important Source of Tissue Biomarkers for Hepatocellular Carcinoma: Results of a Pilot Study Involving Targeted Metabolomics.

Background: Hepatocellular carcinoma (HCC) pathogenesis involves the alteration of multiple liver-specific metabolic pathways. We systematically profiled cancer- and liver-related classes of metabolites in HCC and adjacent liver tissues and applied supervised machine learning to compare their potential yield for HCC biomarkers.

Methods: Tumor and corresponding liver tissue samples were profiled as follows: Bile acids by ultra-performance liquid chromatography (LC) coupled to tandem mass spectrometry (MS), phospholipids by LC-MS/MS, and other small molecules including free fatty acids by gas chromatography-time of flight MS.

Radiofrequency phase encoded half-pulses in simultaneous multislice ultrashort echo time imaging.

Purpose: To describe a simultaneous multislice (SMS) ultrashort echo time (UTE) imaging method using radiofrequency phase encoded half-pulses in combination with power independent of number of slices (PINS) inversion recovery (IR) pulses to generate multiple-slice images with short T * contrasts in less than 3 min with close to an eightfold acceleration compared with a standard 2D approach.

Theory And Methods: Radiofrequency phase encoding is applied in an SMS (N = 4) excitation scheme using "sinc" half-pulses. With the use of coil sensitivity encoding (SENSE) and controlled aliasing in parallel imaging (CAIPI) in combination with a gradient echo 2D spiral readout trajectory and IR PINS pulses for contrast enhancement a fast UTE sequence is developed.

A circular echo planar sequence for fast volumetric fMRI.

Purpose: To demonstrate a circular EPI (CEPI) sequence as well as a generalized EPI reconstruction for fast fMRI with parallel imaging acceleration.

Methods: The CEPI acquisition was constructed using variable readout lengths and maximum ramp sampling as well as blipped-CAIPI z-gradient encoding for simultaneous multislice (SMS) and 3D volumetric imaging. A signal equation model with constant and linear phase terms was used to iteratively reconstruct images with low ghosting.

Activation of Aryl Halides by Nickel(I) Pincer Complexes: Reaction Pathways of Stoichiometric and Catalytic Dehalogenations.

Homolytic C-X bond cleavage of organohalides by the T-shaped nickel(I) complexes [LigNi(I)] 1 bearing the iso-PyrrMeBox ligand had been found previously to be the crucial activation step in the asymmetric hydrodehalogenation of geminal dihalides. Here, this mechanistic investigation is extended to aryl halides, which allowed a systematic study of the activation process by a combination of experimental data and density functional theory modeling. While the activation of both aryl chlorides and geminal dichlorides appears to proceed via an analogous transition state, the generation of a highly stabile nickel(II)aryl species in the reaction of the aryl chlorides for the former represents a major difference in the reactive behavior.

Electronic structure and reactivity of nickel(i) pincer complexes: their aerobic transformation to peroxo species and site selective C-H oxygenation.

The study is aimed at a deeper understanding of the electronic structure of the T-shaped nickel(i) complex [Lig(iso)Ni] (), bearing the iso-PyrrMeBox (bis(oxazolinylmethylidene)pyrrolidinido) pincer ligand, and its CO adduct [Lig(iso)Ni(CO)] () as well as to provide insight into the mechanism of autoxidation of the different nickel peroxo species of this ligand type. CO was found to react reversibly with complex resulting in the corresponding CO adduct . The EPR data as well as the results of DFT modeling revealed significant differences in the electronic structure of and .

Catalytic C-F bond activation of geminal difluorocyclopropanes by nickel(I) complexes via a radical mechanism.

Nickel(II) fluorido complexes bearing NNN-pincer ligands were found to be catalysts in the hydrodefluorination of geminal difluorocyclopropanes which undergo ring-opening to form the corresponding monofluoroalkenes in good yield and high Z-selectivities. Evidence for a radical based mechanism involving nickel(I) and nickel hydrido complexes as key intermediates was obtained in the corresponding stoichiometric reactions.

Structural characterization of a hydroperoxo nickel complex and its autoxidation: mechanism of interconversion between peroxo, superoxo, and hydroperoxo species.

Pincer-stabilized nickel(I) complexes readily react with molecular oxygen to form dinuclear 1,2-μ-peroxo-bridged nickel(II) complexes, which are the major components of a dynamic equilibrium with the corresponding mononuclear superoxo species. The peroxo complexes further react with hydrogen peroxide to give the corresponding nickel(II) hydroperoxides. One of these hitherto elusive species was characterized by X-ray diffraction for the first time [O-O bond length: 1.

Stereoselective hydrodehalogenation via a radical-based mechanism involving T-shaped chiral nickel(I) pincer complexes.

We herein report the catalytic enantioselective hydrodehalogenation based on the interplay of a chiral molecular nickel(I)/nickel(II)hydride system. Prochiral geminal dihalogenides are dehalogenated via a secondary configurationally unstable, potentially metal-stabilized radical intermediate. In a subsequent step, the liberated radical is then trapped by the nickel(II) hydrido complex, present in a large excess under the catalytic conditions, which in turn induces the enantioselectivity during the hydrogen atom transfer onto the radical intermediate.

Copper-boxmi complexes as highly enantioselective catalysts for electrophilic trifluoromethylthiolations.

The enantioselective trifluoromethylthiolation of β-ketoesters using chiral copper-boxmi complexes as catalysts is reported. A number of α-SCF3-substituted β-ketoesters have been obtained with up to >99% enantiomeric excess (ee), and the trifluoromethylthiolated products were then transformed diastereoselectively to α-SCF3-β-hydroxyesters with two adjacent quaternary stereocenters.