Publications by authors named "Meek G"

Background: Studies have found a higher risk of comorbid anxiety and depression among patients with inflammatory bowel disease (IBD) compared with healthy individuals. If left untreated, comorbid depression and anxiety in patients with IBD can lead to poorer health outcomes and an increased healthcare utilization. The goal of this work was to develop a consensus statement to begin to address patient and provider needs and responsibilities related to screening and treatment of depression and anxiety symptoms among patients with IBD.

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Quiescent stem cells are activated in response to a mechanical or chemical injury to their tissue niche. Activated cells rapidly generate a heterogeneous progenitor population that regenerates the damaged tissues. While the transcriptional cadence that generates heterogeneity is known, the metabolic pathways influencing the transcriptional machinery to establish a heterogeneous progenitor population remains unclear.

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Non-biological foldamers are a promising class of macromolecules that share similarities to classical biopolymers such as proteins and nucleic acids. Currently, designing novel foldamers is a non-trivial process, often involving many iterations of trial synthesis and characterization until folded structures are observed. In this work, we aim to tackle these foldamer design challenges using computational modeling techniques.

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Our purpose in this study was to examine the effectiveness of yoga to address multiple risk factors of falling in active and low active older adults. Community-dwelling older adults ( = 35) over the age of 65 actively participated in either a yoga program, an exercise program, or a no-program control. Participants completed measures associated with falling risks.

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Coarse-grained modeling can be used to explore general theories that are independent of specific chemical detail. In this paper, we present cg_openmm, a Python-based simulation framework for modeling coarse-grained hetero-oligomers and screening them for structural and thermodynamic characteristics of cooperative secondary structures. cg_openmm facilitates the building of coarse-grained topology and random starting configurations, setup of GPU-accelerated replica exchange molecular dynamics simulations with the OpenMM software package, and features a suite of postprocessing thermodynamic and structural analysis tools.

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Penetrating trauma by energized fragments is the most common injury from explosive devices, the main threat in the contemporary battlefield. Such devices produce projectiles dependent upon their design, including preformed fragments, casings, glass, or stones; these are subsequently energized to high velocities and cause serious injuries to the body. Current body armor focuses on the essential coverage, which is mainly the thoracic and abdominal area, and can be heavy and cumbersome.

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When simulating nonadiabatic molecular dynamics, choosing an electronic representation requires consideration of well-known trade-offs. The uniqueness and spatially local couplings of the adiabatic representation come at the expense of an electronic wave function that changes discontinuously with nuclear motion and associated singularities in the nonadiabatic coupling matrix elements. The quasi-diabatic representation offers a smoothly varying wave function and finite couplings, but identification of a globally well-behaved quasi-diabatic representation is a system-specific challenge.

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We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities.

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Spikes in the time-derivative coupling (TDC) near surface crossings make the accurate integration of the time-dependent Schrödinger equation in nonadiabatic molecular dynamics simulations a challenge. To address this issue, we present an approximation to the TDC based on a norm-preserving interpolation (NPI) of the adiabatic electronic wave functions within each time step. We apply NPI and two other schemes for computing the TDC in numerical simulations of the Landau-Zener model, comparing the simulated transfer probabilities to the exact solution.

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Purpose: This study was designed to examine the on-road driving performance of drivers with hemianopia and quadrantanopia compared with age-matched controls.

Methods: Participants included persons with hemianopia or quadrantanopia and those with normal visual fields. Visual and cognitive function tests were administered, including confirmation of hemianopia and quadrantanopia through visual field testing.

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Purpose: To develop a questionnaire assessing vision-targeted health-related quality of life in older adults residing in nursing homes.

Methods: Using content previously identified through structured interviews with nursing home residents, the 57-item Nursing Home Vision-Targeted Health-Related Quality of Life questionnaire (NHVQoL) was drafted with nine subscales - general vision, reading, ocular symptoms, mobility, psychological distress, activities of daily living, activities/hobbies, adaptation/coping and social interaction. Construct validity and internal consistency and test-retest reliability of subscales were evaluated in a sample of adults >or=60 years old residing in nursing homes in Birmingham, Alabama, who had Mini Mental State Exam (MMSE) scores of >or=13.

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Objective: To examine the effect of treating uncorrected refractive error through spectacle correction on vision-targeted health-related quality of life and depressive symptoms in nursing home residents.

Methods: Persons aged 55 years or older residing in nursing homes in Birmingham, Alabama, having uncorrected refractive error were randomly assigned to either immediate spectacle correction of uncorrected refractive error or delayed correction (after the 2-month follow-up visit).

Main Outcome Measures: Vision-targeted health-related quality of life (measured with the Nursing Home Vision-Targeted Health-Related Quality-of-Life Questionnaire and the VF-14) and depressive symptoms (measured with the Geriatric Depression Scale), assessed at baseline and at 2 months.

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Objective: To characterize habitual visual acuity, contrast sensitivity, spectacle use, and eye care utilization in a large sample of older adults residing in nursing homes.

Methods: Of 33 nursing homes identified in Birmingham, Alabama, 17 served as sites. Eligibility criteria included age 55 years or older, English-speaking, and Mini-Mental State Examination score of 13 or higher.

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Aim: To assess the impact of cataract surgery in nursing home residents on health-related quality of life, as compared to those who have cataracts but who do not undergo surgery.

Methods: A prospective cohort study enrolled 30 nursing home residents (>or=60 years old) who had cataracts and underwent cataract surgery, and evaluated vision-targeted and generic health-related quality of life and depressive symptoms before and approximately 4 months after surgery. This cataract surgery group was compared to 15 nursing home residents who had cataracts but who did not have surgery, over the same timeframe.

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In model studies towards the quaternary centre at the heart of diazonamide A (early structure 2; revised structure 1), cyclisations of the alkene-substituted iodoaryls 4, 13, 18 and 23, under Heck reaction conditions, were shown to lead to the corresponding benzodihydrofuran 5, benzofuranone 14 and the oxindoles 19 and 24 respectively, in 50-80% yield. Further manipulation of the benzodihydrofuran 5 then led to the intermediates 30, 33 and 39, which make up parts of the oxazole-indole heterocyclic core in diazonamide A. Attempts to perform a corresponding 13-exo-trig Heck cyclisation from the precursor 46a, prepared from 44 and 45, leading to 47 were not successful.

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A robust and scalable procedure for the palladium-catalyzed dynamic kinetic asymmetric transformation of 3,4-epoxy-1-butene into (2R)-3-butene-1,2-diol with water as the cosolvent is reported. Examination of the effects of solvent and temperature led to the identification of conditions that permitted use of 0.025 mol % catalyst, providing (2R)-3-butene-1,2-diol in 84% isolated yield and 85% enantiomeric excess.

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The theoretical risk of prion transmission via surgical instruments is of current public and professional concern. These concerns are further heightened by reports of the strong surface affinity of the prion protein, and that the removal of organic material by conventional sterilization is often inadequate. Recent reports of contamination on sterilized endodontic files are of particular relevance given the close contact that these instruments may make with peripheral nerve tissue.

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[reaction: see text] Cyclopropanation of allylic tertiary amines using the Simmons-Smith reagent has been achieved by employing chelating groups in close proximity to the amine. The chelating groups promote cyclopropanation at the expense of N-ylide formation. Using pseudoephedrine as the chelating group, high diastereoselectivity is observed.

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