Publications by authors named "Johns M"

Magnetic resonance methods have been used to probe the evolution of the internal micro-structure of an industrially important detergent mixture, as a function of total water content. Measurements of the apparent diffusion coefficient of the water content were obtained as a function of diffusion observation time. These data were interpreted to render the surface-to-volume ratio and tortuosity of the pore space in which the water resided.

View Article and Find Full Text PDF

Magnetic resonance imaging (MRI) is a noninvasive technique that can be used to visualize mixing processes in optically opaque systems in up to three dimensions. Here, MRI has been used for the first time to obtain both cross-sectional velocity and concentration maps of flow through an optically opaque Y-shaped microfluidic sensor. Images of 23 micromx23 microm resolution were obtained for a channel of rectangular cross section (250 micromx500 microm) fed by two square inlets (250 micromx250 microm).

View Article and Find Full Text PDF

Objectives: Most U.S. studies of acute liver failure (ALF) patients have been conducted at tertiary care liver transplantation centers.

View Article and Find Full Text PDF

Voice therapy is a preferred treatment for many voice problems. Many patients referred to voice therapy by their otolaryngologist fail to follow through with the recommendation. Unlike other behavior change therapies, there are no studies documenting the incidence of poor patient attendance in voice therapy.

View Article and Find Full Text PDF

Regions of the arterial tree exposed to laminar flow, which exerts high shear stress, are protected from inflammation, endothelial cell (EC) death and atherosclerosis. TNFalpha activates NF-kappaB transcription factors, which potentially exert dual functions by inducing both proinflammatory and cytoprotective transcripts. We assessed whether laminar shear stress protects EC by modulating NF-kappaB function.

View Article and Find Full Text PDF

The use of a zeolite (clinoptilolite) to protect poplar plants from lithium-contaminated soil has been studied using magnetic resonance imaging. Lithium was used as a model contaminant as it could be tracked directly using specific nuclear magnetic resonance probes, rather than relying on relaxation time effects on protons due to paramagnetic solutes. The sorption of lithium to the zeolite was investigated both in static and dynamic systems; lithium was found to sorb readily to the zeolite over time.

View Article and Find Full Text PDF

A simulation-based study to predict the impact of biofilm growth on displacement distributions for flow of water through a supporting packed bed is presented. The lattice Boltzmann method and a directed random walk algorithm are used, and are applied to the system with and without biofilm being present. The aim of this simulation study is to model the anomalous transport dynamics induced by biofilm, as reported in the literature, and thus to study the impact of observation time, delta, on the shape of the displacement distributions (propagators).

View Article and Find Full Text PDF

Purpose: To characterize resident burnout on a national scale with a large sample size and to identify associated modifiable factors to minimize burnout and improve the quality of residency education.

Method: A survey was mailed to all 1,364 U.S.

View Article and Find Full Text PDF

Analysis of diffusion measurements as a function of observation time (Delta), to calculate surface-to-volume ratios (S/V) and tortuosities (kappa), is a useful tool in the characterisation of porous media using NMR. However, using conventional pulsed field gradient (PFG) measurements, this requires long total experiment times (typically hours). Here, we show how the rapid diffusion measurement pulse sequence, Difftrain, can be used to provide the required experimental data much more rapidly (typically within minutes) with a consequential reduction in total experiment time of typically over an order of magnitude.

View Article and Find Full Text PDF

We use displacement encoding pulsed field gradient (PFG) nuclear magnetic resonance to measure Fourier components S(q) of flow displacement distributions P(zeta) with mean displacement (zeta) for Newtonian and non-Newtonian flows through rocks and bead packs. Displacement distributions are non-Gaussian; hence, there are finite terms above second order in the cumulant expansion of ln(S(q)). We describe an algorithm for an optimal self-consistent cumulant analysis of data, which can be used to obtain the first three (central) moments of a non-Gaussian P(zeta), with error bars.

View Article and Find Full Text PDF
Article Synopsis
  • The study focused on using two types of compost—green waste and sewage sludge—mixed with minerals to clean up metal-contaminated brownfield sites for transformation into greenspace.
  • The green waste compost significantly reduced the leaching of cadmium (Cd) and zinc (Zn) by up to 48%, while the sewage sludge compost increased Zn leaching but effectively reduced plant uptake of several metals by up to 80%.
  • The findings indicate that the immobilization and bioavailability of metals are mainly influenced by the interactions between metals and organic matter, with mineral amendments having only minimal impact.
View Article and Find Full Text PDF

In 2001, senior administrators in Emory University's Woodruff Health Sciences Center (WHSC) designated leadership as the central element of a new strategic plan, believing that an academic health center (AHC) requires excellence in leadership at all organizational levels to carry out the tripartite mission of teaching, research, and patient care. Leadership development in academic medicine presents unique challenges, however, including a wide range of professional roles and diverse operational centers that may be obstacles to unifying a leadership team in the pursuit of a central mission. Many administrators within academic medicine, although highly competent in their areas of expertise, possess limited leadership skills.

View Article and Find Full Text PDF

PFG NMR methods are frequently used as a means of probing both coherent and incoherent molecular motions of fluids contained within heterogeneous porous media. The time scale over which molecular displacements can be probed in a conventional PFG NMR experiment is limited by the relaxation characteristics of (1)H - the nucleus that is typically observed. In multiphase systems, due to its sensitivity to susceptibility gradients and interactions with surfaces,(1)H signal is frequently characterized by rapid T(1) and T(2) relaxation.

View Article and Find Full Text PDF

Antiendothelial cell antibodies (AECAs) are commonly detectable in diseases associated with vascular injury, including systemic lupus erythematosus (SLE), systemic sclerosis, Takayasu arteritis, Wegener granulomatosis, Behçet syndrome, and transplant arteriosclerosis. Here, we explore the hypothesis that these antibodies might augment polymorphonuclear leukocyte (PMN) adhesion to endothelium in inflammation. Initially, we established that a mouse IgG mAb bound to endothelial cells (ECs) significantly increased PMN adhesion to cytokine-stimulated endothelium in an FcgammaRIIa-dependent manner.

View Article and Find Full Text PDF

Cultivated rice (Oryza sativa) is comprised of two subspecies: japonica and indica. Polymorphism levels between putative homologues were determined for genes whose japonica homologue had been classified into functional categories using the Gene Ontology (GO) system. Genes were partitioned into below-average and above-average polymorphism groups, and then the set of genes having each GO term was checked for the randomness of its distribution into these polymorphism groups using a series of False Discovery Rate (FDR) tests.

View Article and Find Full Text PDF

Objectives: To characterize geriatric dysphonia, including its prevalence, quality-of-life impairment, and association with overall health status.

Design: A validated survey-based study of geriatric dysphonia.

Setting: An independent living facility for geriatric individuals.

View Article and Find Full Text PDF

The objective of the study is to determine the efficacy of voice therapy in the treatment of age-related dysphonia. The study was conducted using a retrospective case-control chart review. The medical records of 54 patients older than 60 years diagnosed with age-related dysphonia without complicating diagnoses were reviewed.

View Article and Find Full Text PDF

Previous work has suggested that the protein tyrosine phosphatase, SHP-2, may act to facilitate angiotensin II (Ang II)-mediated, Jak2-dependent signaling. However, the mechanisms by which this occurs are not known. Here, Ang II-mediated, Jak2-dependent signaling was analyzed in a fibroblast cell line lacking the N-terminal, SH2 domain of SHP-2 (SHP-2(Delta46-110)).

View Article and Find Full Text PDF