Biomedical subjects

James E Martin

Publications and source records attributed to James E Martin.

5 recordsLinked to original sources

PubMed2006

Use of the laryngeal mask airway in patients with severe muscular dystrophy who require sedation or anesthesia.

Severe muscular dystrophy (MD) has historically led to death in early adulthood, due to mainly cardiopulmonary complications. However, with newer methods of cardiac and respiratory management, survival has improved, and patients with MD are more frequently undergoing procedures requiring deep sedation or anesthesia. Respiratory management of these patients during procedures is challenging; safe and effective options for respiratory support are needed. In this report, we describe our experience using the laryngeal mask airway (LMA) to provide respiratory support during deep sedation or anesthesia for eight patients with severe MD during the following medical procedures: eight percutaneous endoscopic gastrostomy (PEG) placements, three lithotripsies, and placement of an implantable cardioverter-defibrillator. We also review the benefits and risks of the LMA in the context of other respiratory support options for people with MD, and the integral role of non-invasive positive pressure ventilation (NPPV) during induction of and recovery from deep sedation or general anesthesia.

Adult↗

PubMed2004

Using triaxial magnetic fields to create high susceptibility particle composites.

We report on the use of triaxial magnetic fields to create a variety of isotropic and anisotropic magnetic particle/polymer composites with significantly enhanced magnetic susceptibilities. A triaxial field is a superposition of three orthogonal ac magnetic fields, each generated by a Helmholtz coil in series resonance with a tunable capacitor bank. Field frequencies are in the range of 150-400 Hz. Because both the field amplitudes and frequencies can be varied, a rich variety of structures can be created. Perhaps the most unusual effects occur when either two or three of the field components are heterodyned to give beat frequencies on the order of 1 Hz. This leads to a striking particle dynamics that evolves into surprising structures during resin gelation. These structures are found to have perhaps the highest susceptibility that a particle composite can have. The susceptibility anisotropy of these composites can be controlled over a wide range by judicious adjustment of the relative field amplitudes. These experimental data are supported by large-scale Brownian dynamics simulations of the complex many-body interactions that occur in triaxial magnetic fields. These simulations show that athermal three-dimensional field heterodyning leads to structures with a susceptibility that is as high as that achieved with thermal annealing. Thus with coherent particle motions we can achieve magnetostatic energies that are quite close to the ground state.

Journal Article↗

PubMed2004

Results of a physician and respiratory therapist collaborative effort to improve long-term metered-dose inhaler technique in a pediatric asthma clinic.

BACKGROUND: Despite advances in therapy, asthma continues to be the chronic condition most responsible for school absenteeism and pediatric hospitalizations. This is especially true for inner-city children. We operate an inner-city Pediatric Asthma Compliance and Technique (PACT) clinic in which physicians and respiratory therapists collaborate to improve metered-dose inhaler (MDI) technique and outcomes among asthmatic children. OBJECTIVE: To determine the efficacy of our strategy for improving MDI technique and asthma outcomes. METHODS: Children referred to the PACT clinic underwent standardized assessment based on the Expert Panel Guidelines of the National Heart, Lung, and Blood Institute (NHLBI). Clinicians demonstrated and reinforced correct MDI technique at each visit. Using a standardized format we prospectively collected, at the patient's first visit (T1) and most recent visit (T2), data on demographics, MDI-technique scores (MDI steps done correctly; scale of 0-8), pulmonary function, and asthma severity (NHLBI classification scale: 1 = mild intermittent to 4 = severe persistent). Statistical analyses were performed using parametric and non-parametric tests. RESULTS: Of the 60 patients who attended the PACT clinic between 1999 and 2002, 15 were excluded from the study because of incomplete data recording. Mean duration from T1 to T2 was 11.8 +/- 9.5 months. At T1 and T2, respectively, the mean MDI-technique scores were 53% and 81%, the mean overall asthma severity scores were 2.6 and 2.3, and the mean overall pulmonary function severity scores were 2.4 and 2.1. MDI-technique scores significantly improved between TI and T2 (p < 0.001). The black patients had the largest improvement in MDI technique (p < 0.001), but their pulmonary function test results, overall asthma severity, and pulmonary function severity did not improve significantly. The white patients significantly improved both their MDI technique (p = 0.004) and their overall asthma severity scores (p = 0.005). CONCLUSION: In our PACT clinic asthmatic children showed sustained improvement in MDI technique, and some of the patients improved in pulmonary function and overall asthma severity score.

Administration, Inhalation↗

PubMed2003

Linear chains and chain-like fractals from electrostatic heteroaggregation.

The internal structure of materials prepared by aggregation of oppositely charged polystyrene spheres (electrostatic heteroaggregation) is investigated by static light scattering, optical microscopy, and Brownian dynamics simulation. Light scattering indicates ultralow mass fractal dimensions, as low as 1.2. Such low fractal dimensions, approaching the theoretical limit of a linear object, imply a chaining mechanism. Optical micrographs reveal linear chains with the particle charge alternating down the chains. Brownian dynamics simulation gives additional support for a chaining mechanism. For the polystyrene system (120-nm primary particle diameters), the fractal dimension is found to increase from 1.2 to 1.7 as the background electrolyte is increased. In terms of electrostatic screening, the results match those reported recently for larger polystyrene spheres. The low fractal dimensions appear to represent a crossover from linear chains to a structure of diffusion-limited aggregates; however, experiments under density-neutral conditions imply that sedimentation plays an important role in the formation of ultralow fractal dimensions. The practical implication is that microcomposites with a locally uniform distribution of starting materials and almost any degree of branching can be prepared from oppositely charged particles.

Journal Article↗

PubMed2002

A threat-appraisal perspective on employees' fears about antisocial workplace behavior.

This article uses a threat-appraisal model to examine the antecedents and consequences of antisocial behavior in an urban public school system. Teachers (compared with nonteachers) and middle and high school employees (compared with elementary school employees) reported higher levels of exposure to and fears about antisocial behavior. A path analysis demonstrated that threat appraisals partially mediate the relationship between antisocial behavior and job satisfaction and indirectly affect turnover intentions. These effects were consistent across high- and low-contact job types and across elementary, middle, and high school employees. The authors used the threat-appraisal model to describe the consequences of different interventions and found empirical evidence for employee voice and security measures as intervening variables.

Adolescent↗