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It has been observed in numerical experiments that adding a cargo to a motor protein can regularize its gait. Here we explain these results via asymptotic analysis on a general stochastic motor protein model. This analysis permits a computation of various observables (e.g., the mean velocity) of the motor protein and shows that the presence of the cargo also makes the velocity of the motor nonmonotone in certain control parameters (e.g., ATP concentration). As an example, we consider the case of a single myosin-V protein transporting a cargo and show that, at realistic concentrations of ATP, myosin-V operates in the regime which maximizes motor velocity. Our analysis also suggests an experimental regimen which can test the efficacy of any specific motor protein model to a greater degree than was heretofore possible.

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, photoemission spectroscopy (PES), and contact angle measurements have been used to examine the structure and bonding of self-assembled monolayers (SAMs) prepared on Au(111) from the positional isomers of mercaptobenzoic acid (MBA). The isomer of MBA and solvent chosen in SAM preparation has considerable bearing upon film morphology. Carbon K-edge NEXAFS measurements indicate that the monomers of 2-, 3-, and 4-MBA have well-defined orientations within their respective SAMs. Monomers of 3- and 4-MBA assume an upright orientation on the Au substrates in monolayers prepared using an acetic acid in ethanol solvent. The aryl ring and carboxyl group of these molecules are tilted from the surface normal by a colatitudal angle of ~30°. Preparation of 4-MBA SAMs using pure ethanol solvent, a more traditional means of synthesis, had no appreciable effect upon the monomer orientation. Nonetheless, S(2p) PES measurements illustrate that it results in extensive bilayer formation via carboxyl group hydrogen-bonding between 4-MBA monomers. In 2-MBA monolayers prepared using acetic acid/ethanol solvent, the monomers adopt a more prostrate orientation on the Au substrates, in which the aryl ring and carboxyl group of the molecules are tilted ~50° from the surface normal. This configuration is consistent with an interaction between both the mercaptan sulfur and carboxyl group of 2-MBA with the underlying substrate. S(2p) and C(1s) PES experiments provide supporting evidence for a bidentate interaction between 2-MBA and Au(111).

We have identified conditions in which the atomic force microscope can be used to stretch a meniscus of a perfluoropolyether (PFPE) lubricant pinned between an AFM tip and a nanometer-thick PFPE film to obtain the disjoining pressure of the film. Under quasi-equilibrium conditions, the chemical potential of the film can be equated to that of the stretched meniscus. A theory is presented that provides a complete description of the capillary force of a stretched meniscus. Fits of the theory to quasi-equilibrium force-extension curves yield the effective meniscus curvature and, by extension, the disjoining pressure of the underlying film. AFM force curves collected at varying film thicknesses compare very well with predictions from Lifshitz theory of dispersive interactions in thin films, with no adjustable parameters. This complete description of meniscus deformation during atomic force microscopy force-extension experiments makes possible the measurement of unknown disjoining pressures as required for screening of lubricant-overcoat combinations required for next-generation data storage systems.

Hallux limitus is one of the most prevalent, debilitating disorders of the first metatarsophalangeal joint, and it has many proposed etiologies. This article reviews these etiologies, focusing primarily on the pes planus foot. The pes planus foot type is often associated with symptomatic hallux limitus and the accessory navicular. This article discusses this correlation, although a causal relationship has not been proven. The prevalence and classification of the accessory navicular are also discussed. Clinical cases involving symptomatic hallux limitus occurring concomitantly with an accessory navicular are reviewed, including radiographic findings, symptoms, and surgical treatment. (J Am Podiatr Med Assoc 92(6): 359-365, 2002)

The speed of the evolution in ankle arthroscopy is staggering. Indications for the procedure continue to grow, and surgeons’ skill in applying the latest technology to perform surgery better has advanced significantly in a short period of time. Certainly the biggest limitation to this point has been limited access to lesions in the posterior ankle joint. As proficiency and technology improve, better arthroscopic access will be gained to lesions that have traditionally required open arthrotomy.

This preliminary report on the Chelex-based extraction method of HPV DNA from verruca plantaris is the first step in a series of studies on verruca plantaris undertaken, jointly, by the Departments of Podiatric Medicine and Microbiology at Des Moines University-Osteopathic Medical Center, Des Moines, Iowa. Current projects include the development of new primers for PCR studies of HPV, exploration of different viral DNA extraction methods, and surveys concerning treatment, success of therapies, and the epidemiology of verruca plantaris.

BACKGROUND: Interventions to improve sleep in fibromyalgia may generalize to improvements in multiple symptom domains. Delta-embedded music, pulsating regularly within the 0.25 Hz to 4 Hz frequency band of brain wave activity, has the potential to induce sleep.OBJECTIVES: To assess the effects of a delta-embedded music program over four weeks for sleep induction in patients with fibromyalgia.METHODS: The present unblinded, investigator-led pilot study used a within-subject design. Analysis was based on 20 individuals with fibromyalgia who completed the study, of the 24 recruited into the study. The primary outcome variables were the change from baseline in Fibromyalgia Impact Questionnaire (FIQ) and Jenkins Sleep Scale scores. A patient global impression of change was measured on a seven-point Likert scale. Secondary outcome measures, comprised of items 5, 6 and 7 of the FIQ, were used as indicators of pain, tiredness and being tired on awakening.RESULTS: The FIQ median score of 76.4 (95% CI 61.3 to 82.1) at baseline improved to 60.3 (95% CI 53.1 to 72.0; P=0.004). The Jenkins Sleep Scale median value of 17.5 (95% CI 15.5 to 18.5) at baseline fell to 12.5 (95% CI 8.5 to 14.5; P=0.001) at study completion. The outcomes of the patient global impression of change ratings were mostly positive (P=0.001). Being tired on awakening declined significantly from a median of 9.0 (95% CI 8.0 to 10.0) to 8.0 (95% CI 5.5 to 9.0; P=0.021). However, there was no significant improvement in pain level (baseline median 7.5 [95% CI 7.0 to 8.5] versus study completion median 7.0 [95% CI 6.5 to 8.0]; P=0.335) or tiredness (baseline median 9.0 [95% CI 8.0 to 9.5] versus study completion median 8.0 [95% CI 6.0 to 8.5]; P=0.061). There were no serious adverse events.CONCLUSIONS: Delta-embedded music is a potential alternative therapy for fibromyalgia.

Several letters to the editor are presented in response to articles including one the story of "The Moral Pirates," one which requests for patterns in crocheting, and one on admiration expressed by one reader in reading the book.