Non-holonomic Euler-Poincare´ equations and stability in Chaplygin's sphere

A method of reducing several classes of non-holonomic mechanical systems that are defined on semidirect products of Lie groups is developed. The method reduces the Lagrange-d'Alembert principle to obtain a reduced constrained principle that determines Euler-Poincaré equations on the reduced space. The theory is demonstrated by deriving the reduced equations of motion for several examples of rigid bodies that roll without slipping. Our method of reduction is then used as a framework to obtain several results related to Chaplygin's sphere. The first result determines the stability of the relative equilibria of Chaplygin's sphere: the ball spins stably about the principal axes with the largest and smallest moments of inertia and unstably about the middle axis. The next results use two different approaches to stabilize the rotation of the ball about its middle axis. The first approach controls an internal rotor that has been added to the ball and the second approach controls the plane the ball rolls upon by forces of horizontal translations. We briefly consider the system where the plane is allowed to react to the motion of the ball, stating the equations of motion and identifying the steady rotations.     

Data input model for virtual reality-aided facility layout

An approach to automatically extract three dimensional (3D) models (that is, geometries and topologies) of physical objects in a facility is described. The rationale for this work is its repeated use in efficiently developing databases of 3D objects for applying virtual reality (VR) tools in detailed layout decision support. Obtaining 3D object models can be a challenging task. Sometimes they are available, for example, in a Computer-Aided Design (CAD) database and these can be readily imported into a VR database. But on many occasions one is not so fortunate and these object models have to be created in correlation to an existing or proposed facility, which can be an extremely tedious and time consuming task. A time efficient and economical alternative is to use video camera images, but quickly and accurately capturing the depth information from 2D camera images has so far remained elusive because the existing methodologies are too general purpose and operate at a lower level of abstraction, namely digitized images. We have developed a method for directly inputting 3D objects into VR-aided facility layout models, by integrating the strengths of previously tried and tested technological components: (i) camera calibration; (ii) image processing; (iii) stereo vision; and (iv) Delaunay triangulation. The techniques described here are embedded in a prototype architecture and toolkit called MIRRORS (Methodology for Inputting Raw Recordings into 3D Object Renderings for Stereo). The primary contribution of this paper is that it has been able to design an integrated system to build 3D object models from 2D images. The MIRRORS system has been primarily designed for objects without free-form surfaces and whose shape can be recovered from a relatively nondense set of points.     

A blue encrustation found on skeletal remains of Americans missing in action in Vietnam

We review and present current evidence supporting independent regulation of nuclear Ca2+ ([Ca2+]n). The nucleus and nuclear envelope contain proteins to both regulate and respond to changes in [Ca2+]n. However, this does not prove that [Ca2+]n is independently regulated from cytosolic Ca2+ ([Ca2+]c). Studies using fluorescent dyes suggested that changes in [Ca2+]n differed in magnitude from changes in [Ca2+]c. These studies have been criticised as the nuclear environment alters the fluorescent characteristics of these dyes. We have evaluated this question with aequorin targeted to the nucleus and cytoplasm and shown that the characteristics of the indicators are not altered in their respective environments. We have demonstrated that different stimuli induce changes in [Ca2+]n and [Ca2+]c that vary both temporally and in magnitude. The nucleus appeared to be shielded from increases in [Ca2+]c, either through a mechanism involving the nuclear envelope or by cytosolic buffering of localised increases in Ca2+. In addition, agonist stimulation resulted in an increase in [Ca2+]n, consistent with release from the perinuclear Ca2+ store. There was a stimulus dependence of the relation between [Ca2+]n and [Ca2+]c suggesting differential regulation of [Ca2+]n. These results have important implications for the role of Ca2+ as a specific regulator of nuclear events through Ca2+ binding proteins. In addition, they highlight the advantages of using targeted aequorin in intact cells to monitor changes in organelle [Ca2+].     

Xanthoma disseminatum with marked mucocutaneous involvement

HISTORY AND CLINICAL FINDINGS: When aged 23 years, a now 36-year-old man was first diagnosed as having xanthomas on the upper arms and shoulders. Xanthomas then progressed, affecting both the skin and the laryngo-pharyngeal mucosa. They were so marked that several laser-surgical interventions for their removal in the phayngo-laryngeal tract were necessary to ensure unimpaired breathing. There were also extensive confluent symmetrical cutaneous xanthomas over the upper and lower arms, the face, neck and trunk. Xanthomas and scars in the pharynx and larynx necessitated marked nasal breathing. INVESTIGATIONS: There was no laboratory evidence of abnormal lipid metabolism. The concentrations of cholesterol, triglycerides, lipoprotein (a), apolipoprotein A-1, apolipoprotein B, apolipoprotein E phenotype and steroles were all normal. The biochemical composition of LDL, VLDL and HDL particle was also unremarkable. Histological examination of resected xanthomas revealed dense infiltrations of the interstitial spaces by foam-cell histiocytes with multiple lipid vacuoles, typical of xanthoma disseminatum. TREATMENT AND COURSE: Neither probucol nor cholesterol synthesis enzyme inhibitors nor glucocorticoid medication influenced the xanthomas. The only effective treatment was removal of the most unsightly or obstructing lesions. But the sars left removal in the mucocutaneous regions caused obstruction in the laryngopharyngeal tract. CONCLUSION: The cause of xanthoma disseminatum remains unknown. Skeletal muscle can also be extensively infiltrated. This case shows similarities to Erdheim-Chester disease, another are xanthomatous condition.     

Thecal cell-granulosa cell interactions involve a positive feedback loop among keratinocyte growth factor, hepatocyte growth factor, and Kit ligand during ovarian follicular development

Interactions between mesenchymal-derived thecal cells and epithelial-derived granulosa cells are essential for follicular development in the ovary. These mesenchymal-epithelial cell interactions are in part mediated by keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and Kit ligand (KL). This study investigates the hypothesis that thecal cell-derived growth factors (e.g. KGF and HGF) regulate granulosa cell function, and granulosa cell-derived growth factors (e.g. KL) regulate thecal cell function. Gonadotropin regulation of this cell-cell interaction is also examined. Sensitive quantitative RT-PCR assays were used to analyze gene expression of KGF, HGF, and KL in the ovary. Thecal cell-derived KGF and HGF stimulated KL expression in bovine granulosa cells. Granulosa cell-derived KL stimulated KGF and HGF expression in bovine thecal cells. These results suggest that thecal and granulosa cells interact in a positive feedback loop mediated by KGF, HGF, and KL. Previous studies have suggested that gonadotropins (i.e. FSH and LH) regulate locally produced growth factor expression in the ovary. Treatment of bovine granulosa cells with FSH and hCG (a LH agonist) directly stimulated KL expression. The LH agonist hCG was also found to stimulate both KGF and HGF expression in thecal cells. The actions of gonadotropins on follicular development may in part be indirectly regulated by KL, KGF, and HGF expression. A novel positive feedback loop was identified between thecal cells and granulosa cells that is mediated by KL, KGF, and HGF. Thecal cell-derived KGF and HGF can stimulate granulosa cell-derived KL expression, and KL, in turn, can stimulate thecal cell-derived KGF and HGF expression. Combined observations support the hypothesis that mesenchymal-epithelial cell interactions between thecal and granulosa cells can play a significant role during ovarian follicular development and mediate gonadotropin actions.     

Metatarsophalangeal and intermetatarsal angle: different values and interpretation of postoperative results dependent on the technique of measurement

For measurement of the first metatarsophalangeal angle and intermetatarsal angle I-II, five different methods for drawing the axis of the first metatarsal have been published. This study aimed to evaluate differences in the resulting angles that depend on the method of drawing this axis. Using pre- and postoperative radiographs of 20 patients who had surgery on the hallux (chevron procedure), highly significant differences were found: mean values for the preoperative metatarsophalangeal angle ranged from 27.3 degrees to 31.9 degrees; the mean postoperative values were calculated at 8.6 degrees to 20.3 degrees. The preoperative mean of intermetatarsal angle I-II showed values from 13.0 degrees to 17.6 degrees; the postoperative mean ranged from 5.2 degrees to 16.7 degrees. These differences--especially in the postoperative evaluation--resulted in a postoperative improvement between 11.6 degrees and 20.8 degrees for the metatarsophalangeal angle and between 0.9 degrees and 10.0 degrees for the intermetatarsal angle. These wide differences seem to be unacceptable for angles as a criterion of success in surgery on the hallux. The reason for these discrepancies can be found in the different relations of the points of reference to the anatomical outline of the metatarsal and the site of osteotomy. As a consequence of this study, defining the axis of the first metatarsal as a line connecting the center of the articular surface of the metatarsal head and the center of the proximal articulation can be recommended as the most appropriate method. The resulting angles are independent of the type of surgery performed on the hallux.     

The effects of a health promotion-health protection intervention on behavior change: the WellWorks Study

OBJECTIVES: This study assessed the effects of a 2-year integrated health promotion-health protection work-site intervention on changes in dietary habits and cigarette smoking. METHODS: A randomized, controlled intervention study used the work site as the unit of intervention and analysis; it included 24 predominantly manufacturing work sites in Massachusetts (250-2500 workers per site). Behaviors were assessed in self-administered surveys (n = 2386; completion rates = 61% at baseline, 62% at final). Three key intervention elements targeted health behavior change: (1) joint worker-management participation in program planning and implementation, (2) consultation with management on work-site environmental changes, and (3) health education programs. RESULTS: Significant differences between intervention and control work sites included reductions in the percentage of calories consumed as fat (2.3% vs 1.5% kcal) and increases in servings of fruit and vegetables (10% vs 4% increase). The intervention had a significant effect on fiber consumption among skilled and unskilled laborers. No significant effects were observed for smoking cessation. CONCLUSIONS: Although the size of the effects of this intervention are modest, on a populationwide basis effects of this size could have a large impact on cancer-related and coronary heart disease end points.     

Neutralizing antibodies from the sera of human immunodeficiency virus type 1-infected individuals bind to monomeric gp120 and oligomeric gp140

Antibodies that neutralize primary isolates of human immunodeficiency virus type 1 (HIV-1) appear during HIV-1 infection but are difficult to elicit by immunization with current vaccine products comprised of monomeric forms of HIV-1 envelope glycoprotein gp120. The limited neutralizing antibody response generated by gp120 vaccine products could be due to the absence or inaccessibility of the relevant epitopes. To determine whether neutralizing antibodies from HIV-1-infected patients bind to epitopes accessible on monomeric gp120 and/or oligomeric gp140 (ogp140), purified total immunoglobulin from the sera of two HIV-1-infected patients as well as pooled HIV immune globulin were selectively depleted of antibodies which bound to immobilized gp120 or ogp140. After passage of each immunoglobulin preparation through the respective columns, antibody titers against gp120 and ogp140 were specifically reduced at least 128-fold. The gp120- and gp140-depleted antibody fraction from each serum displayed reduced neutralization activity against three primary and two T-cell line-adapted (TCLA) HIV-1 isolates. Significant residual neutralizing activity, however, persisted in the depleted sera, indicating additional neutralizing antibody specificities. gp120- and ogp140-specific antibodies eluted from each column neutralized both primary and TCLA viruses. These data demonstrate the presence and accessibility of epitopes on both monomeric gp120 and ogp140 that are specific for antibodies that are capable of neutralizing primary isolates of HIV-1. Thus, the difficulties associated with eliciting neutralizing antibodies by using current monomeric gp120 subunit vaccines may be related less to improper protein structure and more to ineffective immunogen formulation and/or presentation.     

Phospholipid pool, lipid peroxidation, and superoxide dismutase activity under various types of oxidative stress of the brain and the effect of low-energy infrared laser irradiation

The effect of low-energy infrared laser irradiation on the phospholipid pool, lipid peroxidation, and superoxide dismutase activity in the brain of white rats was studied in experimental ischemia, reperfusion, and acute edema. These models are characterized by oxidative stress; the contents of tri- and diphosphoinositides and sphingomyelins were lowered, whereas the levels of phosphatidylserine and phosphatidylethanolamine did not change, and the amount of phosphatidylcholine was increased. In acute brain edema, the contents of hydroperoxides and malonic dialdehyde in enzymatic and nonenzymic lipid peroxidation systems were increased in mitochondrial and microsomal fractions and the level of arachidonic acid was significantly elevated. Infrared laser irradiation contributes to the correction of the changes in the phospholipid pool; laser irradiation lowered the increased levels of hydroperoxides and malonic dialdehyde and elevated superoxide dismutase activity in the brain during ischemia, reperfusion, and acute edema of the brain. The data suggest that low-energy infrared laser irradiation has certain neuroprotective activity in various types of oxidative stress including ischemia, reperfusion, and acute edema of the brain.