Energy dissipation of a sphere rolling up a granular slope: Slip and deformation of the granular surface.

We experimentally investigate the dynamics of a sphere rolling up a granular slope. During the rolling-up motion, the sphere experiences slipping and penetration (groove formation) on the surface of the granular layer. The former relates to the stuck motion of the rolling sphere, and the latter causes energy dissipation due to the deformation of the granular surface. To characterize these phenomena, we measured the motion of a sphere rolling up a granular slope of angle α. The initial velocity v_{0}, initial angular velocity ω_{0}, angle of slope α, and density of the sphere ρ_{s} were varied. As a result, the penetration depth can be scaled solely by the density ratio between the sphere and granular layer. By considering the rotational equation of motion, we estimate the friction due to the slips. Besides, by considering energy conservation, we define and estimate the friction due to groove formation. Moreover, the translational friction is proportional to the penetration depth. Using these results, we can quantitatively predict the sphere's motion including stuck behavior.

Disordering two-dimensional magnet-particle configurations using bidispersity.

In various types of many-particle systems, bidispersity is frequently used to avoid spontaneous ordering in particle configurations. In this study, the relation between bidispersity and disorder degree of particle configurations is investigated. By using magnetic dipole-dipole interaction, magnet particles are dispersed in a two-dimensional cell without any physical contact between them. In this magnetic system, bidispersity is introduced by mixing large and small magnets. Then, the particle system is compressed to produce a uniform particle configuration. The compressed particle configuration is analyzed by using Voronoi tessellation for evaluating the disorder degree, which strongly depends on bidispersity. Specifically, the standard deviation and skewness of the Voronoi cell area distribution are measured. As a result, we find that the peak of standard deviation is observed when the numbers of large and small particles are almost identical. Although the skewness shows a non-monotonic behavior, a zero skewness state (symmetric distribution) can be achieved when the numbers of large and small particles are identical. In this ideally random (disordered) state, the ratio between pentagonal, hexagonal, and heptagonal Voronoi cells becomes roughly identical, while hexagons are dominant under monodisperse (ordered) conditions. The relation between Voronoi cell analysis and the global bond orientational order parameter is also discussed.

Sensitivity of Granular Force Chain Orientation to Disorder-Induced Metastable Relaxation.

A two-dimensional system of photoelastic disks subject to vertical tapping against gravity was experimentally monitored from ordered to disordered configurations by varying bidispersity. The packing fraction ϕ, coordination number Z, and an appropriately defined force-chain orientational order parameter S all exhibit as similar sharp transition with a small increase in disorder. A measurable change in S, but not ϕ and Z, was detected under tapping. We find disorder-induced metastability does not show configurational relaxation, but can be detected via force-chain reorientations.

Glycosylation of capsaicinoids with Panax ginseng stimulated by salicylic acid.

The efficient production of ß-glycosides of capsaicin and 8-nordihydrocapsaicin by cultured cells of Panax ginseng is reported. Capsaicin 4-O-(6-O-ß-D-xylopyranosyl)-ß-D-glucopyranoside (ß-primeveroside, 12%) together with capsaicin 4-O-ß-D-glucoside (6%) was isolated from the cell suspension of P. ginseng after one week of incubation with capsaicin. On the other hand, 8-nordihydrocapsaicin was glycosylated to 8-nordihydrocapsaicin 4-O-ß-D-glucoside (5%) and 8-nordihydrocapsaicin 4-O-ß-primeveroside (9%) by P. ginseng. Pretreatment of the cultured cells with salicylic acid greatly enhanced the glucosylation activity toward capsaicinoids. When 500 µM of salicylic acid was added to the cultures prior to the addition of substrate, capsaicin was converted into capsaicin 4-O-ß-D-glucoside (17%) and capsaicin ß-primeveroside (21%) and 8-nordihydrocapsaicin was glycosylated to 8-nordihydrocapsaicin 4-O-ß-D-glucoside (16%) and 8-nordihydrocapsaicin ß-primeveroside (15%).

Projectile interactions in granular impact cratering.

We present evidence for the interactions between a ball and the container boundaries, as well as between two balls, that are mediated by the granular medium during impact cratering. The presence of the bottom boundary affects the final penetration depth only for low drop heights with shallow filling, in which case, surprisingly, the penetration becomes deeper. By contrast the presence of the sidewall causes less penetration and also an effective repulsion. Repulsion is also found for two balls dropped side by side.

Avalanche statistics and time-resolved grain dynamics for a driven heap.

We probe the dynamics of intermittent avalanches caused by steady addition of grains to a quasi-two-dimensional heap. To characterize the time-dependent average avalanche flow speed v(t) , we image the top free surface. To characterize the grain fluctuation speed deltav(t) , we use speckle-visibility spectroscopy. During an avalanche, we find that the fluctuation speed is approximately one-tenth the average flow speed, deltav approximately equal to 0.1v , and that these speeds are largest near the beginning of an event. We also find that the distribution of event durations is peaked, and that event sizes are correlated with the time interval since the end of the previous event. At high rates of grain addition, where successive avalanches merge into smooth continuous flow, the relationship between average and fluctuation speeds changes to deltav approximately v(1/2) .

Determination of medullasin levels for the diagnosis of multiple sclerosis.

OBJECTIVES: To obtain a simple and reliable clinical parameter for the diagnosis of multiple sclerosis among patients with neurological diseases. PATIENTS AND METHODS: Heparinized peripheral blood was obtained from patients with multiple sclerosis and those with non-inflammatory neurological diseases and healthy volunteers. A new enzyme immunoassay method determining medullasin levels in human granulocytes was developed by using mouse monoclonal antibody against medullasin. RESULTS: A newly developed enzyme immunoassay method for medullasin can detect as little as 1 ng/ml medullasin and results can be obtained within 2 h. Eighty-five out of 112 patients with multiple sclerosis (75.8%) showed positive results (above means of normals + 2 SD) in the medullasin test, while 15.4% (12/78) of patients with non-inflammatory neurological disease had positive results. CONCLUSION: This newly developed enzyme immunoassay method for medullasin is considered to be a useful paraclinical test for the diagnosis of multiple sclerosis.

Chemiluminescent measurement of peroxidase activity and its application using a lucigenin CT-complex.

Luminol (3-aminophthaloylhydrazine) is well known as a chemiluminescent reagent that can be used to measure peroxidase (POD) activity. We have developed a more sensitive assay for POD using a new chemiluminescent reagent based on 10,10'-dimethyl-9, 9'-biacridinium nitrate (lucigenin). This new reagent was obtained from lucigenin by light irradiation in an organic polar solvent such as N,N-dimethylacetamide (DMAc). The detection limit for POD activity using this reagent is 10(-19) mol/assay. In an application for enzyme immunoassay based on a POD label, we were able to detect human alpha-fetoprotein (AFP) at 1pg/mL. The characterization of this chemiluminescent reagent was obtained by optical measurements, and the formation of lucigenin charge transfer complex (CT-complex) was confirmed. We also investigated the stability of lucigenin CT-complex as a chemiluminescent reagent for the measurement of POD activity, and confirmed that the reagent was stable for more than a year.

Distribution of metallothionein in cigarette smokers and non-smokers in advanced periodontitis patients.

This study evaluated the effect of smoking on periodontal tissue in periodontal patients. Gingival biopsies were taken from the flap during periodontal surgery of 33 male patients with advanced periodontal disease (22 cigarette smokers; 11 non-smokers). Frozen sections were made immediately and used for hematoxylin-eosin and Giemsa staining, and for detection of metallothionein (MT), a free radical scavenger. The expression and distribution of MT in these sections was studied using monoclonal antibody and immunohistochemical staining. The smokers had a large number of infiltrate cells in the gingival epithelium compared with non-smokers. Moreover, samples from the smokers showed high levels of MT in the prickle cell layer of the epithelium. In the non-smokers, basal and prickle cell layers of the gingival epithelium also showed detectable MT. Smokers, however, had a higher metallothionein-positive cell ratio in the prickle cell layer as compared to non-smokers. This increased level of MT in smokers may reflect an attempt to defend against free radicals in the gingiva of smokers. These results suggest that inflammation is much greater in periodontal tissues of cigarette smoking periodontal patients than in non-smoking periodontal patients, and that the defense against free radicals is heightened in smokers' gingiva.

Increase of heat-shock protein and induction of gamma/delta T cells in peritoneal exudate of mice after injection of live Fusobacterium nucleatum.

Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans are Gram-negative rod periodontal pathogens. The peritoneal cavity of Institute of Cancer Research (ICR) mice was used as the local infection model. In vivo production of heat-shock proteins (hsp) was studied by injection of 1/10 minimum lethal dose (MLD) of each live bacteria into mice. Heat-shock proteins 70 and 60 were examined in the extract of peritoneal exudate cells (PEC) from mice injected intraperitoneally with either F. nucleatum or A. actinomycetemcomitans by using sodium dodecylsulphate-polyacrylamide gel electrophoresis and immunoblotting analysis. Although hsp are present in PEC without injection of the bacteria, both hsp increased and reached a peak on day 3 after F. nucleatum injection but not after A. actinomycetemcomitans. Kinetic study of gamma/delta cells in PEC after injection of bacteria showed that the increase of gamma/delta T cells was observed only in the PEC from mice injected with F. nucleatum but not A. actinomycetemcomitans. The gamma/delta T cells in PEC were either CD3+ and CD4+ or CD3+ and CD8+. The differential cell count of PEC suggested that gamma/delta T-cell induction is related to the expansion of the macrophage population. The phagocytic and chemiluminescence responses of macrophages against the same bacteria were compared after intensive immunization with live F. nucleatum and A. actinomycetemcomitans. Elevations of chemiluminescence response and phagocytic function by immunization were observed in the macrophages of mice immunized with F. nucleatum. These results suggest the sequential appearance of hsp, gamma/delta T cells and macrophage activation after fusobacterial infection.

IgA-mediated inhibition of human leucocyte function by interference with Fc gamma and C3b receptors.

The inhibitory effects of IgA from human colostrum, and IgA1 and IgA2 from human serum on the chemiluminescence (CL) response and phagocytosis of polymorphonuclear leucocytes (PML) to Staphylococcus epidermidis and the CL response to formylmethionyl-leucyl-phenylalanine (FMLP) were studied. The dose-dependent inhibition of the luminol-mediated CL response of human PML to the bacteria was observed in the presence of more than 0.1 mg/ml IgA from both colostrum and serum. The preincubation of PML with a solution of IgA enhanced the suppressive effect of IgA on the cells. Removal of IgA from the reaction mixture after preincubation resulted in recovery, with time, of the response of PML to the bacteria. The bacteria treated with IgA did not give rise to any inhibition of the response. The CL response of PML to FMLP was not affected by the presence of IgA in the reaction mixture. The decrease of phagocytic activity of PML in the presence of IgA resulted in a decrease of NADPH oxidase activity of PML after stimulation with the bacteria as compared with the absence of IgA. The effect of IgA on the receptors of Fc and C3b (CR1) on the surface of PML was measured by monitoring erythrocyte-antibody (EA) or erythrocyte-antibody-complement (EAC) rosette formation and by direct and indirect immunofluorescence techniques using anti-CR1 antibody and Fc-specific antibodies. The presence of IgA in the reaction mixture led to a quantitative decrease in CR1 and the ability to bind IgG to the surface of PML.