Angiogenesis-dependent and independent phases of intimal hyperplasia.

BACKGROUND: Neointimal vascular smooth muscle cell (VSMC) proliferation is a primary cause of occlusive vascular disease, including atherosclerosis, restenosis after percutaneous interventions, and bypass graft stenosis. Angiogenesis is implicated in the progression of early atheromatous lesions in animal models, but its role in neointimal VSMC proliferation is undefined. Because percutaneous coronary interventions result in induction of periadventitial angiogenesis, we analyzed the role of this process in neointima formation. METHODS AND RESULTS: Local injury to the arterial wall in 2 different animal models induced periadventitial angiogenesis and neointima formation. Application of angiogenesis stimulators vascular endothelial growth factor (VEGF-A165) or a proline/arginine-rich peptide (PR39) to the adventitia of the injured artery induced a marked increase in neointimal thickening beyond that seen with injury alone in both in vivo models. Inhibition of either VEGF (with soluble VEGF receptor 1 [sFlt1]) or fibroblast growth factor (FGF) (with a dominant=negative form of FGF receptor 1 [FGF-R1DN]), respectively, signaling reduced adventitial thickening induced by VEGF and PR39 to the level seen with mechanical arterial injury alone. However, neither inhibitor was effective in preventing neointimal thickening after mechanical injury when administered in the absence of angiogenic growth factor. CONCLUSIONS: Our findings indicate that adventitial angiogenesis stimulates intimal thickening but does not initiate it

Energetic ion dynamics in Jupiter's plasma sheet

A systematic study of energetic ion trajectories in Jupiter's plasma sheet region predicts a significant role for both regular and stochastic types of motion and reveals several aspects of the ion dynamics that aid in the interpretation of Galileo observations. The motion is generally confined to the vicinity of the current sheet in a way that is proportional to the variable current sheet thickness as seen in the particle and field data. The radial extent of the trajectories increases with rigidity and initial radial distance from the planet, explaining the corresponding lack of high-rigidity ions and decreasing radial gradients at lower rigidity. Ion intensity increases associated with changes in current sheet thickness suggest an acceleration region at ∼25 to 30 R_J. Energy dispersion in ion events at larger radial distances can be explained by such a source combined with elastic ion scattering

Phytochrome modulation of calcium fluxes in wheat (Triticum aestivum L.) protoplasts

Employing the metallochromic dye murexide and by monitoring the uptake of radiolabelled calcium, photoreversible calcium fluxes were measured in wheat leaf protoplast suspensions. Results obtained by both methods were identical - red light promoted and subsequent far-red irradiation reversed an influx of Ca++ ions into the protoplasts. These findings imply phytochrome regulation of Ca++ fluxes across the plasma membrane. The influx of Ca++ stimulated by 2 min red irradiation could be maintained in total darkness for the initial 16-18 min after illumination, after which a 6-8 min efflux process was triggered and the basal Ca++ level restored. Verapamil, a calcium channel blocker, inhibited the red-promoted influx, whereas the far-red mediated efflux could be checked by the use of the ATPase inhibitor vanadate, and also by the calmodulin antagonist chlorpromazine, thus suggesting a role of ion channels and pumps in phytochrome-controlled Ca++ fluxes. The possible involvement of phosphoinositides in phytochrome-modulated calcium fluxes was also investigated

Co-existent extrapulmonary, extragenital tuberculosis and gynaecological tumours: a reminder to pathologists

Extrapulmonary and extragenital tuberculosis is rarely encountered along with gynaecological tumours or malignancy. This report presents a case series of gynaecological malignancies/tumors co-existing with extrapulmonary, extragenital tuberculosis. Pathologists should always stay open to this possibility. A high index of suspicion is needed in view of the HIV pandemic causing resurgence of tuberculosis especially in third world countries.

Environmental factors influencing aphid transmission of potato virus Y and potato leafroll virus

The effect of temperature, relative humidity (RH) and light on aphid transmission of potato virus Y (PVY) and potato leafroll virus (PLRV) was studied using as vectors Myzus persicae Sulz. and Aphis gossypii Glov. Host susceptibility was enhanced by 48 h pre-inoculation exposure at 25°C and by 48 h post-inoculation exposure to 30°C. High RH (80%) in both pre- or postinoculation phases enhanced host susceptibility. Continuous fluorescent light (4000 lux) did not alter the rate of transmission of either virus. High RH (80-90%) and high temperature (25-30°C), when combined, increased virus transmission by 30-35%. Transmission rates were reduced by nearly 50% if RH was maintained at 50% in either of the two phases even if the temperature was 25 or 30°C. Both viruses were acquired by aphids earlier (13-20 days after inoculation) when the source plants were incubated at 25 or 30°C. Most virus was transmitted from plants inoculated with PVY 13 to 16 days and with PLRV 15 to 20 days previously. Transmission rates of PVY were enumerated from symptom expression on test plants and by Enzyme Linked Immunosorbent Assay (ELISA) whereas those of PLRV were enumerated from symptom expression alone

Interchangeable punishments during aversive conditioning in Drosophila

Using Drosophila melanogaster larvae we asked whether distinct aversive stimuli have a common neuralrepresentation during associative learning. We tested the interchangeability of heat shock and electroshock punishments when used within a single olfactory associative conditioning experiment. We find that compared to animals trained with the repetitive use of a single punishment, the use of two alternating punishments results in similar associative learning. Additionally, the two punishments are shown to have different sensory origins. Therefore, while punishments are processed differently by the larvae of Drosophila melanogaster, the value of the stimulus is preserved

Nonlinear Optical Response Functions of Mott Insulators Based on Dynamical Mean Field Approximation

We investigate the nonlinear optical susceptibilities of Mott insulators with the dynamical mean field approximation. The two-photon absorption (TPA) and the third-harmonic generation (THG) spectra are calculated, and the classification by the types of coupling to external fields shows different behavior from conventional semiconductors. The direct transition terms are predominant both in the TPA and THG spectra, and the importance of taking all types of interaction with the external field into account is illustrated in connection with the THG spectrum and dcKerr effect. The dependence of the TPA and THG spectra on the Coulomb interaction indicate a scaling relation. We apply this relation to the quantitative evaluation and obtain results comparable to those of experiments.Comment: 14 pages, 12 figure

The role of plasma slowdown in the generation of Rhea's Alfven wings

Alfvén wings are known to form when a conducting or mass-loading object slows down a flowing plasma in its vicinity. Alfvén wings are not expected to be generated when an inert moon such as Rhea interacts with Saturn's magnetosphere, where the plasma impacting the moon is absorbed and the magnetic flux passes unimpeded through the moon. However, in two close polar passes of Rhea, Cassini clearly observed magnetic field signatures consistent with Alfvén wings. In addition, observations from a high-inclination flyby (Distance > 100 RRh) of Rhea on 3 June 2010 showed that the Alfvén wings continue to propagate away from Rhea even at this large distance. We have performed three-dimensional hybrid simulations of Rhea's interaction with Saturn's magnetosphere which show that the wake refilling process generates a plasma density gradient directed in the direction of corotating plasma. The resulting plasma pressure gradient exerts a force directed toward Rhea and slows down the plasma streaming into the wake along field lines. As on the same field lines, outside of the wake, the plasma continues to move close to its full speed, this differential motion of plasma bends the magnetic flux tubes, generating Alfvén wings in the wake. The current system excited by the Alfvén wings transfers momentum to the wake plasma extracting it from plasma outside the wake. Our work demonstrates that Alfvén wings can be excited even when a moon does not possess a conducting exosphere

DYNAMIC APPROACH TO k-Means CLUSTERING ALGORITHM

ABSTRACT k-Means clustering algorithm is a heuristic algorithm that partitions the dataset into k clusters by minimizing the sum of squared distance in each cluster. In contrast, there are number of weaknesses. First it requires a prior knowledge of cluster number 'k'. Second it is sensitive to initialization which leads to random solutions. This paper presents a new approach to k-Means clustering by providing a solution to initial selection of cluster centroids and a dynamic approach based on silhouette validity index. Instead of running the algorithm for different values of k, the user need to give only initial value of k as k o as input and algorithm itself determines the right number of clusters for a given dataset. The algorithm is implemented in the MATLAB R2009b and results are compared with the original k-Means algorithm and other modified k-Means clustering algorithms. The experimental results demonstrate that our proposed scheme improves the initial center selection and overall computation time