ALBERT

Description: Kallistatin has been recognized as an endogenous angiogenic inhibitor. However, the underlying molecular mechanism remains poorly understood. Taking it into account that vascular endothelial growth factor (VEGF) has been implicated in all aspects of normal and pathological vasculogenesis and angiogenesis, in this study, we investigated whether VEGF signaling pathway was impacted by the anti-angiogenic effect of recombinant human kallistatin (rhKal). It has been found the rhKal inhibited proliferation as well as induced apoptosis of cultured human umbilical vein endothelial cells (HUVECs) in both concentration- and time-dependent manners. The rhKal also suppressed the VEGF-induced migration and tube formation of HUVECs. Furthermore, our data revealed that the rhKal suppressed the VEGF165-stimulated tyrosine phosphorylation of VEGFR-2 as well as its downstream signal molecular activation. The inhibition of receptor phosphorylation was correlated with a decrease in VEGF-triggered phosphorylation of angiogenesis signal molecules AKT and ERK, but not stress-related JNK. Taken together, these findings added the knowledge for us to understand the anti-angiogenic mechanism of kallistatin, which suggested that the rhKal could be worth as a candidate compound for further development for the purpose of anti-angiogenic therapies. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.

Description: Abstract At the core‐mantle boundary, most observed ultra‐low velocity zones (ULVZ's) cluster along the edges of the large low shear velocity provinces (LLSVP's) and provide key information on the composition, dynamics and evolution of the lower mantle. However, their detailed structure near slab‐like structures beneath the mid‐Pacific remains particularly challenging because of the lack of station coverage. While most studies of ULVZ's concentrate on SKS‐complexity, here we report on the multi‐pathing of ScS which expands the sampling for ULVZ's. We find the strongest multi‐pathing along a ULVZ patch located just south of Hawaii and the far northeastern edge of the LLSVP, in a zone ~200 km in width and extending 600 km southward. The anomalous ScS travel times and distorted Sdiff waveforms further reveal patches interrupted by observed enhanced D" indicative of slab‐debris influence on the complexity of the northeastern boundary of the mid‐Pacific LLSVP.

Description: During the first several months of the three-spacecraft Swarm mission all three spacecraft came repeatedly into close alignment, providing an ideal opportunity for validating the proposed dual spacecraft method for estimating current density from the Swarm magnetic field data. Two of the Swarm spacecraft regularly fly side-by-side in closely similar orbits, while the third at times approaches the other two. This provides a data set which under certain assumptions of stationarity of the magnetic field, can produce 2, 3, 4, 5 (or more) point measurements, which can be cross-compared. We find that at low Earth orbit the use of time-shifted positions allow stable estimates of current density to be made and can verify temporal effects as well as validating the interpretation of the current components as arising predominantly from field aligned currents. In the case of four-spacecraft configurations we can resolve the full vector current and therefore can check the perpendicular as well as parallel current density components directly, together with the quality factor for the estimates directly (for the first time in situ at low earth orbit).

Description: [1]  During the interval ~07:45:36–07:54:24UT on 24 August 2005, Cluster satellites (C1 and C3) observed an obvious loss of energetic electrons (~3.2-95 keV) associated with the growth of whistler mode waves inside some bursty bulk flows (BBFs) in the midtail plasma sheet ( X GSM  ~ −17.25R E ). However, the fluxes of the higher-energy electrons (≥128 keV) and energetic ions (10-160 keV) were relatively stable in the BBF-impacted regions. The energy-dependent electron loss inside the BBFs is mainly due to the energy-selective pitch angle scatterings by the whistler mode waves within the scattering time scales from several seconds to several minutes, and the pitch angle evolutions of the resonant electrons in different initial distributions are different in the wave growth regions. The low-energy plasma sheet electrons (~0.073-2.1 keV) have initially a field-aligned pitch angle distribution (0 o  ≤  α  ≤ 30 o and 150 o  ≤  α  ≤ 180 o ) in the absence of the whistler mode waves, and the loss of the low-energy electrons in field-aligned directions is accompanied by their increase in quasi-perpendicular directions (30 o  〈  α  〈 150 o ) in the intense wave growth regions inside the BBFs, indicating that the resonant electrons in a field-aligned pitch angle distribution can be scattered by the waves simultaneously into the loss cone and towards the larger pitch-angles. Due to the limits of the small loss cone ( α c  ~ 0.8-1.3 o ) and double-direction scatterings in field-aligned distributions, the loss of the low-energy electrons inside the BBFs is not obvious in the presence of their large background fluxes. Unlike the low-energy electrons, the plasma sheet energetic electrons (~3.2-95 keV) have mainly a quasi-perpendicular pitch angle distribution (30 o  〈  α  〈 150 o ) during the expansion-to-recovery development of a substorm ( AE index decreased from 1677nT to 1271nT), and their loss can occur at almost all pitch angles in the intense wave growth regions inside the BBFs, indicating that the resonant electrons in a quasi-perpendicular pitch angle distribution are always scattered by the waves from the larger pitch angles to the loss cone. Finally, the growth of whistler mode waves causes the net loss of the quasi-perpendicular distribution electrons inside the BBFs. These observations indicate that the anisotropic distribution energetic electrons mainly undergo the rapid pitch angle scattering loss because of the growth of whistler mode waves inside the BBFs with a highly compressed equatorial magnetic field (~tens of nT), but the final loss effect of the wave-induced pitch angle scatterings on resonant electrons depends on their initial pitch angle distributions.

Description: At the core-mantle boundary, most observed ultralow velocity zones (ULVZs) cluster along the edges of the large low shear velocity provinces (LLSVPs) and provide key information on the composition, dynamics, and evolution of the lower mantle. However, their detailed structure near slab-like structures beneath the mid-Pacific remains particularly challenging because of the lack of station coverage. While most studies of ULVZs concentrate on SKS-complexity, here we report on the multipathing of ScS, which expands the sampling for ULVZs. We find the strongest multipathing along a ULVZ patch located just south of Hawaii and the far northeastern edge of the LLSVP, in a zone ~200 km in width and extending 600 km southward. The anomalous ScS travel times and distorted Sdiff waveforms further reveal patches interrupted by observed enhanced D″ indicative of slab-debris influence on the complexity of the northeastern boundary of the mid-Pacific LLSVP. ©2019. American Geophysical Union. All Rights Reserved.