5,849 research outputs found
Stability Constants of Some Transition Metal Complexes with Schiff Bases Derived from Salicylaldehyde & m-Aminophenol or m-Anisidine
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Geochemistry of some ferruginous soils of Kerala, India
The four representative ferruginous soils on lateritic cover developed over Precambrian rocks in parts of Kottayam of Kerala were studied to understand the weathering pattern and genesis through geochemistry. These soils are strongly to moderately acidic, reddish brown with low Cation exchange capacity CEC and base saturation having SiO2 - 33 to 57%, Al2O3 - 16-31%, Fe2O3 - 8 to 15% and TiO2 -0.7 to 1.4%. Kanjirapalli (P3) and Athirampuzha (P4) soil series were more intensely weathered as compared to the Kinalur (P1) and Chingavanam series (P2) with silica to alumina -iron ratio less than 2 and had a significant negative relationship with Chemical index of alteration CIA ( -0.75**), Harnois index ( -0.678**), Richie index (-0.953**) and Plagioclase Index of Weathering (-0.705**). The trace elemental concentration ranges were above the values of world soils having an enrichment index more than 1 in Kanjirapalli series (P3) and Ni contamination in genetic horizons (Ni > 200µgg-1 ). The cluster analysis showed similar major oxide concentration pattern in Group -1 and Group - 2 but varied in trace elemental pattern with Cr > Ba > Cu in Group - 1 and Cu > Cr > Ba in Group- 2 soils whereas Zr > Ni > Mn in Group - 3 to Ni > Mn > Zr in Group - 4 soils. The study further showed that differential rate of weathering in soils under tropical climate was further accelerated due to anthropogenic activities such as improper land use practices and deforestation on sleep slopes
Interactions between fibroblastic reticular cells and B cells promote mesenteric lymph node lymphangiogenesis.
Lymphatic growth (lymphangiogenesis) within lymph nodes functions to promote dendritic cell entry and effector lymphocyte egress in response to infection or inflammation. Here we demonstrate a crucial role for lymphotoxin-beta receptor (LTβR) signaling to fibroblastic reticular cells (FRCs) by lymphotoxin-expressing B cells in driving mesenteric lymph node lymphangiogenesis following helminth infection. LTβR ligation on fibroblastic reticular cells leads to the production of B-cell-activating factor (BAFF), which synergized with interleukin-4 (IL-4) to promote the production of the lymphangiogenic factors, vascular endothelial growth factors (VEGF)-A and VEGF-C, by B cells. In addition, the BAFF-IL-4 synergy augments expression of lymphotoxin by antigen-activated B cells, promoting further B cell-fibroblastic reticular cell interactions. These results underlie the importance of lymphotoxin-dependent B cell-FRC cross talk in driving the expansion of lymphatic networks that function to promote and maintain immune responsiveness.The growth of lymph nodes in response to infection requires lymphangiogenesis. Dubey et al. show that the mesenteric lymph node lymphangiogenesis upon helminth infection depends on the signaling loop between the B and fibroblastic reticular cells (FRCs), whereby the FRCs respond to lymphotoxin secreted by B cells by releasing B cell activating factor
Sustainability of crop production from polluted lands
Sustainable food production for a rapidly growing global population is a major challenge of this century. In order to meet the demand for food production, an additional land area of 2.7 to 4.9 Mha year -1 will be required for agriculture. However, one third of arable lands are already contaminated, therefore the use of polluted lands will have to feature highly in modern agriculture. The use of such lands comes however with additional challenges and suitable agrotechnological interventions are essential for ensuring the safety and sustainability of relevant production system. There are also other issues to consider such as, cost benefit analysis, the possible entry of pollutants into to the phytoproducts, certification and marketing of such products, in order to achieve a the large scale exploitation of polluted land
Collisions of micron-sized, charged water droplets in still air
We investigate the effect of electrical charge on collisions of
hydrodynamically interacting, micron-sized water droplets settling through
quiescent air. The relative dynamics of charged droplets is determined by
hydrodynamic interactions, particle and fluid inertia, and electrostatic
forces. We analyse the resulting relative dynamics of oppositely charged
droplets by determining its fixed points and their stable and unstable
manifolds. The stable manifold of a saddle point forms a separatrix that
separates colliding trajectories from those that do not collide. The
qualitative conclusions from this theory are in excellent agreement with
experiments.Comment: 6 pages, 2 figures, supplemental materia
Development of low tungsten substitute tool steels
Tunsten is a very important alloying element in high
speed tool steel, hot and cold work die steel and permanent magnet alloys, but its ore deposits are
limited to a few countries. Continuous development
user the years to reduce tungsten content in convent-
ional 18-4-1 high speed steel i.e. 18% tungsten, 1% chromium and 1% vanadium, has led to increase of molybdenum, cobalt, chromium or vanadium. These
steels have a hyper eutectoid structure in the fully
hardened state in which complex carbides are embedded
in martensite matrix. Both of these constituents in
high speed steel retain higher hardness at high
temperature than their counterpart in plain carbon
steel. Many such high speed steels with low amount or without tungsten have been developed. These low tung-
sten steels' apart from replacing the non-available alloying elements have the additional advantage of requiring lower hardening temperature than high speed
tool steel containing 18% tungsten, thus avoiding the formation of coarse grain size in steel
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