Boiling heat transfer enhancement by nano-particles-assembled bi-porous layers

Nanoparticles-assembled bi-porous structure is newly proposed as boiling heat transfer enhancement technique. In order to assemble nanoparticles onto a heat transfer surface as a thin layer, a boiling adhesion method (BAM) is originally introduced in which, water or water/ethanol solution with mono-dispersed nanoparticles is dropped or sprayed onto a high temperature surface, and then the nanoparticles deposit onto the heat transfer surface during the boiling. In addition to that, it is expected that boiling bubbles can produce micro or milli scale of larger pores at the same time, which enables to fabricate bi-porous structure. Please download the full abstract below

CD11a regulates hematopoietic stem and progenitor cells

Integrin αLβ2 (CD11a/CD18, CD11a) is a critical leukocyte adhesion molecule in leukocyte arrest and immunological synapse formation. However, its role in the bone marrow has not been investigated in depth. Here we showed that CD11a was expressed on all subsets of hematopoietic stem and progenitor cells (HPSCs). CD11a deficiency enhanced HSPCs activity under lipopolysaccharide (LPS) stimulation as demonstrated by a higher HSPC cell count along with an increase in cell proliferation. However, our mixed chimera experiment did not support that this phenotype was driven in a cell-intrinsic manner. Rather we found that the production of IL-27, a major cytokine that drives HSPC proliferation, was significantly upregulated both in vivo and in vitro. This adds a novel role of CD11a biology

Application of nanoparticles-assembled bi-porous structures to power electronics cooling

Nanoparticles-assembled bi-porous structure is newly proposed and its potential to enhance the boiling heat transfer is evaluated in order to develop a new cooling device toward 300W/cm2 of on-vehicle inverter cooling. In order to assemble nanoparticles on to a heat transfer surface as a thin layer, a boiling adhesion method (BAM) is originally introduced in which, water or water/ethanol solution with mono-dispersed nanoparticles is dropped or sprayed onto a high temperature surface, and then the nanoparticles deposit onto the heat transfer surface during the boiling. In addition to that, it is expected that boiling bubbles can produce micro or milli scale of pores at the same time. In order to evaluate the applicability of the nanoparticles-assembled bi-porous structures, droplet behavior on a high temperature surface is visualized with a high speed camera The experimental results show that the boiling adhesion method can produce multi-scale pore structures composed of nano-scale pores and micro-scale pores and that the water droplet intensely boils and evaporates on a high temperature of a wall with nanoparticles-assembled bi-porous layer even under Leidenfrost conditions, which proves that the nanoparticles-assembled bi-porous structure enables the increase in both the critical heat flux and the boiling heat transfer in a nucleate boiling regim

An internal ligand-bound, metastable state of a leukocyte integrin, αXβ2

How is massive conformational change in integrins achieved on a rapid timescale? We report crystal structures of a metastable, putative transition state of integrin αXβ2. The αXβ2 ectodomain is bent; however, a lattice contact stabilizes its ligand-binding αI domain in a high affinity, open conformation. Much of the αI α7 helix unwinds, loses contact with the αI domain, and reshapes to form an internal ligand that binds to the interface between the β propeller and βI domains. Lift-off of the αI domain above this platform enables a range of extensional and rotational motions without precedent in allosteric machines. Movements of secondary structure elements in the β2 βI domain occur in an order different than in β3 integrins, showing that integrin β subunits can be specialized to assume different intermediate states between closed and open. Mutations demonstrate that the structure trapped here is metastable and can enable rapid equilibration between bent and extended-open integrin conformations and up-regulation of leukocyte adhesiveness

Communication—Alkyl-Chain-Length Dependence of Quaternary Ammonium Cation on Zn Deposition Morphology in Alkaline-Based Electrolytes

ArticleJournal of The Electrochemical Society. 166(10): A2242 (2019)journal articl