Heat transfer enhancement by coated fins in the microscale domain

Micro-fins configuration is considered as a capable cooling method for microelectronic components due to its space optimization and types of heat transfer. In this study micro-fins profile is selected according to the type of heat transfer and fabricated on copper and aluminum materials through wire-cut electric discharge machining process. The four numbers of square test pieces of dimensions of 4.5 cm × 4.5 cm and fin height, H, of 0.25 mm with different spacing, S, of 3.75 mm and 5 mm are considered for the experimentation. The fabricated test pieces such as aluminum, copper, painted aluminum, and painted copper are used in this experiments. This paper aims to improve the convective heat transfer coefficient by applying aluminum paint coating on a micro-fin structure. The paint coated copper test piece produces 20.62% higher heat transfer compared to aluminum test piece. On comparing the aluminum with aluminum paint coated test piece, the convective heat transfer rate found to increase by 49%. Coated aluminum test piece with 3.75 mm and 5 mm spacing shows higher radiation heat transfer compared to other micro-fin structures

The flexible C terminus of the rotavirus non-structural protein NSP4 is an important determinant of its biological properties

The rotavirus non-structural protein NSP4 functions as the viral enterotoxin and intracellular receptor for the double-layered particles (DLP). The full-length protein cannot be expressed and/or purified to homogeneity from bacterial or insect cells. However, a bacterially expressed and purified mutant lacking the N-terminal 72 aa(\triangle N72) was recently obtained from strains Hg18 and SA11 exhibiting approximately 17–20-, 150–200- and 13166–15800-fold lower $DD_{50}$ (50% diarrhoea-inducing dose) values in suckling mice compared with that reported for the partially pure, full-length protein, a C-terminal M175I mutant and a synthetic peptide comprising aa 114– 135, respectively, suggesting the requirement for a unique conformation for optimal functions of the purified protein. The stretch of approximately 40 aa from the C terminus of the cytoplasmic tail of the endoplasmic reticulum-anchored NSP4 is highly flexible and exhibits high sequence variation compared with the other regions, the significance of which in diarrhoea induction remain unresolved. Here, it was shown that every amino acid substitution or deletion in the flexible C terminus resulted in altered conformation, multimerization, trypsin resistance and thioflavin T (ThT)binding, and affected DLP binding and the diarrhoea-inducing ability of the highly diarrhoeagenic SA11 and Hg18 $\triangle$N72 in suckling mice. These studies further revealed that high ThT fluorescence correlated with efficient diarrhoea induction, suggesting the importance of an optimal ThT-recognizable conformation in diarrhoea induction by purified NSP4. These results based on biological properties provide a possible conformational basis for understanding the influence of primary sequence variations on diarrhoea induction in newborn mice by purified NSP4s that cannot be explained by extensive sequence analyses

Crystallographic and Receptor Binding Characterization of Plasmodium falciparum Macrophage Migration Inhibitory Factor Complexed to Two Potent Inhibitors

We report the crystal structures of two inhibitors of Plasmodium falciparum macrophage migration inhibitory factor (<i>Pf</i>MIF) with nanomolar <i>K</i>_i’s, analyze their interactions with the active site of <i>Pf</i>MIF, and provide explanations regarding their selectivity of <i>Pf</i>MIF versus human MIF. These inhibitors were also found to selectively inhibit interactions between <i>Pf</i>MIF and the human MIF receptor CD74. The results of this study provide the framework for the development of new therapeutics that target <i>Pf</i>MIF

A Model of GAG/MIP-2/CXCR2 Interfaces and Its Functional Effects

MIP-2/CXCL2 is a murine chemokine related to human chemokines that possesses the Glu-Leu-Arg (ELR) activation motif and activates CXCR2 for neutrophil chemotaxis. We determined the structure of MIP-2 to 1.9 Å resolution and created a model with its murine receptor CXCR2 based on the coordinates of human CXCR4. Chemokine-induced migration of cells through specific G-protein coupled receptors is regulated by glycosaminoglycans (GAGs) that oligomerize chemokines. MIP-2 GAG-binding residues were identified that interact with heparin disaccharide I–S by NMR spectroscopy. A model GAG/MIP-2/CXCR2 complex that supports a 2:2 complex between chemokine and receptor was created. Mutants of these disaccharide-binding residues were made and tested for heparin binding, in vitro neutrophil chemotaxis, and in vivo neutrophil recruitment to the mouse peritoneum and lung. The mutants have a 10-fold decrease in neutrophil chemotaxis in vitro. There is no difference in neutrophil recruitment between wild-type MIP-2 and mutants in the peritoneum, but all activity of the mutants is lost in the lung, supporting the concept that GAG regulation of chemokines is tissue-dependent