Conjugate mixed convection heat and mass transfer in brick drying

 In this study, a numerical methodology for the solution of conjugate heat and mass transfer problem is presented. Fluid flow, heat and mass transfer over a rectangular brick due to transient laminar mixed convection has been numerically simulated. The coupled non-linear partial differential equations, for both gas phase and solid are solved using finite element procedure. Flow is assumed to be incompressible, two-dimensional, laminar. Analysis has been carried out at a Reynolds number of 200 with Pr = 0.71. The effect of buoyancy on the brick drying has been investigated. Velocity vectors, streamlines in the flow field and temperature and moisture contours and temperature distribution along the solid surface are presented. It is observed that there is considerable effect of buoyancy during drying. The results indicate a non-uniform drying of the brick with the leading edge drying faster than the rest of the brick. Received on 9 December 1998     

In situ catalyst systems for ring-opening metathesis polymerization

Several new in situ tungsten catalyst systems for ring-opening metathesis polymerizations (ROMP) by reaction injection molding (RIM) have been developed by adding BF₃ promoter to binary catalyst systems, by using metal hydride cocatalysts, and by altering the ligands on the procatalyst metal center. BF₃ etherates improved catalyst efficiency and reduced induction times for formation of active catalysts from reaction of aryloxytungsten complexes [e.g., (ArO)_y(WX_x)] with organotin hydrides. Coordinatively unsaturated cationic intermediates, such as [(ArO)_yWX_x-1]⁺ BF₃X⁻, are proposed to facilitate formation of the active catalysts. Tougher poly(dicyclopentadiene) (polyDCPD) composites were produced using < 5 wt % of styrene-butadiene block copolymers due to formation of small “shell-core” rubber morphologies when BF₃ promoter was added to the catalyst system. Nonalkylating metal hydrides besides R₃SnH, including (PPh₃)₂CuBH₄, (PPh₃CuH)₆, and Cp₂ZrClH, were shown to be cocatalysts. The optimum 2 : 1 stoichiometric ratio of organotin hydride cocatalyst to tungsten, revealed by BF₃-promoted catalyst systems, and W^V EPR resonances (g ∼ 1.7) observed in the reaction of aryloxytungsten with organotin hydride are consistent with an overall reduction and reoxidation mechanism for formation of the active metathesis catalysts. Some tungsten complexes derived from 9-hydroxyfluorene, 2,2′-(and 4,4′)-biphenols, and 1,4-hydroquinones were found to be very reactive procatalysts, even in the absence of cocatalyst in some cases. These procatalysts also were paramagnetic, characterized by unusual EPR spectra consistent with W^V (g = 1.6–1.9) and “ligand-centered” (g = 2.003) resonances. Valence tautomeric species, analogous to catecholate-semiquinonate complexes, are proposed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3027–3047, 1997     

Mineralization of oriented nano hydroxyapatite in photopolymerized polyacrylamide gel matrix

Polyacrylamide hydrogel is a biomaterial and nondegradable water based polymer which is used as tissue filler. Mineralization of hydroxyapatite (HAp) in a UV polymerized acrylamide gel matrix was investigated by varying the concentration of precursors and pH in the range 8, 9 and 10. During polymerization, diammonium hydrogen phosphate ions were impregnated in the gel matrix and subsequently, immersed in the calcium nitrate solution. Thin laminated macroporous structures, embedded with nanospheres and ribbons of HAp were mineralized. The HAp was found to be oriented along c‐axis, which could lead to the preferential binding of the acidic proteins on it's surface. In addition, there was an enlargement of pore sizes with an increase in pH. The laminated structures showed resorbable nature whereas, flake like structures obtained at higher concentrations were found to be bioactive. This composite could be an alternative to the use of silicone gel, to avoid long term risk of fibrosis and migration when implanted. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

An Investigation on the Lattice Distortion in Urea and KCl Doped KDP Single Crystals by X‐ray Diffraction Studies

Potassium dihydrogen phosphate (KDP) doped with different mole concentrations of Urea and KCl were grown using low temperature solution growth technique. X‐ray diffraction studies were carried out on the grown crystals using a Shimadzu X‐ray diffractometer with CuKD radiation. X‐ray study revealed that the structures of the doped crystals are slightly distorted compared to the pure KDP crystal. This may be attributed to strains on the lattice by the adsorption of urea and KCl.     

Targeted Protein Upregulation of STING for Boosting the Efficacy of Immunotherapy

Modulating target proteins via the ubiquitin-proteasome system has recently expanded the scope of pharmacological inventions. Stimulator of interferon genes (STING) is an auspicious target for immunotherapy. Seminal studies envisioned the importance of STING as well as the utility of its agonists in immunotherapy outcomes. Herein, we suggest UPPRIS (upregulation of target proteins by protein-protein interaction strategy) to pharmacologically increase cellular STING levels for improved immunotherapy. We discovered the small molecule SB24011 that inhibits STING-TRIM29 E3 ligase interaction, thus blocking TRIM29-induced degradation of STING. SB24011 enhanced STING immunity by upregulating STING protein levels, which robustly potentiated the immunotherapy efficacy of STING agonist and anti-PD-1 antibody via systemic anticancer immunity. Overall, we demonstrated that targeted protein upregulation of STING can be a promising approach for immuno-oncology.