Numerical investigation of flow boiling characteristics of water in a rectangular microchannel

Journal of Thermal Analysis and Calorimetry - In the case of flow boiling, the prediction of vapour fraction in the horizontal microchannel is a severe issue using the numerical technique....     

Thermal studies on yttrium,neodymium and holmium oxalates

The thermal decomposition patterns of Y₂(C₂O₄)₃ · 9 H₂O, Nd₂(C₂O₄)₃ · 10 H₂O and Ho₂(C₂O₄)₃ · 5.5 H₂O have been studied using TG and DTG. The hydrated neodymium oxalate loses all the water of hydration in one step to give the anhydrous oxalate while Y₂(C₂O₄)₃ · 9 H₂O and Ho₂(C₂O₄)₃ · 5.5 H₂O involve four or more dehydration steps to yield the anhydrous oxalates. Further heating of the anhydrous oxalates results in the loss of CO₂ and CO to give the stable metal oxides.     

Thermal studies on dithionate compounds

TG and DTG studies have been carried out on CoS₂O₆ · 6H₂O, NiS₂O₆ · 6 H₂O, CuS₂O₆ · 3.5 H₂O, ZnS₂O₆ · 6 H₂O and CdS₂O₆ · 4H₂O. After partial dehydration, the dithionates of Co(II), Ni(II), Cu(II) and Zn(II) lose water and sulfur dioxide simultaneously to yield the stable metal sulfates in the final step of decomposition. The CdS₂O₆ · 4H₂O dehydrates completely in the first two steps of decomposition with two water molecules being lost in each step. In the third step, it loses only SO₂ to yield CdSO₄. Kinetic parameters are presented for these reactions.

---

Zusammenfassung TG- und DTG-Untersuchungen von CoS₂O₆ · 4 H₂O, NiS₂O₆ · 6 H₂O, CuS₂O₆ · 3.5 H₂O, ZnS₂O₆ · 6 H₂O und CdS₂O₆ · 4 H₂O wurden ausgeführt. Nach partieller Dehydratisierung geben die Dithionate von Co(II), Ni(II), Cu(II) und Zn(II) im letzten Schritt des Abbaus gleichzeitig Wasser und Schwefeldioxid unter Bildung der stabilen Metallsulfate ab. CdS₂O₆ · 4 H₂O wird in den ersten beiden Zersetzungsschritten unter Abgabe von je 2 Wassermolekülen vollständing zersetzt. Im dritten Schritt wird nur SO₂ unter Bildung von CdSO₄ abgegeben. Kinetische Parameter dieser Reaktionen werden angegeben.

---

CoS₂O₆ · 6 H₂O, NiS₂O₆ · 6 H₂O, CuS₂O₆ · 3.5 H₂O, ZnS₂O₆ · 6 H₂O CdS₂O₆ · 4 H₂O. , , , , . , . , . .

     

Defense role of the cocoon in the silk worm Bombyx mori L

Silk from the domesticated silk worm Bombyx mori procures foreign body response naturally, so it has been utilized as a biomaterial for decades. In India the prime focus of the sericulture industry is to improve silk production with high quality silk. Naturally, the silk worm builds its cocoon not only with silk proteins, but also with antimicrobial proteins to avoid infection since the cocoon is non-motile and non-feeding. The aim of the present study is to elucidate the antimicrobial proteins that persist in the cocoon of the silk worm Bombyx mori. At the pupal stage, the silk worm cocoon shell extract was prepared from the day of pupation (P0) to the day of natural rupture of the cocoon for the eclosion of moth (NR). Using the cocoon shell extract a microbial susceptibility test was performed by the disc diffusion method against the microbes Escherchia coli, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The development of a zone of inhibition against the microbes confirmed the presence of antimicrobial/immunogenic activity of the cocoon shell extract. For further analysis, the cocoon shell extract was subjected to 7-15% sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE). The protein profile of the cocoon extract revealed the coomassie blue stained bands resolved from the 150-15 kDa molecular range. Interestingly, a polypeptide localized at around 29 kDa showed remarkable expressional changes during the development of pupa. To characterize the 29 kDa protein, it was eluted from the gel, digested with trypsin and analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The trypsin-digested peptide peaks were analyzed through MASCOT and peptides were matched with the NCBI nr database. The peptides were very well matched with the 18 wheeler protein, which is reported to be responsible for innate immunity, belonging to the Toll family in insects and responsible for cellular mediated immunity.     

Evaluation of fuels for the synthesis of Li2CoMn3O8

Li₂CoMn₃O₈, a 5 V cathode material used in rechargeable lithium batteries, has been synthesized by adopting a novel technique of using fuels along with the nitrate reactants. The effect of the fuel on the synthesis of Li₂CoMn₃O₈ has been analyzed in terms of the physical and electrochemical properties of the final product formed by various methods such as solid-state carbonate fusion and the solution route using acetate and nitrate precursors. Powder X-ray diffraction FT IR spectrum, particle size, surface area and SEM analysis were carried out. The combustion method, also known as selfpropagating high temperature (SPHT) method, has been employed in the present study by using nitrate mixtures of the respective salts and a nitrogeneous fuel (urea or glycine) at a temperature of 300 °C for 3 hrs. The nitrate reactants without the addition of fuel gave only a deliquescent product even at elevated temperature (600 °C) thus indicating the necessity of fuels. Similar attempts using acetate reactants with and without the addition of nitrogeneous fuels were made separately in order to find out the necessity of fuel also in this case. The characterization of the product in terms of purity, single-phase formation and surface morphology suggested that the fuel played no role in the case of the acetate precursors. A comparative study was made on the products obtained by the acetate precursor, combustion method and the conventional carbonate method. Among the three methods, the combustion method with glycine as fuel yielded the spinel phase with high purity Li₂CoMn₃O₈ with superior electrochemical behavior both in terms of high cell voltage and good cycle life behavior.     

Thermal studies on dithionate compounds. II. Dithionates of lithium, sodium, and magnesium

The decomposition of Li₂S₂O₆·2 H₂O, Na₂S₂O₆·2 H₂O, and MgS₂O₆·7 H₂O has been studied using TG and DTG. Both sodium and lithium dithionates dehydrate in one step. Magnesium dithionate dehydrates in three separate steps. All three of the dithionates undergo further decomposition and lose sulfur dioxide to give stable sulfates. Kinetic parameters are presented for these reactions.     

A convenient route for the synthesis of s,s-and R,R-warfarin alcohols

S,S-and R,R-warfarin alcohols 3 are prepared in good yield and in 99% d.e. (diastereomeric excess) by the reaction of S- or R-warfarin 1 with S or R-Alpine-Hidride 2.     

Synthesis of nucleopeptides by employing an enzyme-labile urethane protecting group

Nucleoproteins are naturally occurring biopolymers in which the hydroxy group of a serine, a threonine, or a tyrosine moiety is linked through a phosphodiester group to the 3'- or 5'-end of a nucleic acid. For the study of the biological phenomena in which nucleoproteins are involved, for example, viral replication, nucleopeptides embodying the characteristic linkage between the peptide chain and the oligonucleotide may serve as powerful tools. However, as a result of the multifunctionality and the pronounced acid and base lability of nucleopeptides, their synthesis requires the application of a variety of orthogonally stable blocking groups, which can be removed under the mildest conditions. We have developed a new mild enzymatic deprotection method, that is, the penicillin G acylase-catalyzed hydrolysis of the N-phenylacetoxybenzyloxycarbony (PhAcOZ) group, for the synthesis of nucleopeptides. We demonstrate the wide applicability of this method by coupling the N-terminally deprotected nucleopeptides 31 a-c with PhAcOZ-protected amino acids and subsequent removal of the N-PhAcOZ group from fully protected nucleotetrapeptides 32 a,b with penicillin G acylase. The reaction conditions are very mild (pH 6.8) so that no undesired side reaction such as cleavage of the nucleotide bond or beta-elimination of the nucleotide was observed.