Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the ...

Imperial College London

The chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and II) make up the most conserved subfamily of nuclear receptors that play key roles in angiogenesis, neuronal development, organogenesis, cell fate determination, and metabolic homeostasis. Although the biological functions of COUP-TFs have been studied extensively, little is known of their structural features or aspects of ligand regulation. Here we report the ligand-free 1.48 A crystal structure of the human COUP-TFII ligand-binding domain. The structure reveals an autorepressed conformation of the receptor, where helix alpha10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. In contrast, in multiple cell lines, COUP-TFII exhibits constitutive transcriptional activity, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, and ligand binding, substantially reduce the COUP-TFII transcriptional activity. Importantly, retinoid acids are able to promote COUP-TFII to recruit coactivators and activate a COUP-TF reporter construct. Although the concentration needed is higher than the physiological levels of retinoic acids, these findings demonstrate that COUP-TFII is a ligand-regulated nuclear receptor, in which ligands activate the receptor by releasing it from the autorepressed conformation.

Identification of COUP-TFII orphan nuclear receptor as a retinoic acid-activated receptor.

The reactions of isolable dialkylsilylene 10 with various aldimines proceed smoothly at low temperatures to give diverse products depending on the substituents on the imine. The reactions of 10 with 4-XC(6)H(4)CH=NPh [X = H (11a), MeO (11b), and Cl (11c)] give the corresponding silaaziridines 12a-12c in high yields, which are thermally very stable and remain intact in the air and moisture for a long time. In contrast, the reactions of 10 with 4-F(3)CC(6)H(4)CH=NPh (11d) and 3,5-(F(3)C)(2)C(6)H(3)CH=NPh (11e) having strong electron-withdrawing aryl substituents on imine carbon are accompanied by 1,2-trimethylsilyl migration rather unexpectedly to give silaazetidines 13d-13e incorporated into a bicyclo[3.2.0]heptane ring. The reaction of 10 with N-benzylbenzaldimine 11f affords the corresponding (dibenzylamino)silane 14f in a moderate yield. Molecular structures of 12a-12c, 13d-13e and 14f were determined by X-ray crystallography. All these reactions are proposed to occur via the initial formation of the corresponding imine silaylides, while the subsequent reactions leading to the final products are controlled by the electronic structure of the ylide depending on the substituents. N-phenylbenzophenimine 11g does not react with 10.

Diverse reactivity of an isolable dialkylsilylene toward imines.

The 1 : 2 reactions of isolable dialkylsilylene with nitriles having electron-donating aromatic substituents gave 1,4-diaza-2-siloles with a hitherto-unknown type of ring system, in contrast to the previous studies showing exclusive formation of the corresponding 1,3-diaza-2-siloles; the reactions of with aromatic nitriles bearing electron-withdrawing substituents afforded the latter ring system. The remarkable diversity of the reactions is explained by invoking the corresponding nitrile silaylides as key intermediates whose polarity switches depending on the substituents of nitriles.

Reactions of an isolable dialkylsilylene with aromatic nitriles providing a new type of heterosilole.

To prepare recombinant human retinol binding protein 4 (RBP4) by using the baculovirus expression system and to detect its immunogenicity, the fusion DNA fragment of secretory signal peptide SS64 and human RBP4 gene was subcloned into a baculovirus transfer vector pFastBac-dual(pFBd), and the corresponding recombinant transfer plasmid was transformed into E. coli strain DH10bac, after transposition recombinant shuttle bacmid was screened out. The logarithmic phase Sf9 cells were transfected with the recombinant bacmid and then the recombinant baculovirus containing hRBP4 expression box were generated. After amplification of recombinant baculovirus, the recombinant baculovirus seeds were obtained. To express human RBP4, logarithmic phase Sf9 cells were infected with the virus seeds and SDS-PAGE and Western blotting were used to detect and identify the expression. Finally, to prepare a batch of RBP4 protein, logarithmic phase Sf9 cells in suspension culture were infected with recombinant baculovirus seeds and the supernatant was harvested after 120 hours post-infection for purification. Finally for preparation of polyclonal antibody and evaluation of immunogenicity, the recombinant hRBP4 from insect cells and from E. coli were immunized rabbits. Restriction enzyme digestion and sequencing confirmed that the recombinant baculovirus transfer plasmid was constructed correctly, and subsequently recombinant RBP4-bacmid was generated successfully. SDS-PAGE and Western blotting analysis suggested that human RBP4 protein was highly expressed in Sf9 cells with the molecular weight of approximately 23 kDa. The recombinant RBP4 protein could be secreted into the medium efficiently, and the expression level was calculated amount of 100 mg/L. Finally the rabbit antiserum was harvested after recombinant RBP4 immunization, therein the titer of antiserum against baculovirus recombinant RBP4 is 1:100 000 whereas the titer of antiserum against E. coli recombinant RBP4 is only 1:10 000. Overall, human RBP4 was high efficiently expressed successfully with good antigenicity in baculovirus system, and high affinity antiserum was obtained. A solid foundation was laid for the next step of the preparation of human serum RBP4 detection kit.

[Expression of human retinol-binding protein 4 in insect baculovirus system and preparation of its polyclonal antibody].

Gold-catalyzed hydroimination of terminal alkynes, giving rise to anti-Markovnikov adducts concomitant with unstable Markovnikov adducts is described. The elementary step can be applied for the construction of pyridine derivatives from ammonia and alkynes.

Anti-Markovnikov hydroimination of terminal alkynes in gold-catalyzed pyridine construction from ammonia.

Vaccination alone is not sufficiently effective to protect human from post-exposure rabies virus infection due to delayed generation of rabies virus neutralizing antibodies and weak cellular immunity. Therefore, it is vital to develop safer and more efficacious vaccine against rabies. PIKA, a stabilized chemical analog of double-stranded RNA that interacts with TLR3, was employed as adjuvant of rabies vaccine. The efficacy and safety of PIKA rabies vaccine were evaluated. The results showed that PIKA rabies vaccine enhanced both humoral and cellular immunity. After viral challenge, PIKA rabies vaccine protected 70-80% of animals, while the survival rate of non-adjuvant vaccine group (control) was 20-30%. According to the results of toxicity tests, PIKA and PIKA rabies vaccine are shown to be well tolerated in mice. Thus, this study indicates that PIKA rabies vaccine is an effective and safe vaccine which has the potential to develop next-generation rabies vaccine and encourage the start of clinical studies.

A novel rabies vaccine based-on toll-like receptor 3 (TLR3) agonist PIKA adjuvant exhibiting excellent safety and efficacy in animal studies.

A 1,4-addition of a dichlorogermylene dioxane complex with α,β-unsaturated imine 1 gave a dichlorogermane derivative 2 bearing a GeC₃N five-membered ring skeleton. By reducing 2 with KC₈, cyclic (alkyl)(amino)germylene 3 was synthesized and fully characterized. Germylene 3 readily reacted with TEMPO, N₂O and S₈, producing the 1:2 adduct 4, the oxo-bridged dimer 5 and the sulfido-bridged dimer 6, respectively.

Liliang Wang

Department of Mechanical Engineering

Imperial College London

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

Liliang Wang

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Mechanical Engineering

Imperial College London

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

Department of Mechanical Engineering