4,041 research outputs found
UK-China Creative Industries: Insights from AHRC SEED Fellowship
No full textThis book is the outcome of the UK-China Creative Industries Research and Innovation Hub Fellowship, funded by United Kingdom Research and Innovation (UKRI)/Arts and Humanities Research Council (AHRC).UK-China creative industries research and innovation hub fellowship: the SEED Fellowship is funded by UKRI/ Arts and Humanities Research Council. ( AH/Y000722/1)
Intermolecular C-H activation effected by CP*W(NO)-containing complexes
No full textThermolysis of Cp*W(NO)(CH₂CMe₃)₂ (2.1) in halo, methoxy, or phenylethynyl-substituted benzenes leads to the formation of the alkylidene intermediateCp*W(NO)(=CHCMe₃) which selectively activates ortho C-H bonds of the organicsubstrates. The ortho-regioselectivity diminishes as the size of the substituent increasesfrom F (97 %) to C-=CPh (51 %). In the solid-state structure of all complexes the ortho-substituent is not coordinated to the metal centre; rather, the metal centre is engaged inagostic interactions with a neopentyl methylene C-H bond. Mechanistic studies on the chlorobenzene reaction reveal that the ortho-C-H-activation product is preferentially formed via thermal isomerization from the meta / para-C-H-activation isomers.
Reactions between Cp*W(NO)(CH₂EMe₃)Cl (E = C or Si) and a variety of bis(allyl)magnesium reagents lead to the expected formation of Cp*W(NO)(alkyl)(allyl)complexes. Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCH₂) (3.5), Cp*W(N0)(CH₂CMe₃)(η³-CH₂CMeCH₂) (3.6), Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHMe) (3.7),Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHPh) (3.8) and Cp*W(N0)(CH₂SiMe₃)(η³-CH₂CHCHMe) (3.9) have thus been synthesized in moderate yields. The solid-state molecular structures of 3.5 and 3.7-3.9 feature a σ-π distorted ally! ligand in the endoconformation. Complex 3.5 reacts with pyrrolidine at RT to form Cp*W(NO)(NC₄H8)(CHMeCH₂NC₄H8) (3.10), a nucleophilic-attack product. Complexes 3.6-3.9 effect the concurrent N-H and α-C-H activation of pyrrolidine at RT and form
alkyl-amido complexes analogous to the previously known Cp*W(N0)(CH₂EMe)(NC₄H₇-2-CMe₂CH=CH₂) (3.12).
Thermolysis of Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHMe) (3.7) at RT leads to the loss of neopentane and the formation of the η²-diene intermediate Cp*W(N0)(η²-CH₂=CHCH=CH₂) (A) which has been isolated as a PMe₃ adduct. In the presence of saturated organic substrates, C-H activation occurs exclusively at the methyl positions of the molecule. Reactions between intermediate A and unsaturated substrates lead to coupling between the coordinated η²-diene and the unsaturation on the organic molecule.Treatment of Cp*W(N0)(n-C₅H₁₁)(η³-CH₂CHCHMe) (4.1) with I₂ at -60 °C produces n-C₅H₁₁ I in moderate yields.
Thermolysis of Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHPh) (3.8) in benzene at 75 °C for one day leads to the exclusive formation of Cp*W(N0)(H)(η³-PhCHCHCHPh) (5.1).Trapping, labelling, and monitoring experiments suggest that 5.1 is formed via 1) the loss of neopentane and the generation of the allene intermediate Cp*W(N0)(η²-CH₂=C=CHPh), 2) the C-H activation of benzene resulting in a phenyl phenylallyl complex, and 3) the thermal isomerization of this latter species to 5.1.Science, Faculty ofChemistry, Department ofGraduat
Title: Understanding HIV reverse transcription: the structure and function of the N-terminal domain in human Lysyl-tRNA Synthetase Author: Tran, U., Nguyen, H., Refaei, M., Calhoun, J., and Tsang, P. College of Arts & Sciences, University of Cincinnati
No full textBy Uyen Tran, Biochemistry
Advisor: Pearl Tsang
Presentation ID: PM_D19
Abstract: The enzyme Lysyl-tRNA Synthetase in human, abbreviated hKRS, is packaged into new HIV-1 virus particles. The eukaryotic enzyme consists of three domains: an anticodon binding domain, a catalytic domain, and an N-terminal domain that is unique to higher eukaryotic organisms. Previous studies have shown that the presence of the N-terminal domain (NTD) greatly increases the selective incorporation of tRNA-Lys3 of HIV-1; however, the NTD structure and the means by which it interacts with the tRNA are still not well characterized or understood. The research conducted and described here involves purification of hKRS NTD and our studies of its structural properties. This specifically involved the growth and purification of the recombinant form of the NTD in Escherichia coli BL21 DE3 cells. Purified NTD protein that was obtained was then concentrated and the protein concentration was determined using UV spectrophotometry and other techniques. The purified, concentrated NTD was then studied using Circular Dichroism to examine the secondary structure of this protein as a function of concentration and temperature
Acute pancreatitis combined with acute Budd-Chiari syndrome as the initial manifestation of small cell lung cancer
No full text
Synergistic anti-tumor effect of combonation radio- and immunotherapy by electro-gene therapy plus intra-tumor injection of dendritic cells.
No full textValue-Assigned Pulse Shape Discrimination for Neutron Detectors
No full textUsing the waveforms from a digital electronic system, an offline analysis technique on pulse shape discrimination (PSD) has been developed to improve the neutron-gamma separation in a bar-shaped NE-213 scintillator that couples to a photomultiplier tube (PMT) at each end. The new improved method, called the 'valued-assigned PSD' (VPSD), assigns a normalized fitting residual to every waveform as the PSD value. This procedure then facilitates the incorporation of longitudinal position dependence of the scintillator, which further enhances the PSD capability of the detector system. In this article, we use radiation emitted from an AmBe neutron source to demonstrate that the resulting neutron-gamma identification has been much improved when compared to the traditional technique that uses the geometric mean (GM) of light outputs from both PMTs. The new method has also been modified and applied to a recent experiment at the National Superconducting Cyclotron Laboratory (NSCL) that uses an analog electronic system
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