The effects of a trace addition of silver upon elevated temperature ageing of an Al–Zn–Mg alloy

Microalloying additions of Ag (0.1 at.%) increase the hardening response of Al–Zn–Mg alloys to elevated temperature ageing in the range 100–200°C due to the formation of a high density of very fine η′ precipitate plates. The present study employed transmission electron microscopy (TEM) and three-dimension atom probe (3DAP) to study the early stages of ageing in the alloy Al–1.8Zn–3.4Mg–0.1Ag (at.%) in an attempt to identify the role of Ag in stimulating precipitation hardening. During isothermal ageing at 90°C, the hardening response is attributed to a high density of Zn–Mg–Ag rich solute clusters and GP zones. During ageing at 150°C, η′ precipitates nucleate at Zn–Mg–Ag rich solute clusters, the former growing as {111} platelets with an average composition of approximately 20 at.% Zn, 20 at.% Mg and 1.4 at.% Ag. The 3DAP data indicates that the co-segregation of Zn and Ag and subsequently Zn and Mg atoms precedes the formation of the Zn–Mg–Ag rich solute clusters. The GP zones and η′ precipitates were observed to possess a Zn:Mg ratio close to 1:1, whereas the equilibrium η precipitates possessed compositions consistent with MgZn₂. Furthermore, partitioning of Ag was observed inside all precipitate phases, viz. G.P. zones, η′ and η.     

Sum Rules for the Quasi-Static and Visco-Elastic Response of Disordered Solids at Zero Temperature

We study exact results concerning the non-affine displacement fields observed by Tanguy et al. [Europhys. Lett. 57, 423 (2002), Phys. Rev. B 66, 174205 (2002)] and their contributions to elasticity. A normal mode analysis permits us to estimate the dominant contributions to the non-affine corrections to elasticity and relate these corrections to the correlator of a fluctuating force field. We extend this analysis to the visco-elastic dynamical response of the system.     

-Halogenoketones—XIV Studies in the chemistry of 2'-hydroxyacrylophenones

An initial study of the side-chain unsubstituted 2'-hydroxyacrylophenone system shows it to have a considerably greater propensity for intermolecular addition than the comparable 2'-hydroxychalcone system, readily undergoing base-catalysed addition of, for example, alcohol and thereby diverting typical chalcone reactions requiring alcoholic alkali. 2'-Acetoxyacrylophenone dibromides and bromoalkoxides cyclize with base to chromone epoxides as do 2'-acetoxy--bromoacrylophenones in alcoholic alkali.     

Selective and cell-active inhibitors of the USP1/ UAF1 deubiquitinase complex reverse cisplatin resistance in non-small cell lung cancer cells

Ubiquitin-specific proteases (USPs) have in recent years emerged as a promising therapeutic target class. We identified selective small-molecule inhibitors against a deubiquitinase complex, the human USP1/UAF1, through quantitative high throughput screening (qHTS) of a collection of bioactive molecules. The top inhibitors, pimozide and GW7647, inhibited USP1/UAF1 noncompetitively with a K(i) of 0.5 and 0.7?μM, respectively, and displayed selectivity against a number of deubiquitinases, deSUMOylase, and cysteine proteases. The USP1/UAF1 inhibitors act synergistically with cisplatin in inhibiting cisplatin-resistant non-small cell lung cancer (NSCLC) cell proliferation. USP1/UAF1 represents a promising target for drug intervention because of its involvement in translesion synthesis and Fanconi anemia pathway?important for normal DNA damage response. Our results support USP1/UAF1 as a potential therapeutic target and provide an example of targeting the USP/WD40 repeat protein complex for inhibitor discovery.     

A practical, one-pot synthesis of sulfonylated pyridines

A concise and efficient one-pot synthesis of functionalized sulfonylated pyridines via an S(N)Ar reaction of readily available pyridines and sodium sulfinate salts in the presence of tetrabutylammonium chloride is presented.     

A rapid,chromatography-free route to substituted acridine–isoalloxazine conjugates under microwave irradiation

Microwave irradiation was applied to a sequence of condensation reactions from readily available 9-chloroacridines to provide a range of novel acridine–isoalloxazine conjugates. The combination of these two moieties, both of biological interest, was achieved by a chromatography-free route.     

Effects of pore structure and molecular size on diffusion in chromatographic adsorbents

Two computational approaches, namely Brownian dynamics and network modeling, are presented for predicting effective diffusion coefficients of probes of different sizes in three chromatographic adsorbents, the structural properties of which were determined previously using electron tomography. Three-dimensional reconstructions of the adsorbents provide detailed, explicit characteristics of the pore network, so that no assumptions have to be made regarding pore properties such as connectivity, pore radius and pore length. The diffusivity predictions obtained from the two modeling approaches were compared to experimental diffusivities measured for dextran and protein probes. Both computational methods captured the same qualitative results, while their predictive capabilities varied among adsorbents.