Alzheimer's disease (AD) is a chronic neurodegenerative disease, which is considered as one of the most intractable medical problems with heavy social and economic costs. The current drugs for AD, including acetylcholinesterase inhibitors (AChEIs) and memantine, a NMDA receptor antagonist, only temporarily ameliorate cognitive decline, but are unable to stop or reverse the progression of dementia. This paper reviewed the recent advance in AD drug development. The drug discovery programs under clinical trials targeting cholinergic system, α7 nicotinic acetylcholine receptors (nAChRs), N-methyl-d-aspartate receptor (NMDAR), β-secretase, γ-secretase modulators, tau, inflammatory mediators and glucagon-like peptide-1 (GLP-1) were discussed. Though several drug discovery programs are ongoing, the high failure rate is an outstanding issue. Novel techniques and strategies are desperately needed to significantly accelerate this process.

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Three alloys, containing niobium, vanadium and titanium, respectively, were refined and the strengthening effect attained after adding them individually in a 20MnSi low-alloy rebar steel was investigated. The results show that the strengthening effect attained due to the addition of niobium is the best, whereas that due to the addition of titanium is the poorest. Grain refinement and precipitation strengthening are the main strengthening mechanisms observed in niobium-steel and vanadium-steel, whereas only precipitation strengthening is observed in titanium-steel. Moreover, the average grain size of niobium-steel is the smallest among the four types of steels, while the size of ferrite and pearlite microstructures show almost no obvious change as compared to the base steel in the case of titanium-steel. Furthermore, the volume fractions of ferrite and pearlite in the four tested steels have no noticeable change.

Niobium (Nb), a microalloy element, is purposefully added to improve the thermal stability of ferrite grains in a low-carbon ultrafine grain (UFG) steel. Results manifest the excellent thermal stability in the Nb-UFG steel with 0.028 wt% Nb addition by providing favorable kinetics and thermodynamic stabilization effects. The almost unchanged grain size and mechanical properties of Nb-UFG steels annealed for 45 and 180 min at 500 C are simultaneously obtained by the heterogeneous ferrite grains, NbC precipitates, and geometrically necessary dislocations (GNDs) mainly formed during tensile tests. The imperceptible change in size and volume fraction of NbC particles of the two Nb-UFG steels annealed at different time are attributed to the inherent thermal stability of NbC and main precipitation pattern of NbC particles from the α phase.