Synthesis of tricyclic benzimidazole-iminosugars as potential glycosidase inhibitors via a Mitsunobu reaction.

A series of tricyclic benzimidazole-iminosugars 1(a-f) and 2(a-f) were synthesized and evaluated for their their inhibitory activities against five glycosidases. The synthesis initiated from the benzyl protected sugar (aldehyde) 5 that reacted with 1,2-diaminobenzene to afford aldo-benzimidazole 6 by the iodine-induced oxidative condensation. Then, tricyclic compound 7 was obtained in high yields of 73%-87% by the key Mitsunobu reaction through intramolecular cyclization of the unprotected OH and the NH in 6.

Synthesis of tricyclic quinazolinone-iminosugars as potential glycosidase inhibitors via a Mitsunobu reaction.

A series of novel tricyclic quinazolinone-iminosugars 1 (a-c) were synthesized from the benzyl protected sugars through three steps. Firstly, the benzyl protected sugar (aldehyde) 5 reacted with o-aminobenzamide by the iodine-induced oxidative condensation to afford the corresponding aldo-quizanolinone 6. Secondly, through the intramolecular cyclization of the unprotected OH and the amide NH in 6, the tricyclic compounds 7 and 8 were constructed by the key Mitsunobu reaction.

Synthesis of tetracyclic azasugars fused benzo[e][1,3]thiazin-4-one by the tandem Staudinger/aza-Wittig/cyclization and their HIV-RT inhibitory activity.

Azasugar aldehydes 6a and 6b containing azido groups were prepared from D-mannose. Three novel tetracyclic azasugars fused benzo[e][1,3]thiazin-4-one 9a-1, 9a-2 and 9a-3 were conveniently synthesized from 6a by the tandem intramolecular Staudinger/aza-Wittig/cyclization reaction under microwave radiation. Two unexpected elimination compounds 8b-1 and 8b-2 were achieved as the main products from 6b in the same processes.

Modeling and Experimental Demonstration of a Hopfield Network Analog-to-Digital Converter with Hybrid CMOS/Memristor Circuits.

The purpose of this work was to demonstrate the feasibility of building recurrent artificial neural networks with hybrid complementary metal oxide semiconductor (CMOS)/memristor circuits. To do so, we modeled a Hopfield network implementing an analog-to-digital converter (ADC) with up to 8 bits of precision. Major shortcomings affecting the ADC's precision, such as the non-ideal behavior of CMOS circuitry and the specific limitations of memristors, were investigated and an effective solution was proposed, capitalizing on the in-field programmability of memristors.

Fully parallel write/read in resistive synaptic array for accelerating on-chip learning.

A neuro-inspired computing paradigm beyond the von Neumann architecture is emerging and it generally takes advantage of massive parallelism and is aimed at complex tasks that involve intelligence and learning. The cross-point array architecture with synaptic devices has been proposed for on-chip implementation of the weighted sum and weight update in the learning algorithms. In this work, forming-free, silicon-process-compatible Ta/TaOx/TiO2/Ti synaptic devices are fabricated, in which >200 levels of conductance states could be continuously tuned by identical programming pulses.

High precision tuning of state for memristive devices by adaptable variation-tolerant algorithm.

Using memristive properties common for titanium dioxide thin film devices, we designed a simple write algorithm to tune device conductance at a specific bias point to 1% relative accuracy (which is roughly equivalent to seven-bit precision) within its dynamic range even in the presence of large variations in switching behavior. The high precision state is nonvolatile and the results are likely to be sustained for nanoscale memristive devices because of the inherent filamentary nature of the resistive switching. The proposed functionality of memristive devices is especially attractive for analog computing with low precision data.

Characterization of Titania Incorporated with Alumina Nanocrystals and Their Impacts on Electrical Hysteresis and Photoluminescence.

The structural and optical characterizations of titania incorporated with alumina nanocrystals have been presented in this paper and the films exhibit excellent properties like low current density, small hysteresis as well as high photoluminescence quantum yields of about 361 nm. These properties are promising for the applications in future electronic devices.