Simple Floating Voltage-Controlled Memductor Emulator for Analog Applications

The topic of memristive circuits is a novel topic in circuit theory that has become of great importance due to its unique behavior which is useful in different applications. But since there is a lack of memristor samples, a memristor emulator is used instead of a solid state memristor. In this paper, a new simple floating voltage-controlled memductor emulator is introduced which is implemented using commercial off the shelf (COTS) realization. The mathematical modeling of the proposed circuit is derived to match the theoretical model. The proposed circuit is tested experimentally using different excitation signals such as sinusoidal, square, and triangular waves showing an excellent matching with previously reported simulations

Power Dissipation of Memristor-Based Relaxation Oscillators

Recently, many reactance-less memristive relaxation oscillators were introduced, where the charging and discharging processes depend on memristors. In this paper, we investigate the power dissipation in different memristor based relaxation oscillators. General expressions for these memristive circuits as well as the power dissipation formulas for three different topologies are derived analytically. In addition, general expressions for the maximum and minimum power dissipation are calculated. Finally, the calculated expressions are verified using PSPICE simulations showing very good matching

Routine use of antimicrobial drugs during the 2004 cholera epidemic in Douala, Cameroon

Objectives: To evaluate routine use of antimicrobial drugs for treatment and prevention of cholera with special regards to the evolution of the antimicrobial drug resistance patterns of V. cholerae strains. Design: Retrospective population-based descriptive study. Subjects: Four thousand nine hundred and forty one notified cholera cases, their 15,381 patients' guards and their 159,263 household members and close neighbours. Results: A total of 4,941 patients received antibiotic therapy according to the treatment protocols. Prophylactic treatment was administered to 15,381 patients' guards in hospitals and to 159,263 household members and close neighbours during home visits. Over the entire outbreak, the antimicrobial susceptibility patterns of V. cholerae strains isolated remained stable. Conclusions: The routine use of antimicrobial therapy for cholera cases associated with simultaneous and large scale chemoprophylaxis of close contacts does not seem in our experience to compromise the stability of V. cholerae susceptibility profiles to drugs when applied within a comprehensive package of rigorously monitored community interventions. The role of therapy and chemoprophylaxis in limiting the extent of a cholera epidemic is however difficult to ascertain from our experience. Field trials need to be designed to elucidate this aspect. The East African Medical Journal Vol. 83 (11) 2006: pp. 596-60

Induction of antibacterial metabolites by co-cultivation of two Red-Sea-sponge-associated actinomycetes <i>Micromonospora</i> sp. UR56 and <i>Actinokinespora</i> sp. EG49

Liquid chromatography coupled with high resolution mass spectrometry (LC-HRESMS)-assisted metabolomic profiling of two sponge-associated actinomycetes, Micromonospora sp. UR56 and Actinokineospora sp. EG49, revealed that the co-culture of these two actinomycetes induced the accumulation of metabolites that were not traced in their axenic cultures. Dereplication suggested that phenazine-derived compounds were the main induced metabolites. Hence, following large-scale co-fermentation, the major induced metabolites were isolated and structurally characterized as the already known dimethyl phenazine-1,6-dicarboxylate (1), phenazine-1,6-dicarboxylic acid mono methyl ester (phencomycin; 2), phenazine-1-carboxylic acid (tubermycin; 3), N-(2-hydroxyphenyl)-acetamide (9), and p-anisamide (10). Subsequently, the antibacterial, antibiofilm, and cytotoxic properties of these metabolites (1&ndash;3, 9, and 10) were determined in vitro. All the tested compounds except 9 showed high to moderate antibacterial and antibiofilm activities, whereas their cytotoxic effects were modest. Testing against Staphylococcus DNA gyrase-B and pyruvate kinase as possible molecular targets together with binding mode studies showed that compounds 1&ndash;3 could exert their bacterial inhibitory activities through the inhibition of both enzymes. Moreover, their structural differences, particularly the substitution at C-1 and C-6, played a crucial role in the determination of their inhibitory spectra and potency. In conclusion, the present study highlighted that microbial co-cultivation is an efficient tool for the discovery of new antimicrobial candidates and indicated phenazines as potential lead compounds for further development as antibiotic scaffold

The genus <i>Micromonospora</i> as a model microorganism for bioactive natural product discovery

This review covers the development of the genus Micromonospora as a model for natural product research and the timeline of discovery progress from the classical bioassay-guided approaches through the application of genome mining and genetic engineering techniques that target specific products. It focuses on the reported chemical structures along with their biological activities and the synthetic and biosynthetic studies they have inspired. This survey summarizes the extraordinary biosynthetic diversity that can emerge from a widely distributed actinomycete genus and supports future efforts to explore under-explored species in the search for novel natural products

Hardware acceleration of DNA pattern matching using analog resistive CAMs

DNA pattern matching is essential for many widely used bioinformatics applications. Disease diagnosis is one of these applications since analyzing changes in DNA sequences can increase our understanding of possible genetic diseases. The remarkable growth in the size of DNA datasets has resulted in challenges in discovering DNA patterns efficiently in terms of run time and power consumption. In this paper, we propose an efficient pipelined hardware accelerator that determines the chance of the occurrence of repeat-expansion diseases using DNA pattern matching. The proposed design parallelizes the DNA pattern matching task using associative memory realized with analog content-addressable memory and implements an algorithm that returns the maximum number of consecutive occurrences of a specific pattern within a DNA sequence. We fully implement all the required hardware circuits with PTM 45-nm technology, and we evaluate the proposed architecture on a practical human DNA dataset. The results show that our design is energy-efficient and accelerates the DNA pattern matching task by more than 100× compared to the approaches described in the literature