Analysis and performance comparison of adaptive differential pulse code modulation data compression systems

Electrical EngineeringAdvances in audio data compression are largely driven by the need to conserve transmission rate or bandwidth, while maintaining the ability to accurately reconstruct the signal at the receiver. This report examines data compression methods with an emphasis on techniques for the compression of audio data. An overview of data compression schemes is presented to provide the background for a performance comparison between selected versions of data compression systems featuring adaptive differential pulse code modulation (ADPCM) schemes. Two different types of data compression systems are investigated; IIR and FIR impulse implementations. A modification to the basic ADPCM system using a modular function is implemented. The modular operation results in a smaller size codebook and prevents data expansion when the source is not matched to the code. This modification is utilized for both types of ADPCM coders compared. To complete the compression system Huffman coding, is employed to encode and decode the compressed data to and from binary form.http://archive.org/details/analysisndperfor1094532143NAU.S. Navy (U.S.N.) author.Approved for public release; distribution is unlimited

Synthesis and antiproliferative activity of coumarin-estrogen conjugates against breast cancer cell lines

The syntheses and cytotoxic activity of coumarin-estrogen conjugates are described. In vitro results indicated that conjugates 10, 11 and 13 show growth inhibitory activities at 5-dose concentration (100, 10, 1, 0.1, 0.01 μM) against the following NCI-7- human breast cancer cell lines: BT-549, HS 578T, MCF 7, MDA-MB-231/ATCC, MDA-MB-435, NCI/ADR-RES, and thus serve as new leads for further development of antibreast cancer agent

A Review of Coumarin Derivatives in Pharmacotherapy of Breast Cancer

The coumarin (benzopyran-2-one, or chromen-2-one) ring system, present in natural products (such as the anticoagulant warfarin) that display interesting pharmacological properties, has intrigued chemists and medicinal chemists for decades to explore the natural coumarins or synthetic analogs for their applicability as drugs. Many molecules based on the coumarin ring system have been synthesized utilizing innovative synthetic techniques. The diversity oriented synthetic routes have led to interesting derivatives including the furanocoumarins, pyranocoumarins, and coumarin sulfamates (COUMATES), which have been found to be useful in photochemotherapy, antitumor and anti-HIV therapy, and as stimulants for central nervous system, antibacterials, anti-inflammatory, anti-coagulants, and dyes. Of particular interest in breast cancer chemotherapy, some coumarins and their active metabolite 7-hydroxycoumarin analogs have shown sulfatase and aromatase inhibitory activities. Coumarin based selective estrogen receptor modulators (SERMs) and coumarin-estrogen conjugates have also been described as potential antibreast cancer agents. Since breast cancer is the second leading cause of death in American women behind lung cancer, there is a strong impetus to identify potential new drug treatments for breast cancer. Therefore, the objective of this review is to focus on important coumarin analogs with antibreast cancer activities, highlight their mechanisms of action and structure-activity relationships on selected receptors in breast tissues, and the different methods that have been applied in the construction of these pharmacologically important coumarin analogs

1H-NMR and 13C-NMR Spectral Assignments of Spiramycins I and III

The spiramycins (1a-1c) are 16-membered macrolide antibiotics produced by the bacteria Streptomyces ambofaciens (1) (Scheme I). This series of compounds shows gram-positive antibacterial activity as well as antimicrobial activity against both Toxoplasma gondii and Cryptosporidium, two protozoans which can result in potentially fatal opportunistic infections associated with AIDS (2,3). Our interest in the spiramycins has been the production of spiramycin derivatives through chemical and biochemical modifications of the basic spiramycin chemical structure. To prove unambiguously the structure of any derivatives, a complete structural understanding of the spiramycins themselves was necessary. After a thorough search of the literature, we found various NMR structural characterizations of these compounds. Unfortunately, many of the structural aspects of the spiramycins are reported incorrectly or not at all. We have made the complete NMR spectral assignments of spiramycins I and III based on our interpretation of the NMR techniques of DEPTGL, HETCOR, HMBC, and COSY

Synthesis and Antimicrobial Activity of N,N′-Bis(2-hydroxylbenzyl)-1,2-ethanediamine Derivatives

A series of N,N′-Bis(2-hydroxylbenzyl)-1,2-ethanediamine derivatives and its schiff bases were synthesized, characterized and screened for in vitro antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. Result indicated that the ethylenediamine derivatives, N,N′-Bis(2-hydroxy-5-bromobenzyl)-1,2-ethanediamine (21), and N,N′-Bis(2-hydroxy-5-chlorobenzyl)-1,2-ethanediamine (22) showed the most favorable antimicrobial activity exhibiting LC50 of 11.6 and 8.79 μM against S.enterica, 86 and 138 μM against P. aeruginosa, and 140 and 287 μM against S. aureus, respectively. These compounds displayed highest level of resistance with S. aureus. Thus, the high level of activity seen with the compounds (21, 22) suggests that these compounds could serve as the leads for development of novel synthetic compounds with enhanced antimicrobial activity