Effects of Mesocyclops longisetus (Copepoda:Cyclopidae) on mosquitoes that inhabit tires: influence of litter type, quality, and quantity

A 59-week study was conducted to evaluate the impact of adult Mesocyclops longisetus populations on larval mosquito species inhabiting tires. Greater than 90% reduction of number of 1st and 2nd instars was recorded by 4 wk with 90% reduction of number of 3rd and 4th instars after 7 wk. Reduced control was noted with the onset of cooler winter water temperature. Overall. a 52% reduction in the number of 1st and 2nd instars was achieved, and a 57% reduction was noted in number of 3rd- and 4th-instar mosquito larvae. Cooler temperatures resulted in a decline of adult Mesocyclops, which resulted in reduced larval control. Significantly greater numbers of Mesocyclops adults were collected in tires with either new litter or heavy amounts of litter regardless of litter type. Lastly, litter type, either oak leaves or pine needles, did not influence mosquito reduction or abundance of Mesocyclops populations.     

Performance of PRMA in a mobile radio channel

The performance of the packet reservation multiple access (PRMA) protocol in a real mobile radio channel that suffers from propagation impairments including multipath fading, shadowing and distant-dependent path loss, is studied by simulation. Significant performance degradations, measured by the number of simultaneous conversations supportable in a cell subject to a packet dropping probability of 1%, are observed. Additionally, receiver capture is also found to be ineffective in increasing this supportable number of simultaneous conversations. A modified PRMA protocol is then introduced, and shown to be capable of improving performance through minimizing premature loss of reservations and avoiding additional collisions that arise due to the channel errors.     

Sequence-selective biosensor for DNA based on electroactive hybridization indicators

Deoxyribonucleic acid was covalently immobilized onto oxidized glassy carbon electrode surfaces that had been activated using 1-[3-(dimethylamino)-propyl]-3-ethylcarbodimide hydrochloride and N-hydroxysulfosuccinimide. This reaction is selective for immobilization through deoxyguanosine (dG) residues. Immobilized DNA was detected voltammetrically, using tris (2,2'-bipyridyl)cobalt(III) perchlorate and tris (1,10-phenanthroline)cobalt(III) perchlorate (Co(bpy)3(3+) and Co(phen)3(3+). These complexes are reversibly electroactive (1e-) and preconcentrate at the electrode surface through association with double-stranded DNA. Voltammetric peak currents obtained with a poly(dG)poly(dC)-modified electrode depend on [Co(bpy)3(3+)] and [Co(phen)3(3+)] in a nonlinear fashion and indicate saturation binding with immobilized DNA. Voltammetric peak currents for Co(phen)3(3+) reduction were used to estimate the (constant) local DNA concentration at the modified electrode surface; a binding site size of 5 base pairs and an association constant of 1.74 x 10(3) M(-1) yield 8.6 +/- 0.2 mM base pairs. Cyclic voltammetric peak separations indicate that heterogeneous electron transfer is slower at DNA-modified electrodes than at unmodified glassy carbon electrodes. A prototype sequence-selective DNA sensor was constructed by immobilizing a 20-mer oligo (deoxythymidylic acid) (oligo(dT)20), following its enzymatic elongation with dG residues, which yielded the species oligo(dT)20(dG)98. Cyclic voltammograms of 0.12 mM Co(bpy)3(3+) obtained before and after hybridization with poly-(dA) and oligo(dA)20 show increased cathodic peaks after hybridization. The single-stranded form is regenerated on the electrode surface by rinsing with hot deionized water. These results demonstrate the use of electroactive hybridization indicators in a reusable sequence-selective biosensor for DNA.     

Synthesis of 2'(3')-O-DL-alanyl hexainosinic acid using T4 RNA ligase: suppression of the enzymic reverse transfer reaction by alkaline phosphatase

2'(3')-O-DL-Alanyl (Ip)5I was synthesized by a new method. An alanine ortho ester of inosine 5'-phosphate was added to (Ip)4I using the ATP-independent reaction of T4 RNA ligase, and the product was converted smoothly to the desired ester. The enzymic reverse transfer reaction was conveniently suppressed by the dephosphorylation of the adenosine 5'-phosphate coproduct, catalyzed in situ by alkaline phosphatase.     

Frequency of the codon 807 mutation in the cGMP phosphodiesterase beta-subunit gene in Irish setters and other dog breeds with hereditary retinal degeneration

Prostate cancer (PCA), the most commonly diagnosed cancer in males in the United States, is the second leading cause of cancer-related deaths of males in this country. Because of the poor success rate in the treatment of PCA, an intervention at an early stage may reduce the progression of small carcinoma to large metastatic lesion, thereby reducing PCA-related deaths. Concerted efforts are needed to establish mechanism-based approaches to develop: (a) the markers for early detection of the disease as well as toward monitoring the efficacy of treatment(s); and (b) novel chemopreventive strategies against PCA. Using unique samples of pair-matched benign and cancer tissue obtained from the same PCA patient, we showed that ornithine decarboxylase (ODC) activity is significantly (P < 0.001) elevated in PCA (1142 +/- 100; mean +/- SE) than in paired benign tissue (427 +/- 51; mean +/- SE). The immunoblot analysis also showed a significant elevation in the protein expression of ODC in the PCA tissues as compared with the paired benign tissue. Furthermore, our data showed that the ODC activity in the prostatic fluid obtained by a digital rectal massage from the patients with PCA (3847 +/- 162; mean +/- SE) was significantly higher than in the patients with benign prostatic hyperplasia (2742 +/- 167; mean +/- SE) or normal individuals (1244 +/- 67; mean +/- SE). This observation might be of significance because the prostatic fluid could be obtained noninvasively by digital rectal massage. We suggest that ODC could serve as a target for early detection of human PCA as well as for monitoring the efficacy of treatment(s). The development of ODC as a target for novel chemopreventive strategies against PCA is an intriguing possibility.     

Water‐soluble chromophore containing copolymers for bottom antireflection coating applications in lithography

Regulatory concerns in the semiconductor industry from both VOC emissions and solvent handling have prompted the desire to introduce water‐based formulations in spin‐coating fabrication processes. As resolution demands for i‐line lithography are driven to finer feature size and architecture, the need for antireflection coatings as a means of eliminating feature distortions from back reflected light is increasing. Common image irregularities, such as reflective notching and standing wave effects, can be effectively eliminated through application of an antireflection coating of optimal thickness between the resist layer and substrate. This work describes the design and development of novel side‐chain methacrylate copolymers for use in water‐based antireflection coating formulations. A pendant chromophore is incorporated into the polymer structure to allow optimization of the critical coating optical properties, refractive index, and absorption coefficient. The polymer solubility parameter and crosslinking density can be tailored by incorporation of appropriate functionality to allow compatibility with the device fabrication process. Terpolymers were designed, which were water‐soluble, had a thermally activated crosslinking mechanism, and contained a keto‐ester azobenzene chromophore that was highly absorbing at i‐line wavelength. Optical properties of polymer films were collected by spectroscopic elipsometry and utilized in the design process to identify the optimum chromophore structure. Lithographic images, fabricated utilizing these coatings, were of excellent quality, allowing critical dimension resolutions of less than 0.3 µm. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1304–1316, 1999