Search

The adsorption and subsequent dissociative reaction of methanol (CH 3 OH) on clean ZnO ( 10 1 ¯ 0 ) surface were investigated using the density functional theory methods and the periodic slab models. There are three adsorption modes of methanol were investigated. Among the two initially-stable adsorbed CH 3 OH structures, the pathways of methanol dissociation via bond scission of the O H, C H and C O bonds to form methoxide, hydroxymethyl and methyl radicals, respectively, were examined. Several possible pathways for CH 3 OH decomposition on the ZnO ( 10 1 ¯ 0 ) surface were proposed. Our calculated results pointed out that the most favorable reaction pathway is CH 3 OH (a) → CH 3 O (a) + H (a) → CH 2 O (a) + 2H (a) → CH 2 O (g) + 2H (a) . In addition, the nature of the surface–methanol bonding was investigated through scrutiny of electron density difference (EDD) contour plot.

This paper presents a power-strength-based selective forwarding (PSF) mechanism to efficiently flood route requests (RREQs) during route discovery in multihop cellular networks (MCNs). In PSF, each mobile station utilizes the received power strength, instead of the connectivity or overheard information, to determine whether it has to be a forwarding participant or not. It reduces the signaling overhead and prevents unnecessary interference during route discovery. An analytical method is proposed to set the power thresholds required to ensure a target connectivity probability. The accuracy of the proposed method was verified via computer simulation. Simulation results show that the proposed PSF mechanism can significantly reduce the number of RREQs while ensuring the connectivity probability.

This paper proposes a new model to evaluate the reliability, as a metric of the quality of fault tolerant systems that undergo repair and maintenance processes. The model is developed based on the markovian nature of repair and maintenance processes. The repair and maintenance processes are characterized with respect to mean time between failure, mean time between repair and mean time between maintenance. Simulation results are shown to demonstrate various co-effects of repair and maintenance processes on the reliability under the assumption of the proposed model.

Deletions involving the chromosome 9p21 region have been reported as frequent events in non-small cell lung cancer (NSCLC). To investigate potential tumor-suppressor gene (TSG) loci within the 9p21 region, which also harbors the candidate TSG locus CDKN2a, we studied 32 cases of primary NSCLC for loss of heterozygosity (LOH). Tumor and paired normal lung cells were microdissected from lung tissue imprints and all samples screened using PCR-LOH analysis with 15 9p markers. In addition, 3 NSCLC cell lines and their matched normal lung and tumor DNA were similarly analyzed. LOH at the marker D9S259, which is proximal to the CDKN2a locus, was found most frequently (52%), while LOH at D9S942, the marker closest (5 kb) to the CDKN2a gene, was seen in only 17%. Homozygous loss of markers close to CDKN2a was, however, detected in 2 of the 3 cell lines and one accompanying tumor sample. We propose that a TSG in the region of deletion proximal to the CDKN2a gene within 9p21 may play a significant role in the pathogenesis and progression of NSCLC.

We investigated preneoplastic lesions associated with lung cancer to determine at what stage in lung carcinogenesis K-ras mutations appear. We selected six archival lung cancer resection cases that had ras mutations. We precisely microdissected 74 relevant areas from paraffin-embedded sections. K-ras mutations at codons 12, 13, and 61 were determined by the designed restriction fragment length polymorphism method using mismatched nested primers and confirmed by direct sequencing. All samples of invasive and metastatic cancers had K-ras mutations, as did four of five lesions of noninvasive cancer. Mutations were detected in only 1 of 12 dysplastic lesions and were absent from hyperplastic and normal-appearing cells. In all cases, the specific point mutations and the mutational pattern in the tumors, metastases, and the corresponding noninvasive lesions were identical. These results indicate that K-ras mutations arise relatively late in the pathogenesis of lung cancer and may be associated with the appearance of the malignant phenotype.

9550 Background: Older children with hepatoblastoma (HB) as well as liver tumors with features of hepatocellular carcinoma (HCC) often have more aggressive features and are resistant to the convent...

We compared the rate of recovery of corneal sensation in two randomly selected groups of patients with rhegmatogenous retinal detachment whose eyes were otherwise healthy. One of the groups underwent removal of the epithelium and, and the other was characterized by nonremoval of the epithelium. The corneal sensations were measured serially with an esthesiometer. The return of corneal sensation occurred sooner in the nonremoval group than in the removal group in the early postoperative period, but at three months, the difference was negligible.

A patient with X-linked juvenile retinoschisis was followed from age 5 years. At age 15 he developed rubeosis iridis and neovascular glaucoma in one eye, resulting in no light perception. A review of the literature revealed this case to be the first reported association of X-linked juvenile retinoschisis and neovascular glaucoma.