A characteristics-based finite element method for transmission line problem

This paper presents a numerical model of transmission line equations based on a combination of the finite element method and the generalized method of characteristics. A local system of the transmission line finite element is obtained using the generalized method of characteristics applied to the Telegrapher's equations. In this way, a spatial functional approximation using local shape functions together with the generalized trapezoidal rule used for time integration as it is done in the classical finite element formulation is avoided and higher accuracy of results is obtained. In order to show the essential principles of the proposed numerical method, for sake of simplicity, the scope of the paper is restricted to a single transmission line problem at the low frequency regime.     

Optical, electrical and structural properties of Cu2Te thin films deposited by magnetron sputtering

Thin films of Cu₂Te were deposited, at room temperature, on glass substrates by magnetron sputtering from independent Cu and Te sources. This work presents the effect of annealing temperature on the optical, structural, and electrical properties of sputtered Cu₂Te films. Annealing above 300 °C resulted in stoichiometric and near stoichiometric Cu₂Te phases, whereas temperatures above 400 °C yielded films with single Cu₂Te phase. In contrast, annealing at temperatures of 250 °C and below resulted in mixed phases of CuTe, Cu₇Te₅, Cu_1.8Te, and Cu₂Te. Analyses of transmittance and reflectance measurements for Cu₂Te indicate that photon absorption occurs via indirect band transitions for incident photons with energy above the band gap energy and free carrier absorption below the band gap energy. The determined indirect band gap was 0.90 eV and its associated phonon energy was 0.065 eV. Optical phonon scattering was identified as the mechanism through which the momentum is conserved during absorption by free carriers. Electrical measurements show p-type conductivity and highly degenerate semiconducting behavior with a hole carrier concentration p = 5.18 × 10²¹ cm^− 3.     

Peripheral Blood miR-328 Expression as a Potential Biomarker for the Early Diagnosis of NSCLC

Lung cancer is often diagnosed at an advanced stage, with subsequently poor prognosis. There are no biomarkers available to facilitate early diagnosis or to discriminate between benign and malignant nodules. MicroRNAs (miRNAs) are stable molecules that can be found and measured in peripheral blood, thus representing potential diagnostic biomarkers. We evaluated 100 individuals comprising 86 patients with predominantly early-stage non-small cell lung cancer (NSCLC) and 24 healthy donors. RNA was extracted from peripheral blood samples and the expression of a panel of miRNAs was analyzed by Real-Time PCR method. Expression levels of miR-328, miR-18a, miR-339 and miR-140 were significantly higher in NSCLC patients than in healthy donors (p < 0.05). In particular, miR-328 showed good diagnostic accuracy in discriminating between patients with early NSCLC and healthy donors (AUC ROC 0.82, 95% CI 0.72–0.92), with 70% sensitivity and 83% specificity at the best relative expression cut-off of 300. Moreover, miR-339 was a good discriminant between healthy donors and late-stage NSCLC patients (AUC ROC 0.79, 95% CI 0.68–0.91). In conclusion, miR-328 represents a potential diagnostic biomarker of NSCLC, especially for the identification of early-stage tumors. Its role in discriminating between benign and malignant nodules detected by spiral CT warrants further investigation.     

Dependence of Ultrasonic Velocity on Porosity and Pore Shape in Sintered Materials

A new approach to predict the longitudinal and transverse ultrasonic velocities in porous materials is presented. The model is based on a previously derived Young's modulus-porosity correlation assuming spheroidal geometry of the pores. It is also assumed that the Poisson's ratio of porous materials does not change significantly with porosity. The longitudinal and transverse ultrasonic velocities are given as functions of the Young's modulus, Poisson's ratio, density of the pore-free material and of the porosity and axial ratio (z/x) of the spheroidal pores. Experimental data drawn from the literature on different porous sintered materials including SiC, Al₂O₃, YBa₂Cu₃O_7–x , porcelain, sintered iron, Si₃N₄, and sintered tungsten, were used to verify the model. A strong relationship between pore shape and the slope of the ultrasonic velocity–porosity curve was confirmed. In general, the calculated values are in fairly good agreement with the experimental data. When the actual shape (axial ratio) of the pores was known, the approach was shown to predict the experimental data better than a similar model derived by Phani. It is suggested that the present approach, coupled with the measurement of the ultrasonic velocity, may constitute a simple nondestructive technique to gain knowledge of the morphology of the porosity in sintered materials.     

Role of Citric Acid in Delaying Gypsum Precipitation

The comprehension of the mechanisms of nucleation and growth that regulate the gypsum (calcium sulfate dihydrate) precipitation is fundamental to prevent scaling problems. The present paper reports measurements of the induction period for gypsum nucleation when citric acid is added in solution as an additive to retard scale formation. The supersaturation ratio was varied in the interval 2.3‐6.0, the concentration of citric acid ranged from 0.01 to 0.30 g/L, while in all experiments the temperature was fixed to 25°C. The induction period values were compared to those previously obtained, by using the same experimental technique, in the absence of foreign ions in the mother liquor, showing that the citric acid has a strong retarding effect towards gypsum nucleation.     

新的角度，新的实践——ASP．NET 2．0和数据绑定控件

本文讲述了ASP．NET 2．0中用于构建自定义数据绑定控件的工具是如何演变的。     

Gene Mutation Analysis in EGFR Wild Type NSCLC Responsive to Erlotinib: Are There Features to Guide Patient Selection?

Tyrosine kinase inhibitors (TKIs) are very efficacious in non-small-cell lung cancer (NSCLC) patients harboring activating Epidermal Growth Factor Receptor (EGFR) mutations. However, about 10% of EGFR wild type (wt) patients respond to TKI, with unknown molecular mechanisms of sensitivity. We considered a case series of 34 EGFR wt NSCLC patients responsive to erlotinib after at least one line of therapy. Responsive patients were matched with an equal number of non-responsive EGFR wt patients. A panel of 26 genes, for a total of 214 somatic mutations, was analyzed by MassARRAY^® System (Sequenom, San Diego, CA, USA). A 15% KRAS mutation was observed in both groups, with a prevalence of G12C in non-responders (80% vs. 40% in responders). NOTCH1, p53 and EGFR-resistance-related mutations were found more frequently in non-responders, whereas EGFR-sensitizing mutations and alterations in genes involved in proliferation pathways were more frequent in responders. In conclusion, our findings indicate that p53, NOTCH1 and exon 20 EGFR mutations seem to be related to TKI resistance. KRAS mutations do not appear to influence the TKI response, although G12C mutation is more frequent in non-responders. Finally, the use of highly sensitive methodologies could lead to the identification of under-represented EGFR mutations potentially associated with TKI sensitivity.     

Discrepancies between VEGF ?1154 G>A Polymorphism Analysis Performed in Peripheral Blood Samples and FFPE Tissue

Single nucleotide polymorphisms (SNPs) may be associated with the response or toxicity to different types of treatment. Although SNP analysis is usually performed on DNA from peripheral blood, formalin fixed paraffin-embedded (FFPE) tissue is often used for retrospective studies. We analyzed VEGF (−2578C>A, −1498C>T, −1154G>A, −634C>G, +936C>T) and eNOS (+894G>T, −786T>C, VNTR (variable number of tandem repeats) 27bp intron 4) polymorphisms by direct sequencing or Real Time PCR in 237 patients with advanced colorectal cancer. Peripheral blood was used for 153 patients, whereas only FFPE tumor tissue was available for 84 patients. All SNP frequencies were in Hardy-Weinberg Equilibrium (HWE), with the exception of VEGF −1154, which was only in HWE in peripheral blood specimens. We therefore analyzed this SNP in DNA extracted from FFPE tumor tissue compared to FFPE healthy tissue and peripheral blood from 20 patients. Numerous heterozygous patients in peripheral blood DNA were homozygous for the A-allele in both tumor and healthy FFPE tissues. Our findings indicate that, although FFPE tissue might be a suitable specimen for genotyping, VEGF −1154 does not give reliable results on this type of material. As other SNPs may also have this limitation, genotype concordance should first be confirmed by comparing results obtained from FFPE and fresh sample analyses.