The Red-Shift of Ultraviolet Spectra and the Relation to Optical Basicity of Ce-Doped Alkali Rare-Earth Phosphate Glasses

The ultraviolet absorption and emission spectra of Ce³⁺ doped phosphate glasses based on gadolinium and sodium phosphates are studied in the present work. Compared with the cerium-free phosphate glass matrixes, CePO₄ doping shifts the ultraviolet absorption edge of glasses into the longer wavelength because of the 4f–5d absorption transition of Ce³⁺. The emission spectra correlate such red-shift with glass compositions. Explanations are based on variation in the optical basicity of glasses, which corresponds not only to the alkali content but also to the O/P ratio. The latter is proportional to the number of nonbridging oxygen in the oxyanion unit (PO₄), and most likely plays an overwhelming role in the overall optical basicity of glasses.     

Multistep Model of Cervical Cancer: Participation of miRNAs and Coding Genes

Aberrant miRNA expression is well recognized as an important step in the development of cancer. Close to 70 microRNAs (miRNAs) have been implicated in cervical cancer up to now, nevertheless it is unknown if aberrant miRNA expression causes the onset of cervical cancer. One of the best ways to address this issue is through a multistep model of carcinogenesis. In the progression of cervical cancer there are three well-established steps to reach cancer that we used in the model proposed here. The first step of the model comprises the gene changes that occur in normal cells to be transformed into immortal cells (CIN 1), the second comprises immortal cell changes to tumorigenic cells (CIN 2), the third step includes cell changes to increase tumorigenic capacity (CIN 3), and the final step covers tumorigenic changes to carcinogenic cells. Altered miRNAs and their target genes are located in each one of the four steps of the multistep model of carcinogenesis. miRNA expression has shown discrepancies in different works; therefore, in this model we include miRNAs recording similar results in at least two studies. The present model is a useful insight into studying potential prognostic, diagnostic, and therapeutic miRNAs.     

Microindentation and Inverse Analysis to Characterize Elastic-Plastic Properties for Thermal Sprayed Ti2AlC and NiCoCrAlY

Elastic-plastic material properties for HVOF sprayed Ti₂AlC (sprayed with Maxthal 211 powder) and plasma sprayed NiCoCrAlY coatings were investigated using modeling and experimental Berkovich microindentation. Optical microstructure evaluations were also performed. The theories of Hertz, Oliver and Pharr were combined with finite element analysis for extracting the material properties. Empirically based material models for both thermal sprayed Ti₂AlC and NiCoCrAlY coatings are proposed.     

Morphology of mucosa‐associated lymphoid tissue in odontocetes

This study describes the mucosa‐associated lymphoid tissue (MALT) in odontocetes from the Brazilian coast and freshwater systems. Seven species were evaluated and tissue samples were analyzed by light, scanning and transmission electron microscopy, and immunohistochemistry. Laryngeal tonsil was a palpable oval mass located in the larynx, composed of a lymphoepithelial complex. Dense collections of lymphocytes were found in the skin of male fetus and calf. Clusters of lymphoid tissue were found in the uterine cervix of a reproductively active juvenile female and along the pulmonary artery of an adult female. Lymphoid tissues associated with the gastrointestinal tract were characterized by diffusely arranged or organized lymphocytes. The anal tonsil was composed of an aggregate of lymphoid tissue occurring exclusively in the anal canal, being composed of squamous epithelium branches. MALT was present in different tissues and organic systems of cetaceans, providing constant protection against mucosal pathogens present in their environment.     

Proactive assembly systems-realising the potential of human collaboration with automation

Manufacturing competitiveness frequently relies on company ability to rapidly reconfigure their assembly systems. This paper introduces assembly system proactivity, a concept based on interrelated levels of automation, human competence, and information handling. Increased and structured human involvement contributes to increased system ability to proactively address predicted and unpredicted events. Correct involvement of human operators will utilize the combined potential of human and technical capabilities, providing cost-efficient assembly system solutions. The ProAct project is developing proactive assembly system models and evaluates proactive, feature-based solutions. Focus is on realising the potential of cost-efficient and semi-automated systems with relevant human involvement, i.e. highly skilled operators who add flexibility and functionality © 2009 Elsevier Ltd. All rights reserved.     

Morphological observations of ampullae of lorenzini in Squatina guggenheim and S. occulta (chondrichthyes, elasmobranchii, squatinidae)

We have conducted a morphological study of the ampullae of Lorenzini on two shark species from Squatina Genus. In both species, S. guggenheim and S. occulta, the ampullae were observed like small pores scattered in the head region similar to other species of the Chondrichthyes Class. However, differently of the other species a greatest density of ampullae of Lorenzini was observed along of the body surface. After fixation using 10% formaldehyde, the ampullae were removed and processed for light and scanning electron microscopy. Macroscopically, the two shark species differed by the presence of dorsal spines that appeared from the head to the first dorsal fin in S. guggenheim and were absent in S. occulta. Microscopically, there were no differences between the ampullae of Lorenzini channels in these two species. The wall of the ampulla was formed by a simple squamous epithelium. Bands of connective tissue, hyaline cartilage and collagen fibers were found between the ampulla and the skeletal striated muscle layer. Nerve branches responsible for conducting signal pulses to the central nervous system were visible between the muscle and connective tissue layers. Using scanning electron microscopy and histological analysis, we found that the channels were twisted and positioned parallel to the skin. The inside of the channels contained a large amount of a gelatinous secretion composed by polysaccharides. Therefore, we conclude that the morphological combination of extended distribution of the ampullae of Lorenzini and the body shape may represent an adaptation of these species to their way of life. Microsc. Res. Tech. 75:1213–1217, 2012. © 2012 Wiley Periodicals, Inc.     

Polyacrylamide-treated kaolin: A fabric study

Particle interactions, and in turn fabric, determine the behavior of clay mineral particle systems. Polymers with deliberately chosen characteristics, such as molecular mass and ionic type, can be utilized to manipulate clay fabric. The purpose of this study is to understand fabric development in a clay–polymer system, specifically kaolin–polyacrylamide systems over a wide range of solids content. Methodologies include sedimentation tests (low solids content), viscosity measurements (moderate solids content), and liquid limit measurements (high solids content), and are conducted to determine variation in fabric for kaolin–polyacrylamide systems at various concentrations, molecular mass and ionic types of polyacrylamide. Fabric development is verified using scanning electron microscopy (SEM). Results show that the polymer charge type impacts the resulting fabric formation only at polymer concentrations above a threshold concentration. Floc/aggregate size and density tend to increase with increasing polyacrylamide concentration, while high molecular-mass polyacrylamides tend to induce the formation of open flocculated structure. The most likely particle association in the presence of nonionic polyacrylamides is face-to-face association due to polymer bridging. A relationship is found between polymer characteristics, solids contents, and micro-scale particle arrangement. This study is relevant to the emerging field of engineered soil fabrics.