Morphological and Elemental Classification of Freshly Emitted Soot Particles and Atmospheric Ultrafine Particles using the TEM/EDS

The Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS) were used to determine morphology and elemental composition of a variety of freshly emitted soot particles (acetylene flame, candle flame, kerosene flame, diesel exhaust, electric arc, plastic burning, styrofoam burning, wood burning [white oak and pine bark], and rice straw burning), which can be possible candidate soot in the ambient atmosphere, and ultrafine particles sampled in urban, industrial, and coastal sites during ultrafine particle formation events (combustion and photochemical events). By using mobility-classified non-refractory ((NH ₄ ) ₂ SO ₄ ) and refractory (Polystyrene latex (PSL) and salt (NaCl)) particles, limitation of the TEM was tested. Data showed that the TEM method can be used to examine shapes of both volatile particles such as (NH ₄ ) ₂ SO ₄ (100 nm) at low, but not high magnification (refer to low and high beam intensity, respectively), and non-volatile particles like NaCl (100 nm) and PSL (84 nm) at either low or high magnification. Distinct differences in morphological properties such as primary particle diameter, fractal dimension, and microstructure were observed among the different types of fresh soot particles. The atmospheric ultrafine particles were classified as agglomerates, sulfate mixtures (spherical), metallic oxides (spherical and polygonal), C-rich refractory (not agglomerated), C-rich non-refractory (not agglomerated), Si-rich (spherical), Na-rich (porous), or P-containing (non-spherical) particles. At the urban Gwangju site, a higher fraction of fresh and aged agglomerates was observed than at other sites. The C-rich non-refractory and sulfate mixtures were often observed in the photochemical event. The C-rich refractory particles were abundant at the Gwangju and Yeosu sites. The coastal Taean site had few agglomerates due to limited anthropogenic combustion source.     

A design system for RFIC: challenges and solutions

The expansion of the market for portable wireless communication devices has given a tremendous push to the development of a new generation of low-power radio frequency integrated circuit (RFIC) products. In this fast-growing environment where time-to-market constraints force tight schedules, having a good design methodology, innovation computer-aided design (CAD) tools, and a well-integrated design system are key factors for success. In this paper, we describe a design system developed to provide the designer with everything necessary to accurately predict the behavior of RFIC devices, including layout and package parasitic effects. We show how important a well-defined and integrated system is to manufacturing a design that meets specifications at the minimum cost, in the minimum time. A close link between schematic, models, and layout is of paramount importance to ensure the accuracy need for low-power RF design. We give an overview of the advanced methods and tools currently available for simulation and noise analysis of RF devices. Finally, we show a design example that obtained first-silicon success     

Correlates of physical activity in a national sample of girls and boys in Grades 4 through 12.

Psychological, biological, social, and physical environmental variables were examined for their association with physical activity of young people. A national sample of 1,504 parents and children in Grades 4–12 were interviewed by telephone. Twenty-two potential determinants were assessed along with an 11-item child physical activity index (α?=?.76). Hierarchical multiple regressions were conducted separately for 6 age–sex subgroups. Percentage of variance explained ranged from 18% for boys in Grades 4–6 to 59% for girls in Grades 10–12. Three variables had strong and consistent associations with the child physical activity index that generalized across subgroups: use of afternoon time for sports and physical activity, enjoyment of physical education, and family support for physical activity. These 3 variables should be targeted for change to promote physical activity in all groups of young people. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Osteoporosis for the allergist

OBJECTIVE: This review is intended to be an authoritative summary of the pathogenesis of osteoporosis, a problem that may be encountered in allergy practice. It also provides an outline for identification of subjects at high risk and directions for their appropriate evaluation, management, and prevention of the disease. DATA SOURCES: References were obtained through a MEDLINE literature search as well as from previous reviews. Relevant articles were critically reviewed and their conclusions were included. RESULTS: Osteoporosis is a relatively common disease that is associated with significant morbidity and mortality. The management and prevention of osteoporosis have been improved by an increased awareness of the magnitude of the problem, a better understanding of the pathogenesis, development of a better technique for assessment of bone mineral density, and the availability of specific medications. With the increase in human life-span and the increasing use of glucocorticosteroids for a wide variety of diseases, the incidence of osteoporosis has been on the rise. CONCLUSION: Glucocorticosteroids are the most common medications that cause or contribute to the pathogenesis of osteoporosis and have been widely used in allergy practice. It is important for physicians to appreciate the current basic understanding of osteoporosis and to be able to identify patients at high risk for this serious disorder, and to initiate appropriate intervention at a sufficiently early time to be effective. Medications for treatment and prevention of osteoporosis include: calcium, vitamin D, estrogen, bisphosphonates, calcitonin, and others are reviewed in this article.     

Microbial Abundance in the Schwertmannite Formed in a Mine Water Treatment Plant

Treatment of acidic iron- and sulfate-rich mine waters in a pilot plant at the opencast lignite mining pit Nochten (Lusatia, Germany) involves microbial iron oxidation and subsequent precipitation of the iron-oxyhydroxysulfate schwertmannite. To determine if recirculation of schwertmannite can stabilize and optimize the oxidation process, cell number, viability, and diversity of the bacterial community in schwertmannite precipitated on carrier material and stored schwertmannite were analyzed. In schwertmannite on carrier material, the total cell number decreased slightly with increasing mineral depth, whereas the percentage of viable cells decreased significantly. The microbial community, investigated by fluorescence-in-situ-hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP), revealed the presence of the iron-oxidizing bacterium “Ferrovum” sp. and relatives of Gallionella, independent of mineral depth. Analysis of the viability of microorganism in stored schwertmannite indicated an almost constant percentage of viable cells over 42 days.     

Rearrangement/Fragmentation Reactions of Oligosilanes with Aluminum Chloride

Reinvestigation of the Lewis acid catalyzed rearrangement of some open-chain permethyloligosilanes with the Al(Fe)Cl(3) catalyst system exhibited several cases of additional reactivity: namely, a fragmentation/cyclization reaction. Introduction of (trimethylsilyl)methyl substituents into the oligosilane substrates strongly facilitated this reaction, yielding cyclic or bicyclic carbacyclosilanes. Investigations concerning the composition of the catalyst system indicated that the incorporation of about 0.1% FeCl(3) into the AlCl(3) lattice provided an effective catalyst.     

Australia's housing choices: Retrospect and prospect

This article identifies issues around the Auckland Region's strategy for urban intensification and discusses the ensuing policy implications. Medium density housing forms an important element of the strategy for growth management. Implications for its success are primarily drawn from research into a major housing development in Waitakere City. It is argued that for ideological, political and technical reasons the strategy could be easily undermined. The article also suggests that something of a paradigm shift is underway in urban planning.     

Activity of quassinoids as antifeedants against aphids

A series of quassinoids was tested for antifeedant activity against the aphidMyzus persicae (Hemiptera, Aphididae). Isobrucein B, brucein B and C, glaucarubinone, and quassin decreased feeding at concentrations down to 0.05% and isobrucein A was effective at 0.01%. Only quassin showed no phytotoxic effects and is therefore the most promising compound for further development.     

Zeolite Formation in Class F Fly Ash Blended Cement Pastes

Zeolite formation in Class F fly ash blended cement pastes is under investigation. A Na–P type zeolite and Zeolite Y were synthesized from Class F fly ash and NaOH solution after 2 days of aging at room temperature and 6 days of curing at 80°C. However, no zeolites formed when KOH was used. In additional experiments, a Na–P type zeolite, Zeolite Y, and chabazite developed in cement pastes blended with Class F fly ash and NaOH solution which had been aged 2 days at room temperature and then cured 6 days at temperatures ranging from room temperature to 90°C. Seeding the pastes with natural zeolites was also investigated.     

Electrophoretic deposition of carbon nanotubes

Electrophoretic deposition (EPD) has been gaining increasing interest as an economical and versatile processing technique for the production of novel coatings or films of carbon nanotubes (CNTs) on conductive substrates. The purpose of the paper is to present an up-to-date comprehensive overview of current research progress in the field of EPD of CNTs. The paper specifically reviews the preparation and characterisation of stable CNT suspensions, and the mechanism of the EPD process; it includes discussion of pure CNT coatings and CNT/nanoparticle composite films. A complete discussion of the EPD parameters is presented, including electrode materials, deposition time, electrode separation, deposition voltage and resultant electric field. The paper highlights potential applications of the resulting CNT and CNT/composite structures, in areas such as field emission devices, fuel cells, and supercapacitors.