Miniaturised two-stage balanced Ku-band CPW MMIC amplifier using impedance transforming couplers

A two-stage balanced Ku-band coplanar waveguide amplifier design is presented which has been miniaturised by using impedance transforming couplers which considerably reduce the required matching networks to the MESFETs. The amplifier, measuring only 2*1.7 mm/sup 2/, exhibits a gain of 13.7 dB with less than +or-0.2 dB of ripple over the range 14-16 GHz.<>     

Uniplanar techniques for monolithic microwave integrated circuits

`Uniplanar' techniques have recently been introduced for the design of monolithic microwave integrated circuits (MMICs). The aim of these techniques is to achieve a higher level of integration of circuitry and to overcome the need for through-substrate via holes and the related back-face processing steps. This is achieved by using coplanar waveguide (CPW), slotline, and miniature `thin-film microstrip' transmission-line media as opposed to conventional microstrip. The design and performance of a number of uniplanar MMIC couplers, amplifiers, and other test circuits fabricated using the GEC-Marconi (Caswell) foundry are described     

Tobacco particulate matter is more potent than nicotine at upregulating nicotinic receptors on SH-SY5Y cells.

The effect of total particulate matter (TPM) from cigarette smoke on the expression and binding properties of nicotinic acetylcholine receptors (nAChRs) was investigated using a human neuroblastoma cell line (SH-SY5Y). TPM but not nicotine on its own inhibited cell growth at nicotine concentrations above 5 microM. To examine effects on nAChR expression, intact cells were incubated with 3H-epibatidine, and a Bmax of 13 fmoles/10(5) cells (7.8 x 10(4) binding sites/cell) was measured in unexposed cells as well as in cells treated with 2 microM nicotine alone or with TPM containing 2 microM nicotine. Using Scatchard analysis, we measured a Kd of 0.3 nM for 3H-epibatidine binding to nAChRs. This Kd was increased to 1.3 nM by addition of nicotine or TPM extract, both at 2 microM nicotine. Bmax, however, was unaffected, suggesting competitive binding of nicotine to its receptor. Short-term and prolonged 3-day exposures of SH-SY5Y cells to either TPM or nicotine at nicotine concentrations ranging from 0.2 microM to 20 microM increased specific binding, suggesting upregulation of nAChR expression. Most significant, binding was consistently greater in cells pretreated with TPM than in cells pretreated with nicotine. We conclude that TPM contains compounds that are toxic to cells at high concentrations (cell growth inhibition) but that do not compete with nicotine for binding to nAChRs (Scatchard analysis). These non-nicotinic compounds are capable of increasing the expression of one or more of the nAChR subunits. Furthermore, our cell culture assay provides a useful in vitro model for assessing the relative addictiveness of different tobacco products, including that of non-nicotine components.     

澳大利亚零碳展示房

1背景简介在澳大利亚,民用住宅已经成为碳排放增长较快的板块之一.预计在2020年,民用住宅将比1990年增加61％,因此,想要达到澳大利亚的以2000年为基准,在2020年和2050年相继减排5％和80％的目标,需要对将建的和已建的民用住宅进行大量的碳减排.2007年,为了倡导民用住宅的减排和维护国家未来的持续发展,澳大利亚联邦科学院( CSIRO)的能源转型研究中心设立了澳大利亚零碳房( AusZEH)项目,致力于展示和评估适用于澳大利亚的低碳民用住宅技术.     

An Introduction to the Community of Professors: The Engineering Education Scholars Workshop

It can be difficult for new faculty to get the information they need on issues such as teaching, advising, and setting up a research program. While some have excellent mentors, others have come to rely on trial and error or word of mouth. In 1996, the NSF Engineering Education Scholars Workshop began at Carnegie Mellon University to address the needs of new and future engineering faculty by:

• ? providing professional teaching development;
• ? offering guidance in supervising graduate students and conducting research;
• ? discussing likely engineering education and research challenges in the 21^st century; and
• ? providing intellectual and social support with colleagues.

After three years, a significant amount of knowledge and experience has been gathered by the workshop co‐chairs. This paper details the structure of the workshop and discusses the underlying principles and implementation to provide guidance for those planning similar workshops.     

Serum concentrations of soluble adhesion molecules in patients with colorectal cancer

The concentrations of the soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 48 patients with colorectal cancer before treatment, and their relation to clinical, histological and routine laboratory parameters was examined. Data were collected on tumour stage at presentation, presence and sites of metastatic disease, tumour pathology and results of routine laboratory tests. Serum concentrations of ICAM-1 and VCAM-1 were significantly elevated in the patients with colorectal cancer in comparison with a group of healthy subjects (P < 0.00001). Levels of circulating ICAM-1 and VCAM-1 were increased both in patients with local and those with metastatic disease. Although elevated in some patients soluble E-cadherin and E-selectin concentrations were not significantly elevated compared with the control group (P = 0.71 and P = 0.052 respectively). The levels of circulating ICAM-1 were significantly correlated with those of VCAM-1 and E-selectin. A correlation was also found between the serum concentrations of E-selectin and ICAM-1 and alkaline phosphatase, total white cell count and platelet count. VCAM-1 was positively correlated with age and negatively with degree of tumour differentiation and haemoglobin concentration. The biological implications and possible clinical relevance of these findings are discussed.     

Structure–physical property relationships in peroxide-cured butadiene–styrene copolymers

Structure–physical property relationships in high-vinyl butadiene–styrene copolymers have been determined for samples cured with dicumyl peroxide under the same conditions. Three different structures, butadiene–styrene–butadiene (B–S–B) triblocks, butadiene–styrene (B–S) diblocks, and random butadiene–styrene copolymers, have been examined. Flexural modulus increases with increasing styrene content owing to the inherent stiffness of a polystyrene backbone. Swelling increases whereas hardness and heat distortion temperature decrease with increasing styrene content. This behavior is explained by the decrease in crosslink density with increasing styrene content in all structures. Heat distortion temperatures of the B–S–B and B–S networks are superior to the heat distortion properties of the random structures. The B–S–B structure is the most solvent resistant, followed by the random copolymers, with the B–S structures swelling to the greatest extent. Swelling differences between the B–S–B and random networks decrease with increasing styrene content, while swelling differences between the B–S–B and B–S networks increase with increasing styrene content. These results are explained by the nature of the crosslinking reaction and the number of loose ends present in each network.     

Selective extraction and characterization of a histidine-phosphorylated peptide using immobilized copper(II) ion affinity chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Phosphorylation is the predominant posttranslational modification involved in regulating enzymatic activity and mediating signal transduction in prokaryotic and eukaryotic cells. Selective enrichment of phosphorylated peptides prior to mass spectrometric analysis facilitates identification of phosphorylated proteins, determination of specific phosphorylated residues, and characterization of the conditions under which phosphorylation occurs. Such protocols have been established for peptides containing residues that form phosphoesters, such as serine and threonine, using immobilized metal-ion affinity chromatography. Despite the importance of histidine phosphorylation in two-component signal transduction pathways, similar protocols for peptides containing phosphorylated histidine (P-His) residues have proven elusive, due to the instability of these modifications and the propensity of unphosphorylated histidines to interact with immobilized metals ions. We describe a method for the selective extraction of a P-His-containing peptide using immobilized copper(II) ions and disposable metal-chelating pipet tips (ZipTipMC, Millipore). The method is contingent upon pH-dependent interactions between the phosphate group and immobilized copper(II) ions. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with postsource decay confirms the identity and phosphorylation state of the extracted peptide. Peptides containing unphosphorylated histidine residues or other phosphorylated amino acids are not retained, demonstrating the specificity of the method for P-His-containing peptides.