SAI Consultants

The work of Bangkok-based Bundit Chulasai runs the full gamut of building types from palace restorations to private houses, resorts and even discount supermarkets. Brian McGrath describes how Chulasai's ‘successful “adaptive practice” with SAI Consultants creates a critical mirror to reflect the last 30 years of Thai society’. Copyright © 2009 John Wiley & Sons, Ltd.     

Moving huge scientific datasets over the Internet

Modern scientific experiments can generate hundreds of gigabytes to terabytes or even petabytes of data that may be maintained in large numbers of relatively small files. Frequently, these data must be disseminated to remote collaborators or computational centers for data analysis. Moving this dataset with high performance and strong robustness and providing a simple interface for users are challenging tasks. We present a data transfer framework comprising a high‐performance data transfer library based on GridFTP, an extensible data scheduler with four data scheduling policies, and a GUI that allows users to transfer their dataset easily, reliably, and securely. This system incorporates automatic tuning mechanisms to select at runtime the number of concurrent threads to be used for transfers. Also included are restart mechanisms for handling client, network, and server failures. Experimental results indicate that our data transfer system can significantly improve data transfer performance and can recover well from failures. Copyright © 2011 John Wiley & Sons, Ltd.     

Ionizable isotopic labeling reagent for relative quantification of amine metabolites by mass spectrometry

A powerful approach to relative quantification by mass spectrometry is to employ labeling reagents that target specific functional groups in molecules of interest. A quantitative comparison of two or more samples may be readily accomplished by using a chemically identical but isotopically distinct labeling reagent for each sample. The samples may then be combined, subjected to purification steps, and mass analyzed. Comparison of the signal intensities obtained from the isotopically labeled variants of the target analyte(s) provides quantitative information on their relative concentrations in the sample. In this report, we describe the synthesis and use of heavy and light isotopic forms of methyl acetimidate for the relative quantification of amine-containing species. The principal advantages of methyl acetimidate as a labeling reagent are that the reaction product is positively charged and hydrophobicity is increased, both of which enhance electrospray ionization efficiency and increase detection sensitivity. The quantitative nature of the analysis was demonstrated in model metabolomics experiments in which heavy and light labeled Arabidopsis extracts were combined in different ratios. Finally, the labeling strategy was employed to determine differences in the amounts of amine-containing metabolites for Arabidopsis seeds germinated under two different conditions.     

Self-assembled stripe patterns of CdS nanorods

Sterically stabilized CdS nanorods, 3-5 nm in diameter with aspect ratios ranging from 4 to 15, were observed to self-align into networks of stripes several micrometers long when drop-cast from dispersions at submonolayer coverage. The stripes are two to three nanorods thick with nanorods assembled side-by-side with their long axes parallel to the stripe direction. Energetic forces between nanorods, such as van der Waals and dipole-dipole attractions, favor parallel nanorod alignment; however, we propose that pattern formation is kinetically limited, or mediated, by solvent evaporation.     

Sequential reactions with amine-terminated monolayers and isolated molecules on H/Si(111)

A simple method for preparing monolayers with terminal amine functionality is demonstrated. A gas-phase photochemical reaction of 1,3-diaminopropane with a H-terminated Si(111) surface results in the molecules covalently attaching to the surface, primarily through the formation of a Si--N bond. These monolayers are characterized by scanning tunneling microscopy (STM) and high-resolution electron energy loss spectroscopy (HREELS). The reactivity of the terminal amine is confirmed by exposing the monolayer to benzaldehyde, resulting in the formation of an imine link and the grafting of phenyl rings onto the surface. For short irradiation times, this reaction leads to the formation of isolated amine groups on an otherwise pristine H-terminated surface. STM and HREELS studies of the benzaldehyde reaction on these low-coverage surfaces (less than 0.005 monolayers) indicate that the reaction is restricted to the reactive amine groups, leaving the remainder of the surface unaffected. This simple approach for a sequential coupling reaction is expected to facilitate attachment of more complex molecules (molecular switches, biomolecules) for single-molecule STM studies.     

The effects of atmospheric aging on a hybrid polymer matrix composite

The effect of thermal exposure in an atmospheric environment for up to 1 year on the flexural performance, under both static and fatigue loading, of a glass fiber/carbon fiber hybrid polymer matrix composite material was evaluated. It was found that exposure to a temperature near, but below, the glass transition temperature resulted in diminished flexure strength as well as reduced fatigue performance. The magnitude of property reduction was, in general, proportional to the amount of aging time, and was found to be dictated by the dominant aging mechanism. Scanning electron microscopy revealed that the modest reduction in mechanical properties at intermediate aging times was predominantly attributed to thermal oxidation, while for longer aging times thermal aging (dimensional relaxation) was the primary cause for the substantial reduction. Dimensional relaxation of the composite was measured at several isothermal aging temperatures, from which, the activation energy of the aging process was determined. This work provides insight into the evolution of mechanical properties as a function of aging time in an atmospheric environment for a hybrid polymer matrix composite.     

Osteoblast-like cell response to calcium phosphate coating chemistry and morphology on etched silicon surfaces

Being able to control the behaviour of osteoblast-like cells on a surface may provide a genuine insight into the material surface characteristics and help in creating a successful coating/cell interface. The possibility of creating a micro-environment that can induce proliferation, differentiation and mineralisation of bone cells in vitro, by successfully combining both chemistry and topography of a micro-fabricated substrate is an area that requires a multi-disciplinary approach. Utilising sputter deposition, a process that lends itself to high processability, in conjunction with photolithography allowing for the creation of highly repeatable etched surfaces, we aim to provide a successful combination of chemistry and topography. Correlating the substrate conditions with resultant osteoblast biological function and activity can ultimately be used with a view to modulating the behavior of osteoblast-like cells in vitro.