Metallization of branched DNA origami for nanoelectronic circuit fabrication.

This work examines the metallization of folded DNA, known as DNA origami, as an enabling step toward the use of such DNA as templates for nanoelectronic circuits. DNA origami, a simple and robust method for creating a wide variety of shapes and patterns, makes possible the increased complexity and flexibility needed for both the design and assembly of useful circuit templates. In addition, selective metallization of the DNA template is essential for circuit fabrication.

Evidence for a collective intelligence factor in the performance of human groups.

Psychologists have repeatedly shown that a single statistical factor--often called "general intelligence"--emerges from the correlations among people's performance on a wide variety of cognitive tasks. But no one has systematically examined whether a similar kind of "collective intelligence" exists for groups of people. In two studies with 699 people, working in groups of two to five, we find converging evidence of a general collective intelligence factor that explains a group's performance on a wide variety of tasks.

The investigation of a prolonged APTT with specific clotting factor assays is unnecessary if an APTT with Actin FS is normal.

Introduction: An isolated prolongation to the activated partial thromboplastin time (APTT) can be caused by the presence of the lupus anticoagulant or an intrinsic or contact factor deficiency, of which only deficiencies of factors VIII, IX or XI are associated with bleeding. Our local protocol states that further investigation of a prolonged APTT by specific assays of FVIII, FIX and FXI should only be undertaken where the APTT with one reagent (Synthasil) is more than 3 s prolonged, and further investigation by an APTT with a second reagent (Actin FS) is also prolonged, unless there is a history of bleeding in the patient, in which case assays are indicated irrespective of the APTT.

Methods: We retrospectively reviewed the results of all APTTs performed over a 36-month period to evaluate whether strictly applying our protocol would reduce the number of unnecessary clotting factor assays performed, without leaving patients with potentially significant bleeding disorders undiagnosed.

Microdevices integrating affinity columns and capillary electrophoresis for multibiomarker analysis in human serum.

Biomarkers in human body fluids have great potential for use in screening for diseases such as cancer and diabetes, diagnosis, determining the effectiveness of treatments, and detecting recurrence. Present 96-well immunoassay technology effectively analyzes large numbers of samples; however, this approach is more expensive and less time effective on single or a few samples. In contrast, microfluidic systems are well suited for assaying small numbers of specimens in a point-of-care setting, provided suitable procedures are developed to work within peak capacity constraints when analyzing complex mixtures like human blood serum.

Contactless conductivity detection of small ions in a surface micro-machined CE chip.

A microchip is presented which is capable of CE separations and is built using exclusively thin film deposition techniques, fully compatible with microelectronics batch processing. Standard photolithography provides control of the spacing between electrodes used in conductivity measurement and overall channel geometry. Fluid channels are arranged as a double-T injector with a 50 microm offset at the arm intersection.

The management of myringotomy tubes in pediatric cochlear implant recipients.

Objective: To investigate the impact of myringotomy tubes (MTs) on outcomes for pediatric cochlear implant (CI) recipients.

Design: Retrospective case-control chart review.

Setting: Tertiary care pediatric hospital.

Integrated Multi-process Microfluidic Systems for Automating Analysis.

Microfluidic technologies have been applied extensively in rapid sample analysis. Some current challenges for standard microfluidic systems are relatively high detection limits, and reduced resolving power and peak capacity compared to conventional approaches. The integration of multiple functions and components onto a single platform can overcome these separation and detection limitations of microfluidics.

Investigation of neuromuscular abnormalities in neurotrophin-3-deficient mice.

Neurotrophin-3 (NT-3) is a trophic factor that is essential for the normal development and maintenance of proprioceptive sensory neurons and is widely implicated as an important modulator of synaptic function and development. We have previously found that animals lacking NT-3 have a number of structural abnormalities in peripheral nerves and skeletal muscles. Here we investigated whether haploinsufficiency-induced reduction in NT-3 resulted in impaired neuromuscular performance and synaptic function.

Selective trapping and concentration of nanoparticles and viruses in dual-height nanofluidic channels.

Nanofluidic systems offer advantages for chemical analysis, including small sample volumes, size-selective particle trapping, sample concentration and the ability to separate and detect single molecules. Such systems can be fabricated using planar nanochannels, which rely on standard photolithographic techniques. Nanochannel fluid flow can be driven by capillary action, which benefits from simple injection and reasonably high flow rates.

A gene expression signature of invasive potential in metastatic melanoma cells.

Background: We are investigating the molecular basis of melanoma by defining genomic characteristics that correlate with tumour phenotype in a novel panel of metastatic melanoma cell lines. The aim of this study is to identify new prognostic markers and therapeutic targets that might aid clinical cancer diagnosis and management.

Principal Findings: Global transcript profiling identified a signature featuring decreased expression of developmental and lineage specification genes including MITF, EDNRB, DCT, and TYR, and increased expression of genes involved in interaction with the extracellular environment, such as PLAUR, VCAN, and HIF1a.

Polymerase chain reaction based scaffold preparation for the production of thin, branched DNA origami nanostructures of arbitrary sizes.

Designs for DNA origami have previously been limited by the size of the available single-stranded genomes for scaffolds. Here we present a straightforward method for the production of scaffold strands having various lengths, using polymerase chain reaction amplification followed by strand separation via streptavidin-coated magnetic beads. We have applied this approach in assembling several distinct DNA nanostructures that have thin ( approximately 10 nm) features and branching points, making them potentially useful templates for nanowires in complex electronic circuitry.

Compact vibration isolation and suspension for Australian International Gravitational Observatory: performance in a 72 m Fabry Perot cavity.

This paper describes the first demonstration of vibration isolation and suspension systems, which have been developed with view to application in the proposed Australian International Gravitational Observatory. In order to achieve optimal performance at low frequencies new components and techniques have been combined to create a compact advanced vibration isolator structure. The design includes two stages of horizontal preisolation and one stage of vertical preisolation with resonant frequencies approximately 100 mHz.

Polymer microchip CE of proteins either off- or on-chip labeled with chameleon dye for simplified analysis.

Microchip CE of proteins labeled either off- or on-chip with the "chameleon" CE dye 503 using poly(methyl methacrylate) microchips is presented. A simple dynamic coating using the cationic surfactant CTAB prevented nonspecific adsorption of protein and dye to the channel walls. The labeling reactions for both off- and on-chip labeling proceeded at room temperature without requiring heating steps.

Genotoxic stress-induced nuclear localization of oncoprotein YB-1 in the absence of proteolytic processing.

Y-box-binding protein 1 (YB-1) is an oncogenic transcription factor whose overexpression and nuclear localization is associated with tumor progression and drug resistance. Transcriptional activation of YB-1 in response to genotoxic stress is believed to occur in the cytoplasm through sequence-specific endoproteolytic cleavage by the 20S Proteasome, followed by nuclear translocation of cleaved YB-1. To study the proteolysis model, we developed a two-step affinity purification of endogenous YB-1 protein species and characterized the products using mass spectrometry.

Integrated microfluidic device for serum biomarker quantitation using either standard addition or a calibration curve.

Detection and accurate quantitation of biomarkers such as alpha-fetoprotein (AFP) can be a key aspect of early stage cancer diagnosis. Microfluidic devices provide attractive analysis capabilities, including low sample and reagent consumption, as well as short assay times. However, to date microfluidic analyzers have relied almost exclusively on calibration curves for sample quantitation, which can be problematic for complex mixtures such as human serum.

Bilinear electric field gradient focusing.

Electric field gradient focusing (EFGF) uses an electric field gradient and a hydrodynamic counter flow to simultaneously separate and focus charged analytes in a channel. Previously, most EFGF devices were designed to form a linear field gradient in the channel. However, the peak capacity obtained using a linear gradient is not much better than what can be obtained using conventional CE.

A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose.

We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose (HPC) in a spin-coated thin film on the surface. Poly(methyl methacrylate-8.5-methacrylic acid), a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces.

DNA-templated nanofabrication.

Nanofabrication, or the organizational control over matter at the nanometre scale, is an intriguing scientific challenge requiring multidisciplinary tools for its solution. DNA is a biomolecule that can be combined with other nanometre-scale entities through chemical self-assembly to form a broad variety of nanomaterials. In this tutorial review we present the principles that allow DNA to interact with other chemical species, and describe the challenges and potential applications of DNA as a template for making both biological and inorganic features with nanometre resolution.

Performance optimization in electric field gradient focusing.

Electric field gradient focusing (EFGF) is a technique used to simultaneously separate and concentrate biomacromolecules, such as proteins, based on the opposing forces of an electric field gradient and a hydrodynamic flow. Recently, we reported EFGF devices fabricated completely from copolymers functionalized with poly(ethylene glycol), which display excellent resistance to protein adsorption. However, the previous devices did not provide the predicted linear electric field gradient and stable current.

Phase-changing sacrificial layers in microfluidic devices: adding another dimension to separations.

The use of polymers in microchip fabrication affords new opportunities for the development of powerful, miniaturized separation techniques. One method in particular, the use of phase-changing sacrificial layers, allows for simplified designs and many additional features to the now standard fabrication of microchips. With the possibility of adding a third dimension to the design of separation devices, various means of enhancing analysis now become possible.

Affinity monolith preconcentrators for polymer microchip capillary electrophoresis.

Developments in biology are increasing demands for rapid, inexpensive, and sensitive biomolecular analysis. In this study, polymer microdevices with monolithic columns and electrophoretic channels were used for biological separations. Glycidyl methacrylate-co-ethylene dimethacrylate monolithic columns were formed within poly(methyl methacrylate) microchannels by in situ photopolymerization.