Micro Total Analysis Systems ’98:Proceedings of the μTAS ’98 Workshop, held in Banff, Canada, 13–16 October 1998

Micro-TAS '98 is the third of a series of symposia initiated by MBSA (University of Twente) in 1994, on the subject of miniaturizing, and integrating within a monolithic structure, the chemical, biochemical and biological procedures commonly used for analysis and synthesis. The primary tool used to develop micro-total analysis systems (mu- TAS) has been micro-photolithographic patterning and micromachining. These powerful tools of Micro System Technology (MST or MEMS) have been applied in highly imaginative ways to develop microchip chemical arrays, fully integrated pump and fluid manifolds, and electrokinetically driven micro-channel systems to be used for genetic analysis, clinical diagnostics and environmental monitoring, and to integrate reactions as diverse as the polymerase chain reaction (PCR) and the large volume, partial oxidation of ammonia. This text illustrates the rapid expansion of the field, the extensive industrial involvement, the increasing number of participating researchers, the expanding range of concepts and applications that utilize MST and microfluidic devices, and new MST-compatible plastic micro-machining to meet the needs of the life science community. This volume contains the proceedings of the Third International Symposium on Micro-Total Analysis Systems, mu-TAS '98, held on October 13-16 in Banff, Alberta, Canada. State-of-the-art invited and contributed papers presented by the world's leading mu- TAS research groups provide a highly informative picture of the growth since 1994 and of the promising future of this exciting and rapidly growing field

Centrifugal blood sample preparation for metabolite derivatization and analysis by solid matrix laser desorption/ionization mass spectrometry (SMALDI-MS)

A microfluidic approach is developed to automate and simplify multiplexed metabolite assays. Solid matrix assisted laser desorption ionization mass spectrometry (SMALDI-MS) on nanoporous thin films is suitable for analyzing small molecules, particularly metabolites, with a simple spot test. We present a system for blood sample preparation for metabolite analysis using centrifugal fluidics, coupled with derivatization and SMALDI-MS. This centrifugal microfluidic device enables semi-automated on-chip cleanup of blood samples, delivering a clean matrix for MS detection. A derivatization reagent is applied in our work to label the target molecules with fluorous affinity tags, so that higher S/N is observed by SMALDI-MS

Miniaturization of Chemical Analysis Systems – A Look into Next Century's Technology or Just a Fashionable Craze?

Miniaturization of already existing techniques in on-line analytical chemistry is an alternative to compound-selective chemical sensors. Theory points in the direction of higher efficiency, faster analysis time, and lower reagent consumption. Micromachining, a well known photolithographic technique for structures in the micrometer range, is introduced and documented with structures as examples for flow injection analysis, electrophoresis, and a detector cell

Bright and Fast Multicoloured Voltage Reporters via Electrochromic FRET

Genetically encoded fluorescent reporters of membrane potential promise to reveal aspects of neural function not detectable by other means. We present a palette of multicoloured brightly fluorescent genetically encoded voltage indicators with sensitivities from 8–13% ΔF/F per 100 mV, and half-maximal response times from 4–7 ms. A fluorescent protein is fused to an archaerhodopsin-derived voltage sensor. Voltage-induced shifts in the absorption spectrum of the rhodopsin lead to voltage-dependent nonradiative quenching of the appended fluorescent protein. Through a library screen, we identify linkers and fluorescent protein combinations that report neuronal action potentials in cultured rat hippocampal neurons with a single-trial signal-to-noise ratio from 7 to 9 in a 1 kHz imaging bandwidth at modest illumination intensity. The freedom to choose a voltage indicator from an array of colours facilitates multicolour voltage imaging, as well as combination with other optical reporters and optogenetic actuators.Chemistry and Chemical BiologyEngineering and Applied SciencesPhysic

Ground and In-Flight Calibration of the OSIRIS-REx Camera Suite

The OSIRIS-REx Camera Suite (OCAMS) onboard the OSIRIS-REx spacecraft is used to study the shape and surface of the mission’s target, asteroid (101955) Bennu, in support of the selection of a sampling site. We present calibration methods and results for the three OCAMS cameras—MapCam, PolyCam, and SamCam—using data from pre-flight and in-flight calibration campaigns. Pre-flight calibrations established a baseline for a variety of camera properties, including bias and dark behavior, flat fields, stray light, and radiometric calibration. In-flight activities updated these calibrations where possible, allowing us to confidently measure Bennu’s surface. Accurate calibration is critical not only for establishing a global understanding of Bennu, but also for enabling analyses of potential sampling locations and for providing scientific context for the returned sample

All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins

All-optical electrophysiology—spatially resolved simultaneous optical perturbation and measurement of membrane voltage—would open new vistas in neuroscience research. We evolved two archaerhodopsin-based voltage indicators, QuasAr1 and QuasAr2, which show improved brightness and voltage sensitivity, have microsecond response times and produce no photocurrent. We engineered a channelrhodopsin actuator, CheRiff, which shows high light sensitivity and rapid kinetics and is spectrally orthogonal to the QuasArs. A coexpression vector, Optopatch, enabled cross-talk–free genetically targeted all-optical electrophysiology. In cultured rat neurons, we combined Optopatch with patterned optical excitation to probe back-propagating action potentials (APs) in dendritic spines, synaptic transmission, subcellular microsecond-timescale details of AP propagation, and simultaneous firing of many neurons in a network. Optopatch measurements revealed homeostatic tuning of intrinsic excitability in human stem cell–derived neurons. In rat brain slices, Optopatch induced and reported APs and subthreshold events with high signal-to-noise ratios. The Optopatch platform enables high-throughput, spatially resolved electrophysiology without the use of conventional electrodes

Ecological implications of a flower size/number trade-off in tropical forest trees

Peer reviewedPublisher PD

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives