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Ultrasound (US) image guidance is widely used for minimally invasive procedures, but the invasive medical devices (such as metallic needles), especially their tips, can be poorly visualised in US images, leading to significant complications. Photoacoustic (PA) imaging is promising for visualising invasive devices and peripheral tissue targets. Light-emitting diodes (LEDs) acting as PA excitation sources facilitate the clinical translation of PA imaging, but the image quality is degraded due to the low pulse energy leading to insufficient contrast with needles at deep locations. In this paper, photoacoustic visualisation of clinical needles was enhanced by elastomeric nanocomposite coatings with superficial and interstitial illumination. Candle soot nanoparticle-polydimethylsiloxane (CSNP-PDMS) composites with high optical absorption and large thermal expansion coefficients were applied onto the needle exterior and the end-face of an optical fibre placed in the needle lumen. The excitation light was delivered at the surface by LED arrays and through the embedded optical fibre by a pulsed diode laser to improve the visibility of the needle tip. The performance was validated using an ex-vivo tissue model. An LED-based PA/US imaging system was used for imaging the needle out-of-plane and in-plane insertions over approach angles of 20 deg to 55 deg. The CSNP-PDMS composite conferred substantial visual enhancements on both the needle shaft and the tip, with an average of 1.7- and 1.6-fold improvements in signal-to-noise ratios (SNRs), respectively. With the extended light field involving extracorporeal and interstitial illumination and the highly absorbing coatings, enhanced visualisation of the needle shaft and needle tip was achieved with PA imaging, which could be helpful in current US-guided minimally invasive surgeries. ispartof: SENSORS vol:22 issue:17 ispartof: location:Switzerland status: published

International audience; Background Metabolomics is the comprehensive study of a multitude of small molecules to gain insight into an organism's metabolism. The research field is dynamic and expanding with applications across biomedical, biotechnological, and many other applied biological domains. Its computationally intensive nature has driven requirements for open data formats, data repositories, and data analysis tools. However, the rapid progress has resulted in a mosaic of independent, and sometimes incompatible, analysis methods that are difficult to connect into a useful and complete data analysis solution. Findings PhenoMeNal (Phenome and Metabolome aNalysis) is an advanced and complete solution to set up Infrastructure-as-a-Service (IaaS) that brings workflow-oriented, interoperable metabolomics data analysis platforms into the cloud. PhenoMeNal seamlessly integrates a wide array of existing open-source tools that are tested and packaged as Docker containers through the project's continuous integration process and deployed based on a kubernetes orchestration framework. It also provides a number of standardized, automated, and published analysis workflows in the user interfaces Galaxy, Jupyter, Luigi, and Pachyderm. Conclusions PhenoMeNal constitutes a keystone solution in cloud e-infrastructures available for metabolomics. PhenoMeNal is a unique and complete solution for setting up cloud e-infrastructures through easy-to-use web interfaces that can be scaled to any custom public and private cloud environment. By harmonizing and automating software installation and configuration and through ready-to-use scientific workflow user interfaces, PhenoMeNal has succeeded in providing scientists with workflow-driven, reproducible, and shareable metabolomics data analysis platforms that are interfaced through standard data formats, representative datasets, versioned, and have been tested for reproducibility and interoperability. The elastic implementation of PhenoMeNal further allows easy adaptation of the infrastructure to other application areas and omics research domains.

Suitable instrumentation for laser-accelerated proton (ion) beams is critical for development of integrated, laser-driven ion accelerator systems. Instrumentation aimed at beam diagnostics and control must be applied to the driving laser pulse, the laser-plasma that forms at the target and the emergent proton (ion) bunch in a correlated way to develop these novel accelerators. This report is a brief overview of established diagnostic techniques and new developments based on material presented at the first workshop on 'Instrumentation for Diagnostics and Control of Laser-accelerated Proton (Ion) Beams' in Abingdon, UK. It includes radiochromic film (RCF), image plates (IP), micro-channel plates (MCP), Thomson spectrometers, prompt inline scintillators, time and space-resolved interferometry (TASRI) and nuclear activation schemes. Repetition-rated instrumentation requirements for target metrology are also addressed. (C) 2013 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

International audience; The complete determination of all rate and equilibrium constants of the network of reversible chemical reactions involving the anthocyanin analogue, 3′,4′-dihydroxy-7-O-β-D-glucopyranosyloxyflavylium chloride, was achieved by means of UV-visible spectroscopy, flash photolysis and pH jumps monitored by stopped-flow. An energy level diagram containing all the data was obtained. A detailed step by step procedure illustrating all the calculations is reported.

The characterization of pharmacokinetic and biodistribution profiles is an essential step in the development process of new candidate drugs or imaging agents. Simultaneously, the assessment of organ function related to the uptake and clearance of drugs is of great importance. To this end, we demonstrate an imaging platform capable of high-rate characterization of the dynamics of fluorescent agents in multiple organs using multispectral optoacoustic tomography (MSOT). A spatial resolution of approximately 150 µm through mouse cross-sections allowed us to image blood vessels, the kidneys, the liver and the gall bladder. In particular, MSOT was employed to characterize the removal of indocyanine green from the systemic circulation and its time-resolved uptake in the liver and gallbladder. Furthermore, it was possible to track the uptake of a carboxylate dye in separate regions of the kidneys. The results demonstrate the acquisition of agent concentration metrics at rates of 10 samples per second at a single wavelength and 17 s per multispectral sample with 10 signal averages at each of 5 wavelengths. Overall, such imaging performance introduces previously undocumented capabilities of fast, high resolution in vivo imaging of the fate of optical agents for drug discovery and basic biological research.

At Sixes and Sevens Molecular synthesis and macroscopic aggregation have often been regarded as entirely separate processes. From the researcher's standpoint, once reagents have been mixed, synthesis is largely passive, whereas processes such as crystallization can be more actively manipulated. Carnall et al. (p. 1502 ) characterized an unusual system in which the formation of aggregated cyclic macromolecules (macrocycles) from small peptide-based building blocks was governed by intimately interdependent factors ranging from the scale of covalent bond formation all the way to micron scale fiber growth. As the macrocycles stacked against one another to form the fibers, they remained loosely bonded enough internally to incorporate or expel individual building blocks. Varying the type of mechanical force applied to the growing fibers (either through shaking or stirring the solution), alternately favored formation of either 6-membered or 7-membered covalent macrocycles.

We describe an experimental setup based on a sealed parallel-plate avalanche counter, which allows conversion electron Mossbauer spectroscopy at temperatures down to 120 K. A study of the counting gas performances is carried out in order to find out the appropriate operating conditions. The detector can work in a wide range of pressures and voltages at room and low temperatures, for both iron- and tin-based Mossbauer transitions. An estimation of the gas gain is obtained by using a simple approach, which considers the avalanche gas process in parallel-plate geometry. The gas gain as a function of the filling pressure shows a maximum at room temperature and a monotonic increase at low temperature. The experimental setup has been tested with the determination of the Debye temperature of beta-Sn, SnO2, and epsilon-FeSi. (c) 2007 American Institute of Physics.

International audience; The low but known risk of bacterial contamination has emerged as the greatest residual threat of transfusion-transmitted diseases. Label-free detection of a bacterial model, Escherichia coli, is performed using nonfaradic electrochemical impedance spectroscopy (EIS). Biotinylated polyclonal anti-E. coli is linked to a mixed self-assembled monolayer (SAM) on a gold electrode through a strong biotin-neutravidin interaction. The binding of one antibody molecule for 3.6 neutravidin molecules is determined using the surface plasmon resonance (SPR). The detection limit of E. coli found by SPR is 10(7) cfu/mL. After modeling the impedance Nyquist plot of E. coli/anti-E. coli/mixed SAM/gold electrode for increasing concentrations of E. coli (whole bacteria or lysed bacteria), the main parameter that is modified is the polarization resistance R-P. A sigmoid variation of R-P is observed when the log concentration of bacteria (whole or lysed) increases. A concentration of 10 cfu/mL whole bacteria is detected by EIS measurements while 10(3) cfu/mL is detected for lysed E. coli.

The study of intracellular communication requires devices that can not only monitor the bioelectric activity, but also control and observe the biochemical environment at the cellular level. This paper reports on the development and characterisation of implantable polyimide microprobes that allow simultaneous, selective chemical delivery/probing and multi-channel recording/stimulation of bioelectric activity. The key component of the system is a flexible polyimide substrate with embedded microchannels that is batch-fabricated combining polyimide micromachining and a lamination technique. The devices provide platinum microelectrodes on both sides of the polyimide substrate with an active surface between 20 mum x 20 mum and 50 mum x 50 mum. The embedded microchannels permit highly localised drug delivery or probing at the tip of the device via channel outlets adjacent to the microelectrodes. The microelectrodes were characterised by electrical impedance spectroscopy and the microchannels were studied in microflow experiments. Two different fluid delivery schemes were explored in two different designs. The first device type consists of a simple combination of microchannels and microelectrodes on one substrate. Liquids are ejected at the tip of the device by pressure injection techniques. The second device was inspired by the so-called U-tube concept allowing for highly localised delivery of controlled amounts of liquids in the picoliters range. Thus, the influence of chemical compounds on the electrical activity of cells can be studied with high temporal and spatial resolution. The flexible, implantable devices can be used for studying the chemical and electrical information exchange and communication of cells in in vivo and in vitro experiments. (C) 2003 Elsevier B.V. All rights reserved.

A new cytological tool, based on the microCoulter particle counter (microCPC) principle, aimed at diagnostic applications for cell counting and separation in haematology, oncology or toxicology is described. The device measures the spectral impedance of individual cells or particles and allows screening rates over 100 samples s(-1) on a single-cell basis. This analyzer is intended to drive a sorting actuator producing a subsequent cell separation. Size reduction and integration of functions are essential in achieving precise measurements and high throughput. 3D finite element simulations are presented to compare various electrode geometries and their influence on cell parameters estimation. The device is based on a glass-polyimide microfluidic chip with integrated channels and electrodes microfabricated at the length scale of the particles to be investigated (1-20 microm). A laminar liquid flow carries the suspended particles through the measurement area. Each particle's impedance signal is recorded by a differential pair of microelectrodes using the cell surrounding media as a reference. The micromachined chip and processing electronic circuit allow simultaneous impedance measurements at multiple frequencies, ranging from 100 kHz to 15 MHz. In this paper, we describe the microfabrication and characterisation of an on-chip flow-cytometer as the first building block of a complete cell-sorting device. We then discuss the signal conditioning technique and finally impedance measurements of cells and particles of different sizes and types to demonstrate the differentiation of subpopulations in a mixed sample.