Sampling Setup Research Articles

Analysis of Allergenic Pollen by FTIR Microspectroscopy.

Fourier transform infrared (FTIR) spectroscopy is a powerful tool for the identification and characterization of pollen and spores. However, interpretation and multivariate analysis of infrared microscopy spectra of single pollen grains are hampered by Mie-type scattering. In this paper, we introduce a novel sampling setup for infrared microspectroscopy of pollens preventing strong Mie-type scattering. Pollen samples were embedded in a soft paraffin layer between two sheets of polyethylene foils without any further sample pretreatment. Single-grain infrared spectra of 13 different pollen samples, belonging to 11 species, were obtained and analyzed by the new approach and classified by sparse partial least-squares regression (PLSR). For the classification, chemical and physical information were separated by extended multiplicative signal correction and used together to build a classification model. A training set of 260 spectra and an independent test set of 130 spectra were used. Robust sparse classification models allowing the biochemical interpretation of the classification were obtained by the sparse PLSR, because only a subset of variables was retained for the analysis. With accuracy values of 95% and 98%, for the independent test set and full cross-validation respectively, the method is outperforming the previously published studies on development of an automated pollen analysis. Since the method is compatible with standard air-samplers, it can be employed with minimal modification in regular aerobiology studies. When compared with optical microscopy, which is the benchmark method in pollen analysis, the infrared microspectroscopy method offers better taxonomic resolution, as well as faster, more economical, and bias-free measurement.

Advancing FIB assisted 3D EBSD using a static sample setup

A new setup for automatic 3D EBSD data collection in static mode has been developed using a conventional FIB–SEM system. This setup requires no stage or sample movements between the FIB milling and EBSD mapping. Its capabilities were tested experimentally on a coherent twin boundary of an INCONEL sample. Our result demonstrates that this static setup holds many advantages in terms of data throughput and quality as compared with other ones requiring stage/sample movements. The most important advantages are the better slice alignment and an improved orientation precision in 3D space, both being prerequisite for a reliable grain boundary characterization.

Imaging fluorescence (cross-) correlation spectroscopy in live cells and organisms.

Single-plane illumination (SPIM) or total internal reflection fluorescence (TIRF) microscopes can be combined with fast and single-molecule-sensitive cameras to allow spatially resolved fluorescence (cross-) correlation spectroscopy (FCS or FCCS, hereafter referred to FCS/FCCS). This creates a powerful quantitative bioimaging tool that can generate spatially resolved mobility and interaction maps with hundreds to thousands of pixels per sample. These massively parallel imaging schemes also cause less photodamage than conventional single-point confocal microscopy-based FCS/FCCS. Here we provide guidelines for imaging FCS/FCCS measurements on commercial and custom-built microscopes (including sample preparation, setup calibration, data acquisition and evaluation), as well as anticipated results for a variety of in vitro and in vivo samples. For a skilled user of an available SPIM or TIRF setup, sample preparation, microscope alignment, data acquisition and data fitting, as described in this protocol, will take ∼1 d, depending on the sample and the mode of imaging.

Linear Dichroism Detection and Analysis in Terahertz Spectral Range

Two simple experimental techniques of quantitative linear dichroism analysis were developed with Jones calculus for polarization-sensitive terahertz time-domain spectroscopy. Both of them involve the optical measurements at only three angles of rotation for sample or polarizer setup. Such non-destructive evaluation techniques could be a useful addition for quality control of polymer or composite materials. As an example, the production-induced linear dichroism in polytetrafluoroethylene was detected, analyzed, and interpreted as a result of the well-aligned macromolecular arrangement within optical volume probed by terahertz beam.

Optimization of 3D EBSD in a FIB-SEM System Using a Static Sample Setup

Optimization of 3D EBSD in a FIB-SEM System Using a Static Sample Setup

이중화된 패턴을 참조하는 평면 변위 측정 방법

Abstract Two-dimensional displacements are obtained from the sandwiched patterns, which superpose two linearly-periodic patterns orthogonally, respectively. The transparent top pattern is identified by deflection of the laserbeam due to a difference of refractivity and the opaque bottom pattern is identified by deviation of the beam intensitydue to a difference of reflectance. In the sample setup, the top pattern made up of build-up film is manufactured byUV laser machining and the bottom pattern is manufactured by ultra-precision trench machining and deposition foraluminum plate. The proposed decoding method is verified experimentally using the 10μm equally spaced sample patterns and the devised optical system. The Korea Academia-Industrial cooperation Society. Keywords : Reflectance, Refractive index, Superposed patterns, Surface encoder 본 논문은 2013년도 정부(교육부)의 재원으로 한국연구재단의 기초연구사업 지원을 받아 수행된 것임 (NRF-2013R1A1A4A01005675). * Corresponding Author : Kwang Suk Jung(Korea National University of Transportation) Tel: +82-43-841-5135 email: ksjung@ut.ac.kr Received April 6, 2015 Revised June 10, 2015Accepted July 16, 2015 Published July 31, 2015

Optimization of Tensile Strength Measurements on Glass-Ceramic Sealant Used for SOFC Stacks

Glass-ceramic sealants are commonly used as joining materials for planar Solid Oxide Fuel Cell (SOFC) stacks. Several requirements need to be fulfilled by these materials: besides electrical insulation and adequate thermal expansion, a good adhesion on the ceramic and metallic components of a SOFC stack is necessary to form a gas-tight joint [1]. A key requirement is the mechanical strength of the sealant to maintain the integrity of the stacks under operation conditions [2]. Due to the lack of standardized methods, tensile tests were developed in-house. Preliminary measurements achieved reproducible results with extremely low tensile strength values for circular butt joints made of the iron-chromium alloy Crofer22APU and a composite sealant based on a glass matrix of the system of BaO-CaO-SiO2 reinforced with yttria-stabilized zirconia fibers [3, 4]. These results have been used for a qualitative ranking of different sealant materials. The goal of our recent studies is to improve the characterization methods of mechanical strength in order to obtain quantitative results and to achieve the understanding needed to design more robust SOFC stacks. For this purpose, computer simulations using finite element analyses (FEA) have been performed. By modelling different joint configurations, it was possible to homogenize the stress distribution along the sealing layer and to optimize the geometries of the components. It was shown that bending of the metallic components as well as residual thermal stresses had a strong effect on the initial sample setup with thin cylinders. An optimized design for the tensile components allows a more uniform distribution of tensile stresses within the sample. Different joining conditions were investigated and the calculations were verified by experiments. Scanning electron microscopic analyses were carried out on cross sections and broken samples, which allow to evaluate the microstructure of the composite and its interfacial reactions. The mechanical strength values obtained by the improved characterization method represent a tenfold increase compared to the values published in [3]. [1] Gross et al., Fuel Cell Bulletin 9 (2006) 12-15 [2] Blum et al., J. Pow. Sources 196 (2011) 7175-7181 [3] Gross et al., J. Pow. Sources 196 (2011) 7338-7342 [4] Cela Greven et al., Fuel Cells 13, No.4 (2013) 565-57

Predictability of stemflow in a species‐rich tropical forest

AbstractNumerous studies investigated the influence of abiotic (meteorological conditions) and biotic factors (tree characteristics) on stemflow generation. Although these studies identified the variables that influence stemflow volumes in simply structured forests, the combination of tree characteristics that allows a robust prediction of stemflow volumes in species‐rich forests is not well known. Many hydrological applications, however, require at least a rough estimate of stemflow volumes based on the characteristics of a forest stand. The need for robust predictions of stemflow motivated us to investigate the relationships between tree characteristics and stemflow volumes in a species‐rich tropical forest located in central Panama. Based on a sampling setup consisting of ten rainfall collectors, 300 throughfall samplers and 60 stemflow collectors and cumulated data comprising 26 rain events, we derive three main findings. Firstly, stemflow represents a minor hydrological component in the studied 1‐ha forest patch (1.0% of cumulated rainfall). Secondly, in the studied species‐rich forest, single tree characteristics are only weakly related to stemflow volumes. The influence of multiple tree parameters (e.g. crown diameter, presence of large epiphytes and inclination of branches) and the dependencies among these parameters require a multivariate approach to understand the generation of stemflow. Thirdly, predicting stemflow in species‐rich forests based on tree parameters is a difficult task. Although our best model can capture the variation in stemflow to some degree, a critical validation reveals that the model cannot provide robust predictions of stemflow. A reanalysis of data from previous studies in species‐rich forests corroborates this finding. Based on these results and considering that for most hydrological applications, stemflow is only one parameter among others to estimate, we advocate using the base model, i.e. the mean of the stemflow data, to quantify stemflow volumes for a given study area. Studies in species‐rich forests that wish to obtain predictions of stemflow based on tree parameters probably need to conduct a much more extensive sampling than currently implemented by most studies. Copyright © 2015 John Wiley & Sons, Ltd.

Multiple sample setup for testing the hydrothermal stability of adsorbents in thermal energy storage applications

Thermal energy storage based on adsorption and desorption of water on an adsorbent can achieve high energy storage densities. Many adsorbents lose adsorption capacity when operated under unfavourable hydrothermal conditions during adsorption and desorption. The stability of an adsorbent against stressing hydrothermal conditions is a key issue for its usability in adsorption thermal energy storage. We built an experimental setup that simultaneously controls the hydrothermal conditions of 16 samples arranged in a matrix of four temperatures and four water vapour pressures. This setup allows the testing of potential adsorbents between temperatures of 50 °C and 350 °C and water vapour pressures of up to 32 kPa. A measurement procedure that allows the detection of the hydrothermal stability of an adsorbent after defined time spans has been designed. We verified the functionality of the multiple sample measurements with a microporous adsorbent, a zeolite NaMSX. The hydrothermal stability of this zeolite is tested by water uptake measurements. A standard deviation lower than 1% of the 16 samples for detecting the hydrothermal stability enables setting different conditions in each sample cell. Further, we compared the water uptake measurements by measuring their adsorption isotherms with the volumetric device BELSORP Aqua 3 from Bel Japan.

Small-Scale Multiaxial Setup for Damage Detection Into the Very High Cycle Fatigue Regime

Micro electro mechanical systems, coatings, and thin films contain materials that are often subjected to complex loading conditions and high frequencies. Therefore, the implementation of a resonant multiaxial fatigue setup for small-scale samples is of high interest. Finite Element simulations have been used to design small-scale samples which possess very close bending and torsional resonant frequencies. The bending and torsional modes are excited by two piezo actuators working either in or out of phase with one another. The bending and torsional amplitudes are measured independently by a laser and the actuator amplitudes are controlled by a Field Programmable Gate Array. The fatigue setup can be used with a varying range of sample sizes from centimeters down to tens of micrometers. The novel multiaxial resonant micro fatigue setup as well as results (fatigue damage for Ni and lifetime for Cu) from bending small-scale fatigue tests are shown and discussed.

Design of a Proton-induced Quasimonochromatic Micro-XRF Setup for Wet Biological Samples

Abstract We designed and constructed a proton-induced quasimonochromatic micro-XRF system for wet biological samples. A horizontal beam of MeV protons delivered by a 1.6 MV tandem accelerator was bent downward by 45° using a dipole magnet. A copper (Cu) foil target was placed perpendicular to the incident proton beam. The thickness of the foil was 30 μm, which is slightly larger the proton range. This Cu foil was used also as a vacuum window for the X-rays. The proton-induced quasimonochromatic X-rays (QMXRs) emitted to the atmosphere through the foil were focused by a polycapillary X-ray half lens. The monochromaticity and intensity of the QMXR microbeam as a function of the incident proton energy were investigated. The QMXR microbeam impinged on the horizontal sample surface with an incident angle of 45°, and emitted fluorescent X-rays from the sample were collected by a Si-PIN X-ray detector positioned at 90° with respect to the incident microbeam. The size of the X-ray beam was 250 μm × 350 μm. To demonstrate the capability of the micro-XRF setup for in-vivo measurement of trace elements in biological samples, we measured cobalt (Co) accumulated in leaves of duckweed floating on a Co solution surface. By using standard samples which simulated the duckweed leaf, the Co concentration in the leaf in the order of 100 ppm could be quantitatively determined.

Optical rogue waves in integrable turbulence.

We report optical experiments allowing us to investigate integrable turbulence in the focusing regime of the one-dimensional nonlinear Schrödinger equation (1D NLSE). In analogy with broad spectrum excitation of a one-dimensional water tank, we launch random initial waves in a single mode optical fiber. Using an original optical sampling setup, we measure precisely the probability density function of optical power of the partially coherent waves rapidly fluctuating with time. The probability density function is found to evolve from the normal law to a strong heavy-tailed distribution, thus revealing the formation of rogue waves in integrable turbulence. Numerical simulations of 1D NLSE with stochastic initial conditions quantitatively reproduce the experiments. Our numerical investigations suggest that the statistical features experimentally observed rely on the stochastic generation of coherent analytic solutions of 1D NLSE.

Characterizing morphology in organic systems with resonant soft X-ray scattering

Resonant soft X-ray scattering (R-SoXS) has proven to be a highly useful technique for studying the morphology of soft matter thin films due to the large intrinsic contrast between organic materials and the anisotropic nature of the resonant electronic state transitions from which the contrast originates. This allows R-SoXS users to measure spatial composition correlations from crystalline and amorphous phases in heterogeneous organic samples, infer relative domain purity, and determine average local molecular ordering correlations. R-SoXS has been used to study the morphology of organic photovoltaics, organic thin film transistors, biological systems, and block copolymer engineering applications. The mesoscopic morphological information compliments molecular packing information determined with hard X-rays, so that complex structure–property relationships can be elucidated over a large range of length scales. Extensions of R-SoXS have also emerged that make use of more advanced sample setups or different experimental geometries than normal transmission, such as θ–2θ reflectivity or grazing incidence.

ASPIRE: An automated sample positioning and irradiation system for radiation biology experiments at Inter University Accelerator Centre, New Delhi

An automated irradiation setup for biology samples has been built at Inter University Accelerator Centre (IUAC), New Delhi, India. It can automatically load and unload 20 biology samples in a run of experiment. It takes about 20 min [2% of the cell doubling time] to irradiate all the 20 samples. Cell doubling time is the time taken by the cells (kept in the medium) to grow double in numbers. The cells in the samples keep growing during entire of the experiment. The fluence irradiated to the samples is measured with two silicon surface barrier detectors. Tests show that the uniformity of fluence and dose of heavy ions reaches to 2% at the sample area in diameter of 40 mm. The accuracy of mean fluence at the center of the target area is within 1%. The irradiation setup can be used to the studies of radiation therapy, radiation dosimetry and molecular biology at the heavy ion accelerator.

Novel Set-Up for Low-Disturbance Sampling of Volatile and Non-volatile Compounds from Plant Roots

Most studies on rhizosphere chemicals are carried out in substrate-free set-ups or in artificial substrates using sampling methods that require an air flow and may thus cause disturbance to the rhizosphere. Our study aimed to develop a simplified and inexpensive system that allows analysis of rhizosphere chemicals at experimentally less disturbed conditions. We designed a mesocosm in which volatile rhizosphere chemicals were sampled passively (by diffusion) without air- and water flow on polydimethylsiloxane-(PDMS) tubes. Dandelion (Taraxacum sect. ruderalia) was used as model plant; roots were left undamaged. Fifteen volatiles were retrieved from the sorptive material by thermal desorption for analysis by gas chromatography/mass spectrometry (GC/MS). Furthermore, three sugars were collected from the rhizosphere substrate by aqueous extraction and derivatized prior to GC/MS analysis. In order to study how the quantity of detected rhizosphere compounds depends on the type of soil or substrate, we determined the matrix-dependent recovery of synthetic rhizosphere chemicals. Furthermore, we compared sorption of volatiles on PDMS tubes with and without direct contact to the substrate. The results show that the newly designed mesocosm is suitable for low-invasive extraction of volatile and non-volatile compounds from rhizospheres. We further highlight how strongly the type of substrate and contact of PDMS tubes to the substrate affect the detectability of compounds from rhizospheres.

Facile Fabrication of SERS-based Microchannel Device for Hazardous Chemical Analysis†

Surface-enhanced Raman scattering( SERS)-based microchannel device was fabricated by selfassembling silver colloids. The detection limits of the device for rhodamine 6G( R6G) and 4-mercaptopyridine( 4-MPY) were as low as 10- 11 and 10- 8mol / L,respectively,therefore,the device is a very efficient SERSactive substrate. Furthermore,two hazardous chemicals,Thiram and Melamine,were detected by the microchannel device. The detection limits for Melamine and Thiram were 10- 6and 10- 7mol / L,respectively. The results show that the microchannel device can be used to analyze these two harmful chemicals. It can be used as a miniature SERS sampling setup to detect trace amount of chemicals and for on-line or in-situ detection,and have the potential for the microanalysis of liquid chemicals.

Recreating Crumley: The setup (Updated)

Hi! I’m setting up the Crumley Experiment now that I have most of what I need. I ordered some more tobacco seeds but I have no idea when those are set to arrive so I’ll begin a preliminary experiment with what I have to work out the kinks. If you are too lazy to click the link above then I’ll recall for you that the experiment involved putting tobacco seeds in different percentages of D2O and tracking seed germination. Their setup was to put seeds in petri dishes on moist cloth. I found these slide/petri dish hybrids called Analyslide that seemed perfectly suited to this and I’m going to omit the moist cloth and instead just fully submerge the seeds. The volume of the dish portion seems pretty low (less than 5mL is my guess) and the lids create a nice seal which will hopefully keep deuterium exchange to a minimum. I built a photography system for the dishes which works a little like an inverted microscope. The slides sit up high on some cage system rods (from Thor Labs) and the camera is mounted on a rail below aimed upward. Currently I have to use a mirror to see in the eyepiece, but I’m thinking of equipping a webcam under the camera so I can see precisely what I’m looking at. You can see the setup below with some dummy slides and some test images. I wanted to see how easy it would be to focus on something in the Analyslide so I wrote “HI!” on a piece of paper and taped it inside. It worked pretty well. Test image at farthest zoom Test image at closest zoom sample and image acquistion setup Another view of the setup Barnstead EasyPure RoDI Update: I forgot to mention where the water comes from! It is very easy to overlook that fact since water is the most used chemical in the lab. When Koch talks about setting up osmotic pressure experiments he always mentions that water is the most overlooked variable because it is everywhere and we take it’s effect on the experimental world for granted. Anyways: All water is purchased from Sigma-Aldrich, except DI water which comes from a Thermo purifier in the lab. I purchased D2O in a 100g amount bottle product number 151882. Deuterium depleted water (DDW) is also purchased in 100g amounts and has the product number 195294. The DI water comes from a Barnstead EasyPure RoDI filtration system from Thermo Scientific, with part number D13321. I took a picture of ours for your viewing pleasure below. Barnstead EasyPure RoDI

Finite sample behavior of a sieve profile estimator in the single index model

We apply the results of Andresen et. al. (2014) on finite sample properties of sieve M-estimators and Andresen et. al. (2015) on the convergence of an alternating maximization procedure to analyse a sieve profile maximization estimator in the single index model with linear index function. The link function is approximated with $C^{3}$-Daubechies-wavelets with compact support. We derive results like Wilks phenomenon and Fisher Theorem in a finite sample setup even when the model is miss-specified. Furthermore we show that an alternating maximization procedure converges to the global maximizer and we assess the performance of Friedman’s projection pursuit procedure. The approach is based on showing that the conditions of Andresen et. al. (2014) and (2015) can be satisfied under a set of mild regularity and moment conditions on the link function, the regressors and the additive noise. The results allow to construct non-asymptotic confidence sets and to derive asymptotic bounds for the estimator as corollaries.

Bench Test for the Detection of Bacterial Contamination in Platelet Concentrates Using Rapid and Cultural Detection Methods with a Standardized Proficiency Panel

Background: The most frequent infectious complication in transfusion therapy in developed countries is related to the bacterial contamination of platelet concentrates (PCs). Rapid and cultural screening methods for bacterial detection in platelets are available, but external performance evaluation, especially of rapid methods, has been difficult to realize so far. Here we summarize the results of three individual collaborative trials using an external quality assessment program (EQAP) for the application of current rapid and cultural screening methods. Methods: Three different modules were available for the detection of bacterial contamination: module 1: rapid methods, module 2: culture methods, module 3: bacterial identification methods. The sample set-up included up to six different bacterial strains, 1-2 negative samples and 4-6 positive samples with stabilized bacterial cell counts (approximately 10³/10⁴/10⁵ CFU/ml). Time schedule for testing was limited (module 1: 6 h, module 2 and 3: 7 days). Results: Samples of module 1 were analyzed with two different rapid methods (BactiFlow, NAT). The results of the three individual collaborative trials showed that all participants detected the negative samples with both assays correctly. Samples spiked with 10⁴ to 10⁵ CFU/ml of bacteria obtained positive results with both rapid screening methods, whereas samples spiked with only 10³ CFU/ml disclosed a lower number of correctly identified positive results by NAT (86.6-93.8% sensitivity) compared to BactiFlow (100% sensitivity). The results for modules 2 and 3 revealed a 100% diagnostic sensitivity and specificity in all three collaborative trials. Conclusion: This proficiency panel facilitates the verification of the analytical sensitivity of rapid and cultural bacterial detection systems under controlled routine conditions. The concept of samples provided in this EQAP has three main advantages: i) samples can be examined by both rapid and culture methods, ii) the provided material is matrix-equivalent, and iii) the sample material is ready-to-use.

Studying the surface layers of products using a low-vacuum scanning electron microscope

The results of studying parameters of the surface layer after the tribological testing of different materials using a low-vacuum Phenom ProX scanning electron microscope are presented. It is shown that its use for the analysis of surface layers provides a very accurate estimate of their main parameters, i.e., volume topography and chemical composition for an insignificant (several seconds) sample setup time. The results of analysis of worn surfaces of FeGr1Cu19Sn0.9(MoS2)0.5 powder steels obtained by sintering and infiltration of a copper alloy, oxidized aluminum alloy AlCu4MgSi, and Vitalium Co-Cr-Mo alloy used for dental prostheses are presented as examples.