Sample records for additional sample preparation

  1. Preparation of bone samples in the Gliwice Radiocarbon Laboratory for AMS radiocarbon dating.

    PubMed

    Piotrowska, N; Goslar, T

    2002-12-01

    In the Gliwice Radiocarbon Laboratory, a system for preparation of samples for AMS dating has been built. At first it was used to produce graphite targets from plant macrofossils and sediments. In this study we extended its capabilities with the preparation of bones. We dealt with 3 methods; the first was the classical Longin method of collagen extraction, the second one included additional treatment of powdered bone in alkali solution, while in the third one carboxyl carbon was separated from amino acids obtained after hydrolysis of protein. The suitability of the methods was tested on 2 bone samples. Most of our samples gave ages > 40 kyr BP, suggesting good performance of the adapted methods, except for one sample prepared with simple Longin method. For routine preparation of bones we chose the Longin method with additional alkali treatment.

  2. Sampling hazelnuts for aflatoxin: uncertainty associated with sampling, sample preparation, and analysis.

    PubMed

    Ozay, Guner; Seyhan, Ferda; Yilmaz, Aysun; Whitaker, Thomas B; Slate, Andrew B; Giesbrecht, Francis

    2006-01-01

    The variability associated with the aflatoxin test procedure used to estimate aflatoxin levels in bulk shipments of hazelnuts was investigated. Sixteen 10 kg samples of shelled hazelnuts were taken from each of 20 lots that were suspected of aflatoxin contamination. The total variance associated with testing shelled hazelnuts was estimated and partitioned into sampling, sample preparation, and analytical variance components. Each variance component increased as aflatoxin concentration (either B1 or total) increased. With the use of regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation, and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific aflatoxin concentration. The sampling, sample preparation, and analytical variances associated with estimating aflatoxin in a hazelnut lot at a total aflatoxin level of 10 ng/g and using a 10 kg sample, a 50 g subsample, dry comminution with a Robot Coupe mill, and a high-performance liquid chromatographic analytical method are 174.40, 0.74, and 0.27, respectively. The sampling, sample preparation, and analytical steps of the aflatoxin test procedure accounted for 99.4, 0.4, and 0.2% of the total variability, respectively.

  3. Synchrotron/crystal sample preparation

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1993-01-01

    The Center for Applied Optics (CAO) of the University of Alabama in Huntsville (UAH) prepared this final report entitled 'Synchrotron/Crystal Sample Preparation' in completion of contract NAS8-38609, Delivery Order No. 53. Hughes Danbury Optical Systems (HDOS) is manufacturing the Advanced X-ray Astrophysics Facility (AXAF) mirrors. These thin-walled, grazing incidence, Wolter Type-1 mirrors, varying in diameter from 1.2 to 0.68 meters, must be ground and polished using state-of-the-art techniques in order to prevent undue stress due to damage or the presence of crystals and inclusions. The effect of crystals on the polishing and grinding process must also be understood. This involves coating special samples of Zerodur and measuring the reflectivity of the coatings in a synchrotron system. In order to gain the understanding needed on the effect of the Zerodur crystals by the grinding and polishing process, UAH prepared glass samples by cutting, grinding, etching, and polishing as required to meet specifications for witness bars for synchrotron measurements and for investigations of crystals embedded in Zerodur. UAH then characterized these samples for subsurface damage and surface roughness and figure.

  4. [Sample preparation and bioanalysis in mass spectrometry].

    PubMed

    Bourgogne, Emmanuel; Wagner, Michel

    2015-01-01

    The quantitative analysis of compounds of clinical interest of low molecular weight (<1000 Da) in biological fluids is currently in most cases performed by liquid chromatography-mass spectrometry (LC-MS). Analysis of these compounds in biological fluids (plasma, urine, saliva, hair...) is a difficult task requiring a sample preparation. Sample preparation is a crucial part of chemical/biological analysis and in a sense is considered the bottleneck of the whole analytical process. The main objectives of sample preparation are the removal of potential interferences, analyte preconcentration, and converting (if needed) the analyte into a more suitable form for detection or separation. Without chromatographic separation, endogenous compounds, co-eluted products may affect a quantitative method in mass spectrometry performance. This work focuses on three distinct parts. First, quantitative bioanalysis will be defined, different matrices and sample preparation techniques currently used in bioanalysis by mass spectrometry of/for small molecules of clinical interest in biological fluids. In a second step the goals of sample preparation will be described. Finally, in a third step, sample preparation strategies will be made either directly ("dilute and shoot") or after precipitation.

  5. Microfluidic Sample Preparation for Diagnostic Cytopathology

    PubMed Central

    Mach, Albert J.; Adeyiga, Oladunni B.; Di Carlo, Dino

    2014-01-01

    The cellular components of body fluids are routinely analyzed to identify disease and treatment approaches. While significant focus has been placed on developing cell analysis technologies, tools to automate the preparation of cellular specimens have been more limited, especially for body fluids beyond blood. Preparation steps include separating, concentrating, and exposing cells to reagents. Sample preparation continues to be routinely performed off-chip by technicians, preventing cell-based point-of-care diagnostics, increasing the cost of tests, and reducing the consistency of the final analysis following multiple manually-performed steps. Here, we review the assortment of biofluids for which suspended cells are analyzed, along with their characteristics and diagnostic value. We present an overview of the conventional sample preparation processes for cytological diagnosis. We finally discuss the challenges and opportunities in developing microfluidic devices for the purpose of automating or miniaturizing these processes, with particular emphases on preparing large or small volume samples, working with samples of high cellularity, automating multi-step processes, and obtaining high purity subpopulations of cells. We hope to convey the importance of and help identify new research directions addressing the vast biological and clinical applications in preparing and analyzing the array of available biological fluids. Successfully addressing the challenges described in this review can lead to inexpensive systems to improve diagnostic accuracy while simultaneously reducing overall systemic healthcare costs. PMID:23380972

  6. Novel Sample-handling Approach for XRD Analysis with Minimal Sample Preparation

    NASA Technical Reports Server (NTRS)

    Sarrazin, P.; Chipera, S.; Bish, D.; Blake, D.; Feldman, S.; Vaniman, D.; Bryson, C.

    2004-01-01

    Sample preparation and sample handling are among the most critical operations associated with X-ray diffraction (XRD) analysis. These operations require attention in a laboratory environment, but they become a major constraint in the deployment of XRD instruments for robotic planetary exploration. We are developing a novel sample handling system that dramatically relaxes the constraints on sample preparation by allowing characterization of coarse-grained material that would normally be impossible to analyze with conventional powder-XRD techniques.

  7. Optimization for Peptide Sample Preparation for Urine Peptidomics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sigdel, Tara K.; Nicora, Carrie D.; Hsieh, Szu-Chuan

    2014-02-25

    Analysis of native or endogenous peptides in biofluids can provide valuable insights into disease mechanisms. Furthermore, the detected peptides may also have utility as potential biomarkers for non-invasive monitoring of human diseases. The non-invasive nature of urine collection and the abundance of peptides in the urine makes analysis by high-throughput ‘peptidomics’ methods , an attractive approach for investigating the pathogenesis of renal disease. However, urine peptidomics methodologies can be problematic with regards to difficulties associated with sample preparation. The urine matrix can provide significant background interference in making the analytical measurements that it hampers both the identification of peptides andmore » the depth of the peptidomics read when utilizing LC-MS based peptidome analysis. We report on a novel adaptation of the standard solid phase extraction (SPE) method to a modified SPE (mSPE) approach for improved peptide yield and analysis sensitivity with LC-MS based peptidomics in terms of time, cost, clogging of the LC-MS column, peptide yield, peptide quality, and number of peptides identified by each method. Expense and time requirements were comparable for both SPE and mSPE, but more interfering contaminants from the urine matrix were evident in the SPE preparations (e.g., clogging of the LC-MS columns, yellowish background coloration of prepared samples due to retained urobilin, lower peptide yields) when compared to the mSPE method. When we compared data from technical replicates of 4 runs, the mSPE method provided significantly improved efficiencies for the preparation of samples from urine (e.g., mSPE peptide identification 82% versus 18% with SPE; p = 8.92E-05). Additionally, peptide identifications, when applying the mSPE method, highlighted the biology of differential activation of urine peptidases during acute renal transplant rejection with distinct laddering of specific peptides, which was obscured for most

  8. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 761.323 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL... Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the...

  9. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 761.323 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL... Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the...

  10. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 761.323 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL... Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the...

  11. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this section...

  12. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this section...

  13. 7 CFR 27.21 - Preparation of samples of cotton.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this section...

  14. Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dunzik-Gougar, M. L.; van Rooyen, I. J.; Hill, C. M.

    Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of differentmore » material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.« less

  15. Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

    DOE PAGES

    Dunzik-Gougar, M. L.; van Rooyen, I. J.; Hill, C. M.; ...

    2016-08-25

    Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of differentmore » material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.« less

  16. Recent advances in applications of nanomaterials for sample preparation.

    PubMed

    Xu, Linnan; Qi, Xiaoyue; Li, Xianjiang; Bai, Yu; Liu, Huwei

    2016-01-01

    Sample preparation is a key step for qualitative and quantitative analysis of trace analytes in complicated matrix. Along with the rapid development of nanotechnology in material science, numerous nanomaterials have been developed with particularly useful applications in analytical chemistry. Benefitting from their high specific areas, increased surface activities, and unprecedented physical/chemical properties, the potentials of nanomaterials for rapid and efficient sample preparation have been exploited extensively. In this review, recent progress of novel nanomaterials applied in sample preparation has been summarized and discussed. Both nanoparticles and nanoporous materials are evaluated for their unusual performance in sample preparation. Various compositions and functionalizations extended the applications of nanomaterials in sample preparations, and distinct size and shape selectivity was generated from the diversified pore structures of nanoporous materials. Such great variety make nanomaterials a kind of versatile tools in sample preparation for almost all categories of analytes. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Extending the solvent-free MALDI sample preparation method.

    PubMed

    Hanton, Scott D; Parees, David M

    2005-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is an important technique to characterize many different materials, including synthetic polymers. MALDI mass spectral data can be used to determine the polymer average molecular weights, repeat units, and end groups. One of the key issues in traditional MALDI sample preparation is making good solutions of the analyte and the matrix. Solvent-free sample preparation methods have been developed to address these issues. Previous results of solvent-free or dry prepared samples show some advantages over traditional wet sample preparation methods. Although the results of the published solvent-free sample preparation methods produced excellent mass spectra, we found the method to be very time-consuming, with significant tool cleaning, which presents a significant possibility of cross contamination. To address these issues, we developed an extension of the solvent-free method that replaces the mortar and pestle grinding with ball milling the sample in a glass vial with two small steel balls. This new method generates mass spectra with equal quality of the previous methods, but has significant advantages in productivity, eliminates cross contamination, and is applicable to liquid and soft or waxy analytes.

  18. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the... PCB remediation waste at the cleanup site, or must be the same kind of material as that waste. For...

  19. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

    PubMed

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  20. An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wen, Haiming; Lin, Yaojun; Seidman, David N.

    The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

  1. An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

    DOE PAGES

    Wen, Haiming; Lin, Yaojun; Seidman, David N.; ...

    2015-09-09

    The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

  2. Modular microfluidic system for biological sample preparation

    DOEpatents

    Rose, Klint A.; Mariella, Jr., Raymond P.; Bailey, Christopher G.; Ness, Kevin Dean

    2015-09-29

    A reconfigurable modular microfluidic system for preparation of a biological sample including a series of reconfigurable modules for automated sample preparation adapted to selectively include a) a microfluidic acoustic focusing filter module, b) a dielectrophoresis bacteria filter module, c) a dielectrophoresis virus filter module, d) an isotachophoresis nucleic acid filter module, e) a lyses module, and f) an isotachophoresis-based nucleic acid filter.

  3. M3FT-17OR0301070211 - Preparation of Hot Isostatically Pressed AgZ Waste Form Samples

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jubin, Robert Thomas; Bruffey, Stephanie H.; Jordan, Jacob A.

    The production of radioactive iodine-bearing waste forms that exhibit long-term stability and are suitable for permanent geologic disposal has been the subject of substantial research interest. One potential method of iodine waste form production is hot isostatic pressing (HIP). Recent studies at Oak Ridge National Laboratory (ORNL) have investigated the conversion of iodine-loaded silver mordenite (I-AgZ) directly to a waste form by HIP. ORNL has performed HIP with a variety of sample compositions and pressing conditions. The base mineral has varied among AgZ (in pure and engineered forms), silver-exchanged faujasite, and silverexchanged zeolite A. Two iodine loading methods, occlusion andmore » chemisorption, have been explored. Additionally, the effects of variations in temperature and pressure of the process have been examined, with temperature ranges of 525°C–1,100°C and pressure ranges of 100–300 MPa. All of these samples remain available to collaborators upon request. The sample preparation detailed in this document is an extension of that work. In addition to previously prepared samples, this report documents the preparation of additional samples to support stability testing. These samples include chemisorbed I-AgZ and pure AgI. Following sample preparation, each sample was processed by HIP by American Isostatic Presses Inc. and returned to ORNL for storage. ORNL will store the samples until they are requested by collaborators for durability testing. The sample set reported here will support waste form durability testing across the national laboratories and will provide insight into the effects of varied iodine content on iodine retention by the produced waste form and on potential improvements in waste form durability provided by the zeolite matrix.« less

  4. Recent advances of mesoporous materials in sample preparation.

    PubMed

    Zhao, Liang; Qin, Hongqiang; Wu, Ren'an; Zou, Hanfa

    2012-03-09

    Sample preparation has been playing an important role in the analysis of complex samples. Mesoporous materials as the promising adsorbents have gained increasing research interest in sample preparation due to their desirable characteristics of high surface area, large pore volume, tunable mesoporous channels with well defined pore-size distribution, controllable wall composition, as well as modifiable surface properties. The aim of this paper is to review the recent advances of mesoporous materials in sample preparation with emphases on extraction of metal ions, adsorption of organic compounds, size selective enrichment of peptides/proteins, specific capture of post-translational peptides/proteins and enzymatic reactor for protein digestion. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. 40 CFR 761.323 - Sample preparation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROHIBITIONS Self-Implementing Alternative Extraction and Chemical Analysis Procedures for Non-liquid PCB Remediation Waste Samples § 761.323 Sample preparation. (a) The comparison study requires analysis of a... of use in this chemical extraction and chemical analysis comparison study, a person may adjust PCB...

  6. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Jungdae; Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749; Nam, Hyoungdo

    2015-09-15

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper andmore » stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.« less

  7. Sample Preparation for Electron Probe Microanalysis—Pushing the Limits

    PubMed Central

    Geller, Joseph D.; Engle, Paul D.

    2002-01-01

    There are two fundamental considerations in preparing samples for electron probe microanalysis (EPMA). The first one may seem obvious, but we often find it is overlooked. That is, the sample analyzed should be representative of the population from which it comes. The second is a direct result of the assumptions in the calculations used to convert x-ray intensity ratios, between the sample and standard, to concentrations. Samples originate from a wide range of sources. During their journey to being excited under the electron beam for the production of x rays there are many possibilities for sample alteration. Handling can contaminate samples by adding extraneous matter. In preparation, the various abrasives used in sizing the sample by sawing, grinding and polishing can embed themselves. The most accurate composition of a contaminated sample is, at best, not representative of the original sample; it is misleading. Our laboratory performs EPMA analysis on customer submitted samples and prepares over 250 different calibration standards including pure elements, compounds, alloys, glasses and minerals. This large variety of samples does not lend itself to mass production techniques, including automatic polishing. Our manual preparation techniques are designed individually for each sample. The use of automated preparation equipment does not lend itself to this environment, and is not included in this manuscript. The final step in quantitative electron probe microanalysis is the conversion of x-ray intensities ratios, known as the “k-ratios,” to composition (in mass fraction or atomic percent) and/or film thickness. Of the many assumptions made in the ZAF (where these letters stand for atomic number, absorption and fluorescence) corrections the localized geometry between the sample and electron beam, or takeoff angle, must be accurately known. Small angular errors can lead to significant errors in the final results. The sample preparation technique then becomes very

  8. A Combined Fabrication and Instrumentation Platform for Sample Preparation.

    PubMed

    Guckenberger, David J; Thomas, Peter C; Rothbauer, Jacob; LaVanway, Alex J; Anderson, Meghan; Gilson, Dan; Fawcett, Kevin; Berto, Tristan; Barrett, Kevin; Beebe, David J; Berry, Scott M

    2014-06-01

    While potentially powerful, access to molecular diagnostics is substantially limited in the developing world. Here we present an approach to reduced cost molecular diagnostic instrumentation that has the potential to empower developing world communities by reducing costs through streamlining the sample preparation process. In addition, this instrument is capable of producing its own consumable devices on demand, reducing reliance on assay suppliers. Furthermore, this instrument is designed with an "open" architecture, allowing users to visually observe the assay process and make modifications as necessary (as opposed to traditional "black box" systems). This open environment enables integration of microfluidic fabrication and viral RNA purification onto an easy-to-use modular system via the use of interchangeable trays. Here we employ this system to develop a protocol to fabricate microfluidic devices and then use these devices to isolate viral RNA from serum for the measurement of human immunodeficiency virus (HIV) viral load. Results obtained from this method show significantly reduced error compared with similar nonautomated sample preparation processes. © 2014 Society for Laboratory Automation and Screening.

  9. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Preparing validation study samples..., AND USE PROHIBITIONS Comparison Study for Validating a New Performance-Based Decontamination Solvent Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to...

  10. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Preparing validation study samples..., AND USE PROHIBITIONS Comparison Study for Validating a New Performance-Based Decontamination Solvent Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to...

  11. Potential artifacts associated with historical preparation of joint compound samples and reported airborne asbestos concentrations.

    PubMed

    Brorby, G P; Sheehan, P J; Berman, D W; Bogen, K T; Holm, S E

    2011-05-01

    Airborne samples collected in the 1970s for drywall workers using asbestos-containing joint compounds were likely prepared and analyzed according to National Institute of Occupational Safety and Health Method P&CAM 239, the historical precursor to current Method 7400. Experimentation with a re-created, chrysotile-containing, carbonate-based joint compound suggested that analysis following sample preparation by the historical vs. current method produces different fiber counts, likely because of an interaction between the different clearing and mounting chemicals used and the carbonate-based joint compound matrix. Differences were also observed during analysis using Method 7402, depending on whether acetic acid/dimethylformamide or acetone was used during preparation to collapse the filter. Specifically, air samples of sanded chrysotile-containing joint compound prepared by the historical method yielded fiber counts significantly greater (average of 1.7-fold, 95% confidence interval: 1.5- to 2.0-fold) than those obtained by the current method. In addition, air samples prepared by Method 7402 using acetic acid/dimethylformamide yielded fiber counts that were greater (2.8-fold, 95% confidence interval: 2.5- to 3.2-fold) than those prepared by this method using acetone. These results indicated (1) there is an interaction between Method P&CAM 239 preparation chemicals and the carbonate-based joint compound matrix that reveals fibers that were previously bound in the matrix, and (2) the same appeared to be true for Method 7402 preparation chemicals acetic acid/dimethylformamide. This difference in fiber counts is the opposite of what has been reported historically for samples of relatively pure chrysotile dusts prepared using the same chemicals. This preparation artifact should be considered when interpreting historical air samples for drywall workers prepared by Method P&CAM 239. Copyright © 2011 JOEH, LLC

  12. Solventless and solvent-minimized sample preparation techniques for determining currently used pesticides in water samples: a review.

    PubMed

    Tankiewicz, Maciej; Fenik, Jolanta; Biziuk, Marek

    2011-10-30

    The intensification of agriculture means that increasing amounts of toxic organic and inorganic compounds are entering the environment. The pesticides generally applied nowadays are regarded as some of the most dangerous contaminants of the environment. Their presence in the environment, especially in water, is hazardous because they cause human beings to become more susceptible to disease. For these reasons, it is essential to monitor pesticide residues in the environment with the aid of all accessible analytical methods. The analysis of samples for the presence of pesticides is problematic, because of the laborious and time-consuming operations involved in preparing samples for analysis, which themselves may be a source of additional contaminations and errors. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solventless and solvent-minimized techniques are coming into use. This paper discusses the most commonly used over the last 15 years sample preparation techniques for monitoring organophosphorus and organonitrogen pesticides residue in water samples. Furthermore, a significant trend in sample preparation, in accordance with the principles of 'Green Chemistry' is the simplification, miniaturization and automation of analytical techniques. In view of this aspect, several novel techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. The paper describes extraction techniques requiring the use of solvents - liquid-liquid extraction (LLE) and its modifications, membrane extraction techniques, hollow fibre-protected two-phase solvent microextraction, liquid phase microextraction based on the solidification of a floating organic drop (LPME-SFO), solid-phase extraction (SPE) and single-drop microextraction (SDME) - as well as solvent

  13. The NOSAMS sample preparation laboratory in the next millenium: Progress after the WOCE program

    NASA Astrophysics Data System (ADS)

    Gagnon, Alan R.; McNichol, Ann P.; Donoghue, Joanne C.; Stuart, Dana R.; von Reden, Karl; Nosams

    2000-10-01

    Since 1991, the primary charge of the National Ocean Sciences AMS (NOSAMS) facility at the Woods Hole Oceanographic Institution has been to supply high throughput, high precision AMS 14C analyses for seawater samples collected as part of the World Ocean Circulation Experiment (WOCE). Approximately 13,000 samples taken as part of WOCE should be fully analyzed by the end of Y2K. Additional sample sources and techniques must be identified and incorporated if NOSAMS is to continue in its present operation mode. A trend in AMS today is the ability to routinely process and analyze radiocarbon samples that contain tiny amounts (<100 μg) of carbon. The capability to mass-produce small samples for 14C analysis has been recognized as a major facility goal. The installation of a new 134-position MC-SNICS ion source, which utilizes a smaller graphite target cartridge than presently used, is one step towards realizing this goal. New preparation systems constructed in the sample preparation laboratory (SPL) include an automated bank of 10 small-volume graphite reactors, an automated system to process organic carbon samples, and a multi-dimensional preparative capillary gas chromatograph (PCGC).

  14. Standardized Sample Preparation Using a Drop-on-Demand Printing Platform

    DTIC Science & Technology

    2013-05-07

    successful and robust methodology for energetic sample preparation. Keywords: drop-on-demand; inkjet printing; sample preparation OPEN ACCESS...on a similar length scale. Recently, drop-on-demand inkjet printing technology has emerged as an effective approach to produce test materials to...which most of the material is concentrated along the edges, samples prepared using drop-on-demand inkjet technology demonstrate excellent uniform

  15. [Recent advances in sample preparation methods of plant hormones].

    PubMed

    Wu, Qian; Wang, Lus; Wu, Dapeng; Duan, Chunfeng; Guan, Yafeng

    2014-04-01

    Plant hormones are a group of naturally occurring trace substances which play a crucial role in controlling the plant development, growth and environment response. With the development of the chromatography and mass spectroscopy technique, chromatographic analytical method has become a widely used way for plant hormone analysis. Among the steps of chromatographic analysis, sample preparation is undoubtedly the most vital one. Thus, a highly selective and efficient sample preparation method is critical for accurate identification and quantification of phytohormones. For the three major kinds of plant hormones including acidic plant hormones & basic plant hormones, brassinosteroids and plant polypeptides, the sample preparation methods are reviewed in sequence especially the recently developed methods. The review includes novel methods, devices, extractive materials and derivative reagents for sample preparation of phytohormones analysis. Especially, some related works of our group are included. At last, the future developments in this field are also prospected.

  16. Current trends in sample preparation for cosmetic analysis.

    PubMed

    Zhong, Zhixiong; Li, Gongke

    2017-01-01

    The widespread applications of cosmetics in modern life make their analysis particularly important from a safety point of view. There is a wide variety of restricted ingredients and prohibited substances that primarily influence the safety of cosmetics. Sample preparation for cosmetic analysis is a crucial step as the complex matrices may seriously interfere with the determination of target analytes. In this review, some new developments (2010-2016) in sample preparation techniques for cosmetic analysis, including liquid-phase microextraction, solid-phase microextraction, matrix solid-phase dispersion, pressurized liquid extraction, cloud point extraction, ultrasound-assisted extraction, and microwave digestion, are presented. Furthermore, the research and progress in sample preparation techniques and their applications in the separation and purification of allowed ingredients and prohibited substances are reviewed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Recent Developments in Sample Preparation for Mass Spectrometry-Based Metabolomics.

    PubMed

    Gong, Zhi-Gang; Hu, Jing; Wu, Xi; Xu, Yong-Jiang

    2017-07-04

    Metabolomics is a critical member in systems biology. Although great progress has been achieved in metabolomics, there are still some problems in sample preparation, data processing and data interpretation. In this review, we intend to explore the roles, challenges and trends in sample preparation for mass spectrometry- (MS-) based metabolomics. The newly emerged sample preparation methods were also critically examined, including laser microdissection, in vivo sampling, dried blood spot, microwave, ultrasound and enzyme-assisted extraction, as well as microextraction techniques. Finally, we provide some conclusions and perspectives for sample preparation in MS-based metabolomics.

  18. The planning and establishment of a sample preparation laboratory for drug discovery

    PubMed Central

    Dufresne, Claude

    2000-01-01

    Nature has always been a productive source of new drugs. With the advent of high-throughput screening, it has now become possible to rapidly screen large sample collections. In addition to seeking greater diversity from natural product sources (micro-organisms, plants, etc.), fractionation of the crude extracts prior to screening is becoming a more important part of our efforts. As sample preparation protocols become more involved, automation can help to achieve and maintain a desired sample throughput. To address the needs of our screening program, two robotic systems were designed. The first system processes crude extracts all the way to 96-well plates, containing solutions suitable for screening in biological and biochemical assays. The system can dissolve crude extracts, fractionate them on solid-phase extraction cartridges, dry and weigh each fraction, re-dissolve them to a known concentration, and prepare mother plates. The second system replicates mother plates into a number of daughter plates. PMID:18924691

  19. Sample preparation prior to the LC-MS-based metabolomics/metabonomics of blood-derived samples.

    PubMed

    Gika, Helen; Theodoridis, Georgios

    2011-07-01

    Blood represents a very important biological fluid and has been the target of continuous and extensive research for diagnostic, or health and drug monitoring reasons. Recently, metabonomics/metabolomics have emerged as a new and promising 'omics' platform that shows potential in biomarker discovery, especially in areas such as disease diagnosis, assessment of drug efficacy or toxicity. Blood is collected in various establishments in conditions that are not standardized. Next, the samples are prepared and analyzed using different methodologies or tools. When targeted analysis of key molecules (e.g., a drug or its metabolite[s]) is the aim, enforcement of certain measures or additional analyses may correct and harmonize these discrepancies. In omics fields such as those performed by holistic analytical approaches, no such rules or tools are available. As a result, comparison or correlation of results or data fusion becomes impractical. However, it becomes evident that such obstacles should be overcome in the near future to allow for large-scale studies that involve the assaying of samples from hundreds of individuals. In this case the effect of sample handling and preparation becomes very serious, in order to avoid wasting months of work from experts and expensive instrument time. The present review aims to cover the different methodologies applied to the pretreatment of blood prior to LC-MS metabolomic/metabonomic studies. The article tries to critically compare the methods and highlight issues that need to be addressed.

  20. 7 CFR 61.34 - Drawing and preparation of sample.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Drawing and preparation of sample. 61.34 Section 61.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Cottonseed Samplers § 61.34 Drawing and preparation of sample. Each licensed cottonseed sampler shall draw...

  1. High-throughput automated microfluidic sample preparation for accurate microbial genomics

    PubMed Central

    Kim, Soohong; De Jonghe, Joachim; Kulesa, Anthony B.; Feldman, David; Vatanen, Tommi; Bhattacharyya, Roby P.; Berdy, Brittany; Gomez, James; Nolan, Jill; Epstein, Slava; Blainey, Paul C.

    2017-01-01

    Low-cost shotgun DNA sequencing is transforming the microbial sciences. Sequencing instruments are so effective that sample preparation is now the key limiting factor. Here, we introduce a microfluidic sample preparation platform that integrates the key steps in cells to sequence library sample preparation for up to 96 samples and reduces DNA input requirements 100-fold while maintaining or improving data quality. The general-purpose microarchitecture we demonstrate supports workflows with arbitrary numbers of reaction and clean-up or capture steps. By reducing the sample quantity requirements, we enabled low-input (∼10,000 cells) whole-genome shotgun (WGS) sequencing of Mycobacterium tuberculosis and soil micro-colonies with superior results. We also leveraged the enhanced throughput to sequence ∼400 clinical Pseudomonas aeruginosa libraries and demonstrate excellent single-nucleotide polymorphism detection performance that explained phenotypically observed antibiotic resistance. Fully-integrated lab-on-chip sample preparation overcomes technical barriers to enable broader deployment of genomics across many basic research and translational applications. PMID:28128213

  2. Improved sample preparation and counting techniques for enhanced tritium measurement sensitivity

    NASA Astrophysics Data System (ADS)

    Moran, J.; Aalseth, C.; Bailey, V. L.; Mace, E. K.; Overman, C.; Seifert, A.; Wilcox Freeburg, E. D.

    2015-12-01

    Tritium (T) measurements offer insight to a wealth of environmental applications including hydrologic tracking, discerning ocean circulation patterns, and aging ice formations. However, the relatively short half-life of T (12.3 years) limits its effective age dating range. Compounding this limitation is the decrease in atmospheric T content by over two orders of magnitude (from 1000-2000 TU in 1962 to < 10 TU currently) since the cessation of above ground nuclear testing in the 1960's. We are developing sample preparation methods coupled to direct counting of T via ultra-low background proportional counters which, when combined, offer improved T measurement sensitivity (~4.5 mmoles of H2 equivalent) and will help expand the application of T age dating to smaller sample sizes linked to persistent environmental questions despite the limitations above. For instance, this approach can be used to T date ~ 2.2 mmoles of CH4 collected from sample-limited systems including microbial communities, soils, or subsurface aquifers and can be combined with radiocarbon dating to distinguish the methane's formation age from C age in a system. This approach can also expand investigations into soil organic C where the improved sensitivity will permit resolution of soil C into more descriptive fractions and provide direct assessments of the stability of specific classes of organic matter in soils environments. We are employing a multiple step sample preparation system whereby organic samples are first combusted with resulting CO2 and H2O being used as a feedstock to synthesize CH4. This CH4 is mixed with Ar and loaded directly into an ultra-low background proportional counter for measurement of T β decay in a shallow underground laboratory. Analysis of water samples requires only the addition of geologic CO2 feedstock with the sample for methane synthesis. The chemical nature of the preparation techniques enable high sample throughput with only the final measurement requiring T decay

  3. Solid matrix transformation and tracer addition using molten ammonium bifluoride salt as a sample preparation method for laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Grate, Jay W; Gonzalez, Jhanis J; O'Hara, Matthew J; Kellogg, Cynthia M; Morrison, Samuel S; Koppenaal, David W; Chan, George C-Y; Mao, Xianglei; Zorba, Vassilia; Russo, Richard E

    2017-09-08

    Solid sampling and analysis methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), are challenged by matrix effects and calibration difficulties. Matrix-matched standards for external calibration are seldom available and it is difficult to distribute spikes evenly into a solid matrix as internal standards. While isotopic ratios of the same element can be measured to high precision, matrix-dependent effects in the sampling and analysis process frustrate accurate quantification and elemental ratio determinations. Here we introduce a potentially general solid matrix transformation approach entailing chemical reactions in molten ammonium bifluoride (ABF) salt that enables the introduction of spikes as tracers or internal standards. Proof of principle experiments show that the decomposition of uranium ore in sealed PFA fluoropolymer vials at 230 °C yields, after cooling, new solids suitable for direct solid sampling by LA. When spikes are included in the molten salt reaction, subsequent LA-ICP-MS sampling at several spots indicate that the spikes are evenly distributed, and that U-235 tracer dramatically improves reproducibility in U-238 analysis. Precisions improved from 17% relative standard deviation for U-238 signals to 0.1% for the ratio of sample U-238 to spiked U-235, a factor of over two orders of magnitude. These results introduce the concept of solid matrix transformation (SMT) using ABF, and provide proof of principle for a new method of incorporating internal standards into a solid for LA-ICP-MS. This new approach, SMT-LA-ICP-MS, provides opportunities to improve calibration and quantification in solids based analysis. Looking forward, tracer addition to transformed solids opens up LA-based methods to analytical methodologies such as standard addition, isotope dilution, preparation of matrix-matched solid standards, external calibration, and monitoring instrument drift against external calibration standards.

  4. State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

    PubMed

    Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

    2016-01-28

    Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

    NASA Technical Reports Server (NTRS)

    Wittmann, A.; Willay, G.

    1986-01-01

    For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

  6. Effects of sample preparation on the infrared reflectance spectra of powders

    NASA Astrophysics Data System (ADS)

    Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

    2015-05-01

    While reflectance spectroscopy is a useful tool for identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-loaded as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample can have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

  7. Fluidics platform and method for sample preparation and analysis

    DOEpatents

    Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

    2014-08-19

    Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

  8. Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.

    2015-05-22

    While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packedmore » as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.« less

  9. 7 CFR 27.25 - Additional samples of cotton; drawing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Additional samples of cotton; drawing. 27.25 Section... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.25 Additional samples of cotton; drawing. In addition to the samples hereinbefore prescribed...

  10. 7 CFR 27.25 - Additional samples of cotton; drawing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Additional samples of cotton; drawing. 27.25 Section... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.25 Additional samples of cotton; drawing. In addition to the samples hereinbefore prescribed...

  11. 7 CFR 27.25 - Additional samples of cotton; drawing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Additional samples of cotton; drawing. 27.25 Section... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.25 Additional samples of cotton; drawing. In addition to the samples hereinbefore prescribed...

  12. 7 CFR 27.25 - Additional samples of cotton; drawing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Additional samples of cotton; drawing. 27.25 Section... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.25 Additional samples of cotton; drawing. In addition to the samples hereinbefore prescribed...

  13. 7 CFR 27.25 - Additional samples of cotton; drawing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Additional samples of cotton; drawing. 27.25 Section... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.25 Additional samples of cotton; drawing. In addition to the samples hereinbefore prescribed...

  14. New Methods of Sample Preparation for Atom Probe Specimens

    NASA Technical Reports Server (NTRS)

    Kuhlman, Kimberly, R.; Kowalczyk, Robert S.; Ward, Jennifer R.; Wishard, James L.; Martens, Richard L.; Kelly, Thomas F.

    2003-01-01

    Magnetite is a common conductive mineral found on Earth and Mars. Disk-shaped precipitates approximately 40 nm in diameter have been shown to have manganese and aluminum concentrations. Atom-probe field-ion microscopy (APFIM) is the only technique that can potentially quantify the composition of these precipitates. APFIM will be used to characterize geological and planetary materials, analyze samples of interest for geomicrobiology; and, for the metrology of nanoscale instrumentation. Prior to APFIM sample preparation was conducted by electropolishing, the method of sharp shards (MSS), or Bosch process (deep reactive ion etching) with focused ion beam (FIB) milling as a final step. However, new methods are required for difficult samples. Many materials are not easily fabricated using electropolishing, MSS, or the Bosch process, FIB milling is slow and expensive, and wet chemistry and the reactive ion etching are typically limited to Si and other semiconductors. APFIM sample preparation using the dicing saw is commonly used to section semiconductor wafers into individual devices following manufacture. The dicing saw is a time-effective method for preparing high aspect ratio posts of poorly conducting materials. Femtosecond laser micromachining is also suitable for preparation of posts. FIB time required is reduced by about a factor of 10 and multi-tip specimens can easily be fabricated using the dicing saw.

  15. Sample Preparation for Mass Spectrometry Imaging of Plant Tissues: A Review

    PubMed Central

    Dong, Yonghui; Li, Bin; Malitsky, Sergey; Rogachev, Ilana; Aharoni, Asaph; Kaftan, Filip; Svatoš, Aleš; Franceschi, Pietro

    2016-01-01

    Mass spectrometry imaging (MSI) is a mass spectrometry based molecular ion imaging technique. It provides the means for ascertaining the spatial distribution of a large variety of analytes directly on tissue sample surfaces without any labeling or staining agents. These advantages make it an attractive molecular histology tool in medical, pharmaceutical, and biological research. Likewise, MSI has started gaining popularity in plant sciences; yet, information regarding sample preparation methods for plant tissues is still limited. Sample preparation is a crucial step that is directly associated with the quality and authenticity of the imaging results, it therefore demands in-depth studies based on the characteristics of plant samples. In this review, a sample preparation pipeline is discussed in detail and illustrated through selected practical examples. In particular, special concerns regarding sample preparation for plant imaging are critically evaluated. Finally, the applications of MSI techniques in plants are reviewed according to different classes of plant metabolites. PMID:26904042

  16. Preparation of Chemical Samples On Relevant Surfaces Using Inkjet Technology

    DTIC Science & Technology

    2013-04-01

    PREPARATION OF CHEMICAL SAMPLES ON RELEVANT SURFACES USING INKJET TECHNOLOGY...2012 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Preparation of Chemical Samples on Relevant Surfaces Using Inkjet Technology 5b. GRANT NUMBER...SUBJECT TERMS Surface detection Inkjet Simulant deposition 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF

  17. Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

    PubMed Central

    Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

    2017-01-01

    Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

  18. Sample preparation and EFTEM of Meat Samples for Nanoparticle Analysis in Food

    NASA Astrophysics Data System (ADS)

    Lari, L.; Dudkiewicz, A.

    2014-06-01

    Nanoparticles are used in industry for personal care products and the preparation of food. In the latter application, their functions include the prevention of microbes' growth, increase of the foods nutritional value and sensory quality. EU regulations require a risk assessment of the nanoparticles used in foods and food contact materials before the products can reach the market. However, availability of validated analytical methodologies for detection and characterisation of the nanoparticles in food hampers appropriate risk assessment. As part of a research on the evaluation of the methods for screening and quantification of Ag nanoparticles in meat we have tested a new TEM sample preparation alternative to resin embedding and cryo-sectioning. Energy filtered TEM analysis was applied to evaluate thickness and the uniformity of thin meat layers acquired at increasing input of the sample demonstrating that the protocols used ensured good stability under the electron beam, reliable sample concentration and reproducibility.

  19. Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.

    2007-12-01

    The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includesmore » an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.« less

  20. MALDI (matrix assisted laser desorption ionization) Imaging Mass Spectrometry (IMS) of skin: Aspects of sample preparation.

    PubMed

    de Macedo, Cristiana Santos; Anderson, David M; Schey, Kevin L

    2017-11-01

    MALDI (matrix assisted laser desorption ionization) Imaging Mass Spectrometry (IMS) allows molecular analysis of biological materials making possible the identification and localization of molecules in tissues, and has been applied to address many questions on skin pathophysiology, as well as on studies about drug absorption and metabolism. Sample preparation for MALDI IMS is the most important part of the workflow, comprising specimen collection and preservation, tissue embedding, cryosectioning, washing, and matrix application. These steps must be carefully optimized for specific analytes of interest (lipids, proteins, drugs, etc.), representing a challenge for skin analysis. In this review, critical parameters for MALDI IMS sample preparation of skin samples will be described. In addition, specific applications of MALDI IMS of skin samples will be presented including wound healing, neoplasia, and infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Preparation of protein samples for mass spectrometry and N-terminal sequencing.

    PubMed

    Glenn, Gary

    2014-01-01

    The preparation of protein samples for mass spectrometry and N-terminal sequencing is a key step in successfully identifying proteins. Mass spectrometry is a very sensitive technique, and as such, samples must be prepared carefully since they can be subject to contamination of the sample (e.g., due to incomplete subcellular fractionation or purification of a multiprotein complex), overwhelming of the sample by highly abundant proteins, and contamination from skin or hair (keratin can be a very common hit). One goal of sample preparation for mass spec is to reduce the complexity of the sample - in the example presented here, mitochondria are purified, solubilized, and fractionated by sucrose density gradient sedimentation prior to preparative 1D SDS-PAGE. It is important to verify the purity and integrity of the sample so that you can have confidence in the hits obtained. More protein is needed for N-terminal sequencing and ideally it should be purified to a single band when run on an SDS-polyacrylamide gel. The example presented here involves stably expressing a tagged protein in HEK293 cells and then isolating the protein by affinity purification and SDS-PAGE. © 2014 Elsevier Inc. All rights reserved.

  2. Molecularly imprinted polymers for sample preparation and biosensing in food analysis: Progress and perspectives.

    PubMed

    Ashley, Jon; Shahbazi, Mohammad-Ali; Kant, Krishna; Chidambara, Vinayaka Aaydha; Wolff, Anders; Bang, Dang Duong; Sun, Yi

    2017-05-15

    Molecularly imprinted polymers (MIPs) are biomimetics which can selectively bind to analytes of interest. One of the most interesting areas where MIPs have shown the biggest potential is food analysis. MIPs have found use as sorbents in sample preparation attributed to the high selectivity and high loading capacity. MIPs have been intensively employed in classical solid-phase extraction and solid-phase microextraction. More recently, MIPs have been combined with magnetic bead extraction, which greatly simplifies sample handling procedures. Studies have consistently shown that MIPs can effectively minimize complex food matrix effects, and improve recoveries and detection limits. In addition to sample preparation, MIPs have also been viewed as promising alternatives to bio-receptors due to the inherent molecular recognition abilities and the high stability in harsh chemical and physical conditions. MIPs have been utilized as receptors in biosensing platforms such as electrochemical, optical and mass biosensors to detect various analytes in food. In this review, we will discuss the current state-of-the-art of MIP synthesis and applications in the context of food analysis. We will highlight the imprinting methods which are applicable for imprinting food templates, summarize the recent progress in using MIPs for preparing and analysing food samples, and discuss the current limitations in the commercialisation of MIPs technology. Finally, future perspectives will be given. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Novel strategies for sample preparation in forensic toxicology.

    PubMed

    Samanidou, Victoria; Kovatsi, Leda; Fragou, Domniki; Rentifis, Konstantinos

    2011-09-01

    This paper provides a review of novel strategies for sample preparation in forensic toxicology. The review initially outlines the principle of each technique, followed by sections addressing each class of abused drugs separately. The novel strategies currently reviewed focus on the preparation of various biological samples for the subsequent determination of opiates, benzodiazepines, amphetamines, cocaine, hallucinogens, tricyclic antidepressants, antipsychotics and cannabinoids. According to our experience, these analytes are the most frequently responsible for intoxications in Greece. The applications of techniques such as disposable pipette extraction, microextraction by packed sorbent, matrix solid-phase dispersion, solid-phase microextraction, polymer monolith microextraction, stir bar sorptive extraction and others, which are rapidly gaining acceptance in the field of toxicology, are currently reviewed.

  4. Reducing Time and Increasing Sensitivity in Sample Preparation for Adherent Mammalian Cell Metabolomics

    PubMed Central

    Lorenz, Matthew A.; Burant, Charles F.; Kennedy, Robert T.

    2011-01-01

    A simple, fast, and reproducible sample preparation procedure was developed for relative quantification of metabolites in adherent mammalian cells using the clonal β-cell line INS-1 as a model sample. The method was developed by evaluating the effect of different sample preparation procedures on high performance liquid chromatography- mass spectrometry quantification of 27 metabolites involved in glycolysis and the tricarboxylic acid cycle on a directed basis as well as for all detectable chromatographic features on an undirected basis. We demonstrate that a rapid water rinse step prior to quenching of metabolism reduces components that suppress electrospray ionization thereby increasing signal for 26 of 27 targeted metabolites and increasing total number of detected features from 237 to 452 with no detectable change of metabolite content. A novel quenching technique is employed which involves addition of liquid nitrogen directly to the culture dish and allows for samples to be stored at −80 °C for at least 7 d before extraction. Separation of quenching and extraction steps provides the benefit of increased experimental convenience and sample stability while maintaining metabolite content similar to techniques that employ simultaneous quenching and extraction with cold organic solvent. The extraction solvent 9:1 methanol: chloroform was found to provide superior performance over acetonitrile, ethanol, and methanol with respect to metabolite recovery and extract stability. Maximal recovery was achieved using a single rapid (~1 min) extraction step. The utility of this rapid preparation method (~5 min) was demonstrated through precise metabolite measurements (11% average relative standard deviation without internal standards) associated with step changes in glucose concentration that evoke insulin secretion in the clonal β-cell line INS-1. PMID:21456517

  5. Cytology Preparations of Formalin Fixative Aid Detection of Giardia in Duodenal Biopsy Samples.

    PubMed

    Panarelli, Nicole C; Gobara, Nariman; Hoda, Rana S; Chaump, Michael; Jessurun, Jose; Yantiss, Rhonda K

    2017-04-01

    Giardiasis is the most common intestinal parasitic infection in the United States. The organism elicits no, or minimal, inflammatory changes in duodenal biopsy samples, so it can be easily overlooked. We performed this study to determine whether Giardia could be isolated from the formalin fixative of biopsy samples, and to evaluate the value of fluid analysis in the assessment for potential infection. We prospectively evaluated duodenal biopsy samples from 92 patients with a clinical suspicion of giardiasis or symptoms compatible with that diagnosis (ie, diarrhea, bloating, or abdominal pain) Biopsy samples were routinely processed and stained with hematoxylin and eosin. Histologic diagnoses included giardiasis (5 cases, 4%), normal findings (64 cases, 70%), peptic injury/active duodenitis (12 cases, 13%), and intraepithelial lymphocytosis with villous blunting (10 cases, 12%). Fifteen cases (13%) showed detached degenerated epithelial cells or mucus droplets in the intervillous space that resembled Giardia. Cytology slides were prepared from formalin in the biopsy container using the standard Cytospin protocol and reviewed by a cytopathologist blinded to the biopsy findings. Cytologic evaluation revealed Giardia spp. in all 5 biopsy-proven cases, and identified an additional case that was not detected by biopsy analysis. Organisms were significantly more numerous (mean: 400 trophozoites; range, 120 to 810) and showed better morphologic features in cytology preparations compared with tissue sections (mean: 129 trophozoites; range, 37 to 253 organisms; P=0.05). Our findings suggest that cytology preparations from formalin fixative can resolve diagnostically challenging cases and even enhance Giardia detection in some cases.

  6. Review of sample preparation strategies for MS-based metabolomic studies in industrial biotechnology.

    PubMed

    Causon, Tim J; Hann, Stephan

    2016-09-28

    Fermentation and cell culture biotechnology in the form of so-called "cell factories" now play an increasingly significant role in production of both large (e.g. proteins, biopharmaceuticals) and small organic molecules for a wide variety of applications. However, associated metabolic engineering optimisation processes relying on genetic modification of organisms used in cell factories, or alteration of production conditions remain a challenging undertaking for improving the final yield and quality of cell factory products. In addition to genomic, transcriptomic and proteomic workflows, analytical metabolomics continues to play a critical role in studying detailed aspects of critical pathways (e.g. via targeted quantification of metabolites), identification of biosynthetic intermediates, and also for phenotype differentiation and the elucidation of previously unknown pathways (e.g. via non-targeted strategies). However, the diversity of primary and secondary metabolites and the broad concentration ranges encompassed during typical biotechnological processes means that simultaneous extraction and robust analytical determination of all parts of interest of the metabolome is effectively impossible. As the integration of metabolome data with transcriptome and proteome data is an essential goal of both targeted and non-targeted methods addressing production optimisation goals, additional sample preparation steps beyond necessary sampling, quenching and extraction protocols including clean-up, analyte enrichment, and derivatisation are important considerations for some classes of metabolites, especially those present in low concentrations or exhibiting poor stability. This contribution critically assesses the potential of current sample preparation strategies applied in metabolomic studies of industrially-relevant cell factory organisms using mass spectrometry-based platforms primarily coupled to liquid-phase sample introduction (i.e. flow injection, liquid

  7. Sample Preparation Report of the Fourth OPCW Confidence Building Exercise on Biomedical Sample Analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Udey, R. N.; Corzett, T. H.; Alcaraz, A.

    Following the successful completion of the 3rd biomedical confidence building exercise (February 2013 – March 2013), which included the analysis of plasma and urine samples spiked at low ppb levels as part of the exercise scenario, another confidence building exercise was targeted to be conducted in 2014. In this 4th exercise, it was desired to focus specifically on the analysis of plasma samples. The scenario was designed as an investigation of an alleged use of chemical weapons where plasma samples were collected, as plasma has been reported to contain CWA adducts which remain present in the human body for severalmore » weeks (Solano et al. 2008). In the 3rd exercise most participants used the fluoride regeneration method to analyze for the presence of nerve agents in plasma samples. For the 4th biomedical exercise it was decided to evaluate the analysis of human plasma samples for the presence/absence of the VX adducts and aged adducts to blood proteins (e.g., VX-butyrylcholinesterase (BuChE) and aged BuChE adducts using a pepsin digest technique to yield nonapeptides; or equivalent). As the aging of VX-BuChE adducts is relatively slow (t1/2 = 77 hr at 37 °C [Aurbek et al. 2009]), soman (GD), which ages much more quickly (t1/2 = 9 min at 37 °C [Masson et al. 2010]), was used to simulate an aged VX sample. Additional objectives of this exercise included having laboratories assess novel OP-adducted plasma sample preparation techniques and analytical instrumentation methodologies, as well as refining/designating the reporting formats for these new techniques.« less

  8. Final Report for X-ray Diffraction Sample Preparation Method Development

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ely, T. M.; Meznarich, H. K.; Valero, T.

    WRPS-1500790, “X-ray Diffraction Saltcake Sample Preparation Method Development Plan/Procedure,” was originally prepared with the intent of improving the specimen preparation methodology used to generate saltcake specimens suitable for XRD-based solid phase characterization. At the time that this test plan document was originally developed, packed powder in cavity supports with collodion binder was the established XRD specimen preparation method. An alternate specimen preparation method less vulnerable, if not completely invulnerable to preferred orientation effects, was desired as a replacement for the method.

  9. Automated SEM and TEM sample preparation applied to copper/low k materials

    NASA Astrophysics Data System (ADS)

    Reyes, R.; Shaapur, F.; Griffiths, D.; Diebold, A. C.; Foran, B.; Raz, E.

    2001-01-01

    We describe the use of automated microcleaving for preparation of both SEM and TEM samples as done by SELA's new MC500 and TEMstation tools. The MC500 is an automated microcleaving tool that is capable of producing cleaves with 0.25 μm accuracy resulting in SEM-ready samples. The TEMstation is capable of taking a sample output from the MC500 (or from SELA's earlier MC200 tool) and producing a FIB ready slice of 25±5 μm, mounted on a TEM-washer and ready for FIB thinning to electron transparency for TEM analysis. The materials selected for the tool set evaluation mainly included the Cu/TaN/HOSP low-k system. The paper is divided into three sections, experimental approach, SEM preparation and analysis of HOSP low-k, and TEM preparation and analysis of Cu/TaN/HOSP low-k samples. For the samples discussed, data is presented to show the quality of preparation provided by these new automated tools.

  10. Polymeric ionic liquid-based portable tip microextraction device for on-site sample preparation of water samples.

    PubMed

    Chen, Lei; Pei, Junxian; Huang, Xiaojia; Lu, Min

    2018-06-05

    On-site sample preparation is highly desired because it avoids the transportation of large-volume samples and ensures the accuracy of the analytical results. In this work, a portable prototype of tip microextraction device (TMD) was designed and developed for on-site sample pretreatment. The assembly procedure of TMD is quite simple. Firstly, polymeric ionic liquid (PIL)-based adsorbent was in-situ prepared in a pipette tip. After that, the tip was connected with a syringe which was driven by a bidirectional motor. The flow rates in adsorption and desorption steps were controlled accurately by the motor. To evaluate the practicability of the developed device, the TMD was used to on-site sample preparation of waters and combined with high-performance liquid chromatography with diode array detection to measure trace estrogens in water samples. Under the most favorable conditions, the limits of detection (LODs, S/N = 3) for the target analytes were in the range of 4.9-22 ng/L, with good coefficients of determination. Confirmatory study well evidences that the extraction performance of TMD is comparable to that of the traditional laboratory solid-phase extraction process, but the proposed TMD is more simple and convenient. At the same time, the TMD avoids complicated sampling and transferring steps of large-volume water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Evaluation of sample preparation methods for the analysis of papaya leaf proteins through two-dimensional gel electrophoresis.

    PubMed

    Rodrigues, Silas Pessini; Ventura, José Aires; Zingali, R B; Fernandes, P M B

    2009-01-01

    A variety of sample preparation protocols for plant proteomic analysis using two-dimensional gel electrophoresis (2-DE) have been reported. However, they usually have to be adapted and further optimised for the analysis of plant species not previously studied. This work aimed to evaluate different sample preparation protocols for analysing Carica papaya L. leaf proteins through 2-DE. Four sample preparation methods were tested: (1) phenol extraction and methanol-ammonium acetate precipitation; (2) no precipitation fractionation; and the traditional trichloroacetic acid-acetone precipitation either (3) with or (4) without protein fractionation. The samples were analysed for their compatibility with SDS-PAGE (1-DE) and 2-DE. Fifteen selected protein spots were trypsinised and analysed by matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS), followed by a protein search using the NCBInr database to accurately identify all proteins. Methods number 3 and 4 resulted in large quantities of protein with good 1-DE separation and were chosen for 2-DE analysis. However, only the TCA method without fractionation (no. 4) proved to be useful. Spot number and resolution advances were achieved, which included having an additional solubilisation step in the conventional TCA method. Moreover, most of the theoretical and experimental protein molecular weight and pI data had similar values, suggesting good focusing and, most importantly, limited protein degradation. The described sample preparation method allows the proteomic analysis of papaya leaves by 2-DE and mass spectrometry (MALDI-TOF-MS/MS). The methods presented can be a starting point for the optimisation of sample preparation protocols for other plant species.

  12. Optimization of Sample Preparation processes of Bone Material for Raman Spectroscopy.

    PubMed

    Chikhani, Madelen; Wuhrer, Richard; Green, Hayley

    2018-03-30

    Raman spectroscopy has recently been investigated for use in the calculation of postmortem interval from skeletal material. The fluorescence generated by samples, which affects the interpretation of Raman data, is a major limitation. This study compares the effectiveness of two sample preparation techniques, chemical bleaching and scraping, in the reduction of fluorescence from bone samples during testing with Raman spectroscopy. Visual assessment of Raman spectra obtained at 1064 nm excitation following the preparation protocols indicates an overall reduction in fluorescence. Results demonstrate that scraping is more effective at resolving fluorescence than chemical bleaching. The scraping of skeletonized remains prior to Raman analysis is a less destructive method and allows for the preservation of a bone sample in a state closest to its original form, which is beneficial in forensic investigations. It is recommended that bone scraping supersedes chemical bleaching as the preferred method for sample preparation prior to Raman spectroscopy. © 2018 American Academy of Forensic Sciences.

  13. Magnetic separation techniques in sample preparation for biological analysis: a review.

    PubMed

    He, Jincan; Huang, Meiying; Wang, Dongmei; Zhang, Zhuomin; Li, Gongke

    2014-12-01

    Sample preparation is a fundamental and essential step in almost all the analytical procedures, especially for the analysis of complex samples like biological and environmental samples. In past decades, with advantages of superparamagnetic property, good biocompatibility and high binding capacity, functionalized magnetic materials have been widely applied in various processes of sample preparation for biological analysis. In this paper, the recent advancements of magnetic separation techniques based on magnetic materials in the field of sample preparation for biological analysis were reviewed. The strategy of magnetic separation techniques was summarized. The synthesis, stabilization and bio-functionalization of magnetic nanoparticles were reviewed in detail. Characterization of magnetic materials was also summarized. Moreover, the applications of magnetic separation techniques for the enrichment of protein, nucleic acid, cell, bioactive compound and immobilization of enzyme were described. Finally, the existed problems and possible trends of magnetic separation techniques for biological analysis in the future were proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Preparation of Cytology Samples: Tricks of the Trade.

    PubMed

    Moore, A Russell

    2017-01-01

    General principles and techniques for collection, preparation, and staining of cytologic samples in the general practice setting are reviewed. Tips for collection of digital images are also discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Assessment of Sample Preparation Bias in Mass Spectrometry-Based Proteomics.

    PubMed

    Klont, Frank; Bras, Linda; Wolters, Justina C; Ongay, Sara; Bischoff, Rainer; Halmos, Gyorgy B; Horvatovich, Péter

    2018-04-17

    For mass spectrometry-based proteomics, the selected sample preparation strategy is a key determinant for information that will be obtained. However, the corresponding selection is often not based on a fit-for-purpose evaluation. Here we report a comparison of in-gel (IGD), in-solution (ISD), on-filter (OFD), and on-pellet digestion (OPD) workflows on the basis of targeted (QconCAT-multiple reaction monitoring (MRM) method for mitochondrial proteins) and discovery proteomics (data-dependent acquisition, DDA) analyses using three different human head and neck tissues (i.e., nasal polyps, parotid gland, and palatine tonsils). Our study reveals differences between the sample preparation methods, for example, with respect to protein and peptide losses, quantification variability, protocol-induced methionine oxidation, and asparagine/glutamine deamidation as well as identification of cysteine-containing peptides. However, none of the methods performed best for all types of tissues, which argues against the existence of a universal sample preparation method for proteome analysis.

  16. 21 CFR 71.4 - Samples; additional information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR... samples of the color additive, articles used as components thereof, or of the food, drug, or cosmetic in... additive, or articles used as components thereof, or of the food, drug, or cosmetic in which the color...

  17. 21 CFR 71.4 - Samples; additional information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR... samples of the color additive, articles used as components thereof, or of the food, drug, or cosmetic in... additive, or articles used as components thereof, or of the food, drug, or cosmetic in which the color...

  18. 21 CFR 71.4 - Samples; additional information.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR... samples of the color additive, articles used as components thereof, or of the food, drug, or cosmetic in... additive, or articles used as components thereof, or of the food, drug, or cosmetic in which the color...

  19. 21 CFR 71.4 - Samples; additional information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR... samples of the color additive, articles used as components thereof, or of the food, drug, or cosmetic in... additive, or articles used as components thereof, or of the food, drug, or cosmetic in which the color...

  20. 21 CFR 71.4 - Samples; additional information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR... samples of the color additive, articles used as components thereof, or of the food, drug, or cosmetic in... additive, or articles used as components thereof, or of the food, drug, or cosmetic in which the color...

  1. Applications of reversible covalent chemistry in analytical sample preparation.

    PubMed

    Siegel, David

    2012-12-07

    Reversible covalent chemistry (RCC) adds another dimension to commonly used sample preparation techniques like solid-phase extraction (SPE), solid-phase microextraction (SPME), molecular imprinted polymers (MIPs) or immuno-affinity cleanup (IAC): chemical selectivity. By selecting analytes according to their covalent reactivity, sample complexity can be reduced significantly, resulting in enhanced analytical performance for low-abundance target analytes. This review gives a comprehensive overview of the applications of RCC in analytical sample preparation. The major reactions covered include reversible boronic ester formation, thiol-disulfide exchange and reversible hydrazone formation, targeting analyte groups like diols (sugars, glycoproteins and glycopeptides, catechols), thiols (cysteinyl-proteins and cysteinyl-peptides) and carbonyls (carbonylated proteins, mycotoxins). Their applications range from low abundance proteomics to reversible protein/peptide labelling to antibody chromatography to quantitative and qualitative food analysis. In discussing the potential of RCC, a special focus is on the conditions and restrictions of the utilized reaction chemistry.

  2. Additional Samples: Where They Should Be Located

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pilger, G. G., E-mail: jfelipe@ufrgs.br; Costa, J. F. C. L.; Koppe, J. C.

    2001-09-15

    Information for mine planning requires to be close spaced, if compared to the grid used for exploration and resource assessment. The additional samples collected during quasimining usually are located in the same pattern of the original diamond drillholes net but closer spaced. This procedure is not the best in mathematical sense for selecting a location. The impact of an additional information to reduce the uncertainty about the parameter been modeled is not the same everywhere within the deposit. Some locations are more sensitive in reducing the local and global uncertainty than others. This study introduces a methodology to select additionalmore » sample locations based on stochastic simulation. The procedure takes into account data variability and their spatial location. Multiple equally probable models representing a geological attribute are generated via geostatistical simulation. These models share basically the same histogram and the same variogram obtained from the original data set. At each block belonging to the model a value is obtained from the n simulations and their combination allows one to access local variability. Variability is measured using an uncertainty index proposed. This index was used to map zones of high variability. A value extracted from a given simulation is added to the original data set from a zone identified as erratic in the previous maps. The process of adding samples and simulation is repeated and the benefit of the additional sample is evaluated. The benefit in terms of uncertainty reduction is measure locally and globally. The procedure showed to be robust and theoretically sound, mapping zones where the additional information is most beneficial. A case study in a coal mine using coal seam thickness illustrates the method.« less

  3. Author Contribution to the Pu Handbook II: Chapter 37 LLNL Integrated Sample Preparation Glovebox (TEM) Section

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wall, Mark A.

    The development of our Integrated Actinide Sample Preparation Laboratory (IASPL) commenced in 1998 driven by the need to perform transmission electron microscopy studies on naturally aged plutonium and its alloys looking for the microstructural effects of the radiological decay process (1). Remodeling and construction of a laboratory within the Chemistry and Materials Science Directorate facilities at LLNL was required to turn a standard radiological laboratory into a Radiological Materials Area (RMA) and Radiological Buffer Area (RBA) containing type I, II and III workplaces. Two inert atmosphere dry-train glove boxes with antechambers and entry/exit fumehoods (Figure 1), having a baseline atmospheremore » of 1 ppm oxygen and 1 ppm water vapor, a utility fumehood and a portable, and a third double-walled enclosure have been installed and commissioned. These capabilities, along with highly trained technical staff, facilitate the safe operation of sample preparation processes and instrumentation, and sample handling while minimizing oxidation or corrosion of the plutonium. In addition, we are currently developing the capability to safely transfer small metallographically prepared samples to a mini-SEM for microstructural imaging and chemical analysis. The gloveboxes continue to be the most crucial element of the laboratory allowing nearly oxide-free sample preparation for a wide variety of LLNL-based characterization experiments, which includes transmission electron microscopy, electron energy loss spectroscopy, optical microscopy, electrical resistivity, ion implantation, X-ray diffraction and absorption, magnetometry, metrological surface measurements, high-pressure diamond anvil cell equation-of-state, phonon dispersion measurements, X-ray absorption and emission spectroscopy, and differential scanning calorimetry. The sample preparation and materials processing capabilities in the IASPL have also facilitated experimentation at world-class facilities such as

  4. MARS: bringing the automation of small-molecule bioanalytical sample preparations to a new frontier.

    PubMed

    Li, Ming; Chou, Judy; Jing, Jing; Xu, Hui; Costa, Aldo; Caputo, Robin; Mikkilineni, Rajesh; Flannelly-King, Shane; Rohde, Ellen; Gan, Lawrence; Klunk, Lewis; Yang, Liyu

    2012-06-01

    In recent years, there has been a growing interest in automating small-molecule bioanalytical sample preparations specifically using the Hamilton MicroLab(®) STAR liquid-handling platform. In the most extensive work reported thus far, multiple small-molecule sample preparation assay types (protein precipitation extraction, SPE and liquid-liquid extraction) have been integrated into a suite that is composed of graphical user interfaces and Hamilton scripts. Using that suite, bioanalytical scientists have been able to automate various sample preparation methods to a great extent. However, there are still areas that could benefit from further automation, specifically, the full integration of analytical standard and QC sample preparation with study sample extraction in one continuous run, real-time 2D barcode scanning on the Hamilton deck and direct Laboratory Information Management System database connectivity. We developed a new small-molecule sample-preparation automation system that improves in all of the aforementioned areas. The improved system presented herein further streamlines the bioanalytical workflow, simplifies batch run design, reduces analyst intervention and eliminates sample-handling error.

  5. The Impact of Investments in Additional Preparation on Unified State Exam Results

    ERIC Educational Resources Information Center

    Prakhov, Ilya Arkadyevich

    2015-01-01

    The paper proposes a model of educational strategies for college entrants that makes it possible to assess the investment efficiency in additional preparation as evidenced by the Unified State Exam [USE] scores. It was found that college entrants still use traditional forms of preparation despite the new institutional admission conditions at…

  6. Sample preparation techniques for the determination of trace residues and contaminants in foods.

    PubMed

    Ridgway, Kathy; Lalljie, Sam P D; Smith, Roger M

    2007-06-15

    The determination of trace residues and contaminants in complex matrices, such as food, often requires extensive sample extraction and preparation prior to instrumental analysis. Sample preparation is often the bottleneck in analysis and there is a need to minimise the number of steps to reduce both time and sources of error. There is also a move towards more environmentally friendly techniques, which use less solvent and smaller sample sizes. Smaller sample size becomes important when dealing with real life problems, such as consumer complaints and alleged chemical contamination. Optimal sample preparation can reduce analysis time, sources of error, enhance sensitivity and enable unequivocal identification, confirmation and quantification. This review considers all aspects of sample preparation, covering general extraction techniques, such as Soxhlet and pressurised liquid extraction, microextraction techniques such as liquid phase microextraction (LPME) and more selective techniques, such as solid phase extraction (SPE), solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). The applicability of each technique in food analysis, particularly for the determination of trace organic contaminants in foods is discussed.

  7. Current trends and challenges in sample preparation for metallic nanoparticles analysis in daily products and environmental samples: A review

    NASA Astrophysics Data System (ADS)

    De la Calle, Inmaculada; Menta, Mathieu; Séby, Fabienne

    2016-11-01

    Due to the increasing use of nanoparticles (NPs) in consumer products, it becomes necessary to develop different strategies for their detection, identification, characterization and quantification in a wide variety of samples. Since the analysis of NPs in consumer products and environmental samples is particularly troublesome, a detailed description of challenges and limitations is given here. This review mainly focuses on sample preparation procedures applied for the mostly used techniques for metallic and metal oxide NPs characterization in consumer products and most outstanding publications of biological and environmental samples (from 2006 to 2015). We summarize the procedures applied for total metal content, extraction/separation and/or preconcentration of NPs from the matrix, separation of metallic NPs from their ions or from larger particles and NPs' size fractionation. Sample preparation procedures specifically for microscopy are also described. Selected applications in cosmetics, food, other consumer products, biological tissues and environmental samples are presented. Advantages and inconveniences of those procedures are considered. Moreover, selected simplified schemes for NPs sample preparation, as well as usual techniques applied are included. Finally, promising directions for further investigations are discussed.

  8. Novel sample preparation technique with needle-type micro-extraction device for volatile organic compounds in indoor air samples.

    PubMed

    Ueta, Ikuo; Mizuguchi, Ayako; Fujimura, Koji; Kawakubo, Susumu; Saito, Yoshihiro

    2012-10-09

    A novel needle-type sample preparation device was developed for the effective preconcentration of volatile organic compounds (VOCs) in indoor air before gas chromatography-mass spectrometry (GC-MS) analysis. To develop a device for extracting a wide range of VOCs typically found in indoor air, several types of particulate sorbents were tested as the extraction medium in the needle-type extraction device. To determine the content of these VOCs, air samples were collected for 30min with the packed sorbent(s) in the extraction needle, and the extracted VOCs were thermally desorbed in a GC injection port by the direct insertion of the needle. A double-bed sorbent consisting of a needle packed with divinylbenzene and activated carbon particles exhibited excellent extraction and desorption performance and adequate extraction capacity for all the investigated VOCs. The results also clearly demonstrated that the proposed sample preparation method is a more rapid, simpler extraction/desorption technique than traditional sample preparation methods. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Coleman prepares to insert samples into the MELFI

    NASA Image and Video Library

    2010-12-27

    ISS026-E-023768 (27 Dec. 2010) --- NASA astronaut Catherine (Cady) Coleman, Expedition 26 flight engineer, prepares to insert samples into the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) as part of the Nutritional Status Assessment (NUTRITION) study in the Japanese Kibo laboratory of the International Space Station.

  10. Effort versus Reward: Preparing Samples for Fungal Community Characterization in High-Throughput Sequencing Surveys of Soils

    PubMed Central

    Song, Zewei; Schlatter, Dan; Kennedy, Peter; Kinkel, Linda L.; Kistler, H. Corby; Nguyen, Nhu; Bates, Scott T.

    2015-01-01

    Next generation fungal amplicon sequencing is being used with increasing frequency to study fungal diversity in various ecosystems; however, the influence of sample preparation on the characterization of fungal community is poorly understood. We investigated the effects of four procedural modifications to library preparation for high-throughput sequencing (HTS). The following treatments were considered: 1) the amount of soil used in DNA extraction, 2) the inclusion of additional steps (freeze/thaw cycles, sonication, or hot water bath incubation) in the extraction procedure, 3) the amount of DNA template used in PCR, and 4) the effect of sample pooling, either physically or computationally. Soils from two different ecosystems in Minnesota, USA, one prairie and one forest site, were used to assess the generality of our results. The first three treatments did not significantly influence observed fungal OTU richness or community structure at either site. Physical pooling captured more OTU richness compared to individual samples, but total OTU richness at each site was highest when individual samples were computationally combined. We conclude that standard extraction kit protocols are well optimized for fungal HTS surveys, but because sample pooling can significantly influence OTU richness estimates, it is important to carefully consider the study aims when planning sampling procedures. PMID:25974078

  11. Sample Preparation of Corn Seed Tissue to Prevent Analyte Relocations for Mass Spectrometry Imaging

    NASA Astrophysics Data System (ADS)

    Kim, Shin Hye; Kim, Jeongkwon; Lee, Young Jin; Lee, Tae Geol; Yoon, Sohee

    2017-08-01

    Corn seed tissue sections were prepared by the tape support method using an adhesive tape, and mass spectrometry imaging (MSI) was performed. The effect of heat generated during sample preparation was investigated by time-of-flight secondary mass spectrometry (TOF-SIMS) imaging of corn seed tissue prepared by the tape support and the thaw-mounted methods. Unlike thaw-mounted sample preparation, the tape support method does not cause imaging distortion because of the absence of heat, which can cause migration of the analytes on the sample. By applying the tape-support method, the corn seed tissue was prepared without structural damage and MSI with accurate spatial information of analytes was successfully performed.

  12. 49 CFR 199.111 - Retention of samples and additional testing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2011-10-01 2011-10-01 false Retention of samples and additional testing. 199...

  13. 49 CFR 199.111 - Retention of samples and additional testing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2013-10-01 2013-10-01 false Retention of samples and additional testing. 199...

  14. 49 CFR 199.111 - Retention of samples and additional testing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2012-10-01 2012-10-01 false Retention of samples and additional testing. 199...

  15. 49 CFR 199.111 - Retention of samples and additional testing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2010-10-01 2010-10-01 false Retention of samples and additional testing. 199...

  16. 49 CFR 199.111 - Retention of samples and additional testing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2014-10-01 2014-10-01 false Retention of samples and additional testing. 199...

  17. Dopant mapping in thin FIB prepared silicon samples by Off-Axis Electron Holography.

    PubMed

    Pantzer, Adi; Vakahy, Atsmon; Eliyahou, Zohar; Levi, George; Horvitz, Dror; Kohn, Amit

    2014-03-01

    Modern semiconductor devices function due to accurate dopant distribution. Off-Axis Electron Holography (OAEH) in the transmission electron microscope (TEM) can map quantitatively the electrostatic potential in semiconductors with high spatial resolution. For the microelectronics industry, ongoing reduction of device dimensions, 3D device geometry, and failure analysis of specific devices require preparation of thin TEM samples, under 70 nm thick, by focused ion beam (FIB). Such thicknesses, which are considerably thinner than the values reported to date in the literature, are challenging due to FIB induced damage and surface depletion effects. Here, we report on preparation of TEM samples of silicon PN junctions in the FIB completed by low-energy (5 keV) ion milling, which reduced amorphization of the silicon to 10nm thick. Additional perpendicular FIB sectioning enabled a direct measurement of the TEM sample thickness in order to determine accurately the crystalline thickness of the sample. Consequently, we find that the low-energy milling also resulted in a negligible thickness of electrically inactive regions, approximately 4nm thick. The influence of TEM sample thickness, FIB induced damage and doping concentrations on the accuracy of the OAEH measurements were examined by comparison to secondary ion mass spectrometry measurements as well as to 1D and 3D simulations of the electrostatic potentials. We conclude that for TEM samples down to 100 nm thick, OAEH measurements of Si-based PN junctions, for the doping levels examined here, resulted in quantitative mapping of potential variations, within ~0.1 V. For thinner TEM samples, down to 20 nm thick, mapping of potential variations is qualitative, due to a reduced accuracy of ~0.3 V. This article is dedicated to the memory of Zohar Eliyahou. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Apparatus for preparing a sample for mass spectrometry

    DOEpatents

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed.

  19. Recent developments in sample preparation and data pre-treatment in metabonomics research.

    PubMed

    Li, Ning; Song, Yi peng; Tang, Huiru; Wang, Yulan

    2016-01-01

    Metabonomics is a powerful approach for biomarker discovery and an effective tool for pinpointing endpoint metabolic effects of external stimuli, such as pathogens and disease development. Due to its wide applications, metabonomics is required to deal with various biological samples of different properties. Hence sample preparation and corresponding data pre-treatment become important factors in ensuring validity of an investigation. In this review, we summarize some recent developments in metabonomics sample preparation and data-pretreatment procedures. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Sample preparation and detection device for infectious agents

    DOEpatents

    Miles, Robin R.; Wang, Amy W.; Fuller, Christopher K.; Lemoff, Asuncion V.; Bettencourt, Kerry A.; Yu, June

    2003-06-10

    A sample preparation and analysis device which incorporates both immunoassays and PCR assays in one compact, field-portable microchip. The device provides new capabilities in fluid and particle control which allows the building of a fluidic chip with no moving parts, thus decreasing fabrication cost and increasing the robustness of the device. The device can operate in a true continuous (not batch) mode. The device incorporates magnetohydrodynamic (MHD) pumps to move the fluid through the system, acoustic mixing and fractionation, dielectropheretic (DEP) sample concentration and purification, and on-chip optical detection capabilities.

  1. Apparatus for preparing a sample for mass spectrometry

    DOEpatents

    Villa-Aleman, E.

    1994-05-10

    An apparatus is described for preparing a sample for analysis by a mass spectrometer system. The apparatus has an entry chamber and an ionization chamber separated by a skimmer. A capacitor having two space-apart electrodes followed by one or more ion-imaging lenses is disposed in the ionization chamber. The chamber is evacuated and the capacitor is charged. A valve injects a sample gas in the form of sample pulses into the entry chamber. The pulse is collimated by the skimmer and enters the ionization chamber. When the sample pulse passes through the gap between the electrodes, it discharges the capacitor and is thereby ionized. The ions are focused by the imaging lenses and enter the mass analyzer, where their mass and charge are analyzed. 1 figures.

  2. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic...

  3. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic...

  4. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic...

  5. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Procedures for preparing egg yolk samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic...

  6. High-resolution X-ray diffraction with no sample preparation

    PubMed Central

    Turner, S. M. R.; Degryse, P.; Shortland, A. J.

    2017-01-01

    It is shown that energy-dispersive X-ray diffraction (EDXRD) implemented in a back-reflection geometry is extremely insensitive to sample morphology and positioning even in a high-resolution configuration. This technique allows high-quality X-ray diffraction analysis of samples that have not been prepared and is therefore completely non-destructive. The experimental technique was implemented on beamline B18 at the Diamond Light Source synchrotron in Oxfordshire, UK. The majority of the experiments in this study were performed with pre-characterized geological materials in order to elucidate the characteristics of this novel technique and to develop the analysis methods. Results are presented that demonstrate phase identification, the derivation of precise unit-cell parameters and extraction of microstructural information on unprepared rock samples and other sample types. A particular highlight was the identification of a specific polytype of a muscovite in an unprepared mica schist sample, avoiding the time-consuming and difficult preparation steps normally required to make this type of identification. The technique was also demonstrated in application to a small number of fossil and archaeological samples. Back-reflection EDXRD implemented in a high-resolution configuration shows great potential in the crystallographic analysis of cultural heritage artefacts for the purposes of scientific research such as provenancing, as well as contributing to the formulation of conservation strategies. Possibilities for moving the technique from the synchrotron into museums are discussed. The avoidance of the need to extract samples from high-value and rare objects is a highly significant advantage, applicable also in other potential research areas such as palaeontology, and the study of meteorites and planetary materials brought to Earth by sample-return missions. PMID:28660862

  7. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... establish a surface concentration to be included in the standard operating procedure. The surface levels of... Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to... surfaces must be ≥20 µg/100 cm2. (2) To validate a procedure to decontaminate a specified surface...

  8. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... establish a surface concentration to be included in the standard operating procedure. The surface levels of... Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to... surfaces must be ≥20 µg/100 cm2. (2) To validate a procedure to decontaminate a specified surface...

  9. 40 CFR 761.392 - Preparing validation study samples.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... establish a surface concentration to be included in the standard operating procedure. The surface levels of... Under § 761.79(d)(4) § 761.392 Preparing validation study samples. (a)(1) To validate a procedure to... surfaces must be ≥20 µg/100 cm2. (2) To validate a procedure to decontaminate a specified surface...

  10. Advanced Curation Preparation for Mars Sample Return and Cold Curation

    NASA Technical Reports Server (NTRS)

    Fries, M. D.; Harrington, A. D.; McCubbin, F. M.; Mitchell, J.; Regberg, A. B.; Snead, C.

    2017-01-01

    NASA Curation is tasked with the care and distribution of NASA's sample collections, such as the Apollo lunar samples and cometary material collected by the Stardust spacecraft. Curation is also mandated to perform Advanced Curation research and development, which includes improving the curation of existing collections as well as preparing for future sample return missions. Advanced Curation has identified a suite of technologies and techniques that will require attention ahead of Mars sample return (MSR) and missions with cold curation (CCur) requirements, perhaps including comet sample return missions.

  11. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR

    PubMed Central

    Mandal, Abhishek; Boatz, Jennifer C.; Wheeler, Travis; van der Wel, Patrick C. A.

    2017-01-01

    A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation. PMID:28229262

  12. Cross-sectional TEM specimen preparation for W/B{sub 4}C multilayer sample using FIB

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mondal, Puspen, E-mail: puspen@rrcat.gov.in; Pradhan, P. C.; Tiwari, Pragya

    2016-05-23

    A recent emergence of a cross-beam scanning electron microscopy (SEM)/focused-ion-beam (FIB) system have given choice to fabricate cross-sectional transmission electron microscopy (TEM) specimen of thin film multilayer sample. A 300 layer pair thin film multilayer sample of W/B{sub 4}C was used to demonstrate the specimen lift-out technique in very short time as compared to conventional cross-sectional sample preparation technique. To get large area electron transparent sample, sample prepared by FIB is followed by Ar{sup +} ion polishing at 2 kV with grazing incident. The prepared cross-sectional sample was characterized by transmission electron microscope.

  13. Miniaturized sample preparation needle: a versatile design for the rapid analysis of smoking-related compounds in hair and air samples.

    PubMed

    Saito, Yoshihiro; Ueta, Ikuo; Ogawa, Mitsuhiro; Hayashida, Makiko; Jinno, Kiyokatsu

    2007-05-09

    Miniaturized needle extraction device has been developed as a versatile sample preparation device designed for the rapid and simple analysis of smoking-related compounds in smokers' hair samples and environmental tobacco smoke. Packed with polymeric particle, the resulting particle-packed needle was employed as a miniaturized sample preparation device for the analysis of typical volatile organic compounds in tobacco smoke. Introducing a bundle of polymer-coated filaments as the extraction medium, the needle was further applied as a novel sample preparation device containing simultaneous derivatization/extraction process of volatile aldehydes. Formaldehyde (FA) and acetaldehyde (AA) in smoker's breath during the smoking were successfully derivatized with two derivatization reagents in the polymer-coated fiber-packed needle device followed by the separation and determination in gas chromatography (GC). Smokers' hair samples were also packed into the needle, allowing the direct extraction of nicotine from the hair sample in a conventional GC injector. Optimizing the main experimental parameters for each technique, successful determination of several smoking-related compounds with these needle extraction methods has been demonstrated.

  14. Sample preparation and liquid chromatography-tandem mass spectrometry for multiple steroids in mammalian and avian circulation.

    PubMed

    Koren, Lee; Ng, Ella S M; Soma, Kiran K; Wynne-Edwards, Katherine E

    2012-01-01

    Blood samples from wild mammals and birds are often limited in volume, allowing researchers to quantify only one or two steroids from a single sample by immunoassays. In addition, wildlife serum or plasma samples are often lipemic, necessitating stringent sample preparation. Here, we validated sample preparation for simultaneous liquid chromatography--tandem mass spectrometry (LC-MS/MS) quantitation of cortisol, corticosterone, 11-deoxycortisol, dehydroepiandrosterone (DHEA), 17β-estradiol, progesterone, 17α-hydroxyprogesterone and testosterone from diverse mammalian (7 species) and avian (5 species) samples. Using 100 µL of serum or plasma, we quantified (signal-to-noise (S/N) ratio ≥ 10) 4-7 steroids depending on the species and sample, without derivatization. Steroids were extracted from serum or plasma using automated solid-phase extraction where samples were loaded onto C18 columns, washed with water and hexane, and then eluted with ethyl acetate. Quantitation by LC-MS/MS was done in positive ion, multiple reaction-monitoring (MRM) mode with an atmospheric pressure chemical ionization (APCI) source and heated nebulizer (500°C). Deuterated steroids served as internal standards and run time was 15 minutes. Extraction recoveries were 87-101% for the 8 analytes, and all intra- and inter-run CVs were ≤ 8.25%. This quantitation method yields good recoveries with variable lipid-content samples, avoids antibody cross-reactivity issues, and delivers results for multiple steroids. Thus, this method can enrich datasets by providing simultaneous quantitation of multiple steroids, and allow researchers to reimagine the hypotheses that could be tested with their volume-limited, lipemic, wildlife samples.

  15. An apparatus for preparing benthic samples aboard ship

    USGS Publications Warehouse

    Pepper, Phillip N.; Girard, Thomas L.; Stapanian, Martin A.

    2001-01-01

    We describe a safe and effective apparatus for washing and reducing the volume of benthic samples collected by grab samplers aboard ship. The sample is transferred directly from the dredge to the apparatus and then washed with water pumped through pipes in the apparatus and from onboard hoses. Wastewater and materials smaller than 0.541 mm in diameter are washed overboard. Larger materials, including benthic organisms, collect on an upper 0.64-cm screen and on a lower 30-mm-mesh stainless steel bolt cloth. A collection jar is screwed into the bottom of the apparatus. Therefore, transfer of sample material from the apparatus to the jar is quick and easy. This apparatus has several advantages for use aboard ship over others described in the literature, especially in rough seas, in cold weather, and at night. The apparatus provides a safe and convenient platform for washing and reducing samples, and samples can be prepared while the vessel is traveling at full speed.

  16. Automated cellular sample preparation using a Centrifuge-on-a-Chip.

    PubMed

    Mach, Albert J; Kim, Jae Hyun; Arshi, Armin; Hur, Soojung Claire; Di Carlo, Dino

    2011-09-07

    The standard centrifuge is a laboratory instrument widely used by biologists and medical technicians for preparing cell samples. Efforts to automate the operations of concentration, cell separation, and solution exchange that a centrifuge performs in a simpler and smaller platform have had limited success. Here, we present a microfluidic chip that replicates the functions of a centrifuge without moving parts or external forces. The device operates using a purely fluid dynamic phenomenon in which cells selectively enter and are maintained in microscale vortices. Continuous and sequential operation allows enrichment of cancer cells from spiked blood samples at the mL min(-1) scale, followed by fluorescent labeling of intra- and extra-cellular antigens on the cells without the need for manual pipetting and washing steps. A versatile centrifuge-analogue may open opportunities in automated, low-cost and high-throughput sample preparation as an alternative to the standard benchtop centrifuge in standardized clinical diagnostics or resource poor settings.

  17. Visualizing preparation using asymmetrical choline-like ionic liquids for scanning electron microscope observation of non-conductive biological samples.

    PubMed

    Abe, Shigeaki; Hyono, Atsushi; Kawai, Koji; Yonezawa, Tetsu

    2014-03-01

    In this study, we investigated conductivity preparation for scanning electron microscope (SEM) observation that used novel asymmetrical choline-type room temperature ionic liquids (RTIL). By immersion in only an RTIL solution, clear SEM images of several types of biological samples were successfully observed. In addition, we could visualize protozoans using RTILs without any dilution. These results suggested that the asymmetrical choline-type RTILs used in this study are suitable for visualizing of biological samples by SEM. Treatment without the need for dilution can obviate the need for adjusting the RTIL concentration and provide for a rapid and easy conductivity treatment for insulating samples.

  18. Ionic liquids: solvents and sorbents in sample preparation.

    PubMed

    Clark, Kevin D; Emaus, Miranda N; Varona, Marcelino; Bowers, Ashley N; Anderson, Jared L

    2018-01-01

    The applications of ionic liquids (ILs) and IL-derived sorbents are rapidly expanding. By careful selection of the cation and anion components, the physicochemical properties of ILs can be altered to meet the requirements of specific applications. Reports of IL solvents possessing high selectivity for specific analytes are numerous and continue to motivate the development of new IL-based sample preparation methods that are faster, more selective, and environmentally benign compared to conventional organic solvents. The advantages of ILs have also been exploited in solid/polymer formats in which ordinarily nonspecific sorbents are functionalized with IL moieties in order to impart selectivity for an analyte or analyte class. Furthermore, new ILs that incorporate a paramagnetic component into the IL structure, known as magnetic ionic liquids (MILs), have emerged as useful solvents for bioanalytical applications. In this rapidly changing field, this Review focuses on the applications of ILs and IL-based sorbents in sample preparation with a special emphasis on liquid phase extraction techniques using ILs and MILs, IL-based solid-phase extraction, ILs in mass spectrometry, and biological applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Humidity-controlled preparation of frozen-hydrated biological samples for cryogenic coherent x-ray diffraction microscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Takayama, Yuki; Nakasako, Masayoshi; RIKEN Harima Institute/SPring-8, 1-1-1 Kouto, Mikaduki, Sayo, Hyogo 679-5148

    2012-05-15

    Coherent x-ray diffraction microscopy (CXDM) has the potential to visualize the structures of micro- to sub-micrometer-sized biological particles, such as cells and organelles, at high resolution. Toward advancing structural studies on the functional states of such particles, here, we developed a system for the preparation of frozen-hydrated biological samples for cryogenic CXDM experiments. The system, which comprised a moist air generator, microscope, micro-injector mounted on a micromanipulator, custom-made sample preparation chamber, and flash-cooling device, allowed for the manipulation of sample particles in the relative humidity range of 20%-94%rh at 293 K to maintain their hydrated and functional states. Here, wemore » report the details of the system and the operation procedure, including its application to the preparation of a frozen-hydrated chloroplast sample. Sample quality was evaluated through a cryogenic CXDM experiment conducted at BL29XUL of SPring-8. Taking the performance of the system and the quality of the sample, the system was suitable to prepare frozen-hydrated biological samples for cryogenic CXDM experiments.« less

  20. EVALUATION OF ARG-1 SAMPLES PREPARED BY CESIUM CARBONATE DISSOLUTION DURING THE ISOLOK SME ACCEPTABILITY TESTING

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Edwards, T.; Hera, K.; Coleman, C.

    2011-12-05

    Evaluation of Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) recently completed the evaluation of one of these opportunities - the possibility of using an Isolok sampling valve as an alternative to the Hydragard valve for taking DWPF process samples at the Slurry Mix Evaporator (SME). The use of an Isolok for SME sampling has the potential to improve operability, reduce maintenance time, and decrease CPC cycle time. The SME acceptability testingmore » for the Isolok was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 and was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNLRP-2011-00145. RW-0333P QA requirements applied to the task, and the results from the investigation were documented in SRNL-STI-2011-00693. Measurement of the chemical composition of study samples was a critical component of the SME acceptability testing of the Isolok. A sampling and analytical plan supported the investigation with the analytical plan directing that the study samples be prepared by a cesium carbonate (Cs{sub 2}CO{sub 3}) fusion dissolution method and analyzed by Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). The use of the cesium carbonate preparation method for the Isolok testing provided an opportunity for an additional assessment of this dissolution method, which is being investigated as a potential replacement for the two methods (i.e., sodium peroxide fusion and mixed acid dissolution) that have been used at the DWPF for the analysis of SME samples. Earlier testing of the Cs{sub 2}CO{sub 3} method yielded promising results which led to a TTR from Savannah River Remediation, LLC (SRR) to SRNL for additional support and an associated TTQAP to direct the SRNL efforts. A technical report

  1. Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

    DOE PAGES

    Adamic, M. L.; Lister, T. E.; Dufek, E. J.; ...

    2015-03-25

    This paper presents an evaluation of an alternate method for preparing environmental samples for 129I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Furthermore, precipitated silver iodide samples are usually mixed with niobium or silver powdermore » prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.« less

  2. Time of flight secondary ion mass spectrometry of bone—Impact of sample preparation and measurement conditions

    PubMed Central

    Henss, Anja; Hild, Anne; Rohnke, Marcus; Wenisch, Sabine; Janek, Juergen

    2015-01-01

    Time of flight secondary ion mass spectrometry (ToF-SIMS) enables the simultaneous detection of organic and inorganic ions and fragments with high mass and spatial resolution. Due to recent technical developments, ToF-SIMS has been increasingly applied in the life sciences where sample preparation plays an eminent role for the quality of the analytical results. This paper focusses on sample preparation of bone tissue and its impact on ToF-SIMS analysis. The analysis of bone is important for the understanding of bone diseases and the development of replacement materials and new drugs for the cure of diseased bone. The main purpose of this paper is to find out which preparation process is best suited for ToF-SIMS analysis of bone tissue in order to obtain reliable and reproducible analytical results. The influence of the embedding process on the different components of bone is evaluated using principal component analysis. It is shown that epoxy resin as well as methacrylate based plastics (Epon and Technovit) as embedding materials do not infiltrate the mineralized tissue and that cut sections are better suited for the ToF-SIMS analysis than ground sections. In case of ground samples, a resin layer is smeared over the sample surface due to the polishing step and overlap of peaks is found. Beside some signals of fatty acids in the negative ion mode, the analysis of native, not embedded samples does not provide any advantage. The influence of bismuth bombardment and O2 flooding on the signal intensity of organic and inorganic fragments due to the variation of the ionization probability is additionally discussed. As C60 sputtering has to be applied to remove the smeared resin layer, its effect especially on the organic fragments of the bone is analyzed and described herein. PMID:26253108

  3. Time of flight secondary ion mass spectrometry of bone-Impact of sample preparation and measurement conditions.

    PubMed

    Henss, Anja; Hild, Anne; Rohnke, Marcus; Wenisch, Sabine; Janek, Juergen

    2015-06-07

    Time of flight secondary ion mass spectrometry (ToF-SIMS) enables the simultaneous detection of organic and inorganic ions and fragments with high mass and spatial resolution. Due to recent technical developments, ToF-SIMS has been increasingly applied in the life sciences where sample preparation plays an eminent role for the quality of the analytical results. This paper focusses on sample preparation of bone tissue and its impact on ToF-SIMS analysis. The analysis of bone is important for the understanding of bone diseases and the development of replacement materials and new drugs for the cure of diseased bone. The main purpose of this paper is to find out which preparation process is best suited for ToF-SIMS analysis of bone tissue in order to obtain reliable and reproducible analytical results. The influence of the embedding process on the different components of bone is evaluated using principal component analysis. It is shown that epoxy resin as well as methacrylate based plastics (Epon and Technovit) as embedding materials do not infiltrate the mineralized tissue and that cut sections are better suited for the ToF-SIMS analysis than ground sections. In case of ground samples, a resin layer is smeared over the sample surface due to the polishing step and overlap of peaks is found. Beside some signals of fatty acids in the negative ion mode, the analysis of native, not embedded samples does not provide any advantage. The influence of bismuth bombardment and O2 flooding on the signal intensity of organic and inorganic fragments due to the variation of the ionization probability is additionally discussed. As C60 sputtering has to be applied to remove the smeared resin layer, its effect especially on the organic fragments of the bone is analyzed and described herein.

  4. Importance of sample preparation for molecular diagnosis of lyme borreliosis from urine.

    PubMed

    Bergmann, A R; Schmidt, B L; Derler, A-M; Aberer, E

    2002-12-01

    Urine PCR has been used for the diagnosis of Borrelia burgdorferi infection in recent years but has been abandoned because of its low sensitivity and the irreproducibility of the results. Our study aimed to analyze technical details related to sample preparation and detection methods. Crucial for a successful urine PCR were (i) avoidance of the first morning urine sample; (ii) centrifugation at 36,000 x g; and (iii) the extraction method, with only DNAzol of the seven different extraction methods used yielding positive results with patient urine specimens. Furthermore, storage of frozen urine samples at -80 degrees C reduced the sensitivity of a positive urine PCR result obtained with samples from 72 untreated erythema migrans (EM) patients from 85% in the first 3 months to <30% after more than 3 months. Bands were detected at 276 bp on ethidium bromide-stained agarose gels after amplification by a nested PCR. The specificity of bands for 32 of 33 samples was proven by hybridization with a GEN-ETI-K-DEIA kit and for a 10 further positive amplicons by sequencing. By using all of these steps to optimize the urine PCR technique, B. burgdorferi infection could be diagnosed by using urine samples from EM patients with a sensitivity (85%) substantially better than that of serological methods (50%). This improved method could be of future importance as an additional laboratory technique for the diagnosis of unclear, unrecognized borrelia infections and diseases possibly related to Lyme borreliosis.

  5. Sample preparation for thermo-gravimetric determination and thermo-gravimetric characterization of refuse derived fuel.

    PubMed

    Robinson, T; Bronson, B; Gogolek, P; Mehrani, P

    2016-02-01

    Thermo-gravimetric analysis (TGA) is a useful method for characterizing fuels. In the past it has been applied to the study of refuse derived fuel (RDF) and related materials. However, the heterogeneity of RDF makes the preparation of small representative samples very difficult and this difficulty has limited the effectiveness of TGA for characterization of RDF. A TGA method was applied to a variety of materials prepared from a commercially available RDF using a variety of procedures. Applicability of TGA method to the determination of the renewable content of RDF was considered. Cryogenic ball milling was found to be an effective means of preparing RDF samples for TGA. When combined with an effective sample preparation, TGA could be used as an alternative method for assessing the renewable content of RDF. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  6. Sample preparation for the analysis of isoflavones from soybeans and soy foods.

    PubMed

    Rostagno, M A; Villares, A; Guillamón, E; García-Lafuente, A; Martínez, J A

    2009-01-02

    This manuscript provides a review of the actual state and the most recent advances as well as current trends and future prospects in sample preparation and analysis for the quantification of isoflavones from soybeans and soy foods. Individual steps of the procedures used in sample preparation, including sample conservation, extraction techniques and methods, and post-extraction treatment procedures are discussed. The most commonly used methods for extraction of isoflavones with both conventional and "modern" techniques are examined in detail. These modern techniques include ultrasound-assisted extraction, pressurized liquid extraction, supercritical fluid extraction and microwave-assisted extraction. Other aspects such as stability during extraction and analysis by high performance liquid chromatography are also covered.

  7. Influence of sample preparation on the transformation of low-density to high-density amorphous ice: An explanation based on the potential energy landscape

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Starr, Francis W.; Poole, Peter H.

    2017-07-01

    Experiments and computer simulations of the transformations of amorphous ices display different behaviors depending on sample preparation methods and on the rates of change of temperature and pressure to which samples are subjected. In addition to these factors, simulation results also depend strongly on the chosen water model. Using computer simulations of the ST2 water model, we study how the sharpness of the compression-induced transition from low-density amorphous ice (LDA) to high-density amorphous ice (HDA) is influenced by the preparation of LDA. By studying LDA samples prepared using widely different procedures, we find that the sharpness of the LDA-to-HDA transformation is correlated with the depth of the initial LDA sample in the potential energy landscape (PEL), as characterized by the inherent structure energy. Our results show that the complex phenomenology of the amorphous ices reported in experiments and computer simulations can be understood and predicted in a unified way from knowledge of the PEL of the system.

  8. 40 CFR 205.171-2 - Test exhaust system sample selection and preparation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Test exhaust system sample selection... Systems § 205.171-2 Test exhaust system sample selection and preparation. (a)(1) Exhaust systems comprising the sample which are required to be tested under a test request in accordance with this subpart...

  9. TruSeq Stranded mRNA and Total RNA Sample Preparation Kits

    Cancer.gov

    Total RNA-Seq enabled by ribosomal RNA (rRNA) reduction is compatible with formalin-fixed paraffin embedded (FFPE) samples, which contain potentially critical biological information. The family of TruSeq Stranded Total RNA sample preparation kits provides a unique combination of unmatched data quality for both mRNA and whole-transcriptome analyses, robust interrogation of both standard and low-quality samples and workflows compatible with a wide range of study designs.

  10. Modified Sample Preparation Approach for the Determination of the Phenolic and Humic-Like Substances in Natural Organic Materials By the Folin Ciocalteu Method.

    PubMed

    Pontoni, Ludovico; Panico, Antonio; Matanò, Alessia; van Hullebusch, Eric D; Fabbricino, Massimiliano; Esposito, Giovanni; Pirozzi, Francesco

    2017-12-06

    A novel modification of the sample preparation procedure for the Folin-Ciocalteu colorimetric assay for the determination of total phenolic compounds in natural solid and semisolid organic materials (e.g., foods, organic solid waste, soils, plant tissues, agricultural residues, manure) is proposed. In this method, the sample is prepared by adding sodium sulfate as a solid diluting agent before homogenization. The method allows for the determination of total phenols (TP) in samples with high solids contents, and it provides good accuracy and reproducibility. Additionally, this method permits analyses of significant amounts of sample, which reduces problems related to heterogeneity. We applied this method to phenols-rich lignocellulosic and humic-like solids and semisolid samples, including rice straw (RS), peat-rich soil (PS), and food waste (FW). The TP concentrations measured with the solid dilution (SD) preparation were substantially higher (increases of 41.4%, 15.5%, and 59.4% in RS, PS and FW, respectively) than those obtained with the traditional method (solids suspended in water). These results showed that the traditional method underestimates the phenolic contents in the studied solids.

  11. Effect of Sn addition on glassy Si-Te bulk sample

    NASA Astrophysics Data System (ADS)

    Babanna, Jagannatha K.; Roy, Diptoshi; Varma, Sreevidya G.; Asokan, Sundarrajan; Das, Chandasree

    2018-05-01

    Bulk Si20Te79Sn1 glass is prepared by melt-quenching method, amorphous nature of the as-quenched glass is confirmed by XRD. I-V characteristics reveals that Si20Te79Sn1 bulk sample exhibits threshold type electrical switching behavior. The thermal parameters such as crystallization temperature, glass transition temperature are obtained using differential scanning calorimetry. The crystalline peak study of the sample annealed at crystallization temperature for 2 hr shows that the Sn atom interact with Si or Te but do not interact with the Si-Te matrix in a greater extent and it forms a separate phase network individually.

  12. Basic tree-ring sample preparation techniques for aging aspen

    Treesearch

    Lance A. Asherin; Stephen A. Mata

    2001-01-01

    Aspen is notoriously difficult to age because of its light-colored wood and faint annual growth rings. Careful preparation and processing of aspen ring samples can overcome these problems, yield accurate age and growth estimates, and concisely date disturbance events present in the tree-ring record. Proper collection of aspen wood is essential in obtaining usable ring...

  13. Preparation of pure microbiological samples for pyrolysis gas-liquid chromatography studies

    NASA Technical Reports Server (NTRS)

    Oxborrow, G. S.; Fields, N. D.; Puleo, J. R.

    1976-01-01

    Bacterial samples were prepared for pyrolysis gas-liquid chromatography using cells grown on membrane filters. Pyrochromatograms were reproducible when cells harvested from the filters were pyrolyzed without being washed.

  14. Microfluidic devices for sample preparation and rapid detection of foodborne pathogens.

    PubMed

    Kant, Krishna; Shahbazi, Mohammad-Ali; Dave, Vivek Priy; Ngo, Tien Anh; Chidambara, Vinayaka Aaydha; Than, Linh Quyen; Bang, Dang Duong; Wolff, Anders

    2018-03-10

    Rapid detection of foodborne pathogens at an early stage is imperative for preventing the outbreak of foodborne diseases, known as serious threats to human health. Conventional bacterial culturing methods for foodborne pathogen detection are time consuming, laborious, and with poor pathogen diagnosis competences. This has prompted researchers to call the current status of detection approaches into question and leverage new technologies for superior pathogen sensing outcomes. Novel strategies mainly rely on incorporating all the steps from sample preparation to detection in miniaturized devices for online monitoring of pathogens with high accuracy and sensitivity in a time-saving and cost effective manner. Lab on chip is a blooming area in diagnosis, which exploits different mechanical and biological techniques to detect very low concentrations of pathogens in food samples. This is achieved through streamlining the sample handling and concentrating procedures, which will subsequently reduce human errors and enhance the accuracy of the sensing methods. Integration of sample preparation techniques into these devices can effectively minimize the impact of complex food matrix on pathogen diagnosis and improve the limit of detections. Integration of pathogen capturing bio-receptors on microfluidic devices is a crucial step, which can facilitate recognition abilities in harsh chemical and physical conditions, offering a great commercial benefit to the food-manufacturing sector. This article reviews recent advances in current state-of-the-art of sample preparation and concentration from food matrices with focus on bacterial capturing methods and sensing technologies, along with their advantages and limitations when integrated into microfluidic devices for online rapid detection of pathogens in foods and food production line. Copyright © 2018. Published by Elsevier Inc.

  15. Investigation of solvent-free MALDI-TOFMS sample preparation methods for the analysis of organometallic and coordination compounds.

    PubMed

    Hughes, Laura; Wyatt, Mark F; Stein, Bridget K; Brenton, A Gareth

    2009-01-15

    An investigation of various solvent-free matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) sample preparation methods for the characterization of organometallic and coordination compounds is described. Such methods are desirable for insoluble materials, compounds that are only soluble in disadvantageous solvents, or complexes that dissociate in solution, all of which present a major "difficulty" to most mass spectrometry techniques. First-row transition metal acetylacetonate complexes, which have been characterized previously by solution preparation MALDI-TOFMS, were used to evaluate the various solvent-free procedures. These procedures comprise two distinct steps: the first being the efficient "solids mixing" (the mixing of sample and matrix), and the second being the effective transfer of the sample/matrix mixture to the MALDI target plate. This investigation shows that vortex mixing is the most efficient first step and that smearing using a microspatula is the most effective second step. In addition, the second step is shown to be much more critical than the first step in obtaining high-quality data. Case studies of truly insoluble materials highlight the importance of these techniques for the wider chemistry community.

  16. Protocols for the analytical characterization of therapeutic monoclonal antibodies. II - Enzymatic and chemical sample preparation.

    PubMed

    Bobaly, Balazs; D'Atri, Valentina; Goyon, Alexandre; Colas, Olivier; Beck, Alain; Fekete, Szabolcs; Guillarme, Davy

    2017-08-15

    The analytical characterization of therapeutic monoclonal antibodies and related proteins usually incorporates various sample preparation methodologies. Indeed, quantitative and qualitative information can be enhanced by simplifying the sample, thanks to the removal of sources of heterogeneity (e.g. N-glycans) and/or by decreasing the molecular size of the tested protein by enzymatic or chemical fragmentation. These approaches make the sample more suitable for chromatographic and mass spectrometric analysis. Structural elucidation and quality control (QC) analysis of biopharmaceutics are usually performed at intact, subunit and peptide levels. In this paper, general sample preparation approaches used to attain peptide, subunit and glycan level analysis are overviewed. Protocols are described to perform tryptic proteolysis, IdeS and papain digestion, reduction as well as deglycosylation by PNGase F and EndoS2 enzymes. Both historical and modern sample preparation methods were compared and evaluated using rituximab and trastuzumab, two reference therapeutic mAb products approved by Food and Drug Administration (FDA) and European Medicines Agency (EMA). The described protocols may help analysts to develop sample preparation methods in the field of therapeutic protein analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. [Standard sample preparation method for quick determination of trace elements in plastic].

    PubMed

    Yao, Wen-Qing; Zong, Rui-Long; Zhu, Yong-Fa

    2011-08-01

    Reference sample was prepared by masterbatch method, containing heavy metals with known concentration of electronic information products (plastic), the repeatability and precision were determined, and reference sample preparation procedures were established. X-Ray fluorescence spectroscopy (XRF) analysis method was used to determine the repeatability and uncertainty in the analysis of the sample of heavy metals and bromine element. The working curve and the metrical methods for the reference sample were carried out. The results showed that the use of the method in the 200-2000 mg x kg(-1) concentration range for Hg, Pb, Cr and Br elements, and in the 20-200 mg x kg(-1) range for Cd elements, exhibited a very good linear relationship, and the repeatability of analysis methods for six times is good. In testing the circuit board ICB288G and ICB288 from the Mitsubishi Heavy Industry Company, results agreed with the recommended values.

  18. Cytotoxicity of Light-Cured Dental Materials according to Different Sample Preparation Methods

    PubMed Central

    Lee, Myung-Jin; Kim, Mi-Joo; Kwon, Jae-Sung; Lee, Sang-Bae; Kim, Kwang-Mahn

    2017-01-01

    Dental light-cured resins can undergo different degrees of polymerization when applied in vivo. When polymerization is incomplete, toxic monomers may be released into the oral cavity. The present study assessed the cytotoxicity of different materials, using sample preparation methods that mirror clinical conditions. Composite and bonding resins were used and divided into four groups according to sample preparation method: uncured; directly cured samples, which were cured after being placed on solidified agar; post-cured samples were polymerized before being placed on agar; and “removed unreacted layer” samples had their oxygen-inhibition layer removed after polymerization. Cytotoxicity was evaluated using an agar diffusion test, MTT assay, and confocal microscopy. Uncured samples were the most cytotoxic, while removed unreacted layer samples were the least cytotoxic (p < 0.05). In the MTT assay, cell viability increased significantly in every group as the concentration of the extracts decreased (p < 0.05). Extracts from post-cured and removed unreacted layer samples of bonding resin were less toxic than post-cured and removed unreacted layer samples of composite resin. Removal of the oxygen-inhibition layer resulted in the lowest cytotoxicity. Clinicians should remove unreacted monomers on the resin surface immediately after restoring teeth with light-curing resin to improve the restoration biocompatibility. PMID:28772647

  19. Investigating a Drop-on-Demand Microdispenser for Standardized Sample Preparation

    DTIC Science & Technology

    2012-09-01

    Demand Microdispenser for Standardized Sample Preparation Ellen L. Holthoff, Mikella E. Farrell, and Paul M. Pellegrino Sensors and Electron Devices...instrument. The use of a gravimetric method, such as a quartz crystal microbalance4 ( QCM ) or a sensitive microbalance as discussed in this report, is

  20. Preparation of graphene thin films for radioactive samples.

    PubMed

    Roteta, Miguel; Fernández-Martínez, Rodolfo; Mejuto, Marcos; Rucandio, Isabel

    2016-03-01

    A new method for the preparation of conductive thin films is presented. The metallization of VYNS films guarantees the electrical conductivity but it results in the breaking of a high proportion of them. Graphene, a two-dimensional nanostructure of monolayer or few layers graphite has attracted a great deal of attention because of its excellent properties such as a good chemical stability, mechanical resistance and extraordinary electronic transport properties. In this work, the possibilities of graphene have been explored as a way to produce electrical conductive thin films without an extra metallization process. The procedure starts with preparing homogenous suspensions of reduced graphene oxide (rGO) in conventional VYNS solutions. Ultra-sonication is used to ensure a good dispersibility of rGO. Graphene oxide (GO) is prepared via oxidation of graphite and subsequent exfoliation by sonication. Different chemically rGO were obtained by reaction with hydrazine sulfate, sodium borohydride, ascorbic acid and hydroiodic acid as reducing agents. The preparation of the thin graphene films is done in a similar way as the conventional VYNS foil preparation procedure. Drops of the solution are deposited onto water. The graphene films have been used to prepare sources containing some electron capture radionuclides ((109)Cd, (55)Fe, (139)Ce) with an activity in the order of 3kBq. The samples have been measured to test the attainable low energy electron efficiency and the energy resolution of Auger and conversion electrons by 4π (electron capture)-γ coincidence measurements. The 4π (electron capture)-γ coincidence setup includes a pressurized proportional counter and a NaI(Tl) detector. Tests with different pressures up to 1000kPa were carried out. All these tests show similar values in both parameters (efficiency and resolution) as those obtained by using the conventional metallized films without the drawback of the high percentage of broken films. Copyright © 2015

  1. Hadfield prepares to insert biological samples in the MELFI-1

    NASA Image and Video Library

    2013-01-07

    View of Canadian Space Agency (CSA) Chris Hadfield,Expedition 34 Flight Engineer (FE),preparing to insert biological samples in the Minus Eighty Laboratory Freezer for International Space Station (ISS) - (MELFI-1),in the Japanese Experiment Module (JEM) Pressurized Module (JPM). Photo was taken during Expedition 34.

  2. Sample preparation: a critical step in the analysis of cholesterol oxidation products.

    PubMed

    Georgiou, Christiana A; Constantinou, Michalis S; Kapnissi-Christodoulou, Constantina P

    2014-02-15

    In recent years, cholesterol oxidation products (COPs) have drawn scientific interest, particularly due to their implications on human health. A big number of these compounds have been demonstrated to be cytotoxic, mutagenic, and carcinogenic. The main source of COPs is through diet, and particularly from the consumption of cholesterol-rich foods. This raises questions about the safety of consumers, and it suggests the necessity for the development of a sensitive and a reliable analytical method in order to identify and quantify these components in food samples. Sample preparation is a necessary step in the analysis of COPs in order to eliminate interferences and increase sensitivity. Numerous publications have, over the years, reported the use of different methods for the extraction and purification of COPs. However, no method has, so far, been established as a routine method for the analysis of COPs in foods. Therefore, it was considered important to overview different sample preparation procedures and evaluate the different preparative parameters, such as time of saponification, the type of organic solvents for fat extraction, the stationary phase in solid phase extraction, etc., according to recovery, precision and simplicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Spectral reproducibility and quantification of peptides in MALDI of samples prepared by micro-spotting.

    PubMed

    Bae, Yong Jin; Park, Kyung Man; Ahn, Sung Hee; Moon, Jeong Hee; Kim, Myung Soo

    2014-08-01

    Previously, we reported that MALDI spectra of peptides became reproducible when temperature was kept constant. Linear calibration curves derived from such spectral data could be used for quantification. Homogeneity of samples was one of the requirements. Among the three popular matrices used in peptide MALDI [i.e., α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (DHB), and sinapinic acid (SA)], homogeneous samples could be prepared by conventional means only for CHCA. In this work, we showed that sample preparation by micro-spotting improved the homogeneity for all three cases.

  4. An automation-assisted generic approach for biological sample preparation and LC-MS/MS method validation.

    PubMed

    Zhang, Jie; Wei, Shimin; Ayres, David W; Smith, Harold T; Tse, Francis L S

    2011-09-01

    Although it is well known that automation can provide significant improvement in the efficiency of biological sample preparation in quantitative LC-MS/MS analysis, it has not been widely implemented in bioanalytical laboratories throughout the industry. This can be attributed to the lack of a sound strategy and practical procedures in working with robotic liquid-handling systems. Several comprehensive automation assisted procedures for biological sample preparation and method validation were developed and qualified using two types of Hamilton Microlab liquid-handling robots. The procedures developed were generic, user-friendly and covered the majority of steps involved in routine sample preparation and method validation. Generic automation procedures were established as a practical approach to widely implement automation into the routine bioanalysis of samples in support of drug-development programs.

  5. A 96-well screen filter plate for high-throughput biological sample preparation and LC-MS/MS analysis.

    PubMed

    Peng, Sean X; Cousineau, Martin; Juzwin, Stephen J; Ritchie, David M

    2006-01-01

    A novel 96-well screen filter plate (patent pending) has been invented to eliminate a time-consuming and labor-intensive step in preparation of in vivo study samples--to remove blood or plasma clots. These clots plug the pipet tips during a manual or automated sample-transfer step causing inaccurate pipetting or total pipetting failure. Traditionally, these blood and plasma clots are removed by picking them out manually one by one from each sample tube before any sample transfer can be made. This has significantly slowed the sample preparation process and has become a bottleneck for automated high-throughput sample preparation using robotic liquid handlers. Our novel screen filter plate was developed to solve this problem. The 96-well screen filter plate consists of 96 stainless steel wire-mesh screen tubes connected to the 96 openings of a top plate so that the screen filter plate can be readily inserted into a 96-well sample storage plate. Upon insertion, the blood and plasma clots are excluded from entering the screen tube while clear sample solutions flow freely into it. In this way, sample transfer can be easily completed by either manual or automated pipetting methods. In this report, three structurally diverse compounds were selected to evaluate and validate the use of the screen filter plate. The plasma samples of these compounds were transferred and processed in the presence and absence of the screen filter plate and then analyzed by LC-MS/MS methods. Our results showed a good agreement between the samples prepared with and without the screen filter plate, demonstrating the utility and efficiency of this novel device for preparation of blood and plasma samples. The device is simple, easy to use, and reusable. It can be employed for sample preparation of other biological fluids that contain floating particulates or aggregates.

  6. Equipment for Topographical Preparation and Analysis of Various Semiconductor Infrared Detector Samples

    DTIC Science & Technology

    2015-11-13

    P Wijewarnasuriya at the Army Research Lab to understand the bandd offsets of HgCdTe infrared detector structures. Especially when a sample is not...Final Report: Equipment for Topographical Preparation and Analysis of Various Semiconductor Infrared Detector Samples Report Title A used calibrated...structures i. G15-38 and G15-38 Quantum Dot ---------------------------- 16 Infrared Detector Samples ii. GSU13-MPD-GB1 Heterostructure

  7. Sample preparation composite and replicate strategy case studies for assay of solid oral drug products.

    PubMed

    Nickerson, Beverly; Harrington, Brent; Li, Fasheng; Guo, Michele Xuemei

    2017-11-30

    Drug product assay is one of several tests required for new drug products to ensure the quality of the product at release and throughout the life cycle of the product. Drug product assay testing is typically performed by preparing a composite sample of multiple dosage units to obtain an assay value representative of the batch. In some cases replicate composite samples may be prepared and the reportable assay value is the average value of all the replicates. In previously published work by Harrington et al. (2014) [5], a sample preparation composite and replicate strategy for assay was developed to provide a systematic approach which accounts for variability due to the analytical method and dosage form with a standard error of the potency assay criteria based on compendia and regulatory requirements. In this work, this sample preparation composite and replicate strategy for assay is applied to several case studies to demonstrate the utility of this approach and its application at various stages of pharmaceutical drug product development. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Sample collection and preparation of biofluids and extracts for gas chromatography-mass spectrometry.

    PubMed

    Emwas, Abdul-Hamid M; Al-Talla, Zeyad A; Kharbatia, Najeh M

    2015-01-01

    To maximize the utility of gas chromatography-mass spectrometry (GC-MS) in metabonomics research, all stages of the experimental design should be standardized, including sample collection, storage, preparation, and sample separation. Moreover, the prerequisite for any GC-MS analysis is that a compound must be volatile and thermally stable if it is to be analyzed using this technique. Since many metabolites are nonvolatile and polar in nature, they are not readily amenable to analysis by GC-MS and require initial chemical derivatization of the polar functional groups in order to reduce the polarity and to increase the thermal stability and volatility of the analytes. In this chapter, an overview is presented of the optimum approach to sample collection, storage, and preparation for gas chromatography-mass spectrometry-based metabonomics with particular focus on urine samples as example of biofluids.

  9. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Procedures for preparing egg yolk... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic... chapter. (a) Under the supervision of an Authorized Agent or State Inspector, the eggs which are used in...

  10. Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography.

    PubMed

    Trépout, Sylvain; Bastin, Philippe; Marco, Sergio

    2017-03-12

    This report describes a protocol for preparing thick biological specimens for further observation using a scanning transmission electron microscope. It also describes an imaging method for studying the 3D structure of thick biological specimens by scanning transmission electron tomography. The sample preparation protocol is based on conventional methods in which the sample is fixed using chemical agents, treated with a heavy atom salt contrasting agent, dehydrated in a series of ethanol baths, and embedded in resin. The specific imaging conditions for observing thick samples by scanning transmission electron microscopy are then described. Sections of the sample are observed using a through-focus method involving the collection of several images at various focal planes. This enables the recovery of in-focus information at various heights throughout the sample. This particular collection pattern is performed at each tilt angle during tomography data collection. A single image is then generated, merging the in-focus information from all the different focal planes. A classic tilt-series dataset is then generated. The advantage of the method is that the tilt-series alignment and reconstruction can be performed using standard tools. The collection of through-focal images allows the reconstruction of a 3D volume that contains all of the structural details of the sample in focus.

  11. Development of High-Antifouling PPSU Ultrafiltration Membrane by Using Compound Additives: Preparation, Morphologies, and Filtration Resistant Properties

    PubMed Central

    Liu, Jie; Zhong, Zhencheng; Ma, Rui; Zhang, Weichen; Li, Jiding

    2016-01-01

    In this study, flat sheet asymmetric polyphenylsulfone (PPSU) ultrafiltration membranes with enhanced antifouling properties were prepared with a non-solvent induced phase separation (NIPS) method through compound additives containing a polymeric pore-forming agent, a small molecular non-solvent and a surfactant. The formation processes of the porous asymmetric membranes with different kinds of additives were studied in detail, and the microstructure controllable preparation of membrane was achieved by establishing a bridge between the membrane preparation parameters and separation performances. All prepared membranes were characterized by using a scanning electron microscope (SEM), contact angle analysis, porosity, maximum pore size, water and BSA solution permeability studies. The performance efficiency of the membrane was evaluated by using BSA as a model foulant in terms of permeability, solute rejection (R), Rm (membrane inherent resistance), Rc (cake layer resistance), and Rp (pore plugging resistance). The results showed that when the compound additives were used, the inter-connected pores were observed, maximum pore size, contact angle and membrane filtration resistance decreased, while the porosity increased. When PVP compound additives were added, the water flux increased from 80.4 to 148.1 L/(m2·h), the BSA rejection increased from 53.2% to 81.5%. A similar trend was observed for membranes with added PEG compound additives; the water flux and BSA rejection simultaneously increased. The filtration resistance decreased as a result of compound additives. The uniformity of membrane and the number of effective pores could be enhanced by adding compound additives through the cooperation of different additives. PMID:27338487

  12. Development of High-Antifouling PPSU Ultrafiltration Membrane by Using Compound Additives: Preparation, Morphologies, and Filtration Resistant Properties.

    PubMed

    Liu, Jie; Zhong, Zhencheng; Ma, Rui; Zhang, Weichen; Li, Jiding

    2016-06-21

    In this study, flat sheet asymmetric polyphenylsulfone (PPSU) ultrafiltration membranes with enhanced antifouling properties were prepared with a non-solvent induced phase separation (NIPS) method through compound additives containing a polymeric pore-forming agent, a small molecular non-solvent and a surfactant. The formation processes of the porous asymmetric membranes with different kinds of additives were studied in detail, and the microstructure controllable preparation of membrane was achieved by establishing a bridge between the membrane preparation parameters and separation performances. All prepared membranes were characterized by using a scanning electron microscope (SEM), contact angle analysis, porosity, maximum pore size, water and BSA solution permeability studies. The performance efficiency of the membrane was evaluated by using BSA as a model foulant in terms of permeability, solute rejection (R), Rm (membrane inherent resistance), Rc (cake layer resistance), and Rp (pore plugging resistance). The results showed that when the compound additives were used, the inter-connected pores were observed, maximum pore size, contact angle and membrane filtration resistance decreased, while the porosity increased. When PVP compound additives were added, the water flux increased from 80.4 to 148.1 L/(m²·h), the BSA rejection increased from 53.2% to 81.5%. A similar trend was observed for membranes with added PEG compound additives; the water flux and BSA rejection simultaneously increased. The filtration resistance decreased as a result of compound additives. The uniformity of membrane and the number of effective pores could be enhanced by adding compound additives through the cooperation of different additives.

  13. A novel PFIB sample preparation protocol for correlative 3D X-ray CNT and FIB-TOF-SIMS tomography.

    PubMed

    Priebe, Agnieszka; Audoit, Guillaume; Barnes, Jean-Paul

    2017-02-01

    We present a novel sample preparation method that allows correlative 3D X-ray Computed Nano-Tomography (CNT) and Focused Ion Beam Time-Of-Flight Secondary Ion Mass Spectrometry (FIB-TOF-SIMS) tomography to be performed on the same sample. In addition, our invention ensures that samples stay unmodified structurally and chemically between the subsequent experiments. The main principle is based on modifying the topography of the X-ray CNT experimental setup before FIB-TOF-SIMS measurements by incorporating a square washer around the sample. This affects the distribution of extraction field lines and therefore influences the trajectories of secondary ions that are now guided more efficiently towards the detector. As the result, secondary ion detection is significantly improved and higher, i.e. statistically better, signals are obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Addition of senna improves quality of colonoscopy preparation with magnesium citrate.

    PubMed

    Vradelis, Stergios; Kalaitzakis, Evangelos; Sharifi, Yalda; Buchel, Otto; Keshav, Satish; Chapman, Roger W; Braden, Barbara

    2009-04-14

    To prospectively investigate the effectiveness and patient's tolerance of two low-cost bowel cleansing preparation protocols based on magnesium citrate only or the combination of magnesium citrate and senna. A total of 342 patients who were referred for colonoscopy underwent a colon cleansing protocol with magnesium citrate alone (n = 160) or magnesium citrate and senna granules (n = 182). The colonoscopist rated the overall efficacy of colon cleansing using an established score on a 4-point scale. Patients were questioned before undergoing colonoscopy for side effects and symptoms during bowel preparation. The percentage of procedures rescheduled because of insufficient colon cleansing was 7% in the magnesium citrate group and 4% in the magnesium citrate/senna group (P = 0.44). Adequate visualization of the colonic mucosa was rated superior under the citramag/senna regimen (P = 0.004). Both regimens were well tolerated, and did not significantly differ in the occurrence of nausea, bloating or headache. However, abdominal cramps were observed more often under the senna protocol (29.2%) compared to the magnesium citrate only protocol (9.9%, P < 0.0003). The addition of senna to the bowel preparation protocol with magnesium citrate significantly improves the cleansing outcome.

  15. La 2-xSr xCuO 4-δ superconducting samples prepared by the wet-chemical method

    NASA Astrophysics Data System (ADS)

    Loose, A.; Gonzalez, J. L.; Lopez, A.; Borges, H. A.; Baggio-Saitovitch, E.

    2009-10-01

    In this work, we report on the physical properties of good-quality polycrystalline superconducting samples of La 2-xSr xCu 1-yZn yO 4-δ ( y=0, 0.02) prepared by a wet-chemical method, focusing on the temperature dependence of the critical current. Using the wet-chemical method, we were able to produce samples with improved homogeneity compared to the solid-state method. A complete set of samples with several carrier concentrations, ranging from the underdoped (strontium concentration x≈0.05) to the highly overdoped ( x≈0.25) region, were prepared and investigated. The X-ray diffraction analysis, zero-field cooling magnetization and electrical resistivity measurements were reported on earlier. The structural parameters of the prepared samples seem to be slightly modified by the preparation method and their critical temperatures were lower than reported in the literature. The temperature dependence of the critical current was explained by a theoretical model which took the granular structure of the samples into account.

  16. Preparation and validation of gross alpha/beta samples used in EML`s quality assessment program

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Scarpitta, S.C.

    1997-10-01

    A set of water and filter samples have been incorporated into the existing Environmental Measurements Laboratory`s (EML) Quality Assessment Program (QAP) for gross alpha/beta determinations by participating DOE laboratories. The participating laboratories are evaluated by comparing their results with the EML value. The preferred EML method for measuring water and filter samples, described in this report, uses gas flow proportional counters with 2 in. detectors. Procedures for sample preparation, quality control and instrument calibration are presented. Liquid scintillation (LS) counting is an alternative technique that is suitable for quantifying both the alpha ({sup 241}Am, {sup 230}Th and {sup 238}Pu) andmore » beta ({sup 90}Sr/{sup 90}Y) activity concentrations in the solutions used to prepare the QAP water and air filter samples. Three LS counting techniques (Cerenkov, dual dpm and full spectrum analysis) are compared. These techniques may be used to validate the activity concentrations of each component in the alpha/beta solution before the QAP samples are actually prepared.« less

  17. High-Temperature Oxidation of Fe3Al Intermetallic Alloy Prepared by Additive Manufacturing LENS

    PubMed Central

    Łyszkowski, Radosław

    2015-01-01

    The isothermal oxidation of Fe-28Al-5Cr (at%) intermetallic alloy microalloyed with Zr and B (<0.08 at%) in air atmosphere, in the temperature range of 1000 to 1200 °C, was studied. The investigation was carried out on the thin-walled (<1 mm) elements prepared by Laser Engineered Net Shaping (LENS) from alloy powder of a given composition. Characterization of the specimens, after the oxidation, was conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM, with back-scatter detector (BSE) and energy-dispersive X-ray spectroscopy (EDS) attachments). The investigation has shown, that the oxidized samples were covered with a thin, homogeneous α-Al2O3 oxide layers. The intensity of their growth indicates that the material lost its resistance to oxidation at 1200 °C. Structural analysis of the thin-walled components’ has not shown intensification of the oxidation process at the joints of additive layers. PMID:28788014

  18. Metabolomic analysis-Addressing NMR and LC-MS related problems in human feces sample preparation.

    PubMed

    Moosmang, Simon; Pitscheider, Maria; Sturm, Sonja; Seger, Christoph; Tilg, Herbert; Halabalaki, Maria; Stuppner, Hermann

    2017-10-31

    Metabolomics is a well-established field in fundamental clinical research with applications in different human body fluids. However, metabolomic investigations in feces are currently an emerging field. Fecal sample preparation is a demanding task due to high complexity and heterogeneity of the matrix. To gain access to the information enclosed in human feces it is necessary to extract the metabolites and make them accessible to analytical platforms like NMR or LC-MS. In this study different pre-analytical parameters and factors were investigated i.e. water content, different extraction solvents, influence of freeze-drying and homogenization, ratios of sample weight to extraction solvent, and their respective impact on metabolite profiles acquired by NMR and LC-MS. The results indicate that profiles are strongly biased by selection of extraction solvent or drying of samples, which causes different metabolites to be lost, under- or overstated. Additionally signal intensity and reproducibility of the measurement were found to be strongly dependent on sample pre-treatment steps: freeze-drying and homogenization lead to improved release of metabolites and thus increased signals, but at the same time induced variations and thus deteriorated reproducibility. We established the first protocol for extraction of human fecal samples and subsequent measurement with both complementary techniques NMR and LC-MS. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Transmission Electron Microscopy (TEM) Sample Preparation of Si(1-x)Gex in c-Plane Sapphire Substrate

    NASA Technical Reports Server (NTRS)

    Kim, Hyun Jung; Choi, Sang H.; Bae, Hyung-Bin; Lee, Tae Woo

    2012-01-01

    The National Aeronautics and Space Administration-invented X-ray diffraction (XRD) methods, including the total defect density measurement method and the spatial wafer mapping method, have confirmed super hetero epitaxy growth for rhombohedral single crystalline silicon germanium (Si1-xGex) on a c-plane sapphire substrate. However, the XRD method cannot observe the surface morphology or roughness because of the method s limited resolution. Therefore the authors used transmission electron microscopy (TEM) with samples prepared in two ways, the focused ion beam (FIB) method and the tripod method to study the structure between Si1-xGex and sapphire substrate and Si1?xGex itself. The sample preparation for TEM should be as fast as possible so that the sample should contain few or no artifacts induced by the preparation. The standard sample preparation method of mechanical polishing often requires a relatively long ion milling time (several hours), which increases the probability of inducing defects into the sample. The TEM sampling of the Si1-xGex on sapphire is also difficult because of the sapphire s high hardness and mechanical instability. The FIB method and the tripod method eliminate both problems when performing a cross-section TEM sampling of Si1-xGex on c-plane sapphire, which shows the surface morphology, the interface between film and substrate, and the crystal structure of the film. This paper explains the FIB sampling method and the tripod sampling method, and why sampling Si1-xGex, on a sapphire substrate with TEM, is necessary.

  20. Preparation of pure microbiological samples for pyrolysis of gas-liquid chromatography studies.

    PubMed Central

    Oxborrow, G S; Fields, N D; Puleo, J R

    1976-01-01

    Bacterial samples were prepared for pyrolysis gas-liquid chromatography using cells grown on membrane filters. Pyrochromatograms were reproducible when cells harvested from the filters were pyrolyzed without being washed. Images PMID:970947

  1. Sample preparation method influences direct identification of anaerobic bacteria from positive blood culture bottles using MALDI-TOF MS.

    PubMed

    Jeverica, Samo; Nagy, Elisabeth; Mueller-Premru, Manica; Papst, Lea

    2018-05-15

    Rapid detection and identification of anaerobic bacteria from blood is important to adjust antimicrobial therapy by including antibiotics with activity against anaerobic bacteria. Limited data is available about direct identification of anaerobes from positive blood culture bottles using MALDI-TOF mass spectrometry (MS). In this study, we evaluated the performance of two sample preparation protocols for direct identification of anaerobes from positive blood culture bottles, the MALDI Sepsityper kit (Sepsityper) and the in-house saponin (saponin) method. Additionally, we compared two blood culture bottle types designed to support the growth of anaerobic bacteria, the BacT/ALERT-FN Plus (FN Plus) and the BACTEC-Lytic (Lytic), and their influence on direct identification. A selection of 30 anaerobe strains belonging to 22 different anaerobic species (11 reference strains and 19 clinical isolates) were inoculated to 2 blood culture bottle types in duplicate. In total, 120 bottles were inoculated and 99.2% (n = 119) signalled growth within 5 days of incubation. The Sepsityper method correctly identified 56.3% (n = 67) of anaerobes, while the saponin method correctly identified 84.9% (n = 101) of anaerobes with at least log(score) ≥1.6 (low confidence correct identification), (p < 0.001). Gram negative anaerobes were better identified with the saponin method (100% vs. 46.5%; p < 0.001), while Gram positive anaerobes were better identified with the Sepsityper method (70.8% vs. 62.5%; p = 0.454). Average log(score) values among only those isolates that were correctly identified simultaneously by both sample preparation methods were 2.119 and 2.029 in favour of the Sepsityper method, (p = 0.019). The inoculated bottle type didn't influence the performance of the two sample preparation methods. We confirmed that direct identification from positive blood culture bottles with MALDI-TOF MS is reliable for anaerobic bacteria. However, the results

  2. A comparison of sample preparation strategies for biological tissues and subsequent trace element analysis using LA-ICP-MS.

    PubMed

    Bonta, Maximilian; Török, Szilvia; Hegedus, Balazs; Döme, Balazs; Limbeck, Andreas

    2017-03-01

    Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is one of the most commonly applied methods for lateral trace element distribution analysis in medical studies. Many improvements of the technique regarding quantification and achievable lateral resolution have been achieved in the last years. Nevertheless, sample preparation is also of major importance and the optimal sample preparation strategy still has not been defined. While conventional histology knows a number of sample pre-treatment strategies, little is known about the effect of these approaches on the lateral distributions of elements and/or their quantities in tissues. The technique of formalin fixation and paraffin embedding (FFPE) has emerged as the gold standard in tissue preparation. However, the potential use for elemental distribution studies is questionable due to a large number of sample preparation steps. In this work, LA-ICP-MS was used to examine the applicability of the FFPE sample preparation approach for elemental distribution studies. Qualitative elemental distributions as well as quantitative concentrations in cryo-cut tissues as well as FFPE samples were compared. Results showed that some metals (especially Na and K) are severely affected by the FFPE process, whereas others (e.g., Mn, Ni) are less influenced. Based on these results, a general recommendation can be given: FFPE samples are completely unsuitable for the analysis of alkaline metals. When analyzing transition metals, FFPE samples can give comparable results to snap-frozen tissues. Graphical abstract Sample preparation strategies for biological tissues are compared with regard to the elemental distributions and average trace element concentrations.

  3. The effect of addition of selected milk protein preparations on the growth of Lactobacillus acidophilus and physicochemical properties of fermented milk.

    PubMed

    Gustaw, Waldemar; Kozioł, Justyna; Radzki, Wojciech; Skrzypczak, Katarzyna; Michalak-Majewska, Monika; Sołowiej, Bartosz; Sławińska, Aneta; Jabłońska-Ryś, Ewa

    2016-01-01

    The intake of fermented milk products, especially yoghurts, has been systematically increasing for a few decades. The purpose of this work was to obtain milk products fermented with a mix of bacterial cultures (yoghurt bacteria and Lactobacillus acidophillus LA-5) and enriched with selected milk protein preparations. Secondly, the aim of the work was to determine physiochemical and rheological properties of the obtained products. The following additives were applied in the experiment: whey protein concentrate (WPC 65), whey protein isolate (WPI), demineralised whey powder (SPD), caseinoglycomacropeptide (CGMP), α-lactalbumin (α-la), sodium caseinate (KNa) and calcium caseinate (KCa). Milk was fermented using probiotic strain Lactobacillus acidophillus LA-5 and a typical yoghurt culture. The products were analysed in terms of the survivability of bacterial cells during refrigerated storage, rheological properties and syneresis. Fermented milk products were obtained using blends of bacterial strains: ST-B01:Lb-12 (1:1), ST-B01:Lb-12:LA-5 (1:1:2). Milk beverages fermented with typical yoghurt bacteria and LA-5 strain showed intensive syneresis. The addition of LA-5 strain caused formation of harder acid gels, comparing to typical yoghurts. Milk products which were prepared from skimmed milk possessed higher values of hardness and consistency coefficient. The increase of concentrations of milk preparations (except of WPI) did not cause significant differences in the hardness of acidic gels obtained by fermentation of mixed culture with a probiotic strain. The applied preparations improved physiochemical properties of the milk beverages which were prepared with a probiotic strain. The increase of protein milk preparations concentration resulted in a gradual decrease of the secreted whey. Among the products that were made of full milk powder and were subjected to three weeks of refrigerated storage the highest survivability of Lb. acidophilus LA-5 was noticed in the

  4. Polished sample preparing and backscattered electron imaging and of fly ash-cement paste

    NASA Astrophysics Data System (ADS)

    Feng, Shuxia; Li, Yanqi

    2018-03-01

    In recent decades, the technology of backscattered electron imaging and image analysis was applied in more and more study of mixed cement paste because of its special advantages. Test accuracy of this technology is affected by polished sample preparation and image acquisition. In our work, effects of two factors in polished sample preparing and backscattered electron imaging were investigated. The results showed that increasing smoothing pressure could improve the flatness of polished surface and then help to eliminate interference of morphology on grey level distribution of backscattered electron images; increasing accelerating voltage was beneficial to increase gray difference among different phases in backscattered electron images.

  5. The ExoMars Sample Preparation and Distribution System

    NASA Astrophysics Data System (ADS)

    Schulte, Wolfgang; Hofmann, Peter; Baglioni, Pietro; Richter, Lutz; Redlich, . Daniel; Notarnicola, Marco; Durrant, Stephen

    2012-07-01

    The Sample Preparation and Distribution System (SPDS) is a key element of the ESA ExoMars Rover. It is a set of complex mechanisms designed to receive Mars soil samples acquired from the subsurface with a drill, to crush them and to distribute the obtained soil powder to the scientific instruments of the `Pasteur Payload', in the Rover Analytical Laboratory (ALD). In particular, the SPDS consists of: (1) a Core Sample Handling System (CSHS), including a Core Sample Transportation Mechanism (CSTM) and a Blank Sample Dispenser; (2) a Crushing Station (CS); (3) a Powder Sample Dosing and Distribution System (PSDDS); and (4) a Powder Sample Handling System (PSHS) which is a carousel carrying pyrolysis ovens, a re-fillable sample container and a tool to flatten the powder sample surface. Kayser-Threde has developed, undercontract with the ExoMars prime contractor Thales Alenia Space Italy, breadboards and an engineering model of the SPDS mechanisms. Tests of individual mechanisms, namely the CSTM, CS and PSDDS were conducted both in laboratory ambient conditions and in a simulated Mars environment, using dedicated facilities. The SPDS functionalities and performances were measured and evaluated. In the course of 2011 the SPDS Dosing Station (part of the PSDDS) was also tested in simulated Mars gravity conditions during a parabolic flight campaign. By the time of the conference, an elegant breadboard of the Powder Sample Handling System will have been built and tested. The next step, planned by mid of 2012, will be a complete end-to-end test of the sample handling and processing chain, combining all four SPDS mechanisms. The possibility to verify interface and operational aspects between the SPDS and the ALD scientific instruments using the available instruments breadboards with the end-to-end set-up is currently being evaluated. This paper illustrates the most recent design status of the SPDS mechanisms, summarizes the test results and highlights future development

  6. Sample preparation for total reflection X-ray fluorescence analysis using resist pattern technique

    NASA Astrophysics Data System (ADS)

    Tsuji, K.; Yomogita, N.; Konyuba, Y.

    2018-06-01

    A circular resist pattern layer with a diameter of 9 mm was prepared on a glass substrate (26 mm × 76 mm; 1.5 mm thick) for total reflection X-ray fluorescence (TXRF) analysis. The parallel cross pattern was designed with a wall thickness of 10 μm, an interval of 20 μm, and a height of 1.4 or 0.8 μm. This additional resist layer did not significantly increase background intensity on the XRF peaks in TXRF spectra. Dotted residue was obtained from a standard solution (10 μL) containing Ti, Cr, Ni, Pb, and Ga, each at a final concentration of 10 ppm, on a normal glass substrate with a silicone coating layer. The height of the residue was more than 100 μm, where self-absorption in the large residue affected TXRF quantification (intensity relative standard deviation (RSD): 12-20%). In contrast, from a droplet composed of a small volume of solution dropped and cast on the resist pattern structure, the obtained residue was not completely film but a film-like residue with a thickness less than 1 μm, where self-absorption was not a serious problem. In the end, this sample preparation was demonstrated to improve TXRF quantification (intensity RSD: 2-4%).

  7. Fuel additives and heat treatment effects on nanocrystalline zinc ferrite phase composition

    NASA Astrophysics Data System (ADS)

    Hu, Ping; Pan, De-an; Wang, Xin-feng; Tian, Jian-jun; Wang, Jian; Zhang, Shen-gen; Volinsky, Alex A.

    2011-03-01

    Nanocrystalline ZnFe 2O 4 powder was prepared by the auto-combustion method using citric acid, acetic acid, carbamide and acrylic acid as fuel additives. Pure spinel zinc ferrite with the crystallite size of about 15 nm can be obtained by using acrylic acid as fuel additive. Samples prepared using other fuel additives contain ZnO impurities. In order to eliminate ZnO impurities, the sample prepared with citric acid as fuel additive was annealed at different temperatures up to 1000 °C in air and in argon. Annealed powders have pure ZnFe 2O 4 phase when annealing temperature is higher than 650 °C in air. Sample annealed at 650 °C in air is paramagnetic. However, annealed powders become a mixture of Fe 3O 4 and FeO after annealing at 1000 °C in argon atmosphere due to Zn volatility and the reduction reaction.

  8. A Simple and Reproducible Method to Prepare Membrane Samples from Freshly Isolated Rat Brain Microvessels.

    PubMed

    Brzica, Hrvoje; Abdullahi, Wazir; Reilly, Bianca G; Ronaldson, Patrick T

    2018-05-07

    The blood-brain barrier (BBB) is a dynamic barrier tissue that responds to various pathophysiological and pharmacological stimuli. Such changes resulting from these stimuli can greatly modulate drug delivery to the brain and, by extension, cause considerable challenges in the treatment of central nervous system (CNS) diseases. Many BBB changes that affect pharmacotherapy, involve proteins that are localized and expressed at the level of endothelial cells. Indeed, such knowledge on BBB physiology in health and disease has sparked considerable interest in the study of these membrane proteins. From a basic science research standpoint, this implies a requirement for a simple but robust and reproducible method for isolation of microvessels from brain tissue harvested from experimental animals. In order to prepare membrane samples from freshly isolated microvessels, it is essential that sample preparations be enriched in endothelial cells but limited in the presence of other cell types of the neurovascular unit (i.e., astrocytes, microglia, neurons, pericytes). An added benefit is the ability to prepare samples from individual animals in order to capture the true variability of protein expression in an experimental population. In this manuscript, details regarding a method that is utilized for isolation of rat brain microvessels and preparation of membrane samples are provided. Microvessel enrichment, from samples derived, is achieved by using four centrifugation steps where dextran is included in the sample buffer. This protocol can easily be adapted by other laboratories for their own specific applications. Samples generated from this protocol have been shown to yield robust experimental data from protein analysis experiments that can greatly aid the understanding of BBB responses to physiological, pathophysiological, and pharmacological stimuli.

  9. Saccharose solid matrix embedded proteins: a new method for sample preparation for X-ray absorption spectroscopy.

    PubMed

    Ascone, I; Sabatucci, A; Bubacco, L; Di Muro, P; Salvato, B

    2000-01-01

    In this study, solid samples of hemoglobin and hemocyanin have been prepared by embedding the proteins into a saccharose-based matrix. These materials have been developed specifically for specimens for X-ray absorption spectroscopy (XAS). The preservation of protein conformation and active site organization was tested, making comparisons between the solid and the corresponding liquid samples, using resonance Raman, infra red, fluorescence and XAS. The XAS spectra of irradiated solid and liquid samples were then compared, and the preservation of biological activity of the proteins during both preparation procedure and X-ray irradiation was assessed. In all cases, the measurements clearly demonstrate that protein solid samples are both structurally and functionally quite well preserved, much better than those in the liquid state. The saccharose matrix provides an excellent protection against X-ray damages, allowing for longer exposure to the X-ray beam. Moreover, the demonstrated long-term stability of samples permits their preparation and storage in optimal conditions, allowing for the repetition of data collection with the same sample in several experimental sessions. The very high protein concentration that can be reached results in a significantly better signal-to-noise ratio, particularly useful for high molecular weight proteins with a low metal-to-protein ratio. On the bases of the above-mentioned results, we propose the new method as a standard procedure for the preparation of biological samples to be used for XAS spectroscopy.

  10. Addition of senna improves quality of colonoscopy preparation with magnesium citrate

    PubMed Central

    Vradelis, Stergios; Kalaitzakis, Evangelos; Sharifi, Yalda; Buchel, Otto; Keshav, Satish; Chapman, Roger W; Braden, Barbara

    2009-01-01

    AIM: To prospectively investigate the effectiveness and patient’s tolerance of two low-cost bowel cleansing preparation protocols based on magnesium citrate only or the combination of magnesium citrate and senna. METHODS: A total of 342 patients who were referred for colonoscopy underwent a colon cleansing protocol with magnesium citrate alone (n = 160) or magnesium citrate and senna granules (n = 182). The colonoscopist rated the overall efficacy of colon cleansing using an established score on a 4-point scale. Patients were questioned before undergoing colonoscopy for side effects and symptoms during bowel preparation. RESULTS: The percentage of procedures rescheduled because of insufficient colon cleansing was 7% in the magnesium citrate group and 4% in the magnesium citrate/senna group (P = 0.44). Adequate visualization of the colonic mucosa was rated superior under the citramag/senna regimen (P = 0.004). Both regimens were well tolerated, and did not significantly differ in the occurrence of nausea, bloating or headache. However, abdominal cramps were observed more often under the senna protocol (29.2%) compared to the magnesium citrate only protocol (9.9%, P < 0.0003). CONCLUSION: The addition of senna to the bowel preparation protocol with magnesium citrate significantly improves the cleansing outcome. PMID:19360920

  11. Sample preparation for SFM imaging of DNA, proteins, and DNA-protein complexes.

    PubMed

    Ristic, Dejan; Sanchez, Humberto; Wyman, Claire

    2011-01-01

    Direct imaging is invaluable for understanding the mechanism of complex genome transactions where proteins work together to organize, transcribe, replicate, and repair DNA. Scanning (or atomic) force microscopy is an ideal tool for this, providing 3D information on molecular structure at nanometer resolution from defined components. This is a convenient and practical addition to in vitro studies as readily obtainable amounts of purified proteins and DNA are required. The images reveal structural details on the size and location of DNA-bound proteins as well as protein-induced arrangement of the DNA, which are directly correlated in the same complexes. In addition, even from static images, the different forms observed and their relative distributions can be used to deduce the variety and stability of different complexes that are necessarily involved in dynamic processes. Recently available instruments that combine fluorescence with topographic imaging allow the identification of specific molecular components in complex assemblies, which broadens the applications and increases the information obtained from direct imaging of molecular complexes. We describe here basic methods for preparing samples of proteins, DNA, and complexes of the two for topographic imaging and quantitative analysis. We also describe special considerations for combined fluorescence and topographic imaging of molecular complexes.

  12. An overview of the main foodstuff sample preparation technologies for tetracycline residue determination.

    PubMed

    Pérez-Rodríguez, Michael; Pellerano, Roberto Gerardo; Pezza, Leonardo; Pezza, Helena Redigolo

    2018-05-15

    Tetracyclines are widely used for both the treatment and prevention of diseases in animals as well as for the promotion of rapid animal growth and weight gain. This practice may result in trace amounts of these drugs in products of animal origin, such as milk and eggs, posing serious risks to human health. The presence of tetracycline residues in foods can lead to the transmission of antibiotic-resistant pathogenic bacteria through the food chain. In order to ensure food safety and avoid exposure to these substances, national and international regulatory agencies have established tolerance levels for authorized veterinary drugs, including tetracycline antimicrobials. In view of that, numerous sensitive and specific methods have been developed for the quantification of these compounds in different food matrices. One will note, however, that the determination of trace residues in foods such as milk and eggs often requires extensive sample extraction and preparation prior to conducting instrumental analysis. Sample pretreatment is usually the most complicated step in the analytical process and covers both cleaning and pre-concentration. Optimal sample preparation can reduce analysis time and sources of error, enhance sensitivity, apart from enabling unequivocal identification, confirmation and quantification of target analytes. The development and implementation of more environmentally friendly analytical procedures, which involve the use of less hazardous solvents and smaller sample sizes compared to traditional methods, is a rapidly increasing trend in analytical chemistry. This review seeks to provide an updated overview of the main trends in sample preparation for the determination of tetracycline residues in foodstuffs. The applicability of several extraction and clean-up techniques employed in the analysis of foodstuffs, especially milk and egg samples, is also thoroughly discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Challenges of biological sample preparation for SIMS imaging of elements and molecules at subcellular resolution

    NASA Astrophysics Data System (ADS)

    Chandra, Subhash

    2008-12-01

    Secondary ion mass spectrometry (SIMS) based imaging techniques capable of subcellular resolution characterization of elements and molecules are becoming valuable tools in many areas of biology and medicine. Due to high vacuum requirements of SIMS, the live cells cannot be analyzed directly in the instrument. The sample preparation, therefore, plays a critical role in preserving the native chemical composition for SIMS analysis. This work focuses on the evaluation of frozen-hydrated and frozen freeze-dried sample preparations for SIMS studies of cultured cells with a CAMECA IMS-3f dynamic SIMS ion microscope instrument capable of producing SIMS images with a spatial resolution of 500 nm. The sandwich freeze-fracture method was used for fracturing the cells. The complimentary fracture planes in the plasma membrane were characterized by field-emission secondary electron microscopy (FESEM) in the frozen-hydrated state. The cells fractured at the dorsal surface were used for SIMS analysis. The frozen-hydrated SIMS analysis of individual cells under dynamic primary ion beam (O 2+) revealed local secondary ion signal enhancements correlated with the water image signals of 19(H 3O) +. A preferential removal of water from the frozen cell matrix in the Z-axis was also observed. These complications render the frozen-hydrated sample type less desirable for subcellular dynamic SIMS studies. The freeze-drying of frozen-hydrated cells, either inside the instrument or externally in a freeze-drier, allowed SIMS imaging of subcellular chemical composition. Morphological evaluations of fractured freeze-dried cells with SEM and confocal laser scanning microscopy (CLSM) revealed well-preserved mitochondria, Golgi apparatus, and stress fibers. SIMS analysis of fractured freeze-dried cells revealed well-preserved chemical composition of even the most highly diffusible ions like K + and Na + in physiologically relevant concentrations. The high K-low Na signature in individual cells

  14. 14C sample preparation for AMS microdosing studies at Lund University using online combustion and septa-sealed vials

    NASA Astrophysics Data System (ADS)

    Sydoff, Marie; Stenström, Kristina

    2010-04-01

    The Department of Physics at Lund University is participating in a European Union project called EUMAPP (European Union Microdose AMS Partnership Programme), in which sample preparation and accelerator mass spectrometry (AMS) measurements of biological samples from microdosing studies have been made. This paper describes a simplified method of converting biological samples to solid graphite for 14C analysis with AMS. The method is based on online combustion of the samples, and reduction of CO 2 in septa-sealed vials. The septa-sealed vials and disposable materials are used to eliminate sample cross-contamination. Measurements of ANU and Ox I standards show deviations of 2% and 3%, respectively, relative to reference values. This level of accuracy is sufficient for biological samples from microdosing studies. Since the method has very few handling steps from sample to graphite, the risk of failure during the sample preparation process is minimized, making the method easy to use in routine preparation of samples.

  15. Rapid Microbial Sample Preparation from Blood Using a Novel Concentration Device

    PubMed Central

    Boardman, Anna K.; Campbell, Jennifer; Wirz, Holger; Sharon, Andre; Sauer-Budge, Alexis F.

    2015-01-01

    Appropriate care for bacteremic patients is dictated by the amount of time needed for an accurate diagnosis. However, the concentration of microbes in the blood is extremely low in these patients (1–100 CFU/mL), traditionally requiring growth (blood culture) or amplification (e.g., PCR) for detection. Current culture-based methods can take a minimum of two days, while faster methods like PCR require a sample free of inhibitors (i.e., blood components). Though commercial kits exist for the removal of blood from these samples, they typically capture only DNA, thereby necessitating the use of blood culture for antimicrobial testing. Here, we report a novel, scaled-up sample preparation protocol carried out in a new microbial concentration device. The process can efficiently lyse 10 mL of bacteremic blood while maintaining the microorganisms’ viability, giving a 30‑μL final output volume. A suite of six microorganisms (Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, Pseudomonas aeruginosa, and Candida albicans) at a range of clinically relevant concentrations was tested. All of the microorganisms had recoveries greater than 55% at the highest tested concentration of 100 CFU/mL, with three of them having over 70% recovery. At the lowest tested concentration of 3 CFU/mL, two microorganisms had recoveries of ca. 40–50% while the other four gave recoveries greater than 70%. Using a Taqman assay for methicillin-sensitive S. aureus (MSSA)to prove the feasibility of downstream analysis, we show that our microbial pellets are clean enough for PCR amplification. PCR testing of 56 spiked-positive and negative samples gave a specificity of 0.97 and a sensitivity of 0.96, showing that our sample preparation protocol holds great promise for the rapid diagnosis of bacteremia directly from a primary sample. PMID:25675242

  16. The role of sample preparation in interpretation of trace element concentration variability in moss bioindication studies

    USGS Publications Warehouse

    Migaszewski, Z.M.; Lamothe, P.J.; Crock, J.G.; Galuszka, A.; Dolegowska, S.

    2011-01-01

    Trace element concentrations in plant bioindicators are often determined to assess the quality of the environment. Instrumental methods used for trace element determination require digestion of samples. There are different methods of sample preparation for trace element analysis, and the selection of the best method should be fitted for the purpose of a study. Our hypothesis is that the method of sample preparation is important for interpretation of the results. Here we compare the results of 36 element determinations performed by ICP-MS on ashed and on acid-digested (HNO3, H2O2) samples of two moss species (Hylocomium splendens and Pleurozium schreberi) collected in Alaska and in south-central Poland. We found that dry ashing of the moss samples prior to analysis resulted in considerably lower detection limits of all the elements examined. We also show that this sample preparation technique facilitated the determination of interregional and interspecies differences in the chemistry of trace elements. Compared to the Polish mosses, the Alaskan mosses displayed more positive correlations of the major rock-forming elements with ash content, reflecting those elements' geogenic origin. Of the two moss species, P. schreberi from both Alaska and Poland was also highlighted by a larger number of positive element pair correlations. The cluster analysis suggests that the more uniform element distribution pattern of the Polish mosses primarily reflects regional air pollution sources. Our study has shown that the method of sample preparation is an important factor in statistical interpretation of the results of trace element determinations. ?? 2010 Springer-Verlag.

  17. Development of a Novel Self-Enclosed Sample Preparation Device for DNA/RNA Isolation in Space

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Mehta, Satish K.; Pensinger, Stuart J.; Pickering, Karen D.

    2011-01-01

    Modern biology techniques present potentials for a wide range of molecular, cellular, and biochemistry applications in space, including detection of infectious pathogens and environmental contaminations, monitoring of drug-resistant microbial and dangerous mutations, identification of new phenotypes of microbial and new life species. However, one of the major technological blockades in enabling these technologies in space is a lack of devices for sample preparation in the space environment. To overcome such an obstacle, we constructed a prototype of a DNA/RNA isolation device based on our novel designs documented in the NASA New Technology Reporting System (MSC-24811-1/3-1). This device is self-enclosed and pipette free, purposely designed for use in the absence of gravity. Our design can also be modified easily for preparing samples in space for other applications, such as flowcytometry, immunostaining, cell separation, sample purification and separation according to its size and charges, sample chemical labeling, and sample purification. The prototype of our DNA/RNA isolation device was tested for efficiencies of DNA and RNA isolation from various cell types for PCR analysis. The purity and integrity of purified DNA and RNA were determined as well. Results showed that our developed DNA/RNA isolation device offers similar efficiency and quality in comparison to the samples prepared using the standard protocol in the laboratory.

  18. Soil and Water – What is Detectable through Microbiological Sample Preparation Techniques

    EPA Science Inventory

    The concerns of a potential terrorist’s use of biological agents in soil and ground water are articulated by comparisons to major illnesses in this Country involving contaminated drinking water sources. Objectives are focused on the importance of sample preparation in the rapid, ...

  19. Sample preparation and storage can change arsenic speciation in human urine.

    PubMed

    Feldmann, J; Lai, V W; Cullen, W R; Ma, M; Lu, X; Le, X C

    1999-11-01

    Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and -20 degrees C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethylammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and -20 degrees C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and -20 degrees C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. Low temperature (4 and -20 degrees C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis.

  20. Methods of biological fluids sample preparation - biogenic amines, methylxanthines, water-soluble vitamins.

    PubMed

    Płonka, Joanna

    2015-01-01

    In recent years demands on the amount of information that can be obtained from the analysis of a single sample have increased. For time and economic reasons it is necessary to examine at the same time larger number of compounds, and compounds from different groups. This can best be seen in such areas as clinical analysis. In many diseases, the best results for patients are obtained when treatment fits the individual characteristics of the patient. Dosage monitoring is important at the beginning of therapy and in the full process of treatment. In the treatment of many diseases biogenic amines (dopamine, serotonin) and methylxanthines (theophylline, theobromine, caffeine) play an important role. They are used as drugs separately or in combination with others to support and strengthen the action of other drugs - for example, the combination of caffeine and paracetamol. Vitamin supplementation may be also an integral part of the treatment process. Specification of complete sample preparation parameters for extraction of the above compounds from biological matrices has been reviewed. Particular attention was given to the preparation stage and extraction methods. This review provides universal guidance on establishing a common procedures across laboratories to facilitate the preparation and analysis of all discussed compounds. Copyright © 2014 John Wiley & Sons, Ltd.

  1. Autonomous microfluidic sample preparation system for protein profile-based detection of aerosolized bacterial cells and spores.

    PubMed

    Stachowiak, Jeanne C; Shugard, Erin E; Mosier, Bruce P; Renzi, Ronald F; Caton, Pamela F; Ferko, Scott M; Van de Vreugde, James L; Yee, Daniel D; Haroldsen, Brent L; VanderNoot, Victoria A

    2007-08-01

    For domestic and military security, an autonomous system capable of continuously monitoring for airborne biothreat agents is necessary. At present, no system meets the requirements for size, speed, sensitivity, and selectivity to warn against and lead to the prevention of infection in field settings. We present a fully automated system for the detection of aerosolized bacterial biothreat agents such as Bacillus subtilis (surrogate for Bacillus anthracis) based on protein profiling by chip gel electrophoresis coupled with a microfluidic sample preparation system. Protein profiling has previously been demonstrated to differentiate between bacterial organisms. With the goal of reducing response time, multiple microfluidic component modules, including aerosol collection via a commercially available collector, concentration, thermochemical lysis, size exclusion chromatography, fluorescent labeling, and chip gel electrophoresis were integrated together to create an autonomous collection/sample preparation/analysis system. The cycle time for sample preparation was approximately 5 min, while total cycle time, including chip gel electrophoresis, was approximately 10 min. Sensitivity of the coupled system for the detection of B. subtilis spores was 16 agent-containing particles per liter of air, based on samples that were prepared to simulate those collected by wetted cyclone aerosol collector of approximately 80% efficiency operating for 7 min.

  2. Preparing to Receive and Handle Martian Samples When They Arrive on Earth

    NASA Technical Reports Server (NTRS)

    McCubbin, Francis M.

    2017-01-01

    The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10F+ derivative NPR 'Curation of Extraterrestrial Materials', JSC is charged with 'The curation of all extraterrestrial material under NASA control, including future NASA missions. 'The Directive goes on to define Curation as including'...documentation, preservation, preparation, and distribution of samples for research, education, and public outreach."

  3. Recent trends in sorption-based sample preparation and liquid chromatography techniques for food analysis.

    PubMed

    V Soares Maciel, Edvaldo; de Toffoli, Ana Lúcia; Lanças, Fernando Mauro

    2018-04-20

    The accelerated rising of the world's population increased the consumption of food, thus demanding more rigors in the control of residue and contaminants in food-based products marketed for human consumption. In view of the complexity of most food matrices, including fruits, vegetables, different types of meat, beverages, among others, a sample preparation step is important to provide more reliable results when combined with HPLC separations. An adequate sample preparation step before the chromatographic analysis is mandatory in obtaining higher precision and accuracy in order to improve the extraction of the target analytes, one of the priorities in analytical chemistry. The recent discovery of new materials such as ionic liquids, graphene-derived materials, molecularly imprinted polymers, restricted access media, magnetic nanoparticles, and carbonaceous nanomaterials, provided high sensitivity and selectivity results in an extensive variety of applications. These materials, as well as their several possible combinations, have been demonstrated to be highly appropriate for the extraction of different analytes in complex samples such as food products. The main characteristics and application of these new materials in food analysis will be presented and discussed in this paper. Another topic discussed in this review covers the main advantages and limitations of sample preparation microtechniques, as well as their off-line and on-line combination with HPLC for food analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Influence of CeO2 addition on the preparation of foamed glass-ceramics from high-titanium blast furnace slag

    NASA Astrophysics Data System (ADS)

    Zhou, Hong-ling; Feng, Ke-qin; Chen, Chang-hong; Yan, Zi-di

    2018-06-01

    Foamed glass-ceramics doped with cerium oxide (CeO2) were successfully prepared from high-titanium blast furnace slag by one-step sintering. The influence of CeO2 addition (1.5wt%-3.5wt%) on the crystalline phases, microstructure, and properties of foamed glass-ceramics was studied. Results show that CeO2 improves the stability of the glass phase and changes the two-dimensional crystallization mechanism into three-dimensional one. XRD analysis indicates the presence of Ca(Mg, Fe)Si2O6 and Ca(Ti, Mg, Al)(Si, Al)2O6 in all sintered samples. Added with CeO2, TiCeO4 precipitates, and crystallinity increases, leading to increased thickness of pore walls and uniform pores. The comprehensive properties of foamed glass-ceramics are better than that of samples without CeO2. In particular, the sample added with a suitable amount of CeO2 (2.5wt%) exhibits bulk density that is similar to and compressive strength (14.9 MPa) that is more than twice of foamed glass-ceramics without CeO2.

  5. Sample preparation for sequencing hits from one-bead-one-peptide combinatorial libraries by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Martínez-Ceron, María C; Giudicessi, Silvana L; Marani, Mariela M; Albericio, Fernando; Cascone, Osvaldo; Erra-Balsells, Rosa; Camperi, Silvia A

    2010-05-15

    Optimization of bead analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) after the screening of one-bead-one-peptide combinatorial libraries was achieved, involving the fine-tuning of the whole process. Guanidine was replaced by acetonitrile (MeCN)/acetic acid (AcOH)/water (H(2)O), improving matrix crystallization. Peptide-bead cleavage with NH(4)OH was cheaper and safer than, yet as efficient as, NH(3)/tetrahydrofuran (THF). Peptide elution in microtubes instead of placing the beads in the sample plate yielded more sample aliquots. Successive dry layers deposit sample preparation was better than the dried droplet method. Among the matrices analyzed, alpha-cyano-4-hydroxycinnamic acid resulted in the best peptide ion yield. Cluster formation was minimized by the addition of additives to the matrix. Copyright 2010 Elsevier Inc. All rights reserved.

  6. Quantitative and qualitative measure of intralaboratory two-dimensional protein gel reproducibility and the effects of sample preparation, sample load, and image analysis.

    PubMed

    Choe, Leila H; Lee, Kelvin H

    2003-10-01

    We investigate one approach to assess the quantitative variability in two-dimensional gel electrophoresis (2-DE) separations based on gel-to-gel variability, sample preparation variability, sample load differences, and the effect of automation on image analysis. We observe that 95% of spots present in three out of four replicate gels exhibit less than a 0.52 coefficient of variation (CV) in fluorescent stain intensity (% volume) for a single sample run on multiple gels. When four parallel sample preparations are performed, this value increases to 0.57. We do not observe any significant change in quantitative value for an increase or decrease in sample load of 30% when using appropriate image analysis variables. Increasing use of automation, while necessary in modern 2-DE experiments, does change the observed level of quantitative and qualitative variability among replicate gels. The number of spots that change qualitatively for a single sample run in parallel varies from a CV = 0.03 for fully manual analysis to CV = 0.20 for a fully automated analysis. We present a systematic method by which a single laboratory can measure gel-to-gel variability using only three gel runs.

  7. The minimum information required for a glycomics experiment (MIRAGE) project: sample preparation guidelines for reliable reporting of glycomics datasets.

    PubMed

    Struwe, Weston B; Agravat, Sanjay; Aoki-Kinoshita, Kiyoko F; Campbell, Matthew P; Costello, Catherine E; Dell, Anne; Ten Feizi; Haslam, Stuart M; Karlsson, Niclas G; Khoo, Kay-Hooi; Kolarich, Daniel; Liu, Yan; McBride, Ryan; Novotny, Milos V; Packer, Nicolle H; Paulson, James C; Rapp, Erdmann; Ranzinger, Rene; Rudd, Pauline M; Smith, David F; Tiemeyer, Michael; Wells, Lance; York, William S; Zaia, Joseph; Kettner, Carsten

    2016-09-01

    The minimum information required for a glycomics experiment (MIRAGE) project was established in 2011 to provide guidelines to aid in data reporting from all types of experiments in glycomics research including mass spectrometry (MS), liquid chromatography, glycan arrays, data handling and sample preparation. MIRAGE is a concerted effort of the wider glycomics community that considers the adaptation of reporting guidelines as an important step towards critical evaluation and dissemination of datasets as well as broadening of experimental techniques worldwide. The MIRAGE Commission published reporting guidelines for MS data and here we outline guidelines for sample preparation. The sample preparation guidelines include all aspects of sample generation, purification and modification from biological and/or synthetic carbohydrate material. The application of MIRAGE sample preparation guidelines will lead to improved recording of experimental protocols and reporting of understandable and reproducible glycomics datasets. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Optimization and validation of sample preparation for metagenomic sequencing of viruses in clinical samples.

    PubMed

    Lewandowska, Dagmara W; Zagordi, Osvaldo; Geissberger, Fabienne-Desirée; Kufner, Verena; Schmutz, Stefan; Böni, Jürg; Metzner, Karin J; Trkola, Alexandra; Huber, Michael

    2017-08-08

    Sequence-specific PCR is the most common approach for virus identification in diagnostic laboratories. However, as specific PCR only detects pre-defined targets, novel virus strains or viruses not included in routine test panels will be missed. Recently, advances in high-throughput sequencing allow for virus-sequence-independent identification of entire virus populations in clinical samples, yet standardized protocols are needed to allow broad application in clinical diagnostics. Here, we describe a comprehensive sample preparation protocol for high-throughput metagenomic virus sequencing using random amplification of total nucleic acids from clinical samples. In order to optimize metagenomic sequencing for application in virus diagnostics, we tested different enrichment and amplification procedures on plasma samples spiked with RNA and DNA viruses. A protocol including filtration, nuclease digestion, and random amplification of RNA and DNA in separate reactions provided the best results, allowing reliable recovery of viral genomes and a good correlation of the relative number of sequencing reads with the virus input. We further validated our method by sequencing a multiplexed viral pathogen reagent containing a range of human viruses from different virus families. Our method proved successful in detecting the majority of the included viruses with high read numbers and compared well to other protocols in the field validated against the same reference reagent. Our sequencing protocol does work not only with plasma but also with other clinical samples such as urine and throat swabs. The workflow for virus metagenomic sequencing that we established proved successful in detecting a variety of viruses in different clinical samples. Our protocol supplements existing virus-specific detection strategies providing opportunities to identify atypical and novel viruses commonly not accounted for in routine diagnostic panels.

  9. The effects of water sample treatment, preparation, and storage prior to cyanotoxin analysis for cylindrospermopsin, microcystin and saxitoxin.

    PubMed

    Kamp, Lisa; Church, Jennifer L; Carpino, Justin; Faltin-Mara, Erin; Rubio, Fernando

    2016-02-25

    Cyanobacterial harmful algal blooms occur in freshwater lakes, ponds, rivers, and reservoirs, and in brackish waters throughout the world. The wide variety of cyanotoxins and their congeners can lead to frequent exposure of humans through consumption of meat, fish, seafood, blue-green algal products and water, accidental ingestion of contaminated water and cyanobacterial scum during recreational activities, and inhalation of cyanobacterial aerosols. Cyanotoxins can also occur in the drinking water supply. In order to monitor human exposure, sensitive analytical methods such as enzyme linked immunosorbent assay and liquid chromatography-mass spectrometry are often used. Regardless of the analytical method of choice, some problems regularly occur during sample collection, treatment, storage, and preparation which cause toxin loss and therefore underestimation of the true concentration. To evaluate the potential influence of sample treatment, storage and preparation materials on surface and drinking water samples, the effects of different types of materials on toxin recovery were compared. Collection and storage materials included glass and various types of plastics. It was found that microcystin congeners LA and LF adsorbed to polystyrene, polypropylene, high density polyethylene and polycarbonate storage containers, leading to low recoveries (<70%), cylindrospermopsin and saxitoxin did not adsorb to the containers tested. Therefore, this study shows that glass or polyethylene terephthalate glycol containers are the materials of choice for collection and storage of samples containing the cyanotoxins cylindrospermopsin, microcystins, and saxitoxin. This study also demonstrated that after 15 min chlorine decreased the concentration of microcystin LR to <40%, microcystin LA and saxitoxin to <15%, therefore quenching of drinking water samples immediately upon sample collection is critical for accurate analysis. In addition, the effect of various drinking water treatment

  10. Inverse supercritical fluid extraction as a sample preparation method for the analysis of the nanoparticle content in sunscreen agents.

    PubMed

    Müller, David; Cattaneo, Stefano; Meier, Florian; Welz, Roland; de Vries, Tjerk; Portugal-Cohen, Meital; Antonio, Diana C; Cascio, Claudia; Calzolai, Luigi; Gilliland, Douglas; de Mello, Andrew

    2016-04-01

    We demonstrate the use of inverse supercritical carbon dioxide (scCO2) extraction as a novel method of sample preparation for the analysis of complex nanoparticle-containing samples, in our case a model sunscreen agent with titanium dioxide nanoparticles. The sample was prepared for analysis in a simplified process using a lab scale supercritical fluid extraction system. The residual material was easily dispersed in an aqueous solution and analyzed by Asymmetrical Flow Field-Flow Fractionation (AF4) hyphenated with UV- and Multi-Angle Light Scattering detection. The obtained results allowed an unambiguous determination of the presence of nanoparticles within the sample, with almost no background from the matrix itself, and showed that the size distribution of the nanoparticles is essentially maintained. These results are especially relevant in view of recently introduced regulatory requirements concerning the labeling of nanoparticle-containing products. The novel sample preparation method is potentially applicable to commercial sunscreens or other emulsion-based cosmetic products and has important ecological advantages over currently used sample preparation techniques involving organic solvents. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Review of online coupling of sample preparation techniques with liquid chromatography.

    PubMed

    Pan, Jialiang; Zhang, Chengjiang; Zhang, Zhuomin; Li, Gongke

    2014-03-07

    Sample preparation is still considered as the bottleneck of the whole analytical procedure, and efforts has been conducted towards the automation, improvement of sensitivity and accuracy, and low comsuption of organic solvents. Development of online sample preparation techniques (SP) coupled with liquid chromatography (LC) is a promising way to achieve these goals, which has attracted great attention. This article reviews the recent advances on the online SP-LC techniques. Various online SP techniques have been described and summarized, including solid-phase-based extraction, liquid-phase-based extraction assisted with membrane, microwave assisted extraction, ultrasonic assisted extraction, accelerated solvent extraction and supercritical fluids extraction. Specially, the coupling approaches of online SP-LC systems and the corresponding interfaces have been discussed and reviewed in detail, such as online injector, autosampler combined with transport unit, desorption chamber and column switching. Typical applications of the online SP-LC techniques have been summarized. Then the problems and expected trends in this field are attempted to be discussed and proposed in order to encourage the further development of online SP-LC techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Glass sample preparation and performance investigations

    NASA Astrophysics Data System (ADS)

    Johnson, R. Barry

    1992-04-01

    This final report details the work performed under this delivery order from April 1991 through April 1992. The currently available capabilities for integrated optical performance modeling at MSFC for large and complex systems such as AXAF were investigated. The Integrated Structural Modeling (ISM) program developed by Boeing for the U.S. Air Force was obtained and installed on two DECstations 5000 at MSFC. The structural, thermal and optical analysis programs available in ISM were evaluated. As part of the optomechanical engineering activities, technical support was provided in the design of support structure, mirror assembly, filter wheel assembly and material selection for the Solar X-ray Imager (SXI) program. As part of the fabrication activities, a large number of zerodur glass samples were prepared in different sizes and shapes for acid etching, coating and polishing experiments to characterize the subsurface damage and stresses produced by the grinding and polishing operations. Various optical components for AXAF video microscope and the x-ray test facility were also fabricated. A number of glass fabrication and test instruments such as a scatter plate interferometer, a gravity feed saw and some phenolic cutting blades were fabricated, integrated and tested.

  13. Simplified sample preparation method for triclosan and methyltriclosan determination in biota and foodstuff samples.

    PubMed

    Canosa, P; Rodríguez, I; Rubí, E; Ramil, M; Cela, R

    2008-04-25

    An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs.

  14. A sample preparation method for recovering suppressed analyte ions in MALDI TOF MS.

    PubMed

    Lou, Xianwen; de Waal, Bas F M; Milroy, Lech-Gustav; van Dongen, Joost L J

    2015-05-01

    In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS), analyte signals can be substantially suppressed by other compounds in the sample. In this technical note, we describe a modified thin-layer sample preparation method that significantly reduces the analyte suppression effect (ASE). In our method, analytes are deposited on top of the surface of matrix preloaded on the MALDI plate. To prevent embedding of analyte into the matrix crystals, the sample solution were prepared without matrix and efforts were taken not to re-dissolve the preloaded matrix. The results with model mixtures of peptides, synthetic polymers and lipids show that detection of analyte ions, which were completely suppressed using the conventional dried-droplet method, could be effectively recovered by using our method. Our findings suggest that the incorporation of analytes in the matrix crystals has an important contributory effect on ASE. By reducing ASE, our method should be useful for the direct MALDI MS analysis of multicomponent mixtures. Copyright © 2015 John Wiley & Sons, Ltd.

  15. An accurate bacterial DNA quantification assay for HTS library preparation of human biological samples.

    PubMed

    Seashols-Williams, Sarah; Green, Raquel; Wohlfahrt, Denise; Brand, Angela; Tan-Torres, Antonio Limjuco; Nogales, Francy; Brooks, J Paul; Singh, Baneshwar

    2018-05-17

    Sequencing and classification of microbial taxa within forensically relevant biological fluids has the potential for applications in the forensic science and biomedical fields. The quantity of bacterial DNA from human samples is currently estimated based on quantity of total DNA isolated. This method can miscalculate bacterial DNA quantity due to the mixed nature of the sample, and consequently library preparation is often unreliable. We developed an assay that can accurately and specifically quantify bacterial DNA within a mixed sample for reliable 16S ribosomal DNA (16S rDNA) library preparation and high throughput sequencing (HTS). A qPCR method was optimized using universal 16S rDNA primers, and a commercially available bacterial community DNA standard was used to develop a precise standard curve. Following qPCR optimization, 16S rDNA libraries from saliva, vaginal and menstrual secretions, urine, and fecal matter were amplified and evaluated at various DNA concentrations; successful HTS data were generated with as low as 20 pg of bacterial DNA. Changes in bacterial DNA quantity did not impact observed relative abundances of major bacterial taxa, but relative abundance changes of minor taxa were observed. Accurate quantification of microbial DNA resulted in consistent, successful library preparations for HTS analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Simple Sodium Dodecyl Sulfate-Assisted Sample Preparation Method for LC-MS-based Proteomic Applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhou, Jianying; Dann, Geoffrey P.; Shi, Tujin

    2012-03-10

    Sodium dodecyl sulfate (SDS) is one of the most popular laboratory reagents used for highly efficient biological sample extraction; however, SDS presents a significant challenge to LC-MS-based proteomic analyses due to its severe interference with reversed-phase LC separations and electrospray ionization interfaces. This study reports a simple SDS-assisted proteomic sample preparation method facilitated by a novel peptide-level SDS removal protocol. After SDS-assisted protein extraction and digestion, SDS was effectively (>99.9%) removed from peptides through ion substitution-mediated DS- precipitation with potassium chloride (KCl) followed by {approx}10 min centrifugation. Excellent peptide recovery (>95%) was observed for less than 20 {mu}g of peptides.more » Further experiments demonstrated the compatibility of this protocol with LC-MS/MS analyses. The resulting proteome coverage from this SDS-assisted protocol was comparable to or better than those obtained from other standard proteomic preparation methods in both mammalian tissues and bacterial samples. These results suggest that this SDS-assisted protocol is a practical, simple, and broadly applicable proteomic sample processing method, which can be particularly useful when dealing with samples difficult to solubilize by other methods.« less

  17. On the preparation of electron sensor using LiRbSO4 samples

    NASA Astrophysics Data System (ADS)

    El-Muraikhi, M.; Kassem, M. E.; Gaafar, M.; Abdel Gawad, M. M. H.; Ragab, I. M.

    2005-01-01

    The dielectric spectroscopy of metal-metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron energy beams at fixed dose, 0.5 Gy, showed abrupt change of the electrical properties (electrical conductivity, capacitance, and loss tangent). The results can be explained on the basis of radiation-induced defects followed by radiation quenching. The prepared samples can be used in the field of radiation dosimeter.

  18. Automated acoustic matrix deposition for MALDI sample preparation.

    PubMed

    Aerni, Hans-Rudolf; Cornett, Dale S; Caprioli, Richard M

    2006-02-01

    Novel high-throughput sample preparation strategies for MALDI imaging mass spectrometry (IMS) and profiling are presented. An acoustic reagent multispotter was developed to provide improved reproducibility for depositing matrix onto a sample surface, for example, such as a tissue section. The unique design of the acoustic droplet ejector and its optimization for depositing matrix solution are discussed. Since it does not contain a capillary or nozzle for fluid ejection, issues with clogging of these orifices are avoided. Automated matrix deposition provides better control of conditions affecting protein extraction and matrix crystallization with the ability to deposit matrix accurately onto small surface features. For tissue sections, matrix spots of 180-200 microm in diameter were obtained and a procedure is described for generating coordinate files readable by a mass spectrometer to permit automated profile acquisition. Mass spectral quality and reproducibility was found to be better than that obtained with manual pipet spotting. The instrument can also deposit matrix spots in a dense array pattern so that, after analysis in a mass spectrometer, two-dimensional ion images may be constructed. Example ion images from a mouse brain are presented.

  19. Photochemical preparation of olefin addition catalysts

    NASA Technical Reports Server (NTRS)

    Gray, Harry B. (Inventor); Rembaum, Alan (Inventor); Gupta, Amitava (Inventor)

    1978-01-01

    Novel polymer supported catalysts are prepared by photo-irradiation of low valent transition metal compounds such as Co.sub.2 (CO).sub.8, Rh.sub.4 (CO).sub.12 or Ru.sub.3 (CO).sub.12 in the presence of solid polymers containing amine ligands such as polyvinyl pyridine. Hydroformylation of olefins to aldehydes at ambient conditions has been demonstrated.

  20. 40 CFR 270.140 - What else must the Director prepare in addition to the draft RAP or notice of intent to deny?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... addition to the draft RAP or notice of intent to deny? 270.140 Section 270.140 Protection of Environment... the Director prepare in addition to the draft RAP or notice of intent to deny? Once the Director has prepared the draft RAP or notice of intent to deny, he must then: (a) Prepare a statement of basis that...

  1. 40 CFR 270.140 - What else must the Director prepare in addition to the draft RAP or notice of intent to deny?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... addition to the draft RAP or notice of intent to deny? 270.140 Section 270.140 Protection of Environment... the Director prepare in addition to the draft RAP or notice of intent to deny? Once the Director has prepared the draft RAP or notice of intent to deny, he must then: (a) Prepare a statement of basis that...

  2. 40 CFR 270.140 - What else must the Director prepare in addition to the draft RAP or notice of intent to deny?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... addition to the draft RAP or notice of intent to deny? 270.140 Section 270.140 Protection of Environment... the Director prepare in addition to the draft RAP or notice of intent to deny? Once the Director has prepared the draft RAP or notice of intent to deny, he must then: (a) Prepare a statement of basis that...

  3. 40 CFR 270.140 - What else must the Director prepare in addition to the draft RAP or notice of intent to deny?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... addition to the draft RAP or notice of intent to deny? 270.140 Section 270.140 Protection of Environment... the Director prepare in addition to the draft RAP or notice of intent to deny? Once the Director has prepared the draft RAP or notice of intent to deny, he must then: (a) Prepare a statement of basis that...

  4. Automation of sample preparation for mass cytometry barcoding in support of clinical research: protocol optimization.

    PubMed

    Nassar, Ala F; Wisnewski, Adam V; Raddassi, Khadir

    2017-03-01

    Analysis of multiplexed assays is highly important for clinical diagnostics and other analytical applications. Mass cytometry enables multi-dimensional, single-cell analysis of cell type and state. In mass cytometry, the rare earth metals used as reporters on antibodies allow determination of marker expression in individual cells. Barcode-based bioassays for CyTOF are able to encode and decode for different experimental conditions or samples within the same experiment, facilitating progress in producing straightforward and consistent results. Herein, an integrated protocol for automated sample preparation for barcoding used in conjunction with mass cytometry for clinical bioanalysis samples is described; we offer results of our work with barcoding protocol optimization. In addition, we present some points to be considered in order to minimize the variability of quantitative mass cytometry measurements. For example, we discuss the importance of having multiple populations during titration of the antibodies and effect of storage and shipping of labelled samples on the stability of staining for purposes of CyTOF analysis. Data quality is not affected when labelled samples are stored either frozen or at 4 °C and used within 10 days; we observed that cell loss is greater if cells are washed with deionized water prior to shipment or are shipped in lower concentration. Once the labelled samples for CyTOF are suspended in deionized water, the analysis should be performed expeditiously, preferably within the first hour. Damage can be minimized if the cells are resuspended in phosphate-buffered saline (PBS) rather than deionized water while waiting for data acquisition.

  5. Metal retention in human transferrin: consequences of solvent composition in analytical sample preparation methods.

    PubMed

    Quarles, C Derrick; Randunu, K Manoj; Brumaghim, Julia L; Marcus, R Kenneth

    2011-10-01

    The analysis of metal-binding proteins requires careful sample manipulation to ensure that the metal-protein complex remains in its native state and the metal retention is preserved during sample preparation or analysis. Chemical analysis for the metal content in proteins typically involves some type of liquid chromatography/electrophoresis separation step coupled with an atomic (i.e., inductively coupled plasma-optical emission spectroscopy or -mass spectrometry) or molecular (i.e., electrospray ionization-mass spectrometry) analysis step that requires altered-solvent introduction techniques. UV-VIS absorbance is employed here to monitor the iron content in human holo-transferrin (Tf) under various solvent conditions, changing polarity, pH, ionic strength, and the ionic and hydrophobic environment of the protein. Iron loading percentages (i.e. 100% loading equates to 2 Fe(3+):1 Tf) were quantitatively determined to evaluate the effect of solvent composition on the retention of Fe(3+) in Tf. Maximum retention of Fe(3+) was found in buffered (20 mM Tris) solutions (96 ± 1%). Exposure to organic solvents and deionized H(2)O caused release of ~23-36% of the Fe(3+) from the binding pocket(s) at physiological pH (7.4). Salt concentrations similar to separation conditions used for ion exchange had little to no effect on Fe(3+) retention in holo-Tf. Unsurprisingly, changes in ionic strength caused by additions of guanidine HCl (0-10 M) to holo-Tf resulted in unfolding of the protein and loss of Fe(3+) from Tf; however, denaturing and metal loss was found not to be an instantaneous process for additions of 1-5 M guanidinium to Tf. In contrast, complete denaturing and loss of Fe(3+) was instantaneous with ≥6 M additions of guanidinium, and denaturing and loss of iron from Tf occurred in parallel proportions. Changes to the hydrophobicity of Tf (via addition of 0-14 M urea) had less effect on denaturing and release of Fe(3+) from the Tf binding pocket compared to changes

  6. A guide to large-scale RNA sample preparation.

    PubMed

    Baronti, Lorenzo; Karlsson, Hampus; Marušič, Maja; Petzold, Katja

    2018-05-01

    RNA is becoming more important as an increasing number of functions, both regulatory and enzymatic, are being discovered on a daily basis. As the RNA boom has just begun, most techniques are still in development and changes occur frequently. To understand RNA functions, revealing the structure of RNA is of utmost importance, which requires sample preparation. We review the latest methods to produce and purify a variation of RNA molecules for different purposes with the main focus on structural biology and biophysics. We present a guide aimed at identifying the most suitable method for your RNA and your biological question and highlighting the advantages of different methods. Graphical abstract In this review we present different methods for large-scale production and purification of RNAs for structural and biophysical studies.

  7. Advanced Curation Activities at NASA: Preparing to Receive, Process, and Distribute Samples Returned from Future Missions

    NASA Technical Reports Server (NTRS)

    McCubbin, Francis M.; Zeigler, Ryan A.

    2017-01-01

    The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10F JSC is charged with curation of all extraterrestrial material under NASA control, including future NASA missions. The Directive goes on to define Curation as including documentation, preservation, preparation, and distribution of samples for research, education, and public outreach. Here we briefly describe NASA's astromaterials collections and our ongoing efforts related to enhancing the utility of our current collections as well as our efforts to prepare for future sample return missions. We collectively refer to these efforts as advanced curation.

  8. Improvements in soft gelatin capsule sample preparation for USP-based simethicone FTIR analysis.

    PubMed

    Hargis, Amy D; Whittall, Linda B

    2013-02-23

    Due to the absence of a significant chromophore, Simethicone raw material and finished product analysis is achieved using a FTIR-based method that quantifies the polydimethylsiloxane (PDMS) component of the active ingredient. The method can be found in the USP monographs for several dosage forms of Simethicone-containing pharmaceutical products. For soft gelatin capsules, the PDMS assay values determined using the procedure described in the USP method were variable (%RSDs from 2 to 9%) and often lower than expected based on raw material values. After investigation, it was determined that the extraction procedure used for sample preparation was causing loss of material to the container walls due to the hydrophobic nature of PDMS. Evaluation revealed that a simple dissolution of the gelatin capsule fill in toluene provided improved assay results (%RSDs≤0.5%) as well as a simplified and rapid sample preparation. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Applications of Blue Light-curing Acrylic Resin to Forensic Sample Preparation and Microtomy.

    PubMed

    Groves, Ethan; Palenik, Christopher S

    2016-03-01

    This study discusses the results of an evaluation of a one-part blue light-curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light-curing acrylic resins provide the desired properties of an embedding medium, generate high-quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory. © 2015 American Academy of Forensic Sciences.

  10. Sample preparation methods for scanning electron microscopy of homogenized Al-Mg-Si billets: A comparative study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Österreicher, Johannes Albert; Kumar, Manoj

    Characterization of Mg-Si precipitates is crucial for optimizing the homogenization heat treatment of Al-Mg-Si alloys. Although sample preparation is key for high quality scanning electron microscopy imaging, most common methods lead to dealloying of Mg-Si precipitates. In this article we systematically evaluate different sample preparation methods: mechanical polishing, etching with various reagents, and electropolishing using different electrolytes. We demonstrate that the use of a nitric acid and methanol electrolyte for electropolishing a homogenized Al-Mg-Si alloy prevents the dissolution of Mg-Si precipitates, resulting in micrographs of higher quality. This preparation method is investigated in depth and the obtained scanning electron microscopymore » images are compared with transmission electron micrographs: the shape and size of Mg-Si precipitates appear very similar in either method. The scanning electron micrographs allow proper identification and measurement of the Mg-Si phases including needles with lengths of roughly 200 nm. These needles are β″ precipitates as confirmed by high resolution transmission electron microscopy. - Highlights: •Secondary precipitation in homogenized 6xxx Al alloys is crucial for extrudability. •Existing sample preparation methods for SEM are improvable. •Electropolishing with nitric acid/methanol yields superior quality in SEM. •The obtained micrographs are compared to TEM micrographs.« less

  11. Preparation and analysis of standardized waste samples for Controlled Ecological Life Support Systems (CELSS)

    NASA Technical Reports Server (NTRS)

    Carden, J. L.; Browner, R.

    1982-01-01

    The preparation and analysis of standardized waste samples for controlled ecological life support systems (CELSS) are considered. Analysis of samples from wet oxidation experiments, the development of ion chromatographic techniques utilizing conventional high pressure liquid chromatography (HPLC) equipment, and an investigation of techniques for interfacing an ion chromatograph (IC) with an inductively coupled plasma optical emission spectrometer (ICPOES) are discussed.

  12. Microchip Module for Blood Sample Preparation and Nucleic Acid Amplification Reactions

    PubMed Central

    Yuen, Po Ki; Kricka, Larry J.; Fortina, Paolo; Panaro, Nicholas J.; Sakazume, Taku; Wilding, Peter

    2001-01-01

    A computer numerical control-machined plexiglas-based microchip module was designed and constructed for the integration of blood sample preparation and nucleic acid amplification reactions. The microchip module is comprised of a custom-made heater-cooler for thermal cycling, a series of 254 μm × 254 μm microchannels for transporting human whole blood and reagents in and out of an 8–9 μL dual-purpose (cell isolation and PCR) glass-silicon microchip. White blood cells were first isolated from a small volume of human whole blood (<3 μL) in an integrated cell isolation–PCR microchip containing a series of 3.5-μm feature-sized “weir-type” filters, formed by an etched silicon dam spanning the flow chamber. A genomic target, a region in the human coagulation Factor V gene (226-bp), was subsequently directly amplified by microchip-based PCR on DNA released from white blood cells isolated on the filter section of the microchip mounted onto the microchip module. The microchip module provides a convenient means to simplify nucleic acid analyses by integrating two key steps in genetic testing procedures, cell isolation and PCR and promises to be adaptable for additional types of integrated assays. PMID:11230164

  13. Spectrophotometric methods for the determination of urea in real samples using silver nanoparticles by standard addition and 2nd order derivative methods

    NASA Astrophysics Data System (ADS)

    Ali, Nauman; Ismail, Muhammad; Khan, Adnan; Khan, Hamayun; Haider, Sajjad; Kamal, Tahseen

    2018-01-01

    In this work, we have developed simple, sensitive and inexpensive methods for the spectrophotometric determination of urea in urine samples using silver nanoparticles (AgNPs). The standard addition and 2nd order derivative methods were adopted for this purpose. AgNPs were prepared by chemical reduction of AgNO3 with hydrazine using 1,3-di-(1H-imidazol-1-yl)-2-propanol (DIPO) as a stabilizing agent in aqueous medium. The proposed methods were based on the complexation of AgNPs with urea. Using this concept, urea in the urine samples was successfully determined spectrophotometric methods. The results showed high percent recovery with ± RSD. The recoveries of urea in the three urine samples by spectrophotometric standard addition were 99.2% ± 5.37, 96.3% ± 4.49, 104.88% ± 4.99 and that of spectrophotometric 2nd order derivative method were 115.3% ± 5.2, 103.4% ± 2.6, 105.93% ± 0.76. The results show that these methods can open doors for a potential role of AgNPs in the clinical determination of urea in urine, blood, biological, non-biological fluids.

  14. A novel sample preparation method to avoid influence of embedding medium during nano-indentation

    NASA Astrophysics Data System (ADS)

    Meng, Yujie; Wang, Siqun; Cai, Zhiyong; Young, Timothy M.; Du, Guanben; Li, Yanjun

    2013-02-01

    The effect of the embedding medium on the nano-indentation measurements of lignocellulosic materials was investigated experimentally using nano-indentation. Both the reduced elastic modulus and the hardness of non-embedded cell walls were found to be lower than those of the embedded samples, proving that the embedding medium used for specimen preparation on cellulosic material during nano-indentation can modify cell-wall properties. This leads to structural and chemical changes in the cell-wall constituents, changes that may significantly alter the material properties. Further investigation was carried out to detect the influence of different vacuum times on the cell-wall mechanical properties during the embedding procedure. Interpretation of the statistical analysis revealed no linear relationships between vacuum time and the mechanical properties of cell walls. The quantitative measurements confirm that low-viscosity resin has a rapid penetration rate early in the curing process. Finally, a novel sample preparation method aimed at preventing resin diffusion into lignocellulosic cell walls was developed using a plastic film to wrap the sample before embedding. This method proved to be accessible and straightforward for many kinds of lignocellulosic material, but is especially suitable for small, soft samples.

  15. Effect of sample preparation method on quantification of polymorphs using PXRD.

    PubMed

    Alam, Shahnwaz; Patel, Sarsvatkumar; Bansal, Arvind Kumar

    2010-01-01

    The purpose of this study was to improve the sensitivity and accuracy of quantitative analysis of polymorphic mixtures. Various techniques such as hand grinding and mixing (in mortar and pestle), air jet milling and ball milling for micronization of particle and mixing were used to prepare binary mixtures. Using these techniques, mixtures of form I and form II of clopidogrel bisulphate were prepared in various proportions from 0-5% w/w of form I in form II and subjected to x-ray powder diffraction analysis. In order to obtain good resolution in minimum time, step time and step size were varied to optimize scan rate. Among the six combinations, step size of 0.05 degrees with step time of 5 s demonstrated identification of maximum characteristic peaks of form I in form II. Data obtained from samples prepared using both grinding and mixing in ball mill showed good analytical sensitivity and accuracy compared to other methods. Powder x-ray diffraction method was reproducible, precise with LOD of 0.29% and LOQ of 0.91%. Validation results showed excellent correlation between actual and predicted concentration with R2 > 0.9999.

  16. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING AIR SAMPLES FOR ANALYSIS OF POLAR PERSISTENT ORGANIC POLLUTANTS (SOP-5.13)

    EPA Science Inventory

    The method for extracting and preparing indoor and outdoor air samples for analysis of polar persistent organic pollutants is summarized in this SOP. It covers the preparation of samples that are to be analyzed by gas chromatography/mass spectrometry.

  17. Community-Level Physiological Profiling of Microbial Communities in Constructed Wetlands: Effects of Sample Preparation.

    PubMed

    Button, Mark; Weber, Kela; Nivala, Jaime; Aubron, Thomas; Müller, Roland Arno

    2016-03-01

    Community-level physiological profiling (CLPP) using BIOLOG® EcoPlates™ has become a popular method for characterizing and comparing the functional diversity, functional potential, and metabolic activity of heterotrophic microbial communities. The method was originally developed for profiling soil communities; however, its usage has expanded into the fields of ecotoxicology, agronomy, and the monitoring and profiling of microbial communities in various wastewater treatment systems, including constructed wetlands for water pollution control. When performing CLPP on aqueous samples from constructed wetlands, a wide variety of sample characteristics can be encountered and challenges may arise due to excessive solids, color, or turbidity. The aim of this study was to investigate the impacts of different sample preparation methods on CLPP performed on a variety of aqueous samples covering a broad range of physical and chemical characteristics. The results show that using filter paper, centrifugation, or settling helped clarify samples for subsequent CLPP analysis, however did not do so as effectively as dilution for the darkest samples. Dilution was able to provide suitable clarity for the darkest samples; however, 100-fold dilution significantly affected the carbon source utilization patterns (CSUPs), particularly with samples that were already partially or fully clear. Ten-fold dilution also had some effect on the CSUPs of samples which were originally clear; however, the effect was minimal. Based on these findings, for this specific set of samples, a 10-fold dilution provided a good balance between ease of use, sufficient clarity (for dark samples), and limited effect on CSUPs. The process and findings outlined here can hopefully serve future studies looking to utilize CLPP for functional analysis of microbial communities and also assist in comparing data from studies where different sample preparation methods were utilized.

  18. Polysialylated N-Glycans Identified in Human Serum Through Combined Developments in Sample Preparation, Separations and Electrospray ionization-mass spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kronewitter, Scott R.; Marginean, Ioan; Cox, Jonathan T.

    The N-glycan diversity of human serum glycoproteins, i.e. the human blood serum N-glycome, is complex due to the range of glycan structures potentially synthesizable by human glycosylation enzymes. The reported glycome, however, is limited by methods of sample preparation, available analytical platforms, e.g., based upon electrospray ionization-mass spectrometry (ESI-MS), and software tools for data analysis. In this report, several improvements have been implemented in sample preparation and analysis to extend ESI-MS glycan characterization and to provide an improved view of glycan diversity. Sample preparation improvements include acidified, microwave-accelerated, PNGase F N-glycan release, and sodium borohydride reduction were optimized to improvemore » quantitative yields and conserve the number of glycoforms detected. Two-stage desalting (during solid phase extraction and on the analytical column) increased the sensitivity by reducing analyte signal division between multiple reducing-end-forms or cation adducts. On-line separations were improved by using extended length graphitized carbon columns and adding TFA as an acid modifier to a formic acid/reversed phase gradient which provides additional resolving power and significantly improved desorption of both large and heavily sialylated glycans. To improve MS sensitivity and provide gentler ionization conditions at the source-MS interface, subambient pressure ionization with nanoelectrospray (SPIN) has been utilized. When method improvements are combined together with the Glycomics Quintavariate Informed Quantification (GlyQ-IQ) recently described1 these technologies demonstrate the ability to significantly extend glycan detection sensitivity and provide expanded glycan coverage. We demonstrate application of these advances in the context of the human serum glycome, and for which our initial observations include detection of a new class of heavily sialylated N-glycans, including polysialylated N-glycans.« less

  19. Surface Modified Particles By Multi-Step Michael-Type Addition And Process For The Preparation Thereof

    DOEpatents

    Cook, Ronald Lee; Elliott, Brian John; Luebben, Silvia DeVito; Myers, Andrew William; Smith, Bryan Matthew

    2005-05-03

    A new class of surface modified particles and a multi-step Michael-type addition surface modification process for the preparation of the same is provided. The multi-step Michael-type addition surface modification process involves two or more reactions to compatibilize particles with various host systems and/or to provide the particles with particular chemical reactivities. The initial step comprises the attachment of a small organic compound to the surface of the inorganic particle. The subsequent steps attach additional compounds to the previously attached organic compounds through reactive organic linking groups. Specifically, these reactive groups are activated carbon—carbon pi bonds and carbon and non-carbon nucleophiles that react via Michael or Michael-type additions.

  20. Ultrasound: a subexploited tool for sample preparation in metabolomics.

    PubMed

    Luque de Castro, M D; Delgado-Povedano, M M

    2014-01-02

    Metabolomics, one of the most recently emerged "omics", has taken advantage of ultrasound (US) to improve sample preparation (SP) steps. The metabolomics-US assisted SP step binomial has experienced a dissimilar development that has depended on the area (vegetal or animal) and the SP step. Thus, vegetal metabolomics and US assisted leaching has received the greater attention (encompassing subdisciplines such as metallomics, xenometabolomics and, mainly, lipidomics), but also liquid-liquid extraction and (bio)chemical reactions in metabolomics have taken advantage of US energy. Also clinical and animal samples have benefited from US assisted SP in metabolomics studies but in a lesser extension. The main effects of US have been shortening of the time required for the given step, and/or increase of its efficiency or availability for automation; nevertheless, attention paid to potential degradation caused by US has been scant or nil. Achievements and weak points of the metabolomics-US assisted SP step binomial are discussed and possible solutions to the present shortcomings are exposed. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Microfluidic DNA sample preparation method and device

    DOEpatents

    Krulevitch, Peter A.; Miles, Robin R.; Wang, Xiao-Bo; Mariella, Raymond P.; Gascoyne, Peter R. C.; Balch, Joseph W.

    2002-01-01

    Manipulation of DNA molecules in solution has become an essential aspect of genetic analyses used for biomedical assays, the identification of hazardous bacterial agents, and in decoding the human genome. Currently, most of the steps involved in preparing a DNA sample for analysis are performed manually and are time, labor, and equipment intensive. These steps include extraction of the DNA from spores or cells, separation of the DNA from other particles and molecules in the solution (e.g. dust, smoke, cell/spore debris, and proteins), and separation of the DNA itself into strands of specific lengths. Dielectrophoresis (DEP), a phenomenon whereby polarizable particles move in response to a gradient in electric field, can be used to manipulate and separate DNA in an automated fashion, considerably reducing the time and expense involved in DNA analyses, as well as allowing for the miniaturization of DNA analysis instruments. These applications include direct transport of DNA, trapping of DNA to allow for its separation from other particles or molecules in the solution, and the separation of DNA into strands of varying lengths.

  2. Stabilometer "S" value comparison using anti-stripping additives.

    DOT National Transportation Integrated Search

    1985-07-01

    from January through July, 1985, asphalt mixes from five construction projects, with and without an anti-stripping additive, were compared for stability. Ten mix samples for each project, at varying asphalt cement content, were prepared and tested in...

  3. Efficient sample preparation method based on solvent-assisted dispersive solid-phase extraction for the trace detection of butachlor in urine and waste water samples.

    PubMed

    Aladaghlo, Zolfaghar; Fakhari, Alireza; Behbahani, Mohammad

    2016-10-01

    In this work, an efficient sample preparation method termed solvent-assisted dispersive solid-phase extraction was applied. The used sample preparation method was based on the dispersion of the sorbent (benzophenone) into the aqueous sample to maximize the interaction surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by inserting a solution of the sorbent and disperser solvent into the aqueous sample. The cloudy solution created from the dispersion of the sorbent in the bulk aqueous sample. After pre-concentration of the butachlor, the cloudy solution was centrifuged and butachlor in the sediment phase dissolved in ethanol and determined by gas chromatography with flame ionization detection. Under the optimized conditions (solution pH = 7.0, sorbent: benzophenone, 2%, disperser solvent: ethanol, 500 μL, centrifuged at 4000 rpm for 3 min), the method detection limit for butachlor was 2, 3 and 3 μg/L for distilled water, waste water, and urine sample, respectively. Furthermore, the preconcentration factor was 198.8, 175.0, and 174.2 in distilled water, waste water, and urine sample, respectively. Solvent-assisted dispersive solid-phase extraction was successfully used for the trace monitoring of butachlor in urine and waste water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Preparative isolation of flavonoid glycosides from Sphaerophysa salsula using hydrophilic interaction solid-phase extraction coupled with two-dimensional preparative liquid chromatography.

    PubMed

    Jiao, Lijin; Tao, Yanduo; Wang, Weidong; Shao, Yun; Mei, Lijuan; Wang, Qilan; Dang, Jun

    2017-10-01

    An offline preparative two-dimensional reversed-phase liquid chromatography/hydrophilic interaction liquid chromatography coupled with hydrophilic interaction solid-phase extraction method was developed for the preparative isolation of flavonoid glycosides from a crude sample of Sphaerophysa salsula. First, the non-flavonoids were removed using an XAmide solid-phase extraction cartridge. Based on the separation results of three different chromatographic stationary phases, the first-dimensional preparation was performed on an XAqua C18 prep column, and 15 fractions were obtained from the 5.2 g target sample. Then, three representative fractions were selected for additional purification on an XAmide preparative column to further isolate the flavonoid glycosides. In all, eight flavonoid glycosides were isolated in purities over 97%. The results demonstrated that the two-dimensional liquid chromatography method used in this study was effective for the preparative separation of flavonoid glycosides from Sphaerophysa salsula. Additionally, this method showed great potential for the separation of flavonoid glycosides from other plant materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Titanate nanotube thin films with enhanced thermal stability and high-transparency prepared from additive-free sols

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Koroesi, Laszlo, E-mail: korosi@enviroinvest.hu; Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertvaros utca 2, H-7632 Pecs; Papp, Szilvia

    2012-08-15

    Titanate nanotubes were synthesized from TiO{sub 2} in alkaline medium by a conventional hydrothermal method (150 Degree-Sign C, 4.7 bar). To obtain hydrogen titanates, the as-prepared sodium titanates were treated with either HCl or H{sub 3}PO{sub 4} aqueous solutions. A simple synthesis procedure was devised for stable titanate nanotube sols without using any additives. These highly stable ethanolic sols can readily be used to prepare transparent titanate nanotube thin films of high quality. The resulting samples were studied by X-ray diffraction, N{sub 2}-sorption measurements, Raman spectroscopy, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The comparative resultsmore » of using two kinds of acids shed light on the superior thermal stability of the H{sub 3}PO{sub 4}-treated titanate nanotubes (P-TNTs). X-ray photoelectron spectroscopy revealed that P-TNTs contains P in the near-surface region and the thermal stability was enhanced even at a low ({approx}0.5 at%) concentration of P. After calcination at 500 Degree-Sign C, the specific surface areas of the HCl- and H{sub 3}PO{sub 4}-treated samples were 153 and 244 m{sup 2} g{sup -1}, respectively. The effects of H{sub 3}PO{sub 4} treatment on the structure, morphology and porosity of titanate nanotubes are discussed. - Graphical Abstract: TEM picture (left) shows P-TNTs with diameters about 5-6 nm. Inset shows a stable titanate nanotube sol illuminated by a 532 nm laser beam. Due to the presence of the nanoparticles the way of the light is visible in the sol. Cross sectional SEM picture (right) as well as ellipsometry revealed the formation of optical quality P-TNT films with thicknesses below 50 nm. Highlights: Black-Right-Pointing-Pointer H{sub 3}PO{sub 4} treatment led to TNTs with high surface area even after calcination at 500 Degree-Sign C. Black-Right-Pointing-Pointer H{sub 3}PO{sub 4}-treated TNTs preserved their nanotube morphology up

  6. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, D.D.

    A method and apparatus are described for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  7. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-01-01

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  8. Method and apparatus for the preparation of liquid samples for determination of boron

    DOEpatents

    Siemer, Darryl D.

    1986-03-04

    A method and apparatus for the preparation of a liquid sample for the quantitative determination of boron by flame photometry. The sample is combined in a vessel with sulfuric acid, and an excess of methanol is added thereto. The methanol reacts with any boron present in the sample to form trimethyl borate which is volatilized by the heat of reaction between the excess methanol and sulfuric acid. The volatilized trimethyl borate is withdrawn from the vessel by either a partial vacuum or a positive pressure and is rapidly transferred to a standard flame photometer. The method is free of interference from typical boron concomitants.

  9. Error baseline rates of five sample preparation methods used to characterize RNA virus populations.

    PubMed

    Kugelman, Jeffrey R; Wiley, Michael R; Nagle, Elyse R; Reyes, Daniel; Pfeffer, Brad P; Kuhn, Jens H; Sanchez-Lockhart, Mariano; Palacios, Gustavo F

    2017-01-01

    Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic "no amplification" method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a "targeted" amplification method, sequence-independent single-primer amplification (SISPA) as a "random" amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced "no amplification" method, and Illumina TruSeq RNA Access as a "targeted" enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4-5) of all compared methods.

  10. Error baseline rates of five sample preparation methods used to characterize RNA virus populations

    PubMed Central

    Kugelman, Jeffrey R.; Wiley, Michael R.; Nagle, Elyse R.; Reyes, Daniel; Pfeffer, Brad P.; Kuhn, Jens H.; Sanchez-Lockhart, Mariano; Palacios, Gustavo F.

    2017-01-01

    Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic “no amplification” method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a “targeted” amplification method, sequence-independent single-primer amplification (SISPA) as a “random” amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced “no amplification” method, and Illumina TruSeq RNA Access as a “targeted” enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4−5) of all compared methods. PMID:28182717

  11. A "three-in-one" sample preparation method for simultaneous determination of B-group water-soluble vitamins in infant formula using VitaFast(®) kits.

    PubMed

    Zhang, Heng; Lan, Fang; Shi, Yupeng; Wan, Zhi-Gang; Yue, Zhen-Feng; Fan, Fang; Lin, Yan-Kui; Tang, Mu-Jin; Lv, Jing-Zhang; Xiao, Tan; Yi, Changqing

    2014-06-15

    VitaFast(®) test kits designed for the microbiological assay in microtiter plate format can be applied to quantitative determination of B-group water-soluble vitamins such as vitamin B12, folic acid and biotin, et al. Compared to traditional microbiological methods, VitaFast(®) kits significantly reduce sample processing time and provide greater reliability, higher productivity and better accuracy. Recently, simultaneous determination of vitamin B12, folic acid and biotin in one sample is urgently required when evaluating the quality of infant formulae in our practical work. However, the present sample preparation protocols which are developed for individual test systems, are incompatible with simultaneous determination of several analytes. To solve this problem, a novel "three-in-one" sample preparation method is herein developed for simultaneous determination of B-group water-soluble vitamins using VitaFast(®) kits. The performance of this novel "three-in-one" sample preparation method was systematically evaluated through comparing with individual sample preparation protocols. The experimental results of the assays which employed "three-in-one" sample preparation method were in good agreement with those obtained from conventional VitaFast(®) extraction methods, indicating that the proposed "three-in-one" sample preparation method is applicable to the present three VitaFast(®) vitamin test systems, thus offering a promising alternative for the three independent sample preparation methods. The proposed new sample preparation method will significantly improve the efficiency of infant formulae inspection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Multifunctional sample preparation kit and on-chip quantitative nucleic acid sequence-based amplification tests for microbial detection.

    PubMed

    Zhao, Xinyan; Dong, Tao

    2012-10-16

    This study reports a quantitative nucleic acid sequence-based amplification (Q-NASBA) microfluidic platform composed of a membrane-based sampling module, a sample preparation cassette, and a 24-channel Q-NASBA chip for environmental investigations on aquatic microorganisms. This low-cost and highly efficient sampling module, having seamless connection with the subsequent steps of sample preparation and quantitative detection, is designed for the collection of microbial communities from aquatic environments. Eight kinds of commercial membrane filters are relevantly analyzed using Saccharomyces cerevisiae, Escherichia coli, and Staphylococcus aureus as model microorganisms. After the microorganisms are concentrated on the membrane filters, the retentate can be easily conserved in a transport medium (TM) buffer and sent to a remote laboratory. A Q-NASBA-oriented sample preparation cassette is originally designed to extract DNA/RNA molecules directly from the captured cells on the membranes. Sequentially, the extract is analyzed within Q-NASBA chips that are compatible with common microplate readers in laboratories. Particularly, a novel analytical algorithmic method is developed for simple but robust on-chip Q-NASBA assays. The reported multifunctional microfluidic system could detect a few microorganisms quantitatively and simultaneously. Further research should be conducted to simplify and standardize ecological investigations on aquatic environments.

  13. Human urine as test material in 1H NMR-based metabonomics: recommendations for sample preparation and storage.

    PubMed

    Lauridsen, Michael; Hansen, Steen H; Jaroszewski, Jerzy W; Cornett, Claus

    2007-02-01

    Metabonomic approaches are believed to have the capability of revolutionizing diagnosis of diseases and assessment of patient conditions after medical interventions. In order to ensure comparability of metabonomic 1H NMR data from different studies, we suggest validated sample preparation guidelines for human urine based on a stability study that evaluates effects of storage time and temperature, freeze-drying, and the presence of preservatives. The results indicated that human urine samples should be stored at or below -25 degrees C, as no changes in the 1H NMR fingerprints have been observed during storage at this temperature for 26 weeks. Formation of acetate, presumably due to microbial contamination, was occasionally observed in samples stored at 4 degrees C without addition of a preservative. Addition of a preserving agent is not mandatory provided that the samples are stored at -25 degrees C. Thus, no differences were observed between 1H NMR spectra of nonpreserved urines and urines with added sodium azide and stored at -25 degrees C, whereas the presence of sodium fluoride caused a shift of especially citrate resonances. Freeze-drying of urine and reconstitution in D2O at pH 7.4 resulted in the disappearance of the creatinine CH2 signal at delta 4.06 due to deuteration. A study evaluating the effects of phosphate buffer concentration on signal variability and assessment of the probability of citrate or creatinine resonances crossing bucket border (a boundary between adjacent integrated regions) led to the conclusion that a minimum buffer concentration of 0.3 M is adequate for normal urines used in this study. However, final buffer concentration of 1 M will be required for very concentrated urines.

  14. Semiautomated Sample Preparation for Protein Stability and Formulation Screening via Buffer Exchange.

    PubMed

    Ying, William; Levons, Jaquan K; Carney, Andrea; Gandhi, Rajesh; Vydra, Vicky; Rubin, A Erik

    2016-06-01

    A novel semiautomated buffer exchange process workflow was developed to enable efficient early protein formulation screening. An antibody fragment protein, BMSdab, was used to demonstrate the workflow. The process afforded 60% to 80% cycle time and scientist time savings and significant material efficiencies. These efficiencies ultimately facilitated execution of this stability work earlier in the drug development process, allowing this tool to inform the developability of potential candidates for development from a formulation perspective. To overcome the key technical challenges, the protein solution was buffer-exchanged by centrifuge filtration into formulations for stability screening in a 96-well plate with an ultrafiltration membrane, leveraging automated liquid handling and acoustic volume measurements to allow several cycles of exchanges. The formulations were transferred into a vacuum manifold and sterile filtered into a rack holding 96 glass vials. The vials were sealed with a capmat of individual caps and placed in stability stations. Stability of the samples prepared by this process and by the standard process was demonstrated to be comparable. This process enabled screening a number of formulations of a protein at an early pharmaceutical development stage with a short sample preparation time. © 2015 Society for Laboratory Automation and Screening.

  15. Demonstration of the ExoMars sample preparation and distribution system jointly with an optical instrument head

    NASA Astrophysics Data System (ADS)

    Schulte, Wolfgang; Thiele, Hans; Hofmann, Peter; Baglioni, Pietro

    The ExoMars program will search for past and present life on Mars. ExoMars will address important scientific goals and demonstrate key in-situ enabling technologies. Among such technologies are the acquisition, preparation, distribution and analysis of samples from Mars surface rocks and from the subsurface. The 2018 mission will land an ESA rover on Mars which carries a sample preparation and distribution system (SPDS) and a suite of analytical instruments, the Pasteur Payload with its Analytical Laboratory Drawer (ALD). Kayser-Threde GmbH (Germany) will be responsible for the SPDS as a subcontractor under the mission prime Thales Alenia Space. The SPDS comprises a number of complex mechanisms and mechanical devices designed to transport drill core samples within the rover analytical laboratory, to crush them to powder with a fine grain size, to portion discrete amounts of powdered sample material, to distribute and fill the material into sample containers and to prepare flat sample surfaces for scientific analysis. Breadboards of the crushing mechanism, the dosing mechanism and a distribution carousel with sample containers and a powder sample surface flattening mechanism were built and tested. Kayser-Threde, as a member of the Spanish led ExoMars Raman Instrument team, is also responsible for development of the Raman optical head, which will be mounted inside ALD and will inspect the crushed samples, when they are presented to the instrument by the distribution carousel. Within this activity, which is performed under contract with the Institute of Physical Chemistry of the University of Jena (Germany) and funded by the German DLR, Kayser-Threde can demonstrate Raman measurements with the optical head and a COTS laser and spectrometer and thus simulate the full Raman instrument optical path. An autofocus system with actuator and feedback optics is also part of this activity, which allows focusing the 50 m Raman spot on the surface of the powdered sample

  16. Preparation of titanium phosphates with additives in hydrothermal process and their powder properties for cosmetics.

    PubMed

    Onoda, Hiroaki; Yamaguchi, Taisuke

    2013-04-01

    In this study, titanium phosphates were prepared from titanium chloride and phosphoric acid, sodium pyrophosphate and sodium triphosphate solutions with water retention compounds in hydrothermal process as a novel white pigment for cosmetics. Their chemical composition, powder properties, photo catalytic activity, water retention and smoothness were studied. The addition of glycerin in the preparation from sodium pyrophosphate has the useful method to obtain homogenized spherical particles of titanium phosphate pigments for the cosmetics. These titanium phosphates had less photo catalytic activity to protect the sebum on the skin. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  17. The Successful Diagnosis and Typing of Systemic Amyloidosis Using A Microwave-Assisted Filter-Aided Fast Sample Preparation Method and LC/MS/MS Analysis

    PubMed Central

    Zou, Lili; Shen, Kaini; Zhong, Dingrong; Zhou, Daobin; Sun, Wei; Li, Jian

    2015-01-01

    Laser microdissection followed by mass spectrometry has been successfully used for amyloid typing. However, sample contamination can interfere with proteomic analysis, and overnight digestion limits the analytical throughput. Moreover, current quantitative analysis methods are based on the spectrum count, which ignores differences in protein length and may lead to misdiagnoses. Here, we developed a microwave-assisted filter-aided sample preparation (maFASP) method that can efficiently remove contaminants with a 10-kDa cutoff ultrafiltration unit and can accelerate the digestion process with the assistance of a microwave. Additionally, two parameters (P- and D-scores) based on the exponentially modified protein abundance index were developed to define the existence of amyloid deposits and those causative proteins with the greatest abundance. Using our protocol, twenty cases of systemic amyloidosis that were well-typed according to clinical diagnostic standards (training group) and another twenty-four cases without subtype diagnoses (validation group) were analyzed. Using this approach, sample preparation could be completed within four hours. We successfully subtyped 100% of the cases in the training group, and the diagnostic success rate in the validation group was 91.7%. This maFASP-aided proteomic protocol represents an efficient approach for amyloid diagnosis and subtyping, particularly for serum-contaminated samples. PMID:25984759

  18. A high-throughput robotic sample preparation system and HPLC-MS/MS for measuring urinary anatabine, anabasine, nicotine and major nicotine metabolites.

    PubMed

    Wei, Binnian; Feng, June; Rehmani, Imran J; Miller, Sharyn; McGuffey, James E; Blount, Benjamin C; Wang, Lanqing

    2014-09-25

    Most sample preparation methods characteristically involve intensive and repetitive labor, which is inefficient when preparing large numbers of samples from population-scale studies. This study presents a robotic system designed to meet the sampling requirements for large population-scale studies. Using this robotic system, we developed and validated a method to simultaneously measure urinary anatabine, anabasine, nicotine and seven major nicotine metabolites: 4-Hydroxy-4-(3-pyridyl)butanoic acid, cotinine-N-oxide, nicotine-N-oxide, trans-3'-hydroxycotinine, norcotinine, cotinine and nornicotine. We analyzed robotically prepared samples using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry in positive electrospray ionization mode using scheduled multiple reaction monitoring (sMRM) with a total runtime of 8.5 min. The optimized procedure was able to deliver linear analyte responses over a broad range of concentrations. Responses of urine-based calibrators delivered coefficients of determination (R(2)) of >0.995. Sample preparation recovery was generally higher than 80%. The robotic system was able to prepare four 96-well plate (384 urine samples) per day, and the overall method afforded an accuracy range of 92-115%, and an imprecision of <15.0% on average. The validation results demonstrate that the method is accurate, precise, sensitive, robust, and most significantly labor-saving for sample preparation, making it efficient and practical for routine measurements in large population-scale studies such as the National Health and Nutrition Examination Survey (NHANES) and the Population Assessment of Tobacco and Health (PATH) study. Published by Elsevier B.V.

  19. 31. VIEW FROM SOUTHWEST TO CORNER WHERE SAMPLING/CRUSHING ADDITIONS ABUT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VIEW FROM SOUTHWEST TO CORNER WHERE SAMPLING/CRUSHING ADDITIONS ABUT CRUSHED OXIDIZED ORE BIN. INTACT BARREN SOLUTION TANK VISIBLE IN FRONT OF CRUSHED ORE BIN. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  20. Effect of Minor Titanium Addition on Copper/Diamond Composites Prepared by Hot Forging

    NASA Astrophysics Data System (ADS)

    Yang, Fei; Sun, Wei; Singh, Ajit; Bolzoni, Leandro

    2018-03-01

    Copper/diamond composites have great potential to lead the next generation of advanced heat sink materials for use in high-power electronic devices and high-density integrated circuits because of their potential excellent properties of high thermal conductivity and close thermal expansion to the chip materials (e.g., Si, InP, GaAs). However, the poor wettability between copper and diamond presents a challenge for synthesizing copper/diamond composites with effective metallurgical bonding and satisfied thermal performance. In this article, copper/diamond composites were successfully prepared by hot forging of elemental copper and artificial diamond powders with small amounts (0 vol.%, 3 vol.% and 5 vol.%) of titanium additives. Microstructure observation and mechanical tests showed that adding minor titanium additions in the copper/diamond composite resulted in fewer cracks in the composites' microstructure and significantly improved the bonding between the copper and diamond. The strongest bonding strength was achieved for the copper/diamond composite with 3 vol.% titanium addition, and the possible reasons were discussed.

  1. Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cary, Robert E.

    2015-12-08

    Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.

  2. Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cary, Robert B.

    Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.

  3. Comparative Evaluation of Small Molecular Additives and Their Effects on Peptide/Protein Identification.

    PubMed

    Gao, Jing; Zhong, Shaoyun; Zhou, Yanting; He, Han; Peng, Shuying; Zhu, Zhenyun; Liu, Xing; Zheng, Jing; Xu, Bin; Zhou, Hu

    2017-06-06

    Detergents and salts are widely used in lysis buffers to enhance protein extraction from biological samples, facilitating in-depth proteomic analysis. However, these detergents and salt additives must be efficiently removed from the digested samples prior to LC-MS/MS analysis to obtain high-quality mass spectra. Although filter-aided sample preparation (FASP), acetone precipitation (AP), followed by in-solution digestion, and strong cation exchange-based centrifugal proteomic reactors (CPRs) are commonly used for proteomic sample processing, little is known about their efficiencies at removing detergents and salt additives. In this study, we (i) developed an integrative workflow for the quantification of small molecular additives in proteomic samples, developing a multiple reaction monitoring (MRM)-based LC-MS approach for the quantification of six additives (i.e., Tris, urea, CHAPS, SDS, SDC, and Triton X-100) and (ii) systematically evaluated the relationships between the level of additive remaining in samples following sample processing and the number of peptides/proteins identified by mass spectrometry. Although FASP outperformed the other two methods, the results were complementary in terms of peptide/protein identification, as well as the GRAVY index and amino acid distributions. This is the first systematic and quantitative study of the effect of detergents and salt additives on protein identification. This MRM-based approach can be used for an unbiased evaluation of the performance of new sample preparation methods. Data are available via ProteomeXchange under identifier PXD005405.

  4. Quantitative Analysis of Heavy Metals in Water Based on LIBS with an Automatic Device for Sample Preparation

    NASA Astrophysics Data System (ADS)

    Hu, Li; Zhao, Nanjing; Liu, Wenqing; Meng, Deshuo; Fang, Li; Wang, Yin; Yu, Yang; Ma, Mingjun

    2015-08-01

    Heavy metals in water can be deposited on graphite flakes, which can be used as an enrichment method for laser-induced breakdown spectroscopy (LIBS) and is studied in this paper. The graphite samples were prepared with an automatic device, which was composed of a loading and unloading module, a quantitatively adding solution module, a rapid heating and drying module and a precise rotating module. The experimental results showed that the sample preparation methods had no significant effect on sample distribution and the LIBS signal accumulated in 20 pulses was stable and repeatable. With an increasing amount of the sample solution on the graphite flake, the peak intensity at Cu I 324.75 nm accorded with the exponential function with a correlation coefficient of 0.9963 and the background intensity remained unchanged. The limit of detection (LOD) was calculated through linear fitting of the peak intensity versus the concentration. The LOD decreased rapidly with an increasing amount of sample solution until the amount exceeded 20 mL and the correlation coefficient of exponential function fitting was 0.991. The LOD of Pb, Ni, Cd, Cr and Zn after evaporating different amounts of sample solution on the graphite flakes was measured and the variation tendency of their LOD with sample solution amounts was similar to the tendency for Cu. The experimental data and conclusions could provide a reference for automatic sample preparation and heavy metal in situ detection. supported by National Natural Science Foundation of China (No. 60908018), National High Technology Research and Development Program of China (No. 2013AA065502) and Anhui Province Outstanding Youth Science Fund of China (No. 1108085J19)

  5. Improved chip design for integrated solid-phase microextraction in on-line proteomic sample preparation.

    PubMed

    Bergkvist, Jonas; Ekström, Simon; Wallman, Lars; Löfgren, Mikael; Marko-Varga, György; Nilsson, Johan; Laurell, Thomas

    2002-04-01

    A recently introduced silicon microextraction chip (SMEC), used for on-line proteomic sample preparation, has proved to facilitate the process of protein identification by sample clean up and enrichment of peptides. It is demonstrated that a novel grid-SMEC design improves the operating characteristics for solid-phase microextraction, by reducing dispersion effects and thereby improving the sample preparation conditions. The structures investigated in this paper are treated both numerically and experimentally. The numerical approach is based on finite element analysis of the microfluidic flow in the microchip. The analysis is accomplished by use of the computational fluid dynamics-module FLOTRAN in the ANSYS software package. The modeling and analysis of the previously reported weir-SMEC design indicates some severe drawbacks, that can be reduced by changing the microextraction chip geometry to the grid-SMEC design. The overall analytical performance was thereby improved and also verified by experimental work. Matrix-assisted laser desorption/ionization mass spectra of model peptides extracted from both the weir-SMEC and the new grid-SMEC support the numerical analysis results. Further use of numerical modeling and analysis of the SMEC structures is also discussed and suggested in this work.

  6. Effect of additive solutions on red blood cell (RBC) membrane properties of stored RBCs prepared from whole blood held for 24 hours at room temperature.

    PubMed

    Veale, Margaret F; Healey, Gerry; Sparrow, Rosemary L

    2011-01-01

    The quality of RBC components is influenced by collection, processing and storage conditions. Regulations require that whole blood (WB) units be refrigerated within 8 hours and processed into RBCs within 24 hours of collection. Overnight room temperature hold of WB has logistical advantages, but the effect on RBC quality has not been fully investigated. RBC additive solutions were compared for their ability to provide improved quality of RBCs prepared from WB held at room temperature for 24 hours. Leukocyte-reduced RBCs were prepared from WB held at 20°C on cooling plates for 24 hours prior to processing. RBCs were stored in additive solutions, SAG-M (control), Erythrosol-4, and PAGGSM, under standard blood banking conditions and sampled during 49 days of storage. Stored RBCs were evaluated for RBC shape and microparticle (MP) accumulation using flow cytometry. Osmotic fragility, adhesion of RBCs to endothelium under shear stress conditions (0.5 dyne/cm(2) ), and routine RBC quality parameters were assessed. RBCs stored in Erythrosol-4 and PAGGSM had decreased cell size, reduced osmotic fragility, and decreased accumulation of glycophorin A-positive MPs and annexin V-binding MPs compared with RBCs stored in SAG-M. RBCs stored in erythrosol-4 had increased adherence to endothelium at days 42 and 49 compared with RBCs stored in SAG-M or PAGGSM. RBCs stored in PAGGSM or Erythrosol-4 had improved retention of RBC membrane and osmotic resilience. The development of new additive solutions may offer improved quality of RBC components prepared from WB held overnight at room temperature. © 2010 American Association of Blood Banks.

  7. Synchrotron-based FTIR microspectroscopy for the mapping of photo-oxidation and additives in acrylonitrile-butadiene-styrene model samples and historical objects.

    PubMed

    Saviello, Daniela; Pouyet, Emeline; Toniolo, Lucia; Cotte, Marine; Nevin, Austin

    2014-09-16

    Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-μFTIR) was used to map photo-oxidative degradation of acrylonitrile-butadiene-styrene (ABS) and to investigate the presence and the migration of additives in historical samples from important Italian design objects. High resolution (3×3 μm(2)) molecular maps were obtained by FTIR microspectroscopy in transmission mode, using a new method for the preparation of polymer thin sections. The depth of photo-oxidation in samples was evaluated and accompanied by the formation of ketones, aldehydes, esters, and unsaturated carbonyl compounds. This study demonstrates selective surface oxidation and a probable passivation of material against further degradation. In polymer fragments from design objects made of ABS from the 1960s, UV-stabilizers were detected and mapped, and microscopic inclusions of proteinaceous material were identified and mapped for the first time. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Optimizing Frozen Sample Preparation for Laser Microdissection: Assessment of CryoJane Tape-Transfer System®

    PubMed Central

    Golubeva, Yelena G.; Smith, Roberta M.; Sternberg, Lawrence R.

    2013-01-01

    Laser microdissection is an invaluable tool in medical research that facilitates collecting specific cell populations for molecular analysis. Diversity of research targets (e.g., cancerous and precancerous lesions in clinical and animal research, cell pellets, rodent embryos, etc.) and varied scientific objectives, however, present challenges toward establishing standard laser microdissection protocols. Sample preparation is crucial for quality RNA, DNA and protein retrieval, where it often determines the feasibility of a laser microdissection project. The majority of microdissection studies in clinical and animal model research are conducted on frozen tissues containing native nucleic acids, unmodified by fixation. However, the variable morphological quality of frozen sections from tissues containing fat, collagen or delicate cell structures can limit or prevent successful harvest of the desired cell population via laser dissection. The CryoJane Tape-Transfer System®, a commercial device that improves cryosectioning outcomes on glass slides has been reported superior for slide preparation and isolation of high quality osteocyte RNA (frozen bone) during laser dissection. Considering the reported advantages of CryoJane for laser dissection on glass slides, we asked whether the system could also work with the plastic membrane slides used by UV laser based microdissection instruments, as these are better suited for collection of larger target areas. In an attempt to optimize laser microdissection slide preparation for tissues of different RNA stability and cryosectioning difficulty, we evaluated the CryoJane system for use with both glass (laser capture microdissection) and membrane (laser cutting microdissection) slides. We have established a sample preparation protocol for glass and membrane slides including manual coating of membrane slides with CryoJane solutions, cryosectioning, slide staining and dissection procedure, lysis and RNA extraction that facilitated

  9. Determination of protein carbonyls in plasma, cell extracts, tissue homogenates, isolated proteins: Focus on sample preparation and derivatization conditions

    PubMed Central

    Weber, Daniela; Davies, Michael J.; Grune, Tilman

    2015-01-01

    Protein oxidation is involved in regulatory physiological events as well as in damage to tissues and is thought to play a key role in the pathophysiology of diseases and in the aging process. Protein-bound carbonyls represent a marker of global protein oxidation, as they are generated by multiple different reactive oxygen species in blood, tissues and cells. Sample preparation and stabilization are key steps in the accurate quantification of oxidation-related products and examination of physiological/pathological processes. This review therefore focuses on the sample preparation processes used in the most relevant methods to detect protein carbonyls after derivatization with 2,4-dinitrophenylhydrazine with an emphasis on measurement in plasma, cells, organ homogenates, isolated proteins and organelles. Sample preparation, derivatization conditions and protein handling are presented for the spectrophotometric and HPLC method as well as for immunoblotting and ELISA. An extensive overview covering these methods in previously published articles is given for researchers who plan to measure protein carbonyls in different samples. PMID:26141921

  10. Rep. Bill Nelson prepares to photograph samples of protein crystal growth

    NASA Image and Video Library

    1986-01-12

    61C-05-036 (12-18 Jan. 1986) --- U.S. Representative Bill Nelson (Democrat - Florida), STS-61C payload specialist, prepares to photograph individual samples in the Handheld Protein Crystal Growth Experiment (HPCG) on Columbia's middeck. The operations involve the use of four pieces of equipment to attempt the growth of 60 different types of crystals -- 12 by means of dialysis and 48 via the vapor diffusion method. The photo was used by members of the STS-61C crew at their Jan. 23, 1986, Post-Flight Press Conference.

  11. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  12. Surface Modified Particles By Multi-Step Addition And Process For The Preparation Thereof

    DOEpatents

    Cook, Ronald Lee; Elliott, Brian John; Luebben, Silvia DeVito; Myers, Andrew William; Smith, Bryan Matthew

    2006-01-17

    The present invention relates to a new class of surface modified particles and to a multi-step surface modification process for the preparation of the same. The multi-step surface functionalization process involves two or more reactions to produce particles that are compatible with various host systems and/or to provide the particles with particular chemical reactivities. The initial step comprises the attachment of a small organic compound to the surface of the inorganic particle. The subsequent steps attach additional compounds to the previously attached organic compounds through organic linking groups.

  13. Simultaneous derivatization/preconcentration of volatile aldehydes with a miniaturized fiber-packed sample preparation device designed for gas chromatographic analysis.

    PubMed

    Saito, Yoshihiro; Ueta, Ikuo; Ogawa, Mitsuhiro; Jinno, Kiyokatsu

    2006-10-01

    A novel in-needle sample preparation device has been developed for the determination of volatile aldehydes in gaseous samples. The needle device is designed for the gas chromatographic (GC) analysis of aldehydes and ketones commonly found in typical in-house environments. In order to prepare the extraction device, a bundle of polymer-coated filaments was longitudinally packed into a specially designed needle. Derivatization reactions were prompted by 2,4-dinitrophenylhydrazine (NDPH) included in the needle, and so the aldehydes and ketones were derivatized to the corresponding hydrazones and extracted with the extraction needle. A reproducible extraction needle preparation process was established, along with a repeatable derivatization/extraction process that ensures the successful determination of aldehydes. The storage performance of the extraction needle was also evaluated at room temperature for three days. The results demonstrate the successful application of the fiber-packed extraction device to the preparation of a gaseous sample of aldehydes, and the future possibility of applying the extraction device to the analysis of in-house environments.

  14. Glycan characterization of the NIST RM monoclonal antibody using a total analytical solution: From sample preparation to data analysis.

    PubMed

    Hilliard, Mark; Alley, William R; McManus, Ciara A; Yu, Ying Qing; Hallinan, Sinead; Gebler, John; Rudd, Pauline M

    Glycosylation is an important attribute of biopharmaceutical products to monitor from development through production. However, glycosylation analysis has traditionally been a time-consuming process with long sample preparation protocols and manual interpretation of the data. To address the challenges associated with glycan analysis, we developed a streamlined analytical solution that covers the entire process from sample preparation to data analysis. In this communication, we describe the complete analytical solution that begins with a simplified and fast N-linked glycan sample preparation protocol that can be completed in less than 1 hr. The sample preparation includes labelling with RapiFluor-MS tag to improve both fluorescence (FLR) and mass spectral (MS) sensitivities. Following HILIC-UPLC/FLR/MS analyses, the data are processed and a library search based on glucose units has been included to expedite the task of structural assignment. We then applied this total analytical solution to characterize the glycosylation of the NIST Reference Material mAb 8761. For this glycoprotein, we confidently identified 35 N-linked glycans and all three major classes, high mannose, complex, and hybrid, were present. The majority of the glycans were neutral and fucosylated; glycans featuring N-glycolylneuraminic acid and those with two galactoses connected via an α1,3-linkage were also identified.

  15. Sludge batch 9 (SB9) acceptance evaluation. Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bannochie, C. J.; Diprete, D. P.; Pareizs, J. M.

    Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a composition expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

  16. Sludge batch 9 (SB9) accepance evaluation: Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bannochie, C.; Diprete, D.; Pareizs, J.

    Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a compositioniv expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

  17. Advantages and Disadvantages of using a Focused Ion Beam to Prepare TEM Samples From Irradiated U-10Mo Monolithic Nuclear Fuel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    B. D. Miller; J. Gan; J. Madden

    2012-05-01

    Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and focused ion beam (FIB) milling were performed on an irradiated U-10Mo monolithic fuel to understand its irradiation microstructure. This is the first reported TEM work of irradiated fuel sample prepared using a FIB. Advantages and disadvantages of using the FIB to create TEM samples from this irradiated fuel will be presented along with some results from the work. Sample preparation techniques used to create SEM and FIB samples from the brittle irradiated monolithic sample will also be discussed.

  18. A simple and automated sample preparation system for subsequent halogens determination: Combustion followed by pyrohydrolysis.

    PubMed

    Pereira, L S F; Pedrotti, M F; Vecchia, P Dalla; Pereira, J S F; Flores, E M M

    2018-06-20

    A simple and automated system based on combustion followed by a pyrohydrolysis reaction was proposed for further halogens determination. This system was applied for digestion of soils containing high (90%) and also low (10%) organic matter content for further halogens determination. The following parameters were evaluated: sample mass, use of microcrystalline cellulose and heating time. For analytes absorption, a diluted alkaline solution (6 mL of 25 mmol L -1  NH 4 OH) was used in all experiments. Up to 400 mg of soil with high organic matter content and 100 mg of soil with low organic matter content (mixed with 400 mg of cellulose) could be completely digested using the proposed system. Quantitative results for all halogens were obtained using less than 12 min of sample preparation step (about 1.8 min for sample combustion and 10 min for pyrohydrolysis). The accuracy was evaluated using a certified reference material of coal and spiked samples. No statistical difference was observed between the certified values and results obtained by the proposed method. Additionally, the recoveries obtained using spiked samples were in the range of 98-103% with relative standard deviation values lower than 5%. The limits of quantification obtained for F, Cl, Br and I for soil with high (400 mg of soil) and low (100 mg of soil) organic matter were in the range of 0.01-2 μg g -1 and 0.07-59 μg g -1 , respectively. The proposed system was considered as a simple and suitable alternative for soils digestion for further halogens determination by ion chromatography and inductively coupled plasma mass spectrometry techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Multiresidue method for the determination of 77 pesticides in wine using QuEChERS sample preparation and gas chromatography with mass spectrometry.

    PubMed

    Jiang, Y; Li, X; Xu, J; Pan, C; Zhang, J; Niu, W

    2009-06-01

    A method based on a QuEChERS (quick, easy, cheap, effective, rugged, safe) sample preparation method and gas chromatography with mass spectrometric detection by selected ion monitoring (GC/MS-SIM) was developed for simultaneous determination of 77 pesticide residues in wine. An extraction of 10 ml of sample with acetonitrile followed by liquid-liquid partition formed by the addition of 4 g MgSO(4) and 3 g NaCl was applied in the sample preparation. The clean-up was carried out by applying dispersive solid-phase with 150 mg MgSO(4) as well as 50 mg primary secondary amine (PSA). One quantitation ion and at least two identification ions were selected in the analytical method for each pesticide compound by GC/MS. The recovery data were obtained by spiking blank samples at two concentration levels (0.05 and 0.2 mg l(-1)). The recoveries of all pesticides were in the range 70-110%, with intra-day precision of less than 15%, and the inter-day precision of less than 22% and 15% for 0.05 and 0.2 mg l(-1) fortification levels, respectively. Linearity was between 0.02 and 2 mg l(-1) with determination coefficients (R(2)) greater than 0.98 for all compounds. The limits of quantification (LOQs) for the 77 pesticides ranged from 0.003 to 0.05 mg l(-1). This method was applied for routine analysis in market products.

  20. The effects of sample preparation on measured concentrations of eight elements in edible tissues of fish from streams contaminated by lead mining

    USGS Publications Warehouse

    Schmitt, Christopher J.; Finger, Susan E.

    1987-01-01

    The influence of sample preparation on measured concentrations of eight elements in the edible tissues of two black basses (Centrarchidae), two catfishes (Ictaluridae), and the black redhorse,Moxostoma duquesnei (Catostomidae) from two rivers in southeastern Missouri contaminated by mining and related activities was investigated. Concentrations of Pb, Cd, Cu, Zn, Fe, Mn, Ba, and Ca were measured in two skinless, boneless samples of axial muscle from individual fish prepared in a clean room. One sample (normally-processed) was removed from each fish with a knife in a manner typically used by investigators to process fish for elemental analysis and presumedly representative of methods employed by anglers when preparing fish for home consumption. A second sample (clean-processed) was then prepared from each normally-processed sample by cutting away all surface material with acid-cleaned instruments under ultraclean conditions. The samples were analyzed as a single group by atomic absorption spectrophotometry. Of the elements studied, only Pb regularly exceeded current guidelines for elemental contaminants in foods. Concentrations were high in black redhorse from contaminated sites, regardless of preparation method; for the other fishes, whether or not Pb guidelines were exceeded depended on preparation technique. Except for Mn and Ca, concentrations of all elements measured were significantly lower in cleanthan in normally-processed tissue samples. Absolute differences in measured concentrations between clean- and normally-processed samples were most evident for Pb and Ba in bass and catfish and for Cd and Zn in redhorse. Regardless of preparation method, concentrations of Pb, Ca, Mn, and Ba in individual fish were closely correlated; samples that were high or low in one of these four elements were correspondingly high or low in the other three. In contrast, correlations between Zn, Fe, and Cd occurred only in normallyprocessed samples, suggesting that these

  1. 40 CFR 80.8 - Sampling methods for gasoline, diesel fuel, fuel additives, and renewable fuels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Sampling methods for gasoline, diesel... Provisions § 80.8 Sampling methods for gasoline, diesel fuel, fuel additives, and renewable fuels. The sampling methods specified in this section shall be used to collect samples of gasoline, diesel fuel...

  2. Determination of protein carbonyls in plasma, cell extracts, tissue homogenates, isolated proteins: Focus on sample preparation and derivatization conditions.

    PubMed

    Weber, Daniela; Davies, Michael J; Grune, Tilman

    2015-08-01

    Protein oxidation is involved in regulatory physiological events as well as in damage to tissues and is thought to play a key role in the pathophysiology of diseases and in the aging process. Protein-bound carbonyls represent a marker of global protein oxidation, as they are generated by multiple different reactive oxygen species in blood, tissues and cells. Sample preparation and stabilization are key steps in the accurate quantification of oxidation-related products and examination of physiological/pathological processes. This review therefore focuses on the sample preparation processes used in the most relevant methods to detect protein carbonyls after derivatization with 2,4-dinitrophenylhydrazine with an emphasis on measurement in plasma, cells, organ homogenates, isolated proteins and organelles. Sample preparation, derivatization conditions and protein handling are presented for the spectrophotometric and HPLC method as well as for immunoblotting and ELISA. An extensive overview covering these methods in previously published articles is given for researchers who plan to measure protein carbonyls in different samples. © 2015 Published by Elsevier Ltd.

  3. Antimicrobial 3D Porous Scaffolds Prepared by Additive Manufacturing and Breath Figures.

    PubMed

    Vargas-Alfredo, Nelson; Dorronsoro, Ane; Cortajarena, Aitziber L; Rodríguez-Hernández, Juan

    2017-10-25

    We describe herein a novel strategy for the fabrication of efficient 3D printed antibacterial scaffolds. For this purpose, both the surface topography as well as the chemical composition of 3D scaffolds fabricated by additive manufacturing were modified. The scaffolds were fabricated by fused deposition modeling (FDM) using high-impact polystyrene (HIPS) filaments. The surface of the objects was then topographically modified providing materials with porous surfaces by means of the Breath Figures approach. The strategy involves the immersion of the scaffold in a polymer solution during a precise period of time. This approach permitted the modification of the pore size varying the immersion time as well as the solution concentration. Moreover, by using polymer blend solutions of polystyrene and polystyrene-b-poly(acrylic acid) (PS 23 -b-PAA 18 ) and a quaternized polystyrene-b-poly(dimethylaminoethyl methacrylate) (PS 42 -b-PDMAEMAQ 17 ), the scaffolds were simultaneously chemically modified. The surfaces were characterized by scanning electron microscopy and infrared spectroscopy. Finally, the biological response toward bacteria was explored. Porous surfaces prepared using quaternized PDMAEMA as well as those prepared using PAA confer antimicrobial activity to the films, i.e., were able to kill on contact Staphylococcus aureus employed as model bacteria.

  4. Novel sample preparation method for surfactant containing suppositories: effect of micelle formation on drug recovery.

    PubMed

    Kalmár, Éva; Ueno, Konomi; Forgó, Péter; Szakonyi, Gerda; Dombi, György

    2013-09-01

    Rectal drug delivery is currently at the focus of attention. Surfactants promote drug release from the suppository bases and enhance the formulation properties. The aim of our work was to develop a sample preparation method for HPLC analysis for a suppository base containing 95% hard fat, 2.5% Tween 20 and 2.5% Tween 60. A conventional sample preparation method did not provide successful results as the recovery of the drug failed to fulfil the validation criterion 95-105%. This was caused by the non-ionic surfactants in the suppository base incorporating some of the drug, preventing its release. As guidance for the formulation from an analytical aspect, we suggest a well defined surfactant content based on the turbidimetric determination of the CMC (critical micelle formation concentration) in the applied methanol-water solvent. Our CMC data correlate well with the results of previous studies. As regards the sample preparation procedure, a study was performed of the effects of ionic strength and pH on the drug recovery with the avoidance of degradation of the drug during the procedure. Aminophenazone and paracetamol were used as model drugs. The optimum conditions for drug release from the molten suppository base were found to be 100 mM NaCl, 20-40 mM NaOH and a 30 min ultrasonic treatment of the final sample solution. As these conditions could cause the degradation of the drugs in the solution, this was followed by NMR spectroscopy, and the results indicated that degradation did not take place. The determined CMCs were 0.08 mM for Tween 20, 0.06 mM for Tween 60 and 0.04 mM for a combined Tween 20, Tween 60 system. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Total airborne mold particle sampling: evaluation of sample collection, preparation and counting procedures, and collection devices.

    PubMed

    Godish, Diana; Godish, Thad

    2008-02-01

    This study was conducted to evaluate (i) procedures used to collect, prepare, and count total airborne mold spore/particle concentrations, and (ii) the relative field performance of three commercially available total airborne mold spore/particle sampling devices. Differences between factory and laboratory airflow calibration values of axial fan-driven sampling instruments (used in the study) indicated a need for laboratory calibration using a mass flow meter to ensure that sample results were accurately calculated. An aniline blue-amended Calberla's solution adjusted to a pH of 4.2-4.4 provided good sample mounting/counting results using Dow Corning high vacuum grease, Dow Corning 280A adhesive, and Dow Corning 316 silicone release spray for samples collected using mini-Burkard and Allergenco samplers. Count variability among analysts was most pronounced in 5% counts of relatively low mold particle deposition density samples and trended downward with increased count percentage and particle deposition density. No significant differences were observed among means of 5, 10, and 20% counts and among analysts; a significant interaction effect was observed between analysts' counts and particle deposition densities. Significantly higher mini-Burkard and Air-O-Cell total mold spore/particle counts for 600x vs. 400x (1.9 and 2.3 x higher, respectively), 1000x vs. 600x (1.9 and 2.2 x higher, respectively) and 1000x vs. 400x (3.6 and 4.6 x higher, respectively) comparisons indicated that 1000x magnification counts best quantified total airborne mold spore/particles using light microscopy, and that lower magnification counts may result in unacceptable underreporting of airborne mold spore/particle concentrations. Modest but significantly higher (1.2x) total mold spore concentrations were observed with Allergenco vs. mini-Burkard samples collected in co-located, concurrently operated sampler studies; moderate but significantly higher mini-Burkard count values (1.4x) were

  6. Effect of sample preparation on the measurement of sugars, organic acids, and polyphenols in apple fruit by mid-infrared spectroscopy.

    PubMed

    Bureau, Sylvie; Scibisz, Iwona; Le Bourvellec, Carine; Renard, Catherine M G C

    2012-04-11

    The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition.

  7. A novel sample preparation method to avoid influence of embedding medium during nano-indentation

    Treesearch

    Yujie Meng; Siqun Wang; Zhiyong Cai; Timothy M. Young; Guanben Du; Yanjun Li

    2012-01-01

    The effect of the embedding medium on the nano-indentation measurements of lignocellulosic materials was investigated experimentally using nano-indentation. Both the reduced elastic modulus and the hardness of nonembedded cell walls were found to be lower than those of the embedded samples, proving that the embedding medium used for specimen preparation on cellulosic...

  8. Desulfurization of Cysteine-Containing Peptides Resulting from Sample Preparation for Protein Characterization by MS

    PubMed Central

    Wang, Zhouxi; Rejtar, Tomas; Zhou, Zhaohui Sunny; Karger, Barry L.

    2010-01-01

    In this paper, we have examined two cysteine modifications resulting from sample preparation for protein characterization by MS: (1) a previously observed conversion of cysteine to dehydroalanine, now found in the case of disulfide mapping and (2) a novel modification corresponding to conversion of cysteine to alanine. Using model peptides, the conversion of cysteine to dehydroalanine via β-elimination of a disulfide bond was seen to result from the conditions of typical tryptic digestion (37 °C, pH 7.0– 9.0) without disulfide reduction and alkylation.. Furthermore, the surprising conversion of cysteine to alanine was shown to occur by heating cysteine containing peptides in the presence of a phosphine (TCEP). The formation of alanine from cysteine, investigated by performing experiments in H2O or D2O, suggested a radical-based desulfurization mechanism unrelated to β-elimination. Importantly, an understanding of the mechanism and conditions favorable for cysteine desulfurization provides insight for the establishment of improved sample preparation procedures of protein analysis. PMID:20049891

  9. Capacitive deionization on-chip as a method for microfluidic sample preparation.

    PubMed

    Roelofs, Susan H; Kim, Bumjoo; Eijkel, Jan C T; Han, Jongyoon; van den Berg, Albert; Odijk, Mathieu

    2015-03-21

    Desalination as a sample preparation step is essential for noise reduction and reproducibility of mass spectrometry measurements. A specific example is the analysis of proteins for medical research and clinical applications. Salts and buffers that are present in samples need to be removed before analysis to improve the signal-to-noise ratio. Capacitive deionization is an electrostatic desalination (CDI) technique which uses two porous electrodes facing each other to remove ions from a solution. Upon the application of a potential of 0.5 V ions migrate to the electrodes and are stored in the electrical double layer. In this article we demonstrate CDI on a chip, and desalinate a solution by the removal of 23% of Na(+) and Cl(-) ions, while the concentration of a larger molecule (FITC-dextran) remains unchanged. For the first time impedance spectroscopy is introduced to monitor the salt concentration in situ in real-time in between the two desalination electrodes.

  10. CTEPP STANDARD OPERATING PROCEDURE FOR COLLECTION OF FOOD PREPARATION SURFACE WIPE SAMPLES FOR PERSISTENT ORGANIC POLLUTANTS (SOP-2.17)

    EPA Science Inventory

    This SOP describes the method for collection of the food preparation surface wipe samples for the measurement of persistent organic pollutants (POP). This method uses a wipe to collect POP residues from a surface where a study participant prepares food the most often (i.e., kitch...

  11. Miniaturized Sample Preparation and Rapid Detection of Arsenite in Contaminated Soil Using a Smartphone.

    PubMed

    Siddiqui, Mohd Farhan; Kim, Soocheol; Jeon, Hyoil; Kim, Taeho; Joo, Chulmin; Park, Seungkyung

    2018-03-04

    Conventional methods for analyzing heavy metal contamination in soil and water generally require laboratory equipped instruments, complex procedures, skilled personnel and a significant amount of time. With the advancement in computing and multitasking performances, smartphone-based sensors potentially allow the transition of the laboratory-based analytical processes to field applicable, simple methods. In the present work, we demonstrate the novel miniaturized setup for simultaneous sample preparation and smartphone-based optical sensing of arsenic As(III) in the contaminated soil. Colorimetric detection protocol utilizing aptamers, gold nanoparticles and NaCl have been optimized and tested on the PDMS-chip to obtain the high sensitivity with the limit of detection of 0.71 ppm (in the sample) and a correlation coefficient of 0.98. The performance of the device is further demonstrated through the comparative analysis of arsenic-spiked soil samples with standard laboratory method, and a good agreement with a correlation coefficient of 0.9917 and the average difference of 0.37 ppm, are experimentally achieved. With the android application on the device to run the experiment, the whole process from sample preparation to detection is completed within 3 hours without the necessity of skilled personnel. The approximate cost of setup is estimated around 1 USD, weight 55 g. Therefore, the presented method offers the simple, rapid, portable and cost-effective means for onsite sensing of arsenic in soil. Combined with the geometric information inside the smartphones, the system will allow the monitoring of the contamination status of soils in a nation-wide manner.

  12. Optimization of sample preparation variables for wedelolactone from Eclipta alba using Box-Behnken experimental design followed by HPLC identification.

    PubMed

    Patil, A A; Sachin, B S; Shinde, D B; Wakte, P S

    2013-07-01

    Coumestan wedelolactone is an important phytocomponent from Eclipta alba (L.) Hassk. It possesses diverse pharmacological activities, which have prompted the development of various extraction techniques and strategies for its better utilization. The aim of the present study is to develop and optimize supercritical carbon dioxide assisted sample preparation and HPLC identification of wedelolactone from E. alba (L.) Hassk. The response surface methodology was employed to study the optimization of sample preparation using supercritical carbon dioxide for wedelolactone from E. alba (L.) Hassk. The optimized sample preparation involves the investigation of quantitative effects of sample preparation parameters viz. operating pressure, temperature, modifier concentration and time on yield of wedelolactone using Box-Behnken design. The wedelolactone content was determined using validated HPLC methodology. The experimental data were fitted to second-order polynomial equation using multiple regression analysis and analyzed using the appropriate statistical method. By solving the regression equation and analyzing 3D plots, the optimum extraction conditions were found to be: extraction pressure, 25 MPa; temperature, 56 °C; modifier concentration, 9.44% and extraction time, 60 min. Optimum extraction conditions demonstrated wedelolactone yield of 15.37 ± 0.63 mg/100 g E. alba (L.) Hassk, which was in good agreement with the predicted values. Temperature and modifier concentration showed significant effect on the wedelolactone yield. The supercritical carbon dioxide extraction showed higher selectivity than the conventional Soxhlet assisted extraction method. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  13. Statistical inference for the additive hazards model under outcome-dependent sampling.

    PubMed

    Yu, Jichang; Liu, Yanyan; Sandler, Dale P; Zhou, Haibo

    2015-09-01

    Cost-effective study design and proper inference procedures for data from such designs are always of particular interests to study investigators. In this article, we propose a biased sampling scheme, an outcome-dependent sampling (ODS) design for survival data with right censoring under the additive hazards model. We develop a weighted pseudo-score estimator for the regression parameters for the proposed design and derive the asymptotic properties of the proposed estimator. We also provide some suggestions for using the proposed method by evaluating the relative efficiency of the proposed method against simple random sampling design and derive the optimal allocation of the subsamples for the proposed design. Simulation studies show that the proposed ODS design is more powerful than other existing designs and the proposed estimator is more efficient than other estimators. We apply our method to analyze a cancer study conducted at NIEHS, the Cancer Incidence and Mortality of Uranium Miners Study, to study the risk of radon exposure to cancer.

  14. Statistical inference for the additive hazards model under outcome-dependent sampling

    PubMed Central

    Yu, Jichang; Liu, Yanyan; Sandler, Dale P.; Zhou, Haibo

    2015-01-01

    Cost-effective study design and proper inference procedures for data from such designs are always of particular interests to study investigators. In this article, we propose a biased sampling scheme, an outcome-dependent sampling (ODS) design for survival data with right censoring under the additive hazards model. We develop a weighted pseudo-score estimator for the regression parameters for the proposed design and derive the asymptotic properties of the proposed estimator. We also provide some suggestions for using the proposed method by evaluating the relative efficiency of the proposed method against simple random sampling design and derive the optimal allocation of the subsamples for the proposed design. Simulation studies show that the proposed ODS design is more powerful than other existing designs and the proposed estimator is more efficient than other estimators. We apply our method to analyze a cancer study conducted at NIEHS, the Cancer Incidence and Mortality of Uranium Miners Study, to study the risk of radon exposure to cancer. PMID:26379363

  15. An improved FIB sample preparation technique for site-specific plan-view specimens: A new cutting geometry.

    PubMed

    Li, Chen; Habler, Gerlinde; Baldwin, Lisa C; Abart, Rainer

    2018-01-01

    Focused ion beam (FIB) sample preparation technique in plan-view geometry allows direct correlations of the atomic structure study via transmission electron microscopy with micrometer-scale property measurements. However, one main technical difficulty is that a large amount of material must be removed underneath the specimen. Furthermore, directly monitoring the milling process is difficult unless very large material volumes surrounding the TEM specimen site are removed. In this paper, a new cutting geometry is introduced for FIB lift-out sample preparation with plan-view geometry. Firstly, an "isolated" cuboid shaped specimen is cut out, leaving a "bridge" connecting it with the bulk material. Subsequently the two long sides of the "isolated" cuboid are wedged, forming a triangular prism shape. A micromanipulator needle is used for in-situ transfer of the specimen to a FIB TEM grid, which has been mounted parallel with the specimen surface using a simple custom-made sample slit. Finally, the grid is transferred to the standard FIB grid holder for final thinning with standard procedures. This new cutting geometry provides clear viewing angles for monitoring the milling process, which solves the difficulty of judging whether the specimen has been entirely detached from the bulk material, with the least possible damage to the surrounding materials. With an improved success rate and efficiency, this plan-view FIB lift-out specimen preparation technique should have a wide application for material science. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. FT-Raman and chemometric tools for rapid determination of quality parameters in milk powder: Classification of samples for the presence of lactose and fraud detection by addition of maltodextrin.

    PubMed

    Rodrigues Júnior, Paulo Henrique; de Sá Oliveira, Kamila; de Almeida, Carlos Eduardo Rocha; De Oliveira, Luiz Fernando Cappa; Stephani, Rodrigo; Pinto, Michele da Silva; de Carvalho, Antônio Fernandes; Perrone, Ítalo Tuler

    2016-04-01

    FT-Raman spectroscopy has been explored as a quick screening method to evaluate the presence of lactose and identify milk powder samples adulterated with maltodextrin (2.5-50% w/w). Raman measurements can easily differentiate samples of milk powder, without the need for sample preparation, while traditional quality control methods, including high performance liquid chromatography, are cumbersome and slow. FT-Raman spectra were obtained from samples of whole lactose and low-lactose milk powder, both without and with addition of maltodextrin. Differences were observed between the spectra involved in identifying samples with low lactose content, as well as adulterated samples. Exploratory data analysis using Raman spectroscopy and multivariate analysis was also developed to classify samples with PCA and PLS-DA. The PLS-DA models obtained allowed to correctly classify all samples. These results demonstrate the utility of FT-Raman spectroscopy in combination with chemometrics to infer about the quality of milk powder. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Additional of polyethylene glycol on the preparation of LaPO4:Eu3+ phosphor

    NASA Astrophysics Data System (ADS)

    Panatarani, Camellia; Joni, I. Made

    2013-09-01

    Solution phase method was used to synthesis nanocrystal LaPO4:Eu3+. Polyethylene glycol with vary molecular weight (MW) was added to allow an exothermic reaction to get a high crystalinity of LaPO4:Eu3+. The x-ray pattern of as prepared LaPO4 was obtained by using an X'pert PANalytical diffractometer with CuKα radiation (λ = 1.5406 Å) and the photoluminescent measurement spectra is obtained by using Fluorescence Spectrometer LS55, Perkin Elmer. The additional of various MW of polyethylene glycol into the precursor solution of LaPO4:Eu3+ affected the crystal structure and luminescent properties. Higher MW of PEG depressing the luminescent spectra. The emission origin from 5D0-7F4 transition vanished by additional 500,000 and 2,000,000 MW of PEG.

  18. Effort versus reward: preparing samples for fungal community characterization in high-throughput sequencing surveys of soils

    USDA-ARS?s Scientific Manuscript database

    Next generation fungal amplicon sequencing is being used with increasing frequency to study fungal diversity in various ecosystems; however, the influence of sample preparation on the characterization of fungal community is poorly understood. We investigated the effects of four procedural modificati...

  19. S-SIMS and MetA-SIMS study of organic additives in thin polymer coatings

    NASA Astrophysics Data System (ADS)

    Adriaensen, L.; Vangaever, F.; Lenaerts, J.; Gijbels, R.

    2006-07-01

    In the present study a methodology for TOF-S-SIMS measurements is developed to gain information on the distribution of molecules on and in polymer coatings (thickness ˜100 μm). Experiments were carried out on model systems consisting of one or more additive-containing polyvinylbutyral coatings. Several organic additives were selected: carbocyanine dyes, basonyl blue and the pharmaceutical risperidone. The additives have been measured as pure compounds on a Si substrate to obtain good reference spectra. After optimisation of the sample preparation method, the coatings were embedded in epoxy resin and stored in an oven (60 °C) for 24 h. Cross-sections were made by means of a microtome. S-SIMS spectra were taken on the prepared cross-sections before and after Au was deposited on the sample surface. Compared to the untreated samples, the Au covered samples give rise to more intense secondary ion signals. Generally, signals of the intact cations were more intense than those of the fragment ions. Apart from mass spectra, images of the additive distribution in the coatings could also be acquired by recording structural ion signals. It was possible to make secondary ion images of the additive molecule ions with a (sub)-micrometer lateral resolution.

  20. Sample preparation for radiocarbon ( 14C) measurements of carbonyl compounds in the atmosphere . quantifying the biogenic contribution

    NASA Astrophysics Data System (ADS)

    Larsen, B. R.; Brussol, C.; Kotzias, D.; Veltkamp, T.; Zwaagstra, O.; Slanina, J.

    A method has been developed for the preparation of samples for radiocarbon ( 14C) measurements of carbonyl compounds in the atmosphere. Sampling on 25 ml 2,4-dinitrophenylhydrazine (DNPH)- coated silica gel cartridges can be carried out with up to 10.000 ℓ of ambient air with no adverse effects on sample integrity. Methods for the selective clean-up of the extracts have been investigated. This is a necessary step in preparing ambient carbonyl samples for a measurement of the radiocarbon ( 14C) content. The method which gave the best results include extraction of the DNPH cartridge with CH 3CN and purification of the carbonyl hydrazones over activated silica gel to remove excess DNPH and non target compounds. This method has been validated with laboratory samples and has been proved to give reliable results The radiocarbon data from the first field experiment showed that ambient air over a semi-rural test site in Ispra, Italy on a late summer day contained mainly five carbonyls (formaldehyde>acetaldehyde>acetone>propanal>butanal) of a mixed biogenic (41-57%) and anthropogenic (43-59%) origin. The method will be used in future monitoring of radiocarbon ( 14C) on a number of test sites in Europe.

  1. New addition curing polyimides

    NASA Technical Reports Server (NTRS)

    Frimer, Aryeh A.; Cavano, Paul

    1991-01-01

    In an attempt to improve the thermal-oxidative stability (TOS) of PMR-type polymers, the use of 1,4-phenylenebis (phenylmaleic anhydride) PPMA, was evaluated. Two series of nadic end-capped addition curing polyimides were prepared by imidizing PPMA with either 4,4'-methylene dianiline or p-phenylenediamine. The first resulted in improved solubility and increased resin flow while the latter yielded a compression molded neat resin sample with a T(sub g) of 408 C, close to 70 C higher than PME-15. The performance of these materials in long term weight loss studies was below that of PMR-15, independent of post-cure conditions. These results can be rationalized in terms of the thermal lability of the pendant phenyl groups and the incomplete imidization of the sterically congested PPMA. The preparation of model compounds as well as future research directions are discussed.

  2. Quantification of Parvovirus B19 DNA Using COBAS AmpliPrep Automated Sample Preparation and LightCycler Real-Time PCR

    PubMed Central

    Schorling, Stefan; Schalasta, Gunnar; Enders, Gisela; Zauke, Michael

    2004-01-01

    The COBAS AmpliPrep instrument (Roche Diagnostics GmbH, D-68305 Mannheim, Germany) automates the entire sample preparation process of nucleic acid isolation from serum or plasma for polymerase chain reaction analysis. We report the analytical performance of the LightCycler Parvovirus B19 Quantification Kit (Roche Diagnostics) using nucleic acids isolated with the COBAS AmpliPrep instrument. Nucleic acids were extracted using the Total Nucleic Acid Isolation Kit (Roche Diagnostics) and amplified with the LightCycler Parvovirus B19 Quantification Kit. The kit combination processes 72 samples per 8-hour shift. The lower detection limit is 234 IU/ml at a 95% hit-rate, linear range approximately 104-1010 IU/ml, and overall precision 16 to 40%. Relative sensitivity and specificity in routine samples from pregnant women are 100% and 93%, respectively. Identification of a persistent parvovirus B19-infected individual by the polymerase chain reaction among 51 anti-parvovirus B19 IgM-negative samples underlines the importance of additional nucleic acid testing in pregnancy and its superiority to serology in identifying the risk of parvovirus B19 transmission via blood or blood products. Combination of the Total Nucleic Acid Isolation Kit on the COBAS AmpliPrep instrument with the LightCycler Parvovirus B19 Quantification Kit provides a reliable and time-saving tool for sensitive and accurate detection of parvovirus B19 DNA. PMID:14736825

  3. Studies of levels of biogenic amines in meat samples in relation to the content of additives.

    PubMed

    Jastrzębska, Aneta; Kowalska, Sylwia; Szłyk, Edward

    2016-01-01

    The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.

  4. Properties of zirconia-toughened-alumina prepared via powder processing and colloidal processing routes.

    PubMed

    Rafferty, A; Alsebaie, A M; Olabi, A G; Prescott, T

    2009-01-15

    Alumina-zirconia composites were prepared by two routes: powder processing, and colloidal processing. Unstabilised zirconia powder was added to alumina in 5 wt%, 10 wt% and 20 wt% quantities. For the colloidal method, zirconium(IV) propoxide solution was added to alumina powder, also in 5 wt%, 10 wt% and 20 wt% quantities. Additions of glacial acetic acid were needed to form stable suspensions. Suspension stability was verified by pH measurements and sedimentation testing. For the powder processed samples Vickers hardness decreased indefinitely with increasing ZrO(2) additions, but for colloidal samples the hardness at first decreased but then increased again above >10 wt% ZrO(2). Elastic modulus (E) values decreased with ZrO(2) additions. However, samples containing 20 wt% zirconia prepared via a colloidal method exhibited a much higher modulus than the powder processed equivalent. This was due to the homogeneous dispersion of zirconia yielding a sample which was less prone to microcracking.

  5. Preparation and Characterization of SN-38-Encapsulated Phytantriol Cubosomes Containing α-Monoglyceride Additives.

    PubMed

    Ali, Md Ashraf; Noguchi, Shuji; Iwao, Yasunori; Oka, Toshihiko; Itai, Shigeru

    2016-01-01

    SN-38 is a potent active metabolite of irinotecan that has been considered as an anticancer candidate. However, the clinical development of this compound has been hampered by its poor aqueous solubility and chemical instability. In this study, we developed SN-38-encapsulated cubosomes to resolve these problems. Six α-monoglyceride additives, comprising monocaprylin, monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin, were used to prepare phytantriol (PHYT) cubosomes by probe sonication. The mean particle size, polydispersity index, and zeta potential values of these systems were around 190-230 nm, 0.19-0.25 and -17 to -22 mV, respectively. Small-angle X-ray scattering analyses confirmed that the SN-38-encapsulated cubosomes existed in the Pn̄3m space group both with and without the additives. The monoglyceride additives led to around a two-fold increase in the solubility of SN-38 compared with the PHYT cubosome. The drug entrapment efficiency of PHYT cubosomes with additives was greater than 97%. The results of a stability study at 25°C showed no dramatic changes in the particle size or polydispersity index characteristics, with at least 85% of the SN-38 existing in its active lactone form after 10 d, demonstrating the high stability of the cubosome nanoparticles. Furthermore, approximately 55% of SN-38 was slowly released from the cubosomes with additives over 96 h in vitro under physiological conditions. Taken together, these results show that the SN-38-encapsulated PHYT cubosome particles are promising drug carriers that should be considered for further in vivo experiments, including drug delivery to tumor cells using the enhanced permeability and retention effect.

  6. Use of a holder-vacuum tube device to save on-site hands in preparing urine samples for head-space gas-chromatography, and its application to determine the time allowance for sample sealing.

    PubMed

    Kawai, Toshio; Sumino, Kimiaki; Ohashi, Fumiko; Ikeda, Masayuki

    2011-01-01

    To facilitate urine sample preparation prior to head-space gas-chromatographic (HS-GC) analysis. Urine samples containing one of the five solvents (acetone, methanol, methyl ethyl ketone, methyl isobutyl ketone and toluene) at the levels of biological exposure limits were aspirated into a vacuum tube via holder, a device commercially available for venous blood collection (the vacuum tube method). The urine sample, 5 ml, was quantitatively transferred to a 20-ml head-space vial prior to HS-GC analysis. The loaded tubes were stored at +4 ℃ in dark for up to 3 d. The vacuum tube method facilitated on-site procedures of urine sample preparation for HS-GC with no significant loss of solvents in the sample and no need of skilled hands, whereas on-site sample preparation time was significantly reduced. Furthermore, no loss of solvents was detected during the 3-d storage, irrespective of hydrophilic (acetone) or lipophilic solvent (toluene). In a pilot application, high performance of the vacuum tube method in sealing a sample in an air-tight space succeeded to confirm that no solvent will be lost when sealing is completed within 5 min after urine voiding, and that the allowance time is as long as 30 min in case of toluene in urine. The use of the holder-vacuum tube device not only saves hands for transfer of the sample to air-tight space, but facilitates sample storage prior to HS-GC analysis.

  7. Efficacy of screens in removing long fibers from an aerosol stream – sample preparation technique for toxicology studies

    PubMed Central

    Ku, Bon Ki; Deye, Gregory J.; Turkevich, Leonid A.

    2015-01-01

    Fiber dimension (especially length) and biopersistence are thought to be important variables in determining the pathogenicity of asbestos and other elongate mineral particles. In order to prepare samples of fibers for toxicology studies, it is necessary to develop and evaluate methods for separating fibers by length in the micrometer size range. In this study, we have filtered an aerosol of fibers through nylon screens to investigate whether such screens can efficiently remove the long fibers (L >20 μm, a typical macrophage size) from the aerosol stream. Such a sample, deficient in long fibers, could then be used as the control in a toxicology study to investigate the role of length. A well-dispersed aerosol of glass fibers (a surrogate for asbestos) was generated by vortex shaking a Japan Fibrous Material Research Association (JFMRA) glass fiber powder. Fibers were collected on a mixed cellulose ester (MCE) filter, imaged with phase contrast microscopy (PCM) and lengths were measured. Length distributions of the fibers that penetrated through various screens (10, 20 and 60 μm mesh sizes) were analyzed; additional study was made of fibers that penetrated through double screen and centrally blocked screen configurations. Single screens were not particularly efficient in removing the long fibers; however, the alternative configurations, especially the centrally blocked screen configuration, yielded samples substantially free of the long fibers. PMID:24417374

  8. Determination of ten pyrethroids in various fruit juices: comparison of dispersive liquid-liquid microextraction sample preparation and QuEChERS method combined with dispersive liquid-liquid microextraction.

    PubMed

    Zhang, Yaohai; Zhang, Xuelian; Jiao, Bining

    2014-09-15

    Dispersive liquid-liquid microextraction (DLLME) sample preparation and the quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with DLLME were developed and compared for the analysis of ten pyrethroids in various fruit juices using gas chromatography-electron capture detection (GC-ECD). QuEChERS-DLLME method has found its widespread applications to all the fruit juices including those samples with more complex matrices (orange, lemon, kiwi and mango) while DLLME was confined to the fruit juices with simpler matrices (apple, pear, grape and peach). The two methods provided acceptable recoveries and repeatability. In addition, the applicabilities of two methods were demonstrated with the real samples and further confirmed by gas chromatography-mass spectrometry (GC-MS). Copyright © 2014. Published by Elsevier Ltd.

  9. A comparison of sample preparation methods for extracting volatile organic compounds (VOCs) from equine faeces using HS-SPME.

    PubMed

    Hough, Rachael; Archer, Debra; Probert, Christopher

    2018-01-01

    Disturbance to the hindgut microbiota can be detrimental to equine health. Metabolomics provides a robust approach to studying the functional aspect of hindgut microorganisms. Sample preparation is an important step towards achieving optimal results in the later stages of analysis. The preparation of samples is unique depending on the technique employed and the sample matrix to be analysed. Gas chromatography mass spectrometry (GCMS) is one of the most widely used platforms for the study of metabolomics and until now an optimised method has not been developed for equine faeces. To compare a sample preparation method for extracting volatile organic compounds (VOCs) from equine faeces. Volatile organic compounds were determined by headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GCMS). Factors investigated were the mass of equine faeces, type of SPME fibre coating, vial volume and storage conditions. The resultant method was unique to those developed for other species. Aliquots of 1000 or 2000 mg in 10 ml or 20 ml SPME headspace were optimal. From those tested, the extraction of VOCs should ideally be performed using a divinylbenzene-carboxen-polydimethysiloxane (DVB-CAR-PDMS) SPME fibre. Storage of faeces for up to 12 months at - 80 °C shared a greater percentage of VOCs with a fresh sample than the equivalent stored at - 20 °C. An optimised method for extracting VOCs from equine faeces using HS-SPME-GCMS has been developed and will act as a standard to enable comparisons between studies. This work has also highlighted storage conditions as an important factor to consider in experimental design for faecal metabolomics studies.

  10. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DRINKING WATER SAMPLES FOR ANALYSIS OF PERSISTENT ORGANIC POLLUTANTS (SOP 5.23)

    EPA Science Inventory

    The method for extracting and preparing a drinking water sample for analysis of atrazine is summarized in this SOP. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/ mass spectrometry.

  11. Anopheles sinensis mosquito insecticide resistance: comparison of three mosquito sample collection and preparation methods and mosquito age in resistance measurements.

    PubMed

    Xu, Tielong; Zhong, Daibin; Tang, Linhua; Chang, Xuelian; Fu, Fengyang; Yan, Guiyun; Zheng, Bin

    2014-01-28

    Insecticide resistance monitoring in malaria mosquitoes is essential for guiding the rational use of insecticides in vector control programs. Resistance bioassay is the first step for insecticide monitoring and it lays an important foundation for molecular examination of resistance mechanisms. In the literature, various mosquito sample collection and preparation methods have been used, but how mosquito sample collection and preparation methods affect insecticide susceptibility bioassay results is largely unknown. The objectives of this study were to determine whether mosquito sample collection and preparation methods affected bioassay results, which may cause incorrect classification of mosquito resistance status. The study was conducted in Anopheles sinensis mosquitoes in two study sites in central China. Three mosquito sample collection and preparation methods were compared for insecticide susceptibility, kdr frequencies and metabolic enzyme activities: 1) adult mosquitoes collected from the field; 2) F1 adults from field collected, blood-fed mosquitoes; and 3) adult mosquitoes reared from field collected larvae. Mosquito sample collection and preparation methods significantly affected mortality rates in the standard WHO tube resistance bioassay. Mortality rate of field-collected female adults was 10-15% higher than in mosquitoes reared from field-collected larvae and F1 adults from field collected blood-fed females. This pattern was consistent in mosquitoes from the two study sites. High kdr mutation frequency (85-95%) with L1014F allele as the predominant mutation was found in our study populations. Field-collected female adults consistently exhibited the highest monooxygenase and GST activities. The higher mortality rate observed in the field-collected female mosquitoes may have been caused by a mixture of mosquitoes of different ages, as older mosquitoes were more susceptible to deltamethrin than younger mosquitoes. Female adults reared from field

  12. Sources of variability in collection and preparation of paint and lead-coating samples.

    PubMed

    Harper, S L; Gutknecht, W F

    2001-06-01

    Chronic exposure of children to lead (Pb) can result in permanent physiological impairment. Since surfaces coated with lead-containing paints and varnishes are potential sources of exposure, it is extremely important that reliable methods for sampling and analysis be available. The sources of variability in the collection and preparation of samples were investigated to improve the performance and comparability of methods and to ensure that data generated will be adequate for its intended use. Paint samples of varying sizes (areas and masses) were collected at different locations across a variety of surfaces including metal, plaster, concrete, and wood. A variety of grinding techniques were compared. Manual mortar and pestle grinding for at least 1.5 min and mechanized grinding techniques were found to generate similar homogenous particle size distributions required for aliquots as small as 0.10 g. When 342 samples were evaluated for sample weight loss during mortar and pestle grinding, 4% had 20% or greater loss with a high of 41%. Homogenization and sub-sampling steps were found to be the principal sources of variability related to the size of the sample collected. Analysis of samples from different locations on apparently identical surfaces were found to vary by more than a factor of two both in Pb concentration (mg cm-2 or %) and areal coating density (g cm-2). Analyses of substrates were performed to determine the Pb remaining after coating removal. Levels as high as 1% Pb were found in some substrate samples, corresponding to more than 35 mg cm-2 Pb. In conclusion, these sources of variability must be considered in development and/or application of any sampling and analysis methodologies.

  13. Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

    PubMed

    Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

    2016-06-01

    A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.

  14. A portable cryo-plunger for on-site intact cryogenic microscopy sample preparation in natural environments.

    PubMed

    Comolli, Luis R; Duarte, Robert; Baum, Dennis; Luef, Birgit; Downing, Kenneth H; Larson, David M; Csencsits, Roseann; Banfield, Jillian F

    2012-06-01

    We present a modern, light portable device specifically designed for environmental samples for cryogenic transmission-electron microscopy (cryo-TEM) by on-site cryo-plunging. The power of cryo-TEM comes from preparation of artifact-free samples. However, in many studies, the samples must be collected at remote field locations, and the time involved in transporting samples back to the laboratory for cryogenic preservation can lead to severe degradation artifacts. Thus, going back to the basics, we developed a simple mechanical device that is light and easy to transport on foot yet effective. With the system design presented here we are able to obtain cryo-samples of microbes and microbial communities not possible to culture, in their near-intact environmental conditions as well as in routine laboratory work, and in real time. This methodology thus enables us to bring the power of cryo-TEM to microbial ecology. Copyright © 2011 Wiley Periodicals, Inc.

  15. Simple and Fast Sample Preparation Followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) for the Analysis of 2- and 4-Methylimidazole in Cola and Dark Beer.

    PubMed

    Choi, Sol Ji; Jung, Mun Yhung

    2017-04-01

    We have developed a simple and fast sample preparation technique in combination with a gas chromatography-tandem mass spectrometry (GC-MS/MS) for the quantification of 2-methylimidazole (2-MeI) and 4-methylimidazole (4-MeI) in colas and dark beers. Conventional sample preparation technique for GC-MS requires laborious and time-consuming steps consisting of sample concentration, pH adjustment, ion pair extraction, centrifugation, back-extraction, centrifugation, derivatization, and extraction. Our sample preparation technique consists of only 2 steps (in situ derivation and extraction) which requires less than 3 min. This method provided high linearity, low limit of detection and limit of quantification, high recovery, and high intra- and interday repeatability. It was found that internal standard method with diluted stable isotope (4-MeI-d 6 ) and 2-ethylimidazole (2-EI) could not correctly compensate the matrix effects. Thus, standard addition technique was used for the quantification of 2- and 4-MeI. The established method was successfully applied to colas and dark beers for the determination of 2-MeI and 4-MeI. The 4-MeI contents in colas and dark beers ranged from 8 to 319 μg/L and from trace to 417 μg/L, respectively. Small quantity (0 to 8 μg/L) of 2-MeI was found only in dark beers. The contents of 4-MeI (22 μg/L) in colas obtained from fast food restaurants were significantly lower than those (177 μg/L) in canned or bottled colas. © 2017 Institute of Food Technologists®.

  16. 40 CFR 270.140 - What else must the Director prepare in addition to the draft RAP or notice of intent to deny?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false What else must the Director prepare in... the Director prepare in addition to the draft RAP or notice of intent to deny? Once the Director has... Regional office or published material that is generally available need not be physically included with the...

  17. Polyphosphoester-Camptothecin Prodrug with Reduction-Response Prepared via Michael Addition Polymerization and Click Reaction.

    PubMed

    Du, Xueqiong; Sun, Yue; Zhang, Mingzu; He, Jinlin; Ni, Peihong

    2017-04-26

    Polyphosphoesters (PPEs), as potential candidates for biocompatible and biodegradable polymers, play an important role in material science. Various synthetic methods have been employed in the preparation of PPEs such as polycondensation, polyaddition, ring-opening polymerization, and olefin metathesis polymerization. In this study, a series of linear PPEs has been prepared via one-step Michael addition polymerization. Subsequently, camptothecin (CPT) derivatives containing disulfide bonds and azido groups were linked onto the side chain of the PPE through Cu(I)-catalyzed azidealkyne cyclo-addition "click" chemistry to yield a reduction-responsive polymeric prodrug P(EAEP-PPA)-g-ss-CPT. The chemical structures were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared, ultraviolet-visible spectrophotometer, and high performance liquid chromatograph analyses, respectively. The amphiphilic prodrug could self-assemble into micelles in aqueous solution. The average particle size and morphology of the prodrug micelles were measured by dynamic light scattering and transmission electron microscopy, respectively. The results of size change under different conditions indicate that the micelles possess a favorable stability in physiological conditions and can be degraded in reductive medium. Moreover, the studies of in vitro drug release behavior confirm the reduction-responsive degradation of the prodrug micelles. A methyl thiazolyl tetrazolium assay verifies the good biocompatibility of P(EAEP-PPA) not only for normal cells, but also for tumor cells. The results of cytotoxicity and the intracellular uptake about prodrug micelles further demonstrate that the prodrug micelles can efficiently release CPT into 4T1 or HepG2 cells to inhibit the cell proliferation. All these results show that the polyphosphoester-based prodrug can be used for triggered drug delivery system in cancer treatment.

  18. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Fletcher, James C. (Inventor); Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1992-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  19. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1993-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of the additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  20. Preparation and multi-properties determination of radium-containing rocklike material

    NASA Astrophysics Data System (ADS)

    Hong, Changshou; Li, Xiangyang; Zhao, Guoyan; Jiang, Fuliang; Li, Ming; Zhang, Shuai; Wang, Hong; Liu, Kaixuan

    2018-02-01

    The radium-containing rocklike material were fabricated using distilled water, ordinary Portland cement and additives mixed aggregates and admixtures according to certain proportion. The physico-mechanical properties as well as radioactive properties of the prepared rocklike material were measured. Moreover, the properties of typical granite sample were also investigated. It is found on one hand, similarities exist in physical and mechanical properties between the rocklike material and the granite sample, this confirms the validity of the proposed method; on the other hand, the rocklike material generally performs more remarkable radioactive properties compared with the granite sample, while radon diffusive properties in both materials are essentially matching. This study will provide a novel way to prepare reliable radium-containing samples for radon study of underground uranium mine.

  1. Detection of cytomegalovirus (CMV) DNA in EDTA whole-blood samples: evaluation of the quantitative artus CMV LightCycler PCR kit in conjunction with automated sample preparation.

    PubMed

    Michelin, Birgit D A; Hadzisejdic, Ita; Bozic, Michael; Grahovac, Maja; Hess, Markus; Grahovac, Blazenka; Marth, Egon; Kessler, Harald H

    2008-04-01

    Whole blood has been found to be a reliable matrix for the detection and quantitation of cytomegalovirus (CMV) DNA. In this study, the performance of the artus CMV LightCycler (LC) PCR kit in conjunction with automated sample preparation on a BioRobot EZ1 workstation was evaluated. The accuracy, linearity, analytical sensitivity, and inter- and intra-assay variations were determined. A total of 102 clinical EDTA whole-blood samples were investigated, and results were compared with those obtained with the in vitro diagnostics (IVD)/Conformité Européene (CE)-labeled CMV HHV6,7,8 R-gene quantification kit. When the accuracy of the new kit was tested, seven of eight results were found to be within +/-0.5 log(10) unit of the expected panel results. Determination of linearity resulted in a quasilinear curve over more than 5 log units. The lower limit of detection of the assay was determined to be 139 copies/ml in EDTA whole blood. The interassay variation ranged from 15 to 58%, and the intra-assay variation ranged from 7 to 35%. When clinical samples were tested and the results were compared with those of the routinely used IVD/CE-labeled assay, 53 samples tested positive and 13 samples tested negative by both of the assays. One sample was found to be positive with the artus CMV LC PCR kit only, and 35 samples tested positive with the routinely used assay only. The majority of discrepant results were found with low-titer samples. In conclusion, use of the artus CMV LC PCR kit in conjunction with automated sample preparation on the BioRobot EZ1 workstation may be suitable for the detection and quantitation of CMV DNA in EDTA whole blood in the routine low-throughput laboratory; however, low-positive results may be missed by this assay.

  2. Advantages of infrared transflection micro spectroscopy and paraffin-embedded sample preparation for biological studies

    NASA Astrophysics Data System (ADS)

    Yao, Jie; Li, Qian; Zhou, Bo; Wang, Dan; Wu, Rie

    2018-04-01

    Fourier-Transform Infrared micro-spectroscopy is an excellent method for biological analyses. In this paper, series metal coating films on ITO glass were prepared by the electrochemical method and the different thicknesses of paraffin embedding rat's brain tissue on the substrates were studied by IR micro-spetroscopy in attenuated total reflection (ATR) mode and transflection mode respectively. The Co-Ni-Cu alloy coating film with low cost is good reflection substrates for the IR analysis. The infrared microscopic transflection mode needs not to touch the sample at all and can get the IR spectra with higher signal to noise ratios. The Paraffin-embedding method allows tissues to be stored for a long time for re-analysis to ensure the traceability of the sample. Also it isolates the sample from the metal and avoids the interaction of biological tissue with the metals. The best thickness of the tissues is 4 μm.

  3. How Confocal Is Confocal Raman Microspectroscopy on the Skin? Impact of Microscope Configuration and Sample Preparation on Penetration Depth Profiles.

    PubMed

    Lunter, Dominique Jasmin

    2016-01-01

    The aim of the study was to elucidate the effect of sample preparation and microscope configuration on the results of confocal Raman microspectroscopic evaluation of the penetration of a pharmaceutical active into the skin (depth profiling). Pig ear skin and a hydrophilic formulation containing procaine HCl were used as a model system. The formulation was either left on the skin during the measurement, or was wiped off or washed off prior to the analysis. The microscope configuration was varied with respect to objectives and pinholes used. Sample preparation and microscope configuration had a tremendous effect on the results of depth profiling. Regarding sample preparation, the best results could be observed when the formulation was washed off the skin prior to the analysis. Concerning microscope configuration, the use of a 40 × 0.6 numerical aperture (NA) objective in combination with a 25-µm pinhole or a 100 × 1.25 NA objective in combination with a 50-µm pinhole was found to be advantageous. Complete removal of the sample from the skin before the analysis was found to be crucial. A thorough analysis of the suitability of the chosen microscope configuration should be performed before acquiring concentration depth profiles. © 2016 S. Karger AG, Basel.

  4. Microwave Processing for Sample Preparation to Evaluate Mitochondrial Ultrastructural Damage in Hemorrhagic Shock

    NASA Astrophysics Data System (ADS)

    Josephsen, Gary D.; Josephsen, Kelly A.; Beilman, Greg J.; Taylor, Jodie H.; Muiler, Kristine E.

    2005-12-01

    This is a report of the adaptation of microwave processing in the preparation of liver biopsies for transmission electron microscopy (TEM) to examine ultrastructural damage of mitochondria in the setting of metabolic stress. Hemorrhagic shock was induced in pigs via 35% total blood volume bleed and a 90-min period of shock followed by resuscitation. Hepatic biopsies were collected before shock and after resuscitation. Following collection, biopsies were processed for TEM by a rapid method involving microwave irradiation (Giberson, 2001). Samples pre- and postshock of each of two animals were viewed and scored using the mitochondrial ultrastructure scoring system (Crouser et al., 2002), a system used to quantify the severity of ultrastructural damage during shock. Results showed evidence of increased ultrastructural damage in the postshock samples, which scored 4.00 and 3.42, versus their preshock controls, which scored 1.18 and 1.27. The results of this analysis were similar to those obtained in another model of shock (Crouser et al., 2002). However, the amount of time used to process the samples was significantly shortened with methods involving microwave irradiation.

  5. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING SOLID FOOD SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.28)

    EPA Science Inventory

    This SOP describes the extraction and preparation of a solid food sample for analysis of acidic persistent organic pollutants such as acid herbicides, pentachlorphenol, and 3,5,6-trichloro-2-phenol. It covers the extraction, concentration and derivatization of samples that are to...

  6. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING LIQUID FOOD SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.29)

    EPA Science Inventory

    This SOP describes the extraction and preparation of a liquid food sample for analysis of acidic persistent organic pollutants such as acid herbicides, pentachlorphenol, and 3,5,6-trichloro-2-phenol. It covers the extraction, concentration and derivatization of samples that are t...

  7. Practical aspects of the use of the X(2) holder for HRTEM-quality TEM sample preparation by FIB.

    PubMed

    van Mierlo, Willem; Geiger, Dorin; Robins, Alan; Stumpf, Matthias; Ray, Mary Louise; Fischione, Paul; Kaiser, Ute

    2014-12-01

    The X(2) holder enables the effective production of thin, electron transparent samples for high-resolution transmission electron microscopy (HRTEM). Improvements to the X(2) holder for high-quality transmission electron microscopy (TEM) sample preparation are presented in this paper. We discuss the influence of backscattered electrons (BSE) from the sample holder in determining the lamella thickness in situ and demonstrate that a significant improvement in thickness determination can be achieved by comparatively simple means using the relative BSE intensity. We show (using Monte Carlo simulations) that by taking into account the finite collection angle of the electron backscatter detector, an approximately 20% underestimation of the lamella thickness in a silicon sample can be avoided. However, a correct thickness determination for light-element lamellas still remains a problem with the backscatter method; we introduce a more accurate method using the energy dispersive X-ray spectroscopy (EDX) signal for in situ thickness determination. Finally, we demonstrate how to produce a thin lamella with a nearly damage-free surface using the X(2) holder in combination with sub-kV polishing in the Fischione Instruments׳ NanoMill(®) TEM specimen preparation system. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Fully Automated Sample Preparation for Ultrafast N-Glycosylation Analysis of Antibody Therapeutics.

    PubMed

    Szigeti, Marton; Lew, Clarence; Roby, Keith; Guttman, Andras

    2016-04-01

    There is a growing demand in the biopharmaceutical industry for high-throughput, large-scale N-glycosylation profiling of therapeutic antibodies in all phases of product development, but especially during clone selection when hundreds of samples should be analyzed in a short period of time to assure their glycosylation-based biological activity. Our group has recently developed a magnetic bead-based protocol for N-glycosylation analysis of glycoproteins to alleviate the hard-to-automate centrifugation and vacuum-centrifugation steps of the currently used protocols. Glycan release, fluorophore labeling, and cleanup were all optimized, resulting in a <4 h magnetic bead-based process with excellent yield and good repeatability. This article demonstrates the next level of this work by automating all steps of the optimized magnetic bead-based protocol from endoglycosidase digestion, through fluorophore labeling and cleanup with high-throughput sample processing in 96-well plate format, using an automated laboratory workstation. Capillary electrophoresis analysis of the fluorophore-labeled glycans was also optimized for rapid (<3 min) separation to accommodate the high-throughput processing of the automated sample preparation workflow. Ultrafast N-glycosylation analyses of several commercially relevant antibody therapeutics are also shown and compared to their biosimilar counterparts, addressing the biological significance of the differences. © 2015 Society for Laboratory Automation and Screening.

  9. Preparation of isolated biomolecules for SFM observations: T4 bacteriophage as a test sample.

    PubMed Central

    Droz, E; Taborelli, M; Wells, T N; Descouts, P

    1993-01-01

    The T4 bacteriophage has been used to investigate protocols for the preparation of samples for scanning force microscopy in air, in order to obtaining reproducible images. The resolution of images and the distribution of bacteriophages on the substrate depends on the buffer type, its concentration, the surface treatment of substrate, and the method of deposition. The best imaging conditions for the phages require dilution in a volatile buffer at low ionic strength and adsorption onto hydrophilic surfaces. When imaging with the scanning force microscopy the quality of the images is influenced by the vertical and lateral forces applied on the sample and by the tip geometry. Images FIGURE 1 FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 6 PMID:8241398

  10. Offline solid phase microextraction sampling system

    DOEpatents

    Harvey, Chris A.

    2008-12-16

    An offline solid phase microextraction (SPME) sampling apparatus for enabling SPME samples to be taken a number of times from a previously collected fluid sample (e.g. sample atmosphere) stored in a fused silica lined bottle which keeps volatile organics in the fluid sample stable for weeks at a time. The offline SPME sampling apparatus has a hollow body surrounding a sampling chamber, with multiple ports through which a portion of a previously collected fluid sample may be (a) released into the sampling chamber, (b) SPME sampled to collect analytes for subsequent GC analysis, and (c) flushed/purged using a fluidically connected vacuum source and purging fluid source to prepare the sampling chamber for additional SPME samplings of the same original fluid sample, such as may have been collected in situ from a headspace.

  11. Preparation of Solid Derivatives by Differential Scanning Calorimetry.

    ERIC Educational Resources Information Center

    Crandall, E. W.; Pennington, Maxine

    1980-01-01

    Describes the preparation of selected aldehydes and ketones, alcohols, amines, phenols, haloalkanes, and tertiaryamines by differential scanning calorimetry. Technique is advantageous because formation of the reaction product occurs and the melting point of the product is obtained on the same sample in a short time with no additional purification…

  12. Determination of total phthalate in cosmetics using a simple three-phase sample preparation method.

    PubMed

    Liu, Laping; Wang, Zhengmeng; Zhao, Sihan; Duan, Jiahui; Tao, Hu; Wang, Wenji; Liu, Shuhui

    2018-02-01

    A simple sample preparation method requiring minimal organic solvents is proposed for the determination of the total phthalate content in cosmetics by high-performance liquid chromatography-tandem mass spectrometry. The hydrolysis of phthalates and purification of interfering substances were performed in a three-phase system that included an upper n-hexane phase, a middle ethanol phase, and a lower aqueous alkali solution. This three-phase system utilized an incremental purification strategy. The apolar ingredients were extracted with n-hexane, the polar pigments accumulated in the ethanol phase, and the hydrolysis product, phthalic acid, remained in the hydrolysate. Under the optimized conditions, the correlation coefficients (r) for the calibration curves were 0.998-0.999 in the range 0.60-12 mol L -1 . The limit of detection was 5.1 μmol kg -1 , and the limit of quantification was 9.2 μmol kg -1 . The recoveries varied from 84 to 97% with RSDs equal to or lower than 11%. The intra-day and inter-day repeatability values, expressed as the relative standard deviation, were less than 8.7 and 9.8, respectively. No obvious matrix effect existed in the different cosmetics matrices. The validated method was applied for the analysis of 57 commercial cosmetic samples. Graphical abstract Analysis of phthalates in cosmetics using a three-phase preparation method.

  13. Preparation of 'near' homogeneous samples for the analysis of matrix-assisted laser desorption/ionisation processes

    NASA Astrophysics Data System (ADS)

    Allwood, D. A.; Perera, I. K.; Perkins, J.; Dyer, P. E.; Oldershaw, G. A.

    1996-11-01

    Highly uniform thin films of samples for matrix-assisted laser desorption/ionisation (MALDI) have been fabricated by depositing a saturated solution of ferulic acid onto a soda lime glass disc and crushing with polished aluminium, the films covering large areas of the substrate and having a thickness between 45-60 μm. The effects that different substrates and crushing materials as well as sample concentration and sample recrystallisation have on these films has been examined by scanning electron microscopy. Such films have been shown to have a lower threshold fluence for matrix ion detection than standard dried-droplet samples, the reduction being approximately 15% for three of the five matrices analysed. An explanation for this is proposed in terms of crushed samples possessing a greater average energy per unit volume coupled to them by the laser due to their improved surface uniformity. Furthermore, samples that are dried at refrigerated temperatures (˜ 2.25°C) are shown to have a much improved macroscopic uniformity over samples dried at room temperature. Refrigerated and crushed MALDI samples yield analyte ions with good spot-to-spot and pulse-to-pulse reproducibility and both preparation steps appear to improve the resolution of spectra obtained with a time-of-flight mass spectrometer.

  14. Cytological preparations for molecular analysis: A review of technical procedures, advantages and limitations for referring samples for testing.

    PubMed

    da Cunha Santos, G; Saieg, M A; Troncone, G; Zeppa, P

    2018-04-01

    Minimally invasive procedures such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) must yield not only good quality and quantity of material for morphological assessment, but also an adequate sample for analysis of molecular markers to guide patients to appropriate targeted therapies. In this context, cytopathologists worldwide should be familiar with minimum requirements for refereeing cytological samples for testing. The present manuscript is a review with comprehensive description of the content of the workshop entitled Cytological preparations for molecular analysis: pre-analytical issues for EBUS TBNA, presented at the 40th European Congress of Cytopathology in Liverpool, UK. The present review emphasises the advantages and limitations of different types of cytology substrates used for molecular analysis such as archival smears, liquid-based preparations, archival cytospin preparations and FTA (Flinders Technology Associates) cards, as well as their technical requirements/features. These various types of cytological specimens can be successfully used for an extensive array of molecular studies, but the quality and quantity of extracted nucleic acids rely directly on adequate pre-analytical assessment of those samples. In this setting, cytopathologists must not only be familiar with the different types of specimens and associated technical procedures, but also correctly handle the material provided by minimally invasive procedures, ensuring that there is sufficient amount of material for a precise diagnosis and correct management of the patient through personalised care. © 2018 John Wiley & Sons Ltd.

  15. Matrix-assisted laser desorption/ionization sample preparation optimization for structural characterization of poly(styrene-co-pentafluorostyrene) copolymers.

    PubMed

    Tisdale, Evgenia; Kennedy, Devin; Xu, Xiaodong; Wilkins, Charles

    2014-01-15

    The influence of the sample preparation parameters (the choice of the matrix, matrix:analyte ratio, salt:analyte ratio) was investigated and optimal conditions were established for the MALDI time-of-flight mass spectrometry analysis of the poly(styrene-co-pentafluorostyrene) copolymers. These were synthesized by atom transfer radical polymerization. Use of 2,5-dihydroxybenzoic acid as matrix resulted in spectra with consistently high ion yields for all matrix:analyte:salt ratios tested. The optimized MALDI procedure was successfully applied to the characterization of three copolymers obtained by varying the conditions of polymerization reaction. It was possible to establish the nature of the end groups, calculate molecular weight distributions, and determine the individual length distributions for styrene and pentafluorostyrene monomers, contained in the resulting copolymers. Based on the data obtained, it was concluded that individual styrene chain length distributions are more sensitive to the change in the composition of the catalyst (the addition of small amount of CuBr2) than is the pentafluorostyrene component distribution. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Preparation and purification of organic samples for selenium isotope studies.

    PubMed

    Banning, Helena; Stelling, Monika; König, Stephan; Schoenberg, Ronny; Neumann, Thomas

    2018-01-01

    Selenium (Se) is an important micronutrient but also a strong toxin with a narrow tolerance range for many organisms. As such, a globally heterogeneous Se distribution in soils is responsible for various disease patterns (i.e. Se excess and deficiency) and environmental problems, whereby plants play a key role for the Se entrance into the biosphere. Selenium isotope variations were proved to be a powerful tracer for redox processes and are therefore promising for the exploration of the species dependent Se metabolism in plants and the Se cycling within the Critical Zone. Plant cultivation setups enable systematic controlled investigations, but samples derived from them-plant tissue and phytoagar-are particularly challenging and require specific preparation and purification steps to ensure precise and valid Se isotope analytics performed with HG-MC-ICP-MS. In this study, different methods for the entire process from solid tissue preparation to Se isotope measurements were tested, optimized and validated. A particular microwave digestion procedure for plant tissue and a vacuum filtration method for phytoagar led to full Se recoveries, whereby unfavorable organic residues were reduced to a minimum. Three purification methods predominantly described in the literature were systematically tested with pure Se solution, high concentrated multi-element standard solution as well as plant and phytoagar as target matrices. All these methods efficiently remove critical matrix elements, but differ in Se recovery and organic residues. Validation tests doping Se-free plant material and phytoagar with a reference material of known Se isotope composition revealed the high impact of organic residues on the accuracy of MC-ICP-MS measurements. Only the purification method with no detectable organic residues, hydride generation and trapping, results in valid mass bias correction for plant samples with an average deviation to true δ82/76Se values of 0.2 ‰ and a reproducibility (2 SD

  17. Preparation and purification of organic samples for selenium isotope studies

    PubMed Central

    Stelling, Monika; König, Stephan; Schoenberg, Ronny; Neumann, Thomas

    2018-01-01

    Selenium (Se) is an important micronutrient but also a strong toxin with a narrow tolerance range for many organisms. As such, a globally heterogeneous Se distribution in soils is responsible for various disease patterns (i.e. Se excess and deficiency) and environmental problems, whereby plants play a key role for the Se entrance into the biosphere. Selenium isotope variations were proved to be a powerful tracer for redox processes and are therefore promising for the exploration of the species dependent Se metabolism in plants and the Se cycling within the Critical Zone. Plant cultivation setups enable systematic controlled investigations, but samples derived from them–plant tissue and phytoagar–are particularly challenging and require specific preparation and purification steps to ensure precise and valid Se isotope analytics performed with HG-MC-ICP-MS. In this study, different methods for the entire process from solid tissue preparation to Se isotope measurements were tested, optimized and validated. A particular microwave digestion procedure for plant tissue and a vacuum filtration method for phytoagar led to full Se recoveries, whereby unfavorable organic residues were reduced to a minimum. Three purification methods predominantly described in the literature were systematically tested with pure Se solution, high concentrated multi-element standard solution as well as plant and phytoagar as target matrices. All these methods efficiently remove critical matrix elements, but differ in Se recovery and organic residues. Validation tests doping Se-free plant material and phytoagar with a reference material of known Se isotope composition revealed the high impact of organic residues on the accuracy of MC-ICP-MS measurements. Only the purification method with no detectable organic residues, hydride generation and trapping, results in valid mass bias correction for plant samples with an average deviation to true δ82/76Se values of 0.2 ‰ and a reproducibility (2

  18. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DERMAL WIPE SAMPLES FOR ANALYSIS OF NEUTRAL PERSISTENT ORGANIC POLLUTANTS (SOP-5.16)

    EPA Science Inventory

    The method for extracting and preparing a dermal (hand) wipe sample for analysis of neutral persistent organic pollutants is summarized in this SOP. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mass spectrometry.

  19. Lights Will Guide You : Sample Preparation and Applications for Integrated Laser and Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Karreman, M. A.

    2013-03-01

    Correlative microscopy is the combined use of two different forms of microscopy in the study of a specimen, allowing for the exploitation of the advantages of both imaging tools. The integrated Laser and Electron Microscope (iLEM), developed at Utrecht University, combines a fluorescence microscope (FM) and a transmission electron microscope (TEM) in a single set-up. The region of interest in the specimen is labeled or tagged with a fluorescent probe and can easily be identified within a large field of view with the FM. Next, this same area is retraced in the TEM and can be studied at high resolution. The iLEM demands samples that can be imaged with both FM and TEM. Biological specimen, typically composed of light elements, generate low image contrast in the TEM. Therefore, these samples are often ‘contrasted’ with heavy metal stains. FM, on the other hand, images fluorescent samples. Sample preparation for correlative microscopy, and iLEM in particular, is complicated by the fact that the heavy metals stains employed for TEM quench the fluorescent signal of the probe that is imaged with FM. The first part of this thesis outlines preparation procedures for biological material yielding specimen that can be imaged with the iLEM. Here, approaches for the contrasting of thin sections of cells and tissue are introduced that do not affect the fluorescence signal of the probe that marks the region of interest. Furthermore, two novel procedures, VIS2FIXH and VIS2FIX­FS are described that allow for the chemical fixation of thin sections of cryo-immobilized material. These procedures greatly expedite the sample preparation process, and open up novel possibilities for the immuno-labeling of difficult antigens, eg. proteins and lipids that are challenging to preserve. The second part of this thesis describes applications of iLEM in research in the field of life and material science. The iLEM was employed in the study of UVC induced apoptosis (programmed cell death) of

  20. Solid Phase Microextraction and Related Techniques for Drugs in Biological Samples

    PubMed Central

    Moein, Mohammad Mahdi; Said, Rana; Bassyouni, Fatma

    2014-01-01

    In drug discovery and development, the quantification of drugs in biological samples is an important task for the determination of the physiological performance of the investigated drugs. After sampling, the next step in the analytical process is sample preparation. Because of the low concentration levels of drug in plasma and the variety of the metabolites, the selected extraction technique should be virtually exhaustive. Recent developments of sample handling techniques are directed, from one side, toward automatization and online coupling of sample preparation units. The primary objective of this review is to present the recent developments in microextraction sample preparation methods for analysis of drugs in biological fluids. Microextraction techniques allow for less consumption of solvent, reagents, and packing materials, and small sample volumes can be used. In this review the use of solid phase microextraction (SPME), microextraction in packed sorbent (MEPS), and stir-bar sorbtive extraction (SBSE) in drug analysis will be discussed. In addition, the use of new sorbents such as monoliths and molecularly imprinted polymers will be presented. PMID:24688797

  1. Study of sample preparation for quantitative analysis of amino acids in human sweat by liquid chromatography-tandem mass spectrometry.

    PubMed

    Delgado-Povedano, M M; Calderón-Santiago, M; Priego-Capote, F; Luque de Castro, M D

    2016-01-01

    The determination of physiological levels of amino acids is important to aid in the diagnosis and treatment of several diseases and nutritional status of individuals. Amino acids are frequently determined in biofluids such as blood (serum or plasma) and urine; however, there are less common biofluids with different concentration profiles of amino acids that could be of interest. One of these biofluids is sweat that can be obtained in a non-invasive manner and is characterized by low complex composition. The analysis of amino acids in human sweat requires the development of sample preparation strategies according to the sample matrix and small collected volume. The influence of sample preparation on the quantitative analysis of amino acids in sweat by LC-MS/MS has been assessed through a comparison between two strategies: dilution of sweat and centrifugal microsolid-phase extraction (c-μSPE). In both cases, several dilution factors were assayed for in-depth knowledge of the matrix effects, and the use of c-μSPE provided the best results in terms of accuracy. The behavior of the target analytes was a function of the dilution factor, thus providing a pattern for sample preparation that depended on the amino acid to be determined. The concentration of amino acids in sweat ranges between 6.20 ng mL(-1) (for homocysteine) and 259.77 µg mL(-1) (for serine) with precision, expressed as relative standard deviation, within 1.1-21.4%. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS

    PubMed Central

    Schaepe, Kaija; Kokesch-Himmelreich, Julia; Rohnke, Marcus; Wagner, Alena-Svenja; Schaaf, Thimo; Wenisch, Sabine; Janek, Jürgen

    2015-01-01

    In ToF-SIMS analysis, the experimental outcome from cell experiments is to a great extent influenced by the sample preparation routine. In order to better judge this critical influence in the case of lipid analysis, a detailed comparison of different sample preparation routines is performed—aiming at an optimized preparation routine for systematic lipid imaging of cell cultures. For this purpose, human mesenchymal stem cells were analyzed: (a) as chemically fixed, (b) freeze-dried, and (c) frozen-hydrated. For chemical fixation, different fixatives, i.e., glutaraldehyde, paraformaldehyde, and a mixture of both, were tested with different postfixative handling procedures like storage in phosphate buffered saline, water or critical point drying. Furthermore, secondary lipid fixation via osmium tetroxide was taken into account and the effect of an ascending alcohol series with and without this secondary lipid fixation was evaluated. Concerning freeze-drying, three different postprocessing possibilities were examined. One can be considered as a pure cryofixation technique while the other two routes were based on chemical fixation. Cryofixation methods known from literature, i.e., freeze-fracturing and simple frozen-hydrated preparation, were also evaluated to complete the comparison of sample preparation techniques. Subsequent data evaluation of SIMS spectra in both, positive and negative, ion mode was performed via principal component analysis by use of peak sets representative for lipids. For freeze-fracturing, these experiments revealed poor reproducibility making this preparation route unsuitable for systematic investigations and statistic data evaluation. Freeze-drying after cryofixation showed improved reproducibility and well preserved lipid contents while the other freeze-drying procedures showed drawbacks in one of these criteria. In comparison, chemical fixation techniques via glutar- and/or paraformaldehyde proved most suitable in terms of reproducibility

  3. Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS.

    PubMed

    Schaepe, Kaija; Kokesch-Himmelreich, Julia; Rohnke, Marcus; Wagner, Alena-Svenja; Schaaf, Thimo; Wenisch, Sabine; Janek, Jürgen

    2015-03-19

    In ToF-SIMS analysis, the experimental outcome from cell experiments is to a great extent influenced by the sample preparation routine. In order to better judge this critical influence in the case of lipid analysis, a detailed comparison of different sample preparation routines is performed-aiming at an optimized preparation routine for systematic lipid imaging of cell cultures. For this purpose, human mesenchymal stem cells were analyzed: (a) as chemically fixed, (b) freeze-dried, and (c) frozen-hydrated. For chemical fixation, different fixatives, i.e., glutaraldehyde, paraformaldehyde, and a mixture of both, were tested with different postfixative handling procedures like storage in phosphate buffered saline, water or critical point drying. Furthermore, secondary lipid fixation via osmium tetroxide was taken into account and the effect of an ascending alcohol series with and without this secondary lipid fixation was evaluated. Concerning freeze-drying, three different postprocessing possibilities were examined. One can be considered as a pure cryofixation technique while the other two routes were based on chemical fixation. Cryofixation methods known from literature, i.e., freeze-fracturing and simple frozen-hydrated preparation, were also evaluated to complete the comparison of sample preparation techniques. Subsequent data evaluation of SIMS spectra in both, positive and negative, ion mode was performed via principal component analysis by use of peak sets representative for lipids. For freeze-fracturing, these experiments revealed poor reproducibility making this preparation route unsuitable for systematic investigations and statistic data evaluation. Freeze-drying after cryofixation showed improved reproducibility and well preserved lipid contents while the other freeze-drying procedures showed drawbacks in one of these criteria. In comparison, chemical fixation techniques via glutar- and/or paraformaldehyde proved most suitable in terms of reproducibility

  4. Preparation and application of a tyre-based activated carbon solid phase extraction of heavy metals in wastewater samples

    NASA Astrophysics Data System (ADS)

    Dimpe, K. Mogolodi; Ngila, J. C.; Nomngongo, Philiswa N.

    2018-06-01

    In this paper, the tyre-based activated carbon solid phase extraction (SPE) method was successfully developed for simultaneous preconcentration of metal ions in the model and real water samples before their determination using flame atomic absorption spectrometry (FAAS). The activation of carbon was achieved by chemical activation and the tyre-based activated carbon was used as a sorbent for solid phase extraction. The prepared activated carbon was characterized using the scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and Fourier Transform Infrared spectroscopy. Moreover, optimization of the proposed method was performed by the two-level full factorial design (FFD). The FFD was chosen in order to fully investigate the effect of the experimental variables (pH, eluent concentration and sample flow rate) that significantly influence the preconcentration procedure. In this model, individual factors are considered along with their interactions. In addition, modelling of the experiments allowed simultaneous variation of all experimental factors investigated, reduced the required time and number of experimental runs which consequently led to the reduction of the overall required costs. Under optimized conditions, the limits of detection and quantification (LOD and LOQ) ranged 0.66-2.12 μg L-1and 1.78-5.34 μg L-1, respectively and the enrichment factor of 25 was obtained. The developed SPE/FAAS method was validated using CWW-TM-A and CWW-TM-B wastewater standard reference materials (SRMs). The procedure showed to be accurate with satisfactory recoveries ranging from 92 to 99%. The precision (repeatability) was lower than 4% in terms of the relative standard deviation (%RSD). The developed method proved to have the capability to be used in routine analysis of heavy metals in domestic and industrial wastewater samples. In addition, the developed method can be used as a final step (before being discharged to the rivers) in wastewater treatment process in

  5. Low-Cost 3D Printers Enable High-Quality and Automated Sample Preparation and Molecular Detection

    PubMed Central

    Chan, Kamfai; Coen, Mauricio; Hardick, Justin; Gaydos, Charlotte A.; Wong, Kah-Yat; Smith, Clayton; Wilson, Scott A.; Vayugundla, Siva Praneeth; Wong, Season

    2016-01-01

    Most molecular diagnostic assays require upfront sample preparation steps to isolate the target’s nucleic acids, followed by its amplification and detection using various nucleic acid amplification techniques. Because molecular diagnostic methods are generally rather difficult to perform manually without highly trained users, automated and integrated systems are highly desirable but too costly for use at point-of-care or low-resource settings. Here, we showcase the development of a low-cost and rapid nucleic acid isolation and amplification platform by modifying entry-level 3D printers that cost between $400 and $750. Our modifications consisted of replacing the extruder with a tip-comb attachment that houses magnets to conduct magnetic particle-based nucleic acid extraction. We then programmed the 3D printer to conduct motions that can perform high-quality extraction protocols. Up to 12 samples can be processed simultaneously in under 13 minutes and the efficiency of nucleic acid isolation matches well against gold-standard spin-column-based extraction technology. Additionally, we used the 3D printer’s heated bed to supply heat to perform water bath-based polymerase chain reactions (PCRs). Using another attachment to hold PCR tubes, the 3D printer was programmed to automate the process of shuttling PCR tubes between water baths. By eliminating the temperature ramping needed in most commercial thermal cyclers, the run time of a 35-cycle PCR protocol was shortened by 33%. This article demonstrates that for applications in resource-limited settings, expensive nucleic acid extraction devices and thermal cyclers that are used in many central laboratories can be potentially replaced by a device modified from inexpensive entry-level 3D printers. PMID:27362424

  6. Thermal Decomposition Behaviors and Burning Characteristics of Composite Propellants Prepared Using Combined Ammonium Perchlorate/Ammonium Nitrate Particles

    NASA Astrophysics Data System (ADS)

    Kohga, Makoto; Handa, Saori

    2018-01-01

    The thermal decomposition behaviors and burning characteristics of propellants prepared with combined ammonium perchlorate (AP)/ammonium nitrate (AN) particles greatly depended on the AN content (χ) of the AP/AN sample. The thermal decomposition behaviors of the propellants prepared with the combined samples almost matched those of the propellants prepared by physically mixing AP and AN particles, while their burning characteristics differed. The use of combined AP/AN particles decreased the heterogeneity of the combustion waves of the AP/AN propellants because of the difference in the combustion wave structure. In contrast, the addition of Fe2O3 caused unsteady combustion of the propellants prepared using samples with χ values lower than 8.1%.

  7. Sample Preparation and Extraction in Small Sample Volumes Suitable for Pediatric Clinical Studies: Challenges, Advances, and Experiences of a Bioanalytical HPLC-MS/MS Method Validation Using Enalapril and Enalaprilat

    PubMed Central

    Burckhardt, Bjoern B.; Laeer, Stephanie

    2015-01-01

    In USA and Europe, medicines agencies force the development of child-appropriate medications and intend to increase the availability of information on the pediatric use. This asks for bioanalytical methods which are able to deal with small sample volumes as the trial-related blood lost is very restricted in children. Broadly used HPLC-MS/MS, being able to cope with small volumes, is susceptible to matrix effects. The latter restrains the precise drug quantification through, for example, causing signal suppression. Sophisticated sample preparation and purification utilizing solid-phase extraction was applied to reduce and control matrix effects. A scale-up from vacuum manifold to positive pressure manifold was conducted to meet the demands of high-throughput within a clinical setting. Faced challenges, advances, and experiences in solid-phase extraction are exemplarily presented on the basis of the bioanalytical method development and validation of low-volume samples (50 μL serum). Enalapril, enalaprilat, and benazepril served as sample drugs. The applied sample preparation and extraction successfully reduced the absolute and relative matrix effect to comply with international guidelines. Recoveries ranged from 77 to 104% for enalapril and from 93 to 118% for enalaprilat. The bioanalytical method comprising sample extraction by solid-phase extraction was fully validated according to FDA and EMA bioanalytical guidelines and was used in a Phase I study in 24 volunteers. PMID:25873972

  8. RNA sample preparation applied to gene expression profiling for the horse biological passport.

    PubMed

    Bailly-Chouriberry, Ludovic; Baudoin, Florent; Cormant, Florence; Glavieux, Yohan; Loup, Benoit; Garcia, Patrice; Popot, Marie-Agnès; Bonnaire, Yves

    2017-09-01

    The improvement of doping control is an ongoing race. Techniques to fight doping are usually based on the direct detection of drugs or their metabolites by analytical methods such as chromatography hyphenated to mass spectrometry after ad hoc sample preparation. Nowadays, omic methods constitute an attractive development and advances have been achieved particularly by application of molecular biology tools for detection of anabolic androgenic steroids (AAS), erythropoiesis-stimulating agent (ESA), or to control human growth hormone misuses. These interesting results across different animal species have suggested that modification of gene expression offers promising new methods of improving the window of detection of banned substances by targeting their effects on blood cell gene expression. In this context, the present study describes the possibility of using a modified version of the dedicated Human IVD (in vitro Diagnostics) PAXgene® Blood RNA Kit for horse gene expression analysis in blood collected on PAXgene® tubes applied to the horse biological passport. The commercial kit was only approved for human blood samples and has required an optimization of specific technical requirements for equine blood samples. Improvements and recommendations were achieved for sample collection, storage and RNA extraction procedure. Following these developments, RNA yield and quality were demonstrated to be suitable for downstream gene expression analysis by qPCR techniques. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Effects of Graphene Oxide Addition on Mechanical and Thermal Properties of Evoh Films

    NASA Astrophysics Data System (ADS)

    González-Ruiz, Jesús; Yataco-Lazaro, Lourde; Virginio, Sueli; das Graças da Silva-Valenzuela, Maria; Moura, Esperidiana; Valenzuela-Díaz, Francisco

    Currently, ethylene vinyl alcohol (EVOH) is one of the oxygen barrier materials most used for food packaging. The addition of graphene oxide nanosheets to the EVOH matrix is employed to improve their mechanic al and barrier properties. In this work, films of EVOH-based composites reinforced with graphene oxide were prepared by melt extrusion, using a twin screw extruder machine and blown extrusion process. The graphene oxide was prepared via chemical oxidation of natural graphite and then was exfoliated into nanosheets using the sonochemical method. The composite films samples were characterized using FTIR and DSC analysis. In addition, their mechanical properties were also determined.

  10. Toxicity bioassays with concentrated cell culture media-a methodology to overcome the chemical loss by conventional preparation of water samples.

    PubMed

    Niss, Frida; Rosenmai, Anna Kjerstine; Mandava, Geeta; Örn, Stefan; Oskarsson, Agneta; Lundqvist, Johan

    2018-04-01

    The use of in vitro bioassays for studies of toxic activity in environmental water samples is a rapidly expanding field of research. Cell-based bioassays can assess the total toxicity exerted by a water sample, regardless whether the toxicity is caused by a known or unknown agent or by a complex mixture of different agents. When using bioassays for environmental water samples, it is often necessary to concentrate the water samples before applying the sample. Commonly, water samples are concentrated 10-50 times. However, there is always a risk of losing compounds in the sample in such sample preparation. We have developed an alternative experimental design by preparing a concentrated cell culture medium which was then diluted in the environmental water sample to compose the final cell culture media for the in vitro assays. Water samples from five Swedish waste water treatment plants were analyzed for oxidative stress response, estrogen receptor (ER), and aryl hydrocarbon receptor (AhR) activity using this experimental design. We were able to detect responses equivalent to 8.8-11.3 ng/L TCCD for AhR activity and 0.4-0.9 ng/L 17β-estradiol for ER activity. We were unable to detect oxidative stress response in any of the studied water samples. In conclusion, we have developed an experimental design allowing us to examine environmental water samples in toxicity in vitro assays at a concentration factor close to 1, without the risk of losing known or unknown compounds during an extraction procedure.

  11. Addition of Lubiprostone to polyethylene glycol(PEG) enhances the quality & efficacy of colonoscopy preparation: a randomized, double-blind, placebo controlled trial.

    PubMed

    Banerjee, Rupa; Chaudhari, Hrushikesh; Shah, Nirish; Saravanan, Arjunan; Tandan, Manu; Reddy, D Nageshwar

    2016-10-13

    Adequate bowel preparation is an essential prerequisite for complete mucosal visualization during colonoscopy. Polyethylene glycol (PEG) solutions are commonly used. However the large volume of the solution is often poorly tolerated. Addition of Lubiprostone (LB) could improve the adequacy of standard PEG preparation & reduce requirement. The aims to assess adequacy of PEG preparation with addition of single dose LB (24mcg) vs placebo and efficacy of reduced dose PEG + LB compared with full dose PEG + LB. Single center prospective double blind randomized controlled trial. Part I: 442 patients for colonoscopy randomized to receive placebo (GrA) or single dose of LB (GrB) prior to PEG preparation. Quality of bowel preparation graded 0-9 according to Boston Bowel Preparation Scale (BBPS). BBPS-9: excellent and BBPS 0-4: repeat procedure. Part II: 146 patients randomized to receive LB + 1.5 L PEG (GrC; 75) or LB + 1 L PEG (GrD; 71). BBPS score compared with GrB (2 L PEG). Part I: 442 patients (221 GrA & 221 Gr B). LB resulted in significant improvement in total BBPS (7.44 + 0.14 vs. 6.36 + 0.16, p < 0.0001). 66.5 % Gr B vs 38 % Gr A had excellent prep; 42.5 % GrB vs 24 % GrA had adequate prep. Repeat procedure needed 9.5 % Gr B vs 16.7 % Gr A (P < 0.01). Part II: No difference in BBPS scores with lower doses (Gr C&D) compared to standard (GrB) (Mean BBPS 7.44 + 0.14 GrA,7.30 + 0.25 GrC;7.25 + 0.26 GrD;p >0.05). Single dose LB prior to PEG significantly enhanced bowel preparation compared to PEG alone. There was no significant difference in quality of preparation with lower doses of PEG when combined with LB. The study protocol was approved by institutional review board and the trial was registered on March 22, 2011 with clinicaltrials.gov ( NCT01324284 ).

  12. Workshop on Mars 2001: Integrated Science in Preparation for Sample Return and Human Exploration

    NASA Technical Reports Server (NTRS)

    Marshall, John (Editor); Weitz, Cathy (Editor)

    1999-01-01

    The Workshop on Mars 2001: Integrated Science in Preparation for Sample Return and Human Exploration was held on October 2-4, 1999, at the Lunar and Planetary Institute in Houston, Texas. The workshop was sponsored by the Lunar and Planetary Institute, the Mars Program Office of the Jet Propulsion Laboratory, and the National Aeronautics and Space Administration. The three-day meeting was attended by 133 scientists whose purpose was to share results from recent missions, to share plans for the 2001 mission, and to come to an agreement on a landing site for this mission.

  13. preparation of microgram samples on iron wool for radiocarbon analysis via accelerator mass spectrometry: A closed-system approach

    NASA Astrophysics Data System (ADS)

    Verkouteren, R. Michael; Klouda, George A.; Currie, Lloyd A.; Donahue, Douglas J.; Jull, A. J. Timothy; Linick, T. W.

    1987-11-01

    A technique has been developed at NBS for the production of high quality targets for radiocarbon analysis by accelerator mass spectrometry (AMS). Our process optimizes chemical yields, ion currents and characterizes the chemical blank. The approach encompasses sample combustion to CO 2, catalytic reduction of CO 2 by Zn to CO, reduction to graphitic carbon on high-purity iron wool and in situ formation of a homogeneous iron-carbon bead; all steps are performed in a closed system. The total measurement system blank and variability are considered in the light of contributions from combustion, iron wool, reduction, bead formation and instrument blank. Additionally, use of this approach provides an increase in throughput, i.e. the effective management of large numbers of samples. Chemical yields for 50-800 μg C samples deposited on 15 mg iron wool were greater than 90%. Integrated 12C - ion currents observed were significant, being 4-64% of those observed in pure graphite. These currents are about an order of magnitude greater than those expected from dilution of graphite with an inert substrate. Isotopic accuracy, precision and blank were assessed by measuring the {14C }/{13C } ratios of a series of targets prepared from dead carbon and oxalic acid (SRM 4990C). Each target was typically measured for one hour; bead consumption was estimated at 5% to 10%. System blank subsequent to combustion was equivalent to (2.2 ± 0.5) μg modern carbon (chemistry + instrument); combustion blank currently stands at (0.4 ± 0.1) (SE, n = 6) μg C.

  14. An International Marine-Atmospheric 222Rn Measurement Intercomparison in Bermuda Part I: NIST Calibration and Methodology for Standardized Sample Additions

    PubMed Central

    Collé, R.; Unterweger, M. P.; Hodge, P. A.; Hutchinson, J. M. R.

    1996-01-01

    As part of an international 222Rn measurement intercomparison conducted at Bermuda in October 1991, NIST provided standardized sample additions of known, but undisclosed (“blind”) 222Rn concentrations that could be related to U.S. national standards. The standardized sample additions were obtained with a calibrated 226Ra source and a specially-designed manifold used to obtain well-known dilution factors from simultaneous flow-rate measurements. The additions were introduced over sampling periods of several hours (typically 4 h) into a common streamline on a sampling tower used by the participating laboratories for their measurements. The standardized 222Rn activity concentrations for the intercomparison ranged from approximately 2.5 Bq · m−3 to 35 Bq · m−3 (of which the lower end of this range approached concentration levels for ambient Bermudian air) and had overall uncertainties, approximating a 3 standard deviation uncertainty interval, of about 6 % to 13 %. This paper describes the calibration and methodology for the standardized sample additions. PMID:27805090

  15. Effect of sample preparation procedure for the determination of As, Sb and Se in fruit juices by HG-ICP-OES.

    PubMed

    Welna, Maja; Szymczycha-Madeja, Anna

    2014-09-15

    Various sample preparation procedures for the simultaneous determination of As, Sb and Se in fruit juices by hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP-OES) were examined. Applicability of total wet digestion with HNO3/H2O2, partial decomposition (solubilisation in aqua regia), 1:1 dilution with 2% (v/v) HNO3 and direct analysis were evaluated. Hydrides were generated in the reaction of an acidified sample with NaBH4 after pre-reduction with KI-ascorbic acid for total As and Sb, and boiling with HCl for total Se. Best results, i.e. limits of detection (LODs) of 0.51-0.73 ng mL(-1), precision (RSD) within 1.7-3.6% and recoveries for spiked samples between 101% and 106% were found using aqua regia treatment. This procedure simplifying and improving sample preparation step prior to As, Sb and Se measurements in fruit juices by HG-ICP-OES, thus could be adequate for the routine analysis in terms of the quality control of these drinks. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Effects of dietary fiber preparations made from maize starch on the growth and activity of selected bacteria from the Firmicutes, Bacteroidetes, and Actinobacteria phyla in fecal samples from obese children.

    PubMed

    Barczynska, Renata; Slizewska, Katarzyna; Litwin, Mieczyslaw; Szalecki, Mieczyslaw; Kapusniak, Janusz

    2016-01-01

    Currently, there is a search for substances that would be very well tolerated by an organism and which could contribute to the activation of the growth of Bacteroidetes and Actinobacteria strains, with simultaneous inhibition of the growth of Firmicutes. High expectations in this regard are raised with the use of fiber preparations from starch - resistant corn dextrins, branched dextrins, resistant maltodextrins and soluble corn fiber. In this paper, the influence of fiber preparations made from corn starch was evaluated on growth and activity of Bacteroidetes, Actinobacteria and Firmicutes strains isolated from obese children. It was demonstrated that in the stool of obese children Firmicutes strains predominate, while Bacteroidetes and Actinobacteria strains were in the minority. A supplementation of fecal culture with fiber preparations did not cause any significant changes in the number of strains of Bacteroidetes and Firmicutes. Addition of fiber preparations to the fecal samples of obese children increased the amount of short-chain fatty acids, especially acetic (p < 0.01), propionic, butyric (p = 0.05) and lactic acid (p < 0.01).

  17. Micro-structural characterization of precipitation-synthesized fluorapatite nano-material by transmission electron microscopy using different sample preparation techniques.

    PubMed

    Chinthaka Silva, G W; Ma, Longzhou; Hemmers, Oliver; Lindle, Dennis

    2008-01-01

    Fluorapatite is a naturally occurring mineral of the apatite group and it is well known for its high physical and chemical stability. There is a recent interest in this ceramic to be used as a radioactive waste form material due to its intriguing chemical and physical properties. In this study, the nano-sized fluorapatite particles were synthesized using a precipitation method and the material was characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Two well-known methods, called solution-drop and the microtome cutting, were used to prepare the sample for TEM analysis. It was found that the microtome cutting technique is advantageous for examining the particle shape and cross-sectional morphology as well as for obtaining ultra-thin samples. However, this method introduces artifacts and strong background contrast for high-resolution transmission electron microscopy (HRTEM) observation. On the other hand, phase image simulations showed that the solution-drop method is reliable and stable for HRTEM analysis. Therefore, in order to comprehensively analyze the microstructure and morphology of the nano-material, it is necessary to combine both solution-drop and microtome cutting techniques for TEM sample preparation.

  18. Marine sediment sample preparation for analysis for low concentrations of fine detrital gold

    USGS Publications Warehouse

    Clifton, H. Edward; Hubert, Arthur; Phillips, R. Lawrence

    1967-01-01

    Analyses by atomic absorption for detrital gold in more than 2,000 beach, offshore, marine-terrace, and alluvial sands from southern Oregon have shown that the values determined from raw or unconcentrated sediment containing small amounts of gold are neither reproducible nor representative of the initial sample. This difficulty results from a 'particle sparsity effect', whereby the analysis for gold in a given sample depends more upon the occurrence of random flakes of gold in the analyzed portion than upon the actual gold content of the sample. The particle sparsity effect can largely be eliminated by preparing a gold concentrate prior to analysis. A combination of sieve, gravimetric, and magnetic separation produces a satisfactory concentrate that yields accurate and reproducible analyses. In concentrates of nearly every marine and beach sand studied, the gold occurs in the nonmagnetic fraction smaller than 0.124 mm and with a specific gravity greater than 3.3. The grain size of gold in stream sediments is somewhat more variable. Analysis of concentrates provides a means of greatly increasing the sensitivity of the analytical technique in relation to the initial sample. Gold rarely exceeds 1 part per million in even the richest black sand analyzed; to establish the distribution of gold (and platinum) in marine sediments and its relationship to source and environmental factors, one commonly needs to know their content to the part per billion range. Analysis of a concentrate and recalculation to the value in the initial sample permits this degree of sensitivity.

  19. Processing, Mechanical and Optical Properties of Additive-Free ZrC Ceramics Prepared by Spark Plasma Sintering.

    PubMed

    Musa, Clara; Licheri, Roberta; Orrù, Roberto; Cao, Giacomo; Sciti, Diletta; Silvestroni, Laura; Zoli, Luca; Balbo, Andrea; Mercatelli, Luca; Meucci, Marco; Sani, Elisa

    2016-06-18

    In the present study, nearly fully dense monolithic ZrC samples are produced and broadly characterized from microstructural, mechanical and optical points of view. Specifically, 98% dense products are obtained by Spark Plasma Sintering (SPS) after 20 min dwell time at 1850 °C starting from powders preliminarily prepared by Self-propagating High-temperature Synthesis (SHS) followed by 20 min ball milling. A prolonged mechanical treatment up to 2 h of SHS powders does not lead to appreciable benefits. Vickers hardness of the resulting samples (17.5 ± 0.4 GPa) is reasonably good for monolithic ceramics, but the mechanical strength (about 250 MPa up to 1000 °C) could be further improved by suitable optimization of the starting powder characteristics. The very smoothly polished ZrC specimen subjected to optical measurements displays high absorption in the visible-near infrared region and low thermal emittance at longer wavelengths. Moreover, the sample exhibits goodspectral selectivity (2.1-2.4) in the 1000-1400 K temperature range. These preliminary results suggest that ZrC ceramics produced through the two-step SHS/SPS processing route can be considered as attractive reference materials for the development of innovative solar energy absorbers.

  20. Sample preparation for an optimized extraction of localized metabolites in lichens: Application to Pseudevernia furfuracea.

    PubMed

    Komaty, Sarah; Letertre, Marine; Dang, Huyen Duong; Jungnickel, Harald; Laux, Peter; Luch, Andreas; Carrié, Daniel; Merdrignac-Conanec, Odile; Bazureau, Jean-Pierre; Gauffre, Fabienne; Tomasi, Sophie; Paquin, Ludovic

    2016-04-01

    Lichens are symbiotic organisms known for producing unique secondary metabolites with attractive cosmetic and pharmacological properties. In this paper, we investigated three standard methods of preparation of Pseudevernia furfuracea (blender grinding, ball milling, pestle and mortar). The materials obtained were characterized by electronic microscopy, nitrogen adsorption and compared from the point of view of extraction. Their microscopic structure is related to extraction efficiency. In addition, it is shown using thalline reactions and mass spectrometry mapping (TOF-SIMS) that these metabolites are not evenly distributed throughout the organism. Particularly, atranorin (a secondary metabolite of interest) is mainly present in the cortex of P. furfuracea. Finally, using microwave assisted extraction (MAE) we obtained evidence that an appropriate preparation can increase the extraction efficiency of atranorin by a factor of five. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DUST AND SOIL SAMPLES FOR ANALYSIS OF NEUTRAL PERSISTENT ORGANIC POLLUTANTS (SOP-5.14)

    EPA Science Inventory

    This SOP summarizes the method for extracting and preparing a dust or soil sample for analysis of neutral persistent organic pollutants. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mass spectrometry.

  2. Walleye age estimation using otoliths and dorsal spines: Preparation techniques and sampling guidelines based on sex and total length

    USGS Publications Warehouse

    Dembkowski, Daniel J.; Isermann, Daniel A.; Koenigs, Ryan P.

    2017-01-01

    We used dorsal spines and otoliths from 735 Walleye Sander vitreus collected from 35 Wisconsin water bodies to evaluate whether 1) otolith and dorsal spine cross sections provided age estimates similar to simpler methods of preparation (e.g., whole otoliths and dorsal spines, cracked otoliths); and 2) between-reader precision and differences between spine and otolith ages varied in relation to total length (TL), sex, and growth rate. Ages estimated from structures prepared using simpler techniques were generally similar to ages estimated using thin sections of dorsal spines and otoliths, suggesting that, in some instances, much of the additional processing time and specialized equipment associated with thin sectioning could be avoided. Overall, between-reader precision was higher for sectioned otoliths (mean coefficient of variation [CV] = 3.28%; standard error [SE] = 0.33%) than for sectioned dorsal spines (mean CV = 9.20%; SE = 0.56%). When using sectioned otoliths for age assignment, between-reader precision did not vary between sexes or growth categories (i.e., fast, moderate, slow), but between-reader precision was higher for females than males when using sectioned dorsal spines. Dorsal spines were generally effective at replicating otolith ages for male Walleye <450 mm TL and female Walleye <600 mm TL, suggesting that dorsal spines can be used to estimate ages for male Walleye <450 mm TL and female Walleye <600 mm TL. If sex is unknown, we suggest dorsal spines be used to estimate ages for Walleye <450 mm TL, but that otoliths be used for fish >450 mm TL. Our results provide useful guidance on structure and preparation technique selection for Walleye age estimation, thereby allowing biologists to develop sampling guidelines that could be implemented using information that is always (TL) or often (sex) available at the time of fish collection.

  3. Preparation of C18 composite solid-phase microextraction fiber and its application to the determination of organochlorine pesticides in water samples.

    PubMed

    Li, Siyan; Lu, Chengwei; Zhu, Fang; Jiang, Ruifen; Ouyang, Gangfeng

    2015-05-11

    In this work, a C18 composite solid-phase microextraction (SPME) fiber was prepared with a new method and applied to the analysis of organochlorine pesticides (OCPs) in water sample. A stainless steel wire (o.d. 127 μm) was used as the substrate, and a mixture of the C18 particle (3.5 μm) and the 184 silicone was used as the coating material. During the process of fiber preparation, a section of capillary column was used to fix the mixture onto the stainless steel wire and to ensure the constant of coating thickness. The prepared fiber showed excellent thermal stability and solvent resistance. By coupling with gas chromatography-mass spectrometry (GC-MS), the fiber exhibited wide linearity (2-500 ng L(-1)) and good sensitivity for the determination of six OCPs in water samples, the OCPs tested included hexachlorobezene, trans-chlordane, cis-chlordane, o,p-DDT, p,p-DDT and mirex. Not only the extraction performance of the newly prepared fiber was more than seven times higher than those of commercial fibers, the limits of detections (LODs) (0.059-0.151 ng L(-1)) for OCPs achieved under optimized conditions were also lower than those of reported SPME methods. The fiber was successfully applied to the determination of OCPs in real water samples by using developed SPME-GC-MS method. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Urine Sample Preparation in 96-Well Filter Plates for Quantitative Clinical Proteomics

    PubMed Central

    2015-01-01

    Urine is an important, noninvasively collected body fluid source for the diagnosis and prognosis of human diseases. Liquid chromatography mass spectrometry (LC-MS) based shotgun proteomics has evolved as a sensitive and informative technique to discover candidate disease biomarkers from urine specimens. Filter-aided sample preparation (FASP) generates peptide samples from protein mixtures of cell lysate or body fluid origin. Here, we describe a FASP method adapted to 96-well filter plates, named 96FASP. Soluble urine concentrates containing ∼10 μg of total protein were processed by 96FASP and LC-MS resulting in 700–900 protein identifications at a 1% false discovery rate (FDR). The experimental repeatability, as assessed by label-free quantification and Pearson correlation analysis for shared proteins among replicates, was high (R ≥ 0.97). Application to urinary pellet lysates which is of particular interest in the context of urinary tract infection analysis was also demonstrated. On average, 1700 proteins (±398) were identified in five experiments. In a pilot study using 96FASP for analysis of eight soluble urine samples, we demonstrated that protein profiles of technical replicates invariably clustered; the protein profiles for distinct urine donors were very different from each other. Robust, highly parallel methods to generate peptide mixtures from urine and other body fluids are critical to increase cost-effectiveness in clinical proteomics projects. This 96FASP method has potential to become a gold standard for high-throughput quantitative clinical proteomics. PMID:24797144

  5. Procedure for chromatography involving sample solvent with higher elution strength than the mobile phase.

    PubMed

    Patil, Nitin S; Mendhe, Rakesh B; Sankar, Ajeet A; Iyer, Harish

    2008-01-11

    In preparative chromatography, often the solubility of the sample in the mobile phase is limited, making the mobile phase unsuitable as a solvent for preparation of load. Generally, solvents that have high solubility for the sample also have higher elution strengths than the mobile phase. Additionally, at high loading volumes, these strong sample solvents are known to adversely affect the band profiles leading to poor chromatographic performance. Here, we show that controlling the mobile phase strength during loading and post-load elution resulted in improved band profiles when the sample solvent was stronger than the mobile phase. Such an approach improves performance in preparative chromatography by allowing either higher sample loading or higher organic content in mobile phase (without loss of yield). Alternately, the approach can be used for improvement in performance by increase in yield or product purity.

  6. Rapid filtration separation-based sample preparation method for Bacillus spores in powdery and environmental matrices.

    PubMed

    Isabel, Sandra; Boissinot, Maurice; Charlebois, Isabelle; Fauvel, Chantal M; Shi, Lu-E; Lévesque, Julie-Christine; Paquin, Amélie T; Bastien, Martine; Stewart, Gale; Leblanc, Eric; Sato, Sachiko; Bergeron, Michel G

    2012-03-01

    Authorities frequently need to analyze suspicious powders and other samples for biothreat agents in order to assess environmental safety. Numerous nucleic acid detection technologies have been developed to detect and identify biowarfare agents in a timely fashion. The extraction of microbial nucleic acids from a wide variety of powdery and environmental samples to obtain a quality level adequate for these technologies still remains a technical challenge. We aimed to develop a rapid and versatile method of separating bacteria from these samples and then extracting their microbial DNA. Bacillus atrophaeus subsp. globigii was used as a simulant of Bacillus anthracis. We studied the effects of a broad variety of powdery and environmental samples on PCR detection and the steps required to alleviate their interference. With a benchmark DNA extraction procedure, 17 of the 23 samples investigated interfered with bacterial lysis and/or PCR-based detection. Therefore, we developed the dual-filter method for applied recovery of microbial particles from environmental and powdery samples (DARE). The DARE procedure allows the separation of bacteria from contaminating matrices that interfere with PCR detection. This procedure required only 2 min, while the DNA extraction process lasted 7 min, for a total of <10 min. This sample preparation procedure allowed the recovery of cleaned bacterial spores and relieved detection interference caused by a wide variety of samples. Our procedure was easily completed in a laboratory facility and is amenable to field application and automation.

  7. Rapid Filtration Separation-Based Sample Preparation Method for Bacillus Spores in Powdery and Environmental Matrices

    PubMed Central

    Isabel, Sandra; Boissinot, Maurice; Charlebois, Isabelle; Fauvel, Chantal M.; Shi, Lu-E; Lévesque, Julie-Christine; Paquin, Amélie T.; Bastien, Martine; Stewart, Gale; Leblanc, Éric; Sato, Sachiko

    2012-01-01

    Authorities frequently need to analyze suspicious powders and other samples for biothreat agents in order to assess environmental safety. Numerous nucleic acid detection technologies have been developed to detect and identify biowarfare agents in a timely fashion. The extraction of microbial nucleic acids from a wide variety of powdery and environmental samples to obtain a quality level adequate for these technologies still remains a technical challenge. We aimed to develop a rapid and versatile method of separating bacteria from these samples and then extracting their microbial DNA. Bacillus atrophaeus subsp. globigii was used as a simulant of Bacillus anthracis. We studied the effects of a broad variety of powdery and environmental samples on PCR detection and the steps required to alleviate their interference. With a benchmark DNA extraction procedure, 17 of the 23 samples investigated interfered with bacterial lysis and/or PCR-based detection. Therefore, we developed the dual-filter method for applied recovery of microbial particles from environmental and powdery samples (DARE). The DARE procedure allows the separation of bacteria from contaminating matrices that interfere with PCR detection. This procedure required only 2 min, while the DNA extraction process lasted 7 min, for a total of <10 min. This sample preparation procedure allowed the recovery of cleaned bacterial spores and relieved detection interference caused by a wide variety of samples. Our procedure was easily completed in a laboratory facility and is amenable to field application and automation. PMID:22210204

  8. Rapid LC-MS method for the detection of common fragrances in personal care products without sample preparation.

    PubMed

    Famiglini, Giorgio; Termopoli, Veronica; Palma, Pierangela; Capriotti, Fabiana; Cappiello, Achille

    2014-05-01

    An LC-MS method for the analysis of personal care and household products without sample preparation is presented. The method takes advantage of the Direct-electron ionization (EI) LC-MS interface for the quantitation of principal components, as well as for the identification of unknown or undeclared ingredients. The technique has proven its inertness toward matrix effects and the electron ionization allows quantitation and library identification. Commercially available products (shower gel, perfume, and hand cream) were diluted with methanol and injected directly into a nano-LC column. Limonene, linalool, and citral were selected as target compounds because of their use as fragrances in toiletry and detergent products. These and all other fragrances are commonly determined with GC-MS analysis, prior to sample cleanup, a procedure that can lead to analytes loss. The selected compounds are not detected with ESI because of their poor or very low response. Figures of merit and validation studies were executed and special attention was devoted to matrix-effects evaluation, because a sample preparation procedure is not involved. No matrix effects were observed, and the repeatability was excellent even after several weeks of operation. Products composition was investigated in full scan mode to determine the presence of unknown or not listed ingredients. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DUST AND SOIL SAMPLES FOR ANALYSIS OF POLAR PERSISTENT ORGANIC POLLUTANTS (SOP-5.15)

    EPA Science Inventory

    The method for extracting and preparing a dust or soil sample for analysis of polar persistent organic pollutants is summarized in this SOP. It covers the extraction, concentration, and derivatization of samples that are to be analyzed by gas chromatography/mass spectrometry.

  10. One Sample, One Shot - Evaluation of sample preparation protocols for the mass spectrometric proteome analysis of human bile fluid without extensive fractionation.

    PubMed

    Megger, Dominik A; Padden, Juliet; Rosowski, Kristin; Uszkoreit, Julian; Bracht, Thilo; Eisenacher, Martin; Gerges, Christian; Neuhaus, Horst; Schumacher, Brigitte; Schlaak, Jörg F; Sitek, Barbara

    2017-02-10

    The proteome analysis of bile fluid represents a promising strategy to identify biomarker candidates for various diseases of the hepatobiliary system. However, to obtain substantive results in biomarker discovery studies large patient cohorts necessarily need to be analyzed. Consequently, this would lead to an unmanageable number of samples to be analyzed if sample preparation protocols with extensive fractionation methods are applied. Hence, the performance of simple workflows allowing for "one sample, one shot" experiments have been evaluated in this study. In detail, sixteen different protocols implying modifications at the stages of desalting, delipidation, deglycosylation and tryptic digestion have been examined. Each method has been individually evaluated regarding various performance criteria and comparative analyses have been conducted to uncover possible complementarities. Here, the best performance in terms of proteome coverage has been assessed for a combination of acetone precipitation with in-gel digestion. Finally, a mapping of all obtained protein identifications with putative biomarkers for hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) revealed several proteins easily detectable in bile fluid. These results can build the basis for future studies with large and well-defined patient cohorts in a more disease-related context. Human bile fluid is a proximal body fluid and supposed to be a potential source of disease markers. However, due to its biochemical composition, the proteome analysis of bile fluid still represents a challenging task and is therefore mostly conducted using extensive fractionation procedures. This in turn leads to a high number of mass spectrometric measurements for one biological sample. Considering the fact that in order to overcome the biological variability a high number of biological samples needs to be analyzed in biomarker discovery studies, this leads to the dilemma of an unmanageable number of

  11. Imaging of fullerene-like structures in CNx thin films by electron microscopy; sample preparation artefacts due to ion-beam milling.

    PubMed

    Czigány, Zs; Neidhardt, J; Brunell, I F; Hultman, L

    2003-04-01

    The microstructure of CN(x) thin films, deposited by reactive magnetron sputtering, was investigated by transmission electron microscopy (TEM) at 200kV in plan-view and cross-sectional samples. Imaging artefacts arise in high-resolution TEM due to overlap of nm-sized fullerene-like features for specimen thickness above 5nm. The thinnest and apparently artefact-free areas were obtained at the fracture edges of plan-view specimens floated-off from NaCl substrates. Cross-sectional samples were prepared by ion-beam milling at low energy to minimize sample preparation artefacts. The depth of the ion-bombardment-induced surface amorphization was determined by TEM cross sections of ion-milled fullerene-like CN(x) surfaces. The thickness of the damaged surface layer at 5 degrees grazing incidence was 13 and 10nm at 3 and 0.8keV, respectively, which is approximately three times larger than that observed on Si prepared under the same conditions. The shallowest damage depth, observed for 0.25keV, was less than 1nm. Chemical changes due to N loss and graphitization were also observed by X-ray photoelectron spectroscopy. As a consequence of chemical effects, sputtering rates of CN(x) films were similar to that of Si, which enables relatively fast ion-milling procedure compared to carbon compounds. No electron beam damage of fullerene-like CN(x) was observed at 200kV.

  12. Large-volume injection of sample diluents not miscible with the mobile phase as an alternative approach in sample preparation for bioanalysis: an application for fenspiride bioequivalence.

    PubMed

    Medvedovici, Andrei; Udrescu, Stefan; Albu, Florin; Tache, Florentin; David, Victor

    2011-09-01

    Liquid-liquid extraction of target compounds from biological matrices followed by the injection of a large volume from the organic layer into the chromatographic column operated under reversed-phase (RP) conditions would successfully combine the selectivity and the straightforward character of the procedure in order to enhance sensitivity, compared with the usual approach of involving solvent evaporation and residue re-dissolution. Large-volume injection of samples in diluents that are not miscible with the mobile phase was recently introduced in chromatographic practice. The risk of random errors produced during the manipulation of samples is also substantially reduced. A bioanalytical method designed for the bioequivalence of fenspiride containing pharmaceutical formulations was based on a sample preparation procedure involving extraction of the target analyte and the internal standard (trimetazidine) from alkalinized plasma samples in 1-octanol. A volume of 75 µl from the octanol layer was directly injected on a Zorbax SB C18 Rapid Resolution, 50 mm length × 4.6 mm internal diameter × 1.8 µm particle size column, with the RP separation being carried out under gradient elution conditions. Detection was made through positive ESI and MS/MS. Aspects related to method development and validation are discussed. The bioanalytical method was successfully applied to assess bioequivalence of a modified release pharmaceutical formulation containing 80 mg fenspiride hydrochloride during two different studies carried out as single-dose administration under fasting and fed conditions (four arms), and multiple doses administration, respectively. The quality attributes assigned to the bioanalytical method, as resulting from its application to the bioequivalence studies, are highlighted and fully demonstrate that sample preparation based on large-volume injection of immiscible diluents has an increased potential for application in bioanalysis.

  13. Molecularly imprinted polymeric stir bar: Preparation and application for the determination of naftopidil in plasma and urine samples.

    PubMed

    Peng, Jun; Xiao, Deli; He, Hua; Zhao, Hongyan; Wang, Cuixia; Shi, Tian; Shi, Kexin

    2016-01-01

    In this study, molecularly imprinting technology and stir bar absorption technology were combined to develop a microextraction approach based on a molecularly imprinted polymeric stir bar. The molecularly imprinted polymer stir bar has a high performance, is specific, economical, and simple to prepare. The obtained naftopidil-imprinted polymer-coated bars could simultaneously agitate and adsorb naftopidil in the sample solution. The ratio of template/monomer/cross-linker and conditions of template removal were optimized to prepare a stir bar with highly efficient adsorption. Fourier transform infrared spectroscopy, scanning electron microscopy, selectivity, and extraction capacity experiments showed that the molecularly imprinted polymer stir bar was prepared successfully. To utilize the molecularly imprinted polymer stir bar for the determination of naftopidil in complex body fluid matrices, the extraction time, stirring speed, eluent, and elution time were optimized. The limits of detection of naftopidil in plasma and urine sample were 7.5 and 4.0 ng/mL, respectively, and the recoveries were in the range of 90-112%. The within-run precision and between-run precision were acceptable (relative standard deviation <7%). These data demonstrated that the molecularly imprinted polymeric stir bar based microextraction with high-performance liquid chromatography was a convenient, rapid, efficient, and specific method for the precise determination of trace naftopidil in clinical analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Sample preparation and UHPLC-FD analysis of pteridines in human urine.

    PubMed

    Tomšíková, H; Solich, P; Nováková, L

    2014-07-01

    Elevated levels of pteridines can indicate the activation of cellular immune system by certain diseases. No work dealing with the simultaneous determination of urinary neopterin, biopterin and their reduced forms has been published. Therefore, a new SPE-UHPLC-FD method for the analysis of these compounds has been developed. The main emphasis was put on the stability of dihydroforms during the sample processing and storage. As a stabilizing agent, dithiothreitol, at various concentrations, and various pH values (3.8-9.8) of working solutions were tested. Chromatographic separation was performed under HILIC isocratic conditions on BEH Amide column. The method was linear for the calibration standard solutions in the range of 10-10,000 ng/ml (dihydroforms) and 0.5-1000 ng/ml (oxidized forms), and for real samples in the range of 25-1000 ng/ml (dihydroforms) and 1-100 ng/ml (oxidized forms). The development of a new SPE sample preparation method was carried out on different types of sorbents (based on a mixed-mode cation exchange, porous graphitic carbon and a polymer comprising hydrophilic and hydrophobic components). Final validation was performed on a MCAX SPE column. Method accuracy ranged from 76.9 to 121.9%. The intra- and inter-day precision did not exceed 10.7%. The method provided high sensitivity for the use in routine clinical measurements of urine (LLOQ 1 ng/ml for oxidized forms and 25 ng/ml for dihydroforms). Average concentrations of biopterin, neopterin, and dihydrobiopterin found in urine of healthy persons were related to the mol of creatinine (66.8, 142.3, and 257.3 μmol/mol of creatinine, respectively) which corresponded to the literature data. The concentration of dihydroneopterin obtained using our method was 98.8 μmol/mol of creatinine. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Glass sample preparation and performance investigations. [solar x-ray imager

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1992-01-01

    This final report details the work performed under this delivery order from April 1991 through April 1992. The currently available capabilities for integrated optical performance modeling at MSFC for large and complex systems such as AXAF were investigated. The Integrated Structural Modeling (ISM) program developed by Boeing for the U.S. Air Force was obtained and installed on two DECstations 5000 at MSFC. The structural, thermal and optical analysis programs available in ISM were evaluated. As part of the optomechanical engineering activities, technical support was provided in the design of support structure, mirror assembly, filter wheel assembly and material selection for the Solar X-ray Imager (SXI) program. As part of the fabrication activities, a large number of zerodur glass samples were prepared in different sizes and shapes for acid etching, coating and polishing experiments to characterize the subsurface damage and stresses produced by the grinding and polishing operations. Various optical components for AXAF video microscope and the x-ray test facility were also fabricated. A number of glass fabrication and test instruments such as a scatter plate interferometer, a gravity feed saw and some phenolic cutting blades were fabricated, integrated and tested.

  16. Properties of ZnO nanocrystals prepared by radiation method

    NASA Astrophysics Data System (ADS)

    Čuba, Václav; Gbur, Tomáš; Múčka, Viliam; Nikl, Martin; Kučerková, Romana; Pospíšil, Milan; Jakubec, Ivo

    2010-01-01

    Zinc oxide nanoparticles were prepared by irradiation of aqueous solutions containing zinc(II) ions, propan-2-ol, polyvinyl alcohol, and hydrogen peroxide. Zinc oxide was found in solid phase either directly after irradiation, or after additional heat treatment. Various physicochemical parameters, including scintillation properties of prepared materials, were studied. After decomposition of impurities and annealing of oxygen vacancies, the samples showed intensive emission in visible spectral range and well-shaped exciton luminescence at 390-400 nm. The best scintillating properties had zinc oxide prepared from aqueous solutions containing zinc formate as initial precursor and hydrogen peroxide. Size of the crystalline particles ranged from tens to hundreds nm, depending on type of irradiated solution and post-irradiation thermal treatment.

  17. Portable sample preparation and analysis system for micron and sub-micron particle characterization using light scattering and absorption spectroscopy

    DOEpatents

    Stark, Peter C [Los Alamos, NM; Zurek, Eduardo [Barranquilla, CO; Wheat, Jeffrey V [Fort Walton Beach, FL; Dunbar, John M [Santa Fe, NM; Olivares, Jose A [Los Alamos, NM; Garcia-Rubio, Luis H [Temple Terrace, FL; Ward, Michael D [Los Alamos, NM

    2011-07-26

    There is provided a method and device for remote sampling, preparation and optical interrogation of a sample using light scattering and light absorption methods. The portable device is a filtration-based device that removes interfering background particle material from the sample matrix by segregating or filtering the chosen analyte from the sample solution or matrix while allowing the interfering background particles to be pumped out of the device. The segregated analyte is then suspended in a diluent for analysis. The device is capable of calculating an initial concentration of the analyte, as well as diluting the analyte such that reliable optical measurements can be made. Suitable analytes include cells, microorganisms, bioparticles, pathogens and diseases. Sample matrixes include biological fluids such as blood and urine, as well as environmental samples including waste water.

  18. A novel sample preparation method using rapid nonheated saponification method for the determination of cholesterol in emulsified foods.

    PubMed

    Jeong, In-Seek; Kwak, Byung-Man; Ahn, Jang-Hyuk; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

    2012-10-01

    In this study, nonheated saponification was employed as a novel, rapid, and easy sample preparation method for the determination of cholesterol in emulsified foods. Cholesterol content was analyzed using gas chromatography with a flame ionization detector (GC-FID). The cholesterol extraction method was optimized for maximum recovery from baby food and infant formula. Under these conditions, the optimum extraction solvent was 10 mL ethyl ether per 1 to 2 g sample, and the saponification solution was 0.2 mL KOH in methanol. The cholesterol content in the products was determined to be within the certified range of certified reference materials (CRMs), NIST SRM 1544 and SRM 1849. The results of the recovery test performed using spiked materials were in the range of 98.24% to 99.45% with an relative standard devitation (RSD) between 0.83% and 1.61%. This method could be used to reduce sample pretreatment time and is expected to provide an accurate determination of cholesterol in emulsified food matrices such as infant formula and baby food. A novel, rapid, and easy sample preparation method using nonheated saponification was developed for cholesterol detection in emulsified foods. Recovery tests of CRMs were satisfactory, and the recoveries of spiked materials were accurate and precise. This method was effective and decreased the time required for analysis by 5-fold compared to the official method. © 2012 Institute of Food Technologists®

  19. Processing, Mechanical and Optical Properties of Additive-Free ZrC Ceramics Prepared by Spark Plasma Sintering

    PubMed Central

    Musa, Clara; Licheri, Roberta; Orrù, Roberto; Cao, Giacomo; Sciti, Diletta; Silvestroni, Laura; Zoli, Luca; Balbo, Andrea; Mercatelli, Luca; Meucci, Marco; Sani, Elisa

    2016-01-01

    In the present study, nearly fully dense monolithic ZrC samples are produced and broadly characterized from microstructural, mechanical and optical points of view. Specifically, 98% dense products are obtained by Spark Plasma Sintering (SPS) after 20 min dwell time at 1850 °C starting from powders preliminarily prepared by Self-propagating High-temperature Synthesis (SHS) followed by 20 min ball milling. A prolonged mechanical treatment up to 2 h of SHS powders does not lead to appreciable benefits. Vickers hardness of the resulting samples (17.5 ± 0.4 GPa) is reasonably good for monolithic ceramics, but the mechanical strength (about 250 MPa up to 1000 °C) could be further improved by suitable optimization of the starting powder characteristics. The very smoothly polished ZrC specimen subjected to optical measurements displays high absorption in the visible-near infrared region and low thermal emittance at longer wavelengths. Moreover, the sample exhibits goodspectral selectivity (2.1–2.4) in the 1000–1400 K temperature range. These preliminary results suggest that ZrC ceramics produced through the two-step SHS/SPS processing route can be considered as attractive reference materials for the development of innovative solar energy absorbers. PMID:28773611

  20. An efficient and sensitive method for preparing cDNA libraries from scarce biological samples

    PubMed Central

    Sterling, Catherine H.; Veksler-Lublinsky, Isana; Ambros, Victor

    2015-01-01

    The preparation and high-throughput sequencing of cDNA libraries from samples of small RNA is a powerful tool to quantify known small RNAs (such as microRNAs) and to discover novel RNA species. Interest in identifying the small RNA repertoire present in tissues and in biofluids has grown substantially with the findings that small RNAs can serve as indicators of biological conditions and disease states. Here we describe a novel and straightforward method to clone cDNA libraries from small quantities of input RNA. This method permits the generation of cDNA libraries from sub-picogram quantities of RNA robustly, efficiently and reproducibly. We demonstrate that the method provides a significant improvement in sensitivity compared to previous cloning methods while maintaining reproducible identification of diverse small RNA species. This method should have widespread applications in a variety of contexts, including biomarker discovery from scarce samples of human tissue or body fluids. PMID:25056322

  1. Optical biosensor system with integrated microfluidic sample preparation and TIRF based detection

    NASA Astrophysics Data System (ADS)

    Gilli, Eduard; Scheicher, Sylvia R.; Suppan, Michael; Pichler, Heinz; Rumpler, Markus; Satzinger, Valentin; Palfinger, Christian; Reil, Frank; Hajnsek, Martin; Köstler, Stefan

    2013-05-01

    There is a steadily growing demand for miniaturized bioanalytical devices allowing for on-site or point-of-care detection of biomolecules or pathogens in applications like diagnostics, food testing, or environmental monitoring. These, so called labs-on-a-chip or micro-total analysis systems (μ-TAS) should ideally enable convenient sample-in - result-out type operation. Therefore, the entire process from sample preparation, metering, reagent incubation, etc. to detection should be performed on a single disposable device (on-chip). In the early days such devices were mainly fabricated using glass or silicon substrates and adapting established fabrication technologies from the electronics and semiconductor industry. More recently, the development focuses on the use of thermoplastic polymers as they allow for low-cost high volume fabrication of disposables. One of the most promising materials for the development of plastic based lab-on-achip systems are cyclic olefin polymers and copolymers (COP/COC) due to their excellent optical properties (high transparency and low autofluorescence) and ease of processing. We present a bioanalytical system for whole blood samples comprising a disposable plastic chip based on TIRF (total internal reflection fluorescence) optical detection. The chips were fabricated by compression moulding of COP and microfluidic channels were structured by hot embossing. These microfluidic structures integrate several sample pretreatment steps. These are the separation of erythrocytes, metering of sample volume using passive valves, and reagent incubation for competitive bioassays. The surface of the following optical detection zone is functionalized with specific capture probes in an array format. The plastic chips comprise dedicated structures for simple and effective coupling of excitation light from low-cost laser diodes. This enables TIRF excitation of fluorescently labeled probes selectively bound to detection spots at the microchannel surface

  2. Evidence of a miscibility gap in the FeTe1-xSex polycrystalline samples prepared with a melting process

    NASA Astrophysics Data System (ADS)

    Sala, A.; Palenzona, A.; Bernini, C.; Caglieris, F.; Cimberle, M. R.; Ferdeghini, C.; Lamura, G.; Martinelli, A.; Pani, M.; Hecher, J.; Eisterer, M.; Putti, M.

    2014-05-01

    The study of overdoped FeTe1-xSex (0.5 < x < 1) polycrystalline superconductor samples is reported. The samples were prepared using a melting technique previously developed by our group. Increasing the Se content a phase separation related to the formation of FeSe inside the Fe(Se,Te) phase happens, as demonstrated by structural analysis and magnetic characterization. The proposed phase separation picture is likely the fingerprint of a miscibility gap in the Fe(Se,Te) system.

  3. A dilute-and-shoot sample preparation strategy for new and used lubricating oils for Ca, P, S and Zn determination by total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Mota, Mariana F. B.; Gama, Ednilton M.; Rodrigues, Gabrielle de C.; Rodrigues, Guilherme D.; Nascentes, Clésia C.; Costa, Letícia M.

    2018-01-01

    In this work, a dilute-and-shoot method was developed for Ca, P, S and Zn determination in new and used lubricating oil samples by total reflection X-ray fluorescence (TXRF). The oil samples were diluted with organic solvents followed by addition of yttrium as internal standard and the TXRF measurements were performed after solvent evaporation. The method was optimized using an interlaboratorial reference material. The experimental parameters evaluated were sample volume (50 or 100 μL), measurement time (250 or 500 s) and volume deposited on the quartz glass sample carrier (5 or 10 μL). All of them were evaluated and optimized using xylene, kerosene and hexane. Analytical figures of merit (accuracy, precision, limit of detection and quantification) were used to evaluate the performance of the analytical method for all solvents. The recovery rates varied from 99 to 111% and the relative standard deviation remained between 1.7% and 10% (n = 8). For all elements, the results obtained by applying the new method were in agreement with the certified value. After the validation step, the method was applied for Ca, P, S and Zn quantification in eight new and four used lubricating oil samples, for all solvents. The concentration of the elements in the samples varied in the ranges of 1620-3711 mg L- 1 for Ca, 704-1277 mg L- 1 for P, 2027-9147 mg L- 1 for S, and 898-1593 mg L- 1 for Zn. The association of TXRF with a dilute-and-shoot sample preparation strategy was efficient for Ca, P, S and Zn determination in lubricating oils, presenting accurate results. Additionally, the time required for analysis is short, the reagent volumes are low minimizing waste generation, and the technique does not require calibration curves.

  4. An integrated direct loop-mediated isothermal amplification microdevice incorporated with an immunochromatographic strip for bacteria detection in human whole blood and milk without a sample preparation step.

    PubMed

    Lee, Dohwan; Kim, Yong Tae; Lee, Jee Won; Kim, Do Hyun; Seo, Tae Seok

    2016-05-15

    We have developed an integrated direct loop-mediated isothermal amplification (Direct LAMP) microdevice incorporated with an immunochromatographic strip (ICS) to identify bacteria contaminated in real samples. The Direct LAMP is a novel isothermal DNA amplification technique which does not require thermal cycling steps as well as any sample preparation steps such as cell lysis and DNA extraction for amplifying specific target genes. In addition, the resultant amplicons were colorimetrically detected on the ICS, thereby enabling the entire genetic analysis process to be simplified. The two functional units (Direct LAMP and ICS) were integrated on a single device without use of the tedious and complicated microvalve and tubing systems. The utilization of a slidable plate allows us to manipulate the fluidic control in the microchannels manually and the sequential operation of the Direct LAMP and ICS detection could be performed by switching the slidable plate to each functional unit. Thus, the combination of the direct isothermal amplification without any sample preparation and thermal cycling steps, the ICS based amplicon detection by naked eyes, and the slidable plate to eliminate the microvalves in the integrated microdevice would be an ideal platform for point-of-care DNA diaganotics. On the integrated Direct LAMP-ICS microdevice, we could analyze Staphylococcus aureus (S. aureus) and Escherichia coli O157:H7 (E. coli O157:H7) contaminated in human whole blood or milk at a single-cell level within 1h. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. A Highly Flexible, Automated System Providing Reliable Sample Preparation in Element- and Structure-Specific Measurements.

    PubMed

    Vorberg, Ellen; Fleischer, Heidi; Junginger, Steffen; Liu, Hui; Stoll, Norbert; Thurow, Kerstin

    2016-10-01

    Life science areas require specific sample pretreatment to increase the concentration of the analytes and/or to convert the analytes into an appropriate form for the detection and separation systems. Various workstations are commercially available, allowing for automated biological sample pretreatment. Nevertheless, due to the required temperature, pressure, and volume conditions in typical element and structure-specific measurements, automated platforms are not suitable for analytical processes. Thus, the purpose of the presented investigation was the design, realization, and evaluation of an automated system ensuring high-precision sample preparation for a variety of analytical measurements. The developed system has to enable system adaption and high performance flexibility. Furthermore, the system has to be capable of dealing with the wide range of required vessels simultaneously, allowing for less cost and time-consuming process steps. However, the system's functionality has been confirmed in various validation sequences. Using element-specific measurements, the automated system was up to 25% more precise compared to the manual procedure and as precise as the manual procedure using structure-specific measurements. © 2015 Society for Laboratory Automation and Screening.

  6. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DERMAL WIPE AND SURFACE WIPE SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.27)

    EPA Science Inventory

    The method for extracting and preparing a dermal or surface wipe sample for analysis of acidic persistent organic pollutants is summarized in this standard operating procedure. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mas...

  7. Development of autoclavable addition type polyimides

    NASA Technical Reports Server (NTRS)

    Jones, R. J.; Vaughan, R. W.; Orell, M. K.; Sheppard, C. H.

    1974-01-01

    Two highly promising approaches to yield autoclavable addition-type polyimides were identified and evaluated in the program. Conditions were established for autoclave preparation of Hercules HMS graphite fiber reinforced composites in the temperature range of 473 K to 505 K under an applied pressure of 0.7 MN/m2 (100 psi) for time durations up to four hours. Upon oven postcure in air at 589 K, composite samples demonstrated high mechanical property retention at 561 K after isothermal aging in air for 1000 hours. Promise was shown for shorter term mechanical property retention at 589 K upon exposure in air at this temperature.

  8. An international marine-atmospheric {sup 222}Rn measurement intercomparison in Bermuda. Part 1: NIST calibration and methodology for standardized sample additions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Colle, R.; Unterweger, M.P.; Hodge, P.A.

    1996-01-01

    As part of an international {sup 222}Rn measurement intercomparison conducted at Bermuda in October 1991, NIST provided standardized sample additions of known, but undisclosed (blind) {sup 222}Rn concentrations that could be related to US national standards. The standardized sample additions were obtained with a calibrated {sup 226}Ra source and a specially-designed manifold used to obtain well-known dilution factors from simultaneous flow-rate measurements. The additions were introduced over sampling periods of several hours (typically 4 h) into a common streamline on a sampling tower used by the participating laboratories for their measurements. The standardized {sup 222}Rn activity concentrations for the intercomparisonmore » ranged from approximately 2.5 Bq {center_dot} m{sup {minus}3} to 35 Bq {center_dot} m{sup {minus}3} (of which the lower end of this range approached concentration levels for ambient Bermudian air) and had overall uncertainties, approximating a 3 standard deviation uncertainty interval, of about 6% to 13%. This paper describes the calibration and methodology for the standardized sample additions.« less

  9. Improved sample preparation for GC-MS-SIM analysis of ethyl carbamate in wine.

    PubMed

    Nóbrega, Ian C C; Pereira, Giuliano E; Silva, Marileide; Pereira, Elainy V S; Medeiros, Marcelo M; Telles, Danuza L; Albuquerque, Eden C; Oliveira, Juliane B; Lachenmeier, Dirk W

    2015-06-15

    An improved sample preparation procedure for analysis of carcinogenic ethyl carbamate (EC) in wine by GC-MS-SIM is proposed. Differences over AOAC reference procedure were: (1) use of EC-d5 as internal standard instead of less similar propyl carbamate; (2) extraction by diethyl ether instead of more toxic dichloromethane, and (3) concentration by vacuum automated parallel evaporation instead of more time and work consuming rotary evaporation. Mean recovery was 104.4%, intraday precision was 6.7% (3.4 μg L(-)(1)) and 1.7% (88.5 μg L(-)(1)), regression coefficient was 0.999 in the linear working range of 3-89 μg L(-)(1), and limits of detection and quantification were 0.4 and 1.2 μg L(-)(1). Applicability was demonstrated by analysis (in triplicate) of 5 wine samples. EC concentration ranged from 5.2 ± 0.2 to 29.4 ± 1.5 μg L(-)(1). The analytical method is selective, accurate, repeatable, linear, and has similar method performance as the reference method along with the several mentioned advantages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Sample preparation of sewage sludge and soil samples for the determination of polycyclic aromatic hydrocarbons based on one-pot microwave-assisted saponification and extraction.

    PubMed

    Pena, M Teresa; Pensado, Luis; Casais, M Carmen; Mejuto, M Carmen; Cela, Rafael

    2007-04-01

    A microwave-assisted sample preparation (MASP) procedure was developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge and soil samples. The procedure involved the simultaneous microwave-assisted extraction of PAHs with n-hexane and the hydrolysis of samples with methanolic potassium hydroxide. Because of the complex nature of the samples, the extracts were submitted to further cleaning with silica and Florisil solid-phase extraction cartridges connected in series. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, were considered in the study. Quantification limits obtained for all of these compounds (between 0.4 and 14.8 microg kg(-1) dry mass) were well below of the limits recommended in the USA and EU. Overall recovery values ranged from 60 to 100%, with most losses being due to evaporation in the solvent exchange stages of the procedure, although excellent extraction recoveries were obtained. Validation of the accuracy was carried out with BCR-088 (sewage sludge) and BCR-524 (contaminated industrial soil) reference materials.

  11. Multiple double cross-section transmission electron microscope sample preparation of specific sub-10 nm diameter Si nanowire devices.

    PubMed

    Gignac, Lynne M; Mittal, Surbhi; Bangsaruntip, Sarunya; Cohen, Guy M; Sleight, Jeffrey W

    2011-12-01

    The ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.

  12. Analysis and comparison of focused ion beam milling and vibratory polishing sample surface preparation methods for porosity study of U-Mo plate fuel for research and test reactors.

    PubMed

    Westman, Bjorn; Miller, Brandon; Jue, Jan-Fong; Aitkaliyeva, Assel; Keiser, Dennis; Madden, James; Tucker, Julie D

    2018-07-01

    Uranium-Molybdenum (U-Mo) low enriched uranium (LEU) fuels are a promising candidate for the replacement of high enriched uranium (HEU) fuels currently in use in a high power research and test reactors around the world. Contemporary U-Mo fuel sample preparation uses focused ion beam (FIB) methods for analysis of fission gas porosity. However, FIB possess several drawbacks, including reduced area of analysis, curtaining effects, and increased FIB operation time and cost. Vibratory polishing is a well understood method for preparing large sample surfaces with very high surface quality. In this research, fission gas porosity image analysis results are compared between samples prepared using vibratory polishing and FIB milling to assess the effectiveness of vibratory polishing for irradiated fuel sample preparation. Scanning electron microscopy (SEM) imaging was performed on sections of irradiated U-Mo fuel plates and the micrographs were analyzed using a fission gas pore identification and measurement script written in MatLab. Results showed that the vibratory polishing method is preferentially removing material around the edges of the pores, causing the pores to become larger and more rounded, leading to overestimation of the fission gas porosity size. Whereas, FIB preparation tends to underestimate due to poor micrograph quality and surface damage leading to inaccurate segmentations. Despite the aforementioned drawbacks, vibratory polishing remains a valid method for porosity analysis sample preparation, however, improvements should be made to reduce the preferential removal of material surrounding pores in order to minimize the error in the porosity measurements. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. The Preparation and Simple Analysis of a Clay Nanoparticle Composite Hydrogel

    ERIC Educational Resources Information Center

    Warren, David S.; Sutherland, Sam P. H.; Kao, Jacqueline Y.; Weal, Geoffrey R.; Mackay, Sean M.

    2017-01-01

    Samples of a composite hydrogel incorporating clay (Laponite XLG and S-482) nanoparticles were prepared using N-isopropylacrylamide. The hydrogels were formed via a radical-initiated addition polymerization using potassium persulfate and N,N,N',N'-tetramethylethylenediamine. Students then measured the force required to stretch the gels and…

  14. TEMPO addition into pre-irradiated fluoropolymers and living-radical graft polymerization of styrene for preparation of polymer electrolyte membranes

    NASA Astrophysics Data System (ADS)

    Sawada, Shin-ichi; Suzuki, Akihiro; Terai, Takayuki; Maekawa, Yasunari

    2010-04-01

    We prepared proton exchange membranes (PEMs) by 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO)-mediated living-radical graft polymerization (LRGP) of styrene into fluoropolymer films and subsequent sulfonation. Poly(vinylidene fluoride) (PVDF) and poly(ethylene- co-tetrafluoroethylene) (ETFE) films were first irradiated and then treated with TEMPO solutions in various solvents. TEMPO addition was confirmed by the test of styrene grafting into TEMPO-treated films at 60 °C, at which the LRGP never proceeds. This test enabled us to differentiate the LRGP from the conventional graft polymerization. In order to gain a deep insight about TEMPO-addition reaction, the TEMPO-penetration behavior into the base polymer films was examined by a permeation experiment and computer simulation. Xylene and dioxane were appropriate solvents for the complete introduction of TEMPO into PVDF and ETFE films, respectively. Then, the LRGP of styrene was performed based on the fully TEMPO-capped films at 125 °C with various solvents. By using an alcoholic solvent, the degree of grafting was enhanced and it reached a maximum of 38%. This grafted film was sulfonated to prepare a PEM showing an ion exchange capacity of 2.2 meq/g and proton conductivity of 1.6×10 -1 S/cm.

  15. Nearly 1000 Protein Identifications from 50 ng of Xenopus laevis Zygote Homogenate Using Online Sample Preparation on a Strong Cation Exchange Monolith Based Microreactor Coupled with Capillary Zone Electrophoresis.

    PubMed

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Cox, Olivia F; Huber, Paul W; Dovichi, Norman J

    2016-01-05

    A sulfonate-silica hybrid strong cation exchange monolith microreactor was synthesized and coupled to a linear polyacrylamide coated capillary for online sample preparation and capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) bottom-up proteomic analysis. The protein sample was loaded onto the microreactor in an acidic buffer. After online reduction, alkylation, and digestion with trypsin, the digests were eluted with 200 mM ammonium bicarbonate at pH 8.2 for CZE-MS/MS analysis using 1 M acetic acid as the background electrolyte. This combination of basic elution and acidic background electrolytes results in both sample stacking and formation of a dynamic pH junction. 369 protein groups and 1274 peptides were identified from 50 ng of Xenopus laevis zygote homogenate, which is comparable with an offline sample preparation method, but the time required for sample preparation was decreased from over 24 h to less than 40 min. Dramatically improved performance was produced by coupling the reactor to a longer separation capillary (∼100 cm) and a Q Exactive HF mass spectrometer. 975 protein groups and 3749 peptides were identified from 50 ng of Xenopus protein using the online sample preparation method.

  16. Preparation of Magnetic Hollow Molecularly Imprinted Polymers for Detection of Triazines in Food Samples.

    PubMed

    Wang, Aixiang; Lu, Hongzhi; Xu, Shoufang

    2016-06-22

    Novel magnetic hollow molecularly imprinted polymers (M-H-MIPs) were proposed for highly selective recognition and fast enrichment of triazines in food samples. M-H-MIPs were prepared on the basis of multi-step swelling polymerization, followed by in situ growth of magnetic Fe3O4 nanoparticles on the surface of hollow molecularly imprinted polymers (H-MIPs). Transmission electron microscopy and scanning electron microscopy confirmed the successful immobilization of Fe3O4 nanoparticles on the surface of H-MIPs. M-H-MIPs could be separated simply using an external magnet. The binding adsorption results indicated that M-H-MIPs displayed high binding capacity and fast mass transfer property and class selective property for triazines. Langmuir isotherm and pseudo-second-order kinetic models fitted the best adsorption models for M-H-MIPs. M-H-MIPs were used to analyze atrazine, simazine, propazine, and terbuthylazine in corn, wheat, and soybean samples. Satisfactory recoveries were in the range of 80.62-101.69%, and relative standard deviation was lower than 5.2%. Limits of detection from 0.16 to 0.39 μg L(-1) were obtained. When the method was applied to test positive samples that were contaminated with triazines, the results agree well with those obtained from an accredited method. Thus, the M-H-MIP-based dispersive solid-phase extraction method proved to be a convenient and practical platform for detection of triazines in food samples.

  17. Fluidics platform and method for sample preparation

    DOEpatents

    Benner, Henry W.; Dzenitis, John M.

    2016-06-21

    Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

  18. Nanoparticle-assisted laser desorption/ionization mass spectrometry: Novel sample preparation methods and nanoparticle screening for plant metabolite imaging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yagnik, Gargey B.

    The main goal of the presented research is development of nanoparticle based matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS). This dissertation includes the application of previously developed data acquisition methods, development of novel sample preparation methods, application and comparison of novel nanoparticle matrices, and comparison of two nanoparticle matrix application methods for MALDI-MS and MALDI-MS imaging.

  19. A novel addition polyimide adhesive

    NASA Technical Reports Server (NTRS)

    St.clair, T. L.; Progar, D. J.

    1981-01-01

    An addition polyimide adhesive, LARC 13, was developed which shows promise for bonding both titanium and composites for applications which require service temperatures in excess of 533 K. The LARC 13 is based on an oligomeric bis nadimide containing a meta linked aromatic diamine. The adhesive melts prior to polymerization due to its oligomeric nature, thereby allowing it to be processed at 344 kPa or less. Therefore, LARC 13 is ideal for the bonding of honeycomb sandwich structures. After melting, the resin thermosets during the cure of the nadic endcaps to a highly crosslinked system. Few volatiles are evolved, thus allowing large enclosed structures to be bonded. Preparation of the adhesive as well as bonding, aging, and testing of lap shear and honeycomb samples are discussed.

  20. Preparation of chitosan grafted graphite composite for sensitive detection of dopamine in biological samples.

    PubMed

    Palanisamy, Selvakumar; Thangavelu, Kokulnathan; Chen, Shen-Ming; Gnanaprakasam, P; Velusamy, Vijayalakshmi; Liu, Xiao-Heng

    2016-10-20

    The accurate detection of dopamine (DA) levels in biological samples such as human serum and urine are essential indicators in medical diagnostics. In this work, we describe the preparation of chitosan (CS) biopolymer grafted graphite (GR) composite for the sensitive and lower potential detection of DA in its sub micromolar levels. The composite modified electrode has been used for the detection of DA in biological samples such as human serum and urine. The GR-CS composite modified electrode shows an enhanced oxidation peak current response and low oxidation potential for the detection of DA than that of electrodes modified with bare, GR and CS discretely. Under optimum conditions, the fabricated GR-CS composite modified electrode shows the DPV response of DA in the linear response ranging from 0.03 to 20.06μM. The detection limit and sensitivity of the sensor were estimated as 0.0045μM and 6.06μA μM(-1)cm(-2), respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Performance characterizations of asphalt binders and mixtures incorporating silane additive ZycoTherm

    NASA Astrophysics Data System (ADS)

    Hasan, Mohd Rosli Mohd; Hamzah, Meor Othman; Yee, Teh Sek

    2017-10-01

    Experimental works were conducted to evaluate the properties of asphalt binders and mixtures produced using a relatively new silane additive, named ZycoTherm. In this study, 0.1wt% ZycoTherm was blended with asphalt binder to enable production of asphalt mixture at lower than normal temperatures, as well as improve mix workability and compactability. Asphalt mixture performances towards pavement distresses in tropical climate region were also investigated. The properties of control asphalt binders (60/70 and 80/10 penetration grade) and asphalt binders incorporating 0.1% ZycoTherm were reported based on the penetration, softening point, rotational viscosity, complex modulus and phase angle. Subsequently, to compare the performance of asphalt mixture incorporating ZycoTherm with the control asphalt mixture, cylindrical samples were prepared at recommended temperatures and air voids depending on the binder types and test requirements. The samples were tested for indirect tensile strength (ITS), resilient modulus, dynamic creep, Hamburg wheel tracking and moisture induced damage. From compaction data using the Servopak gyratory compactor, specimen prepared using ZycoTherm exhibit higher workability and compactability compared to the conventional mixture. From the mixture performance test results, mixtures prepared with ZycoTherm showed comparable if not better performance than the control sample in terms of the resistance to moisture damage, permanent deformation and cracking.

  2. Lab-on-a-chip modules for detection of highly pathogenic bacteria: from sample preparation to detection

    NASA Astrophysics Data System (ADS)

    Julich, S.; Kopinč, R.; Hlawatsch, N.; Moche, C.; Lapanje, A.; Gärtner, C.; Tomaso, H.

    2014-05-01

    Lab-on-a-chip systems are innovative tools for the detection and identification of microbial pathogens in human and veterinary medicine. The major advantages are small sample volume and a compact design. Several fluidic modules have been developed to transform analytical procedures into miniaturized scale including sampling, sample preparation, target enrichment, and detection procedures. We present evaluation data for single modules that will be integrated in a chip system for the detection of pathogens. A microfluidic chip for purification of nucleic acids was established for cell lysis using magnetic beads. This assay was evaluated with spiked environmental aerosol and swab samples. Bacillus thuringiensis was used as simulant for Bacillus anthracis, which is closely related but non-pathogenic for humans. Stationary PCR and a flow-through PCR chip module were investigated for specific detection of six highly pathogenic bacteria. The conventional PCR assays could be transferred into miniaturized scale using the same temperature/time profile. We could demonstrate that the microfluidic chip modules are suitable for the respective purposes and are promising tools for the detection of bacterial pathogens. Future developments will focus on the integration of these separate modules to an entire lab-on-a-chip system.

  3. Preparation of core-shell molecularly imprinted polymer via the combination of reversible addition-fragmentation chain transfer polymerization and click reaction.

    PubMed

    Chang, Limin; Li, Ying; Chu, Jia; Qi, Jingyao; Li, Xin

    2010-11-08

    In this paper, we demonstrated an efficient and robust route to the preparation of well-defined molecularly imprinted polymer based on reversible addition-fragmentation chain transfer (RAFT) polymerization and click chemistry. The alkyne terminated RAFT chain transfer agent was first synthesized, and then click reaction was used to graft RAFT agent onto the surface of silica particles which was modified by azide. Finally, imprinted thin film was prepared in the presence of 2,4-dichlorophenol as the template. The imprinted beads were demonstrated with a homogeneous polymer films (thickness of about 2.27 nm), and exhibited thermal stability under 255°C. The as-synthesized product showed obvious molecular imprinting effects towards the template, fast template rebinding kinetics and an appreciable selectivity over structurally related compounds. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Improving FTIR imaging speciation of organic compound residues or their degradation products in wall painting samples, by introducing a new thin section preparation strategy based on cyclododecane pre-treatment.

    PubMed

    Papliaka, Zoi Eirini; Vaccari, Lisa; Zanini, Franco; Sotiropoulou, Sophia

    2015-07-01

    Fourier transform infrared (FTIR) imaging in transmission mode, employing a bidimensional focal plane array (FPA) detector, was applied for the detection and spatially resolved chemical characterisation of organic compounds or their degradation products within the stratigraphy of a critical group of fragments, originating from prehistoric and roman wall paintings, containing a very low concentration of subsisted organic matter or its alteration products. Past analyses using attenuated total reflection (ATR) or reflection FTIR on polished cross sections failed to provide any evidence of any organic material assignable as binding medium of the original painting. In order to improve the method's performance, in the present study, a new method of sample preparation in thin section was developed. The procedure is based on the use of cyclododecane C12H24 as embedding material and a subsequent double-side polishing of the specimen. Such procedure provides samples to be studied in FTIR transmission mode without losing the information on the spatial distribution of the detected materials in the paint stratigraphy. For comparison purposes, the same samples were also studied after opening their stratigraphy with a diamond anvil cell. Both preparation techniques offered high-quality chemical imaging of the decay products of an organic substance, giving clues to the painting technique. In addition, the thin sections resulting from the cyclododecane pre-treatment offered more layer-specific data, as the layer thickness and order remained unaffected, whereas the samples resulting from compression within the diamond cell were slightly deformed; however, since thinner and more homogenous, they provided higher spectral quality in terms of S/N ratio. In summary, the present study illustrates the appropriateness of FTIR imaging in transmission mode associated with a new thin section preparation strategy to detect and localise very low-concentrated organic matter subjected to

  5. Preparation of Protein Samples for NMR Structure, Function, and Small Molecule Screening Studies

    PubMed Central

    Acton, Thomas B.; Xiao, Rong; Anderson, Stephen; Aramini, James; Buchwald, William A.; Ciccosanti, Colleen; Conover, Ken; Everett, John; Hamilton, Keith; Huang, Yuanpeng Janet; Janjua, Haleema; Kornhaber, Gregory; Lau, Jessica; Lee, Dong Yup; Liu, Gaohua; Maglaqui, Melissa; Ma, Lichung; Mao, Lei; Patel, Dayaban; Rossi, Paolo; Sahdev, Seema; Shastry, Ritu; Swapna, G.V.T.; Tang, Yeufeng; Tong, Saichiu; Wang, Dongyan; Wang, Huang; Zhao, Li; Montelione, Gaetano T.

    2014-01-01

    In this chapter, we concentrate on the production of high quality protein samples for NMR studies. In particular, we provide an in-depth description of recent advances in the production of NMR samples and their synergistic use with recent advancements in NMR hardware. We describe the protein production platform of the Northeast Structural Genomics Consortium, and outline our high-throughput strategies for producing high quality protein samples for nuclear magnetic resonance (NMR) studies. Our strategy is based on the cloning, expression and purification of 6X-His-tagged proteins using T7-based Escherichia coli systems and isotope enrichment in minimal media. We describe 96-well ligation-independent cloning and analytical expression systems, parallel preparative scale fermentation, and high-throughput purification protocols. The 6X-His affinity tag allows for a similar two-step purification procedure implemented in a parallel high-throughput fashion that routinely results in purity levels sufficient for NMR studies (> 97% homogeneity). Using this platform, the protein open reading frames of over 17,500 different targeted proteins (or domains) have been cloned as over 28,000 constructs. Nearly 5,000 of these proteins have been purified to homogeneity in tens of milligram quantities (see Summary Statistics, http://nesg.org/statistics.html), resulting in more than 950 new protein structures, including more than 400 NMR structures, deposited in the Protein Data Bank. The Northeast Structural Genomics Consortium pipeline has been effective in producing protein samples of both prokaryotic and eukaryotic origin. Although this paper describes our entire pipeline for producing isotope-enriched protein samples, it focuses on the major updates introduced during the last 5 years (Phase 2 of the National Institute of General Medical Sciences Protein Structure Initiative). Our advanced automated and/or parallel cloning, expression, purification, and biophysical screening

  6. A new comprehensive technique of catheterisation, blood sampling, sample preparation and sample analysis by means of high-pressure liquid chromatography for pharmacokinetic studies with estradiol-linked nitrosoureas and their metabolites.

    PubMed

    Betsch, B; Berger, M R; Spiegelhalder, B

    1990-09-01

    Estradiol-linked nitrosoureas are offering new perspectives in the antineoplastic chemotherapy of estradiol-receptor positive mammary carcinomas. In such a molecule estradiol has the function of a carrier which brings about a specific accumulation of the anticancer drug in estradiol-receptor containing tumor cells. However, there is only little knowledge about the pharmacokinetic behavior of this new group of anticancer agents. For that reason a new comprehensive technique of catheterisation, blood sampling, sample preparation and sample analysis with high-pressure liquid chromatography (HPLC) for preclinical pharmacokinetic studies with estradiol-linked nitrosoureas and their metabolites has been developed. N-(2-Chloroethyl)-N-nitroso-carbamoyl-L-alanine-estradiol-17-ester (CNC-alanine-estradiol-17-ester) and N-(2-chloroethyl)-N-nitroso-carbamoyl-L-alanine (CNC-alanine) were used as test compounds. The drugs were tested in female Sprague-Dawley rats with chemically induced mammary carcinomas. The laboratory animals were supplied with two catheters prior to the pharmacokinetic experiments. The blood samples were drawn from the vena cava catheter after the drug had been applied through a vena jugularis catheter. The compounds were extracted from plasma with C18 silicagel reversed phase cartridges. The clean-up technique delivered clear samples only slightly contaminated with the biological matrix. The recovery from plasma was 75 +/- 5% for the hormone-linked CNC-alanine-estradiol-17-ester and 70 +/- 5% for the unlinked CNC-alanine. The analysis was carried out by means of HPLC.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Protocol for Cohesionless Sample Preparation for Physical Experimentation

    DTIC Science & Technology

    2016-05-01

    protocol for specimen preparation that will enable the use of soil strength curves based on expedient field classification testing (e.g., grain-size...void ratio and relative compaction, which compares field compaction to a laboratory maximum density. Gradation charts for the two materials used in...the failure stress. Ring shear testing was performed using the GCTS Residual-Ring Shear System SRS-150 in order to measure the peak torsional

  8. Spectroscopy applied to feed additives of the European Union Reference Laboratory: a valuable tool for traceability.

    PubMed

    Omar, Jone; Slowikowski, Boleslaw; Boix, Ana; von Holst, Christoph

    2017-08-01

    Feed additives need to be authorised to be placed on the market according to Regulation (EU) No. 1831/2003. Next to laying down the procedural requirements, the regulation creates the European Union Reference Laboratory for Feed Additives (EURL-FA) and requires that applicants send samples to the EURL-FA. Once authorised, the characteristics of the marketed feed additives should correspond to those deposited in the sample bank of the EURL-FA. For this purpose, the submitted samples were subjected to near-infrared (NIR) and Raman spectroscopy for spectral characterisation. These techniques have the valuable potential of characterising the feed additives in a non-destructive manner without any complicated sample preparation. This paper describes the capability of spectroscopy for a rapid characterisation of products to establish whether specific authorisation criteria are met. This study is based on the analysis of feed additive samples from different categories and functional groups, namely products containing (1) selenium, (2) zinc and manganese, (3) vitamins and (4) essential oils such as oregano and thyme oil. The use of chemometrics turned out to be crucial, especially in cases where the differentiation of spectra by visual inspection was very difficult.

  9. Flexible nano- and microliter injections on a single liquid chromatography-mass spectrometry system: Minimizing sample preparation and maximizing linear dynamic range.

    PubMed

    Lubin, Arnaud; Sheng, Sheng; Cabooter, Deirdre; Augustijns, Patrick; Cuyckens, Filip

    2017-11-17

    Lack of knowledge on the expected concentration range or insufficient linear dynamic range of the analytical method applied are common challenges for the analytical scientist. Samples that are above the upper limit of quantification are typically diluted and reanalyzed. The analysis of undiluted highly concentrated samples can cause contamination of the system, while the dilution step is time consuming and as the case for any sample preparation step, also potentially leads to precipitation, adsorption or degradation of the analytes. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Characterization of food additive-potato starch complexes by FTIR and X-ray diffraction.

    PubMed

    Dankar, Iman; Haddarah, Amira; Omar, Fawaz E L; Pujolà, Montserrat; Sepulcre, Francesc

    2018-09-15

    Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques were used to study the effect of four food additives, agar, alginate, lecithin and glycerol, at three different concentrations, 0.5, 1 and 1.5%, on the molecular structure of potato puree prepared from commercial potato powder. Vibrational spectra revealed that the amylose-amylopectin skeleton present in the raw potato starch was missing in the potato powder but could be fully recovered upon water addition when the potato puree was prepared. FTIR peaks corresponding to water were clearly present in the potato powder, indicating the important structural role of water molecules in the recovery of the initial molecular conformation. None of the studied puree samples presented a crystalline structure or strong internal order. A comparison of the FTIR and XRD results revealed that the additives exerted some effects, mainly on the long-range order of the starch structure via interacting with and changing -OH and hydrogen bond interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Acid digestion of geological and environmental samples using open-vessel focused microwave digestion.

    PubMed

    Taylor, Vivien F; Toms, Andrew; Longerich, Henry P

    2002-01-01

    The application of open vessel focused microwave acid digestion is described for the preparation of geological and environmental samples for analysis using inductively coupled plasma-mass spectrometry (ICP-MS). The method is compared to conventional closed-vessel high pressure methods which are limited in the use of HF to break down silicates. Open-vessel acid digestion more conveniently enables the use of HF to remove Si from geological and plant samples as volatile SiF4, as well as evaporation-to-dryness and sequential acid addition during the procedure. Rock reference materials (G-2 granite, MRG-1 gabbros, SY-2 syenite, JA-1 andesite, and JB-2 and SRM-688 basalts) and plant reference materials (BCR and IAEA lichens, peach leaves, apple leaves, Durham wheat flour, and pine needles) were digested with results comparable to conventional hotplate digestion. The microwave digestion method gave poor results for granitic samples containing refractory minerals, however fusion was the preferred method of preparation for these samples. Sample preparation time was reduced from several days, using conventional hotplate digestion method, to one hour per sample using our microwave method.

  12. Isolation of naturally infecting Leishmania infantum from canine samples in Novy-MacNeal-Nicolle medium prepared with defibrinated blood from different animal species.

    PubMed

    Santos, Roseclea Chagas Dos; Pinho, Flaviane Alves de; Passos, Gabriela Porfírio; Larangeira, Daniela Farias; Barrouin-Melo, Stella Maria

    2018-06-15

    The most commonly used culture medium for the in vitro isolation of Leishmania spp. from canine biological samples is biphasic Novy-MacNeal-Nicolle (NNN) medium, whose solid phase is prepared using rabbit blood. Leishmania infantum parasites from natural infections are highly sensitive and demanding for growth in axenic conditions when firstly obtained from the dog's body. The objective of this study was to evaluate whether NNN medium (NNN-test) prepared with chicken blood (NNN-C), ox blood (NNN-O), horse blood (NNN-H) or sheep blood (NNN-S) was viable for the isolation of parasites from naturally infected dogs, in an endemic area for visceral leishmaniasis caused by L. infantum. Spleen aspirates from six dogs previously diagnosed as infected by parasitological methods were simultaneously inoculated in each NNN-test medium, including the conventional medium prepared with rabbit blood (NNN-R), and the cultures were examined for three weeks under optic microscopy. Spleen samples were also analyzed for parasite loads by quantitative PCR (qPCR). Cultures from three of the six dogs (50%) were positive in at least one of the NNN-test media: one sample presented the highest spleen parasite load by qPCR (1.19 × 10 4 parasites/mL) and was positive in all test media; the second sample presented parasitic isolation in the first week of culture in all inoculated media, of which the NNN-C medium had the highest mean parasite count (NNN-C = 23.5 × 10 4 /mL vs. NNN-R = 3.25 × 10 4 /mL); the third sample was positive only in the NNN-S medium besides the conventional control NNN-R. Cultures from the three remaining dogs were negative in all NNN media, including the control and test media; of those three dogs, two presented the lowest spleen parasitic loads according to qPCR. Blood from chicken, ox, horse and sheep shown to be viable for the preparation of NNN culture medium for the primary isolation of L. infantum from samples of naturally infected dogs and

  13. The effect of different levels of sunflower head pith addition on the properties of model system emulsions prepared from fresh and frozen beef.

    PubMed

    Sariçoban, Cemalettin; Yilmaz, Mustafa Tahsin; Karakaya, Mustafa; Tiske, Sümeyra Sultan

    2010-01-01

    The effect of sunflower head pith on the functional properties of emulsions was studied by using a model system. Oil/water (O/W) model emulsion systems were prepared from fresh and frozen beef by the addition of the pith at five concentrations. Emulsion capacity (EC), stability (ES), viscosity (EV), colour and flow properties of the prepared model system emulsions were analyzed. The pith addition increased the EC and ES and the highest EC and ES values were reached when 5% of pith added; however, further increase in the pith concentration caused an inverse trend in these values. Fresh beef emulsions had higher EC and ES values than did frozen beef emulsions. One percent pith concentration was the critic level for the EV values of fresh beef emulsions. EV values of the emulsions reached a maximum level at 5% pith level, followed by a decrease at 7% pit level.

  14. Rapid Automated Sample Preparation for Biological Assays

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shusteff, M

    Our technology utilizes acoustic, thermal, and electric fields to separate out contaminants such as debris or pollen from environmental samples, lyse open cells, and extract the DNA from the lysate. The objective of the project is to optimize the system described for a forensic sample, and demonstrate its performance for integration with downstream assay platforms (e.g. MIT-LL's ANDE). We intend to increase the quantity of DNA recovered from the sample beyond the current {approx}80% achieved using solid phase extraction methods. Task 1: Develop and test an acoustic filter for cell extraction. Task 2: Develop and test lysis chip. Task 3:more » Develop and test DNA extraction chip. All chips have been fabricated based on the designs laid out in last month's report.« less

  15. Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

    NASA Astrophysics Data System (ADS)

    Yokochi, Reika

    2016-09-01

    Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

  16. Rapid production of hollow SS316 profiles by extrusion based additive manufacturing

    NASA Astrophysics Data System (ADS)

    Rane, Kedarnath; Cataldo, Salvatore; Parenti, Paolo; Sbaglia, Luca; Mussi, Valerio; Annoni, Massimiliano; Giberti, Hermes; Strano, Matteo

    2018-05-01

    Complex shaped stainless steel tubes are often required for special purpose biomedical equipment. Nevertheless, traditional manufacturing technologies, such as extrusion, lack the ability to compete in a market of customized complex components because of associated expenses towards tooling and extrusion presses. To rapid manufacture few of such components with low cost and high precision, a new Extrusion based Additive Manufacturing (EAM) process, is proposed in this paper, and as an example, short stainless steel 316L complex shaped and sectioned tubes were prepared by EAM. Several sample parts were produced using this process; the dimensional stability, surface roughness and chemical composition of sintered samples were investigated to prove process competence. The results indicate that feedstock with a 316L particle content of 92.5 wt. % can be prepared with a sigma blade mixing, whose rheological behavior is fit for EAM. The green samples have sufficient strength to handle them for subsequent treatments. The sintered samples considerably shrunk to designed dimensions and have a homogeneous microstructure to impart mechanical strength. Whereas, maintaining comparable dimensional accuracy and chemical composition which are required for biomedical equipment still need iterations, a kinematic correction and modification in debinding cycle was proposed.

  17. A flexible method for the preparation of thin film samples for in situ TEM characterization combining shadow-FIB milling and electron-beam-assisted etching.

    PubMed

    Liebig, J P; Göken, M; Richter, G; Mačković, M; Przybilla, T; Spiecker, E; Pierron, O N; Merle, B

    2016-12-01

    A new method for the preparation of freestanding thin film samples for mechanical testing in transmission electron microscopes is presented. It is based on a combination of focused ion beam (FIB) milling and electron-beam-assisted etching with xenon difluoride (XeF 2 ) precursor gas. The use of the FIB allows for the target preparation of microstructural defects and enables well-defined sample geometries which can be easily adapted in order to meet the requirements of various testing setups. In contrast to existing FIB-based preparation approaches, the area of interest is never exposed to ion beam irradiation which preserves a pristine microstructure. The method can be applied to a wide range of thin film material systems compatible with XeF 2 etching. Its feasibility is demonstrated for gold and alloyed copper thin films and its practical application is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. 40 CFR 1065.1107 - Sample media and sample system preparation; sample system assembly.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) For capturing PM, we recommend using pure quartz filters with no binder. Select the filter diameter to minimize filter change intervals, accounting for the expected PM emission rate, sample flow rate, and... filter without replacing the sorbent or otherwise disassembling the batch sampler. In those cases...

  19. Drilling mud additives

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roemer, P.; Downhour, R. Jr.

    1970-06-30

    A drilling mud additive prepared from farinaceous material contains relatively high gluten and fat contents and has between 30 and 40% water soluble solids on a dry basis. The product is particularly useful in rotary drilling as an additive to the drilling mud to inhibit water loss. The key to achieving the desired product is pretreatment of the raw flour and control of moisture. (2 claims)

  20. 7 CFR 27.89 - Expenses; inspection; sampling.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Expenses; inspection; sampling. 27.89 Section 27.89... Micronaire § 27.89 Expenses; inspection; sampling. Expense of inspection and sampling, the preparation of the... Office, the expense of inspection, sampling, preparation of samples, and delivery of the samples to the...

  1. 7 CFR 27.89 - Expenses; inspection; sampling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Expenses; inspection; sampling. 27.89 Section 27.89... Micronaire § 27.89 Expenses; inspection; sampling. Expense of inspection and sampling, the preparation of the... Office, the expense of inspection, sampling, preparation of samples, and delivery of the samples to the...

  2. Evaluation of three sample preparation methods for the direct identification of bacteria in positive blood cultures by MALDI-TOF.

    PubMed

    Tanner, Hannah; Evans, Jason T; Gossain, Savita; Hussain, Abid

    2017-01-18

    Patient mortality is significantly reduced by rapid identification of bacteria from sterile sites. MALDI-TOF can identify bacteria directly from positive blood cultures and multiple sample preparation methods are available. We evaluated three sample preparation methods and two MALDI-TOF score cut-off values. Positive blood culture bottles with organisms present in Gram stains were prospectively analysed by MALDI-TOF. Three lysis reagents (Saponin, SDS, and SepsiTyper lysis bufer) were applied to each positive culture followed by centrifugation, washing and protein extraction steps. Methods were compared using the McNemar test and 16S rDNA sequencing was used to assess discordant results. In 144 monomicrobial cultures, using ≥2.000 as the cut-off value, species level identifications were obtained from 69/144 (48%) samples using Saponin, 86/144 (60%) using SDS, and 91/144 (63%) using SepsiTyper. The difference between SDS and SepsiTyper was not statistically significant (P = 0.228). Differences between Saponin and the other two reagents were significant (P < 0.01). Using ≥1.700 plus top three results matching as the cut-off value, species level identifications were obtained from 100/144 (69%) samples using Saponin, 103/144 (72%) using SDS, and 106/144 (74%) using SepsiTyper and there was no statistical difference between the methods. No true discordances between culture and direct MALDI-TOF identification were observed in monomicrobial cultures. In 32 polymicrobial cultures, MALDI-TOF identified one organism in 34-75% of samples depending on the method. This study demonstrates two inexpensive in-house detergent lysis methods are non-inferior to a commercial kit for analysis of positive blood cultures by direct MALDI-TOF in a clinical diagnostic microbiology laboratory.

  3. Magnetic particles for in vitro molecular diagnosis: From sample preparation to integration into microsystems.

    PubMed

    Tangchaikeeree, Tienrat; Polpanich, Duangporn; Elaissari, Abdelhamid; Jangpatarapongsa, Kulachart

    2017-10-01

    Colloidal magnetic particles (MPs) have been developed in association with molecular diagnosis for several decades. MPs have the great advantage of easy manipulation using a magnet. In nucleic acid detection, these particles can act as a capture support for rapid and simple biomolecule separation. The surfaces of MPs can be modified by coating with various polymer materials to provide functionalization for different applications. The use of MPs enhances the sensitivity and specificity of detection due to the specific activity on the surface of the particles. Practical applications of MPs demonstrate greater efficiency than conventional methods. Beyond traditional detection, MPs have been successfully adopted as a smart carrier in microfluidic and lab-on-a-chip biosensors. The versatility of MPs has enabled their integration into small single detection units. MPs-based biosensors can facilitate rapid and highly sensitive detection of very small amounts of a sample. In this review, the application of MPs to the detection of nucleic acids, from sample preparation to analytical readout systems, is described. State-of-the-art integrated microsystems containing microfluidic and lab-on-a-chip biosensors for the nucleic acid detection are also addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Critical evaluation of sample pretreatment techniques.

    PubMed

    Hyötyläinen, Tuulia

    2009-06-01

    Sample preparation before chromatographic separation is the most time-consuming and error-prone part of the analytical procedure. Therefore, selecting and optimizing an appropriate sample preparation scheme is a key factor in the final success of the analysis, and the judicious choice of an appropriate procedure greatly influences the reliability and accuracy of a given analysis. The main objective of this review is to critically evaluate the applicability, disadvantages, and advantages of various sample preparation techniques. Particular emphasis is placed on extraction techniques suitable for both liquid and solid samples.

  5. Hair analysis for cocaine: factors in laboratory contamination studies and their relevance to proficiency sample preparation and hair testing practices.

    PubMed

    Hill, Virginia; Cairns, Thomas; Schaffer, Michael

    2008-03-21

    Hair samples were contaminated by rubbing with cocaine (COC) followed by sweat application, multiple shampoo treatments and storage. The samples were then washed with isopropanol for 15min, followed by sequential aqueous washes totaling 3.5h. The amount of drug in the last wash was used to calculate a wash criterion to determine whether samples were positive due to use or contamination. Analyses of cocaine and metabolites were done by LC/MS/MS. These procedures were applied to samples produced by a U.S. government-sponsored cooperative study, in which this laboratory participated, and to samples in a parallel in-house study. All contaminated samples in both studies were correctly identified as contaminated by cutoff, benzoylecgonine (BE) presence, BE ratio, and/or the wash criterion. A method for determining hair porosity was applied to samples in both studies, and porosity characteristics of hair are discussed as they relate to experimental and real-world contamination of hair, preparation of proficiency survey samples, and analysis of unknown hair samples.

  6. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING URINE SAMPLES FOR ANALYSIS OF HYDROXY POLYCYCLIC AROMATIC HYDROCARBONS, PENTACHLOROPHENOL AND 2,4-D (SOP-5.21)

    EPA Science Inventory

    The method for extracting and preparing urine samples for analysis of hydroxy-polycyclic aromatic hydrocarbons, pentachlorophenol and 2,4-D is summarized in this SOP. It covers the extraction, concentration and methylation of samples that are to be analyzed by gas chromatography/...

  7. Use of CTX-I and PINP as bone turnover markers: National Bone Health Alliance recommendations to standardize sample handling and patient preparation to reduce pre-analytical variability.

    PubMed

    Szulc, P; Naylor, K; Hoyle, N R; Eastell, R; Leary, E T

    2017-09-01

    The National Bone Health Alliance (NBHA) recommends standardized sample handling and patient preparation for C-terminal telopeptide of type I collagen (CTX-I) and N-terminal propeptide of type I procollagen (PINP) measurements to reduce pre-analytical variability. Controllable and uncontrollable patient-related factors are reviewed to facilitate interpretation and minimize pre-analytical variability. The IOF and the International Federation of Clinical Chemistry (IFCC) Bone Marker Standards Working Group have identified PINP and CTX-I in blood to be the reference markers of bone turnover for the fracture risk prediction and monitoring of osteoporosis treatment. Although used in clinical research for many years, bone turnover markers (BTM) have not been widely adopted in clinical practice primarily due to their poor within-subject and between-lab reproducibility. The NBHA Bone Turnover Marker Project team aim to reduce pre-analytical variability of CTX-I and PINP measurements through standardized sample handling and patient preparation. Recommendations for sample handling and patient preparations were made based on review of available publications and pragmatic considerations to reduce pre-analytical variability. Controllable and un-controllable patient-related factors were reviewed to facilitate interpretation and sample collection. Samples for CTX-I must be collected consistently in the morning hours in the fasted state. EDTA plasma is preferred for CTX-I for its greater sample stability. Sample collection conditions for PINP are less critical as PINP has minimal circadian variability and is not affected by food intake. Sample stability limits should be observed. The uncontrollable aspects (age, sex, pregnancy, immobility, recent fracture, co-morbidities, anti-osteoporotic drugs, other medications) should be considered in BTM interpretation. Adopting standardized sample handling and patient preparation procedures will significantly reduce controllable pre

  8. Hydroxyapatite with Permanent Electrical Polarization: Preparation, Characterization, and Response against Inorganic Adsorbates.

    PubMed

    Rivas, Manuel; Del Valle, Luis J; Armelin, Elaine; Bertran, Oscar; Turon, Pau; Puiggalí, Jordi; Alemán, Carlos

    2018-04-16

    Permanently polarized hydroxyapatite (HAp) particles have been prepared by applying a constant DC of 500 V at 1000 °C for 1 h to the sintered mineral. This process causes important chemical changes, as the formation of OH - defects (vacancies), the disappearance of hydrogenophosphate ions at the mineral surface layer, and structural variations reflected by the increment of the crystallinity. As a consequence, the electrochemical properties and electrical conductivity of the polarized mineral increase noticeably compared with as-prepared and sintered samples. Moreover, these increments remain practically unaltered after several months. In addition, permanent polarization favours significantly the ability of HAp to adsorb inorganic bioadsorbates in comparison with as-prepared and sintered samples. The adsorbates cause a significant increment of the electrochemical stability and electrical conductivity with respect to bare polarized HAp, which may have many implications for biomedical applications of permanently polarized HAp. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. [Developments in preparation and experimental method of solid phase microextraction fibers].

    PubMed

    Yi, Xu; Fu, Yujie

    2004-09-01

    Solid phase microextraction (SPME) is a simple and effective adsorption and desorption technique, which concentrates volatile or nonvolatile compounds from liquid samples or headspace of samples. SPME is compatible with analyte separation and detection by gas chromatography, high performance liquid chromatography, and other instrumental methods. It can provide many advantages, such as wide linear scale, low solvent and sample consumption, short analytical times, low detection limits, simple apparatus, and so on. The theory of SPME is introduced, which includes equilibrium theory and non-equilibrium theory. The novel development of fiber preparation methods and relative experimental techniques are discussed. In addition to commercial fiber preparation, different newly developed fabrication techniques, such as sol-gel, electronic deposition, carbon-base adsorption, high-temperature epoxy immobilization, are presented. Effects of extraction modes, selection of fiber coating, optimization of operating conditions, method sensitivity and precision, and systematical automation, are taken into considerations in the analytical process of SPME. A simple perspective of SPME is proposed at last.

  10. Using solvent-free sample preparation to promote protonation of poly(ethylene oxide)s with labile end-groups in matrix-assisted laser desorption/ionisation.

    PubMed

    Mazarin, Michael; Phan, Trang N T; Charles, Laurence

    2008-12-01

    Protonation is usually required to observe intact ions during matrix-assisted laser desorption/ionization (MALDI) of polymers containing fragile end-groups while cation adduction induces chain-end degradation. These polymers, generally obtained via living free radical polymerization techniques, are terminated with a functionality in which a bond is prone to homolytic cleavage, as required by the polymerization process. A solvent-free sample preparation method was used here to avoid salt contaminant from the solvent traditionally used in the dried-droplet MALDI procedure. Solvent-based and solvent-free sample preparations were compared for a series of three poly(ethylene oxide) polymers functionalized with a labile end-group in a nitroxide-mediated polymerization reaction, using 2,4,6-trihydroxyacetophenone (THAP) as the matrix without any added salt. Intact oligomer ions could only be produced as protonated molecules in solvent-free MALDI while sodium adducts of degraded polymers were formed from the dried-droplet samples. Although MALDI analysis was performed at the laser threshold, fragmentation of protonated macromolecules was still observed to occur. However, in contrast to sodiated molecules, dissociation of protonated oligomers does not involve the labile C--ON bond of the end-group. As the macromolecule size increased, protonation appeared to be less efficient and sodium adduction became the dominant ionization process, although no sodium salt was added in the preparation. Formation of sodiated degraded macromolecules would be dictated by increasing cation affinity as the size of the oligomers increases and would reveal the presence of salts at trace levels in the MALDI samples.

  11. Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

    PubMed Central

    Feist, Peter; Hummon, Amanda B.

    2015-01-01

    Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed. PMID:25664860

  12. Liquid-Based Medium Used to Prepare Cytological Breast Nipple Fluid Improves the Quality of Cellular Samples Automatic Collection

    PubMed Central

    Zonta, Marco Antonio; Velame, Fernanda; Gema, Samara; Filassi, Jose Roberto; Longatto-Filho, Adhemar

    2014-01-01

    Background Breast cancer is the second cause of death in women worldwide. The spontaneous breast nipple discharge may contain cells that can be analyzed for malignancy. Halo® Mamo Cyto Test (HMCT) was recently developed as an automated system indicated to aspirate cells from the breast ducts. The objective of this study was to standardize the methodology of sampling and sample preparation of nipple discharge obtained by the automated method Halo breast test and perform cytological evaluation in samples preserved in liquid medium (SurePath™). Methods We analyzed 564 nipple fluid samples, from women between 20 and 85 years old, without history of breast disease and neoplasia, no pregnancy, and without gynecologic medical history, collected by HMCT method and preserved in two different vials with solutions for transport. Results From 306 nipple fluid samples from method 1, 199 (65%) were classified as unsatisfactory (class 0), 104 (34%) samples were classified as benign findings (class II), and three (1%) were classified as undetermined to neoplastic cells (class III). From 258 samples analyzed in method 2, 127 (49%) were classified as class 0, 124 (48%) were classified as class II, and seven (2%) were classified as class III. Conclusion Our study suggests an improvement in the quality and quantity of cellular samples when the association of the two methodologies is performed, Halo breast test and the method in liquid medium. PMID:29147397

  13. Improvement of a sample preparation procedure for multi-elemental determination in Brazil nuts by ICP-OES.

    PubMed

    Welna, Maja; Szymczycha-Madeja, Anna

    2014-04-01

    Various sample preparation procedures, such as common wet digestions and alternatives based on solubilisation in aqua regia or tetramethyl ammonium hydroxide, were compared for the determination of the total Ba, Ca, Cr, Cd, Cu, Fe, Mg, Mn, Ni, P, Pb, Se, Sr and Zn contents in Brazil nuts using inductively coupled plasma optical emission spectrometry (ICP-OES). For measurement of Se, a hydride generation technique was used. The performance of these procedures was measured in terms of precision, accuracy and limits of detection of the elements. It was found that solubilisation in aqua regia gave the best results, i.e. limits of detection from 0.60 to 41.9 ng ml(-1), precision of 1.0-3.9% and accuracy better than 5%. External calibration with simple standard solutions could be applied for the analysis. The proposed procedure is simple, reduces sample handling, and minimises the time and reagent consumption. Thus, this can be a vital alternative to traditional sample treatment approaches based on the total digestion with concentrated reagents. A phenomenon resulting from levels of Ba, Se and Sr in Brazil nuts was also discussed.

  14. Falcon: Visual analysis of large, irregularly sampled, and multivariate time series data in additive manufacturing

    DOE PAGES

    Steed, Chad A.; Halsey, William; Dehoff, Ryan; ...

    2017-02-16

    Flexible visual analysis of long, high-resolution, and irregularly sampled time series data from multiple sensor streams is a challenge in several domains. In the field of additive manufacturing, this capability is critical for realizing the full potential of large-scale 3D printers. Here, we propose a visual analytics approach that helps additive manufacturing researchers acquire a deep understanding of patterns in log and imagery data collected by 3D printers. Our specific goals include discovering patterns related to defects and system performance issues, optimizing build configurations to avoid defects, and increasing production efficiency. We introduce Falcon, a new visual analytics system thatmore » allows users to interactively explore large, time-oriented data sets from multiple linked perspectives. Falcon provides overviews, detailed views, and unique segmented time series visualizations, all with adjustable scale options. To illustrate the effectiveness of Falcon at providing thorough and efficient knowledge discovery, we present a practical case study involving experts in additive manufacturing and data from a large-scale 3D printer. The techniques described are applicable to the analysis of any quantitative time series, though the focus of this paper is on additive manufacturing.« less

  15. Falcon: Visual analysis of large, irregularly sampled, and multivariate time series data in additive manufacturing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steed, Chad A.; Halsey, William; Dehoff, Ryan

    Flexible visual analysis of long, high-resolution, and irregularly sampled time series data from multiple sensor streams is a challenge in several domains. In the field of additive manufacturing, this capability is critical for realizing the full potential of large-scale 3D printers. Here, we propose a visual analytics approach that helps additive manufacturing researchers acquire a deep understanding of patterns in log and imagery data collected by 3D printers. Our specific goals include discovering patterns related to defects and system performance issues, optimizing build configurations to avoid defects, and increasing production efficiency. We introduce Falcon, a new visual analytics system thatmore » allows users to interactively explore large, time-oriented data sets from multiple linked perspectives. Falcon provides overviews, detailed views, and unique segmented time series visualizations, all with adjustable scale options. To illustrate the effectiveness of Falcon at providing thorough and efficient knowledge discovery, we present a practical case study involving experts in additive manufacturing and data from a large-scale 3D printer. The techniques described are applicable to the analysis of any quantitative time series, though the focus of this paper is on additive manufacturing.« less

  16. Overcoming Matrix Effects in a Complex Sample: Analysis of Multiple Elements in Multivitamins by Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Arnold, Randy J.; Arndt, Brett; Blaser, Emilia; Blosser, Chris; Caulton, Dana; Chung, Won Sog; Fiorenza, Garrett; Heath, Wyatt; Jacobs, Alex; Kahng, Eunice; Koh, Eun; Le, Thao; Mandla, Kyle; McCory, Chelsey; Newman, Laura; Pithadia, Amit; Reckelhoff, Anna; Rheinhardt, Joseph; Skljarevski, Sonja; Stuart, Jordyn; Taylor, Cassie; Thomas, Scott; Tse, Kyle; Wall, Rachel; Warkentien, Chad

    2011-01-01

    A multivitamin tablet and liquid are analyzed for the elements calcium, magnesium, iron, zinc, copper, and manganese using atomic absorption spectrometry. Linear calibration and standard addition are used for all elements except calcium, allowing for an estimate of the matrix effects encountered for this complex sample. Sample preparation using…

  17. Evolution of the magnetic properties of Co10Cu90 nanoparticles prepared by wet chemistry with thermal annealing.

    PubMed

    García, I; Echeberria, J; Kakazei, G N; Golub, V O; Saliuk, O Y; Ilyn, M; Guslienko, K Y; González, J M

    2012-09-01

    Nanoparticles of Co10Cu90 alloy have been prepared by sonochemical wet method. According to transmission electron microscopy, bimetallic particles with typical diameter of 50-100 nm consisting of nanocrystallites with average diameter of 15-20 nm were obtained. The samples were annealed at 300 degrees C and 450 degrees C. Zero field cooled and field cooled temperature dependences of magnetization in the temperature range of 5-400 K at 50 Oe, as well as magnetization hysteresis loops at 15, 100 and 305 K were measured by vibrating sample magnetometry. Presence of antiferromagnetic phase, most probably of the oxide Co3O4, was observed in as-prepared sample. The lowest coercivity was found for the CoCu sample annealed at-300 degrees C, whereas for as prepared sample and the one annealed at 450 degrees C it was significantly higher. The samples were additionally probed by continuous wave ferromagnetic resonance at room, temperature using a standard X-band electron spin resonance spectrometer. A good correspondence between evolution of the coercivity and the microwave resonance fields with annealing temperature was observed.

  18. Comparison of sample preparation techniques and data analysis for the LC-MS/MS-based identification of proteins in human follicular fluid.

    PubMed

    Lehmann, Roland; Schmidt, André; Pastuschek, Jana; Müller, Mario M; Fritzsche, Andreas; Dieterle, Stefan; Greb, Robert R; Markert, Udo R; Slevogt, Hortense

    2018-06-25

    The proteomic analysis of complex body fluids by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis requires the selection of suitable sample preparation techniques and optimal parameter settings in data analysis software packages to obtain reliable results. Proteomic analysis of follicular fluid, as a representative of a complex body fluid similar to serum or plasma, is difficult as it contains a vast amount of high abundant proteins and a variety of proteins with different concentrations. However, the accessibility of this complex body fluid for LC-MS/MS analysis is an opportunity to gain insights into the status, the composition of fertility-relevant proteins including immunological factors or for the discovery of new diagnostic and prognostic markers for, for example, the treatment of infertility. In this study, we compared different sample preparation methods (FASP, eFASP and in-solution digestion) and three different data analysis software packages (Proteome Discoverer with SEQUEST, Mascot and MaxQuant with Andromeda) combined with semi- and full-tryptic databank search options to obtain a maximum coverage of the follicular fluid proteome. We found that the most comprehensive proteome coverage is achieved by the eFASP sample preparation method using SDS in the initial denaturing step and the SEQUEST-based semi-tryptic data analysis. In conclusion, we have developed a fractionation-free methodical workflow for in depth LC-MS/MS-based analysis for the standardized investigation of human follicle fluid as an important representative of a complex body fluid. Taken together, we were able to identify a total of 1392 proteins in follicular fluid. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Novel, improved sample preparation for rapid, direct identification from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.

    PubMed

    Schubert, Sören; Weinert, Kirsten; Wagner, Chris; Gunzl, Beatrix; Wieser, Andreas; Maier, Thomas; Kostrzewa, Markus

    2011-11-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used for rapid and reliable identification of bacteria and yeast grown on agar plates. Moreover, MALDI-TOF MS also holds promise for bacterial identification from blood culture (BC) broths in hospital laboratories. The most important technical step for the identification of bacteria from positive BCs by MALDI-TOF MS is sample preparation to remove blood cells and host proteins. We present a method for novel, rapid sample preparation using differential lysis of blood cells. We demonstrate the efficacy and ease of use of this sample preparation and subsequent MALDI-TOF MS identification, applying it to a total of 500 aerobic and anaerobic BCs reported to be positive by a Bactec 9240 system. In 86.5% of all BCs, the microorganism species were correctly identified. Moreover, in 18/27 mixed cultures at least one isolate was correctly identified. A novel method that adjusts the score value for MALDI-TOF MS results is proposed, further improving the proportion of correctly identified samples. The results of the present study show that the MALDI-TOF MS-based method allows rapid (<20 minutes) bacterial identification directly from positive BCs and with high accuracy. Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  20. Distributed fiber sparse-wideband vibration sensing by sub-Nyquist additive random sampling

    NASA Astrophysics Data System (ADS)

    Zhang, Jingdong; Zheng, Hua; Zhu, Tao; Yin, Guolu; Liu, Min; Bai, Yongzhong; Qu, Dingrong; Qiu, Feng; Huang, Xianbing

    2018-05-01

    The round trip time of the light pulse limits the maximum detectable vibration frequency response range of phase-sensitive optical time domain reflectometry ({\\phi}-OTDR). Unlike the uniform laser pulse interval in conventional {\\phi}-OTDR, we randomly modulate the pulse interval, so that an equivalent sub-Nyquist additive random sampling (sNARS) is realized for every sensing point of the long interrogation fiber. For an {\\phi}-OTDR system with 10 km sensing length, the sNARS method is optimized by theoretical analysis and Monte Carlo simulation, and the experimental results verify that a wide-band spars signal can be identified and reconstructed. Such a method can broaden the vibration frequency response range of {\\phi}-OTDR, which is of great significance in sparse-wideband-frequency vibration signal detection, such as rail track monitoring and metal defect detection.

  1. Carprofen-imprinted monolith prepared by reversible addition-fragmentation chain transfer polymerization in room temperature ionic liquids.

    PubMed

    Ban, Lu; Han, Xu; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

    2013-10-01

    To obtain fast separation, ionic liquids were used as porogens first in combination with reversible addition-fragmentation chain transfer (RAFT) polymerization to prepare a new type of molecularly imprinted polymer (MIP) monolith. The imprinted monolithic column was synthesized using a mixture of carprofen (template), 4-vinylpyridine, ethylene glycol dimethacrylate, [BMIM]BF4, and chain transfer agent (CTA). Some polymerization factors, such as template-monomer molar ratio, the degree of crosslinking, the composition of the porogen, and the content of CTA, on the column efficiency and imprinting effect of the resulting MIP monolith were systematically investigated. Affinity screening of structurally similar compounds with the template can be achieved in 200 s on the MIP monolith due to high column efficiency (up to 12,070 plates/m) and good column permeability. Recognition mechanism of the imprinted monolith was also investigated.

  2. Curation of Frozen Samples

    NASA Technical Reports Server (NTRS)

    Fletcher, L. A.; Allen, C. C.; Bastien, R.

    2008-01-01

    NASA's Johnson Space Center (JSC) and the Astromaterials Curator are charged by NPD 7100.10D with the curation of all of NASA s extraterrestrial samples, including those from future missions. This responsibility includes the development of new sample handling and preparation techniques; therefore, the Astromaterials Curator must begin developing procedures to preserve, prepare and ship samples at sub-freezing temperatures in order to enable future sample return missions. Such missions might include the return of future frozen samples from permanently-shadowed lunar craters, the nuclei of comets, the surface of Mars, etc. We are demonstrating the ability to curate samples under cold conditions by designing, installing and testing a cold curation glovebox. This glovebox will allow us to store, document, manipulate and subdivide frozen samples while quantifying and minimizing contamination throughout the curation process.

  3. Bioactive composition and antioxidant potential of different commonly consumed coffee brews affected by their preparation technique and milk addition.

    PubMed

    Niseteo, Tena; Komes, Draženka; Belščak-Cvitanović, Ana; Horžić, Dunja; Budeč, Maja

    2012-10-15

    Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of total phenols and flavonoids was determined spectrophotometrically and the content of chlorogenic acid derivates (3-CQA, 4-CQA and 5-CQA) and caffeine using the high performance liquid chromatography (HPLC-PDA). Antioxidant capacity of coffee brews was evaluated by using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) and FRAP (ferric-reducing antioxidant power) assays. Instant coffee brews showed the highest values in content of total phenols, chlorogenic acid derivates, caffeine and antioxidant capacity, which significantly decreased by milk addition. The antioxidant capacity of coffee brews was in compliance with the total phenol content and content of chlorogenic acid derivates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Comparative study of the molecularly imprinted polymers prepared by reversible addition-fragmentation chain transfer "bulk" polymerization and traditional radical "bulk" polymerization.

    PubMed

    Ma, Yue; Pan, Guoqing; Zhang, Ying; Guo, Xianzhi; Zhang, Huiqi

    2013-05-01

    Bisphenol A (BPA) and propranolol-imprinted polymers have been prepared via both reversible addition-fragmentation chain transfer "bulk" polymerization (RAFTBP) and traditional radical "bulk" polymerization (TRBP) under similar reaction conditions, and their equilibrium binding properties were compared in detail for the first time. The chemical compositions, specific surface areas, equilibrium bindings, and selectivity of the obtained molecularly imprinted polymers (MIPs) were systematically characterized. The experimental results showed that the MIPs with molecular imprinting effects and quite fast binding kinetics could be readily prepared via RAFTBP, but they did not show improved template binding properties in comparison with those prepared via TRBP, which is in sharp contrast to many previous reports. This could be attributed to the heavily interrupted equilibrium between the dormant species and active radicals in the RAFT mechanism because of the occurrence of fast gelation during RAFTBP. The findings presented here strongly demonstrates that the application of controlled radical polymerizations (CRPs) in molecular imprinting does not always benefit the binding properties of the resultant MIPs, which is of significant importance for the rational use of CRPs in generating MIPs with improved properties. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Machine for Automatic Bacteriological Pour Plate Preparation

    PubMed Central

    Sharpe, A. N.; Biggs, D. R.; Oliver, R. J.

    1972-01-01

    A fully automatic system for preparing poured plates for bacteriological analyses has been constructed and tested. The machine can make decimal dilutions of bacterial suspensions, dispense measured amounts into petri dishes, add molten agar, mix the dish contents, and label the dishes with sample and dilution numbers at the rate of 2,000 dishes per 8-hr day. In addition, the machine can be programmed to select different media so that plates for different types of bacteriological analysis may be made automatically from the same sample. The machine uses only the components of the media and sterile polystyrene petri dishes; requirements for all other materials, such as sterile pipettes and capped bottles of diluents and agar, are eliminated. Images PMID:4560475

  6. SPME-GC-pyrolysis-AFS determination of methylmercury in marine fish products by alkaline sample preparation and aqueous phase phenylation derivatization.

    PubMed

    Jókai, Zsuzsa; Abrankó, László; Fodor, Péter

    2005-07-13

    Characterization of a cost-efficient analytical method based on alkaline sample digestion with KOH and NaOH, followed by aqueous phase phenylation derivatization with NaBPh4 and solid phase microextraction (SPME) for the determination of methylmercury in typical fish-containing food samples commercially available in Hungary, is reported. The sample preparation procedure along with the applied SPME-GC-pyrolysis-AFS system was validated by measuring certified reference materials (CRM) BCR-464, TORT-2, and a candidate CRM BCR 710. To carry out an estimation of average Hungarian methylmercury exposures via marine fish and/or fish-containing food consumption, 16 commercially available products and 3 pooled representative seafood samples of-according to a previous European survey--the three most consumed fish species in Hungary, herring, sardines, and hake, were analyzed. Methylmercury concentrations of the analyzed samples were in the range 0.016-0.137 microg of MeHg g(-1) dry weight as Hg.

  7. A green analytical method using ultrasound in sample preparation for the flow injection determination of iron, manganese, and zinc in soluble solid samples by flame atomic absorption spectrometry.

    PubMed

    Yebra, M Carmen

    2012-01-01

    A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5-30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2-4.6%) and a sample throughput of ca. 25 samples h(-1) were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4-25.61 μg g(-1) for iron, 5.74-18.30 μg g(-1) for manganese, and 33.27-57.90 μg g(-1) for zinc in soluble solid food samples and 3.75-9.90 μg g(-1) for iron, 0.47-5.05 μg g(-1) for manganese, and 1.55-15.12 μg g(-1) for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors.

  8. TEM preparation methods and influence of radiation damage on the beam sensitive CaCO3 shell of Emiliania huxleyi.

    PubMed

    Hoffmann, Ramona; Wochnik, Angela S; Betzler, Sophia B; Matich, Sonja; Griesshaber, Erika; Schmahl, Wolfgang W; Scheu, Christina

    2014-07-01

    The ultrastructure of biologically formed calcium carbonate crystals like the shell of Emiliania huxleyi depends on the environmental conditions such as pH value, temperature and salinity. Therefore, they can be used as indicator for climate changes. However, for this a detailed understanding of their crystal structure and chemical composition is required. High resolution methods like transmission electron microscopy can provide those information on the nanoscale, given that sufficiently thin samples can be prepared. In our study, we developed sample preparation techniques for cross-section and plan-view investigations and studied the sample stability under electron bombardment. In addition to the biological material (Emiliania huxleyi) we also prepared mineralogical samples (Iceland spar) for comparison. High resolution transmission electron microscopy imaging, electron diffraction and electron energy-loss spectroscopy studies revealed that all prepared samples are relatively stable under electron bombardment at an acceleration voltage of 300 kV when using a parallel illumination. Above an accumulated dose of ∼10(5) e/nm2 the material--independent whether its origin is biological or geological--transformed to poly-crystalline calcium oxide. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Does Addition of Propolis to Glass Ionomer Cement Alter its Physicomechanical Properties? An in Vitro Study.

    PubMed

    Subramaniam, P; Girish Babu, K L; Neeraja, G; Pillai, S

    Propolis is a natural resinous substance produced by honey bees. The antimicrobial effects of glass ionomer cement have been shown to improve with the addition of propolis; however its effect on the physicomechanical properties of the cement is not known. The purpose of this study was to evaluate the compressive strength and solubility of conventional restorative glass ionomer cement following the addition of propolis. Twenty half cylindrical samples were prepared with conventional restorative glass ionomer cement formed the control group. Another twenty samples were prepared with propolis added to conventional restorative glass ionomer cement formed the experimental group. The compressive strength was assessed using universal testing machine. To assess solubility, the samples were immersed in deionised water at room temperature, for 7 days. The solubility was measured as a difference in the weight of the sample; prior to immersion and following immersion at the end of each day. The control group had a significantly higher mean compressive strength of 146.26 Mpa as compared to the experimental group (135.06 Mpa). The solubility between the groups was significant. In comparison to the control group, incorporation of propolis to conventional restorative glass ionomer cement decreased the compressive strength significantly. The solubility of the cement in the experimental group increased significantly over 7day period as compared to the control group.

  10. Does Addition of Propolis to Glass Ionomer Cement Alter its Physicomechanical Properties? An In Vitro Study.

    PubMed

    Subramaniam, P; Girish Babu, K L; Neeraja, G; Pillai, S

    Propolis is a natural resinous substance produced by honey bees. The antimicrobial effects of glass ionomer cement have been shown to improve with the addition of propolis; however its effect on the physicomechanical properties of the cement is not known. The purpose of this study was to evaluate the compressive strength and solubility of conventional restorative glass ionomer cement following the addition of propolis. Twenty half cylindrical samples were prepared with conventional restorative glass ionomer cement formed the control group. Another twenty samples were prepared with propolis added to conventional restorative glass ionomer cement formed the experimental group. The compressive strength was assessed using universal testing machine. To assess solubility, the samples were immersed in deionised water at room temperature, for 7 days. The solubility was measured as a difference in the weight of the sample; prior to immersion and following immersion at the end of each day. The control group had a significantly higher mean compressive strength of 146.26 Mpa as compared to the experimental group (135.06 Mpa). The solubility between the groups was significant. In comparison to the control group, incorporation of propolis to conventional restorative glass ionomer cement decreased the compressive strength significantly. The solubility of the cement in the experimental group increased significantly over 7day period as compared to the control group.

  11. Reference samples for the earth sciences

    USGS Publications Warehouse

    Flanagan, F.J.

    1974-01-01

    A revised list of reference samples of interest to geoscientists has been extended to include samples for the agronomist, the archaeologist and the environmentalist. In addition to the source from which standard samples may be obtained, references or pertinent notes for some samples are included. The number of rock reference samples is now almost adequate, and the variety of ore samples will soon be sufficient. There are very few samples for microprobe work. Oil shales will become more important because of the outlook for world petroleum resources. The dryland equivalent of a submarine basalt might be useful in studies of sea-floor spreading and of the geochemistry of basalts. The Na- and K-feldspars of BCS (British Chemical Standards-Bureau of Analysed Samples), NBS (National Bureau of Standards), and ANRT (Association Kationale de la Recherche Technique) could serve as trace-element standards if such data were available. Similarly, the present NBS flint and plastic clays, as well as their predecessors, might be useful for archaeological pottery studies. The International Decade for Ocean Exploration may stimulate the preparation of ocean-water standards for trace elements or pollutants and a standard for manganese nodules. ?? 1974.

  12. A lab-on-a-chip system with integrated sample preparation and loop-mediated isothermal amplification for rapid and quantitative detection of Salmonella spp. in food samples.

    PubMed

    Sun, Yi; Quyen, Than Linh; Hung, Tran Quang; Chin, Wai Hoe; Wolff, Anders; Bang, Dang Duong

    2015-04-21

    Foodborne disease is a major public health threat worldwide. Salmonellosis, an infectious disease caused by Salmonella spp., is one of the most common foodborne diseases. Isolation and identification of Salmonella by conventional bacterial culture or molecular-based methods are time consuming and usually take a few hours to days to complete. In response to the demand for rapid on line or on site detection of pathogens, in this study, we describe for the first time an eight-chamber lab-on-a-chip (LOC) system with integrated magnetic bead-based sample preparation and loop-mediated isothermal amplification (LAMP) for rapid and quantitative detection of Salmonella spp. in food samples. The whole diagnostic procedures including DNA isolation, isothermal amplification, and real-time detection were accomplished in a single chamber. Up to eight samples could be handled simultaneously and the system was capable to detect Salmonella at concentration of 50 cells per test within 40 min. The simple design, together with high level of integration, isothermal amplification, and quantitative analysis of multiple samples in short time, will greatly enhance the practical applicability of the LOC system for rapid on-site screening of Salmonella for applications in food safety control, environmental surveillance, and clinical diagnostics.

  13. Ammonium Bicarbonate Addition Improves the Detection of Proteins by Desorption Electrospray Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Honarvar, Elahe; Venter, Andre R.

    2017-06-01

    The analysis of protein by desorption electrospray ionization mass spectrometry (DESI-MS) is considered impractical due to a mass-dependent loss in sensitivity with increase in protein molecular weights. With the addition of ammonium bicarbonate to the DESI-MS analysis the sensitivity towards proteins by DESI was improved. The signal to noise ratio (S/N) improvement for a variety of proteins increased between 2- to 3-fold relative to solvent systems containing formic acid and more than seven times relative to aqueous methanol spray solvents. Three methods for ammonium bicarbonate addition during DESI-MS were investigated. The additive delivered improvements in S/N whether it was mixed with the analyte prior to sample deposition, applied over pre-prepared samples, or simply added to the desorption spray solvent. The improvement correlated well with protein pI but not with protein size. Other ammonium or bicarbonate salts did not produce similar improvements in S/N, nor was this improvement in S/N observed for ESI of the same samples. As was previously described for ESI, DESI also caused extensive protein unfolding upon the addition of ammonium bicarbonate. [Figure not available: see fulltext.

  14. Urea free and more efficient sample preparation method for mass spectrometry based protein identification via combining the formic acid-assisted chemical cleavage and trypsin digestion.

    PubMed

    Wu, Shuaibin; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-10-30

    A formic acid (FA)-assisted sample preparation method was presented for protein identification via mass spectrometry (MS). Detailedly, an aqueous solution containing 2% FA and dithiothreitol was selected to perform protein denaturation, aspartic acid (D) sites cleavage and disulfide linkages reduction simultaneously at 108°C for 2h. Subsequently, FA wiped off via vacuum concentration. Finally, iodoacetamide (IAA) alkylation and trypsin digestion could be performed ordinally. A series of model proteins (BSA, β-lactoglobulin and apo-Transferrin) were treated respectively using such method, followed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The identified peptide number was increased by ∼ 80% in comparison with the conventional urea-assisted sample preparation method. Moreover, BSA identification was achieved efficiently down to femtomole (25 ± 0 sequence coverage and 16 ± 1 peptides) via such method. In contrast, there were not peptides identified confidently via the urea-assisted method before desalination via the C18 zip tip. The absence of urea in this sample preparation method was an advantage for the more favorable digestion and MALDI-TOF MS analysis. The performances of two methods for the real sample (rat liver proteome) were also compared, followed by a nanoflow reversed-phase liquid chromatography with electrospray ionization tandem mass spectrometry system analysis. As a result, 1335 ± 43 peptides were identified confidently (false discovery rate <1%) via FA-assisted method, corresponding to 295 ± 12 proteins (of top match=1 and requiring 2 unique peptides at least). In contrast, there were only 1107 ± 16 peptides (corresponding to 231 ± 10 proteins) obtained from the conventional urea-assisted method. It was serving as a more efficient protein sample preparation method for researching specific proteomes better, and providing assistance to develop other proteomics analysis methods

  15. Influence of sample preparation on lipidomics analysis of polar lipids in adipose tissue.

    PubMed

    López-Bascón, M A; Calderón-Santiago, M; Sánchez-Ceinos, J; Fernández-Vega, A; Guzmán-Ruiz, R; López-Miranda, J; Malagon, M M; Priego-Capote, F

    2018-01-15

    The main limitations of lipidomics analysis are the chemical complexity of the lipids, the range of concentrations at which they exist, and the variety of samples usually analyzed. These limitations particularly affect the characterization of polar lipids owing to the interference of neutral lipids, essentially acylglycerides, which are at high concentration and suppress ionization of low concentrated lipids in mass spectrometry detection. The influence of sample preparation on lipidomics analysis of polar lipids in adipose tissue by LC-MS/MS was the aim of this research. Two common extractants used for lipids isolation, methanol:chloroform (MeOH:CHCl 3 ) and methyl tert-butyl ether (MTBE), were qualitatively and quantitatively compared for the extraction of the main families of lipids. The obtained results showed that each family of lipids is influenced differently by the extractant used. However, as a general trend, the use of MTBE as extractant led to higher extraction efficiency for unsaturated fatty acids, glycerophospholipids and ceramides, while MeOH:CHCl 3 favored the isolation of saturated fatty acids and plasmalogens. The implementation of a solid-phase extraction (SPE) step for selective isolation of glycerophospholipids prior to LC-MS/MS analysis was assayed to evaluate its influence on lipids detection coverage as compared to direct analysis. This step was critical to enhance the detection coverage of glycerophospholipids by removal of ionization suppression effects caused by acylglycerides. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Preparation and Characterization of Nanosized Bi-Doped SnO₂/Reduced Graphene Oxide 3D Hybrids for Visible-Light-Driven Photocatalysis.

    PubMed

    Wu, Xiang-Feng; Zhang, Chen-Xu; Sun, Yang; Fu, Shi-Da; Li, Hui; Wang, Yi-Jin; Zhang, Jia-Rui; Su, Jun-Zhang; Wang, Yi-Wei; Wang, Kai-Yuan

    2018-07-01

    The nanosized Bi-doped SnO2/reduced graphene oxide 3D hybrids have been synthesized via one-step hydrothermal method. The structures, morphologies, photocatalytic activities of the as-prepared samples were discussed, respectively. The formation mechanism of the as-prepared hybrids was also proposed. Experimental results indicated that the usage amount of Bi2Sn2O7 obviously affected the photocatalytic performance of the as-prepared products. When it was 450 mg, the as-prepared sample possessed the band gap energy of 1.9 eV and the photocatalytic efficiency of 90% in 210 min for degradation of rhodamine B solution. In addition, triethylene tetramine and the as-prepared carbon hydrogel could act as reductant to synergistically reduce Bi2Sn2O7 into Bi-doped SnO2 particles during the formation of the hybrids.

  17. Preparation of Polyethylene Composites Containing Silver(I) Acylpyrazolonato Additives and SAR Investigation of their Antibacterial Activity.

    PubMed

    Marchetti, Fabio; Palmucci, Jessica; Pettinari, Claudio; Pettinari, Riccardo; Marangoni, Mirko; Ferraro, Stefano; Giovannetti, Rita; Scuri, Stefania; Grappasonni, Iolanda; Cocchioni, Mario; Maldonado Hodar, Francisco José; Gunnella, Roberto

    2016-11-02

    Novel composite materials PEn (n = 1-9) have been prepared by an easily up-scalable embedding procedure of three different families of Ag(I) acylpyrazolonato complexes in polyethylene (PE) matrix. In details, PE1-PE3 composites contain polynuclear [Ag(Q R )] n complexes, PE4-PE6 contain mononuclear [Ag(Q R )(L) m ] complexes and PE7-PE9 are loaded with mononuclear [Ag(Q R ) (PPh 3 ) 2 ] complexes, respectively (where L = 1-methylimidazole or 2-ethylimidazole, m = 1 or 2, and HQ R = 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, where in detail HQ fb , R = -CF 2 CF 2 CF 3 ; HQ cy , R = -cyclo-C 6 H 11 ; HQ be , R = -C(H)═C(CH 3 ) 2 ). The PEn composites, prepared by using a 1:1000 w/w silver additive/polyethylene ratio, have been characterized in bulk by IR spectroscopy and TGA analyses, which confirmed that the properties of polyethylene matrix are essentially unchanged. AFM, SEM, and EDX surface techniques show that silver additives form agglomerates with dimensions 10-100 μm on the polyethylene surface, with a slight increment of surface roughness of pristine plastic within 50 nm. However, the elastic properties of the composites are essentially the same of PE. The antibacterial activity of all composites has been tested against three bacterial strains (E. coli, P. aeruginosa and S. aureus) and results show that two classes of composites, PE1-PE3 and PE4-PE6, display high and persistent bactericidal and bacteriostatic activity, comparable to PE embedded with AgNO 3 . By contrast, composites PE7-PE9 exhibit a reduced antibacterial action. Contact and release tests in several conditions for specific migration of Ag + from plastics, indicate a very limited but time persistent release of silver ions from PE1-PE6 composites, thus suggesting that they are potential antibacterial materials for future applications. Instead, PE7-PE9 almost do not release silver, only trace levels of silver ions being detected, in accordance with their reduced antibacterial action. None of

  18. Determination of Slake Durability Index (Sdi) Values on Different Shape of Laminated Marl Samples

    NASA Astrophysics Data System (ADS)

    Ankara, Hüseyin; Çiçek, Fatma; Talha Deniz, İsmail; Uçak, Emre; Yerel Kandemir, Süheyla

    2016-10-01

    The slake durability index (SDI) test is widely used to determine the disintegration characteristic of the weak and clay-bearing rocks in geo-engineering problems. However, due to the different shapes of sample pieces, such as, irregular shapes displayed mechanical breakages in the slaking process, the SDI test has some limitations that affect the index values. In addition, shape and surface roughness of laminated marl samples have a severe influence on the SDI. In this study, a new sample preparation method called Pasha Method was used to prepare spherical specimens from the laminated marl collected from Seyitomer collar (SLI). Moreover the SDI tests were performed on equal size and weight specimens: three sets with different shapes were used. The three different sets were prepared as the test samples which had sphere shape, parallel to the layers in irregular shape, and vertical to the layers in irregular shape. Index values were determined for the three different sets subjected to the SDI test for 4 cycles. The index values at the end of fourth cycle were found to be 98.43, 98.39 and 97.20 %, respectively. As seen, the index values of the sphere sample set were found to be higher than irregular sample sets.

  19. Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography-tandem mass spectrometry.

    PubMed

    Petrarca, Mateus Henrique; Ccanccapa-Cartagena, Alexander; Masiá, Ana; Godoy, Helena Teixeira; Picó, Yolanda

    2017-05-12

    A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and salting-out assisted liquid-liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75-120%) and precision (RSD values≤16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the analytical selectivity required for the monitoring of the insecticides in fruit-, cereal- and milk-based baby foods. SALLE, recognized by cost-effectiveness, and simple and fast execution, provided a lower enrichment factor, consequently, higher limits of quantification (LOQs) were obtained. Some of them too high to meet the strict legislation regarding baby food. Nonetheless, the combination of ultrasound and DLLME also resulted in a high sample throughput and environmental-friendly method, whose LOQs were lower than the default maximum residue limit (MRL) of 10μgkg -1 set by European Community for baby foods. In the commercial baby foods analyzed, cyhalothrin and etofenprox were detected in different samples, demonstrating the suitability of proposed method for baby food control. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. HPLC-MS/MS analysis of anthocyanins in human plasma and urine using protein precipitation and dilute-and-shoot sample preparation methods, respectively.

    PubMed

    Liu, Junguo; Song, Jiuxue; Huang, Karen; Michel, Deborah; Fang, Jim

    2018-05-01

    A high-performance liquid chromatography tandem-mass spectrometry (HPLC-MS/MS) method has been developed to analyze anthocyanins in urine and plasma to further understand their absorption, distribution, metabolism and excretion. The method employed a Synergi RP-Max column (250 × 4.6 mm, 4 μm) and an API 4000 mass spectrometer. A gradient elution system consisted of mobile phase A (water-1% formic acid) and mobile phase B (acetonitrile) with a flow rate of 0.60 mL/min. The gradient was initiated at 5% B, increased to 21% B at 20 min, and then increased to 40% B at 35 min. The analysis of anthocyanins presents a challenge because of the poor stability of anthocyanins during sample preparation, especially during solvent evaporation. In this method, the degradation of anthocyanins was minimized using protein precipitation and dilute-and-shoot and sample preparation methods for plasma and urine, respectively. No interferences were observed from endogenous compounds. The method has been used to analyze anthocyanin concentrations in urine and plasma samples from volunteers administered saskatoon berries. Cyanidin-3-galactoside, cyanidin-3-glucoside, cyanidin-3-arabinoside, cyanidin-3-xyloside and quercetin-3-galactoside, the five major flavonoid components in saskatoon berries, were identified in plasma and urine samples. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Microsystem strategies for sample preparation in biological detection.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    James, Conrad D.; Galambos, Paul C.; Bennett, Dawn Jonita

    2005-03-01

    The objective of this LDRD was to develop microdevice strategies for dealing with samples to be examined in biological detection systems. This includes three sub-components: namely, microdevice fabrication, sample delivery to the microdevice, and sample processing within the microdevice. The first component of this work focused on utilizing Sandia's surface micromachining technology to fabricate small volume (nanoliter) fluidic systems for processing small quantities of biological samples. The next component was to develop interfaces for the surface-micromachined silicon devices. We partnered with Micronics, a commercial company, to produce fluidic manifolds for sample delivery to our silicon devices. Pressure testing was completedmore » to examine the strength of the bond between the pressure-sensitive adhesive layer and the silicon chip. We are also pursuing several other methods, both in house and external, to develop polymer-based fluidic manifolds for packaging silicon-based microfluidic devices. The second component, sample processing, is divided into two sub-tasks: cell collection and cell lysis. Cell collection was achieved using dielectrophoresis, which employs AC fields to collect cells at energized microelectrodes, while rejecting non-cellular particles. Both live and dead Staph. aureus bacteria have been collected using RF frequency dielectrophoresis. Bacteria have been separated from polystyrene microspheres using frequency-shifting dielectrophoresis. Computational modeling was performed to optimize device separation performance, and to predict particle response to the dielectrophoretic traps. Cell lysis is continuing to be pursued using microactuators to mechanically disrupt cell membranes. Novel thermal actuators, which can generate larger forces than previously tested electrostatic actuators, have been incorporated with and tested with cell lysis devices. Significant cell membrane distortion has been observed, but more experiments need to be

  2. Influence of the Addition of Minced Fish on the Preparation of Fish Sausage: Effects on Sensory Properties.

    PubMed

    Lago, Amanda M T; Vidal, Ana C C; Schiassi, Maria C E V; Reis, Tatiana; Pimenta, Carlos; Pimenta, Maria E S G

    2017-02-01

    In this study, we evaluated the effect of minced fish (MF) inclusion on the acceptance of tilapia sausages. One hundred consumers participated in the sensory acceptance test in relation to the attributes appearance, color, aroma, flavor, texture, overall impression, and purchase intent. The tests were conducted using the same composition of ingredients, varying only the raw material (MF and fillet), resulting in 5 different formulations. To represent the results of the sensory attributes, we generated internal preference maps through principal component analysis and parallel factor analysis, as well as frequency histograms. The data showed greater acceptability for the sample produced with 50% MF, although all had shown satisfactory results. We conclude that inclusion of MF can be suitable in the preparation of fish sausage due to high consumer acceptance. © 2017 Institute of Food Technologists®.

  3. A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

    NASA Technical Reports Server (NTRS)

    Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

    2016-01-01

    The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

  4. Surface and catalytic properties of acid metal carbons prepared by the sol gel method

    NASA Astrophysics Data System (ADS)

    Aguado-Serrano, J.; Rojas-Cervantes, M. L.; Martín-Aranda, R. M.; López-Peinado, A. J.; Gómez-Serrano, V.

    2006-06-01

    The sol-gel method has been applied for the synthesis of a series of acid metal-carbon xerogels (with M = V, Cr, Mo and Ni) by polymerisation of resorcinol with formaldehyde in the presence of metallic precursors. A blank sample was also prepared without any metal addition. The xerogels were heated in nitrogen at 1000 °C to obtain the pyrolysed products. The samples were characterised by different techniques such as thermal-mass spectrometry analysis, gas physisorption, and mercury porosimetry. In addition, the acid character of the pyrolysed products was tested by the Claisen-Schmidt condensation between benzaldehyde and acetophenone for the formation of chalcones.

  5. A Green Analytical Method Using Ultrasound in Sample Preparation for the Flow Injection Determination of Iron, Manganese, and Zinc in Soluble Solid Samples by Flame Atomic Absorption Spectrometry

    PubMed Central

    Yebra, M. Carmen

    2012-01-01

    A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5–30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2–4.6%) and a sample throughput of ca. 25 samples h–1 were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4–25.61 μg g−1 for iron, 5.74–18.30 μg g−1 for manganese, and 33.27–57.90 μg g−1 for zinc in soluble solid food samples and 3.75–9.90 μg g−1 for iron, 0.47–5.05 μg g−1 for manganese, and 1.55–15.12 μg g−1 for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors. PMID:22567553

  6. The Effect of LAB as Probiotic Starter Culture and Green Tea Extract Addition on Dry Fermented Pork Loins Quality.

    PubMed

    Neffe-Skocińska, Katarzyna; Jaworska, Danuta; Kołożyn-Krajewska, Danuta; Dolatowski, Zbigniew; Jachacz-Jówko, Luiza

    2015-01-01

    The objective of this study was to evaluate the microbiological, physicochemical, and sensory quality of dry fermented pork loin produced with the addition of Lb. rhamnosus LOCK900 probiotic strain, 0.2% glucose, and 1.5% green tea extract. Three loins were prepared: control sample (P0: no additives), sample supplemented with glucose and probiotic strain (P1), and sample with glucose, green tea extract, and probiotic (P2). The samples were analyzed after 21 days of ripening and 180 days of storage. The results indicated that the highest count of LAB was observed both in the samples: with probiotic and with probiotic and green tea extract (7.00 log cfu/g after ripening; 6.00 log cfu/g after storage). The oxidation-reduction potential values were lower in the probiotic loin samples. Probiotic and green tea extract have not caused color changes of study loins during storage. The study demonstrated that an addition of probiotic and green tea extract to dry fermented loins is possible and had no impact on sensory quality after product storage.

  7. The Effect of LAB as Probiotic Starter Culture and Green Tea Extract Addition on Dry Fermented Pork Loins Quality

    PubMed Central

    Jaworska, Danuta; Kołożyn-Krajewska, Danuta; Dolatowski, Zbigniew; Jachacz-Jówko, Luiza

    2015-01-01

    The objective of this study was to evaluate the microbiological, physicochemical, and sensory quality of dry fermented pork loin produced with the addition of Lb. rhamnosus LOCK900 probiotic strain, 0.2% glucose, and 1.5% green tea extract. Three loins were prepared: control sample (P0: no additives), sample supplemented with glucose and probiotic strain (P1), and sample with glucose, green tea extract, and probiotic (P2). The samples were analyzed after 21 days of ripening and 180 days of storage. The results indicated that the highest count of LAB was observed both in the samples: with probiotic and with probiotic and green tea extract (7.00 log cfu/g after ripening; 6.00 log cfu/g after storage). The oxidation-reduction potential values were lower in the probiotic loin samples. Probiotic and green tea extract have not caused color changes of study loins during storage. The study demonstrated that an addition of probiotic and green tea extract to dry fermented loins is possible and had no impact on sensory quality after product storage. PMID:25961018

  8. Investigation of the visible light photocatalytic activity of BiVO4 prepared by sol gel method assisted by ultrasonication.

    PubMed

    Deebasree, J P; Maheskumar, V; Vidhya, B

    2018-07-01

    Visible light induced photocatalyst BiVO 4 with monoclinic scheelite structure has been synthesised via sol gel method assisted by ultrasonication. The prepared samples were characterised using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffused reflectance spectroscopy (DRS) techniques. The photocatalytic efficiency was evaluated by decolourisation of MB under visible light irradiation. The effect of ultrasound output power on the properties of BiVO 4 during and after preparation by sol-gel method has been compared with normal agitated sample (As prepared). The power of ultrasonic vibration has been varied and an ideal output power which yields better catalytic efficiency is determined. BiVO 4 sonicated with 80 W during preparation 80 W (D) exhibited relatively high surface area, better surface morphology and better catalytic efficiency compared to other samples which were sonicated with 100, 160 and 200 W. The results signify that the photodegradation rate of BiVO 4 80 W (D) sample is high up to 96% in 90 min compared to other samples. Change in morphology leading to better catalytic efficiency was obtained just by exposing the sample to ultrasonic radiation without addition of any surfactant. The recovery test showed that the sample was stable for four consecutive cycles. Using radical test, a reasonable mechanism for photodegradation has been proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Genotoxicity testing of cooked cured meat pigment (CCMP) and meat emulsion coagulates prepared with CCMP.

    PubMed

    Stevanović, M; Cadez, P; Zlender, B; Filipic, M

    2000-07-01

    The preformed cooked cured meat pigment (CCMP) synthesized directly from bovine red blood cells or through a hemin intermediate was found to be a viable colorant for application to comminuted pork as a nitrite substitute. However the genotoxicity of CCMP and meat emulsion coagulates prepared with CCMP has not been evaluated. Therefore the objectives of this work were to investigate genotoxicity of CCMP and the influence of CCMP addition on genotoxicity and the content of residual nitrite in model meat emulsion coagulates. Meat emulsions were prepared from white (musculus longissimus dorsi) and red (musculus quadriceps femoris) pork muscles with two different amounts of synthesized pigment CCMP. Comparatively, emulsions with fixed addition of nitrite salt and emulsions without any addition for color development were made. Genotoxicity of CCMP and meat emulsion coagulates was tested with the SOS/umu test and the Ames test. Neither CCMP nor meat emulsion coagulates prepared with CCMP or nitrite salt were genotoxic in the SOS/umu test. In the Ames test using Salmonella Typhimurium strains TA98 and TA100 samples of coagulates prepared with CCMP and with nitrite showed weak mutagenic activity in Salmonella Typhimurium strain TA100 but only in the absence of the metabolic activation, while CCMP was not mutagenic. Coagulates prepared with CCMP contained significantly less residual nitrite than coagulates prepared with nitrite salt. These results indicate that from the human health standpoint the substitution of nitrite salt with CCMP would be highly recommendable.

  10. Ultrastructure of Plant Leaf Cuticles in relation to Sample Preparation as Observed by Transmission Electron Microscopy

    PubMed Central

    Guzmán, Paula; Fernández, Victoria; García, María Luisa; Fernández, Agustín; Gil, Luis

    2014-01-01

    The leaf cuticular ultrastructure of some plant species has been examined by transmission electron microscopy (TEM) in only few studies. Attending to the different cuticle layers and inner structure, plant cuticles have been grouped into six general morphological types. With the aim of critically examining the effect of cuticle isolation and preparation for TEM analysis on cuticular ultrastructure, adaxial leaf cuticles of blue-gum eucalypt, grey poplar, and European pear were assessed, following a membrane science approach. The embedding and staining protocols affected the ultrastructure of the cuticles analysed. The solubility parameter, surface tension, and contact angles with water of pure Spurr's and LR-White resins were within a similar range. Differences were however estimated for resin : solvent mixtures, since Spurr's resin is combined with acetone and LR-White resin is mixed with ethanol. Given the composite hydrophilic and lipophilic nature of plant cuticles, the particular TEM tissue embedding and staining procedures employed may affect sample ultrastructure and the interpretation of the results in physicochemical and biological terms. It is concluded that tissue preparation procedures may be optimised to facilitate the observation of the micro- and nanostructure of cuticular layers and components with different degrees of polarity and hydrophobicity. PMID:24895682

  11. Surface Cleaning Techniques: Ultra-Trace ICP-MS Sample Preparation and Assay of HDPE

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Overman, Nicole R.; Hoppe, Eric W.; Addleman, Raymond S.

    2013-06-01

    The world’s most sensitive radiation detection and assay systems depend upon ultra-low background (ULB) materials to reduce unwanted radiological backgrounds. Herein, we evaluate methods to clean HDPE, a material of interest to ULB systems and the means to provide rapid assay of surface and bulk contamination. ULB level material and ultra-trace level detection of actinide elements is difficult to attain, due to the introduction of contamination from sample preparation equipment such as pipette tips, sample vials, forceps, etc. and airborne particulate. To date, literature available on the cleaning of such polymeric materials and equipment for ULB applications and ultra-trace analysesmore » is limited. For these reasons, a study has been performed to identify an effective way to remove surface contamination from polymers in an effort to provide improved instrumental detection limits. Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was utilized to assess the effectiveness of a variety of leachate solutions for removal of inorganic uranium and thorium surface contamination from polymers, specifically high density polyethylene (HDPE). HDPE leaching procedures were tested to optimize contaminant removal of thorium and uranium. Calibration curves for thorium and uranium ranged from 15 ppq (fg/mL) to 1 ppt (pg/mL). Detection limits were calculated at 6 ppq for uranium and 7 ppq for thorium. Results showed the most effective leaching reagent to be clean 6 M nitric acid for 72 hour exposures. Contamination levels for uranium and thorium found in the leachate solutions were significant for ultralow level radiation detection applications.« less

  12. Tribological Performance of Ni3Al Matrix Self-Lubricating Composites Containing Multilayer Graphene Prepared by Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Yan, Zhao; Shi, Xiaoliang; Huang, Yuchun; Deng, Xiaobin; Liu, Xiyao; Yang, Kang

    2018-01-01

    In order to improve tribological performance of Ni3Al-based alloy, Ni3Al matrix composites containing 1.5 wt.% multilayer graphene (MLG) are prepared through additive manufacturing (AM) and spark plasma sintering (SPS), which are denoted as NMAM and NMSPS, respectively. Tribological behaviors of NMAM and NMSPS against Si3N4 balls are researched under constant speed (0.2 m/s) and varied loads (from 4 to 16 N) for evaluating the tribological properties of NMAM and NMSPS. The results present that NMAM exhibits the excellent tribological properties [low friction coefficients (0.26-0.40) and considerable wear resistance (2.8-4.6 × 10-5 mm3 N-1 m-1)] as compared to NMSPS, which attributes to the uniform enrichment of MLG with properties of high tensile strength and being easily sheared off on the worn surfaces. Owing to the use of spherical prealloyed powder containing multilayer graphene and the characteristics of layer by layer depositing in the AM process, NMAM has a more compact and uniform substrate, which persistently provides a source of the formation of continuous and stable frictional layer. Due to the characteristics of AM rapid solidification, NMAM has the small grain size and well-compacted microstructure, which can effectively reduce the probability of spalling wear and lead to the increase in wear resistance of materials. The research can offer the reference for self-lubricating materials prepared by AM technology.

  13. Automated sample-preparation technologies in genome sequencing projects.

    PubMed

    Hilbert, H; Lauber, J; Lubenow, H; Düsterhöft, A

    2000-01-01

    A robotic workstation system (BioRobot 96OO, QIAGEN) and a 96-well UV spectrophotometer (Spectramax 250, Molecular Devices) were integrated in to the process of high-throughput automated sequencing of double-stranded plasmid DNA templates. An automated 96-well miniprep kit protocol (QIAprep Turbo, QIAGEN) provided high-quality plasmid DNA from shotgun clones. The DNA prepared by this procedure was used to generate more than two mega bases of final sequence data for two genomic projects (Arabidopsis thaliana and Schizosaccharomyces pombe), three thousand expressed sequence tags (ESTs) plus half a mega base of human full-length cDNA clones, and approximately 53,000 single reads for a whole genome shotgun project (Pseudomonas putida).

  14. The Coronal Tooth Fractures: Preliminary Evaluation of a Three-Year Follow-Up of the Anterior Teeth Direct Fragment Reattachment Technique Without Additional Preparation.

    PubMed

    Giudice G, Lo; A, Alibrandi; F, Lipari; A, Lizio; F, Lauritano; G, Cervino; M, Cicciù

    2017-01-01

    The aim of this research is to describe and to analyse the long-term results and the clinical steps of direct fragment reattachment technique with no additional tooth preparation, used to treat crown fracture. This technique achieves the clinical success, combining satisfactory aesthetic and functional results with a minimally invasive approach. The 3 years follow-up included 9 patients (5 males, 4 females) with coronal fracture. In all the cases the fragment was available and intact. The authors illustrate the adhesive procedure used. Under local anaesthesia and after positioning the rubber dam, both the tooth and the fragment surface were etched, rinsed and applied by the adhesive system in order to obtain the retention of the fractured part to the tooth without additional tooth preparation or resin cement. The statistical analysis shows the good performances of direct fragment reattachment technique. After 36 months, in 22.2% of the cases, the detachment was observed of the bonded fragment and in 11.1% of patients, complications were recorded. Our clinical experience shows how the ultra-conservative procedure used is fast, easy and offers a long term predictability; it also allows good functional and aesthetic outcomes.

  15. Molecularly imprinted polymers for the detection of illegal drugs and additives: a review.

    PubMed

    Xiao, Deli; Jiang, Yue; Bi, Yanping

    2018-04-04

    This review (with 154 refs.) describes the current status of using molecularly imprinted polymers in the extraction and quantitation of illicit drugs and additives. The review starts with an introduction into some synthesis methods (lump MIPs, spherical MIPs, surface imprinting) of MIPs using illicit drugs and additives as templates. The next section covers applications, with subsections on the detection of illegal additives in food, of doping in sports, and of illicit addictive drugs. A particular focus is directed towards current limitations and challenges, on the optimization of methods for preparation of MIPs, their applicability to aqueous samples, the leakage of template molecules, and the identification of the best balance between adsorption capacity and selectivity factor. At last, the need for convincing characterization methods, the lack of uniform parameters for defining selectivity, and the merits and demerits of MIPs prepared using nanomaterials are addressed. Strategies are suggested to solve existing problems, and future developments are discussed with respect to a more widespread use in relevant fields. Graphical abstract This review gives a comprehensive overview of the advances made in molecularly imprinting of polymers for use in the extraction and quantitation of illicit drugs and additives. Methods for syntheses, highlighted applications, limitations and current challenges are specifically addressed.

  16. Preparation of Ag superhydrophobic surface on metal substrates

    NASA Astrophysics Data System (ADS)

    Li, J. Y.; Lu, S. X.; Xu, W. G.; Duan, Y. Q.; Yang, X. C.; Cheng, Y. Y.; He, G.; Cui, S.

    2018-01-01

    In this work, the facile approaches are developed for preparation the Ag superhydrophobic surfaces (SHSs) on zinc (Zn), copper (Cu) and aluminium (Al) substrates. The water contact angles (WCAs) of the Ag SHSs on Zn, Cu and Al substrates are 167°, 165° and 154°, respectively. Furthermore, the water sliding angle (WSA) of each surface is less than 1°. The morphology and chemical composition of the samples are characterized using scanning electron microscopy (SEM) and X-ray diffraction pattern (XRD). The as-prepared three kinds of SHSs possess the self-cleaning performance, which can quickly take the chalk away when the water droplets fall down the SHSs. In addition, the superhydrophobicity of the SHSs can well maintain after exposure to the air for 6 months, indicating that the surfaces can sustain good stability.

  17. Preparing for chemical terrorism: stability of injectable atropine sulfate.

    PubMed

    Schier, Joshua G; Ravikumar, Padinjarekuttu R; Nelson, Lewis S; Heller, Michael B; Howland, Mary Ann; Hoffman, Robert S

    2004-04-01

    A massive nerve agent attack may rapidly deplete in-date supplies of atropine. The authors considered using atropine beyond its labeled shelf life. The objective was to determine the stability of premixed injectable atropine sulfate samples with different expiration dates. This was an in-vitro study using gas chromatography and mass spectrometry (GC/MS). Four atropine solutions (labeled concentration of 400 microg/mL) ranging from in date to 12 years beyond expiration (exp) and an additional sample of atropine sulfate (labeled concentration of 2,000 microg/mL) obtained from a World War II era autoinjector were assayed for atropine stability. Standards of atropine sulfate and tropine were prepared and quantified by GC/MS. Study samples were prepared by adding a buffer solution to free the base, extracting with an isopropanol/methylene chloride mixture and followed by evaporating the organic layer to dryness. Pentafluoropropionic anhydride and pentafluoropropanol were then added as derivatization reagents. Study samples were heated, the derivitization reagents were evaporated, and the remaining compound was reconstituted in ethyl acetate for injection into the GC/MS. All solutions were clear and colorless. Atropine concentrations were as follows: in date, 252 microg/mL; 2001 exp, 290 microg/mL; 1999 exp, 314 microg/mL; 1990 exp, 398 microg/mL; and WW II specimen, 1,475 microg/mL. Tropine was found in concentrations of <10 microg/mL in all study samples. Significant amounts of atropine were found in all study samples. All samples remained clear and colorless, and no substantial amount of tropine was found in any study sample. Further testing is needed to determine clinical effect.

  18. LAMP assay and rapid sample preparation method for on-site detection of flavescence dorée phytoplasma in grapevine

    PubMed Central

    Kogovšek, P; Hodgetts, J; Hall, J; Prezelj, N; Nikolić, P; Mehle, N; Lenarčič, R; Rotter, A; Dickinson, M; Boonham, N; Dermastia, M; Ravnikar, M

    2015-01-01

    In Europe the most devastating phytoplasma associated with grapevine yellows (GY) diseases is a quarantine pest, flavescence dorée (FDp), from the 16SrV taxonomic group. The on-site detection of FDp with an affordable device would contribute to faster and more efficient decisions on the control measures for FDp. Therefore, a real-time isothermal LAMP assay for detection of FDp was validated according to the EPPO standards and MIQE guidelines. The LAMP assay was shown to be specific and extremely sensitive, because it detected FDp in all leaf samples that were determined to be FDp infected using quantitative real-time PCR. The whole procedure of sample preparation and testing was designed and optimized for on-site detection and can be completed in one hour. The homogenization procedure of the grapevine samples (leaf vein, flower or berry) was optimized to allow direct testing of crude homogenates with the LAMP assay, without the need for DNA extraction, and was shown to be extremely sensitive. PMID:26146413

  19. Preliminary study of neutron absorption by concrete with boron carbide addition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abdullah, Yusof, E-mail: yusofabd@nuclearmalaysia.gov.my; Yusof, Mohd Reusmaazran; Zali, Nurazila Mat

    2014-02-12

    Concrete has become a conventional material in construction of nuclear reactor due to its properties like safety and low cost. Boron carbide was added as additives in the concrete construction as it has a good neutron absorption property. The sample preparation for concrete was produced with different weight percent of boron carbide powder content. The neutron absorption rate of these samples was determined by using a fast neutron source of Americium-241/Be (Am-Be 241) and detection with a portable backscattering neutron detector. Concrete with 20 wt % of boron carbide shows the lowest count of neutron transmitted and this indicates themore » most neutrons have been absorbed by the concrete. Higher boron carbide content may affect the concrete strength and other properties.« less

  20. Preliminary study of neutron absorption by concrete with boron carbide addition

    NASA Astrophysics Data System (ADS)

    Abdullah, Yusof; Ariffin, Fatin Nabilah Tajul; Hamid, Roszilah; Yusof, Mohd Reusmaazran; Zali, Nurazila Mat; Ahmad, Megat Harun Al Rashid Megat; Yazid, Hafizal; Ahmad, Sahrim; Mohamed, Abdul Aziz

    2014-02-01

    Concrete has become a conventional material in construction of nuclear reactor due to its properties like safety and low cost. Boron carbide was added as additives in the concrete construction as it has a good neutron absorption property. The sample preparation for concrete was produced with different weight percent of boron carbide powder content. The neutron absorption rate of these samples was determined by using a fast neutron source of Americium-241/Be (Am-Be 241) and detection with a portable backscattering neutron detector. Concrete with 20 wt % of boron carbide shows the lowest count of neutron transmitted and this indicates the most neutrons have been absorbed by the concrete. Higher boron carbide content may affect the concrete strength and other properties.

  1. TiO2 anode materials for lithium-ion batteries with different morphology and additives

    NASA Astrophysics Data System (ADS)

    Liu, Xiang; Ng, Yip Hang; Leung, Yu Hang; Liu, Fangzhou; Djurišic, Aleksandra B.; Xie, Mao Hai; Chan, Wai Kin

    2014-03-01

    Electrochemical performances of different TiO2 nanostructures, TiO2/CNT composite and TiO2 with titanium isopropoxide (TTIP) treatment anode were investigated. For different TiO2 nanostructures, we investigated vertically aligned TiO2 nanotubes on Ti foil and TiO2 nanotube-powders fabricated by rapid breakdown anodization technique. The morphology of the prepared samples was characterized by scanning probe microscopy (SEM). The electrochemical lithium storage abilities were studied by galvanostatic method. In addition, carbon nanotubes (CNT) additives and solution treatment process of TiO2 anode were investigated, and the results show that the additives and treatment could enhance the cycling performance of the TiO2 anode on lithium ion batteries.

  2. Preparation of water samples for carbon-14 dating

    USGS Publications Warehouse

    Feltz, H.R.; Hanshaw, Bruce B.

    1963-01-01

    For most natural water, a large sample is required to provide the 3 grams of carbon needed for a carbon-14 determination. A field procedure for isolating total dissolved-carbonate species is described. Carbon dioxide gas is evolved by adding sulfuric acid to the water sample; the gas is then collected in a sodium hydroxide trap by recycling in a closed system. The trap is then transported to the dating laboratory where the carbon-14 is counted.

  3. High-throughput sample preparation and simultaneous column regeneration liquid chromatography-tandem mass spectrometry method for determination of nitrogen mustard metabolites in human urine.

    PubMed

    Reddy, Muntha K; Mills, Grier; Nixon, Christopher; Wyatt, Shane A; Croley, Timothy R

    2011-08-15

    Nitrogen mustards (NMs) are known to have DNA alkylation and strong vesicant properties. Their availability to terrorist organizations makes them a potential choice for chemical attacks on civilian populations. After an exposure, it is difficult to measure NMs directly because of their rapid metabolism in the human body. Therefore to determine an individual's level of exposure to NMs, it is necessary to analyze for NM metabolites being excreted by the body. The metabolites of NMs are generated by a hydrolysis reaction, and are easily detectable by liquid chromatography tandem mass spectrometry (LC-MS/MS). This work is focused on the development of a high-throughput assay for the quantitation of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) metabolites of bis (2-chloroethyl) ethylethanamine (HN1) and bis (2-chloroethyl) methylethanamine (HN2), respectively. The method uses automated 96-well plate sample preparation of human urine samples and a 2-position 10-port switching valve to allow for simultaneous regeneration of the liquid chromatography (LC) columns. Using this method, over 18 h was saved through the reduction of sample preparation and analysis time when compared to a conventional method for 96 samples. The validated method provided excellent accuracy for both EDEA (100.9%) and MDEA (100.6%) with precision better than 5.27% for each analyte. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Preparation of stir cake sorptive extraction based on polymeric ionic liquid for the enrichment of benzimidazole anthelmintics in water, honey and milk samples.

    PubMed

    Wang, Yulei; Zhang, Jie; Huang, Xiaojia; Yuan, Dongxing

    2014-08-20

    In this work, a new stir cake sorptive extraction (SCSE) using polymeric ionic liquid monolith as sorbent was prepared. The sorbent was obtained by in situ copolymerization of an ionic liquid, 1-allyl-3-methylimidazolium bis[(trifluoro methyl)sulfonyl]imide (AMII) and divinylbenzene (DB) in the presence of N,N-dimethylformamide. The influence of the content of ionic liquid and the porogen in the polymerization mixture on extraction performance was studied thoroughly. The physicochemical properties of the polymeric ionic liquid were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The usefulness of SCSE-AMIIDB was demonstrated by the enrichment of trace benzimidazole anthelmintics. Several parameters affecting the extraction efficiency were investigated, and under the optimized conditions, a simple and effective method for the determination of trace benzimidazoles residues in water, milk and honey samples was established by coupling SCSE-AMIIDB with high performance liquid chromatography/diode array detection (SCSE-AMIIDB-HPLC/DAD). Results indicated that the limits of detection (S/N=3) for target compounds were 0.020-0.072 μg L(-1), 0.035-0.10 μg L(-1) and 0.026-0.076 μg L(-1) in water, milk and honey samples, respectively. In addition, an acceptable reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations (RSD) of less than 9% and 11%, respectively. Finally, the established AMII-SCSE-HPLC/DAD method was successfully applied for the determination of benzimidazoles residues in milk, honey and environmental water samples. Recoveries obtained for the determination of benzimidazole anthelmintics in spiking samples ranged from 70.2% to 117.6%, with RSD below 12% in all cases. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effect of chitosan addition to characteristic and antimicrobial activity of zinc doped hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Rasyida, A.; Wicaksono, S. T.; Pradita, N. N.; Ardhyananta, H.; Purnomo, A.

    2017-07-01

    Hydroxyapatite (HAp) doping with zinc was prepared using sol gel method; different chitosan content were further added to prepare the composite, namely 10, 15 and 20% wt. The samples were characterized using FTIR, XRD, SEM-EDX, and AAS. In vitro antimicrobial activities of the composite were evaluated against gram positive and negative bacteria. FTIR results revealed that there were no important changes in the structure of composite, while 10% wt of chitosan in composite shows the highest inhibition zone against Escherichia coli after 24 h incubation. In addition, after 7 days of immersion in simulated body fluid, there were apatite formations in the surface of the composite. These might indicate that this composite could be used as a material candidate for bone substitute applications.

  6. Preparation and application of poly 3, 4-ethylenedioxythiophene (PEDOT) nanofibers in the pretreatment of samples before the determination of elements in children fingernails

    NASA Astrophysics Data System (ADS)

    Qiu, J. L.; Kang, X. J.; Ma, L.; Huang, W. Y.; Ge, Q. Y.

    2015-07-01

    Solid phase extraction (SPE) has been used widely for sample preparation in the analytical process. Many efforts have focused on developing novel adsorbents to enrich and purify the analytes effectively. In this study, poly-3, 4-ethylenedioxythiophene (PEDOT) nanofiber was prepared and used as the SPE adsorbent. The fiber performed good in extraction of metal ions, Cd, Sn, Hg, Pb, Al, and As, with the extraction recoveries ranged from 53.9% to 99.6% in the wet digested samples of fingernails. A PEDOT namofibers SPE column coupled with ICP-MS was established for assay of elements in fingernails. The levels of elements (Cd, Sn, Hg, Pb, Al, and As) in the fingernails of 77 healthy Chinese children (6-7 and 10-11 years) were determined. Independent t test shows that no significance has been found between boys and girls. On the contrary, there was obvious difference on the levels of most elements between the two grade groups.

  7. Evaluation of automated sample preparation, retention time locked gas chromatography-mass spectrometry and data analysis methods for the metabolomic study of Arabidopsis species.

    PubMed

    Gu, Qun; David, Frank; Lynen, Frédéric; Rumpel, Klaus; Dugardeyn, Jasper; Van Der Straeten, Dominique; Xu, Guowang; Sandra, Pat

    2011-05-27

    In this paper, automated sample preparation, retention time locked gas chromatography-mass spectrometry (GC-MS) and data analysis methods for the metabolomics study were evaluated. A miniaturized and automated derivatisation method using sequential oximation and silylation was applied to a polar extract of 4 types (2 types×2 ages) of Arabidopsis thaliana, a popular model organism often used in plant sciences and genetics. Automation of the derivatisation process offers excellent repeatability, and the time between sample preparation and analysis was short and constant, reducing artifact formation. Retention time locked (RTL) gas chromatography-mass spectrometry was used, resulting in reproducible retention times and GC-MS profiles. Two approaches were used for data analysis. XCMS followed by principal component analysis (approach 1) and AMDIS deconvolution combined with a commercially available program (Mass Profiler Professional) followed by principal component analysis (approach 2) were compared. Several features that were up- or down-regulated in the different types were detected. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Study of sample preparation for determination of endocannabinoids and analogous compounds in human serum by LC-MS/MS in MRM mode.

    PubMed

    Luque-Córdoba, D; Calderón-Santiago, M; Luque de Castro, M D; Priego-Capote, F

    2018-08-01

    Endocannabinoids are lipids with a key role in physiological processes such as the immune response or the metabolism. This involvement explains their association to pathologies such as cancer, obesity or multiple sclerosis. The determination of endocannabinoids constitutes a challenge for clinical laboratories due to the variety of biological matrices and the wide range of concentrations at which they can be found. This research deals with the comparison of three sample preparation strategies (viz., on-line SPE, off-line SPE for interferents removal, and protein precipitation) for subsequent LC-MS/MS analysis of 14 endocannabinoids and analogous compounds in serum. As a result, the on-line coupling between SPE and LC-MS/MS is proposed as the best approach for this determination. The proposed method allows full automation of the overall process, shortening of the analysis time, and avoidance of errors associated with sample preparation steps. The improvement in sensitivity and selectivity thus achieved allows obtaining quantification limits at the pg mL -1 level, which makes possible the application of the method for clinical studies. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Thermal conductivity enhancement and sedimentation reduction of magnetorheological fluids with nano-sized Cu and Al additives

    NASA Astrophysics Data System (ADS)

    Rahim, M. S. A.; Ismail, I.; Choi, S. B.; Azmi, W. H.; Aqida, S. N.

    2017-11-01

    This work presents enhanced material characteristics of smart magnetorheological (MR) fluids by utilizing nano-sized metal particles. Especially, enhancement of thermal conductivity and reduction of sedimentation rate of MR fluids those are crucial properties for applications of MR fluids are focussed. In order to achieve this goal, a series of MR fluid samples are prepared using carbonyl iron particles (CIP) and hydraulic oil, and adding nano-sized particles of copper (Cu), aluminium (Al), and fumed silica (SiO2). Subsequently, the thermal conductivity is measured by the thermal property analyser and the sedimentation of MR fluids is measured using glass tubes without any excitation for a long time. The measured thermal conductivity is then compared with theoretical models such as Maxwell model at various CIP concentrations. In addition, in order to show the effectiveness of MR fluids synthesized in this work, the thermal conductivity of MRF-132DG which is commercially available is measured and compared with those of the prepared samples. It is observed that the thermal conductivity of the samples is much better than MRF-132DG showing the 148% increment with 40 vol% of the magnetic particles. It is also observed that the sedimentation rate of the prepared MR fluid samples is less than that of MRF-132DG showing 9% reduction with 40 vol% of the magnetic particles. The mixture optimized sample with high conductivity and low sedimentation was also obtained. The magnetization of the sample recorded an enhancement of 70.5% when compared to MRF-132DG. Furthermore, the shear yield stress of the sample were also increased with and without the influence of magnetic field.

  10. Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bannochie, C. J.

    2016-02-04

    The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken priormore » to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.« less

  11. Sieve-based device for MALDI sample preparation. I. Influence of sample deposition conditions in oligonucleotide analysis to achieve significant increases in both sensitivity and resolution.

    PubMed

    Molin, Laura; Cristoni, Simone; Crotti, Sara; Bernardi, Luigi Rossi; Seraglia, Roberta; Traldi, Pietro

    2008-11-01

    Spraying of oligonucleotide-matrix solutions through a stainless steel (ss) sieve (38 microm, 450 mesh) leads to the formation, on the matrix-assisted laser desorption/ionization (MALDI) sample holder, of uniformly distributed microcrystals, well separated from each other. When the resulting sample holder surface is irradiated by laser, abundant molecular species form, with a clear increase in both intensity and resolution with respect to values obtained by 'Dried Droplet', 'Double Layer', and 'Sandwich' deposition methods. In addition, unlike the usual situation, the sample is perfectly homogeneous, and identical spectra are obtained by irradiating different areas. On one hand, the data indicate that this method is highly effective for oligonucleotide MALDI analysis, and on the other, that it can be validly employed for fully automated MALDI procedures.

  12. Preparation of Diatomite Supported Nano Zinc Oxide Composite Photocatalytic Material and Study on its Formaldehyde Degradation

    NASA Astrophysics Data System (ADS)

    Xiao, Liguang; Pang, Bo

    2017-09-01

    This experiment used zinc nitrate as precursor, ethanol as solvent and polyethylene glycol as dispersant, diatomite as carrier, diatomite loaded nano Zinc Oxide was prepared by sol-gel method, in addition, the formaldehyde degradation was studied by two kinds of experimental methods: preparation and loading, preparation and post loading, The samples were characterized by SEM, XRD, BET and IR. Experimental results showed that: Diatomite based nano Zinc Oxide had a continuous adsorption and degradation of formaldehyde, formaldehyde gas with initial concentration was 0.7mg/m3, after 36h degradation, the concentration reached 0.238mg/m3, the degradation rate reached to 66%.

  13. Stochastic sampled-data control for synchronization of complex dynamical networks with control packet loss and additive time-varying delays.

    PubMed

    Rakkiyappan, R; Sakthivel, N; Cao, Jinde

    2015-06-01

    This study examines the exponential synchronization of complex dynamical networks with control packet loss and additive time-varying delays. Additionally, sampled-data controller with time-varying sampling period is considered and is assumed to switch between m different values in a random way with given probability. Then, a novel Lyapunov-Krasovskii functional (LKF) with triple integral terms is constructed and by using Jensen's inequality and reciprocally convex approach, sufficient conditions under which the dynamical network is exponentially mean-square stable are derived. When applying Jensen's inequality to partition double integral terms in the derivation of linear matrix inequality (LMI) conditions, a new kind of linear combination of positive functions weighted by the inverses of squared convex parameters appears. In order to handle such a combination, an effective method is introduced by extending the lower bound lemma. To design the sampled-data controller, the synchronization error system is represented as a switched system. Based on the derived LMI conditions and average dwell-time method, sufficient conditions for the synchronization of switched error system are derived in terms of LMIs. Finally, numerical example is employed to show the effectiveness of the proposed methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Stability of extemporaneously prepared moxifloxacin oral suspensions.

    PubMed

    Hutchinson, David J; Johnson, Cary E; Klein, Kristin C

    2009-04-01

    The stability of extemporaneously prepared moxifloxacin oral suspensions was studied. An oral suspension of moxifloxacin 20 mg/mL was prepared by thoroughly grinding three 400-mg tablets of moxifloxacin in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of either Ora-Sweet or Ora-Sweet SF were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of each formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and were stored at room temperature (23-25 degrees C). A 1-mL sample was withdrawn from each of the six bottles with a micropipette immediately after preparation and at 7, 14, 28, 60, and 90 days. After further dilution to an expected concentration of 8 microg/ mL with sample diluent, the samples were assayed in duplicate by stability-indicating high-performance liquid chromatography. Stability was defined as the retention of at least 90% of the initial concentration. At least 99% of the initial moxifloxacin remained throughout the 90-day study period in both preparations. There were no detectable changes in color, odor, taste, and pH and no visible microbial growth in any sample. Extemporaneously compounded suspensions of moxifloxacin 20 mg/mL in a 1:1 mixture of Ora-Plus and Ora-Sweet or Ora-Sweet SF were stable for at least 90 days when stored in 2-oz amber plastic bottles at room temperature.

  15. Preparation of novel alumina nanowire solid-phase microextraction fiber coating for ultra-selective determination of volatile esters and alcohols from complicated food samples.

    PubMed

    Zhang, Zhuomin; Ma, Yunjian; Wang, Qingtang; Chen, An; Pan, Zhuoyan; Li, Gongke

    2013-05-17

    A novel alumina nanowire (ANW) solid-phase microextraction (SPME) fiber coating was prepared by a simple and rapid anodization-chemical etching method for ultra-selective determination of volatile esters and alcohols from complicated food samples. Preparation conditions for ANW SPME fiber coating including corrosion solution concentration and corrosion time were optimized in detail for better surface morphology and higher surface area based on scanning electron microscope (SEM). Under the optimum conditions, homogeneous alumina nanowire structure of ANW SPME fiber coating was achieved with the average thickness of 20 μm around. Compared with most of commercial SPME fiber coatings, ANW SPME fiber coatings achieved the higher extraction capacity and special selectivity for volatile esters and alcohols. Finally, an efficient gas sampling technique based on ANW SPME fiber coating as the core was established and successfully applied for the ultra-selective determination of trace volatile esters and alcohols from complicated banana and fermented glutinous rice samples coupled with gas chromatography/mass spectrometry (GC/MS) detection. It was interesting that 25 esters and 2 alcohols among 30 banana volatile organic compounds (VOCs) identified and 4 esters and 7 alcohols among 13 identified VOCs of fermented glutinous rice were selectively sampled by ANW SPME fiber coatings. Furthermore, new analytical methods for the determination of some typical volatile esters and alcohols from banana and fermented glutinous rice samples at specific storage or brewing phases were developed and validated. Good recoveries for banana and fermented glutinous rice samples were achieved in range of 108-115% with relative standard deviations (RSDs) of 2.6-6.7% and 80.0-91.8% with RSDs of 0.3-1.3% (n=3), respectively. This work proposed a novel and efficient gas sampling technique of ANW SPME which was quite suitable for ultra-selectively sampling trace volatile esters and alcohols from

  16. A quick and effective method of limb preparation with health, safety and efficiency benefits.

    PubMed

    Naderi, N; Maw, K; Thomas, M; Boyce, D E; Shokrollahi, K

    2012-03-01

    Pre-operative limb preparation (PLP) usually involves lifting the limb and holding it in a fixed 'static' posture for several minutes. This is hazardous to theatre staff. Furthermore, 'painting' the limb can be time consuming and difficult areas such as between toes and fingers may remain unsterile. We demonstrate the time efficiency and asepsis achieved using the 'sterile bag' preparation technique. An additional advantage is the ability to prepare and anaesthetise a limb prior to theatre, increasing efficiency substantially for units with a large throughput of cases, such as day-case hand surgery lists. We monitored the duration of PLP in 20 patients using the 'sterile bag' technique compared to 20 patients using a conventional 'painting' method. Additionally, microbiology samples acquired from prepared upper limbs of 27 sequential patients operated on by a single surgeon over a two-month period were sent for culture immediately prior to commencement of surgery. The mean duration of the 'sterile bag' PLP was significantly lower than that of the conventional method (24 seconds vs 85 seconds, p=0.045). The technique can take as little as ten seconds (n=1). Final microbiology reports showed no growth for any of the 27 patients from whom a culture sample was taken. The sterile bag technique is effective in achieving asepsis, has the potential to increase theatre efficiency and reduces manual handling hazards compared to the conventional method. It is now taught to all theatre staff in our hospital during manual handling training. It can be undertaken in approximately ten seconds with practice for the upper limb.

  17. Extemporaneously preparative biodegradable injectable polymer systems exhibiting temperature-responsive irreversible gelation.

    PubMed

    Yoshida, Yasuyuki; Takata, Kazuyuki; Takai, Hiroki; Kawahara, Keisuke; Kuzuya, Akinori; Ohya, Yuichi

    2017-10-01

    On clinical application of biodegradable injectable polymer (IP) systems, quick extemporaneous preparation of IP formulations and longer duration time gel state after injection into the body are the important targets to be developed. Previously, we had reported temperature-responsive covalent gelation systems via bio-orthogonal thiol-ene reaction by 'mixing strategy' of amphiphilic biodegradable tri-block copolymer (tri-PCG) attaching acryloyl groups on both termini (tri-PCG-Acryl) with reactive polythiol. In other previous works, we found 'freeze-dry with PEG/dispersion' method as quick extemporaneous preparation method of biodegradable IP formulations. In this study, we applied this quick preparative method to the temperature-triggered covalent gelation system. The instant formulation (D-sample) could be prepared by 'freeze-dry with PEG/dispersion' just mixing of tri-PCG-Acryl micelle dispersion and tri-PCG/DPMP micelle dispersion with PEG, that can be prepared in 30 s from the dried samples. The obtained D-sample showed irreversible gelation and long duration time of gel state, which was basically the same as the formulations prepared by the usual heating dissolution method (S-sample). Interestingly, the D-sample could maintain its sol state for a longer time (24 h) after preparing the formulation at r.t. compared with the S-sample, which became a gel in 3 h after preparing. The IP system showed good biocompatibility and long duration time of the gel state after subcutaneous implantation. These characteristics of D-samples, quick extemporaneous preparation and high stability in the sol state before injection, would be very convenient in a clinical setting.

  18. The dosimetric properties of phosphate glass systems prepared by different chemical nanomaterials.

    PubMed

    Abdelhalim, Mohamed Anwar K; Al-Shamrani, Bandar Mora

    2016-12-01

    The synthesis and characterization of glass systems were carried out using prepared nanocrystals injected into a glass matrix as a thermoluminescence (TL) activator using the melt-quenching method. Sample 1 was prepared as [40P 2 O 5 50BaO:2.5MgO, 2.5Na 2 O, 5TiO 2 ], sample 2 as [37.5P 2 O 5 37.5CaO:25TiO 2 ] and sample 3 as [50P 2 O 5 -50Li 2 O]. Formation of the synthesized compound was confirmed by studying the X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. An annealing procedure was carried out for 1 h at 400 °C. The glow curve position and shape shifted dramatically and linearly to the higher temperature values on increasing the heating rate. A heating rate of 30 °C/s was the most suitable for obtaining a high TL response. Samples 2 and 3 have the highest TL response, which approached the effective atomic number (Z eff ) of natural bone. The observed TL sensitivity of the prepared samples 2 and 3 is less than that of commercially available 'TLD-200 chips' and LiF:Mg,Ti (TLD-100) phosphor. Sample [37.5P 2 O 5 37.5CaO:25TiO 2 ] would be useful in personal and environmental dosimetry for measuring high doses of gamma radiation. Sample [50P 2 O 5 -50Li 2 O] is a good dosimeter, although it requires the addition of an appropriate transitional metal (activator) to overcome the problem of high fading. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. [Comparison of the Conventional Centrifuged and Filtrated Preparations in Urine Cytology].

    PubMed

    Sekita, Nobuyuki; Shimosakai, Hirofumi; Nishikawa, Rika; Sato, Hiroaki; Kouno, Hiroyoshi; Fujimura, Masaaki; Mikami, Kazuo

    2016-03-01

    The urine cytology test is one of the most important tools for the diagnosis of malignant urinary tract tumors. This test is also of great value for predicting malignancy. However, the sensitivity of this test is not high enough to screen for malignant cells. In our laboratory, we were able to attain a high sensitivity of urine cytology tests after changing the preparation method of urine samples. The differences in the cytodiagnosis between the two methods are discussed here. From January 2012 to June 2013, 2,031 urine samples were prepared using the conventional centrifuge method (C method) ; and from September 2013 to March 2015, 2,453 urine samples were prepared using the filtration method (F method) for the cytology test. When the samples included in category 4 or 5, were defined as cytological positive, the sensitivities of this test with samples prepared using the F method were significantly high compared with samples prepared using the C method (72% vs 28%, p<0.001). The number of cells on the glass slides prepared by the F method was significantly higher than that of the samples prepared by the C method (p<0.001). After introduction of the F method, the number of f alse negative cases was decreased in the urine cytology test because a larger number of cells was seen and easily detected as atypical or malignant epithelial cells. Therefore, this method has a higher sensitivity than the conventional C method as the sensitivity of urine cytology tests relies partially on the number of cells visualized in the prepared samples.

  20. Sample Curation in Support of the OSIRIS-REx Asteroid Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Righter, Kevin; Nakamura-Messenger, Keiko

    2017-01-01

    micron) samples - a size range NASA has not previously worked in such detail; ii) techniques for removal of contact pad material from the spring steel hooks, iii) static electrical effects of dust sized particles during sample handling and curation is likely to be significant, and iv) the TAGSAM head and associated canister hardware will undoubtedly be coated with fine adhering dust grains from Bennu. In the case of collection of a large bulk sample mass, the adhering dust grains may be of lower priority. If a small sample mass is returned, the adhering dust may attain a higher priority, so recovery of adhering dust grains is an additional challenge to consider. In the year leading up to sample return we plan a variety of sample handling rehearsals that will enables the curation team to be prepared for many new aspects posed by this sample suite.

  1. Stability of Drugs of Abuse in Urine Samples at Room Temperature by Use of a Salts Mixture.

    PubMed

    Pellegrini, Manuela; Graziano, Silvia; Mastrobattista, Luisa; Minutillo, Adele; Busardo, Francesco Paolo; Scarsella, Gianfranco

    2017-01-01

    It has long been recognized that ensuring analyte stability is of crucial importance in the use of any quantitative bioanalytical method. As analyses are usually not performed directly after collection of the biological samples, but after these have been processed and stored, it is essential that analyte stability can be maintained at storage conditions to ensure that the obtained concentration results adequately reflect those directly after sampling. The conservation of urine samples in refrigerated/ frozen conditions is strongly recommended; but not always feasible. The aim of this study was to assess the stability of some well-known drugs of abuse methamphetamine (MA), 11-nor-9-carboxy-Δ9- tetrahydrocannabinol (THC-COOH), benzoylecgonine (BE), and morphine (MOR) in urine samples kept at room temperature by adding a salt mixture (sodium citrate, sodium ascorbate, borax). Two different urine samples were prepared with and without salt mixture, stored at room temperature and then analyzed by gas chromatography-mass spectrometry at 0, 1, 7, 15, and 30 days after collection/preparation to look for eventual analyte degradation. Methamphetamine showed no significant changes with respect to the time of collection/ preparation (T0) up to 7 days later (T7), with or without salt mixture addiction. Then a significant degradation occurred in both salted and non salted urine. BE decrease was observed starting from day 1 after sample collection in salted and not salted samples, respectively. Salt addition seemed to reduce at least the initial BE degradation, with a significant difference (p<0.001) at 7 and 15 days of storage. However, the degradation was not more prevented in salted samples at 30 days of storage. A 20% decrease of MOR concentration was observed starting from day 1 after collection/preparation, both in salted and not salted samples with no subsequent decrease. With regard to THCCOOH, a significant decrease was observed starting from 7 days after collection/preparation

  2. Performance evaluation of a high-pressure microwave-assisted flow digestion system for juice and milk sample preparation.

    PubMed

    Marques, Thiago L; Wiltsche, Helmar; Nóbrega, Joaquim A; Winkler, Monika; Knapp, Günter

    2017-07-01

    Acid digestion is usually required for metal determination in food samples. However, this step is usually performed in batch mode which is time consuming, labor intensive, and may lead to sample contamination. Flow digestion can overcome these limitations. In this work, the performance of a high-pressure microwave-assisted flow digestion system with a large volume reactor was evaluated for liquid samples high in sugar and fat (fruit juice and milk). The digestions were carried out in a coiled perfluoroalkoxy (PFA) tube reactor (13.5 mL) installed inside an autoclave pressurized with 40 bar nitrogen. The system was operated at 500 W microwave power and 5.0 mL min -1 carrier flow rate. Digestion conditions were optimized with phenylalanine, as this substance is known to be difficult to digest completely. The combinations of HCl or H 2 O 2 with HNO 3 increased the digestion efficiency of phenylalanine, and the residual carbon content (RCC) was around 50% when 6.0% V/V HCl or H 2 O 2 was used in combination with 32% V/V HNO 3 . Juice samples were digested with 3.7 mol L -1 HNO 3 and 0.3 mol L -1 HCl, and the RCC was 16 and 29% for apple and mango juices, respectively. Concentrated HNO 3 (10.5 mol L -1 ) was successfully applied for digesting milk samples, and the RCCs were 23 and 25% for partially skimmed and whole milk, respectively. Accuracy and precision of the flow digestion procedure were compared with reference digestions using batch mode closed vessel microwave-assisted digestion and no statistically significant differences were encountered at the 95% confidence level. Graphical abstract Application of a high-pressure microwave-assisted flow digestion system for fruit juice and milk sample preparation.

  3. Do centrally pre-prepared solutions achieve more reliable drug concentrations than solutions prepared on the ward?

    PubMed

    Dehmel, Carola; Braune, Stephan A; Kreymann, Georg; Baehr, Michael; Langebrake, Claudia; Hilgarth, Heike; Nierhaus, Axel; Dartsch, Dorothee C; Kluge, Stefan

    2011-08-01

    To compare the concentration conformity of infusion solutions manually prepared on intensive care units (ICU) with solutions from pharmacy-based, automated production. A prospective observational study conducted in a university hospital in Germany. Drug concentrations of 100 standardised infusion solutions manually prepared in the ICU and 100 matching solutions from automated production containing amiodarone, noradrenaline or hydrocortisone were measured by high-performance liquid chromatography analysis. Deviations from stated concentrations were calculated, and the quality of achieved concentration conformity of the two production methods was compared. Actual concentrations of 53% of the manually prepared and 16% of the machine-made solutions deviated by >5% above or below the stated concentration. A deviation of >10% was measured in 22% of the manually prepared samples and in 5% of samples from automated production. Of the manually prepared solutions, 15% deviated by >15% above or below the intended concentration. The mean concentration of the manually prepared solutions was 97.2% (SD 12.7%, range 45-129%) and of the machine-made solutions was 101.1% (SD 4.3%, range 90-114%) of the target concentration (p < 0.01). In this preliminary study, ward-based, manually prepared infusion solutions showed clinically relevant deviations in concentration conformity significantly more often than pharmacy-prepared, machine-made solutions. Centralised, automated preparation of standardised infusion solutions may be an effective means to reduce this type of medication error. Further confirmatory studies in larger settings and under conditions of routine automated production are required.

  4. [Ultra-Fine Pressed Powder Pellet Sample Preparation XRF Determination of Multi-Elements and Carbon Dioxide in Carbonate].

    PubMed

    Li, Xiao-li; An, Shu-qing; Xu, Tie-min; Liu, Yi-bo; Zhang, Li-juan; Zeng, Jiang-ping; Wang, Na

    2015-06-01

    The main analysis error of pressed powder pellet of carbonate comes from particle-size effect and mineral effect. So in the article in order to eliminate the particle-size effect, the ultrafine pressed powder pellet sample preparation is used to the determination of multi-elements and carbon-dioxide in carbonate. To prepare the ultrafine powder the FRITSCH planetary Micro Mill machine and tungsten carbide media is utilized. To conquer the conglomeration during the process of grinding, the wet grinding is preferred. The surface morphology of the pellet is more smooth and neat, the Compton scatter effect is reduced with the decrease in particle size. The intensity of the spectral line is varied with the change of the particle size, generally the intensity of the spectral line is increased with the decrease in the particle size. But when the particle size of more than one component of the material is decreased, the intensity of the spectral line may increase for S, Si, Mg, or decrease for Ca, Al, Ti, K, which depend on the respective mass absorption coefficient . The change of the composition of the phase with milling is also researched. The incident depth of respective element is given from theoretical calculation. When the sample is grounded to the particle size of less than the penetration depth of all the analyte, the effect of the particle size on the intensity of the spectral line is much reduced. In the experiment, when grounded the sample to less than 8 μm(d95), the particle-size effect is much eliminated, with the correction method of theoretical α coefficient and the empirical coefficient, 14 major, minor and trace element in the carbonate can be determined accurately. And the precision of the method is much improved with RSD < 2%, except Na2O. Carbon is ultra-light element, the fluorescence yield is low and the interference is serious. With the manual multi-layer crystal PX4, coarse collimator, empirical correction, X-ray spectrometer can be used to

  5. A high-throughput semi-automated preparation for filtered synaptoneurosomes.

    PubMed

    Murphy, Kathryn M; Balsor, Justin; Beshara, Simon; Siu, Caitlin; Pinto, Joshua G A

    2014-09-30

    Synaptoneurosomes have become an important tool for studying synaptic proteins. The filtered synaptoneurosomes preparation originally developed by Hollingsworth et al. (1985) is widely used and is an easy method to prepare synaptoneurosomes. The hand processing steps in that preparation, however, are labor intensive and have become a bottleneck for current proteomic studies using synaptoneurosomes. For this reason, we developed new steps for tissue homogenization and filtration that transform the preparation of synaptoneurosomes to a high-throughput, semi-automated process. We implemented a standardized protocol with easy to follow steps for homogenizing multiple samples simultaneously using a FastPrep tissue homogenizer (MP Biomedicals, LLC) and then filtering all of the samples in centrifugal filter units (EMD Millipore, Corp). The new steps dramatically reduce the time to prepare synaptoneurosomes from hours to minutes, increase sample recovery, and nearly double enrichment for synaptic proteins. These steps are also compatible with biosafety requirements for working with pathogen infected brain tissue. The new high-throughput semi-automated steps to prepare synaptoneurosomes are timely technical advances for studies of low abundance synaptic proteins in valuable tissue samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Picosecond laser micromachining prior to FIB milling for electronic microscopy sample preparation

    NASA Astrophysics Data System (ADS)

    Sikora, Aurélien; Fares, Lahouari; Adrian, Jérôme; Goubier, Vincent; Delobbe, Anne; Corbin, Antoine; Sentis, Marc; Sarnet, Thierry

    2017-10-01

    In order to check the manufacturing quality of electronic components using electron microscopy, the area of interest must be exposed. This requires the removal of a large quantity of matter without damaging the surrounding area. This step can be accomplished using ion milling but the processing can last a few hours. In order to accelerate the preparation of the samples, picosecond laser micromachining prior to Focused Ion Beam polishing is envisioned. Laser ablation allows the fast removal of matter but induces damages around the ablated area. Therefore the process has to be optimized in order to limit the size of both the heat affected zone and induced dislocation zone. For this purpose, cavities have been engraved in silicon and in electronic components, using a linearly polarized picosecond laser (∼50 ps) at three different wavelengths (343, 515 and 1030 nm). Results showed that the cross sectional shapes and the surface topologies can be tuned by the laser fluence and the number of pulses. Clear cross sections of bumps and cavity openings, exposing multilayer interfaces, are demonstrated. The silicon removal rates, tuned by the applied energy density, have been measured. Removal rates achieved at 200 kHz were typically hundred times higher than those achieved by ion milling and the best efficiency was obtained at 343 nm.

  7. A simple preparation of graphite/gelatin composite for electrochemical detection of dopamine.

    PubMed

    Rajkumar, Chellakannu; Thirumalraj, Balamurugan; Chen, Shen-Ming; Chen, His-An

    2017-02-01

    In this study, we demonstrate a simple preparation of graphite (GR) sheets assisted with gelatin (GLN) polypeptide composite was developed for sensitive detection of dopamine (DA) sensor. The GR/GLN composite was prepared by GR powder in GLN solution (5mg/mL) via sonication process. The prepared GR/GLN composite displays well dispersion ability in biopolymer matrix and characterized via scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) studies. The GR/GLN modified electrode showed an excellent electrocatalytic activity toward the oxidation of DA, suggesting that the successful formation of GR sheets crosslinked with the functional groups of GLN polypeptide. In addition, the GR/GLN modified electrode achieved a wide linear response ranging from 0.05 to 79.5μM with a detection limit of 0.0045μM. The calculated analytical sensitivity of the sensor was 1.36±0.02μAμM -1 cm -2 . Conversely, the modified electrode demonstrates a good storage stability, reproducibility and repeatability. In addition, the sensor manifests the determination of DA in human serum and urine samples for practical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Dried Blood Spot Proteomics: Surface Extraction of Endogenous Proteins Coupled with Automated Sample Preparation and Mass Spectrometry Analysis

    NASA Astrophysics Data System (ADS)

    Martin, Nicholas J.; Bunch, Josephine; Cooper, Helen J.

    2013-08-01

    Dried blood spots offer many advantages as a sample format including ease and safety of transport and handling. To date, the majority of mass spectrometry analyses of dried blood spots have focused on small molecules or hemoglobin. However, dried blood spots are a potentially rich source of protein biomarkers, an area that has been overlooked. To address this issue, we have applied an untargeted bottom-up proteomics approach to the analysis of dried blood spots. We present an automated and integrated method for extraction of endogenous proteins from the surface of dried blood spots and sample preparation via trypsin digestion by use of the Advion Biosciences Triversa Nanomate robotic platform. Liquid chromatography tandem mass spectrometry of the resulting digests enabled identification of 120 proteins from a single dried blood spot. The proteins identified cross a concentration range of four orders of magnitude. The method is evaluated and the results discussed in terms of the proteins identified and their potential use as biomarkers in screening programs.

  9. Applications of derivatization reactions to trace organic compounds during sample preparation based on pressurized liquid extraction.

    PubMed

    Carro, Antonia M; González, Paula; Lorenzo, Rosa A

    2013-06-28

    Pressurized liquid extraction (PLE) is an exhaustive technique used for the extraction of analytes from solid samples. Temperature, pressure, solvent type and volume, and the addition of other reagents notably influence the efficiency of the extraction. The analytical applications of this technique can be improved by coupling with appropriate derivatization reactions. The aim of this review is to discuss the recent applications of the sequential combination of PLE with derivatization and the approaches that involve simultaneous extraction and in situ derivatization. The potential of the latest developments to the trace analysis of environmental, food and biological samples is also analyzed. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Effect of preparation methods and doping on the structural and tunable emissions of CdS

    NASA Astrophysics Data System (ADS)

    Mohamed, Mohamed Bakr; Abdel-Kader, M. H.; Alhazime, Ali A.; Almarashi, Jamal Q. M.

    2018-03-01

    Fe, Mn and Mg doped CdS samples were prepared by thermolysis method in air and under flow of nitrogen. Structural, compositional and optical properties of the prepared samples were investigated using x-ray powder diffraction (XRD), scanning electron microscope (SEM/EDS mapping), Fourier transform infrared red (FTIR), UV-vis absorption and photoluminescence (PL) spectroscopes. Rietveld refinement of x-ray data showed that all the undoped and doped CdS samples prepared in air and under flow of nitrogen have both cubic and hexagonal structures. The percentages of hexagonal and cubic phases for all prepared samples were determined. The crystallite size increased for CdS prepared under flow of N2 compared with the sample prepared in air. The energy gap of all the samples was calculated using UV data. The intensity of PL emission changed according to the method of preparation and the kind of doping elements. PL emission revealed a blue shift for CdS prepared in air compared with CdS prepared under flow of nitrogen; also all doped samples showed a red shift of PL spectra compared with undoped samples. Undoped and doped CdS with Fe and Mg samples emitted violet and blue sub-spectra. Mn doped CdS prepared in air revealed violet, blue and yellow sub-spectra, while the sample prepared under flow of N2 emitted violet, blue and green sub-spectra.

  11. Preparation of solid-phase microextraction fibers by in-mold coating strategy for derivatization analysis of 24-epibrassinolide in pollen samples.

    PubMed

    Pan, Jialiang; Hu, Yuling; Liang, Tingan; Li, Gongke

    2012-11-02

    A novel and simple in-mold coating strategy was proposed for the preparation of uniform solid-phase microextraction (SPME) coatings. Such a strategy is based on the direct synthesis of the polymer coating on the surface of a solid fiber using a glass capillary as the mold. The capillary was removed and the polymer with well-controlled thickness could be coated on the silica fiber reproductively. Following the strategy, a new poly(acrylamide-co-ethylene glycol dimethacrylate) (poly(AM-co-EGDMA)) coating was prepared for the preconcentration of 24-epibrassinolide (24-epiBL) from plant matrix. The coating had the enrichment factor of 32 folds, and the extraction efficiency per unit thickness was 5 times higher than that of the commercial polydimethylsiloxane/divinylbenzene (PDMS/DVB) coating. A novel method based on SPME coupled with derivatization and large volume injection-high performance liquid chromatography (LVI-HPLC) was developed for the analysis of 24-epiBL. The linear range was 0.500-20.0 μg/L with the detection limit of 0.13 μg/L. The amounts of endogenous 24-epiBL in rape and sunflower breaking-wall pollens samples were determined with satisfactory recovery (77.8-104%) and reproducibility (3.9-7.9%). The SPME-DE/LVI-HPLC method is rapid, reliable, convenient and applicable for complicated plant samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Non-Contact Conductivity Measurement for Automated Sample Processing Systems

    NASA Technical Reports Server (NTRS)

    Beegle, Luther W.; Kirby, James P.

    2012-01-01

    A new method has been developed for monitoring and control of automated sample processing and preparation especially focusing on desalting of samples before analytical analysis (described in more detail in Automated Desalting Apparatus, (NPO-45428), NASA Tech Briefs, Vol. 34, No. 8 (August 2010), page 44). The use of non-contact conductivity probes, one at the inlet and one at the outlet of the solid phase sample preparation media, allows monitoring of the process, and acts as a trigger for the start of the next step in the sequence (see figure). At each step of the muti-step process, the system is flushed with low-conductivity water, which sets the system back to an overall low-conductivity state. This measurement then triggers the next stage of sample processing protocols, and greatly minimizes use of consumables. In the case of amino acid sample preparation for desalting, the conductivity measurement will define three key conditions for the sample preparation process. First, when the system is neutralized (low conductivity, by washing with excess de-ionized water); second, when the system is acidified, by washing with a strong acid (high conductivity); and third, when the system is at a basic condition of high pH (high conductivity). Taken together, this non-contact conductivity measurement for monitoring sample preparation will not only facilitate automation of the sample preparation and processing, but will also act as a way to optimize the operational time and use of consumables

  13. NH4NO3 extractable trace element contents of soil samples prepared for proficiency testing--a stability study.

    PubMed

    Traub, H; Scharf, H

    2001-06-01

    In view of its intended use as a sample for proficiency testing or as a reference material the stability of the extractable trace element contents of a soil from an irrigation field was tested using the extraction with 1 mol/L ammonium nitrate solution according to DIN 19730. Therefore, changes of the extractability of sterilized and non sterilized soil samples stored at different temperatures were evaluated over a period of 18 months. Sets of bottles were kept at -20 degrees C, +4 degrees C, about +20 degrees C and +40 degrees C, respectively. The NH4NO3 extractable contents of Cd, Cr, Cu, Ni, Pb and Zn were determined immediately after bottling and then after 3, 6, 12 and 18 months with ICP-AES or ETAAS. Appropriate storage conditions are of utmost importance to prevent deterioration of soil samples prepared for the determination of NH4NO3 extractable trace element contents. Temperatures above +20 degrees C must be avoided. The observed changes in the extractability of the metals (especially for Cr and Cu) most likely could be related to thermal degradation of the organic matter of the soil. There is no need to sterilize dry soil samples, because microbiological activity in soils with a low moisture content appears to be negligible with regard to trace element mobilization.

  14. Stability of extemporaneously prepared rifaximin oral suspensions.

    PubMed

    Cober, Mary Petrea; Johnson, Cary E; Lee, Jordan; Currie, Kenne

    2010-02-15

    The stability of extemporaneously prepared rifaximin oral suspensions was studied. An oral suspension of rifaximin 20 mg/mL was prepared by thoroughly grinding six 200-mg tablets of rifaximin in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of either Ora-Sweet or Ora-Sweet SF were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of each formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and were stored at room temperature (23-25 degrees C). A 1-mL sample was withdrawn from each of the six bottles with a micropipette immediately after preparation and at 7, 15, 30, and 60 days. After further dilution to an expected concentration of 20 microg/mL with mobile phase, the samples were assayed in duplicate using stability-indicating high-performance liquid chromatography. The samples were visually examined for any color change and pH was tested on each day of analysis. Stability was determined by evaluating the percentage of the initial concentration remaining at each time point and defined as retention of at least 90% of the initial concentration of rifaximin. At least 99% of the initial rifaximin remained throughout the 60-day study period in both preparations. There were no detectable changes in color, odor, taste, or pH and no visible microbial growth in any sample. Extemporaneously prepared suspensions of rifaximin 20 mg/mL in 1:1 mixtures of Ora-Plus with either Ora-Sweet or Ora-Sweet SF were stable for at least 60 days when stored in 2-oz amber plastic bottles at room temperature.

  15. Preview of the NASA NNWG NDE Sample Preparation Handbook

    NASA Technical Reports Server (NTRS)

    2010-01-01

    This viewgraph presents a step-by-step how-to fabrication documentation of every kind of sample that is fabricated for MSFC by UA Huntsville, including photos and illustrations. The tabulation of what kind of samples are being fabricated for what NDE method, detailed instructions/documentation of the inclusion/creation of defects, detailed specifications for materials, processes, and equipment, case histories and/or experiences with the different fabrication methods and defect inclusion techniques, discussion of pitfalls and difficulties associated with sample fabrication and defect inclusion techniques, and a discussion of why certain fabrication techniques are needed as related to the specific NDE methods are included in this presentation.

  16. Sample introducing apparatus and sample modules for mass spectrometer

    DOEpatents

    Thompson, Cyril V.; Wise, Marcus B.

    1993-01-01

    An apparatus for introducing gaseous samples from a wide range of environmental matrices into a mass spectrometer for analysis of the samples is described. Several sample preparing modules including a real-time air monitoring module, a soil/liquid purge module, and a thermal desorption module are individually and rapidly attachable to the sample introducing apparatus for supplying gaseous samples to the mass spectrometer. The sample-introducing apparatus uses a capillary column for conveying the gaseous samples into the mass spectrometer and is provided with an open/split interface in communication with the capillary and a sample archiving port through which at least about 90 percent of the gaseous sample in a mixture with an inert gas that was introduced into the sample introducing apparatus is separated from a minor portion of the mixture entering the capillary discharged from the sample introducing apparatus.

  17. Stability of oseltamivir in various extemporaneous liquid preparations.

    PubMed

    Ford, Stephen M; Kloesel, Lawson G; Grabenstein, John D

    2007-01-01

    The purpose of this study was to determine the stability of oseltamivir, the active ingredient in Tamiflu, in contemporaneously compounded suspensions for a period of not less than 90 days. The suspension vehicles provided for the study were chosen because of ease of preparation, commercial availability, and palatability. Stability of the active ingredient was demonstrated for suspensions prepared in PCCA-Plus, PCCA Acacia, and 1% methylcellulose and was independent of storage temperature (tested temperatures were 2 deg C to 8 deg C and 25 deg C). A control sample of the commercial liquid form of Tamiflu was prepared, stored and analyzed along with the samples prepared from the contents of capsules. There was no difference in the apparent stability of the two forms of the drug preparation.

  18. A novel sample preparation procedure for effect-directed analysis of micro-contaminants of emerging concern in surface waters.

    PubMed

    Osorio, Victoria; Schriks, Merijn; Vughs, Dennis; de Voogt, Pim; Kolkman, Annemieke

    2018-08-15

    A novel sample preparation procedure relying on Solid Phase Extraction (SPE) combining different sorbent materials on a sequential-based cartridge was optimized and validated for the enrichment of 117 widely diverse contaminants of emerging concern (CECs) from surface waters (SW) and further combined chemical and biological analysis on subsequent extracts. A liquid chromatography coupled to high resolution tandem mass spectrometry LC-(HR)MS/MS protocol was optimized and validated for the quantitative analysis of organic CECs in SW extracts. A battery of in vitro CALUX bioassays for the assessment of endocrine, metabolic and genotoxic interference and oxidative stress were performed on the same SW extracts. Satisfactory recoveries ([70-130]%) and precision (< 30%) were obtained for the majority of compounds tested. Internal standard calibration curves used for quantification of CECs, achieved the linearity criteria (r 2 > 0.99) over three orders of magnitude. Instrumental limits of detection and method limits of quantification were of [1-96] pg injected and [0.1-58] ng/L, respectively; while corresponding intra-day and inter-day precision did not exceed 11% and 20%. The developed procedure was successfully applied for the combined chemical and toxicological assessment of SW intended for drinking water supply. Levels of compounds varied from < 10 ng/L to < 500 ng/L. Endocrine (i.e. estrogenic and anti-androgenic) and metabolic interference responses were observed. Given the demonstrated reliability of the validated sample preparation method, the authors propose its integration in an effect-directed analysis procedure for a proper evaluation of SW quality and hazard assessment of CECs. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Ureilite Thin Section Preparation

    NASA Technical Reports Server (NTRS)

    Harrington, R.; Righter, K.

    2014-01-01

    Preparing thin and thick sections of ureilite type meteorites is a challenge that can confound even the most experienced section preparer. A common characteristic of these samples is the presence of carbon phases, particularly nanodiamonds, in the matrix along silicate grain boundaries, fractures, and cleavage plains [1]. The extreme hardness of the nanodiamonds presents a challenge to the section preparer in the form of high surface relief on the section. This hard material also causes considerable wear and tear on equipment and materials that are used for making the sections. These issues will be discussed and potentially helpful measures will be presented.

  20. Quantification of tamoxifen DNA adducts using on-line sample preparation and HPLC-electrospray ionization tandem mass spectrometry.

    PubMed

    Gamboa da Costa, Gonçalo; Marques, M Matilde; Beland, Frederick A; Freeman, James P; Churchwell, Mona I; Doerge, Daniel R

    2003-03-01

    The nonsteroidal antiestrogen tamoxifen is used as an adjuvant chemotherapeutic agent for the treatment of all stages of hormone-dependent breast cancer and more recently as a chemopreventive agent in women with elevated risk of developing the disease. While clearly beneficial for the treatment of breast cancer, tamoxifen has been reported to increase the risk of endometrial cancer in women. Furthermore, it has been shown to be hepatocarcinogenic in rats. Tamoxifen is clearly genotoxic in rat liver, as indicated by the formation of DNA adducts; the occurrence of tamoxifen DNA adducts in human endometrial tissue is more controversial. The detection and quantitation of tamoxifen DNA adducts have relied primarily upon (32)P-postlabeling, with other techniques, such as immunoassays and accelerator mass spectrometry, being used to a much lesser extent. To expand the range of available analytical methodologies for quantifying tamoxifen DNA adducts, we have developed an assay using on-line sample preparation, coupled with HPLC and electrospray ionization tandem mass spectrometry (ES-MS/MS). alpha-Acetoxytamoxifen was reacted with salmon testis DNA at ratios between 0.1 ng and 1 mg alpha-acetoxytamoxifen per mg DNA. After enzymatic hydrolysis to nucleosides, the most highly modified DNA samples were analyzed by HPLC-UV, which indicated the presence of two adduct peaks in approximately a 1:4 ratio. The major adduct was isolated, rigorously characterized as (E)-alpha-(deoxyguanosin-N(2)-yl)tamoxifen, and quantified on the basis of its molar extinction coefficient. A similar reaction was conducted with [N(CD(3))(2)]-alpha-acetoxytamoxifen to prepare a deuterated adduct that could serve as an internal standard for ES-MS/MS. The limit of detection for the HPLC-ES-MS/MS method was approximately 5 adducts/10(9) nucleotides, with an intra- and interassay precision of 3% relative standard deviation. The method was validated over the range of 8-1 520,000 adducts/10(8) nucleotides