Improved Negative Stain Electron Microscopy Procedure for Detecting Surface Detail On
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Uranium-Free X Solution
www.nature.com/scientificreports OPEN Uranium‑free X solution: a new generation contrast agent for biological samples ultrastructure Aldo Moscardini1,6, Sebastiano Di Pietro 2,6, Giovanni Signore3*, Paola Parlanti4, Melissa Santi5, Mauro Gemmi5 & Valentina Cappello5* Biological samples are mainly composed of elements with a low atomic number which show a relatively low electron scattering power. For Transmission Electron Microscopy analysis, biological samples are generally embedded in resins, which allow thin sectioning of the specimen. Embedding resins are also composed by light atoms, thus the contrast diference between the biological sample and the surrounding resin is minimal. Due to that reason in the last decades, several staining solutions and approaches, performed with heavy metal salts, have been developed with the purpose of enhancing both the intrinsic sample contrast and the diferences between the sample and resin. The best staining was achieved with the uranyl acetate (UA) solution, which has been the election method for the study of morphology in biological samples. More recently several alternatives for UA have been proposed to get rid of its radiogenic issues, but to date none of these solutions has achieved efciencies comparable to UA. In this work, we propose a diferent staining solution (X Solution or X SOL), characterized by lanthanide polyoxometalates (LnPOMs) as heavy atoms source, which could be used alternatively to UA in negative staining (NS), in en bloc staining, and post sectioning staining (PSS) of biological samples. Furthermore, we show an extensive chemical characterization of the LnPOM species present in the solution and the detailed work for its fnal formulation, which brought remarkable results, and even better performances than UA. -
Negative Stain Grid Preparation
Negative Stain Grid Preparation Generic Protocol for Single Particle – Page 2 Example For Bacteria – Page 5 Example For Viruses – Page 6 Example For Purified Bacterial Flagella – Page 7 Drafted by E. Montemayor, 6/15/2020. Revisions by EJM, JCS, ERW, 1/6/2021 1 Generic protocol for negative stain grid preparation Think of this as a “try this first” pipeline for new samples. Sample concentration and type of stain tend to be the most important variables, then additives like detergents or crosslinking should be tried next. Overview at a glance: Step 1: Prepare serial four-fold dilutions of your sample, covering at least two order of magnitude in sample concentration. Typical ceiling for sample concentration is ~ 1 mg/mL. Step 2: Prepare negative stain solution. Uranyl stains are most popular as a first pass, especially for single particle work. Consider filtering (0.1 µm or 0.2 µm syringe filters) and centrifuging (5-15 min, 15,000 rpm, and at room temperature (RT)) your stain to reduce crystals and debris. Step 3: Glow discharge grids. Standard thickness carbon on a 200 copper mesh is a popular support. Step 4: Place grid in self closing tweezers. Use a microscope or magnifying lens to help you touch only the edge of the grid with the tweezers. Step 5: Set up 2x 20 µL drops of buffer and 3x 20 µL drops of stain on a strip of parafilm. Apply 3 µL of sample to carbon side of grid and incubate for 1 minute. Step 6: Side blot to remove sample but do not let grid dry out. -
Synthesis and Characterization of Novel Hybrid Polysulfone/Silica Membranes Doped with Phosphomolybdic Acid for Fuel Cell Applications
This is a postprint version of the following published document: M.J. Martínez-Morlanes, A.M. Martos, A. Várez, B. Levenfeld. Synthesis and characterization of novel hybrid polysulfone/silica membranes doped with phosphomolybdic acid for fuel cell applications. Journal of Membrane Science, 492 (2015) , pp 371–379 © 2015 Elsevier B.V. All rights reserved. DOI: 10.1016/j.memsci.2015.05.031 Synthesis and characterization of novel hybrid polysulfone/silica membranes doped with phosphomolybdic acid for fuel cell applications M.J. Martínez-Morlanes n, A.M. Martos, A. Várez, B. Levenfeld Department of Materials Science and Engineering and Chemical Engineering, Universidad Carlos III de Madrid, Avda. Universidad, 30, E-28911 Leganés, Spain abstract Novel proton conducting composite membranes based on sulfonated polysulfone (sPSU)/SiO2 doped with phosphomolybdic acid (PMoA) were synthesized, and their proton conductivity in acid solutions was evaluated. The hybrid membranes were prepared by casting and the characterization by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X ray diffraction (XRD) confirmed the presence of the inorganic charges into the polymer. Thermal properties and proton conductivity were also studied by means of thermogravimetric analysis (TGA) and electrochemical impedance spectro Keywords: scopy (EIS), respectively. The incorporation of the inorganic particles modified the thermal and Proton-exchange membrane fuel cell mechanical properties of the sPSU as well as its proton conductivity. Taking into account that a Polysulfone compromise between these properties is necessary, the hybrid membrane with 2%SiO2 and 20%PMoA Silicon oxide seems to be a promising candidate for its application in proton exchange membrane in fuel cells Heteropolyacid (PEMFCs) operated at high temperatures. -
Electron Microscopy of Negatively Stained and Unstained Fibrinogen (Scanning Transmission Electron Microscopy) LEONARD F
Proc. Natl. Acad. Sci. USA Vol. 77, No. 6, pp. 3139-3143, June 1980 Biochemistry Electron microscopy of negatively stained and unstained fibrinogen (scanning transmission electron microscopy) LEONARD F. ESTIS* AND RUDY H. HASCHEMEYER Department of Biochemistry, Cornell University Medical College, 1300 York Avenue, New York, New York 10021 Communicated by Alton Meister, December 26,1979 ABSTRACT Electron microscopic images of negatively are always met: (i) The great majority of images of "apparent stained fibrinogen are predominantly asymmetric rods 450 A particles" in any field are of fibrinogen molecules. (Ui) The in length and about 60 A in width. The molecules appear to have considerable flexibility, and mass distribution along the major number of identifiable fibrinogen molecules is defined by fi- axis is not uniquely distinguished despite apparent beading in brinogen concentration and application time and not by the some particles. Scanning transmission electron microscopy of buffer, pH, or staining conditions. (Mii) Large-field views of unstained fibrinogen again demonstrates that a majority of fibrinogen contain predominantly well-separated molecules molecules are rodlike. The results differ from those obtained with clearly defined morphology and dimensions. by negative staining in that a substantial fraction of images are Conditions trinodular with striking resemblance to those obtained by C. required to achieve these goals are primarily E. Hall and H. S. Slayter IJ Biophys. Bioehem. Cytol. (1959) 5, related to attachment of fibrinogen to the substrate film. Once 11-161 using the mica replictecaique. The above results were this problem was solved, images of the unstained molecule were obtained on glow-discharged carbon substrate films by a simple also obtained by high-resolution scanning transmission electron low-concentration, lon&-attachment-time modification of microscopy (STEM). -
Total Phenolic Contents and Antioxidant Capacities of Selected Chinese Medicinal Plants
Int. J. Mol. Sci. 2010, 11, 2362-2372; doi:10.3390/ijms11062362 OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 www.mdpi.com/journal/ijms Article Total Phenolic Contents and Antioxidant Capacities of Selected Chinese Medicinal Plants Feng-Lin Song, Ren-You Gan, Yuan Zhang, Qin Xiao, Lei Kuang and Hua-Bin Li * Department of Nutrition, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China; E-Mails: [email protected] (F.-L.S.); [email protected] (R.-Y.G.); [email protected] (Y.Z.); [email protected] (Q.X.); [email protected] (L.K.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +86-20-8733-2391; Fax: +86-20-8733-0446. Received: 14 April 2010 / Accepted: 21 May 2010 / Published: 1 June 2010 Abstract: Antioxidant capacities of 56 selected Chinese medicinal plants were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) assays, and their total phenolic content was measured by the Folin-Ciocalteu method. The strong correlation between TEAC value and FRAP value suggested that the antioxidants in these plants possess free radical scavenging activity and oxidant reducing power, and the high positive correlation between antioxidant capacities and total phenolic content implied that phenolic compounds are a major contributor to the antioxidant activity of these plants. The results showed that Dioscorea bulbifera, Eriobotrya japonica, Tussilago farfara and Ephedra sinica could be potential rich sources of natural antioxidants. Keywords: medicinal plant; phenolic content; antioxidant capacity 1. Introduction Free radicals are produced as a part of normal metabolic processes. -
CHARACTERIZING and MANIPULATING BIOLOGICAL INTERACTIONS of VIRUSES by NEETU MEHEK GULATI Submitted in Partial Fulfillment Of
CHARACTERIZING AND MANIPULATING BIOLOGICAL INTERACTIONS OF VIRUSES by NEETU MEHEK GULATI Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Advisors: Dr. Phoebe L. Stewart and Dr. Nicole F. Steinmetz Department of Pharmacology CASE WESTERN RESERVE UNIVERSITY January 2018 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of Neetu Mehek Gulati candidate for the Doctor of Philosophy degree*. (signed) Vera Moiseenkova-Bell (chair of the committee) Phoebe L. Stewart Nicole F. Steinmetz Derek J. Taylor Jun Qin Vivien C. Yee (date) September 8, 2017 *We also certify that written approval has been obtained for any proprietary material contained therein. Table of Contents List of Tables ..................................................................................................... vii List of Figures .................................................................................................. viii Acknowledgements ........................................................................................... xi List of Abbreviations ....................................................................................... xiv Abstract ............................................................................................................ xxi Chapter 1: Introduction ...................................................................................... 1 1.1 Viruses – for good and bad ................................................................ -
Encapsulation of Keggin-Type Phosphotungstic Acid Into the Mesopores of SBA-16 As a Reusable Heterogeneous Catalyst for the Epoxidation of Ole Ns
Scientia Iranica C (2017) 24(6), 2993{3001 Sharif University of Technology Scientia Iranica Transactions C: Chemistry and Chemical Engineering www.scientiairanica.com Encapsulation of Keggin-type phosphotungstic acid into the mesopores of SBA-16 as a reusable heterogeneous catalyst for the epoxidation of ole ns M. Masteri-Farahani and M. Modarres Faculty of Chemistry, Kharazmi University, Tehran, Iran. Received 28 February 2016; received in revised form 3 March 2017; accepted 18 September 2017 KEYWORDS Abstract. A heterogeneous catalyst for the epoxidation of ole ns was prepared by encap- sulating Keggin-type phosphotungstic acid (H PW O ) into the mesopores of SBA-16. Mesoporous SBA-16; 3 12 40 After the encapsulation, the pore entrance size of SBA-16 was reduced through a silylation Heteropoly acid; method to encompass the catalyst in the mesopores and allow easy di usion of the reactants Keggin; and products during the catalytic process. The prepared catalyst was characterized by FT- Immobilization; IR and Inductively Coupled Plasma-Optical Emission Spectroscopies(ICP-OES), X-Ray Epoxidation. Di raction (XRD), and Transmission Electron Microscopy (TEM). The analysis results revealed that the mesoporous nature of SBA-16 was conserved after encapsulation of the catalyst following the silylation step. The catalytic activity of the prepared material was assessed in the epoxidation of ole ns with H2O2. The heterogeneous catalyst was recovered and reused up to ve cycles without considerable decrease in activity. © 2017 Sharif University of Technology. All rights reserved. 1. Introduction ole ns in the presence of hydrogen peroxide [15-18]. However, the troubles in separation and reuse of these Polyoxometalates (POMs) are a prominent category homogeneous catalysts have restricted their large-scale of transition metal oxide anions, mostly vanadium, applications in industrial syntheses. -
Immunoelectron Microscopy for Virus Identification
Chapter 7 ROBERT G. MILNE Immunoelectron Microscopy for Virus Identification 1 Introduction I am going to discuss immunonegative staining-the immunoelectron microscopy (!EM) of virus (or other pathogen-related) particles in suspension-with only short excursions into the topic of immune reactions on or in thin sections, as these are considered elsewhere in this book. As the field has been thoroughly reviewed, what I shall say will be more an informal commentary than an exhaustive survey, and I shall not necessarily follow each statement by a precise citation, or attempt to mention all the interesting papers. In places I shall use the term "grid" to mean support film. As all those know, who have worked with viruses both in negative stain and in thin sections, resolution is much higher in negative stain, and intensity and fidelity of immunolabeling is also greater; you would never work with sections again if they did not furnish positional information that is lost when you make an extract. This loss means that in negative stain you can only work with structures that can be recognizcd out of context-virus particles, subviral components, or certain virus induced inclusions; perhaps also mycoplasmas or their fragments. However, sometimes the same structures can be recognized both in vitro and in situ; and with the advantage of immune labeling we can, with luck, identify an antigen in both contexts. In that case we can obtain both positional or contextual information as well as high-resolution details of structure or antigen location. An interesting technique that I will not discuss, but which may prove a valuable compromise, is immunonegative staining of thin cryosections. -
University of Southampton Research Repository Eprints Soton
University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk UNIVERSITY OF SOUTHAMPTON Faculty of Engineering and the Environment Energy Technology Research group Heteropolyacids and non-carbon electrode materials for fuel cell and battery applications by Maria Kourasi Thesis for the degree of Doctor of Philosophy February 2015 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF ENGINEERING AND THE ENVIRONMENT Doctor of Philosophy HETEROPOLYACIDS AND NON-CARBON ELECTRODE MATERIALS FOR FUEL CELL AND BATTERY APPLICATIONS by Maria Kourasi Heteropolyacids (HPAs) are a group of chemicals that have shown promising results as catalysts during the last decades. Since HPAs have displayed encouraging performance as electrocatalysts in acidic environment, in this project their redox activity in acid and alkaline aqueous electrolytes and their electrocatalytic performance as additives on a bifunctional gas diffusion electrode in alkaline aqueous electrolyte are tested. -
United States Patent (19) 11 Patent Number: 4,965,236 Roberts 45 Date of Patent: Oct
United States Patent (19) 11 Patent Number: 4,965,236 Roberts 45 Date of Patent: Oct. 23, 1990 (54) PROCESS FOR PRODUCING A CATALYST 3,867,312 2/1975 Stephens ............................. 252/462 4,019,978 4/1977 Miller et al. ........................ 208/213 75 Inventor: John S. Roberts, Bartlesville, Okla. 4,059,636 11/1977 Kubicek. ... 260/609 D 4,066,572 1/1978 Choca ................................. 252/437 (73) Assignee: Phillips Petroleum Company, 4,080,311 3/1978 Kehl. ... 252/437 Bartlesville, Okla. 4,145,352 3/1979 Kubicek ... ... 260/326.82 4,146,574 3/1979 Onoda et al. ....................... 423/299 21) Appl. No.: 335,651 4,297,242 10/1981 Hensley, Jr. et al. ... 252/439 22 Fied: Apr. 10, 1989 4,444,906 4/1984 Callahan et al. ......... ... 502/211 4,522,934 6/1985 Shum et al.......................... 502/209 Related U.S. Application Data Primary Examiner-W. J. Shine 60 Division of Ser. No. 908,558, Sep. 18, 1986, Pat. No. Attorney, Agent, or Firm-J. D. Brown 4,837,192, which is a continuation-in-part of Ser. No. 742,818, Jun. 10, 1985, abandoned, which is a division 57 ABSTRACT of Ser. No. 542,960, Oct. 18, 1983, Pat. No. 4,537,994. Interchange reactions between organosulfides and ner (51) Int. Cl. ......................... B01J 27/18; B01J 27/19 captans are promoted by the use of catalysts containing (52) U.S. C. .................................................... 502/211 Group VIB oxides. The preferred catalysts are sup Field of Search ................................ 502/210, 211 ported phospho Group VIB oxide acids, such as phos (58 photungstic acid and phosphomolybdic acid. -
Hematoxylin P.T.A
HEMATOXYLIN P.T.A. IVD In vitro diagnostic medical device Synonims: Hematoxylin Phospotungstic Acid, Mallory P.T.A.H. reagent INSTRUCTIONS FOR USE REF Catalogue number: HPTA-OT-500 (500 mL) HPTA-OT-1L (1000 mL) Introduction Hematoxylin P.T.A. reagent is used for staining collagen, muscle tissue (excellent diferentiation between smooth and striated muscle tissue), Nemaline rods (present in certain skeletal muscle diseases), fibrin (visible in tissues with fresh damage, in acute inflammatory reactions), glial fibres (display of gliosis in central nervous system), certain elastic fibers, cartilage and bone matrix. Tungsten from the excessive phosphotungstic acid in the reagent binds all the available hematein and creates blue pigment that selectively stains skeletal striated muscles, fibrin, nuclei and certain other elements. The remainder of the phosphotungstic acid stains red-brown structures such as collagen. Hematoxylin P.T.A. is a component of Hematoxylin P.T.A. kit. Product description HEMATOXYLIN P.T.A. - reagent that contains hematoxylin and phosphotungstic acid for selective staining of tissue structures. Example of use of Hematoxylin P.T.A. as a component of Hematoxylin P.T.A. kit Other sections and reagents that may be used in staining: Fixatives such as BioGnost's neutral buffered formaldehyde solutions: Formaldehyde NB 4%, Formaldehyde NB 10% Dehydrating/rehydrating agent, such as BioGnost's alcohol solutions: Histanol 70, Histanol 80, Histanol 95 and Histanol 100 Clearing agents, such as BioClear xylene or a substitute, such -
Safety Data Sheet According to 1907/2006/EC, Article 31 Date Printed 27.02.2019 Version Number 1 Revision Date 22.06.2015
Page 1/8 Safety data sheet according to 1907/2006/EC, Article 31 Date Printed 27.02.2019 Version number 1 Revision Date 22.06.2015 SECTION 1: Identification of the substance/mixture and of the company/ undertaking · 1.1 Product identifier · Trade name: Phosphotungstic Acid Hydrate · Article number: AGR1213 · CAS Number: 12501-23-4 · 1.2 Relevant identified uses of the substance or mixture and uses advised against Laboratory chemicals, Manufacture of substances · Application of the substance / the preparation: No further relevant information available. · 1.3 Details of the supplier of the safety data sheet · Supplier. Agar Scientific Ltd Parsonage Lane Stansted CM24 8GF United Kingdom [email protected] Tel: +44 (0) 1279 813 519 · Further information obtainable from: Technical Support · 1.4 Emergency telephone number: 24 hours: +44 (0)1856 407333 SECTION 2: Hazards identification · 2.1 Classification of the substance or mixture · Classification according to Regulation (EC) No 1272/2008 GHS05 corrosion Skin Corr. 1B H314 Causes severe skin burns and eye damage. GHS07 Eye Irrit. 2 H319 Causes serious eye irritation. STOT SE 3 H335 May cause respiratory irritation. · 2.2 Label elements · Labelling according to Regulation (EC) No 1272/2008 The substance is classified and labelled according to the CLP regulation. · Hazard pictograms GHS05 GHS07 · Signal word Danger · Hazard statements H314 Causes severe skin burns and eye damage. H335 May cause respiratory irritation. · Precautionary statements P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water [or shower]. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes.