scholarly journals Influence of Method on the Apparent Size Distribution of Bacterioplankton Cells: Epifluorescence Microscopy Compared to Scanning Electron Microscopy

1981 ◽  
Vol 5 ◽  
pp. 103-106 ◽  
Author(s):  
JA Fuhrman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Size Distribution ◽  
Apparent Size ◽  
Epifluorescence Microscopy ◽  
Scanning Electron

scholarly journals Phase-separated polymer blends: Complementary studies between scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy

2001 ◽  
Vol 80 (7) ◽  
pp. 949-955 ◽  
Author(s):  
E. G. Granados ◽  
J. González-Benito ◽  
J. Baselga ◽  
D. Dibbern-Brunelli ◽  
T. D. Z. Atvars ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polymer Blends ◽  
Epifluorescence Microscopy ◽  
Scanning Electron

scholarly journals Síntesis y caracterización de xerogeles de sílice obtenidos por la ruta de los atranos

2020 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Lenin Jose Huerta ◽  
Rebeca Torres Fajardo ◽  
Juan Primera Ferrer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Evaporation ◽  
Scanning Calorimetry ◽  
Xerogel Sample ◽  
Scanning Electron

  En este trabajo se investigó la síntesis de xerogeles de sílice por la vía de los atranos, y se evaluó la influencia de la concentración del agente iniciador (HCl) y la presencia o no del surfactante (CTAB), sobre el tiempo de gelificación y las propiedades texturales de los materiales obtenidos. Las caracterizaciones se realizaron mediante: isotermas de adsorción-desorción de nitrógeno, microscopía electrónica de barrido y calorimetría diferencial de barrido. Los tiempos de gelificación aumentaron en la medida que se disminuyó la concentración del HCl y, en general, los xerogeles preparados presentaron una buena rigidez cuando estos se dejaron a tiempos mayores de 20 horas. La distribución de tamaño de poro (determinada mediante la técnica BJH) para los xerogeles calcinados preparados sin surfactante presentaron un sistema de poro bien definido de 16,4 nm en promedio, mientras los xerogeles calcinados preparados con surfactante no presentaron una distribución de tamaño de poro bien definida, ambos casos mostraron áreas superficiales de alrededor de 580 m2/g. Por calorimetría diferencial de barrido se observaron dos picos para la muestra de xerogel sin surfactante, uno alrededor de 80 °C debido a la evaporación del agua y el otro a 265 °C atribuido a la descomposición de la materia orgánica presente en el gel; para la muestra de xerogel con surfactante se observó un pico bien definido a 130 °C, atribuido a la pérdida del agua. Por microscopía electrónica de barrido, en los xerogeles calcinados se observaron poros con tamaños alrededor de los 15 nm.   Palabra clave: Xerogel, atrano, surfactante, sílice, gelificación.   Abstract In this work, the synthesis of silica xerogels by the atrane way was investigated, evaluating: concentration influence of the initiating agent (HCl) and the presence or not of the surfactant (CTAB), over gelation time, and the textural properties of the obtained materials. Characterizations were carried out by nitrogen adsorption-desorption isotherms, scanning electron microscopy, and differential scanning calorimetry. Gelation times increased as the HCl concentration decreased, and, in general, xerogels prepared presented good rigidity when they were aging for times greater than 20 hours. Pore size distribution (determined by the BJH technique) for the calcined xerogels prepared without surfactant presented a well-defined pore system of 16.4 nm on average, while the calcined xerogels prepared with surfactant did not present a well-defined pore size distribution, both cases showed surface areas of around 580 m2/g. In differential scanning calorimetry, two peaks were observed for the xerogel sample without surfactant, one around 80 °C due to water evaporation, and the other one at 265 °C attributed to the decomposition of organic matter present in the gel; for the surfactant xerogel sample, a well-defined peak was observed at 130 °C, attributed to the loss of water. By scanning electron microscopy, pores with sizes around 15 nm in calcined xerogels were observed.   Keywords: Xerogel, atrane, surfactant, silica, gelation.  

scholarly journals Comparison of techniques for counting prokaryotes in marine planktonic and biofilm samples

2021 ◽  
Vol 85 (3) ◽  
pp. 211-220
Author(s):  
Vanessa Ochi Agostini ◽  
Letícia Terres Rodrigues ◽  
Alexandre José Macedo ◽  
Erik Muxagata
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Damage ◽  
High Variability ◽  
Epifluorescence Microscopy ◽  
Free Living ◽  
Marine Biofilm ◽  
Comparison Of Techniques ◽  
Green Fluorescent ◽  
Scanning Electron

Though a large number of techniques are available for the study of aquatic bacteria, the aim of this study was to establish a technique for analysing free-living and biofilm prokaryotic cells through laboratory assays. In particular, we wished to analyse the efficiency of ultrasound to detach and disrupt biofilm, to obtain an efficient stain treatment for quantifying free-living and biofilm prokaryotes in flow cytometry (FC), and to compare epifluorescence microscopy (EFM), scanning electron microscopy (SEM) and FC for quantifying free-living and biofilm prokaryotes#. Marine-grade plywood substrates were immersed in natural marine water that was conditioned for 12 days. At 6 and 12 days, water aliquots and substrates were removed to estimate free-living and biofilm prokaryote density. Ultrasound efficiently removed marine biofilm from substrates (up to 94%) without cell damage. FC analysis (unstained) reliably quantified marine plankton and young or mature biofilm prokaryotes compared with other staining (acridine orange, 4′,6-diamidino-2-phenylindole, propidium iodide and green fluorescent nucleic acid), EFM or SEM techniques. FC and SEM achieved similar results, while a high variability was observed in the EFM technique. FC was faster and more precise than SEM because the count is not dependent on the observer.

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