scholarly journals Diagnosis of the Diatom Community upon Biofilm Development on Stainless Steels in Natural Freshwater

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Caroline Richard ◽  
Smita Mitbavkar ◽  
Jessem Landoulsi
Keyword(s):  
Stainless Steels ◽  
Environmental Scanning Electron Microscopy ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Environmental Scanning ◽  
Freshwater Ecosystem ◽  
Centric Diatom ◽  
Diatom Community ◽  
Biofilm Development ◽  
Pennate Diatoms

This paper reports the development of biofilms on stainless steels (SS) upon exposure in a natural freshwater ecosystem for about six months and focuses on the composition of diatom populations. By using environmental scanning electron microscopy (ESEM) technique, we provide a detailed description regarding diatom identification at species level as well as their main characteristics, including type, morphology, ability to form colony, and motility. Results reveal the presence of both prostrate (initial colonizers) and stalked (late colonizers) forms. Pennate diatoms,Cocconeis placentulaandAmphora coffeaeformis,and a centric diatom,Melosira varians, are shown to be the abundant forms regardless of the SS type. Pennate diatoms dominate the community and are directly attached to the substratum, whereas the centric form is entangled in the biofilm matrix in a significant number. The dominance of adnate forms suggests that these cells are sturdy and successfully maintaining their population. In situ monitoring of the electrochemical response of immersed materials showed ennoblement of the open circuit potential, which seems to be due to the biogenic production of H2O2, detected in a significant amount within the biofilms. The substantial enrichment of biofilms with diatoms potentially suggests the implication of these microorganisms in the process of ennoblement. A mechanism is proposed in this paper describing the possible interactions of diatom community with SS in the studied ecosystem.

scholarly journals 616 Preventing Biofilms on BACTIGON® Coated Camstent Urinary Catheters in Patients Undergoing Elective Colorectal Surgery: A Single Centre Pilot Study

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
C Lewis-Lloyd ◽  
J Dubern ◽  
K Kalenderski ◽  
N Halliday ◽  
M Alexander ◽  
...  
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Bacterial Cells ◽  
Urinary Catheters ◽  
Elective Colorectal Surgery ◽  
Mineral Compositions ◽  
Microscopy Data ◽  
Tract Infections ◽  
Biofilm Development ◽  
Hospital Acquired

Abstract Introduction Catheter associated urinary tract infections account for 40% of hospital acquired infections. They are associated with biofilms consisting of bacterial cells enmeshed in a self-generated extracellular matrix adhering to catheter surfaces. We have developed a novel polymer family that, coated onto urinary catheters, creates a “non-stick” surface preventing biofilm development. Method Prospective cohort of elective colorectal patients recruited pre-operatively, received a standard silicone (SS) or Camstent (BACTIGON®) coated urinary catheter. After removal, catheters were cut longitudinally into 3 segments. Biomass and biomineralisation were analysed using confocal fluorescence microscopy. Data were normalised by square rooting the catheter indwelling duration. Environmental scanning electron microscopy and energy dispersive x-ray spectroscopy was performed. Results Of 40 patients, 20 each received a SS or coated catheter. Between SS and coated catheters, average indwelling duration was similar and biofilm biomass was 32.068µg/cm2 (95%CI ±21.950) vs. 1.948µg/cm2 (95%CI ±2.595) (P = 0.0111). Confocal microscopy suggested a 93.93% reduction in biofilm biomass on coated catheters. Mineral compositions were different with biofilm and struvite/apatite on SS and calcium oxalate, endogenously derived, on coated catheters. Conclusions Inert BACTIGON® coated catheters appear superior at preventing biofilm formation than SS catheters. Clinical trials are needed to determine the clinical and health economic benefit of this intervention.

Technical Note: Suppression of Anodic Kinetics of Stainless Steels During Biofilm Development in Natural Seawater

CORROSION ◽  
10.5006/3327 ◽  
2019 ◽  
Vol 75 (11) ◽  
pp. 1300-1306
Author(s):  
M. Eashwar ◽  
A. Lakshman Kumar ◽  
G. Sreedhar ◽  
S. Vengatesan ◽  
R. Ananth ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Open Circuit ◽  
Technical Note ◽  
Practical Significance ◽  
Natural Seawater ◽  
Passive Region ◽  
Current Time ◽  
Current Densities ◽  
Biofilm Development ◽  
Kinetics Of

The anodic kinetics of three stainless steels, viz. UNS S31600, S44660, and N08367, in gently flowing natural seawater was investigated. Potentiodynamic anodic polarization showed two distinct passive regimes emerging with biofilm development. A dramatic decrease of anodic current densities (p < 10−4) was recorded in the lower passive region near the ennobled open-circuit potential, accompanied by an increase of the breakdown potential by over 0.2 V for Alloy S31600. However, significant broadening of the transpassive region was observed on all the three alloys tested. Further, for Alloys S44660 and N08367, the second passive region was altered during biofilm growth, which resulted in enhanced peak current densities. These seemingly undesired effects, nonetheless, were detected far beyond the domain of practical significance. Potentiostatic current-time curves for Alloy N08367 further confirmed the suppression of anodic kinetics in the lower passive region. Evans diagrams constructed from actual polarization curves provided fundamentally important insights that passivity promotion can be independent of microbially enhanced cathodic kinetics.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Detector strategies for environmental scanning electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1296-1297
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Vacuum ◽  
Environmental Scanning Electron Microscopy ◽  
Charge Carriers ◽  
Environmental Scanning ◽  
Surface Information ◽  
X Ray ◽  
Detector Electrode ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

Characterization of Thin Polymer Blend Films using ESEM – No Charging, No Staining.

2001 ◽  
Vol 707 ◽  
Author(s):  
Ian C. Bache ◽  
Catherine M. Ramsdale ◽  
D. Steve Thomas ◽  
Ana-Claudia Arias ◽  
J. Devin MacKenzie ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Cross Sectional ◽  
Blend Films ◽  
Thin Polymer ◽  
Device Applications ◽  
Scanning Electron

ABSTRACTCharacterising the morphology of thin films for use in device applications requires the ability to study both the structure within the plane of the film, and also through its thickness. Environmental scanning electron microscopy has proved to be a fruitful technique for the study of such films both because contrast can be seen within the film without the need for staining (as is conventionally done for electron microscopy), and because cross-sectional images can be obtained without charging artefacts. The application of ESEM to a particular blend of relevance to photovoltaics is described.

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