scholarly journals Aesthetic Alteration of Marble Surfaces Caused by Biofilm Formation: Effects of Chemical Cleaning

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 122 ◽  
Author(s):  
Federica Villa ◽  
Davide Gulotta ◽  
Lucia Toniolo ◽  
Luigimaria Borruso ◽  
Cristina Cattò ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Specific Substrate ◽  
Chemical Cleaning ◽  
Aesthetic Results ◽  
Cleaning Procedures ◽  
Functional Profiles ◽  
The Impact ◽  
Cleaning Treatment

Despite the massive presence of biofilms causing aesthetic alteration to the façade of the Monza Cathedral, our team in a previous work proved that the biocolonization was not a primary damaging factor if compared to chemical-physical deterioration due to the impact of air pollution. Nonetheless, the conservators tried to remove the sessile dwelling microorganisms to reduce discolouration. In this research, two nearby sculpted leaves made of Candoglia marble were selected to study the effects of a chemical treatment combining the biocides benzalkonium chloride, hydrogen peroxide and Algophase® and mechanical cleaning procedures. One leaf was cleaned with the biocides and mechanically, and the other was left untreated as control. The impact of the treatment was investigated after 1 month from the cleaning by digital microscopy, environmental scanning electron microscopy, confocal microscopy and molecular methods to determine the composition and the functional profiles of the bacterial communities. Despite the acceptable aesthetic results obtained, the overall cleaning treatment was only partially effective in removing the biofilm from the colonized surfaces and, therefore, not adequately suitable for the specific substrate. Furthermore, the cleaning process selected microorganisms potentially more resistant to biocides so that the efficacy of future re-treatment by antimicrobial agents could be negatively affected.

scholarly journals The Visualization of Biofilms in Chronic Diabetic Foot Wounds Using Routine Diagnostic Microscopy Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Angela Oates ◽  
Frank L. Bowling ◽  
Andrew J. M. Boulton ◽  
Philip G. Bowler ◽  
Daniel G. Metcalf ◽  
...  
Keyword(s):  
Diabetic Foot ◽  
Antimicrobial Agents ◽  
Chronic Wounds ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Diabetic Patients ◽  
Gram Stain ◽  
Bright Field ◽  
Planktonic Bacteria ◽  
Biofilm Matrix

Diabetic foot wounds are commonly colonised by taxonomically diverse microbial communities and may additionally be infected with specific pathogens. Since biofilms are demonstrably less susceptible to antimicrobial agents than are planktonic bacteria, and may be present in chronic wounds, there is increasing interest in their aetiological role. In the current investigation, the presence of structured microbial assemblages in chronic diabetic foot wounds is demonstrated using several visualization methods. Debridement samples, collected from the foot wounds of diabetic patients, were histologically sectioned and examined using bright-field, fluorescence, and environmental scanning electron microscopy and assessed by quantitative differential viable counting. All samples (n= 26) harboured bioburdens in excess of 5 log10CFU/g. Microcolonies were identified in 4/4 samples by all three microscopy methods, although bright-field and fluorescence microscopy were more effective at highlighting putative biofilm morphology than ESEM. Results in this pilot study indicate that bacterial microcolonies and putative biofilm matrix can be visualized in chronic wounds using florescence microscopy and ESEM, but also using the simple Gram stain.

Removal of Aflatoxin B1 and Inhibition of Aspergillus flavus Growth by the Use of Lactobacillus plantarum on Olives

2014 ◽  
Vol 77 (10) ◽  
pp. 1760-1767 ◽  
Author(s):  
FATEN KACHOURI ◽  
HAMIDA KSONTINI ◽  
MOKTAR HAMDI
Keyword(s):  
Lactobacillus Plantarum ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Environmental Scanning Electron Microscopy ◽  
Total Phenolic ◽  
Environmental Scanning ◽  
Fluorescence Detector ◽  
Natural Microflora ◽  
The Impact

Olives can be contaminated with a wide variety of molds (Aspergillus and/or Penicillium) that can be occurring naturally on fresh and processed olives and could support mycotoxin production. The aim of this work was to investigate aflatoxin B1 (AFB1) production by fungi and its bioaccumulation in olives during storage and to study the impact of the application of Lactobacillus plantarum on the inhibition of mold development and production of AFB1. Two different treatments were applied: (i) olives with natural microflora and (ii) olives inoculated with Aspergillus flavus after elimination of natural microflora. AFB1 has been extracted from olives and quantitated by high-performance liquid chromatography using a fluorescence detector. Results showed the absence of this metabolite in the olives for the season 2008 to 2009. In 2009 to 2010, AFB1 was detected at the level of 11 μg/kg. The application of L. plantarum during the storage of olives favors the reduction of the level of AFB1 to 5.9 μg/kg correlated with a decrease in the amount of molds (86.3%). The images obtained by environmental scanning electron microscopy showed that L. plantarum was able to adhere to the olive surface and probably produce a biofilm that inhibits the multiplication of yeast and fungi by oxygen competition. Results showed an increase of antioxidant activity and amount of total phenolic compounds of olives, respectively, by 24 and 8.6%. In many olives contaminated with A. flavus, AFB1 was present at an initial level of 5.15 μg/kg and increased to 6.55 μg/kg after 8 days of storage. The biological detoxification of AFB1 in olives by L. plantarum is confirmed by the reduction of the level of AFB1 to 2.12 μg/kg on day 0 and its absence after 4 days of storage.

scholarly journals Modification of Olive Leaves’ Surface by Ultrasound Cavitation. Correlation with Polyphenol Extraction Enhancement

2020 ◽  
Vol 11 (1) ◽  
pp. 232
Author(s):  
Natacha Rombaut ◽  
Tony Chave ◽  
Sergey I. Nikitenko ◽  
Mohamed El Maâtaoui ◽  
Anne Sylvie Fabiano-Tixier ◽  
...  
Keyword(s):  
Cross Sections ◽  
Leaf Surface ◽  
Environmental Scanning Electron Microscopy ◽  
Acoustic Cavitation ◽  
Environmental Scanning ◽  
Plant Structure ◽  
Olive Leaves ◽  
Treated Leaf ◽  
Polyphenol Extraction ◽  
The Impact

We investigated the impact of ultrasound at 20 kHz on olive leaves to understand how acoustic cavitation could increase polyphenol extraction. Application of ultrasound to whole leaf from 5 to 60 min enabled us to increase extraction from 6.96 to 48.75 µg eq. oleuropein/mL of extract. These results were correlated with Environmental Scanning Electron Microscopy, allowing for leaf surface observation and optical microscopy of treated leaf cross sections to understand histochemical modifications. Our observations suggest that the effectiveness of ultrasound applied to extraction is highly dependent on plant structure and on how this material will react when subjected to acoustic cavitation. Ultrasound seems to impact the leaves by two mechanisms: cuticle erosion, and fragmentation of olive leaf surface protrusions (hairs), which are both polyphenol-rich structures.

scholarly journals Influence of Low-Pressure Treatment on the Morphological and Compositional Stability of Microscopic Ettringite

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2720
Author(s):  
Patrick A. Kißling ◽  
Franziska Lübkemann ◽  
Tabea von Bronk ◽  
Dario Cotardo ◽  
Lei Lei ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Environmental Scanning Electron Microscopy ◽  
Bound Water ◽  
Low Pressure ◽  
Environmental Scanning ◽  
Pressure Treatment ◽  
X Ray Diffraction ◽  
Compositional Stability ◽  
Drying Conditions ◽  
The Impact

The impact of low-pressure treatment on the crystal structure, morphology, and chemical composition of ettringite, due to their major importance with respect to processability (i.a., drying conditions) and to the analysis of ettringite-containing samples, is examined utilizing X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, and environmental scanning electron microscopy. Synthetic ettringite was treated for various durations (5 min up to 72 h) and at two different levels of low-pressure (4.0 mbar and 60 µbar). Evaluation showed a correlation between the procedural parameters (time and pressure), the chemical composition, and the morphology of ettringite. The experiments reveal that, when exposed to 4 mbar pressure, nearly no changes occur in the ettringite’s morphology, whereas the crystals undergo swelling and slight deformations at very low pressures (60 µbar and 35.3 nbar), which is attributed to the loss of bound water and the partial transformation from ettringite to quicklime, anhydrite, and calcium aluminate. Furthermore, the strongly dehydrated ettringite shows the same morphology.

Structural changes in spruce wood during different steps of steam explosion pretreatment

Holzforschung ◽  
2015 ◽  
Vol 69 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Muhammad Muzamal ◽  
Kerstin Jedvert ◽  
Hans Theliander ◽  
Anders Rasmuson
Keyword(s):  
Steam Explosion ◽  
Structural Changes ◽  
Mercury Porosimetry ◽  
Environmental Scanning Electron Microscopy ◽  
Steam Treatment ◽  
Environmental Scanning ◽  
Wood Material ◽  
Spruce Wood ◽  
Pretreatment Technology ◽  
The Impact

Abstract Steam explosion (SE) is a promising hydrothermal pretreatment technology for future biorefineries. In this study, the three steps of the steam explosion process, (1) the steam treatment (2) the explosion, and (3) the impact step were separately considered and their effects on structural changes of wood were studied. The SE experiments were performed on single wood pieces in different experimental set-ups at 7 and 14 bar pressure with 5 and 10 min treatment times. Mercury porosimetry and environmental scanning electron microscopy analyses were conducted to characterise both internal and external changes in the wood. It was found that the explosion step is not responsible for the disintegration of the wood material into small pieces; instead, the disintegration occurs due to impact of softened wood chips. However, the porosity profiles of the tracheids change during the explosion step. Altogether, all three steps of the SE process contribute in a synergistic way to an increase in pore size and total intrusion volume.

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.

Environmental Scanning for Organisational Effectiveness: A Study of Select MSMEs of Jammu and Kashmir, India

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Vinay Chauhan ◽  
Sushma Kaushal
Keyword(s):  
Organizational Effectiveness ◽  
Business Environment ◽  
Two Dimensions ◽  
The State ◽  
The Other ◽  
Political Environment ◽  
Environmental Scanning ◽  
Jammu And Kashmir ◽  
Economic Dimension ◽  
The Impact

Environmental scanning yields greater anticipatory management that provides important inputs for aquitision and use of information for planning and designing organization strategies. Apart from this, effective environmental scanning activities are likely to deal with threats and grasp the opportunities to finally link with enhancing organizational effectiveness. In fact this relationship matrix has led the researchers to conduct an environmental scanning through an examination of the existing status the components of the macro-environment vis-a-vis their relationship with the organizational effectiveness. There are a number of approaches, which describe the macro-environment, of which PEST analysis is regarded as the most common approach for considering the external business environment. Thus, the present study applies PEST analysis to scan the existing business environment. Jammu and Kashmir due to its peculiar political, geographical, economic, and socio-cultural features, had led its cost mountain economy become a distinctive identity. Despite the fact that the state has rich endowments, international relations with its neighbours vis-a-vis its impact on political environment also pose developmental challenges for the business units operating in the state. This has provided valid rationale for conducting the present. The environmental scanning is done through the perception of the select entrepreneurs operating MSMEs in the state of J & K. An impact analysis of environmental factors (PEST) on the organizational effectiveness is also done in the study. The findings of the study show that the political environment of the state that is not favourable for entrepreneural development whereas the rest of the other drivers of PEST i.e. economic environment, socio-cultural environment, and technological environment show a favourable response of the entrepreneurs. In terms of cause and effect relationship, it is found that the first two drivers of the PEST i.e. political and economic dimension impacts OE positively whereas the other two dimensions namely socio-cultural and technological impacts OE negatively but it is pertinent to mention that the impact is very less and is insigninificant. The study also suggests some of strategic options for developing and creating an enabling environment for successful entrepreneurial development to achieve integrated development of the state.

scholarly journals Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Fatma Y. Ahmed ◽  
Usama Farghaly Aly ◽  
Rehab Mahmoud Abd El-Baky ◽  
Nancy G. F. M. Waly
Keyword(s):  
Titanium Dioxide ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Efflux Pumps ◽  
Antibiofilm Activity ◽  
The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

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