Microbial Aspects in Corrosion Studies of Stainless Steels

2011 ◽  
Vol 183 ◽  
pp. 117-124
Author(s):  
Joanna Michalska
Keyword(s):  
Bacterial Cells ◽  
Hydrogen Damage ◽  
Materials Engineering ◽  
Research Areas ◽  
Microbially Influenced Corrosion ◽  
Corrosion Studies ◽  
Adequate Understanding ◽  
Key Factor ◽  
Complex Boundary ◽  
Microbial Risks

Microbially influenced corrosion (MIC) has been focusing increasing attention from different research areas in the last years, as an answer to the demand of wide variety of industries and degradation cases. The difficulty in reaching an adequate understanding of corrosion processes induced by microorganisms has result in cross-fertilization of ideas between researchers from different disciplines like microbiology, electrochemistry, metallurgy and materials engineering. Different MIC mechanisms can be simultaneously or alternately occuring on various materials, where a complex boundary layer of corrosion products, bacterial cells and other environmental factors are present on the surface. The paper discusses new aspects of MIC mechanisms induced by sulphate reducing bacteria species, taking into consideration modern techniques and new approaches in the study. Practical cases concerning microbial risks, failures illustrate the complexity of this phenomena: from local corrosion problems through stress corrosion cracking and hydrogen damage. The role of microstructure and chemical composition of materials is also highlited as a key factor in microbial damaging. In addition to this, the principal morphologies of attack and cracking are described.

Attachment of oral bacteria to titanium surfaces: An SEM study

1994 ◽  
Vol 52 ◽  
pp. 468-469
Author(s):  
J. E. Laffoon ◽  
R. L. Anderson ◽  
J. C. Keller ◽  
C. D. Wu-Yuan
Keyword(s):  
Technical Problem ◽  
Titanium Implant ◽  
Oral Bacteria ◽  
Bacterial Cells ◽  
Thin Sections ◽  
Surface Ultrastructure ◽  
Sem Study ◽  
Key Factor ◽  
Titanium Surfaces

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).

scholarly journals Recent Development of Rapid Antimicrobial Susceptibility Testing Methods through Metabolic Profiling of Bacteria

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 311
Author(s):  
Chen Chen ◽  
Weili Hong
Keyword(s):  
Antimicrobial Susceptibility ◽  
Metabolic Profiling ◽  
Bacterial Infections ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Bacterial Metabolism ◽  
Resistant Bacteria ◽  
Bacterial Cells ◽  
Inappropriate Use ◽  
Key Factor

Due to the inappropriate use and overuse of antibiotics, the emergence and spread of antibiotic-resistant bacteria are increasing and have become a major threat to human health. A key factor in the treatment of bacterial infections and slowing down the emergence of antibiotic resistance is to perform antimicrobial susceptibility testing (AST) of infecting bacteria rapidly to prescribe appropriate drugs and reduce the use of broad-spectrum antibiotics. Current phenotypic AST methods based on the detection of bacterial growth are generally reliable but are too slow. There is an urgent need for new methods that can perform AST rapidly. Bacterial metabolism is a fast process, as bacterial cells double about every 20 to 30 min for fast-growing species. Moreover, bacterial metabolism has shown to be related to drug resistance, so a comparison of differences in microbial metabolic processes in the presence or absence of antimicrobials provides an alternative approach to traditional culture for faster AST. In this review, we summarize recent developments in rapid AST methods through metabolic profiling of bacteria under antibiotic treatment.

Terra rossa as the substrate for biological phosphate removal from wastewater

Clay Minerals ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 725-738 ◽  
Author(s):  
G. Durn ◽  
J. Hrenovic ◽  
L. Sekovanic
Keyword(s):  
Phosphate Removal ◽  
Bacterial Cells ◽  
Total Iron Content ◽  
Terra Rossa ◽  
Acinetobacter Junii ◽  
Immobilized Bacteria ◽  
Support Materials ◽  
Three Samples ◽  
Key Factor ◽  
Extractable Iron

AbstractThree samples of terra rossa were shown to be efficient adsorbents of phosphate [P(V)] from wastewater and removed 29.9–32.6% of P(V). The total iron content in terra rossa was the key factor which determined the P(V) removal from wastewater. The original samples of terra rossa were effective support materials for the immobilization of metabolically active P(V)-accumulating bacteriaAcinetobacter junii(0.56–2.47×1010CFU g–1). The removal of oxalate-extractable iron from original sample of terra rossa increased the number of immobilized bacteria to 1.34×10–11CFU g–1, which is the largest number of immobilized bacteria reported in the literature so far. In reactors containing theA. juniiand terra rossa P(V) was removed from wastewater by simultaneous adsorption onto terra rossa and accumulation inside bacterial cells, resulting in 40.5–62.5% of P(V) removal. Terra rossa is a promising substrate for biological P(V) removal from wastewater, acting both as adsorbent of P(V) and carrier of P(V)-accumulating bacteria.

scholarly journals Entropy-Based Algorithms for Signal Processing

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 621
Author(s):  
Gwanggil Jeon ◽  
Abdellah Chehri
Keyword(s):  
Information Theory ◽  
Signal Processing ◽  
Computer Science ◽  
Important Research ◽  
Research Areas ◽  
Key Factor

Entropy, the key factor of information theory, is one of the most important research areas in computer science [...]

scholarly journals Integrating User eXperience practices into software development processes: implications of the UX characteristics

2017 ◽  
Vol 3 ◽  
pp. e130 ◽  
Author(s):  
Pariya Kashfi ◽  
Agneta Nilsson ◽  
Robert Feldt
Keyword(s):  
Software Development ◽  
User Experience ◽  
Software Quality ◽  
Quality Characteristics ◽  
Mitigation Strategies ◽  
Software Systems ◽  
Software Companies ◽  
Research Areas ◽  
Key Factor ◽  
Past Experiences

User eXperience (UX) is a key factor in the success of software systems. Many software companies face challenges in their work with UX. Existing research does not analyze UX practices and challenges in relation to other software quality characteristics or, in particular, in relation to usability. A better understanding of these challenges can help researchers and practitioners better address them in the future. In this empirical study, we have interviewed 17 practitioners with different backgrounds and occupations from eight software development companies. Their responses are coded, and analyzed with thematic analysis. We report eight themes of challenges that practitioners face in their work with UX. While some of these challenges partly overlap with those reported in existing literature about usability or other software quality characteristics, the participants of our study either view many of the challenges as unique to UX, or more severe in the case of UX. Although at a superficial level challenges of UX and other quality characteristics overlap, we differentiate these challenges at a deeper level through the five main characteristics of UX:subjective,holistic,dynamic,context-dependentandworthwhile. In particular, we identified that these characteristics have at least 20 implications (i.e. additional difficulties) for day-to-day work of practitioners. We found that 11 of these implications have been previously reported in literature. However, to the best of our knowledge, the remaining nine implications are unique to our study. These implications can explain why practitioners perceive the challenges to be more severe than for other quality characteristics. Most importantly, they can explain the industry’s lopsided focus on the pragmatic aspect of UX. Our findings can be useful for researchers in identifying new and industry-relevant research areas and for practitioners to learn from empirically investigated challenges in UX work, and base their improvement efforts on such knowledge. Identifying and investigating the overlaps underlines the importance of these challenges, and can also help finding research areas not only for enhancing UX work but also software quality in general. It also makes it easier for practitioners to spot, better understand as well as find mitigation strategies for UX, through learning from past experiences and developments in the area of software quality.

scholarly journals Tryptophan-like and humic-like fluorophores are extracellular in groundwater: implications as real-time faecal indicators

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
James P. R. Sorensen ◽  
Andrew F. Carr ◽  
Jacintha Nayebare ◽  
Djim M. L. Diongue ◽  
Abdoulaye Pouye ◽  
...  
Keyword(s):  
Natural Organic Matter ◽  
Urban Population ◽  
Indicator Bacteria ◽  
Bacterial Cells ◽  
Extracellular Material ◽  
Faecal Indicator Bacteria ◽  
Controlling Variables ◽  
Microbial Risks ◽  
Entire Dataset ◽  
Faecal Indicators

Abstract Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus considered extracellular (median 96.9%). ΔTLF was only significant in more urbanised study areas where TLF was greatest. Beneath Dakar, Senegal, ΔTLF was significantly correlated to total bacterial cells (ρs 0.51). No significant change in HLF following filtration across all data indicates these fluorophores are extracellular. Our results suggest that TLF and HLF are more mobile than faecal indicator bacteria and larger pathogens in groundwater, as the predominantly extracellular fluorophores are less prone to straining. Consequently, TLF/HLF are more precautionary indicators of microbial risks than faecal indicator bacteria in groundwater-derived drinking water.

scholarly journals New Twists and Turns in Bacterial Locomotion and Signal Transduction

2019 ◽  
Vol 201 (20) ◽  
Author(s):  
Kylie J. Watts ◽  
Ady Vaknin ◽  
Clay Fuqua ◽  
Barbara I. Kazmierczak
Keyword(s):  
Signal Transduction ◽  
De Novo ◽  
Electron Tomography ◽  
Bacterial Cells ◽  
Research Areas ◽  
Flagellar Motors ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT Prokaryotic organisms occupy the most diverse set of environments and conditions on our planet. Their ability to sense and respond to a broad range of external cues remain key research areas in modern microbiology, central to behaviors that underlie beneficial and pathogenic interactions of bacteria with multicellular organisms and within complex ecosystems. Advances in our understanding of the one- and two-component signal transduction systems that underlie these sensing pathways have been driven by advances in imaging the behavior of many individual bacterial cells, as well as visualizing individual proteins and protein arrays within living cells. Cryo-electron tomography continues to provide new insights into the structure and function of chemosensory receptors and flagellar motors, while advances in protein labeling and tracking are applied to understand information flow between receptor and motor. Sophisticated microfluidics allow simultaneous analysis of the behavior of thousands of individual cells, increasing our understanding of how variance between individuals is generated, regulated, and employed to maximize fitness of a population. In vitro experiments have been complemented by the study of signal transduction and motility in complex in vivo models, allowing investigators to directly address the contribution of motility, chemotaxis, and aggregation/adhesion on virulence during infection. Finally, systems biology approaches have demonstrated previously uncharted areas of protein space in which novel two-component signal transduction pathways can be designed and constructed de novo. These exciting experimental advances were just some of the many novel findings presented at the 15th Bacterial Locomotion and Signal Transduction conference (BLAST XV) in January 2019.

Analysis of radicals and radical reaction products in cell signalling and biomolecular damage: the long hard road to gold-standard measures

2011 ◽  
Vol 39 (5) ◽  
pp. 1217-1220 ◽  
Author(s):  
Paul G. Winyard ◽  
Corinne M. Spickett ◽  
Helen R. Griffiths
Keyword(s):  
Free Radical ◽  
Cell Signalling ◽  
Radical Reaction ◽  
Research Area ◽  
Oxygen Species ◽  
Reaction Products ◽  
Research Areas ◽  
Key Factor ◽  
Topical Interest

The field of free radical biology and medicine continues to move at a tremendous pace, with a constant flow of ground-breaking discoveries. The following collection of papers in this issue of Biochemical Society Transactions highlights several key areas of topical interest, including the crucial role of validated measurements of radicals and reactive oxygen species in underpinning nearly all research in the field, the important advances being made as a result of the overlap of free radical research with the reinvigorated field of lipidomics (driven in part by innovations in MS-based analysis), the acceleration of new insights into the role of oxidative protein modifications (particularly to cysteine residues) in modulating cell signalling, and the effects of free radicals on the functions of mitochondria, extracellular matrix and the immune system. In the present article, we provide a brief overview of these research areas, but, throughout this discussion, it must be remembered that it is the availability of reliable analytical methodologies that will be a key factor in facilitating continuing developments in this exciting research area.

scholarly journals Uptake of Ozenoxacin and Other Quinolones in Gram-Positive Bacteria

2021 ◽  
Vol 22 (24) ◽  
pp. 13363
Author(s):  
Yuly López ◽  
Laura Muñoz ◽  
Domingo Gargallo-Viola ◽  
Rafael Cantón ◽  
Jordi Vila ◽  
...  
Keyword(s):  
Bacterial Cell ◽  
Dry Weight ◽  
Bacterial Cells ◽  
Topoisomerase Iv ◽  
Gram Positive Bacteria ◽  
Agar Disc ◽  
Key Factor ◽  
Ic50 Values ◽  
Important Challenge

The big problem of antimicrobial resistance is that it requires great efforts in the design of improved drugs which can quickly reach their target of action. Studies of antibiotic uptake and interaction with their target it is a key factor in this important challenge. We investigated the accumulation of ozenoxacin (OZN), moxifloxacin (MOX), levofloxacin (LVX), and ciprofloxacin (CIP) into the bacterial cells of 5 species, including Staphylococcus aureus (SA4-149), Staphylococcus epidermidis (SEP7602), Streptococcus pyogenes (SPY165), Streptococcus agalactiae (SAG146), and Enterococcus faecium (EF897) previously characterized.The concentration of quinolone uptake was estimated by agar disc-diffusion bioassay. Furthermore, we determined the inhibitory concentrations 50 (IC50) of OZN, MOX, LVX, and CIP against type II topoisomerases from S. aureus.The accumulation of OZN inside the bacterial cell was superior in comparison to MOX, LVX, and CIP in all tested species. The accumulation of OZN inside the bacterial cell was superior in comparison to MOX, LVX, and CIP in all tested species. The rapid penetration of OZN into the cell was reflected during the first minute of exposure with antibiotic values between 190 and 447 ng/mg (dry weight) of bacteria in all strains. Moreover, OZN showed the greatest inhibitory activity among the quinolones tested for both DNA gyrase and topoisomerase IV isolated from S. aureus with IC50 values of 10 and 0.5 mg/L, respectively. OZN intracellular concentration was significantly higher than that of MOX, LVX and CIP. All of these features may explain the higher in vitro activity of OZN compared to the other tested quinolones.

scholarly journals One and a half million medical papers reveal a link between author gender and attention to gender and sex analysis

2018 ◽  
Author(s):  
Mathias W. Nielsen ◽  
Jens Peter Andersen ◽  
Londa Schiebinger ◽  
Jesper W. Schneider
Keyword(s):  
Medical Research ◽  
Medical Science ◽  
Women Authors ◽  
Research Papers ◽  
Related Factors ◽  
Research Areas ◽  
Women's Participation ◽  
Participation Of Women ◽  
Key Factor ◽  
Potential Link

Gender and sex analysis is increasingly recognized as a key factor in creating better medical research and healthcare. Using a sample of more than 1.5 million medical research papers, our study examined the potential link between women’s participation in medical science and attention to gender- and sex-related factors in disease-specific research. Adjusting for variations across countries, disease topics and medical research areas, we compared the participation of women authors in studies that do and do not involve gender and sex analysis. Overall, our results show a robust positive correlation between women’s authorship and a study’s likelihood of engaging gender and sex analysis. These findings corroborate discussions of how women’s participation in medical science links to research outcomes, and illustrate the mutual benefits of promoting both women’s scientific advancement and the integration of gender and sex analysis into medical research.

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