Invariants of the time reversal operator and characterization of solid media: An overview

2013 ◽  
Vol 134 (5) ◽  
pp. 4033-4033
Author(s):  
Claire Prada
Keyword(s):  
Time Reversal ◽  
Solid Media

scholarly journals Fully Automated Microsystem for Unmediated Electrochemical Characterization, Visualization and Monitoring of Bacteria on Solid Media; E. coli K-12: A Case Study

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 131 ◽  
Author(s):  
Cesar A. Hernandez ◽  
Valerio Beni ◽  
Johann F. Osma
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Tests ◽  
E Coli ◽  
Solid Media ◽  
Automated Platform ◽  
The Moment ◽  
K 12 ◽  
Electrochemical Monitoring

In this paper, we present a non-fluidic microsystem for the simultaneous visualization and electrochemical evaluation of confined, growing bacteria on solid media. Using a completely automated platform, real-time monitoring of bacterial and image-based computer characterization of growth were performed. Electrochemical tests, using Escherichia coli K-12 as the model microorganism, revealed the development of a faradaic process at the bacteria–microelectrode interface inside the microsystem, as implied by cyclic voltammetry and electrochemical impedance spectrometry measurements. The electrochemical information was used to determine the moment in which bacteria colonized the electrode-enabled area of the microsystem. This microsystem shows potential advantages for long-term electrochemical monitoring of the extracellular environment of cell culture and has been designed using readily available technologies that can be easily integrated in routine protocols. Complementarily, these methods can help elucidate fundamental questions of the electron transfer of bacterial cultures and are potentially feasible to be integrated into current characterization techniques.

3D GPR characterization of buried metallic and plastic tanks using time-reversal processing technique

2020 ◽  
Author(s):  
Túlio Cordeiro Bicudo ◽  
Vinícius Rafael Neris dos Santos ◽  
Jorge Luís Porsani ◽  
Fernando Lisboa Teixeira
Keyword(s):  
Time Reversal ◽  
Processing Technique ◽  
3D Gpr

scholarly journals Spectroscopic Characterization of Natural Melanin from a Streptomyces cyaneofuscatus Strain and Comparison with Melanin Enzymatically Synthesized by Tyrosinase and Laccase

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1916 ◽  
Author(s):  
Maher Al Khatib ◽  
Mohamed Harir ◽  
Jessica Costa ◽  
Maria Baratto ◽  
Irene Schiavo ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Water Soluble ◽  
Stable Free Radical ◽  
Paramagnetic Resonance ◽  
Solid Media ◽  
Algerian Sahara ◽  
X Band ◽  
Ft Ir ◽  
Synthetic Pigments

An actinobacteria strain was isolated from Algerian Sahara soil and assigned to Streptomyces cyaneofuscatus Pridham et al. 1958 species. This strain was selected for its ability to produce melanin exopigments in liquid and solid media. Melanin synthesis was associated with tyrosinase activity and the enzyme from this strain was isolated and biochemically characterized. Synthetic melanin was then enzymatically produced using the S. cyaneofuscatus Pridham et al. 1958 tyrosinase. As this enzyme showed a higher diphenolase activity, a synthetic melanin from the enzymic oxidation of 3,4-dihydroxyphenylalanine (dopa) was obtained by the use of a Trametes versicolor (L.) Lloyd laccase for comparison. The natural and synthetic pigments were physico-chemically characterized by the use of ultraviolet (UV)-Visible, and Fourier transform infrared (FT-IR) and multifrequency electron paramagnetic resonance (EPR) spectroscopies. All the melanin samples displayed a stable free radical when analyzed by X-band EPR spectroscopy. Once the samples were recorded at Q-band EPR, a copolymer derived from a mixture of different constituents was evident in the natural melanin. All radical species were analyzed and discussed. The use of water-soluble melanin naturally produced by S. cyaneofuscatus Pridham et al. 1958 represents a new biotechnological alternative to commercial insoluble pigments.

The detection and characterization of buried resonant targets by iterative, single‐channel time reversal

2008 ◽  
Vol 123 (5) ◽  
pp. 3185-3185
Author(s):  
Ronald A. Roy ◽  
Zachary J. Waters ◽  
Benjamin R. Dzikowicz ◽  
R. Glynn Holt
Keyword(s):  
Time Reversal ◽  
Single Channel

Real‐time characterization of unstationary flows using a time‐reversal mirror

1998 ◽  
Vol 103 (5) ◽  
pp. 2910-2910
Author(s):  
Agnes Maurel ◽  
Julien De Rosny ◽  
Sebastien Manneville ◽  
Philippe Roux ◽  
Mathias Fink
Keyword(s):  
Real Time ◽  
Time Reversal ◽  
Time Reversal Mirror

Biofilms in Sewer Systems – Characterization of the Bacterial Biocenosis and Its Metabolic Activity

1994 ◽  
Vol 29 (7) ◽  
pp. 385-388 ◽  
Author(s):  
D. Roth ◽  
H. Lemmer
Keyword(s):  
Metabolic Activity ◽  
Heterotrophic Bacteria ◽  
Anaerobic Bacteria ◽  
Population Densities ◽  
Sewer Systems ◽  
Solid Media ◽  
Alanine Aminopeptidase ◽  
High Concentrations ◽  
Metabolic Activities

Biofilms sampled from sewers discharging domestic and trade wastewater, respectively, were characterized by determining the population densities of different groups of heterotrophic bacteria as well as by measuring their metabolic activities. Population densities of heterotrophic saprophytes, of proteolytic, amylolytic, and lipolytic bacteria as well as of ammonifying, nitrate reducing and anaerobic bacteria were determined on solid media and by MPN-tests. Metabolic activity was assessed by measuring enzyme activity of esterase, L-alanine-aminopeptidase, phosphatase, as well as of α- and β-glucosidase. Both biofilms revealed high population densities of bacteria from several metabolic groups as well as high enzyme activities. Their heterotrophic activity is in the range of or even higher than that found in high load activated sludges. The high activity of the bacterial biocenosis proves its resistance against high concentrations of chromium and nickel.

scholarly journals Stochastic calculus over symmetric Markov processes with time reversal

2015 ◽  
Vol 220 ◽  
pp. 91-148
Author(s):  
K. Kuwae
Keyword(s):  
Markov Processes ◽  
Time Reversal ◽  
Harmonic Functions ◽  
Stochastic Calculus ◽  
Additive Functional ◽  
Zero Energy ◽  
Additive Functionals ◽  
Stochastic Characterization ◽  
Symmetric Markov Processes

AbstractWe develop stochastic calculus for symmetric Markov processes in terms of time reversal operators. For this, we introduce the notion of the progressively additive functional in the strong sense with time-reversible defining sets. Most additive functionals can be regarded as such functionals. We obtain a refined formula between stochastic integrals by martingale additive functionals and those by Nakao's divergence-like continuous additive functionals of zero energy. As an application, we give a stochastic characterization of harmonic functions on a domain with respect to the infinitesimal generator of semigroup on L2-space obtained by lower-order perturbations.

A Modified Microtiter Plate Method for Biochemical Characterization of Listeria spp.

1991 ◽  
Vol 54 (2) ◽  
pp. 121-123 ◽  
Author(s):  
GREGORY R. SIRAGUSA ◽  
JERRY W. NIELSEN
Keyword(s):  
Biochemical Characterization ◽  
Microtiter Plate ◽  
Original Method ◽  
Bacterial Isolates ◽  
Plate Method ◽  
Solid Media ◽  
Us Fda ◽  
Term Storage ◽  
Microtiter Plate Format

A microtiter plate format previously reported for the biochemical characterization of microorganisms was modified by adding agar to all of the different test media instead of using a combination of liquid and solid media. This modification, termed the Modified Microtiter Plate procedure (MMP), offered the same advantages of the original method (labor saving, inexpensive, and custom designed for special needs) as well as having the added advantages of longer term storage prior to use and ease of handling. In this study, 60 bacterial isolates (both Listeria suspects and known Listeria cultures) were biotyped using the MMP protocol and compared to results obtained using the classical tube-based US-FDA recommended protocol as the standard identification method and the BBL-Minitek system.

scholarly journals Phenotypic and Transcriptional Characterization of the Meningococcal PhoPQ System, a Magnesium-Sensing Two-Component Regulatory System That Controls Genes Involved in Remodeling the Meningococcal Cell Surface

2005 ◽  
Vol 187 (14) ◽  
pp. 4967-4975 ◽  
Author(s):  
J. Newcombe ◽  
J. C. Jeynes ◽  
E. Mendoza ◽  
J. Hinds ◽  
G. L. Marsden ◽  
...  
Keyword(s):  
Cell Surface ◽  
Transcriptional Profiling ◽  
Regulatory System ◽  
Host Environment ◽  
Low Magnesium ◽  
System A ◽  
Solid Media ◽  
Two Component ◽  
Pathogenic Process

ABSTRACT We previously identified and characterized a two-component regulatory system in the meningococcus with homology to the phoP-phoQ system in salmonella and showed that allele replacement of the NMB0595 regulator gene led to loss of virulence, sensitivity to antimicrobial peptides, perturbed protein expression, and magnesium-sensitive growth. On the basis of these findings we proposed that the system should be designated the meningococcal PhoPQ system. Here we further characterized the NMB0595 mutant and demonstrated that it had increased membrane permeability and was unable to form colonies on solid media with low magnesium concentrations, features that are consistent with disruption of PhoPQ-mediated modifications to the lipooligosaccharide structure. We examined the transcriptional profiles of wild-type and NMB0595 mutant strains and found that magnesium-regulated changes in gene expression are completely abrogated in the mutant, indicating that, similar to the salmonella PhoPQ system, the meningococcal PhoPQ system is regulated by magnesium. Transcriptional profiling of the mutant indicated that, also similar to the salmonella PhoPQ system, the meningococcal system is involved in control of virulence and remodeling of the bacterial cell surface in response to the host environment. The results are consistent with the hypothesis that the PhoP homologue plays a role in the meningococcus similar to the role played by PhoP in salmonella. Elucidating the role that the PhoPQ system and PhoPQ-regulated genes play in the response of the meningococcus to the host environment may provide new insights into the pathogenic process.

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