scholarly journals A laboratory exposure system to study the effects of aging on super-micron aerosol particles

2014 ◽  
Author(s):  
Joshua Santarpia ◽  
Andres L. Sanchez ◽  
Gabriel Anthony Lucero ◽  
Brandon Lee Servantes ◽  
Joshua Allen Hubbard
Keyword(s):  
Aerosol Particles ◽  
Exposure System ◽  
Effects Of Aging ◽  
Laboratory Exposure

scholarly journals Transient and Sustained Bacterial Adaptation following Repeated Sublethal Exposure to Microbicides and a Novel Human Antimicrobial Peptide

2014 ◽  
Vol 58 (10) ◽  
pp. 5809-5817 ◽  
Author(s):  
Sarah Forbes ◽  
Curtis B. Dobson ◽  
Gavin J. Humphreys ◽  
Andrew J. McBain
Keyword(s):  
Antimicrobial Peptide ◽  
Biofilm Formation ◽  
Bacterial Isolates ◽  
Exposure System ◽  
Polyhexamethylene Biguanide ◽  
Prevention And Treatment ◽  
Before And After ◽  
The Stability ◽  
Induced Changes ◽  
Laboratory Exposure

ABSTRACTMicrobicides (biocides) play an important role in the prevention and treatment of infections. While there is currently little evidence for in-use treatment failures attributable to acquired reductions in microbicide susceptibility, the susceptibility of some bacteria can be reduced by sublethal laboratory exposure to certain agents. In this investigation, a range of environmental bacterial isolates (11 genera, 18 species) were repeatedly exposed to four microbicides (cetrimide, chlorhexidine, polyhexamethylene biguanide [PHMB], and triclosan) and a cationic apolipoprotein E-derived antimicrobial peptide (apoEdpL-W) using a previously validated exposure system. Susceptibilities (MICs and minimum bactericidal concentrations [MBCs]) were determined before and after 10 passages (P10) in the presence of an antimicrobial and then after a further 10 passages without an antimicrobial to determine the stability of any adaptations. Bacteria exhibiting >4-fold increases in MBCs were further examined for alterations in biofilm-forming ability. Following microbicide exposure, ≥4-fold decreases in susceptibility (MIC or MBC) occurred for cetrimide (5/18 bacteria), apoEdpL-W (7/18), chlorhexidine (8/18), PHMB (8/18), and triclosan (11/18). Of the 34 ≥4-fold increases in the MICs, 15 were fully reversible, 13 were partially reversible, and 6 were nonreversible. Of the 26 ≥4-fold increases in the MBCs, 7 were fully reversible, 14 were partially reversible, and 5 were nonreversible. Significant decreases in biofilm formation in P10 strains occurred for apoEdpL-W (1/18 bacteria), chlorhexidine (1/18), and triclosan (2/18), while significant increases occurred for apoEdpL-W (1/18), triclosan (1/18), and chlorhexidine (2/18). These data indicate that the stability of induced changes in microbicide susceptibility varies but may be sustained for some combinations of a bacterium and a microbicide.

A Novel Exposure System for the Efficient and Controlled Deposition of Aerosol Particles onto Cell Cultures

2008 ◽  
Vol 42 (15) ◽  
pp. 5667-5674 ◽  
Author(s):  
Melanie Savi ◽  
Markus Kalberer ◽  
Doris Lang ◽  
Manuel Ryser ◽  
Martin Fierz ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Aerosol Particles ◽  
Exposure System ◽  
Controlled Deposition

Carbonaceous particles and stone damage in a laboratory exposure system

1996 ◽  
Vol 101 (D14) ◽  
pp. 19621-19627 ◽  
Author(s):  
C. Sabbioni ◽  
G. Zappia ◽  
G. Gobbi
Keyword(s):  
Exposure System ◽  
Carbonaceous Particles ◽  
Laboratory Exposure

scholarly journals Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Mace G. Barron ◽  
Cheryl J. McGill ◽  
Lee A. Courtney ◽  
Dragoslav T. Marcovich
Keyword(s):  
Solar Radiation ◽  
Tissue Loss ◽  
Pocillopora Damicornis ◽  
Critical Research ◽  
Solar Simulator ◽  
Exposure System ◽  
Symbiotic Algae ◽  
Coral Reef Ecosystems ◽  
Radiation Treatments ◽  
Laboratory Exposure

Determining stressor-response relationships in reef building corals continues to be a critical research need due to global declines in coral reef ecosystems and projected declines for the future. A simplified recirculating coral exposure system was coupled to a solar simulator to allow laboratory testing of a diversity of species and morphologies of reef building corals under ecologically relevant conditions of temperature and solar radiation. Combinations of lamps and attenuating filters allowed for assignment of solar radiation treatments in experimental bleaching studies. Three bleaching experiments were performed using the reef building coral,Pocillopora damicornis, to assess the reproducibility of system performance and coral responses under control and stress conditions. Experiments showed consistent temperature- and solar radiation dependent-changes in pigment, numbers of symbiotic algae, photosystem II quantum yield, and tissue loss during exposure and recovery. The laboratory exposure system is recommended for use in experimental bleaching studies with reef building corals.

scholarly journals Les sénolytiques contre la Covid-19 ?

2021 ◽  
Vol 37 (11) ◽  
pp. 1062-1065
Author(s):  
Bertrand Jordan
Keyword(s):  
Clinical Trials ◽  
Viral Infection ◽  
Clinical Application ◽  
Phase Ii ◽  
Exposure System ◽  
Phase Ii Clinical Trials ◽  
Coronavirus Infection ◽  
Effects Of Aging ◽  
Old Mice ◽  
Ongoing Phase

The elimination of some senescent cells by « senolytic » compounds can greatly improve the health of aged mice and in some cases reverse the effects of aging. Using a microbial exposure system that closely models coronavirus infection, it is possible to largely protect old mice from the effects of viral infection. This immediately suggests clinical application of the approach, and is the aim of ongoing phase II clinical trials in Covid-19 patients.

Effects of aging on axon terminals in the dentate molecular layer

1987 ◽  
Vol 45 ◽  
pp. 928-929
Author(s):  
K. Cullen-Dockstader ◽  
E. Fifkova
Keyword(s):  
Granule Cells ◽  
Molecular Layer ◽  
Age Groups ◽  
Long Term Potentiation ◽  
Male Rats ◽  
Perforant Path ◽  
Axon Terminals ◽  
Fischer 344 ◽  
Spatial Memory Deficit ◽  
Effects Of Aging

Normal aging results in a pronounced spatial memory deficit associated with a rapid decay of long-term potentiation at the synapses between the perforant path and spines in the medial and distal thirds of the dentate molecular layer (DML), suggesting the alteration of synaptic transmission in the dentate fascia. While the number of dentate granule cells remains unchanged, and there are no obvious pathological changes in these cells associated with increasing age, the density of their axospinous contacts has been shown to decrease. There are indications that the presynaptic element is affected by senescence before the postsynaptic element, yet little attention has been given to the fine structure of the remaining axon terminals. Therefore, we studied the axon terminals of the perforant path in the DML across three age groups.5 Male rats (Fischer 344) of each age group (3, 24 and 30 months), were perfused through the aorta.

Effects of Aging on the Subcortical Encoding of Stop Consonants

2020 ◽  
Vol 29 (3) ◽  
pp. 391-403
Author(s):  
Dania Rishiq ◽  
Ashley Harkrider ◽  
Cary Springer ◽  
Mark Hedrick
Keyword(s):  
Older Adults ◽  
Repeated Measures ◽  
Mixed Model ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Aging Effects ◽  
Formant Frequency ◽  
Place Of Articulation ◽  
Second Formant ◽  
Effects Of Aging

Purpose The main purpose of this study was to evaluate aging effects on the predominantly subcortical (brainstem) encoding of the second-formant frequency transition, an essential acoustic cue for perceiving place of articulation. Method Synthetic consonant–vowel syllables varying in second-formant onset frequency (i.e., /ba/, /da/, and /ga/ stimuli) were used to elicit speech-evoked auditory brainstem responses (speech-ABRs) in 16 young adults ( M age = 21 years) and 11 older adults ( M age = 59 years). Repeated-measures mixed-model analyses of variance were performed on the latencies and amplitudes of the speech-ABR peaks. Fixed factors were phoneme (repeated measures on three levels: /b/ vs. /d/ vs. /g/) and age (two levels: young vs. older). Results Speech-ABR differences were observed between the two groups (young vs. older adults). Specifically, older listeners showed generalized amplitude reductions for onset and major peaks. Significant Phoneme × Group interactions were not observed. Conclusions Results showed aging effects in speech-ABR amplitudes that may reflect diminished subcortical encoding of consonants in older listeners. These aging effects were not phoneme dependent as observed using the statistical methods of this study.

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