Twenty-six strains of 22 bacterial species were tested for growth on trypticase soy agar (TSA) or sea-salt agar (SSA) under hypobaric, psychrophilic, and anoxic conditions applied singly or in combination. As each factor was added to multi-parameter assays, the interactive stresses decreased the numbers of strains capable of growth and, in general, reduced the vigor of the strains observed to grow. Only Serratia liquefaciens strain ATCC 27592 exhibited growth at 7 mbar, 0°C, and CO2-enriched anoxic atmospheres. To discriminate between the effects of desiccation and hypobaria, vegetative cells of Bacillus subtilis strain 168 and Escherichia coli strain K12 were grown on TSA surfaces and simultaneously in liquid Luria-Bertani (LB) broth media. Inhibition of growth under hypobaria for 168 and K12 decreased in similar ways for both TSA and LB assays as pressures were reduced from 100 to 25 mbar. Results for 168 and K12 on TSA and LB are interpreted to indicate a direct low-pressure effect on microbial growth with both species and do not support the hypothesis that desiccation alone on TSA was the cause of reduced growth at low pressures. The growth of S. liquefaciens at 7 mbar, 0°C, and CO2-enriched anoxic atmospheres was surprising since S. liquefaciens is ecologically a generalist that occurs in terrestrial plant, fish, animal, and food niches. In contrast, two extremophiles tested in the assays, Deinococcus radiodurans strain R1 and Psychrobacter cryohalolentis strain K5, failed to grow under hypobaric (25 mbar; R1 only), psychrophilic (0°C; R1 only), or anoxic (< 0.1% ppO2; both species) conditions.
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http://dx.doi.org/10.1089/ast.2011.0811 | DOI Listing |
Am J Ophthalmol
December 2024
Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA. Electronic address:
Purpose: Primarily, to evaluate the repeatability and reproducibility of the new non-contact esthesiometer (NCE) in healthy subjects. Secondarily, the corneal sensitivity threshold measurements of the NCE were compared with those of the Cochet-Bonnet esthesiometer (CBE).
Design: Assessment reliability study.
Functionalization and volatilization are competing reactions during the oxidation of carbonaceous materials and are important processes in many different areas of science and technology. Here, we present a combined ambient pressure X-ray photoelectron spectroscopy (APXPS) and grazing incidence X-ray scattering (GIXS) investigation of the oxidation of oleic acid ligands surrounding NaYF nanoparticles (NPs) deposited onto SiO/Si substrates. While APXPS monitors the evolution of the oxidation products, GIXS provides insight into the morphology of the ligands and particles before and after the oxidation.
View Article and Find Full Text PDFJ Environ Manage
December 2024
State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, Harbin, 150090, China.
The gravity-driven membrane (GDM) system is an energy-efficient and environmentally sustainable water purification process; however, after prolonged operation, its membrane flux remains relatively low, making it necessary to adopt effective strategies for improving system performance. In this study, the effects of hydrostatic pressure (60, 100, 200 mbar) and pre-coating with aluminum-based flocs (ABF) on GDM flux and organic matter removal were investigated, and the regulatory mechanisms of the bio-cake layer were explored through interactions between morphological structure, composition and microbes. The results showed that the stable flux of the GDM-ABF system at a hydrostatic pressure of 60 mbar was almost equal to that at 100 mbar, and it outperformed higher hydrostatic pressure in organic matter removal, resulting in a more porous bio-cake layer structure.
View Article and Find Full Text PDFLab Chip
December 2024
Sensors and Devices Center, Bruno Kessler Foundation, Via Sommarive 18, 38123 Trento, Italy.
Microneedles hold the potential for enabling shallow skin penetration applications where biomarkers are extracted from the interstitial fluid (ISF) and drugs are injected in a painless and effective manner. To this purpose, needles must have an inner channel. Channeled needles were demonstrated using custom silicon microtechnology, having several needle tip geometries.
View Article and Find Full Text PDFRev Sci Instrum
December 2024
Max-Planck-Insitut für Plasmaphysik, Boltzmannstrasse 2, Garching D-85748, Germany.
The Testbed for Analysis of Permeation of Atoms in Samples (TAPAS) is an experimental setup for ion-driven permeation studies with a focus on investigating wall materials for nuclear fusion devices. A monoenergetic, mass-filtered high-intensity keV ion beam is focused and directed onto the permeation sample by electrostatic ion optics and decelerated to the desired ion energy by a dedicated set of apertures close to the sample. We were able to obtain ion energies as low as 170 eV/D with a D3+ ion beam with an ion flux density of the order of 1020 D/m2s on a beam-wetted area of ∼33 mm2.
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