11,162 research outputs found
Electrochemical detection device
A standard pH reference electrode and a platinum cathodic electrode are positioned in a container with suitable nutrient medium for microbial growth plus the sample to be tested. The two electrodes are connected to electronic circuitry including an up/down counter whicn counts up for the first 80 minutes after a test has initiated. Then the potential between the two electrodes is tracked by the electronic circuitry and after there is a change of 10 mv a signal is sent to the up/down counter to cause it to reverse its count. When there is a additional 20 mv change in the potential between the two electrodes another signal is sent to the up/down counter, signalling it to stop. The resulting count on the counter is equal to the length of time for the inoculum to begin the production of measurable amounts of H2 after inoculation
Apparatus and process for microbial detection and enumeration
An apparatus and process for detecting and enumerating specific microorganisms from large volume samples containing small numbers of the microorganisms is presented. The large volume samples are filtered through a membrane filter to concentrate the microorganisms. The filter is positioned between two absorbent pads and previously moistened with a growth medium for the microorganisms. A pair of electrodes are disposed against the filter and the pad electrode filter assembly is retained within a petri dish by retainer ring. The cover is positioned on base of petri dish and sealed at the edges by a parafilm seal prior to being electrically connected via connectors to a strip chart recorder for detecting and enumerating the microorganisms collected on filter
Automated single-slide staining device
A simple apparatus and method is disclosed for making individual single Gram stains on bacteria inoculated slides to assist in classifying bacteria in the laboratory as Gram-positive or Gram-negative. The apparatus involves positioning a single inoculated slide in a stationary position and thereafter automatically and sequentially flooding the slide with increments of a primary stain, a mordant, a decolorizer, a counterstain and a wash solution in a sequential manner without the individual lab technician touching the slide and with minimum danger of contamination thereof from other slides
Microbiological surface sampling cart
Mobile sampling cart automatically swabs surfaces for the recovery of microorganisms. Unit operates without human involvement and provides for control of swabbing speed, rotation of cotton swab, and the pressure and angle applied to swab. Capability of reverse direction is also available. Sampling cart use is limited to flat surfaces
Simple chamber facilitates chemiluminescent detection of bacteria
Test chamber enables rapid estimation of bacteria in a test sample through the reaction of luminol and an oxidant with the cytochrome C portion of certain species of bacteria. Intensity of the light emitted in the reaction is a function of the specific bacteria in the test sample
Automatic microbial transfer
Device can transfer metabolites or inhibitory agents to broth cultures of bacteria, in various stages of growth, for study. It also has application in transfer of other micro-organisms, such as yeasts, and could be useful in clinical and research laboratories. Device has been used for wide variety of purposes in experimental situations
Driving extreme variability: The evolving corona and evidence for jet launching in Markarian 335
Variations in the X-ray emission from the narrow line Seyfert 1 galaxy,
Markarian 335 (Mrk 335), are studied on both long and short timescales through
observations made between 2006 and 2013 with XMM-Newton, Suzaku and NuSTAR.
Changes in the geometry and energetics of the corona that give rise to this
variability are inferred through measurements of the relativistically blurred
reflection seen from the accretion disc. On long timescales, we find that
during the high flux epochs the corona has expanded, covering the inner regions
of the accretion disc out to a radius of 26(-7,+10)rg. The corona contracts to
within 12rg and 5rg in the intermediate and low flux epochs, respectively.
While the earlier high flux observation made in 2006 is consistent with a
corona extending over the inner part of the accretion disc, a later high flux
observation that year revealed that the X-ray source had become collimated into
a vertically-extended jet-like corona and suggested relativistic motion of
material upward. On short timescales, we find that an X-ray flare during a low
flux epoch in 2013 corresponded to a reconfiguration from a slightly extended
corona to one much more compact, within just 2~3rg of the black hole. There is
evidence that during the flare itself, the spectrum softened and the corona
became collimated and slightly extended vertically as if a jet-launching event
was aborted. Understanding the evolution of the X-ray emitting corona may
reveal the underlying mechanism by which the luminous X-ray sources in AGN are
powered.Comment: 21 pages, 9 figures. Accepted for publication in MNRA
Apparatus for microbiological sampling
An automatic apparatus is described for microbiologically sampling surface using a cotton swab which eliminates human error. The apparatus includes a self-powered transport device, such as a motor-driven wheeled cart, which mounts a swabbing motor drive for a crank arm which supports a swab in the free end thereof. The swabbing motor is pivotably mounted and an actuator rod movable responsive to the cart traveling a predetermined distance provides lifting of the swab from the surface being sampled and reversal of the direction of travel of the cart
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