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Articles 1 - 9 of 9

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Behavioral, Neurophysiological And Evolutionary Perspectives On Unihemispheric Sleep, Niels Rattenborg, Charles Amlaner, Steven Lima Nov 2000

Behavioral, Neurophysiological And Evolutionary Perspectives On Unihemispheric Sleep, Niels Rattenborg, Charles Amlaner, Steven Lima

Charles J. Amlaner

Several animals mitigate the fundamental conflict between sleep and wakefulness by engaging in unihemispheric sleep, a unique state during which one cerebral hemisphere sleeps while the other remains awake. Among mammals, unihemispheric sleep is restricted to aquatic species (Cetaceans, cared seals and manatees). in contrast to mammals, unihemispheric sleep is widespread in birds, and may even occur in reptiles. Unihemispheric sleep allows surfacing to breathe in aquatic mammals and predator detection in birds. Despite the apparent utility in being able to sleep unihemispherically, very few mammals sleep in this manner. This is particularly interesting since the reptilian ancestors to mammals ...


Method And Apparatus For Adaptive Filtering By Counting Acoustic Sample Zeroes In Ultrasound Imaging, Gregory R. Bashford, Edward D. Nonnweiler, David D. Becker, David John Muzilla Oct 2000

Method And Apparatus For Adaptive Filtering By Counting Acoustic Sample Zeroes In Ultrasound Imaging, Gregory R. Bashford, Edward D. Nonnweiler, David D. Becker, David John Muzilla

Biomedical Imaging and Biosignal Analysis Laboratory

An ultrasound imaging system having an adaptive spatial filter the filter coefficients of which, for particular image parameter sample, are determined by counting the number of neighboring image parameter samples having zero or near-zero values. If the number of zero or near-zero values in a data window is greater than a predetermined threshold, the data in the window is passed, not filtered. This filter has two advantages over other spatial filters. First, image parameter data samples having only zero or near-zero neighboring values (i.e., isolated "point noise") are not smeared. Second, boundaries such as the edge of color in ...


Eye States And Postures Of The Western Fence Lizard (Sceloporus Occidentalis), With Special Reference To Asynchronous Eye Closure And Behavioral Sleep, Christian Mathews, Charles Amlaner Aug 2000

Eye States And Postures Of The Western Fence Lizard (Sceloporus Occidentalis), With Special Reference To Asynchronous Eye Closure And Behavioral Sleep, Christian Mathews, Charles Amlaner

Charles J. Amlaner

No abstract provided.


Method And Apparatus For Controlling Acoustic Signal Bandwidth In An Ultrasonic Diagnostic Imaging System, Jeffrey R. Resnick, Gregory R. Bashford Jun 2000

Method And Apparatus For Controlling Acoustic Signal Bandwidth In An Ultrasonic Diagnostic Imaging System, Jeffrey R. Resnick, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

An ultrasonic imaging system includes a receive beamformer that generates analog receive signals and a scan converter. A receive signal processing path interconnects the receive beamformer and the scan converter, and this processing path included both an A/D converter characterized by a selectable sampling rate and at least one filter characterized by at least one filter parameter. The filter parameter is selected as a function of the sampling rate to provide enhanced image quality.


Method And Apparatus For Three-Dimensional Ultrasound Imaging Of Biopsy Needle, Syed Omar Ishrak, Mir Said Seyed-Bolorforosh, William Thomas Hatfield, Todd Michael Tillman, Brian Peter Geiser, Gregory R. Bashford, Michael Joseph Washburn Apr 2000

Method And Apparatus For Three-Dimensional Ultrasound Imaging Of Biopsy Needle, Syed Omar Ishrak, Mir Said Seyed-Bolorforosh, William Thomas Hatfield, Todd Michael Tillman, Brian Peter Geiser, Gregory R. Bashford, Michael Joseph Washburn

Biomedical Imaging and Biosignal Analysis Laboratory

A method and an apparatus for three-dimensional ultrasound imaging of a needle-like instrument, such as a biopsy needle, inserted in a human body. The instrument is visualized by transmitting ultrasound beams toward the instrument and then detecting the echo signals using a linear array of transducer elements. The problem of ultrasound being reflected from a biopsy needle in a direction away from the transducer array is solved by steering the transmitted ultrasound beams t increase the angle at which the beams impinge upon the biopsy needle. Ideally the ultrasound beams are perpendicular to the needle. This increases the system's ...


The Effects Of Estradiol And Progresterone On The Media Collateral Ligament Of Prepubescent Rats, Nicolle Kahl Apr 2000

The Effects Of Estradiol And Progresterone On The Media Collateral Ligament Of Prepubescent Rats, Nicolle Kahl

Life and Environmental Sciences Undergraduate Theses

Recent studies of female athletes have shown that females are more prone to knee injuries than their male counterparts. This phenomenon has been attributed to several factors including anatomical structure differences such as quadriceps-hamstring imbalances, type of activity (specifically cutting and planting motions), use of braces, and hormonal differences. It is known that hormones like relaxin have an obvious effect on ligament composition, but the effects of other hormones on ligaments has yet to be fully determined. One particular study reported that a female is most susceptible to knee injuries during the pre-ovulatory phase of her cycle, when estrogen levels ...


Endocrine Responses To Chronic Androstenedione Intake In 30- To 56-Year-Old Men, Gregory A. Brown, Matthew D. Vukovich, Emily R. Martini, Marian L. Kohut, Warren D. Franke, David A. Jackson, Douglas S. King Jan 2000

Endocrine Responses To Chronic Androstenedione Intake In 30- To 56-Year-Old Men, Gregory A. Brown, Matthew D. Vukovich, Emily R. Martini, Marian L. Kohut, Warren D. Franke, David A. Jackson, Douglas S. King

Warren D Franke

In young men, chronic ingestion of 100 mg androstenedione (ASD), three times per day, does not increase serum total testosterone but does increase serum estrogen and ASD concentrations. We investigated the effects of ASD ingestion in healthy 30- to 56-yr-old men. In a double-blind, randomly assigned manner, subjects consumed 100 mg ASD three times daily (n 5 28), or placebo (n 5 27) for 28 days. Serum ASD , dihydrotestosterone (DHT), free and total testosterone, estradiol, prostate-specific antigen (PSA), and lipid concentrations were measured at week 0 and each week throughout the supplementation period. Serum total testosterone and PSA concentrations did ...


Expression Of Bovine Mammary Gland Ca2+Atpases , Siriwan Prapong Jan 2000

Expression Of Bovine Mammary Gland Ca2+Atpases , Siriwan Prapong

Retrospective Theses and Dissertations

Control of transcellular Ca2+ fluxes associated with lactation are critical to mammary function and Ca2+ homeostasis. Mammary Ca2+ transport and storage may contribute to the pathological hypocalcemia seen in dairy cows at parturition. RT-PCR and Western Blotting were used to identify which Ca2+ ATPases are present in the bovine mammary gland and in milk fat globule membranes (MFGM). PMCA1, PMCA2 and PMCA4 are plasma membrane Ca2+ ATPases expressed in the bovine mammary gland. A putative Golgi Ca2+ ATPase (bSPCA) is also found in significant amounts in the mammary gland. The expression of Ca2+ ATPases in the bovine mammary gland is ...


Characterization Of [Alpha]-Adrenoceptor-Mediated Contractile Responses In The Isolated Bovine Tail Artery And Vein And An Investigation Of Nerve-Mediated Contraction In The Bovine Tail Artery In Response To Electrical Field Stimulation , Marina Val Ioudina Jan 2000

Characterization Of [Alpha]-Adrenoceptor-Mediated Contractile Responses In The Isolated Bovine Tail Artery And Vein And An Investigation Of Nerve-Mediated Contraction In The Bovine Tail Artery In Response To Electrical Field Stimulation , Marina Val Ioudina

Retrospective Theses and Dissertations

The purpose of this study was to identify alpha-adrenoreceptor types and subtypes mediating contractile responses to adrenergic agonists in the bovine tail artery and vein and to investigate nerve-mediated contraction in the bovine tail artery in response to electrical field stimulation. Isolated tissue bath methods were used to study isometric contractile responses in vessel rings. Electrical field stimulation, under constant current conditions, was used to study vessel contraction as a result of neurotransmitter(s) release from sympathetic nerve terminals;Evidence was obtained for the presence of functional alpha1A- and alpha1D-adrenoceptors in the tail artery. Whether functional alpha 1B-adrenoceptors are present ...