Daniel A. Porter

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Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response,(More)
In vitro perifusion was employed to compare the potencies of mammalian, avian, salmon, and lamprey gonadotropin-releasing hormones (GnRHs) on the release of luteinizing hormone (LH) from the pituitaries of an amphibian (Rana pipiens) and a reptile (Chrysemys picta). The chicken-I and salmon GnRH variants were equipotent with mammalian GnRH in both the frog(More)
Dynamics of pituitary responsiveness to gonadotropin-releasing hormone (GnRH) as measured by LH and FSH secretion rates were examined for two species of ranid frogs in an in vitro superfusion system. The influence of sex was studied with juvenile bullfrogs, Rana catesbeiana, and responsiveness to long-term continuous superfusion with GnRH was examined in R.(More)
The luteinizing hormone (LH) surge initiates the final stages of ovarian follicle development, and induces ovulation and luteinization of preovulatory follicles. To investigate whether exposure to the LH surge alters follicle cell susceptibility to apoptosis, granulosa and theca cells were isolated from bovine preovulatory follicles before and 14 h after(More)
Introduction: Diffusion-weighted, readout-segmented EPI (rs-EPI) with parallel imaging and 2D navigator correction [1] can provide substantially improved image quality compared to single-shot EPI (ss-EPI) with parallel imaging. The technique achieves a reduction in susceptibility artefacts and T 2 * image blurring by allowing a very short echo-spacing,(More)
PURPOSE To look at the presenting features, Enneking stage, size of primary tumour, method of treatment and patient and doctor delays in upper extremity Ewing's sarcoma to observe the effects on local recurrence, metastasis and survival. PATIENTS AND METHODS Nineteen patients with upper extremity Ewing's sarcoma were identified using the Scottish Bone(More)
FOREWORD This paper has been written in honour of the lamented Raymond Rogers who first proposed this work and dedicated many hours of his life to improve this collection of information; he wrote: " No matter what the truth is about the Shroud, it is a fascinating study. It can be studied according to the rigorous Scientific Method, and it is too bad that(More)
The roles of K+, Ca2+, and Na+ ions in the mechanism of gonadotropin releasing hormone (GnRH) action on frog (Rana pipiens) hemipituitaries were studied using an in vitro superfusion system. The effects of elevated K+ alone or in combination with Ca2+-depleted medium, tetrodotoxin (TTX), or with 100 ng/ml GnRH were examined. The involvement of K+ was also(More)
A superfusion system was employed to study the dynamics of the responses of LH secretion to gonadotropin releasing hormone (GnRH) by anterior pituitary glands (quartered) from adult turtles, Pseudemys scripta and Chrysemys picta. Responsiveness was highly variable in both species, but in many cases, the tissues showed marked responses to relatively low(More)
Droplet breakup of many Newtonian fluids is well described by current experiments, theory, and simulations. Breakup in complex fluids where interactions between mesoscopic structural features can affect the flows remains poorly understood and a burgeoning area of research. Here, we report on our investigations of droplet breakup in thermotropic liquid(More)
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