Evaporative Water Losses of Some Small Australian Lizards

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/119114/1/ecy1966474589.pd

Search for plant biomagnetism with a sensitive atomic magnetometer

We report what we believe is the first experimental limit placed on plant biomagnetism. Measurements with a sensitive atomic magnetometer were performed on the Titan arum (Amorphophallus titanum) inflorescence, known for its fast bio-chemical processes while blooming. We find that the surface magnetic field from these processes, projected along the Earth's magnetic field, and measured at the surface of the plant, is less then ~0.6uG.Comment: 5 pages, 5 figures, to be published - modified one sentence in abstract + reformatted fi

Synthesis and Electrochemical Behavior of Nanostructured Copper Particles on Graphite for Application in Lithium Ion Batteries

Graphitic materials are currently the state-of-the-art anode materials for lithium ion secondary batteries. By chemical modification, the electrochemical performance of the pristine materials can be improved. In this paper we report on the preparation of nanostructured copper particles on graphite by thermal decomposition of copper formate. With this technique a novel, simple and low cost method for a homogeneous deposition of nanostructured copper particles on graphite was established. Different amounts of copper were realized and their influence on the electrochemical behavior of the active material was investigated. The copper particles had a size distribution between 50 nm and 300 nm. Electrochemical measurements displayed an improved performance of the synthesized composite material compared to the pristine material. Cyclic voltammetry showed a suppressed cointercalation of solvated lithium and an increased formation of the solid electrolyte interphase (SEI). Battery cycling demonstrated an increased discharge capacity and cycling stability. © 2015 Walter de Gruyter

Competition for the in vitro binding of radioiodinated human follicle-stimulating hormone in reptilian, avian, and mammalian gonads by nonmammalian gonadotropins

Radioiodinated human FSH (125I-hFSH) was used to study the specificity of the gonadotropin binding sites of various reptilian, avian, and mammalian gonadal tissues by examining competitive interactions with several nonmammalian gonadotropins. All preparations of nonmammalian gonadotropins showed some activity in these radioligand assays, but wide variations in activities were evident depending on the source of the tissue and source of the hormone. Several cases of marked species specificity in binding were apparent: Nonmammalian hormones were relatively inactive with porcine granulosa cells; frog and snake hormones were relatively inactive in turtle tissues; and frog hormones were essentially inactive in avian tissues. FSH-LH specificity of binding determined with hormones of nonmammalian origin differed significantly from that previously described with the aid of mammalian gonadotropins. In particular, when tested with some tissues, three preparations of LH, from the turkey, sea turtle, and frog, were in some cases more active in competing for 125I-hFSH binding than preparations of FSH from the same species; this activity could not be readily accounted for by FSH contamination. These comparative data demonstrate the existence of considerable overlap in the binding characteristics of some species of FSH and LH; the observed differences probably reflect evolutionary changes in both gonadotropin binding sites and in the structure of the gonadotropins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21644/1/0000028.pd

Thermal dependence of water and electrolyte excretion in two species of lizards

1. 1. Lizards with different preferred temperatures were water-loaded, and their ability to excrete excess water and conserve electrolytes was tested at several temperatures.2. 2. Rates of water excretion were much less temperature dependent in lizards having a low preferred temperature, but were maximal at about 30-35[deg]C in both species.3. 3. Urinary sodium levels were minimal at temperatures near the respective preferred temperature of each species.4. 4. Urinary potassium levels were low and apparently not temperature dependent over most of the range studied, but increased as lethal temperatures were approached.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33276/1/0000668.pd

Seasonal cycles in testicular activity, gonadotropin, and thyroxine in the painted turtle, Chrysemys picta, under natural conditions

Plasma levels of testosterone (T), thyroxine (T4) and follicle-stimulating hormone (FSH) were measured in a field population of the painted turtle, Chrysemys picta, in Michigan. All three hormones showed pronounced seasonality; plasma luteinizing hormone (LH) remained nondetectable. Plasma T and FSH concentrationswere highly correlated and exhibited biphasic cycles with peaks in spring and fall, whereas T4 showed a single peak in summer, coincident with the nadir in T. Hormone levels were minimal on the day that animals emerged from hibernation at the end of March; T and FSH then increased rapidly (in ca. 1 week after emergence) to a transient peak that persisted for onlyca. 2 weeks. Plasma T and FSH rose again in September before the onset of hibernation and shortly after the late summer peak in spermatogenetic recrudescence. Plasma T4 increased more gradually after emergence in spring and did not peak for 1-2 months, coincident with the nadir in T. The profile in plasma FSH is consistent with the view that this gonadotropin may regulate androgen secretion but it did not show the expected relationship to the spermatogenetic cycle. Separate studies indicated that the turtles are sensitive to capture and handling; hormone levels (especially androgen) fall precipitously within a day of capture. These "stress" effects may account for discrepancies with previous studies of plasma T in this species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25629/1/0000179.pd

Thermal adjustments in cardiac and skeletal muscles of lizards

1. Isometric twitch tension development was measured over a wide range of temperatures in skeletal and cardiac (ventricular) muscles from diverse Australian lizards representing several families and including both diurnal and nocturnal species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47099/1/359_2004_Article_BF00297986.pd

The temperature dependence of myosin-adenosinetriphosphatase and alkaline phosphatase in lizards,

1. 1. The temperature dependence of myosin ATP-ase and intestinal alkaline phosphatase from a variety of lizards having distinct preferred temperatures was compared.2. 2. The ATP-ase was relatively thermolabile; reductions in activity at temperatures above the optimum resulted primarily from irreversible denaturation. However, pronounced differences were evident in both the optimal temperatures and thermostabilities of the ATP-ases from eight species of lizards. Optima ranged from 33-42[deg]C.3. 3. Alkaline phosphatase was more heat resistant and reductions in activity above the optimum were largely reversible. There was virtually no difference in the temperature dependence of the alkaline phosphatase from four species studied. The optimal temperature for this enzyme was about 42[deg]C and no denaturation was evident at 51[deg]C.4. 4. Differences in the temperature dependence of the ATP-ase correlated well with differences in the preferred temperatures of the respective species. Thus, biochemica; adjustments in ATP-ase appear to be closely associated with thermal adaptations evident at the level of the whole animal; but it is clear that not all enzymes are similarly involved in organismal thermal adjustments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32116/1/0000166.pd