Non-Newtonian Behavior of Blood in Oscillatory Flow

Sinusoidal oscillatory flow of blood and of aqueous glycerol solutions was produced in rigid cylindrical tubes. For aqueous glycerol, the amplitude of the measured pressure gradient wave form conformed closely to that predicted by Womersley's theory of oscillatory flow, up to Reynolds numbers approaching 2000. Blood differed significantly from aqueous glycerol solutions of comparable viscosity, especially at low frequencies and high hematocrits. As frequency increased, the hydraulic impedance of blood decreased to a minimum at a frequency of about 1-2 CPS, increasing monotonically at higher frequencies. The dynamic apparent viscosity of blood, calculated from Womersley's theory, decreased with increasing flow amplitude. The reactive component of the hydraulic impedance increased with frequency as predicted by theory; the resistive component decreased with increasing frequency, differing from the resistance of a Newtonian fluid which increased with frequency.     

ENDOMORPHIC AND ECTOMORPHIC CHARACTERS IN PELECYPHORA AND ENCEPHALOCARPUS

Boke , Norman H. (U. Oklahoma, Norman.) Endomorphic and ectomorphic characters in Pelecyphora and Encephalocarpus. Amer. Jour. Bot. 46(3) : 197-209. Illus. 1959.—Outstanding ectomorphic characters of Pelecyphora valdeziana include its small size; pectinate, hairy spines; broad, truncate, floral buds; dehiscent, berry-like fruits; and black, tuberculate seeds. The leaves are vestigial, and although the areole meristem originates on the adaxial face of the tubercle primordium, it is soon elevated to the summit by intercalary growth. The first primordium of the single, elliptical series of spines is initiated immediately in front of the rudimentary leaf. Others form in acropetal sequence on either side of the areole meristem. The last ones form across the areole, leaving a meristem, which may be floral or vegetative, on the anterior side. Whether areoles of P. valdeziana can be considered dimorphic is doubtful. However, they approach the type of dimorphism found in Epithelantha. Pelecyphora aselliformis has acuminate floral buds; dry, papery fruits; and brown, curved, reticulate seeds. The leaves are reduced almost to extinction. The areole meristem becomes separated into spiniferous and axial portions early in ontogeny, but the 2 parts remain connected by a band of trichomes, which probably represents a vestigial groove. The axial meristem may be reproductive or vegetative. The sequence of spine initiation in P. aselliformis is unusual in that it begins at the anterior side of the spiniferous meristem and proceeds toward the posterior side. Areoles in this species are clearly dimorphic, much as in the mammillarias, but the vestigial groove is reminiscent of Coryphantha and related genera. Although adult specimens of Encephalocarpus strobiliformis bear scale-like tubercles, which are very different from the laterally compressed tubercles of P. aselliformis, their flowers, fruits, and seeds are almost identical. The two species share the same type of areole dimorphism, including the vestigial groove. Tubercles on seedlings and young branches of E. strobiliformis are prismatic rather than scale-like. Since they tend to be laterally compressed at the summit and bear elliptical areoles with many more spines than the adult, they resemble seedling tubercles of P. aselliformis. Tubercles on adult specimens likewise resemble each other in the structure of the epidermis and hypodermis. It does not seem possible that P. valdeziana can be retained in the genus Pelecyphora. If seed structure has any systematic value, the species belongs in or near the genus Thelocactus, to which it was assigned by Bravo. Pelecyphora aselliformis and Encephalocarpus strobiliformis, on the other hand, share so many important characters that they could well be considered cogeneric. Both seed structure and the rudimentary grooves on the tubercles suggest that their affinities may lie with certain coryphanthas or mammillarias rather than with Ariocarpus and Epithelantha.     

Silver Protein Staining of Nerve Fibers in Celloidin Sections

Celloidin sections from formalin-fixed brain and spinal cord of primates are stored in 70% alcohol after cutting, soaked in 2% pyridine in 50% alcohol for 6-8 hr at 37 C, and transferred to 1% concentrated NH₄OH in 50% alcohol 15-18 hr at 20-25 C. After washing and flattening, the sections are transferred to 1% silver protein solution containing 30 ml of 0.2 M H₃BO₃/100 ml. Impregnation is accomplished in 50 ml screw-top jars, 50 mm in diameter, which are filled to a depth of 35 mm, and have 1 gm of copper foil, 0.002 inch thick added. The foil is folded in loose accordion-fashion, pierced and threaded, cleaned in 5% HNO₃, rinsed in distilled water, and suspended in the solution just above the sections by fastening the thread to the jar lid. The sections are impregnated for 24 hr at 37 C, rinsed in distilled water, reduced in a solution of 5% Na₂SO₃ and 1% hydroquinone for 10 min, washed in distilled water and toned in 0.2% gold chloride for 5 min. After rinsing in distilled water, the sections are transferred to 1% oxalic acid for 45-60 sec, washed in distilled water and placed in 5% Na₂S₂O₃ for 5 min. Sections are then washed, dehydrated to 95% alcohol, cleared in terpineol, followed by 3 changes in xylene, and mounted.     

Subtidal algal colonization following the removal ofEchinus

Summary 1. On the seaward face of Port Erin breakwater large algae do not occur on the lowest three metres. Here the density ofEchinus esculentus is high.2. Over a three year period allEchinus were removed from a 10 m wide strip at about monthly intervals. The total number of individuals removed approached 3000.3. One year after initial clearance the mean density ofLaminaria hyperborea sporelings on the strip was 22.7/m² and 5.1/m² to one side of it. By the winter these had almost disappeared outside the strip and in the succeeding years second and third year plants were found only on the strip or close to its edge. Other algae were similarly affected.4. It is concluded that the lower limit ofL. hyperborea is determined at least in part by the grazing pressure ofEchinus and that the urchins exercise some control over the numbers of other algae.

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Algenkolonisation im untergetauchten Gezeitenbereich nach Entfernung vonEchinus

Kurzfassung An der Sesseite des Port Erin Wellenbrecherdammes kommen keine größeren Algen im Bereich der unteren 3 m vor. Hier herrscht eine große Besiedlungsdichte des SeeigelsEchinus esculentus (3,6 Individuen pro m²). Über eine Zeitspanne von 3 Jahren wurden nun sämtlicheE. esculentus von einem 10 m breiten und 12 m langen Felsstreifen allmonatlich entfernt; insgesamt wurden dabei etwa 3000 Individuen abgesammelt. Ein Jahr nach Beginn des Absammelns betrug die mittlere Siedlungsdichte der jungenLaminaria hyperborea auf dem von Seeigeln freigehaltenen Felsstreifen 22,7/m². In den folgenden Jahren wurden zwei- und dreijährigeL. hyperborea nur auf diesem Felsstreifen oder in der Nähe seiner Begrenzungen gefunden. Andere Algenarten reagierten in ähnlicher Weise. Aus den Befunden wird gefolgert, daß die untere Verbreitungsgrenze vonL. hyperborea zumindest zum Teil durch Seeigelfraß bestimmt wird, und daßE. esculentus die Siedlungsdichte der anderen Algenarten beeinflußt.

     

A serological comparison of the three morphological phases of Coccidioides immitis; complement fixation tests with anti-Histoplasma capsulatum serum

Summary The results of this study indicated that antigens prepared from the three morphological phases ofCoccidioides immitis differed in their complement fixing activity with anti-Histoplasma capsulatum pooled serum. Spherule antigens were serologically less active in tests with the anti-H. capsulatum pooled serum than antigens prepared from arthrospores and from mycelium.Antigenic determinants which are common toC. immitis andH. capsulatum appeared to be located on the intact arthrospore cellular surface but not on the surface of spherule cells.Part of a dissertation submitted to the Graduate School of Duke University in partial fulfillment of requirements for the Ph. D. degree.This work was supported by contract with the Department of the Army, Fort Detrick, Frederick, Maryland.In conducting the research reported herein, the investigators adhered to Guide for Laboratory Animal Facilities and Care established by the Committee on the Guide for Laboratory Animal Facilities and Care of the Institute of Laboratory Animal Resources, NAS-NRC.