Insights Into Elevated Distortion Product Otoacoustic Emissions In Sickle Cell Disease: Comparisons of Hydroxyurea-treated and Non-treated Young Children

Distortion product otoacoustic emissions (DPOAEs) were examined in 15 normal- hearing African-American children between the ages of 6 and 14 years with homozygous sickle cell disease (SCD), who were on a regimen of hydroxyurea (HDU), a drug that reduces inflammatory processes and symptoms of SCD; a matched group of 15 African- American children with homozygous SCD not on HDU; and 15 African-American children with normal hemoglobin. DPOAEs were evoked by 13 primary tone pairs with f2 frequencies ranging from 1000 to 4500 Hz. Increased DPOAE amplitudes, believed to be a precursor of eventual hearing loss, were evident in children with SCD who were not receiving HDU. Those taking HDU had DPOAE amplitudes similar to normal controls. These findings suggest that HDU, in addition to reducing symptoms of SCD, may play a role in inhibiting or preventing cochlear pathology and hearing loss in individuals with SCD. Key Words: distortion product otoacoustic emissions; sickle cell disease; hydroxyurea Abbreviations: ABR = auditory brainstem response; DPOAE = distortion product otoacoustic emission; HDU = hydroxyurea; HbSS = homozygous sickle cell disease; ICAM = intercellular adhesion molecule; M = mean; OAE = otoacoustic emission; p = probability; PECAM = platelet-endothelial cell adhesion molecule SCD = sickle cell disease; SD = standard deviation of the mean; SOAE = spontaneous otoacoustic emission; TEOAE = transient evoked otoacoustic emission; VCAM = vascular cell adhesion molecule

Exploring the silicification of microbes and understanding their role in the fossil record

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020Cataloged from the official PDF of thesis.Includes bibliographical references (pages [24]-[29]).Filamentous cyanobacteria that built macroscopic tufted mats in Proterozoic peritidal environments were fossilized by silicification, but the environmental and biological factors that shaped these structures and enabled this type of preservation are not well understood. Recent work has shown that coccoidal cyanobacteria can become fossilized because they can sequester silica from seawater that is undersaturated with respect to silica. Here, we use taphonomy experiments to demonstrate that filamentous cyanobacteria that form tufted and conical mats are also able to mediate the precipitation of silica in seawater that is undersaturated with respect to silica as well. These results show that different marine cyanobacteria and their macroscopic structures have a high potential to be preserved by silicification. We find that the exterior of macroscopic structures such as tufts and pillars are preferentially silicified, and more completely silicified at silica concentrations below saturation in seawater. The interior of these structures may be preserved by later diagenetic minerals. These results are consistent with microfossil assemblages found in early diagenetic chert deposits throughout the Proterozoic. The data suggest abundant Ca-rich sulfated polysaccharides in the exopolymeric substance (EPS), which are likely the site of silicification. Interactions among similar organisms, seawater chemistry, and silica in evaporative environments may account for the two-billion-year long record of exceptionally silicified filamentous and coccoidal cyanobacteria and their macroscopic aggregates in peritidal environments.by Kyle J. Morgenstein.S.B.S.B. Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Science

Reviews

Review of Dating Techniques for the Archaeologist, by Henry N. Michael and Elizabeth K. Ralph (eds.); Explanation in Archaeology, by Patty Jo Watson, Steven A LeBlanc, and Charles Redman; Frozen Tombs of Siberia, by Sergei I. Rudenko; The Early History of Korea, by K. J. H. Gardiner; Zur Chronologie der fruhsillazeitlichen Graber in Sudkorea, by Akio Ito; Japanes Mythology, by Juliet Piggott; Cultural Frontiers in Ancient East Asia, by William Watson; Arts of China, by Terukazu Akiyama and Saburo Matsubara; Agricultural Development in China 1368-1968, by Dwight H. Perkins; Trade and Expansion in Han China, by Ying-shih Yu; The Transformation of the Chinese Earth, by Keith Buchanan; Stone Adzes of Southeast Asia, by Roger Duff; Archaeological Excavations in Thailand, Volume III, part two, by Sood Sangvichien, Patai Sirigaroon, J. Balslev Jorgensen and Teuku Jacob; Religioses Leben der Sherpa, by Friedrich W. Funke; Pre- and Proto-History of the Berach Basin, South Rajasthan, by V. N. Misra; Archeologie des Hautes-Terres et de l'Afrique-Orientale: Anthropologie; Oriental Ceramics Discovered in the Philippines, by Leandro Locsin and Cecelia Locsin; The Tabon Caves, by Robert B. Fox; Dog and Man in the Ancient Pacific with Special Attention to Hawaii, by Margaret Titcomb; Studies in Oceanic Culture History Volume 1, by R. C. Green and M. Kelly (eds.); Bernice P. Bishop Museum, Department of Anthropology Report Series; Pacific Anthropological Records, numbers 6, 7, 8, 9; Makaha Valley Historical Project: Interim Report No. 2, by Roger C. Green (ed.); Australian Aboriginial Anthropology, by Ronald M. Berndt (ed.); Man, Land and Myth in North Australia, by Ronald M. Berndt and Catherine H. Berndt; Burrill Lake and Currarong, by R. J. Lampert; Diprotodon to Detribalization, by Arnold R. Pilling and Richard A. Waterman (eds.); The Prehistory of Australia, by D. J. Mulvaney; The Aborigines of Tasmania, by H. Ling Roth

Mycoplasmal mastitis in dairy herds

This paper addresses two main issues of the DOK system [15], that is the design of a framework for enforcing security policies and a secure architecture which implements such a framework. Federated security policies are expressed as logic-based expressions (called "aggregation constraints") specifying the different combinations of transactions that a user is not allowed to issue, either in single or multiple states of a federation. To enable efficient monitoring of aggregation constraints, state transition graphs are generated to model the different sub-computations of the constraints. Two marking techniques, namely LMT (Linear Marking Technique) and ZMT (Zigzag Marking Technique), are proposed to detect violations of federated security policies. To enable an effective enforcement of security policies, we designed a secure DOK architecture using specialised agents: (i) coordination agents allow the coordination of different federated activities, (ii) task agents perform specific tasks of th..

Minimally invasive management of bile leak after laparoscopic cholecystectomy

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