Loss of glucose transport in developing avian red cells

OBJECTIVE: This study aimed to examine the characteristics of intraretinal changes associated with macular holes and epiretinal membranes by scanning retinal thickness analysis. STUDY DESIGN: The study design was a nonconsecutive case series. PATIENTS: Fifty-six eyes of patients who had either a suspected or clinically diagnosed macular hole or epiretinal membrane were recruited. INTERVENTIONS: A commercial prototype of the scanning retinal thickness analyzer (RTA) was used. It projected a laser slit beam onto the retina and scanned it, in 200 or 400 msec, across a 2- x 2-mm area, yielding multiple optical cross sections that were recorded digitally. RESULTS: Epiretinal membranes were detected, and sites of attachment could be identified. Full-thickness holes corresponded to intraretinal cavities in which the inner retinal surface was broken, usually at the center. The majority of eyes with full-thickness macular holes showed increased retinal thickness surrounding the hole. The so-called "cuff of subretinal fluid," however, often was not present by retinal thickness analysis, despite clinical diagnosis to the contrary, even though retinal thickness analysis is capable of detecting such fluid. In 20 (42%) of 47 eyes diagnosed or suspected of having macular holes, scanning retinal thickness analysis showed findings different from those reported by retinal specialists. CONCLUSIONS: Examination of macular holes with the scanning RTA provides useful information in the diagnosis of macular holes in addition to that obtained through conventional techniques. The findings support the idea that many macular holes develop in association with intraretinal cystic changes. The precise chronology of the events remains to be determined.     

Connecting levels of activity with classroom network technology

Classroom activity traditionally takes one of three forms, variously oriented toward the levels of individual students, small groups, or the whole class. CSCL systems, however, may enable novel ways to facilitate instruction within or sequence activity across these different levels. Drawing on theoretical accounts of learning at and across different scales of social interaction, this paper examines episodes of classroom activity featuring two learning environment designs that leverage networked digital devices to support face-to-face collaboration. Analysis of these episodes focused on two questions: When did activity shift between small and whole-group levels, and what mechanisms enabled or supported those shifts? Findings suggest that classroom activity in these environments was sometimes characterized by frequent, rapid shifts between levels, as well as instances that suggested hybrid forms of small-group and whole-class interaction. These shifts between and overlaps across levels were enabled and sustained through mechanisms including teacher orchestration, mediating roles played by virtual mathematical objects, learners’ appropriation of shared artifacts and resources, and emergent properties of these complex interactions among classroom participants.     

Analysis of Protective Behavior and Security Incidents for Home Computers

This study analyzes the factors that affect security protective behavior and perceived security incidents. Protective behavior is found to have a positive impact on the perceived security incidents, especially for the more educated home computer user. Human factors such as “perceived barriers” (to use new security software tools), “self-efficacy” (confidence), and “cues to action” (awareness) are found to influence both the protective behavior and perceived security incidents.     

Dynamic fatigue of a hot glass-ceramic

The structures of crystalline silicates are characteristically of low symmetry and large lattice parameters, neither of which feature is conducive to easy plastic deformation by dislocation mechanisms. Non-crystalline silicates, on the other hand, are usually Newtonian fluids at high temperatures and it is flow of the non-crystalline material which is believed to be responsible for the plasticity of hot glass-ceramics. The high temperature dynamic fatigue properties of a Li₂O-ZnO-SiO₂ glass-ceramic have been investigated in order to test ideas suggested by tests previously carried out on the same material at constant stresses and at constant strain-rates.     

A basic experimental study of sandwich injection molding with sequential injection

An experimental study of sandwich injection molding is reported which involves sequential injection of polymer melts with differing melt viscosity into a mold. In isothermal injection molding the relative viscosity of the two melts is the primary variable determining the phase distribution in the mold. Generally the most uniform skin-core structure occurs when the second melt entering the mold has a slightly higher viscosity than the first melt injected. Large viscosity inequalities lead to nonuniform skin thicknesses. The influence of blowing agents and non-uniform temperature fields on the extent of encapsulation is described. Temperature fields are very important especially if the first polymer melt injected has a greater activation energy of viscous flow (or a greater temperature dependence of the viscosity function).     

Compositional differences among crambe samples and between seed components

Data germane to the processing and utilization of crambe as a new oilseed include information on variations to be expected in gross composition of the seed (fruit) and its component parts. Seventy-five samples ofCrambe abyssinica Hochst. ex R. E. Fries from experimental plantings in 17 states have been analyzed. Samples as received contained 16 to 62% pod material (pericarp), the extremes representing samples with many seeds removed from the pod or with many pods containing no seed. The amount of pericarp was most often between 25 and 40%. Oil content of seed (without pericarp) ranged from 36 to 54%, with most samples between 40 and 48%; crude protein from 22 to 37%, usually 25 to 30%; and erucic acid in the oil from 39 to 60%, usually 53 to 59%. Total thioglucoside content in 30 samples ranged from 8 to 10% calculated asepi-progoitrin in oil-free meal, although 2 samples were between 4 and 5%. One sample was hand-separated into pericarp (40%) and seed, and the latter was further separated into seed coat (8%), cotyledon (82%) and hypocotyl (10%). The pericarp contained only 0.4% lipid and the respective seed fractions 17, 55 and 38%. Their corresponding protein contents were 4, 23, 23 and 34%; and their thioglucoside contents (oil-free meal), 0.1, 2.1, 10.9 and 13.0%. Cotyledon and hypocotyl were quite similar in amino acid composition. Neither contained hydroxylproline, which is in both pericarp and seed coat. Presented at AOCS meeting in Chicago, October 1964. No. Utiliz. Res. Dev. Div. ARS, USDA. Crops Research Division, ARS, USDA.     

Electrochemical behaviour of titanium(II) and titanium(III) compounds in molten lithium chloride/ potassium chloride eutectic melts

The nature of the open circuit potentials of Ti and TiC electrodes in titanium(II) and titanium(III) chloride solutions, the apparent valency of the titanium ions in the melt immediately after the anodic dissolution of TiC and Ti, as well as the anodic dissolution of Ti, have been investigated in order to explain the oxidation-reduction process of titanium in lithium chloride-potassium chloride eutectic melts. It is shown that the standard electrode potential for TiC/Ti(III) exceeds that for the oxidation of Ti(II) to Ti(III). The anodic dissolution of TiC anodes give stable Ti(III) species at the standard electrode potentials the contrary to the behaviour of Ti metal anodes where the stable species are Ti(II) ions. Titanium electrodes in TiCl₃ solutions of molten lithium chloride-potassium chloride melts behave according to the Ti(III)/Ti(II) redox electrode potential of the reaction: Ti+TiCl₃3TiCl₂. An anodic dissolution mechanism compatible with all the experimental facts is proposed.     

Simulation of linear viscoelastic flow behavior in the Buss Kneader

Viscoelastic flow in a Buss Kneader in which the screw has both rotating and oscillating motions is simulated. Linear viscoelastic responses are considered using both the Maxwell model and the Boltzmann superposition model. Calculations are made first in a basic screw element and subsequently in Kneader screw modules where we consider leakage flows through the interrupted screw flights. Our study includes filled length variation in the crosshead screw extruder, screw characteristics of Kneader screw elements, and pressure profiles along the modular Kneader machine.     

Rust-red grain beetle,Cryptolestes ferrugineus,and flat grain beetle,Cryptolestes pusillus: Antennal and behavioral responses to synthetic components of their aggregation pheromones

Antennal and behavioral responses of the rust-red grain beetle,Cryptolestes ferrugineus, and the flat grain beetle,C. pusillus, to synthetic samples of the macrocyclic lactones reported to comprise their aggregation pheromones were investigated. Electroantennogram (EAG) recordings were obtained successfully from both species for the first time. Females of both species showed larger EAGs than males. The EAGs ofC. ferrugineus showed a high degree of specificity for conspecific aggregation pheromone components;C. pusillus showed much less specificity. Behavioral tests were conducted using two-choice pitfall bioassays. Separation of the results into the two effects of activity stimulation and direction finding showed that both effects contributed to the overall response, although sometimes to different extents. The strain ofC. pusillus studied responded equally well to both components of its pheromone, whereas it had been reported previously that only one was active, the other acting as a Synergist and eliciting no response when tested alone. With both species, behavioral response was elicited with a single lactone, suggesting that it might not be necessary to use both components for field use. Particularly surprising was thatC. pusillus showed a greater response to the pheromone components ofC. ferrugineus than to its own. Aeration of the two species and thermal desorption of the collected volatiles confirmed production of the expected lactones, and aeration of authentic lactones showed that the response was not due to the C.ferrugineus pheromone components being markedly more volatile. This response, which seems to be an actual preference, is the first to be discovered among the cucujid beetles and encourages optimism that a practical lure for various species may not need to be as complex as originally feared.     

Photocatalytic study of polymorphic titania synthesized by ambient condition sol process

Nanocrystalline titania of different phases were produced by ambient condition sol process with phase control originating from alterations in experimental variables. The produced titania photocatalysts were characterized by use of x-ray diffraction, BET surface area, transmission electron microscopy and related to methyl orange degradation. The results showed that the photocatalytic activity of brookite and anatase phase titania samples to be greater than that of Degussa P-25 and rutile phase titania sample. In addition, brookite, due to surface area considerations, appears to be the most photocatalytically active phase of titania.