Lymphocyte and macrophage responses after vaccinia virus infections

Using a semimicromethod with washed whole blood, in vitro lymphocyte responses of rabbits to intradermal infection with vaccinia virus was studied. Peritoneal exudate macrophages were infected with vaccinia in vitro to determine the time of appearance of activated macrophages. After primary infection, an increase in spontaneous incorporation of thymidine by blood cultures was found as early as 2 days postinfection. This effect was at a maximum at 7 to 10 days, with counts up to 100-fold higher than before infection. Incubation of these cultures with concanavalin A showed a marked decrease in stimulation index as compared with normals. Although only a transient stimulation with vaccinia was found during the acute infection, stimulation indexes of 2 to 3 were obtained during convalescence. Macrophages from rabbits early after infection supported vaccinia replication, whereas those at day 6 or later resisted infection. Macrophage resistance persisted for 2 to 3 weeks. The response of lymphocytes from rabbits reinfected with vaccinia after 15 weeks differed, with a small increase in spontaneous thymidine uptake, a smaller depression in concanavalin A stimulation, and a greater specific response to vaccinia. Macrophage activation occurred earlier and persisted for a longer time after secondary infection.     

Occupational lead poisoning, animal deaths, and environmental contamination at a scrap smelter

Occupational lead poisoning and environmental contamination were evaluated at a lead scrap smelter. Thirty of 37 employees (81 per cent) has blood lead levels of greater than or equal to 80 mug/100 ml, indicating unacceptable absorption, and 35 had free erythrocyte protoporphyrin (FEP) levels greater than 60mug/100ml rbc, indicating toxicity of lead on heme metabolism in red blood cells; eight current and previous employees had been hospitalized with lead colic, and another with encephalopathy. Levels of lead in surface soil (1,800 ppm) and vegetation (20,000 ppm) at the smelter were high and decreased with distance. Animals on nearby pasture had died, and lead levels in the blood, milk, and hair of large and small animals were elevated. Adults living within 100 meters of the smelter had higher blood and hair lead levels than controls, who lived at greater distances, but there was no evidence in them of lead toxicity.     

Abnormality in metabolism of 15N-labeled nitrate in toxemia

The urinary excretion of 15N-labeled ammonium nitrate was studied during the last few weeks in patients with normal pregnancy and in those with toxemia. Marked diminution of the 15N label was found consistently in patients with toxemia in the urinary fraction consisting of nitrogenous compounds other than urea and ammonia. The possible significance of this finding is discussed.     

The direct observation and analysis of dislocations in experimentally deformed plagioclase feldspars

Transmission electron microscopy has been used to observe and analyse the dislocations in a series of plagioclase feldspars which had been experimentally deformed in compression. The results indicate that a moving dislocation in these materials leaves behind a fault in the structure. Two types of fault are observed but both define the slip plane of the associated dislocation. From these observations, together with stuctural considerations, the visibility of the dislocations and the orientatation of the applied shear stress it has been possible to determine the slip system uniquely for a number of dislocations. The origin of the dislocations and the nature of the faults are also discussed.     

Creating cognitive tutors for collaborative learning: steps toward realization

Our long-term research goal is to provide cognitive tutoring of collaboration within a collaborative software environment. This is a challenging goal, as intelligent tutors have traditionally focused on cognitive skills, rather than on the skills necessary to collaborate successfully. In this paper, we describe progress we have made toward this goal. Our first step was to devise a process known as bootstrapping novice data (BND), in which student problem-solving actions are collected and used to begin the development of a tutor. Next, we implemented BND by integrating a collaborative software tool, Cool Modes, with software designed to develop cognitive tutors (i.e., the cognitive tutor authoring tools). Our initial implementation of BND provides a means to directly capture data as a foundation for a collaboration tutor but does not yet fully support tutoring. Our next step was to perform two exploratory studies in which dyads of students used our integrated BND software to collaborate in solving modeling tasks. The data collected from these studies led us to identify five dimensions of collaborative and problem-solving behavior that point to the need for abstraction of student actions to better recognize, analyze, and provide feedback on collaboration. We also interviewed a domain expert who provided evidence for the advantage of bootstrapping over manual creation of a collaboration tutor. We discuss plans to use these analyses to inform and extend our tools so that we can eventually reach our goal of tutoring collaboration.     

Generation of accurate on-chip time constants and stabletransconductances

A method for generating accurately known on-chip time constants and less accurate but stable transistor transconductances over process, power-supply, and temperature variations is presented. The technique uses a constant-g_m bias circuit, which has a resistor that is tuned with a fully integrated CMOS phase-locked loop (PLL) locked to an external frequency reference (normally present in most systems). Other on-chip analog circuits biased using the same constant-g_m bias circuit are also stabilized. The PLL uses a charge-pump structure with three control loops (two digital and one analog) having overlapping ranges with hysteresis to minimize tuning glitches in the steady state. The PLL has a lock range of 135 to 300 MHz, and displays an RMS jitter of 15.6 ps. The transconductances generated from the circuit display a 2.2% variation for a 60°C change in temperature, and a 1.3% variation for a 10% variation in power-supply voltage. The design has been fabricated in a 0.35-μm CMOS process, using an active area of 1200×1200 μm² and draws 5.8 mA from a 3.3-V supply     

Simultaneous backward conditioned inhibition and mediated conditioning.

Demonstrations of retrospective revaluation suggest that remembered stimuli undergo a reduction in association with the unconditioned stimulus (US) present during learning. Conversely, demonstrations of mediated conditioning in flavor-conditioning experiments with rats suggest that remembered stimuli undergo an increase in association with the US present during learning. In a food allergy prediction task with 23 undergraduates, we demonstrated simultaneous backward conditioned inhibition and mediated conditioning effects. These results are compatible with the hypothesis that the direction of change (decrease or increase) in associative strength depends on whether the remembered stimulus was of a different category (conditioned stimulus/antecedent) or the same category (US/outcome) as the presented US. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Experimental investigation of axial dispersion in a horizontal rotating cylinder

This work reports experimental measurements of the dispersion of particles during rotation in a horizontal cylinder. The axial dispersion of a pulse of approximately monodisperse black glass ballotini into a bed of clear glass ballotini of the same size is analysed. This is done using a sectioning technique, where the concentration is determined throughout the cylinder for a given rotation time and speed. The concentration profile is fitted to an appropriate solution of Fick’s second law to determine the dispersion coefficient. The dispersion coefficient is compared for various drum rotation rates and glass ballotini sizes. The cylinder was filled to 35 % by volume and rotated at a range of speeds between 5 and 20 rpm. The particle sizes vary from 1.14 to 3.15 mm. The dispersion coefficient was found to be dependent on both particle size and rotation speed. As the rotation speed, \(\omega \), was increased the dispersion coefficient increased proportionally to \(\omega ^{0.8}\). As the particle diameter, \(d_p\), was increased the dispersion coefficient increased proportionally to \(d_p^{1.84}\). These results are compared with previous experimental and simulation data, in particular the simulations of Third et al. (Powder Technol 203:510, 2010). Strong agreement was found between the simulations of Third et al. and the experimental results.

     

Bragg-wave scattering and the narrow-vee wake

A coherent radar on a cliff overlooking the ocean was used to illuminate the ocean surface at a grazing angle of 10° during and after the passage of a ship through the beam. Simultaneous L-band and X-band data were collected. The display of surface reflectivity (power) showed a prominent narrow-vee feature at L-band, as was observed in earlier L-band satellite observations. A corresponding narrow-vee structure was observed in X-band, but was not as strong as other components of the wake signature. On the other hand, the Doppler-velocity displays at both radar frequencies yielded the same distinctive signature, i.e., a pair of compact features traveling outward from the centerline, each exhibiting a Doppler velocity that was the Bragg phase velocity corresponding to that radar frequency. The location of the velocity signature coincided at L-band with that of the power signature. Further, the L-band wake was persistent enough to verify that the feature was propagating at the Bragg group velocity, roughly the same as that for X-band. This result confirms an earlier hypothesis that the mechanism underlying the narrow-vee signature is the outward propagation of Bragg waves created by the ship's passage     

A comparison of transthoracic impedance using standard defibrillation paddles and self-adhesive defibrillation pads

Because of the typical metaphyseal-epiphyseal growth of giant cell tumors and chondroblastomas, the optimal result of an en bloc resection can usually only be achieved by a loss of joint function. For this reason, intralesional excision has prevailed, though it leads to a high rate of relapses. Adjuvant therapy involving irrigation of the remaining bone cavity with phenol can distinctly decrease the rate of relapse. Little is known about the amount of phenol applied that is absorbed. This study investigated the urinary excretion of phenol following the instillation of 102 ml of a 5% phenol solution. The method consisted of urine collection from 11 patients treated by phenol instillation preoperatively, and at 1, 3, 6, 12 and 24 h postoperatively. The urine specimens were analysed for phenol by mass spectrometry. Preoperatively, the value was 5.1 mg/l on average. The maximum concentration of 62 mg/l was found 1 h after instillation, with an average value of 41.5 mg/l, and after 3 h of 18.9 mg/l. A further rapid decrease in the excretion rate was recorded, with normal values being reached after 12 h. This means a maximum of 9% and an average of 2% of the instilled amount of phenol were excreted in the urine within 24 h postoperatively. By comparing these urinary concentrations to published standards, we conclude that the instillation of a 5% phenol solution into bony lesions is associated with a relatively low risk of systemic toxicity.