Protein accumulation in cerebrospinal fluid during -90 degrees head-down tilt in rabbit

Plasma proteins are only somewhat larger than the intercellular spaces of the cerebral microvessels that constitute the blood-brain barrier or of the choroid plexus villi that elaborate cerebrospinal fluid (CSF). We hypothesized that the integrity of these barriers in anesthetized rabbits might be compromised during head-down tilt (HDT). Plasma protein and osmolality, hematocrit, and CSF protein concentration were compared in rabbits exposed to 1 h of HDT (n = 20) and prone rabbits (n = 10). In addition, the concentration of trypan blue dye, injected intravenously at the end of HDT or the prone position, was measured in brain homogenate. Finally, arterial blood pressure was measured via a catheterized carotid artery. HDT disrupted the barrier between blood and CSF, as indicated by a significantly (P < 0.01) greater brain trypan blue concentration in the HDT rabbits [172.2 +/- 14.4 (SD) micrograms/g dry wt] than in the prone rabbits (29.8 +/- 4.4 micrograms/g dry wt). Moreover CSF protein 5 min after HDT onset was significantly increased compared with control in HDT rabbits (54.6 +/- 1.9 vs. 81.4 +/- 5.2 mg/dl; n = 8) but not in prone rabbits (55.6 +/- 2.7 vs. 57.2 +/- 5.0 mg/dl; n = 6). Changes in the plasma protein-to-hematocrit ratio in the HDT animals, but not in the prone animals, were also compatible with a loss of fluid from the vascular compartment.(ABSTRACT TRUNCATED AT 250 WORDS)     

A group measure of the Piagetian concepts of conservation and egocentricity.

Presents a group test of Piagetian tasks. 30 male and 30 female 1st graders were tested using both group and individual procedures. A correlation was obtained across the 2 methods of assessment. Properties of the test were examined for internal and conceptual consistency. 2 scales employing a cartoon format were examined, each consisting of 6 items drawn from various clinical test situations described by Piaget. Scale I, conservation of substance, was shown to possess high internal consistency and a high degree of correspondence across the 2 methods of presentation. Scale II, egocentricity, was shown to possess poorer scale properties which are suggestive of a need for further refinement. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role conflict and ambiguity scales: Reality or artifacts?

Discusses 2 arguments against the role conflict and ambiguity scales developed by J. R. Rizzo et al (see record 1971-01407-001). The arguments focus on the positive and negative wording of the scale items and the self- and other-attributions found in the wording of the scale items. These arguments, if substantiated, would suggest modification of the Rizzo et al scales. The present study, with 272 adults, provided evidence that such arguments may not be able to be substantiated and that modification of the scales based on these arguments may not be necessary. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effectiveness of a laboratory-scale vertical tower static chamber steam pasteurization unit against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria innocua on prerigor beef tissue

A laboratory-scale vertical tower steam pasteurization unit was evaluated to determine the antimicrobial effectiveness of different exposure times (0, 3, 6, 12, and 15 s) and steam chamber temperatures (82.2, 87.8, 93.3, and 98.9 degrees C) against pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua) inoculated onto prerigor beef tissue. Samples were collected and microbiologically analyzed immediately before and after steam treatment to quantify the effectiveness of each time-temperature combination. The 0-s exposure at all chamber temperatures (cold water spray only, no steam treatment) was the experimental control and provided < or = 0.3 log CFU/cm2 reductions. Chamber temperatures of 82.2 and 87.8 degrees C were ineffective (P > 0.05) at all exposure times. At 93.3 degrees C, significant reductions (> 1.0 log CFU/cm2) were observed at exposure times of > or = 6 s, with 15 s providing approximately 1 log cycle greater reductions than 12 s of exposure. The 98.9 degrees C treatment was consistently the most effective, with exposure times of > or = 9 s resulting in >3.5 log CFU/cm2 reductions for all pathogens.     

Comparison of stress field forming methods for vibro-acoustography

Vibro-acoustography is a method that produces images of the acoustic response of a material to a localized harmonic motion generated by ultrasound radiation force. The low-frequency, oscillatory radiation force (e.g., 10 kHz) is produced by amplitude modulating a single ultrasound beam, or by interfering two beams of slightly different frequencies. Proper beam forming for the stress field of the probing ultrasound is very important because it determines the resolution of the imaging system. Three beam-forming geometries are studied: amplitude modulation, confocal, and x-focal. The amplitude of radiation force on a unit point target is calculated from the ultrasound energy density averaged over a short period of time. The profiles of radiation stress amplitude on the focal plane and on the beam axis are derived. The theory is validated by experiments using a small sphere as a point target. A laser vibrometer is used to measure the velocity of the sphere, which is proportional to the radiation stress exerted on the target as the transducer is scanned over the focal plane or along the beam axis. The measured velocity profiles match the theory. The theory and experimental technique may be useful in future transducer design for vibro-acoustography.     

Advances in encapsulation technologies for the management of mercury-contaminated hazardous wastes

Although industrial and commercial uses of mercury have been curtailed in recent times, there is a demonstrated need for the development of reliable hazardous waste management techniques because of historic operations that have led to significant contamination and ongoing hazardous waste generation. This study was performed to evaluate whether the U.S. EPA could propose treatment and disposal alternatives to the current land disposal restriction (LDR) treatment standards for mercury. The focus of this article is on the current state of encapsulation technologies that can be used to immobilize elemental mercury, mercury-contaminated debris, and other mercury-contaminated wastes, soils, sediments, or sludges. The range of encapsulation materials used in bench-scale, pilot-scale, and full-scale applications for mercury-contaminated wastes are summarized. Several studies have been completed regarding the application of sulfur polymer stabilization/solidification, chemically bonded phosphate ceramic encapsulation, and polyethylene encapsulation. Other materials reported in the literature as under development for encapsulation use include asphalt, polyester resins, synthetic elastomers, polysiloxane, sol-gels, Dolocrete, and carbon/cement mixtures. The primary objective of these encapsulation methods is to physically immobilize the wastes to prevent contact with leaching agents such as water. However, when used for mercury-contaminated wastes, several of these methods require a pretreatment or stabilization step to chemically fix mercury into a highly insoluble form prior to encapsulation. Performance data is summarized from the testing and evaluation of various encapsulated, mercury-contaminated wastes. Future technology development and research needs are also discussed.     

Rasch measurement using dichotomous scoring

The Rasch measurement model using dichotomous scoring of item response data from a newly created Mobility Scale administered to elderly independent living individuals is presented. The dichotomous scoring model, item calibration, person calibration, logit scale, normative scale score, reliability, and validity are explained. Results indicated that additional activity statements need to be written and tested to improve the Mobility Scale instrument.     

Apparatus and initial results for pressurized planar electrochromatography

Pressurized planar electrochromatography (PPEC) is a new planar chromatographic technique in which the mobile phase is driven by electroosmotic flow, while the sorbent layer is pressurized in a manner that allows heat to flow from the layer through an electrically insulating, thermally conducting, sheet of aluminum nitride ceramic. A prototype apparatus for performing PPEC is described. Separation by PPEC is faster than by conventional TLC, and an example is presented of a 24-fold enhancement in the speed of separation. PPEC was performed on both regular and high-performance C18 layers, and the latter yield substantially faster separation. The sorbent layer requires conditioning at elevated temperature before use, and solute migration velocity increases with this temperature. The flow rate increases in a linear manner with increasing voltage and diminishes in a nonlinear manner with increasing pressure. Both electrical current and Joule heating diminish with increasing pressure, and the diminution of flow at high pressure can be compensated by an increase in voltage. PPEC is more efficient than classical TLC. Theoretical plate heights diminish with increasing Rf and are in the range 29-21 and 55-27 microm for the high-performance and regular plates, respectively. PPEC retains the advantages of classical TLC but has the ability to separate a substantially higher number of samples simultaneously. An example is presented on the separation of nine samples in 1 min on a 2.5 cm x 10 cm sorbent layer.     

High-throughput comprehensive analysis of human plasma proteins: a step toward population proteomics

A high-throughput (HT) comprehensive analysis approach was developed for assaying proteins directly from human plasma. Proteins were selectively retrieved, by utilizing antibodies immobilized within affinity pipet tips, and eluted onto enzymatically active mass spectrometer targets for subsequent digestion and structural characterization. Several parameters, including uniform parallel protein elution from 96 affinity pipet tips, proper buffering for on-target digestion, termination of the digestion, and MALDI matrix (re)introduction, were evaluated and optimized. The approach was validated via parallel, high-throughput analysis of transthyretin (TTR) and transferrin (TRFE) from 96 identical plasma samples. The 96 parallel analyses for each protein were completed in less than 90 min, measured from protein extraction to insertion in the mass spectrometer. Virtually identical mass spectra were obtained from the 96 TTR analyses, characterized by the presence of 14 tryptic fragments that allowed TTR sequence mapping with 100% coverage. Database search returned TTR as the best match for all 96 data sets. In regard to the TRFE analyses, database searching using data from the 96 spectra returned TRFE as the best match for all but 1 of the spectra. TRFE was mapped with 47-69% sequence coverage, with gaps in the sequence coverage corresponding to the carbohydrate-containing peptide fragments and large and small trypsin fragments that fell outside the window of mass analysis. Overall, the combined high-throughput affinity capture-protein digestion approach showed high reproducibility and speed and yielded an exceptional level of protein characterization, suggesting its use in future population proteomics endeavors.     

Phosphorus removal in the activated sludge process

The results from this research suggest that both calcium phosphate precipitation and enhanced biological uptake play a role in phosphorus removal in the activated sludge process when a non-nitrifying, anaerobic-aerobic system is used to treat a low calcium wastewater. The primary removal mechanism was found to be biological uptake, as calcium phosphate precipitation accounted for only 15–27% of the total phosphorus removed. Calcium phosphate precipitation in the aerobic unit was enhanced because of the pH increase in that reactor. This was the result of low CO₂ production (indicated by low specific oxygen uptake values) and intense aeration which caused excessive CO₂ stripping in the aerobic unit