The central problem in scaling up oligonucleotide synthesis is to expose each element of a large bed to the same conditions obtaining in very small ones, for the same intervals of time. Our analysis suggests that scale-up is chiefly limited by fluid path length through the bed. By using annular beds in zonal centrifuge rotors of unique design, with fluid flow controlled by combining centrifugal force with differences in physical density between reagents, reagent fronts may be kept exactly perpendicular to the direction of flow in each bed element. Under these conditions, bed volume may be increased by increasing rotor length and diameter. The rotor is lined with polypropylene or Teflon, and has a thick tempered glass end window. Transparent rotary valves of a unique design allow any of 47 reagents to be selected and the direction of flow through the rotor to be controlled. A photodiode spectrophotometer provides complete absorption spectra on fluid in the rotor inlet and outlet lines every 4 s, and a large balance weighs effluent from the synthesizer continuously. The entire operation is controlled by a work station, and steps may be programmed by time, absorbance, or reagent mass. Reagents are identified by spectra, and trityls are integrated on line. A detailed time-stamped log file provides a complete record of each synthesis.

Equipment Design↗

PubMedDate not supplied

Taming effects of handling on 6-hydroxydopamine induced ratge.

The purpose of this experiment was to determine the importance of handling to the expression of hyperemotional behaviors, i.e., rage, known to occur after chronic depletion of brain norepinephrine (NE) and dopamine (DA) following central injection of 6-hydroxydopamine (6-OHDA) in rats. Five min of handling per day for 6 consecutive days reduced resistane to capture as well as the magnitude and frequency of startle responding following one 300 mug injection of 6-OHDA intracisternally. Both 6-OHDA-handled and 6-OHDA-unhandled rats showed comparable levels of brain NE, DA, serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), comparable resting levels of plasma corticosterone, and comparable adrenal weights. These data demonstrate the importance of handling to the expression of 6-OHDA-induced rage and emphasize the importance of controlling for handling as a variable which can significantly affect the assessment of rage by behavioral criteria in this animal model of hyperemotionality.

Anger↗

PubMedDate not supplied

Effect of hemodialysis on red cell organic and inorganic phosphates.

Red cell 2,3 diphosphoglyceric acid (DPG), total nucleotide phosphate, inorganic phosphate, and plasma inorganic phosphate were measured at the onset and termination of 22 hemodialyses performed for chronic renal failure in 19 patients. Plasma inorganic phosphate decreased from a mean of 2.05 mM/liter +/- 0.14 to 1.26 mM/liter +/- 0.09 (p less than 0.005) while intracellular inorganic phosphate fell from 1.76 mM/liter +/- 0.12 RBC water to 1.21+/-mM/liter (p less than 0.005). Mean DPG was 6.37 mM/liter RBC +/- 0.23 at the start of the dialysis and 6.08 mM/liter +/- 0.24 at the termination (p=n.s.). Mean nucleotide concentration was 5.90 mM phosphorous content/liter RBC+/-0.26 at the start and 5.95 mM/liter 0.21 at the end (p=n.s.). Although there were significant decreases in intracellular and plasma inorganic phosphate concentrations immediately following dialysis, neither the DPG nor nucleotide phosphate concentrations were significantly altered by this short-term procedure. Red cell water inorganic phosphorous rapidly attained identical concentration with plasma water inorganic phosphorous.

Adenosine Diphosphate↗

PubMedDate not supplied

CAI: a strategy for retaining minority and academically disadvantaged students.

A computer assisted instruction (CAI) program was implemented as a teaching-learning strategy to retain students with academic deficiencies and increase their chances of being successful. The CAI programs were based on curriculum, course, and specific unit objectives. The CAI programs helped reduce the number of student failures in a medical-surgical nursing course which previously had a high attrition rate. The authors discuss the potential CAI has for assisting minority and disadvantaged students in successfully completing the baccalaureate nursing program.

Computer-Assisted Instruction↗

PubMedDate not supplied

Measuring variability in early child language: don't shoot the messenger.

Feldman et al. criticize the MacArthur Communicative Development Inventories (CDIs) as having too much variability, too little stability, and insufficient ability to predict early language delay. We present data showing that these characteristics of the CDI are authentic reflections of individual differences in early language development rather than measurement deficiencies. We also respond to their critical assertions concerning sociodemographic influences on the CDI scores.

Child Development↗

PubMedDate not supplied

Computer-based learning: games as an instructional strategy.

Games are a creative teaching strategy that enhances learning and problem solving. Gaming strategies are being used by the authors to make learning interesting, stimulating and fun. This article focuses on the development and implementation of computer games as an instructional strategy. Positive outcomes have resulted from the use of games in the classroom.

Computer-Assisted Instruction↗

PubMedDate not supplied

Specialist in patient transfer.

Explore the source record for details and available documents.

Critical Care↗

PubMedDate not supplied

[Communication interventions: windows of opportunity].

OBJECTIVE: An understanding of how verbal and non verbal language develops and how it is related to social behavior is essential in order to devise effective interventions for children with disorders of communication. We review the literature on interventions for children with communication disorders from the perspective of the clinical neurologist emphasizing both therapeutic and pharmacological interventions. FINDINGS: Our knowledge on effective interventions in children with disorders of communications is limited due to the heterogeneity of the population and the lack of well controlled studies. There is some limited data suggesting that therapeutic interventions for children with language impairments are most effective if all forms of communication are emphasized. Interventions should be adapted to the age of presentation and associated clinical findings of the child. CONCLUSIONS: A multimodal intervention approach is essential to maximize the potential of children with communication disorders. The role of medication in interventions for children with disorders of communication is limited to the treatment of associated symptoms that may interfere with the ability of a child to receive non pharmacological therapeutic interventions.

Brain↗

PubMedDate not supplied

Radioactive materials in biosolids: national survey, dose modeling, and publicly owned treatment works (POTW) guidance.

The Nuclear Regulatory Commission (NRC) announced the availability of three new documents concerning radioactive materials in sewage sludge and ash from publicly owned treatment works (POTW). One of the documents is a report presenting the results of a volunteer survey of sewage sludge and ash samples provided by 313 POTWs. The second document is a dose modeling document, using multiple exposure pathway modeling focused on a series of generic scenarios, to track possible exposure of POTW workers and members of the general public to radioactivity from the sewage sludge or ash. The third document is a guidance report providing recommendations on the management of radioactivity in sewage sludge and ash for POTW owners and operators. This paper explains how radioactive materials enter POTWs, provides criteria for evaluating levels of radioactive material in sludge and ash, and gives a summary of the results of the survey and dose modeling efforts.

Data Collection↗