Precalculated artificial lens implantation with refractive balance

The two main possibilities of error of the generally used methods for artificial lens implantation after preoperative ultrasound measurements and calculations are discussed. By using our additional special calibration to the ultrasonic equipment we can predict the postoperative refraction with an error of +/- 0.5 D corresponding to an uncorrected vision of about 20/40 and better. Procedures based on the validity of Knapp's law may lead to optical pitfalls, since Knapp's law is only valid for eyes with variable eye length, while it is known that human phakic, pseudophakic and aphakic eyes have a constant eye length. Three principles for the precalculated artificial lens implantation are published and results of refractive balances are given.     

Interaction of non-histone chromosomal proteins HMG1 and HMG2 with DNA

Interaction between non-histone protein HMG1 or HMG2 and DNA has been studied by using thermal denaturation and circular dichroism (CD) spectroscopy. We have made the following observations. 1. The binding of each of these two proteins to DNA stabilizes the latter, as shown by an increase in melting temperature of 20 degrees C (from 45 degrees C to about 65 degrees C). 2. There are 6.0 amino acids/nucleotide in HMG1-bound DNA and 5.0 in HMGI-bound DNA which suggests that each HMB1 moleculae would cover about 20 base pairs of DNA and each HMG2 molecule would cover about 25 base pairs. 3. The alpha-helical content of these two non-histone proteins in the complexes, estimated from the CD value at 220 nm, is about one third to one half that of total proteins in calf thymus chromatin. 4. DNA conformation is distorted only slightly by the binding of protein HMG1 or HMG2. 5. Neither the melting nor the CD properties of HMG1-DNA or HMG2-DNA complexes differ substantially whether they are prepared by NaCl-gradient dialysis in urea or by direct mixing of protein and DNA at 0.15 M NaCl, followed by dialysis against the same buffer i.e. 0.25 mM EDTA (pH 8.0).     

Assessment of regional myocardial uptake and metabolism of omega-(p-123I-phenyl) pentadecanoic acid with serial single-photon emission tomography

The utility of myocardial imaging and assessment of regional myocardial metabolism of omega-(123I-paraphenyl-)pentadecanoic acid (I-PPA) by means of serial single-photon tomography is demonstrated in animal experiments. High quality cross sectional images of dog hearts with clear delineation of left ventricular walls are obtained. Myocardial infarcts are visualized as areas of deficient radioactivity uptake. I-PPA elimination from non-infarcted myocardial regions is significantly (p less than 0.001) prolonged when compared with unaffected controls. Hence, not only localized absence of uptake of free fatty acid by infarcted myocardium can be demonstrated with serial single-photon tomography but also general impairment of cardiac FFA-metabolism.     

Cognitive and learning difficulties and how they affect access to IT systems

In October 2005, the IBM Human Ability and Accessibility Center and T.J. Watson Research Center hosted a symposium on “cognitive and learning difficulties and how they affect access to IT systems”. The central premise of the symposium was the recognition that cognitive and learning difficulties have a profound impact on a person’s ability to interact with information technology (IT) systems, but that little support is currently being offered by those systems. By bringing together internationally renowned experts from a variety of different, but complementary, research fields, the symposium aimed to provide a complete overview of the issues related to this topic. This paper summarises the discussions and findings of the symposium.     

Teaching high school students to use heuristics while reading historical texts.

The purpose of this study was to test the effectiveness of different types of instruction and texts on high schools students' learning of (a) history content and (b) a set of heuristics that historians use to think critically about texts. Participants for the study were 128 male and 118 female students, ages 16 and 17 years, from 2 high schools in the western United States. Eight history classrooms were randomly assigned to 1 of 4 interventions: (a) traditional textbooks and content instruction, (b) traditional textbooks and heuristic instruction, (c) multiple texts and content instruction, or (d) multiple texts and heuristic instruction. The heuristic instruction explicitly taught sourcing, corroboration, and contextualization. Students were administered pretests on their content knowledge and their use of heuristics. After an intervention of 3 weeks, students were readministered the content knowledge and heuristics posttests. A mixed-model analysis of covariance indicated that across all conditions, students who read multiple texts scored higher on history content and used sourcing and corroboration more often than students who read traditional textbook material. Findings highlight the importance of reading multiple texts to deepen content knowledge and facilitate the use of heuristics that historians typically use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)