The Rat Genome Database (RGD) facilitates genomic and phenotypic data integration across multiple species for biomedical research.

Model organism research is essential for discovering the mechanisms of human diseases by defining biologically meaningful gene to disease relationships. The Rat Genome Database (RGD, ( https://rgd.mcw.edu )) is a cross-species knowledgebase and the premier online resource for rat genetic and physiologic data. This rich resource is enhanced by the inclusion and integration of comparative data for human and mouse, as well as other human disease models including chinchilla, dog, bonobo, pig, 13-lined ground squirrel, green monkey, and naked mole-rat. Functional information has been added to records via the assignment of annotations based on sequence similarity to human, rat, and mouse genes. RGD has also imported well-supported cross-species data from external resources. To enable use of these data, RGD has developed a robust infrastructure of standardized ontologies, data formats, and disease- and species-centric portals, complemented with a suite of innovative tools for discovery and analysis. Using examples of single-gene and polygenic human diseases, we illustrate how data from multiple species can help to identify or confirm a gene as involved in a disease and to identify model organisms that can be studied to understand the pathophysiology of a gene or pathway. The ultimate aim of this report is to demonstrate the utility of RGD not only as the core resource for the rat research community but also as a source of bioinformatic tools to support a wider audience, empowering the search for appropriate models for human afflictions.

[Surgical management of thyroid diseases]. / Operative Therapie von Erkrankungen der Schilddrüse.

Operations of the thyroid gland belong to the most frequent surgical procedures in Germany. Ultrasound is used for examination of the morphology and scintigraphy for examination of the function of the thyroid gland. Cytology can be used to examine scintigraphically cold nodules. Nodules represent the most frequent indication for thyroid surgery. In differentiated thyroid carcinoma postoperative radioactive iodine therapy plays an important role. Operations of the thyroid gland should be performed with optical magnification to identify the recurrent laryngeal nerve with the help of neuromonitoring. A missing electric signal after stimulation of the nerve with intact morphology is indicative of temporary paresis of the vocal cord and operation of the contralateral side should be postponed. Thus, a bilateral paresis can be safely avoided.

Effects of amorphous layers on ADF-STEM imaging.

A study of high-resolution ADF imaging in uncorrected and aberration-corrected STEMs was carried out by multislice simulation. The presence of amorphous layers at the surface of a crystalline specimen is shown to significantly alter the visibility of the atomic columns. After propagating through an amorphous layer a portion of the beam passes without any alteration while scattered electrons introduce a Gaussian background. The dependence of the image contrast on the crystal structure, orientation and the types of the atoms present in the crystal was studied. In the case of uncorrected probes an amorphous layer thicker than 200 A is necessary to achieve considerable reduction of the visibility of the atomic columns, but with aberration-corrected probes only 60 A is necessary. With changes in defocus, crystalline specimens with amorphous layers on the top can also be imaged and high-resolution ADF images can be obtained. An amorphous layer at the beam entry surface affects the ADF image more than that of an amorphous layer at the exit surface. Approximately linear reduction of the contrast (with a slop of 1) is expected with increased thickness of amorphous layer.

Critical role of inelastic interactions in quantitative electron microscopy.

A semiquantitative correlation between experimental observations and theoretical prediction in electron microscopy is achieved. Experiments conducted on amorphous silicon in the convergent beam electron diffraction mode provide measurements of the reduction of the central-disk intensity. In addition to elastic scattering the effects of multiple inelastic scattering of the probe electrons were incorporated into the theory describing beam propagation through the specimen. With incorporation of the dominant plasmon scattering a better than 10% match of the theory with experiment is observed indicating the critical role of multiple inelastic scattering in quantitative electron diffraction and imaging.

Effects of tilt on high-resolution ADF-STEM imaging.

A study of the effects of small-angle specimen tilt on high-resolution annular dark field images was carried out for scanning transmission electron microscopes with uncorrected and aberration-corrected probes using multislice simulations. The results indicate that even in the cases of specimen tilts of the order of 1 degree a factor of 2 reduction in the contrast of the high-resolution image should be expected. The effect holds for different orientations of the crystal. Calculations also indicate that as the tilted specimen gets thicker the contrast reduction increases. Images simulated with a low-angle annular dark field detector show that tilt effects are more pronounced in this case and suggest that these low-angle detectors can be used to correct specimen tilt during scanning transmission electron microscopes operation.