Further Studies on Selection for Resistance to Salmonella aertrycke in Mice

It was demonstrated by Schott in 1932 that selection for resistance in mice to a standard dose of 5 x 104 S. aertrycke bacteria was effective in decreasing the mortality from 82.3 per cent for the unselected foundation stock to 24.7 per cent in the sixth selected generation. Using the same material as the basis for further study, the complete results for the sixth generation gave a mortality of 22.5 per cent. Further decreases in mortality to 14.7 and 15.6 per cent were observed in the seventh and eighth generations respectively. Groups of mice belonging to the eighth generation when tested with a dose of 2 x 105 organisms gave a mortality of 25.4 per cent. With the 2 x 105 dose the mortalities decreased to 15.8 and 16.2 per cent in the tenth and eleventh generations respectively. Similar sets of mice belonging to the tenth and eleventh generations when tested with a dose of 2 x 106 bacteria gave mortalities of 32.4 and 23.3 per cent respectively. With a dose of 1 x 107 organisms the mortality rose to 40.3 per cent in the eleventh generation. A mortality of 47.2 per cent was observed in the twelfth generation with the dose 1 x 107

Inheritance of Resistance and Susceptibility to Salmonella aertrycke in Mice

In previous reports by the writer and others it has been shown that the resistance of a strain of mice to controlled infections of Salmonella acrtrycke could be greatly increased by selective breeding. After fourteen generations of selection for resistance to a standard close of 2 x 105 organisms the mortality in the selected stock (S) was only 8 per cent as compared with a mortality of approximately 98 per cent in the highly susceptible Silver (Sil) and Bagg albino (Ba) strains

Reengineered helmet coil for human brain studies at 3 tesla

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Stereoscopic depth increases intersubject correlations of brain networks

Three-dimensionalmovies presented via stereoscopic displays have becomemore popular in recent years aiming at a more engaging viewing experience. However, neurocognitive processes associated with the perception of stereoscopic depth in complex and dynamic visual stimuli remain understudied. Here, we investigate the influence of stereoscopic depth on both neurophysiology and subjective experience. Using multivariate statistical learning methods, we compare the brain activity of subjects when freely watching the same movies in 2D and in 3D. Subjective reports indicate that 3D movies are more strongly experienced than 2D movies. On the neural level, we observe significantly higher intersubject correlations of cortical networks when subjects are watching 3D movies relative to the same movies in 2D. We demonstrate that increases in intersubject correlations of brain networks can serve as neurophysiologicalmarker for stereoscopic depth and for the strength of the viewing experience

Safety and reliability of Radio Frequency Identification Devices in Magnetic Resonance Imaging and Computed Tomography

BACKGROUND: Radio Frequency Identification (RFID) devices are becoming more and more essential for patient safety in hospitals. The purpose of this study was to determine patient safety, data reliability and signal loss wearing on skin RFID devices during magnetic resonance imaging (MRI) and computed tomography (CT) scanning. METHODS: Sixty RFID tags of the type I-Code SLI, 13.56 MHz, ISO 18000-3.1 were tested: Thirty type 1, an RFID tag with a 76 x 45 mm aluminum-etched antenna and 30 type 2, a tag with a 31 x 14 mm copper-etched antenna. The signal loss, material movement and heat tests were performed in a 1.5 T and a 3 T MR system. For data integrity, the tags were tested additionally during CT scanning. Standardized function tests were performed with all transponders before and after all imaging studies. RESULTS: There was no memory loss or data alteration in the RFID tags after MRI and CT scanning. Concerning heating (a maximum of 3.6 degrees C) and device movement (below 1 N/kg) no relevant influence was found. Concerning signal loss (artifacts 2 - 4 mm), interpretability of MR images was impaired when superficial structures such as skin, subcutaneous tissues or tendons were assessed. CONCLUSIONS: Patients wearing RFID wristbands are safe in 1.5 T and 3 T MR scanners using normal operation mode for RF-field. The findings are specific to the RFID tags that underwent testing

Dominant Effect of Near-Interface Native Point Defects on ZnO Schottky Barriers

The authors used depth-resolved cathodoluminescence spectroscopy and current-voltage measurements to probe metal-ZnO diodes as a function of native defect concentration, oxygen plasma processing, and metallization. The results show that resident native defects in ZnO single crystals and native defects created by the metallization process dominate metal-ZnO Schottky barrier heights and ideality factors. Results for ZnO(0001) faces processed with room temperature remote oxygen plasmas to remove surface adsorbates and reduce subsurface native defects demonstrate the pivotal importance of crystal growth quality and metal-ZnO reactivity in forming near-interface states that control Schottky barrier properties

Age Mosaicism across Multiple Scales in Adult Tissues

Most neurons are not replaced during an animal’s lifetime. This nondividing state is characterized by extreme longevity and age-dependent decline of key regulatory proteins. To study the lifespans of cells and proteins in adult tissues, we combined isotope labeling of mice with a hybrid imaging method (MIMS-EM). Using ^(15)N mapping, we show that liver and pancreas are composed of cells with vastly different ages, many as old as the animal. Strikingly, we also found that a subset of fibroblasts and endothelial cells, both known for their replicative potential, are characterized by the absence of cell division during adulthood. In addition, we show that the primary cilia of beta cells and neurons contains different structural regions with vastly different lifespans. Based on these results, we propose that age mosaicism across multiple scales is a fundamental principle of adult tissue, cell, and protein complex organization