Investigation of the aluminum oxide content on structural and optical properties of germanium glasses doped with RE ions

In this paper structural and optical properties of Rare Earth doped (RE) gallo-germanate glasses modified with various amount of Al₂O₃ have been investigated. Glasses doped with Yb³⁺, Tm^3+, and Ho³⁺ ions were synthesized to study Al₂O₃ additive influence on their structural and emission properties in the visible spectral region. MIR spectra indicated that the structure of prepared glasses tends to order and its polymerization along with the aluminum content increase. Glass samples consisting of the low molar content of Al₂O₃ are characterized by a significant contribution of Tm³⁺ ions in light emission while Ho³⁺ ions luminescence dominates in samples consisting of the higher molar content of Al₂O₃. Additionally, investigation of light emission in visible range showed that samples consisting of the low molar content of Al₂O₃ are characterized by greenish blue light emission whereas light emitted by samples consisting of 15-20 mol% is much closer to the white colour.

[What is the value of the whole body spiral CT in the primary radiological imaging of severely injured children?]

AIM

Whole body spiral CT scans have become a routine method in the radiological imaging of severely injured patients in emergency rooms of an increasing number of hospitals. The routine use of CT scans is, however, still discussed controversially, especially with regard to its use in children. This is mainly due to the reportedly higher level of exposure to radiation of CT scans as compared to plain radiographs. The aim of the present study was to compare the dose of exposure to radiation of a whole body CT scan to that of a plain radiograph protocol in an animal model for severely injured children.

MATERIAL AND METHODS

We chose 3 female pigs of different weights to serve as a model for children at different ages. 4 film radiation dosimeters (positioned on the eye, under the breast, paravertebrally on the thoracic spine and in the small pelvis, respectively) were implanted into every pig for each examination. Plain radiographs of the chest and the pelvis in one plane and of the skull and the complete spine in two planes were performed. The CT scan included skull, cervical spine and the whole body from the thorax to pelvis.

RESULTS

The radiation dose of CT scans was 7 times higher as compared to the X-ray protocol, but the performance of CT scans was faster (8 vs. 18 min). The radiation dose of the whole body CT scan was at about 15 mSv.

CONCLUSION

Based on our data and a review of the literature we will use whole body spiral CT scans as the preferred method in the primary radiological imaging of severely injured patients. In our opinion, the evident benefit of a reduced time of imaging in combination with superior image information outweighs the higher level of exposure to radiation.

Disruption of insulin receptor substrate 2 causes type 2 diabetes because of liver insulin resistance and lack of compensatory beta-cell hyperplasia

To investigate the role of insulin receptor substrate (IRS)-2 in vivo, we generated IRS-2-deficient mice by gene targeting. Although homozygous IRS-2-deficient mice (IRS-2-/- mice) had a body weight similar to wild-type mice, they progressively developed type 2 diabetes at 10 weeks. IRS-2-/- mice showed insulin resistance and a defect in the insulin-stimulated signaling pathway in liver but not in skeletal muscle. Despite insulin resistance, the amount of beta-cells was reduced to 83% of that in wild-type mice, which was in marked contrast to the 85% increase in the amount of beta-cells in IRS-1-deficient mice (IRS-1-/- mice) to compensate for insulin resistance. Thus, IRS-2 plays a crucial role in the regulation of beta-cell mass. On the other hand, insulin secretion by the same number of cells in response to glucose measured ex vivo was significantly increased in IRS-2-/- mice compared with wild-type mice but was decreased in IRS-1-/- mice. These results suggest that IRS-1 and IRS-2 may play different roles in the regulation of beta-cell mass and the function of individual beta-cells.

Calcium requirements in humans. Report of original data and a review

Presently submitted and previously available data indicate that the recommended calcium requirement of 800 mg/day is inadequate for a large segment of the population, particularly the elderly. With an intake of 800 mg of calcium/day, calcium balance was only slightly positive, without consideration of dermal losses or other risk factors that may play a role in calcium bioavailability and calcium retention. A calcium intake of 1000-1200 mg/day is preferable, as calcium balance increased significantly when calcium intake was increased from 800 to 1200 mg/day; there was no further improvement in calcium balance on higher calcium intakes, up to 2300 mg/day.

Receptor binding studies on A1-(2-nitro-4-trimethylammoniophenyl)insulin

The results are presented from receptor binding studies and isolated fat cell assays on A1-(2-nitro-4-trimethylammoniophenyl)insulin. In the former tests, the derivative is shown to have properties similar to native insulin and the fat cell assays afford a value of 76 +/- 4%. The importance of a charged, hydrophilic moiety attached at A1-glycine is discussed in the light of the above findings.