The Tradeoff Between Delay and TASI Advantage in a Packetized Speech Multiplexer

A packetized speech multiplexer differs from a circuitswitched TASI system in that the presence of a packet buffer allows a tradeoff where the TASI advantage can be increased at a cost in packet delay. This tradeoff is investigated via a simulation. Results are presented to show the relations between TASI advantage and delay, for both an average delay criterion and a maximum delay criterion. It is shown that, particularly for the case where small numbers of talkers are multiplexed, the packetized system offers significant improvements in TASI advantage over the conventional circuit-switched multiplexer, at modest costs in packet delay.     

Experimental induction of maligant tumors in the urinary bladder of the rabbit

Suspended material of Brown-Pearce carcinoma is qualified for producing bladder tumors in rabbits after injection into the wall of the exposed, but not opened bladder. The advantages are the rapid growing and the possibility of controlling by endoscopy and radiography. At present we use this tumor-pattern for examination of the effect of different laser beams in experimental bladder tumors.     

A-scsan sonography for the measurement of the thickness of the bladder wall

The A-mode ultrasonography is especially qualified for measuring tissue thickness. By using high frequencies (8--10 MHz) upper layers can be measured with an accuracy of approximately 0.15 mm. This accuracy in measurement is required in connexion with optimization of dose during therapy of urinary bladder tumors by way of the Neodymium-YAG laser. The newly developed 8 MHz-endo-transducer makes possible intravesical measurement of bladder-wall thickness under cystoscopoic view. This method presents itself as a new opportunity for staging urinary bladder tumors.     

Mycoplasma prostatourethritis. The improtance of immunoelectrophoresis of the ejaculate for the diagnosis

The secretions expessed from the prostate and/or urethral smears from 846 patients of a prostatitis clinic were examined microbiologically. With negative findings in 62.9%, which suggested a high proportion of patients with a vegetative urogenital syndrome, mycoplasma could be isolated in 9.9% of the entire collective. In the cases with mycoplasma in the expressed prostatic secretion, a close, statistically significant correlation to the degree of clinical complaint and the mumber of leukocytes in the secretion was established. Immunoelectrophoresis of the ejaculate was carried out in 20 subjects in the mycoplasma group. Although unequivocal statement are not yet possible because of the small number of cases, there is a statistically striking trend towards infection with urea-splitting mycoplasma when the immunoelectrophoresis of the ejaculate is unchanged, which might indicate the induction of a predominantly localised urethritis due to this strain.     

Triple Culture of Primary Human Osteoblasts,Osteoclasts and Osteocytes as an In Vitro Bone Model

In vitro evaluation of bone graft materials is generally performed by analyzing the interaction with osteoblasts or osteoblast precursors. In vitro bone models comprising different cell species can give specific first information on the performance of those materials. In the present study, a 3D co-culture model was established comprising primary human osteoblasts, osteoclasts and osteocytes. Osteocytes were differentiated from osteoblasts embedded in collagen gels and were cultivated with osteoblast and osteoclasts seeded in patterns on a porous membrane. This experimental setup allowed paracrine signaling as well as separation of the different cell types for final analysis. After 7 days of co-culture, the three cell species showed their typical morphology and gene expression of typical markers like ALPL, BSPII, BLGAP, E11, PHEX, MEPE, RANKL, ACP5, CAII and CTSK. Furthermore, relevant enzyme activities for osteoblasts (ALP) and osteoclasts (TRAP, CTSK, CAII) were detected. Osteoclasts in triple culture showed downregulated TRAP (ACP5) and CAII expression and decreased TRAP activity. ALP and BSPII expression of osteoblasts in triple culture were upregulated. The expression of the osteocyte marker E11 (PDPN) was unchanged; however, osteocalcin (BGLAP) expression was considerably downregulated both in osteoblasts and osteocytes in triple cultures compared to the respective single cultures.