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Biomedical subjects

H Richter

Publications and source records attributed to H Richter.

340 records · Page 19Linked to original sources
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Solid phase synthesis of allylic alcohols via the Baylis-Hillman reaction.

An efficient method for the solid phase synthesis of allylic alcohols via the Baylis-Hillman reaction has been developed. In the presence of DABCO or 3-quinuclidinol the coupling of resin bound acrylic acid with different aldehydes yields allylic alcohols. Aldehydes with different reactivity were used and gave modest to excellent yields upon simply varying the base or the reaction time. The allylic alcohols were reacted with primary amines to form 1,3-aminoalcohols.

Aldehydes↗
PubMedDate not supplied

[The use of a methanol bacterial mass in multigenerational studies in the hen. 2. Laying period].

In a multi-generation trial with 120 or 96 hens of the breed White Leghorn per group the effect of diets containing 7.5% or 15.0% of methanol-grown dried bacterial cells was examined. The hens were kept in conventional three-stage battery. In two of the three experiments the feed intake was decreased if it was used methanol-grown bacterial cells as a protein source. The period of intensive laying (50% egg production) started later and the egg production has been decreased by using the bacterial cells. For the traits egg weight and mortality no relation to the nutrition could be found. The feeding of methanol-grown bacterial cells showed in two incubatory trials no negative effects on reproductive ability of the hens. The cock's sperm quality was not influenced in two experiments. In one trial the sperm volume was reduced and the sperm concentration was raised if diets contained methanol-grown dried bacterial cells. Indications of toxic influences of the methanol-grown bacterial cells were not found.

Animals↗
PubMedDate not supplied

Development of a completely encapsulated intraocular pressure sensor.

A completely encapsulated intraocular pressure (IOP) sensor equipped with telemetric signal and energy transfer is introduced integrated into a silicone disc for implantation into the eye. After implantation into enucleated pig eyes and into rabbit eyes in vivo, the IOP was recorded and compared to established techniques of IOP measurement. Pressure chamber tests showed that the sensor functioned correctly after biocompatible encapsulation in polydimethylsiloxane. In vivo and in vitro tests in rabbit and pig eyes demonstrated that the implanted system worked with the same precision as established techniques for IOP determination. The correlation between the measurements with the implanted device and pneumotonometry in several experiments was between 0.9 and 0.99. This device serves as a functioning model for the realization of a telemetric IOP sensor for integration into an artificial intraocular lens. Such a device will open new perspectives, not only in the management of glaucoma, but also in basic research for mechanisms of glaucoma.

Animals↗
PubMedDate not supplied

[Rotational bending test of hydroxylapatite plasma-coated models of TiAl6V4].

Plasma spraying of hydroxyapatite coatings onto hip joint and knee endoprosthesis implants and dental implants is state of the art. Nevertheless, there is still a lack of data on the long-term behavior of such coatings. Using the rotating-bending test DIN 50,113 it is shown that parts plasma-sprayed with 200 microns OSPROVIT exhibit delamination only after fracture of the metallic component. At a load of 400 MPa more than 1.10(9) loading cycles were achieved.

Alloys↗
PubMedDate not supplied

[Detection and prevalence of verotoxin-producing Escherichia coli (VTEC) in raw sausage].

We investigated 158 samples of shortly ripened raw sausages bought in supermarkets of Dessau within 4 month. In 14 (8.8%) samples Verotoxin-producing E. coli were detected. 13 VT-positive samples were found in the group of easily spread raw sausages. The 14 isolates belonged to 6 different O-serotypes. 4 VT1-, 8 VT2- and 2 VT1/VT2-producers were found. 4 isolates belonged to serogroups which were already described in WHO tables and associated with EHEC infections in human beings. One strain of serogroup O22: H8, isolated from a "Teewurst", possessed the complete virulence gene combination of EHEC (eae, hlyA, stx). The detection procedure, already successfully used for detection and isolation of VTEC from raw milk, soft cheese and raw minced beef showed a sensitivity of approximately 10 CfU/25 g of raw sausages. It has to be considered that VTEC are frequently (8.8%) present in shortly ripened raw sausages. The group of easily spread raw sausages has a higher VTEC-contamination rate than firm raw sausages. Raw sausages, especially easy to spread types, belong to the risk foods for EHEC-infections in human beings.

Animals↗