Biomedical subjects

R Schunk

Publications and source records attributed to R Schunk.

4 recordsLinked to original sources

PubMed2004

Metabolic pathway analysis web service (Pathway Hunter Tool at CUBIC).

MOTIVATION: Pathway Hunter Tool (PHT), is a fast, robust and user-friendly tool to analyse the shortest paths in metabolic pathways. The user can perform shortest path analysis for one or more organisms or can build virtual organisms (networks) using enzymes. Using PHT, the user can also calculate the average shortest path (Jungnickel, 2002 Graphs, Network and Algorithm. Springer-Verlag, Berlin), average alternate path and the top 10 hubs in the metabolic network. The comparative study of metabolic connectivity and observing the cross talk between metabolic pathways among various sequenced genomes is possible. RESULTS: A new algorithm for finding the biochemically valid connectivity between metabolites in a metabolic network was developed and implemented. A predefined manual assignment of side metabolites (like ATP, ADP, water, CO(2) etc.) and main metabolites is not necessary as the new concept uses chemical structure information (global and local similarity) between metabolites for identification of the shortest path.

Algorithms↗

PubMed2000

Rapid prototyping of patterned functional nanostructures

Living systems exhibit form and function on multiple length scales and at multiple locations. In order to mimic such natural structures, it is necessary to develop efficient strategies for assembling hierarchical materials. Conventional photolithography, although ubiquitous in the fabrication of microelectronics and microelectromechanical systems, is impractical for defining feature sizes below 0.1 micrometres and poorly suited to pattern chemical functionality. Recently, so-called 'soft' lithographic approaches have been combined with surfactant and particulate templating procedures to create materials with multiple levels of structural order. But the materials thus formed have been limited primarily to oxides with no specific functionality, and the associated processing times have ranged from hours to days. Here, using a self-assembling 'ink' we combine silica-surfactant self-assembly with three rapid printing procedures--pen lithography, ink-jet printing, and dip-coating of patterned self-assembled monolayers--to form functional, hierarchically organized structures in seconds. The rapid-prototyping procedures we describe are simple, employ readily available equipment, and provide a link between computer-aided design and self-assembled nanostructures. We expect that the ability to form arbitrary functional designs on arbitrary surfaces will be of practical importance for directly writing sensor arrays and fluidic or photonic systems.

Journal Article↗

PubMed1990

[Lotheissen-McVay repair of hernia. Late follow-up analysis after 1202 operations for inguinal and femoral hernias].

Of 1202 hernia repairs performed according to the modified Lotheissen-McVay technique 1020 (84.9%) were followed up. The frequency of hernia increases with increasing age. The total recurrence rate after an average follow-up of 9 years was 9.2% for primary hernias and 11.5% for recurrences. The recurrence rate depends on the follow-up time and on sex. For primary hernias the recurrence rate was 0.7% after 1 year, 5% after 5 years, 9.1% after 10 years and 11.5% after 15 years. After 1 year the recurrence rate was 0.6% for women and 0.8% for men; after 5 years the corresponding figures were 3.9% and 5.2% and after 10 years, 6.6% and 9.5%. The results after repair of recurrent hernias are not much worse than those obtained in the case of primary hernias. The recurrence rate depends on the surgeon's experience. We found a recurrence rate of 3.6% in 319 operations performed by our most experienced surgeon, as against 16.3% among those performed by inexperienced surgeons. Therefore, careful assistance is paramount for the inexperienced surgeon, because training is indispensable. The most frequent complications of primary operations were hematoma and seroma (4.4%), wound infections (1.7%), pulmonary embolism (0.9%), deep vein thrombosis (0.7%) and testicular atrophy (0.4%). The traditional Lotheissen-McVay technique for hernia repair still has a place in the surgical treatment of hernia. This technique can be used as the standard treatment for all kinds of inguinal or femoral hernias, without higher complication rates, and it yields especially good results in recurrent hernias.

Adolescent↗

PubMed1976

[Experimental comparison of the tuberculostatic activities of INH, INHG and INHG-Na (author's transl)].

In a comparative experimental study the glucuronic acid derivatives of isonicotinoylhydrazone (INH), isonicotinoyl-hydrazone d-glucuronic acid lactone (INHG, Gluronazid) and INH-sodium glucuronid (INHG-N-A, Gluronazid pro infusione) were shown to have the same tuberculostatic activity as INH both in vitro and in vivo. As judged by the serum inhibitory activity the serum level shows a different temporal pattern. After the administration of INHG or INHG-Na, the inhibitory activity reaches its peak later than does INH but remains in the active range essentially longer. The most substantial and, with regard to therapy, most significant difference between INHG or INHG-Na and INH lies in the varying toxicological properties. Both the oral and intravenous LD50 increase in the sequence INH, INHG and INHG-Na. The i.v. LD50 of INHG-Na exceeds the oral LD50. As compared to INH the lower toxicity permits a higher dosage of gluronazide. Thus a continuously higher serum inhibitory activity can be achieved than with a corresponding INH therapy.

Administration, Oral↗