Die Brainstormers: Entwurfsprinzipien lernfähiger autonomer Roboter

Zusammenfassung Das “Brainstormers” Projekt wurde 1998 gestartet mit dem Ziel, lernfähige autonome Agenten in komplexen Umgebungen am Beispiel Roboterfußball zu erforschen. Dabei hat die Bearbeitung der vielfältigen Fragestellungen, die sich in dieser sehr dynamischen und verrauschten Umgebung ergeben, zu einer Vielzahl neuartiger Methoden und theoretischer Ergebnisse geführt.     

A new method of measuring renal function in conscious rats without the use of radioisotopes

The purpose of the current experiment was to develop fast and accurate assays for measuring glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). An enzymatic method was developed for the determination of inulin, and a colorimetric method was developed for determination of p-aminohippurate (PAH) in the plasma and urine of rats. These assays are easily automated and do not require the use of radioisotopes or corrosive chemicals. Glomerular filtration rate was measured by the clearance of inulin, and effective renal plasma flow was measured by the clearance of PAH. Blood pressure, heart rate, and renal function (urine volume, electrolytes, GFR, and ERPF) were measured in conscious rats for 1.5 h prior to drug treatment and for 3 h after treatment. Baseline renal function was compared to historical data. Acute changes in GFR and ERPF following administration of the vasoconstrictor peptide endothelin-1 (ET-1) were accurately measured with results similar to those obtained with older methodologies. These new methods offer many advantages over previously described methods by eliminating the use of radioisotopes and harsh chemicals. In addition, these methods can be used with an automated instrument with high accuracy and precision. Therefore, these new methods can be used to accurately determine GFR and ERPF and are sensitive enough to detect acute changes in GFR and ERPF in conscious animals.     

Distribution and balance of volatile halogenated hydrocarbons in the water and air of covered swimming pools using chlorine for water disinfection

A survey of the “chlorination practice” of swimming-pool waters is presented taking the case of covered pools in Bremen. Chlorination of water may result in specific health hazards by various halogenated chemicals. Trihalomethanes (THMs), among others, are determined in water and air samples. We succeeded in identifying one organic “precursor” of the synthesis of THMs in swimming pools. An estimate of the average and maximum burden of the user/swimmer is given. Short and long range alternative measures are proposed to diminish the health hazards. We conclude from this work that the application of chlorine for disinfection should be minimized.     

Biological evidence of an oviposition-deterring pheromone inLobesia botrana Den. et Schiff. (Lepidoptera,Tortricidae)

Females of the European grapevine moth (Lobesia botrana Den. et Schiff.) usually deposit isolated eggs on flowers and berries of the grapevine (Vitis vinifera L.). We have investigated whether an epideictic pheromone could be present on the egg surface to explain this spacing behavior. About 21,000 eggs ofL. botrana were washed in cold methanol, and the biological activity was tested in a two-choice bioassay offering treated and nontreated areas. Different dilutions of the extract were tested in methanol, which was inactive alone. At the dose of four egg equivalents per microliter of extract, the number of eggs laid by theL. botrana females was reduced by as much as 57% on the treated areas compared to nontreated areas. A longer-term suppression of oviposition (at least 24 hr) following an exposure to the extract occurred for two doses (0.6 and 4.0 eggs/l) of egg extract. Our results strongly suggest the occurrence of an oviposition-deterring pheromone (ODP) on the eggs ofL. botrana. The ecological value of these results is discussed.     

Molecular cloning, expression, and functional significance of a cytochrome P450 highly expressed in rat heart myocytes

A cDNA encoding a P450 monooxygenase was amplified from reverse transcribed rat heart and liver total RNA by polymerase chain reaction using primers based on the 5'- and 3'-end sequences of two rat pseudogenes, CYP2J3P1 and CYP2J3P2. Sequence analysis revealed that this 1,778-base pair cDNA contained an open reading frame and encoded a new 502 amino acid protein designated CYP2J3. Based on the deduced amino acid sequence, CYP2J3 was approximately 70% homologous to both human CYP2J2 and rabbit CYP2J1. Recombinant CYP2J3 protein was co-expressed with NADPH-cytochrome P450 oxidoreductase in Sf9 insect cells using a baculovirus expression system. Microsomal fractions of CYP2J3/NADPH-cytochrome P450 oxidoreductase-transfected cells metabolized arachidonic acid to 14,15-, 11,12-, and 8, 9-epoxyeicosatrienoic acids and 19-hydroxyeicosatetraenoic acid as the principal reaction products (catalytic turnover, 0.2 nmol of product/nmol of cytochrome P450/min at 37 degrees C). Immunoblotting of microsomal fractions prepared from rat tissues using a polyclonal antibody raised against recombinant CYP2J2 that cross-reacted with CYP2J3 but not with other known rat P450s demonstrated abundant expression of CYP2J3 protein in heart and liver. Immunohistochemical staining of formalin-fixed paraffin-embedded rat heart tissue sections using the anti-CYP2J2 IgG and avidin-biotin-peroxidase detection localized expression of CYP2J3 primarily to atrial and ventricular myocytes. In an isolated-perfused rat heart model, 20 min of global ischemia followed by 40 min of reflow resulted in recovery of only 44 +/- 6% of base-line contractile function. The addition of 5 microM 11, 12-epoxyeicosatrienoic acid to the perfusate prior to global ischemia resulted in a significant 1.6-fold improvement in recovery of cardiac contractility (69 +/- 5% of base line, p = 0.01 versus vehicle alone). Importantly, neither 14,15-epoxyeicosatrienoic acid nor 19-hydroxyeicosatetraenoic acid significantly improved functional recovery following global ischemia, demonstrating the specificity of the biological effect for the 11, 12-epoxyeicosatrienoic acid regioisomer. Based on these data, we conclude that (a) CYP2J3 is one of the predominant enzymes responsible for the oxidation of endogenous arachidonic acid pools in rat heart myocytes and (b) 11,12-epoxyeicosatrienoic acid may play an important functional role in the response of the heart to ischemia.     

A clinical perspective on lameness originating in the carpus

Clinical experience continues to expand our understanding of the pathophysiology of pain and injury within the carpal joints. The anatomical and physiological capacity of the equine carpus to neutralise loading stress plays a significant role in the prevention of carpal injury. The ability of joint surfaces to dissipate axial force by transfer to the interosseous ligaments is the principal means by which carpal injury is avoided. In the medial aspect of the intercarpal joint and the dorsal aspect of the radial carpal joint, however, the effects of chronic maximal stress and isolated acute supraphysiological loads cannot be neutralised. Progressive osseous remodelling and stress induced changes within the bone, which outstrip its ability to accommodate increasing loads, lead to the loss of structural integrity and fracture in horses in training.     

Relationship between weight gain and lymph flow in dog lungs

Lung weight is a useful indicator of increases in lung extravascular volume. In addition, the lung lymph flow rate (QL) is an important factor in lung fluid balance. We have studied the weight and QL responses to elevations in capillary pressure (Pc) in intact dog lung lower left lobes. We measured lobe weight continuously. We also measured QL from small lymph vessels from the same lobes. The base-line QL was 1.7 +/- 1.5 microliter/min, and the weight was constant. After we increased Pc by 8-20 cmH2O, both weight and QL increased transiently. In most lungs the weight reached a new steady state. When we increased Pc further, weight increased continuously; however, QL reached a plateau. The continuous weight gain was due to edema. These results show that weight and QL respond similarly in nonedematous lungs; however, the weight and QL responses in edematous lungs may be different.