Enhanced meta-modelling technique for analysis of mode crossing, mode veering and mode coalescence in structural dynamics

In this paper, an enhanced meta-modelling procedure for the approximation of structural eigenfrequencies and eigenvectors is introduced. The procedure allows for correct prediction of the modal parameters in case of mode crossing, veering, and coalescence phenomena that can be observed when variations of the structural parameters occur. The procedure overcomes the erroneous approximation of these phenomena which results from a direct approximation of the modal parameters. The methodology is based on the response surface approximation of the structural matrices and on the concept of modal reduction. A comparison with a direct response surface approximation of the eigenfrequencies shows a considerable improvement in the accuracy as it is presented for a finite element frame structure.     

cis-Diaminedichloroplatinum(II) complexes reversibly bound to water-soluble polyaspartamide carriers for chemotherapeutic applications. II: Platinum coordination to ethylenediamine ligands attached to poly(ethylene oxide)-grafted carrier polymers

In continuation of previous investigations aiming at the development of macromolecular metal complexes for biomedical use, this communication describes poly(alkylene oxide)-grafted polymeric platinum complexes. The platinum-containing macromolecules are obtained from presynthesized polyaspartamide carriers bearing poly(ethylene/propylene oxide) side chains and hydroxyethyl side groups as hydrosolubilizing units in addition to ethylenediamine side group terminals for metal coordination. Platination is brought about by treatment of the carriers with tetrachloroplatinate(II) ion in aqueous solution at 25–60°C. pH 4–6. The polymeric products, purified by dialysis in aqueous solution, are isolated by freeze-drying in yields of 60–80%. Platinum contents are in the range of 4–15%. The metal is bound to the carrier through chelation with the ethylenediamine ligands, forming square-planarcis-dichloroethylenediamine-platinum(II) complex species as side-chain terminals. Initially, the product polymers dissolve smoothly in water. Although on room-temperature storage in the solid state they gradually turn insoluble as a consequence of intermolecular solid-state interaction, solubility is retained on low-temperature storage and in frozen aqueous solutions.     

Diagnosis of idiopathic myositis: value of 99mtechnetium pyrophosphate muscle scintigraphy and magnetic resonance imaging in targeted muscle biopsy

The widespread use and dramatic success of prosthetic joint implant surgery (arthroplasty) has greatly improved the quality of life for many individuals suffering from degenerative, arthritic, or injured joints. However, in a number of cases, recipients experience discomfort at the arthroplasty site that can signal biomechanical failure, or periprosthetic infection of the joint, or both. In fact, infection remains a devastating obstacle, preventing arthroplasty from being an almost perfect medical procedure. Existing tests for the diagnosis of infection in orthopedics are disappointing because of the relatively high frequency of false negative results. To overcome this shortcoming, and to reduce the number of infected revision arthroplasties, a methodology based on molecular biology has been established. The method allows the rapid, sensitive and accurate diagnosis of orthopedic infections, and should aid the clinician with treatment regimens, surgical decisions, and overall patient management in the growing arthroplasty population.     

Cartilage destruction in small joints by rheumatoid arthritis: assessment of fat-suppressed three-dimensional gradient-echo MR pulse sequences in vitro

In this study the small-intestine phenotype in rat colonic tumors was investigated in terms of sucrase and intestinal-type alkaline phosphatase (I-ALP) activity. F344 rats were given intraperitoneal injections of methylazoxymethanol acetate at a dose level of 25 mg/kg body weight once a week for 8 weeks and were killed 40 weeks after the first injection. Sucrase and I-ALP activities in proximal and distal colon adenocarcinomas were significantly higher than those in the normal colon epithelium. In the jejunum, by contrast, normal tissue had significantly higher levels than tumors. Immunohistochemical staining of I-ALP was also strong in striated cell borders of colon adenocarcinoma cells. These data suggest that, whereas absorptive cells of the small intestine lose their own traits with tumor development, colonocytes acquire phenotypic features of the small intestine. Intestinal enzymes associated with the striated-cell border, such as sucrase and I-ALP, may be useful markers for malignant phenotypic expression in colonocytes.     

Crosslinking of atactic polypropylene by the system peroxide-pentaerythritol tetraallyl ether

The influence of the concentration of peroxide (mainly dicumyl peroxide) and pentaerythritol tetraallyl ether as coagent and the effect of temperature on the crosslinking of atactic polypropylene (a-PP) with molar mass 12 000g/mol were investigated. Using this system, crosslinking of 40mass% of a-PP at 160°C was obtained. The problems associated with the mechanism for crosslinking of a-PP are discussed.     

Progressive scapulothoracic subluxation after fracture of the clavicle

Fracture of the clavicle is a common injury that usually heals without consequence. Instability of the scapulothoracic articulation does not usually occur. In this case, the scapulothoracic subluxation was not obvious at the time of injury, but progressively worsened over the following 2 weeks. Open reduction and internal fixation of the clavicle fracture restored stability to the shoulder girdle. The patient went on to regain full function of her injured extremity.     

Zur Optimierung der Synthese von Poly(p-phenylen-1,3,4-oxadiazol) in Oleum

By a new technique for the addition of monomers it is possible to increase the reproducibility of the synthesis of poly(1,4-phenylene-1,3,4-oxadiazoles) by one order of magnitude in relation to the known method, measured by the standard deviation of the relative viscosity of polymer solutions in concentrated sulfuric acid. This method leads to polymers with very high molecular weights under markedly milder reaction conditions and in shorter reaction times than by the classic method. The influence of the most important reaction parameters on the reaction rate and equilibrium of the polycondensation was investigated. An [η]/M_w-relation was established based on light-scattering and viscometric investigations of polymer solutions in concentrated sulfuric acid.     

New thermoelectric components using microsystem technologies

This paper describes the first thermoelectric devices based on the V-VI-compounds Bi/sub 2/Te/sub 3/ and (Bi,Sb)/sub 2/Te/sub 3/ which can be manufactured by means of regular thin film technology in combination with microsystem technology. Fabrication concept, material deposition for some 10-/spl mu/m-thick layers and the properties of the deposited thermoelectric materials will be reported. First device properties for Peltier-coolers and thermogenerators will be shown as well as investigations on long term and cycling stability. Data on metal/semiconductor contact resistance were extracted form device data. Device characteristics like response time for a Peltier-cooler and power output for a thermogenerator will be compared to commercial devices.