Different C-C coupling reactions of permethyltitanocene and permethylzirconocene with disubstituted 1,3-butadiynes

Herein we describe different C-C coupling reactions of permethyltitanocene and -zirconocene with disubstituted 1,3-butadiynes. The outcomes of these reactions vary depending on the metals and the diyne substituents. The reduction of [Cp2*MCl2] (Cp* = C5Me5; M = Ti, Zr) with Mg in the presence of disubstituted butadiynes RC triple bond C-C triple bond CR' is suitable for the synthesis of different C-C coupling products of the diyne and the permethylmetallocenes, and provides a new method for the generation of functionalized pentamethyl-cyclopentadienyl derivatives. For M = Zr and R = R' = tBu, the reaction gives, by a twofold activation of one pentamethylcyclopentadienyl ligand, the complex [Cp*Zr[-C(=C=CHtBu)-CHtBu-CH2-eta5-C5Me3-CH2-]] (3), containing a fulvene ligand that is coupled to the modified substrate (allenic subunit). When using the analogous permethyltitanocene fragment "Cp2*Ti", the reaction depends strongly on the substituents R and R'. The coupling product of the butadiyne with two methyl groups of one of the pentamethylcyclopentadienyl ring systems, [Cp*Ti[eta5-C5Me3-(CH2-CHR-eta2-C2-CHR'-CH2)]], is obtained with R = R' = tBu (4) and R = tBu, R' = SiMe3 (5). In these complexes one pentamethylcyclopentadienyl ligand is annellated to an eight-membered ring with a C-C triple bond, which is coordinated to the titanium center. A different activation of both pentamethylcyclopentadienyl ligands is observed for R = R' = Me, resulting in the complex [[eta5-C5Me4(CH2)-]Ti[-C(=CHMe)-C(=CHMe)-CH2-eta5-C5Me4]] (6), which displays a fulvene as well as a butadienyl-substituted pentamethylcyclopentadienyl ligand. The influence exerted by the size of the metal is illustrated in the reaction of [Cp2*ZrCl2] with MeC triple bond C-C triple bond CMe. Here the five-membered metallacyclocumulene complex [Cp2*Zr(eta4-1,2,3,4-MeC4Me)] (7) is obtained. The reaction paths found for R = R' = Me are identical to those formerly described for R = R' = Ph.

An ISFET-algal (Chlamydomonas) hybrid provides a system for eco-toxicological tests

A cellular sensoring system was designed in which metabolism-dedicated pH-ISFETs and the unicellular green alga Chlamydomonas reinhardtii as a biological component, were combined. The system permits on-line detection of pH changes caused by the metabolic and photosynthetic activities of the cells. Photosynthetic activity results in a basification of the medium caused by uptake of CO2. In darkness, an acidification of the medium, resulting from the production of CO2 by degradation of starch was observed. Both, acidification and basification, are sensitive indicators for the physiological activity of the alga. Experiments using inhibitors of energy metabolism or photosynthesis illustrate the utility of this system for an on-line monitoring of substances of eco-toxicological importance.

Polar drug residues in sewage and natural waters in the state of Rio de Janeiro, Brazil

The drug residues of lipid regulators, anti-inflammatories and some drug metabolites have been detected in raw sewage, treated waste water and river water in the state of Rio de Janeiro, Brazil. These residues are mainly derived from humans via excretion. The median concentrations in the effluents of sewage treatment plants (STPs) of most drugs investigated in this study ranged from 0.1 to 1 microgram/l. The removal rates of individual drugs during passage through a Brazilian STP varied from 12 to 90%. As a consequence of the incomplete removal of these residues during passage through a STP, rivers were also found to be contaminated. Median concentrations ranged from between 0.02 and 0.04 microgram/l in river water, whereas the maximum values were observed to be up to 0.5 microgram/l.

On-line control of cellular adhesion with impedance measurements using interdigitated electrode structures

Critical parameters to be assessed in cell culture are the number of viable cells and cell viability. Growth, product formation, toxicity effects and the overall success of cell culture can depend largely on these. With interdigitated electrode structures (IDES) adherent cells are cultured directly on a pair of interdigitated electrodes, and the impedance of the system gives insight into the adhesive behaviour of the cells. The signal is influenced by the changes in number, growth and morphological behaviour of adherently growing cells, mainly owing to the insulating effects of the cell membranes. Five different cell lines are used, and their divergent behaviour is monitored over a period of four days, from inoculation of the cells to killing of the cells at the end of the experiments. Even when the cells from close monolayers, great fluctuations in the impedance signal can be observed. Nevertheless, for a more complete description of cellular systems, other parameters, such as acidification and respiration, have to be included in the measuring system.

Monitoring of cellular signalling and metabolism with modular sensor-technique: the PhysioControl-Microsystem (PCM)

Microsensors provide instruments particularly suited for the noninvasive analysis of cell and tissue cultures. The outstanding benefit lies in the passive behaviour of continuously working transducers, which in turn allows the dynamic recording of function-specific cellular processes. The microsensor system presented in this paper is a modular arrangement of various planar and non-planar sensor elements surrounding small cell culture chambers. An optic access to the cultures (e.g. for high resolution light microscopy and spectro-photometric techniques) enables a parallel and comparative data acquisition. The system was originally designed for biomedical research in chemotherapy and pharmacology but it proved to be an effective device both for toxicological and environmental research.

The three-dimensional determination of internal loads in the lower extremity

A three-dimensional model of the lower limb containing 47 muscles was developed to study the differences between a two- and three-dimensional approach for determining internal loads, the role of the dynamic joint representation, and the behavior of different load-bearing criteria in walking and running. The problem of redundancy of the musculo-skeletal system was resolved by applying inverse dynamics and static optimization methods. Different hypothetical load-bearing capabilities of hinge, spherical and intermediate joint types for the knee and the ankle joints were tested. It was found that even almost planar movements such as walking and running are associated with significant three-dimensional intersegment moments, especially in the frontal plane. Thus, a two-dimensional approach may underestimate internal loads up to 60%. It is shown that pure hinge joints are inappropriate for modeling the dynamical joint function of the knee and ankle joints. A more flexible joint representation in combination with a squared muscle stress minimization criterion predicted a lot of synergistic as well as antagonistic muscle activation which was also found in the EMG patterns. The results indicate the importance of muscular joint stabilization in natural human movements. Compared to in vivo measurements it is speculated that the predicted force magnitudes are considerably overestimated due to error propagation and still insufficient anatomical models. Thus, increased efforts to improve further the reliability of internal load calculations should be made in the future.

Influence of inertia on intersegment moments of the lower extremity joints

The calculation of three-dimensional intersegment moments of the lower extremity modelled as a system of rigid bodies-during human locomotion with the help of an inverse dynamics approach is one of the main strategies to describe the local kinetics of a human motion. From the numerical point of view, the resultant intersegment moment consists of different contributions; the moment of ground reaction force, the moment dependent on the weights of the segments and two inertia dependent parts, the moment of inertia force and the rate of change of angular momentum (with respect to the segments centre of gravity). For running with a horizontal velocity of 5 m s(-1), the calculation of the moment of inertia force can be neglected for the ankle but is important for the hip. Looking at the knee, this contribution is needed if the touch down phase is of special interest. The rate of change of angular momentum-with respect to the segments centre of gravity-can be neglected for all joints of the lower extremity.

Monitoring of cellular behaviour by impedance measurements on interdigitated electrode structures

A new method for on-line and real-time monitoring of concentration, growth and physiological state of cells in culture is described. This biosensor is based on impedance measurements of adherently growing cells on interdigitated electrode structures (IDES). The measurements can be performed for several days as there is no detectable electrical influence on the cells. The versatility of this new sensor is shown with some exemplary experiments. Cell density, growth and long-term behaviour of cells on the electrodes clearly change the impedance of the IDES. Both, the global influence of serum components (deprivation of foetal bovine serum) and the toxic effects of heavy metal ions (cadmium) result in changes of the sensor signal and can be visualized.

A new fast and fault-tolerant identification algorithm for spectral databases

A new method for an automatic, computer and database driven identification of UV/VIS spectra is described. It is shown that an identification algorithm must consider the spectral differences as well as their common features. The described identification method allows identifications, even if the spectra are distorted or shifted.

[Microsensory systems in cell biology basic research and medical diagnostics]

The development of an integrated sensor system, called the physiocontrol microsystem, is presented. It is suited for microscopy, and works with both adherent cell types and cultures growing in suspension, as well as with tissue biopsies. The central part, a miniaturized culture chamber equipped with differently constructed microsensors, allows continuous observation of important physiological parameters even in the course of long-lasting experiments. Besides a description of the physical components, the study provides a summary of selected applications of the physiocontrol microsystem in basic cellular research and biomedical diagnostics.

A new shape-oriented classification method for UV/VIS-spectra

A new shape-oriented classification method is described. It is shown, how shapes of UV/VIS-spectra can be classified and coded and how a classification technique can be used to improve database search operations for pre-selections or even shape-oriented identifications.

[Biomechanical stress analysis of the lower extremity]

Within the field of prevention and rehabilitation, a detailed knowledge of the internal stresses and strains, for example the forces acting on and within joints, muscular force, is desirable or indispensable. The complex analysis of movements described here is based on a biomechanical model that takes into account the results of research done by F. Pauwels showing that muscular activity helps reduce the loading of tubular bones. The principle of functional adaptation provides a reasonable explanation for the "muscular redundence" of the locomotory system, and forms the basis for the calculation of internal loads. The results of the analysis include muscular and joint forces and the stresses within femur and tibia. The required anatomical data were for the most part obtainable directly from the test subject by magnetic resonance imaging. The calculated muscular forces are in good agreement with EMG measurements.