The appearance of malignant cells in body fluids like urine, blood or body-cavity fluids are a cl... more The appearance of malignant cells in body fluids like urine, blood or body-cavity fluids are a clear indication for the existence of a tumor and urine or body-cavity fluid cytology are routine diagnostics today. Cytologic examination of the cellular features of fluids is a valuable adjunct to patient diagnosis and the staging and management of tumors. The German-language literature contains the earliest references to the cytology of malignant cells in fluid specimens. Preparation of the specimen has evolved from unstained wet smears to protocols that generally include centrifugation and the generation of stained smears and a cell block. The smears may be alcohol-fixed direct smears, cytospins, or a liquid-based preparation, and they are usually stained with the Papanicolaou method. Additional techniques, such as immunocytochemistry and flow cytometry, provide significant help in this differential diagnosis. Evaluation of microscopic images after Papanicolaou staining eluded digital pathology, an image-based information environment enabled by computer technology that allows for extracting information from a digital slide. With the advent of full-slide scanning digital methods are regarded as promising way to achieve better, faster and cheaper diagnosis, prognosis and prediction of cancer and other important diseases. One important feature are combinations with immunostaining, FISH technology etc., to elude additional information from the specimen. Circulating tumor cells (CTCs) can be found in the bloodstream and are always ready to attach to endothelial cells lining blood vessels and extravasate to enter tissues and organs to form a metastatic site. They show plastic phenotype and a small number of these cells undergo the epithelial-to-mesenchymal (EMT) program. De-differentiation and dissemination from the primary tumor is a basic prerequisite for colonization and growth of distant metastasis. Phenotypic and functional plasticity of cancer cells and the ability to adapt permanently to demanding conditions provide great challenge for identification and characterization of CTC´s from blood. Their clear identification and characterization is, however, also an important prerequisite to obtain valuable information for diagnosis and prognosis by downstream analytical methods. A novel platform for identification and morphological characterization of cancer cells in body fluids by digital methods is presented.
Abstract Exciplex formation of triethylamine with ethanol and with deuterated ethanol at low alco... more Abstract Exciplex formation of triethylamine with ethanol and with deuterated ethanol at low alcohol concentrations in hydrocarbon solutions is shown by steady state and time-resolved fluorescence spectroscopy. The observed spectra and the decay kinetics show the appearance of three exciplex structures which can be discriminated by temperature and deuterium isotope effects. The spectrum of the primarily formed 1:1 heterodimer overlaps significantly with the monomer spectrum (spectral shift is 800 cm −1 ) and equivalent associations are found with tetrahydrofuran. The photophysical parameters change only slightly on complexation. Two further exciplex emissions with large spectral shifts compared with the monomer (4500 cm −1 and 9000 cm −1 ) arise at ethanol concentrations above 0.02 M, together with a diminution of the quantum yield. Complexation with non-deuterated ethanol leads primarily to high energy emissive structures and equilibrium is attained, as they decay with a common lifetime. Deuteration of ethanol results in a stabilization of the lowest energy exciplex, which is populated irreversibly. Exciplex structures are discussed, with reference to ab inition model calculations.
Abstract The effects of the excitation wavelength on the quantum yields Q(eaq−) and QF of electro... more Abstract The effects of the excitation wavelength on the quantum yields Q(eaq−) and QF of electron ejection and fluorescence respectively were measured for 4-cyano-N,N-dimethylaniline (CDMA) and related compounds in aqueous solutions. In the case of CDMA no electron ejection was found for excitation of the long-wavelength (1La, 1Lb) band system. At shorter wavelengths (λexc
In 1986 Rumelhart et al., investigated a wide variety of network designs, they announced the disc... more In 1986 Rumelhart et al., investigated a wide variety of network designs, they announced the discovery of a method of enabling a network to learn to discriminate between classes of patterns that are not linearly separable, they called the method backward propagation of errors. The two types, motor and sensory patterns being distinguished by the network are identified to the learning network by the desired output fed to the network in the learning process. Many data records representing the two types were processed by different mathematical modeling approaches. The models coefficients are considered to be the features which would be utilized for discrimination between motor and sensory responses. Then the results were compared to the desired output for each record and the percentage of correct estimations was calculated for each one. Non-linear model results have proven to be the best single model in application on neural networks, which confirms the non-linear behavior of the nervous system.
... 2. Characterization of the 4-phenyl rotation. A further coordinate to locate the absolute min... more ... 2. Characterization of the 4-phenyl rotation. A further coordinate to locate the absolute minimum of HDMPP is rotation of the phenyl group in position 4, and the results are shown in Fig. 4. The solid curve shows the rotation from 40° up to 140° without any geometry restrictions ...
Abstract The emission yields of 1-(N,N-dimethylamino)-2-phenylethane are followed as a function o... more Abstract The emission yields of 1-(N,N-dimethylamino)-2-phenylethane are followed as a function of the excitation energy in solutions in n-hexane, 1,2-dichloroethane, and in ethanol at room temperature. In n-hexane intramolecular exciplex formation is slightly more favoured from the excited amino than the aryl moiety. The conversion from the excited amine to the exciplex is partly quenched by dichloroethane. In ethanolic solutions excited amine does not convert to the lowest aryl π, π∗, but exciplex formation is observed following excitation of both chromophores.
The appearance of malignant cells in body fluids like urine, blood or body-cavity fluids are a cl... more The appearance of malignant cells in body fluids like urine, blood or body-cavity fluids are a clear indication for the existence of a tumor and urine or body-cavity fluid cytology are routine diagnostics today. Cytologic examination of the cellular features of fluids is a valuable adjunct to patient diagnosis and the staging and management of tumors. The German-language literature contains the earliest references to the cytology of malignant cells in fluid specimens. Preparation of the specimen has evolved from unstained wet smears to protocols that generally include centrifugation and the generation of stained smears and a cell block. The smears may be alcohol-fixed direct smears, cytospins, or a liquid-based preparation, and they are usually stained with the Papanicolaou method. Additional techniques, such as immunocytochemistry and flow cytometry, provide significant help in this differential diagnosis. Evaluation of microscopic images after Papanicolaou staining eluded digital pathology, an image-based information environment enabled by computer technology that allows for extracting information from a digital slide. With the advent of full-slide scanning digital methods are regarded as promising way to achieve better, faster and cheaper diagnosis, prognosis and prediction of cancer and other important diseases. One important feature are combinations with immunostaining, FISH technology etc., to elude additional information from the specimen. Circulating tumor cells (CTCs) can be found in the bloodstream and are always ready to attach to endothelial cells lining blood vessels and extravasate to enter tissues and organs to form a metastatic site. They show plastic phenotype and a small number of these cells undergo the epithelial-to-mesenchymal (EMT) program. De-differentiation and dissemination from the primary tumor is a basic prerequisite for colonization and growth of distant metastasis. Phenotypic and functional plasticity of cancer cells and the ability to adapt permanently to demanding conditions provide great challenge for identification and characterization of CTC´s from blood. Their clear identification and characterization is, however, also an important prerequisite to obtain valuable information for diagnosis and prognosis by downstream analytical methods. A novel platform for identification and morphological characterization of cancer cells in body fluids by digital methods is presented.
Abstract Exciplex formation of triethylamine with ethanol and with deuterated ethanol at low alco... more Abstract Exciplex formation of triethylamine with ethanol and with deuterated ethanol at low alcohol concentrations in hydrocarbon solutions is shown by steady state and time-resolved fluorescence spectroscopy. The observed spectra and the decay kinetics show the appearance of three exciplex structures which can be discriminated by temperature and deuterium isotope effects. The spectrum of the primarily formed 1:1 heterodimer overlaps significantly with the monomer spectrum (spectral shift is 800 cm −1 ) and equivalent associations are found with tetrahydrofuran. The photophysical parameters change only slightly on complexation. Two further exciplex emissions with large spectral shifts compared with the monomer (4500 cm −1 and 9000 cm −1 ) arise at ethanol concentrations above 0.02 M, together with a diminution of the quantum yield. Complexation with non-deuterated ethanol leads primarily to high energy emissive structures and equilibrium is attained, as they decay with a common lifetime. Deuteration of ethanol results in a stabilization of the lowest energy exciplex, which is populated irreversibly. Exciplex structures are discussed, with reference to ab inition model calculations.
Abstract The effects of the excitation wavelength on the quantum yields Q(eaq−) and QF of electro... more Abstract The effects of the excitation wavelength on the quantum yields Q(eaq−) and QF of electron ejection and fluorescence respectively were measured for 4-cyano-N,N-dimethylaniline (CDMA) and related compounds in aqueous solutions. In the case of CDMA no electron ejection was found for excitation of the long-wavelength (1La, 1Lb) band system. At shorter wavelengths (λexc
In 1986 Rumelhart et al., investigated a wide variety of network designs, they announced the disc... more In 1986 Rumelhart et al., investigated a wide variety of network designs, they announced the discovery of a method of enabling a network to learn to discriminate between classes of patterns that are not linearly separable, they called the method backward propagation of errors. The two types, motor and sensory patterns being distinguished by the network are identified to the learning network by the desired output fed to the network in the learning process. Many data records representing the two types were processed by different mathematical modeling approaches. The models coefficients are considered to be the features which would be utilized for discrimination between motor and sensory responses. Then the results were compared to the desired output for each record and the percentage of correct estimations was calculated for each one. Non-linear model results have proven to be the best single model in application on neural networks, which confirms the non-linear behavior of the nervous system.
... 2. Characterization of the 4-phenyl rotation. A further coordinate to locate the absolute min... more ... 2. Characterization of the 4-phenyl rotation. A further coordinate to locate the absolute minimum of HDMPP is rotation of the phenyl group in position 4, and the results are shown in Fig. 4. The solid curve shows the rotation from 40° up to 140° without any geometry restrictions ...
Abstract The emission yields of 1-(N,N-dimethylamino)-2-phenylethane are followed as a function o... more Abstract The emission yields of 1-(N,N-dimethylamino)-2-phenylethane are followed as a function of the excitation energy in solutions in n-hexane, 1,2-dichloroethane, and in ethanol at room temperature. In n-hexane intramolecular exciplex formation is slightly more favoured from the excited amino than the aryl moiety. The conversion from the excited amine to the exciplex is partly quenched by dichloroethane. In ethanolic solutions excited amine does not convert to the lowest aryl π, π∗, but exciplex formation is observed following excitation of both chromophores.
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Papers by Gottfried Köhler