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In the process of endourological development a great variety of foreign bodies have been invented besides urinary catheters on which biofilm can be formed. Bacteria in the biofilm are less sensible to antibiotics. An additional problem of medical biomaterials in the urinary tract environment is the development of encrustation and consecutive obstruction. In this review, we tried to sum up the conditions where biofilm formation has a great impact on the development or maintenance of urological infections and on treatment success. Modification of the biomaterial surface seems to be the most promising prevention strategy for bacterial biofilms. Easier methods for diagnosing and quantifying biofilm infection, to develop more specific antimicrobial agents and ideal device surfaces would surely help the fight against biofilm formation.

We present de Haas–van Alphen (dHvA) measurements of different YNi 2 B 2 C single crystals in magnetic fields up to 32 T. At high magnetic fields three different dHvA frequencies could be detected. The lowest frequency, F α , could be well resolved down to lower fields just above the upper critical field. An unexpectedly sudden vanishing of the dHvA signal in the mixed state has been observed.

The specific heat cp of amorphous polycarbonate and amorphous polystyrene has been measured at pressures up to p = 0.7 GPa in the temperature range 0.2K

Both thermal conductivity λ and specific heat cp of amorphous polystyrene were measured in the temperature range 1.7 K K at three different pressure values up to p=0.4 GPa . The thermal conductivity data show that the influence of pressure is most pronounced at the plateau of λ at 2 K K . Fit calculations were carried out to receive values for P γ 2 and W. As pressure is applied the specific heat is clearly reduced below T=20 K .

We measured the dielectric response, e ′( ω )+i e ″( ω ), of polycarbonate (PC) at various frequencies (1–200 kHz) in the temperature range between 40 mK and 300 K. Under the application of hydrostatic pressure (up to 0.6 GPa) the low temperature properties due to two level tunnelling systems could be examined as well as thermally activated processes in the high temperature regime.

SummaryOtorhinolaryngologists have traditionally dealt with the development of therapeutic procedures that can be applied through the natural openings of the body. As such approaches require special surgical instruments and optical aids, feasibility and success of endoluminal therapy were closely connected with progress in medical technology. This paper assesses the current status of ear, nose and throat (ENT) techniques in endoluminal surgery with special regard to the historical development of this field.

Verlaufsvarianten der A. carotis interna werden im Schrifttum mit einer Haufigkeit von 15–40% angegeben. Hauptursache sind dabei degenerative Veranderungen, die zu einer Verlangerung, Schlangelung und Abknickung des Gefases fuhren konnen. Daneben gibt es die selteneren sigmoiden Schleifenbildungen, die als angeborene Anomalie aufzufassen sind. Berichtet wird uber zwei Patienten, bei denen eine derartige Gefasschleife zu einer Vorwolbung der Pharynxwand verbunden mit leichten Schluckbeschwerden gefuhrt hat. Die Moglichkeit einer diagnostischen Fehleinschatzung wird dabei eindrucksvoll belegt. Die Genese sowie die klinische Bedeutung derartiger Gefasschleifen werden anschliesend ausfuhrlich diskutiert.

With different models, the thermal conductivity of composite materials is calculated on the basis of the thermal conductivity of the matrix and filler, of the volume fraction and shape of the fillers and with consideration of the thermal boundary resistance in the temperature range below 20 K. Measurements of the thermal conductivity and specific heat of epoxy resins with different fillers (needle-shape Ag, HTSC powders) in the temperature range 2–80 K are presented. Comparison of the measured and calculated thermal conductivity of these composites shows that above 20 K, the thermal conductivity is determined to a high degree, by the shape of the fillers.

Sorption dynamics of helium, neon and hydrogen on a carbon molecular sieve and activated charcoal were investigated by Temperature Programmed Desorption (TPD) spectroscopy between 10 and 100 K. Results show that energy distribution of the adsorption sites can be interpreted as a Gaussian one to a good approximation. Central values of these energy distributions for the different solid-gas-combinations are between 25 and 100 meV and well coincide with data in literature obtained by other methods.

A newly developed apparatus for Temperature Programmed Desorption spectroscopy (TPD) in the temperature range between 10 and 100 K is presented. It is provided for the investigation of porous solids especially for use in vacuum engineering, for instance activated charcoal and zeolithe. Favoured working regime is a linear temperature schedule with some parts of a Kelvin per minute, but all other schedules and a variation of the heating rate over the factor 10 are also available. The whole measuring process takes place automatically and under computer control – so a simultaneous registration of a large number of measured gases is possible. Es wird eine neuentwickelte Apparatur zur Thermischen Desorptionsspektroskopie (TDS) im Temperaturbereich zwischen 10 und 100 K vorgestellt. Sie ist zur Untersuchung poroser Festkorper, speziell fur vakuumtechnische Anwendungen, wie etwa Aktivkohle und Zeolithe, vorgesehen. Bevorzugter Arbeitsbetrieb ist ein lineares Aufheizen mit einigen Zehntelkelvin pro Minute, jedoch sind beliebige Aufheizprofile und eine um den Faktor 10 veranderliche Aufheizgeschwindigkeit realisierbar. Der gesamte Mesprozes erfolgt automatisch und unter Computer-Kontrolle, so das die simultane Registrierung einer grosen Anzahl von Testgasen moglich ist.

The thermal conductivity and the specific heat of several polymers and related materials are found to be not smooth functions in the temperature range between 30 and 50 K. A low-temperature anomaly is observed. In the same temperature range, the mechanical and dielectric relaxation spectra of many polymers exhibit a cryogenic relaxation. It is suggested that both the cryogenic relaxation process and the anomaly of the thermal properties near 50 K are independent of the detailed chemical composition of the material and arise from the anisotropy of bonding forces in chain-like or network-like structures. Im Temperaturbereich zwischen 30 und 50 K zeigen verschiedene Polymere und verwandte Materialien in der Warmeleitfahigkeit und in der spezifischen Warmekapazitat keinen glatten Verlauf. Im gleichen Temperaturbereich tritt bei vielen Polymeren in den mechanischen und dielektrischen Verlustspektren eine Tieftemperaturrelaxation auf. Wir nehmen an, das beides, der Tieftemperaturrelaxationsprozes und die Anomalie in den thermischen Eigenschaften nahe 50 K, nicht von der konkreten chemischen Zusammensetzung der Materialien abhangen, sondern ihre Ursache in der Anisotropie der Bindungskrafte in den ketten- oder netzwerkartigen Strukturen liegt.

When predicting and altering the properties of composites, one has to consider not only the peculiarities of the components themselves but also the boundary layer between the filler and the polymer matrix. The aim of this paper is to study the influence of the boundary layer on the low temperature thermal conductivity and specific heat of an epoxy resin/particle composite. Measurements of the glass transition temperature and the hardness are interpreted, as obtained from the filler surface, and electron micrographs of the boundary layer are presented.

The thermal conductivity at low temperatures (between 0.5 K and 100 K) was measured for diolmodified epoxies. Diglycidyl ether of bisphenol A (DGEBA) was modified for this purpose by aliphatic diols with the structure HO-(-CH2-)n-OH in the presence of catalyst (either N,N-dimethyl benzylamine or magnesium perchlorate). Sample series with diols of n=4,8 and 12 were synthesized and measured. The results at T

The thermal conductivity of vitreous silica “Suprasil W2” was measured under high hydrostatic pressure (p ⩽1.5 GPa) and at low temperature (4.5 ⩽ T ⩽ 300 K). The investigations show a strong influence of the pressure on the thermal conductivity. The influence of pressure on thermal conductivity of “Suprasil W2” is most pronounced in the plateau region and is not detectable for temperatures above 80 K.

The thermal conductivity of modified epoxy resins was investigated from 0.5 to 80 K. Two series of samples with different cross-link densities were used. The results are discussed.

We present de Haas–van Alphen (dHvA) measurements of the nonmagnetic borocarbide LuNi 2 B 2 C. In the superconducting state below the upper critical field, B c2 , the dHvA signal shows an additional damping. For some field orientations we observe a very strong damping close to B c2 and only a very weak effect at lower fields in the superconducting state. We discuss the origin of the different dampings and their relation to the superconducting gap.

This randomized, double-blind, controlled clinical trial in parallel group design demonstrated equivalent efficacy and tolerability of a hop-valerian preparation compared with a benzodiazepine preparation in patients suffering from sleep disorders according to DSM-IV criteria. Sleep quality, fitness and quality of life were determined by psychometric tests, psychopathologic scales and sleep-questionnaires at the beginning of the therapy, end of therapy (duration 2 weeks) and then 1 week after cessation of therapy. Patients' state of health (4-point scale) and medication tolerability (occurrence of adverse events) were documented. Using the following as parameters "Alphabetischer Durchstreichtest, Feinmotoriktest, Befindlichkeitsskala, Beschwerdeliste, Schlaffragebögen A and B" the differences between beginning and the end of the therapy were analyzed by simultaneous testing of the equality or superiority of the test preparation. The equivalence of both therapies according to sleep quality, fitness and quality of life was proven by a Mann-Whitney-Statistic of 0.50 with a lower boundary of the 95% confidence interval of 0.46. The patients' state of health improved during therapy while showing a deterioration after cessation with both preparations. Withdrawal symptoms, however, were documented with benzodiazepine. Only one adverse drug reaction was reported during this study, namely stomach complaints from both the test and reference medication. This study shows that the investigated hop-valerian preparation in the appropriate dose is a sensible alternative to benzodiazepine for the treatment of nonchronic and non-psychiatric sleep disorders.

Variations of the clinical course of the internal carotid artery are reported with an incidence of 15-40% in the literature. They mainly arise from degenerative lesions leading to elongation, slight coiling, and kinking of the vessel. Besides that, a sigmoid tortuosity represents an occasional congenital anomaly. This article reports two cases of tortuosity of the internal carotid artery which resulted in impressions of the pharyngeal wall and minor globus syndromes. The possibility of false diagnoses is demonstrated. The etiology and clinical significance of these variations are discussed in detail.

The thermal conductivity λ, the specific heat c, the thermal expansion α, the acoustic and dielectric properties of polycarbonate (PC), of polystyrene (PS) and of an epoxy resin were measured in the temperature ranges between 0.1 K and 80 K (λ c) and between 4 K and 300 K (α). The measurements show the typical low-temperature behavior of amorphous solids. Below 20 K the results can be explained in the framework of the soft potential model. Above 20 K with increasing temperature λ, and α show between 30 K and 50 K a distinct decrease in slope of the temperature dependence. The sound velocity shows for PC and PS the typical decrease with increasing temperature. For PC the maximum in the dielectric losses shifts with increasing frequency and at increasing pressure to higher temperature.

Die Magnetresonanzspektroskopie erlaubt nichtinvasive Untersuchungen von Zellkulturen, die im Gegensatz zur aufwendigen HPLC die Analyse von Kinetiken bestimmter Metabolite in einem Experiment zulast. In der vorgestellten Arbeit haben wir ein Perfusionsverfahren entwickelt, das es ermoglicht, Zellen uber langere Zeitraume (bis zu 1 Woche) unter Verwendung von Matrigel mit Nahrstoffen zu versorgen und diese magnetresonanzspektroskopisch zu untersuchen. Dieses Verfahren wurde von uns bereits fur die Analyse des Stoffwechsels von 5-Fluoruracil (5-FU) an verschiedenen Plattenepithelkarzinomzellinien des Kopf-Hals-Bereichs eingesetzt. Dabei konnte die Kinetik des Entstehens der zytotoxischen Fluornukleotide und des Phosphorstoffwechsel der Zellen in einem Experiment beobachtet werden. Erstmals konnte nachgewiesen werden, das einige Zelllinien mehr als 50% des Fluornukleotids Fluoruridintriphosphat in weniger toxische FUDP-Zucker-Verbindungen umwandeln. Uber die Implikationen dieser Ergebnisse fur die Therapie mit 5-FU wurde berichtet.

Measurements of thermal conductivity, specific heat, and dielectric properties of an epoxy resin after electron, gamma, fast-neutron, and thermal-neutron irradiation are presented. The experimental results show the influence of the different types of radiation on the typical amorphous behaviour of the thermal properties. The H2-permeation rate for two types of carbon-fibre-reinforced plastics are presented.

Die systemische Applikation von rekombinantem Tumornekrosefaktor (rTNF) als Einzeltherapeutikum hat im Rahmen klinischer Studien bislang nur geringfugige antineoplastische Effekte gezeigt. Ahnlich enttauschende Resultate wurden bei der Behandlung menschlicher Hals-Kopftumoren erzielt, die auf der Nacktmaus als sogenannte Heterotransplantate etabliert waren.

Patienten mit fortgeschrittenen Kopf-Hals-Tumoren werden derzeit mehr oder weniger ungezielt mit Platinkomplexen chemotherapiert, wobei man sich an weitgehend festen Behandlungsschemata orientiert. Da die Tumoren jedoch sehr unterschiedlich auf eine derartige Behandlung ansprechen, waren Aussagen uber den voraussichtlichen Therapieerfolg von groser Bedeutung. In den letzten Jahren konnte an heterotransplantierter menschlichen Kopf-Hals-Tumoren in vivo eine enge Korrelation zwischen dem therapeutischen Ansprechen und den Zellzyklusveranderungen nach Gabe von Cisplatin nachgewiesen werden (Cancer Chemother Pharmacol 27:464–471, 1991). Es stellte sich heraus, das in sensiblen Tumoren kurz nach Behandlung Zellansammlungen in der S-Phase auftraten, die stets von einer nachhaltigen antineoplastischen Wirkung gefolgt waren. Resistente Tumoren zeigten derartige Veranderungen dagegen nicht. In der vorliegenden Arbeit sollte untersucht werden, inwieweit diese Korrelation fur Cisplatin auch in vitro Gultigkeit besitzt.

Die klinische Klassifikation von Larynxkarzinomen nach den Kriterien des TNM-Systems der UICC bringt bekanntermasen immer wieder Probleme bei der genauen Einschatzung der Tumorgrose mit sich. Durch ungenaue klinische, subjektive Angaben und durch die Gleichsetzung von klinischen und pathohistologischen Kategorien werden die Tumorgrenzen nur unzureichend definiert. Durch die mangelnde Separierung der Stadien sind prognostische Aussagen nur bedingt moglich.

This empirical study is based on 285 standardized interviews with older people living in government-subsidized housing (sozialer Wohnungsbau). Housing conditions, especially contentment and perceived deficiencies are described. Additional remarks refer to the neighborhood relations. The high contentment, already known from former studies, is confirmed by the results. The findings indicate that steps towards an adaptation of housing conditions to possible needs of older people are not ranked very high. Beyond that, there seems to be a lack of information about the technical possibilities of improving the housing conditions, although older people want to live as long as possible in their current housing.

We have measured the dielectric response e(ω) and the thermal conductivity κ of polystyrene (PS) and of polycarbonate (PC) under high hydrostatic pressure (0.1 MPa MPa ) and at low temperatures ( 50 mK K ). The investigations show a pressure influence on the minimum temperature of Δe′/e′ and on κ. With the pressure dependence of the density and sound velocity of PC and PS the influence of pressure on the tunnelling constant Ci can be determined. These results show that the product P γ l,t 2 of the standard tunnelling model (STM) scales with the pressure-dependent elastic constants c11 and c44.

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The thermal conductivity λ, the specific heat c and the thermal expansion α of isotropic Polycarbonat (PC) and of PC after stretching were measured in the temperature ranges between 0.1 K and 80 K (λ, c) and between 4 K and 300 K (α). The measurements show the typical low-temperature behavior of amorphous solids. Below 20 K the results can be explained in the framework of the soft potential model. Above 20 K with increasing temperature the thermal conductivity and the thermal expansion show between 30 K and 50 K a distinct decrease in slope of the temperature dependence. PC, stretched at 438 K with a load of 2 kN, shows a high anisotropy in these two thermal properties.

We measured the thermal conductivity λ of Polycarbonat (PC) in the temperature range from 3 K to 150 K under application of hydrostatic pressure up to 1.3 GPa. A strong influence of pressure on λ was observed over the entire temperature range. An additional measurement of the pressure dependence of density showed that the density of PC increases appreciably with pressure. The thermal conductivity data were thus corrected considering the changes of density. The corrected data show an increase of λ with pressure only in the plateau region of thermal conductivity. Similar results were measured for vitreous silica [1] and epoxy resin [2], where the data of vitreous silica show an opposite behaviour of λ with increasing pressure.

The thermal conductivity and the specific heat of pure and filled epoxy resins are measured in the temperature range between 2 and 80 K. In order to study the low-temperature thermal conductivity of the filled samples without any acoustic mismatch a filler completely identical with the matrix material is used. The characteristic plateau of the thermal conductivity of amorphous solids between 5 and 15 K is extented to elevated temperatures with growing filler content. A second plateau of the thermal conductivity between 30 and 50 K is observed. It is suggested that the second plateau arises from a mechanism which is due to the anisotropic bending forces in polymers and related materials.

Mesergebnisse der Warmeleitfahigkeit von reinem und kreidegefulltem Polyethylen hoher Dichte zwischen 2 und 20 K werden vorgestellt. Die Abweichungen zwischen gemessenen und aus Mischungsformeln berechneten Warmeleitfahigkeiten sind auf Aggregatbildung von Fullstoffpartikeln zuruckzufuhren. Ausgehend davon wird vorgeschlagen, Warmeleitfahigkeitsmessungen bei tiefen Temperaturen zur quantitativen Bestimmung der Aggregatbildung in gefullten Polymeren zu benutzen.

The thermal condcutivity and specific heat of amorphous, non-oriented polycarbonate were measured in the temperature range between 2 and 80 K. The temperature dependence of the thermal conductivity below 20 K indicates the presence of heterogeneities. The specific surface of these heterogeneities is estimated from the phonon mean free path length. The heterogeneous structure is preserved when the material is heated above the glass transition temperature. Die Warmeleitfahigkeit und die spezifische Warmekapazitat von amorphem, nichtorientiertenl Polycarbonat wurden bei Temperaturen zwiscken 2 und 80 K gemessen. Die Temperaturabhangigkeit der Warmeleitfahigkeit unterhalb von 20 K zeigt das Vorhandensein von Heterogenitaten an, deren spezifische Oberflache aus der mittleren freien Weglange der Phononen abgeschatzt wird. Die heterogene Struktur bleibt nach Erwarmen des Materials aber die Glasabergangstemperatur erhalten.

Measurements of the thermal conductivity and of the dielectric properties of an electronirradiated epoxy-resin are presented. The experimental results for varying radiation doses of structural investigations of electron-irradiated epoxy-resin 1 are discussed.

The quality of the heat contact existing between adsorbent and cooled surface has a decisive influence on pumping speed. By gluing the adsorbent onto the surface by means of a water glass-talcum mixture, the pumping speed, as compared to that of the loose layers, could be increased by a factor of about 200. The pumping speed is not considerably reduced when several load cycles are made with the adsorbent being heated to room temperature only between cycles.

Measurements of the thermal conductivity and of the dielectric properties of an epoxy-resin irradiated by fast and thermal neutrons are presented. The discussion of the experimental results accounts for the radiation dose and energy of neutrons.

The proliferation behavior of three adenocarcinomas derived from the colon rectum, colon sigmoideum and the lung was pursued by flow cytophotometry between 0 h and 38 h after heterotransplantation to athymic mice. On principle, the same pattern of alterations was observed in the case of all three tumors, the time parameters slightly varying in dependence on growth velocity. At first, the number of intact tumor cells markedly decreased during 16-24 h after transplantation, being accompanied by an increase of cellular debris and an immigration of numerous host animal cells; the latter became the quantitatively preponderant portion of cells between days 2 and 8. On day 6, the tumor cell population began to proliferate. At first, the G1 peak rose, followed by the appearance of tumor cells in the S and (G2 + M) phases. Simulataneously, the relative portions of mouse cells and cellular debris diminished. Between days 14 and 30, when maximum rates of macroscopic growth of the heterotransplants were achieved, the cytokinetic features of the xenografts had stabilized and were characterized by the presence of a small portion of mouse cells and a prominent tumor cell population, most cells being in the G1 phase and a smaller number passing through the S and (G2 + M) phases. Beyond day 30, degeneration phenomena again occurred, which were reflected by a decay of mouse and tumor cell populations and a simultaneous increase of cell fragments. By cytokinetic means, the results of the present study reveal a multistep development of human tumors after heterotransplantation into nude mice, and confirm the importance of host-supplied cells for the removal of degenerated tumor cells and the induction of tumor cell proliferation. Moreover, the results show that a stable cytokinetic pattern is found only during the phase of macroscopic tumor growth and the following phase of steady state.

The thermal conductivity λ of polycarbonate (PC) has been measured in the temperature range 3–150 K under hydrostatic pressure up to 1.3 GPa [Geilenkeuser, R., Weise, F. and Jackel, M., Czech. J. Physics , 1996, 46, 2251 ( Proc. LT 21 , Prag, August 1996)]. A strong influence of pressure on λ has been observed over the entire temperature range. Additional measurements of the pressure dependence of the density showed that the density of PC, polystyrene (PS), epoxy resin and PTFE (Teflon) increased considerably with pressure (Jackel, M., Weise, F. and Geilenkeuser, R. In Proc. ICEC16/ICMC , Kitakyushu, May 1996, in press). At a pressure of 1.3 GPa the relative increase of the density amounts to 25%. The thermal conductivity data were corrected for the changes of density, sample geometry and sound velocity. The corrected data show an increase of λ with pressure only in the plateau region of thermal conductivity. Similar results were measured for vitreous silica (Jackel, M., Wagner, K. and Hegenbarth, E., Physica B , 1996, 219&220, 308) and epoxy resin (Grace, J.M. and Anderson, A.C., Phys. Rev. B , 1989, 40, 1901).

The specific adsorption capacity is independent of the thickness up to layer thicknesses of 15 μm, and for thicker layers it decreases. At a given specific load the highest pumping speed is obtained with the thinnest layers. With increasing pressure pumping speed rises at equal absolute load, whereas with equal percentage load a drop is observed. It is possible to regenerate the adsorbent by condensing new layers of carbon dioxide on the charged ones.