bluuebunny/crossref_metadata_2025 huggingface dataset:
RHEOLOGICAL AND ELECTRICAL PROPERTIES OF NaY ZEOLITE ELECTRORHEOLOGICAL FLUID
Authors: QIU Z. Y. , LIU L. W. , WANG Z. W. , ZHOU L. W.
Published: January 2005

The relations between the rheological and electrical properties of NaY zeolite electrorheological fluid and its solid phase are studied. It is found that there exist complex relations between its electrical and rheological properties. The temperature spectra of dielectric properties of the fluid under high AC electric field are strongly field strength dependent. The relation between the DC conductivity of the fluid and the exciting electric field is experimentally presented as log σ= A + BE 1/2, where A is a strong function, but B, a very weak function of temperature. The shear stress of the fluid under a fixed electric field and temperature decreases with shear rate. A relaxation time for the adsorbed charges is estimated to be about 0.3 to 6.6 s in the temperature range from 280 to 380 K. The relaxation time qualitatively corresponds to the shear rate at which the shear stress begins to drop. The time dependent leaking current of the ER fluids under DC electric field is also measured. The conductivity increase is mainly caused by the structure evolution of particles. The experimental results can be explained with the calculations of Davis (J. Appl. Phys.81 (1997) pp. 1985–1991) and Martin (J. Chem. Phys.110 (1999) pp. 4854–4866). It is predicted that the NaY zeolite ER fluid strength would get degraded slowly.
COATED GLASS MICROSPHERES IN ERF APPLICATIONS
Authors: STIPANOVIC ARTHUR J.
Published: January 2005

ER fluids (ERFs) typically consist of a concentrated dispersion of solid particles in a non-conducting base fluid. As a result, particle sedimentation represents a significant problem for many formulations since, in most cases, the particulate phase is of higher density than the base fluid. To remedy this situation, higher density fluids have been widely used in ERFs (ρ > 1.1 g/cc) rather than less expensive mineral oils that display lower densities (0.8-0.9 g/cc). An alternative approach to density "matching" has been explored by Qi and Shaw who have successfully developed ERF particles based on low density, micron-sized hollow glass "balloons" that are polymer coated. These microballons are commercially available from the PQ Corporation and they exhibit an effective density of 0.7 g/cc. Using these materials, it becomes possible to engineer ERF particles that are "neutrally buoyant" in mineral oils by adjusting the coating weight of an ER active polymer on the glass spheres.

In this study, a simple solution coating process was developed exploiting the unique surface chemistry of glass which contains -Si-O-Si- and -Si-OH sites capable of hydrogen bonding with hydrophillic polymers. A number of water-soluble ionic polysaccharides were evaluated as coatings because of their ability to form hydrogen bonds with glass surfaces. A synthetic alcohol-soluble polymer, sulfonated polyphenylene oxide, was also evaluated because of its thermal stability and mechanical durability.
Design and Preparation of a Kind Metal/p (MMA-MAA) ERF
Authors: Luo Chunrong , Tang Hong , Zhao Xiaopeng
Published: January 2005

By the classical electrodynamics, the expression of interaction energy and force between two dipoles located arbitrary orientations are derived. Using direct polymerization method, we have prepared the metal/microcapsule-particles. Meanwhile an electrorheological fluid (ERF) made up by these composite particles is prepared. The ER behaviors were investigated by microscope and mechanical test, it is found that the very visible chain's structure of ERF can observe and the induced yield stress increased with the electric field and the particles' volume fraction.
TWO DIMENSIONAL FLOW OF AN ESF: EXPERIMENT, CFD, BINGHAM PLASTIC ANALYSIS
Authors: BULLOUGH W. A. , ATKIN R. J. , URANG S. , KUM T. G. , MUSCH C. , ROBER T.
Published: January 2005

The two dimensional flow of an electrorheological fluid in a concentric cylinder, Couette type apparatus is investigated at different inter-plate speeds, voltages and axial pressure gradients. Test results at low, but realistic, loading conditions correlate with Bingham plastic computer fluid dynamics (CFD) package predictions, at each field strength. The package had been pre verified against an analytical solution for the same flow field. In all cases the liquid is taken to be isothermal. Indications are that the rate of throughflow should not interfere severely with the voltage set magnitude of torque transmission. Hence the cooling of slipping clutches by through flow can be contemplated. At present the investigation covers only the case of one stationary and one moving plate with no heat transfer or centrifugal terms.
LIGHT SCATTERING STUDY OF PARTICLE DYNAMICS IN DIPOLAR MAGNETIC FLUIDS
Authors: CUTILLAS SERGE , LIU JING
Published: January 2005

Halsey and Toor theoretical model (HT) predicts that a thermally induced long-range chain-chain interaction might be responsible for chain-chain lateral aggregation in dipolar fluids. However, this model fails with experiments. To characterize thermally induced chain vibrations, we measured the dynamics of particles in a chain configuration in a very dilute ferrofluid emulsion using Dynamic Light Scattering (DLS). The transverse particle diffusion coefficient at short times is studied as a function of the scattering wave vector, q, and the coupling constant, λ. By varying q, transverse motions of the whole chain can be well separated from transverse motions of the chain components (particles). The results show that the characteristic frequency of particle position fluctuations scales as [Formula: see text], where a is the particle radius. This is interpreted using a polymer analogy including Hydrodynamic Interactions (HI) known as Rouse-Zimm model. Since HI are not included in HT model, HI could be responsible for the discrepancy with experiments. When the volume fraction increases, chains gather and DLS is inappropriate to study the system. A more recently developed technique, known as Diffusing Wave Spectroscopy (DWS) is used to obtain the mean square displacement of particle within columns. Since the particle dynamics is closely related to the viscoelastic properties of the system, studying particle dynamics may help us to understand better the rheological properties of MR fluids.
Measurement of Interaction Forces at Small Distance under Electric Field in a Smectite Dispersed Silicone Oil Based ER Fluid
Authors: FUJITA Toyohisa , MIYAZAKI Toshio , TANAKA Toshiharu , Liu Ke Jun , KUZUNO Eiich , MUTO Hajime , BEKKALA Andrew
Published: January 2005

The apparatus to measure interaction forces under an electric field at small distance between a conductive hemisphere and a flat plate has been developed. The surface forces at small distance sandwiched ER fluid dispersing ultrafine smectite particles (20 to 50 nm thickness) in silicone oil has been measured. This fluid shows 0.7 kPa of apparent yield stress by applying 2.5 kV/mm of DC electric field. When an electric field applies to this ER fluid, the repulsive energy curves shows inflection points at about 0.2 μ m distance periodically at small distance of less than 1 μ m because the repulsion force decreases for a vacancy of particles after the particles are pushed out and the dipole attraction force acts between hemisphere and plate. On the other hand, when the electric field becomes off and it passes enough time, the inflection points is observed more shorter distance of about 0.15 μ m periodically. The coagulated particle size is estimated about 0.15 μ m under no electric field and becomes larger by applying electric field.
BROWNIAN DYNAMICS ANALYSIS OF MAGNETIC ORDER-DISORDER TRANSITION IN A FERROMAGNETIC COLLOIDAL SYSTEM
Authors: UKAI TOMOFUMI , MAEKAWA TORU , MORIMOTO HISAO
Published: January 2005

We carried out Brownian dynamics simulations of a ferromagnetic colloidal system and investigated the particles' motions and the magnetic structures of the system. The particles' pair correlation functions and the magnetic correlation functions are calculated and the formations of chain clusters and magnetic domains are analysed quantitatively. Investigating the magnetic susceptibility, the specific heat of the system, the magnetic moments' ordering and the magnetisation of the system, the cluster and magnetic characteristics of the highly frustrated ferromagnetic system are made clear.
EVIDENCE OF SECOND ORDER PHASE TRANSITION OF FERROFLUID IN EXTERNAL ELECTRIC FIELD
Authors: Duan Xiaodong , Luo Weili
Published: January 2005

When a DC electric field is applied perpendicular to a thin film of ferrofluid constrained between two conducting plates, the ferrofluid separates into phases that are concentrated and dilute in magnetic particles for field strength above a critical value. The phase separation stems from the competition between the electrostatic energy and entropy of the induced dipoles. The entropy around the critical value of the phase separation is continues in our experiment indicating the transition is second order.
SHEAR BANDED STRUCTURES AND NEMATIC TO ISOTROPIC TRANSITION IN MR FLUIDS
Authors: VOLKOVA O. , BOSSIS G. , CARLETTO P. , CEBERS A.
Published: January 2005

The experimental shear stress versus shear rate curves of MR fluids are analysed with the help of a chain model. Two critical shear rates are found, one corresponding to the onset of agregate breaking and the other corresponding to the total disappearance of aggregates. Above this second critical shear rate we observe an abrupt jump of stress and the onset of a layered stripe pattern. This novel shear induced transition can be observed by using a cone-plate geometry but is usually smeared out in a plate-plate geometry. Still in a plate geometry we also have observed a similar phase separation in ER fluids but without a clear rheological signature. We show that this phase separation can be explained by the transition from a nematic like order induced by the field to an isotropic state which is obtained when the shearing hydrodynamic forces on a pair of particles overcome the magnetic or electrostatic forces. The critical shear stress predicted on this basis is in good agreement with the experimental results. We find a similar layered pattern in a rotating magnetic field. The connection between the two situations is explained.
DYNAMIC SIMULATION OF THE TEMPORAL RESPONSE OF MICROSTRUCTURE FORMATION IN MAGNETORHEOLOGICAL FLUIDS
Authors: LY H. V. , ITO K. , BANKS H. T. , JOLLY M. R. , REITICH F.
Published: January 2005

Efficient numerical simulations of microstructure development in magnetorheological (MR) fluids are conducted. The simulations, which are based upon a fast multipole algorithm, treat the magnetic inclusions as two-dimensional continuum magnetic entities. The development of microstructure is quantified by computing and recording the time evolution of the effective permeability of the composite fluid. Such a principle has been previously exploited for the experimental measurements of microstructure development [Jolly, Bender and Mathers, ERMR'97, Yonezawa, Japan 1997]. As was observed experimentally, numerical simulations reveal the evolution of microstructure to be multimodal in nature. Unlike the experiments, the numerical simulations afford us the ability to observe the physical mechanisms associated with various modes.
ELECTRORHEOLOGICAL FLUIDS UNDER SHEAR
Authors: Tao R. , Zhang J. , Shiroyanagi Y. , Tang X. , Zhang X.
Published: January 2005

The behavior of an electrorheological (ER) chain under a shear force is investigated theoretically and experimentally. Contrary to the conventional assumption that the ER chain under a shear force becomes slanted and breaks at the middle, we have found that there is symmetry breaking. When the shear strain is small, the chain becomes slanted with a space gap between the first and second particles (or between the last and next last particles). As the shear strain increases, the gap becomes wider and wider. When the shear strain exceeds a critical value, the chain breaks at the gap. The experiment also confirms that an ER chain under the shear breaks at either end, not at the middle. This symmetry breaking reflects the space's anisotropy, which is the result of the applied electric field.
PROBING ASPECTS OF NONLINEAR CONDUCTION IN ELECTRORHEOLOGICAL SUSPENSIONS
Authors: RANKIN P. J. , SHKEL Y. M. , KLINGENBERG D. J. , SHOHET J. L.
Published: January 2005

Particle and electrode surfaces were altered to examine the effects on the electrorheological response of barium titanate/silicone oil suspensions. Unmodified suspensions exhibited nonlinear conduction. The dynamic yield stresses scaled as En, where n<2 at all electric field frequencies, and the current had substantial harmonic content, a hallmark of nonlinear conduction. Modifying the particle surfaces did not affect these nonlinear responses. Casting polymers on the electrode surfaces changed the responses. With polymer coatings, the dynamic yield stresses scaled as En, where n≥2 at some frequencies and increased with coating thickness. With coated electrodes, the current harmonic contents were significantly decreased. These results suggest that nonlinear conduction in ER suspensions is associated with charge injection at the electrode/liquid interface.
DIFFERENCES IN STEADY CHARACTERISTICS AND RESPONSE TIME OF ERF ON ROTATIONAL FLOW BETWEEN ROTATING DISK AND CONCENTRIC CYLINDER
Authors: SHIMADA K. , NISHIDA H. , FUJITA T.
Published: January 2005

We made an experimental investigation of the steady characteristics of torque, current density, and response time of ERF on rotational flow of the disk and the concentric cylinder. We used smectite particles suspension ERF and D.C. electric field. We compared the steady shearstress, current density, and the rise and settling time of the concentric cylinder and with those of the rotating disk. Then we clarified the differences. At a larger electric field strength, the shear stress, yield stress, and apparent viscosity to a constant shear rate in the case of the rotating disk are larger than they are in the case of the rotating concentric cylinder. However, at a larger electric field strength, the current density to a constant shear rate in the case of the rotating disk is smaller than it is in the case of the rotating concentric cylinder. Rise time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder. However, rise time of current density in the case of the rotating disk is slower than it is in the case of the rotating concentric cylinder at a small electric field strength. On the other hand, the difference of settling time of torque and current density between the rotating disk and the rotating concentric cylinder is changed by the electric field strength and shear rate. The settling time of torque in the case of the rotating disk is faster than it is in the case of the rotating concentric cylinder at a large electric field strength and large shear rate. The settling time of current density in the case of the rotating disk is slower than it is in the case of rotating concentric cylinder at a small electric field strength. Based on these results, the rotating disk has an efficiency of obtained torque to given electric power greater than that of the rotating concentric cylinder.
HYSTERESIS PHENOMENON IN FLOW-CURVES OF ER FLUIDS CONTAINING SULFONATED POLYMER PARTICLES
Authors: AIZAWA RYUJI , VIEIRA SHEILA L. , NAKANO MASAMI , ASAKO YOSHINOBU
Published: January 2005

The ER fluids containing sulfonated polymer particles were continuously sheared at increasing and decreasing shear rates using a rotary concentric cylinder rheometer and the hysteresis in the up- and down-flow-curves were analyzed. The ER fluids show hysteresis of shear stress and current density. The up-curve (when shear rate increased) was located below the down-curve (when shear rate decreased). As the electric field increased, the area in the hysteresis curves increased. The hysteresis depended on the electric field strength, the time of the applied electric field, the volume fraction of particles and the water content of the particles. Hysteresis phenomenon was explained, based on the formation of agglomerations of dispersed particles in the ER fluid and on changes of the lamellar formations
NONLINEAR DISPLACED FOCK STATE REPRESENTATION
Authors: FAN HONGYI , CHENG HAILING
Published: January 2005

As a generalization of the nonlinear coherent states we construct nonlinear displaced Fock states (NLDFS). In contrast to the ordinary displaced Fock state, two kinds of NLDFS are introduced, which are composed by nonlinear displacing operator on the nonlinear Fock states Df(α)| n>f and [Formula: see text]. The over-completeness relation for NLDFS is obtained by virtue of the generalized technique of integration within an ordered product of operators. Generation of some kind of NLDFS is briefly discussed.
ANALYSIS OF SUNSPOT NUMBER FLUCTUATIONS
Authors: FANCHIOTTI H. , SCIUTTO S. J. , GARCÍA CANAL C. A. , HOJVAT C.
Published: January 2005

Monthly averages of the sunspot number visible on the sun, observed from 1749, Zurich Observatory, and from 1848 other observatories, have been analyzed. This time signal presents a frequency power spectra with a clear 1/fα behavior with α≃0.8±0.2. The well-known cycle of approximately 11 years, clearly present in the spectrum, does not produce a sensible distortion of that behavior. The eventual characterization of the sunspot time series as a fractal is analyzed by means of the detrended fluctuation analysis (DFA). The jump-size distribution of the signal is also studied.
CaM kinase II and phospholamban contribute to caffeine-induced relaxation of murine gastric fundus smooth muscle
Authors: Kim Minkyung , Cho Sang Yun , Han In Soo , Koh Sang Don , Perrino Brian A.
Published: January 2005

Caffeine has been shown to increase the Ca2+ release frequency (Ca2+ sparks) from the sarcoplasmic reticulum (SR) through ryanodine-sensitive stores and relax gastric fundus smooth muscle. Increased Ca2+ store refilling increases the frequency of Ca2+ release events and store refilling is enhanced by CaM kinase II (CaMKII) phosphorylation of phospholamban (PLB). These findings suggest that transient, localized Ca2+ release events from the SR may activate CaMKII and contribute to relaxation by enhancing store refilling due to PLB Thr17 phosphorylation. To investigate this possibility, we examined the effects of caffeine on CaMKII, muscle tone, and PLB phosphorylation in murine gastric fundus smooth muscle. Caffeine (1 mM) hyperpolarized and relaxed murine gastric fundus smooth muscle and activated CaMKII. Ryanodine, tetracaine, or cyclopiazonic acid each prevented CaMKII activation and significantly inhibited caffeine-induced relaxation. The large-conductance Ca2+-activated K+ channel blocker iberiotoxin, but not apamin, partially inhibited caffeine-induced relaxation. Caffeine-induced CaMKII activation increased PLB Thr17, but not PLB Ser16 phosphorylation. 3-Isobutyl-1-methylxanthine increased PLB Ser16 phosphorylation, but not PLB Thr17 phosphorylation. The CaMKII inhibitor KN-93 inhibited caffeine-induced relaxation and PLB Thr17 phosphorylation. These results show that caffeine-induced CaMKII activation and PLB phosphorylation play a role in the relaxation of gastric fundus smooth muscles.
Skeletal muscle contractile performance and ADP accumulation in adenylate kinase-deficient mice
Authors: Hancock Chad R. , Janssen Edwin , Terjung Ronald L.
Published: January 2005

The production of AMP by adenylate kinase (AK) and subsequent deamination by AMP deaminase limits ADP accumulation during conditions of high-energy demand in skeletal muscle. The goal of this study was to investigate the consequences of AK deficiency (−/−) on adenine nucleotide management and whole muscle function at high-energy demands. To do this, we examined isometric tetanic contractile performance of the gastrocnemius-plantaris-soleus (GPS) muscle group in situ in AK1−/− mice and wild-type (WT) controls over a range of contraction frequencies (30–120 tetani/min). We found that AK1−/− muscle exhibited a diminished inosine 5′-monophosphate formation rate (14% of WT) and an inordinate accumulation of ADP (∼1.5 mM) at the highest energy demands, compared with WT controls. AK-deficient muscle exhibited similar initial contractile performance (521 ± 9 and 521 ± 10 g tension in WT and AK1−/− muscle, respectively), followed by a significant slowing of relaxation kinetics at the highest energy demands relative to WT controls. This is consistent with a depressed capacity to sequester calcium in the presence of high ADP. However, the overall pattern of fatigue in AK1−/− mice was similar to WT control muscle. Our findings directly demonstrate the importance of AMP formation and subsequent deamination in limiting ADP accumulation. Whole muscle contractile performance was, however, remarkably tolerant of ADP accumulation markedly in excess of what normally occurs in skeletal muscle.
Autonomic nervous system and blood pressure regulation in RGS2-deficient mice
Authors: Gross Volkmar , Tank Jens , Obst Michael , Plehm Ralph , Blumer Kendall J. , Diedrich Andrè , Jordan Jens , Luft Friedrich C.
Published: January 2005

Regulator of G protein signaling (RGS2) deletion in mice prolongs signaling by G protein-coupled vasoconstrictor receptors and increases blood pressure. However, the exact mechanism of the increase in blood pressure is unknown. To address this question we tested autonomic nervous system function and blood pressure regulation in RGS2-deficient mice (RGS2 −/−). We measured arterial blood pressure and heart rate (HR) with telemetry, computed time and frequency-domain measures for blood pressure and HR variability (HRV) as well as baroreflex sensitivity [BRS-low frequency (LF)], and assessed environmental stress sensitivity. Mean arterial blood pressure (MAP) was ∼10 mmHg higher in RGS2 −/− compared with RGS2 +/+ mice, while HR was not different between the groups, indicating a resetting of the baroreceptor reflex. Atropine increased MAP more in RGS2 −/− than in RGS2 +/+ mice while HR responses were not different. Urinary norepinephrine excretion was higher in RGS2 −/− than in RGS2 +/+ mice. The blood pressure decrease following prazosin was more pronounced in RGS2 −/− mice than in RGS2 +/+ mice. The LF and high-frequency (HF) power of HRV were reduced in RGS2 −/− compared with controls while BRS-LF and SBP-LF were not different. Atropine and atropine + metoprolol markedly reduced the HRV parameters in the time (RMSSD) and frequency domain (LF, HF, LF/HF) in both strains. Environmental stress sensitivity was increased in RGS2 −/− mice compared with controls. We conclude that the increase in blood pressure in RGS2 −/− mice is not solely explained by peripheral vascular mechanisms. A central nervous system mechanism might be implicated by an increased sympathetic tone. This state of affairs could lead to a baroreceptor-HR reflex resetting, while BRS remains unimpaired.
Increased osmolality of conscious water-deprived rats supports arterial pressure and sympathetic activity via a brain action
Authors: Brooks Virginia L. , Qi Yue , O'Donaughy Theresa L.
Published: January 2005

To test the hypothesis that high osmolality acts in the brain to chronically support mean arterial pressure (MAP) and lumbar sympathetic nerve activity (LSNA), the osmolality of blood perfusing the brain was reduced in conscious water-deprived and water-replete rats by infusion of hypotonic fluid via bilateral nonoccluding intracarotid catheters. In water-deprived rats, the intracarotid hypotonic infusion, estimated to lower osmolality by ∼2%, decreased MAP by 9 ± 1 mmHg and LSNA to 86 ± 7% of control; heart increased by 25 ± 8 beats per minute (bpm) (all P < 0.05). MAP, LSNA, and heart rate did not change when the hypotonic fluid was infused intravenously. The intracarotid hypotonic fluid infusion was also ineffective in water-replete rats. Prior treatment with a V1 vasopressin antagonist did not alter the subsequent hypotensive and tachycardic effects of intracarotid hypotonic fluid infusion in water-deprived rats. In summary, acute decreases in osmolality of the carotid blood of water-deprived, but not water-replete, rats decreases MAP and LSNA and increases heart rate. These data support the hypothesis that the elevated osmolality induced by water deprivation acts via a region perfused by the carotid arteries, presumably the brain, to tonically increase MAP and LSNA and suppress heart rate.
Perceptual Continuity and the Emergence of Perceptual Persistence in the Ventral Visual Pathway
Authors: Large Mary-Ellen , Aldcroft Adrian , Vilis Tutis
Published: January 2005

Perceptual continuity is an important aspect of our experience of the visual world. In this study, we focus on an example of perceptual continuity involving the maintenance of figure—ground segregation despite the removal of binding cues that initiated the segregation. Fragmented line drawings of objects were superimposed on a background of randomly oriented lines. Global forms could be discriminated from the background based on differences in motion or differences in color/brightness. Furthermore, perception of a global form persisted after the binding cue had been removed. A comparison between the persistence of forms constructed from motion or color demonstrated that both forms produced persistence after the object defining cues were removed. Functional imaging showed a gradual increase in the persistence of brain activity in the lower visual areas (V1, V2, VP), which reached significance in V4v and peaked in the lateral occipital area. There was no difference in the location of persistence for color- or motion-defined forms. These results suggest that the retention of a global percept is an emerging property of the ventral visual processing stream and the maintenance of grouped visual elements is independent of cue type. We postulated that perceptual persistence depends on a system of perceptual memory reflecting the state of perceptual organization.
Vulvovaginale Erkrankungen: Unterscheidung zwischen behandlungsfähigen Infektionen und anderen Ursachen
Authors: Petersen Eiko E.
Published: January 2005

Beschwerden im Vulvabereich sind häufig. Nur ein Teil der Entzündungen ist durch eine Infektion verursacht. Die Zahl der Erreger ist auf wenige begrenzt. Nichtinfektiöse entzündliche Dermatosen und Allergien kommen auch an der Vulva vor und sollten sehr viel mehr beachtet werden. Während Infektionen meist heilbar sind, lassen sich einige Dermatosen heilen, viele aber nur noch bessern. Der Stellenwert der Hautpflege wird noch zu wenig beachtet. Die frühzeitige Erkennung und Behandlung von entzündlichen Prozessen an der Vulva ersparen vielen Patientinnen unnötige Beschwerden und verhindern auch Vulvakarzinome bzw. allzu verstümmelnde Eingriffe.
Adnexitis und «Pelvic Inflammatory Disease»
Authors: Lauper U. , Schlatter C.
Published: January 2005

Unter PID («pelvic inflammatory disease») und Entzündungen des oberen Genitaltrakts («upper genital tract infections») verstehen wir entzündliche Veränderungen des oberen weiblichen Genitaltrakts jeglicher Kombination: Endometritis, Salpingitis, Tuboovarialabszess, Peritonitis im kleinen Becken. Die International Infectious Disease Society for Obstetrics and Gynecology empfiehlt eine Revision der CDC-Richtlinien mit Berücksichtigung des Erregers bzw. des verursachenden Agens und des Schweregrades der Erkrankung. Infektionen mit Chlamydia trachomatis und Neisseria gonorrhoeae sind weltweit am Zunehmen und gelten als eine der Hauptursachen von tubarer Sterilität, chronischen Unterbauchschmerzen und ektopen Schwangerschaften. Über 30% der Infektionen verlaufen subklinisch oder asymptomatisch. Deshalb sollte bei jungen, sexuell aktiven Frauen mit Risiken ein generelles Screening durchgeführt werden. Die antibiotische Therapie sollte möglichst früh, im Zweifelsfall probatorisch, begonnen werden und ein breites Keimspektrum abdecken. C. trachomatis und Gonokokken werden spezifisch und resistenzgerecht therapiert. Bei leichten Verläufen scheint die ambulante Therapie keine Nachteile gegenüber einer Hospitalisation zu haben.
Klinische Bedeutung der Antibiotikaresistenz in Gynäkologie und Geburtshilfe
Authors: Ruef Christian
Published: January 2005

Die Antibiotikaresistenz von Mikroorganismen, die für Infektionen des Urogenitaltraktes verantwortlich sind, ist ein klinisch relevantes Problem in der Gynäkologie und Geburtshilfe. Gleichzeitig wird die Resistenzprüfung aufgrund methodologischer Schwierigkeiten sehr selten eingesetzt, so dass genaue Angaben über die Epidemiologie der Antibiotikaresistenz bei den meisten Erregern fehlen. In verschiedenen Regionen scheint die Antibiotikaresistenz von Trichomonas vaginalis und Gardnerella vaginalis (Metronidazol), Streptococcus agalactiae (Makrolide, Clindamycin), Mycoplasma hominis (Tetracycline, bei vorbestehender intrinsischer Resistenz gegen Makrolide) zuzunehmen. Zusätzlich wurden Einzelfälle klinischer Infektionen durch multiresistente Chlamydia trachomatis berichtet. Das Vorliegen einer Antibiotikaresistenz sollte deshalb bei unbefriedigendem klinischem Verlauf in Betracht gezogen werden. Angesichts der zunehmenden Resistenzproblematik und der zum Teil grossen Wissenslücken sollten die Forschungsanstrengungen auf dem Gebiet der Antibiotikaresistenz bei gynäkologischen Infektionen intensiviert werden.
Sentinel-Lymphonodektomie – Der neue operative Standard für die Evaluation der Axilla: Ein Überblick
Authors: Rageth Christoph J. , Scholl Beatrix , Sarasin Eliane , Saurenmann Elisabeth
Published: January 2005

Die axilläre Lymphonodektomie ist immer noch integraler Bestandteil der Mammakarzinomtherapie, verursacht aber eine deutliche Morbidität. Die Sentinel-Lymphknotenoperation weist eine wesentlich geringere Morbidität auf und vermeidet bei gegebener Indikation zunehmend die komplette Axilladissektion. Die Sentinel-Lymphonodektomie hat sich als neuer operativer Standard etabliert und sollte allen Patientinnen mit unizentrischen Tumoren unter 3 cm Durchmesser angeboten werden. Die offenen Fragen betreffen vor allem den Injektionsort der Markersubstanz, die Bedeutung des Auffindens und Entfernens extra-axillärer Lymphknoten und die Anwendbarkeit der Methode bei multizentrischem Tumor, nach neoadjuvanter Chemotherapie, vorausgegangener Brustbiopsie, beim DCIS und bei Tumoren von mehr als 3 cm Grösse. Auch das Vorgehen nach Auffinden von Mikrometastasen ist noch Gegenstand wissenschaftlicher Studien.
Abort- und Frühgeburtenrate nach akuter Mumpsinfektionin der Schwangerschaft
Authors: Enders M. , Rist B. , Enders G.
Published: January 2005

Fragestellung: Aufgrund der hohen Durchseuchungsraten treten akute Mumpsinfektionen in der Schwangerschaft nur selten auf. Daher ist die Datenlage zu möglichen negativen Auswirkungen der Mumpsinfektion auf den Schwangerschaftsausgang begrenzt. Patientinnen und Methoden: In unserem Labor wurde zwischen Januar 1985 und Dezember 2002 bei 79 Schwangeren die klinische Diagnose einer Mumpsinfektion serologisch bestätigt. Die uns vorliegenden Daten zum Schwangerschaftsausgang wurden durch die behandelnden Gynäkologen oder Geburtshelfer im Rahmen der Diagnostik und Beratung übermittelt. Nabelschnurblutproben von 26 der 57 lebend geborenen Kinder wurden mittels Enzymimmunoassay auf das Vorliegen mumpsspezifischer IgM- und IgG-Antikörper untersucht. Ergebnisse: Zweiundsechzig Patientinnen wurden prospektiv bis zum Ende der Schwangerschaft verfolgt. In 2 Fällen erfolgte eine Interruptio aus sozialer Indikation. Die fetale Verlustrate betrug bezogen auf das Gesamtkollektiv 6,6% (4/60). Nur 2 Aborte traten im ersten Trimenon auf. Alle Aborte wurden jedoch bei Patientinnen beobachtet, die im ersten Trimenon an Mumps erkrankten. Ein konstantes Zeitintervall zwischen Mumpsinfektion und Schwangerschaftsverlust war nicht zu verzeichnen. Das mediane Gestationsalter lag zum Zeitpunkt der Entbindung bei 40 Schwangerschaftswochen (SSW). Zwei der 57 lebend geborenen Kinder (3,5%) wurden vor der vollendeten 37. SSW entbunden. In keiner der 26 untersuchten Nabelschnurblutproben waren mumpsspezifische IgM-Antikörper nachweisbar. Schlussfolgerungen: Der fehlende Nachweis mumpsspezifischer IgM-Antikörper im Nabelschnurblut spricht bei den untersuchten Fällen gegen eine pränatale Mumpsinfektion. Die beobachtete Frühgeburten- und Abortrate erscheint nach Mumpsinfektion in der Schwangerschaft im Vergleich zum Normalkollektiv nicht erhöht.
New Prospects for the Management of Renal Bone Disease
Authors: Steddon Simon J. , Fan Stanley L.S. , Cunningham John
Published: January 2005

The last decade has been a remarkably productive one in the field of bone biology. New insights into the maintenance of a normal bone microenvironment have led to significant advances in our understanding of many important skeletal disorders, including renal osteodystrophy. Novel targets for therapeutic manipulation have been exposed and encouraging progress made towards new treatments. In addition, just as clinical studies have alerted us to the potential hazards of vascular calcification, basic science has unearthed the intimate nature of the relationship between the previously separate disciplines of bone and vascular biology. The clinical nephrologist, however, may be forgiven a little cynicism at this point. If such progress has been made, why do the same proverbial difficulties confront us in day-to-day practice? Control of phosphate remains inadequate, despite a literature which constantly reaffirms its crucial importance, and parathyroid hyperplasia seems inevitable in many patients. Furthermore, even the satisfaction of successful control of serum parathyroid hormone concentration must now be tempered by disquiet regarding the skeletal and cardiovascular consequences of oversuppression. This review aims to provide an update of the latest developments in relevant skeletal research and to assess how recently acquired knowledge may improve clinical nephrological practice over the next five years.
In vivo Confocal Laser Scanning Microscopy and Micropuncture in Intact Rat
Authors: Ohno Yoshio , Birn Henrik , Christensen Erik I.
Published: January 2005

Background: Intravital microscopy theoretically provides the optimal conditions for studying specific organ functions. However, the application of microscopy in intact organs in vivo has been limited so far due to technical difficulties. The purpose of this study was to establish a method of in vivo confocal laser scanning microscopy (CLSM) for the study of endocytosis in proximal tubules of intact kidney. Methods: The left kidney of rats placed on a modified microscope stage was exposed and stabilized in a thermostatically controlled cup. The stage was then attached to an upright confocal microscope. Surface proximal tubules were microinfused with fluorescent albumin or transferrin. Single or time-series images of microinfused proximal tubules were recorded in reflection and/or fluorescence mode. Results: The stability of the kidney and the resolution of images were sufficient to visualize intracellular vesicles. Albumin and transferrin were initially observed at the brush border, then later internalized by proximal tubules and accumulated in lysosomes over a time period of 15 min. Furthermore, fusion of vesicles was observed in time-lapse images. Conclusion: These results show that in vivo CLSM in intact kidney may be an excellent method to evaluate proximal tubular endocytosis and ligand trafficking.
Aldosterone Rapidly Activates Na+/H+ Exchange in M-1 Cortical Collecting Duct Cells via a PKC-MAPK Pathway
Authors: Markos Farouk , Healy Vincent , Harvey Brian J.
Published: January 2005

Background: In this study, the mechanism of the rapid non-genomic effect of aldosterone on Na+/H+ exchanger (NHE)-mediated intracellular pH (pHi) recovery from an acid load in murine M-1 cortical collecting duct cells was assessed. Methods: Spectrofluorescence microscopy and Western blot analysis was carried out and NH4Cl was used to induce the acid load. Results: Aldosterone (10 nM) induced a rapid (<5 min) concentration-dependent increase in pHi recovery in M-1 cells, an effect mimicked by its precursor deoxycorticosterone (1 nM). This response was unaffected by the mineralocorticoid receptor (MR) antagonist spironolactone (10 µM) but was significantly reduced by the NHE antagonists 5′-(N-ethyl- N-isopropyl)amiloride (EIPA) (20 µM) and cariporide (1 µM). The PKC inhibitor chelerythrine chloride (1 µM) significantly attenuated the aldosterone-induced increase in NHE1 activity. HBDDE (80 µM), a PKCα inhibitor, inhibited the rapid aldosterone effect whereas rottlerin (15 µM), a PKCδ antagonist, did not. The glucocorticoid receptor agonists hydrocortisone (1 µM) and dexamethasone (100 nM) decreased NHE activity, whereas the synthetic mineralocorticoid fludrocortisone (1 nM) had no significant effect. MAPK inhibition using PD98059 (25 µM) significantly attenuated the rapid aldosterone effect; Western blot analysis showed that aldosterone activation of ERK 1/2 was unaffected by pretreatment with spironolactone but was inhibited following chelerythrine chloride. Conclusion: Aldosterone causes a rapid non-genomic increase in NHE1 activity in M-1 cells via a PKCα /MAPK pathway independent of the classical MR.
N-Acetylcysteine Ameliorates Amphotericin-Induced Nephropathy in Rats
Authors: Feldman Leonid , Efrati Shai , Dishy Victor , Katchko Leonid , Berman Sylvia , Averbukh Michael , Aladjem Mordechai , Averbukh Zhan , Weissgarten Joshua
Published: January 2005

Background: Amphotericin B may cause acute reduction in renal function. N-acetylcysteine (NAC) has a renoprotective activity in several nephrotoxic renal insults, but its effect on amphotericin-induced renal failure has not been investigated yet. Methods: Acute renal failure was induced in 30 Sprague-Dawley rats by a single intraperitoneal injection of amphotericin B (50 mg/kg). NAC (10 mg/kg) in isotonic saline or isotonic saline alone were administered daily for 4 days, starting 1 day before the amphotericin B injection. Glomerular filtration rate (GFR) was assessed using 99m-technetium diethylene triaminepentaacetic acid. Before and following amphotericin B administration, a 24-hour urine collection was performed for sodium, potassium and magnesium determination. The kidneys were preserved for pathologic examination. Results: Amphotericin B induced a significant decrease of GFR in both groups. Four days after amphotericin injection the GFR in the NAC-treated group was significantly higher than in the control group (0.62 ± 0.20 vs. 0.46 ± 0.14 ml/min, p = 0.042). Histologic signs of acute tubular necrosis were attenuated in the NAC-treated group. There were no significant differences between the groups in sodium, potassium and magnesium urine excretion after amphotericin injection. Conclusions: NAC treatment exerted a renoprotective effect on deterioration of GFR in a rat model of amphotericin-induced renal failure. No functional protection on tubular function, as obviated by similar polyuria and urine losses of potassium and magnesium in both groups, was observed.
Clinical Results of Daily Hemofiltration
Authors: Kawanishi Hideki
Published: January 2005

Various types of daily hemodialysis (HD) have been developed. However, a water treatment system is essential for HD, which markedly prevents daily home HD. Hemofiltration (HF) can be simply performed only with substitution fluid without a water treatment system. This advantage is applied to daily HF. To perform this procedure at home, a simple system is needed. A system in which a dialyzer was combined with a circuit as one cartridge with bag-type substitution fluid was developed by NxStage Inc. This system facilitates not only HF via a supply of 15 l of bag-type substitution fluid, but also automatic washing/priming of the circuit and returning which can be achieved by applying the current CAPD management system. This daily HF may contribute to routine home HD in the future.
Kinetics and Dose of Daily Hemofiltration
Authors: Yamashita Akihiro C. , Kawanishi Hideki
Published: January 2005

Daily hemofiltration (D-HF) is a new treatment modality that shows unique solute removal characteristics and possibly provides high quality of life for patients with end-stage renal disease. We evaluated solute removal characteristics of D-HF for 5 patients by kinetic modeling analysis. Five patients treated with normal 4-hour × 3 times/week hemodialysis (HD) were switched to D-HF (2-hour × 6 times/week). Ultrafiltration rates (QF) or small solute clearances ranged from 63 to 106 ml/min. All the pertinent kinetic parameters were determined from patients’ physical data and the HD portion of the clinical measurements. The two-compartment kinetic model predicted the concentration changes after switching from normal HD to D-HF. In all 5 patients, concentrations of small solutes such as urea-nitrogen (UN) increased whereas that of β2-microglobulin (β2-MG) decreased after switching from normal HD to D-HF. Predicted solute concentrations and clinical measurements for UN and β2-MG were in good agreement with average error less than 10%. The model predicted that QF = 155 ml/min may be necessary for the time-averaged concentration (TAC) of UN to be unchanged. The model also predicted that the 7 times/week D-HF should not increase the pretreatment concentration of UN, expecting even much lower β2-MG concentration after switching from normal HD to D-HF. D-HF is superior to normal HD for removing larger solutes but may increase the TAC of small solutes. A 7-day treatment (7 times/week) D-HF may improve the solute removal capacity of small solutes.
Ultrapure Dialysis Fluid – Direct and Indirect Benefits in Dialysis Therapy
Authors: Ledebo Ingrid
Published: January 2005

The fluid quality description ‘ultrapure’ means practically free from bacteria and endotoxin. In quantitative terms it is defined as <0.1 CFU/ml and <0.03 EU/ml. The requirements on endotoxin as well as bacteria should be fulfilled, because these two entities are not strictly correlated. Ultrapure dialysis fluid can be prepared from standard quality fluid by a single step of controlled ultrafiltration. Recent clinical studies demonstrate that the use of ultrapure dialysis fluid in hemodialysis is associated with patient benefits indicating a less inflammatory state compared to hemodialysis with standard fluid. By applying one additional step of controlled ultrafiltration, ultrapure dialysis fluid can be further purified to such high microbiological quality that it can be used for infusion. This opens up the possibility for convective therapies, hemodiafiltration and hemofiltration, for which large volumes of sterile infusion solution are needed. With optimal application of these therapies, solute removal is enhanced, qualitatively as well as quantitatively, and fluid management is facilitated through improved hemodynamic stability.
Use of Ultrapure Dialysate in Reduction of Chronic Inflammation during Hemodialysis
Authors: Arizono Kenji , Nomura Kazufumi , Motoyama Takeshi , Matsushita Yoshio , Matsuoka Kiyoshi , Miyazu Rikako , Takeshita Hisako , Fukui Hiroyoshi
Published: January 2005

Chronic inflammation contributes to the pathogenesis of several complications of hemodialysis therapy. It is thought that backfiltration of bacteria-derived contaminations during dialysis may induce a chronic inflammatory state. High-sensitivity C-reactive protein (hs-CRP) is one of the tools which can take a hold on such a chronic inflammatory condition. We examined the effect of ultrapure dialysate which contributes to chronic inflammation with hs-CRP and tried to reduce endotoxin (ET) levels at the end of the dialysate from 70 EU/l to <1.0 EU/l (ultrapure dialysate). Other dialysis conditions, except ET level, were fixed. We investigated the hs-CRP of 23 patients receiving regular dialysis before the use of ultrapure dialysate and 1 year after use of it prospectively. The data showed a significant decrease in the median value of the hs-CRP from 0.16 to 0.07 mg/dl (p < 0.05). The value of serum β2-microglobulin decreased from 33.2 to 28.4 mg/dl (p < 0.01) and the hemoglobin level increased from 10.0 to 11.0 g/dl (p < 0.05). These results indicate that even a dialysate containing 70 EU/l of ET level may induce a chronic inflammatory state. hs-CRP is a very useful marker of chronic inflammation and the use of ultrapure dialysate is necessary to improve a chronic inflammatory state. The targeted ET level at the end of the dialysate should be set at ≤1.0 EU/l.
Complementary Dialysis for Daily Dialysis
Authors: Kawanishi Hideki
Published: January 2005

The greatest benefit of PD ist the continuous maintenance of a stable electrolyte and acid-base balance, as well as a continuous solute, sodium and water removal. Moreover, PD is effective in preserving residual renal function (RRF). However, when RRF declines, complications will occur if not compensated for by an increase in both the dialysis dose and ultrafiltration. Combination therapy PD and HD has been implemented to address the weakness of PD. The weak points of PD are declining UF volume and solute removal over time. The most important weak point of HD is the intermittent nature of the treatment. Based on this, the following concept was developed. At the start of dialysis, PD should be initiated in order to maintain RRF. In this stage, the function of PD is a complement to the RRF. When RRF declines, combination PD and HD should be considered. Subsequently, to achieve sufficient solute removal and ultrafiltration, the number of HD sessions should increase and PD prescription may decrease, resulting in three HD sessions per week and low-volume PD on non-HD days. Thus, PD complements HD in the end. If this integration can become a reality, we can accomplish ‘real’ daily dialysis.
Internal Filtration-Enhanced Hemodialysis Is a Cost-Effective Treatment in View of Solute Removal
Authors: Koda Yutaka
Published: January 2005

By modifying dialyzer module design, internal filtration (IF) within a dialyzer is enhanced to increase convective solute transport. Thus, it can be an alternative to hemodiafiltration with no requirement of substitution fluid or additional complex machines. Cost-effective analysis was conducted in three modes of therapy: high-flux hemodialysis, on-line hemodiafiltration and IF-enhanced hemodialysis. In IF-enhanced hemodialysis, cost-effectiveness of small solute removal is comparable with high-flux hemodialysis and that of β2-microglobulin removal is the best. It is concluded that IF-enhanced hemodialysis is the most cost-effective therapy mode in comprehensive overall solute removal.
‘Clean Dialysate’ Requires Not Only Lower Levels of Endotoxin but Also Sterility of Dilution Water
Authors: Shinoda Toshio
Published: January 2005

Clean dialysate should be used in dialysis with a high-flux dialysis membrane to avoid contamination of endotoxin into blood circuits. For this purpose, we should not only clean up the end stream dialysate by endotoxin-cut filters, but also prevent bacterial growth in dilution water lines. Delivery lines of the prepared dialysate from a central dialysate-supplying machine are sterilized in all dialysis facilities, but those of the dilution water in cases of using personal dialysis machines are not sterilized in most facilities in Japan. In our dialysis department, the endotoxin level in the dilution water lines decreased to <50 EU/l in 3 weeks by sterilization with a low concentration of sodium hypochlorite (30–100 ppm) once a week from the peak level of >1,000 EU/l just after the start of sterilization.