bluuebunny/crossref_metadata_2025 huggingface dataset:
Über die Wirtschaftlichkeit verschiedener Verfahren zur Entwässerung von biologischem Klärschlamm
Authors: Lohmann Jörg
Published: May 2005

Die Entwässerung biologischer Klärschlämme kann in mehreren Stufen und durch verschiedene Vorrichtungen erfolgen, die sich in Kosten‐ und Betriebsverhalten unterscheiden. Anhand von Versuchsergebnissen sowie Investitions‐ und Betriebskosten wird der Einfluß des Flockungsmittels‐ bzw. Filterhilfsmittel‐Verbrauches auf die Entwässerungskosten am Beispiel des Vakuumfilters, der Bandpresse und der Zentrifuge bei nachfolgender Verbrennung diskutiert. Die Kosten werden durch die Schlammzusammensetzung und ‐menge sowie die örtlichen Deponiemöglichkeiten wesentlich beeinflußt. Durch Auswahl geeigneter Verfahrenskombinationen, Entwässerungsvorrichtungen und Wahl günstiger Betriebseinstellungen lassen sich die Aufbereitungskosten vermindern. Wie weit eine Verringerung des Deponievolumens durch Verbrennung wirtschaftlich ist, wird wesentlich durch die Energiekosten und den organischen Gehalt der Schlämme bestimmt.
Auslegung moderner Tieftemperatur‐Anlagen zur Gewinnung von Sauerstoff, Stickstoff und Edelgasen
Authors: Springmann Helmut
Published: May 2005

Nach einigen grundsätzlichen Bemerkungen zu Luftzerlegungsverfahren werden Auslegungsprobleme an einzelnen Anlagentypen erläutert. Besonders ausführlich wird der Anlagentyp zur Gewinnung von reinem gasförmigen Sauerstoff geschildert. Am Beispiel von Anlagen zur Gewinnung von Sauerstoff für Vergasungszwecke werden einige Bemerkungen zu Großluftzerlegern gemacht. Rektifikationsprobleme werden an Hand der Anlagen zur Gewinnung von reinen Produkten untersucht. Adsorptions‐ anlagen werden zur Gewinnung von Sauerstoff mittlerer Reinheit empfohlen. Ein Vergleich verschiedener Methoden zur Erzeugung von Schutzgas wird angestellt, und abschließend werden Automatisierungsprobleme erörtert.
Vorschriften für die Genehmigung von Anlagen nach dem Bundesimmissionsschutzgesetz
Authors: Kremer Gottfried
Published: May 2005

Der Aufsatz behandelt den beim Bau und Betrieb von verfahrenstechnischen Anlagen heute besonders aktuellen Gesichtspunkt des Umweltschutzes. Der Gesetzgeber hat im Bundesimmissionsschutzgesetz die Voraussetzungen angegeben, unter denen Anlagen errichtet und betrieben werden dürfen. Über die Erfahrungen, die in den ersten beiden Jahren mit diesem Gesetz und den Technischen Anleitungen zur Reinhaltung der Luft und zum Schutz gegen Lärm gemacht wurden, wird berichtet und auf notwendige Verbesserungen der Genehmigungspraxis eingegangen.
Neue Anwendungen der Flüssigmetall‐Technologie für Stoffumwandlungs‐ und Veredelungsprozesse
Authors: Klapp Eberhard Ulrich
Published: May 2005

Neue Technologien verlangen zunehmend nach kompakten Wärmeübertragungssystemen, die hohe Wärmeleistungen bei kleinem Gewicht und kleinem umbautem Raum zu übertragen gestatten. Entsprechende Bemühungen gelten insbesondere Gasphaseapparaten. Die Eignung von flüssigem Metall für diese Zwecke ist unbestritten. Mittels flüssiger Metalle als Wärmezwischenträger kann Hochtemperaturwärme sowohl in offenen als geschlossenen Systemen ein‐ und ausgekoppelt werden. Aus Sicherheits‐ und Inspektionsgründen finden sich in der Kernreaktortechnik allein geschlossene Systeme in der Entwicklung. Die wirtschaftlichen Nachteile der die flüssigen Metalle kennzeichnenden hohen Pumpleistung legen es nahe, mit stagnierenden Metallschmelzen zu arbeiten, in die die Wärme durch Eindüsen des Heißgases als disperse (diskontinuierliche) Phase eingebracht wird. Trennwände erübrigen sich in diesem Fall, entsprechende Systeme werden als „offen”︁ bezeichnet und sind dem Bereich der Direktwärmeübertragung zuzuordnen. Anwendungsbeispiele für offene Systeme werden gegeben (Bleibad‐Wärmeübertrager, Oberflächenbehandlung metallischer Werkstoffe). Die Einsatzmöglichkeiten disperser Systeme vom Typ Gas/Flüssigmetall für neue Technologien einschließlich Vergasungstechniken werden überprüft und hinsichtlich ihrer Schaltungsmöglichkeiten beurteilt.
Hochleistungsverfahren für die Trinkwasser‐Aufbereitung
Authors: Haberer Klaus
Published: May 2005

Neuere Verfahrensentwicklungen auf verschiedenen Gebieten der Trinkwasser‐Aufbereitung, nämlich Schnell‐ und Langsamfiltration, Belüflung, Entsäuerung und Teilentcarbonisierung sowie Flockung und Sedimentation, gestatten gegenüber den „konventionellen”︁ Verfahren wesentlich — meist um den Faktor 2 bis 3 — höhere Durchsätze. Der Vorteil der neuen Prozeßführungen liegt in der kompakteren Bauweise mit bedeutend verringertem Platzbedarf und in der Möglichkeit, die Leistung bestehender Wasserwerke allein durch Umrüsten vorhandener Anlagen, also ohne größeren Bauaufwand und ohne Flächenausdehnung, dem zunehmenden Wasserbedarf anzupassen.
Process design with energy and environmental constraints
Authors: Timmerhaus Klaus D. , Reusch Charles F.
Published: May 2005

It is evident that the philosophy of process design has changed dramatically with the advent of higher energy prices and stricter environmental regulations. It is only with careful design and well‐practiced operation that maximum recovery of energy in the form of steam, electricity and refrigeration can be successfully achieved. Initial capital costs will generally be higher, but operating costs are lower, particularly in this era of high fuel costs. The major problems that are usually associated with these „tighter”︁ designs are more difficult maintenance and more complex startup problems. The latter are due to the energy integration which is built into an energy efficient plant. On the other hand, maximizing energy recovery and increasing yields of feedstocks not only lowers operating costs but often can have environmental advantages because exhaust gases and liquids are either consumed in the plant or contaminants are recovered as byproducts.
Verfahren zum Trennen von dispersen Feststoffgemengen in ihre stofflichen Komponenten
Authors: Kellerwessel Hans
Published: May 2005

Verfahren zum Trennen von dispersen Feststoffgemengen nach stofflichen Eigenschaften – Sortierverfahren – erlangen zunehmend Bedeutung auch außerhalb ihrer klassischen Anwendungsgebiete, nämlich der Aufbereitung mineralischer Rohstoffe und landwirtschaftlicher Produkte. Dies gab Veranlassung zu einer Zusammenstellung, in der die Grundlagen der wichtigsten Sortierverfahren und ihre Anwendungsmöglichkeiten außerhalb der klassischen Bereiche aufgezeigt werden.
Längsmischung in gerührten Gegenstrom‐Extraktoren
Authors: Marr Rolf , Moser Franz , Husung Gerrit
Published: May 2005

Es wurden die Methoden zur Erfassung der Längsmischung in gerührten Extraktoren behandelt. Dabei ergab sich, daß lediglich die einphasigen Vermischungszustände der kontinuierlichen Phase gut bestimmbar sind; mit gewissen Einschränkungen gilt das auch für die disperse Phase. Vor allem für RDC und ARD liegen Korrelationen vor, die die Berechnung von Bodenstein‐Zahlen der kontinuierlichen Phase bis zu 4 m Kolonnen‐Dmr. zulassen. Beim Kühni‐Extraktor dagegen ist von derartigen Hochrechnungen bei Maßstabsvergrößerungen noch abzuraten. Es wird ein Weg zur Ermittlung rückvermischungsfreier HTU‐Werte erläutert, der die Übertragung auf Großkolonnen erlaubt. Es ist daher von großer Bedeutung, ausreichend gute Korrelationen zur Berechnung der Vermischung der dispersen Phase zu finden, um im Zusammenhang mit denen der kontinuierlichen Phase möglichst exakte Dispersionshöhen zu erhalten. Diese sind von der Geometrie und den Betriebsvariablen abhängig und sollten daher auch bei großen Kolonnen bestimmt werden. Damit wäre eine gute Möglichkeit gegeben, Kolonnenhöhen nach diesem Konzept zu berechnen.
Blasensäulen‐Reaktoren – ihre modellmäßige Erfassung und Berechnung
Authors: Deckwer Wolf‐Dieter
Published: May 2005

Die Dimensionierung und Maßstabsvergößerung von Blasensäulen‐Reaktoren ist trotz ihrer einfachen Bauweise eine recht schwierige Aufgabe. Es sind im wesentlichen zwei Punkte, die die „a priori”︁ ‐Berechnung erschweren und die nicht unabhängig voneinander betrachtet werden dürfen. Der 1. Punkt betrifft die Besorgung von Parameterwerten, der 2. Punkt liegt in der Auswahl realistischer Modelle. Aus dem Verweilzeitverhalten der Phasen ergibt sich, daß Modelle für Blasensäulen auf der Basis des Dispersionsmodells bzw. dazu äquivalenter Zellenmodelle zu erstellen sind. Zusätzlich liegt ein Druckgradient vor. Wenn deutliche Molstromänderungen in der Gasphase auftreten, wie es für die Praxis wünschenswert ist, ist ferner zu berücksichtigen, daß die Gasgeschwindigkeit und die relativen Phasenanteile variabel sind. Diese Modellannahmen führen auf ein nichtlineares Differentialgleichungssystem mit Randwerten, das nach verschiedenen Methoden numerisch gelöst werden kann. Aus Modellsimulationen wird der Einfluß der verschiedenen Parameter und Betriebsbedingungen ersichtlich. Experimentelle Untersuchungen zur mit Schwefelsäure katalysierten Hydratation von Isobuten und zum Stoffaustausch von CO2 in Blasensäulen bis zu 7 m Höhe bestätigen die Modellvorstellungen. Die experimentellen und theoretischen Ergebnisse werden mit Aussagen einfacherer Modelle verglichen und die Bedingungen angegeben, bei denen ihre Anwendung zu rechtfertigen ist.
Ultrafiltration und Umkehrosmose Grundlagen und Technologie
Authors: Rautenbach Robert , Rauch Klaus
Published: May 2005

Zur Beschreibung des Stofftransportes in technischen Membranen sind mehrere Modellvorstellungen entwickelt worden. Ausgehend von einer Diskussion dieser Vorstellungen wird gezeigt, wie Anlagen für Membrantrennprozesse ausgelegt werden können. Die Arbeit beschränkt sich dabei auf die technisch z. Z. meist diskutierten Membrantrennverfahren „Ultrafiltration”︁ und „Umkehrosmose”︁, bei denen die Abtrennung einer Komponente aus einer meist wäßrigen Lösung aufgrund einer transmembranen Druckdifferenz erfolgt. Für die Auslegung ist neben dem Transport in der Membran selbst der Stofftransport aus der zu trennenden Lösung an die Membranoberfläche von Bedeutung. Es wird gezeigt, daß zur Beschreibung dieser Vorgänge bekannte Gleichungen für den Wärmetransport herangezogen werden können, daß aber im Gegensatz zu einer Wärmeaustauscher‐Berechnung das Gleichungssystem zur Berechnung der Flüsse und Konzentrationen an angeströmten Membranen nur iterativ gelöst werden kann. Die wichtigsten Membrankonfigurationen (Rohr‐, Platten‐, Hohlfaser‐ und Wickelmodul) werden besprochen und Gleichungen zur Beschreibung ihrer Austauschcharakteristik angegeben.
Kostenvorausberechnung von Apparaten und Anlagen — Möglichkeiten und Grenzen
Authors: Schwind Hermann
Published: May 2005

Costing of equipment and plants – possibilities and limitations. The costing of individual items of equipment and of complete plants differs considerably with respect to design as well as to the accuracy and time‐requirement of the calculation method. These calculations are included in the usual way in economic evaluations of plants in order to assess the overall profit situation of a plant project. Numerous publications on this subject have appeared in recent years. They are evaluated in this report with reference to the abovementioned aspects. Besides the cost‐precalculation methods used in project engineering, a few systematic costing methods are proposed for the planning‐, erecting‐ and operating‐period of a plant. This facet of the subject is also critically examined.
Blasensäulen‐Reaktoren
Authors: Gerstenberg Helmut
Published: May 2005

Bubble column reactors.Bubble columns and their state of development have been reviewed on numerous occasions in recent years. As an extension, this paper deals with bubble column reactors from an industrial point of view. The numerous forms of construction and modes of operation in industry can be reduced to relatively few fundamental types. Since the computerized design of bubble columns is presently restricted to a few partial processes, experience in the choice of a particular type column still plays an important role. The article deals, inter alia, with reactors (gas distribution, gas‐ and liquid‐feeds, gas separation, heat extraction), selection criteria for construction and for operating conditions, practical experience, and some specific forms of operation. Some problems still requiring scientific investigation are outlined.
PROBAD – Programmsystem zur Festigkeitsberechnung von Behältern, Apparaten und Dampf‐Erzeugern
Authors: Schmidt‐Traub Henner
Published: May 2005

PROBAD – A program system for stress calculations on vessels, equipment, and steam generators. The PROBAD program system performs stress calculations according to TRD Rules, AD Codes, DIN Standards, as well as ASME Code Sec. VIII Div. 1 and TEMA Standards. Starting from given assemblies, whole vessels or parts thereof are designed or checked. Moreover, the PROBAD language also permits supplementary assignment of user‐specific and standard values to the system without any need for direct modification of the program system. The input and output can likewise be set up in a user‐specific manner.
Titancarbid – Ein technischer Hartstoff
Authors: Binder Franz
Published: May 2005

Titanium carbide – an industrial hard material. Titanium carbide, whose industrial application has been closely linked with the history and development of sintered metal carbides since 1930/31, has revolutionized the technology of the machining of steel when used in the form of multicarbide composites. Typical innovations of the post‐war era are not only the dominant WC/TaC/TiC‐Co carbide materials but also TiC‐NiMo materials and TiC‐coated metal cutting devices. In contrast to TaC or WC, the market situation is largely independent of price and quantity fluctuations of raw materials.
Zusätzliche Sicherheitsaspekte des Mehrlagenbehälters
Authors: Opitz K. , Beser A. E.
Published: May 2005

Additional safety aspects of coiled‐layer containers. The coiled‐layer construction technique has a number of particular safety engineering advantages over solid construction methods which are characterized by the following features: (1) Each kind of stress in a container is directed to a shell specially designed for this kind of stress. (2) A planned arrangement of welding seams minimises weakening. (3) The containers can be constantly monitored. (4) Failures remain under control owing to the possibility of constant monitoring. Examples and experiments are reported for the Krupp coiled‐layer construction method.
Automatisierte Überwachung der Luftverschmutzung
Authors: Mögele Ludwig , Birkle Michael
Published: May 2005

Automated monitoring of atmospheric pollution. More and more fully‐automated, computer‐controlled measuring grids for the monitoring of immission or nuisance levels are being planned and implemented. The requirements and limiting conditions in immission surveillance lead to hierarchically organized measuring systems in which the analytical apparatus are combined in automated monitoring stations. The monitoring stations each contain apparatus for the various pollutants as well as ancillary equipment. Great importance is attached to the sampling system and to equipment for automatic instrument surveillance.
Technische Prototypen für die Altreifen‐und Kunststoff‐Pyrolyse
Authors: Kaminsky Walter , Sinn Hansjörg , Janning Jörg
Published: May 2005

Industrial prototypes for the pyrolysis of used tyres and waste plastic materials. The increasing amounts of old tyres and waste plastics are creating problems regarding their disposal and recycling. Such wastes, however, can be converted by pyrolysis into almost residue‐free organic raw materials. Various processes, particularly for the pyrolysis of old tyres, are described which have been tested in Japan, the USA, Great Britain and the Federal Republic of Germany. In indirectly heated fluidized sand beds whole automobile tyres can be decomposed to give up to 20 wt‐% gas, 30 wt‐% aromatics, 40 wt‐% carbon black, and 10 wt‐% steel scrap.
Zum Stand der Berechnung von Behälterabstützungen und Fußkonstruktionen
Authors: Depmeier Lüder , Lambrecht Diethelm
Published: May 2005

Calculation of vessel supports and foot constructions. Supports of vessels often cause large strains in the wall of the container; generally the calculation of the resulting deformations and stresses turns out to be difficult. Several types of construction and the problems associated with local loadings are described, and possible methods of calculation are listed. Generally known publications are compared. Methods of series expansion are considered in more detail and their advantages as well as their limitations are shown for the example of a Fourier series expansion for a cylindrical tank. In addition two examples are considered which permit comparisons between our own calculations and usual methods and experimental results, respectively.
Energiewirtschaftliche Rationalisierung bei der Projektierung von Chemieanlagen
Authors: Schulze Joachim
Published: May 2005

Reduction of energy costs in planning of chemical plant. Energy consumption in the chemical industry is especially high, and on inclusion of energy sources used as raw materials the energy consumption figures are even doubled. The most important energy consumption data are presented. The economic incentives for the reduction of energy costs have increased with energy price hikes, and project engineering of new chemical plants offers an extensive field for energy saving measures. An account of the basic methods of economic optimisation of chemical plant equipment, with particular regard to the reduction of energy consumption, is followed by a systematic review of the various sectors of chemical plant design in which energy saving measures can be applied.
Entwicklungstendenzen bei Einschneckenextrudern
Authors: Fritz Hans‐Gerhard
Published: May 2005

Developments in single worm extruders. Starting from the multifarious chemical engineering tasks to be mastered in production and processing of plastics, the single worm extruders nowadays used for this task (plastifying extruders, melt‐exit extruders, degassing extruders, and cascade systems) are presented and the associated foci of development are mentioned. It becomes clear that further reductions in the price/performance relation of such plant will most likely be accomplished by a systematic analytical description of the mechanical/thermal unit process of conveying of solids in the individual functional zones, of plastifying, mixing, and homogenization, and pressure build‐up. The knowledge accruing from such model considerations leads to extruder sections which are optimized energetically and engineeringwise (grooved entry, intensive heat‐up, exit zones) which in turn satisfy requirements for higher mass throughputs and improved product quality. Similar analyses of the extruder/tool combined system can serve as a basis for process models for fully automated operation of extruders by means of microcomputer systems so far used to control individual operating parameters and acquisition of operating data.
Zur Maßstabsübertragung beim Suspendieren im Rührgefäß
Authors: Kneule Friedrich
Published: May 2005

Scale‐up of agitated vessels in the case of suspensions. In the scale‐up of agitated vessels a decrease of specific power input ε is recommended in the case of suspensions. Up to now it has been assumed that turbulence is the reason for this decrease. This paper shows that there may also be a contribution due to decreasing wall areas causing less wall shear stresses and moreover a reduction of circulation due to lower cross‐sectional areas per unit volume of the threads of flow. In the case of so‐called „complete suspension”︁ according to the „1‐s criterion”︁, two mechanisms can be distinguished: On the one hand we have a lifting of solid particles without, and on the other hand such a lifting with formation of bulk accumulations of solids on the bottom of the vessel. In the first case, scale‐up can be done as for a homogeneous distribution of the solid material. The specific power input ε is ∼ μ0 up to ε ∼ μ−1 with the scale‐up factor μ. In the second case (formation of dense solids clouds) a relationship ε ∼ μm with m > 0 was found.
Umweltfreundlichere Produktionsverfahren in der chemischen Industrie
Authors: Swodenk Wolfgang
Published: May 2005

Environmentally more acceptable processes in the chemical industrys. From its very beginning the chemical industry has always made every effort to cut the consumption of raw materials and energy in its processes and to diminish the release of by‐products and waste streams into the environment. These efforts at technically improving the various processes are presently being intensified by economical and political pressures of rising raw material costs and the rising costs of releasing harmful substances into the environment. Ways of reducing these influences on the environment by chemical processes and of improving process economics will be reported from the experience of Bayer AG. The examples show that it is possible to combine the indispensable with the practicable, and that in this way the burden on the environment can be kept as low as may be consistent with the image of the industrial society.
Technik der anaeroben Abwasserreinigung
Authors: Heijnen Joseph Johannes
Published: May 2005

Anaerobic waste water treatment. This article surveys the development of a high‐performance anaerobic reactor by overcoming biological and technological limitations. These limitations are discussed for various reactor types. The most suitable basis for a high‐performance reactor is provided by the anaerobic fluidized bed process.
Investitionskosten‐Schätzung für Chemieanlagen
Authors: Prinzing Peter , Rödl Roland , Aichert Dieter
Published: May 2005

Capital cost estimation for chemical plant. During the preliminary stages of an investment project (before approval), several decisions have to be made on whether or not it should be pursued. Therefore cost estimates are required with stepwise reduction in uncertainty. However, the attainable accuracy of a cost estimate is a function of progress in engineering the entire project. Thus, each step in cost estimation entails a higher degree of planning and demands methods that satisfy the accuracy demanded and correspond to the progress made in engineering. A comprehensive estimation system has been developed from these interrelations, and the respective procedures are described. This paper considers known fundamentals and the authors' own developments.
Der Wärmetransformator – Grundlagen und Anwendungen
Authors: Stephan Karl
Published: May 2005

Heat transformers – principles and applications. Heat transformers can transform low temperature waste heat into useful heat of higher temperature. They work by a sorption process and require little mechanical energy. This paper reviews the fundamentals, development trends, possible applications, and reports the efficiencies that can be expected when using different working substances. The economy of the process depends strongly on the credit for the useful heat. Some heat transformers are already in operation and deliver useful heat in the range of 1 to 10 MW.
Vakuumpumpen in der Verfahrenstechnik
Authors: Teifke Jürgen , Bohnet Matthias
Published: May 2005

Vacuum pumps in chemical engineering. Applications of vacuum pumps in chemical engineering are numerous. After a general systematization of the working principles of vacuum pumps, the most important types – liquid ring vacuum pumps, sliding vane vacuum pumps, and ejectors – are discussed with regard to their development and their working principle. Attention is focussed on aspects which allow a comparison of the advantages and disadvantages of vacuum pumps. A systematic survey of the criteria leading to the selection of a certain type of pump show that these criteria may be based on the process as a whole or on environmental and safety considerations as well as economic aspects. In areas where liquid ring vacuum pumps, sliding vane vacuum pumps, and ejectors may be applied the extent to which the pumps fulfill these criteria is shown. In this context, a comparison of the liquid ring pump and the sliding vane pump is of special interest. The doubts recently publicized concerning the environmental compatibility of liquid ring vacuum pumps are shown to be groundless if the pumps are installed correctly. Great care must be taken comparing the economic aspects of liquid ring pumps and sliding vane pumps.
Elektromembranverfahren. Teil 2: Anwendungsbeispiele
Authors: Kuppinger Franz‐Felix , Neubrand Wolfgang , Rapp Hans‐Jürgen , Eigenberger Gerhart
Published: May 2005

Electromembrane Processes, Part 2: Applications. The first part of this survey described the fundamentals and the basic equations for the mathematical modelling of electromembrane processes. In the second part a number of applications is considered. First mass transfer in ion exchange membranes is discussed. Further points are electrodialysis with bipolar membranes for the production of acid and base from a salt solution and some recent developments for the combination of electrodialysis and ion exchange.

Electrodialyse with bipolar membranes allows the recycling of acids or bases from acid or base scrubbersand can also be used for electrochemical reactions in nonaqueous media. Combination of electrodialysis and ion exchange permits a continous operation of ion exchange columns with simultaneous regeneration using ion exchange membranes. This results in low consumption of regeneration chemicals and the minimisation of waste products.
Hydrodynamischer Ansatz zur Modellierung von Fällungen
Authors: Franke Dirk , Gösele Walter
Published: May 2005

Modeling Precipitation with a Hydrodynamic Approach Particle sizes produced by precipitation are of prime importance for subsequent process steps, and they depend on mechanisms hardly understood until now. In this paper a new approach to the understanding of particle formation by precipitation is given. The solid is formed in the microscopic „Kolmogorov vortices”︁ where molecular mixing occurs. Loose aggregates within the vortex are cemented together by newly formed solid, the maximal size of the resulting solid aggregates being limited by the size of the vortex. Numerical calculation of the number of aggregates within the vortices and of the resulting aggregate sizes is performed, using one constant arbitrary fitting parameter. The agreement with experimental results is good. Further improvements of the model will require a better description of local fluid dynamics („mesomixing”︁).
Nitric oxide/cyclic guanosine monophosphate signaling in the central complex of the grasshopper brain inhibits singing behavior
Authors: Wenzel Beate , Kunst Michael , Günther Cornelia , Ganter Geoffrey K. , Lakes‐Harlan Reinhard , Elsner Norbert , Heinrich Ralf
Published: May 2005

Grasshopper sound production, in the context of mate finding, courtship, and rivalry, is controlled by the central body complex in the protocerebrum. Stimulation of muscarinic acetylcholine receptors in the central complex has been demonstrated to stimulate specific singing in various grasshoppers including the species Chorthippus biguttulus. Sound production elicited by stimulation of muscarinic acetylcholine receptors in the central complex is inhibited by co‐applications of various drugs activating the nitric oxide/cyclic guanosine monophosphate (cGMP) signaling pathway. The nitric oxide‐donor sodium nitroprusside caused a reversible suppression of muscarine‐stimulated sound production that could be blocked by 1H‐[1,2,4]oxadiazolo‐[4,3‐a]quinoxaline‐1‐one (ODQ), which prevents the formation of cGMP by specifically inhibiting soluble guanylyl cyclase. Furthermore, injections of both the membrane‐permeable cGMP analog 8‐Br‐cGMP and the specific inhibitor of the cGMP‐degrading phosphodiesterase Zaprinast reversibly inhibited singing. To identify putative sources of nitric oxide, brains of Ch. biguttulus were subjected to both nitric oxide synthase immunocytochemistry and NADPH‐diaphorase staining. Among other areas known to express nitric oxide synthase, both procedures consistently labeled peripheral layers in the upper division of the central body complex, suggesting that neurons supplying this neuropil contain nitric oxide synthase and may generate nitric oxide upon activation. Exposure of dissected brains to nitric oxide and 3‐(5′hydroxymethyl‐2′‐furyl)‐1‐benzyl indazole (YC‐1) induced cGMP‐associated immunoreactivity in both the upper and lower division. Therefore, both the morphological and pharmacological data presented in this study strongly suggest a contribution of the nitric oxide/cGMP signaling pathway to the central control of grasshopper sound production. J. Comp. Neurol. 488:129–139, 2005. © 2005 Wiley‐Liss, Inc.
Mice doubly affected by “staggerer” and “weaver” conditions
Authors: Yoon Chai H. , Frouhar Zohreh R.
Published: May 2005

In order to study the mode of interaction in mice of mutant genes that affect the motor activities and cerebellar cytoarchitectonics, double mutants affected by both the “staggerer” and “weaver” conditions were produced. The cerebellum of the double mutant mouse showed features present in both of the two single mutant cerebella. As to the features that were common to both single mutant cerebella, they were either more accentuated or similar to those found in one of the two single mutants which showed the greater change, with the possible exception of cerebellar fissures.
Retinal structure in the smooth dogfish Mustelus canis: electron microscopy of serially sectioned bipolar cell synaptic terminals
Authors: Witkovsky Paul , Stell W. K.
Published: May 2005

Portions of axons of bipolar cells in the retina of the smooth dogfish Mustelus canis were sectioned serially and examined by electron microscopy. The studied axons generally could be related to a bipolar cell sub‐type identified by light microscopy. Bipolar cell axons make ribbon synapses onto amacrine processes and ganglion cell dendrites, and onto ganglion cell perikarya. Bipolar cell ribbon synaptic complexes varied as to the number of post‐synaptic processes (1–3) and the orientation of the ribbon with respect to the post‐synaptic membrane. Amacrine processes made numerous conventional synapses onto bipolar cell axons, but reciprocal synapses between amacrine and bipolar cells constituted only 3–25% of all synapses observed.

The number of ribbon synapses per unit area of bipolar cell axon membrane differed little among bipolar cell sub‐classes. However, the density of amacrine cell conventional synapses was markedly lower for thin, horizontally‐oriented bipolar cell axons than for axons of other bipolar cell types.

Gap junctions were noted between bipolar cell axons of the same sub‐type. They are structurally similar to gap junctions between horizontal cells in Mustelus retina and to those found elsewhere in the nervous system.
The naso‐temporal division of the monkey's retina
Authors: Stone Jonathan , Leicester Jonathan , Sherman S. Murray
Published: May 2005

By sectioning one optic tract in each of four monkeys, and studying the distribution within each pair of retinas of the ganglion cells which remained after the affected ganglion cells had undergone retrograde degeneration, a description was obtained of the areas of a retina from which ganglion cells project to the ipsilateral and contralateral sides of the brain. Confirming previous work, ganglion cells in temporal retina were observed to project to the ipsilateral side, and cells in nasal retina to the contralateral side. It was noted, however, that ipsi‐ and contralaterally projecting areas of retina overlap along a vertically‐oriented median strip, which is about 1° wide, and is centred on the fovea. Within this strip ipsi‐ and contralaterally projecting cells intermingle. Some functional implications of this result are discussed.
Some observations on axonal degeneration resulting from superficial lesions of the cerebral cortex
Authors: Nauta H. J. W. , Butler Albert B. , Jane John A.
Published: May 2005

Thermal lesions were placed in the superficial cell layers of the neocortex in rats, cats, and tree shrews, and the resulting intracortical axonal degeneration was studied by the Fink‐Heimer technique and by electron microscopy. Certain features of the degeneration resulting from such lesions are common to each cortical area studied. Despite the finding of appreciable axonal degeneration spreading tangentially, the most conspicuous axonal degeneration in each area studied was noted to be oriented vertically with terminations occurring in the deeper layers, especially in the region of the large pyramidal cells of layer V. The bulk of the degeneration in the deeper layers was confined to an area coextensive with the boundaries of the superficial lesion.
A Golgi study of the rat dorsal lateral geniculate nucleus
Authors: Grossman A. , Lieberman A. R. , Webster K. E.
Published: May 2005

Golgi‐Kopsch and Cox preparations of albino rat dorsal lateral geniculate nucleus show two classes of neuron. Class A cells (assumed geniculocortical relay cells) have tufted dendritic arborizations, smooth primary dendrites, occasional excrescence clusters at dendritic branch points, irregular, small excrescences along distal dendrites, and myelinated axons. A subclass, more common medially, has long, smooth, radiating dendrites that branch sparsely.

Class B cells are small (c. 10 m̈ dia.) paucidendritic, and commonly bipolar. Their dendrites branch rarely and often run for long distances maintaining a uniform diameter. They are commonly orientated so that their dendrites extend either dorso‐ventrally or approximately antero‐posteriorly (i.e., parallel to either the representation of the vertical meridian or to the lines of projection). The dendrites bear complex appendages, often branched and several microns long, with en passant and terminal varicosities. Some class B cells also appear to have axons, but conclusive evidence is lacking. Class B cells may be intrinsic neurons, corresponding to the electrophysiologically identified inhibitory interneurons and to cells seen by electron microscopy to have presynaptic perikarya and dendrites. The complex dendritic appendages probably enter synaptic glomeruli within which they establish pre‐ and postsynaptic contacts. Whether class B cells are comparable with the Golgi type II cells of other thalamic nuclei remains an open question.

Three classes of axons are also described, and their possible origins considered.
The distribution of catecholamines within the inferior olivary complex of the gerbil and rabbit
Authors: Hoffman Donald L. , Sladek John R.
Published: May 2005

The inferior olivary complex of pre‐adult and adult gerbils and rabbits was examined with the histochemical fluorescence technique for the intraneuronal‐demonstration of monoamines. The observed patterns were compared directly to those seen in the rat. Dissimilar distributions of monoamine‐containing varicosities were observed between these mammalian species. These data support the belief that monoamine distribution as previously reported for the rat brain is not a complete model for other mammals. Also, a question is raised concerning the existence of the previously reported monoamine‐containing cell bodies in this nuclear complex.
Projections of the nuclei of the periaqueductal gray matter in the cat
Authors: Hamilton Betty L.
Published: May 2005

To obtain more evidence in support of the theory of tri‐nuclear division of the periaqueductal gray matter (PAG) in the cat, the projection systems of each of the nuclei were investigated. Direct current lesions were stereotaxically placed in the three nuclei of the PAG and the resulting fibers of degeneration were stained by reduced silver impregnation techniques. Degenerating axons from the lesion in the nucleus medialis were traced ventrally to the tegmentum in a radiating pattern and rostrally to the fields of Forel and the ventral tegmental area. Descending fibers were traced to their termination in the dorsal tegemental nucleus. Lesions in the nucleus dorsalis resulted in no radiating or descending fibers of degeneration, but a bundle of degenerating fibers running within the PAG could be followed to the level of the mesencephalic‐diencephalic junction. Here the axons terminated in the pretectal area and the lateral habenular nucleus. The pattern of degeneration was completely ipsilateral for the two nuclear lesions described above and predominately ipsilateral for the third nucleus, the lateralis. From it, all the ascending fibers were ipsilateral, but the heavy radiating fibers to the tectum and tegmentum did extend somewhat to the contralateral side. The large bundle of axons of degeneration ran rostrally within the PAG to diencephalic levels and divided into numerous fasciculi and terminated in the periventricular gray, the posterior hypothalamus and numerous thalamic nuclei. The evidence that each nucleus projects differently supports the theory of tri‐nuclear division of the PAG.
The distribution of septal projections to the hippocampus of the rat
Authors: Mosko Sarah , Lynch Gary , Cotman Carl W.
Published: May 2005

Terminal degeneration following lesions of the medial septal nucleus or of the contralateral hippocampus was mapped and compared with the distribution of acetylcholinesterase in the hippocampal formation of the rat. Previously unreported septal projections were found in the supragranular region of the dentate gyrus, an area which is also the locus of a dense band of acetylcholinesterase. This correspondence provides further support for the hypothesis that the enzyme is located in the septal efferents. These findings are combined with those of earlier workers in a hypothetical model of septo‐hippocampal relationships.
On the organization of cerebellar efferent pathways in the nurse shark (Ginglymostoma cirratum)
Authors: Ebbesson Sven O. E. , Campbell C. B. G.
Published: May 2005

The organization of the efferent fiber systems of the nurse shark cerebellum was studied with the Nauta and Fink‐Heimer techniques. Lesions of the cerebellar cortex produce a pattern of terminal degeneration restricted to select regions of the cortex, as well as ipsi‐ and contralateral cerebellar nuclei. We found no evidence of cortical axons projecting beyond the nuclei, to the medulla and spinal cord as has often been reported.

Lesions involving the cerebellar nucleus reveal three efferent pathways. The ipsilateral descending cerebello‐bulbar (IDC) pathway extends as far caudal as the first spinal segment and issues fibers to the lateral parts of the reticular formation. The brachium conjunctivum splits into a larger ascending limb (BCA) and a smaller descending one (BCD). The latter descends to the caudal medulla terminating along its course in the medial reticular formation. The ascending limb provides an input to (1) a nucleus we have tentatively labelled the “red nucleus,” (2) the trochlear nucleus, (3) the oculomotor nuclei, (4) the midbrain central gray, and (5) a poorly differentiated nucleus in the dorsal thalamus.
Morphology of the inferior olivary complex of the rhesus monkey (Macaca mulatta)
Authors: Bowman James P. , Sladek John R.
Published: May 2005

The morphology of the inferior olivary complex was determined in the rhesus monkey (Macaca mulatta). The position, configuration, and relations of each of its components were ascertained in serial transverse sections extending from caudal through rostral poles of the complex. The medial accessory nucleus was divided into seven cell groups (labeled a through g). The principal nucleus consisted of well‐developed dorsal, ventral, and lateral lamellae and a criterion was established for distinguishing the boundaries of each. This distinction was based upon the pattern of invagination that developed in the principal nucleus in progressing rostrally from its caudal pole. The dorsal and lateral lamellae each presented a characteristic pattern of major invaginations, while the ventral lamella did not. Finally, a detailed comparison was made of the inferior olivary complex of the monkey with that of the cat as determined by other investigators. It was shown that the medial and dorsal accessory nuclei of the two species appeared similar and that the major difference between these species concerns the principal nucleus.
Fiber organization at the posterior spinal cord‐rootlet junction in man
Authors: Sindou M. , Quoex C. , Baleydier C.
Published: May 2005

The authors have carried out serial section analysis in an attempt to elucidate the fiber organization at the posterior spinal cord‐rootlet junction in Man. In the peripheral segment of the rootlet, large and small caliber fibers have no particular organization. On the contrary, at the level of the spinal cord‐rootlet junction, small caliber fibers are re‐grouped in the ventro‐lateral region, whilst the large fibers are central and dorso‐medial. After consideration of published experimental data, which show that the small caliber fibers activate the nociceptive system, the authors have carried out in Man selective sections of the small fibers for antalgic reasons. These selective posterior rootlet sections ‐ operation called selective posterior rhizidiotomy ‐ result in an analgesia without suppression of tactile epicritic and conscious proprioceptive sensitivities.
Blood supply to brains of ungulates with and without a rete mirabile caroticum
Authors: Gillilan Lois A.
Published: May 2005

The arterial blood supply to brains of some ungulates representing the orders Artiodactyla and Perissodactyla differs from that in most other mammals. Either the internal carotid or vertebral artery or both may fail to carry blood to the brains of these animals. In pig, ox and sheep the proximal segment of the internal carotid artery is absent. Instead, branches of the internal maxillary and/or the external carotid artery feed into an arterial rete mirabile caroticum. A distal segment of the internal carotid artery is reconstituted from the rete mirabile which divides into a rostral and a caudal division. In the ox the rete mirabile receives additional branches at its caudal end from the vertebral and occipital arteries. In these three animals the basilar artery is fed from its rostral end through the caudal divisions of the internal carotid arteries of either side.

The horse has no rete mirabile. The internal carotid artery has a long course through its neck and forms an S‐shaped curve in the cavernous sinus before piercing the dura mater. It then divides into a rostral and a caudal division. The basilar artery in the horse is formed at its caudal end by the union of cerebral rami of the occipital arteries.

The patterns of the superficial cerebral arteries in all the ungulates studied have distinct submammalian characteristics. These are evidenced by the multiple origins of the middle cerebral and posterior cerebral arteries and the presence of arterial circles in the basilar artery.

The principal portion of the arterial rete mirabile always lies enmeshed in the venous plexus of the cavernous sinus. Additional venous plexuses are found intimately related to the extracranial rete mirabile in the pig and the basisphenoid portion of the arterial rete mirabile in the ox.
The optic tectum of a perciform teleost II. Fine structure
Authors: Laufer Miguel , Vanegas Horacio
Published: May 2005

The fine structure of the six layers in the optic tectum of the teleost Eugerres plumieri has been studied with the electron microscope. In the stratum marginale, parallel nonmyelinated axons synapse on spines of thick dendrites of pyramidal cells, resembling the organization of the cerebellar cortex molecular layer. In the stratum opticum, two populations of fibers are described which differ in diameter, position and origin. In the stratum fibrosum et griseum superficiale, characteristic terminals belonging to optic nerve afferents are large and irregular, contain pale mitochondria with sparse cristae and large empty spaces, abundant round vesicles, and, occasionally, dense core vesicles. Optic nerve terminals synapse on pyramidal cells, as well as on dendritic profiles of other cell types, without a glomerular organization. Most cell types observed in Golgi preparations have been identified. Particular emphasis is placed on the description of different types of terminals and their synaptic relations.
Rubrospinal projections in the rat
Authors: Brown Leroy T.
Published: May 2005

Following stereotaxically placed lesions in the magnocellular and parvicellular portions of the red nucleus in a series of young adult albino rats, the site of termination of the rubrospinal fibers in the cervical cord has been studied using the Nauta‐Gygax and Fink‐Heimer silver methods and electron microscopy.

Following three days survival the degenerating rubrospinal tract could be identified in the dorsal aspect of the lateral funiculus, principally contralateral to the lesion. Degenerating axons could be seen projecting to the base of the dorsal horn and intermediate regions of the ventral horn. Degenerating synaptic terminals were electron dense, contained remnants of synaptic vesicles and mitochondria, and usually made synaptic contact with small to medium size dendrites.

This study finds that the rubrospinal tract in the rat projects chiefly to the base of the dorsal horn and intermediate regions of the ventral horn. The system forms axodendritic synapses with spinal neurons. This projection is in contrast to the dorsomedial projection of corticospinal terminals seen in this species. The significance of these apparently diverging pathways is discussed.
The retrograde intraaxonal transport of horseradish peroxidase in the chick visual system: A light and electron microscopic study
Authors: LaVail Jennifer H. , LaVail Matthew M.
Published: May 2005

Retrograde transport of horseradish peroxidase (HRP) from the region of retinal genglion cell axon terminals back to the cell bodies has been studied by light and electron microscopy. After injection of HRP into the chick optic tectum, it was taken up by axon terminals and unmyelinated axons as well as by other processes and cell bodies of the outer tectal layers. Subsequently the HRP was obseved in vesicles, multivesicular bodies, cup‐shaped organelles and small tubules within axons in the stratum opticum, optic tract, optic nerve and optic fiber layer of the retina with accumulation in the retinal ganglion cell bodies. Pinocytosis of extracellular HRP along the axon shaft was rare. After a short postinjection interval, HRP was found in organelles within the axons of the optic nerve but not in the extracellular spaces. After larger injections or longer postinjection intervals, extracellular HRP diffused from the injection site to the back of the eye, but none was found in the extracellular spaces of the retina; ganglion cells were the only cells of the retina which contained HRP product. HRP disappeared from the cell bodies 3–4 days after transport. These findings suport the concept of intraaxonal retrograde movement of HRP.

Within axons the vesicles carrying HRP frequently were partially or completely surrounded by a regualr array of microtubules. Doses of colchicine greater than 5–10 µ/eye administered 4 days before tectal injection of HRP interfered with the uptake and/or transport of HRP. HRP also moved in an anterograde direction in membrane‐bound vesicles within the ganglion cell axons, although apparently more slowly and in smaller quantities than in the retrograde direction.

The localization of HRP in neurons of the isthmo‐optic nucleus following intravitreal injections has also been studied. The marker enzyme was found in neuronal cell bodies 4 hours after injection, indicating a rate of retrograde transport of at least 84 mm/day in these neurons.