bluuebunny/crossref_metadata_2025 huggingface dataset:
Counteracting the Nogo Receptor Enhances Optic Nerve Regeneration If Retinal Ganglion Cells Are in an Active Growth State
Authors: Fischer Dietmar , He Zhigang , Benowitz Larry I.
Published: February 2004

Mature retinal ganglion cells (RGCs), like other CNS neurons, cannot regrow injured axons into a myelin-rich environment. If stimulated by macrophage-derived factors, however, RGCs can regenerate their axons for considerable distances through the distal optic nerve. Using this “sensitized background,” we investigated the effects of either increasing the expression or suppressing the activity of the Nogo receptor (NgR). NgR mediates the growth-inhibiting effects of three myelin proteins, Nogo, OMgp (oligodendrocyte-myelin glycoprotein), and MAG (myelin-associated glycoprotein). Transfecting growth-sensitized RGCs with adeno-associated viruses expressing a dominant-negative form of NgR (NgRDN) increased axon regeneration several-fold; however, when the growth program of RGCs was not activated, NgRDNexpression had no beneficial effects. Overexpression of wild-type NgR blocked almost all regeneration from growth-sensitized RGCs and caused axons proximal to the lesion site to retract. We conclude that gene therapy is an effective approach to enhancing axon regeneration in the CNS and that inactivation of NgR functioning greatly enhances axon regeneration provided the intrinsic growth program of neurons is activated.
A Single Infusion of Brain-Derived Neurotrophic Factor into the Ventral Tegmental Area Induces Long-Lasting Potentiation of Cocaine Seeking after Withdrawal
Authors: Lu Lin , Dempsey Jack , Liu Shirley Y. , Bossert Jennifer M. , Shaham Yavin
Published: February 2004

Cocaine addiction in humans is associated with long-term propensity to relapse. Using a rat relapse model, we found that cocaine seeking induced by exposure to cocaine-associated cues progressively increases after withdrawal. This progressive increase is associated with increases in brain-derived nerve growth factor (BDNF) levels within the mesolimbic dopamine system. Based on these findings, we studied whether BDNF infusions into the ventral tegmental area (VTA), the cell body region of mesolimbic dopamine neurons, would potentiate cocaine seeking after withdrawal. Rats were trained to self-administer cocaine for 10 d, and cocaine seeking was measured in extinction tests 3, 10, or 30 d after withdrawal. During testing, rats were exposed to contextual cues that had predicted cocaine availability during training, and lever presses resulted in contingent presentations of a discrete tone-light cue that was previously temporally paired with cocaine infusions. BDNF (0-0.75 μg/site) or nerve growth factor (NGF; 0-0.75 μg/site) was infused into the VTA 1-2 hr after the last self-administration session. To examine the role of the mitogen-activated protein kinase (MAPK) pathway in BDNF effects, U0126 (1 μg/site), an MEK inhibitor, was used. A single intra-VTA infusion of BDNF, but not NGF, induced long-lasting enhancement of cocaine seeking for up to 30 d, an effect reversed by U0126. In contrast, neither BDNF infusions into the substantia nigra, nor acute intra-VTA BDNF infusions 2 hr before testing on day 3 of withdrawal, were effective. These data suggest that BDNF-mediated neuroadaptations in mesolimbic areas are involved in the persistent cocaine seeking induced by exposure to drug cues after withdrawal.
Neuroprotective Role of a Proline-Rich Akt Substrate in Apoptotic Neuronal Cell Death after Stroke: Relationships with Nerve Growth Factor
Authors: Saito Atsushi , Narasimhan Purnima , Hayashi Takeshi , Okuno Shuzo , Ferrand-Drake Michel , Chan Pak H.
Published: February 2004

The Akt signaling pathway contributes to regulation of apoptosis after a variety of cell death stimuli. A novel proline-rich Akt substrate (PRAS) was recently detected and found to be involved in apoptosis. In our study, Akt activation was modulated by growth factors, and treatment with nerve growth factor (NGF) reduced apoptotic cell death after ischemic injury. However, the role of the PRAS pathway in apoptotic neuronal cell death after ischemia remains unknown. Phosphorylated PRAS (pPRAS) and the binding of pPRAS/phosphorylated Akt (pPRAS/pAkt) to 14-3-3 (pPRAS/14-3-3) were detected, and their expression transiently decreased in mouse brains after transient focal cerebral ischemia (tFCI). Liposome-mediated pPRAS cDNA transfection induced overexpression of pPRAS, promoted pPRAS/14-3-3, and inhibited apoptotic neuronal cell death after tFCI. The expression of pPRAS, pPRAS/pAkt, and pPRAS/14-3-3 increased in NGF-treated mice but decreased with inhibition of phosphatidylinositol-3 kinase and the NGF receptor after tFCI. These results suggest that PRAS phosphorylation and its interaction with pAkt and 14-3-3 might play an important role in neuroprotection mediated by NGF in apoptotic neuronal cell death after tFCI.
Disruption of Endocannabinoid Release and Striatal Long-Term Depression by Postsynaptic Blockade of Endocannabinoid Membrane Transport
Authors: Ronesi Jennifer , Gerdeman Gregory L. , Lovinger David M.
Published: February 2004

Activation of the CB1 cannabinoid receptor inhibits neurotransmission at numerous synapses in the brain. Indeed, CB1 is essential for certain types of both short- and long-term synaptic depression. It was demonstrated recently that CB1 is critical for activity-dependent long-term depression (LTD) at glutamatergic corticostriatal synapses in acute brain slice preparations. Here, we show that CB1 activation is necessary, but not solely sufficient, for induction of LTD and that the requisite signaling by endocannabinoids (eCBs) occurs during a time window limited to the first few minutes after high-frequency stimulation delivery. In addition, we have applied intracellularly anandamide membrane transporter inhibitors to provide novel evidence that postsynaptic transport mechanisms are responsible for the release of eCBs from striatal medium spiny neurons. These findings shed new light on the mechanisms by which transient eCB formation participates in the induction of long-lasting changes in synaptic efficacy that could contribute to brain information storage.
Quo Vadis Bioinformatik, neue Konzepte und Arbeitsbereiche (Quo Vadis Bioinformatics – New Concepts and Areas)
Authors: Karas Holger , Tysiak Michael , Wingender Edgar
Published: February 2004

Bioinformatik war einer der ganz großen Trends der letzten Jahre und ist in veränderter Form immer noch ein wichtiger Bereich. Allerdings haben sich die Anforderungen gewandelt, waren früher "self-made" Informatiker für die meisten Bereiche ausreichend, so ist der Anspruch an den Bioinformatiker deutlich gestiegen aber auch klarer formuliert, was in der Vergangenheit nicht immer der Fall war.
Online Fehler-Erkennung und schnelle Wiederherstellungs-Techniken für zuverlässige eingebettete Prozessoren (Online Error Detection and Fast Recover Techniques for Dependable Embedded Processors)
Authors: Pflanz Matthias
Published: February 2004

Die Dissertation präsentiert neue Verfahren zur online Observierung und parallelem Check von Prozessoren durch Verfeinerung und Verbesserung bekannter Techniken und Methoden sowie Einführung neuer Ideen. Motivation war die Entwicklung von Techniken zur Fehlererkennung im selben Maschinenzyklus. Des Weiteren werden Verfahren zur schnellen Fehlerkompensation vorgestellt. Ziel ist die Erhöhung der Zuverlässigkeit von Prozessoren speziell für sicherheitskritische Systeme.
Structures, Energies and Electronic Properties of Interaction of Hydrogen Halides with Pentamer Water Cluster
Authors: Nirmala V. , Kolandaivel P.
Published: February 2004

Molecular orbital and density functional theory calculations have been performed to study the interaction of hydrogen halides with hydrogen bonded cluster of water pentamer, i.e. HX·(H2O)5 (where X = F, Cl, Br). Second order Møller–Plesset perturbation theory of ab initio method, B3LYP level of theory of DFT method, implementing 6-311++G** basis set have been used for the calculations. The strength of hydrogen bonds have been studied using the interaction energies of the water molecules, which were calculated after eliminating the basis set superposition error (BSSE) by Boys Counterpoise (CP) correction method and the stability of this cluster with hydrogen halides has been studied using the dipole moments, charge transfer and the topological properties. The chemical hardness and chemical potential have been calculated for the above cluster with hydrogen halides and tested the principle of maximum hardness.
Genetic Engineering
Authors: Nagabhushan Tattanahalli , Narula Satwant
Published: February 2004

The article contains sections titled:

1.Introduction2.DNA Cloning Techniques2.1.Cloning Genomic DNA Fragments inEscherichia coli2.1.1.Plasmids as Cloning Vectors2.1.2.Bacteriophage Lambda as a Cloning Vector2.1.3.Cosmids as Cloning Vectors2.1.4.Bacteriophage M13 as a Cloning Vector2.2.Synthesis of cDNA3.Methods for Screening and Identifying Recombinant Clones from a Library3.1.Nucleic Acid Hybridization3.2.Immunodetection Techniques3.3.Sequencing Techniques for DNA4.Expression of Recombinant Clones4.1.Heterologous Gene Expression in Prokaryotes4.1.1.Escherichia coli4.1.2.Bacillus subtilis4.2.Heterologous Gene Expression in Lower Eukaryotes (Fungi)4.2.1.Yeast (Saccharomyces cerevisiae)4.2.2.Other Yeast Systems4.2.3.Filamentous Fungi4.3.Heterologous Gene Expression in Higher Eukaryotes4.3.1.Mammalian Cells4.3.1.1.Vectors4.3.1.2.Promoters and Enhancers4.3.1.3.Chromosomal Gene Amplification4.3.2.Insect Systems4.3.3.Plant Systems4.3.3.1.Plasmid Vectors4.3.3.2.Plant Promoters5.Applications of Recombinant DNA Technology5.1.Therapeutic Agents5.2.Vaccines5.3.Genetically Altered Organisms5.3.1.Transgenic Animals5.3.2.Transgenic Plants5.4.Gene Therapy5.5.Diagnostics6.Regulatory and Safety Aspects7.Glossary of Special Terms
Nucleic Acids
Authors: Burtscher Helmut , Berner Sibylle , Seibl Rudolf , Mühlegger Klaus
Published: February 2004

The article contains sections titled:

1.Introduction2.Structure2.1.Structure of DNA2.2.Structure of RNA3.Properties3.1.Physical and Chemical Properties3.2.Interaction with Proteins4.Biosynthesis and Biological Function4.1.DNA Replication4.2.Gene Expression4.2.1.Transcription4.2.2.Translation4.3.Modification and Degradation4.4.Recombination4.5.DNA Repair4.6.Nucleic Acids as Enzymes5.Isolation, Purification, and Transfer6.Analysis of Nucleic Acids7.Chemical Synthesis7.1.Synthesis Strategy7.2.Protecting Groups7.3.Functionalization of the Support7.4.Methods of Synthesis7.5.Cleavage of Protecting Groups and Purification of Oligonucleotides7.6.Synthesis of Modified Oligonucleotides8.Uses8.1.Hybridization Techniques for Nucleic Acid Detection8.2.Labeling and Detection Systems8.3.Amplification Systems8.4.Applications of Probe Technology9.Nucleosides and Nucleotides9.1.Nucleosides9.2.Nucleotides9.3.Therapeutically Important Nucleoside and Nucleotide Derivatives
Process‐Scale Chromatography
Authors: Jagschies Günter
Published: February 2004

The article contains sections titled:

1.Introduction2.Chromatographic Techniques2.1.Adsorptive Methods2.1.1.Ion‐Exchange Chromatography2.1.2.Affinity Chromatography2.1.3.Hydrophobic Interaction Chromatography2.1.4.Reversed Phase Chromatography2.2.Gel Filtration3.Downstream Strategy3.1.Number of Preparative Steps3.2.Preparation of an Optimal Raw Material3.3.Development of a Chromatographic Purification System3.3.1.Screening of Chromatographic Methods (Method Scouting)3.3.1.1.The Gel Bank3.3.1.2.Experimental Data3.3.2.Logical Sequence of Chromatographic Steps3.3.2.1.Selection Criteria3.3.2.2.The Starting Step3.3.2.3.Subsequent Steps4.Optimization4.1.Purpose of Optimization4.2.Optimization Parameters4.2.1.Resolution4.2.2.Throughput4.3.Optimization of Ion‐Exchange Chromatography4.4.Optimization of Affinity Chromatography4.5.Optimization of Hydrophobic Interaction Chromatography4.6.Optimization of Gel Filtration5.Scaling Up5.1.Transfer Protocol5.2.Practical Examples and Case Studies5.3.Dimensioning of a Purification Cycle6.Process‐Scale Chromatography Plants6.1.Basic Design Requirements6.2.Plant Design6.2.1.The Chromatography Column6.2.2.Process Monitoring6.2.3.Pumps and Valves6.2.4.Automation and Safety Devices6.3.Effects of Apparatus on Separation7.Quality Assurance8.Developments
Freeze‐Drying
Authors: Oetjen Georg‐Wilhelm
Published: February 2004

The article contains sections titled:

1.Introduction1.1.Goals of Industrial Freeze‐Drying1.2.Steps of the freeze‐drying process1.3.Chemical Engineering Tasks in Industrial Freeze‐Drying2.Process Steps2.1.Freezing2.2.Main Drying2.3.Transition from Main to Secondary Drying (SD)2.4.Secondary Drying2.5.Packing and Storage3.Temperatures and Pressures3.1.Barometric Temperature Measurement3.2.Pressure During Secondary Drying3.3.Water‐Vapor Flow3.4.Residual Moisture Content3.5.Uniformity of Temperatures, Pressures, and Product4.Structures of Frozen and Dried Products4.1.Influence of Freezing Method and Excipients4.2.Methods of Structure Analysis5.Industrial Freezing and Freeze‐drying Installations5.1.For Pharmaceutical Products5.2.Regulatory Requirements for Pharmaceutical Plants5.3.Food Plants5.4.Process Automation5.4.1.Prerequisites for Process and Plant Automation5.4.2.Control of the Process and the Plant by Thermodynamic Data Measured During the Process: Thermodynamic Lyophilization Control5.4.3.Transfer of Pilot Plant Data to Production6.Some Examples of Freeze‐drying Processes6.1.For Pharmaceuticals6.1.1.Process Reproducibility6.1.2.Shorter Drying Cycle6.1.3.Selection of Exipients6.2.For Food6.3.For Metal Oxides, Ceramic Powders7.Economic and Social Aspects, Outlook
Polymer Nanocomposites with Fullerene‐like Solid Lubricant
Authors: Rapoport L. , Nepomnyashchy O. , Verdyan A. , Popovitz‐Biro R. , Volovik Y. , Ittah B. , Tenne R.
Published: February 2004

Recent experiments showed that the addition of inorganic fullerene‐like (IF) WS2 or MoS2 solid lubricant nanoparticles in oil, grease or impregnated into porous matrix provides remarkable lubricating properties of friction pairs in a wide range of operating conditions. Inorganic nanoparticles filled polymer composites show low friction and high wear resistance. This work reports the first attempt to fill polymers with hollow solid lubricant nanoparticles. It was found that application of the IF solid lubricant nanoparticles leads to a considerable improvements in the tribological behavior of the nanocomposites. The morphology of the surface layers and the mechanism of the friction reduction by the IF nanoparticles are discussed.
Demonstration of Carbon Nanotube Coated Metals Reinforcing Polymer Matrix Composites
Authors: Vander Wal R.L. , Hall L.J.
Published: February 2004

Advancements in interfacial bonding will improve all types of polymer matrix composites (PMCs) using regular carbon fibers, metals or metal meshes by significantly improving strength, toughness, thermal conductivity, gas impermeability and electrical conductivity. In this article we demonstrate a distributed interface between carbon nanotube (CNT) coated stainless steel (SS) metal foils and a host polymer matrix. With the metal acting as both catalyst and support, the CNTs bridge the interface between the two dissimilar materials to create a volumetrically distributed 3‐dimensional interface.
Sol–Gel Coatings as Active Barriers to Protect Ceramic Reinforcement in Aluminum Matrix Composites
Authors: Rams J. , Ureña A. , Campo M.
Published: February 2004

Silica obtained through a sol–gel process is used as a coating for ceramic reinforcements (SiC) in aluminium matrix composite materials. The interaction between molten aluminium and the coated particles during material casting can be controlled by means of the thermal treatment given to the coating. Wettability is increased because the coating reacts with molten aluminium, and the formation of the degrading aluminium carbide is inhibited.
Fabrication of Mullite Powders by a Novel Processing
Authors: Tang Y.F. , Feng L. , Chen Y.F. , Li A.D.
Published: February 2004

A novel and general processing (heterogeneous nucleation and growth processing) was used to prepare composite coating particles with homogeneous component distribution. Composite coating particles consisting of α‐Al2O3 cores with an outer amorphous silica layer were prepared by this processing using an ethanol suspension containing ammonia, tetraethylorthosilicate and α‐Al2O3. Fine mullite powders (d50 = 0.73 μm) were fabricated by calcinating these particles at 1500 °C for 2 h.
Building The Data Warehouse For Materials Selection in Mechanical Design
Authors: Li Y.
Published: February 2004

The materials selection for mechanical design is a data‐intensive decision‐making task. It would be highly desirable to take full advantages of the latest data management techniques to support it. The data warehousing, as a new information management technology, has the eminent power of supporting a large‐scale data integration and decision‐making practice. Therefore the data warehousing is an attractive option to be used for the materials selection process.
Influence of Boron on the Microstructure of Polymer Derived SiCO Ceramics
Authors: Klonczynski A. , Schneider G. , Riedel R. , Theissmann R.
Published: February 2004

The thermal decomposition and crystallisation behaviour of boron containing siliconoxycarbide (SiCO) ceramics were studied. The samples were prepared by pyrolysis of SiO2/B2O3 filled poly(dimethylsiloxanes) at 1300°C and subsequent annealing at T > 1300°C. TEM and XRD investigations show the formation of β‐SiC during annealing at 1300°C. The resulting material can be described as a borosilicate glass with homogeneously dispersed nano β‐SiC crystals.
Effectiveness of Surface Composite Layers on Impact Resistance of Brittle Materials
Authors: Kim Y. , Zhu S. , Kagawa Y. , Kasano H.
Published: February 2004

Single and double layers of woven fabric Al2O3 fiber‐Al2O3 matrix composites are used as a surface protective layer for a brittle material, borosilicate glass substrate. The effect of a thin damage‐tolerant surface composite layer on the damage caused by steel ball projectiles is examined. Damage behavior of the surface composite layer‐bonded specimen with impact speed of 40 and 110 m/s shows significant effect of the composite layer on the damage. It is clearly demonstrated that the concept of a thin surface composite layer is effective for reducing impact damage on the surface of brittle materials.
Tuning the Refractive Index of Polymers for Polymer Waveguides Using Nanoscaled Ceramics or Organic Dyes
Authors: Böhm J. , Haußelt J. , Henzi P. , Litfin K. , Hanemann T.
Published: February 2004

Plastic Optical Fibers (POF) show advantageous properties like high flexibility and their cost advantage in comparison to glass fibers. The refractive indices of core and cladding have to be modified in order to get total reflectance. Thus, there is a strong demand for refractive index adjustable polymers with improved transmission properties in the visible and the NIR range. Inorganic nanosized particles or organic dyes homogeniously dispersed or solved in the polymer matrix allow a tailored increase or decrease of the refractive index of various polymers.
Materials Design for Acoustic Liners: an Example of Tailored Multifunctional Materials
Authors: Gasser S. , Brechet Y. , Paun F.
Published: February 2004

Relying on a model allowing to predict mechanical properties and acoustic absorption of a regular f.c.c stacking of hollow spheres, and on a functional analysis of acoustic liners for airplane engines, a methodology for optimal design of a taylored multifunctional material is proposed.
Optical and Dielectric Anisotropy in Polyimide Nanocomposite Films Prepared from Soluble Poly(amic diethyl ester) Precursors
Authors: Kim Y. , Goh W.H. , Chang T. , Ha C.‐S. , Ree M.
Published: February 2004

Optical and dielectric anisotropy of the polyimide nanocomposite films prepared from soluble poly(amic‐diethyl ester) precursors has been studied using a prism coupling technique. The composite films showed nonlinear dependence of in‐plane and out‐of‐plane refractive indices (dielectric constants) on the composition. Consequently the in‐plane dielectric constant of the composite films was not much reduced owing to the still high in‐plane orientation of the rod‐like polyimide, leading to the quite high dielectric anisotropy.
Multi‐Criteria Material Selection in Engineering Design
Authors: Sirisalee P. , Ashby M.F. , Parks G.T. , Clarkson P.J.
Published: February 2004

Material selection in real‐world problems normally entails considering several, usually conflicting, design criteria/objectives. Thus, a designer has to strike a balance between these objectives to find the best compromise solution for the particular application. A novel design support tool, the exchange constant chart, has been developed in order to assist designers selecting materials in such multi‐criteria situations. Two case studies are presented to illustrate the use of this tool.
Powder Metallurgical Processing of Intermetallic Gamma Titanium Aluminides
Authors: Gerling R. , Clemens H. , Schimansky F.P.
Published: February 2004

Intermetallic γ‐TiAl‐based alloys represent a new class of light‐weight structural materials for use at high temperatures. Because of their unique properties these alloys are considered for applications in aerospace and automotive industries. During the last decade both, alloy development and materials processing progressed significantly. New materials and powder metallurgy (PM) have formed a symbiosis since many decades. In fact, PM is an ancient technology which has been used for the processing for almost every metal or ceramic material. Therefore, it is hardly surprising that PM plays an important role in research and development of γ‐TiAl‐based alloys.
Research Directions in Magnesium Corrosion Arising from the Wolfsburg Conference
Authors: Atrens A.
Published: February 2004

Following a recent review article in this journal and a keynote lecture at “6th International Conference on Magnesium Alloys and Their Applications” suggestions for research directions in magnesium corrosion are provided and discussed.
Heavy Metals in Saale Sediments — Changes in the Contamination since 1991
Authors: Zerling Lutz , Hanisch Christiane , Junge Frank W. , Müller Ansgar
Published: February 2004

Based on the hydrographical and geological conditions of the river Saale catchment area, the regional geogenic background values are given for heavy metals in fluviatile sediments. They serve as a yardstick for evaluating the current sediment load of the Saale. Compared with the data from the 1990s, level reductions in the Saale can only be proven for the main contaminants Hg and Cr. By contrast, heavy metal levels in the formerly highly contaminated Weiße Elster river basin have clearly decreased, in particular Cd, Zn, Ag, and U. At the same time, increased manganese levels throughout the river system indicate a reduction in organic loads and an increase in oxygen levels.
The Difficult Assessment of Heavy Metal Contamination of Soils and Plants in Elbe River Floodplains
Authors: Krüger Frank , Gröngröft Alexander
Published: February 2004

The investigations on total sums of heavy metals indicated that topsoils in the floodplains in the German part of the river Elbe are in part markedly enriched. The contamination exceeds the action values of the Federal Soil Protection and Contaminated Site Ordinance. Looking on known concentrations of heavy metals in the pasture vegetation, however, threshold values for fodder are not exceeded in most cases. As livestock takes up a part of contaminants by inhalation and ingestion of soil particles and as the contamination in the vegetation is variable in space and time, the actual risk of heavy metal transfer in the food chain has needs to be studied.
Entry and Deposits of Suspended Particulate Matter in Groyne Fields of the Middle Elbe and its Ecological Relevance
Authors: Schwartz René , Kozerski Hans‐Peter
Published: February 2004

Groynes are widespread in the Middle Elbe River. They are important for navigation during low water. Due to the significant decrease of the flow velocity in comparison to the main stream, sedimentation of fine organic matter in the groyne fields (the area between two groynes) is high. The amount and location of sedimentation depend on hydraulic processes. The present paper presents the results of the actual (recent) sedimentation, and of the matter deposited in a typical groyne field in the Middle Elbe at Havelberg (German navigation km 420.9/river length 785.4). Furthermore, the development of water quality and suspended matter is described by the interpretation of data from an adjacent official water quality measuring point. From an ecological point of view, the high loads of nutrients and pollutants of the fine‐grained sediment (mud) are of special interest. A close correlation was observed between the nutrient and pollutant load with the fine‐grain size percentage and the content of particulate organic matter (POM). Groyne fields act as temporary sediment deposits, and are a latent danger to the ecosystem river Elbe. During construction work carried out at the river and extreme floods the mud could be remobilized, leading to a decrease in the water quality of the Elbe. Therefore, it is desirable that the organic mud should be removed from the river and deposited in a controlled landfill.
Investigations into the Distribution of Element Concentrations in a Recent Dam and their Seasonal and Hydrographical Correlation (Bitterfelder Muldestausee, Saxony‐Anhalt)
Authors: Junge Frank W. , Jendryschik Karl
Published: February 2004

Examination of the levels of dissolved matter in layered water bodies (case I) of the Bitterfelder Muldestausee (dam) showed a specific distribution of the element concentrations largely depending on the ion potential (inner migration factor) and the degree of saturation for oxygen (outer migration factor). During the summer, the elements (and/or ions) Al, PO‐P, V, As, Mo, B, Ce, Y, Zr, Sb, Cr characterized by a high ion potential and a high energy coefficient chiefly accumulate in the epilimnion rich in oxygen. However, the hypolimnion, which is free of oxygen, features increased concentrations of the dissolved elements (and/or ions) Mn, Co, NH‐N, Zn, Cd, Cu, and Ni. From the beginning of the hydrologic winter (case II), the lake water is completely intermingled with the cold incoming Mulde water streams, and the anoxic conditions of the deep water zones disappear. The distribution of element concentrations intermingled in the water body is characterized by processes of dilution and increases in concentration as well as by element‐specific precipitation and reverse dissolution.
Pore Water Composition as Device for the Detection of Origin and Flow Direction of Soil Water in Alluvial Soils of the Middle Elbe River
Authors: Schwartz René , Gröngröft Alexander , Miehlich Günter
Published: February 2004

The aim of the present article was to show the spreading of the Elbe‐borne pore water in the diked area of the lower Middle Elbe River floodplain at Lenzen (Brandenburg). The distribution was exhibited by comparing the composition of the river water of the rivers Elbe and Löcknitz, as well as groundwater and soil solution of the adjacent floodplain. It became evident that the sites in the recent flood area did not inevitably reflect soil solution compositions of closest similarity to conditions of the Elbe water. The high relative elevation of the stream bank and the plateau site in relation to the mean water level of the river Elbe and their dominant sandy substrate caused a great influence of precipitation water. Within the diked area of the floodplain, the soil solution analyses were sufficient to derive the maximum infiltration of the stream water. At 250 m distance of the Elbe dike, the soil solution still clearly exhibited the features of the Elbe water, and at 450 m distance, a transition zone equally influenced by the groundwater of the river Elbe and the river Löcknitz was detected. Finally, at 1.3 km distance from the dike in the relictic floodplain, the groundwater was definitely Löcknitz‐borne, although the hydraulic potentials of the Elbe were still effective. The presented results will allow to make predictions about the effects of the imminent dike realignment to the soil solution on the adjacent floodplain.
Colloidal Particles in Sediment Pore Waters: Particle Size Distributions and Associated Element Size Distribution in Anoxic and Re‐oxidized Samples, Obtained by FFF‐ICP‐MS Coupling
Authors: v. d. Kammer Frank , Baborowski Martina , Tadjiki Soheyl , v. Tümpling jr. Wolf
Published: February 2004

Pore water samples from sediment cores of the rivers Saale and Elbe were examined for variations of colloidal heavy metal associations during transition from anoxic to oxic conditions. Asymmetric flow‐field flow fractionation coupled to ICP‐MS was used to collect size distributions and element‐size distributions simultaneously. The data obtained reveal an increasing amount of colloidal bound main and trace elements in the pore waters during oxidation. Although there was a significant trend to increasing colloid concentrations and colloidal bound heavy metals over the observed 48 hour period of oxidation, differences between both samples were obvious.
Depth Distribution of Chlorinated and Polycyclic Aromatic Hydrocarbons in Floodplain Soils of the River
Authors: Witter Barbara , Winkler Marcus , Friese Kurt
Published: February 2004

Depth profiles of various organic micropollutants were measured in floodplain soils of the river Elbe, Germany. The study area lies in the former East Germany (GDR) and displays elevated concentrations of pesticides and polycyclic aromatic hydrocarbons. Depth distributions were found to vary at different sampling points and among the individual compounds, which could only partly be explained by comparing normalized concentrations (organic carbon). Metabolization, mobilization, and effects of sedimentation and erosion also need to be taken into account to understand the contaminant patterns found in the different profiles.
ELBIS, an Internet Information System on the Water Quality of the River Elbe
Authors: Frank Barbara , Geschwandtner Dirk , Janson Katja , Löffler Joachim
Published: February 2004

The Elbe information system ELBIS provides an elaborate view of the water quality of the Elbe river system. Since July 2001 it can be used by the general public via internet. www.elbis.de supplies information on the water quality and related topics for the river Elbe. The geographical information system (GIS) ELBIS is based upon extensive data from measuring campaigns. The ARGE Elbe (Arbeitsgemeinschaft zur Reinhaltung der Elbe/Elbe River Water Quality Board) supplies the measured values of 218 different variables. The ELBIS generally includes data from 1994 onwards, for the measuring point Schnackenburg, however, the values are available back to 1985. Annual data updates of the database would be necessary to ensure the system's topicality. The continuous time series enables the assessment of the water pollution load of the river Elbe.

In order to make the information available to a broad circle of users, ELBIS was created as an internet information system. To simplify its usage a broad meta‐information and navigation concept was developed. The user interface enables data to be accessed by laymen as well as specialists. An important element of the user interface is the geographical component: Via a digital map the user can specify which area he or she is interested in. The data basis of the ELBIS is held in a database management system. Thus new data can be added easily.
The Effects of Nutrient Concentrations in the River Elbe
Authors: Guhr Helmut , Spott Dieter , Bormki Gerald , Baborowski Martina , Karrasch Bernhard
Published: February 2004

The nutrient turnover and the resulting development of phytoplankton biomass were investigated during four river surveys in the free‐flowing reach of the river Elbe under almost constant hydrological and meteorological conditions taking into account the transport time and the time of day. The chlorophyll‐a concentration was found to increase by a factor of between 3 and 6 depending on the season, while the biomass load increased by a factor of up to 18. The concentrations of dissolved silicate and dissolved total phosphate behaved oppositely to this development, while the levels of particulate bound nutrients rose accordingly. Depending on the season, 6…23% of the total bound nitrogen was found to be removed from the river by denitrification. The river Saale contains the highest load of nutrients of all the tributaries. At the end of the investigated reach, algae biomass accounts for as much as 75% of the POC.
Extracellular Enzyme Activity in the River Elbe during a Spring Flood Event
Authors: Karrasch Bernhard , Bormki Gerald , Herzsprung Peter , Winkler Markus , Baborowski Martina
Published: February 2004

The ecological balance of rivers can be significantly disturbed by floods, increasing the supply of allochthonous material and energy to the fluvial planktonic food web. During spring flooding in the Elbe in 1999, various physicochemical (pH, conductivity, suspended particulate matter (SPM), particulate and dissolved organic carbon (DOC, POC), inorganic nutrients) and biological parameters (concentration of chlorophyll‐a, abundance and biomass of bacteria) were studied in connection with the microbial self‐cleaning capacity (dissolved and particle‐associated extracellular enzyme activity of ten different enzymes). The pattern of dissolved and particulate material was found to differ greatly (regarding dilution and allochthonous input dynamics), with biological parameters displaying partly differing patterns owing to their bioactivity. Hydrolytic activity was detected for all the enzyme categories investigated, with especially high breakdown rates being determined for proteins containing leucine, arginine, and tyrosine. The overall activities of all the microbial extracellular enzymes studied proved to be dominated by the ectoenzymes ((62.8 ± 13.6)%) associated with particulate (particles, aggregates, and bacterial cell walls). The resulting ecological implications for microbial self‐cleaning processes in rivers are discussed.
Free and Particle‐associated Extracellular Enzyme Activity and Bacterial Production in the Lower Elbe Estuary, Germany
Authors: Karrasch Bernhard , Ullrich Sören , Mehrens Maren , Zimmermann‐Timm Heike
Published: February 2004

A high abundance of particles and aggregates is a characteristic of estuaries and may represent important loci of increased bioproductivity and microbial activity. From a survey performed in the Elbe estuary, particle concentration (using a particle counter), bacterial biomass and abundance (AODC method), bacterial production rates ([3H] thymidine method) and the microbial extracellular enzyme activity of 11 enzymes (MUF and MCA method) were determined with particular respect to their relationship to particles and aggregates (sizefractionated). Although higher particle abundance was found compared to other sections of the river Elbe, neither relative nor absolute bacterial activity associated with particles and aggregates was enhanced. The activity of free dissolved microbial enzymes was found to dominate the breakdown of organic material. The productivity of free dispersed bacteria ≥0.2…<2 μm (2…69%) and bacteria attached to small particles ≥2…<10 μm (27…93%) considerably surpassed that of bacteria associated with particles >10 μm (0…40%). This indicates that the larger particles and aggregates do not always contribute substantially to the overall microbial activity in rivers and estuaries.
The Situation of the German Elbe Tributaries — Development of the Loads in the Last 10 Years
Authors: Kowalik Corinna , Kraft Jörg , Einax Jürgen W.
Published: February 2004

From 1991 to 1996 intensive investigations (“Leitprojekt Elbe 2000”) were performed on the water and sediment quality of the German Elbe tributaries. Schwarze Elster, the Mulde river system (Freiberger Mulde, Zwickauer Mulde, andVereinigte Mulde), Saale and its tributaries Ilm and Unstrut, Weiße Elster, and Havel and Spree were considered. These important tributaries have a catchment area of approximately 86 000 km2 and they are together more than 2 500 km long.

The concentrations of different metals (e.g., Cd, Cr, Cu, Fe, Hg, Pb, or Zn) were determined. Furthermore, the alkali and alkaline earth elements and the concentrations of anions such as Cl—, NO, and SO were analyzed in the water samples. In addition, conductivity, pH, redox potential, and temperature were measured directly at the sampling location. Together 21 700 pieces of data for water samples and 8 300 pieces of data for sediment samples formed the base for the statistical evaluation and interpretation.

The water samples of the German Elbe tributaries are characterized by high salt loads (Ca, Mg, Na, Cl—, and conductivity), resulting from mining in the southern Harz region. In the sediments the concentrations of As, Cd, Pb, and Zn were identified as the most important anthropogenic parameters. The elements Co, Fe, Mn, and Ni were detected as typical background elements.
Saliva sampling to assess cortisol levels in unrestrained common marmosets and the effect of behavioral stress
Authors: Cross N. , Pines M.K. , Rogers L.J.
Published: February 2004

We report a method for taking saliva samples from unrestrained, captive marmosets (Callithrix jacchus) to assess levels of free cortisol. Saliva samples can be obtained reliably, without any habituation, by encouraging the marmosets to lick and chew a cotton‐wool bud coated in banana. Saliva is thus left on the bud. We also tested sweetened fruit‐drink crystals and a number of other substances, but none of these attracted all of the marmosets, and even flavors that were effective once soon lost their attraction. The presence of banana in the samples collected was found to lower the measured concentration of cortisol; however, as shown in samples taken with and without the banana coating on the bud, it did so in a linear and consistent way, and did not vary significantly among subjects. Therefore, a simple conversion factor could be applied to correct for the presence of banana. A first experiment showed that the marmosets exhibited a rise in salivary cortisol levels in response to social isolation. A second experiment showed elevation of cortisol during a period when the marmosets were disturbed by increased human activity and noise levels in the building in which they were housed. Hence, this method of saliva sampling is a convenient, noninvasive means of assessing cortisol levels in marmosets. Am. J. Primatol. 62:107–114, 2004. © 2004 Wiley‐Liss, Inc.
Predicting folivorous primate abundance: Validation of a nutritional model
Authors: Chapman Colin A. , Chapman Lauren J. , Naughton‐Treves Lisa , Lawes Michael J. , Mcdowell Lee R.
Published: February 2004

Understanding the determinants of animal abundance has become more vital as ecologists are increasingly asked to apply their knowledge to the construction of informed management plans. However, there are few general models are available to explain variation in abundance. Some notable exceptions are studies of folivorous primates, in which the protein‐to‐fiber ratio of foods has been shown to predict biomass. Here we examine the generality of Milton's [American Naturalist 114:363–378, 1979] protein/fiber model by providing a detailed analysis of diet selection in black‐and‐white colobus monkeys (Colobus guereza), and applying the model to populations shown to be stable; an assumption not previously examined. Based on observations of two groups of black‐and‐white colobus in Kibale National Park, Uganda, and one group in a forest fragment, we documented that the animals selected young leaves that had more protein, were more digestible, and had a higher protein‐to‐fiber ratio than mature leaves. The mature leaves did not differ from young leaves with respect to secondary compounds or mineral content (with the exceptions of copper and zinc). All of the colobus groups selected foods with a high protein‐to‐fiber ratios. However, one group also selected more digestible foods, and in another group, foraging efforts were positively related to zinc and negatively related to potassium. Previous studies that examined Milton's protein/fiber model did not demonstrate that the study populations were stable. If some populations were not at carrying capacity, then the correlations drawn between food availability and/or quality and folivore biomass may have been spurious. To address this issue, we censused a series of forest fragments in 1995 and again in 2000. We found that the populations in these fragments had declined from 165 in 1995 to 119 animals in 2000. However, based on evidence of population stability and lack of forest disturbance, we concluded that five of the original populations were stable. The biomass of these populations was related to the protein‐to‐fiber ratio of the fragment's trees. Combining our data with published data, we demonstrate that the protein‐to‐fiber ratios of mature leaves available to these folivorous primates accounted for 87% of the variance in their biomass. Am. J. Primatol. 62:55‐69, 2004. © 2004 Wiley‐Liss, Inc.
Dietary patterns in Perrier's sifakas (Propithecus diadema perrieri): A preliminary study
Authors: Lehman Shawn M. , Mayor Mireya
Published: February 2004

Some lemur species range into only one habitat type, whereas others range into a variety of habitats. Because plant community structure can differ between habitats, dietary patterns may vary for conspecific groups of primates that range into more than one type of habitat. The goal of our study was to determine how habitat variation influences dietary patterns in Perrier's sifakas (Propithecus diadema perrieri) that range into both dry and riparian forests in northern Madagascar. We collected 542 hr of data on the behavior and diet of two groups of P.d. perrieri from 7 June to 4 August 1998 at Camp Antobiratsy in Analamera Special Reserve, Madagascar. We computed indices of dietary diversity for each group and dietary/plant species similarity between groups. P.d. perrieri in group 1 fed predominantly in dry forest (72.7% of feeding records, n=660), whereas those in group 2 fed most often in riparian forest (73.7% of feeding records, n=666). The index of dietary similarity (0.986) was significantly higher than the index of plant species similarity (0.767). Although the P.d. perrieri in the two study groups fed predominantly in different forest habitats, they ate similar food items in very comparable proportions (but not from the same plant species). However, based on habitat availability measures, neither group fed where they were expected to feed. Am. J. Primatol. 62:115‐122, 2004. © 2004 Wiley‐Liss, Inc.
Prevalence of enteric parasites in pet macaques in Sulawesi, Indonesia
Authors: Jones‐Engel Lisa , Engel Gregory A. , Schillaci Michael A. , Froehlich Jeffery , Paputungan Umar , Kyes Randall C.
Published: February 2004

On the Indonesian island of Sulawesi, nonhuman primate pets come into frequent contact with humans, presenting the possibility of zoonotic and anthropozoonotic disease transmission. We collected fecal samples from 88 pet macaques representing six of the seven macaque species currently recognized as endemic to Sulawesi (Macaca nigra, M. nigrescens, M. hecki, M. tonkeana, M. maura, andM. ochreata) as well as two non‐endemic species (M. fascicularisandM. nemestrina) in order to determine the prevalence of intestinal parasitic infection in this population. Seven taxa of intestinal protozoa (Blastocystis hominis, Iodamoeba bütschlii, Entamoeba coli, Entamoeba hartmanni, Chilomastrix mesnili, Endolimax nana, andRetortamonas intestinalis) and three taxa of nematodes (hookworm,Trichurisspp., andAscarisspp.) were detected. The overall parasitization rate was 59.1%. Commensal organisms predominated in this population. Parasitization was not statistically correlated with macaque age group, sex, species, or location, or with the owner's level of education. These findings are discussed in the context of primate pet ownership practices in Sulawesi. Am. J. Primatol. 62:71‐82, 2004. © 2004 Wiley‐Liss, Inc.
Relations among birth condition, maternal condition, and postnatal growth in captive common marmoset monkeys (Callithrix jacchus)
Authors: Tardif Suzette D. , Bales Karen L.
Published: February 2004

The present study characterizes the relations among maternal condition, litter size, birth condition, and growth in body weight for a population of common marmosets. The subjects of the study were marmosets born into a single colony between 1994 and 2001. Three sets of analyses were conducted to answer the following questions: 1) Is there a relationship between litter size, maternal condition, and birth condition? In the study population, maternal body weight, maternal age, litter size, and birth condition were related in a complex fashion. Birth weight and prenatal long‐bone growth, as reflected in knee–heel length, were both related to maternal age, with older mothers supporting higher prenatal growth. Age and maternal condition appeared to interact as determinants of long‐bone growth, as the combination of older and larger mothers resulted in significantly longer knee–heel lengths in their offspring. 2) Is there a relationship between birth condition or maternal condition and subsequent growth or final adult size? The early growth rate in this population was similar to early growth rates reported for three different marmoset colonies, suggesting that early growth may be relatively inflexible in this species. However, within this population, the variation that did occur in early growth rate was related to birth weight and maternal weight. Later growth and adult weight were related to birth weight and litter size: small twin infants displayed slower later growth rates and were smaller as adults than twins that began life at a higher birth weight, while the birth weight of triplets was not related to adult size. In these marmosets, small infants that were the result of increased litter size differed from small infants whose small birth size resulted from other factors. This reinforces the proposal that the causes of low birth weight will be relevant to the development of the marmoset as a model of prenatal environmental effects. Am. J. Primatol. 62:83–94, 2004. © 2004 Wiley‐Liss, Inc.
Sexual behavior and hormonal estrus cycles in captive aged lowland gorillas (gorilla gorilla)
Authors: Atsalis Sylvia , Margulis Susan W. , Bellem Astrid , Wielebnowski Nadja
Published: February 2004

To evaluate whether observed cycles in proceptive behavior in aging lowland gorilla females (age 40+) at Brookfield Zoo were driven by ovarian activity, we compared monthly behavioral data to estradiol and progestogen cycles based on fecal hormone assessments. Progestogen peaks showed regularity and close coincidence with monthly sexual behaviors. Estradiol was more variable. Progestogen peaks varied between 22±5 days for the control female (29 years old), to 24±2.5 and 29±8 for the two aged subjects. In the first aged female, which was housed with other females and a silverback, the high degree of cyclicity in sexual behavior, regularity of progestogen cycles, and close concordance between hormonal cycling and sexual behavior strongly compared to patterns found (in this and other studies) in gorilla females <35 years old. Cyclical progestogen peaks were longer and more variable in the second aged female—perhaps because she lacked the social mediation of other females or a male. For husbandry reasons she is not housed with the gorilla group, behavioral data were not collected from her. The value of our longitudinal study is in obtaining reproductive profiles of primate females that are approaching maximum lifespan. This pilot study is part of a larger research project on reproductive senescence that will include other captive females >35 years old, a population that is rapidly increasing in North American zoos as gorillas continue to age. Am. J. Primatol. © 2004 Wiley‐Liss, Inc.