bluuebunny/crossref_metadata_2025 huggingface dataset:
SUMOylation modulates transcriptional repression by TRPS1
Authors: Kaiser Frank J. , Lüdecke Hermann-Josef , Weger Stefan
Published: March 2007

Mutations or deletions of the TRPS1 gene on human chromosome 8q.24.1 cause the tricho-rhino-phalangeal syndromes (TRPS), which are characterized by craniofacial and skeletal malformations. The gene encodes a transcription factor that functions as a repressor for GATA-mediated transcription. The activity of transcription factors is often controlled by posttranslational modifications. We show here that TRPS1 is SUMOylated at multiple sites, both in vivo and in vitro, through interaction with UBC9. Overexpression of wild-type UBC9 enhances TRPS1-mediated transcriptional repression. In contrast, a SUMOylation-deficient UBC9 mutant, which nevertheless still binds TRPS1, has no effect. Of the five potential TRPS1 SUMO-target sites, which were predicted based on a minimal SUMOylation consensus sequence (MCS), two are located within the C-terminal repression domain (RD) at lysine residues 1192 (termed S4) and 1201 (S5). S5 was identified as the major acceptor site within this region, and a point mutation of S5 strongly decreases TRPS1-RD-mediated transcriptional repression. Additional mutation of S4 results in abrogation of SUMOylation at the TRPS1-RD and almost complete loss of the repressive properties of TRPS1. These results identify SUMOylation at the TRPS1-RD as a major mechanism that regulates the function of TRPS1.
Cadherin-8 Is Required for the First Relay Synapses to Receive Functional Inputs from Primary Sensory Afferents for Cold Sensation
Authors: Suzuki Sachihiro C. , Furue Hidemasa , Koga Kohei , Jiang Nan , Nohmi Mitsuo , Shimazaki Yuka , Katoh-Fukui Yuko , Yokoyama Minesuke , Yoshimura Megumu , Takeichi Masatoshi
Published: March 2007

Classic cadherins, comprising multiple subtypes, mediate selective cell–cell adhesion based on their subtype-specific binding nature. Each subtype in the brain is expressed by restricted groups of functionally connected nuclei and laminas. However, whether each subtype has any specific role in neural circuitry remains largely unknown. Here, we show that cadherin-8 (cad8), a type-II classic cadherin, is important for cold sensation, whose circuitry is established by projection of sensory neurons into the spinal cord. Cad8 was expressed by a subset of neurons in the dorsal horn (DH) of the spinal cord, as well as by a small number of neurons in the dorsal root ganglia (DRGs), and the majority of cad8-positive DRG neurons coexpressed cold temperature/menthol receptor (TRPM8). We generatedcad8knock-out mice and analyzed lacZ markers expressed by the targetedcad8locus using heterozygous mice. LacZ/cad8-expressing sensory neurons and DH neurons were connected together, and cad8 protein was localized around the synaptic junctions formed between them. This relation was, however, not disrupted incad8−/− mice. We performed whole-cell patch-clamp recordings from DH neurons in spinal cord slices, in combination with menthol stimulation as a tool to excite central terminals of primary afferents expressing TRPM8. LacZ-expressing DH neurons exhibited fast and slow miniature EPSCs. Menthol selectively increased the frequency of the slow mEPSCs incad8+/− slices, but this effect was abolished incad8−/− slices. Thecad8−/− mice also showed a reduced sensitivity to cold temperature. These results demonstrate that cad8 is essential for establishing the physiological coupling between cold-sensitive sensory neurons and their target DH neurons.
Myelination of Congenitally Dysmyelinated Spinal Cord Axons by Adult Neural Precursor Cells Results in Formation of Nodes of Ranvier and Improved Axonal Conduction
Authors: Eftekharpour Eftekhar , Karimi-Abdolrezaee Soheila , Wang Jian , El Beheiry Hossam , Morshead Cindi , Fehlings Michael G.
Published: March 2007

Emerging evidence suggests that cell-based remyelination strategies may be a feasible therapeutic approach for CNS diseases characterized by myelin deficiency as a result of trauma, congenital anomalies, or diseases. Although experimental demyelination models targeted at the transient elimination of oligodendrocytes have suggested that transplantation-based remyelination can partially restore axonal molecular structure and function, it is not clear whether such therapeutic approaches can be used to achieve functional remyelination in models associated with long-term, irreversible myelin deficiency. In this study, we transplanted adult neural precursor cells (aNPCs) from the brain of adult transgenic mice into the spinal cords of adultShiverer(shi/shi) mice, which lack compact CNS myelin. Six weeks after transplantation, the transplanted aNPCs expressed oligodendrocyte markers, including MBP, migrated extensively along the white matter tracts of the spinal cord, and formed compact myelin. Conventional and three-dimensional confocal and electron microscopy revealed axonal ensheathment, establishment of paranodal junctional complexes leading tode novoformation of nodes of Ranvier, and partial reconstruction of the juxtaparanodal and paranodal molecular regions of axons based on Kv1.2 and Caspr (contactin-associated protein) expression by the transplanted aNPCs. Electrophysiological recordings revealed improved axonal conduction along the transplanted segments of spinal cords. We conclude that myelination of congenitally dysmyelinated adult CNS axons by grafted aNPCs results in the formation of compact myelin, reconstruction of nodes of Ranvier, and enhanced axonal conduction. These data suggest the therapeutic potential of aNPCs to promote functionally significant myelination in CNS disorders characterized by longstanding myelin deficiency.
Independent Functions of Slit–Robo Repulsion and Netrin–Frazzled Attraction Regulate Axon Crossing at the Midline inDrosophila
Authors: Garbe David S. , Bashaw Greg J.
Published: March 2007

Slit and Netrin and their respective neuronal receptors play critical roles in patterning axonal connections in the developing nervous system by regulating the decision of whether or not to cross the midline. Studies of both invertebrate and vertebrate systems support the idea that Netrin, secreted by midline cells, signals through DCC (Deleted in Colorectal Carcinoma)/UNC40/Frazzled receptors to attract commissural axons toward and across the midline, whereas Slit signals through Robo family receptors to prevent commissural axons from recrossing the midline, as well as to prevent ipsilateral axons from ever crossing. Recent evidence from bothXenopusneuronal cell culture andDrosophilagenetics have suggested that these signals may interact more directly in a hierarchical relationship, such that one response extinguishes the other. Here we present loss- and gain-of-function genetic evidence showing that the influence of Slit and Netrin on midline axon crossing is dictated by both independent and interdependent signaling functions of the Robo and Frazzled (Fra) receptors. Our results are not consistent with the proposal based on genetic analysis inDrosophilathat the sole function of Slit and Robo during midline guidance is to repress Netrin attraction.
From Hunger to Satiety: Reconfiguration of a Feeding Network byAplysiaNeuropeptide Y
Authors: Jing Jian , Vilim Ferdinand S. , Horn Charles C. , Alexeeva Vera , Hatcher Nathan G. , Sasaki Kosei , Yashina Irene , Zhurov Yuriy , Kupfermann Irving , Sweedler Jonathan V. , Weiss Klaudiusz R.
Published: March 2007

A shift in motivational state often produces behavioral change, but the underlying mechanisms are poorly understood. In the marine mollusc,Aplysia californica, feeding-induced transition from a hunger to satiation state leads to a slowdown and an eventual termination of feeding. Because the multifunctional feeding network generates both ingestion and the competing response, egestion, it is possible that the transition from a hunger to a satiety state is associated with network reconfiguration that results in production of fewer ingestive and more egestive responses. Chronic electrophysiological recordings in free-feedingAplysiashowed that as the meal progressed, food elicited fewer ingestive responses and simultaneously increased the number of egestive responses. Injections ofAplysianeuropeptide Y (apNPY) reduced food intake and slowed down the rate of ingestion. apNPY was localized to buccal-ganglion afferents originating in the gut-innervating esophageal nerve (EN), a nerve involved both in satiation and in the generation of egestive programs. During EN stimulation, apNPY was released in the feeding circuit. Importantly, stimulation of the cerebral-buccal interneuron-2, a command-like interneuron that is activated by food and normally elicits ingestive responses, elicited egestive responses in the presence of apNPY. This was accompanied by increased activity of the egestion-promoting interneuron B20 and decreased activity in the ingestion-promoting interneuron B40. Thus, apNPYergic reconfiguration of the feeding central pattern generator plays a role in the gradual transition from hunger to satiety states. More generally, changes in the motivational states may involve not only simple network inhibition but may also require network reconfiguration.
Afferent Control of Horizontal Cell Morphology Revealed by Genetic Respecification of Rods and Cones
Authors: Raven Mary A. , Oh Edwin C. T. , Swaroop Anand , Reese Benjamin E.
Published: March 2007

The first inhibitory interneurons of the retina, the horizontal cells, stratify within the outer plexiform layer, extending dendritic terminals that connect to the pedicles of cone photoreceptors and an axon terminal system contacting the spherules of rod photoreceptors. How the horizontal cells acquire this morphology is unknown, but instructive interactions with afferents are suggested to play a role in the development of synaptic circuits. Here, we show that the morphology of the axon terminal system and the dendritic field are selectively regulated by innervation from their respective afferents: genetic respecification of all cones to become rods, inCrxp-Nrltransgenic mice, produces an atrophic dendritic field yet leaves the axon terminal system largely intact. In contrast, in the retinas ofNrl−/−mice, in which the population of rod photoreceptors is respecified to adopt a cone fate, the dendritic field is hypertrophic, whereas the axon terminal system is underdeveloped. Our studies reveal that, although cell-intrinsic mechanisms drive the formation of independent dendritic versus axonal domains, the afferents play a selectively instructive role in defining their respective morphologies.
Cocaine-Associated Stimuli Increase Cocaine Seeking and Activate Accumbens Core Neurons after Abstinence
Authors: Hollander Jonathan A. , Carelli Regina M.
Published: March 2007

Electrophysiological recordings were completed in rats (n= 14) trained to self-administer cocaine to determine whether activation of nucleus accumbens (Acb) neurons (core vs shell) by cocaine-associated stimuli is enhanced after 1 month of cocaine abstinence. After self-administration training, 170 cells were recorded during a single test session conducted either the next day or 1 month later. The test session consisted of three phases during which (1) the cocaine cue was presented unexpectedly to rats, (2) rats responded for the same cue in the absence of the drug (extinction), and (3) the cocaine cue was presented randomly between cocaine-reinforced responding during resumption of self-administration. The cocaine stimulus significantly increased activation of Acb core (not shell) neurons after 1 month of cocaine abstinence (compared with 1 d); this finding occurred regardless of contingency of cue presentation or cocaine availability. Acb core activation was not observed in other rats (n= 7) presented with the same stimulus never paired with cocaine. The results reflect a cellular neuroadaptation in the Acb core related to cocaine-associated cues that is observed during initial cue exposure and sustained during extinction and resumption of self-administration after prolonged drug abstinence.
Functional Coupling of Human Prefrontal and Premotor Areas during Cognitive Manipulation
Authors: Abe Mitsunari , Hanakawa Takashi , Takayama Yoshihiro , Kuroki Chihiro , Ogawa Seiji , Fukuyama Hidenao
Published: March 2007

Evidence indicates the involvement of the rostral part of the dorsal premotor cortex (pre-PMd) in executive processes during working memory tasks. However, it remains unclear what the executive function of pre-PMd is in relation to that of the dorsolateral prefrontal cortex (DLPFC) and how these two areas interact. Using functional magnetic resonance imaging (fMRI), brain activity was examined during a delayed-encoding recognition task. Fifteen subjects had prelearned several four-code standard sequences and super sequences (SUPs) consisting of a train of two standard sequences to form “chunks” in long-term memory. During fMRI, subjects remembered eight-code encoding stimuli presented as an SUP or two unlinked standard sequences (2STs). A memory probe prompted the subjects to recognize codes across two chunks (ACROSS) or within a single chunk. A 2 × 2 factorial design was used to test two types of working memory manipulation: (1) a reductive operation selecting codes from chunks (“segmenting”) and (2) a synthetic operation converting unlinked codes into a sequence (“binding”). Response time data supported the behavioral effects of each operation. Event-related fMRI showed that the “segmenting operation” activated the DLPFC bilaterally, whereas the “binding operation” enhanced the left pre-PMd activity. Activity in the ventrolateral prefrontal cortex suggested its involvement in the retrieval of task-relevant information from long-term memory. Furthermore, effective connectivity analysis indicated that the left pre-PMd and ipsilateral DLPFC interacted specifically during the ACROSS recognition of 2STs, the condition that involved both operations. We propose specific neural substrates for working memory manipulation: the DLPFC for segmenting/attentional selection and the pre-PMd for binding/sequencing. The functional coupling between the DLPFC and pre-PMd appears to play a role in combining these distinct operations.
Phospholipase C Is Required for Changes in Postsynaptic Structure and Function Associated with NMDA Receptor-Dependent Long-Term Depression
Authors: Horne Eric A. , Dell'Acqua Mark L.
Published: March 2007

NMDA receptor (NMDAR)-dependent hippocampal synaptic plasticity underlying learning and memory coordinately regulates dendritic spine structure and AMPA receptor (AMPAR) postsynaptic strength through poorly understood mechanisms. Induction of long-term depression (LTD) activates protein phosphatase 2B/calcineurin (CaN), leading to dendritic spine shrinkage through actin depolymerization and AMPAR depression through receptor dephosphorylation and internalization. The scaffold proteins A-kinase-anchoring protein 79/150 (AKAP79/150) and postsynaptic density 95 (PSD95) form a complex that controls the opposing actions of the cAMP-dependent protein kinase (PKA) and CaN in regulation of AMPAR phosphorylation. The AKAP79/150–PSD95 complex is disrupted in hippocampal neurons during LTD coincident with internalization of AMPARs, decreases in PSD95 levels, and loss of AKAP79/150 and PKA from spines. AKAP79/150 is targeted to spines through binding F-actin and the phospholipid phosphatidylinositol-(4,5)-bisphosphate (PIP2). Previous electrophysiological studies have demonstrated that inhibition of phospholipase C (PLC)-catalyzed hydrolysis of PIP2inhibits NMDAR-dependent LTD; however, the signaling mechanisms that link PLC activation to alterations in dendritic spine structure and AMPAR function in LTD are unknown. We show here that NMDAR stimulation of PLC in cultured hippocampal neurons is necessary for AKAP79/150 loss from spines and depolymerization of spine actin. Importantly, we demonstrate that NMDAR activation of PLC is also necessary for decreases in spine PSD95 levels and AMPAR internalization. Thus, PLC signaling is required for structural and functional changes in spine actin, PSD scaffolding, and AMPAR trafficking underlying postsynaptic expression of LTD.
Ethanol Induces Long-Term Facilitation of NR2B-NMDA Receptor Activity in the Dorsal Striatum: Implications for Alcohol Drinking Behavior
Authors: Wang Jun , Carnicella Sebastien , Phamluong Khanhky , Jeanblanc Jerome , Ronesi Jennifer A. , Chaudhri Nadia , Janak Patricia H. , Lovinger David M. , Ron Dorit
Published: March 2007

Addiction is characterized by compulsive alcohol or drug taking and seeking, and the dorsal striatum has been implicated in such maladaptive persistent habits. The NMDA receptor (NMDAR), which is a major target of alcohol, is implicated in striatal-based habit learning. We found that, in the dorsal striatum, alcohol (ethanol) exposure produced an increase in the phosphorylation of the NR2B subunit of the NMDAR, and a corresponding increase in the activity of Fyn kinase, which phosphorylates NR2B. We further observed an ethanol-mediated long-term facilitation (LTF) of the activity of NR2B-containing NMDARs (NR2B-NMDARs) in the dorsal striatum. This LTF is Fyn kinase dependent, because it was observed in Fyn wild-type but not in Fyn knock-out mice. Importantly, none of these biochemical and physiological changes was observed in the ventral striatum. Finally, dorsal but not ventral striatum infusion of a Fyn or NR2B-NMDAR inhibitor reduced rat operant self-administration of ethanol. Our results suggest that the Fyn-mediated phosphorylation and LTF of NR2B-NMDAR activity in the dorsal striatum after exposure to ethanol may underlie aberrant plasticity that contributes to mechanisms underlying alcohol drinking behavior.
Biphasic Coupling of Neuronal Nitric Oxide Synthase Phosphorylation to the NMDA Receptor Regulates AMPA Receptor Trafficking and Neuronal Cell Death
Authors: Rameau Gerald A. , Tukey David S. , Garcin-Hosfield Elsa D. , Titcombe Roseann F. , Misra Charu , Khatri Latika , Getzoff Elizabeth D. , Ziff Edward B.
Published: March 2007

Postsynaptic nitric oxide (NO) production affects synaptic plasticity and neuronal cell death. Ca2+fluxes through the NMDA receptor (NMDAR) stimulate the production of NO by neuronal nitric oxide synthase (nNOS). However, the mechanisms by which nNOS activity is regulated are poorly understood. We evaluated the effect of neuronal stimulation with glutamate on the phosphorylation of nNOS. We show that, in cortical neurons, a low glutamate concentration (30 μm) induces rapid and transient NMDAR-dependent phosphorylation of S1412 by Akt, followed by sustained phosphorylation of S847 by CaMKII (calcium-calmodulin-dependent kinase II). We demonstrate that phosphorylation of S1412 by Akt is necessary for activation of nNOS by the NMDAR. nNOS mutagenesis confirms that these phosphorylations respectively activate and inhibit nNOS and, thus, transiently activate NO production. A constitutively active (S1412D), but not a constitutively repressed (S847D) nNOS mutant elevated surface glutamate receptor 2 levels, demonstrating that these phosphorylations can control AMPA receptor trafficking via NO. Notably, an excitotoxic stimulus (150 μmglutamate) induced S1412, but not S847 phosphorylation, leading to deregulated nNOS activation. S1412D did not kill neurons; however, it enhanced the excitotoxicity of a concomitant glutamate stimulus. We propose a swinging domain model for the regulation of nNOS: S1412 phosphorylation facilitates electron flow within the reductase module of nNOS, increasing nNOS sensitivity to Ca2+-calmodulin. These findings suggest a critical role for a kinetically complex and novel series of regulatory nNOS phosphorylations induced by the NMDA receptor for thein vivocontrol of nNOS.
Osteopontin-Deficient Mice Exhibit Less Inflammation, Greater Tissue Damage, and Impaired Locomotor Recovery from Spinal Cord Injury Compared with Wild-Type Controls
Authors: Hashimoto Masayuki , Sun Dongming , Rittling Susan R. , Denhardt David T. , Young Wise
Published: March 2007

Osteopontin (OPN) is expressed in many tissues during inflammatory responses. After spinal cord injury, microglia expresses OPN at the site of injury during the early to subacute stages. However, the function of OPN in spinal cord injury is not well understood. This study examines the responses of OPN knock-out (KO) and wild-type (WT) mice to spinal cord contusion injury. KO and WT mice were injured with a modified New York University impactor. Weights of 10 or 5.6 g were dropped 6.25 mm onto the T13 spinal cord under isoflurane anesthesia. At 24 h, homogenized spinal cords were analyzed for total potassium concentration to estimate lesion volumes. Expression of apoptotic genes, proinflammatory cytokines, and nerve growth factors was measured by reverse transcription (RT)-PCR and Western blot. In a series of animals, locomotor recovery was assessed with the Basso mouse scale (BMS) for 6 weeks, and histological analyses was performed to determine tissue preservation. Lesion volume showed no significant differences between KO and WT mice at 24 h. RT-PCR indicated that KO mice had significantly less Bcl-2, tumor necrosis factor-α, interleukin-1β, and interleukin-6 mRNA compared with WT controls. Western blot also showed that KO had significantly less Bcl-2 7 d after spinal cord injury. KO mice had significantly worse BMS locomotor scores than WT at 6 weeks. KO mice also had a significantly reduced area of spared white matter and fewer neuronal-specific nuclear protein-positive neurons in the spinal cord surrounding the impact site. This result supports a potential neuroprotective role for OPN in the inflammatory response to spinal cord injury.
An NMDA Receptor/Nitric Oxide Cascade in Presynaptic Parallel Fiber–Purkinje Neuron Long-Term Potentiation
Authors: Qiu De-lai , Knöpfel Thomas
Published: March 2007

Plasticity of synaptic transmission between parallel fiber (PF) and Purkinje neurons (PNs) is widely accepted as a cellular model for certain forms of cerebellar learning. Whereas the signaling cascades involved in postsynaptically expressed bidirectional long-term changes at PF–PN synapses are well investigated, data on presynaptically expressed long-term potentiation (LTP) are incomplete and controversial. Here we used transgenic mice that express a fluorescent protein Ca2+sensor in PFs to demonstrate LTP of PF presynaptic Ca2+transients after PF stimulation with 120 pulses at 4 Hz. Potentiation of the presynaptic Ca2+transients correlated with the expression of simultaneously recorded LTP of PF–PN synaptic transmission and was suppressed by a protein kinase A inhibitor. Moreover, this presynaptically expressed form of LTP clearly required activation of an NMDA receptor/nitric oxide pathway, in contrast with the majority of previous reports. Blockade of NMDA receptors did not affect the PF Ca2+transients induced during 4 Hz stimulation, indicating that the NMDA receptors required for the induction of presynaptic PF LTP are not localized in PFs.
Rho Regulates Membrane Transport in the Endocytic Pathway to Control Plasma Membrane Specialization in Oligodendroglial Cells
Authors: Kippert Angelika , Trajkovic Katarina , Rajendran Lawrence , Ries Jonas , Simons Mikael
Published: March 2007

Differentiation of oligodendrocytes is associated with dramatic changes in plasma membrane structure, culminating in the formation of myelin membrane sheaths. Previous results have provided evidence that regulation of endocytosis may represent a mechanism to control myelin membrane growth. Immature oligodendrocytes have a high rate of clathrin-independent endocytosis for the transport of membrane to late endosomes/lysosomes (LE/Ls). After maturation and receiving signals from neurons, endocytosis is reduced and transport of membrane from LE/Ls to the plasma membrane is triggered. Here, we show that changes in Rho GTPase activity are responsible for switching between these two modes of membrane transport. Strikingly, Rho inactivation did not only reduce the transport of cargo to LE/L but also increased the dynamics of LE/L vesicles. Furthermore, we provide evidence that Rho inactivation results in the condensation of the plasma membrane in a polarized manner. In summary, our data reveal a novel role of Rho: to regulate the flow of membrane and to promote changes in cell surface structure and polarity in oligodendroglial cells. We suggest that Rho inactivation is required to trigger plasma membrane specialization in oligodendrocytes.
Nicotine Enhances Visuospatial Attention by Deactivating Areas of the Resting Brain Default Network
Authors: Hahn Britta , Ross Thomas J. , Yang Yihong , Kim Insook , Huestis Marilyn A. , Stein Elliot A.
Published: March 2007

Nicotine-induced attentional enhancement is of potential therapeutic value. To investigate the precise attentional function(s) affected and their neuronal mechanisms, the current functional magnetic resonance imaging (fMRI) study used an attention task in which subjects responded to stimuli of high (INThigh) or low intensity presented randomly in one of four peripheral locations. Central cues of varying precision predicted the target location. In some trials, the cue was not followed by a target, allowing separate analysis of blood oxygenation level-dependent (BOLD) responses to cue. Minimally deprived smokers underwent fast event-related fMRI twice: once with a nicotine patch (21 mg) and once with a placebo patch. Matched nonsmokers were scanned twice without a patch. Behaviorally, nicotine reduced omission errors and reaction time (RT) of valid and invalid cue trials and intra-individual variability of RT and did so preferentially in trials with INThigh. The BOLD signal related to cue-only trials, regardless of cue precision, demonstrated nicotine-induced deactivation in anterior and posterior cingulate, angular gyrus, middle frontal gyrus, and cuneus. These regions overlapped with the so-called “default network,” which activates during rest and deactivates with attention-demanding activities. Partial correlations controlling for nicotine plasma levels indicated associations of deactivation by nicotine in posterior cingulate and angular gyrus with performance improvements under INThigh. Performance and regional activity in the absence of nicotine never differed between smokers and nonsmokers, ruling out a simple reversal of a deprivation-induced state. These findings suggest that nicotine improved attentional performance by downregulating resting brain function in response to task-related cues. Together with the selectivity of effects for INThigh, this suggests a nicotine-induced potentiation of the alerting properties of external stimuli.
Absence of Normal Photic Integration in the Circadian Visual System: Response to Millisecond Light Flashes
Authors: Vidal Luis , Morin Lawrence P.
Published: March 2007

Light is the most prominent synchronizing stimulus for circadian rhythms. The circadian visual system responds in accordance with the energy content of photic stimuli longer than a few seconds. Here, as few as three flashes (2 ms each delivered to hamsters over 5 or 60 min at circadian time 19) elicited large phase advances. Ten or more flashes were required to induce FOS protein in the suprachiasmatic nucleus (SCN), and such induction occurred throughout the entire SCN, as well as outside the nucleus. High-density flash stimulation (0.5 s interflash interval) was ineffective, but response increased as the interval increased up to 4 s. In an irradiance response test, phase shifts appeared to be all-or-none with threshold irradiance between 140 and 1070 μW/cm2, implying lack of stimulus energy summation. Nevertheless, an irradiance ineffective when delivered as 10 flashes induced phase shifts when given as100 flashes, but the response was substantially smaller than elicited by 10 flashes, each with ∼1 log unit more irradiance. The results also show reduced sensitivity of flash-induced FOS response in the intergeniculate leaflet compared with the SCN, contrary to studies using longer light stimuli. Masking was robust and prolonged in response to 10 flashes. The data demonstrate that the circadian visual system responds markedly to brief, intense light stimuli without normal photic integration. This may involve a second input pathway different from that mediating the effects of longer, dimmer photic stimuli.
Digital Rights Management und allgegenwärtiges Rechnen (Digital Rights Management and Ubiquitous Computing)
Authors: Peukert Alexander
Published: March 2007

Digitales Rechtemanagement wird unter anderem zum technisch gesteuerten Vertrieb urheberrechtlich geschützter Inhalte eingesetzt. Seit 10 Jahren existieren Vorschriften, die die Umgehung derartiger technischer Maßnahmen verbieten. Der Beitrag erläutert den Interessenkonflikt, der diesen Normen zugrunde liegt, den wesentlichen Inhalt der Vorschriften und aktuelle Problemfelder des Rechtsschutzes von DRM.
Technische Dokumentation von Soft- und Hardware in Eingebetteten Systemen (Technical Documentation of Soft- and Hardware in Embedded Systems)
Authors: Muranko Beate , Drechsler Rolf
Published: March 2007

Eingebettete Systeme sind dadurch charakterisiert, dass sie Soft- und Hardwarekomponenten beinhalten. Diese Systeme sind integriert in Produkten wie Handys, Kameras, Fernseher, Autos usw. Aufgrund der Größe von Eingebetteten Systemen und der Wiederverwendung der einzelnen Komponenten erlangt die Dokumentation der Komponenten eine immer größere Bedeutung. Obwohl die Bedeutung der Dokumentation über Jahre gewachsen ist, ist es immer noch ein vernachlässigter Bereich im Entwicklungsprozess. In dieser Arbeit wird die Integration der technischen Dokumentation in Soft- und Hardwareentwicklungsprozessen diskutiert. Hierfür werden klassische Soft- und Hardwareentwicklungsmodelle bezüglich der technischen Dokumentation analysiert und evaluiert. Ferner wird ein aus der Praxis abgeleiteter Dokumentationsablauf vorgestellt, welcher in vorhandene Soft- und Hardwareentwicklungsmodelle integriert werden kann. Diese Arbeit zeigt einen Ansatz zur Integration des Dokumentationsablaufs in ein Entwicklungsmodell.
SFB/TR 14 AVACS – Automatic Verification and Analysis of Complex Systems (Der Sonderforschungsbereich/Transregio 14 AVACS – Automatische Verifikation und Analyse komplexer Systeme)
Authors: Becker Bernd , Podelski Andreas , Damm Werner , Fränzle Martin , Olderog Ernst-Rüdiger , Wilhelm Reinhard
Published: March 2007

The Transregional Collaborative Research Center AVACS integrates the three sites Freiburg, Oldenburg, and Saarbrücken, and addresses the challenge of pushing the borderline for automatic verification and analysis of complex systems. A particular focus of the project is on models of complex transportation systems and their safety requirements. AVACS is organized in ten subprojects, each teaming researchers from all sites, and is funded by the German Science Foundation since January 1, 2004. This article surveys scope, organization, and research directions of AVACS, including pointers to key publications.
Computers and Law: Some beginnings (Computer und Recht – Die Anfänge)
Authors: Bing Jon
Published: March 2007

In the late 1960s computers and computer applications also caught the attention of lawyers. The phrase “computers and law” was coined. In the beginning, research took two somewhat different directions. One direction looked to computer technology to support legal research through information systems, through the computerisation of public administration, and through reform of systems for the administration of justice. The other direction was concerned with the issues of substantial law and the social consequences of computerisation. In the following contribution by Bing, who is one of the early researchers in Northern Europe from these first days, and who has contributed to its theory and practice, sketches the development of this interface between law and information technology, which today is known under many names, perhaps most commonly “law and information technology”, “cyberlaw”, “information law” etc., and a few of its beginnings in research and methods.
Datenschutz in der Welt allgegenwärtigen Rechnens (Privacy in a World of Ubiquitous Computing)
Authors: Rossnagel Alexander
Published: March 2007

Die allgegenwärtige Verarbeitung personenbezogener Daten wird nicht nur neue Missbrauchsmöglichkeiten bieten, sondern zentrale Grundlagen des Datenschutzrechts in Frage stellen. Sie verursacht nicht nur ein Vollzugs-, sondern ein grundlegendes Konzeptproblem. Aber auch in dieser Welt bleibt eine gesellschaftliche Kommunikation, die auf informationeller Selbstbestimmung beruht, unverzichtbar. Bedingung informationeller Selbstbestimmung ist jedoch ein grundsätzlich modifiziertes Schutzprogramm des Datenschutzrechts, das der gesellschaftsumwälzenden Kraft des allgegenwärtigen Rechnens gerecht wird.
Solubility and redox reactions of Pu(IV) hydrous oxide: Evidence for the formation of PuO2+x(s, hyd)
Authors: Neck Volker , Altmaier M. , Seibert A. , Yun J. I. , Marquardt Christian M. , Fanghänel Thomas
Published: March 2007

The solubility and redox reactions of Pu(IV) hydrous oxide were analyzed by comparing total Pu concentrations, oxidation state distributions and simultaneously measured redox potentials under air and under Ar containing only traces of oxygen. At pH>3 the aqueous Pu concentration is dominated by Pu(V) for both solubility studies under air and argon. Combining all information strongly indicates that PuO2+x(s,hyd), mixed valent (PuV)2x(PuIV)1-2xO2+x(s,hyd) or (PuO2.5)2x(PuO2)1-2x(s,hyd) withx= 0.003 (present study) andx= 0.05–0.06 (literature studies under air), is the solubility controlling solid phase. It can be formed by the oxidation of PuO2(s,hyd) with the oxygen in the system and by co-precipitation of Pu(V) and Pu(IV). The Pu4+concentration is given by the known solubility product of Pu(IV) hydrous oxide and the PuO2+concentration is described by the solubility product (Ksp= [PuO2+][OH-]) for the fraction of Pu(V) in PuO2+x(s,hyd): logK°sp= −14.0±0.8 at zero ionic strength. Small Pu(IV) colloids/polymers present in neutral to alkaline solutions at a constant level of log[Pu(IV)]coll= −8.3±1.0 play an important role for the redox potentials in these systems. Similar Pu(V) concentrations and redox potentials were reached from oversaturation in initially Pu(VI) solutions.
Properties of U(VI)/U(IV) and Fe(III)/Fe(II) pairs and equilibrium U(VI) + 2Fe(II) ⇄ U(IV) + 2Fe(III) in solutions of unsaturated heteropolytungstates K10P2W17O61 and K8SiW11O39
Authors: Yusov A. B. , Shilov V. P. , Fedosseev A. M. , Moisy Ph.
Published: March 2007

The unsaturated phosphotungstate K10P2W17O61 and silicotungstate K8SiW11O39 are strong and selective complexants of An(IV) in aqueous solution. In presence of these complexants, the redox properties of actinides are changed drastically due to stabilization of the tetravalent actinides.

Redox potentials of Fe(III)/Fe(II) and U(VI)/U(IV) pairs were measured in K10P2W17O61 and K8SiW11O39, solutions with various HClO4 concentration and absolute complexes stability constants of Fe(III) ions with phosphotungstate and silicotungstate ions were determined: logβabs
Fe(III)=17.4 ± 0.8 and 20.1 ± 0.8 respectively. The equilibrium constant of reaction between U(VI) and Fe(II) in 1 M HClO4 was determined. The equilibrium constant, K
eq, depends on excess of heteropolyanion, and is close to 104 in 1 M HClO4 at [P2W17O61]free ∼ 5 × 10-4 M.
Preparation and characterization of working standards for 238Pu
Authors: Aggarwal S. K. , Shah P. M. , Alamelu D. , Mirashi N. N.
Published: March 2007

An attempt is made to prepare and characterize the working standards of 238Pu by mixing solutions of enriched isotopes of 238Pu and 239Pu, available indigenously. The working standards were characterized using the recently developed interfering element correction methodology in thermal ionization mass spectrometry (TIMS) and the data were compared with those obtained by conventionally used alpha spectrometry. The results obtained by alpha spectrometry on various synthetic mixtures agreed within 0.5 to 1% to those determined by TIMS. These studies show that by mixing accurately weighable amounts of highly enriched 238Pu and 239Pu isotopes, it is possible to prepare and characterize the certified reference materials (CRMs) for 238Pu, which have eluded the nuclear community until recently. The commercial availability of these CRMs would allow the traceability of 238Pu measurements in Pu using different radio-analytical techniques, provide a common platform to the measurements made on 238Pu by various nuclear material accounting laboratories around the world, and would also permit the use of newly developed TIMS methodology, by various laboratories, with confidence.
Trace element intake and dietary status of nuts consumed in Pakistan: study using INAA
Authors: Waheed Shahida , Siddique N. , Rahman A.
Published: March 2007

Five nuts, namely almond, cashew nuts, peanuts, pine nuts and pistachio, commonly consumed in Pakistan, were analyzed for their inorganic element contents. Instrumental neutron activation analysis (INAA) methodology, using different irradiation, cooling and counting protocols, was adopted to determine Al, Br, Ca, Cl, Co, Cs, Eu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Rb, Sc, Se, Sr and Zn. The investigated nuts were found to contain substantial amounts of Ca, Cl, Fe, Mg, K, Na and Zn. Dietary intake of the essential inorganic elements present in these nuts, as compared to the recommended dietary allowance, has also been calculated. This has further substantiated the nutrient role of nuts in the prevention of cardiovascular disease, as in addition to their established efficacy in improving the lipid profile, they are a rich source of cardioprotective trace elements such as magnesium, zinc, iron and calcium. Toxic elements were present in very low concentrations in nuts.
Kitchen Conversations: Democracy in Action at the Lower East Side Tenement Museum
Authors: ABRAM RUTH J.
Published: March 2007

This article describes the Lower East Side Tenement Museum's ongoing public dialogue on immigration, the first in the United States. As she joins facilitators in reflecting on the importance of dialogue in a democracy, museum president Ruth J. Abram explains how and why the program was initiated, the obstacles that had to be overcome, and the public reaction to it. Kitchen Conversations represents the museum's commitment to the proposition that historic sites must function as places of civic engagement, using the history they interpret as a starting place for dialogue on related contemporary issues.
Removal of colour from a kraft pulp and paper mill effluent in Kenya using a combination of electrochemical method and phosphate rock
Authors: Etiégni L. , Oricho O.D. , Ofosu-Asiedu K. , Senelwa K.A. , Surtan K.G. , Omutange E.S.
Published: March 2007

A study was undertaken to remove colour from a kraft mill's treated effluent in Kenya and determine the suitability of phosphate rock to replace wood ash during the electrochemical process. The electrochemical method alone, electrochemical combined with alum (ELCAL), wood ash leachate (ELCAS) and phosphate rock (ELPHOS) solutions at a rate of 165 to 1,000 g/m3 were tested. Effluent characteristics were determined after complete removal of colour. Same reduction rates of TS (85%) and TSS (89%) were recorded by ELCAS and ELPHOS. However, ELPHOS removed more COD (86 to 91%) and more BOD (85 to 92%) than ELCAS. Furthermore, the pH of ELPHOS treated solution was 9.3, within the Kenya Local Government's allowable limit. Power reduction with ELCAS and ELPHOS varied between 53 to 73% and 49 to 69% respectively but the difference was not statistically significant. Overnight aeration further improved the quality of ELCAS and ELPHOS treated effluent, reducing BOD and COD values to 0 mg/l. ELPHOS cost ($0.29/m3) was nevertheless three times higher than that of ELCAS ($0.10/m3), mainly because of free wood ash. ELPHOS did not also increase effluent phosphorus. It was therefore recommended that various ways be explored in making ELPHOS more economical to replace ELCAS.
Comparative study of MBR and activated sludge in the treatment of paper mill wastewater
Authors: Lerner M. , Stahl N. , Galil N.I.
Published: March 2007

The study was based on a full scale activated sludge plant (AS) compared to a parallel operated pilot membrane bioreactor (MBR) with flat sheets membranes. Both systems received their influent from an anaerobic bioreactor treating paper mill wastewater. MBR produced an effluent of much better quality than AS in terms of suspended solids, containing 1 mg/L or less in 80% of the monitoring time, while the AS effluent contained 12 mg/L. This could save the necessity of further treatment by filtration in the case of MBR. Other effluent quality parameters, such as organic matter (COD and BOD), phosphorus and ammonia nitrogen, did not indicate substantial differences between AS and MBR. Calcium carbonate scaling and formation of a bacterial layer on the membrane caused severe flux reduction. The membrane blockage because of scaling and biofouling proved to be very serious, therefore, it required proper and more complicated maintenance than the AS system. This study leads to the conclusion that in the case of paper mill wastewater, after anaerobic biotreatment, if there is no need for excellent effluent quality in terms of suspended solids, the replacement of the AS by the MBR would not be strongly justified, mainly because of maintenance cost.
Effect of hot acid hydrolysis and hot chlorine dioxide stage on bleaching effluent biodegradability
Authors: Gomes C.M. , Colodette J.L. , Delantonio N.R.N. , Mounteer A.H. , Silva C.M.
Published: March 2007

The hot acid hydrolysis followed by chlorine dioxide (A/D*) and hot chlorine dioxide (D*) technologies have proven very useful for bleaching of eucalyptus kraft pulp. Although the characteristics and biodegradability of effluents from conventional chlorine dioxide bleaching are well known, such information is not yet available for effluents derived from hot acid hydrolysis and hot chorine dioxide bleaching. This study discusses the characteristics and biodegradability of such effluents. Combined whole effluents from the complete sequences DEpD, D*EpD, A/D*EpD and ADEpD, and from the pre-bleaching sequences DEp, D*Ep, A/D*Ep and ADEp were characterized by quantifying their colour, AOX and organic load (BOD, COD, TOC). These effluents were also evaluated for their treatability by simulation of an activated sludge system. It was concluded that treatment in the laboratory sequencing batch reactor was efficient for removal of COD, BOD and TOC of all effluents. However, colour increased after biological treatment, with the greatest increase found for the effluent produced using the AD technology. Biological treatment was less efficient at removing AOX of effluents from the sequences with D*, A/D* and AD as the first stages, when compared to the reference D stage; there was evidence of the lower treatability of these organochlorine compounds from these sequences.
Multivariate statistical analysis of a high rate biofilm process treating kraft mill bleach plant effluent
Authors: Goode C. , LeRoy J. , Allen D.G.
Published: March 2007

This study reports on a multivariate analysis of the moving bed biofilm reactor (MBBR) wastewater treatment system at a Canadian pulp mill. The modelling approach involved a data overview by principal component analysis (PCA) followed by partial least squares (PLS) modelling with the objective of explaining and predicting changes in the BOD output of the reactor. Over two years of data with 87 process measurements were used to build the models. Variables were collected from the MBBR control scheme as well as upstream in the bleach plant and in digestion. To account for process dynamics, a variable lagging approach was used for variables with significant temporal correlations. It was found that wood type pulped at the mill was a significant variable governing reactor performance. Other important variables included flow parameters, faults in the temperature or pH control of the reactor, and some potential indirect indicators of biomass activity (residual nitrogen and pH out). The most predictive model was found to have an RMSEP value of 606 kgBOD/d, representing a 14.5% average error. This was a good fit, given the measurement error of the BOD test. Overall, the statistical approach was effective in describing and predicting MBBR treatment performance.
The responsibility of the pulp and paper sector with regard to sustainable development: how much is enough?
Authors: Kiperstok A. , Silva C.M.
Published: March 2007

Pulp and paper companies all over the world certify their environmental management systems assuming public commitments for the continuous improvement of their relationship with the environment. Once certified, they consider themselves having done their part. But is this enough? This work has been carried out with the clear intention of provoking the professionals who can give the much needed answers for the construction of environmental sustainability in the pulp and paper sector.
The impact of reduced phosphorus levels on microbial floc properties during biological treatment of pulp and paper wastewaters
Authors: Liu J.R. , Liss S.N.
Published: March 2007

The effect of limiting P in activated sludge was investigated in laboratory scale sequencing batch reactors (SBRs) fed effluent from a container board mill. Floc characterization included measurement of hydrophobicity, surface charge, and analysis of extracellular polymeric substances (EPS). Reactor performance was assessed by monitoring COD and inorganic P removal, MLSS, and sludge settleability (SVI and batch settling flux) over a period of eight months. Control reactors (BOD:N:P of 100:5:1) were compared to reactors run under P-limited conditions (100:5:0.3; 100:5:0.1). Reactor performance at lower temperatures (14 °C; control = 26 °C) was also studied to assess the impact of P-limitation. Changes in floc structure and the composition of EPS occurred within 1 to 3 days following a reduction in P levels. There was an insignificant increase in SVI; however, gravitational settling velocity and batch settling flux values for low P floc were consistently higher than for floc generated under control conditions. Lower temperatures (14 °C) resulted in a deterioration in floc settling properties at a BOD:N:P of 100:5:1. This impact on settling was significantly reduced at a BOD:P of 100:0.1. Reducing P concentrations in the wastewater treatment system has the potential to improve sludge settleability and reduce final P discharges.
The optimal size of dynamic phosphorus models for coastal areas
Authors: Malmaeus J.M. , Karlsson O.M. , Lindgren D. , Eklund J.
Published: March 2007

One method to assess environmental effects from industrial emissions to coastal and inland waters, e.g. from pulp and paper industries, is to quantify these emissions with mass balance models. In this study six different mass balance models for phosphorus with varying degrees of complexity have been tested in 11 Swedish coastal areas. The majority of these areas are recipients of pulp and paper industries. The accuracy of model predictions of phosphorus and chlorophyll is evaluated and compared between models. The results imply that for the included water bodies, models containing state variables for phosphorus in surface water and deep water are superior to models treating the water column as a completely mixed entity. The results do not justify the separation of phosphorus into dissolved and particulate fractions, but for chlorophyll predictions the results were significantly improved when phytoplankton was included as a state variable. Unless detailed descriptions or predictions of chlorophyll dynamics are required, modelling eutrophication in coastal areas may be considered as a matter of total phosphorus in two water compartments plus sediments.