bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between Unconstrained Arm Movements and Single-Neuron Firing in the Macaque Motor Cortex
Authors: Aflalo Tyson N. , Graziano Michael S. A.
Published: March 2007

The activity of single neurons in the monkey motor cortex was studied during semi-naturalistic, unstructured arm movements made spontaneously by the monkey and measured with a high resolution three-dimensional tracking system. We asked how much of the total neuronal variance could be explained by various models of neuronal tuning to movement. On average, tuning to the speed of the hand accounted for 1% of the total variance in neuronal activity, tuning to the direction of the hand in space accounted for 8%, a more complex model of direction tuning, in which the preferred direction of the neuron rotated with the starting position of the arm, accounted for 13%, tuning to the final position of the hand in Cartesian space accounted for 22%, and tuning to the final multijoint posture of the arm accounted for 36%. One interpretation is that motor cortex neurons are significantly tuned to many control parameters important in the animal's repertoire, but that different control parameters are represented in different proportion, perhaps reflecting their prominence in everyday action. The final posture of a movement is an especially prominent control parameter although not the only one. A common mode of action of the monkey arm is to maintain a relatively stable overall posture while making local adjustments in direction during performance of a task. One speculation is that neurons in motor cortex reflect this pattern in which direction tuning predominates in local regions of space and postural tuning predominates over the larger workspace.
Protein Phosphatase 2A Methyltransferase Links Homocysteine Metabolism with Tau and Amyloid Precursor Protein Regulation
Authors: Sontag Estelle , Nunbhakdi-Craig Viyada , Sontag Jean-Marie , Diaz-Arrastia Ramon , Ogris Egon , Dayal Sanjana , Lentz Steven R. , Arning Erland , Bottiglieri Teodoro
Published: March 2007

Alzheimer's disease (AD) neuropathology is characterized by the accumulation of phosphorylated tau and amyloid-β peptides derived from the amyloid precursor protein (APP). Elevated blood levels of homocysteine are a significant risk factor for many age-related diseases, including AD. Impaired homocysteine metabolism favors the formation ofS-adenosylhomocysteine, leading to inhibition of methyltransferase-dependent reactions. Here, we show that incubation of neuroblastoma cells withS-adenosylhomocysteine results in reduced methylation of protein phosphatase 2A (PP2A), a major brain Ser/Thr phosphatase, most likely by inhibiting PP2A methyltransferase (PPMT). PP2A methylation levels are also decreased after ectopic expression of PP2A methylesterase in Neuro-2a (N2a) cells. Reduced PP2A methylation promotes the downregulation of Bα-containing holoenzymes, thereby affecting PP2A substrate specificity. It is associated with the accumulation of both phosphorylated tau and APP isoforms and increased secretion of β-secretase-cleaved APP fragments and amyloid-β peptides. Conversely, incubation of N2a cells withS-adenosylmethionine and expression of PPMT enhance PP2A methylation. This leads to the accumulation of dephosphorylated tau and APP species and increased secretion of neuroprotective α-secretase-cleaved APP fragments. Remarkably, hyperhomocysteinemia induced in wild-type and cystathionine-β-synthase +/− mice by feeding a high-methionine, low-folate diet is associated with increased brainS-adenosylhomocysteine levels, PPMT downregulation, reduced PP2A methylation levels, and tau and APP phosphorylation. We reported previously that downregulation of neuronal PPMT and PP2A methylation occur in affected brain regions from AD patients. The link between homocysteine, PPMT, PP2A methylation, and key CNS proteins involved in AD pathogenesis provides new mechanistic insights into this disorder.
Reelin Depletion in the Entorhinal Cortex of Human Amyloid Precursor Protein Transgenic Mice and Humans with Alzheimer's Disease
Authors: Chin Jeannie , Massaro Catherine M. , Palop Jorge J. , Thwin Myo T. , Yu Gui-Qiu , Bien-Ly Nga , Bender Aaron , Mucke Lennart
Published: March 2007

Reelin regulates nervous system development and modulates synaptic plasticity in the adult brain. Several findings suggest that alterations in Reelin signaling may contribute to neuronal dysfunction associated with Alzheimer's disease (AD). Cell surface receptors for Reelin, including integrins and very-low-density lipoprotein receptor/apolipoprotein E2 receptor, may be targets of amyloid-β (Aβ) peptides presumed to play key roles in the pathogenesis of AD. Reelin also regulates the extent of tau phosphorylation. Finally, increased amounts of Reelin fragments have been found in CSF from AD patients, suggesting altered processing of Reelin. We therefore hypothesized that Reelin levels might be altered in the brains of human amyloid precursor protein (hAPP) transgenic mice, particularly in brain regions vulnerable to AD such as hippocampus and entorhinal cortex. Compared with nontransgenic controls, hAPP mice had significantly fewer Reelin-expressing pyramidal cells in the entorhinal cortex, the major population of glutamatergic neurons expressing Reelin in the brain. Western blot analysis of the hippocampus, which receives projections from the entorhinal cortex, revealed significant reductions in Reelin levels. In contrast, the number of Reelin-expressing GABAergic interneurons was not altered in either the entorhinal cortex or the hippocampus. Thus, neuronal expression of hAPP/Aβ is sufficient to reduce Reelin expression in a specific population of entorhinal cortical pyramidal neuronsin vivo. Underscoring the relevance of these findings, we found qualitatively similar reductions of Reelin-expressing pyramidal neurons in the entorhinal cortex of AD brains. We conclude that alterations in Reelin processing or signaling may be involved in AD-related neuronal dysfunction.
Brain-Derived Neurotrophic Factor Promotes Long-Term Potentiation-Related Cytoskeletal Changes in Adult Hippocampus
Authors: Rex Christopher S. , Lin Ching-Yi , Kramár Eniko A. , Chen Lulu Y. , Gall Christine M. , Lynch Gary
Published: March 2007

Brain-derived neurotrophic factor (BDNF) is an extremely potent, positive modulator of theta burst induced long-term potentiation (LTP) in the adult hippocampus. The present studies tested whether the neurotrophin exerts its effects by facilitating cytoskeletal changes in dendritic spines. BDNF caused no changes in phalloidin labeling of filamentous actin (F-actin) when applied alone to rat hippocampal slices but markedly enhanced the number of densely labeled spines produced by a threshold level of theta burst stimulation. Conversely, the BDNF scavenger TrkB–Fc completely blocked increases in spine F-actin produced by suprathreshold levels of theta stimulation. TrkB–Fc also blocked LTP consolidation when applied 1–2 min, but not 10 min, after theta trains. Additional experiments confirmed that p21 activated kinase and cofilin, two actin-regulatory proteins implicated in spine morphogenesis, are concentrated in spines in mature hippocampus and further showed that both undergo rapid, dose-dependent phosphorylation after infusion of BDNF. These results demonstrate that the influence of BDNF on the actin cytoskeleton is retained into adulthood in which it serves to positively modulate the time-dependent LTP consolidation process.
Activity of Inferior Temporal Cortical Neurons Predicts Recognition Choice Behavior and Recognition Time during Visual Search
Authors: Mruczek Ryan E. B. , Sheinberg David L.
Published: March 2007

Although the selectivity for complex stimuli exhibited by neurons in inferior temporal cortex is often taken as evidence of their role in visual perception, few studies have directly tested this hypothesis. Here, we sought to create a relatively natural task with few behavioral constraints to test whether activity in inferior temporal cortex neurons predicts whether or not a monkey will recognize and respond to a complex visual object. Monkeys were trained to freely view an array of images and report the presence of one of many possible target images previously associated with a hand response. On certain trials, the identity of the target was swapped during the monkeys' targeting saccade. Furthermore, the response association of the preswap target and the postswap target differed (e.g., right-to-left target swap). Neural activity in cells selective for the preswap target was significantly higher when the monkeys' response matched the hand association of the preswap target. Furthermore, the monkeys' response time was predicted by the magnitude of the presaccadic firing rate on nonswap trials. Our results provide additional support for the role of inferior temporal cortex in object recognition during natural behavior.
The Prefrontal Cortex as a Key Target of the Maladaptive Response to Stress
Authors: Cerqueira João J. , Mailliet François , Almeida Osborne F. X. , Jay Thérèse M. , Sousa Nuno
Published: March 2007

Research on the detrimental effects of stress in the brain has mainly focused on the hippocampus. Because prefrontal cortex (PFC) dysfunction characterizes many stress-related disorders, we here analyzed the impact of chronic stress in rats on the integrity of the hippocampal–PFC pathway, monitored by behavioral and electrophysiological function and morphological assessment. We show that chronic stress impairs synaptic plasticity by reducing LTP induction in the hippocampal–PFC connection; in addition, it induces selective atrophy within the PFC and severely disrupts working memory and behavioral flexibility, two functions that depend on PFC integrity. We also demonstrate that short periods of stress exposure induce spatial reference memory deficits before affecting PFC-dependent tasks, thus suggesting that the impairment of synaptic plasticity within the hippocampus-to-PFC connection is of relevance to the stress-induced PFC dysfunction. These findings evidence a fundamental role of the PFC in maladaptive responses to stress and identify this area as a target for intervention in stress-related disorders.
HCN Pacemaker Channel Activation Is Controlled by Acidic Lipids Downstream of Diacylglycerol Kinase and Phospholipase A2
Authors: Fogle Keri J. , Lyashchenko Alex K. , Turbendian Harma K. , Tibbs Gareth R.
Published: March 2007

Hyperpolarization-activated pacemaker currents (IH) contribute to the subthreshold properties of excitable cells and thereby influence behaviors such as synaptic integration and the appearance and frequency of intrinsic rhythmic activity. Accordingly, modulation ofIHcontributes to cellular plasticity. AlthoughIHactivation is regulated by a plethora of neurotransmitters, including some that act via phospholipase C (PLC), the only second messengers known to alterIHvoltage dependence are cAMP, internal protons (H+Is), and phosphatidylinositol-4,5-phosphate. Here, we show that 4β-phorbol-12-myristate-13-acetate (4βPMA), a stereoselective C-1 diacylglycerol-binding site agonist, enhances voltage-dependent opening of wild-type and cAMP/H+I-uncoupled hyperpolarization-activated, cyclic nucleotide-regulated (HCN) channels, but does not alter gating of the plant hyperpolarization-activated channel, KAT1. Pharmacological analysis indicates that 4βPMA exerts its effects on HCN gating via sequential activation of PKC and diacylglycerol kinase (DGK) coupled with upregulation of MAPK (mitogen-activated protein kinase) and phospholipase A2 (PLA2), but its action is independent of phosphoinositide kinase 3 (PI3K) and PI4K. Demonstration that both phosphatidic acid and arachidonic acid (AA) directly facilitate HCN gating suggests that these metabolites may serve as the messengers downstream of DGK and PLA2, respectively. 4βPMA-mediated suppression of the maximal HCN current likely arises from channel interaction with AA coupled with an enhanced membrane retrieval triggered by the same pathways that modulate channel gating. These results indicate that regulation of excitable cell behavior by neurotransmitter-mediated modulation ofIHmay be exerted via changes in three signaling lipids in addition to the allosteric actions of cAMP and H+Is.
Missorting of Tau in Neurons Causes Degeneration of Synapses That Can Be Rescued by the Kinase MARK2/Par-1
Authors: Thies Edda , Mandelkow Eva-Maria
Published: March 2007

Early hallmarks of Alzheimer's disease include the loss of synapses, which precedes the loss of neurons and the pathological phosphorylation and aggregation of tau protein. Mitochondrial dysfunction has been suggested as a reason, but evidence on the role of tau was lacking. Here, we show that transfection of tau in mature hippocampal neurons leads to an improper distribution of tau into the somatodendritic compartment with concomitant degeneration of synapses, as seen by the disappearance of spines and of presynaptic and postsynaptic markers. This is accompanied by transport inhibition of vesicles and organelles, concomitant with an increase and bundling of microtubules. Mitochondria degenerate, thus causing ATP levels to decrease. The tau-induced synaptic decay can be relieved by the activation of the kinase MARK2 (microtubule-associated protein/microtubule affinity regulating kinase 2)/Par-1 (protease-activated receptor 1), which can remove tau from the microtubule tracks and reverses the transport block. This leads to the rescue of dendritic spines, synapses, mitochondrial transport and ATP levels.
The Glutamate and Chloride Permeation Pathways Are Colocalized in Individual Neuronal Glutamate Transporter Subunits
Authors: Leary Gregory P. , Stone Emily F. , Holley David C. , Kavanaugh Michael P.
Published: March 2007

Glutamate transporters have a homotrimeric subunit structure with a large central water-filled cavity that extends partially into the plane of the lipid bilayer (Yernool et al., 2004). In addition to uptake of glutamate, the transporters also mediate a chloride conductance that is increased in the presence of substrate. Whether the chloride channel is located in the central pore of the trimer or within the individual subunits has been controversial. We find that coexpression of wild-type neuronal glutamate transporter EAAT3 subunits with subunits mutated at R447, a residue governing substrate selectivity (Bendahan et al., 2000), results in transport activity consistent with two distinct noninteracting populations of transporters, in agreement with previous work suggesting that each subunit operates independently to transport substrate (Awes et al., 2004; Grewer et al., 2005; Koch and Larsson, 2005). In wild-type homotrimeric transporters, the glutamate concentration dependence of the anion conductance and the kinetics of glutamate flux were isolated and measured, and the anion channel activation was fitted to analytical expressions corresponding to (1) a central pore gated by binding to one or more subunits and (2) a channel pore in each subunit. The data indicate that glutamate-binding sites, transport pathways, and chloride channels reside in individual subunits in a trimer and function independently.
Status Epilepticus-Induced Somatostatinergic Hilar Interneuron Degeneration Is Regulated by Striatal Enriched Protein Tyrosine Phosphatase
Authors: Choi Yun-Sik , Lin Stanley L. , Lee Boyoung , Kurup Pradeep , Cho Hee-Yeon , Naegele Janice R. , Lombroso Paul J. , Obrietan Karl
Published: March 2007

Excitotoxic cell death is one of the precipitating events in the development of temporal lobe epilepsy. Of particular prominence is the loss of GABAergic hilar neurons. Although the molecular mechanisms responsible for the selective vulnerability of these cells are not well understood, activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway has been implicated in neuroprotective responses to excitotoxicity in other neuronal populations. Here, we report that high levels of the striatal-enriched protein tyrosine phosphatase (STEP), a key regulator of ERK/MAPK signaling, are found in vulnerable somatostatin-immunoreactive hilar interneurons. Under both control conditions and after pilocarpine-induced status epilepticus (SE), ERK/MAPK activation was repressed in STEP-immunoreactive hilar neurons. This contrasts with robust SE-induced ERK/MAPK activation in the granule cell layer of the dentate gyrus, a cell region that does not express STEP. During pilocarpine-induced SE,in vivodisruption of STEP activity allowed activation of the MAPK pathway, leading to immediate-early gene expression and significant rescue from cell death. Thus, STEP increases the sensitivity of neurons to SE-induced excitotoxicity by specifically blocking a latent neuroprotective response initiated by the MAPK pathway. These findings identify a key set of signaling events that render somatostatinergic hilar interneurons vulnerable to SE-induced cell death.
Natural Oligomers of the Alzheimer Amyloid-β Protein Induce Reversible Synapse Loss by Modulating an NMDA-Type Glutamate Receptor-Dependent Signaling Pathway
Authors: Shankar Ganesh M. , Bloodgood Brenda L. , Townsend Matthew , Walsh Dominic M. , Selkoe Dennis J. , Sabatini Bernardo L.
Published: March 2007

Alzheimer's disease (AD) is characterized by decreased synapse density in hippocampus and neocortex, and synapse loss is the strongest anatomical correlate of the degree of clinical impairment. Although considerable evidence supports a causal role for the amyloid-β protein (Aβ) in AD, a direct link between a specific form of Aβ and synapse loss has not been established. We demonstrate that physiological concentrations of naturally secreted Aβ dimers and trimers, but not monomers, induce progressive loss of hippocampal synapses. Pyramidal neurons in rat organotypic slices had markedly decreased density of dendritic spines and numbers of electrophysiologically active synapses after exposure to picomolar levels of soluble oligomers. Spine loss was reversible and was prevented by Aβ-specific antibodies or a small-molecule modulator of Aβ aggregation. Mechanistically, Aβ-mediated spine loss required activity of NMDA-type glutamate receptors (NMDARs) and occurred through a pathway involving cofilin and calcineurin. Furthermore, NMDAR-mediated calcium influx into active spines was reduced by Aβ oligomers. Partial blockade of NMDARs by pharmacological antagonists was sufficient to trigger spine loss. We conclude that soluble, low-noligomers of human Aβ trigger synapse loss that can be reversed by therapeutic agents. Our approach provides a quantitative cellular model for elucidating the molecular basis of Aβ-induced neuronal dysfunction.
Neural Changes in Control Implementation of a Continuous Task
Authors: Lungu Ovidiu V. , Binenstock Meagan M. , Pline Megan A. , Yeaton Jennifer R. , Carey James R.
Published: March 2007

It is commonly agreed that control implementation, being a resource-consuming endeavor, is not exerted continuously or in simple tasks. However, most research in the field was done using tasks that varied the need for control on a trial-by-trial basis (e.g., Stroop, flanker) in a discrete manner. In this case, the anterior cingulate cortex (ACC) was found to monitor the need for control, whereas regions in the prefrontal cortex (PFC) were found to be involved in control implementation. Whether or not the same control mechanism would be used in continuous tasks was an open question. In our study, we found that in a continuous task, the same neural substrate subserves control monitoring (ACC) but that the neural substrate of control implementation changes over time. Early in the task, regions in the PFC were involved in control implementation, whereas later the control was taken over by subcortical structures, specifically the caudate. Our results suggest that humans possess a flexible control mechanism, with a specific structure dedicated to monitoring the need for control and with multiple structures involved in control implementation.
Verbesserung von Lidarsensoren für Komfort- und Sicherheitssysteme durch angewandte Signalverarbeitung (Improving Lidar Sensor Performance for Comfort and Safety Applications by Applied Signal Processing)
Authors: Lichte Bernd , Waßmuth Joachim
Published: March 2007

Im Beitrag wird ein Multi-Beam-Lidarsensor vorgestellt, der speziell für den Einsatz in Fahrerassistenzsystemen wie Adaptive Cruise Control (ACC) entwickelt wurde. Da so genannte 76–77 GHz Long-Range-Radarsensoren derzeit die größte Verbreitung im Markt besitzen, werden beide Sensorsysteme bezüglich Umfelderfassung und Robustheit verglichen. Während Lidarsensoren den Abstand vergleichbar, die laterale Position und die Breite von Objekten sogar wesentlich besser erfassen, messen Long-Range-Radarsensoren die Relativgeschwindigkeit von Objekten über den Doppler-Effekt direkt. Es wird beschrieben, wie dieser Nachteil durch Methoden der digitalen Signalverarbeitung auch unter Berücksichtigung einer Festkomma-Arithmetik nahezu kompensiert werden konnte. Zudem werden die Entwicklungsumgebung und die Methodik vorgestellt und die Ergebnisse anhand von im Testfahrzeug aufgezeichneter Messdaten veranschaulicht.
The design and construction of Itford Farm Bridleway Bridge
Authors: Oliver A.
Published: March 2007

Until recently, users of the South Downs Way National Trail had been finding it increasingly difficult and dangerous to cross the busy A26 trunk road and the provision of a segregated crossing had become increasingly necessary. On behalf of the Highways Agency, InterRoute embarked on the design and construction of a suitable crossing. A structural timber beam or truss bridge was initially investigated but this was later rejected in favour of a structural steel solution with timber cladding. A steel truss superstructure was used for ease, speed and convenience of construction, and timber was used for its aesthetic qualities on most of the visible parts of the bridge. Effort was made, within the constraints of the budget, to design a bridge in harmony with its rural setting, a designated Area of Outstanding Natural Beauty. The chosen configuration, a three-span arrangement with curves in both vertical and horizontal axes, was selected to harmonise with the rolling hills of the Sussex Downland.
Precast deck systems for steel-concrete composite bridges
Authors: Gordon S. R. , May I. M.
Published: March 2007

This paper reviews the recent application of precast deck systems for all forms of bridge but with particular emphasis on steel-concrete composite bridges. The many forms of precast elements are discussed including full-depth and partial-depth units (which require an in situ concrete topping) and the use of permanent formwork systems. Examples of the use of precast decks in Europe, in particular in Scandinavia, the Far East and the USA are highlighted. The development of ‘steel-free’ decks in Canada is also discussed.
Fluorescent In Situ Hybridization and Micro‐autoradiography Applied to Ecophysiology in Soil
Authors: Rogers Shane W. , Moorman Thomas B. , Ong Say Kee
Published: March 2007

Soil microbial communities perform many important processes, including nutrient cycling, plant–microorganism interactions, and degradation of xenobiotics. The study of microbial communities, however, has been limited by cultural methods, which may greatly underestimate diversity. The advent of nucleic acids technologies allows microbial communities to be quantified and classified without the limitations of cultivation. Fluorescent in situ hybridization (FISH) and other tools of molecular ecology are now being used to investigate community structure and diversity of soils, aquifers, and other natural habitats. Based on these studies, soil microbial communities are diverse and appear to respond to anthropogenic inputs, such as fertilizer, manure, and pollutants, as well as the more well‐known constraints imposed by temperature and moisture. Yet most nucleic‐acids‐based technologies are unable to directly link phylogeny with processes in a manner similar to cultivation‐based approaches, restricting the conclusions that can be drawn from the large data sets they generate. Recently, the combination of FISH with microautoradiography (FISH‐MAR) allows cells active in processes to be quantified and simultaneously classified phylogenetically. In this review, we discuss how FISH‐MAR can be used to quantify the specific microbial phylotype(s) responsible for a microbially catalyzed process. Examples of the use of FISH and FISH‐MAR in soils and sediments are described. The capabilities and limitations of these techniques for linking microbial community structure and function are discussed.
DNA Sequencing: Strategies for Soil Microbiology
Authors: Zwolinski Michele D.
Published: March 2007

Sequencing of DNA is a powerful tool for gathering information about organisms and their environments. The 16S rRNA gene has been the preferred gene target for describing soil microbial diversity and for establishing phylogenetic relationships between unknown and uncultivated microorganisms. As sequencing technologies improve and computing power increases, however, longer and more accurate sequence data is becoming available. It is now possible to generate complete genome sequences for individual organisms and even to collect whole‐environment genome, or metagenomic, sequence information. The genomes of isolated soil microorganisms have been used to describe the physiology, ecology, and evolution and have lead to important discoveries in medicine and industry. Soil metagenomic libraries contain too much information to sequence completely at this time, but can be mined for novel, and potentially useful, microbial processes and can be used to compare genetic diversity between habitats.
Soil Factors Influencing Suspended Sediment Flocculation by Polyacrylamide
Authors: McLaughlin Richard A. , Bartholomew Nathanael
Published: March 2007

Turbidity in stormwater runoff may be treated with polyacrylamide (PAM) to flocculate suspended sediment, but the relationships between PAM properties and those of the suspended sediment have not been widely studied. Our objective was to determine how soil physical and chemical properties affected flocculation by PAMs with a variety of characteristics. Subsoil materials were collected from 13 active construction sites around North Carolina. These were tested for flocculation using PAMs with charge densities of 0 to 50% and molecular weights of 14 to 28 Mg mol−1, at concentrations of 0.025 to 10 mg L−1 Soil was added to solutions of single and mixed PAMs with various molecular weights and charge densities and the turbidity was measured 30 s after mixing. Five kaolinitic subsoils had linear responses to PAM regardless of molecular weight or charge density, with an optimal dose of 1 to 2 mg L−1 to obtain >96% reduction in turbidity. Increased turbidity, indicating stabilization, occurred for two additional soils with anionic PAM concentrations >0.5 mg L−1, but a neutral or a mixed anionic PAM product reduced turbidity at those concentrations. The remaining six suboils had widely differing patterns of response, including little or no turbidity reduction with any single anionic PAM. Increasing smectite and vermiculite content (>20%) in suboils from the Coastal Plain reduced the effectiveness of single, anionic PAMs for flocculation. The mixed anionic PAM, however, reduced turbidity in most subsoils and did not have a stabilization reaction at higher concentrations (1–5 mg L−1). Texture, mineralogy, and extractable Fe were highly correlated with reductions in turbidity with PAM, but most of the differences in flocculation occurred in subsoils with 20% or more smectite or vermiculite.
THE EFFECT OF AGE AND CULTURE ON THE CAUSES OF LONELINESS
Authors: Rokach Ami
Published: March 2007

This study examined the influence of age and cultural background on the causes of loneliness. A total of 194 Canadians and 209 participants from the Czech Republic formed the participant pool. Rather than comparing the two populations and disregarding within and between the age differences the cultural groups were divided into age subgroups. These were young adults (18–30 years old), adults (31–59), and seniors (60–89). Participants answered a 29-item yes/no questionnaire composed of 5 subscales, namely: Personal Inadequacies, Developmental Deficits, Unfulfilling Intimate Relationships, Relocation/Significant Separations, and Social Marginality. The age groups within and between cultures also differed significantly.
FACTORS OF THE THINKING DISPOSITION OF JAPANESE HIGH SCHOOL STUDENTS
Authors: Kawashima Noriaki , Shiomi Kunio
Published: March 2007

This study measured high school students' thought disposition through a questionnaire on critical thinking. Factor analysis of the questionnaire revealed 4 factors that showed the aspects of thought disposition. Each factor score was examined to determine differences relating to
gender and student grade level. The results showed that no significant differences were identified except in one factor. The thought disposition of high school teachers was also measured. The results of a comparative examination between students and teachers revealed significant differences.
A COMPARATIVE STUDY OF THE EFFECTS OF TAIWAN-UNITED STATES EMPLOYEE CATEGORIZATION ON SUPERVISOR TRUST
Authors: Hu Hsiu-Hua
Published: March 2007

This study used a 2×2×2 within-subjects of scenario experiment design to examine the effects of 3 key employee categorization criteria – relationship (guanxi), loyalty and competence – on the trust attitudes of 217 Taiwan and 132 United States corporate managers. The results revealed that U.S. supervisors display cognition-based trust (reliability and competence) toward their subordinates, which is primarily based on each subordinate's level of competence, whereas Taiwan supervisors display affect-based trust (affectionate attachment) based on the closeness of their relationship with the subordinate. Limitations of the study and suggestions for further research are discussed.
A CROSS-CULTURAL VALIDATION OF ADOLESCENT SELF-CONCEPT IN TWO CULTURES: JAPAN AND SWEDEN
Authors: Nishikawa Saori , Norlander Torsten , Fransson Per , Sundbom Elisabet
Published: March 2007

The psychometric properties of the SDQII (Self-Description Questionnaire II; Marsh, 1992) were examined, and the extent to which Japanese and Swedish adolescents differ in their self-concepts and actual-ideal discrepancies was investigated. Further gender differences were explored.
The SDQII and Actual-Ideal Questionnaires (designed for this study) were administered to 144 Japanese and 96 Swedish adolescents (range = 14 to 15 years). The main results show that the psychometric properties of the SDQII were satisfactory in both cultures, making these instruments useful
in further investigations. Japanese adolescents generally reported a lower self-concept (with the exception of physical and math self-concepts) and higher self-discrepancies than did the Swedish adolescents. In addition, the gender differences were smaller compared to the influence of the
cultural effect.
The CFTR-derived peptides as a model of sequence-specific protein aggregation
Authors: Bąk Daniel , Cutting Garry , Milewski Michał
Published: March 2007

Protein aggregation is a hallmark of a growing group of pathologies known as conformational diseases. Although many native or mutated proteins are able to form aggregates, the exact amino acid sequences involved in the process of aggregation are known only in a few cases. Hence, there is a need for different model systems to expand our knowledge in this area. The so-called ag region was previously found to cause the aggregation of the C-terminal fragment of the cystic fibrosis transmembrane conductance regulator (CFTR). To investigate whether this specific amino acid sequence is able to induce protein aggregation irrespective of the amino acid context, we altered its position within the CFTR-derived C-terminal peptide and analyzed the localization of such modified peptides in transfected mammalian cells. Insertion of the ag region into a different amino acid background affected not only the overall level of intracellular protein aggregation, but also the morphology and subcellular localization of aggregates, suggesting that sequences other than the ag region can substantially influence the peptide’s behavior. Also, the introduction of a short dipeptide (His-Arg) motif, a crucial component of the ag region, into different locations within the C-terminus of CFTR lead to changes in the aggregation pattern that were less striking, although still statistically significant. Thus, our results indicate that even subtle alterations within the aggregating peptide can affect many different aspects of the aggregation process.
Second Generation Nanostructured Metal Oxide Matrices to Increase the Thermal Stability of CO and NO2 Sensing Layers Based on Iron(II) Phthalocyanine
Authors: Fernández‐Sánchez J. F. , Fernández I. , Steiger R. , Beer R. , Cannas R. , Spichiger‐Keller U. E.
Published: March 2007

An iron(II) phthalocyanine (FePc) complex solubilized by decylamine (DA) and benzylamine (BA) is incorporated into a nanoparticulate metal oxide matrix to develop optical sensor films sensitive to NO2 and CO. Eleven amine solvents have been tested as N‐donor ligands that permit ligand exchange with the gas molecules. We have systematically investigated the suitability of different N‐donor ligands, studied the thermal stability of the NO2‐ and CO‐sensing films at 4, 25, 60, and 80 °C by photometry, and corroborated our findings by using NMR experiments. A satisfactory thermal stability of the films has not been obtained for chemically unmodified nanoparticulate metal oxide matrices. We have therefore developed a second generation of nanostructured metal oxide supports that show increased thermal stability and adequate sensitivity to NO2 and CO. These novel nanostructured matrices have been chemically modified using amines, alumina oligomers, and/or anti‐gas‐fading agents. These components have been integrated into the metal oxide matrices to avoid degradation of the optical films and to preserve their sensitivity.
3D π‐Conjugated Oligothiophenes Based on Sterically Twisted Bithiophene Nodes
Authors: Karpe S. , Cravino A. , Frère P. , Allain M. , Mabon G. , Roncali J.
Published: March 2007

3D conjugated architectures consisting of short oligothiophene chains attached to a connecting node formed by a sterically twisted bithiophenic system have been synthesized by various combinations of bromination and organometallic couplings. The analysis of the electronic properties of these systems by UV‐vis absorption spectroscopy and cyclic voltammetry shows that the effective conjugation length depends on the twist angle in the central bithiophene node and on the number, length, and composition of the conjugated branches. A first evaluation of the potential of this new class of compounds for the realization of organic solar cells has been carried out. To this end two prototype bulk heterojunctions based on two representative compounds as donors and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) as acceptor have been realized. A short‐circuit current density of 1.33 mA cm–2 and a power conversion efficiency of 0.20 % have been measured under AM 1.5 (air‐mass 1.5) simulated solar irradiation.
Effects of Annealing on the Nanomorphology and Performance of Poly(alkylthiophene):Fullerene Bulk‐Heterojunction Solar Cells
Authors: Nguyen L. H. , Hoppe H. , Erb T. , Günes S. , Gobsch G. , Sariciftci N. S.
Published: March 2007

The evolution of nanomorphology within thin solid‐state films of poly(3‐alkylthiophene):[6,6]‐phenyl‐C61 butyric acid methyl ester (P3AT:PCBM) blends during the film formation and subsequent thermal annealing is reported. In detail, the influence of the P3AT's alkyl side chain length on the polymer/fullerene phase separation is discussed. Butyl, hexyl, octyl, decyl, and dodecyl side groups are investigated. All of the P3ATs used were regioregular. To elucidate the nanomorphology, atomic force microscopy (AFM), X‐ray diffraction, and optical spectroscopy are applied. Furthermore, photovoltaic devices of each of the different P3ATs have been constructed, characterized, and correlated with the nanostructure of the blends. It is proposed that the thermal‐annealing step, commonly applied to these P3AT:PCBM blend films, controls two main issues at the same time: a) the crystallization of P3AT and b) the phase separation and diffusion of PCBM. The results show that PCBM diffusion is the main limiting process for reaching high device performances.
Glucocorticoid levels in free ranging resident mantled howlers: a study of coping strategies
Authors: Cristóbal‐azkarate Jurgi , Chavira Roberto , Boeck Lourdes , Rodríguez‐luna Ernesto , VEÀ Joaquím J.
Published: March 2007

A growing amount of data shows that
a preference for passive‐nonaggressive over
active‐aggressive problem solving is associated
with higher levels of glucocorticoids (GC). For
mantled howlers, the arrival of an adult male in a new
group is a potential source of psychological stress for
both resident males and females. Resident mantled howler
males take an active stand and aggressively repel the
entrance of solitary males, while females take a
passive‐nonaggressive stand. In order to study
whether the relationship between coping strategies and the
activation of the
hypothalamic‐pituitary‐adrenal
(HPA) axis observed in other species applies to
the response of resident mantled howlers to the presence
of solitary males, we examine the relationship between
different group and subpopulation variables and the GC
levels measured in feces collected from 10 groups living
in six forest fragments, in Los Tuxtlas, Mexico. The
results of our study suggest that the resident mantled
howler females' passive response to the presence of
solitary males is accompanied by the activation of the HPA
axis, whereas resident males' aggressive response is
not accompanied by any changes in the HPA axis. In
contrast, a previous study suggests that resident male
howlers respond by increasing their testosterone levels to
the presence of solitary males
(Cristobal‐Azkarate et al., Hormones and
Behavior 2006;49 261–267).These different
behavioral and hormonal responses coincide with the active
and passive coping styles described for other species. The
conditions in which howlers live in our study area may be
favoring the interaction between solitary and resident
howlers, and inducing chronically high GC levels, which in
turn could negatively affect the fitness of these
subpopulations. Am. J. Primatol. 69:866–876, 2007.
© 2007 Wiley‐Liss, Inc.
The function of teeth chattering in male Barbary macaques (Macaca sylvanus)
Authors: Wiper Susan M. , Semple Stuart
Published: March 2007

Teeth chattering is seen in many primate species and has been proposed to have a range of social functions. This observational study tested specific hypotheses relating to the function of teeth chattering in a semi‐free‐ranging group of Barbary macaques, Macaca sylvanus. During focal watches of males, the outcome of male–male dyadic social interactions in which teeth chattering was present or absent was compared. Using these data, we tested the predictions of four hypotheses: teeth chattering functions as a signal of submission, appeasement, affiliation or reassurance. Support was found for all four hypotheses. In addition, in some contexts, an exchange of teeth chattering appeared to have a greater impact on the outcome of interactions than one male alone giving this signal. These findings suggest that teeth chattering serves an important role in coordinating the social interactions of male Barbary macaques. Am. J. Primatol. 69:1179–1188, 2007. © 2007 Wiley‐Liss, Inc.
Sympathetic neural activity, sex dimorphism, and postural tachycardia syndrome
Authors: Bonyhay Istvan , Freeman Roy
Published: March 2007

Objective

To elucidate the mechanisms whereby postural tachycardia syndrome (POTS) patients maintain orthostatic blood pressure and explain the greater prevalence of female cases in POTS cohorts.

Methods

We investigated muscle sympathetic nerve (MSN) discharge characteristics in 12 female POTS patients and in 9 male and 12 female control subjects using the burst amplitude distribution and the relative contribution of burst frequency and burst amplitude.

Results

At rest, burst distribution was shifted toward larger amplitudes in POTS patients (p < 0.005), consistent with increased sympathetic activity. During hypotension, the distribution shifted toward larger amplitude bursts in control subjects (p < 0.001), whereas it did not change in POTS patients. Total MSN activity increase to hypotension did not differ between subject groups, but the relative contribution of burst frequency change to the total activity increase was greater in POTS patients than in female (p < 0.05) and male (p < 0.001) control subjects. In contrast, the relative contribution of burst amplitude change to total MSN activity increase was greater in male compared with female control subjects (p < 0.05) and POTS patients (p < 0.001).

Interpretation

At rest, the burst amplitude distribution was consistent with increased sympathetic activity in POTS and did not change in response to hypotension. In response to hypotension, burst frequency makes a proportionally greater contribution to the increase in total MSN activity in POTS patients compared with female control subjects, and female compared with male control subjects. These physiological differences in MSN discharge characteristics, in the setting of sympathetic fiber loss associated with POTS, may contribute to the predisposition to and greater prevalence of POTS in female individuals. Ann Neurol 2007
Synthesis of 4′‐Hydroxy‐3′‐piperidinomethylchalcone Derivatives and Their Cytotoxicity Against PC‐3 Cell Lines
Authors: Gul Halise I. , Yerdelen Kadir O. , Gul Mustafa , Das Umashankar , Pandit Bulbul , Li Pui‐Kai , Secen Hasan , Sahin Fikrettin
Published: March 2007

A new series of mono Mannich bases of 4′‐hydroxychalcones 2a–e carrying a variety of aryl groups was synthesized and the in vitro cytotoxic activities of the new compounds were screened against PC‐3 cell lines. Bioactivities of 2a–e, which are reported for the first time in this study, were compared against their precursor 4′‐hydroxychalcones 1a–e. Compound 2b was found to be the most potent (IC50 = 3.7 μM) among the compounds synthesized. In addition, the compounds 1a–c and 2d showed moderate cytotoxicity. Incorporation of the 3′‐piperidinomethyl group in 1b and 1d raised the potency by 1.68 and 2.19 times respectively and, therefore, seemed to be a noteworthy molecular modification. Correlations were noted between cytotoxicity and one or more physiochemical constants of the aryl ring as well as log P values for the compounds 2a–e. The significant improvement of cytotoxicity of 2b, 2d, and 2e against PC‐3 cell lines compared with their chalcone precursors suggests that the incorporation of a piperidinomethyl group is a useful molecular modification and further development of these compounds as candidate cytotoxic agents may be warranted.
Synthesis of Some Novel Substituted Purine Derivatives As Potential Anticancer, Anti‐HIV‐1 and Antimicrobial Agents
Authors: Rida Samia M. , Ashour Fawzia A. , El‐Hawash Soad A.M. , El‐Semary Mona M. , Badr Mona H.
Published: March 2007

In search of novel purine antimetabolites, a series of 8‐substituted methylxanthine derivatives was prepared in order to explore their in vitro anticancer, anti‐HIV‐1 and antimicrobial activities. The target compounds include: 8‐[(3‐substituted‐4‐oxo‐thiazolidin‐2‐ylidene)hydrazino]‐1,3‐dimethyl (or 1,3,7‐trimethyl)‐3,7‐dihydropurine‐2,6‐diones 5a–e, 8‐[(3,4‐disubstituted 2,3‐dihydrothiazol‐2‐ylidene)hydrazino]‐1,3,7‐trimethyl‐3,7‐dihydropurine‐2,6‐diones 6a–d and 8‐(5‐amino‐3‐arylpyrazol‐1‐yl)‐1,3‐dimethyl‐ (or 1,3,7‐trimethyl)‐3,7‐dihydropurine‐2,6‐diones 7a–g. The in vitro anticancer results revealed that compound 5d exhibited a super sensitivity profile towards leukemia K‐562 with a GI50 value of <0.01 μM. Compound 7c showed significant activity against colon cancer HCT‐15 and renal cancer CAKI‐1 (GI50 values of 0.47 and 0.78 μM, respectively). Compound 7a displayed high activity against colon cancer HCT‐15 (GI50 = 0.8 μM). The anti‐HIV‐1 results indicated that compound 6b displayed a good reduction of viral cytopathic effect (56.69%). The antimicrobial results showed that compound 5a was four times more active than ampicillin against P. aerugenosa (MIC = < 25 μg/mL), compound 5b had twice the activity of ampicillin, while compounds 5d, 7c and 7f were equipotent to ampicillin. On the other hand, compound 7a was equipotent to ampicillin against P. vulgaris (MIC = 50 μg/mL).
Introduction to Chemical Proteomics for Drug Discovery and Development
Authors: Han Sung‐Young , Hwan Kim Seong
Published: March 2007

A fundamental goal of chemical proteomics is to identify target proteins for bioactive small molecules and then apply them to drug discovery and development as valid and drugable targets. Here, we introduce integrated technologies for the rapid identification of target proteins, methodologies for validating them as drugable targets, and applications of chemical proteomics in drug discovery and development.
Novel Aldose Reductase Inhibitors Derived from 6‐[[(Diphenylmethylene)amino]oxy]hexanoic Acid
Authors: Rakowitz Dietmar , Piccolruaz Grete , Pirker Cornelia , Matuszczak Barbara
Published: March 2007

Starting from the recently identified aldose reductase inhibitor 6‐[[(diphenylmethylene)amino]oxy]hexanoic acid 1, the following systematic structural modifications were performed: (a) formal substitution of the phenyl rings, (b) isosteric replacement of the benzene core by the heteroarenes pyridine and thiophene, (c) formal reduction of the aromatic substructure and subsequent diminution of the cyclohexyl ring, (d) introduction of methylene spacer between C=N and the phenyl rings, and finally (e) formal ring closure in order to get derivatives of the tricycles fluorenone, xanthone, and thioxanthone, respectively. Out of these series, compounds 22–24 bearing disubstituted phenyl rings exhibit the highest inhibitory activity (IC50 value approx. 3 μM) which lie almost in the range of the reference sorbinil.
Steroid 9α‐Hydroxylation during Testosterone Degradation by Resting Rhodococcus equi Cells
Authors: Kim Yong‐ung , Han Jaehong , Lee Sang Sup , Shimizu Kuniyoshi , Tsutsumi Yuji , Kondo Ryuichiro
Published: March 2007

The conversion pathway of testosterone to androst‐4‐ene‐3,17‐dione and 9α‐hydroxy androstane metabolites, 9α‐hydroxyandrost‐4‐ene‐3,17‐dione and 9α,17β‐dihydroxyandrost‐4‐en‐3‐one was proposed for the ring degradation in steroids by a minimal liquid medium (NMMP)‐dispersed Rhodococcus equi ATCC 14887. The microorganism produced 9α‐hydroxy androstane metabolites from testosterone at high conversion ratio without the addition of ring degradation inhibitory agents. Several NMMP‐based media showed the similar effect on the microbial transformation, in which the respective molar yields of 9α‐hydroxyandrost‐4‐ene‐3,17‐dione and 9α,17β‐dihydroxyandrost‐4‐en‐3‐one were approx. 3 to 47% and approx. 3 to 11%, respectively, whereas nutrient broth, a rich medium, basically showed no accumulation. On the basis of this evidence, magnesium sulfate and casamino acids among the components of NMMP were found to compromise the determinant for the production of the 9α‐hydroxy androstane metabolites without appreciable decomposition of the steroid ring system.