bluuebunny/crossref_metadata_2025 huggingface dataset:
Pedagogical agents as learning companions: the impact of agent emotion and gender
Authors: Kim Y. , Baylor A.L. , Shen E.
Published: January 2007

Abstract The potential of emotional interaction between human and computer has recently interested researchers in human–computer interaction. The instructional impact of this interaction in learning environments has not been established, however. This study examined the impact of emotion and gender of a pedagogical agent as a learning companion (PAL) on social judgements, interest, self‐efficacy, and learning. Two experiments investigated separately the effects of a PAL's emotional expression and empathetic response. Experiment 1 focused on emotional expression (positive vs. negative vs. neutral) and gender (male vs. female) with a sample of 142 male and female college students in a computer literacy course. Experiment 2 investigated the impact of empathetic response (responsive vs. non‐responsive) and gender with 56 pre‐service teachers. Overall, the results yielded main and interaction effects of PAL emotion and gender on the dependent variables. In particular, the PAL's empathetic response had a positive impact on learner interest and self‐efficacy; PAL gender had a positive impact on recall. The findings imply that the emotion and the gender of the digital learning companion could be utilized to optimize college students' motivation and learning.
Modeling complex marine ecosystems: an investigation of two teaching approaches with fifth graders
Authors: Papaevripidou M. , Constantinou C.P. , Zacharia Z.C.
Published: January 2007

Abstract  This study investigated acquisition and transfer of the modeling ability of fifth graders in various domains. Teaching interventions concentrated on the topic of marine ecosystems either through a modeling‐based approach or a worksheet‐based approach. A quasi‐experimental (pre–post comparison study) design was used. The control group (n = 17) received a traditional worksheet‐based instruction about ecosystems, whereas the experimental group (n = 16) received an instruction which was based on Stagecast Creator, an object‐oriented programming tool, and a set of modeling‐based curriculum materials. Paper‐and‐pencil tests were used both before and after the study to evaluate students' development of specific modeling skills. The data analysis followed both qualitative and quantitative methods. The findings of the present study indicate that (i) the development of modeling ability was effectively enhanced through the modeling‐based approach, since, after instruction, students were able to transfer those aspects to unfamiliar contexts; in contrast, the more traditional worksheet‐based approach did not promote the development of the same aspects of the modeling skill; and (ii) Stagecast Creator enabled students to construct, test, revise and validate dynamic computer‐based models of a marine ecosystem through building, testing and debugging complex rules, routines and programs for simulating multiple behaviours and processes of marine species.
MLH1 germline epimutations in selected patients with early‐onset non‐polyposis colorectal cancer
Authors: Valle L , Carbonell P , Fernandez V , Dotor AM , Sanz M , Benitez J , Urioste M
Published: January 2007

Recently, the germline epigenetic inactivation of MLH1 has been reported in a number of patients with early‐onset colorectal cancer among other characteristics. The aim of the present study is to evaluate the presence of MLH1 germline epimutations in selected colorectal cancer patients suspected of hereditary non‐polyposis colorectal cancer (HNPCC) in order to determine in which patients the MLH1 epigenetic test should be performed. From a total of 109 microsatellite instability (MSI)‐positive HNPCC‐suspected patients, 11 showed a lack of MLH1 expression in tumor tissue and no germline mutations in the mismatch repair (MMR) genes. In nine of these cases and in three additional patients with multiple tumors, the study of the germline MLH1 promoter hypermethylation was performed by means of methylation‐specific PCR and combined bisulfite‐restriction analysis techniques. One of the selected patients resulted positive for the MLH1 epimutation, which was confirmed in the DNA extracted from buccal lavage. The patient with the epimutation had developed an epidermoid lip carcinoma and an early‐onset colorectal tumor with MSI, no MLH1 expression, and loss of heterozygosity of the gene. Parents and siblings did not carry the epigenetic alteration, suggesting a de novo mechanism. Although germline MLH1 epimutations seem to be mostly uncommon, when the cases are well selected, the probability of finding them increases. Thus, taking into account ours and previous reports, we propose that screening for MLH1 epimutations in blood DNA could be performed in early‐onset colorectal cancer patients with MSI, lack of MLH1 expression in the tumor, and no germline mutations in the MMR genes.
Sera from mice immunized with DNA encoding Porphyromonas gingivalis catalytic or adhesin part of HRgpA inhibit degradation of human fibronectin by HRgpA
Authors: Vågnes K. S. , Vågnes Ø. , Bakken V.
Published: January 2007

Gingipains are potent virulence factors of Porphyromonas gingivalis and are likely to be associated with the development of periodontitis. It is, therefore, suggested that gingipain inhibition by vaccination could be a useful therapy for adult periodontitis. This study investigated the ability of antibodies raised against the catalytic part and the adhesin/haemagglutinin part of HRgpA to prevent haemagglutination and fibronectin degradation caused by P. gingivalis. We constructed two DNA vaccines, one containing the adhesin part of HRgpA and one with the catalytic part of HRgpA. BALB/c mice were immunized intramuscularly with either catalytic‐part‐encoding plasmids, adhesin‐part‐encoding plasmids or empty control plasmids. Sera from mice immunized with the catalytic vaccine or the adhesin vaccine each showed inhibition of human fibronectin degradation. A DNA vaccine encoding the adhesin or catalytic part of HRgpA induces responses that inhibit the degradation of molecules important for the structure and function of gingival and bone tissues.
Autism in visually impaired individuals
Authors: MUKADDES NAHIT MOTAVALLI , KILINCASLAN AYSE , KUCUKYAZICI GOKCE , SEVKETOGLU TIMUR , TUNCER SAMURAY
Published: January 2007

Abstract The aim of the present study was to assess the prevalence and associated risk factors of autism in a sample of visually impaired children and adolescents. A total of 257 blind children and adolescents (age range: 7–18 years) were examined for autism using a three‐stage process. The first stage estimated probable cases of autistic disorder based on the Autism Behavior Checklist and the second stage by direct observation of the subjects in different settings. In the third stage, subjects with the probable diagnosis of autistic disorder were asked to undergo psychiatric examination. A final diagnosis of autistic disorder (based on the criteria in DSM‐IV) was given after interviewing the caregivers and clinical observation. Thirty of 257 subjects met the criteria for autistic disorder. Comparison of the characteristics of the two groups (autistic and non‐autistic) with χ2‐squared and independent samplet‐tests revealed a statistically significant difference in terms of severity of blindness (P = 0.015), cerebral palsy (P = 0.02) and intellectual level (P = 0.001). The results of the present study suggest that subjects with blindness plus autism have greater neurological impairment (as suggested by the presence of lower intellectual level and cerebral palsy), and more severe visual impairment than the subjects with blindness only.
Relationship between personality disorder symptoms and temperament in the young male general population of South Korea
Authors: HA JEE HYUN , KIM EUNG JO , ABBEY SUSAN E. , KIM TAE‐SUK
Published: January 2007

Abstract  The aim of the present study was to identify the characteristics of temperament and character in personality disorder symptoms in the young male general population. A total of 585 male subjects from the same community were included in the study (mean age, 19.06 ± 0.26 years). There was no difference in socioeconomic and educational background. Subjects completed the Personality Disorder Questionnaire‐IV+ (PDQ‐IV+) and Temperament and Character Inventory (TCI). There were unique correlations between each personality disorder symptom and four temperament profiles. When classification was done through three cluster symptoms by DSM‐IV, cluster A symptoms were most strongly associated with low reward dependence (r = −0.46), cluster B with high novelty seeking (r = 0.33), and cluster C with high harm avoidance (r = 0.47). The character dimension, self‐directedness was the most powerful predictor of the presence of any personality disorders. In homogenous male general population, unique combinations were found between temperament and each personality disorders. Although the subjects were relatively young and therefore their characters had not yet fully matured, character played an important role in the presence of personality disorder. Temperament can be used to differentiate the personality symptoms and characters used to predict the presence of personality disorder.
Reliability and validity of the Japanese version of the Frontal Assessment Battery in patients with the frontal variant of frontotemporal dementia
Authors: NAKAAKI SHUTARO , MURATA YOSHIE , SATO JUNKO , SHINAGAWA YOSHIHIRO , MATSUI TERUO , TATSUMI HIROSHI , FURUKAWA TOSHI A.
Published: January 2007

Abstract  Patients with the frontal variant of frontotemporal dementia (fv‐FTD) exhibit deficits of executive functions. However, no single executive function task that might be used to detect the executive function deficits in fv‐FTD patients has been established as yet. The frontal assessment battery (FAB) devised by Dubois et al. (2000) has been reported to be a quick and simple bedside screening test that is sensitive for differentiating between FTD and Alzheimer’s disease (AD). The present study was conducted with the aim of ascertaining the reliability and validity of the Japanese version of the FAB among Japanese patients with fv‐FTD. The Japanese version of FAB was given to patients with mild fv‐FTD (n = 18) and those with AD (n = 18). The test–retest reliability was evaluated after a 3‐week interval by the same interviewer. Data from the Wisconsin Card Sorting Test (Keio version: KWCST) were also collected to ascertain the validity of the FAB. The Japanese version of the FAB exhibited good internal reliability (Cronbach’s α: 0.70, 95% confidence interval [CI] = 0.50–0.84) and good test–retest reliability (intraclass correlation coefficient: 0.89, 95%CI = 0.77–0.95). Significant correlations were observed between the total FAB score and the category achieved (r = 0.454, P < 0.05) and number of perseveration errors (number of errors that were perseverations; r = 0.719, P < 0.01) in the KWCST. A cut‐off of 10 for the total FAB score yielded the highest sensitivity (85%) and specificity (92%) for discriminating between patients with fv‐FTD and AD with the highest positive likelihood (12.0, 95%CI = 2.6–55.4). The Japanese version of the FAB offers promise as an easy and quick bedside screening test to distinguish fv‐FTD from AD.
Cognitive and symptom profiles in Asperger’s syndrome and high‐functioning autism
Authors: KOYAMA TOMONORI , TACHIMORI HISATERU , OSADA HIROKAZU , TAKEDA TOSHINOBU , KURITA HIROSHI
Published: January 2007

Abstract  Asperger syndrome (AS) and autistic disorder are two subtypes of pervasive developmental disorders (PDD), but there has been considerable debate over whether AS and autistic disorder without mental retardation (IQ ≥ 70), called high‐functioning autism (HFA), are distinct conditions or not. The aim of the present paper was to clarify this issue through a comparison of cognitive function and autistic symptom profiles. Based on the DSM‐IV and ICD‐10 definitions of language acquisition, 36 age‐ and IQ‐balanced subjects with AS (mean age, 12.8 years; mean full‐scale IQ, 98.3) were compared with 37 subjects with HFA (mean age, 12.6 years; mean full‐scale IQ, 94.6) on the Japanese version of the Wechsler Intelligence Scales and the Childhood Autism Rating Scale‐Tokyo Version (CARS‐TV). Compared with the HFA subjects, the AS subjects scored significantly higher on Verbal IQ, Vocabulary, and Comprehension, but scored significantly lower on Coding. Although the total CARS‐TV score did not differ significantly between the two groups, AS subjects scored significantly lower (i.e. less abnormal) on Verbal communication and Non‐verbal communication than did the HFA subjects. A history of normal language acquisition in early childhood could predict his/her better verbal ability in mid‐childhood or later. Autistic cognitive characteristics shared by both AS and HFA subjects appear to support the validity of the current diagnostic classification of PDD.
Reliability and validity of the Japanese version of the World Health Organization‐Five Well‐Being Index in the context of detecting depression in diabetic patients
Authors: AWATA SHUICHI , BECH PER , YOSHIDA SUMIKO , HIRAI MASASHI , SUZUKI SUSUMU , YAMASHITA MOTOYASU , OHARA ARIHISA , HINOKIO YOSHINORI , MATSUOKA HIROO , OKA YOSHITOMO
Published: January 2007

Abstract  The present study had two aims. The first was to evaluate the reliability and the validity of the Japanese version of the World Health Organization (WHO)‐Five Well‐Being Index (WHO‐5‐J) as a brief well‐being scale. The second was to examine the discriminatory validity of this test as a screening tool for current depressive episodes in diabetic patients. A sample of 129 diabetic patients completed the WHO‐5‐J. Of these, 65 were also interviewed by psychiatrists to assess whether they had any current depressive episodes according to DSM‐IV. The internal consistency was evaluated using Cronbach’s alpha, the Loevinger coefficient of homogeneity, and factor analysis. The external concurrent validity was evaluated by correlations with the external scales potentially related to subjective well‐being. Discriminatory validity was evaluated using receiver operating characteristic (ROC) analysis. Cronbach’s alpha and the Loevinger coefficient were estimated to be 0.89 and 0.65, respectively. A factor analysis identified only one factor. The WHO‐5‐J was significantly correlated with a number of major diabetic complications, depression, anxiety, and subjective quality of life. ROC analysis showed that the WHO‐5‐J can be used to detect a current depressive episode (area under curve: 0.92; 95% confidence interval: 0.85–0.98). A cut‐off of <13 yielded the best sensitivity/specificity trade‐off: sensitivity, 100%; specificity, 78%. The WHO‐5‐J was thus found to have a sufficient reliability and validity, indicating that it is a useful instrument for detecting current depressive episodes in diabetic patients.
Cluster A personality disorders: Considering the ‘odd‐eccentric’ in psychiatric nursing
Authors: Hayward Brent A.
Published: January 2007

ABSTRACT:  Psychiatric nurses are familiar with the concept of personality disorder because of their contact with persons with the most common personality disorder in clinical settings – borderline type, who frequently engage mental health services. Perhaps it is this familiarity that has focused research and clinical attention on borderline personality disorder compared with the other personality disorders. The significance of cluster A personality disorders for nursing is multifaceted because of their severity, prevalence, inaccurate diagnosis, poor response to treatment, and similarities to axis I diagnoses. Despite this, literature reviews have established that relatively few studies have focused on the treatment of the cluster A personality disorders – paranoid, schizotypal, and schizoid – resulting in a dearth of evidence‐based interventions for this group of clients. A discussion of these disorders in the context of personality disorder and their individual characteristics demonstrates the distinctive and challenging engagement techniques required by psychiatric nurses to provide effective treatment and care. It is also strongly indicated that the discipline of psychiatric nursing has not yet begun to address the care of persons with cluster A personality disorders.
Evaluation of a forensic psychiatric setting to provide a graduate nurse programme
Authors: Martin Trish , Donley Mandy , Parkes Jordan , Wilkins Cara F.
Published: January 2007

ABSTRACT:  There has been growth in the number and diversity of models of Australian graduate nurse programmes in psychiatric nursing. Programmes have also been established in specialist areas, and evidence is needed regarding best models of graduate nurse programmes and the ability of specialist areas to prepare nurses for psychiatric nursing. This paper reports on a qualitative project that examined the adequacy of a forensic psychiatric hospital to provide a graduate nurse programme. Individual, semistructured interviews were undertaken with nurses participating in the programme, and nurses who had completed the programme and had remained at the hospital or were nursing in other areas. Participants identified that the environment was safe and supportive of professional practice and development, and that skilled nurses were willing to encourage and teach graduates. Processes such as orientation, preceptorship and academic study were appreciated; however, their colleagues’ willingness to be available, to teach, and to support were more valued. Participants reported that they felt confident and prepared as psychiatric nurses. Although limitations of undertaking a graduate nurse programme in a forensic setting were identified, the participants from past programmes who had gone on to work in other services did not report that their nursing careers had been disadvantaged. It can be concluded that as long as the context of the programme has adequate resources to support and assist graduates to develop the skills, knowledge and attitudes of psychiatric nursing, then the specialist nature may not be a limitation.
Insulin‐like growth factor I (IGF‐I) and its receptor (IGF‐1R) in the rat anterior pituitary
Authors: Eppler Elisabeth , Jevdjovic Tanja , Maake Caroline , Reinecke Manfred
Published: January 2007

Few and controversial results exist on the cellular sites of insulin‐like growth factor (IGF)‐I synthesis and the type 1 IGF receptor (IGF‐1R) in mammalian anterior pituitary. Thus, the present study analysed IGF‐I and the IGF‐1R in rat pituitary. Reverse transcription‐polymerase chain reaction revealed IGF‐I and IGF‐1R mRNA expression in pituitary. The sequences of both were identical to the corresponding sequences in other rat organs. In situ hybridization localized IGF‐I mRNA in endocrine cells. The majority of the growth hormone (GH) cells and numerous adrenocorticotropic hormone (ACTH) cells exhibited IGF‐1R‐immunoreactivity at the cell membrane. At lower densities, IGF‐1 receptors were also present at the other hormone‐producing cell types, indicating a physiological impact of IGF‐I for all endocrine cells. IGF‐I‐immunoreactivity was located constantly in almost all ACTH‐immunoreactive cells. At the ultrastructural level, IGF‐I‐immunoreactivity was confined to secretory granules in co‐existence with ACTH‐immunoreactivity, indicating a concomitant release of both hormones. Occasionally, IGF‐I‐immunoreactivity was detected in an interindividually varying number of GH cells. In some individuals, weak IGF‐I‐immunoreactions were also detected also in follicle‐stimulating hormone and luteinizing hormone cells. Thus, IGF‐I seems to be produced as a constituent in ACTH cells, possibly indicating its particular importance in stress response. Generally, IGF‐I from the endocrine cells may regulate synthesis and/or release of hormones in an autocrine/paracrine manner as well as prevent apoptosis and stimulate proliferation. Production of IGF‐I in GH cells may depend on the physiological status, most likely the serum IGF‐I level. IGF‐I released from GH cells may suppress GH synthesis and/or release by an autocrine feedback mechanism in addition to the endocrine route.
Deep brain stimulation in a rat model modulates TH, CaMKIIa and Homer1 gene expression
Authors: Henning Jeannette , Koczan Dirk , Glass Änne , Karopka Thomas , Pahnke Jens , Rolfs Arndt , Benecke Reiner , Gimsa Ulrike
Published: January 2007

High‐frequency stimulation (HFS) of subthalamic nucleus (STN) is a therapy for late‐stage Parkinson's disease. Its mechanisms of action are not yet fully understood. In the present study, gene expression analyses were performed in a rat model of Parkinson's disease, i.e. striatal 6‐hydroxydopamine (6‐OHDA) lesion. Using microarrays, gene expression was analysed in 1‐mm‐thick sagittal brain slices, including basal ganglia of five groups of male Wistar rats. These were unmanipulated rats (group A), unlesioned rats with implanted electrode but without stimulation (group B), unlesioned, stimulated rats (group C), 6‐OHDA‐lesioned rats with implanted electrode but without stimulation (group D), and finally 6‐OHDA‐lesioned and stimulated rats (group E). A statistically significant downregulation of tyrosine hydroxylase (TH) mRNA expression induced by 6‐OHDA lesion and an HFS‐induced TH upregulation in 6‐OHDA‐lesioned rats could be detected. It could be hypothesized that the HFS‐induced upregulation of TH is the result of neuronal STN modulation and mediated via projections from STN to substantia nigra pars compacta. Furthermore, a downregulation of calcium/calmodulin‐dependent protein kinase type IIA and Homer1 was observed. This downregulation could result in a reduced sensitivity towards glutamate in basal ganglia downstream of STN.
Concomitant short‐ and long‐duration response to levodopa in the 6‐OHDA‐lesioned rat: a behavioural and molecular study
Authors: Marin C. , Aguilar E. , Mengod G. , Cortés R. , Obeso J. A.
Published: January 2007

The long‐duration response (LDR) is a sustained improvement in parkinsonism due to chronic levodopa therapy and lasts after discontinuation of treatment. We have investigated the molecular changes that underlie the LDR in rats with a unilateral 6‐hydroxydopamine (6‐OHDA) lesion. Animals were treated for 22 days with levodopa or saline. Forelimb akinesia was evaluated prior and following a test dose of levodopa. Rotational behaviour was weekly evaluated. Levodopa induced an improvement in the parkinsonian limb akinesia that lasted for 48 h after withdrawal. A shortening in the duration of rotational behaviour was observed. After 3 days of washout, levodopa treatment maintained elevated striatal preproenkephalin mRNA expression, also inducing an increase in preprodynorphin (PDyn) and dopamine D‐3 receptor mRNAs, but without any modification of the adenosine A2A mRNA expression induced by 6‐OHDA. Levodopa reversed the lesion‐induced increase in the expression of cytochrome oxidase mRNA in the subthalamic nucleus and glutamate decarboxylase mRNA in the pars reticulata of the substantia nigra. After 7 days of levodopa washout, the molecular markers show a decline in the basal ganglia evolving towards the parkinsonian state, being statistically significant for the striatal PDyn mRNA. This study characterizes the concomitant presence of the short‐duration response and LDR to levodopa in the 6‐OHDA model of parkinsonism and shows that the molecular changes induced by levodopa in the basal ganglia are not permanent and that this reversal after levodopa washout may be responsible for the gradual motor deterioration that characterize the LDR.
Environmental enrichment enhances neurogenesis and improves functional outcome after cranial irradiation
Authors: Fan Yang , Liu Zhengyan , Weinstein Philip R. , Fike John R. , Liu Jialing
Published: January 2007

Radiation therapy is a widely used treatment for brain tumors but it can cause delayed progressive cognitive decline and memory deficits. Previous studies suggested that this neurocognitive dysfunction might be linked to the impairment of hippocampal neurogenesis. However, little is known regarding how to reduce the cognitive impairment caused by radiation therapy. To investigate whether environmental enrichment (EE) promotes neurogenesis and cognitive function after irradiation, irradiated gerbils were housed in EE for 2 months and evaluated by neurobehavioral testing for learning and memory function, and immunohistochemical analysis for neurogenesis. Our results demonstrated that even relatively low doses (5–10 Gy) of irradiation could acutely abolish precursor cell proliferation in the dentate gyrus by more than 90%. This reduction in precursor proliferation was persistent and led to a significant decline in the granule cell population 9 months later. EE housing enhanced the number of newborn neurons and increased residual neurogenesis. EE also significantly increased the total number of immature neurons in the dentate gyrus. Furthermore, irradiated animals after EE housing showed a significant improvement in spatial learning and memory during the water‐maze test and in rotorod motor learning over a 5‐day training paradigm. In conclusion, EE has a positive impact on hippocampal neurogenesis and functional recovery in irradiated adult gerbils. Our data suggest that there is still a considerable amount of plasticity remaining in the hippocampal progenitor cells in adult animals after radiation injury, which can become a target of therapeutic intervention for radiation‐induced cognitive dysfunction.
Local administration of N‐acetylaspartylglutamate (NAAG) peptidase inhibitors is analgesic in peripheral pain in rats
Authors: Yamamoto Tatsuo , Saito Osamu , Aoe Tomohiko , Bartolozzi Alessandra , Sarva Jayaprakash , Zhou Jia , Kozikowski Alan , Wroblewska Barbara , Bzdega Tomasz , Neale Joseph H.
Published: January 2007

The peptide neurotransmitter N‐acetylaspartylglutamate (NAAG) selectively activates group II metabotropic glutamate receptors (mGluRs). Systemic administration of inhibitors of the enzymes that inactivate NAAG results in decreased pain responses in rat models of inflammatory and neuropathic pain. These effects are blocked by a group II mGluR antagonist. This research tested the hypothesis that some analgesic effects of NAAG peptidase inhibition are mediated by NAAG acting on sensory neurite mGluRs at the site of inflammation. Group II mGluR agonists, SLx‐3095‐1, NAAG and APDC, or NAAG peptidase inhibitors, ZJ‐43 and 2‐PMPA, injected into the rat footpad reduced pain responses in carrageenan or formalin models. The analgesic effects of SLx‐3095‐1, APDC, ZJ‐43, 2‐PMPA and NAAG were blocked by co‐injection of LY341495, a selective group II mGluR antagonist. Injection of group II mGluR agonists, NAAG or the peptidase inhibitors into the contralateral rat footpad had no effect on pain perception in the injected paw. At 10–100 µm ZJ‐43 and 2‐PMPA demonstrated no consistent agonist activity at mGluR2 or mGluR3. Consistent with the conclusion that peripherally administered NAAG peptidase inhibitors increase the activation of mGluR3 by NAAG that is released from peripheral sensory neurites, we found that the tissue average concentration of NAAG in the unstimulated rat hind paw was about 6 µm. These data extend our understanding of the role of this peptide in sensory neurons and reveal the potential for treatment of inflammatory pain via local application of NAAG peptidase inhibitors at doses that may have little or no central nervous system effects.
Low‐frequency stimulation of the direct cortical input to area CA1 induces homosynaptic LTD and heterosynaptic LTP in the rat hippocampal–entorhinal cortex slice preparation
Authors: Wöhrl Robert , Von Haebler Dorothea , Heinemann Uwe
Published: January 2007

The entorhinal cortex (EC) innervates area CA1 and the subiculum directly via the portion of the perforant path, which originates from EC layer III cells referred to as direct cortical input (dCI), and indirectly via the trisynaptic loop through the dentate gyrus and area CA3. The dCI is of great importance as it mediates positional information for activation of place cells that is not prevented after interrupting information flow from area CA3 to CA1. In this study, we investigated the effects of low‐frequency stimulation of the dCI on homo‐ and heterosynaptic plasticity in area CA1 and tested for the contribution of NMDA, GABAA, GABAB, kainate and group I mGlu receptors. We demonstrate that 1 Hz stimulation of the dCI induces homosynaptic long‐term depression (LTD) and that 1 Hz stimulation of the dCI induces a long‐lasting augmentation of stratum radiatum‐induced population spikes in area CA1 (heterosynaptic long‐term potentiation). Additionally we show that homosynaptic effects depend on activation of GABAB and kainate receptors, whereas the heterosynaptic effects are GABAA and mGlu receptor dependent.
Changes in blood–brain barrier permeability to large and small molecules following traumatic brain injury in mice
Authors: Habgood M. D. , Bye N. , Dziegielewska K. M. , Ek C. J. , Lane M. A. , Potter A. , Morganti‐Kossmann C , Saunders N. R.
Published: January 2007

The entry of therapeutic compounds into the brain and spinal cord is normally restricted by barrier mechanisms in cerebral blood vessels (blood–brain barrier) and choroid plexuses (blood–CSF barrier). In the injured brain, ruptured cerebral blood vessels circumvent these barrier mechanisms by allowing blood contents to escape directly into the brain parenchyma. This process may contribute to the secondary damage that follows the initial primary injury. However, this localized compromise of barrier function in the injured brain may also provide a ‘window of opportunity’ through which drugs that do not normally cross the blood–brain barriers are able to do so. This paper describes a systematic study of barrier permeability in a mouse model of traumatic brain injury using both small and large inert molecules that can be visualized or quantified. The results show that soon after trauma, both large and small molecules are able to enter the brain in and around the injury site. Barrier restriction to large (protein‐sized) molecules is restored by 4–5 h after injury. In contrast, smaller molecules (286–10 000 Da) are still able to enter the brain as long as 4 days postinjury. Thus the period of potential secondary damage from barrier disruption and the period during which therapeutic compounds have direct access to the injured brain may be longer than previously thought.
Neurochemical identification of stereotypic burst‐firing neurons in the rat dorsal raphe nucleus using juxtacellular labelling methods
Authors: Hajós Mihály , Allers Kelly A. , Jennings Katie , Sharp Trevor , Charette Guy , Sík Attila , Kocsis Bernát
Published: January 2007

Recent electrophysiological studies have discovered evidence of heterogeneity of 5‐hydroxytryptamine (5‐HT) neurons in the mesencephalic raphe nuclei. Of particular interest is a subpopulation of putative 5‐HT neurons that display many of the electrophysiological properties of presumed 5‐HT‐containing neurons (regular and slow firing of single spikes with a broad waveform) but fire spikes in short, stereotyped bursts. In the present study we investigated the chemical identity of these neurons in rats utilizing in vivo juxtacellular labelling methods. Of ten dorsal raphe nucleus (DRN) neurons firing short stereotyped bursts within an otherwise regular firing pattern, all exhibited immunoreactivity for either 5‐HT (n = 6) or the 5‐HT synthesizing enzyme, tryptophan hydroxylase (TRH; n = 2) or both (n = 2). Supporting pharmacological experiments demonstrated that the burst firing DRN neurons demonstrated equal sensitivity to 5‐HT1A agonism and α1‐adrenoceptor antagonism to single spiking DRN neurons that we have previously identified as 5‐HT‐containing. Collectively these data provide direct evidence that DRN neurons that exhibit stereotyped burst firing activity are 5‐HT containing. The presence of multiple types of electrophysiologically distinct midbrain 5‐HT neurons is discussed.
Effects of sex and age on regional prefrontal brain volume in two human cohorts
Authors: Cowell Patricia E. , Sluming Vanessa A. , Wilkinson Iain D. , Cezayirli Enis , Romanowski Charles A. J. , Webb Jocasta A. , Keller Simon S. , Mayes Andrew , Roberts Neil
Published: January 2007

This study examined interactive effects of sex and age on prefrontal brain anatomy in humans. It specifically targeted ranges of the adult life span and regions of cortex that previously showed male–female differences. Participants were 68 healthy human males and females aged 20–72 years. Data collection and analysis were conducted in parallel across two cohorts (laboratories) to investigate reproducibility of effects in relation to sex and age. Volumes for four regional prefrontal subfields per hemisphere were obtained from high‐resolution MRI. Regional sex by age interactions were replicated across cohorts. In men, age effects were greatest in medial prefrontal volume, with decreases in dorsal medial and orbital medial regions. In women, age‐related changes in medial prefrontal regions were limited to the dorsal volume, with additional decreases observed in lateral subfields. Cohort and Cohort × Age effects in total brain and total prefrontal volume were linked to a combination of methodological and sampling‐related factors. Findings indicated that neuroanatomical changes throughout adulthood unfold along different time scales in men and women. Results also showed that sex differences in ageing localized to medial prefrontal regions were particularly robust to variation across cohorts.
A multicopper oxidase is essential for manganese oxidation and laccase‐like activity in Pedomicrobium sp. ACM 3067
Authors: Ridge Justin P. , Lin Marianne , Larsen Eloise I. , Fegan Mark , McEwan Alastair G. , Sly Lindsay I.
Published: January 2007

Pedomicrobium sp. ACM 3067 is a budding‐hyphal bacterium belonging to the α‐Proteobacteria which is able to oxidize soluble Mn2+ to insoluble manganese oxide. A cosmid, from a whole‐genome library, containing the putative genes responsible for manganese oxidation was identified and a primer‐walking approach yielded 4350 bp of novel sequence. Analysis of this sequence showed the presence of a predicted three‐gene operon, moxCBA. The moxA gene product showed homology to multicopper oxidases (MCOs) and contained the characteristic four copper‐binding motifs (A, B, C and D) common to MCOs. An insertion mutation of moxA showed that this gene was essential for both manganese oxidation and laccase‐like activity. The moxB gene product showed homology to a family of outer membrane proteins which are essential for Type I secretion in Gram‐negative bacteria. moxBA has not been observed in other manganese‐oxidizing bacteria but homologues were identified in the genomes of several bacteria including Sinorhizobium meliloti 1021 and Agrobacterium tumefaciens C58. These results suggest that moxBA and its homologues constitute a family of genes encoding an MCO and a predicted component of the Type I secretion system.
Contingency view on technological differentiation and firm performance: evidence in an economic downturn
Authors: Wu Hsueh‐Liang , Lin Bou‐Wen , Chen Chung‐Jen
Published: January 2007

Although the importance of strategy for firm performance has been studied, little evidence has been offered regarding this linkage in hostile environments characterized by a lack of exploitable market opportunity and fiercer competition. This study aims to examine the viability of strategic postures of technological differentiation in such a setting using data from 1,054 samples across 32 industries in 30 countries during 2001–2002, when global economies suffered a downturn. The empirical results show that differentiation‐oriented firms underperformed efficiency‐oriented ones during this period. However, in the face of deteriorating market conditions, a strategic orientation toward technological differentiation, in concert with an internal commitment to R&D investment or external munificence toward technological opportunity, yields better performance. Finally, this study finds that firms with tight coupling between differentiation and efficiency outmaneuver those with a pure strategy or no strategy at the time of an economic downturn.
Effect of Contour Intervals and Grid Cell Size on the Accuracy of DEMs and Slope Derivatives
Authors: Ziadat Feras M
Published: January 2007

Digital Elevation Models (DEMs) are indispensable tools in many environmental and natural resource applications. DEMs are frequently derived from contour lines. The accuracy of such DEMs depends on different factors. This research investigates the effect of sampling density used to derive contours, vertical interval between contours (spacing), grid cell size of the DEM (resolution), terrain complexity, and spatial filtering on the accuracy of the DEM and the slope derivative. The study indicated different alternatives to achieve an acceptable accuracy depending on the contour interval, the DEM resolution and the complexity of the terrain. The effect of these factors on the accuracy of the DEM and the slope derivative was quantified using models that determine the level of accuracy (RMSE). The implementation of the models will guide users to select the best combination to improve the results in areas with similar topography. For areas with variable terrain complexity, the suggestion is to generate DEMs and slope at a suitable resolution for each terrain separately and then to merge the results to produce one final layer for the whole area. This will provide accurate estimates of elevation and slope, and subsequently improve the analyses that rely on these digital derivatives.
Ontological Engineering for Interpreting Geospatial Queries
Authors: Peachavanish Ratchata , Karimi Hassan A
Published: January 2007

Despite advancements in geographic information system (GIS) technology, the efficient and effective utilization of GIS to solve geospatial problems is a daunting process requiring specialized knowledge and skills. Two of the most important and burdensome tasks in this process are interpretation of geospatial queries and mapping the interpreted results into geospatial data models and geoprocessing operations. With the current state of GIS, there exists a gap between the knowledge user's possess and the knowledge and skills they need to utilize GIS for solving problems. Currently, users resort to training and practice on GIS technology or involving GIS experts. Neither of these options is optimal and there is a need for a new approach that automates geoprocessing tasks using GIS technology. This paper presents an ontological engineering methodology that uses multiple ontologies and the mappings among them to automate certain tasks related to interpretation of geospatial queries and mapping the interpreted results into geospatial data models and geoprocessing operations. The presented methodology includes conceptualization of geospatial queries, knowledge representation for queries, techniques for relating elements in different ontologies, and an algorithm that uses ontologies to map queries to geoprocessing operations.
Empirical-Likelihood-Based Inference in Missing Response Problems and Its Application in Observational Studies
Authors: Qin Jing , Zhang Biao
Published: January 2007

The problem of missing response data is ubiquitous in medical and social science studies. In the case of responses that are missing at random (depending on some covariate information), analyses focused only on the complete data may lead to biased results. Various debias methods have been extensively studied in the literature, particularly the weighting method that was motivated by Horvitz and Thompson's estimators. To improve efficiency, Robins, Rotnitzky and Zhao proposed augmented estimating equations based on corrected complete-case analyses. A nice feature of the augmented method is its ‘double robustness’, i.e. the estimator that is derived from the augmented method is asymptotically unbiased if either the underlying missing data mechanism or the underlying regression function is correctly specified. Furthermore, the augmented estimator can achieve full efficiency if both the missing data mechanism and the regression function are correctly specified. In general, however, it is very difficult to specify the regression function correctly, especially when the dimension of covariates is high— this is the so-called curse of dimensionality problem. The augmented estimator has much lower efficiency if the ‘working regression model’ is not close to the true regression model. In this paper, the empirical likelihood method is employed to seek a constrained empirical likelihood estimation of mean response with the assumption that responses are missing at random. The empirical-likelihood-based estimators enjoy the double-robustness property. Moreover, it is possible that the empirical-likelihood-based inference can produce asymptotically unbiased and efficient estimators even if the true regression function is not completely known. Simulation results indicate that the empirical-likelihood-based estimators are very robust to a misspecification of the propensity score and dominate other competitors in the sense of having smaller mean-square errors. Methods that are developed in this paper have a nice application in observational causal inferences. The propensity score is used to adjust for differences in pretreatment variables in the estimation of average treatment effects.
IGF‐I‐induced oligodendrocyte progenitor proliferation requires PI3K/Akt, MEK/ERK, and Src‐like tyrosine kinases
Authors: Cui Qiao‐Ling , Almazan Guillermina
Published: January 2007

Insulin‐like growth factor‐I (IGF‐I) is required for the growth of oligodendrocytes, although the underlying mechanisms are not fully understood. Our aim was to investigate the role of phosphatidylinositol 3‐kinase (PI3K), mitogen‐activated protein kinase kinase (MEK1), and Src family tyrosine kinases in IGF‐I‐stimulated proliferation of oligodendrocyte progenitors. IGF‐I treatment increased the proliferation of cultured oligodendrocyte progenitors as determined by measuring incorporation of [3H]‐thymidine and bromodeoxy‐uridine (BrdU). IGF‐I stimulated a transient phosphorylation of 3‐phosphoinositide‐dependent kinase‐1 (PDK1) and extracellular signal‐regulated kinases (ERK1/2) (targets of MEK1), as well as a rapid and sustained activation of Akt (a target of PI3K). Furthermore, inhibitors of PI3K (LY294002 and Wortmannin), MEK1 (PD98059 and U0126), and Src family tyrosine kinases (PP2) decreased IGF‐I‐induced proliferation, and blocked ERK1/2 activation. LY294002, Wortmannin and PP2 also blocked Akt activation. To further determine whether Akt is required for IGF‐I stimulated oligodendrocyte progenitor proliferation, cultures were infected with adenovirus vectors expressing dominant‐negative mutants of Akt or treated with pharmacological inhibitors of Akt. All treatments reduced IGF‐I‐induced oligodendrocyte progenitor proliferation. Our data indicate that stimulation of oligodendrocyte progenitor proliferation by IGF‐I requires Src‐like tyrosine kinases as well as the PI3K/Akt and MEK1/ERK signaling pathways.
Purification of visual arrestin from squid photoreceptors and characterization of arrestin interaction with rhodopsin and rhodopsin kinase
Authors: Swardfager Walter , Mitchell Jane
Published: January 2007

Invertebrate visual signal transduction involves photoisomerization of rhodopsin, activating a guanine nucleotide binding protein (G protein) of the Gq class, iGq, which stimulates a phospholipase C, increasing intracellular Ca2+. Arrestin binding to photoactivated rhodopsin is a key mechanism of desensitization. We have previously reported the cloning of a retina‐specific arrestin cDNA from Loligo pealei displaying 56–64% sequence similarity to other reported arrestin sequences. Here, we report the purification of the 55‐kDa squid visual arrestin. Purified squid visual arrestin is able to inhibit light‐activated GTPase activity dose‐dependently in arrestin‐depleted rhabdomeric membranes and associate with the membrane in a light‐dependent manner. Membrane association can be partially inhibited by inositol 1,2,3,4,5,6‐hexakisphosphate (IP6), a soluble analog of the membrane lipid phosphatidylinositol 3,4,5‐triphosphate. In reconstitution assays, we demonstrate arrestin phosphorylation by squid rhodopsin kinase, a novel function among the G protein‐coupled receptor kinase family. Phosphorylation of purified arrestin requires squid rhodopsin kinase, membranes, light‐activation, and the presence of Ca2+. This is the first large‐scale purification of an invertebrate arrestin and biochemical demonstration of arrestin function in the invertebrate visual system.
Role of quaternary ammonium salts in improving the fastness properties of anionic dyes on cellulose fibres
Authors: Sharif Saima , Ahmad Saeed , Izhar‐ul‐Haq Mian Muhammad
Published: January 2007

The object of this study was to review the developments taking place during 1990–2005 regarding the use of quaternary ammonium salts as dye fixing agents for improving the fastness properties of anionic dyes on cellulose fibres. As far as fastness properties are concerned, this review is restricted only to fastness to light, washing and water treatments.
Biogeographic Biases in Research and Their Consequences for Linking Amphibian Declines to Pollution
Authors: SCHIESARI LUIS , GRILLITSCH BRITTA , GRILLITSCH HEINZ
Published: January 2007

Abstract: The collapse of amphibian populations within pristine reserves worldwide suggests that diffuse, globally distributed factors such as pollution may be a cause of these declines. Nevertheless, cause–effect relationships between pollution and declines have proven difficult to establish at all scales, from local to global. We therefore aimed to quantitatively evaluate the weight of evidence for the role of pollution in global amphibian declines by first quantifying the published research on the effects of pollutants for all amphibian species in the world and then cross‐referencing this information with species' biogeographic distribution, range area, and conservation status and with threats to species as summarized in the Global Amphibian Assessment. We found strong biogeographic and related taxonomic research biases, with a few, common, widely distributed generalist species from the northern hemisphere accounting for the majority of studies. Tropical regions, where more species and declines occur, were severely underrepresented in ecotoxicological research; therefore, current knowledge does not permit assessment of the significance of pollution in amphibian declines at a global scale or in regions where most declines occur. Moreover, if broader distributional ranges and occurrence at higher latitudes are correlated with broader environmental tolerances, current knowledge may considerably underestimate the sensitivity of the majority of amphibian species to pollutants. Finally, because species studied represent only a narrow subset of traits that mediate exposure and susceptibility to pollution, the current potential for extrapolation among species, guilds, ontogenetic phases, levels of complexity, habitat types, sites, and regions is weak. Ultimately, to mitigate these research biases and thus improve the basis for risk management, research policy must balance the spatial scale of the problem (global) and the distribution of knowledge (regional) so that biodiversity representation can be increased and regional bioindicators of environmental health can be developed.