bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of NaCl concentration and pH on the stability of hyperthermophilic protein Ssh10b
Authors: Mao Yong-Jin , Sheng Xiang-Rong , Pan Xian-Ming
Published: December 2007

Background

Hyperthermophiles constitute a group of microorganisms with an optimum growth temperature of between 80°C and 100°C. Although the molecular underpinnings of protein thermostabilization have been the focus of many theoretical and experimental efforts, the properties leading to the higher denaturation temperature of hyperthermophilic proteins are still controversial. Among the large number of factors identified as responsible for the thermostability of hyperthermophilic proteins, the electrostatic interactions are thought to be a universally important factor.

Results

In this study, we report the effects of pH and salt concentration on the urea-induced denaturation of the protein Ssh10b from a hyperthermophile in low ionic strength buffer. In the absence of NaCl, the unfolding ΔG of the protein increased from about 33 kJ/mol at pH 3 to about 78 kJ/mol at pH 10. At all values of pH, the ΔG increased with increasing NaCl concentration, indicating that salt stabilizes the protein significantly.

Conclusion

These findings suggests that the increased number of charged residues and ion pairs in the protein Ssh10b from hyperthermophiles does not contribute to the stabilization of the folded protein, but may play a role in determining the denatured state ensemble and also in increasing the denaturation temperature.
A mixture of feature experts approach for protein-protein interaction prediction
Authors: Qi Yanjun , Klein-Seetharaman Judith , Bar-Joseph Ziv
Published: December 2007

Background

High-throughput methods can directly detect the set of interacting proteins in model species but the results are often incomplete and exhibit high false positive and false negative rates. A number of researchers have recently presented methods for integrating direct and indirect data for predicting interactions. These methods utilize a common classifier for all pairs. However, due to missing data and high redundancy among the features used, different protein pairs may benefit from different features based on the set of attributes available. In addition, in many cases it is hard to directly determine which of the data sources contributed to a prediction. This information is important for biologists using these predications in the design of new experiments.

Results

To address these challenges we propose a Mixture-of-Feature-Experts method for protein-protein interaction prediction. We split the features into roughly homogeneous sets of feature experts. The individual experts use logistic regression and their scores are combined using another logistic regression. When combining the scores the weighting of each expert depends on the set of input attributes available for that pair. Thus, different experts will have different influence on the prediction depending on the available features.

Conclusion

We applied our method to predict the set of interacting proteins in yeast and human cells. Our method improved upon the best previous methods for this task. In addition, the weighting of the experts provides means to evaluate the prediction based on the high scoring features.
Accurate splice site prediction using support vector machines
Authors: Sonnenburg Sören , Schweikert Gabriele , Philips Petra , Behr Jonas , Rätsch Gunnar
Published: December 2007

Background

For splice site recognition, one has to solve two classification problems: discriminating true from decoy splice sites for both acceptor and donor sites. Gene finding systems typically rely on Markov Chains to solve these tasks.

Results

In this work we consider Support Vector Machines for splice site recognition. We employ the so-called weighted degree kernel which turns out well suited for this task, as we will illustrate in several experiments where we compare its prediction accuracy with that of recently proposed systems. We apply our method to the genome-wide recognition of splice sites in Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana, Danio rerio, and Homo sapiens. Our performance estimates indicate that splice sites can be recognized very accurately in these genomes and that our method outperforms many other methods including Markov Chains, GeneSplicer and SpliceMachine. We provide genome-wide predictions of splice sites and a stand-alone prediction tool ready to be used for incorporation in a gene finder.

Availability

Data, splits, additional information on the model selection, the whole genome predictions, as well as the stand-alone prediction tool are available for download at http://www.fml.mpg.de/raetsch/projects/splice.
The expression of HSP27 is associated with poor clinical outcome in intrahepatic cholangiocarcinoma
Authors: Romani Antonello A , Crafa Pellegrino , Desenzani Silvia , Graiani Gallia , Lagrasta Costanza , Sianesi Mario , Soliani Paolo , Borghetti Angelo F
Published: December 2007

Background

The heat shock proteins (HSPs) 27-kDa (HSP27) and 72-kDa (HSP72), are ubiquitous chaperone molecules inducible in cells exposed to different stress conditions. Increased level of HSPs are reported in several human cancers, and found to be associated with the resistance to some anticancer treatments and poor prognosis. However, there is no study of the relationship between HSPs expression and patient's prognosis in intrahepatic cholangiocarcinoma (IHCCA). In this exploratory retrospective study, we investigated the expressions of HSP27 and HSP72 as potential prognostic factors in IHCCA.

Methods

Thirty-one paraffin-embedded samples were analyzed by immunohistochemical methods using HSP27 and HSP72 monoclonal antibodies. Proliferation rate was assessed in the same specimens by using monoclonal antibody against phosphorylated histone H3 (pHH3). Fisher's exact test was used to assess the hypothesis of independence between categorical variables in 2 × 2 tables. The ANOVA procedure was used to evaluate the association between ordinal and categorical variables. Estimates of the survival probability were calculated using the Kaplan-Meier method, and the log rank test was employed to test the null hypothesis of equality in overall survival among groups. The hazard ratio associated with HSP27 and HSP72 expression was estimated by Cox hazard-proportional regression.

Results

The expression of HSP27 was related to mitotic index, tumor greatest dimension, capsular and vascular invasion while the expression of HSP72 was only related to the presence of necrosis and the lymphoid infiltration. Kaplan-Maier analysis suggested that the expression of HSP27 significantly worsened the patients' median overall survival (11 ± 3.18 vs 55 ± 4.1 months, P-value = 0.0003). Moreover HSP27-positive patients exhibited the worst mean survival (7.0 ± 3.2 months) in the absence of concomitant HSP72 expression.

Conclusion

The expression of HSP27, likely increasing cell proliferation, tumor mass, vascular and capsular invasion, might promote aggressive tumor behaviour in IHCCA and decrease patients' survival. Immunohistochemical detection of HSP27 on routine sections may provide a reliable prognostic marker for IHCCA able to influence the therapeutic strategies for this cancer.
Correlation between the progressive cytoplasmic expression of a novel small heat shock protein (Hsp16.2) and malignancy in brain tumors
Authors: Pozsgai Eva , Gomori Eva , Szigeti Andras , Boronkai Arpad , Gallyas Ferenc , Sumegi Balazs , Bellyei Szabolcs
Published: December 2007

Background

Small heat shock proteins are molecular chaperones that protect proteins against stress-induced aggregation. They have also been found to have anti-apoptotic activity and to play a part in the development of tumors. Recently, we identified a new small heat shock protein, Hsp16.2 which displayed increased expression in neuroectodermal tumors. Our aim was to investigate the expression of Hsp16.2 in different types of brain tumors and to correlate its expression with the histological grade of the tumor.

Methods

Immunohistochemistry with a polyclonal antibody to Hsp16.2 was carried out on formalin-fixed, paraffin-wax-embedded sections using the streptavidin-biotin method. 91 samples were examined and their histological grade was defined. According to the intensity of Hsp16.2 immunoreactivity, low (+), moderate (++), high (+++) or none (-) scores were given.

Immunoblotting was carried out on 30 samples of brain tumors using SDS-polyacrylamide gel electrophoresis and Western-blotting.

Results

Low grade (grades 1–2) brain tumors displayed low cytoplasmic Hsp16.2 immunoreactivity, grade 3 tumors showed moderate cytoplasmic staining, while high grade (grade 4) tumors exhibited intensive cytoplasmic Hsp16.2 staining. Immunoblotting supported the above mentioned results. Normal brain tissue acted as a negative control for the experiment, since the cytoplasm did not stain for Hsp16.2. There was a positive correlation between the level of Hsp16.2 expression and the level of anaplasia in different malignant tissue samples.

Conclusion

Hsp16.2 expression was directly correlated with the histological grade of brain tumors, therefore Hsp16.2 may have relevance as becoming a possible tumor marker.
Using machine learning algorithms to guide rehabilitation planning for home care clients
Authors: Zhu Mu , Zhang Zhanyang , Hirdes John P , Stolee Paul
Published: December 2007

Background

Targeting older clients for rehabilitation is a clinical challenge and a research priority. We investigate the potential of machine learning algorithms – Support Vector Machine (SVM) and K-Nearest Neighbors (KNN) – to guide rehabilitation planning for home care clients.

Methods

This study is a secondary analysis of data on 24,724 longer-term clients from eight home care programs in Ontario. Data were collected with the RAI-HC assessment system, in which the Activities of Daily Living Clinical Assessment Protocol (ADLCAP) is used to identify clients with rehabilitation potential. For study purposes, a client is defined as having rehabilitation potential if there was: i) improvement in ADL functioning, or ii) discharge home. SVM and KNN results are compared with those obtained using the ADLCAP. For comparison, the machine learning algorithms use the same functional and health status indicators as the ADLCAP.

Results

The KNN and SVM algorithms achieved similar substantially improved performance over the ADLCAP, although false positive and false negative rates were still fairly high (FP > .18, FN > .34 versus FP > .29, FN. > .58 for ADLCAP). Results are used to suggest potential revisions to the ADLCAP.

Conclusion

Machine learning algorithms achieved superior predictions than the current protocol. Machine learning results are less readily interpretable, but can also be used to guide development of improved clinical protocols.
Process skill rather than motor skill seems to be a predictor of costs for rehabilitation after a stroke in working age; a longitudinal study with a 1 year follow up post discharge
Authors: Björkdahl Ann , Sunnerhagen Katharina Stibrant
Published: December 2007

Background

In recent years a number of costs of stroke studies have been conducted based on incidence or prevalence and estimating costs at a given time. As there still is a need for a deeper understanding of factors influencing these costs the aim of this study was to calculate the direct and indirect costs in a younger (<65) sample of stroke patients and to explore factors affecting the costs.

Methods

Fifty-eight patients included in a study of home rehabilitation and followed for 1 year after discharge from the rehabilitation unit, were interviewed about their use of health care services, assistance, medications and assistive devices. Costs (defined as the cost for society) were calculated. A linear regression of cost and variables of functioning, ability, community integration and health-related quality of life was done.

Results

Inpatient care contributed substantially to the direct cost with a mean length of stay of 92 days. Rehabilitation during the first year constituted of an average of 28 days in day clinics, 38 physiotherapy sessions and 20 occupational therapy sessions. The total direct mean cost was 80 020 € and the indirect cost 35 129 €. The direct costs were influenced by the process skill (the ability to plan and perform a given task and to adapt when needed) and presence of aphasia. Indirect costs for informal care giving increased for patients with a lower health-related quality of life as well as a low score on home integration.

Conclusion

Costs are high in this group of young (< 65 years) stroke patients compared to other studies, partly due to the length of the stay and partly to loss of productivity.
Obesity and pre-hypertension in family medicine: Implications for quality improvement
Authors: Rohrer James E , Anderson Gregory J , Furst Joseph W
Published: December 2007

Background.

Prevention of pre-hypertension is an important goal for primary care patients. Obesity is a risk factor for hypertension, but has not been addressed for pre-hypertension in primary care populations. The objective of this study was to assess the degree to which obesity independently is associated with risk for pre-hypertension in family medicine patients.

Methods.

This study was a retrospective analysis of information abstracted from medical records of 707 adult patients. Multivariable logistic regression was used to test the relationship between body mass index (BMI) and pre-hypertension, after adjustment for comorbidity and demographic characteristics. Pre-hypertension was defined as systolic pressure between 120 and 139 mm Hg or diastolic pressure between 80 and 89 mm Hg.

Results.

In our sample, 42.9% of patients were pre-hypertensive. Logistic regression analysis revealed that, in comparison to patients with normal body mass, patients with BMI > 35 had higher adjusted odds of being pre-hypertensive (OR = 4.5, CI 2.55–8.11, p < .01). BMI between 30 and 35 also was significant (OR = 2.7, CI 1.61–4.63, p < 0.01) as was overweight (OR = 1.8, CI 1.14–2.92, p = 0.01).

Conclusion.

In our sample of family medicine patients, elevated BMI is a risk factor for pre-hypertension, especially BMI > 35. This relationship appears to be independent of age, gender, marital status and comorbidity. Weight loss intervention for obese patients, including patient education or referral to weight loss programs, might be effective for prevention of pre-hypertension and thus should be considered as a potential quality indicator.
Extensive population genetic structure in the giraffe
Authors: Brown David M , Brenneman Rick A , Koepfli Klaus-Peter , Pollinger John P , Milá Borja , Georgiadis Nicholas J , Louis Edward E , Grether Gregory F , Jacobs David K , Wayne Robert K
Published: December 2007

Background

A central question in the evolutionary diversification of large, widespread, mobile mammals is how substantial differentiation can arise, particularly in the absence of topographic or habitat barriers to dispersal. All extant giraffes (Giraffa camelopardalis) are currently considered to represent a single species classified into multiple subspecies. However, geographic variation in traits such as pelage pattern is clearly evident across the range in sub-Saharan Africa and abrupt transition zones between different pelage types are typically not associated with extrinsic barriers to gene flow, suggesting reproductive isolation.

Results

By analyzing mitochondrial DNA sequences and nuclear microsatellite loci, we show that there are at least six genealogically distinct lineages of giraffe in Africa, with little evidence of interbreeding between them. Some of these lineages appear to be maintained in the absence of contemporary barriers to gene flow, possibly by differences in reproductive timing or pelage-based assortative mating, suggesting that populations usually recognized as subspecies have a long history of reproductive isolation. Further, five of the six putative lineages also contain genetically discrete populations, yielding at least 11 genetically distinct populations.

Conclusion

Such extreme genetic subdivision within a large vertebrate with high dispersal capabilities is unprecedented and exceeds that of any other large African mammal. Our results have significant implications for giraffe conservation, and imply separatein situandex situmanagement, not only of pelage morphs, but also of local populations.
Short-term effects of amelogenin gene splice products A+4 and A-4 implanted in the exposed rat molar pulp
Authors: Jegat Nadège , Septier Dominique , Veis Arthur , Poliard Anne , Goldberg Michel
Published: December 2007

In order to study the short-time effects of two bioactive low-molecular amelogenins A+4 and A-4, half-moon cavities were prepared in the mesial aspect of the first maxillary molars, and after pulp exposure, agarose beads alone (controls) or beads soaked in A+4 or A-4 (experimental) were implanted into the pulp. After 1, 3 or 7 days, the rats were killed and the teeth studied by immunohistochemistry. Cell proliferation was studied by PCNA labeling, positive at 3 days, but decreasing at day 7 for A+4, whilst constantly high between 3 and 7 days for A-4. The differentiation toward the osteo/odontoblast lineage shown by RP59 labeling was more apparent for A-4 compared with A+4. Osteopontin-positive cells were alike at days 3 and 7 for A-4. In contrast, for A+4, the weak labeling detected at day 3 became stronger at day 7. Dentin sialoprotein (DSP), an in vivo odontoblast marker, was not detectable until day 7 where a few cells became DSP positive after A-4 stimulation, but not for A+4. These results suggest that A +/- 4 promote the proliferation of some pulp cells. Some of them further differentiate into osteoblast-like progenitors, the effects being more precocious for A-4 (day 3) compared with A+4 (day 7). The present data suggest that A +/- 4 promote early recruitment of osteogenic progenitors, and evidence functional differences between A+4 and A-4.
Alstrom syndrome (OMIM 203800): a case report and literature review
Authors: Joy Tisha , Cao Henian , Black Graeme , Malik Rayaz , Charlton-Menys Valentine , Hegele Robert A , Durrington Paul N
Published: December 2007

Background

Alstrom syndrome (AS) is a rare autosomal recessive disease characterized by multiorgan dysfunction. The key features are childhood obesity, blindness due to congenital retinal dystrophy, and sensorineural hearing loss. Associated endocrinologic features include hyperinsulinemia, early-onset type 2 diabetes, and hypertriglyceridemia. Thus, AS shares several features with the common metabolic syndrome, namely obesity, hyperinsulinemia, and hypertriglyceridemia. Mutations in the ALMS1 gene have been found to be causative for AS with a total of 79 disease-causing mutations having been described.

Case presentation

We describe the case of a 27-year old female from an English (Caucasian) kindred. She had been initially referred for hypertriglyceridemia, but demonstrated other features suggestive of AS, including blindness, obesity, type 2 diabetes, renal dysfunction, and hypertension. DNA analysis revealed that she is a compound heterozygote with two novel mutations in the ALMS1 gene – H3882Y and V424I. Examination of her family revealed that her phenotypically unaffected mother and younger sister also had heterozygous mutations in the ALMS1 gene. In addition to presenting these novel molecular findings for AS, we review the clinical and genetic features of AS in the context of our case.

Conclusion

Two novel mutations in the ALMS1 gene causative for AS have been reported here, thereby increasing the number of reported mutations to 81 and providing a wider basis for mutational screening among affected individuals.
The Role of the Orbitofrontal Cortex in Anxiety Disorders
Authors: MILAD MOHAMMED R. , RAUCH SCOTT L.
Published: December 2007

Abstract: Advances in neuroimaging techniques over the past two decades have allowed scientists to investigate the neurocircuitry of anxiety disorders. Such research has implicated the orbitofrontal cortex (OFC). Characterizing the role of OFC in anxiety disorders, however, is principally complicated by two factors–differences in underlying pathophysiology across the anxiety disorders and heterogeneity in function across different OFC sub‐territories. Contemporary neurocircuitry models of anxiety disorders have primarily focused on amygdalo‐cortical interactions. The amygdala is implicated in generating fear responses, whereas cortical regions, specifically the medial OFC (mOFC) and the ventromedial prefrontal cortex (vmPFC), are implicated in fear extinction. In contrast to mOFC, anterolateral OFC (lOFC) has been associated with negative affects and obsessions and thus dysfunctional lOFC may underlie different aspects of certain anxiety disorders. Herein, we aim to review the above‐mentioned theories and provide a heuristic model for conceptualizing the respective roles of mOFC and lOFC in the pathophysiology and treatment of anxiety disorders. We will also review the role of the OFC in fear extinction and the implications of this role to the pathophysiology of anxiety disorders.
Difficulty Overcoming Learned Non‐reward during Reversal Learning in Rats with Ibotenic Acid Lesions of Orbital Prefrontal Cortex
Authors: TAIT DAVID SCOTT , BROWN VERITY J.
Published: December 2007

Abstract: Behavioral flexibility is a concept often invoked when describing the function of the prefrontal cortex. However, the psychological substrate of behavioral flexibility is complex. Its key components are allocation of attention, goal‐directedness, planning, working memory, and response selection. Furthermore, there is evidence that different regions of the prefrontal cortex might be implicated in these different components. In rule‐switching tasks, a distinction is made between errors that are perseverative (difficulty switching from a previously rewarded strategy) and errors due to learned‐irrelevance (difficulty switching to a strategy previously uncorrelated with reward). A similar distinction might be made for reversal learning, which involves inhibition of a previously rewarded response and activation of a previously unrewarded response. Damage to the orbital prefrontal cortex (OPFC) results in a deficit in reversal learning. The present study was designed to examine whether one or both of either perseveration or learned non‐reward might account for the deficit. Rats with bilateral ibotenic acid‐induced lesions of the OPFC were not impaired in acquisition of discriminations. They were impaired, relative to controls, only when they had to overcome learned non‐reward. They did not show enhanced perseveration. We conclude that an inability to overcome learned non‐reward significantly contributes to OPFC lesion‐induced deficits in behavioral flexibility.
Neural Correlates of Inflexible Behavior in the Orbitofrontal–Amygdalar Circuit after Cocaine Exposure
Authors: STALNAKER THOMAS A. , ROESCH MATTHEW R. , CALU DONNA J. , BURKE KATHRYN A. , SINGH TEGHPAL , SCHOENBAUM GEOFFREY
Published: December 2007

Abstract: Addiction is characterized by compulsive or inflexible behavior, observed both in the context of drug‐seeking and in contexts unrelated to drugs. One possible contributor to these inflexible behaviors may be drug‐induced dysfunction within circuits that support behavioral flexibility, including the basolateral amygdala (ABL) and the orbitofrontal cortex (OFC). Here we describe data demonstrating that chronic cocaine exposure causes long‐lasting changes in encoding properties in the ABL and the OFC during learning and reversal in an odor‐guided task. In particular, these data suggest that inflexible encoding in ABL neurons may be the proximal cause of cocaine‐induced behavioral inflexibility, and that a loss of outcome‐expectant encoding in OFC neurons could be a more distal contributor to this impairment. A similar mechanism of drug‐induced orbitofrontal–amygdalar dysfunction may cause inflexible behavior when animals and addicts are exposed to drug‐associated cues and contexts.
Synergistic and Regulatory Effects of Orbitofrontal Cortex on Amygdala‐Dependent Appetitive Behavior
Authors: ROBERTS A. C. , REEKIE Y. , BRAESICKE K.
Published: December 2007

Abstract: This paper will review two avenues of our research in marmosets that have focused on the role of the orbitofrontal cortex (OFC) in amygdala‐dependent appetitive behavior. The first demonstrates the important contribution of both the OFC and the amygdala to conditioned reinforcement (CRF). The second reveals the regulatory effects of the OFC on amygdala‐dependent autonomic and behavioral arousal in appetitive conditioning. The process of CRF is one way in which an environmental cue can guide emotional behavior. As a consequence of its previous relationship with reward, a cue can take on affective value and reinforce behavior. Lesion studies in marmosets are described that show that CRF is dependent upon both the amygdala and OFC. The synergistic interactions between these structures that have been shown to underlie other aspects of reward processing are then considered with respect to CRF. The results are contrasted with those that show the importance of the OFC in suppressing positive affective responses elicited by the amygdala in response to a conditioned stimulus (CS). Specifically, it will be shown that the OFC is involved in the rapid suppression of conditioned autonomic arousal upon CS withdrawal and in the co‐ordination of conditioned autonomic and behavioral responses when adapting to changing reward contingencies. It will be argued that, overall, the OFC plays a critical role in the context‐dependent regulation of positive affective responding governed by external cues, in keeping with a role in executive control.
Symptoms of Frontotemporal Dementia Provide Insights into Orbitofrontal Cortex Function and Social Behavior
Authors: VISKONTAS INDRE V. , POSSIN KATHERINE L. , MILLER BRUCE L.
Published: December 2007

Abstract:  Recent investigations into the brain substrates of behavioral changes in frontotemporal dementia (FTD) demonstrate that the orbitofrontal cortex (OFC) plays a crucial role in normal social and emotional behavior. The initial symptoms of FTD reflect the early involvement of OFC as well as the disruption of an associated network involving the insula, striatum, and medial frontal lobes. As predicted by patients with other types of OFC lesions, FTD patients show impairments involving stimulus‐reward reversal learning, response inhibition, and ability to judge the appropriateness of their behavior in the social context. While the natural reward system remains intact in these patients, that is, patients will seek out directly rewarding stimuli, such as food and sex, with progressive OFC dysfunction they lose the ability to process complex stimulus‐reward contingencies. These abnormalities are apparent in their social interactions, which break down early in the disease. Also, deficits in emotion recognition and empathy have been directly linked to OFC atrophy in these patients. In contrast, some patients with early FTD show intact cognitive skills, including memory and executive functioning. Here, we review the behavioral and neuropsychological changes that accompany OFC atrophy in FTD and argue that phylogenetically new neurons found in this region, called von Economo neurons, are selectively vulnerable in FTD.
A Comparison of Reward‐Contingent Neuronal Activity in Monkey Orbitofrontal Cortex and Ventral Striatum
Authors: SIMMONS JANINE M. , RAVEL SABRINA , SHIDARA MUNETAKA , RICHMOND BARRY J.
Published: December 2007

Abstract:  We have investigated how neuronal activity in the orbitofrontal‐ventral striatal circuit is related to reward‐directed behavior by comparing activity in these two regions during a visually guided reward schedule task. When a set of visual cues provides information about reward contingency, that is, about whether or not a trial will be rewarded, significant subpopulations of neurons in both orbitofrontal cortex and ventral striatum encode this information. Orbitofrontal and ventral striatal neurons also differentiate between rewarding and non‐rewarding trial outcomes, whether or not those outcomes were predicted. The size of the neuronal subpopulation encoding reward contingency is twice as large in orbitofrontal cortex (50% of neurons) as in ventral striatum (26%). Reward‐contingency‐dependent activity also appears earlier during a trial in orbitofrontal cortex than in ventral striatum. The peak reward‐contingency representation in orbitofrontal cortex (31% of neurons), occurs during the wait period, a period of high anticipation prior to any action. The peak ventral striatal representation of reward contingency (18%) occurs during the go period, a time of action. We speculate that signals from orbitofrontal cortex bias ventral striatal activity, and that a flow of reward‐contingency information from orbitofrontal cortex to ventral striatum serves to guide actions toward rewards.
Orbitofrontal Cortex Function and Structure in Depression
Authors: DREVETS WAYNE C.
Published: December 2007

Abstract:  The orbitofrontal cortex (OFC) has been implicated in the pathophysiology of major depression by evidence obtained using neuroimaging, neuropathologic, and lesion analysis techniques. The abnormalities revealed by these techniques show a regional specificity, and suggest that some OFC regions which appear cytoarchitectonically distinct also are functionally distinct with respect to mood regulation. For example, the severity of depression correlates inversely with physiological activity in parts of the posterior lateral and medial OFC, consistent with evidence that dysfunction of the OFC associated with cerebrovascular lesions increases the vulnerability for developing the major depressive syndrome. The posterior lateral and medial OFC function may also be impaired in individuals who develop primary mood disorders, as these patients show grey‐matter volumetric reductions, histopathologic abnormalities, and altered hemodynamic responses to emotionally valenced stimuli, probabilistic reversal learning, and reward processing. In contrast, physiological activity in the anteromedial OFC situated in the ventromedial frontal polar cortex increases during the depressed versus the remitted phases of major depressive disorder to an extent that is positively correlated with the severity of depression. Effective antidepressant treatment is associated with a reduction in activity in this region. Taken together these data are compatible with evidence from studies in experimental animals indicating that some orbitofrontal and medial prefrontal cortex regions function to inhibit, while others function to enhance, emotional expression. Alterations in the functional balance between these regions and the circuits they form with anatomically related areas of the temporal lobe, striatum, thalamus, and brain stem thus may underlie the pathophysiology of mood disorders, such as major depression.
Flexible Neural Representations of Value in the Primate Brain
Authors: SALZMAN C. DANIEL , PATON JOSEPH J. , BELOVA MARINA A. , MORRISON SARA E.
Published: December 2007

Abstract: The amygdala and orbitofrontal cortex (OFC) are often thought of as components of a neural circuit that assigns affective significance—or value—to sensory stimuli so as to anticipate future events and adjust behavioral and physiological responses. Much recent work has been aimed at understanding the distinct contributions of the amygdala and OFC to these processes, but a detailed understanding of the physiological mechanisms underlying learning about value remains lacking. To gain insight into these processes, we have focused initially on characterizing the neural signals of the primate amygdala, and more recently of the primate OFC, during appetitive and aversive reinforcement learning procedures. We have employed a classical conditioning procedure whereby monkeys form associations between visual stimuli and rewards or aversive stimuli. After learning these initial associations, we reverse the stimulus‐reinforcement contingencies, and monkeys learn these new associations. We have discovered that separate populations of neurons in the amygdala represent the positive and negative value of conditioned visual stimuli. This representation of value updates rapidly upon image value reversal, as fast as monkeys learn, often within a single trial. We suggest that representations of value in the amygdala may change through multiple interrelated mechanisms: some that arise from fairly simple Hebbian processes, and others that may involve gated inputs from other brain areas, such as the OFC.
The Orbitofrontal Cortex: Novelty, Deviation from Expectation, and Memory
Authors: PETRIDES MICHAEL
Published: December 2007

Abstract:  The orbitofrontal cortex is strongly connected with limbic areas of the medial temporal lobe that are critically involved in the establishment of declarative memories (entorhinal and perirhinal cortex and the hippocampal region) as well as the amygdala and the hypothalamus that are involved in emotional and motivational states. The present article reviews evidence regarding the role of the orbitofrontal cortex in the processing of novel information, breaches of expectation, and memory. Functional neuroimaging evidence is provided that there is a difference between the anterior and posterior orbitofrontal cortex in such processing. Exposure to novel information gives rise to a selective increase of activity in the granular anterior part of the orbitofrontal cortex (area 11) and this activity increases when subjects attempt to encode this information in memory. If the stimuli violate expectations (e.g., inspection of graffiti‐like stimuli in the context of other regular stimuli) or are unpleasant (i.e., exposure to the sounds of car crashes), there is increased response in the posteromedial agranular/dysgranular area 13 of the orbitofrontal region. The anatomic data provide a framework within which to understand these functional neuroimaging findings.
Discovery of a Functional Glucocorticoid Receptor β-Isoform in Zebrafish
Authors: Schaaf Marcel J. M. , Champagne Danielle , van Laanen Ivo H. C. , van Wijk Diane C. W. A. , Meijer Annemarie H. , Meijer Onno C. , Spaink Herman P. , Richardson Michael K.
Published: December 2007

In humans, two glucocorticoid receptor (GR) splice variants exist: GRα and GRβ, which are identical between amino acids 1–727 and then diverge. Whereas GRα (the canonical GR) acts as a ligand-activated transcription factor, GRβ does not bind traditional glucocorticoid agonists, lacks GRα’s transactivational activity, and acts as a dominant-negative inhibitor of GRα. It has been suggested that this receptor isoform is involved in the induction of glucocorticoid resistance in asthma patients. Unfortunately, a GR β-isoform has been detected in only humans, and therefore, an animal model for studies on this isoform is lacking. In the present study, we demonstrate that in zebrafish a GR isoform exists that diverges from the canonical zebrafish GR at the same position as human GRβ from human GRα. The zebrafish GR β-isoform acts as a dominant-negative inhibitor in reporter assays, and the extent of inhibition and the effective GRα/GRβ ratio is similar to studies performed with the human GR isoforms. In addition, the subcellular localization of zebrafish GRβ is similar to its human equivalent. Finally, expression levels of GRα and GRβ were determined in adult zebrafish tissues and at several developmental stages. Both receptor isoforms were detected throughout the body, and GRβ mRNA levels were relatively low compared with GRα mRNA levels, as in humans. Thus, for the first time, a GR β-isoform has been identified in a nonhuman animal species, shedding new light on the relevance of this GR splice variant and providing a versatile animal model for studies on the GR system.
A study of in-process waiting time on a linear walking worker assembly line
Authors: Lassalle S , Wang Q , Owen G W , Mileham A R
Published: December 2007

This paper presents a study of in-process waiting times on a linear walking worker assembly line in a real buffer-constrained flowshop environment using the simulation method. The in-process waiting time can lead to production loss and in-process inventory; it can also affect the throughput time for completion of a product assembled in a sequential flowline-based manufacturing system. The aim of this research is to investigate the varying magnitude of the total in-process waiting time for individual walking workers who may have to wait to carry out operations at a station due to blocking on the line ahead. The results were obtained by varying a number of system parameters embedded in a simulation model created using Witness® with the key input/output data being manipulated by a series of MS Excel-spreadsheets. The main finding of this work is that the in-process waiting time (which affects the expected throughput time) can be determined and it is adjustable by the strategic application of walking workers on a linear assembly line, even if the system behaviour is random.
Improving surface integrity and economics of grinding by optimum coolant application, with consideration of abrasive tool and process regime
Authors: Webster J A
Published: December 2007

As compared to machining, the chip thickness in grinding is small and the specific grinding energy is generally much higher than the specific cutting energy in machining. With such small chip thickness values, a lot of heat is created by non-chip removal interactions, such as ploughing and rubbing. These interactions occur between the chip and grain, chip and bond, and the chip and the work. Identification and manipulation of these interactions can allow the engineer to minimize the thermal limitation, improve surface finish, increase wheel life, etc.

This paper discusses the thermal energy partitioning that occurs with different modes of grinding, and guides the reader towards processes with a lower specific energy and more desirable energy partitioning with respect to the energy that enters the final workpiece surface. The high efficiency deep grinding regime, is compared to creep-feed and shallow-cut grinding.

The paper also looks at the cooling effect of grinding fluids and how they can be applied more effectively to cool and lubricate the workpiece surface. Best practices will be presented, based on analytical models and field experience. Flowrate and pressure models are used to optimize the main fluid jet that is applied to the grinding process. The heat transfer characteristics of superabrasive wheels, as compared to conventional abrasives, will also be presented and discussed.

Finally, a case study is presented, that clearly shows the economic and technological advantages of coherent-jet nozzles over a more conventional approach.
An investigation into the ball burnishing of aluminium alloy 6061-T6
Authors: El-Axir M H
Published: December 2007

Burnishing has been widely used to produce excellent surface finish, work hardening, and compressive residual stress by plastically deforming the workpiece surface. There have been very few studies concerning the effect of burnishing parameters on the fatigue life. The purpose of this work is to study the relationships between the fatigue life, the residual stress, and the ball burnishing process parameters. Experimental work was carried out on a lathe to establish the effect of three burnishing parameters, namely the burnishing speed, burnishing force, and burnishing feed, on the residual stress and fatigue life of aluminium alloy 6061-T6. The residual stress distribution in the surface region due to ball burnishing is determined using a deflectionetching technique. The number of cycles to failure is determined for each specimen using a universal-type fatigue machine, which is suitable for testing specimens requiring oscillatory or reciprocating motion.

It was found that all input parameters have controlling effects, to different extents, on the residual stress and fatigue life. The results showed that the residual stress plays an important role in controlling the behaviour of fatigue. The burnishing force and burnishing feed are the most important parameters controlling the values of the compressive residual stress which, in turn, delay crack initiation, resulting in an increase in the fatigue life.
Prediction of burr formation during face milling using an artificial neural network with optimized cutting conditions
Authors: Lee S H , Dornfeld D A
Published: December 2007

Burrs formed during face milling operations are difficult to characterize because there are several parameters with complex interactions that affect the cutting process. In this paper, a combined artificial intelligence and optimization approach is introduced to predict burr types formed during face milling. The Taguchi method was selected for the optimization and an artificial neural network (ANN) was constructed for the machining of aluminium alloy 6061-T6. For the training of the ANN, the input was non-dimensionalized using the optimized results from the Taguchi method. The resulting ANN output was in agreement with experimental results, validating the proposed scheme.
Data mining: A tool for detecting cyclical disturbances in supply networks
Authors: Afify A A , Dimov S S , Naim M , Valeva V , Shukla V
Published: December 2007

Disturbances in supply chains may be either exogenous or endogenous. The ability automatically to detect, diagnose, and distinguish between the causes of disturbances is of prime importance to decision makers in order to avoid uncertainty. The spectral principal component analysis (SPCA) technique has been utilized to distinguish between real and rogue disturbances in a steel supply network. The data set used was collected from four different business units in the network and consists of 43 variables; each is described by 72 data points. The present paper will utilize the same data set to test an alternative approach to SPCA in detecting the disturbances. The new approach employs statistical data pre-processing, clustering, and classification learning techniques to analyse the supply network data. In particular, the incremental k-means clustering and the RULES-6 classification rule-learning algorithms, developed by the present authors' team, have been applied to identify important patterns in the data set. Results show that the proposed approach has the capability automatically to detect and characterize network-wide cyclical disturbances and generate hypotheses about their root cause.
Development of a three-dimensional contouring measuring system and error compensation method for a CNC machine tool
Authors: Jywe W Y , Chou C T , Chen C J , Yang T Y , Jwo H H
Published: December 2007

The traditional method of dynamic performance inspection for a machine tool is to use a double ball bar (DBB) and grid encoder for contouring tests. With the increasing demand for miniaturization and fast machining in industry. DBB has an inadequate dynamic performance for inspection in conditions that have a small working range, high speed, 3D measurement, and so on. The present paper describes the development of a high-speed dynamic performance measurement system with position-sensitive detectors (PSDs). It consists of two PSDs and two laser diodes. After calibration and actual measurement, the system was verified to be competent for measuring the static and dynamic error of the linear axis in one, two, or three dimensions with a system resolution of 0.5 μm and a repeatability of 1 μm. The current paper focuses on measuring the machine tool controller performance in three-dimensional (3D) high-speed motion. When the machine tool moves with high-speed, machining errors can easily occur on the workpiece; 3D error compensation methods are put forward in this paper to solve this problem. The methods were verified as significantly decreasing the contouring error.
Handbuch der historischen Buchbestände. Hg. von Bernhard Fabian. 1996–2001
Authors: Harms Wolfgang
Published: December 2007

Wie schon in der Besprechung der ersten erschienenen Bände angekündigt (vgl. Arbitrium 15 [1997], S. 139–143), sind die weiteren Bände dieses Handbuchs zügig erschienen: Die erste Reihe, die den historischen Buchbeständen (bis 1900) in Deutschland gewidmet ist, liegt in 22 nach Bundesländern geordneten Bänden sowie in fünf Registerbänden abgeschlossen vor, ebenfalls die zweite Reihe, deren vier Bände die Altbestände Österreichs erschließen. Von der dritten Reihe, die den deutschsprachigen und den anderen im deutschen Sprachgebiet gedruckten historischen Beständen im übrigen Europa gewidmet ist, sind jetzt auch bereits sämtliche Bände (bis auf die Register) greifbar. Die gesamte Anlage des Handbuchs bewährt sich von Band zu Band weiterhin. Die Darstellung der Geschichte der einzelnen Bibliothek zeigt, in welcher Weise einzelne Sammlerpersönlichkeiten, wie die Aufgabenstellungen institutioneller Art (Universität, Schule, Kommune, Verein) und wie Schenkungen am Zusammenwachsen des Bestands beteiligt sind. Von dorther erhalten die sorgfältigen Angaben zu besonderen Schwerpunkten im heutigen Bestand ihren historischen Hintergrund. Der hohe Anteil an Privatbibliotheksbeständen innerhalb der großen Staats-, Landes-, Universitäts- und Stadtbibliotheken zeigt erneut die Bedeutung individuell ausgeprägter Sammlerintentionen für die übergeordnete Leistung der Bibliotheken, das kulturelle Bewußtsein erreichbar und stets wahrnehmbar zu machen.
Münchner Altbestandskatalog. Bayerische Staatsbibliothek 1501–1850. Universitätsbibliothek München 1501–1850. 2. CD-ROM-Edition. 2001
Authors: Peil Dietmar
Published: December 2007

Nachdem 1996 bereits der Altbestand der Bayerischen Staatsbibliothek erstmals auf einer CD-ROM erfaßt war, die durchaus positive Resonanz fand, ist am 1. Februar 2001 die erweiterte Neuausgabe dieses nützlichen Hilfsmittels zur bibliographischen Recherche im Historicum der Universität München der staunenden Öffentlichkeit vorgestellt worden. Außer den etwa 570 000 Titeln der Staatsbibliothek – in der Erstausgabe fanden sich ‚nur‘ etwa 550 000 Titel – ist nun auch der Altbestand der Universitätsbibliothek mit etwa 300 000 Einträgen verzeichnet. Der Zugriff auf die Datenfülle ist über verschiedene Modi möglich. Im Standardmodus, der nach dem Start des Programms als erstes angeboten wird, sind die Suchkategorien (wie zum Beispiel Verfasser, Titel, Erscheinungsort, -jahr) explizit zu benennen und können in den unterschiedlichsten Variationen kombiniert werden.
Andreas B. Kilcher (Hg.), Metzler Lexikon der deutsch-jüdischen Literatur. 2000
Authors: Mosès Stéphane
Published: December 2007

Das von Andreas Kilcher herausgegebene Lexikon der deutsch-jüdischen Literatur ist das erste zugleich ausführliche und übersichtliche Nachschlagewerk in diesem of besprochenen, aber bis jetzt noch weit unbekannten Gebiet der deutschen Literatur. Von dem vierbändigen, von Renate Heuer im Rahmen der Bibliographia Judaica veröffentlichten Verzeichnis jüdischer Autoren deutscher Sprache (1982–1995), sowie von dem von derselben geleiteten Lexikon deutsch-jüdischer Autoren (1992ff.) unterscheidet sich das von Kilcher herausgegebene Lexikon zuerst dadurch, daß es erst mit der Aufklärung beginnt, dagegen allerdings bis zur jüngsten Gegenwart führt, aber hauptsächlich dadurch, daß es sich hier nicht um ein einfaches Verzeichnis handelt, sondern um eine Reihe von 270 Porträts, die von etwa hundert verschiedenen Wissenschaftler(inne)n aus Deutschland, Österreich, der Schweiz, England, Israel und den USA verfaßt worden sind. In seiner ausgezeichneten methodologischen Einleitung macht Kilcher klar, daß diese fragmentierte Darstellungsweise die überzeugendste Art und Weise ist, dem Wesen eines Gebiets gerecht zu werden, das sich jeglichem totalisierenden Definitionsversuch entzieht. Denn gerade an der Suche nach einer eindeutigen Festlegung des Begriffs einer deutsch-jüdischen Literatur sind alle bisher in dieser Richtung unternommenen Vorhaben gescheitert. Keines der beiden Kriterien, an denen die Zugehörigkeit eines deutschschreibenden Autors zum Felde der deutsch-jüdischen Literatur gemessen werden könnte, und zwar entweder seine Herkunft oder die von ihm behandelte Thematik, ist an und für sich eindeutig genug, um eine solche Definition zu erlauben.