bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of radiation pressure on dusty absorbing gas around active galactic nuclei
Authors: Fabian A. C. , Vasudevan R. V. , Gandhi P. 
Published: February 2008

Abstract
Many active galactic nuclei (AGN) are surrounded by gas which absorbs the radiation produced by accretion on to the central black hole and obscures the nucleus from direct view. The dust component of the gas greatly enhances the effect of radiation pressure above that for Thomson scattering so that an AGN which is sub-Eddington for ionized gas in the usual sense can appear super-Eddington for cold dusty gas. The radiation pressure enhancement factor depends on the AGN spectrum but ranges between unity and about 500, depending on the column density. It means that an AGN for which the absorption is long-lived should have a column density of NH &gt; 5 × 1023λ cm−2, where λ is its Eddington fraction Lbol/LEdd, provided that NH &gt; 5 × 1021 cm−2. We have compared the distribution of several samples of AGN – local, Chandra Deep Field-South and Lockman Hole – with this expectation and find good agreement. We show that the limiting enhancement factor can explain the black hole mass–bulge mass relation and note that the effect of radiation pressure on dusty gas may be a key component in the feedback of momentum and energy from a central black hole to a galaxy.
Does a detection team shorten duration of untreated psychosis?
Authors: Nordentoft Merete , Thorup Anne , Petersen Lone , Øhlenschlæger Johan , Christensen Torben Østergaard , Krarup Gertrud , Jørgensen Per , Jeppesen Pia 
Published: February 2008

AbstractIntroduction: Duration of untreated psychosis (DUP) is shown to be associated with poor outcome in many domains. It has been shown that it is possible to shorten DUP when combining a detection team and an information campaign. The aim of this study was to evaluate whether DUP was shortened during the first 3 years after establishing detection teams without a concomitant information campaign.Methods: All patients included in the OPUS trial were examined with the Instrument for Retrospective Assessment of Onset of Psychosis to determine DUP. A total of 552 patients with first episode psychotic disorder (n = 470) or schizotypal disorder (n = 82) were included in the study. The 3‐year inclusion period was divided into six consecutive periods of 6 months each.Results: The median DUP was 52 weeks. DUP was not significantly reduced during the 3‐year inclusion period, but a larger proportion of patients with symptoms below the threshold for frank psychosis were included compared with the beginning of the trial. The proportion referred from primary care remained small (8–10%) and unchanged during the inclusion period.Discussion: The availability of a detection team increased the referral of patients with schizotypal disorder, but the DUP among psychotic patients remained almost unaltered throughout the period. It seems that an information campaign and possibilities for direct access and self‐referral are necessary in order to shorten DUP.
Preliminary neuropsychological findings in individuals at high genetic risk for schizophrenia
Authors: Bertisch Hilary C. , Fava Joanna , Kattan Ayelet , DeLisi Lynn E. 
Published: February 2008

AbstractAims: An understanding of baseline cognitive function in individuals at high genetic risk for schizophrenia could provide important information about the neurodevelopmental course of the illness and assist with early detection. In an effort to identify potential markers for the illness, this study investigates domains of neuropsychological functioning in a sample of young individuals at risk for developing schizophrenia.Methods: Twenty‐two individuals with schizophrenia, 16 participants at high risk and 31 controls participated in comprehensive cognitive assessments.Results: Results support reports of a trend for high‐risk participants to score intermediate to the other groups on a general cognitive battery, as well as evidencing deficits in specific skills like visual memory. The pattern appears to exist independently of and prior to the onset of prodromal symptoms.Conclusions: These findings support the hypothesis that a common cognitive pattern exists across individuals with genetic risk that may later develop into a clear psychotic illness. Further longitudinal investigation with larger cohorts is crucial to understanding these findings.
Mechanisms of Varicella-Zoster Virus Neuropathogenesis in Human Dorsal Root Ganglia
Authors: Reichelt Mike , Zerboni Leigh , Arvin Ann M. 
Published: February 2008

ABSTRACT
Varicella-zoster virus (VZV) is a human alphaherpesvirus that infects sensory ganglia and reactivates from latency to cause herpes zoster. VZV replication was examined in human dorsal root ganglion (DRG) xenografts in mice with severe combined immunodeficiency using multiscale correlative immunofluorescence and electron microscopy. These experiments showed the presence of VZV genomic DNA, viral proteins, and virion production in both neurons and satellite cells within DRG. Furthermore, the multiscale analysis of VZV-host cell interactions revealed virus-induced cell-cell fusion and polykaryon formation between neurons and satellite cells during VZV replication in DRG in vivo. Satellite cell infection and polykaryon formation in neuron-satellite cell complexes provide mechanisms to amplify VZV entry into neuronal cell bodies, which is necessary for VZV transfer to skin in the affected dermatome during herpes zoster. These mechanisms of VZV neuropathogenesis help to account for the often severe neurologic consequences of herpes zoster.
Development of an improved Pseudoalteromonas haloplanktis TAC125 strain for recombinant protein secretion at low temperature
Authors: Parrilli Ermenegilda , De Vizio Daniela , Cirulli Claudia , Tutino Maria Luisa 
Published: February 2008

Abstract

Background
In a previous paper, we reported the accomplishment of a cold gene-expression system for the recombinant secretion of heterologous proteins in Pseudoalteromonas haloplanktis TAC125. This system makes use of the psychrophilic α-amylase from P. haloplanktis TAB23 as secretion carrier, and allows an effective extra-cellular addressing of recombinant proteins. However, Pseudoalteromonales are reported to secrete a wide range of extra-cellular proteases. This feature works against the efficiency of the cold-adapted secretion system, because of the proteolytic degradation of recombinant products. The aim of this study is the construction of a P. haloplanktis TAC125 mutant strain with reduced extra-cellular proteolytic activity.

Results

P. haloplanktis TAC125 culture medium resulted to contain multiple and heterogeneous proteases. Since the annotation of the Antarctic bacterium genome highlighted the presence of only one canonical secretion machinery, namely the Type II secretion pathway (T2SS), we have inactivated this secretion system by a gene insertion strategy. A mutant strain of P. haloplanktis TAC125 in which the gspE gene was knocked-out, actually displayed a remarkable reduction of the extra-cellular protease secretion. Quite interestingly this strain still retained the ability to secrete the psychrophilic amylase as efficiently as the wild type. Moreover, the decrease in extra-cellular proteolytic activity resulted in a substantial improvement in the stability of the secreted amylase-β-lactamase chimera.

Conclusion
Here we report a cell engineering approach to the construction of a P. haloplanktis TAC125 strain with reduced extra-cellular protease activity. The improved strain is able to secrete the psychrophilic α-amylase (the carrier of our recombinant secretion system), while it displays a significant reduction of protease content in the culture medium. These features make the gspE mutant an improved host with a remarkable biotechnological potential in recombinant protein secretion at low temperature. Moreover this work demonstrates that P. haloplanktis TAC125 is a versatile psychrophilic host for recombinant protein production since it can be easily improved by a directed engineering approach. To the best of our knowledge, this is the first described example of a strain improvement strategy applied to an Antarctic bacterium.
Ambient Intelligence: Basic Elements and Insights (Ambient Intelligence: Grundelemente und Einsichten)
Authors: Aarts Emile 
Published: February 2008

Summary
Ambient Intelligence (AmI) is about smart everyday technology that makes sense. The concept refers to electronic environments that are sensitive and responsive to the presence of people. The paradigm relates to a vision on digital systems for the years 2010–2020 which was developed in the late nineties of the past century, and which has become quite influential worldwide in the development of new concepts for information processing. The novel and disruptive element of the vision is that it combines in a unique way elements from multi-disciplinary fields such as electrical engineering, computer science, industrial design, user interfaces, and cognitive sciences into highly integrated systems by a user-centered design approach.
Zellulare Transportsysteme – Den Dingen Beine machen im „Internet der Dinge” (Cellular Transport Systems – Making Things Move in the “Internet of Things”)
Authors: ten Hompel Michael , Nagel Lars 
Published: February 2008

Zusammenfassung
Hochautomatisierte intralogistische Systeme sind ein in der Anwendung befindliches Domänenbeispiel intelligenter Umgebungen. Ausgehend vom Status Quo in der Kommissionierung über den Einsatz von Agenten- und RFID-Technologien, die Multiagentensimulation und die Entwicklung von intelligenten Behältern wird konsequent der Weg hin zur vollkommen autonomen Gestaltung des Materialflusses im Konzept der zellularen Transportsysteme aufgezeigt.
Global Breakdancing and the Intercultural Body
Authors: Osumare Halifu 
Published: February 2008

When I arrived at nine o'clock, the deejay was spinning “trip hop” style disks in the “chill room” upstairs until the formal dance show was supposed to start at ten o'clock downstairs. Critical mass is important: the event did not begin until midnight; size of crowd and group energy are the determining factors for starting time in hip hop culture. Eventually, the audience of about two hundred consisted of black, white, Asian, Hawaiian, military, and civilian patrons who were mostly in their late twenties. “What's up, y'all? Y'all ready for the show?” asked Jamal, Honolulu hip hop promoter and emcee, to open the event.Jamal proceeded to read from a script about the beginnings of American society's acceptance of “African American culture in the 1920s Jazz Age,” putting what was about to happen in historical context and giving the event an informative purpose. This scripted narration of hip hop's historical context at a club event reflected an interest in specific African American origins of the pop culture form expressed by many global hip hop leaders. Thus began “Urban Movement,” a November 1998 b-boy (breakdance) event produced at the Wave Waikiki nightclub in Honolulu, on the island of Oahu. What followed was a demonstration of the current-day variations of hip hop dance that began in the 1970s with virtuosic athletic b-boying or b-girling and “popping,” the phenomenal muscular control of the rapid-fire rhythmic isolations. Urban Movement provided several hip hop enactments that illuminated what I investigate in this essay—the interdependence of performance and performativity as dual forces in global breakdancing.
Self‐modelling regression for longitudinal data with time‐invariant covariates
Authors: Altman Naomi , Villarreal Julio 
Published: February 2008

AbstractThe authors propose the use of self‐modelling regression to analyze longitudinal data with time invariant covariates. They model the population time curve with a penalized regression spline and use a linear mixed model for transformation of the time and response scales to fit the individual curves. Fitting is done by an iterative algorithm using off‐the‐shelf linear and nonlinear mixed model software. Their method is demonstrated in a simulation study and in the analysis of tree swallow nestling growth from an experiment that includes an experimentally controlled treatment, an observational covariate and multi‐level sampling.
Optimal sampling for repeated binary measurements
Authors: Quintana Fernando A. , Müller Peter 
Published: February 2008

AbstractThe authors consider the optimal design of sampling schedules for binary sequence data. They propose an approach which allows a variety of goals to be reflected in the utility function by including deterministic sampling cost, a term related to prediction, and if relevant, a term related to learning about a treatment effect To this end, they use a nonparametric probability model relying on a minimal number of assumptions. They show how their assumption of partial exchangeability for the binary sequence of data allows the sampling distribution to be written as a mixture of homogeneous Markov chains of order k. The implementation follows the approach of Quintana & Müller (2004), which uses a Dirichlet process prior for the mixture.
Preclassic Obsidian Procurement and Utilization at the Maya Site of Colha, Belize
Authors: Brown David O. , Dreiss Meredith L. , Hughes Richard E. 
Published: February 2008

Abstract This study explores the early use of obsidian at the Maya site of Colha in northern Belize and the implications that variations in source distribution have for the site and its regional connections. Energy dispersive x-ray fluorescence (EDXRF) analysis of 104 specimens of obsidian from Preclassic contexts at the site identified El Chayal obsidian as the most common overall followed closely by that from San Martin Jilotepeque. Ixtepeque obsidian, not common in many Preclassic assemblages, was also strongly represented. The results revealed a Middle Preclassic dependence on San Martin obsidian gradually diminishing through the Preclassic to the Classic period, when San Martin all but disappears from the site. A corresponding increase in El Chayal obsidian use through time at Colha coincides with the rise of Kaminaljuyu in the Guatemalan highlands. Analysis of the obsidian by context indicated that El Chayal obsidian dominated in architectural and ritual deposits while Ixtepeque obsidian was the most common in workshops. San Martin accounted for a slightly greater percentage than El Chayal obsidian in middens, with Ixtepeque materials notably less common. The data indicate that Colha was connected to a broad distribution network from the Middle Preclassic onward, and that obsidian source variability was greater during the Preclassic than the subsequent Classic period.
Kernel‐based learning for biomedical relation extraction
Authors: Li Jiexun , Zhang Zhu , Li Xin , Chen Hsinchun 
Published: February 2008

AbstractRelation extraction is the process of scanning text for relationships between named entities. Recently, significant studies have focused on automatically extracting relations from biomedical corpora. Most existing biomedical relation extractors require manual creation of biomedi‐cal lexicons or parsing templates based on domain knowledge. In this study, we propose to use kernel‐based learning methods to automatically extract biomedical relations from literature text. We develop a framework of kernel‐based learning for biomedical relation extraction. In particular, we modified the standard tree kernel function by incorporating a trace kernel to capture richer contextual information. In our experiments on a biomedi‐cal corpus, we compare different kernel functions for biomedical relation detection and classification. Theexperimental results show that a tree kernel outperforms word and sequence kernels for relation detection, our trace‐tree kernel outperforms the standard tree kernel, and a composite kernel outperforms individual kernels for relation extraction.
A stochastic model for predicting dextrose equivalent and saccharide composition during hydrolysis of starch by α‐amylase
Authors: Besselink Tamara , Baks Tim , Janssen Anja E.M. , Boom Remko M. 
Published: February 2008

AbstractA stochastic model was developed that was used to describe the formation and breakdown of all saccharides involved during α‐amylolytic starch hydrolysis in time. This model is based on the subsite maps found in literature for Bacillus amyloliquefaciens α‐amylase (BAA) and Bacillus licheniformis α‐amylase (BLA). Carbohydrate substrates were modeled in a relatively simple two‐dimensional matrix. The predicted weight fractions of carbohydrates ranging from glucose to heptasaccharides and the predicted dextrose equivalent showed the same trend and order of magnitude as the corresponding experimental values. However, the absolute values were not the same. In case a well‐defined substrate such as maltohexaose was used, comparable differences between the experimental and simulated data were observed indicating that the substrate model for starch does not cause these deviations. After changing the subsite map of BLA and the ratio between the time required for a productive and a non‐productive attack for BAA, a better agreement between the model data and the experimental data was observed. Although the model input should be improved for more accurate predictions, the model can already be used to gain knowledge about the concentrations of all carbohydrates during hydrolysis with an α‐amylase. In addition, this model also seems to be applicable to other depolymerase‐based systems. Biotechnol. Bioeng. 2008;100: 684–697. © 2008 Wiley Periodicals, Inc.
High‐throughput microplate technique for enzymatic hydrolysis of lignocellulosic biomass
Authors: Chundawat Shishir P.S. , Balan Venkatesh , Dale Bruce E. 
Published: February 2008

AbstractSeveral factors will influence the viability of a biochemical platform for manufacturing lignocellulosic based fuels and chemicals, for example, genetically engineering energy crops, reducing pre‐treatment severity, and minimizing enzyme loading. Past research on biomass conversion has focused largely on acid based pre‐treatment technologies that fractionate lignin and hemicellulose from cellulose. However, for alkaline based (e.g., AFEX) and other lower severity pre‐treatments it becomes critical to co‐hydrolyze cellulose and hemicellulose using an optimized enzyme cocktail. Lignocellulosics are appropriate substrates to assess hydrolytic activity of enzyme mixtures compared to conventional unrealistic substrates (e.g., filter paper, chromogenic, and fluorigenic compounds) for studying synergistic hydrolysis. However, there are few, if any, high‐throughput lignocellulosic digestibility analytical platforms for optimizing biomass conversion. The 96‐well Biomass Conversion Research Lab (BCRL) microplate method is a high‐throughput assay to study digestibility of lignocellulosic biomass as a function of biomass composition, pre‐treatment severity, and enzyme composition. The most suitable method for delivering milled biomass to the microplate was through multi‐pipetting slurry suspensions. A rapid bio‐enzymatic, spectrophotometric assay was used to determine fermentable sugars. The entire procedure was automated using a robotic pipetting workstation. Several parameters that affect hydrolysis in the microplate were studied and optimized (i.e., particle size reduction, slurry solids concentration, glucan loading, mass transfer issues, and time period for hydrolysis). The microplate method was optimized for crystalline cellulose (Avicel) and ammonia fiber expansion (AFEX) pre‐treated corn stover. Biotechnol. Bioeng. 2008;99: 1281–1294. © 2008 Wiley Periodicals, Inc.
Co‐immobilization of dextransucrase and dextranase for the facilitated synthesis of isomalto‐oligosaccharides: Preparation, characterization and modeling
Authors: Erhardt Frank A. , Kügler Jonas , Chakravarthula Raghavender R. , Jördening Hans‐Joachim 
Published: February 2008

AbstractCo‐Immobilization of dextransucrase (DS) and dextranase (DN) into calcium alginate includes the co‐entrapment of soluble DS and adsorbed DN. DS converts sucrose into dextran, which is the substrate for DN, so that isomalto‐oligosaccharides (IMOs) are follow‐up products of dextran hydrolysis. The boundary conditions for the successful preparation are investigated with respect to choice of DN adsorbate, surface modifications using blotting agents and optimal enzyme activity ratios. Further, repetitive batch experiments suggest the selection of medium activity ratios for continuous use (0.3 UDNU−1DS, e.g.). Product formation at various cosubstrate:substrate concentrations as well as at different DN:DS ratios are discussed. Moreover, the complexity of the bi‐enzymatic system can be reduced considering the molar ratios of cosubstrate:substrate (glucose:sucrose). Based on these factors, a mechanistic kinetic model is developed, which distinguishes the corresponding contributions of the two enzymes upon overall product formation. In general, at low glucose:sucrose ratios isomaltose synthesis is featured primarily by DN action. Yet with increasing amounts of glucose both the quantity and quality of DN substrate changes, so that its contribution to product formation decreases in an exponential manner; still the overall product yield continuously increases due to enhanced DS contribution. Biotechnol. Bioeng. 2008;100: 673–683. © 2008 Wiley Periodicals, Inc.
Bacterial chemotaxis transverse to axial flow in a microfluidic channel
Authors: Lanning Larry M. , Ford Roseanne M. , Long Tao 
Published: February 2008

AbstractSwimming bacteria sense and respond to chemical signals in their environment. Chemotaxis is the directed migration of a bacterial population toward increasing concentrations of a chemical that they perceive to be beneficial to their survival. Bacteria that are indigenous to groundwater environments exhibit chemotaxis toward chemical contaminants such as hydrocarbons, which they are also able to degrade. This phenomenon may facilitate bioremediation processes by bringing bacteria into closer proximity to these contaminants. A microfluidic device was assembled to study chemotaxis transverse to advective flow. Using a T‐shaped channel design (T‐sensor), two fluid streams were brought into contact by impinging flow. They then flowed adjacent to each other along a transparent channel. An advantage to this design is that it allows real‐time visualization of bacterial distributions within the channel. Under laminar flow conditions a chemotactic driving force was created perpendicular to the direction of flow by diffusion of the chemical attractant from one input stream to the other. A comparison of the chemotactic band behavior in the absence and presence of flow showed that fluid velocity did not significantly impede chemotactic migration in the transverse direction. Biotechnol. Bioeng. 2008;100: 653–663. © 2008 Wiley Periodicals, Inc.