bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracellular proteasome in the human alveolar space: a new housekeeping enzyme?
Authors: Sixt Stephan Urs , Beiderlinden Martin , Jennissen Herbert Peter , Peters Jürgen
Published: January 2007

We hypothesized that 20S proteasome is present and functional in the extracellular alveolar space in humans. Proteasomal activity was measured in bronchoalveolar lavage (BAL) supernatant from eight humans using specific proteasomal fluorogenic substrates and I125-albumin with and without specific proteasome inhibitors. Furthermore, gelfiltration, Western blot technique, and mass spectrometry were applied for proteasome characterization. All proteasomal fluorogenic substrates were hydrolyzed by BAL supernatant, with hydrolysis inhibited by epoxomicin ( P = 0.024) and other proteasome inhibitors as well. E64, a lysosomal inhibitor, did not inhibit enzyme activity. The majority of proteolytic activity was detected in BAL supernatant rather than in the cell pellet. No correlation was found between proteasomal hydrolysis in BAL supernatant and lactate dehydrogenase activity, the total cell count in the cell pellet, and the fraction of avital cells in the cell pellet, ruling out cell lysis as a major source of proteasomal activity. Gelfiltration revealed hydrolyzing activity in the supernatant at 660 kDa and proteasome core proteins after analysis by ESI-QqTOF mass spectrometry. Furthermore, Western blots using a polyclonal antibody against proteasomal α-/β-subunits detected proteasomal proteins in the typical 20- to 30-kDa range in BAL supernatant. Incubation of BAL supernatant with I125-albumin showed a high mean cleavage rate (101.8 μg/ml × h lavage ± 46 SD) that was inhibited by epoxomicin ( P = 0.013) and was ATP and ubiquitin independent. We identified for the first time extracellular, biologically active, ATP- and ubiquitin-independent 20S proteasome in the human alveolar space, with a high albumin cleavage rate. Possibly, the proteasome assists in maintenance of a low intra-alveolar oncotic pressure and/or alveolar protein degradation.
A Taxonomy of Abstract Form Using Studies of Synesthesia and Hallucinations
Authors: Betancourt Michael
Published: January 2007

The author proposes a taxonomy of abstract form anchored in an examination of the history and theory of synesthesia and abstract art. The foundations of this taxonomy lie in empirical psychological studies of “form-constants” found in cross-modal synesthetic visions and hallucinatory states, specifically the work of Heinrich Klüver in his examinations of mescaline and the mechanisms producing visual hallucinations. While the proposed taxonomy is limited only to synesthesia-inspired abstraction, it has suggestive possibilities when considered in relation to other forms of non-synesthetic abstraction such as Islamic Art, the geometric forms found on classical Greek vases, and other kinds of decorative abstract patterns.
Quality control of thermally modified timber: Interrelationship between heat treatment intensities and CIE L*a*b* color data on homogenized wood samples
Authors: Brischke Christian , Welzbacher Christian R. , Brandt Karin , Rapp Andreas Otto
Published: January 2007

There is increasing awareness of the durability, dimensional stability, and strength properties of thermally modified timber products. Appropriate standards and test methods for industrial-scale quality control are needed. The aim of this study was to investigate the suitability of CIE L*a*b* color measurements for implementation in industrial quality control. Good linear correlation was found between a cumulated measure of L* and b* data and the heat treatment intensity for spruce (Picea abies Karst.), pine (Pinus sylvestris L.), and beech (Fagus sylvatica L.). Wood samples homogenized by milling revealed less variation in color values compared to wood surface measurements. Thus, measurements on milled wood are recommendable to obtain results with high statistical significance. Color measurements are rapid, precise, and highly reproducible. Based on the strong correlation between color data and heat-treatment intensities, color measurements could easily be implemented for quality control of thermally modified timber.
Material properties and their interrelation in chemically modified clear wood of Scots pine
Authors: Epmeier Hannah , Johansson Marie , Kliger Robert , Westin Mats
Published: January 2007

The mechanical and physical properties of modified wood were assessed experimentally. Timber studs with a cross-section of 45 mm×70 mm were modified on a semi-industrial scale by four different methods: 1) acetylation (AC) with acetic anhydride; 2) modification with methylated melamine formaldehyde resin (MMF); 3) heat treatment in vegetable oil (HT); and 4) furfurylation (FA). Sapwood of Scots pine (Pinus sylvestris) with test specimen dimensions of 10×10×200 mm3 was investigated. A total of 2449 specimens were included in the study. The following properties and their correlations were studied: density, modulus of elasticity (MOEdyn) measured dynamically, equilibrium moisture content (EMC), and swelling behaviour. The properties were measured at humidity levels of 30%, 65%, and 90% RH, while the temperature was kept constant at 23°C. Significant changes in material properties took place. AC increased the density and reduced MOEdyn, EMC and swelling strain. FA increased the density and the swelling coefficient and reduced EMC and swelling strain. HT reduced the EMC, while MMF modification increased it.
Vision and Driving: Selective Effect of Optical Blur on Different Driving Tasks
Authors: Higgins Kent E. , Wood Joanne , Tait Alan
Published: January 2007

A test of static (high-contrast) visual acuity is the most prevalent vision test used to screen driver license applicants worldwide, even though research has largely failed to provide convincing empirical evidence for its role in traffic accidents. The purpose of this research was to evaluate the effect of visual acuity degradation on different components of the driving task. Participants were 24 young licensed drivers (15 men, 9 women) with normal vision. Driving performance was measured while participants wore modified swimmer's goggles to which blurring lenses were affixed in amounts necessary to produce binocular visual acuity levels of 20/20, 20/40 (the prevalent acuity standard for driving), 20/100, and 20/200. Driving performance was measured using the closed-road method of Wood and Troutbeck (1994). Acuity degradation produced significant decrements in road sign recognition and road hazard avoidance as well as significant increments in total driving time. Participants′ abilities to estimate whether clearances between pairs of traffic cones were sufficiently wide to permit safe passage of the vehicle and to slalom through a series of traffic cones were relatively unaffected by acuity degradation. Thus the latter tasks appear to be mediated by aspects of central and peripheral vision that are relatively unaffected by optical blur. Potential applications of this type of research include the development of procedures for defining empirically justifiable vision standards for driver licensure.
Effects of Sleep Deprivation and User Interface on Complex Performance: A Multilevel Analysis of Compensatory Control
Authors: Hockey G. Robert J. , Wastell David G. , Sauer Jürgen
Published: January 2007

This study was carried out to test the compensatory control model, which predicts performance maintenance under stress at the expense of effort and increased selectivity. It examined the effects of sleep deprivation on performance in an automated process control task based on a simplified life support system with two types of operator control panel interface: machine centered (M-C), in which access to the system was scheduled by the computer, and human-centered (H-C), in which access was ad-lib. The task environment also permitted the analysis of changes in strategy and in subsidiary activities (alarm reaction time, prospective memory). In a 2 × 2 repeated-measures design, 16 participants carried out the task with each interface after both normal sleep and one night of sleep deprivation (SD). No effects of SD were observed on primary task performance. As predicted, SD effects were confined to strategy changes and subsidiary task impairment and occurred only under the (low control) M-C interface. Subjective effort was increased under SD, with greater increases of effort associated with high levels of performance protection. The findings provide strong evidence in favor of the compensatory control model and argue for the use of complex, multilevel tasks in the analysis of performance under stress. Actual or potential applications include the development of more sensitive performance-testing systems based on multilevel analysis of decrement, and the design of interfaces for shift work and other suboptimal work conditions.
Driver Stress and Performance on a Driving Simulator
Authors: Matthews Gerald , Dorn Lisa , Hoyes Thomas W. , Davies D. Roy , Glendon A. Ian , Taylor Ray G.
Published: January 2007

Effects of stress on driving performance can depend on the nature of driver's stress reactions and on the traffic environment. In an experimental study, we assessed multiple dimensions of vulnerability to driver stress by a questionnaire that was validated in previous field studies and related those dimensions to performance on a driving simulator. Results were broadly consistent with prediction. A dimension of habitual dislike of driving was associated with reduced control skills, greater caution, and disturbance of moods. A measure of aggressive driving predicted more frequent and more error-prone overtaking, which are effects attributed to the use of confrontive coping strategies in interaction with other vehicles. An alertness measure predicted speed of reaction to pedestrian hazards. This research has practical applications for system design, automated monitoring of driver performance, selection and assessment of drivers, and training.
An Index of Dynamic Density
Authors: Smith Kip , Scallen Stephen F. , Knecht William , Hancock Peter A.
Published: January 2007

The risk of a collision between aircraft is rising as the density of commercial air traffic increases. This trend, together with the overwhelming need to upgrade the National Airspace System, has motivated the Federal Aviation Administration to sponsor the development of metrics to evaluate “dynamic density”—a proxy for the likelihood of collision risk. Here we propose and evaluate a mathematical index of dynamic density, D, that describes collision risk. Although our domain of investigation is aviation, the logic of D is applicable whenever objects move in limited spaces. A series of sensitivity analyses illustrate how D responds to frequently encountered air traffic conflict situations. We illustrate a use of D that characterizes pilot performance and efficiency in experimental simulations of free flight and suggest other human factors applications. This research could be applied immediately by the traffic management units of en-route air traffic control centers to reformulate the criterion for the critical capacity of sectors.
The complexities of reading capital in two Puerto Rican families
Authors: COMPTON‐LILLY CATHERINE
Published: January 2007

ABSTRACTS

Two case studies of adult GED (General Education Diploma) students and their kindergarten‐aged children are presented. The construct of “capital,” as described by Pierre Bourdieu (1986), is applied specifically to the children's and adults' reading practices. These case studies are analyzed in terms of various forms of official “reading capital” and locally valued reading and schooling practices. The results suggest that children and families possess rich resources that are often ignored, devalued, or denied in schools. The findings of this study challenge the applicability of Bourdieu's description of capital to local communities.

Se presentan dos estudios de caso de estudiantes adultos del GED y sus hijos en edad de asistir al preescolar. El concepto de “capital”, como lo describe Pierre Bourdieu (1986), se aplicó específicamente a las prácticas de lectura de los niños y los adultos. Estos estudios de caso se analizan en términos de varias formas de “capital de lectura” oficial y prácticas de lectura y escolaridad valoradas localmente. Los resultados sugieren que los niños y las familias poseen ricos recursos que a menudo se ignoran, devalúan o niegan en las escuelas. Los hallazgos de este estudio presentan un desafío a la validez de aplicar la descripción de capital de Bourdieu a las comunidades locales.

Zwei Untersuchungsstudien von Studenten der Erwachsenenausbildung GED (General Education Development) und ihren im Kindergartenalter befindlichen Kindern werden vorgestellt. Der Begriff von „Kapital,” wie durch Pierre Bourdieu (1986) beschrieben, ist bewußt auf Lesepraktiken von Kindern und Erwachsenen angewandt. Diese Untersuchungsstudien sind in Begriffen verschiedener Formen offiziellen „Lesekapitals” analysiert und in Lese‐ und Unterrichtspraktiken lokal geschätzt. Die Resultate lassen vermuten, dass Kinder und Familien reichliche Ressourcen besitzen, die in Schulen oft ignoriert, abgewertet oder vorenthalten werden. Die Erkenntnisse dieser Studie fordern die Anwendbarkeit von Bourdieus Beschreibung von Kapital für ortsgebundene Gemeinschaften heraus.

Ce texte présente deux études de cas portant sur des adultes préparant le diplôme de GED (Développement général en éducation) et leurs enfants d'âge préscolaire. Le concept de « capital », tel qu'énoncé par Pierre Bourdieu (1986), est appliqué spécifiquement aux pratiques de lecture des enfants et des adultes. Ces études de cas sont analysées en fonction des différentes formes du « capital lecture » officiel, de la lecture telle qu'elle est valorisée localement, et des practiques scolaires. Les résultats suggèrent que les enfants et les familles possèdent des ressources qui sont souvent ignorées, dévaluées ou niées au sein l'école. Les résultats de cette étude constituent un défi pour l'applicabilité de la description du capital de Bourdieu à des communautés locales.
Learning for non‐stationary Dirichlet processes
Authors: Quinn A. , Kárný M.
Published: January 2007

The Dirichlet process prior (DPP) is used to model an unknown probability distribution, F. This eliminates the need for parametric model assumptions, providing robustness in problems where there is significant model uncertainty. Two important parametric techniques for learning are extended to this non‐parametric context for the first time. These are (i) sequential stopping, which proposes an optimal stopping time for on‐line learning of F using i.i.d. sampling; and (ii) stabilized forgetting, which updates the DPP in response to changes in F, but without the need for a formal transition model. In each case, a practical and highly tractable algorithm is revealed, and simulation studies are reported. Copyright © 2007 John Wiley & Sons, Ltd.
An Improved Optical Method for Determining the Order Parameter in Thin Oriented Molecular Films and Demonstration of a Highly Axial Dipole Moment for the Lowest Energy π–π* Optical Transition in Poly(9,9‐ dioctylfluorene‐co‐bithiophene)
Authors: Gather M. C. , Bradley D. D. C.
Published: January 2007

Understanding the complex interplay between the 3D structural hierarchy within thin films of conjugated polymers and the properties of devices based thereon is starting to be recognized as an important challenge in the continued development of these materials for a range of applications. As a result, for example, accurate measurements of molecular orientation and elucidation of its influence on optical characteristics are of significant interest. Here we report an improved optical method to determine both the order parameter and the angle between the polymer backbone director and the optical transition dipole moment for the lowest energy π–π* absorption peak in uniaxially aligned thin films of conjugated polymers. The method uses a combination of polarized Raman spectroscopy and UV‐vis spectroscopy and is based on a general theoretical treatment to describe the expected Raman and optical absorption anisotropies of such films. It is applied to study the orientation within thermotropically aligned films of the electroluminescent fluorene‐based copolymer poly(9,9‐dioctylfluorene‐co‐bithiophene) (F8T2). A more highly axial transition dipole moment is found for the dominant long wavelength absorption peak of F8T2 compared to that of other fluorene‐based (co)polymers. The angle between the polymer backbone director and the transition dipole is estimated to be β ≤ 3°, a deduction that helps to explain the relatively large optical dichroism for aligned films of F8T2 and that offers the prospect of highly polarized electroluminescence from F8T2‐based light‐emitting diodes.
Growth of Heteroepitaxial ZnO Thin Films on GaN‐Buffered Al2O3 (0001) Substrates by Low‐Temperature Hydrothermal Synthesis at 90 °C
Authors: Kim J. H. , Kim E.‐M. , Andeen D. , Thomson D. , DenBaars S. P. , Lange F. F.
Published: January 2007

Heteroepitaxial ZnO films are successfully grown on nondoped GaN‐buffered Al2O3 (0001) substrates in water at 90 °C using a two‐step process. In the first step, a discontinuous ZnO thin film (ca. 200 nm in thickness) consisting of hexagonal ZnO crystallites is grown in a solution containing Zn(NO3)·6 H2O and NH4NO3 at ca. pH 7.5 for 24 h. In the second step, a dense and continuous ZnO film (ca. 2.5 μm) is grown on the first ZnO thin film in a solution containing Zn(NO3)·6 H2O and sodium citrate at ca. pH 10.9 for 8 h. Scanning electron microscopy, X‐ray diffraction, UV‐vis absorption spectroscopy, photoluminescence spectroscopy, and Hall‐effect measurement are used to investigate the structural, optical, and electrical properties of the ZnO films. X‐ray diffraction analysis shows that ZnO is a monocrystalline wurtzite structure with an epitaxial orientation relationship of (0001)[11$ \bar 2 $0]ZnO∥(0001)[11$ \bar 2 $0]GaN. Optical transmission spectroscopy of the two‐step grown ZnO film shows a bandgap energy of 3.26 eV at room temperature. A room‐temperature photoluminescence spectrum of the ZnO film reveals only a main peak at ca. 380 nm without any significant defect‐related deep‐level emissions. The electrical property of ZnO film showed n‐type behavior with a carrier concentration of 3.5 × 1018 cm–3 and a mobility of 10.3 cm2 V–1 s–1.
Fetal and maternalMTHFR C677Tgenotype, maternal folate intake and the risk of nonsyndromic oral clefts
Authors: Chevrier Cécile , Perret Claire , Bahuau Michel , Zhu Huiping , Nelva Agnès , Herman Christine , Francannet Christine , Robert‐Gnansia Elisabeth , Finnell Richard H. , Cordier Sylvaine
Published: January 2007

The association between maternal folate intake and risk of nonsyndromic oral clefts has been studied among many populations with conflicting results. The methylenetetrahydrofolate reductase gene (MTHFR)plays a major role in folate metabolism, and several polymorphisms, includingC677T, are common in European populations. Data from a French study (1998–2001) let us investigate the roles of maternal dietary folate intake and theMTHFRpolymorphism and their interaction on the risk of cleft lip with/without cleft palate (CL/P) and cleft palate only (CP). We used both case‐control (164 CL/P, 76 CP, 236 controls; 148, 59, 168 of whom, respectively, had an available genotype) and case‐parent (143 CL/P and 56 CP families) study designs and distinguished the role of the child's genotype and maternally mediated effects on risks. This study observed a beneficial effect of mothers' dietary folate intake on their offspring's risk (odds ratio (OR)≤230 µg/day = ref; for CL/P, OR[230–314 µg/day] = 0.56, 95% confidence interval = 0.3–0.9, OR>314 µg/day = 0.64, 0.4–1.1; for CP, OR[230–314 µg/day] = 1.15, 0.6–2.2, OR>314 µg/day = 0.70, 0.3–1.4). We observed a reduced risk associated with theTTgenotype of the child in the case‐control analysis (ORCC = ref; for CL/P, ORTT = 0.54, 0.3–1.1; for CP, ORTT = 0.33, 0.1–1.0); this genotype, either fetal or maternal, was not statistically significant in the case‐parent analysis. A frequency ofTTgenotype higher in our control group than previously reported in France can partly explain the risk reduction observed in case‐control comparison. Interactions were not statistically significant. Stratified case‐parent analysis showed, however, slight heterogeneity in the role ofTTgenotype according to folate intake. The modest sample size limits this study, which nonetheless provides new estimate of the possible impact of dietary folate intake andMTHFRpolymorphism on oral clefts. © 2007 Wiley‐Liss, Inc.
Informative phenotypes for genetic studies of psychiatric disorders
Authors: Szatmari Peter , Maziade Michel , Zwaigenbaum Lonnie , Mérette Chantal , Roy Marc‐Andre , Joober Ridha , Palmour Roberta
Published: January 2007

Despite its initial promise, there has been both progress and some set backs in genetic studies of the major psychiatric disorders of childhood and adulthood. Finding true susceptibility genes may be delayed because the most genetically informative phenotypes are not being used on a regular basis in linkage analysis and association studies. It is highly likely that using alternative phenotypes instead of DSM diagnostic categories will lead more rapid success in the search for these susceptibility genes. The objective of this paper is to describe the different types of informative phenotypes that can be employed in psychiatric genetic studies, to clarify their uses, to identify several methodologic issues the design and conduct of linkage and association studies that use alternative phenotypes and finally to suggest possible solutions to those difficulties. This is a conceptual review with a focus on methodological issues that may arise in psychiatric genetics and examples are taken from the literature on autism, schizophrenia, bipolar disorder, and alcoholism. © 2007 Wiley‐Liss, Inc.
“No one else sees the difference: ”family members' perceptions of changes in persons with preclinical Huntington disease
Authors: Williams Janet K. , Hamilton Rebekah , Nehl Carissa , McGonigal‐Kenney Meghan , Schutte Debra L. , Sparbel Kathleen , Birrer Emily , Tripp‐Reimer Toni , Friedrich Rose , Penziner Elizabeth , Jarmon Lori , Paulsen Jane
Published: January 2007

Manifestations of Huntington disease (HD) prior to clinical diagnosis are not well understood. This study documents adult family members' perceptions of changes and their attempts to manage these changes in persons who had received a positive predictive molecular HD test prior to clinical diagnosis. Data were obtained from 19 adult family members in six focus groups in the US and Canada and one individual interview in the US. Changes reported by family members included problems in cognition and behavior, which are consistent with prior reports. In addition, family members observed changes in motor functioning, the ability to complete usual activities at work or at home, and interpersonal relationships with family and friends. Family members attempted to manage these changes by taking on new responsibilities and preparing for future caregiving. Lack of information about preclinical HD, difficulty in understanding changes that may represent early stages of HD, and efforts to maintain secrecy of the preclinical HD situation contribute to compromising the abilities of family members to respond to changes in the person with preclinical HD. Findings provide insights into alterations in cognition, behavior, and functioning observed by the family members prior to clinical diagnosis. Findings further support the need for a more comprehensive assessment and management of early HD symptoms as well as support for family members. © 2007 Wiley‐Liss, Inc.
Innentitelbild: A Molecular Solomon Link (Angew. Chem. 1‐2/2007)
Authors: Pentecost Cari D. , Chichak Kelly S. , Peters Andrea J. , Cave Gareth W. V. , Cantrill Stuart J. , Stoddart J. Fraser
Published: January 2007

Ein molekularer Solomon‐Knoten wurde aus einer dynamischen Bibliothek molekularer Knoten durch kinetisch kontrollierte Kristallisation isoliert. Der Einführung gemischtmetallischer Template in das übliche Protokoll für die Synthese Borromäischer Ringe ermöglichte es J. F. Stoddart et al., eine molekulare Solomon‐Verknüpfung als einziges kristallines Produkt unter den beschriebenen Reaktionsbedingungen zu erhalten; sie konnten dessen Struktur röntgenographisch ermitteln, wie sie in ihrer Zuschrift auf S. 222 ff. schildern.
Inside Cover: Oligothiophene‐Based Catenanes: Synthesis and Electronic Properties of a Novel Conjugated Topological Structure (Angew. Chem. Int. Ed. 3/2007)
Authors: Bäuerle Peter , Ammann Martin , Wilde Markus , Götz Günther , Mena‐Osteritz Elena , Rang Alexander , Schalley Christoph A.
Published: January 2007

A “π‐conjugated catenane” or more accurately a catenane formed from two intertwined conjugated macrocycles has been formed for the first time by a double metal template strategy. Interestingly, a through‐space electronic interaction between the donor unit (oligothiophene, metallic color) and the acceptor component of the other ring (phenanthroline, blue) is evident. Further details can be found in the Communication by P. Bäuerle et al. on page 363ff.
Role of aromatic amino acids in protein–nucleic acid recognition
Authors: Baker Christopher M. , Grant Guy H.
Published: January 2007

Statistical analysis of structures from the PBD has been used to examine the role that the aromatic amino acids play in protein–nucleic acid recognition. In protein–DNA complexes, the residues Phe and His are found to bind selectively to the DNA chain—Phe to A and T, and His to T and G. The preferred binding modes are identified, and the interactions involving Phe are shown to be important in the transcription process. In protein–RNA complexes, Phe is found to occur far less often and is instead replaced by Trp, which binds selectively to C and G, offering a possible mechanism for differentiation between the two nucleic acids. SASA analysis of the two sets of complexes suggests that all of the aromatic amino acids are more heavily involved in binding than would be expected on the balance of probability. Phe and Tyr occur approximately equal in both sets of data, whereas the proportions of His and Trp vary considerably, supporting the idea that these residues may be involved in differentiating between the two nucleic acids. © 2007 Wiley Periodicals, Inc. Biopolymers 85: 456–470, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Rapid responses of ribosomal RNA synthesis to nutrient shifts
Authors: Suthers Patrick F. , Gourse Richard L. , Yin John
Published: January 2007

A major challenge in systems biology is to integrate our mechanistic understanding of gene regulation to predict quantitatively how cells will respond to environmental changes. Living cells respond rapidly to the availability of nutrients in part by altering production of ribosomal RNA (rRNA), a limiting component in the biosynthesis of ribosomes. Studies of rRNA transcription by the RNA polymerase of Escherichia coli have identified regulatory roles for guanosine tetraphosphate (ppGpp), the initiating nucleotide, and the protein DksA. To what extent findings from in vitro studies can be used to quantitatively predict in vivo responses to changing nutrient environments is unknown. We developed a mechanistic mathematical model for rRNA transcriptional responses to such changes. Our model accounts for binding of RNAP to its rRNA promoter to form a closed complex, isomerization from a closed complex to an open complex, reversible incorporation of the initiating NTP (iNTP), transcript elongation, and clearance of the promoter. Further, the model incorporates interactions between ppGpp and DksA with transcription intermediates, and it includes an empirical correction to account for salt effects. The model biophysical parameters were determined using 33 single‐ and multi‐round transcription experiments spanning 487 in vitro measurements. By incorporating in vivo measurements of ppGpp and ATP, the model correctly predicted rRNA production rates for cellular responses to nutrient upshifts, downshifts, and outgrowth into fresh medium. Inclusion of DksA was essential in all three cases. Our work provides a foundation for using data‐driven computational models to predict the kinetics of in vivo transcriptional responses. Biotechnol. Bioeng. 2007; 97: 1230–1245. © 2007 Wiley Periodicals, Inc.
Comparisons of optical pH and dissolved oxygen sensors with traditional electrochemical probes during mammalian cell culture
Authors: Hanson Michael A. , Ge Xudong , Kostov Yordan , Brorson Kurt A. , Moreira Antonio R. , Rao Govind
Published: January 2007

Small‐scale upstream bioprocess development often occurs in flasks and multi‐well plates. These culturing platforms are often not equipped to accurately monitor and control critical process parameters; thus they may not yield conditions representative of manufacturing. In response, we and others have developed optical sensors that enable small‐scale process monitoring. Here we have compared two parameters critical to control in industrial cell culture, pH and dissolved oxygen (DO), measured with our optical sensors versus industrially accepted electrochemical probes. For both optical sensors, agreement with the corresponding electrochemical probe was excellent. The Pearson Correlations between the optical sensors and electrochemical probes were 98.7% and 99.7%, for DO and pH, respectively. Also, we have compared optical pH sensor performance in regular (320 mOsm/kg) and high‐osmolality (450 mOsm/kg) cell culture media to simulate the increase in osmolality in pH‐controlled cultures. Over a pH range of 6.38–7.98 the average difference in pH readings in the two media was 0.04 pH units. In summary, we have demonstrated that these optical sensors agree well with standard electrochemical probes. The accuracy of the optical probes demonstrates their ability to detect potential parameter drift that could have significant impact on growth, production kinetics, and protein product quality. We have also shown that an increase in osmolality that could result from controlling pH or operating the reactor in fed‐batch mode has an insignificant impact on the functionality of the pH patches. Biotechnol. Bioeng. 2007;97: 833–841. © 2007 Wiley Periodicals, Inc.
Cell patterning using magnetite nanoparticles and magnetic force
Authors: Ino Kosuke , Ito Akira , Honda Hiroyuki
Published: January 2007

Technologies for fabricating functional tissue architectures by patterning cells precisely are highly desirable for tissue engineering. Although several cell patterning methods such as microcontact printing and lithography have been developed, these methods require specialized surfaces to be used as substrates, the fabrication of which is time consuming. In the present study, we demonstrated a simple and rapid cell patterning technique, using magnetite nanoparticles and magnetic force, which enables us to allocate cells on arbitrary surfaces. Magnetite cationic liposomes (MCLs) developed in our previous study were used to magnetically label the target cells. When steel plates placed on a magnet were positioned under a cell culture surface, the magnetically labeled cells lined on the surface where the steel plate was positioned. Patterned lines of single cells were achieved by adjusting the number of cells seeded, and complex cell patterns (curved, parallel, or crossing patterns) were successfully fabricated. Since cell patterning using magnetic force may not limit the property of culture surfaces, human umbilical vein endothelial cells (HUVECs) were patterned on Matrigel, thereby forming patterned capillaries. These results suggest that the novel cell patterning methodology, which uses MCLs, is a promising approach for tissue engineering and studying cell–cell interactions in vitro. Biotechnol. Bioeng. 2007; 97: 1309–1317. © 2007 Wiley Periodicals, Inc.
A multi‐step kinetic model for substrate assimilation and bacterial growth: Application to benzene biodegradation
Authors: Bordel S. , Muñoz R. , Díaz L.F. , Villaverde S.
Published: January 2007

A multi‐step kinetic model based on the concept of synthesizing unit (SU) was developed for describing benzene biodegradation in Pseudomonas putida F1. The model herein presented considered substrate arrival rates to the SU rather than concentrations, and provided a reasonable good fit of the dynamics of both catechol and biomass concentrations experimentally determined. It was based on very general assumptions and could be applied to any process accumulating metabolic intermediates. Conventional growth models considering a single step can be regarded as a particular case of this multi‐step model. Despite the merits of this model, its applicability strongly depends on the knowledge of the complex induction‐repression and inhibition mechanisms governing the different catabolic steps of the degradation pathway, which in most cases are difficult to elucidate experimentally and/or to model mathematically. In this particular case repression of benzene oxidation by catechol and self‐inhibition of catechol transformation were experimentally confirmed and considered in the simulation, resulting in a good fit (relative average error of 6%) of the experimental data. Biotechnol. Bioeng. 2007; 97: 1098–1107. © 2007 Wiley Periodicals, Inc.
Complexation of Fatty Acids and Fatty Acid‐CoAs with Synthetic O‐Methylated Polysaccharides
Authors: Cheon Hwan‐Sung , Wang Yonghui , Ma Jianguo , Kishi Yoshito
Published: January 2007

An experimentally simple, but highly reproducible and reliable method has been developed to follow the complexation event of fatty acid (FA) and FA‐CoA with polysaccharides. This method was based on the recent discovery of the unique blue‐shifted UV absorption associated with the aggregation of tetraenoic fatty acids (TE‐FAs) in aqueous solution. Complexation was monitored by recording the intensity of UV absorption at 250 nm ([free TE‐FA]) and 303 nm ([complexed TE‐FA]), and the K aggregate of C20 t,t,t,t‐TE‐FA exhibited the ideal property for this purpose. Synthetic 3‐O‐methyl‐D‐mannose‐ and 6‐O‐methyl‐D‐glucose‐containing lipopolysaccharides were found to exhibit a broad range of the binding affinities with C20 t,t,t,t‐TE‐FAs as well as saturated FAs/FA‐CoAs.
Influence of citric acid on calcium sulfate dihydrate crystallization in aqueous media
Authors: Titiz‐Sargut S. , Sayan P. , Avcı B.
Published: January 2007

The crystallization of Calcium sulfate dihydrate produced by the reaction between pure Ca(OH)2 suspension and H2SO4 solution was investigated at different pH values, temperatures and citric acid concentrations. Crystal size distributions, filtration rates and zeta potentials of gypsum were determined as a function of citric acid concentrations at pH 3.5 and 65°C. The influence of citric acid on the morphology of gypsum was also investigated and discussed. The average particle size of gypsum was reached to maximum in the presence of approximately 2500 ppm citric acid concentration, where the minimum cake resistance and maximum filtration rate were obtained. In the presence of citric acid, various crystal morphologies such as tabular, plate‐like, double‐taper leaf‐like and flower‐like, etc., were obtained. The change of morphology is related to the preferential adsorption of citric acid on different crystallographic faces. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental study of bubble generation during β‐BaB2O4 single crystal growth
Authors: Pan X. H. , Jin W. Q. , Ai F. , Liu Y. , Hong Y.
Published: January 2007

The generation of bubble‐inclusions during BaB2O4 (BBO) crystal growth from high temperature solution has been optically observed by an in situ observation technique. It was found that bubbles are formed from the peripheries of some hexagonal defects in the (0001) plane of the growing crystal, which may be caused by the evaporation of the air‐opened interface at the high temperature. In addition, atomic force microscope (AFM) was used to investigate the distribution of bubbles. Results revealed that the bubble generation and distribution depend strongly on the microscopic structure of the interface: on a rough interface, bubbles are easily formed and grow rapidly; however, they are greatly suppressed by step trains on a vicinal interface. In the latter case, the height value of a bubble is close to that of the step, which is in the order of several tens of nanometers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and magnetic properties of lanthanum orthovanadate nanorods
Authors: Wang Nian , Zhang Quanfei , Chen Wen
Published: January 2007

In the present paper, single‐crystalline lanthanum orthovanadate (LaVO4) nanorods were synthesized by an ethylenediaminetetraacetic acid (EDTA)‐mediated hydrothermal method. The resulting products were characterized using XRD, SEM, TEM and HRTEM. The experimental results illustrated that the morphologies and microstructures of LaVO4 nanorods were influenced by EDTA and pH value of the precursor solution. The magnetic properties measurements showed that the magnetocrystalline anisotropy was greatly strengthened by the strong effect of the one‐dimensional anisotropy, and the magnetic properties of LaVO4 nanorods are better than that of LaVO4 nanoparticles. The growth mechanism of LaVO4 nanorods was also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure, thermal and compositional deformations of β‐CsB5O8
Authors: Bubnova R. , Dinnebier R. E. , Filatov S. , Anderson J.
Published: January 2007

The crystal structure of β‐CsB5O8 has been determined from X‐ray powder diffraction data using synchrotron radiation: Pbca, a = 7.8131(3) Å, b = 12.0652(4) Å, c = 14.9582(4) Å, Z = 8, ρcalc = 2.967 g/cm3, R‐p = 0.076, R‐wp = 0.094. β‐CsB5O8 was found to be isostructural with β‐KB5O8 and β‐RbB5O8. The crystal structure consists of a double interlocking framework built up from B‐O pentaborate groups. The crystal structure exhibits a highly anisotropic thermal expansion: αa = 53, αb = 16, αc = 14 · 10‐6/K; the anisotropy may be caused by partial straightening of the screw chains of the pentaborate groups. The similarity of the thermal and compositional (Cs‐Rb‐K substitution) deformations of CsB5O8 is revealed: increasing the radius of the metal by 0.01 Å leads to the same deformations of the crystal structure as increasing the temperature by 35°C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical and magnetotransport properties of La0.7Sr0.3MnO3/TiO2 composites
Authors: Gaur A. , Varma G. D.
Published: January 2007

The composite samples with nominal compositions of (1‐x) La0.7Sr0.3MnO3 + x TiO2 (x = 0, 0.05, 0.10, 0.15 and 0.20) were synthesized via solid state reaction process. The X‐ray diffraction and scanning electronic microscopy observations reveal no reaction between La0.7Sr0.3MnO3 (LSMO) and TiO2 phases. Temperature dependence resistivity measurements show that TiO2 phase shifts the metal‐insulator transition temperature (Tp) towards lower temperature and increases the resistivity. Moreover, the magnetization of the composite samples decreases with TiO2 content. An enhancement in magnetoresistance is observed in the composite samples with x = 0.05 and x = 0.10 at low magnetic fields, which is encouraging for potential application of magnetoresistive materials at low field. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐pumped phase conjugation in CSBN75 crystals
Authors: Gao Ch. Y. , Xia H. R. , Xu J. Q. , Si Sh. Ch. , Ran D. G. , Ling Z. Ch. , Zhang H. J. , Wang J. Y. , Song H. L.
Published: January 2007

The self‐pumped phase conjugation in CSBN75 is studied in this investigation basing on an anti‐traditional method, which using part laser spot to irradiate crystal. With the change of the spot size projected on the crystal, the deformed laser spot that introduced by self‐pumped phase conjugation and its complementary pattern are distinctly displayed on the screen. Tentative analysis is executed in this paper. However, it will be applied in optical information processing with these crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of semi organic nonlinear optical LHPCL crystals
Authors: Aruna S. , Vimalan M. , Thomas P. C. , Thamizharasan K. , Ambujam K. , Madhavan J. , Sagayaraj P.
Published: January 2007

The growth of single crystals of L‐histidinium perchlorate (LHPCL), a semi organic nonlinear optical material with dimension upto 5 × 6 × 2.5 mm3 is reported. Good optical quality single crystals were grown from aqueous solution by slow solvent evaporation technique. The grown crystals were characterized by single crystal X‐ray diffraction (XRD), FT‐IR and optical transmission studies. Thermal studies confirm that LHPCL has a fairly high thermal stability (272°C) when compared with other members of histidine family. The scanning electron microscopy (SEM) provides information on the quality of the samples and grain distribution over the surface of the sample. The dielectric constant and dielectric loss of the compound were measured at different frequencies, and also at varying temperatures and the results of these experiments are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intercalation and anisotropy of optical absorption in MoRe0.005Se1.995 single crystals
Authors: Vora Mihir M. , Vora Aditya M.
Published: January 2007

The optical energy gap of MoRe0.005Se1.995 single crystal has been measured at room temperature near the fundamental absorption method. The incident light was polarized along c‐axis of the crystals. Two and three dimensional models are adopted for generating the results. Direct as well as indirect transitions are involved in the absorption process. The indirect transition was found to be allowed with two phonons involved in the process. The three dimensional model could be used to describe the optical properties of the single crystal of MoRe0.005Se1.995. Also, the optical energy gaps depend upon the amount of the intercalating Re material, which show the anisotropy of the chemical bonds. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoacoustic studies on two new organic NLO materials: L‐threonine and L‐prolinium tartrate
Authors: Britto Dhas S. A. Martin , Suresh M. , Raji P. , Ramachandran K. , Natarajan S.
Published: January 2007

Photoacoustic spectroscopy (PAS) is a non‐destructive testing (NDT) tool and used here for analyzing the physical properties such as thermal diffusivity, thermal diffusion length, thermal conductivity and thermal effusivity of L‐Threonine and L‐Prolinium tartrate. These two crystals belong to a group of recently developed NLO materials, in our laboratory. The single crystals of the two compounds were grown by using submerged seed solution growth method. Characterization of the crystals was made by using single crystal X‐ray diffraction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective expression of Bhlhb5 in subsets of early‐born interneurons and late‐born association neurons in the spinal cord
Authors: Liu Ben , Liu Zijing , Chen Tao , Li Hong , Qiang Boqin , Yuan Jiangang , Peng Xiaozhong , Qiu Mengsheng
Published: January 2007

Accumulating evidence has suggested that the basic helix‐loop‐helix transcription factors play important roles in controlling neuronal fate specification and differentiation in the developing central nervous system. In this study, we report a detailed immunological study on the expression of Bhlhb5 in embryonic mouse spinal cord with a newly developed antibody. At the early stage of neural development, Bhlhb5 is specifically expressed in dI6 dorsal interneurons and in V1 and V2 ventral interneurons. At late stages of development, Bhlhb5 expression is detected in a subset of late‐born dorsal association interneurons that migrate into the uppermost layer of the dorsal horn. Developmental Dynamics 236:829–835, 2007. © 2007 Wiley‐Liss, Inc.
IL‐18, but not IL‐12, is required for optimal cytokine production by influenza virus‐specific CD8+ T cells
Authors: Denton Alice E. , Doherty Peter C. , Turner Stephen J. , La Gruta Nicole L.
Published: January 2007

The potent innate cytokines IL‐12 and IL‐18 are considered to be important antigen‐independent mediators of IFN‐γ production by NK cells and T lymphocytes. The present analysis addresses the physiological role of IL‐12 and IL‐18 in the generation of virus‐specific CD8+ T cells. Both wt C57BL/6J (B6) mice and mice with disrupted IL‐12p40 (IL‐12p40–/–) or IL‐18 (IL‐18–/–) genes were infected with an influenza A virus and the characteristics of the resultant epitope‐specific CD8+ T cell responses were compared. While IL‐12 appeared to have no notable effect on either virus growth or on CD8+ T cell response profiles, the absence of IL‐18 was associated with delayed virus clearance from the lung and, despite normal numbers, a significantly reduced production of IFN‐γ, TNF‐α, and IL‐2 by epitope‐specific CD8+ T cells. While this cytokine phenotype was broadly maintained in IL‐12p40/IL‐18 double‐knockout mice, no evidence was seen for any additive effect. Together, our results suggest that IL‐18, but not IL‐12, induces optimal, antigen‐specific production of key cytokines by CD8+ T cells for the efficient clearance of influenza virus from the lungs of infected mice.
Combining data from multiple years or areas to improve variogram estimation
Authors: Walter John F. , Christman Mary C. , Hoenig John M. , Mann Roger
Published: January 2007

A requirement for geostatistical prediction is estimation of the variogram from the data. Often low sample size is a major impediment to elucidating a variogram even for a highly autocorrelated spatial process. This paper presents a methodology for improving variogram estimation when samples exist from multiple years or regions sharing a similar process for generating spatial autocorrelation. Such samples may come from annual monitoring programs for natural resources or from multiple geologic regions. As each set of samples contains some information on the spatial autocorrelation, combining information through the construction of a combined variogram cloud and binning to obtain a common variogram improves the estimation of the variogram. In both simulations and in real datasets of oyster abundance the method proposed here reduces the likelihood of failing to obtain a variogram from a set of samples and improves the efficiency of variogram estimation. In practice, the benefits obtained by estimating an otherwise elusive variogram generally outweigh the costs of using a slightly incorrect variogram model if different sampling stanzas are combined when they do not share the same spatial autocorrelation. Copyright © 2007 John Wiley & Sons, Ltd.