bluuebunny/crossref_metadata_2025 huggingface dataset:
Der Lindenbaum in der deutschen Literatur des 18. und 19. Jahrhunderts
Authors: Hentschel Uwe
Published: September 2005

‘‘Linden, die grünen Muhmen der deutschen Eichen…’’1

Lange galt die Eiche unter den Deutschen als der Baum, der ihr Wesen idealiter repräsentierte. Doch neben den zumeist kriegerischen Gesängen, in denen die Kraft, der Bestand und die eherne Festigkeit des Eichenbaums symbolisch für die eigene nationale Selbstdarstellung beansprucht wurde, existierte immer schon eine Baum‐Dichtung, in der konterkarierend bzw. ergänzend auf eine andere Seite deutscher Mentalität hingewiesen wurde.

Die Linde mit ihren herzförmigen Blättern und ihrem narkotisierenden Blütenduft wurde schon im Mittelalter als Baum der Liebe und der Leidenschaft besungen, wovon nicht zuletzt das Lied Under der linden an der heide, da unser zweier Bette was von Walter von der Vogelweide ein beredtes Zeugnis ablegt. Und so wurde der Baum auch später von den Dichtern immer wieder aufgerufen, wenn es darum ging, Verlangen, Zuneigung, aber auch Trennung und Tod der Liebenden nacherlebbar zu gestalten.

Im 18. Jahrhundert gehörte der Lindenbaum zum festen Bestandteil der Idyllendichtung; von ihm machten Johann Heinrich Voß und Goethe gleichermaßen Gebrauch. Letzterer gab in seinen wirkungsmächtigen Werken Die Leiden des jungen Werthers und Hermann und Dorothea Beispiele dafür, wie mit Hilfe des Baumes eine idyllische bzw. eine erhabene Stimmung erzeugt werden kann. Die Literatur der Aufklärung bis hin zur Romantik verweist auf die herausgehobene Bedeutung der Linde in der bürgerlichen Alltagskultur, zugleich steht sie besonders im 19. Jahrhundert – exemplarisch sei auf Wilhelm Müllers Der Lindenbaum verwiesen – für die Sehnsucht nach Geborgenheit in einer Welt von moderner Zerissenheit und Entfremdung. Und so setzt die Linde ganz im Gegensatz zur ‘‘martialischen’’ Eiche einen anderen, mentalitätsgeschichtlich bedeutsamen Charakterzug der Deutschen ins Bild, den des romantisch liebenden Bürgers.
Common variations in the pretest environment influence genotypic comparisons in models of anxiety
Authors: Izídio G. S. , Lopes D. M. , Spricigo L. , Ramos A.
Published: September 2005

The behavioral characterization of rodent strains in different studies and laboratories can provide unreplicable results even when genotypes are kept constant and environmental control is maximized. In the present study, the influence of common laboratory environmental variables and their interaction with genotype on the results of behavioral tests of anxiety/emotionality were investigated. To this end, the inbred rat strains Lewis (LEW) and spontaneously hypertensive rats (SHR), which are known to differ for numerous emotionality‐related behaviors, were tested in the open field (OF), elevated plus maze (EPM) and black/white box (BWB), while three environmental factors were systematically controlled and analyzed: (1) the experimenter handling the animal (familiar or unfamiliar); (2) the position of the home cage (top or bottom shelf of the rack) and (3) the behavioral state of the animal immediately before the test (arousal or rest). Experimenter familiarity did not alter the behavior of rats in the OF. Cage position, on the other hand, influenced the behavior in the OF and BWB, with rats housed in top cages appearing less anxious like than those housed in the bottom. In the BWB (but not in the OF), these effects were genotype dependent. Finally, the behavioral state of the animals prior to testing altered the results of the EPM in a strain‐dependent manner, with some anxiety‐related genotypic differences being found only among rats that were aroused in their home cages. This study showed that common variations in the laboratory environment interact with genotype in behavioral tests of anxiety/emotionality. Recognizing and understanding such variations can help in the design of more effective experiments.
Altered anxiety‐related and social behaviors in the Fmr1 knockout mouse model of fragile X syndrome
Authors: Spencer C. M. , Alekseyenko O. , Serysheva E. , Yuva‐Paylor L. A. , Paylor R.
Published: September 2005

The loss of fragile X mental retardation (FMR1) gene function causes fragile X syndrome (FXS), a common mental retardation syndrome. Anxiety and abnormal social behaviors are prominent features of FXS in humans. To better understand the role of FMR1 in these behaviors, we analyzed anxiety‐related and social behaviors in Fmr1 knockout (KO) mice. In the mirrored chamber test, Fmr1 KO mice showed greater aversion to the central mirrored chamber than wild‐type (WT) littermates, suggesting increased anxiety‐like responses to reflected images of mice. Fmr1 KO mice exhibited abnormal social interactions in a tube test of social dominance, winning fewer matches than WT littermates. In a partition test, Fmr1 KO mice had normal levels of social interest and social recognition. However, during direct interaction tests, Fmr1 KO mice showed significant increases in sniffing behaviors. We further tested the influence of environmental familiarity on the social responses of Fmr1 KO mice to unfamiliar partners. In unfamiliar partitioned cages, Fmr1 KO mice did not differ from WT mice in investigation of unfamiliar partners. However, in familiar partitioned cages, Fmr1 KO mice showed less investigation of a newly introduced partner during the first 5 min and more investigation during the last 5 min of a 20‐min partition test, behaviors consistent with initial social anxiety followed by enhanced social investigation. Our findings indicate that the loss of Fmr1 gene function results in altered anxiety and social behavior in mice and demonstrate that the Fmr1 KO mouse is a relevant animal model for the abnormal social responses seen in FXS.
Writes of Passage: Writing an Empirical Journal Article
Authors: White Lynn
Published: September 2005

This article provides advice about preparing research reports for submission to professional journals in general and Journal of Marriage and Family in particular. In addition to working through all the major parts of a research paper, I provide some general advice about writing, editing, and revising. The article is intended to help new professionals improve the quality of their journal submissions and the likelihood of successful publication.
Toward a Conceptualization of Perceived Work‐Family Fit and Balance: A Demands and Resources Approach
Authors: Voydanoff Patricia
Published: September 2005

Using person‐environment fit theory, this article formulates a conceptual model that links work, family, and boundary‐spanning demands and resources to work and family role performance and quality. Linking mechanisms include 2 dimensions of perceived work‐family fit (work demands–family resources fit and family demands–work resources fit) and a global assessment of perceived work‐family balance. Work, family, and boundary‐spanning demands and resources are associated with the 2 dimensions of fit, which combine with boundary‐spanning strategies to influence work‐family balance, which in turn affects role performance and quality. The model provides a framework for clarifying and integrating previous conceptualizations, measures, and empirical research regarding perceived work‐family fit and balance as linkages between the work‐family interface and outcomes. The article closes with suggestions for further work.
Families in the Life Course: Interdependency of Roles, Role Configurations, and Pathways
Authors: Macmillan Ross , Copher Ronda
Published: September 2005

Families are central in the unfolding life course. They have both internal and external dynamics that reflect and characterize the modern life span, and a life course perspective has particular utility for understanding the role and implications of families for individuals and society. The purpose of this paper is 3‐fold. First, we offer a family life course perspective that delineates core concepts of roles, role configurations, and pathways, specifies the links between them, and highlights the importance of linked lives and structural context. Second, we elaborate a latent class approach for modeling the multilayered dynamic interdependencies that characterize modern family life. Third, we provide an empirical example by considering the timing of childbearing, teen parenthood, and its place in the transition to adulthood using women's data from the National Longitudinal Survey of Youth 1979 (N= 2,191). We conclude by discussing further avenues of family research that are enhanced with a life course approach and complementary latent structure methodology.
Secondary Data Analysis in Family Research
Authors: Hofferth Sandra L.
Published: September 2005

This article first provides an overview of the part that secondary data analysis plays in the field of family studies in the early 21st century. It addresses changes over time in the use of existing omnibus data sets and discusses their advantages and disadvantages. The second part of the article focuses on the elements that make a study a “family” study. It describes sources of existing data and the process of selecting a data set. The third part presents special issues and concerns in using existing data, and the fourth part addresses the future of secondary data analysis in the field of family research.
Small Samples, Big Challenges: Studying Atypical Family Forms
Authors: Cheng Simon , Powell Brian
Published: September 2005

We discuss the challenges of small‐subsample sizes that family scholars often encounter when studying nontraditional or less common family types. We begin by identifying the general difficulties of using existing data in this line of research and then discuss potential solutions that may help researchers to avoid these problems. Using data from the Early Childhood Longitudinal Study, we use the example of monoracial White, monoracial Asian, and Asian/White interracial families to illustrate these problems and available, albeit imperfect, solutions.
Action‐Oriented Research: Strategies for Engaged Scholarship
Authors: Small Stephen A. , Uttal Lynet
Published: September 2005

Action‐oriented research is a methodological approach for doing collaborative research with practitioners and community partners that can inform practice, programs, community development, and policy while contributing to the scientific knowledge base. This article discusses how family scholars can use action‐oriented research to work together with community partners to address their need for useful information about their practices and programs. We present some practical strategies that can help guide the action‐oriented research process including how to develop collaborative relationships with community partners; suggestions for determining sound, action‐oriented research questions; guidelines for selecting and implementing appropriate research designs; and considerations regarding data collection and the dissemination of findings.
Two‐Wave Panel Analysis: Comparing Statistical Methods for Studying the Effects of Transitions
Authors: Johnson David
Published: September 2005

Study of the effect of transitions on individual and family outcomes is central to understanding families over the life course. There is little consensus, however, on the appropriate statistical methods needed to study transitions in panel data. This article compares lagged dependent variable (LDV) and change score (CS) methods for analyzing the effect of events in two‐wave panel data. The methods are described, and their performances are compared both with a simulation and a substantive example using the National Survey of Families and Households two‐wave panel. The results suggest that CS methods have advantages over LDV techniques in estimating the effect of events on outcomes in two‐wave panel data.
Toward Disentangling Fathering and Mothering: An Assessment of Relative Importance
Authors: Stolz Heidi E. , Barber Brian K. , Olsen Joseph A.
Published: September 2005

This study employed dominance analysis to assess the relative importance of maternal and paternal support, behavioral control, and psychological control in explaining depression, antisocial behavior, and social initiative within 644 adolescents. We noted the lack of replicated findings concerning differential effects of mothers and fathers and employed an approach that considered mothers’ and fathers’ overlapping predictive abilities in determining their relative importance. Results lend support to the overall parental framework and additionally suggest (a) mothers’ behavioral control is relatively more important than fathers’ in explaining sons’ subsequent antisocial behavior, (b) fathers’ support is relatively more important than mothers’ support in explaining subsequent youth social initiative, and (c) mothering and fathering tend to have a cross‐gendered effect on early adolescents’ depression.
Protective Effect of Volatile Oil, Alcoholic and Aqueous Extracts ofOriganum majoranaon Lead Acetate Toxicity in Mice
Authors: El‐Ashmawy Ibrahim M. , El‐Nahas Abeer F. , Salama Osama M.
Published: September 2005

Abstract:Natural dietary antioxidants are extensively studied for their ability to protect cells from miscellaneous damages.Origanum majoranaL., Lamiaceae, is a potent antioxidant. The effect of administration ofO. majorana(volatile oil, alcoholic and aqueous extracts) on oral administration of lead acetate in the diet of mice at concentration 0.5% (W/W) for one month were studied by measuring serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), urea and creatinine, histopathological changes of the liver and kidney and genotoxicity including, rate of micronucleus and chromosomal aberrations in bone marrow cells. Mice were treated with the 3 different forms ofO. majorana, one month before and maintained with lead acetate administration. The 3 forms ofO. majoranainduced a significant decrease in serum activities of transaminases (AST & ALT), ALP, urea and creatinine and improved the liver and kidney histology in comparison with lead acetate treated group. Alcoholic extracts ofO. majoranasignificantly reduced the rate of micronucleus, number of aberrant cells and different kinds of chromosomal aberrations. Volatile oil extract significantly reduced the rate of micronucleus and chromosomal fragments. Aqueous extract and volatile oil also ofO. majoranasignificantly reduced number of gaps, ring chromosome and stickiness. It could be concluded thatO. majoranaplays an important role in ameliorating liver and kidney functions and genotoxicity induced by lead toxicity.
Comparative Appraisal of Clodronate, Aspirin and Dexamethasone as Agents Reducing Alendronate‐induced Inflammation in a Murine Model
Authors: Yu Zhiqian , Funayama Hiromi , Deng Xue , Kuroishi Toshinobu , Sasano Takashi , Sugawara Shunji , Endo Yasuo
Published: September 2005

Abstract: Among the bisphosphonates, the nitrogen‐containing bisphosphonates have much stronger anti‐bone‐resorptive activities than bisphosphonates containing no nitrogen, but nitrogen‐containing bisphosphonates mostly have inflammatory side effects. Our previous murine‐model experiments with a single intraperitoneal bisphosphonate injection demonstrated that (i) nitrogen‐containing bisphosphonates induce various inflammatory reactions via an IL‐1‐dependent mechanism, (ii) alendronate (an nitrogen‐containing bisphosphonate) produces a clear sclerotic line in the tibia that is easily detectable by radiography a few weeks later (tentatively called the bisphosphonate line, a useful marker for the anti‐bone‐resorptive activities of bisphosphonates), and (iii) clodronate (a non‐nitrogen‐containg bisphosphonate) reduces the inflammatory reactions induced by alendronate but does not reduce the bisphosphonate line formation induced by alendronate. We compared the effects of clodronate, aspirin and dexamethasone on the inflammatory reactions induced by alendronate (40 μmol/kg) (induction of the histamine‐forming enzyme, accumulation of pleural exudate and splenomegaly) and on the bisphosphonate line formation induced by alendronate (0.1 μmol/kg). The effects of aspirin (833 μmol/kg) were weak. However, like clodronate, dexamethasone (10 μmol/kg, injected 5 min. after alendronate), strongly inhibited the alendronate‐induced inflammatory reactions but did not reduce the alendronate‐induced bisphosphonate line formation. Alendronate produced normal bisphosphonate lines in IL‐1‐deficient mice, too. These results suggest that clodronate and/or dexamethasone may be suitable for preventing or reducing the inflammatory side effects of nitrogen‐containing bisphosphonates while preserving their powerful anti‐bone‐resorptive activities (although in practice the known side effects of dexamethasone may limit its use), and that the anti‐bone resorptive activities of nitrogen‐containing bisphosphonates are not influenced by IL‐1.
Effects of Feed Restriction on the Nucleolar Structure and Function in Lymphocytes
Authors: Berger Josef , Machackova Martina , Berger Zdenek
Published: September 2005

Abstract: Since malnutrition leads to adverse effects of several drugs on haemopoiesis and blood morphology, we tested if malnutrition itself could affect the nucleolar structure and function in rat lymphocytes. We report changes in the proportion of different nucleolar types that were dependent on the severity of feed restriction. The observed changes resemble those seen with cytostatics suggesting a possible link between feed restriction and haemotoxicity.
Phenomenon of Hepatic Overload of Copper inMugil cephalus: Role of Metallothionein and Patterns of Copper Cellular Distribution
Authors: Linde Ana Rosa , Klein Dominik , Summer Karl Heinz
Published: September 2005

Abstract:In this work we describe a phenomenon of accumulation of copper (Cu) in livers of a teleost fish commonly known as mullet,Mugil cephalus. High levels of Cu, up to 1936 μg/g wet weight were found. The high Cu levels seem not to be associated with environmental Cu contamination, since the fish were collected from widely separated regions with low Cu concentrations. Other fish species sharing the same environment did not show high levels of Cu. The accumulation of Cu in mullet was seen in liver and most of the hepatic Cu was located in the non‐cytosolic fraction. The intrahepatic distribution of Cu in mullet seems to depend on the total Cu content in the liver; as the total liver burden of Cu rose, Cu was increasingly recovered from the non‐cytosolic fraction. Metallothionein in hepatic cytosols from mullet containted the most Cu. However, the Cu concentration not bound to metallothionein rose when total cytosolic Cu increased; which show that metallothionein, particularly at higher Cu levels, is not the major hepatic Cu‐binding protein in cytosols of mullet. This report shows mullet as a very useful model to study the accumulation of Cu in the liver, which may lead to a better understanding of cellular mechanisms which control Cu homeostasis.
Life Prediction for Complex Structures
Authors: Forth S. C. , Annigeri B. S. , Keat W. D.
Published: September 2005

The surface integral method, an indirect boundary element method that represents a crack as a distribution of force dipoles, has been developed to model three-dimensional nonplanar crack growth in complex structures. The finite body was effectively modeled by superposition of stress influence functions for a half-space. As a result of this strategy, only the fracture has to be discretized. Crack propagation was modeled using the maximum circumferential stress theory to predict crack direction and the Forman fatigue equation, modified with an equivalent stress intensity solution for mixed-mode, to predict extension. Comparisons with benchmark solutions and field data verified the computational methodology and defined the limits of its applicability.
Application of Computational Fluid Dynamics Analysis for Rotating Machinery—Part II: Labyrinth Seal Analysis
Authors: Hirano Toshio , Guo Zenglin , Kirk R. Gordon
Published: September 2005

Labyrinth seals are used in various kinds of turbo machines to reduce internal leakage flow. The working fluid, or the gas passing through the rotor shaft labyrinth seals, often generates driving force components that may increase the unstable vibration of the rotor. It is important to know the accurate rotordynamic force components for predicting the instability of the rotor-bearing-seal system. The major goals of this research were to calculate the rotordynamic force of a labyrinth seals utilizing a commercial CFD program and to further compare those results to an existing bulk flow computer program currently used by major US machinery manufacturers. The labyrinth seals of a steam turbine and a compressor eye seal are taken as objects of analysis. For each case, a 3D model with eccentric rotor was solved to obtain the rotordynamic force components. The leakage flow and rotor dynamics force predicted by CFX TASCFlow are compared with the results of the existing bulk flow analysis program DYNLAB. The results show that the bulk flow program gives a pessimistic prediction of the destabilizing forces for the conditions under investigation. Further research work will be required to fully understand the complex leakage flows in turbo machinery.
Optimization of Wall Cooling in Gas Turbine Combustor Through Three-Dimensional Numerical Simulation
Authors: Gordon R. , Levy Y.
Published: September 2005

This paper is concerned with improving the prediction reliability of CFD modeling of gas turbine combustors. CFD modeling of gas turbine combustors has recently become an important tool in the combustor design process, which till now routinely used the old “cut and try” design practice. Improving the prediction capabilities and reliability of CFD methods will reduce the cycle time between idea and a working product. The paper presents a 3D numerical simulation of the BSE Ltd. YT-175 engine combustor, a small, annular, reversal flow type combustor. The entire flow field is modeled, from the compressor diffuser to turbine inlet. The model includes the fuel nozzle, the vaporizer solid walls, and liner solid walls with the dilution holes and cooling louvers. A periodic 36 deg sector of the combustor is modeled using a hybrid structured/unstructured multiblock grid. The time averaged Navier-Stokes (N-S) equations are solved, using the k-ε turbulence model and the combined time scale (COMTIME)/PPDF models for modeling the turbulent kinetic energy reaction rate. The vaporizer and liner walls’ temperature is predicted by the “conjugate heat transfer” methodology, based on simultaneous solution of the heat transfer equations for the vaporizer and liner walls, coupled with the N-S equations for the fluids. The calculated results for the mass flux passing through the vaporizer and various holes and slots of the liner walls, as well as the jet angle emerging from the liner dilution holes, are in very good agreement with experimental measurements. The predicted location of the liner wall hot spots agrees well with the position of deformations and cracks that occurred in the liner walls during test runs of the combustor. The CFD was used to modify the YT-175 combustion chamber to eliminate structural problems, caused by the liner walls overheating, that were observed during its development.
Multidimensional Predictions of In-Cylinder Turbulent Flows: Contribution to the Assessment of k-ε Turbulence Model Variants for Bowl-in-Piston Engines
Authors: Baratta Mirko , Catania Andrea E. , Spessa Ezio , Liu Rui L.
Published: September 2005

Multidimensional computational fluid dynamics (CFD) codes with reliable turbulence models are useful investigation and design tools for internal combustion engines, in-cylinder flow phenomena being critical to the combustion process and related emission sources. Although a variety of turbulence models has long been proposed, the assessment of even the most widely used k-ε model is still lacking, especially for bowl-in-piston engines. This paper provides a survey of k-ε turbulence model variants and their numerical implementation for in-cylinder flow analysis. Mean motion and turbulence quantities were simulated in the axisymmetric combustion chamber of a motored model engine featuring one centrally located valve and each of a flat-piston and cylindrical bowl-in-piston arrangements. A noncommercial CFD code developed by the authors was applied for calculation, using a finite-volume conservative implicit method and applying various order-of-accuracy numerical schemes. Simulation results are presented at the engine speed of 200 rpm throughout the whole engine cycle. These were obtained using three k-ε turbulence model versions, standard, renormalization group (RNG) and two scale, each of which focuses on one main engine flow feature, i.e., compressibility, anisotropy, and high unsteadiness, respectively. Modified boundary conditions with respect to conventional logarithmic wall functions were applied. Effects of equation-differencing scheme and computational-grid spacing effects on flow predictions were tested. The numerical results were compared to those of laser Doppler velocimetry measurements and the influence of the k-ε model variants on the flow-field features was examined during the induction stroke and around compression top dead center. For the flat-piston case, a comparison between the homemade and commercial STAR-CD® code results was also made.
Feasibility Study of an On-Board Natural Gas to Dimethyl Ether Reactor for Dimethyl Ether Preinjection and Enhanced Ignition
Authors: Horstman David , Abata Duane , Keith Jason , Oberto Leroy
Published: September 2005

Dual fuel (CI) engines provide an excellent means of maintaining high thermal efficiency and power while reducing emissions. This is particularly true in situations where the main CI fuel does not exhibit good autoignition characteristics, such as diesel engines operating on natural gas usually in stationary applications such as a pipeline installation. This paper explores the feasibility of chemically synthesizing DME from natural gas “on-board” and using it as an ignition source for a dual fuel engine. Conversion from diesel to dual fuel operation merits substantial benefits in PM emission reduction. Assuming a 5% pilot amount, a “once through” process has been modeled and a first law analysis (using practical isentropic efficiencies) demonstrates that this combined system can be operated with a reduction of between 5%–10% of the equivalent diesel efficiency. Significant quantities (∼30vol%) of hydrogen are introduced to the natural gas as a byproduct of the DME synthesis process. The corresponding increase in combustion efficiency must be validated by experiments to determine DME and H2 requirements for successful pilot ignition of the natural gas/H2 mixture.
An Analysis of Turbocharged Diesel Engine Dynamic Response Improvement by Electric Assisting Systems
Authors: Katrašnik Tomaž , Trenc Ferdinand , Medica Vladimir , Markič Stojan
Published: September 2005

It is well known that turbocharged diesel engines suffer from an inadequate response to sudden load increase, this being a consequence of the nature of the energy exchange between the engine and the turbocharger. The dynamic response of turbocharged diesel engines could be improved by electric assisting systems, either by direct energy supply with an integrated starter-generator-booster (ISG) mounted on the engine flywheel, or indirect energy supply with an electrically assisted turbocharger. A previously verified zero dimensional computer simulation method was used for the analysis of both types of electrical assistance. The credibility of the data presented is further assured by the experimentally determined characteristics of the electric motors used as input parameters of the simulation. The paper offers an analysis of the interaction between a turbocharged diesel engine operating under various load conditions and electric assisting systems, as well as the requirements for supporting electric motors suitable for the improvement of an engine’s dynamic response. It is evident that an electrically assisted turbocharger outperforms an integrated starter-generator-booster for vehicle application, however ISG is the preferred solution when instant power increase is demanded.
Analysis of Tangential-Against-Rotation Injection Lomakin
Bearings
Authors: Arghir Mihai , Hélène Mathieu , Frene Jean
Published: September 2005

This work presents a thin film flow model for analyzing the static and dynamic characteristics of centered, eccentric or misaligned tangential-against-rotation injection Lomakin bearings. The Lomakin bearing is a recent device intended for use in modern turbomachinery and having characteristics similar to hybrid bearings. It can be described as an ensemble of two opposing straight annular seals separated by a circumferential feeding groove. The fluid is supplied to the groove via orifice restrictors. Their tangential inclination generates an against-rotation circumferential flow in the groove that further penetrates into the thin film. This effect, known from annular seals as the prerotation speed, improves the dynamic characteristics of the bearing. A good description of the flow in the circumferential groove and the thin film is obtained from a full Navier–Stokes calculation of the centered bearing. The zero and first order analyses are then carried out by recognizing the crucial importance of taking into account the interaction between the flow in the thin film lands, the circumferential groove and the supply orifices. Due to the high Reynolds number regime, the land flow is governed by the two-dimensional thin film inertia equations (the “bulk flow” model). A one-dimensional circumferential flow dominated by inertia forces is assumed to take place in the groove and is described by an appropriate bulk flow equation. The flows in the supply orifices, the groove and the thin film lands are linked together by the same mass flow rate balance algorithm as used for hydrostatic and hybrid bearings analysis. The algorithm is extended to Lomakin bearings by considering the groove areas surrounding each orifice as a row of intercommunicating feeding pockets. This approach enables the analysis of centered, eccentric or misaligned Lomakin bearings. Comparisons with water-lubricated test results are used to validate the present model. For the zero eccentricity case a good agreement is obtained for the cross-coupled stiffness and for the whirl frequency ratio. A parametric study shows the variation of the bearing characteristics with increasing static eccentricity or misalignment.
Demonstration of a Reheat Combustor for Power Production With CO2 Sequestration
Authors: Chorpening Ben , Richards Geo. A. , Casleton Kent H. , Woike Mark , Willis Brian , Hoffman Larry
Published: September 2005

Concerns about climate change have encouraged significant interest in concepts for ultralow or “zero”-emissions power generation systems. In a concept proposed by Clean Energy Systems, Inc., nitrogen is removed from the combustion air and replaced with steam diluent. In this way, formation of nitrogen oxides is prevented, and the exhaust stream can be separated into concentrated CO2 and water streams. The concentrated CO2 stream could then serve as input to a CO2 sequestration process. In this study, experimental data are reported from a full-scale combustion test using steam as the diluent in oxy-fuel combustion. This combustor represents the “reheat” combustion system in a steam cycle that uses a high and low-pressure steam expansion. The reheat combustor serves to raise the temperature of the low-pressure steam turbine inlet, similar to the reheat stage of a conventional steam power cycle. Unlike a conventional steam cycle, the reheat enthalpy is actually generated by oxy-fuel combustion in the steam flow. This paper reports on the unique design aspects of this combustor, as well as initial emissions and operating performance.
Regulation of cyanobacterial CO2-concentrating mechanisms through transcriptional induction of high-affinity Ci-transport systems
Authors: Woodger Fiona J , Badger Murray R , Price G Dean
Published: September 2005

Approximately 50% of global CO2-based productivity is now attributed to the activity of phytoplankton, including ocean-dwelling cyanobacteria. In response to inherent restrictions on the rate of CO2 supply in the aquatic environment, cyanobacteria have evolved a very efficient means of capturing inorganic carbon (Ci), as either CO2 or HCO3. for photosynthetic carbon fixation. This capturing mechanism, known as a CO2-concentrating mechanism (CCM), involves the operation of active CO2 and HCO3 transporters and results in the concentration of CO2 around RuBisCO, in a unique microcompartment called the carboxysome. The CCM exhibits two basic physiological states: a constitutive, low-affinity state; and a high-affinity state, which is induced in response to Ci limitation. Many of the genetic components of the CCM, including genes encoding Ci transporters, have been identified. It is apparent that the expression of genes encoding the inducible, high-affinity Ci transporters is particularly sensitive to Ci availability, and we are now interested in defining how cyanobacterial cells sense and respond to Ci limitation at the transcriptional level. Current theories include direct sensing of external Ci; sensing of internal Ci-pool fluctuations; and detection of changes in photorespiratory intermediates, carbon metabolites, or redox potential. At present, there is no consensual view. We have investigated the physiological and transcriptional responses of CCM mutants and wildtype strains to pharmacological treatments and various light, O2, and Ci regimes. Our data suggest that perception of Ci limitation by a cyanobacterial cell is either directly or indirectly related to the size of the internal Ci pool within the cell, in an oxygen-dependent manner.Key words: CO2-concentrating mechanisms, CO2 sensing, Ci transporters, Synechococcus PCC7942.
Light is required for low-CO2-mediated induction of transcripts encoding components of the CO2-concentrating mechanism in the cyanobacterium Synechococcus elongatus: analysis by quantitative reverse transcription - polymerase chain reaction
Authors: McGinn Patrick J , Jones Meaghan J , Macdonald Angela B , Campbell Douglas A
Published: September 2005

Photosynthetic efficiency in cyanobacteria is improved under conditions of inorganic carbon (Ci) limitation by the induction of a CO2-concentrating mechanism (CCM) that elevates the CO2 concentration around the primary carboxylase ribulose-1,5-bisphosphate carboxylaseoxygenase (Rubisco) in the carboxysome. The molecular details of low-Ci sensing in relation to regulation of CCM induction in cyanobacteria are not presently known. We have applied a quantitative reverse transcription  polymerase chain reaction technique to monitor the abundance of key CCM-related transcripts in Synechococcus elongatus under a variety of experimental conditions with the aim of probing the conditions required for CCM induction. Despite preliminary evidence for strong induction of cmpA, sbtA, and chpY transcripts in the dark under low Ci in Synechococcus elongatus, subsequent experiments in which contaminating levels of room light during harvest were eliminated demonstrated that light is required for induction of these transcripts. However, the requirement for light for significant accumulation of CCM-related transcripts was very modest and well below the light level required to induce measurable net photosynthetic electron transport. Brief treatments with weak monochromatic light under low Ci were sufficient to cause significant accumulation of transcripts in Synechococcus elongatus relative to cells held in continuous darkness.Key words: CO2-concentrating mechanism, cyanobacteria, photosynthesis.
Proteomic analysis of the CO2-concentrating mechanism in the open-ocean cyanobacterium Synechococcus WH8102
Authors: Gonzales Arlene D , Light Yooli K , Zhang Zhaoduo , Iqbal Tahera , Lane Todd W , Martino Anthony
Published: September 2005

The open-ocean cyanobacterium Synechococcus WH8102 has recently been sequenced, making high-throughput mass spectrometry(MS)-based proteomics studies possible. Here, we used 1D and 2D gel electrophoresis, matrix-assisted laser desorptionionization  time-of-flight (MALDI-TOF) MS, and two-hybrid analysis to study the composition and protein interactions within the carboxysome, a protein-rich polyhedral body involved in the CO2-concentrating mechanism. We identified the Rubisco large and small subunits and CsoS1 and CsoS2 in the carboxysome-rich particulate fraction and thus conclude the proteins were solely associated with the carboxysome. We also determined that the carboxysome fraction contained numerous membrane-associated proteins, consistent with the presence of membrane contamination. Two-hybrid analysis indicated that CsoS2 and OrfA strongly interacted. They formed dimers and interacted with each other. To our knowledge, this is the first indication of OrfA being biochemically linked to the carboxysome. The ε-class carbonic anhydrase CsoS3 did not interact with other carboxysome components in a binary manner. CsoS3 may not interact, or it may only bind, in fully formed multiprotein complexes. Finally, growth rates and protein expression were unchanged between 100 and 750 µL·L1 CO2.Key words: proteomics, CO2-concentrating mechanism, carboxysome, cyanobacteria, Synechococcus.
Cyanobacterial carbonic anhydrases
Authors: So Anthony K-C , Espie George S
Published: September 2005

Carbonic anhydrases (CAs) are ubiquitous zinc metalloenzymes that catalyze the reversible dehydration of HCO3. These enzymes are encoded by at least five distinct, evolutionarily unrelated gene families, four of which have been found among the cyanobacteria examined to date. However, the distribution and expression of these cyanobacterial α-, β-, γ-, and ∈-CAs and their homologues among species have not yet been investigated in great detail. In this study, the number, distribution, and catalytic function of known and putative CAs and CA-like proteins from a variety of freshwater and marine cyanobacteria are examined.Key words: carbonic anhydrase, carboxysome, CO2-concentrating mechanism, cyanobacteria, Prochlorococcus, Synechococcus, Synechocystis.
Proteomic assessment of an established technique for carboxysome enrichment from Synechococcus PCC7942
Authors: Long Ben M , Price G Dean , Badger Murray R
Published: September 2005

Carboxysomes are protein-bound, polyhedral microbodies within cyanobacteria, containing the key enzyme for photosynthetic CO2 fixation, ribulose-1,5-bisphosphate carboxylaseoxygenase (Rubisco). Sequencing of cyanobacterial genomes has revealed that cyanobacteria possess one or other of two types of carboxysomes. Cyanobacteria containing form 1A Rubisco possess α-carboxysomes, while those with form 1B Rubisco possess β-carboxysomes. Given the central importance of carboxysomes in the CO2-concentrating mechanism of cyanobacteria, understanding the nature and composition of these structures is of considerable importance. In an effort to develop techniques for the characterization of the structure of β-carboxysomes, particularly the outer protein shell, we have undertaken a proteomic assessment of the PercollMg2+ carboxysome enrichment technique using the freshwater cyanobacterium Synechococcus sp. PCC7942. Both matrix-assisted laser desorptionionization  time of flight mass spectrometry (MALDI-TOF MS) and multidimensional protein identification technology (MuDPIT) methods were used to determine the protein content of a novel carboxysome-rich fraction. A total of 17 proteins were identified using MALDI-TOF MS from enriched carboxysome preparations, while 122 proteins were identified using MuDPIT analysis on the same material. The carboxysomal protein CcmM was identified by MALDI-TOF MS as two distinct proteins of 38 and 58 kDa. The only other carboxysomal proteins identified were the large and small subunits of Rubisco (RbcL and RbcS). Reasons for the lack of evidence for the expected full complement of carboxysomal proteins and future directions are discussed.Key words: CO2-concentrating mechanism, cyanobacteria, carboxysomes, proteomics.
The central body of the cyanelles of Cyanophora paradoxa: a eukaryotic carboxysome?
Authors: Burey S C , Fathi-Nejad S , Poroyko V , Steiner J M , Löffelhardt W , Bohnert H J
Published: September 2005

The cyanelles of the glaucocystophyte Cyanophora paradoxa combine two prokaryotic features not found in other phototrophic eukaryotes: a peptidoglycan wall and a putative carboxysome. Both of them would be indispensable when a inorganic carbon concentrating mechanism involving high accumulation of bicarbonate in the cyanelle stroma is assumed. Two approaches were used. (i) An expressed sequence tag library was generated allowing access to interesting genes and microarray technology. Hybridization of the microarrays to RNA from cells grown at high and low CO2 yielded 97 genes that were upregulated under CO2 stress whereas 87 genes were found to be downregulated. (ii) Cyanelle central bodies were isolated and protein components other than Rubisco were investigated by mass spectrometry. So far, mass spectrometric analysis of putative carboxysomal proteins yielded only sequences with no match in the databases. Rubisco activase could be shown via in vitro import and Western blotting to be copackaged with Rubisco in isolated purified central bodies. While our data support the presence of an inorganic carbon concentrating mechanism in cyanelles, they do not allow us to distinguish the microcompartment as a carboxysome or pyrenoid.Key words: Cyanophora paradoxa, cyanelles, carboxysome, Rubisco activase, carbon-concentrating mechanism, microarrays.
Growth, photosynthesis, and gene expression in Chlamydomonas over a range of CO2 concentrations and CO2/O2 ratios: CO2 regulates multiple acclimation states
Authors: Vance Peter , Spalding Martin H
Published: September 2005

Growth, photosynthesis, and induction of two low CO2-inducible genes of Chlamydomonas reinhardtii Dangeard strain CC125 were quantified in a range of physiologically relevant CO2 and O2 concentrations (5%0.005% CO2 and 20% or 2% O2) using airlift bioreactors to facilitate the simultaneous measurement of both growth and in situ photosynthetic rates. Within these CO2 concentration ranges, O2 concentrations (20% vs. 2%) had no discernable effect on growth, photosynthetic rate, or induction of the periplasmic carbonic anhydrase (Cah1) and glycolate dehydrogenase (Gdh) genes in wild-type C. reinhardtii. These results failed to support the hypothesis that the CO2/O2 ratio plays any role in signaling for the up-regulation of limiting CO2-induced genes and (or) of the CO2-concentrating mechanism (CCM). The mRNA abundance of the Cah1 and Gdh genes appeared to be regulated in concert, suggesting co-regulation by the same signaling pathway, which, because of a lack of an O2 effect, seems unlikely to involve photorespiration or a photorespiratory metabolite. Instead, it appeared that the CO2 concentration alone was responsible for regulation of limiting CO2 acclimation responses. Based on growth, photosynthesis, and gene expression characteristics, three distinct CO2-regulated physiological states were recognized within the studied parameters, a high CO2 (5%0.5%) state, a low CO2 (0.4%0.03%) state, and a very low CO2 (0.01%0.005%) state. Induction of Cah1 expression and Gdh up-regulation occurred at a CO2 concentration between 0.5% and 0.4% CO2, delineating the high from the low CO2 states. Photosynthetic characteristics also were distinct in the three CO2-regulated physiological states, e.g., the estimated K0.5(CO2) of the high CO2, low CO2, and very low CO2 states were 72, 10, and 0.9 µmol·L1 CO2, respectively. In addition to a greater photosynthetic CO2 affinity, the very low CO2 state could be distinguished from the low CO2 state by an increased cell-doubling time and a smaller cell size.Key words: algae, Chlamydomonas, CO2, gene expression, induction, photorespiration, photosynthesis.
The carbonic anhydrase gene families ofChlamydomonas reinhardtii
Authors: Mitra Mautusi , Mason Catherine B , Xiao Ying , Ynalvez Ruby A , Lato Scott M , Moroney James V
Published: September 2005

Carbonic anhydrases (CAs) are zinc-containing metalloenzymes that catalyze the reversible interconversion of CO2and HCO3. Aquatic photosynthetic organisms have evolved different forms of CO2-concentrating mechanisms to aid Rubisco in capturing CO2from the surrounding environment. One aspect of all CO2-concentrating mechanisms is the critical roles played by various specially localized extracellular and intracellular CAs. There are three evolutionarily unrelated CA families designated α-, β-, and γ-CA. In the green alga, Chlamydomonas reinhardtii Dangeard, eight CAs have now been identified, including three α-CAs and five β-CAs. In addition, C. reinhardtii has another CA-like gene, Glp1 that is similar to known γ-CAs. To characterize these different CA isoforms, some of the CA genes have been overexpressed to determine whether the proteins have CA activity and to generate antibodies for in vivo immunolocalization. The CA proteins Cah3, Cah6, and Cah8, and the γ-CA-like protein, Glp1, have been overexpressed. Cah3, Cah6, and Cah8 have CA activity, but Glp1 does not. At least two of these proteins, Cah3 and Cah6, are localized to the chloroplast. Using immunolocalization and sequence analyses, we have determined that Cah6 is located to the chloroplast stroma and confirmed that Cah3 is localized to the chloroplast thylakoid lumen. Activity assays show that Cah3 is 100 times more sensitive to sulfonamides than Cah6. We present a model on how these two chloroplast CAs might participate in the CO2-concentrating mechanism of C. reinhardtii. Key words: carbonic anhydrase, CO2-concentrating mechanism, Chlamydomonas, immunolocalization.
Inorganic carbon acquisition by the chrysophyte algaMallomonas papillosa
Authors: Bhatti Shabana , Colman Brian
Published: September 2005

Photosynthetic characteristics of the chrysophyte alga Mallomonas papillosa Harris et Bradley were investigated to determine whether this species has some form of CO2-concentrating mechanism. The effect of external pH on the photosynthetic oxygen evolution rate of air-grown cells demonstrated an optimum in the pH range 5.07.0. This species lacked external carbonic anhydrase, and the cells had no capacity for direct bicarbonate uptake and had a low affinity for dissolved inorganic carbon. Measurement of the fluxes of CO2and O2in photosynthesizing cells at pH 7.0, using mass spectrometry, displayed no rapid uptake but only a slow depletion of CO2from the medium upon illumination. Furthermore, CO2uptake and O2evolution by M. papillosa was greatly reduced by iodoacetamide, an inhibitor of CO2fixation. The overall internal pH of M. papillosa was determined by distribution of14C-benzoic acid over the pH range 5.56.0 and [2-14C]-5,5-dimethyloxazolidine-2,4-dione over the pH range 6.57.0 between the cells and medium. As the external pH was lowered from 7.0 to 5.5, there was a decrease in the internal pH of M. papillosa cells from 8.31 to 7.75. The ΔpH was great enough to allow the intracellular accumulation of inorganic carbon by the diffusive uptake of CO2.Key words: bicarbonate uptake, chrysophyte, CO2uptake, internal pH, Mallomonas papillosa.