bluuebunny/crossref_metadata_2025 huggingface dataset:
The Catholicism of Werther
Authors: Tantillo Astrida Orle
Published: August 2010

This article argues that Die Leiden des jungen Werthers contains embedded Catholic symbols that shed light on Goethe's critical stance toward his protagonist and Pietism. It first turns to Goethe's autobiography and letters to ascertain his position on Catholic sacraments (especially that of confession) and then to the novel itself to analyze its Catholic elements.
Die Herz‐Turbine: Rhythm and Urban Experience in the Poetry of Gerrit Engelke (1890–1918)
Authors: Cowan Michael
Published: August 2010

Although once celebrated as a representative of “workers' poetry” (Arbeiterdichtung), the expressionist poet Gerrit Engelke (1890–1918) has, with the exception of a few canonical poems, largely been forgotten today. But Engelke's poetry merits a rereading on account of its early and sustained engagement with industrialization. More specifically, it offers an insightful case study into the cross‐currents linking expressionist aesthetics and industrial science on account of the author's efforts to imagine urban modernity and—the role of poetry in the modern world— through the lens of rhythm. Exploring the connections between Engelke's lyric and modern discourses on rhythm (work science, vitalist philosophy, dance and film), I argue that Engelke saw poetic rhythm as a means of overcoming, via aesthetics, what Georg Simmel had identified as the growing chasm between subjective and objective culture in the industrial world.
The Politics and Media of Apostrophe in Hölderlin's Hyperion
Authors: Franzel Sean
Published: August 2010

This paper explores the medial and rhetorical implications of the trope of apostrophe in Friedrich Hölderlin's Hyperion. In examining two figural speeches in the novel that are rife with the address of absent addressees, I argue that Hölderlin engages with the medial documentation of the events of the French Revolution ubiquitous at the time while reflecting on the status of utopian community in Germany. Both the so‐called “nihilism letter” at the end of the first book and the infamous “Scheltrede” addressed to the German people probe the depths of apostrophe's potential to represent the breakdown, rather than establishment, of intersubjective and person‐world relations. An examination of these apostrophic scenes sheds light on the novel's reflections on the rhetorical structure and the mediality of political and literary language in an age of Revolution and in turn deepens our understanding of Hölderlin's innovative deployment of the epistolary novel.
Eliza Haywoods Geschichte des Fräuleins Elisabeth Thoughtless (1756): Frühe Selbsterkenntnis und Ehekritik in der englischen Übersetzungsliteratur
Authors: Damrau Peter
Published: August 2010

Die Tradition, Frauenerleben aus weiblicher Perspektive zum Mittelpunkt eines Romans zu machen, beginnt in Deutschland nicht mit Sophie La Roches Geschichte des Fräuleins von Sternheim (1771), sondern mit den Werken englischer Schriftstellerinnen, die bereits bedeutend früher in deutschen Übersetzungen erschienen und bisher von der Germanistik nicht beachtet worden sind. An Eliza Haywoods Geschichte des Fräuleins Elisabeth Thoughtless (1756) soll hier exemplarisch gezeigt werden, wie in Deutschland Mitte des 18. Jahrhunderts bereits eine Form der Literatur von Frauen erscheint, die die Entwicklung eines weiblichen Charakters zum Mittelpunkt hat. Obwohl der Übersetzer die in diesem Roman enthaltene Kritik an der patriarchalisch geführten Ehe und der Idealisierung der Frau durch eine bewusst gewählte Übersetzungsstrategie abschwächt, um der Leserschaft den für deutsche Verhältnisse zu radikalen Text angenehmer zu machen, ist dieser, von Lessing als das Werk eines Genies bewertete Roman ein Meilenstein in der Literatur von Frauen.
Der widerspenstige Signifikant: Herta Müllers collagierte Poetik desKönigs
Authors: Moyrer Monika
Published: August 2010

Mein Aufsatz setzt sich mit Herta Müllers vielschichtiger Figur des “Königs” auseinander. Er zeigt, wie der König des großväterlichen Schachspiels als Ur‐könig dient und sich zur politischen und poetischen Schlüsselmetapherentwickelt. Müllers Königagiert als ambivalenter Signifikant in verschiedenen Machtkonstellationen. Meine Analyse stützt sich auf historisch‐politische Diskurse, in denen die körperliche Gebrechlichkeit Königsfiguren zum Verhängnis wird. Ich ziehe Verbindungslinien zwischen der historischen Enthauptung und der Collagetechnik, die es Müller erlauben, an den König Hand anzulegen. Beweglichkeit, Köpfung und Verschiebung in andere räumliche Kontexte ermöglichen es ihr, die traumatisch‐subjektive Fixierung auf den König zu brechen. Wie im Schachspiel, schöpft die Schriftstellerin in der Collagedichtung die ihr zur Verfügung stehenden spielerischen Bewegungsräume aus und interveniert auf diese Weise in den Machtdiskurs.
Genomic fingerprinting and serotyping of Salmonella from Galápagos iguanas demonstrates island differences in strain diversity
Authors: Wheeler Emily , Cann Isaac K. O. , Mackie Roderick I.
Published: August 2010

Salmonella carriage patterns in wild and captive reptiles suggest that both geographical proximity and host ecological differences may determine bacterial diversity among reptile populations. In this study, we explore the relative importance of these factors on Salmonella diversity in free‐living Galápagos iguanas. We isolated Salmonella enterica from marine iguanas (Amblyrhynchus cristatus) and land iguanas (Conolophus subcristatus and C. pallidus) living on two islands (Plaza Sur and Santa Fe). We evaluated Salmonella population patterns using genomic fingerprints, sequence typing and serotyping. Rep‐PCR fingerprinting revealed significant grouping of isolates by iguana population. Island residence had the strongest effect on isolate similarity, but a smaller divergence among Salmonella isolates from different iguana ecotypes (land versus marine) was detected within each island. In contrast, sequence typing detected a marginal difference in isolate genotypes between islands. Sequence types corresponded strongly to serotype identity, with both islands hosting a unique serovar pool. Our findings suggest that both geographical location and host ecotype differences (either from within host strain selection or from differences in habitat use) contribute to Salmonella population patterns in the Galápagos Islands.
CLINICAL APPLICATIONS OF SERUM ENZYME DETERMINATIONS
Authors: Dunavant Michael L. , Rich L. J.
Published: August 2010

This study determined the normal enzyme levels in horses, cattle, and dogs for a group of 10 enzymes. The enzyme tests were then evaluated under clinical conditions, and case histories are presented to illustrate the useful applications of these tests.

Following clinical evaluations, the tests were grouped into profiles for the study of disease syndromes. Each profile contained the tests of greatest value in evaluating a specific organ or tissue. Sorbitol dehydrogenase (SDH) and glutamic dehydrogenase (GLDH) are enzymes found primarily in the liver and are combined with the less tissue specific glutamic oxalacetic transaminase (GOT) to monitor hepatocellular degeneration. Aldolase (ALD) and creatine phosphokinase (CPK) are enzymes found primarily in skeletal muscle. Elevations of ALD, CPK, and GOT can assist in the diagnosis of skeletal muscle degeneration. Not only are the newer enzyme tests relatively organ specific but also offer greater sensitivity than has previously been obtained.
CLINICAL OSMOMETRY IN VETERINARY MEDICINE
Authors: Tasker John B.
Published: August 2010

Although the concept of osmosis and osmotic pressure is one which is encountered repeatedly in the many disciplines within veterinary medicine, it is difficult to find a general discussion of the use of osmometry in clinical veterinary medicine. The following is an attempt to provide a summary of present knowledge in this area.
Foreign Languages and Sustainability: Addressing the Connections, Communities, and Comparisons Standards in Higher Education
Authors: Ter Horst Eleanor E. , Pearce Joshua M.
Published: August 2010

Abstract: This article describes an interdisciplinary collaboration that combined the study of German language with instruction in environmental issues (sustainable development). The project, involving both an independent study and a classroom unit, allowed students to make connections between disciplines, establish contact with German‐speaking communities outside the university, and make cultural and linguistic comparisons. By expanding the German‐language content on the Web site Appropedia.org, which is devoted to global sustainable development, students took an active role in learning by creating content that can be read and used by the global community of German speakers. This project provided a model for successful interdisciplinary instruction. The results of this study show that integrating environmental issues with foreign language study provides significant opportunities for students to increase their language proficiency, develop their understanding of concepts related to the environment, and become more involved in a global community through a virtual service learning project.
Constructivist Grammatical Learning: A Proposal for Advanced Grammatical Analysis for College Foreign Language Students
Authors: Mojica‐Díaz Clara C. , Sánchez‐López Lourdes
Published: August 2010

Abstract: The teaching of foreign language advanced grammar (AG) at the college level nowadays continues largely to focus on form, with little attention to its functions and meanings. The practice agrees with neither the Standards for Foreign Language Learning in the 21st Century (National Standards, 2006) nor the advances made in basic language teaching pertaining to the communicative purpose and context of language. Since both second language acquisition and pedagogical research demand more attention to contextual use, as well as the active participation of the student in the analysis of the forms, a revision of current practices becomes necessary. This article proposes the study of AG based on the use of unabridged authentic texts and the application of a Constructivist Grammatical Learning Approach.
Short‐Term Study Abroad: Predicting Changes in Oral Skills
Authors: Martinsen Rob A.
Published: August 2010

Abstract: Increasing numbers of students are opting for study abroad programs of 2 months or less while research on study abroad generally focuses on semester‐ or year‐long programs. This study quantitatively examines changes in students' spoken Spanish after 6 weeks in Argentina using native speaker ratings of student speech. The researcher then uses self‐report measures to determine which of the following variables predict improvements in speaking, pre‐program motivation and intercultural sensitivity, relationship with the host family, and interaction with native speakers. Results suggest that short‐term programs can benefit language skills, as the majority of students in this program demonstrated small yet highly significant improvements in spoken Spanish even though a percentage of students showed a decrease in their skills. Surprisingly, only pre‐program levels of cultural sensitivity predicted students' improvements in language skills, providing further evidence of the importance of culture in language learning.
Greatest lower bounds on the Ricci curvature of Fano manifolds
Authors: Székelyhidi Gábor
Published: August 2010

On a Fano manifoldMwe study the supremum of the possibletsuch that there is a Kähler metricω∈c1(M) with Ricci curvature bounded below byt. This is shown to be the same as the maximum existence time of Aubin’s continuity path for finding Kähler–Einstein metrics. We show that onP2blown up in one point this supremum is 6/7, and we give upper bounds for other manifolds.
Irreducible quotients ofA-hypergeometric systems
Authors: Saito Mutsumi
Published: August 2010

Gel’fand, Kapranov and Zelevinsky proved, using the theory of perverse sheaves, that in the Cohen–Macaulay case anA-hypergeometric system is irreducible if its parameter vector is non-resonant. In this paper we prove, using the theory of the ring of differential operators on an affine toric variety, that in general anA-hypergeometric system is irreducible if and only if its parameter vector is non-resonant. In the course of the proof, we determine the irreducible quotients of anA-hypergeometric system.
A Color Image Processing System for Transient Liquid Crystal Heat Transfer Experiments
Authors: Wang Z. , Ireland P. T. , Jones T. V. , Davenport R.
Published: August 2010

A color image processing system for liquid crystal heat transfer experiment has been developed. The system is capable of digitizing and processing the complete liquid crystal surface color (hue) change history in a transient test and, together with a calibration, can give the complete history of surface temperature over a full surface. Two methods for automatically processing the hue history to give heat transfer coefficient distributions are presented. Both methods raise the accuracy of the transient technique above other approaches by using the redundancy inherent in the multiple surface temperature measurements. The first regression approach applied to the determination of both h and Tgas is reported. The uncertainty in all measurements has been quantified and examples of applications of both techniques given.
Studies on Wake-Affected Heat Transfer Around the Circular Leading Edge of Blunt Body
Authors: Funazaki K.
Published: August 2010

Detailed measurements are performed about time-averaged heat transfer distributions around the leading edge of a blunt body, which is affected by incoming periodic wakes from the upstream moving bars. The blunt body is a test model of a front portion of a turbine blade in gas turbines and consists of a semicircular cylindrical leading edge and a flat plate afterbody. A wide range of the steady and unsteady flow conditions are adopted as for the Reynolds number based on the diameter of the leading edge and the bar-passing Strouhal number. The measured heat transfer distributions indicate that the wakes passing over the leading edge cause a significant increase in heat transfer before the separation and the higher Strouhal number results in higher heat transfer. From this experiment, a correlation for the heat transfer enhancement around the leading edge due to the periodic wakes is deduced as a function of the Stanton number and it is reviewed by comparison with the other experimental works.
Design of a Low Aspect Ratio Transonic Compressor Stage Using CFD Techniques
Authors: Sanger N. L.
Published: August 2010

A transonic compressor stage has been designed for the Naval Postgraduate School Turbopropulsion Laboratory. The design relied heavily on CFD techniques while minimizing conventional empirical design methods. The low aspect ratio (1.2) rotor has been designed for a specific head ratio of 0.25 and a tip relative inlet Mach number of 1.3. Overall stage pressure ratio is 1.56. The rotor was designed using an Euler code augmented by a distributed body force model to account for viscous effects. This provided a relatively quick-running design tool, and was used for both rotor and stator calculations. The initial stator sections were sized using a compressible, cascade panel code. In addition to being used as a case study for teaching purposes, the compressor stage will be used as a research stage. Detailed measurements, including nonintrusive LDV, will be compared with the design computations, and with the results of other CFD codes, as a means of assessing and improving the computational codes as design tools.
Development of Two-Dimensional Wakes Within Curved Channels: Theoretical Framework and Experimental Investigation
Authors: Schobeiri M. T. , John J. , Pappu K.
Published: August 2010

The development of a wake flow downstream of a cylindrical rod within a curved channel under zero streamwise pressure gradient is theoretically and experimentally investigated. The measured asymmetric wake quantities such as the mean velocity and turbulent fluctuations in longitudinal and lateral directions as well as the turbulent shear stress are transformed from the probe coordinate system into the curvilinear wake eigen-coordinate system. For the transformed non-dimensionalized velocity defect and the turbulent quantities, affine profiles are observed throughout the flow regime. Based on these observations and using the transformed equations of motion and continuity, a theoretical frame work is established that generally describes the two-dimensional curvilinear wake flow. The theory also describes the straight wake as a special case, for which the curvature radius approaches infinity. The comparison of the theory with the experimental data pertaining to the curvilinear and straight wakes demonstrate the general validity of the theory.
Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter: Part II—Unsteady Measurements
Authors: Brun K. , Flack R. D. , Gruver J. K.
Published: August 2010

The unsteady velocity field found in the pump of an automotive torque converter was measured using laser velocimetry. Velocities in the inlet, mid-, and exit planes of the pump were investigated at two significantly different operating conditions: turbine/pump rotational speed ratios of 0.065 and 0.800. A data organization method was developed to visualize the three-dimensional, periodic unsteady velocity field in the rotating frame. For this method, the acquired data are assumed to be periodic at synchronous and blade interaction frequencies. Two shaft encoders were employed to obtain the instantaneous angular position of the torque converter pump and turbine at the instant of laser velocimeter data acquisition. By proper “registration” of the data, visualizing the transient interaction effects between the stator and the pump, and between the pump and the turbine, was possible. Results showed strong cyclic velocity fluctuations in the pump inlet plane as a function of the relative stator-pump position. Typical percent periodic fluctuations in the through flow velocity were 70 percent of the average throughflow velocity. The upstream propagation influence of the turbine on the pump exit plane flow field was seen to be smaller. Percent periodic fluctuations of the throughflow velocity were typically 30 percent. The effect of the stator and turbine on the midplane flow field was seen to be negligible. The incidence angle at the pump inlet fluctuated by 27 and 14 deg for the 0.065 and 0.800 speed ratios, respectively. Typical slip factors at the exit were 0.965 and fluctuated by less than 1 percent.
The Influence of Cure Time Restrictions on Minimum-Weight Design of Double-Layer SMC Panels
Authors: Barone M. R. , Caulk D. A. , Chang D. C.
Published: August 2010

In this paper, minimum-weight design of double-layer panels made from sheet molding compound is related to cure time—a critical indicator of manufacturing cost. This is done by incorporating cure time restrictions in the optimization analysis. Depending on the design constraints imposed on the panel, the least-weight design can require cure times which are unacceptably long for economical high volume production. Nevertheless, we show that cure time can be brought within acceptable bounds by design changes that incur only modest increases in weight.
A Fracture Surface Rotation Mechanism for Fatigue Tested 2219-T87 Aluminum Sheet
Authors: Pittinato G. F.
Published: August 2010

Fatigue crack propagation tests were conducted on 2219-T87 aluminum sheet to identify the factors that control the rate of fracture surface rotation. Center-cracked, axial loaded specimens were tested in air at room temperature using tension-tension loading. The log (da/dn) versus (ΔK) curve contained an inflection point that was associated with the flat to slant fracture transition. The size and shape of the plastic zone at the crack tip were determined as a function of the half-crack length by using optical interferometry. It was found that the rate of fracture surface rotation was controlled by the changing size of the crack tip plastic zone. It is proposed that fracture surface rotation in this material occurs by a process of crack movement within active slip zones. A discussion is given on the deformation mechanisms associated with fatigue fracture surface rotation.
Producing a Tough, High Strength Cast Steel Free of Temper Embrittlement
Authors: Floreen S.
Published: August 2010

Temper embrittlement of a cast 3Ni-3Cr steel was produced by small amounts of either P or Mn in samples tempered at 650°C and air cooled. Auger spectroscopy examinations showed P embrittlement was produced by cosegregation of P, Ni, and Cr. Embrittlement by Mn appeared to be caused by Mn and S segregation. In coarse grained materials fractures were intergranular. In fine grained material, both intergranular and brittle transgranular fractures were observed, and Auger mapping showed impurity enrichment on transgranular fracture surfaces. Segregation and fracture on martensite packet boundaries is suggested as the origin of the transgranular fracture. Changing the tempering temperature and adding a half percent Mo solved the embrittlement problem. Water quenching was not required. A 150 mm thick casting of the new composition showed good tolerance for P and Mn, a yield strength of 500 MPa, and good toughness down to −80°C.
A Study of Multiple Hole Extrusion
Authors: Bagchi Amit , Lenard John G.
Published: August 2010

Two mathematical models proposed by Avitzur and valid for axially symmetrical square extrusion are tested for their ability to predict the maximum power required in single as well as multiple hole extrusion. Comparison to experimental results obtained using plumber’s lead shows good correlation. The most significant parameter is shown to be the total area reduction. The velocity field in multiple hole extrusion—which by necessity must be nonaxially symmetrical—appears not to affect the power required for extrusion.
Application of J-Integral to High-Temperature Crack Propagation: Part II—Fatigue Crack Propagation
Authors: Taira Shuji , Ohtani Ryuichi , Komatsu Tomio
Published: August 2010

On the basis of the successful results of our previous study on a J-integral approach to the creep crack propagation of steels, the applicability of the creep J-integral to the time dependent fatigue crack propagation in creep range was studied. A satisfactory correlation was obtained between crack propagation rate and creep J-integral, and the same correlation was found in creep crack propagation under constant load as well as two-step loading. It was also found that the cycle dependent fatigue crack propagation rate could be successfully correlated by the cyclic J-integral. The high crack propagation rate in large scale yielding fatigue may be in agreement with the straight line extrapolation on log-log plots of the linear elastic fatigue crack propagation rate versus cyclic J-integral data.
Fatigue Crack Growth in 2-1/4-Cr-1Mo Steel Exposed to Hydrogen Containing Gases
Authors: Brazill R. , Simmons G. W. , Wei R. P.
Published: August 2010

Steels used in coal gasification vessels and piping (externals) can be exposed to mixtures of hydrogen, water vapor (steam), hydrogen sulfide, methane, carbon monoxide, carbon dioxide, and other gases at temperatures and pressures up to 600°K and 10 MPa. Such mixtures, under certain operating conditions, can either enhance or inhibit crack growth in these steels. As a part of a program to identify thermodynamic conditions for this enhancement or inhibition, fatigue crack growth experiments have been carried out on a 2-1/4Cr-1 Mo (ASTM A542, Class 2) steel in hydrogen, water vapor, and hydrogen sulfide at low pressures (below 133 kPa). The results indicate considerable enhancement of fatigue crack growth by some of these environments and also indicate that the apparent immunity of this material to stress corrosion cracking does not imply the same immunity to corrosion fatigue. The results will be discussed in terms of the influences of temperature, gas pressure and loading variables, and will be interpreted in terms of chemical reaction kinetics.
The Fatigue-Crack Propagation Response of Two Nickel-Base Alloys in a Liquid Sodium Environment
Authors: Mills W. J. , James L. A.
Published: August 2010

The elevated temperature fatigue-crack propagation response of Inconel 600 and Inconel 718 was characterized within a linear-elastic fracture mechanics framework in air and low-oxygen liquid sodium environments. The crack growth rates of both nickel-base alloys tested in liquid sodium were found to be considerably lower than those obtained in air. This enhanced fatigue resistance in sodium was attributed to the very low oxygen content in the inert sodium environment. Electron fractographic examination of the Inconel 600 and Inconel 718 fatigue fracture surfaces revealed that operative crack growth mechanisms were dependent on the prevailing stress intensity level. Under low growth rate conditions, Inconel 600 and Inconel 718 fracture surfaces exhibited a faceted, crystollographic morphology in both air and sodium environments. In the higher growth rate regime, fatigue striations were observed; however, striations formed in sodium were rather ill-defined. These indistinct striations were attributed to the absence of oxygen in the liquid sodium environment. Striation spacing measurements were found to be in excellent agreement with macroscopic growth rates in both environments.
A Tabular Summary of Some Experiments in Dynamic Plasticity
Authors: Holzer A. J.
Published: August 2010

A tabular summary of some experiments in dynamic plasticity is presented. The experimental work is divided into three categories according to the type of testing machine used. The results of investigations using the cam-plastometer, experimental drop forges, and split Hopkinson pressure bars are presented. In addition, a number of other methods for obtaining dynamic mechanical properties are discussed.
Mechanical Behavior of Metals in Dynamic Compression
Authors: Holzer A. J. , Brown R. H.
Published: August 2010

A technique for the measurement of force and displacement data in metal processing at high rates of deformation is described briefly. Forces are determined by fast Fourier transformation of the signal from a quartz load cell and correction in the frequency domain for dynamic response of the load cell. Displacement is measured by a high frequency response fiber-optic transducer. The force and displacement signals are processed by an on-line computer which enables stress, strain, strain-rate, and other parameters to be determined and plotted rapidly. Results from continuous dynamic compression tests are presented in the form of computer generated stress-strain and stress-strain rate curves for two steels. In the strain rate range 10−3 s−1 to 102 s−1 an hydraulic testing machine is used. In the range 102 s−1 to 104 s−1 a drop forge is used. A discussion of the effects of specimen geometry in compression testing is included.
Plastic Flow of Mild Steel Under Proportional and Non-Proportional Straining at a Controlled Rate
Authors: Meguid S. A. , Malvern L. E. , Campbell J. D.
Published: August 2010

In the present investigation, thin tubular specimens of annealed mild steel (En8) were tested under combined straining, using a newly developed tension-torsion, closed-loop, servo-controlled, electro-hydraulic testing machine. Two types of straining program were used, proportional straining at constant strain rate and nonproportional straining in which the specimen was loaded to yield in pure torsion and then extended with the twist held constant. The resulting load and torque components were continuously recorded during each test, as functions of time. A remarkable feature of the second type of test is that it was possible to obtain almost the whole positive quadrant of the initial yield locus of this material from a single test, since the load-torque trajectory followed closely the yield locus. Both proportional and nonproportional straining paths gave results in good agreement with the von Mises yield condition. The work included two theoretical analyses of the present problem, one using Perzyna’s constitutive laws for rate-sensitive but nonworkhardening material and the other using a rate-independent theory. Comparison with the experimental results of the nonproportional straining program indicates that the time history of the neutral loading path was reasonably well matched by the prediction of both the rate-dependent and rate-independent theories. Some preliminary experimental investigations of the hardening behavior in the proportional paths are also reported.
On the frequency characteristic of inductor in the filter of Hall thrusters
Authors: Liqiu Wei , Zhongxi Ning , Peng E. , Daren Yu
Published: August 2010

It was found that low frequency discharge current oscillation of two inductors with the same nominal value is extremely different. To decide the general characteristic of thruster inductors, relationship between the frequency characteristic of inductors and low frequency oscillation is studied in experiments at the same operation conditions. Experimental results indicate that the differences of low frequency discharge current oscillation were caused by the different frequency characteristic of inductor. As the corner frequency of inductors increases, the discharge current low frequency oscillation declines at first and then slightly turns up after a certain frequency. Through analysis from the perspective of control system, advantageous frequency characteristics of thruster inductors in filter are suggested.
Photoyield recovery of Cs+NF3 activated negative electron affinity GaAs photoemitters without additional alkali deposition
Authors: Mulhollan G. A. , Bierman J. C.
Published: August 2010

A method by which negative electron affinity GaAs photocathodes can be made to recover their photoyield following decay is reported. The source of decay can be either an oxidizer in the background gas or gas introduced through deliberate dosing. Conventional methods employ the use of the alkali Cs as the photoyield recovery agent. This work describes an alkali application-free method, similar to electron stimulated desorption, for photoyield recovery.
Verge and Foliot Clock Escapement: A Simple Dynamical System
Authors: Denny Mark
Published: August 2010

The earliest mechanical clocks appeared in Europe in the 13th century. From about 1250 CE to 1670 CE, these simple clocks consisted of a weight suspended from a rope or chain that was wrapped around a horizontal axle. To tell time, the weight must fall with a slow uniform speed, but, under the action of gravity alone, such a suspended weight would accelerate. To prevent this acceleration, an escapement mechanism was required. The best such escapement mechanism was called the verge and foliot escapement, and it was so successful that it lasted until about 1800 CE. These simple weight-driven clocks with verge and foliot escapements were accurate enough to mark the hours but not minutes or seconds. From 1670, significant improvements were made (principally by introducing pendulums and the newly invented anchor escapement) that justified the introduction of hands to mark minutes, and then seconds. By the end of the era of mechanical clocks, in the first half of the 20th century, these much-studied and much-refined machines were accurate to a millisecond a day.1
A visual demo of the Doppler effect
Authors: Papacosta Pangratios
Published: August 2010

Most physics teachers are familiar with the standard classroom demonstration of the Doppler effect. We invite students to explain the periodic variation of the pitch produced when we swirl a sounding buzzer over our heads. Students are quick to connect this phenomenon to everyday life experiences such as listening to the sound of the siren of a fast-approaching police car or the bell of an approaching train. In addition to these aural experiences, our understanding of the Doppler effect can be strengthened with a useful visual metaphor.
Highs and lows
Authors: Riendeau Diane
Published: August 2010

Special thanks to Dean Baird, Rio Americano HS, Carmichael, CA; Alicia Akers, Deerfield High School, Deerfield, IL; Mark Moverman, Lab School of Washington, Washington, DC.
Enhancing learning through scientific mini-debates
Authors: Slater Timothy F.
Published: August 2010

Can your students “talk science” as a result of your instruction? Science education reformers argue that successful approaches to students learning science must feature experiences that allow students to “know, use, and interpret scientific explanations of the natural world,” to “generate and evaluate scientific evidence and explanations,” and to “participate productively in scientific practices and discourse.”1 Although one can readily agree that these are important characteristics of science education, finding ways to purposefully and frequently implement such elements is challenging indeed. Assigning numerical problems from the back of a physics or astronomy textbook seems to fall short. Similarly, tasking students to complete hands-on laboratory exercises verifying concepts presented in class appears to be insufficient. Driver and her colleagues argue that most science education learning environments do not provide sufficient opportunities for students to construct and respond to scientific arguments.2 Additionally, Osborn found that students do not naturally develop the skills needed for scientific discourse unless the skills are intentionally taught.3 So, how might one infuse the learning of science with opportunities for students to practice “talking science”?
Arginine: Master and Commander in Innate Immune Responses
Authors: Morris Sidney M.
Published: August 2010

In addition to acting as an enzyme substrate, arginine functions as a regulatory molecule in immune cells.
In Vitro
and
In Vivo
Efficacy of Florfenicol for Treatment of
Francisella asiatica
Infection in Tilapia
Authors: Soto Esteban , Endris Richard G. , Hawke John P.
Published: August 2010

Francisella asiatica
is a recently described, Gram-negative, facultative intracellular fish pathogen, known to be the causative agent of francisellosis in warm-water fish. Francisellosis outbreaks have increased in frequency among commercial aquaculture operations and have caused severe economic losses in every case reported. The lack of effective treatments for piscine francisellosis led us to investigate the potential efficacy of florfenicol for inhibition of
F. asiatica in vitro
and as an oral therapeutic agent
in vivo
. The MIC of florfenicol for
F. asiatica
, as determined by the broth dilution method, was 2 μg/ml, which indicates its potential efficacy as a therapeutic agent for treatment of francisellosis. The intracellular susceptibility of the bacterium to florfenicol in tilapia head kidney-derived macrophages (THKDM) was also investigated. Addition of florfenicol to the medium at 10 μg/ml was sufficient to significantly reduce bacterial loads in the THKDM
in vitro
. Cytotoxicity assays done in infected THKDM also demonstrated drug efficacy
in vivo
, as determined by lactate dehydrogenase (LDH) release. Levels of LDH released from infected THKDM were significantly lower in macrophages treated with florfenicol (
P
< 0.001) than in untreated cells. In medicated-feed trials, fish were fed 15 mg of florfenicol/kg of fish body weight for 10 days, and the feeding was initiated at either 1, 3, or 6 days postchallenge. Immersion challenges resulted in 30% mean percent survival in nontreated fish, and fish receiving medicated feed administered at 1 and 3 days postinfection showed higher mean percent survival (100% and 86.7%, respectively). A significant decrease (
P
< 0.001) in bacterial numbers (number of CFU/g of spleen tissue) was observed in treated groups compared to nontreated infected fish at both 1 and 3 days postchallenge. There were no differences in bacterial burden in the spleens between fish treated 6 days postchallenge and untreated controls. In conclusion, if florfenicol is administered during early stages of infection, it has the potential for effectively treating piscine francisellosis, including the capacity for intracellular penetration and bacterial clearance.
Efficacy and Safety of Intravenous Peramivir for Treatment of Seasonal Influenza Virus Infection
Authors: Kohno Shigeru , Kida Hiroshi , Mizuguchi Masashi , Shimada Jingoro
Published: August 2010

Peramivir, a sialic acid analogue, is a selective inhibitor of neuraminidases produced by influenza A and B viruses. We evaluated the efficacy and safety of a single intravenous dose of peramivir in outpatients with uncomplicated seasonal influenza virus infection. A total of 300 previously healthy adult subjects aged 20 to 64 years with a positive influenza virus rapid antigen test were recruited within 48 h of the onset of influenza symptoms and randomized to three groups: single intravenous infusion of either 300 mg peramivir per kg of body weight, 600 mg peramivir, or matching placebo on study day 1. Influenza symptoms and body temperature were self-assessed for 14 days. Nasal and pharyngeal swabs were collected to determine the viral titer. The primary endpoint was the time to alleviation of symptoms. Of the 300 subjects, 296 were included in the intent-to-treat infected population (300 mg peramivir,n= 99; 600 mg peramivir,n= 97; and placebo,n= 100). Peramivir significantly reduced the time to alleviation of symptoms at both 300 mg (hazard ratio, 0.681) and 600 mg (hazard ratio, 0.666) compared with placebo (adjustedPvalue, 0.0092 for both comparisons). No serious adverse events were reported. Peramivir was well tolerated, and its adverse-event profile was similar to that of placebo. A single intravenous dose of peramivir is effective and well tolerated in subjects with uncomplicated seasonal influenza virus infection.
Emergence and Molecular Characterization of Extensively Drug-Resistant
Mycobacterium tuberculosis
Clinical Isolates from the Delhi Region in India
Authors: Khanna Alka , Raj V. Samuel , Tarai Bansidhar , Sood Ruchi , Pareek Pawan Kumar , Upadhyay Dilip J. , Sharma Pawan , Rattan Ashok , Saini Kulvinder Singh , Singh Harpal
Published: August 2010

We screened 194
Mycobacterium tuberculosis
strains isolated from tuberculosis (TB) patients in Delhi and neighboring regions in India to identify the prevalence of extensive drug resistance (XDR) in clinical isolates. Among these, 104 isolates were found to be multidrug resistant (MDR), and 6 were identified as XDR isolates, which was later confirmed by antimicrobial susceptibility testing against the respective drug screening panel. Genotyping was carried out by amplifying and sequencing the following genes:
rpoB
(rifampin),
katG
(isoniazid),
gyrA
(fluoroquinolones), and
rrs
(amikacin, kanamycin, and capreomycin). Our analyses indicated that mutations at the hot spots of these genes were positively correlated with drug resistance in clinical isolates. The key mutation observed for
rpoB
was in the codon for amino acid position 531 (S531L), and other mutations were seen in the hot spot, including those encoding Q510P, L511H, D516V, and H526Y mutations. We identified S315T and R463L substitutions encoded in the
katG
locus. An S95T substitution encoded in the
gyrA
locus was the most common mutation observed in fluoroquinolone-resistant isolates. In addition, we saw D94G and D94N mutations encoded in the QRDR region. The 16S rRNA (
rrs
) gene encoded mainly the A1401G mutation and an additional mutation, G1484T, resulting in ribosomal modifications. Taken together, the data in this report clearly establish the presence of phenotypically distinct XDR strains in India by molecular profiling and further identify specific mutational hot spots within key genes of XDR-TB strains.
CD28 Exerts Protective and Detrimental Effects in a Pulmonary Model of Paracoccidioidomycosis
Authors: Felonato Maíra , Pina Adriana , Bernardino Simone , Loures Flávio V. , de Araujo Eliseu Frank , Calich Vera L. G.
Published: August 2010

T-cell immunity has been claimed as the main immunoprotective mechanism againstParacoccidioides brasiliensisinfection, the most important fungal infection in Latin America. As the initial events that control T-cell activation in paracoccidioidomycosis (PCM) are not well established, we decided to investigate the role of CD28, an important costimulatory molecule for the activation of effector and regulatory T cells, in the immunity against this pulmonary pathogen. Using CD28-deficient (CD28−/−) and normal wild-type (WT) C57BL/6 mice, we were able to demonstrate that CD28 costimulation determines in pulmonary paracoccidioidomycosis an early immunoprotection but a late deleterious effect associated with impaired immunity and uncontrolled fungal growth. Up to week 10 postinfection, CD28−/−mice presented increased pulmonary and hepatic fungal loads allied with diminished production of antibodies and pro- and anti-inflammatory cytokines besides impaired activation and migration of effector and regulatory T (Treg) cells to the lungs. Unexpectedly, CD28-sufficient mice progressively lost the control of fungal growth, resulting in an increased mortality associated with persistent presence of Treg cells, deactivation of inflammatory macrophages and T cells, prevalent presence of anti-inflammatory cytokines, elevated fungal burdens, and extensive hepatic lesions. As a whole, our findings suggest that CD28 is required for the early protective T-cell responses toP. brasiliensisinfection, but it also induces the expansion of regulatory circuits that lately impair adaptive immunity, allowing uncontrolled fungal growth and overwhelming infection, which leads to precocious mortality of mice.
Interleukin-4 Regulates the Expression of CD209 and Subsequent Uptake ofMycobacterium lepraeby Schwann Cells in Human Leprosy
Authors: Teles Rosane M. B. , Krutzik Stephan R. , Ochoa Maria T. , Oliveira Rosane B. , Sarno Euzenir N. , Modlin Robert L.
Published: August 2010

The ability of microbial pathogens to target specific cell types is a key aspect of the pathogenesis of infectious disease.Mycobacterium leprae, by infecting Schwann cells, contributes to nerve injury in patients with leprosy. Here, we investigated mechanisms of host-pathogen interaction in the peripheral nerve lesions of leprosy. We found that the expression of the C-type lectin, CD209, known to be expressed on tissue macrophages and to mediate the uptake ofM. leprae, was present on Schwann cells, colocalizing with the Schwann cell marker, CNPase (2′,3′-cyclic nucleotide 3′-phosphodiesterase), along with theM. lepraeantigen PGL-1 in the peripheral nerve biopsy specimens.In vitro, human CD209-positive Schwann cells, both from primary cultures and a long-term line, have a higher binding ofM. lepraecompared to CD209-negative Schwann cells. Interleukin-4, known to be expressed in skin lesions from multibacillary patients, increased CD209 expression on human Schwann cells and subsequent Schwann cell binding toM. leprae, whereas Th1 cytokines did not induce CD209 expression on these cells. Therefore, the regulated expression of CD209 represents a common mechanism by which Schwann cells and macrophages bind and take upM. leprae, contributing to the pathogenesis of leprosy.
RssAB-FlhDC-ShlBA as a Major Pathogenesis Pathway in
Serratia marcescens
Authors: Lin Chuan-Sheng , Horng Jim-Tong , Yang Chun-Hung , Tsai Yu-Huan , Su Lin-Hui , Wei Chia-Fong , Chen Chang-Chieh , Hsieh Shang-Chen , Lu Chia-Chen , Lai Hsin-Chih
Published: August 2010

Serratia marcescens
has long been recognized as an important opportunistic pathogen, but the underlying pathogenesis mechanism is not completely clear. Here, we report a key pathogenesis pathway in
S. marcescens
comprising the RssAB two-component system and its downstream elements, FlhDC and the dominant virulence factor hemolysin ShlBA. Expression of
shlBA
is under the positive control of FlhDC, which is repressed by RssAB signaling. At 37°C, functional RssAB inhibits swarming, represses hemolysin production, and promotes
S. marcescens
biofilm formation. In comparison, when
rssBA
is deleted,
S. marcescens
displays aberrant multicellularity favoring motile swarming with unbridled hemolysin production. Cellular and animal infection models further demonstrate that loss of
rssBA
transforms this opportunistic pathogen into hypervirulent phenotypes, leading to extensive inflammatory responses coupled with destructive and systemic infection. Hemolysin production is essential in this context. Collectively, a major virulence regulatory pathway is identified in
S. marcescens
.
Vitamin B
6
Is Required for Full Motility and Virulence in
Helicobacter pylori
Authors: Grubman Alexandra , Phillips Alexandra , Thibonnier Marie , Kaparakis-Liaskos Maria , Johnson Chad , Thiberge Jean-Michel , Radcliff Fiona J. , Ecobichon Chantal , Labigne Agnès , de Reuse Hilde , Mendz George L. , Ferrero Richard L.
Published: August 2010

Despite recent advances in our understanding of how
Helicobacter pylori
causes disease, the factors that allow this pathogen to persist in the stomach have not yet been fully characterized. To identify new virulence factors in
H. pylori
, we generated low-infectivity variants of a mouse-colonizing
H. pylori
strain using the classical technique of
in vitro
attenuation. The resulting variants and their highly infectious progenitor bacteria were then analyzed by global gene expression profiling. The gene expression levels of five open reading frames (ORFs) were significantly reduced in low-infectivity variants, with the most significant changes observed for ORFs HP1583 and HP1582. These ORFs were annotated as encoding homologs of the
Escherichia coli
vitamin B
6
biosynthesis enzymes PdxA and PdxJ. Functional complementation studies with
E. coli
confirmed
H. pylori
PdxA and PdxJ to be
bona fide
homologs of vitamin B
6
biosynthesis enzymes. Importantly,
H. pylori
PdxA was required for optimal growth
in vitro
and was shown to be essential for chronic colonization in mice. In addition to having a well-known metabolic role, vitamin B
6
is necessary for the synthesis of glycosylated flagella and for flagellum-based motility in
H. pylori
. Thus, for the first time, we identify vitamin B
6
biosynthesis enzymes as novel virulence factors in bacteria. Interestingly,
pdxA
and
pdxJ
orthologs are present in a number of human pathogens, but not in mammalian cells. We therefore propose that PdxA/J enzymes may represent ideal candidates for therapeutic targets against bacterial pathogens.

IMPORTANCE
Approximately half of the world’s population is infected with
H. pylori
, yet how
H. pylori
bacteria establish chronic infections in human hosts remains elusive. From gene array studies, we identified two genes as representing potentially novel colonization factors for
H. pylori
. These genes encoded enzymes involved in the synthesis of vitamin B
6
, an important molecule for many metabolic reactions in living organisms. Little is currently known regarding vitamin B
6
biosynthesis in human pathogens. We showed that mutant
H. pylori
bacteria lacking an enzyme involved in
de novo
vitamin B
6
biosynthesis, PdxA, were unable to synthesize motility appendages (flagella) and were unable to establish chronic colonization in mice. Thus, this work identifies vitamin B
6
biosynthesis enzymes as novel virulence factors for bacterial pathogens. Interestingly, a number of human pathogens, but not their mammalian hosts, possess these genes, which suggests that Pdx enzymes may represent ideal candidates for new therapeutic targets.