bluuebunny/crossref_metadata_2025 huggingface dataset:
Love's Usury, Poet's Debt: Borrowing and Mimesis in Shakespeare's Sonnets
Authors: Thurman Christopher
Published: March 2007

This essay was runner‐up in the 2006 Literature Compass Graduate Essay Prize, Shakespeare Section.

In Shakespeare's sonnets, sustained self‐reflexive deliberation on the nature of poetic representation is at times figured in terms of the nascent capitalism of early modern England: an intersection of ‘mimesis’ and ‘economics’ that is manifested in images of usury found in a number of the sonnets. This article surveys critical responses (by David Hawkes, James Dawes, Thomas Greene, John Mischo, Howard Felperin and others) that offer some insight into this aspect of Shakespeare's work. In doing so, the article attempts to reconcile potentially divergent perspectives on Shakespeare; it also suggests new ways in which the sonnets can be read, revisiting the relationship of the speaker/poet not only to certain figures in the sonnet sequence (the ‘fair youth’ and the ‘dark lady’) but also – perhaps more importantly – to his own poetic enterprise.
Fiction and Autobiography in Mary Hays'sMemoirs of Emma Courtney(1796)
Authors: Green Georgina
Published: March 2007

This essay was runner‐up in the 2006Literature CompassGraduate Essay Prize, Romanticism Section.

Although current critical strictures prohibit the reading of biography between the lines of fiction, Mary Hays'sMemoirs of Emma Courtney(1796) demands that we do so. The novel is laced with autobiography. The novel developed out of a suggestion by the philosopher William Godwin that Hays write a sketch of her life in order to challenge her ‘habitual melancholy’. Thus, althoughEmma Courtneyis not an autobiography in the strictest sense of the term, the discourse of autobiography is fundamental to it.Emma Courtneyreproduces almost verbatim much of Hays's correspondence. The novel is literally sourced from life, quilted from the textual acts of that life, its letters. The autobiographical mode used by the novel transpires into an investigation of the relationship between fiction and reality. Godwin's mentoring of Hays illuminates this complex relationship between autobiography and fiction. Godwin's criticism of Hays's novel crystallises into a debate about reality. In their dialogue, Hays defends the imagination as a valid, and more importantly, inevitable part of experience. This enquires into the very possibility of the Godwinian ‘virtue’ of self‐knowledge by making the Real itself problematic.
Reproductive efficiency in grazing lactating dairy cows under a programmed reproductive management system
Authors: Cavestany D , Betancour H , Blanc JE , Lemaire C , Slavica J , Moreira F , Piaggio J , Risco C
Published: March 2007

Objective  To evaluate the effectiveness of a reproductive management program consisting of combinations of Ovsynch/TAI and prostaglandin (PG) F2α treatments in Holstein dairy cows under a pasture‐based dairying system.

Design  Field trial.

Procedure  A total of 1177 cows in 8 commercial dairy farms were randomly allocated to control and treatment groups. Treatment group cows received one of two interventions depending upon the number of days postpartum (DPP) before the planned start of breeding. Cows more than 50 DPP by the planned start of breeding received the Ovsynch/TAI treatment, consisting of gonadotrophin releasing hormone (GnRH) – PGF2α– GnRH plus timed artificial insemination. Cows between 40 and 50 DPP received a PGF2α treatment followed by oestrus detection and, if the cow was not seen in oestrus, the cow received a second PGF2α 14 days later. Control cows were submitted to twice a day heat detection followed by artificial insemination. The experimental period was the start of the breeding season plus 21 days for cows over 50 DPP at the start of breeding, and was 40–61 DPP for cows that calved later and passed their voluntary waiting period after the start of the breeding season.

Results  Submission rate was higher for the treated group than for the control group (84.9% vs. 55.1%; P < 0.0001), as was the conception rate (51.0% vs. 46.1%; P < 0.03). Due to farm variations, pregnancy rate was similar in both groups (38.5% vs. 28.2%; P > 0.1). Within the treated group, conception rate and pregnancy rate of the cows inseminated after a PGF2α were higher than for timed artificial inseminated cows (51.4% vs. 32.6%; P < 0.001), and (37.8% vs. 32.6%; P < 0.001).

Conclusion  A programmed reproductive management protocol may improve reproductive efficiency in dairy farms with seasonal breeding, by increasing submission and conception rates at the beginning of the breeding season and/or at the end of the voluntary waiting period. Fertility of cows bred after a PGF2α synchronised heat was greater than after an Ovsynch/TAI protocol.
Skeletal and neurological malformations in pigs congenitally infected with Menangle virus
Authors: Philbey AW , Ross AD , Kirkland PD , Love RJ
Published: March 2007

Objective  To describe the pathological findings in stillborn piglets and fetuses delivered by sows naturally infected with Menangle virus, a recently recognised Paramyxovirus.

Design  Observations of the gross and microscopic pathology of natural disease.

Procedure  Postmortem examinations were performed on 49 stillborn piglets, 35 mummified or semi‐mummified full‐term fetuses and 6 aborted fetuses from 20 litters at a 2600‐sow intensive piggery in New South Wales during an outbreak of reproductive disease from June to September 1997. Body weights, crown‐rump lengths and gross pathological changes were recorded. Tissues, including brain and spinal cord, were processed for histopathological examination.

Results  Litters with reduced numbers of live born piglets had mummified fetuses and stillborn piglets. Affected stillborn and aborted piglets frequently had arthrogryposis, craniofacial and spinal deformities, pulmonary hypoplasia and degeneration of the brain and spinal cord. Intranuclear and intracytoplasmic inclusion bodies were observed in neurones and other cells in the brain and spinal cord in association with extensive degeneration, necrosis, infiltration of macrophages and gliosis.

Conclusions  In utero infection of piglets with Menangle virus is associated with severe skeletal and neurological malformations.
Behaviours of pulmonary sensory receptors during development of acute lung injury in the rabbit
Authors: Lin Shuxin , Walker Jerome , Xu Ling , Gozal David , Yu Jerry
Published: March 2007

We tested the hypothesis that oleic acid‐induced acute lung injury activates pulmonary nociceptors, that is, C fibre receptors (CFRs) and high‐threshold Aδ fibre receptors (HTARs). Single‐unit activity was recorded in the cervical vagus nerve and assessed before and after injecting oleic acid (75 μl kg−1i.v.) into anaesthetized, open‐chest, mechanically ventilated rabbits. Unit activities increased within seconds and peaked within a few minutes (from 0.3 ± 0.1 to 1.4 ± 0.9 impulses s−1 for CFRs and from 0.5 ± 0.1 to 1.7 ± 0.3 impulses s−1 for HTARs, both n= 8 and P < 0.05). These activities were sustained while pulmonary oedema developed and dynamic lung compliance decreased over the 90 min observation period. Activities in slowly adapting receptors and rapidly adapting receptors were also increased; however, their responsiveness to airway pressure stimulation decreased progressively. We conclude that pulmonary nociceptors are stimulated during acute lung injury. The dual nociceptor system, consisting of both non‐myelinated CFRs and myelinated HTARs, may play an important role in the pathophysiological process of acute lung injury‐induced respiratory responses.
Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT1Areceptor agonist in neonatal piglets
Authors: Curran Aidan K. , Leiter J. C.
Published: March 2007

Inhibition of neurones in the ventral medulla accentuates the respiratory inhibition associated with acute blood pressure elevation in piglets. Activation of presynaptic 5‐HT1Areceptors inhibits serotonergic neurones in the ventral medulla and caudal raphé, and we tested the hypothesis that administration of 8‐hydroxydipropylaminotetralin (8‐OH‐DPAT), a 5‐HT1Aagonist, within the rostroventral medulla and caudal raphé would enhance baroreceptor‐mediated inhibition of respiratory activity in decerebrate, neonatal piglets. Baroreceptor stimulation was achieved by inflating a balloon in the distal aorta to elevate carotid blood pressure. After two to four control trials of baroreceptor stimulation, each piglet was given either a single intravenous (i.v.) dose of 10 μg kg–18‐OH‐DPAT or treated by adding 10 or 30 mm8‐OH‐DPAT to the dialysate for ∼10 min to inhibit serotonergic neurones, after which the baroreceptor stimulation trials were repeated. Baroreceptor stimulation reduced respiratory activity, particularly the respiratory frequency, which diminished from 35.7 ± 3.3 to 33.8 ± 3.1 breaths min–1(P< 0.02) and, followingi.v.8‐OH‐DPAT, baroreceptor‐mediated inhibition of respiratory output was significantly accentuated (P< 0.05); the respiratory frequency declined from 34.5 ± 3.6 to 26.5 ± 2.9 breaths min–1. Increasing aortic blood pressure reduced the respiratory frequency (P< 0.01), but focal dialysis of 10 or 30 mm8‐OH‐DPAT had, on average, no effect on the ventilatory inhibition associated with an acute elevation of blood pressure. We conclude that activation of 5‐HT1Areceptors after systemic administration of 8‐OH‐DPAT enhanced baroreflex‐mediated inhibition of ventilation, but this effect cannot be attributed to 5‐HT1Areceptor activation within the rostroventral medulla and caudal raphé.
Experimental Investigations on a Hydrogen-Diesel Dual Fuel Engine at Different Compression Ratios
Authors: Masood M. , Mehdi S. N. , Ram Reddy P.
Published: March 2007

An experimental investigation was carried out on a computer interfaced single cylinder variable compression ratio, compression ignition engine to optimize the performance characteristics and to find the useful higher compression ratio (UHCR) with hydrogen-diesel dual fuel mode. Experimentations were conducted on five different compression ratios and the performance characteristics were calculated. The effect of blending on NOx, HC, CO, and particulate matter were measured and reported. The rate of heat release and speed of combustion with increase in compression ratio with simultaneous increase in hydrogen substitution were measured. Intake temperature of air was increased and for three different temperatures, the effect of increase in temperature of air-hydrogen mixture on NOx were studied and found that there was a sharp increase in the NOx value as the inlet temperature was increased from 65 to 85°C.
Gas Turbine Fogging Technology: A State-of-the-Art Review—Part I: Inlet Evaporative Fogging—Analytical and Experimental Aspects
Authors: Bhargava R. K. , Meher-Homji C. B. , Chaker M. A. , Bianchi M. , Melino F. , Peretto A. , Ingistov S.
Published: March 2007

Ambient temperature strongly influences gas turbine power output causing a reduction of around 0.50% to 0.90% for every 1°C of temperature rise. There is also a significant increase in the gas turbine heat rate as the ambient temperature rises, resulting in an increased operating cost. As the increase in power demand is usually coincident with high ambient temperature, power augmentation during the hot part of the day becomes important for independent power producers, cogenerators, and electric utilities. Evaporative and overspray fogging are simple, proven, and cost effective approaches for recovering lost gas turbine performance. A comprehensive review of the current understanding of the analytical, experimental, and practical aspects including climatic and psychrometric aspects of high-pressure inlet evaporative fogging technology is provided. A discussion of analytical and experimental results relating to droplets dynamics, factors affecting droplets size, and inlet duct configuration effects on inlet evaporative fogging is covered in this paper. Characteristics of commonly used fogging nozzles are also described and experimental findings presented.
Gas Turbine Fogging Technology: A State-of-the-Art Review—Part III: Practical Considerations and Operational Experience
Authors: Bhargava R. K. , Meher-Homji C. B. , Chaker M. A. , Bianchi M. , Melino F. , Peretto A. , Ingistov S.
Published: March 2007

The strong influence of ambient temperature on the output and heat rate of a gas turbine has popularized the application of inlet fogging and overspray for power augmentation. In this paper we focus on practical considerations for the implementation of the fogging technology such as water quality requirements, foreign object damage, gas turbine inlet icing, intake duct design, changes in compressor performance characteristics, and blade coating distress problems. It also provides a checklist for users and project developers to facilitate the design and implementation of fogging systems. In addition, in this paper we cover operational experience and review the work pursued by gas turbine OEMs in the field of fogging technology. A list of unresolved issues and ongoing research related to the fogging technology is also provided.
Application of Hot-Wire Anemometry in a Blow-Down Turbine Facility
Authors: Yasa T. , Paniagua G. , Dénos R.
Published: March 2007

In order to test HP turbine stages under engine representative conditions on a heat transfer point of view, blow-down test rigs are often used. In these rigs the evolution of gas temperature, pressure, and density is similar to a step function. Hence, the use of hot-wires, which are sensitive to flow velocity, density, and temperature, is more difficult than in an incompressible flow at constant temperature. This investigation describes how the data reduction can be performed in such an environment in order to extract the velocity. The gas temperature is measured with a thermocouple and the gas density is derived from the measurement of the total pressure thanks to an iterative procedure. Once the velocity is derived, the turbulence can be computed. The effectiveness of the method is first demonstrated in a heated jet where both pressure and temperature are varied. Tests in the turbine facility are performed at turbine inlet temperatures of 480K. Thus, overheat ratios up to 1.9 had to be used, leading to a very high temperature of the tungsten platinum coated wire. The aging of the probe was very fast, causing a drift in the voltage output between the successive tests. A technique is proposed to minimize the aging effect. It consists in adapting the calibration based on the resistance of the wire measured before each test. Measurements were carried out at the turbine inlet and rotor outlet. At the turbine inlet, velocity radial profiles are obtained together with measurements of the turbulence intensity. The time-averaged data is compared with pneumatic probe measurements. At the rotor exit, the time-resolved periodic velocity fluctuations are analyzed using a phase-locked average technique.
LES and RANS Investigations Into Buoyancy-Affected Convection in a Rotating Cavity With a Central Axial Throughflow
Authors: Sun Zixiang , Lindblad Klas , Chew John W. , Young Colin
Published: March 2007

The buoyancy-affected flow in rotating disk cavities, such as occurs in compressor disk stacks, is known to be complex and difficult to predict. In the present work, large eddy simulation (LES) and unsteady Reynolds-averaged Navier-Stokes (RANS) solutions are compared to other workers’ measurements from an engine representative test rig. The Smagorinsky-Lilly model was employed in the LES simulations, and the RNG k-ε turbulence model was used in the RANS modeling. Three test cases were investigated in a range of Grashof number Gr=1.87 to 7.41×108 and buoyancy number Bo=1.65 to 11.5. Consistent with experimental observation, strong unsteadiness was clearly observed in the results of both models; however, the LES results exhibited a finer flow structure than the RANS solution. The LES model also achieved significantly better agreement with velocity and heat transfer measurements than the RANS model. Also, temperature contours obtained from the LES results have a finer structure than the tangential velocity contours. Based on the results obtained in this work, further application of LES to flows of industrial complexity is recommended.
Design and Off-Design Characteristics of the Alternative Recuperated Gas Turbine Cycle With Divided Turbine Expansion
Authors: Hwang Sung Hoon , Yoon Soo Hyoung , Kim Tong Seop
Published: March 2007

In order to fully address the characteristics of the alternative recuperated cycle with divided turbine expansion, both design and off-design analyses have been performed. Two types of mechanical design are assumed: two shaft and single shaft. In particular, optimal pressure ratio division between the high- and low-pressure turbines is evaluated for the single-shaft configuration. It is predicted that the alternative recuperated cycle hardly exhibits sensible design efficiency advantage over the conventional recuperated cycle for moderate turbine inlet conditions and with usual component performances. An advantage of the alternative cycle with single-shaft design is that thermal efficiency is less sensitive to compressor pressure ratio compared to other configurations, and we can also have flexibility in the turbine division without much efficiency loss. The part load analyses have been carried out with the aid of realistic component maps and models for off-design operation. In addition to the general fuel only control, a variable speed control is assumed as the part load operating strategy of the single-shaft configuration. Obvious advantage with the alternative cycle is observed in the variable speed operation of the single-shaft design. With this strategy, the part load efficiency of the alternative cycle is far superior to the conventional cycle. Almost constant efficiency is predicted for a wide power range.
Experimental Validation of a Common-Rail Injector Model in the Whole
Operation Field
Authors: Coppo Marco , Dongiovanni Claudio
Published: March 2007

The present study deals with the definition of an accurate mathematical model of a production common-rail-type injector for automotive diesel engines. The mathematical model defined in a previous work was refined, accounting for a broader range of effects on injector performance, thus allowing a more strict validation of the model predictions against experimental data. The geometry of the control-valve holes, crucial in determining the actual discharge coefficient, was accurately evaluated by means of silicone molds. The moving mechanical components of the injector, such as control valve, needle, and pressure rod were modeled using the mass–spring–damper scheme. The axial deformation under pressure of needle, pressure rod, nozzle and injector body was modeled. This effect was found to also affect the control valve device operation, and was properly accounted for. The model obtained was implemented in Simulink; the ordinary differential equations were solved by means of the numerical differentiation formulas implicit scheme of second-order accuracy, while the partial differential equations were integrated using the finite-difference Lax–Friedrichs method. In order to obtain sufficient data for validating the model in its entire operation field, two separate sets of tests were carried out. In the first analysis, a constant reference pressure was imposed in the rail, and the injector energizing time was progressively increased from values relative to small pilot injections to values characteristic of large main injections. The injected volume per stroke was measured by means of a mean delivery meter (EMI) device. During the second set of tests, the injector was mounted on a flow rate meter (EVI) device so as to measure the injection law. Electric current flowing through the injector solenoid, oil pressure in the common rail, and at the injector inlet, needle, and control valve lift were also gauged and recorded. The good agreement between numerical and experimental results allowed the use of the model to gain greater insight into the mechanisms and phenomena that regulate injector behavior. The nozzle hole discharge coefficient dependence upon time and needle lift was discussed, and the trends were presented in several working conditions. The flow in the control volume holes was studied, in order to determine whether cavitation occurs or not, giving an answer to a long disputed topic. Finally, the effects of injector deformation caused by fuel pressure on performance were investigated.
Gas Turbine Combustion Technology Reducing Both Fuel-NOx and Thermal-NOx Emissions for Oxygen-Blown IGCC With Hot/Dry Synthetic Gas Cleanup
Authors: Hasegawa Takeharu , Tamaru Takashi
Published: March 2007

In order to improve the thermal efficiency of the oxygen-blown integrated gasification combined cycle (IGCC) and to meet stricter environmental restrictions among cost-effective options, a hot/dry synthetic gas cleanup is one of the most hopeful choices. The flame temperature of medium-Btu gasified fuel used in this system is high so that NOx formation by nitrogen fixation results to increase significantly. Additionally, the gasified fuel contains nitrogenous compound, as ammonia, and it produces nitrogen oxides, the fuel NOx, in the case of employing the hot/dry gas cleanup. Low NOx combustion technology to reduce both fuel-NOx and thermal-NOx emissions has been required to protect the environment and ensure low cost operations for all kinds of oxygen-blown IGCC. In this paper, we have demonstrated the effectiveness of two-stage combustion and nitrogen injection techniques, and also showed engineering guidelines for the low-NOx combustor design of oxygen-blown gasified, medium-Btu fuels. The main results obtained are as follows: (1) Based on the basic combustion tests using a small diffusion burner, we clarified that the equivalence ratio at the primary combustion zone has to be adjusted according to the fuel conditions, such as methane concentration, CO∕H2 molar ratio, and calorific values of gasified fuels in the case of the two-stage combustion method for reducing fuel-NOx emissions. (2) From the combustion tests of the medium-Btu fueled combustor, two-stage combustion with nitrogen direct injection into the combustor results in reductions of NOx emissions to 34ppm (corrected at 16% O2) or less under the gas turbine operational conditions of 25% load or higher for IGCC in the case where the gasified fuel contains 0.1% methane and 500ppm of ammonia. Through nitrogen direct injection, the thermal efficiency of the plant improved by approximately 0.3% (absolute), compared with the case where nitrogen was premixed with gasified fuel. The CO emission concentration decreased drastically, as low as 20ppm, or combustion efficiency was kept higher than 99.9%. The above results have shown that a two-stage combustion method with nitrogen direct injection is very effective for reducing both fuel-NOx and thermal-NOx emissions at once in IGCC, and it shows the bright prospects for low NOx and stable combustion technology of medium-Btu fuel.
A Technoeconomic Analysis of Different Options for Cogenerating Power in Hydrogen Plants Based on Natural Gas Reforming
Authors: Corradetti Alessandro , Desideri Umberto
Published: March 2007

Steam methane reforming is the most common process for producing hydrogen in the world. It currently represents the most efficient and mature technology for this purpose. However, because of the high investment costs, this technology is only convenient for large sizes. Furthermore, the cooling of syngas and flue gas produce a great amount of excess steam, which is usually transferred outside the process, for heating purposes or industrial applications. The opportunity of using this additional steam to generate electric power has been studied in this paper. In particular, different power plant schemes have been analyzed, including (i) a Rankine cycle, (ii) a gas turbine simple cycle, and (iii) a gas-steam combined cycle. These configurations have been investigated with the additional feature of CO2 capture and sequestration. The reference plant has been modeled according to state-of-the-art of commercial hydrogen plants: it includes a prereforming reactor, two shift reactors, and a pressure swing adsorption unit for hydrogen purification. The plant has a conversion efficiency of ∼75% and produces 145,000Sm3∕hr of hydrogen (equivalent to 435MW on the lower-heating-volume basis) and 63t∕hr of superheated steam. The proposed power plants generate, respectively, 22MW (i), 36MW (ii), and 87MW (iii) without CO2 capture. A sensitivity analysis was carried out to determine the optimum size for each configuration and to investigate the influence of some parameters, such as electricity, natural gas, and steam costs.
Characterization of Porous Carbon Foam as a Material for Compact Recuperators
Authors: Straatman A. G. , Gallego N. C. , Yu Q. , Thompson B. E.
Published: March 2007

Experiments are presented to quantify the convective heat transfer and hydrodynamic loss that is obtained by forcing water through blocks of porous carbon foam (PCF) heated from one side. The experiments were conducted in a small-scale water tunnel instrumented to measure the pressure drop and temperature rise of the water passing through the blocks and the base temperature and heat flux into the foam block. In comparison to similar porosity aluminum foam, the present results indicate that the pressure drop across the porous carbon foam is higher due to the large hydrodynamic loss associated with the cell windows connecting the pores, but the heat transfer performance suggests that there may be a significant advantage to using PCF over aluminum foam for extended surface convection elements in recuperators and electronic cooling devices.
Experimental Investigation of Mode Shape Sensitivity of an Oscillating Low-Pressure Turbine Cascade at Design and Off-Design Conditions
Authors: Vogt Damian M. , Fransson Torsten H.
Published: March 2007

The effect of negative incidence operation on mode shape sensitivity of an oscillating low-pressure turbine rotor blade row has been studied experimentally. An annular sector cascade has been employed in which the middle blade has been made oscillating in controlled three-dimensional rigid-body modes. Unsteady blade surface pressure data were acquired at midspan on the oscillating blade and two pairs of nonoscillating neighbor blades and reduced to aeroelastic stability data. The test program covered variations in reduced frequency, flow velocity, and inflow incidence; at each operating point, a set of three orthogonal modes was tested such as to allow for generation of stability plots by mode recombination. At nominal incidence, it has been found that increasing reduced frequency has a stabilizing effect on all modes. The analysis of mode shape sensitivity yielded that the most stable modes are of bending type with axial to chordwise character, whereas high sensitivity has been found for torsion-dominated modes. Negative incidence operation caused the flow to separate on the fore pressure side. This separation was found to have a destabilizing effect on bending modes of chordwise character, whereas an increase in stability could be noted for bending modes of edgewise character. Variations of stability parameter with inflow incidence have hereby found being largely linear within the range of conditions tested. For torsion-dominated modes, the influence on aeroelastic stability was close to neutral.
Lifetime Prediction of Components Including Initiation Phase
Authors: Besel Michael , Brueckner-Foit Angelika
Published: March 2007

The lifetime distribution of a component subjected to fatigue loading is calculated using a micromechanics model for crack initiation and a fracture mechanics model for crack growth. These models are implemented in a computer code which uses the local stress field obtained in a finite-element analysis as input data. Elemental failure probabilities are defined which allow us to identify critical regions and are independent of mesh refinement. An example is given to illustrate the capabilities of the code. Special emphasis is put on the effect of the initiation phase on the lifetime distribution.
CFD Investigation of Gear Pump Mixing Using Deforming/Agglomerating Mesh
Authors: Strasser Wayne
Published: March 2007

A moving-deforming grid study was carried out using a commercial computational fluid dynamics (CFD) solver, FLUENT® 6.2.16. The goal was to quantify the level of mixing of a lower-viscosity additive (at a mass concentration below 10%) into a higher-viscosity process fluid for a large-scale metering gear pump configuration typical in plastics manufacturing. Second-order upwinding and bounded central differencing schemes were used to reduce numerical diffusion. A maximum solver progression rate of 0.0003 revolutions per time step was required for an accurate solution. Fluid properties, additive feed arrangement, pump scale, and pump speed were systematically studied for their effects on mixing. For each additive feed arrangement studied, the additive was fed in individual stream(s) into the pump-intake. Pump intake additive variability, in terms of coefficient of spatial variation (COV), was >300% for all cases. The model indicated that the pump discharge additive COV ranged from 45% for a single centerline additive feed stream to 5.5% for multiple additive feed streams. It was found that viscous heating and thermal/shear-thinning characteristics in the process fluid slightly improved mixing, reducing the outlet COV to 3.2% for the multiple feed-stream case. The outlet COV fell to 2.0% for a half-scale arrangement with similar physics. Lastly, it was found that if the smaller unit’s speed were halved, the outlet COV was reduced to 1.5%.
Dynamic Self-Assembly of Spinning Particles
Authors: Climent Eric , Yeo Kyongmin , Maxey Martin R. , Karniadakis George E.
Published: March 2007

This paper presents a numerical study of the dynamic self-assembly of neutrally buoyant particles rotating in a plane in a viscous fluid. The particles experience simultaneously a magnetic torque that drives their individual spinning motion, a magnetic attraction toward the center of the domain, and flow-induced interactions. A hydrodynamic repulsion balances the centripetal attraction of the magnetized particles and leads to the formation of an aggregate of several particles that rotates with a precession velocity related to the inter-particle distance. This dynamic self-assembly is stable (but not stationary) and the morphology depends on the number of particles. The repulsion force between the particles is shown to be the result of the secondary flow generated by each particle at low but nonzero Reynolds number. Comparisons are made with analogous experiments of spinning disks at a liquid–air interface, where it is found that the variation in the characteristic scales of the aggregate with the rotation rate of individual particles are consistent with the numerical results.
Torque and Bulk Flow of Ferrofluid in an Annular Gap Subjected to a Rotating Magnetic Field
Authors: Chaves Arlex , Gutman Fernando , Rinaldi Carlos
Published: March 2007

We report analysis and measurements of the torque and flow of a ferrofluid in a cylindrical annulus subjected to a rotating magnetic field perpendicular to the cylinder axis. The presence of the inner cylinder results in a nonuniform magnetic field in the annulus. An asymptotic analysis of the ferrohydrodynamic torque and flow assuming linear magnetization and neglecting the effect of couple stresses indicated that the torque should have a linear dependence on field frequency and quadratic dependence on field amplitude. To the order of approximation of the analysis, no bulk flow is expected in the annular gap between stationary cylinders. Experiments measured the torque required to restrain a polycarbonate spindle surrounded by ferrofluid in a cylindrical container and subjected to the rotating magnetic field generated by a two-pole magnetic induction motor stator, as a function of the applied field amplitude and frequency, and for various values of the geometric aspect ratios of the problem. The ultrasound velocity profile method was used to measure the azimuthal and axial velocity profiles in the ferrofluid contained in the annular gap of the apparatus. Flow measurements show the existence of a bulk azimuthal ferrofluid flow between stationary coaxial cylinders with a negligible axial velocity component. The fluid was found to corotate with the applied magnetic field. Both the torque and flow measurements showed power-of-one dependence on frequency and amplitude of the applied magnetic field. This analysis and these experiments indicate that the action of antisymmetric stresses is responsible for the torque measured on the inner cylinder, whereas the effect of body couples is likely responsible for bulk motion of the ferrofluid.
Ten-Year Surveillance of Pneumococcal Infections in Temuco, Chile: Implications for Vaccination Strategies
Authors: Inostroza Jaime , Illesca Vijna , Reydet Patricia , Vinet Ana Maria , Ossa Gonzalo , Muñoz Sergio , Thompson Terry , Sorensen Ricardo U.
Published: March 2007

We monitored
Streptococcus pneumoniae
serotypes causing invasive infections in patients admitted to one hospital in southern Chile during a 10-year period (1994 to 2004). All specimens isolated from patients with invasive
S. pneumoniae
infections were serotyped at the CDC in Atlanta, GA. A total of 508 isolates belonged to 58 serotypes. There were 95 infections in patients <2 years old, 33 infections in patients 2 to 4 years old, 61 infections in patients 5 to 14 years old, 66 infections in patients 15 to 44 years old, 134 infections in patients 45 to 64 years old, and 120 infections in patients ≥65 years old. The 10 serotypes isolated with the highest frequency in all groups were, in decreasing order, 1, 3, 14, 5, 19F, 6B, 7F, 12F, 23F, and 6A. The 10 most frequent isolates in children under 2 years of age were 1, 6B, 14, 19F, 5, 23F, 6A, 9V, and 7F. In patients ≥65 years old, the most common serotypes were 3, 7F, 1, 14, 19A, 23F, 19F, 35B, 4, and 5. Penicillin resistance was detected in 14 (2.7%) clinical specimens isolated since 1998, with 13 resistant strains identified since 2001. Vaccine coverage for the 7-valent conjugate vaccine was 42% for children <2 years of age. This study is important for the design of vaccines for this region and to evaluate public health measures to decrease pneumococcal infections.
Recombinant Polypeptide Antigen-Based Immunoglobulin G Enzyme-Linked Immunosorbent Assay for Serodiagnosis of Dengue
Authors: Dos Santos Flavia B. , Nogueira Rita Maria R. , Lima Monique R. Q. , De Simone Thatiane S. , Schatzmayr Hermann G. , Lemes Elezer M. B. , Harris Eva , Miagostovich Marize P.
Published: March 2007

We have developed an indirect enzyme-linked immunosorbent assay for detection of anti-dengue virus (DENV) immunoglobulin G antibodies using four recombinant DENV envelope polypeptides as antigens, which demonstrated a sensitivity of 89.4% and a specificity of 93.3%. These easily produced antigens are a feasible, cost-effective alternative for generating reagents for dengue serological tests.
Association of the Pneumococcal Pilus with Certain Capsular Serotypes but Not with Increased Virulence
Authors: Basset Alan , Trzcinski Krzysztof , Hermos Christina , O'Brien Katherine L. , Reid Raymond , Santosham Mathuram , McAdam Alexander J. , Lipsitch Marc , Malley Richard
Published: March 2007

The recent discovery of a mobile genetic element encoding a pilus-like structure in
Streptococcus pneumoniae
and the demonstration of a role for the pilus in virulence in mice have led to the proposal of the use of the pilus as a candidate pneumococcal vaccine. We examined the frequency of occurrence of the pneumococcal pilus, as determined by the presence of the
rrgC
gene, and analyzed its association with virulence, capsular serotypes, and multilocus sequence types in the American Indian pneumococcal collection and isolates of
S. pneumoniae
from blood cultures collected at Children's Hospital Boston. Overall, 21.4% of strains in the American Indian collection had the
rrgC
gene, but there was no difference between isolates obtained from the nasopharynx and those obtained from sterile sites (blood or cerebrospinal fluid). Vaccine-type strains were significantly more likely than non-vaccine-type strains to have this pilus gene (
P
< 0.001). Among isolates with identical multilocus sequence types, there was a high concordance (95%) between the multilocus sequence type and the presence or the absence of
rrgC
. Finally, in the era of the pneumococcal conjugate vaccine, the frequency of
rrgC
in isolates from Children's Hospital Boston has decreased significantly (42.8% before 2000 versus 21.3% after 2000;
P
= 0.019). Therefore, our data show that the pilus is present in a minority of strains and is associated with certain serotypes and that its frequency has been reduced by the conjugate pneumococcal vaccine.
Epidemiology and Outcomes of Community-Associated Methicillin-Resistant
Staphylococcus aureus
Infection
Authors: Davis S. L. , Perri M. B. , Donabedian S. M. , Manierski C. , Singh A. , Vager D. , Haque N. Z. , Speirs K. , Muder R. R. , Robinson-Dunn B. , Hayden M. K. , Zervos M. J.
Published: March 2007

Over a 2-year period (2003 to 2005) patients with community-associated methicillin-resistant
Staphylococcus aureus
(CA-MRSA) and community-acquired methicillin-susceptible
Staphylococcus aureus
(CA-MSSA) infections were prospectively identified. Patients infected with CA-MRSA (
n
= 102 patients) and CA-MSSA (
n
= 102 patients) had median ages of 46 and 53 years, respectively; the most common sites of infection in the two groups were skin/soft tissue (80 and 93%, respectively), respiratory tract (13 and 6%, respectively), and blood (4 and 1%, respectively). Fourteen percent of patients with CA-MRSA infections and 3% of patients with CA-MSSA infections had household contacts with similar infections (
P
< 0.01). Among the CA-MRSA isolates, the pulsed-field gel electrophoresis (PFGE) groups detected were USA300 (49%) and USA100 (13%), with 27 PFGE groups overall; 71% of the isolates were staphylococcal chromosome cassette
mec
(SCC
mec
) type IV, 29% were SCC
mec
type II, and 54% had the Panton-Valentine leucocidin (PVL) gene. Among the CA-MSSA isolates there were 33 PFGE groups, with isolates of the USA200 group comprising 11%, isolates of the USA600 group comprising 11%, isolates of the USA100 group comprising 10%, and isolates of the PVL type comprising 10%. Forty-six and 18% of the patients infected with CA-MRSA and CA-MSSA, respectively, were hospitalized (
P
< 0.001). Fifty percent of the patients received antibiotic therapy alone, 5% received surgery alone, 30% received antibiotics and surgery, 3% received other therapy, and 12% received no treatment. The median durations of antibiotic therapy were 12 and 10 days in the CA-MRSA- and CA-MSSA-infected patients, respectively; 48 and 56% of the patients in the two groups received adequate antimicrobial therapy, respectively (
P
< 0.001). The clinical success rates of the initial therapy in the two groups were 61 and 84%, respectively (
P
< 0.001); recurrences were more common in the CA-MRSA group (recurrences were detected in 18 and 6% of the patients in the two groups, respectively [
P
< 0.001]). CA-MRSA was an independent predictor of clinical failure in multivariate analysis (odds ratio, 3.4; 95% confidence interval, 1.7 to 6.9). In the community setting, the molecular characteristics of the
S. aureus
strains were heterogeneous. CA-MRSA infections were associated with a more adverse impact on outcome than CA-MSSA infections.
Operational Feasibility of Using Loop-Mediated Isothermal Amplification for Diagnosis of Pulmonary Tuberculosis in Microscopy Centers of Developing Countries
Authors: Boehme Catharina C. , Nabeta Pamela , Henostroza German , Raqib Rubhana , Rahim Zeaur , Gerhardt Martina , Sanga Erica , Hoelscher Michael , Notomi Tsugunori , Hase Tetsu , Perkins Mark D.
Published: March 2007

The characteristics of loop-mediated isothermal amplification (LAMP) make it a promising platform for the molecular detection of tuberculosis (TB) in developing countries. Here, we report on the first clinical evaluation of LAMP for the detection of pulmonary TB in microscopy centers in Peru, Bangladesh, and Tanzania to determine its operational applicability in such settings. A prototype LAMP assay with simplified manual DNA extraction was evaluated for accuracy and ease of use. The sensitivity of LAMP in smear- and culture-positive sputum specimens was 97.7% (173/177 specimens; 95% confidence interval [CI], 95.5 to 99.9%), and the sensitivity in smear-negative, culture-positive specimens was 48.8% (21/43 specimens; CI, 33.9 to 63.7%). The specificity in culture-negative samples was 99% (500/505 specimens; CI, 98.1 to 99.9%). The average hands-on time for testing six samples and two controls was 54 min, similar to that of sputum smear microscopy. The optimal amplification time was 40 min. No indeterminate results were reported, and the interreader variability was 0.4%. Despite the use of a single room without biosafety cabinets for all procedures, no DNA contamination was observed. The assay was robust, with high end-point stability and low rates of test failure. Technicians with no prior molecular experience easily performed the assay after 1 week of training, and opportunities for further simplification of the assay were identified.
Genetic Diversity in a
Bacillus anthracis
Historical Collection (1954 to 1988)
Authors: Sue David , Marston Chung K. , Hoffmaster Alex R. , Wilkins Patricia P.
Published: March 2007

Bacillus anthracis
, the etiologic agent of anthrax, has been widely described as a genetically monomorphic species. We used both multiple-locus variable-number tandem-repeat analysis (MLVA) and
pagA
gene sequencing to determine the genetic diversity of a historical collection of
B. anthracis
isolates collected from the 1950s to the 1980s from various geographic locations and sources. We sequenced the
pagA
gene of 124 diverse
B. anthracis
isolates and found all previously identified
B. anthracis pagA
types except type 4. Sixty-three of the 124
B. anthracis
strains were identified as
pagA
type 6, while 44 were
pagA
type 5, 12 were
pagA
type 1, and individual isolates were identified for types 2 and 3, respectively. Two new
pagA
genotypes were discovered in three environmental isolates within the historical collection. Two isolates had the same new genotype, and an additional isolate produced a second new genotype. MLVA detected 22 previously described genotypes in the historical collection. In addition, 33 new MLVA genotypes were found. For 11 isolates, an MLVA genotype could not be assigned because one or more alleles did not amplify. While only two additional
B. anthracis pagA
types were identified, in two instances, the use of
pagA
sequencing discriminated isolates with the same MLVA genotype. MLVA revealed that 39 of the 124 isolates were previously undocumented genotypes and that 1 isolate was found to be in the C cluster when it was subtyped by MLVA.
Putative Terminase Subunits of Herpes Simplex Virus 1 Form a Complex in the Cytoplasm and Interact with Portal Protein in the Nucleus
Authors: Yang Kui , Homa Fred , Baines Joel D.
Published: March 2007

Herpes simplex virus (HSV) terminase is an essential component of the molecular motor that translocates DNA through the portal vertex in the capsid during DNA packaging. The HSV terminase is believed to consist of the U
L
15, U
L
28, and U
L
33 gene products (pU
L
15, pU
L
28, and pU
L
33, respectively), whereas the HSV type 1 portal vertex is encoded by U
L
6. Immunoprecipitation reactions revealed that pU
L
15, pU
L
28, and pU
L
33 interact in cytoplasmic and nuclear lysates. Deletion of a canonical nuclear localization signal (NLS) from pU
L
15 generated a dominant-negative protein that, when expressed in an engineered cell line, decreased the replication of wild-type virus up to 80-fold. When engineered into the genome of recombinant HSV, this mutation did not interfere with the coimmunoprecipitation of pU
L
15, pU
L
28, and pU
L
33 from cytoplasmic lysates of infected cells but prevented viral replication, most nuclear import of both pU
L
15 and pU
L
28, and coimmunoprecipitation of pU
L
15, pU
L
28, and pU
L
33 from nuclear lysates. When the pU
L
15/pU
L
28 interaction was reduced in infected cells by the truncation of the C terminus of pU
L
28, pU
L
28 remained in the cytoplasm. Whether putative terminase components localized in the nucleus or cytoplasm, pU
L
6 localized in infected cell nuclei, as viewed by indirect immunofluorescence. The finding that the portal and terminase do eventually interact was supported by the observation that pU
L
6 coimmunoprecipitated strongly with pU
L
15 and weakly with pU
L
28 from extracts of infected cells in 1.0 M NaCl. These data are consistent with the hypothesis that the pU
L
15/pU
L
28/pU
L
33 complex forms in the cytoplasm and that an NLS in pU
L
15 is used to import the complex into the nucleus where at least pU
L
15 and pU
L
28 interact with the portal to mediate DNA packaging.
Human Immunodeficiency Virus-Restricted Replication in Astrocytes and the Ability of Gamma Interferon To Modulate This Restriction Are Regulated by a Downstream Effector of the Wnt Signaling Pathway
Authors: Carroll-Anzinger Deborah , Kumar Anvita , Adarichev Vyacheslav , Kashanchi Fatah , Al-Harthi Lena
Published: March 2007

Astrocyte dysregulation correlates with the severity and the rate of human immunodeficiency virus (HIV)-associated dementia (HAD) progression, highlighting a pivotal role for astrocytes in HIV neuropathogenesis. Yet, astrocytes limit HIV, indicating that they posses an intrinsic molecular mechanism to restrict HIV replication. We previously established that this restriction can be partly overcome by priming astrocytes with gamma interferon (IFN-γ), which is elevated in the cerebral spinal fluid of HAD patients. We evaluated the mechanism of restrictive HIV replication in astrocytes and how IFN-γ priming modulates this restriction. We demonstrate that the downstream effector of Wnt signaling, T-cell factor 4 (TCF-4), is part of a transcriptional complex that is immunoprecipitated with HIV TAR-containing region in untreated astrocytes but not in IFN-γ-treated cells. Blocking TCF-4 activity with a dominant-negative mutant enhanced HIV replication by threefold in both the astrocytoma cell line U87MG and primary fetal astrocytes. Using a TCF-4 reporter plasmid, we directly demonstrate that Wnt signaling is active in human astrocytes and is markedly reduced by IFN-γ treatment. Collectively, these data implicate TCF-4 in repressing HIV replication and the ability of IFN-γ to regulate this restriction by inhibiting TCF-4. Given that TCF-4 is the downstream effector of Wnt signaling, harnessing Wnt signaling as an intrinsic molecular mechanism to limit HIV replication may emerge as a powerful tool to regulate HIV replication within and outside of the brain.