bluuebunny/crossref_metadata_2025 huggingface dataset:
Short Term Wind Speed Forecasting Based on Bayesian Model Averaging Method
Authors: Li Gong , Shi Jing , Zhou Junyi
Published: July 2010

Wind energy has been the world’s fastest growing source of clean and renewable energy in the past decade. One of the fundamental difficulties faced by power system operators, however, is the unpredictability and variability of wind power generation, which is closely connected with the continuous fluctuations of the wind resource. Good short-term wind speed forecasting methods and techniques are urgently needed since it is important for wind energy conversion systems in terms of the relevant issues associated with the dynamic control of the wind turbine and the integration of wind energy into the power system. This paper proposes the application of Bayesian Model Averaging (BMA) method in combining the one-hour-ahead short-term wind speed forecasts from different statistical models. Based on the hourly wind speed observations from one representative site within North Dakota, four statistical models are built and the corresponding forecast time series are obtained. These data are then analyzed by using BMA method. The goodness-of-fit test results show that the BMA method is superior to its component models by providing a more reliable and accurate description of the total predictive uncertainty than the original elements, leading to a sharper probability density function for the probabilistic wind speed predictions.
Correlation for Prediction of Peak Heat Flux Achieved With a Bi-Porous Wick
Authors: Amouzegar Ladan , Catton Ivan , Vadnjal Aleksander
Published: July 2010

In the past researchers noted three distinct stages of evaporative heat transfer in a bi-porous wick. The maximum heat transfer rate is postulated to occur at the end of the second stage when the maximum number of small pores interfaces the vapor space. For optimization purposes a reliable model that relates the maximum heat flux of a bi-porous wick to the wick material properties, wick geometry given with average large and small pore diameter, wick thickness, and working fluid properties is demanded. In this work, a semi-empirical model that relates the heat flux at the capillary limit to the wick material properties, working fluid properties and wick dimensions is further developed. The model is based on the hydrodynamics of the capillary limit. The result is employed to qualitatively and quantitatively optimize the wick parameters for some specific cases and the optimization can be further performed using the proposed model.
A Numerical Study of Swirling Buoyant Laminar Jets at Low Reynolds Numbers
Authors: Taub Gordon N. , Lee Hyungoo , Balachandar S. , Sherif S. A.
Published: July 2010

The effect of swirl on laminar buoyant jets with low Reynolds numbers is explored. Three dimensional direct numerical simulations are performed to solve the time-dependent, incompressible Navier-Stokes equations. We use a body fitted grid system and employ the finite volume method to discretize the governing equations. A second-order central difference scheme is employed for all spatial derivative terms. The numerical simulation is advanced in time by a fractional step method with the second-order Adams-Bashforth scheme for explicit-convection terms and the Crank-Nicholson scheme for implicit-diffusion terms. The amount of swirl and buoyancy is varied from zero to very large values and the effect on the velocity field, jet width, entrainment and vortex are examined. Comparisons with analytical and experimental models are discussed.
A Molecular Dynamics Simulation of Bubble Nucleation on Solid Surface in Explosive Boiling
Authors: Zou Yu , Huai Xiulan
Published: July 2010

A bubble nucleation on solid surface in explosive boiling is simulated by molecular dynamics method. Liquid water on a solid surface is heated until a bubble is nucleated. Liquid water is represented by 10368 simple point charge molecules, and the solid surface is represented by three layers of harmonic molecules which are arranged in an fcc style. The increasing rate of temperature is realized by the temperature control technology of the solid surface molecules. Temperature and pressure of water system is calculated in the process of bubble nucleation. A “ghost atom” is used to estimate the volume of the bubble void, and the diameters of the cavitation are calculated. The bubble growth rate is determined by statistics on the bubble diameters. It indicates that expanding and shrinking alternate all the time, which has a same trend as in an underwater blast. The nucleation rate of the simulation is estimated at 30 orders of magnitude by calculating the nucleation time and the volume of the bubble void. Radial distribution function in the process of nucleation indicates a measure of the structure of the water system in the process of bubble nucleation.
Molecular Dynamics Simulation for Homogenous Nucleation of Water and Liquid Nitrogen in Explosive Boiling
Authors: Zou Yu , Huai Xiulan
Published: July 2010

Molecular dynamics simulations are carried out to study the energy conversion in the homogeneous nucleation processes of the explosive boiling caused by laser heating. Liquid nitrogen and water are investigated as the working fluid. Velocity scaling method is applied to realize the laser heating process. Three influencing factors, the heat quantity into the system, the area of the laser heating zone and the initial equilibrium temperature of the liquid are analyzed. It is found that the conversion ratio of energy between heat quantity and potential energy is from 66% to 78% in the process of laser heating. The influence of the heat quantity into the system on the energy conversion of liquid nitrogen is the same in trend as that of water. The influence of the initial equilibrium temperature and the area of the laser heating zone on the liquid nitrogen is less than that of water. The difference of energy conversion between water and liquid nitrogen is pretty dramatic, which is because of the hydrogen bond formed by the Coulombic interaction among water molecules.
Experiments on the Velocity Field Around a Low Aspect Ratio Wing at Low Reynolds Numbers
Authors: Morse Daniel R. , Liburdy James A.
Published: July 2010

The flow structure around a low aspect ratio wing at low Reynolds numbers and a fixed angle of attack of 20° is discussed using flow visualization as well as Three-Component Time-Resolved Particle Image Velocimetry (3C TR PIV). Mean quantities and statistical measurements of velocity were obtained and used to describe the average and transient characteristics of the flow field. Effects of spanwise variation from centerline to wingtip and Reynolds number variation from 1.3×104 to 6.6×104 are discussed. The role of the wing tip vortices is observed to be large in a low aspect ratio wing. The transfer of momentum via Reynolds shear stresses is shown in the leading edge region. Normalized spanwise shear stresses associated with the wing tip vortices are observed to increase with increasing Reynolds number.
Modelica Based Dynamic Modeling of an Air-Side Economizer
Authors: Li Pengfei , Li Yaoyu , Seem John E.
Published: July 2010

For the heating, ventilating, and air conditioning (HVAC) systems for commercial buildings, the cooling coils in air handling units (AHU) account for a significant fraction of total building energy consumption and have a major impact on comfort conditions and maintenance costs. Development of cost-effective advanced control strategies will enhance the performance and efficiency of AHU. The control design process can be greatly facilitated with simulation on high-fidelity dynamic model prior to experimental validation and implementation. This paper presents a dynamic model for an air-side economizer. The model development was based on Dymola and AirConditioning Library with some revision on heat exchanger modeling. For chilled-water cooling coil modeling, the major challenges include the variation of coil surface conditions under flow rate changes and partially-dry-partially-wet operations. This study proposes a dynamic coil model that is capable of predicting cooling performances under fully dry, partially-dry-partially-wet, and fully wet conditions. Validation with experimental data from a benchmark study was conducted under both dry and wet surface conditions. The model predicted the experimental results quite well for both transient and steady-state behaviors. In addition, other moist air components, such as dampers, fans, ducts and room, were developed. Such transient model will lay a more quality foundation for controller validation at the simulation phase.
Tool Heat Fluxes During Cutting of A360 Using Beck’s Method
Authors: McCarty Sean C. , Woodbury Keith A. , Chou Y. Kevin
Published: July 2010

The energy released during mechanical cutting is carried away by the metal chips and conduction into the tool. This report focuses on determination of the heat fluxes into the tool during cutting using Beck’s method. A small thermocouple is used to measure the temperature rise on the surface of a cutting tool during turning of aluminum A360 cylinders. A detailed model of the tool in FLUENT is used to compute the sensitivity coefficients for the temperature response at the sensor location due to a unit heat flux disturbance at the cutting zone. These sensitivity coefficients are used in Beck’s method along with the measured temperature history, to determine the heat flux history at the cutting zone.
An Experimental Method for Making In Situ Spectral Emittance Measurements of Coal Ash Deposits
Authors: Moore Travis J. , Cundick Darron P. , Jones Matthew R. , Tree Dale R. , Maynes R. Daniel , Baxter Larry L.
Published: July 2010

An experimental procedure has been developed to make in situ spectral emittance measurements of coal ash deposits. Pulverized coal is injected into a down-fired, entrained-flow reactor. Ash accumulates on a probe placed in the reactor effluent. The spectral emittance of the ash layer is calculated using measurements of the surface temperature and the spectral emissive power of the deposit. Measurements of the spectral emissive power and the surface temperature are obtained using a Fourier transform infrared (FTIR) spectrometer. The methods used to extract the spectral emissive power and surface temperature from measured infrared spectra were validated using a blackbody radiator at known temperatures. The experimental procedure was then used to find the spectral emittance of a coal ash deposit formed under oxidizing conditions.
Global Bifurcations and Multipulse-Type Chaotic Dynamics in the Interactions of Two Flexural Modes of a Cantilever Beam
Authors: Li Shuangbao , Zhang Wei , Yao Minghui
Published: July 2010

Global bifurcations and multipulse-type chaotic dynamics in the interactions of two flexural modes of a cantilever beam are studied using the extended Melnikov method. The cantilever beam studied is subjected to a harmonic axial excitation and transverse excitations at the free end. After the governing nonlinear equations of nonplanar motion with parametric and external excitations are given, the Galerkin’s procedure based on the first flexural mode in each direction is applied to the partial differential governing equation to obtain a two-degree-of-freedom non-autonomous nonlinear system. The resonant case considered here is one-to-one internal resonance, principal parametric resonance-1/2 subharmonic resonance. The method of multiple scales is used to derive four first-order nonlinear ordinary differential equations governing the modulation of the amplitudes and phases of two interacting modes. After transforming the modulations equations into a suitable form, the extended Melnikov method is employed to show the existence of chaotic dynamics by identifying Silnikov-type multipulse jumping orbits in the perturbed phase space. We are able to obtain the explicit restrictions on the damping, forcing, and the detuning parameters, under which multipulse-type chaotic dynamics is to be expected. Physically, such jumping means sudden, large-amplitude departures of the beam from its planar oscillations. Numerical simulations indicate that there chaotic responses and jumping phenomenon in the nonlinear nonplanar oscillations of the cantilever beam.
Enhancing Students’ Energy Engineering Skills by Embedding Topics in Homework Exercises
Authors: Hodge B. K.
Published: July 2010

Experiences with including energy engineering topics embedded in homework assignments in a required course and an elective mechanical engineering course rather than in a dedicated and/or required energy engineering course are discussed. Examples of assignments containing energy engineering aspects from the two courses are presented and discussed. Salient energy engineering features of the examples are examined. The procedure is assessed as being an effective one to ensure that all mechanical engineering students at Mississippi State University have some exposure to energy engineering topics and concepts.
Simulation of Open Channel Turbulent Flow Over Bridge Decks and Formation of Scour Hole Beneath the Bridge Under Flooding Conditions
Authors: Adhikary Bishwadipa , Majumdar Pradip , Kostic Milivoje , Lottes Steven A.
Published: July 2010

This study is focused on the simulation of open channel turbulent flow over flooded laboratory scale bridge decks and formation of scour holes under various flooding conditions. Solutions for turbulent flow field are based on Reynolds Averaged Navier-Stokes (RANS) equations and turbulence closure models using the STAR-CD commercial computational fluid dynamics (CFD) software. An iterative computational methodology is developed for predicting equilibrium scour profiles using the single-phase flow model with a moving boundary formulation. The methodology relies on an empirical correlation for critical bed shear stress that is used to characterize the condition for onset of sediment motion and an effective bed roughness that is a function of sediment particle size. The computational model and iterative methodology were stable and converged to an equilibrium scour hole shape and size that compares reasonably well with experiment using a constant critical shear stress value.
Combined Effects of Non-Newtonian Rheology, Curvature and Fluid Inertia Forces on the Squeeze Film Behaviour
Authors: Manivasakan Vimala , Sumathi G.
Published: July 2010

The laminar squeeze flow of couple-stress fluids between a flat circular disc and an axisymmetric curved disc of arbitrary shape is taken into consideration. Based on the modified lubrication theory and the microcontinuum theory, the problem is solved analytically. The combined effects of fluid inertia forces, curvature and non-Newtonian couple stresses on the squeeze film behaviour are investigated through the variations in the Reynolds number, curvature and the couple stress parameters. Each of these effects and their combinations show a significant enhancement in the squeeze film behaviour and these are studied through their effects on the squeeze film pressure and the load carrying capacity of the fluid film as a function of time. It is understood that the operating life of the squeeze film discs are lengthened, especially for larger couple stress parameters, larger Reynolds numbers and concave nature of the curved discs.
A Critical Assessment of Computer Tools for Calculating Composite Wind Turbine Blade Properties
Authors: Chen Hui , Yu Wenbin , Capellaro Mark
Published: July 2010

Several computer tools are critically assessed for calculating the inertial and structural properties of wind turbine blades. The theoretical foundation of each tool is briefly summarized and the advantages and disadvantages of each tool are pointed out. Several benchmark examples are used to evaluate the performance of different tools. Such a systematic and critical assessment provides guidance for wind turbine blade engineers to choose the right tool for effective design and analysis of wind turbine blades.
Modal Analysis of a Gyroscopic System With Nonlinear Constraints
Authors: Brake M. R. , Wickert J. A.
Published: July 2010

A method for the modal analysis of continuous gyroscopic systems with nonlinear constraints is developed, which assumes that the nonlinear constraints can be expressed with piecewise-linear force-deflection profiles. Using this assumption, the mode shapes and natural frequencies are found for each state, and a mapping method based on the inner product of the mode shapes is developed to map the displacement of the system between states. To illustrate this method, a model for the vibration of a traveling string in contact with a piecewise-linear constraint is developed as an analog of the interaction between magnetic tape and a guide in data storage systems. Several design parameters of the guide are considered: flange clearance, stiffness, symmetry, and the guide’s position. Critical bifurcation thresholds exist, below which the system exhibits no chaotic behavior and is dominated by period one, symmetric behavior, and above which the system contains asymmetric, higher periodic motion with windows of chaotic behavior. These bifurcation thresholds are particularly pronounced for the transport speed, flange clearance, symmetry of the force deflection profile, and guide position.
Prognostication Based on Resistance-Spectroscopy for High Reliability Electronics Under Shock-Impact
Authors: Lall Pradeep , Lowe Ryan , Suhling Jeff , Goebel Kai
Published: July 2010

Leading indicators of failure have been developed based on high-frequency characteristics, and system-transfer function derived from resistance spectroscopy measurements during shock and vibration. The technique is intended for condition monitoring in high reliability applications where the knowledge of impending failure is critical and the risks in terms of loss-of-functionality are too high to bear. Previously, resistance spectroscopy measurements [Constable 1992, Lizzul 1994, Prassana 1995] have been used during thermal cycling tests to monitor damage progression due to thermo-mechanical stresses. The development of resistance spectroscopy based damage pre-cursors for prognostication under shock and vibration is new. In this paper, the high-frequency characteristics, and system transfer function based on resistance spectroscopy measurements have been correlated with the damage progression in electronics during shock and vibration. Packages being examined include ceramic area-array packages. Second level interconnect technologies examined include copper-reinforced solder column, SAC305 solder ball, and 90Pb10Sn high-lead solder ball. Assemblies have been subjected to 1500g, 0.5 ms pulse [JESD-B2111]. Continuity has been monitored in-situ during the shock test for identification of part-failure. Resistance spectroscopy based damage pre-cursors have been correlated with the optically measured transient strain based feature vectors. High speed cameras have been used to capture the transient strain histories during shock-impact. Statistical pattern recognition techniques have been used to identify damage initiation and progression and determine the statistical significance in variance between healthy and damaged assemblies. Models for healthy and damaged packages have been developed based on package characteristics. Data presented shows that high-frequency characteristics and system-transfer characteristics based on resistance spectroscopy measurements can be used for condition-monitoring, damage initiation and progression in electronic systems. A positive prognostic distance has been demonstrated for each of the interconnect technologies tested.
Response to Comments on “Differential Sensitivity to Human Communication in Dogs, Wolves, and Human Infants”
Authors: Topál József , Miklósi Ádám , Sümegi Zsófia , Kis Anna
Published: July 2010

The comments by Fiset and Marshall-Pescini
et al
. raise important methodological issues and propose alternative accounts for our finding of perseverative search errors in dogs. Not denying that attentional processes and local enhancement are involved in such object search tasks, we provide here new evidence and argue that dogs’ behavior is affected by a combination of factors, including specific susceptibility to human communicative signals.
Adaptation via Symbiosis: Recent Spread of a
Drosophila
Defensive Symbiont
Authors: Jaenike John , Unckless Robert , Cockburn Sarah N. , Boelio Lisa M. , Perlman Steve J.
Published: July 2010

Offsetting the Cost of Parasitism

Fruit flies, like most animals, are vulnerable to infection by a range of organisms, which, in co-infections, can interact with sometimes surprising effects.

Jaenike
et al.

(p.
212
) discovered that a species of
Spiroplasma
bacterium that is sometimes found in flies, and that is transmitted from mother to offspring, protects its host from the effects of a nematode worm parasite,
Howardula aoronymphium
. The worm sterilizes the female flies and shortens their lives, but when flies were experimentally infected with
Spiroplasma
, their fertility was rescued. Similarly, in wild populations of fruit flies infected with worms, those also infected with
Spiroplasma
had more eggs in their ovaries. The bacterium inhibits the growth of the adult female worms, but such is the advantage of this bacterial infection in offsetting the burden of nematodes on reproductive fitness,
Spiroplasma
appears to be spreading rapidly through populations of fruit flies in North America.
A Molecular Clock for Malaria Parasites
Authors: Ricklefs Robert E. , Outlaw Diana C.
Published: July 2010

Relative rates of nucleotide substitution between host and parasite cytochrome b set the molecular clock for malaria.
Step-Growth Polymerization of Inorganic Nanoparticles
Authors: Liu Kun , Nie Zhihong , Zhao Nana , Li Wei , Rubinstein Michael , Kumacheva Eugenia
Published: July 2010

Nanorod Polymers

Nanoparticles and colloids have been used to model crystallization and melting phenomena.

Liu
et al.

(p.
197
) studied the polymerization kinetics of nanoparticles. Functionalized arrowhead nanorods acted as linkable units that joined together in solvent-tuned assembly. The results resembled common processes of chemical polymerization: Growth was controlled kinetically and could be interpreted by formulas for step-growth polymerization and branching. Furthermore, some isomerization phenomena were observed, as was the formation of cyclic “macromolecules.”
Closing In on Models of Wall Turbulence
Authors: Adrian Ronald J.
Published: July 2010

Properties of turbulent flow near a wall, which creates drag resistance, can be predicted from the velocities in the nearby flow region.
Finding Fault in Fault Zones
Authors: Wang Kelin
Published: July 2010

The seismogenic behavior of subduction faults depends on the structural evolution of the fault zone.
Clearing Conformational Disease
Authors: Sifers Richard N.
Published: July 2010

Toxicity caused by aggregates of a misfolded protein is abolished with a drug that boosts cellular protein degradation mechanisms.
Farewell to Flatland
Authors: Service Robert F.
Published: July 2010

By creating electronic materials that bend and stretch, a pioneering researcher could change the way we light our homes, treat diseases, and power the planet.
HIV Moves In on Homeless Youth
Authors: Cohen Jon
Published: July 2010

Studies have discovered shockingly high HIV prevalence rates in kids who live on the streets of Russia and Ukraine; nongovernmental organizations are trying to give them new leases on life.
Reducing HIV Infection and Abandonment of Babies
Authors: Cohen Jon
Published: July 2010

Injecting drug users often seek medical help late in pregnancy and then relinquish their babies to the state. Surprisingly, their drug use is not the major factor.
Use of an Anti-Hepatitis C Virus (HCV) IgG Avidity Assay To Identify Recent HCV Infection
Authors: Gaudy-Graffin Catherine , Lesage Gérard , Kousignian Isabelle , Laperche Syria , Girault Annie , Dubois Frédéric , Goudeau Alain , Barin Francis
Published: July 2010

There is no reliable and simple diagnostic marker available to diagnose recent hepatitis C virus (HCV) infection. It has been shown that the avidity of specific IgG antibody is low in primary viral infection and increases with time. We report the development of an anti-HCV avidity assay derived from a commercially available test. A panel of 117 sera was first examined for IgG avidity. It was composed of samples from patients with recent (group 1,
n
= 14), chronic (group 2,
n
= 70), and resolved (group 3,
n
= 33) HCV infections. Avidity index (AI) values observed in recently infected patients were significantly lower (12.0% ± 9.2% [mean ± standard deviation]) than those found in chronic carriers (83.1% ± 15.2%). Using a threshold of 43.0%, this assay distinguished between groups 1 and 2 with very high sensitivity (98%) and specificity (100%). For group 3, a broader distribution of the AI values was observed (54.8% ± 27.3%), suggesting that this index would not be useful in HCV RNA-negative patients. Blind validation of the test was carried out with a panel of 36 serum samples from 17 HCV seroconverters. The assay described here is a useful tool to distinguish recent from chronic infection in HCV-viremic patients.
Limited Utility of Culture for
Mycoplasma pneumoniae
and
Chlamydophila pneumoniae
for Diagnosis of Respiratory Tract Infections
Authors: She Rosemary C. , Thurber Andy , Hymas Weston C. , Stevenson Jeffery , Langer Janine , Litwin Christine M. , Petti Cathy A.
Published: July 2010

We assessed the utility of culture for
Mycoplasma pneumoniae
and
Chlamydophila pneumoniae
to diagnose respiratory tract infections. Compared to PCR and IgM serology, culture was less sensitive and had extremely low yield. Culture is not recommended for these pathogens, and this method should be eliminated from routine practice.
Simultaneous Sequence Analysis of the 16S rRNA and
rpoB
Genes by Use of RipSeq Software To Identify
Mycobacterium
Species
Authors: Simmon Keith E. , Kommedal Øyvind , Saebo Øystein , Karlsen Bjarte , Petti Cathy A.
Published: July 2010

The 16S rRNA gene is commonly used to identify
Mycobacterium
spp., but alternative DNA targets can provide better resolution to the species level. We evaluated a novel system that enables simultaneous amplification, sequencing, and analysis of two different DNA targets in a single tube to identify clinical isolates of
Mycobacterium
spp. For 139 clinical isolates, we found that the 16S rRNA gene alone identified 67 (48%) isolates as single species, 68 (49%) isolates to the complex or group level, and 4 (3%) isolates to the genus level only. The
rpoB
gene alone identified 117 (84%) isolates as single species, 10 (7%) isolates to the complex or group level, and 12 (8%) isolates to the genus level only. Combining the separate analyses for sequencing of two gene targets, 119 (86%) isolates were identified as single species and 10 (7%) isolates were identified to the complex or group level. Seven (5%) isolates were identified as novel species within established groups, and 3 (2%) were identified to the genus level only. Dual-locus identification identified 110 (79%) isolates as single species and 22 (16%) isolates to the complex or group level. Six (4%) were identified as novel species within established groups, and 1 (1%) was identified to the genus level only. Identifications were more accurate when both the 16S rRNA and
rpoB
genes were screened, and reliance on a single gene target was suboptimal. RipSeq dual-locus software provides an accurate alternative method for laboratories using two different gene targets for microorganism identification.
Identification of Newly Described
Streptococcus pneumoniae
Serotype 6D by Use of the Quellung Reaction and PCR
Authors: Oftadeh Shahin , Satzke Catherine , Gilbert Gwendolyn L.
Published: July 2010

We tested 121 pneumococcal serogroup 6 isolates (including 30 serotype 6C and 24 serotype 6D isolates) by serotype-specific PCR and the Quellung reaction, using “old” and “new” pool B, factor 6b, and new factor 6d antisera. In combination with group B and other factor antisera, factor 6d antiserum can reliably identify the newly described serotype 6D.
Does a Feline Leukemia Virus Infection Pave the Way forBartonella henselaeInfection in Cats?
Authors: Buchmann Alexandra U. , Kershaw Olivia , Kempf Volkhard A. J. , Gruber Achim D.
Published: July 2010

Domestic cats serve as the reservoir hosts ofBartonella henselaeand may develop mild clinical symptoms or none after experimental infection. In humans,B. henselaeinfection can result in self-limiting cat scratch disease. However, immunocompromised patients may suffer from more-severe courses of infection or may even develop the potentially lethal disease bacillary angiomatosis. It was reasoned that cats with immunocompromising viral infections may react similarly toB. henselaeinfection. The aim of our study was to investigate the influence of the most important viruses known to cause immunosuppression in cats—Feline leukemia virus(FeLV),Feline immunodeficiency virus(FIV), andFeline panleukopenia virus(FPV)—on naturalB. henselaeinfection in cats. Accordingly, 142 cats from animal shelters were necropsied and tested forB. henselaeand concurrent infections with FeLV, FIV, or FPV by PCR and immunohistochemistry. A significant association was found betweenB. henselaeand FeLV infections (P= 0.00028), but not betweenB. henselaeand FIV (P= 1.0) or FPV (P= 0.756) infection, age (P= 0.392), or gender (P= 0.126). The results suggest that susceptibility toB. henselaeinfection is higher in cats with concurrent FeLV infections, regardless of whether the infection is latent or progressive. Histopathology and immunohistochemistry forB. henselaefailed to identify lesions that could be attributed specifically toB. henselaeinfection. We conclude that the course of naturalB. henselaeinfection in cats does not seem to be influenced by immunosuppressive viral infections in general but that latent FeLV infection may predispose cats toB. henselaeinfection or persistence.
Prevalence, Genetic Characteristics, and Zoonotic Potential of
Cryptosporidium
Species Causing Infections in Farm Rabbits in China
Authors: Shi Ke , Jian Fuchuan , Lv Chaochao , Ning Changshen , Zhang Longxian , Ren Xupeng , Dearen Theresa K. , Li Na , Qi Meng , Xiao Lihua
Published: July 2010

To assess the prevalence and public health significance of rabbit cryptosporidiosis, a total of 1,081 fecal specimens were collected between October 2007 and April 2008 from rabbits on eight farms in five different areas in Henan Province, China, and were examined by microscopy after Sheather's sucrose flotation and modified acid-fast staining. The average infection rate of
Cryptosporidium
was 3.4% (37/1,081 samples). There was a significant association between the prevalence of
Cryptosporidium
and the age of animals (χ
2
= 57.13;
P
< 0.01); the prevalence of cryptosporidiosis in 1- to 3-month-old rabbits was the highest (10.9%). The
Cryptosporidium
species in microscopy-positive specimens were genotyped by sequence analyses of the 18S rRNA, 70-kDa heat shock protein (HSP70), oocyst wall protein (COWP), and actin genes and were subtyped by sequence analysis of the 60-kDa glycoprotein (gp60) gene. Only the
Cryptosporidium
rabbit genotype was identified, with 100% sequence identity to published sequences of the 18S rRNA, HSP70, COWP, and actin genes, and the strains belonged to three gp60 subtypes (VbA36, VbA35, and VbA29). In view of the recent finding of the
Cryptosporidium
rabbit genotype in human outbreak and sporadic cases, the role of rabbits in the transmission of human cryptosporidiosis should be reassessed.
Corynebacterium falsenii
Bacteremia Occurring in an Infant on Vancomycin Therapy
Authors: Tam Pui-Ying Iroh , Fisher Mark A. , Miller Nancy S.
Published: July 2010

Corynebacterium falsenii
was described in 1998 as a new
Corynebacterium
species. We give the first detailed description of a clinically significant
Corynebacterium falsenii
bacteremia occurring in an infant while on vancomycin therapy.
Barriers to Intravenous Penicillin Use for Treatment of Nonmeningitis Pneumococcal Disease
Authors: Rosen Jennifer , Beekmann Susan , Polgreen Philip , Moore Matthew
Published: July 2010

Infectious disease physicians were surveyed to determine whether the new penicillin breakpoint change will translate into increased penicillin use and to identify barriers to intravenous (i.v.) penicillin use for pneumococcal infections. The inconvenience of i.v. penicillin may limit its use despite a reduction in numbers of infections considered resistant.
Laboratory Surveillance for Prospective Plasmid-Mediated AmpC β-Lactamases in the Kinki Region of Japan
Authors: Yamasaki Katsutoshi , Komatsu Masaru , Abe Noriyuki , Fukuda Saori , Miyamoto Yugo , Higuchi Takeshi , Ono Tamotsu , Nishio Hisaaki , Sueyoshi Noriyuki , Kida Kaneyuki , Satoh Kaori , Toyokawa Masahiro , Nishi Isao , Sakamoto Masako , Akagi Masahiro , Nakai Isako , Kofuku Tomomi , Orita Tamaki , Wada Yasunao , Jikimoto Takumi , Kinoshita Shohiro , Miyamoto Kazuaki , Hirai Itaru , Yamamoto Yoshimasa
Published: July 2010

Extended-spectrum β-lactamases, plasmid-mediated AmpC β-lactamases (PABLs), and plasmid-mediated metallo-β-lactamases confer resistance to many β-lactams. In Japan, although several reports exist on the prevalence of extended-spectrum β-lactamases and metallo-β-lactamases, the prevalence and characteristics of PABLs remain unknown. To investigate the production of PABLs, a total of 22,869 strains of 4 enterobacterial species,
Escherichia coli
,
Klebsiella pneumoniae
,
Klebsiella oxytoca
, and
Proteus mirabilis
, were collected during six 6-month periods from 17 clinical laboratories in the Kinki region of Japan. PABLs were detected in 29 (0.13%) of 22,869 isolates by the 3-dimensional test, PCR analysis, and DNA sequencing analysis. PABL-positive isolates were detected among isolates from 13 laboratories. Seventeen of 13,995 (0.12%)
E. coli
isolates, 8 of 5,970 (0.13%)
K. pneumoniae
isolates, 3 of 1,722 (0.17%)
K. oxytoca
isolates, and 1 of 1,182 (0.08%)
P. mirabilis
isolates were positive for PABLs. Of these 29 PABL-positive strains, 20 (69.0%), 6 (20.7%), 2 (6.9%), and 1 (3.4%) carried the genes for CMY-2, DHA-1, CMY-8, and MOX-1 PABLs, respectively. Pattern analysis of randomly amplified polymorphic DNA and pulsed-field gel electrophoretic analysis revealed that the prevalence of CMY-2-producing
E. coli
strains was not due to epidemic strains and that 3 DHA-1-producing
K. pneumoniae
strains were identical, suggesting their clonal relatedness. In conclusion, the DHA-1 PABLs were predominantly present in
K. pneumoniae
strains, but CMY-2 PABLs were predominantly present in
E. coli
strains. The present findings will provide significant information to assist in preventing the emergence and further spread of PABL-producing bacteria.
Equus caballus
Major Histocompatibility Complex Class I Is an Entry Receptor for Equine Herpesvirus Type 1
Authors: Kurtz Brian M. , Singletary Lauren B. , Kelly Sean D. , Frampton Arthur R.
Published: July 2010

In this study,
Equus caballus
major histocompatibility complex class I (MHC-I) was identified as a cellular entry receptor for the alphaherpesvirus equine herpesvirus type 1 (EHV-1). This novel EHV-1 receptor was discovered using a cDNA library from equine macrophages. cDNAs from this EHV-1-susceptible cell type were inserted into EHV-1-resistant B78H1 murine melanoma cells, these cells were infected with an EHV-1
lacZ
reporter virus, and cells that supported virus infection were identified by X-Gal (5-bromo-4-chloro-3-indolyl-β-
d
-galactopyranoside) staining. Positive cells were subjected to several rounds of purification to obtain homogeneous cell populations that were shown to be uniformly infected with EHV-1. cDNAs from these cell populations were amplified by PCR and then sequenced. The sequence data revealed that the EHV-1-susceptible cells had acquired an
E. caballus
MHC-I cDNA. Cell surface expression of this receptor was verified by confocal immunofluorescence microscopy. The MHC-I cDNA was cloned into a mammalian expression vector, and stable B78H1 cell lines were generated that express this receptor. These cell lines were susceptible to EHV-1 infection while the parental B78H1 cells remained resistant to infection. In addition, EHV-1 infection of the B78H1 MHC-I-expressing cell lines was inhibited in a dose-dependent manner by an anti-MHC-I antibody.
Release of Genotype 1 Hepatitis E Virus from Cultured Hepatoma and Polarized Intestinal Cells Depends on Open Reading Frame 3 Protein and Requires an Intact PXXP Motif
Authors: Emerson Suzanne U. , Nguyen Hanh T. , Torian Udana , Burke Danielle , Engle Ronald , Purcell Robert H.
Published: July 2010

Hepatitis E virus genotype 1 strain Sar55 replicated in subcloned Caco-2 intestinal cells and Huh7 hepatoma cells that had been transfected with
in vitro
transcribed viral genomes, and hepatitis E virions were released into the culture medium of both cell lines. Virus egress from cells depended on open reading frame 3 (ORF3) protein, and a proline-rich sequence in ORF3 was important for egress from cultured cells and for infection of macaques. Both intracellular ORF3 protein accumulation and virus release occurred at the apical membrane of polarized Caco-2 cells. ORF3 protein and lipids were intimately associated with virus particles produced in either cell line; ORF2 epitopes were masked in these particles and could not be immunoprecipitated with anti-ORF2.
JC Virus Latency in the Brain and Extraneural Organs of Patients with and without Progressive Multifocal Leukoencephalopathy
Authors: Tan Chen S. , Ellis Laura C. , Wüthrich Christian , Ngo Long , Broge Thomas A. , Saint-Aubyn Jenny , Miller Janice S. , Koralnik Igor J.
Published: July 2010

JC virus (JCV) is latent in the kidneys and lymphoid organs of healthy individuals, and its reactivation in the context of immunosuppression may lead to progressive multifocal leukoencephalopathy (PML). Whether JCV is present in the brains or other organs of healthy people and in immunosuppressed patients without PML has been a matter of debate. We detected JCV large T DNA by quantitative PCR of archival brain samples of 9/24 (38%) HIV-positive PML patients, 5/18 (28%) HIV-positive individuals, and 5/19 (26%) HIV-negative individuals. In the same samples, we detected JCV regulatory region DNA by nested PCR in 6/19 (32%) HIV-positive PML patients, 2/11 (18%) HIV-positive individuals, and 3/17 (18%) HIV-negative individuals. In addition, JCV DNA was detected in some spleen, lymph node, bone, and kidney samples from the same groups.
In situ
hybridization data confirmed the presence of JCV DNA in the brains of patients without PML. However, JCV proteins (VP1 or T antigen) were detected mainly in the brains of 23/24 HIV-positive PML patients, in only a few kidney samples of HIV-positive patients, with or without PML, and rarely in the bones of HIV-positive patients with PML. JCV proteins were not detected in the spleen or lymph nodes in any study group. Furthermore, analysis of the JCV regulatory region sequences showed both rearranged and archetype forms in brain and extraneural organs in all three study groups. Regulatory regions contained increased variations of rearrangements correlating with immunosuppression. These results provide evidence of JCV latency in the brain prior to severe immunosuppression and suggest new paradigms in JCV latency, compartmentalization, and reactivation.
7SL RNA Is Retained in HIV-1 Minimal Virus-Like Particles as an S-Domain Fragment
Authors: Keene Sarra E. , King Steven R. , Telesnitsky Alice
Published: July 2010

HIV-1 is known to package several small cellular RNAs in addition to its genome. Previous work consistently demonstrated that the host structural RNA 7SL is abundant in HIV-1 virions but has yielded conflicting results regarding whether 7SL is present in minimal, assembly-competent virus-like particles (VLPs). Here, we demonstrate that minimal HIV-1 VLPs retain 7SL RNA primarily as an endoribonucleolytic fragment, referred to as 7SL remnant (7SLrem). Nuclease mapping showed that 7SLrem is a 111-nucleotide internal portion of 7SL, with 5′ and 3′ ends corresponding to unpaired loops in the 7SL two-dimensional structure. Analysis of VLPs comprised of different subsets of Gag domains revealed that all NC-positive VLPs contained intact 7SL while the presence of 7SLrem correlated with the absence of the NC domain. Because 7SLrem, which maps to the 7SL S domain, was not detectable in infected cells, we propose a model whereby the species recruited to assembling VLPs is intact 7SL RNA, with 7SLrem produced by an endoribonuclease in the absence of NC. Since recruitment of 7SL RNA was a conserved feature of all tested minimal VLPs, our model further suggests that 7SL's recruitment is mediated, either directly or indirectly, through interactions with conserved features of all tested VLPs, such as the C-terminal domain of CA.
HIV Infection Upregulates Caveolin 1 Expression To Restrict Virus Production
Authors: Lin Shanshan , Wang Xiao Mei , Nadeau Peter E. , Mergia Ayalew
Published: July 2010

Caveolin 1 (Cav-1) is a major protein of a specific membrane lipid raft known as caveolae. Cav-1 interacts with the gp41 of the human immunodeficiency virus (HIV) envelope, but the role of Cav-1 in HIV replication and pathogenesis is not known. In this report, we demonstrate that HIV infection in primary human monocyte-derived macrophages (MDMs), THP-1 macrophages, and U87-CD4 cells results in a dramatic upregulation of Cav-1 expression mediated by HIV Tat. The activity of p53 is essential for Tat-induced Cav-1 expression, as our findings show enhanced phosphorylation of serine residues at amino acid positions 15 and 46 in the presence of Tat with a resulting Cav-1 upregulation. Furthermore, inhibition of p38 mitogen-activated protein kinase (MAPK) blocked phosphorylation of p53 in the presence of Tat. Infection studies of Cav-1-overexpressing cells reveal a significant reduction of HIV production. Taken together, these results suggest that HIV infection enhances the expression of Cav-1, which subsequently causes virus reduction, suggesting that Cav-1 may contribute to persistent infection in macrophages.
Evolutionary Dynamics and Temporal/Geographical Correlates of Recombination in the Human Enterovirus Echovirus Types 9, 11, and 30
Authors: McWilliam Leitch E. C. , Cabrerizo M. , Cardosa J. , Harvala H. , Ivanova O. E. , Kroes A. C. M. , Lukashev A. , Muir P. , Odoom J. , Roivainen M. , Susi P. , Trallero G. , Evans D. J. , Simmonds P.
Published: July 2010

The relationship between virus evolution and recombination in species B human enteroviruses was investigated through large-scale genetic analysis of echovirus type 9 (E9) and E11 isolates (
n
= 85 and 116) from 16 European, African, and Asian countries between 1995 and 2008. Cluster 1 E9 isolates and genotype D5 and A E11 isolates showed evidence of frequent recombination between the VP1 and 3Dpol regions, the latter falling into 23 (E9) and 43 (E11) clades interspersed phylogenetically with 46 3Dpol clades of E30 and with those of other species B serotypes. Remarkably, only 2 of the 112 3Dpol clades were shared by more than one serotype (E11 and E30), demonstrating an extremely large and genetically heterogeneous recombination pool of species B nonstructural-region variants. The likelihood of recombination increased with geographical separation and time, and both were correlated with VP1 divergence, whose substitution rates allowed recombination half-lives of 1.3, 9.8, and 3.1 years, respectively, for E9, E11, and E30 to be calculated. These marked differences in recombination dynamics matched epidemiological patterns of periodic epidemic cycles of 2 to 3 (E9) and 5 to 6 (E30) years and the longer-term endemic pattern of E11 infections. Phylotemporal analysis using a Bayesian Markov chain Monte Carlo method, which placed recombination events within the evolutionary reconstruction of VP1, showed a close relationship with VP1 lineage expansion, with defined recombination events that correlated with their epidemiological periodicity. Whether recombination events contribute directly to changes in transmissibility that drive epidemic behavior or occur stochastically during periodic population bottlenecks is an unresolved issue vital to future understanding of enterovirus molecular epidemiology and pathogenesis.
Baculovirus
Per Os
Infectivity Factors Form a Complex on the Surface of Occlusion-Derived Virus
Authors: Peng Ke , van Oers Monique M. , Hu Zhihong , van Lent Jan W. M. , Vlak Just M.
Published: July 2010

Five highly conserved
per os
infectivity factors, PIF1, PIF2, PIF3, PIF4, and P74, have been reported to be essential for oral infectivity of baculovirus occlusion-derived virus (ODV) in insect larvae. Three of these proteins, P74, PIF1, and PIF2, were thought to function in virus binding to insect midgut cells. In this paper evidence is provided that PIF1, PIF2, and PIF3 form a stable complex on the surface of ODV particles of the baculovirus
Autographa californica
multinucleocapsid nucleopolyhedrovirus (AcMNPV). The complex could withstand 2% SDS-5% β-mercaptoethanol with heating at 50°C for 5 min. The complex was not formed when any of the genes for PIF1, PIF2, or PIF3 was deleted, while reinsertion of these genes into AcMNPV restored the complex. Coimmunoprecipitation analysis independently confirmed the interactions of the three PIF proteins and revealed in addition that P74 is also associated with this complex. However, deletion of the
p74
gene did not affect formation of the PIF1-PIF2-PIF3 complex. Electron microscopy analysis showed that PIF1 and PIF2 are localized on the surface of the ODV with a scattered distribution. This distribution did not change for PIF1 or PIF2 when the gene for PIF2 or PIF1 protein was deleted. We propose that PIF1, PIF2, PIF3, and P74 form an evolutionarily conserved complex on the ODV surface, which has an essential function in the initial stages of baculovirus oral infection.
Characterization of the Alpha Interferon-Induced Postentry Block to HIV-1 Infection in Primary Human Macrophages and T Cells
Authors: Goujon Caroline , Malim Michael H.
Published: July 2010

Type I interferon (IFN) inhibits virus replication by activating multiple antiviral mechanisms and pathways. It has long been recognized that alpha interferon (IFN-α) can potently block both early and late stages of HIV-1 replication. The mechanistic basis for the early block(s) to infection is unknown, as is the identity of the participating antiviral factor(s). Here, we define the effect(s) of IFN-α on HIV-1 infection of primary human macrophages and CD4+T cells, as well as several monocytic and T-cell lines. We demonstrate that IFN-α treatment of macrophages, THP-1 cells, and, to a lesser extent, primary CD4+T cells markedly inhibits infection, whereas the effects are minimal in CD4+T-cell lines. Virus entry is essentially unaffected by IFN-α, but substantial decreases (sometimes >99%) in nascent cDNA accumulation correlate closely with losses in infectivity. Interestingly, proteasome inhibitors rescue viral cDNA accumulation, revealing a link between the ubiquitin-proteasome system and IFN-α-induced viral restriction. We also found that diverse primate and nonprimate retroviruses were susceptible to suppression by IFN-α. Importantly, all the primary and immortalized cells used here are proficient at responding to IFN-α, as judged by the induced expression of numerous IFN-stimulated genes, includingPKRandOAS1, indicating that a general deficiency in IFN-α responsiveness does not underlie IFN-α's inability to elicit an antiviral state in CD4+T-cell lines. Rather, we speculate that IFN-α fails to induce antiretroviral factors in these cells and that comparative transcriptional profiling with responsive cells, such as macrophages, invokes a strategy for identifying new host-encoded antiviral effectors.