bluuebunny/crossref_metadata_2025 huggingface dataset:
Viability Study of Retrieving the Evaporated Water in a Mechanical Draft Cross Flow Cooling Tower
Authors: Zimmermann Rafael , Mantelli Marcia B. H. , Borges Thomaz P. F. , Costa Camilo A. S.
Published: March 2011

Cooling towers use evaporative heat transfer to reduce process water temperature. In mostly cases, the amount of water lost to evaporation is irrelevant, but in the present case of study, the amount of makeup water due to evaporation, is around 700 m3/h. That alone is a considerable amount of fresh water that needs to be removed from the local rivers and is currently having a negative impact in the fresh water availability for consumption. This study explores viable solutions to recover some of the evaporated water, but not compromising the effectiveness of the cooling tower. The plant is located in the southeast region of Brazil where temperature and humidity vary considerably along the year. The present study focuses on retrieving the evaporated water through condensation and capturing fog without compromising the cooling tower performance. Data from the actual cooling tower was used in the thermodynamic analysis. Computational fluid dynamics (CFD) was used to simulate the mixing of air leaving the cooling tower with outdoor air. An experimental setup is also being developed to reproduce the condensation process.
Effects of Fin Configuration on Heat Transfer Rate in Packed Bed Reactors for Improvement of Their Thermal Characteristics
Authors: Nakaso Koichi , Aoki Takuro , Fukai Jun
Published: March 2011

Packed bed reactors are utilized for catalysts, chemical heat pumps, etc. Because the effective thermal conductivities of the packed beds of particles are generally low (≈10−1 W/mK), this matter often results in low performance and degradation of catalyst. Many heat transfer tubes with fins and/or much filler with high thermal conductivities are inserted in the packed bed reactors to improve heat transfer rate. In return to this, the volume of reactive particles packed into the reactors, or stored energy, decreases. In this study, the effect of fin configurations on the heat transfer rate in the reactors is numerically investigated. Three configurations of fins are studied. (1) “Sheet type” is a longitudinal fin attached on the heat transfer tubes. It is placed to connect between heat transfer tubes. (2) “Straight type” is several longitudinal fins in the half length of the tube pitch attached on the tube with radial structure. (3) “Spiral type” is many narrow rectangular fins attached on the tube with spiral structure. To discuss the effect of fin configuration on the heat transfer generally, the heat conduction equation in the packed bed around the tube is converted to the dimensionless form. The transient temperature responses in the packed bed and fins at a uniform temperature are calculated when the temperature of the tube surface is stepwise changes. In another analytical system, a homogeneous body around the tube is assumed. To evaluate the thermal performance of the fin, apparent thermal conductivity is defined as the thermal conductivity which gives the same thermal response as that calculated in the heterogeneous system. As a result, the spiral type rather than the straight and sheet types effectively increases apparent thermal conductivity. The apparent thermal conductivity of the spiral type is two-three times larger than the straight type, and ten times as large as the sheet type. This result indicates dispersion of fins in packed bed is essential to improve the thermal response in the reactors.
Measurement of Liquid Film Thickness in Micro Tube Annular Flow
Authors: Kanno Hiroshi , Han Youngbae , Saito Yusuke , Shikazono Naoki
Published: March 2011

Heat transfer in micro scale two-phase flow attracts large attention since it can achieve large heat transfer area per density. At high quality, annular flow becomes one of the major flow regimes in micro two-phase flow. Heat is transferred by evaporation or condensation of the liquid film, which are the dominant mechanisms of micro scale heat transfer. Therefore, liquid film thickness is one of the most important parameters in modeling the phenomena. In macro tubes, large numbers of researches have been conducted to investigate the liquid film thickness. However, in micro tubes, quantitative information for the annular liquid film thickness is still limited. In the present study, annular liquid film thickness is measured using a confocal method, which is used in the previous study [1, 2]. Glass tubes with inner diameters of 0.3, 0.5 and 1.0 mm are used. Degassed water and FC40 are used as working fluids, and the total mass flux is varied from G = 100 to 500 kg/m2s. Liquid film thickness is measured by laser confocal displacement meter (LCDM), and the liquid-gas interface profile is observed by a high-speed camera. Mean liquid film thickness is then plotted against quality for different flow rates and tube diameters. Mean thickness data is compared with the smooth annular film model of Revellin et al. [3]. Annular film model predictions overestimated the experimental values especially at low quality. It is considered that this overestimation is attributed to the disturbances caused by the interface ripples.
Virtual Reality Visualization of CFD Simulation for Iron/Steelmaking Processes
Authors: Fu Dong , Wu Bin , Chen Guoheng , Moreland John , Tian Fengguo , Hu Yuzhu , Zhou Chenn Q.
Published: March 2011

Computational Fluid Dynamics (CFD) has become a powerful simulation technology used in iron/steelmaking industrial applications for process design and optimization to save energy. In this paper, a Virtual Engineering (VE) application is presented that uses Virtual Reality (VR) to visualize CFD results in a tracked immersive projection system. The interactive Virtual Reality (VR) was specifically adapted for CFD post-processing to better understand CFD results and more efficiently communicate with non-CFD experts. The VE application has been utilized to make an assessment in terms of visualization and optimization for steelmaking furnaces. The immersive system makes it possible to gain a quick, intuitive understanding of the flow characteristics and distributions of pressure, temperature, and species properties in the industrial equipment. By introducing the virtual engineering environment, the value of CFD simulations has been greatly enhanced to allow engineers to gain much needed process insights for the design and optimization of industrial processes.
Heat Transfer During Drop Impact Onto a Heated Solid Substrate
Authors: Moita A. S. , Moreira A. L. N. , Roisman Ilia V.
Published: March 2011

The present paper addresses the theoretical and experimental study of a liquid drop impacting onto a solid heated substrate. The experiments encompass the measurement and evaluation of the instantaneous substrate and contact temperatures, for different impact conditions and various thermodynamic properties of the liquid and target. Initial surface temperatures are varied from the ambient temperature up to slightly above the boiling temperature of the liquids (TW0max = 120°C), for different surface materials, covering significantly different wall effusivities, thus allowing to validate the model for extreme conditions. The theory is based on the remote self-similar analytical solution of the Navier-Stokes equations in the spreading drop coupled with the energy equation, which allows obtaining a theoretical solution for the flow field and temperature field in the liquid region. An explicit analytical expression is proposed for the contact temperature, which is expressed, not only through the thermal effusivities of the solid and liquid materials and their initial temperature, but also depends on the Prandtl number. The theory predicts a constant value of the contact temperature in the phase when the thermal boundary layer is thinner than the thickness of the lamella. The model is validated by comparison with the experimental data. The agreement is rather good despite the fact that no adjustable parameters are introduced in the model.
Modelling of the Thermal Radiative Properties of Oxide Ceramics
Authors: Rousseau Benoit , del Campo Leire , Rolland Julien-Yves , de Sousa Meneses Domingos , Echegut Patrick
Published: March 2011

A numerical model based upon a Monte Carlo Ray Tracing (MCRT) code was developed to predict the thermal radiative properties (reflectance, transmittance, emittance) of a family of virtual alumina ceramics with prescribed textural features. The numerical samples were constituted of polydisperse spherical pores [20–120 μm] embedded in a continuous and homogenous alumina matrix. The texture of the alumina ceramics were numerically settled, allowing, in our case, to fix their porosity, their volumetric surface and their radii size distribution. The MCRT code was applied at T = 300 K and T = 1300 K since, at the local scale, the complex indices of refraction of the alumina matrix were known. The comparisons of the emittance spectra of the numerical samples with the ones acquired by infrared emittance spectroscopy on a single crystal of alumina (T = 300 K and T = 1300 K) allow to discuss the effects played by the temperature and by each textural parameters.
New Implementations of Surface Tension Forces for PLIC-VOF Methods
Authors: Castro Jesu´s , Oliva Assensi , Garci´a-Rivera Eduardo
Published: March 2011

A comparative study has been carried out between different models of implementing surface tension for PLIC-VOF methods: i) the well known Continuum Surface Force (CSF); ii) Staggered Grid Interface Pressure (SGIP); iii) Modified Meier’s. As main difference with respect the CSF model, the two last use information of the interface location for the calculation of the surface tension forces, therefore, they need a model of interface reconstruction. The models will be tested under static and dynamic conditions, for the case of a drop and bubble between water and air. In order to reduce the ‘parasitic’ currents that is characteristic of this type of models, two different strategies are used: i) a new method for the calculation of the interface curvature based on the use of polar coordinates; ii) the use of kernels for smoothing the jump of the colour function and the interface. Additionally, the influence of the order of accuracy of the reconstruction algorithms employed that affect the curvature estimation and the surface tension force calculation is also checked. After testing the different cases, it can be concluded that SGIP and modified Meier perform in a comparable way, and much better than CSF model without kernel, that is only competitive with the use of the kernels. However, modified Meier is preferred respect SGIP due to its straitghforward implementation on unstructured meshes.
Large Scale Hydrogen Production From Nuclear Energy Using High Temperature Electrolysis
Authors: O’Brien James E.
Published: March 2011

Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.
Control of Turbulent Transport: Less Friction and More Heat Transfer
Authors: Kasagi Nobuhide , Hasegawa Yosuke , Fukagata Koji , Iwamoto Kaoru
Published: March 2011

Because of the importance of fundamental knowledge on turbulent heat transfer for further decreasing entropy production and improving efficiency in various thermo-fluid systems, we revisit a classical issue whether enhancing heat transfer is possible with skin friction reduced or at least not increased as much as heat transfer. The answer that numerous previous studies suggest is quite pessimistic because the analogy concept of momentum and heat transport holds well in a wide range of flows. Nevertheless, the recent progress in analyzing turbulence mechanics and designing turbulence control offers a chance to develop a scheme for dissimilar momentum and heat transport. By reexamining the governing equations and boundary conditions for convective heat transfer, the basic strategies for achieving dissimilar control in turbulent flow is generally classified into two groups, i.e., one for the averaged quantities and the other for the turbulent fluctuating components. As a result, two different approaches are discussed presently. First, under three typical heating conditions, the contribution of turbulent transport to wall friction and heat transfer is mathematically formulated, and it is shown that the difference in how the local turbulent transport of momentum and that of heat contribute to the friction and heat transfer coefficients is a key to answer whether the dissimilar control is feasible. Such control is likely to be achieved when the weight distributions for the stress and flux in the derived relationships are different. Secondly, we introduce a more general methodology, i.e., the optimal control theory. The Fre´chet differentials obtained clearly show that the responses of velocity and scalar fields to a given control input are quite different due to the fact that the velocity is a divergence-free vector while the temperature is a conservative scalar. By exploiting this inherent difference, the dissimilar control can be achieved even in flows where the averaged momentum and heat transport equations have the same form.
Space Experiment of Marangoni Convection on International Space Station
Authors: Kawamura Hiroshi , Nishino Koichi , Matsumoto Satoshi , Ueno Ichiro
Published: March 2011

This paper reports some important results obtained from a series of microgravity experiments on the Marangoni convection that takes place in liquid bridges. This project, called Marangoni Experiment in Space (MEIS), started from August 22, 2008 as the first science experiment on the Japanese Experimental Module “KIBO” at the ISS. Two series of experiments, MEIS-1 and 2, were conducted in 2008 and 2009, respectively. The experimental methods used are explained in some detail. The maximum size of the liquid bridge that could be realized during these experiments was 30 mm in diameter and 60 mm in length, giving an aspect ratio of 2.0. The results are obtained for a wide range of aspect ratios of the liquid bridges, including the values that cannot be reached in 1g experiments, and therefore, they provide indispensable amount of data for the study of instability mechanisms of the Marangoni convection.
The Role of Entropy Generation in Momentum and Heat Transfer
Authors: Herwig Heinz
Published: March 2011

Entropy generation in a velocity and temperature field is shown to be very significant in momentum and heat transfer problems. After the determination of this post-processing quantity many details about the physics of a problem are available. This second law analysis (SLA) is a tool for conceptual considerations, for the determination of losses, both in the velocity and the temperature field, and it helps to assess complex convective heat transfer processes. These three aspects in conjunction with entropy generation are discussed in detail and illustrated by several examples.
Direct Waste Heat Utilization From Liquid-Cooled Supercomputers
Authors: Brunschwiler Thomas , Meijer Gerhard Ingmar , Paredes Stephan , Escher Werner , Michel Bruno
Published: March 2011

Chip microscale liquid-cooling reduces conductive and convective resistance thereby improving the efficiency of datacenters by allowing coolant temperatures above the free cooling limit in all climates. This eliminates the need for chillers and allows the thermal energy to be re-used in cold climates. Replacing the combustion processes for secondary users with recycled heat from the datacenter effectively eliminates carbon dioxide emission during the winter season and reduces operating cost throughout the year. The energy balance of emission-reduced datacenters is compared with a classical air cooled datacenter, a datacenter with free cooling in a cold climate zone, and a datacenter with chiller-mediated energy re-use. Hot water cooled datacenters reduce the effective energy cost by almost a factor of two compared to a current datacenter and reduce the carbon footprint by an even larger factor. Our energy re-use concept has been demonstrated in terms of cost and energy savings in a 60°C liquid cooled supercomputer. Additional alternative energy re-use schemes in hot climates for desalination and adsorption cooling allow close to full use of datacenter heat in all climates and all seasons. Output temperatures for these applications compared to space heating need to be 10–20°C higher which becomes possible through hotspot adapted cooling that eliminates mixing of fluids with different temperatures. In addition, interlayer cooled chip stacks allow double sided hotspot optimized cooling even closer to the heat source with low flow rates and low pumping power. This improves the large efficiency gain that becomes possible through 3D chip stacking.
Reduced Order Thermal Models of Multi-Scale Microsystems
Authors: Joshi Yogendra
Published: March 2011

Thermal systems often involve multiple spatial and temporal scales, where transport information from one scale is relevant at others. Optimized thermal design of such systems and their control require approaches for their rapid simulation. These activities are of increasing significance due to the need for energy efficiency in the operation of these systems. Traditional full-field simulation methodologies are typically unable to resolve these scales in a computationally efficient manner. We handle the simulations of conjugate transport processes over selected length scales of interest via reduced order modeling through approaches such as compact finite elements, and proper orthogonal decomposition. In order to incorporate the influence of length scales beyond these, lumped models are invoked, with appropriate handshaking between the two frameworks. We illustrate the methodology through selected examples, with a focus on information technology systems.
Heat Transfer Design in Adsorption Refrigeration Systems for Efficient Use of Low Grade Thermal Energy
Authors: Wang R. Z. , Xia Z. Z. , Wang L. W. , Lu Z. S. , Li S. L. , Li T. X. , Wu J. Y. , He S.
Published: March 2011

Adsorption refrigeration and heat pump systems have been considered as very important means for the efficient use of low grade thermal energy in the temperature range of 60–150°C. Sorption systems are merely heat exchanger based thermodynamic systems, and therefore a good design to optimize heat and mass transfer with reaction or sorption processes is very important for high performance of the systems. Studies on heat and mass transfer enhancement in adsorption beds have been done extensively. Notable techniques is whereby the adsorbent bed is fitted with finned heat exchanger embedded with adsorbent particles, or the adsorbent particles may be compressed and solidified and then coupled with finned tube or plate heat exchangers. The use of expanded graphite seems to be an effective method to improve both heat and mass transfer in the reaction bed. Studies have also shows the need to enhance the heat transfer in adsorption bed to match with the heat transfer of thermal fluids. Use of heat pipes and good thermal loop design could yield higher thermal performances of a sorption system, when coupled with adsorption beds to provide heating and cooling to the beds. A novel design with passive evaporation, known as rising film evaporation coupled with a gravity heat pipe was introduced for high cooling output. It has also been shown that heat and mass recovery in the internal sorption systems is critical, and novel arrangement of thermal fluid and refrigerant may result in high performance sorption systems. Based upon the above researches, various sorption systems have been developed, and high efficient performances have been reached. Typical sorption systems include (1) A silica gel-water adsorption water chillier with a COP about 0.55 when powered with 80°C hot water, (2) A CaCl2-ammonia adsorption refrigerator with a COP over 0.3 at −20 °C when powered with 120 °C water vapor, which has a specific cooling power about 600 W/kg-adsorbent. The above mentioned systems have shown that solid sorption systems have become market potential products, and low grade thermal energy, which is usually considered as waste heat, could be utilized to provide high grade cooling. This paper gives details of high efficient solid sorption systems recently developed, their heat transfer design, thermodynamic system coupling, and performance test results. Some examples of low grade thermal powered cooling systems are also presented.
Investigation of Duration-Dependent Multifactoring During Boiling on Down-Facing Heating Surface
Authors: Shekriladze Irakli G. , Gigineishvili Giorgi I. , Rusishvili Jondo G. , Shekriladze David I.
Published: March 2011

A model of the “theatre of director” (MTD) links dependence of developed boiling HTC only on two external parameters (heat flux and average effective radius of active nucleation sites) to short duration of each action of cooling mechanisms. According multifactoring concept (MFC) significant prolongation of the actions of cooling mechanisms leads to transition to specific regimes with dependence on increased number of factors (duration-dependent multifactoring (DDM)). Splitting of developed boiling heat transfer curve into several curves, depending on sublooling of bulk liquid, direction of gravity field and thermal parameters of heating surface, has been fixed through experimental study of DDM of pool boiling heat transfer on downward-facing horizontal heating surface. Interpretation and qualitative analysis of received experimental data on HTC and video-films of characteristic boiling regimes allow to arriving at the conclusion about applicability of unified consistent research framework MTD-MFC in terms of description of diversity of boiling heat transfer curves.
Field electron emission properties of n-type (111)-oriented single crystal cubic boron nitride
Authors: Yamada Takatoshi , Nebel Christoph E. , Taniguchi Takashi
Published: March 2011

The authors report the field emission properties of (111)-oriented single crystal n-type semiconducting cubic boron nitride (c-BN). Specifically, c-BN with two different surface conditions was prepared and analyzed. One surface was hydrogen (H) terminated and has negative electron affinity (NEA). The second surface was obtained by annealing in vacuum and has positive electron affinity (PEA). Field emission properties of carbon-reconstructed n-type semiconducting single crystal diamond were also characterized for comparison. The vacuum annealed c-BN surface with PEA showed low threshold voltages compared to the H-terminated NEA surfaces. The internal barrier height of the NEA c-BN surface was estimated to be 3.5 eV, in accordance with the Schottky barrier-lowering model. This internal barrier prevents electrons from approaching the surface. Thus, a higher electric field is required to reduce the internal barrier for field emission. From the Fowler–Nordheim plots, positive electron affinity of vacuum annealed surface was 0.6–0.8 eV, which dominates field emission from vacuum annealed c-BN surface.
Quantum mechanics of a free particle from properties of the Dirac delta function
Authors: Bondar Denys I. , Lompay Robert R. , Liu Wing-Ki
Published: March 2011

Based on the assumption that the probability density of finding a free particle is independent of position, we infer the form of the eigenfunction for the free particle, ⟨x|p⟩=exp(ipx/ℏ)/2πℏ. The canonical commutation relation between the momentum and position operators and the Ehrenfest theorem in the free particle case are derived solely from differentiation of the delta function and the form of ⟨x|p⟩.
Instability of a constrained pendulum system
Authors: Ramachandran Prashanth , Krishna Srinivas Gopal , Ram Y. M.
Published: March 2011

Linear perturbation analysis is used to determine the natural frequency of two pendulums connected by a rod. The analysis indicates a zone of instability in what looks like a stable system. The paradoxical phenomenon is explained, and a simple experiment confirms the instability.
Demonstration of negative refraction of microwaves
Authors: Velazquez-Ahumada Maria C. , Freire Manuel J. , Algarin Jose M. , Marques Ricardo
Published: March 2011

An experimental setup to demonstrate negative refraction is described. A simple method for designing and fabricating a metamaterial with negative refractive index at microwave frequencies is discussed. The metamaterial is made of a multilayer planar arrangement of flat unit cells. A prism was fabricated and used to demonstrate negative refraction at the prism-air interface. The prism is designed for demonstrations and works at the frequency of commercial microwave transmitters and receivers.
Acoustic scattering from a spherical lens irradiated by a finite transducer: Focusing effect and refraction
Authors: Parrales Borrero Miguel A. , Pérez-Saborid Miguel , Fernández García Juan M.
Published: March 2011

We carry out a spatio-temporal analysis of the scattering from a spherical inhomogeneity irradiated by a finite transducer. We show that when the inhomogeneity behaves as a focusing acoustic lens, the gain and position of the focus depend strongly on the ratio of the lens size to the irradiation width. We also analyze the refraction through the lens which takes place for off-axis incidence using a two-dimensional approach. The results of the wave formulation reproduce those predicted by the law of refraction for the behavior of a ray and for the trajectory of a wave packet.
Susceptibility of 186 Nocardia sp. Isolates to 20 Antimicrobial Agents
Authors: Larruskain Julián , Idigoras Pedro , Marimón José M. , Pérez-Trallero Emilio
Published: March 2011

This study determined the antimicrobial susceptibilities of 186 clinical isolates of
Nocardia
spp. isolated in Gipuzkoa, northern Spain, between 1998 and 2009. Most isolates were recovered from respiratory samples,
Nocardia nova
,
N. farcinica
,
N. cyriacigeorgica
,
N. abscessus
, and
N. carnea
being the species most frequently isolated. Linezolid and amikacin were the only two antimicrobials to which all isolates were susceptible. The majority of
N. flavorosea
,
N. carnea
, and
N. farcinica
isolates were trimethoprim-sulfamethoxazole resistant.
The HIV Protease Inhibitor Nelfinavir Inhibits Kaposi's Sarcoma-Associated Herpesvirus Replication In Vitro
Authors: Gantt Soren , Carlsson Jacquelyn , Ikoma Minako , Gachelet Eliora , Gray Matthew , Geballe Adam P. , Corey Lawrence , Casper Corey , Lagunoff Michael , Vieira Jeffrey
Published: March 2011

Kaposi's sarcoma (KS) is the most common HIV-associated cancer worldwide and is associated with high levels of morbidity and mortality in some regions. Antiretroviral (ARV) combination regimens have had mixed results for KS progression and resolution. Anecdotal case reports suggest that protease inhibitors (PIs) may have effects against KS that are independent of their effect on HIV infection. As such, we evaluated whether PIs or other ARVs directly inhibit replication of Kaposi's sarcoma-associated herpesvirus (KSHV), the gammaherpesvirus that causes KS. Among a broad panel of ARVs tested, only the PI nelfinavir consistently displayed potent inhibitory activity against KSHV
in vitro
as demonstrated by an efficient quantitative assay for infectious KSHV using a recombinant virus, rKSHV.294, which expresses the secreted alkaline phosphatase. This inhibitory activity of nelfinavir against KSHV replication was confirmed using virus derived from a second primary effusion lymphoma cell line. Nelfinavir was similarly found to inhibit
in vitro
replication of an alphaherpesvirus (herpes simplex virus) and a betaherpesvirus (human cytomegalovirus). No activity was observed with nelfinavir against vaccinia virus or adenovirus. Nelfinavir may provide unique benefits for the prevention or treatment of HIV-associated KS and potentially other human herpesviruses by direct inhibition of replication.
Systemic Absorption of Rifamycin SV MMX Administered as Modified-Release Tablets in Healthy Volunteers
Authors: Di Stefano A. F. D. , Rusca A. , Loprete L. , Dröge M. J. , Moro L. , Assandri A.
Published: March 2011

The new oral 200-mg rifamycin SV MMX modified-release tablets, designed to deliver rifamycin SV directly into the colonic lumen, offer considerable advantages over the existing immediate-release antidiarrheic formulations. In two pharmacokinetics studies of healthy volunteers, the absorption, urinary excretion, and fecal elimination of rifamycin SV after single- and multiple-dose regimens of the new formulation were investigated. Concentrations in plasma of >2 ng/ml were infrequently and randomly quantifiable after single and multiple oral doses. The systemic exposure to rifamycin SV after single and multiple oral doses of MMX tablets under fasting and fed conditions or following a four-times-a-day (q.i.d.) or a twice-a-day (b.i.d.) regimen could be considered negligible. With both oral regimens, the drug was confirmed to be very poorly absorbable systemically. The amount of systemically absorbed antibiotic excreted by the renal route is far lower than 0.01% of the administered dose after both the single- and multiple-dose regimens. The absolute bioavailability, calculated as the mean percent ratio between total urinary excretion amounts (ΣXu) after a single intravenous injection and after a single oral dose under fasting conditions, was 0.0410 ± 0.0617. The total elimination of the unchanged rifamycin SV with feces was 87% of the administered oral dose. No significant effect of rifamycin SV on vital signs, electrocardiograms, or laboratory parameters was observed.
Antimicrobial Susceptibilities and Serotypes of Streptococcus pneumoniae Isolates from Elderly Patients with Pneumonia and Acute Exacerbation of Chronic Obstructive Pulmonary Disease
Authors: Pérez-Trallero Emilio , Marimón José M. , Larruskain Julián , Alonso Marta , Ercibengoa María
Published: March 2011

In the elderly,
Streptococcus pneumoniae
is the most common cause of pneumonia and one of the most frequently isolated pathogens in cases of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study was conducted to compare the pneumococcal isolates obtained during episodes of AECOPD and pneumonia in patients of ≥65 years old and to analyze whether in patients with AECOPD and pneumonia within a short interval, the same isolate caused both episodes. This laboratory-based study was performed between 2005 and 2008. Pneumococcal isolates from episodes of pneumonia (
n
= 401) and AECOPD (
n
= 398), matched one-to-one by date of isolation, were characterized. The serotypes and genotypes of other pneumococcal isolates causing pneumonia and AECOPD in the same patient were compared. In patients with pneumonia, COPD as an underlying disease was not associated with more-drug-resistant pneumococci. In contrast, isolates causing AECOPD showed higher rates of resistance than those causing pneumonia. Serotypes 1, 3, and 7F were more frequent in pneumonia. The same pneumococcus was involved in 25.7% (9/35 patients) of patients with two consecutive AECOPD episodes but in only 6.3% (2/32 patients) of COPD patients with pneumonia and exacerbation (Fisher's exact test;
P
= 0.047). Less invasive serotypes were isolated more often in AECOPD and were more resistant to antimicrobials. The presence of a specific pneumococcal serotype in AECOPD does not predict the etiology of subsequent pneumonia.
Pharmacokinetics of Anidulafungin in Pleural Fluid during the Treatment of a Patient with Candida Empyema
Authors: Moriyama Brad , Ditullio Marisa , Wilson Eleanor , Henning Stacey A. , Penzak Scott R. , Danner Robert L. , Pennick Gennethel , Rinaldi Michael G. , Zelazny Adrian M. , Gea-Banacloche Juan , Barrett A. John , Walsh Thomas J.
Published: March 2011

Candida
empyema is a serious complication of disseminated candidiasis. However, little is known about the intrapleural pharmacokinetics of echinocandins. We report the penetration of anidulafungin into the pleural fluid of a patient with
Candida tropicalis
empyema. The anidulafungin ratio for the area under the concentration-time curve from 0 h to the last measurement between pleural fluid and serum values was only 0.125 (12.5%), with pleural fluid concentrations ranging between 0.67 and 0.88 μg/ml.
PME-1, an Extended-Spectrum β-Lactamase Identified in Pseudomonas aeruginosa
Authors: Tian Guo-Bao , Adams-Haduch Jennifer M. , Bogdanovich Tatiana , Wang Hong-Ning , Doi Yohei
Published: March 2011

A novel extended-spectrum β-lactamase (ESBL) was identified in a
Pseudomonas aeruginosa
clinical isolate obtained from a patient admitted to a hospital in Pennsylvania in 2008. The patient had a prolonged hospitalization in a hospital in Dubai, United Arab Emirates, before being transferred to the United States. The novel ESBL, designated PME-1 (

P

seudo

m

onas aeruginosa
E
SBL 1), is a molecular class A, Bush-Jacoby-Medeiros group 2be enzyme and shared 50, 43, and 41% amino acid identity with the L2 β-lactamase of
Stenotrophomonas maltophilia
, CTX-M-9, and KPC-2, respectively. PME-1 conferred clinically relevant resistance to ceftazidime, cefotaxime, cefepime, and aztreonam in
P. aeruginosa
PAO1 but not to carbapenems. Purified PME-1 showed good hydrolytic activity against ceftazidime, cefotaxime, and aztreonam, while activity against carbapenems and cefepime could not be measured. PME-1 was inhibited well by β-lactamase inhibitors, including clavulanic acid, sulbactam, and tazobactam. The
bla
PME-1
gene was carried by an approximately 9-kb plasmid and flanked by tandem IS
CR24
elements.
Use of a Selective Inhibitor To Define the Chemotherapeutic Potential of the Plasmodial Hexose Transporter in Different Stages of the Parasite's Life Cycle
Authors: Slavic Ksenija , Delves Michael J. , Prudêncio Miguel , Talman Arthur M. , Straschil Ursula , Derbyshire Elvira T. , Xu Zhengyao , Sinden Robert E. , Mota Maria M. , Morin Christophe , Tewari Rita , Krishna Sanjeev , Staines Henry M.
Published: March 2011

During blood infection, malarial parasites use
d
-glucose as their main energy source. The
Plasmodium falciparum
hexose transporter (PfHT), which mediates the uptake of
d
-glucose into parasites, is essential for survival of asexual blood-stage parasites. Recently, genetic studies in the rodent malaria model,
Plasmodium berghei
, found that the orthologous hexose transporter (PbHT) is expressed throughout the parasite's development within the mosquito vector, in addition to being essential during intraerythrocytic development. Here, using a
d
-glucose-derived specific inhibitor of plasmodial hexose transporters, compound 3361, we have investigated the importance of
d
-glucose uptake during liver and transmission stages of
P. berghei
. Initially, we confirmed the expression of PbHT during liver stage development, using a green fluorescent protein (GFP) tagging strategy. Compound 3361 inhibited liver-stage parasite development, with a 50% inhibitory concentration (IC
50
) of 11 μM. This process was insensitive to the external
d
-glucose concentration. In addition, compound 3361 inhibited ookinete development and microgametogenesis, with IC
50
s in the region of 250 μM (the latter in a
d
-glucose-sensitive manner). Consistent with our findings for the effect of compound 3361 on vector parasite stages, 1 mM compound 3361 demonstrated transmission blocking activity. These data indicate that novel chemotherapeutic interventions that target PfHT may be active against liver and, to a lesser extent, transmission stages, in addition to blood stages.
Priming of Protective Anti-Listeria monocytogenes Memory CD8+T Cells Requires a Functional SecA2 Secretion System
Authors: Rahmoun Massilva , Gros Marilyn , Campisi Laura , Bassand Delphine , Lazzari Anne , Massiera Christophe , Narni-Mancinelli Emilie , Gounon Pierre , Lauvau Grégoire
Published: March 2011

The SecA2 auxiliary secretion system of Gram-positive bacteria promotes the export of virulence proteins essential for colonization of the host in the case of bothMycobacterium tuberculosisandListeria monocytogenes, two intracellular bacteria causing diseases in humans. We and others have demonstrated that this secretion system is also linked to the onset of long-term CD8+T cell-mediated protective immunity in mice. In the case ofL. monocytogenes, expression of SecA2 inside the cytosol of infected cells correlates with the generation of CCL3-secreting memory CD8+T cells that are required for protection against secondary challenge with wild-type (wt)L. monocytogenes.Since the SecA2 ATPase is well conserved among Gram-positive pathogenic bacteria, we hypothesized that SecA2 itself bears evolutionarily conserved motifs recognized by cytosolic pattern recognition receptors, leading to signaling events promoting the differentiation of CCL3+memory CD8+T cells. To test this possibility, we generated a stableL. monocytogeneschromosomal mutant that expressed a SecA2 ATPase bearing a mutated nucleotide binding site (NBS). Similarly to a SecA2 deletion mutant, the NBS mutant exhibited rough colonies, a bacterial chaining phenotype, an impaired protein secretion profile, andin vivovirulence in comparison to wtL. monocytogenes. Importantly, mice immunized with the SecA2 NBS mutant were not protected against secondary infection with wtL. monocytogenesand did not develop CCL3+memory CD8+T cells. NBS mutant and wt SecA2 proteins were expressed to comparable extents by bacteria, suggesting that SecA2 itself is unlikely to promote the induction of these cells. Rather, one or several of the SecA2 substrate proteins released inside the cytosol of infected cells may be involved.
Role of the Accessory Gene Regulator
agr
in Community-Associated Methicillin-Resistant Staphylococcus aureus Pathogenesis
Authors: Cheung Gordon Y. C. , Wang Rong , Khan Burhan A. , Sturdevant Daniel E. , Otto Michael
Published: March 2011

The molecular basis underlying the pathogenic success of community-associated methicillin-resistant
Staphylococcus aureus
(CA-MRSA) is not completely understood, but differential gene expression has been suggested to account at least in part for the high virulence of CA-MRSA strains. Here, we show that the
agr
gene regulatory system has a crucial role in the development of skin infections in the most prevalent CA-MRSA strain USA300. Importantly, our data indicate that this is due to discrepancies between the
agr
regulon of CA-MRSA and those of hospital-associated MRSA and laboratory strains. In particular,
agr
regulation in strain USA300 led to exceptionally strong expression of toxins and exoenzymes, upregulation of fibrinogen-binding proteins, increased capacity to bind fibrinogen, and increased expression of methicillin resistance genes. Our findings demonstrate that
agr
functionality is critical for CA-MRSA disease and indicate that an adaptation of the
agr
regulon contributed to the evolution of highly pathogenic CA-MRSA.
Essential Role for Neutrophils in Pathogenesis and Adaptive Immunity in Chlamydia caviae Ocular Infections
Authors: Lacy H. Marie , Bowlin Anne K. , Hennings Leah , Scurlock Amy M. , Nagarajan Uma M. , Rank Roger G.
Published: March 2011

Trachoma, the world's leading cause of preventable blindness, is produced by chronic ocular infection with
Chlamydia trachomatis
, an obligate intracellular bacterium. While many studies have focused on immune mechanisms for trachoma during chronic stages of infection, less research has targeted immune mechanisms in primary ocular infections, events that could impact chronic responses. The goal of this study was to investigate the function of neutrophils during primary chlamydial ocular infection by using the guinea pig model of
Chlamydia caviae
inclusion conjunctivitis. We hypothesized that neutrophils help modulate the adaptive response and promote host tissue damage. To test these hypotheses, guinea pigs with primary
C. caviae
ocular infections were depleted of neutrophils by using rabbit antineutrophil antiserum, and immune responses and immunopathology were evaluated during the first 7 days of infection. Results showed that neutrophil depletion dramatically decreased ocular pathology, both clinically and histologically. The adaptive response was also altered, with increased
C. caviae
-specific IgA titers in tears and serum and decreased numbers of CD4
+
and CD8
+
T cells in infected conjunctivae. Additionally, there were changes in conjunctival chemokines and cytokines, such as increased expression of IgA-promoting interleukin-5 and anti-inflammatory transforming growth factor β, along with decreased expression of T cell-recruiting CCL5 (RANTES). This study, the first to investigate the role of neutrophils in primary chlamydial ocular infection, indicates a previously unappreciated role for neutrophils in modulating the adaptive response and suggests a prominent role for neutrophils in chlamydia-associated ocular pathology.
PREFORM MAP FOR UPSETTING ALUMINUM SPECIMENS AND ITS EXPERIMENTAL VERIFICATION
Authors: KAVITI AJAY KUMAR , PATHAK K. K. , HORA M. S.
Published: March 2011

This study deals with preform maps for near net shape upsetting of aluminum billets. These maps have been developed using finite element analysis results considering 10 interfacial friction conditions and varying geometrical and processing parameters. Preform maps are experimentally verified using aluminum specimens. The proposed approach offers a powerful tool for near net shape upsetting.
Separation of scattered concerns
Authors: Majumdar Dipankar , Kanjilal Ananya , Bhattacharya Swapan
Published: March 2011

Aspect Mining is a dynamic area of research in the field of Software Engineering. Aspects are concerns that are intermingled with other concerns thereby reducing the understandability, maintainability and scalability of the code. The concept of Separation of Concerns (SoC) is often achieved untill the Design Phase, but gets difficult in the later phases of the software development life cycle (SDLC). During program maintenance the maintenance team is left with an aggregation of procedures and variables, both of which may be generically called user-defined tokens. This paper proposes a graph-based approach to address the problem of SoC during program maintenance. This is done by the removal of some source code elements (e.g., user-defined-tokens), which can be responsible for tangled concerns and complex code. These user-definedtokens can be treated separately under the Aspect Oriented Programming paradigm. The paper proposes a graphical-model, which represents a procedural program and defines a mathematical- model to identify and remove the tangled and interleaving code-fragments. Thereafter these code fragments are traced back to the requirements engineering level through a formal traceability model. This process yields the corresponding user requirements that are associated with these scattered code fragments. These identified user requirements are put forward as Aspects, to be handled or re-engineered under the Aspect Oriented Programming paradigm.
Analysis of Projects and Volunteer Participation in Large Scale Free and Open Source Software Ecosystem
Authors: Krishna Raj P. M. , Srinivasa K . G.
Published: March 2011

The ecology of Free and Open Source Software (FOSS) is dotted by projects of every kind ranging from small desktop applications to large mission critical systems. To enable maximum visibility among the developer community, these projects are often hosted in community project management portals. The current work studies one such portal, sourceforge. net by analysing the data of 200,000 projects and 2 million developers for the period Feb 2005 to Aug 2009. The scope of the present study includes the analysis of developer contribution. The slow growth rate of developer community and high number of single developer projects are the major findings of the present work.
Online and incremental algorithms for facility location
Authors: Fotakis Dimitris
Published: March 2011

In the online and incremental variants of Facility Location, the demands arrive one-by-one and must be assigned to an open facility upon arrival, without any knowledge about future demands. In the online variant, the decisions of opening a facility at a particular location and of assigning a demand to some facility are irrevocable. In the incremental variant, the algorithm can also merge existing facilities (and the corresponding demand clusters) with each other, and only the decision of assigning some demands to the same facility is irrevocable. The goal is to maintain, either online or incrementally, a set of facilities and an assignment of the demands to them that minimize the total facility opening cost plus the assignment cost for all demands.

In this survey, we discuss the previous work on online and incremental algorithms for Facility Location. In addition to the main results, namely that the competitive ratio for the online variant is Θ(log
n
log log
n
), where
n
is the number of demands, and that the competitive ratio for the incremental variant is O(1), we discuss all known online and incremental Facility Location algorithms, sketch the intuition behind them and the main ideas of their competitive analysis, and discuss some applications.
Exploring Airway Diseases by NMR‐Based Metabonomics: A Review of Application to Exhaled Breath Condensate
Authors: Sofia Matteo , Maniscalco Mauro , de Laurentiis Guglielmo , Paris Debora , Melck Dominique , Motta Andrea
Published: March 2011

There is increasing evidence that biomarkers of exhaled gases or exhaled breath condensate (EBC) may help in detecting abnormalities in respiratory diseases mirroring increased, oxidative stress, airways inflammation and endothelial dysfunction. Beside the traditional techniques to investigate biomarker profiles, “omics” sciences have raised interest in the clinical field as potentially improving disease phenotyping. In particular, metabonomics appears to be an important tool to gain qualitative and quantitative information on low‐molecular weight metabolites present in cells, tissues, and fluids.
Here, we review the potential use of EBC as a suitable matrix for metabonomic studies using nuclear magnetic resonance (NMR) spectroscopy. By using this approach in airway diseases, it is now possible to separate specific EBC profiles, with implication in disease phenotyping and personalized therapy.