bluuebunny/crossref_metadata_2025 huggingface dataset:
Russian companies: the rise of new multinationals
Authors: Filippov Sergey
Published: July 2010

Purpose

The focus of this paper is the emergence of Russia's multinational companies. It aims to analyse their motives to internationalise as well as the approaches to internationalisation. While relevance of the theoretical perspectives is highlighted, the purpose of this paper is to contribute to the understanding of the present‐day phenomenon of emerging Russian multinationals.

Design/methodology/approach

The paper relies on a qualitative approach for the analysis of the nature of Russian multinationals. The phenomenon of the emerging Russian multinationals is analysed through the prism and using insights from a number of subjects, namely transition studies, politics, innovation studies and international business studies.

Findings

The paper traces the evolution of Russian companies; the idiosyncratic path of their formation serves as a background for understanding of their internationalisation strategies. A special attention is devoted to the R&D activities of Russian multinational companies, and access to foreign technology is found to be an important driver of internationalisation.

Research limitations/implications

The paper highlights relevance of further research on Russian multinationals and outlines research avenues.

Practical implications

The paper is rich in its practical implications. Specifically, it elaborates on the European Union‐Russian bilateral relations and the role of Russian multinationals in the European economies. The issue of political involvement is raised, and the paper seeks to identify whether Russian companies serve as tools of foreign policy, or they operate as business agents.

Originality/value

Despite their increasingly important role in the global economy, Russian companies have been largely overshadowed by the emergence of Indian and Chinese multinationals and not sufficiently addressed, even neglected, in the literature. Therefore, the objective of this paper is to fill in some gaps in the literature regarding this research area.
Indian pharmaceuticals in Brazil: emerging multinationals in emerging markets
Authors: Sweet Cassandra
Published: July 2010

Purpose

This paper fills a gap in burgeoning emerging country multinational company (EMNC) literatures by offering a region‐wide picture of changes occurring across one sector: pharmaceuticals. The purpose of this paper is to analyze the entry of Indian firms in the Latin American pharmaceutical market since the late 1990s.

Design/methodology/approach

The analysis builds on a multi‐method approach. Over 80 interviews with firm managers, policy makers and regulators are informed by a national database showing the relative importance of Indian exports in generics,similares(branded generics), public, and bulk chemical markets.

Findings

The paper's findings are twofold: first, contrary to popular intuition regarding developing EMNC activity – which suggests that firms from the developing world have competitive advantages in other developing countries – Indian pharmaceutical firms have learned that operating in a weak institutional environment does not confer specific market advantages. Second, Indian EMNCs have assumed both symbiotic and antagonistic roles, simultaneously cooperating and competing with local firms.

Research limitations/implications

The data are drawn from one industry, across one regional market. Future research could extend the approach, to investigate the southern‐directed strategies of EMNCs in other industries.

Practical implications

The findings of this paper suggest that EMNC managers should not rely on advantages typically described in EMNC literatures. The paper also suggests that public health and regulatory policy in Latin America should take into account the diversification of inputs and strength of Asian bulk chemical suppliers.

Originality/value

This paper enriches current EMNC literatures in which there is a dearth of research on EMNC approaches in emerging markets.
Worker‐specific Effects of Globalisation
Authors: Egger Hartmut , Kreickemeier Udo
Published: July 2010

This paper sets up a general equilibrium model, in which firms are heterogeneous due to productivity differences and workers have fairness preferences and hence provide full effort only if their factor return is sufficiently high. With the wage considered to be fair by workers depending on the operating profits of the firm in which they are employed, more productive firms in this setting are not only larger and make higher profits but they also have to pay higher wages due to rent‐sharing. This mechanism leads to wage differentiation even if all workers share the same individual characteristics. We use this framework to study worker‐specific effects of trade between two symmetric countries. Exporters in this setting make higher operating profits and hence have to pay higher wages than non‐exporters. This exporter wage premium provides a source for losses from trade and, all other things equal, makes a negative employment effect of trade more likely. Furthermore, it contributes significantly to a general increase in intra‐group income inequality among production workers when a country moves from autarky to trade.
The Profile of Inflammatory Cytokines in Gingival Crevicular Fluid around Healthy Osseointegrated Implants
Authors: Nowzari Hessam , Phamduong Sharon , Botero Javier Enrique , Villacres Maria C. , Rich Sandra K.
Published: July 2010

Objective: Regardless of gingival health and subgingival microbiology, production of cytokines within peri‐implant tissues may be different from that of teeth. The objective of this study was to describe the peri‐implant levels of pro‐inflammatory cytokines and subgingival microbiology in clinically healthy sites.

Materials and Methods: Subgingival plaque and gingival crevicular fluid (GCF) were obtained from 28 clinically healthy implants and 26 teeth selected from 24 individuals. Microbial composition was determined by selective anaerobic culture techniques. Pro‐inflammatory cytokines were quantified by flow cytometry analysis of GCF. The concentration of cytokines between implants and teeth were compared with the independent t‐test.

Results: The concentration of cytokines was higher in GCF from healthy implants than in teeth. The profile of cytokines was characteristic of an innate immune response. A more frequent detection of periodontopathic bacteria was observed in teeth than implants. Cultivable levels of periodontopathic bacteria were similar between implants and teeth.

Conclusions: Despite gingival tissue health and scarce plaque accumulation, the profile of inflammatory cytokines in implant crevicular fluid was distinctive of an innate immune response and in higher concentration than in teeth. Other than bacterial stimulus, intrinsic factors related to implants may account for more cytokine production than teeth.
Single Implant Treatment in Healing Versus Healed Sites of the Anterior Maxilla: An Aesthetic Evaluation
Authors: Cosyn Jan , Eghbali Aryan , De Bruyn Hugo , Dierens Melissa , De Rouck Tim
Published: July 2010

Purpose: The aim was to compare and document in detail the aesthetic outcome of single implant treatment in healing sites (early implant placement) with fully healed sites (conventional implant placement) of the anterior maxilla.

Materials and Methods: A cross‐sectional study in patients who had been treated by two periodontists and two prosthodontists in 2006 and 2007 was conducted. Surgical treatment involved standard flap elevation without releasing incisions and restorative procedures included cemented crowns in all patients. Only straightforward single implant treatments using Nobelreplace tapered TiUnite® implants (Nobel Biocare, Göteborg, Sweden) in healing sites (6–8 weeks following tooth extraction) and fully healed sites (≥6 months following tooth extraction) were considered with both neighboring teeth present and without the need for hard and/or soft tissue grafting. The aesthetic outcome was objectively rated using the pink esthetic score (PES) and white esthetic scrore (WES) by a blinded clinician who had not been involved in the treatment. Patients rated aesthetics by means of visual analogue scales.

Results: Twenty‐one out of 22 early and 25/27 conventional implant treatments were available for aesthetic evaluation after on average two and a half years of function (range 17–41 months). There were no significant differences for any of the criteria between the treatment concepts. Overall, papillae were most easy to satisfy, whereas alveolar process and tooth color most difficult. A thin‐scalloped biotype was associated with low distal papillae (p = .041) and alveolar process deficiency (p = .039). Twenty‐six percent of the cases were aesthetic failures (PES < 8 and/or WES < 6) and 13% showed an (almost) perfect outcome (PES ≥ 12 and WES ≥ 9). The remainder (61%) demonstrated acceptable aesthetics. There was no significant correlation between objective and subjective ratings.

Conclusions: Early and conventional single implant treatment yielded comparable aesthetic outcome. Albeit all treatments had been performed by experienced clinicians and only straightforward cases had been selected, 1 out of 4 cases were aesthetic failures and only a strict minority showed perfection. Research is required on the aesthetic outcome of alternative surgical procedures especially in high‐risk patients with a thin‐scalloped biotype.
Nutrition in Space: Evidence from the U.S. and the U.S.S.R.
Authors: Lane Helen W.
Published: July 2010

Space flight exposes humans to a hostile, stressful environment as well as to the weightlessness associated with microgravity. The stresses of space travel affect nutritional balance, as evidenced by interrelated changes in body composition, energy utilization, and endocrine function. The limited data gathered thus far suggest that space flight incurs acute decreases in fluid mass and chronic, ongoing changes in muscle and bone mass. Concurrent with these changes is an increase in energy used per unit body mass. Other preliminary data suggest that bed rest and space flight may incur increased sensitivity to insulin. Further research is needed to determine the human energy and protein requirements for space, as well as a means of quantifying changes in body composition during extended-duration space flight.
FAST Code System: Review of Recent Developments and Near-Future Plans
Authors: Mikityuk Konstantin , Krepel Jiri , Pelloni Sandro , Chenu Aurelia , Petkevich Petr , Chawla Rakesh
Published: July 2010

The FAST code system is currently being developed and used at the Paul Scherrer Institut for static and transient analysis of the main Generation 4 fast-spectrum reactor concepts: sodium-, helium-, and gas-cooled fast reactors. The code system includes the ERANOS code system for static neutronics calculations, as well as coupled TRACE/PARCS/FRED for neutron kinetics, thermal hydraulic, and fuel transient analysis. The paper presents the status of the recent developments in neutronics (new 3D procedure for equilibrium cycle simulation and new transient cross section generation procedure), in thermal hydraulics and chemistry (equations-of-state for new coolants, two-phase flow models for sodium, and new model for oxide layer buildup in heavy-metal flow), and in fuel behavior (new model for the dispersed gas-cooled fast reactor fuel). Near-future plans for the further development of FAST are outlined.
Residual Life Assessment of Steam Generators With Alloy 600 TT Tubing: Methods and Application
Authors: de Curieres Ian , Meunier Marie-Christine , Joly Pierre
Published: July 2010

The aim of the paper is to introduce methods to estimate the residual life of steam generators with alloy 600 thermally treated (TT) tubing, taking into account primary water stress corrosion cracking (PWSCC) as the main contributor damage. The methods take into account both initiation and propagation of PWSCC cracks in the expansion transition zone of steam generator tubes, as well as the current damage status (cracking and plugging) of the tube bundle, known from inspection results. A probabilistic model is used to treat initiation, while the propagation stage is treated in a deterministic way based on inspection data. After introducing the methods used to assess the residual life, a brief parametric study will be shown to illustrate the effects of initiation versus propagation. Eventually, the cases of a few actual steam generators with tubing made of alloy 600 TT showing different situations of present damage and damage evolution rates will be presented.
Linear and Nonlinear Stability Analysis of a Supercritical Natural Circulation Loop
Authors: Sharma Manish , Vijayan P. K. , Pilkhwal D. S. , Saha D. , Sinha R. K.
Published: July 2010

Supercritical water (SCW) has excellent heat transfer characteristics as a coolant for nuclear reactors. Besides it results in high thermal efficiency of the plant. However, the flow can experience instabilities in supercritical water cooled reactors, as the density change is very large for the supercritical fluids. A computer code SUCLIN has been developed employing supercritical water properties to carry out the steady-state and linear stability analysis of a SCW natural circulation loop (SCWNCL). The conservation equations of mass, momentum, and energy have been linearized by imposing small perturbation in flow rate, enthalpy, pressure, and specific volume. The equations have been solved analytically to generate the characteristic equation. The roots of the equation determine the stability of the system. The code has been benchmarked against published results. Then the code has been extensively used for studying the effect of diameter, heater inlet temperature, and pressure on steady-state and stability behavior of a SCWNCL. A separate computer code, NOLSTA, has been developed, which investigates stability characteristics of supercritical natural circulation loop using nonlinear analysis. The conservation equations of mass, momentum, and energy in transient form were solved numerically using finite volume method. The stable, unstable, and neutrally stable points were identified by examining the amplitude of flow and temperature oscillations with time for a given set of operating conditions. The stability behavior of loop, predicted using nonlinear analysis has been compared with that obtained from linear analysis. The results show that the stability maps obtained by the two methods agree qualitatively. The present paper describes the linear and nonlinear stability analysis models and the results obtained in detail.
Competitiveness of Small-Medium, New Generation Reactors: A Comparative Study on Decommissioning
Authors: Locatelli Giorgio , Mancini Mauro
Published: July 2010

Small-medium reactors (SMRs) are going to be important players in the worldwide nuclear renaissance. The economy of scale plays against the development of this kind of reactors, even if sometimes its influence is overestimated so that SMRs appear to have a levelized unit electricity cost significantly higher than large reactors (LRs). However, the economy of scale applies only if SMR designs are similar to that of LRs, but this is not the case since the small size allows for original design solutions not accessible to large sized reactors. The literature already presents studies showing how, under certain assumptions, the capital cost and the operation and maintenance cost of a site provided by one large reactor is quite similar to another site composed of four SMRs providing the same power output. However, the literature still lacks this kind of analysis on the decommissioning cost. The paper fills this gap, investigating the cost breakdown of a decommissioning project and providing a literature review about its cost estimate techniques and managerial approach. This paper identifies and briefly discusses the different cost drivers related to the decommissioning phase of a nuclear plant focusing the attention on those critical ones in the comparison between SMR and LR (economy of scale, multiple units in a single site, technical savings, and decommissioning strategy—“immediate decommissioning” or “deferred decommissioning”). The International Reactor Innovative and Secure reactor is used as the example of a SMR to quantify the effect of these drivers, but the analysis and conclusions are applicable to the whole spectrum of new small nuclear plants. The results show that when all of these factors are accounted for in a set of realistic and comparable configurations, and with the same power installed on the site, the decommissioning costs of a SMR with respect to a LR drop from three times higher to two times. If more than one large reactor is considered, the gap increases since the large reactor investment also reaps advantages from site sharing.
Experimental Study on Gas Entrainment Due to Nonstationary Vortex in a Sodium Cooled Fast Reactor—Comparison of Onset Conditions Between Sodium and Water
Authors: Kimura Nobuyuki , Ezure Toshiki , Miyakoshi Hiroyuki , Kamide Hideki , Fukuda Takeshi
Published: July 2010

An innovative sodium cooled fast reactor has been investigated as part of the fast reactor cycle technology development project. In the reactor, a compact reactor vessel (R/V) with increased sodium flow velocity was designed to reduce the construction cost. One of the thermal hydraulic problems in this design is gas entrainment at the free surface in the R/V. In most of past studies, water experiments were performed to investigate the gas entrainment in the reactor. It is necessary to evaluate an influence of fluid physical property on the gas entrainment phenomena. In this study, sodium experiments were carried out to clarify the onset criteria of the gas entrainment due to a free surface vortex. Water experiments using a test section in which geometry is the same as that in the sodium tests were also performed. The gas entrainment in water slightly tended to take place in comparison with that in sodium under low velocity conditions. Overall, the onset condition map on the lateral and downward flow velocities in the sodium and water experiments were in good agreement.
Measurement and Analysis for Rewetting Velocity Under Post-BT Conditions During Anticipated Operational Occurrence of BWR
Authors: Yasuteru Sibamoto , Yu Maruyama , Hideo Nakamura
Published: July 2010

A series of experiments was performed for rewetting phenomena on dried-out fuel rod surfaces under post-boiling transition (post-BT) conditions with high-pressure and high-water flow rate simulating anticipated operational occurrences of a BWR. An analytical model for rewetting velocity, defined by a propagation velocity of a quench front, has been developed on the basis of the experimental results. The rewetting for the post-BT condition is characterized by the faster propagation of the quench front than that for reflood phase conditions during a postulated large-break loss-of-coolant accident. In order to provide an explanation of this characteristic, the present analytical model took an effect of a precursory cooling into account by modifying the existing correlation by Sun et al. (1975, “Effects of Precursory Cooling on Falling-Film Rewetting,” ASME J. Heat Transfer, 97, pp. 360–365), which is based on a one-dimensional analysis in a flow direction during the reflood phase. The present model demonstrates that the precursory cooling can significantly increase the rewetting velocity by more than an order of magnitude. Applying the experimental correlation developed in the separately conducted experiment into the heat transfer coefficient in the present model at a wet and a dry region with precursory cooling, our data of the rewetting velocity as well as the wall temperature profiles for the variable flow rates are successfully predicted.
Risk-Informed Approach for the Regulation of Decommissioning of Nuclear Facilities
Authors: Iguchi Yukihiro , Kato Masami
Published: July 2010

During decommissioning of nuclear facilities, it is generally thought that the risk is relatively low after high activity inventory such as the spent fuel is removed. However, dismantlement works may be carried out with nonmultiple barriers with a nonregular process depending mainly on human activities. Moreover, fire or gas incidents caused by conventional industry methods may lead to accidents with radioactivity release. This means more attention is necessary for safer dismantlement, especially for nuclear reactors with high activity. Therefore, utilization of risk information based on risk assessment of the decommissioning was proposed. A method of risk assessment for decommissioning was developed and applied for the dismantlement of typical reactor facilities and nuclear fuel facilities (a uranium enrichment plant and a reprocessing plant). The results show that the consequences of such troubles are low but their occurrences are still not negligible. This fact is supported by past trouble cases. Taking into account the risk assessment results, a methodology to secure the safety of decommissioning was proposed. It consists of four steps, i.e., (1) risk-informed approach, (2) graded approach, (3) phased approach, and (4) layered approach and the results can be reflected to the management and regulation. The regulation means, for example, the review of decommissioning plan or the operational safety program, the periodic safety inspections and usual monitoring. The methodology can evaluate the risk level of decommissioning more objectively and enable reasonable regulation based on the risk level. This leads to the appropriate distribution of resources for safety enhancement.
A Comparative Study of Single-Phase, Two-Phase, and Supercritical Natural Circulation in a Rectangular Loop
Authors: Vijayan P. K. , Sharma M. , Pilkhwal D. S. , Saha D. , Sinha R. K.
Published: July 2010

A one-dimensional theoretical model has been used to analyze the steady state and stability performance of a single-phase, two-phase, and supercritical natural circulation in a uniform diameter rectangular loop. Parametric influences of diameter, inlet temperature, and system pressure on the steady state and stability performance have been studied. In the single-phase liquid filled region, the flow rate is found to increase monotonically with power. On the other hand, the flow rate in two-phase natural circulation systems is found to initially increase, reach a peak, and then decrease with power. For the supercritical region also, the steady state behavior is found to be similar to that of the two-phase region. However, if the heater inlet temperature is beyond the pseudo critical value, then the performance is similar to single-phase loops. Also, the supercritical natural circulation flow rate decreases drastically during this condition. With an increase in loop diameter, the flow rate is found to enhance for all the three regions of operation. Pressure has a significant influence on the flow rate in the two-phase region, marginal effect in the supercritical region, and practically no effect in the single-phase region. With the increase in loop diameter, operation in the single-phase and supercritical regions is found to destabilize, whereas the two-phase loops are found to stabilize. Again, pressure has a significant influence on stability in the two-phase region.
Three Dimensional Modeling of the Hydrodynamics of Oblique Droplet-Hot Wall Interactions During the Reflood Phase After a LOCA
Authors: Chatzikyriakou D. , Walker S. P. , Belhouachi B. , Narayanan C. , Lakehal D. , Hewitt G. F.
Published: July 2010

During the reflood phase, following a loss-of-coolant-accident (LOCA), the main mechanism for the precursory cooling of the fuel is by convective heat transfer to the vapor, with the vapor being cooled by the evaporation of the entrained saturated droplets. However, it is believed that the droplets that reach the rod could have an effect on this cooling process. Despite the fact that those droplets do not actually wet the fuel rod due to the formation of a vapor film that sustains them and prevents them from touching the wall, the temperature drop caused by the impingement of such water droplets on a very hot solid surface (whose temperature is beyond the Leidenfrost temperature (1966, “A Track About Some Qualities of Common Water,” Int. J. Heat Mass Transfer, 9, pp. 1153–1166)) is of the order of 30–150°C (2008, The Role of Entrained Droplets in Precursory Cooling During PWR Post-LOCA Reflood, TOPSAFE, Dubrovnik, Croatia, 1995, “Heat Transfer During Liquid Contact on Superheated Surfaces,” ASME J. Heat Transfer, 117, pp. 693–697). The associated heat flux is of the order of 105–107 W/m2 and the heat extracted is in the range of 0.05 J over the time period of the interaction (a few ms) (2008, The Role of Entrained Droplets in Precursory Cooling During PWR Post-LOCA Reflood, TOPSAFE, Dubrovnik, Croatia, 1995, “Heat Transfer During Liquid Contact on Superheated Surfaces,” ASME J. Heat Transfer, 117, pp. 693–697). The hydrodynamic behavior of the droplets upon impingement is reported to affect the heat transfer effectiveness of the droplets. In the dispersed flow regime the droplets are more likely to impinge on the hot surface at a very small angle sliding along the solid wall, still without actually touching it, and remaining in a close proximity for a much larger time period. This changes the heat transfer behavior of the droplet. Here, we investigate numerically the hydrodynamics of the impingement of such droplets on a hot solid surface at various incident angles and various velocities of approach. For our simulations, we use a computational fluid dynamics (CFD), finite-volume computational algorithm (TransAT©). The level set method is used for the tracking of the interface. We present three-dimensional results of those impinging droplets. The validation of our simulation is done against experimental data already available in the literature. Then, we compare the findings of those results with previous correlations.
Integration of Degradation Models Into Generation Risk Assessment: Challenges and Modeling Approaches
Authors: Jyrkama Mikko I. , Pandey Mahesh D. , Hess Stephen M.
Published: July 2010

The main objective of generation risk assessment (GRA) is to assess the impact of equipment unavailability and failures on the ability of the plant to produce power over time. The system reliability models employed for this purpose are based on the standard fault tree/event tree approach, which assumes failure rates to be constant. However, this ignores the impact of aging degradation and results in static estimates of expected generation loss. Component and equipment degradation not only increases the probability of failure over time, but also contributes to generation risk through increased unavailability and costs arising from greater requirement for inspection and replacement of degraded components. This paper discusses some of the key challenges associated with integrating the results of component degradation models into GRA. Because many analytical and simulation methods are subject to limitations, the methodology and modeling approach proposed in this work builds on the current GRA practice using the fault tree approach. The modeling of component degradation can be done separately at the fault tree cut set level, assuming the cut sets are independent and the component unavailabilities are relatively small. In order to capture the joint contribution of equipment failure and unavailability to generation risk, new risk-based importance measures are also developed using the concept of net present value.
Industry Practice for the Neutron Irradiation Embrittlement of Reactor Pressure Vessels in Japan
Authors: Yamashita Norimichi , Iwasaki Masanobu , Dozaki Koji , Soneda Naoki
Published: July 2010

Neutron irradiation embrittlement of reactor pressure vessel steels (RPVs) is one of the important material aging issues. In Japan, almost 40 years have past since the first plant started its commercial operation, and several plants are expected to become beyond 40 years old in the near future. Thus, the safe operation, based on the appropriate recognition of the neutron irradiation embrittlement, is inevitable to ensure the structural integrity of RPVs. The amount of the neutron irradiation embrittlement of RPV steels has been monitored and predicted by the complemental use of the surveillance program and embrittlement correlation method. Recent surveillance data suggest some discrepancies between the measurements and predictions of the embrittlement in some old boiling water reactor (BWR) RPV steels with high impurity content. Some discrepancies of pressurized water reactor (PWR) RPV surveillance data from the predictions have also been recognized in the embrittlement trend. Although such discrepancies are basically within a scatter band, the increasing necessity of the improvement of the predictive capability of the embrittlement correlation method has been emphasized to be prepared for the future long term operation. Regarding the surveillance program, on the other hand, only one original surveillance capsule, except for the reloaded capsules containing Charpy broken halves, is available in some BWR plants. This situation strongly pushed establishing a new code for a new surveillance program, where the use of the reloading and reconstitution of the tested specimens is specified. The Japan Electric Association Code, JEAC 4201-2007 “Method of Surveillance Tests for Structural Materials of Nuclear Reactors,” was revised in December 2007, in order to address these issues. A new mechanism-guided embrittlement correlation method was adopted. The surveillance program was modified for the long term operation of nuclear plants by introducing the “long term surveillance program,” which is to be applied for the operation beyond 40 years. The use of the reloading, reirradiation, and reconstitution of the tested Charpy/fracture toughness specimens is also specified in the new revision. This paper reports the application and practice of the JEAC4201-2007 in terms of the prediction of embrittlement and the use of tested surveillance specimens in Japan.
Photographic Study on Bubble Motion in Subcooled Pool Boiling
Authors: Okawa Tomio , Harada Takahiro , Kotsusa Yuta
Published: July 2010

Using a static contact angle of a vertical heated wall as a main experimental parameter, a photographic study was carried out to elucidate the mechanisms to determine the vapor bubble dynamics during subcooled pool boiling. The test fluid was distilled water and the experiments were performed under the atmospheric pressure; liquid subcooling was set to around 5 K. To enable clear observation of bubble behavior with a high speed camera, the experiments were conducted in an isolated bubble regime near the onset of nucleate boiling. Distinctly different bubble behaviors were observed on hydrophobic and hydrophilic surfaces: the bubbles were adhered to the surface for a long period of time when the contact angle was large while lifted-off the surface within a short period of time after the nucleation when the contact angle was small. Since buoyancy does not remove the bubble from the vertical surface, the mechanisms of bubble lift-off were investigated. It was indicated that the change in bubble shape induced by the surface tension force, unsteady growth force, and local liquid flow induced by heterogeneous condensation around the bubble are considered to promote the bubble lift-off while the surface tension force acting on the three-phase common line prevented the lift-off. Effects of the surface wettability on the lift-off bubble diameter, the elapsed time from the nucleation at the lift-off, and the condensation rate after the lift-off were also investigated.
Pronounced Effect of the Nature of the Inoculum on Biofilm Development in Flow Systems
Authors: Kroukamp Otini , Dumitrache Romeo G. , Wolfaardt Gideon M.
Published: July 2010

Biofilm formation renders sessile microbial populations growing in continuous-flow systems less susceptible to variation in dilution rate than planktonic cells, where dilution rates exceeding an organism's maximum growth rate (μ
max
) results in planktonic cell washout. In biofilm-dominated systems, the biofilm's overall μ
max
may therefore be more relevant than the organism's μ
max
, where the biofilm μ
max
is considered as a net process dependent on the adsorption rate, growth rate, and removal rate of cells within the biofilm. Together with lag (acclimation) time, the biofilm's overall μ
max
is important wherever biofilm growth is a dominant form, from clinical settings, where the aim is to prevent transition from lag to exponential growth, to industrial bioreactors, where the aim is to shorten the lag and rapidly reach maximum activity. The purpose of this study was to measure CO
2
production as an indicator of biofilm activity to determine the effect of nutrient type and concentration and of the origin of the inoculum on the length of the lag phase, biofilm μ
max
, and steady-state metabolic activity of
Pseudomonas aeruginosa
PA01 (containing
gfp
),
Pseudomonas fluorescens
CT07 (containing
gfp
), and a mixed community. As expected, for different microorganisms the lengths of the lag phase in biofilm development and the biofilm μ
max
values differ, whereas different nutrient concentrations result in differences in the lengths of lag phase and steady-state values but not in biofilm μ
max
rates. The data further showed that inocula from different phenotypic origins give rise to lag time of different lengths and that this influence persists for a number of generations after inoculation.
Isolation and Characterization of
Campylobacter
spp. from Antarctic Fur Seals (
Arctocephalus gazella
) at Deception Island, Antarctica
Authors: García-Peña F. J. , Pérez-Boto D. , Jiménez C. , San Miguel E. , Echeita A. , Rengifo-Herrera C. , García-Párraga D. , Ortega-Mora L. M. , Pedraza-Díaz S.
Published: July 2010

The presence of
Campylobacter
spp. was investigated in 41 Antarctic fur seals (
Arctocephalus gazella
) and 9 Weddell seals (
Leptonychotes weddellii
) at Deception Island, Antarctica. Infections were encountered in six Antarctic fur seals. The isolates, the first reported from marine mammals in the Antarctic region, were identified as
Campylobacter insulaenigrae
and
Campylobacter lari
.
The Prevalence of Multidrug Resistance Is Higher among Bovine than HumanSalmonellaentericaSerotype Newport, Typhimurium, and 4,5,12:i:− Isolates in the United States but Differs by Serotype and Geographic Region
Authors: Hoelzer K. , Soyer Y. , Rodriguez-Rivera L. D. , Cummings K. J. , McDonough P. L. , Schoonmaker-Bopp D. J. , Root T. P. , Dumas N. B. , Warnick L. D. , Gröhn Y. T. , Wiedmann M. , Baker K. N. K. , Besser T. E. , Hancock D. D. , Davis M. A.
Published: July 2010

Salmonellarepresents an important zoonotic pathogen worldwide, but the transmission dynamics between humans and animals as well as within animal populations are incompletely understood. We characterizedSalmonellaisolates from cattle and humans in two geographic regions of the United States, the Pacific Northwest and the Northeast, using three common subtyping methods (pulsed-field gel electrophoresis [PFGE], multilocus variable number of tandem repeat analysis [MLVA], and multilocus sequence typing [MLST]). In addition, we analyzed the distribution of antimicrobial resistance among human and cattleSalmonellaisolates from the two study areas and characterizedSalmonellapersistence on individual dairy farms. For bothSalmonella entericasubsp.entericaserotypes Newport and Typhimurium, we found multidrug resistance to be significantly associated with bovine origin of isolates, with the odds of multidrug resistance for Newport isolates from cattle approximately 18 times higher than for Newport isolates from humans. Isolates from the Northwest were significantly more likely to be multidrug resistant than those from the Northeast, and susceptible and resistant isolates appeared to represent distinctSalmonellasubtypes. We detected evidence for strain diversification duringSalmonellapersistence on farms, which included changes in antimicrobial resistance as well as genetic changes manifested in PFGE and MLVA pattern shifts. While discriminatory power was serotype dependent, the combination of PFGE data with either MLVA or resistance typing data consistently allowed for improved subtype discrimination. Our results are consistent with the idea that cattle are an important reservoir of multidrug-resistantSalmonellainfections in humans. In addition, the study provides evidence for the value of including antimicrobial resistance data in epidemiological investigations and highlights the benefits and potential problems of combining subtyping methods.
Concentrations, Viability, and Distribution of
Cryptosporidium
Genotypes in Lagoons of Swine Facilities in the Southern Piedmont and in Coastal Plain Watersheds of Georgia
Authors: Jenkins Michael B. , Liotta Janice L. , Lucio-Forster Araceli , Bowman Dwight D.
Published: July 2010

Waste lagoons of swine operations are a source of
Cryptosporidium
oocysts. Few studies, however, have reported on oocyst concentrations in swine waste lagoons; none have reported on oocyst viability status, nor has there been a systematic assessment of species/genotype distributions across different types of swine facilities. Ten swine waste lagoons associated with farrowing, nursery, finishing, and gestation operations were each sampled once a month for a year. Oocysts were extracted from triplicate 900-ml effluent samples, enumerated by microscopy, and assessed for viability by dye exclusion/vital stain assay. DNA was extracted from processed samples, and 18S ribosomal DNA (rDNA) genes were amplified by PCR and sequenced for species and genotype identification. Oocysts were observed at each sampling time at each lagoon. Annual mean concentrations of total oocysts and viable oocysts ranged between 24 and 51 and between 0.6 and 12 oocysts ml
−1
effluent, respectively. The species and genotype distributions were dominated (95 to 100%) by
Cryptosporidium suis
and
Cryptosporidium
pig genotype II, the latter of which was found at eight of the lagoons. The lagoon at the gestation facility was dominated by
Cryptosporidium muris
(90%), and one farrowing facility showed a mix of pig genotypes,
Cryptosporidium muris
, and various genotypes of
C. parvum
. The zoonotic
C. parvum
bovine genotype was observed five times out of 407 18S rDNA sequences analyzed. Our results indicate that pigs can have mixed
Cryptosporidium
infections, but infection with
C. suis
is likely to be dominant.
Characterization of Novel
Brucella
Strains Originating from Wild Native Rodent Species in North Queensland, Australia
Authors: Tiller Rebekah V. , Gee Jay E. , Frace Michael A. , Taylor Trevor K. , Setubal Joao C. , Hoffmaster Alex R. , De Barun K.
Published: July 2010

We report on the characterization of a group of seven novel
Brucella
strains isolated in 1964 from three native rodent species in North Queensland, Australia, during a survey of wild animals. The strains were initially reported to be
Brucella suis
biovar 3 on the basis of microbiological test results. Our results indicated that the rodent strains had microbiological traits distinct from those of
B. suis
biovar 3 and all other
Brucella
spp. To reinvestigate these rodent strains, we sequenced the 16S rRNA,
recA
, and
rpoB
genes and nine housekeeping genes and also performed multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA). The rodent strains have a unique 16S rRNA gene sequence compared to the sequences of the classical
Brucella
spp. Sequence analysis of the
recA
,
rpoB
, and nine housekeeping genes reveals that the rodent strains are genetically identical to each other at these loci and divergent from any of the currently described
Brucella
sequence types. However, all seven of the rodent strains do exhibit distinctive allelic MLVA profiles, although none demonstrated an amplicon for VNTR 07, whereas the other
Brucella
spp. did. Phylogenetic analysis of the MLVA data reveals that the rodent strains form a distinct clade separate from the classical
Brucella
spp. Furthermore, whole-genome sequence comparison using the maximal unique exact matches index (MUMi) demonstrated a high degree of relatedness of one of the seven rodent
Brucella
strains (strain NF 2653) to another Australian rodent
Brucella
strain (strain 83-13). Our findings strongly suggest that this group of
Brucella
strains isolated from wild Australian rodents defines a new species in the
Brucella
genus.
Presence of
Bacteroidales
as a Predictor of Pathogens in Surface Waters of the Central California Coast
Authors: Schriewer Alexander , Miller Woutrina A. , Byrne Barbara A. , Miller Melissa A. , Oates Stori , Conrad Patricia A. , Hardin Dane , Yang Hsuan-Hui , Chouicha Nadira , Melli Ann , Jessup Dave , Dominik Clare , Wuertz Stefan
Published: July 2010

The value of
Bacteroidales
genetic markers and fecal indicator bacteria (FIB) to predict the occurrence of waterborne pathogens was evaluated in ambient waters along the central California coast.
Bacteroidales
host-specific quantitative PCR (qPCR) was used to quantify fecal bacteria in water and provide insights into contributing host fecal sources. Over 140 surface water samples from 10 major rivers and estuaries within the Monterey Bay region were tested over 14 months with four
Bacteroidales
-specific assays (universal, human, dog, and cow), three FIB (total coliforms, fecal coliforms, and enterococci), two protozoal pathogens (
Cryptosporidium
and
Giardia
spp.), and four bacterial pathogens (
Campylobacter
spp.,
Escherichia coli
O157:H7,
Salmonella
spp., and
Vibrio
spp.). Indicator and pathogen distribution was widespread, and detection was not highly seasonal.
Vibrio cholerae
was detected most frequently, followed by
Giardia
,
Cryptosporidium
,
Salmonella
, and
Campylobacter
spp. Bayesian conditional probability analysis was used to characterize the
Bacteroidales
performance assays, and the ratios of concentrations determined using host-specific and universal assays were used to show that fecal contamination from human sources was more common than livestock or dog sources in coastal study sites. Correlations were seen between some, but not all, indicator-pathogen combinations. The ability to predict pathogen occurrence in relation to indicator threshold cutoff levels was evaluated using a weighted measure that showed the universal
Bacteroidales
genetic marker to have a comparable or higher mean predictive potential than standard FIB. This predictive ability, in addition to the
Bacteroidales
assays providing information on contributing host fecal sources, supports using
Bacteroidales
assays in water quality monitoring programs.
Eugenol Reduces the Expression of Virulence-Related Exoproteins in
Staphylococcus aureus
Authors: Qiu Jiazhang , Feng Haihua , Lu Jing , Xiang Hua , Wang Dacheng , Dong Jing , Wang Jianfeng , Wang Xiaoliang , Liu Juxiong , Deng Xuming
Published: July 2010

Eugenol, an essential oil component in plants, has been demonstrated to possess activity against both Gram-positive and Gram-negative bacteria. This study examined the influence that subinhibitory concentrations of eugenol may have on the expression of the major exotoxins produced by
Staphylococcus aureus
. The results from a tumor necrosis factor (TNF) release assay and a hemolysin assay indicated that
S. aureus
cultured with graded subinhibitory concentrations of eugenol (16 to 128 μg/ml) dose dependently decreased the TNF-inducing and hemolytic activities of culture supernatants. Western blot analysis showed that eugenol significantly reduced the production of staphylococcal enterotoxin A (SEA), SEB, and toxic shock syndrome toxin 1 (the key exotoxins to induce TNF release), as well as the expression of α-hemolysin (the major hemolysin to cause hemolysis). In addition, this suppression was also evaluated at the transcriptional level via real-time reverse transcription (RT)-PCR analysis. The transcriptional analysis indicated that 128 μg/ml of eugenol remarkably repressed the transcription of the
S. aureus sea
,
seb
,
tst
, and
hla
genes. According to these results, eugenol has the potential to be rationally applied on food products as a novel food antimicrobial agent both to inhibit the growth of bacteria and to suppress the production of exotoxins by
S. aureus
.
High Diversity of Extended-Spectrum Beta-Lactamase-Producing Bacteria in an Urban River Sediment Habitat
Authors: Lu Su-Ying , Zhang Ya-Li , Geng Sui-Na , Li Tian-Yu , Ye Zhuo-Ming , Zhang Dong-Sheng , Zou Fei , Zhou Hong-Wei
Published: July 2010

Antibiotic-resistant bacteria (ARB) have been surveyed widely in water bodies, but few studies have determined the diversity of ARB in sediment, which is the most taxon-abundant habitat in aquatic environments. We isolated 56 extended-spectrum β-lactamase (ESBL)-producing bacteria from a single sediment sample taken from an urban river in China. All strains were confirmed for ESBL-producing capability by both the clavulanic acid combination disc method and MIC determination. Of the isolated strains, 39 were classified asEnterobacteriaceae(consisting of the generaEscherichia,Klebsiella,Serratia, andAeromonas) by 16S rRNA gene sequencing and biochemical analysis. The present study identifies, for the first time, ESBL-producing strains from the familiesBrucellaceaeandMoraxellaceae. TheblaCTX-Mgene was the most dominant of the ESBL genes (45 strains), while theblaTEMgene was the second-most dominant (22 strains). A total of five types ofblaCTX-Mfragments were identified, with both known and novel sequences. A library ofblaCTX-Mcloned from the sediment DNA showed an even higher diversity ofblaCTX-Msequences. The discovery of highly diverse ESBL-producing bacteria and ESBL genes, particularlyblaCTX, in urban river sediment raises alarms for potential dissemination of ARB in communities through river environments.
Estimation of Uptake of Humic Substances from Different Sources by
Escherichia coli
Cells under Optimum and Salt Stress Conditions by Use of Tritium-Labeled Humic Materials
Authors: Kulikova Natalia A. , Perminova Irina V. , Badun Gennady A. , Chernysheva Maria G. , Koroleva Olga V. , Tsvetkova Eugenia A.
Published: July 2010

The primary goal of this paper is to demonstrate potential strengths of the use of tritium-labeled humic substances (HS) to quantify their interaction with living cells under various conditions. A novel approach was taken to study the interaction between a model microorganism and the labeled humic material. The bacterium
Escherichia coli
was used as a model microorganism. Salt stress was used to study interactions of HS with living cells under nonoptimum conditions. Six tritium-labeled samples of HS originating from coal, peat, and soil were examined. To quantify their interaction with
E. coli
cells, bioconcentration factors (BCF) were calculated and the amount of HS that penetrated into the cell interior was determined, and the liquid scintillation counting technique was used as well. The BCF values under optimum conditions varied from 0.9 to 13.1 liters kg
−1
of cell biomass, whereas under salt stress conditions the range of corresponding values increased substantially and accounted for 0.2 to 130 liters kg
−1
. The measured amounts of HS that penetrated into the cells were 23 to 167 mg and 25 to 465 mg HS per kg of cell biomass under optimum and salt stress conditions, respectively. This finding indicated increased penetration of HS into
E. coli
cells under salt stress.