bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Convective-Radiative Thermal Analysis of a Solar Flat-Plate Collector
Authors: Eicoff Aaron P. , Naraghi Mohammad H.
Published: October 2015

A model for the combined spectral radiative, conductive and convective heat transfer analysis of solar water heaters is presented. The radiation aspect of this model is based on the spectral distribution of the solar irradiance and spectrally selective properties of the system components. The convective equations that were used are based on well-established empirical models. The heat transfer characteristics of the solar water heater are determined by simultaneously solving a nonlinear system of energy balance equations for the various physical components using an iterative approach. The model is used to predict temperatures and heat fluxes for a typical flat-plate solar collector for various geometries and conditions i.e. flow rates, solar irradiances and spectral properties.
Analysis of “Finger” Flame Acceleration as a Stage of a Methane-Air-Dust Fire in a Coal Mine
Authors: Demir Sinan , Akkerman V’yacheslav , Rangwala Ali S. , Bychkov Vitaly
Published: October 2015

To reveal the inner mechanism of gas explosion, the entire scenario of premixed flame front evolution within an accidental fire is prescribed. Specifically, “finger” flame shape, which is one of the key stages of flame evolution, is scrutinized with the situation of a methane-air explosion. A transition from a globally-spherical front to a finger-shaped one occurs when a flame starts approaching the passage walls. While this acceleration is extremely strong, it stops as soon as the flame touches the passage wall. This mechanism is Reynolds-independent; being equally relevant to micro-channels and giant tunnels. The flame speed increases by an order of magnitude during this stage. To implement dusty environments, Seshadri formulation for the planar flame [Combustion and Flame 89 (1992) 333] is employed with a non-uniform distribution of inert dust gradients, specifically, linear, parabolic and hyperbolic spatial dust distribution gradients are incorporated into the “finger” flame shape. This study systematically investigates how the noncombustible dust distributions affect fire evolution, the flame shape, and propagation velocity.
Study on Washing Strategy Model of Gas Turbines
Authors: Yang Huadong , Zhang Xia
Published: October 2015

Fouling in the compressor and turbine, from particles (such as dust, pollen, seed, insect and unburned hydrocarbon) deposited on the blade results in the change of blade profile, thus flow area is reduced. Many researches have demonstrated that fouling can result in the reduction of power and efficiency, and can result in the increase running costs. At present, the most effective control method for gas turbine fouling is off-line washing, but off-line washing may seriously affect the unit’s benefit. So, it is very important to determine the optimal washing cycle. In previous studies, many researchers determine the washing time based on the reduction level of thermodynamic parameters, such as the change of compressor pressure ratio. But, research demonstrated that other failure modes (such as erosion, corrosion and tip clearance increase) can result in the similar change. So, it is not reasonable based on the change of single thermodynamic parameter. However, the fouling in the compressor and turbine cannot directly be observed. In this paper, washing strategy model is proposed. At present, off-line washing criteria about gas turbines are mostly established according to compressors of clean gas turbines and the washing cost is neglected. This model pay attention to economical off-line washing interval based on the principle of minimum mean generalized crank washing cost. For the performance deterioration rate of gas turbine due to fouling, it can be obtained by combining reverse method with optical measuring technology. The washing cost includes running additional cost and shutdown cost. For running additional cost, it includes two aspects. The first running additional cost is the cost of power reduction due to the decrease of mass flow rate. The second running additional cost is the cost of the heat rate increase due to the decrease of gas turbine efficiency. For downtime cost, it is the cost of power loss due to the unit downtime. The calculation result indicates the optimal off-line interval is approximately 80 hours. Compared with traditional washing criteria, the model improved the availability of equipment. Compared with the actual interval, the model improved operation security. Finally, the influence factors such as washing number, shutdown time, and fuel price and degradation rate are analyzed. The result shows the model is greatly influenced by these factors.
Real Time Simulation of a DC Microgrid With Control Schemes for Power Management and Voltage Stabilization
Authors: Kumar Mahesh , Srivastava S. C. , Singh S. N.
Published: October 2015

The concept of a DC Microgrid (DCMG) is a promising option to integrate various non-conventional energy resources in islanded and grid connected modes. The DCMG proposed in this work consists of renewable energy sources, battery energy storage system, and various loads. The control schemes, proposed by the authors in [1], [2], have been utilized for the power management and maintaining the DC grid voltage under different operating scenario, including fault conditions. Before physical installation of the DCMG, it is necessary to simulate it in the real time environment to evaluate its performance. This paper presents the testing, validation, and performance evaluation of the proposed DCMG on Real Time Digital Simulator (RTDS).
Increase of Operational Safety of Tilting-Pad Journal Bearings by Extraction of Hot Oil at the Trailing Edge
Authors: Kukla Sebastian , Buchhorn Nico , Bender Beate
Published: October 2015

A theoretical study is presented with the main objective on the operational safety parameters (minimum film thickness and maximum pad temperature) and thermomechanical deformations of a ø500 mm rocker pad tilting-pad journal bearing (TPJB) for application in large turbo machinery. It can be described by the following specifications: Five pads, 0.23 nominal preload, 60% offset, 56° pad arc angle, 350 mm pad length and 1.28‰ relative bearing clearance. Theoretical investigations are carried out for circumferential speeds up to 78 m/s and static loads up to 3.60 MPa.

The simulation tool simultaneously solves both Reynolds and energy equations for the oil film (3D temperature distribution) on the one hand and computes thermomechanical deformations of the pad on the other hand. The simulations are conducted for a single pad and are supported by boundary conditions taken from experiments. The results with regard to static bearing characteristics and pad deformation show good agreement with experiments.

The impact of axial pad arching on operational safety parameters and load-carrying capacity are shown and compared to experimental results. It is shown that the axial deviation in film thickness Δh can be even higher than the minimum film thickness hmin. This leads to reduced hydrodynamic pressure build-up towards the axial edges and therefore significantly decreased safety parameters or load-carrying capacity.

In order to reduce pad crowning, radial bores through the pad body are modelled to simulate the extraction of hot oil from the trailing edge. In the simulation, the hot oil is used to heat up the back of the pad for a decrease of radial temperature gradients and thus pad arching. It is shown that by extracting 0.4 l/s of hot oil, a decrease in axial pad crowning from Δh = 47μm to Δh = 26μm can be achieved and that this leads to a decrease of 7.8 K in maximum temperature and an increase of 5 μm in minimum film thickness respectively a gain of load-carrying capacity of 0.4–0.6 MPa.
Comprehensive Reduction of Thermal Resistance in Air Cooled Condensers
Authors: Saleh Ahmad , Kapat Jayanta
Published: October 2015

Restriction on water consumption is becoming an increasing problem for the power generation industry. As an alternative both to once-through cooling and to surface condenser/wet-cooling tower combination, utility companies and equipment manufacturers are considering, and even implementing, air-cooled condenser (ACC). However, the industry is quite reluctant to switch over to ACC for three important reasons: (a) lower power output, (b) higher capital cost, and (c) larger physical foot-print, all because of the same reason — it is not as efficient to transfer heat from condensing steam to air as it is to transfer to water. In other words, overall thermal resistance from condensing steam to the ambient air is significantly higher than to cooling water.

To get a clear and full understanding of the heat transfer process occur in air-cooling condenser, Detailed mathematical equations were derived to model the heat transfer process through the fined-tubes of the ACC. The total thermal resistance model was analyzed and investigated to identify the design components with highest affect in the process.

The paper proposes a viable cooling system based on novel heat pipe technology which addresses these problems. This technology employs boiling as the means to store and transfer heat energy. A detailed mathematical set of equations was derived to model the heat pipe thermal resistance. A comparison of the heat transfer performances of the ACC technology and the proposed method is presented.

The proposed cooling system suggests a solution for each of the three components of the thermal resistance, the super-hydrophobic coating of the steam ducts internal surfaces increased the condensing heat transfer rate by an order of magnitude, the proposed design of the heat pipes improved the external heat transfer, and the installation mechanism improves the fin efficiency by eliminating the contact resistance between steam duct and the heat pipe.
Post Mortem of a Feedwater Heater With Drains Cooler Failures
Authors: Svensson Eric , Halcomb D. Chad
Published: October 2015

The Paradise Generation Station Unit 3 is a supercritical fossil plant with a 1,078 MW rated capacity. The #3B feedwater heater (FWH) is a two-zone (condensing and subcooling) horizontal FWH and is the second of four high pressure (HP) FWHs after the boiler feed pump in the “B” string, one of two HP FWH strings (See Figure A2 at the end of this paper for an outline drawing of the heater. The heater has 1447 SA-556-C2 Carbon Steel tubes, 3/4” OD × 0.085 min wall. The heater was built in late 2006/early 2007 and was installed in summer 2007.

After just a few years of operation, the #3B FWH experienced several failures at the entrance to the drain cooler (DC) zone. The #3A FWH, of identical construction and built and installed at the same time, did not show the same level of damage.

In order to determine the failure mechanisms involved, a post-mortem of the heater was performed. This paper shall discuss the post-mortem inspection conducted as well as the suspected and confirmed causes of failure in the heater.
Improvements in the Performance of a Subcooling Zone in a Feedwater Heater With Dual End Plate Design With Water Seal in Between
Authors: Nadig Ranga
Published: October 2015

In a horizontal feedwater heater with a partial length subcooling zone the end plate located at the entrance to the subcooling zone is the only non-welded barrier that prevents the condensing zone steam from entering the subcooling zone. The end plate is usually two or three inches thick and the tube holes in the end plate are drilled to tolerances similar to that of the tubesheet. As the steam from condensing zone tries to enter the subcooling zone it condenses in the tight spaces between the active tube and the tube hole in the end plate forming a liquid barrier that prevents further ingress of steam into the subcooling zone. With usage and wear the gap between the active tube and the tube hole in the end plate increases thereby weakening the liquid barrier. The liquid barrier is completely lost when the tubes are plugged. Steam from condensing zone enters the subcooling zone and disrupts the performance of the subcooling zone, the performance of the feedwater heater and the efficiency of the power plant. This problem is faced by all horizontal feedwater heaters with subcooling zones that are in operation in power plants worldwide.

This loss of performance can be eliminated by employing the patent pending Maarky concept of “dual end plate subcooling zone with a water seal”. The “dual end plate subcooling zone with water seal” concept comprises of two end plates separated by a short distance. The gap between the two end plates is filled with condensate thereby forming a triple barrier to ingress of condensing zone steam into the subcooling zone. The performance of the subcooling zone and the longevity of the heater are preserved.

This paper discusses the design of subcooling zone in present day feedwater heaters, degradation of performance of subcooling zone and the improvements brought about by the patent pending Maarky concept of “dual end plate subcooling zone with water seal”.
Quantitative Study of Photovoltaic Arrays in the Pacific Northwest: Analyzing a Photovoltaic System in Portland Oregon
Authors: Jackson Elliott C. , Lum Jordan S. , Dillon Heather E.
Published: October 2015

This paper describes a quantitative study conducted on the performance of the photovoltaic (PV) system at the University of Portland in Oregon. The objective of the study was to compare the performance to other PV systems in the Pacific Northwest. Data collected over a span of two years was used to determine the maximum and minimum energy production days of the year, to generate average monthly performance and annual energy plots, to observe correlation between outside temperature and the photovoltaic system performance, and to compare actual performance of the system to the expected performance. The greatest energy production day was found to be July 11, 2013 with total energy production of about 35 kWh. The minimum energy production day was found to be January 16, 2013 with total energy production of about 1 kWh. According to initial calculations and analysis, the actual performance of the photovoltaic system reaches an efficiency of around 12.3%. Expected system performance was listed at an estimated rating of 14.9%, indicating a slight reduction from expected performance. From the analysis conducted, the photovoltaic system has been found to be performing close to expectations. Continued analysis of the system will allow for further comparison to other PV systems in the Pacific Northwest.
Design of a 100 kW Concentrated Solar Power on Demand Volumetric Receiver With Integral Thermal Energy Storage Prototype
Authors: Gil Antoni , Codd Daniel S. , Zhou Lei , Trumper David , Campbell Ronald B. , Grange Benjamin , Calvet Nicolas , Armstrong Peter , Slocum Alexander H.
Published: October 2015

A new concept of Thermal Energy Storage (TES) system based on current available technologies is being developed under the framework of the Masdar Institute (MI) and Massachusetts Institute of Technology (MIT) collaborative Flagship Program. The key feature of this concept lies on concentrating sun light directly on the molten salt storage tank, avoiding the necessity of pumping the salts to the top of a tower thereby avoiding thermal losses and pumping and electric tracing needs inherent in most conventional CSP plants.

This Concentrated Solar Power on Demand (CSPonD) volumetric receiver/TES unit prototype will be tested in the existing MI heliostat field and beam down tower in Abu Dhabi (UAE) which will collect and redirect solar energy to an upwards-facing final optical element (FOE). These energy will be concentrated on the aperture of the prototype designed to store 400 kWh of energy allowing 16 hours of continuous production after sunset using Solar Salt (60%NaNO3 + 40%KNO3) as storage material.

The tank is divided in two volumes: one cold in the bottom region, where Solar Salt is at 250 °C and another hot on the upper region, at 550 °C. A moving divider plate with active control separates both volumes. The plate includes mixing enhancement features to help with convection on the hot volume of salts.

It’s expected that results will demonstrate the technical feasibility and economic viability of this concept allowing its scale up at commercial size.
Thermal Performance Enhancement of an Industrial Shell and Tube Heat Exchanger
Authors: Ghaith Fadi A. , Izhar Ahmed S.
Published: October 2015

This paper aims to enhance the thermal performance of an industrial shell-and-tube heat exchanger utilized for the purpose of cooling raw natural gas by means of mixture of Sales gas. The main objective of this work is to provide an optimum and reliable thermal design of a single-shelled finned tubes heat exchanger to replace the existing two- shell and tube heat exchanger due to the space limitations in the plant. A comprehensive thermal model was developed using the effectiveness-NTU method. The shell-side and tube-side overall heat transfer coefficient were determined using Bell-Delaware method and Dittus-Boelter correlation, respectively. The obtained results showed that the required area to provide a thermal duty of 1.4 MW is about 1132 m2 with tube-side and shell-side heat transfer coefficients of 950 W/m2K and 495 W/m2K, respectively. In order to verify the obtained results generated from the mathematical model, a numerical study was carried out using HTRI software which showed a good match in terms of the heat transfer area and the tube-side heat transfer coefficient.
Aeroelastic Impact of a Circumferentially Varying Tip Gap
Authors: Canon David , Kapat Jayanta
Published: October 2015

The tip leakage flow in axial compressors is a significant factor in engine performance and a subject of investigation over the last several decades. Many studies have already shown that the vortices generated by this tip leakage can have a negative impact on the surrounding flow field and overall performance, and lead to excitations as well. This study examines the effect of these vortices on aeroelasticity, specifically, the effect of a circumferentially varying tip gap; such as that produced by casing ovalization.

For this paper, a single passage, structured grid, CFD model of a compressor’s mid-stage rotor-stator configuration was analyzed using StarCCM+’s harmonic balance solver. This was a frequency domain calculation, which provided significant time savings relative to the more conventional time accurate approach. The vibratory results from an Abaqus model were incorporated into the CFD in order to calculate the aerodynamic work. The calculation modeled a circumferentially varying tip gap representative of what is seen in a real engine, and results were compared to solutions from models with circumferentially constant gaps. Furthermore, test data from an industrial gas turbine was utilized in order to recreate realistic levels of tip gap variation, as well as to validate the mechanical model’s vibratory results. The calculations showed that for the gap variation imposed, the work per cycle was increased by 59% relative to a case with constant gaps.
Mitigation of Adverse Effect of False Data Injection in Optimally Controlled Smart Grid
Authors: Ghosal Malini , Rao Vittal
Published: October 2015

The ‘smart grid’ is one of the largest critical infrastructure systems of any nation. Preventing the grid from data integrity attacks is vital for reliable operation of the grid. Various Phasor Measurement Units (PMUs) and other intelligent electronic devices play crucial role in real-time operations of the grid. Control actions are taken based on information received from such devices. However, all these modern measurement systems communicate with the control center via wireless network making them vulnerable to several security threats, data integrity attack being one of them. This paper addresses the issues associated with the injection of malicious data into the measurements. A model based ‘trustiness’ technique has been proposed to mitigate the adverse effect of such attacks in the performance of the electrical power grid. The proposed method has been demonstrated using the IEEE 14-bus test system.
Impact of Blade Cooling on Gas Turbine Performance Under Different Operation Conditions and Design Aspects
Authors: Besharati-Givi Maryam , Li Xianchang
Published: October 2015

The increase of power need raises the awareness of producing energy more efficiently. Gas turbine has been one of the important workhorses for power generation. The effects of parameters in design and operation on the power output and efficiency have been extensively studied. It is well-known that the gas turbine inlet temperature (TIT) needs to be high for high efficiency as well as power production. However, there are some material restrictions with high-temperature gas especially for the first row of blades. As a result blade cooling is needed to help balance between the high TIT and the material limitations. The increase of TIT is also limited by restriction of emissions. While the blade cooling can allow a higher TIT and better turbine performance, there is also a penalty since the compressed air used for cooling is removed from the combustion process. Therefore, an optimal cooling flow may exist for the overall efficiency and net power output. In this paper the relationship between the TIT and amount of cooling air is studied. The TIT increase due to blade cooling is considered as a function of cooling air flow as well as cooling effectiveness. In another word, the increase of the TIT is limited while the cooling air can be increased continuously. Based on the relationship proposed the impact of blade cooling on the gas turbine performance is investigated. Compared to the simple cycle case without cooling, the blade cooling can increase the efficiency from 28.8 to 34.0% and the net power from 105 to 208 MW. Cases with different operation conditions such as pressure ratios as well as design aspects with regeneration are considered. Aspen plus software is used to simulate the cycles.
Application of Improved Real-Valued Genetic Algorithm in Gas Dispatching of Iron and Steel Enterprise
Authors: Su Fuyong
Published: October 2015

Byproduct gas is an important kind of secondary energy generated along with iron and steel products in iron and steel enterprise, which plays an important role in the product process. The use of byproduct gas is not carefully considered, the caloric value doesn’t always match, and the amount of gas is not correctly used, and the fact of gas emission still exists, which is a waste of energy source, and will raise the problem of environmental pollution, of course. Based on the situations above, we have studied the current situation of an iron and steel enterprise, and built the objective model for the optimal use of the gas, and set the constraints accordingly. Finally, based on the concept of Ant Colony Algorism, we improved the algorism to solve our model, and achieved the optimal program, which is an evidence for the energy use.
Design of a Multiphase Pump Test Laboratory Allowing to Perform Flow Visualization and Instability Analysis
Authors: Serena Alberto , Bakken Lars E.
Published: October 2015

This paper describes the design and construction of an advanced laboratory setup allowing the study of a multiphase pump model.

The main objective is to relate the pump behaviour and instabilities to flow phenomena in the hydraulic channels, studying the machine ability to handle with multiphase flows and transient conditions and the influence of operating parameters (pump speed, flow rates, broad range of gas-liquid compositions, and suction pressure) on the machine performance and operating range, described through performance maps.

To perform this study, different analysis techniques will be employed and compared: experimental test results, analytical model predictions and numerical tool validation. The key role is played by the accurate visual investigation of the main parameters characterizing multiphase flow (bubble size and shape, liquid film thickness, etc.); gas/liquid interface, flow morphology and flow pattern transition are observed and will serve later to validate the prediction models. In addition, the measurement of dynamic pressure fluctuations helps understanding the transient nature of two-phase flow phenomena.

The test facility allows different fine adjustments, to study the effects of upstream flow conditions and clearance sizes on performance and stability.

This first paper focuses on the laboratory test facility, reporting the design process and the results of the experimental work.
Gay Pride on Stolen Land: Homonationalism and Settler Colonialism at the Vancouver Winter Olympics
Authors: Sykes Heather
Published: October 2015

A new form of sporting settler homonationalism emerged in the Pride Houses at the 2010 Vancouver Winter Olympics. For the first time ever, Pride Houses were set up where gay and lesbian supporters watched and celebrated the Olympic events. Drawing on poststructuralism, queer and settler colonial studies, the paper analyzes how the Pride Houses were based on settler colonial discourses about participation and displacement. A settler discourse about First Nations and Two-Spirit participation in the Pride Houses allowed gay and lesbian Canadian settlers to both remember and forget the history of settlement. Another settler discourse took for granted the displacement of Two-Spirit youth from their community center and Indigenous people from their traditional territories in order for the Olympics and the Pride Houses to take place. The paper suggests that queering settler politics in sport means confronting, rather than disavowing, colonialism and challenging homonational forms of gay and lesbian inclusion in sport mega- events.
“You Go Girl!”: Twitter and Conversations About Sport Culture and Gender
Authors: Sanderson Jimmy , Gramlich Kelly
Published: October 2015

On August 5, 2014, the San Antonio Spurs of the National Basketball Association (NBA) made history by hiring Becky Hammon as the first full-time, paid assistant coach in mainstream North American sport. Hammon’s hiring provided an impetus to examine how Twitter opened avenues for discussions around gender in sport culture to generate and permeate. Using Radian6 social media extraction software a sample of 1,434 tweets were obtained. A thematic analysis was conducted and revealed three themes: (a) opening the space for conversation; (b) offering evidence of sport cultural change; and (c) expressing resistance to sport cultural change. The results suggest that Twitter functions as a space where aspects of sport culture are disseminated and contested in ways that transcend traditional media’s treatment of these topics. As people share content that is personally meaningful and relevant and participate in shared conversations about sport cultural issues, it invites them to engage in active citizenry through joining in these discussions.
“The Mad Russian”: Representations of Alexander Ovechkin and the Creation of Canadian National Identity
Authors: Allain Kristi A.
Published: October 2015

The paper argues that the Canadian media’s representations of National Hockey League (NHL) player Alexander Ovechkin work to locate Canadian national identity through its contrasts with the hockey superstar. Even though the press celebrates Ovechkin as a challenge to Cold War understandings of Soviet hockey players as lacking passion and heart as well as physical play, they also present Ovechkin as a ‘dirty’ hockey player who is wild and out of control. By assessing reports from two Canadian national newspapers, the Globe and Mail and the National Post, from 2009 to 2012, and comparing these documents to reports on two Cold War hockey contests, the 1972 Summit Series and the 1987 World Junior Hockey Championships, this article demonstrates how the Canadian media’s paradoxical representations of Ovechkin break with and rearticulate Cold War understandings of Russian/Soviet athletes. Furthermore, when the press characterizes Ovechkin and other Russian hockey players as wild, unpredictable and out-of-control, they produce Canadian players as polite, disciplined and well-mannered. Through these opposing representations, the media helps to locate Canadian national hockey identity within a frame of appropriate masculine expression.
Pharmacodynamics of Isavuconazole in a Dynamic
In Vitro
Model of Invasive Pulmonary Aspergillosis
Authors: Box Helen , Livermore Joanne , Johnson Adam , McEntee Laura , Felton Timothy W. , Whalley Sarah , Goodwin Joanne , Hope William W.
Published: October 2015

Isavuconazonium sulfate is a novel triazole prodrug that has been recently approved for the treatment of invasive aspergillosis by the FDA. The active moiety (isavuconazole) has a broad spectrum of activity against many pathogenic fungi. This study utilized a dynamic
in vitro
model of the human alveolus to describe the pharmacodynamics of isavuconazole against two wild-type and two previously defined azole-resistant isolates of
Aspergillus fumigatus
. A human-like concentration-time profile for isavuconazole was generated. MICs were determined using CLSI and EUCAST methodologies. Galactomannan was used as a measure of fungal burden. Target values for the area under the concentration-time curve (AUC)/MIC were calculated using a population pharmacokinetics-pharmacodynamics (PK-PD) mathematical model. Isolates with higher MICs required higher AUCs in order to achieve maximal suppression of galactomannan. The AUC/MIC targets necessary to achieve 90% probability of galactomannan suppression of <1 were 11.40 and 11.20 for EUCAST and CLSI, respectively.
In Vivo
Synergy of Amphotericin B plus Posaconazole in Murine Aspergillosis
Authors: Martin-Vicente Adela , Capilla Javier , Guarro Josep
Published: October 2015

Aspergillus fumigatus
is the main mold causing invasive fungal infection that shows high mortality rates. Therapeutic failure and the increase in drug resistance make it necessary to explore alternative treatments for this infection. We have evaluated the efficacy of amphotericin B at 0.8 mg/kg or 0.3 mg/kg of body weight combined with 40 mg/kg of posaconazole against three
A. fumigatus
isolates in a murine model of disseminated infection. The combination of the polyene and the azole led to a greater increase in survival and a significantly greater reduction in tissue burden than monotherapies.
Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication
Authors: Merino-Ramos Teresa , Vázquez-Calvo Ángela , Casas Josefina , Sobrino Francisco , Saiz Juan-Carlos , Martín-Acebes Miguel A.
Published: October 2015

West Nile virus (WNV) is a neurotropic flavivirus transmitted by the bite of mosquitoes that causes meningitis and encephalitis in humans, horses, and birds. Several studies have highlighted that flavivirus infection is highly dependent on cellular lipids for virus replication and infectious particle biogenesis. The first steps of lipid synthesis involve the carboxylation of acetyl coenzyme A (acetyl-CoA) to malonyl-CoA that is catalyzed by the acetyl-CoA carboxylase (ACC). This makes ACC a key enzyme of lipid synthesis that is currently being evaluated as a therapeutic target for different disorders, including cancers, obesity, diabetes, and viral infections. We have analyzed the effect of the ACC inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) on infection by WNV. Lipidomic analysis of TOFA-treated cells confirmed that this drug reduced the cellular content of multiple lipids, including those directly implicated in the flavivirus life cycle (glycerophospholipids, sphingolipids, and cholesterol). Treatment with TOFA significantly inhibited the multiplication of WNV in a dose-dependent manner. Further analysis of the antiviral effect of this drug showed that the inhibitory effect was related to a reduction of viral replication. Furthermore, treatment with another ACC inhibitor, 3,3,14,14-tetramethylhexadecanedioic acid (MEDICA 16), also inhibited WNV infection. Interestingly, TOFA and MEDICA 16 also reduced the multiplication of Usutu virus (USUV), a WNV-related flavivirus. These results point to the ACC as a druggable cellular target suitable for antiviral development against WNV and other flaviviruses.
Bioassay for Determining Voriconazole Serum Levels in Patients Receiving Combination Therapy with Echinocandins
Authors: Siopi Maria , Neroutsos Efthymios , Zisaki Kalliopi , Gamaletsou Maria , Pirounaki Maria , Tsirigotis Panagiotis , Sipsas Nikolaos , Dokoumetzidis Aristides , Goussetis Evgenios , Zerva Loukia , Valsami Georgia , Meletiadis Joseph
Published: October 2015

Voriconazole levels were determined with high-performance liquid chromatography (HPLC) and a microbiological agar diffusion assay using a
Candida parapsilosis
isolate in 103 serum samples from an HPLC-tested external quality control program (
n
= 39), 21 patients receiving voriconazole monotherapy (
n
= 39), and 7 patients receiving combination therapy (
n
= 25). The results of the bioassay were correlated with the results obtained from the external quality control program samples and with the HPLC results in sera from patients on voriconazole monotherapy and on combination therapy with an echinocandin (Spearman's rank correlation coefficient [
r
s
], > 0.93; mean ± standard error of the mean [SEM] % difference, <12% ± 3.8%).
In Vitro
Activity of Ceftaroline against Staphylococcus aureus Isolated in 2012 from Asia-Pacific Countries as Part of the AWARE Surveillance Program
Authors: Biedenbach Douglas J. , Alm Richard A. , Lahiri Sushmita D. , Reiszner Edina , Hoban Daryl J. , Sahm Daniel F. , Bouchillon Samuel K. , Ambler Jane E.
Published: October 2015

Ceftaroline, the active metabolite of the prodrug ceftaroline-fosamil, is an advanced-generation cephalosporin with activity against methicillin-resistant
Staphylococcus aureus
(MRSA). This investigation provides
in vitro
susceptibility data for ceftaroline against 1,971
S. aureus
isolates collected in 2012 from seven countries (26 centers) in the Asia-Pacific region as part of the Assessing Worldwide Antimicrobial Resistance and Evaluation (AWARE) program. Broth microdilution as recommended by the CLSI was used to determine susceptibility. In all, 62% of the isolates studied were MRSA, and the ceftaroline MIC
90
for all
S. aureus
isolates was 2 μg/ml (interpretive criteria: susceptible, ≤1 μg/ml). The overall ceftaroline susceptibility rate for
S. aureus
was 86.9%, with 100% of methicillin-sensitive
S. aureus
isolates and 78.8% of MRSA isolates susceptible to this agent. The highest percentages of ceftaroline-nonsusceptible MRSA isolates came from China (47.6%), all of which showed intermediate susceptibility, and Thailand (37.1%), where over half (52.8%) of isolates were resistant to ceftaroline (MIC, 4 μg/ml). Thirty-eight ceftaroline-nonsusceptible isolates (MIC values of 2 to 4 μg/ml) were selected for molecular characterization. Among the isolates analyzed, sequence type 5 (ST-5) was the most common sequence type encountered; however, all isolates analyzed from Thailand were ST-228. Penicillin-binding protein 2a (PBP2a) substitution patterns varied by country, but all isolates from Thailand had the Glu
239
Lys substitution, and 12 of these also carried an additional Glu
447
Lys substitution. Ceftaroline-fosamil is a useful addition to the antimicrobial agents that can be used to treat
S. aureus
infections. However, with the capability of this species to develop resistance to new agents, it is important to recognize and monitor regional differences in trends as they emerge.
Memory B Cells Encode Neutralizing Antibody Specific for Toxin B from the Clostridium difficile Strains VPI 10463 and NAP1/BI/027 but with Superior Neutralization of VPI 10463 Toxin B
Authors: Devera T. Scott , Lang Gillian A. , Lanis Jordi M. , Rampuria Pragya , Gilmore Casey L. , James Judith A. , Ballard Jimmy D. , Lang Mark L.
Published: October 2015

Secreted toxin B (TcdB) substantially contributes to the pathology observed during
Clostridium difficile
infection. To be successfully incorporated into a vaccine, TcdB-based immunogens must stimulate the production of neutralizing antibody (Ab)-encoding memory B cells (Bmem cells). Despite numerous investigations, a clear analysis of Bmem cellular responses following vaccination against TcdB is lacking. B6 mice were therefore used to test the ability of a nontoxigenic C-terminal domain (CTD) fragment of TcdB to induce Bmem cells that encode TcdB-neutralizing antibody. CTD was produced from the historical VPI 10463 strain (CTD1) and from the hypervirulent strain NAP1/BI/027 (CTD2). It was then demonstrated that CTD1 induced strong recall IgG antibody titers, and this led to the development of functional Bmem cells that could be adoptively transferred to naive recipients. Bmem cell-driven neutralizing Ab responses conferred protection against lethal challenge with TcdB1. Further experiments revealed that an experimental adjuvant (Imject) and a clinical adjuvant (Alhydrogel) were compatible with Bmem cell induction. Reactivity of human Bmem cells to CTD1 was also evident in human peripheral blood mononuclear cells (PBMCs), suggesting that CTD1 could be a good vaccine immunogen. However, CTD2 induced strong Bmem cell-driven antibody titers, and the CTD2 antibody was neutralizing
in vitro
, but its protection against lethal challenge with TcdB2 was limited to delaying time to death. Therefore, CTD from different
C. difficile
strains may be a good immunogen for stimulating B cell memory that encodes
in vitro
neutralizing Ab but may be limited by variable protection against intoxication
in vivo
.
Gliding Direction of Mycoplasma mobile
Authors: Morio Hanako , Kasai Taishi , Miyata Makoto
Published: October 2015

Mycoplasma mobile
glides in the direction of its cell pole by a unique mechanism in which hundreds of legs, each protruding from its own gliding unit, catch, pull, and release sialylated oligosaccharides fixed on a solid surface. In this study, we found that 77% of cells glided to the left with a change in direction of 8.4° ± 17.6° μm
−1
displacement. The cell body did not roll around the cell axis, and elongated, thinner cells also glided while tracing a curved trajectory to the left. Under viscous conditions, the range of deviation of the gliding direction decreased. In the presence of 250 μM free sialyllactose, in which the binding of the legs (i.e., the catching of sialylated oligosaccharides) was reduced, 70% and 30% of cells glided to the left and the right, respectively, with changes in direction of ∼30° μm
−1
. The gliding ghosts, in which a cell was permeabilized by Triton X-100 and reactivated by ATP, glided more straightly. These results can be explained by the following assumptions based on the suggested gliding machinery and mechanism: (i) the units of gliding machinery may be aligned helically around the cell, (ii) the legs extend via the process of thermal fluctuation and catch the sialylated oligosaccharides, and (iii) the legs generate a propulsion force that is tilted from the cell axis to the left in 70% and to the right in 30% of cells.

IMPORTANCE
Mycoplasmas are bacteria that are generally parasitic to animals and plants. Some
Mycoplasma
species form a protrusion at a pole, bind to solid surfaces, and glide. Although these species appear to consistently glide in the direction of the protrusion, their exact gliding direction has not been examined. This study analyzed the gliding direction in detail under various conditions and, based on the results, suggested features of the machinery and the mechanism of gliding.
Donohue syndrome and use of continuous subcutaneous insulin pump therapy
Authors: Huggard Dean , Stack Tom , Satas Saulius , O Gorman Clodagh
Published: October 2015

Donohue syndrome is a rare autosomal recessive condition caused by severe loss-of-function mutations in the insulin receptor (INSR) gene. The diagnosis is made on clinical, biochemical and genetic grounds. Mutations are found on chromosome 19p13.2, and code for mutations in the INSR gene. Treatment is challenging and often unsuccessful, and relies on maintaining normoglycaemia and avoiding fasting; in some patients, recombinant human insulin-like growth factor (rhIGF-1) has been trialled. The prognosis is poor, with most babies dying in infancy. Ethically, it is important to consider the benefit versus burden of treatment, the quality of life of the surviving patient and the parents’ wishes, when making decisions regarding withholding or withdrawing care.
Severe acute measles pneumonitis: virus isolation in bronchoalveolar lavage fluid
Authors: Suter Cosima , Buergi Urs , Eigenmann Katja , Franzen Daniel
Published: October 2015

In the past few years, several endemic outbreaks of measles have been recognised, not only in children but also in adults, with severe and, occasionally, even fatal complications, possibly due to delayed diagnosis of the disease in adult medicine and decreasing vaccination rates. Furthermore, the treatment consists of supportive measures only. We present a case of severe measles pneumonitis in a 42-year-old man, a travel returnee, proven by direct virus isolation with PCR from bronchoalveolar lavage fluid. CT findings and pulmonary function testing revealed features of obstructive bronchiolitis; the patient was successfully treated with corticosteroids. He fully recovered, and lung function measurement returned to normal values. We conclude that acute measles can present as obstructive bronchiolitis and may be successfully treated with corticosteroids.
Laparoscopic treatment of intestinal obstruction caused by an uncommon congenital band
Authors: Jerraya Hichem , Khalfallah Mehdi , Gaja Ali , Dziri Chadli
Published: October 2015

Congenital bands represent a rare cause of small bowel obstruction. We report a case of intestinal obstruction caused by an uncommon form of congenital band in a 16-year-old girl. The diagnosis was strongly evoked preoperatively by CT scan and the intestinal obstruction was successfully treated using a laparoscopic approach.
What the mind does not know, the eyes do not see: a rare congenital fusion of the odontoid process to the atlantal hemiarch
Authors: Sureisen Mariapan , Achannan Ramanand , Chong Kuan Chon , Wong Chung Chek
Published: October 2015

Congenital spinal fusion of an odontoid process to an atlantal hemiarch is very rare. The unfamiliarity of the medical fraternity with this congenital malformation can easily be mistaken for an acute fracture, chronic infection or inflammatory disease. We present our experience of managing an adult who presented with neck pain after a motor vehicle accident. Radiological investigation revealed congenital fusion of the odontoid process to the atlantal hemiarch. The prevalence, embryology and clinical significance of this anomaly are discussed. As the natural progression of this anomaly is not well documented, we suggest periodic follow-up to monitor the progression of degenerative changes and instability of the occipitoatlantal junction.
Relationship between cardiovascular health score and year-to-year blood pressure variability in China: a prospective cohort study
Authors: An Shasha , Bao Minghui , Wang Yang , Li Zhifang , Zhang Wenyan , Chen Shuohua , Li Junjuan , Yang Xinchun , Wu Shouling , Cai Jun
Published: October 2015

Objectives

On the basis of cardiovascular health factors and behaviours, the American Heart Association proposed the Cardiovascular Health Score (CHS). It has been widely used to estimate the cardiovascular health status of individuals. The aim of this study was to investigate the relationship between CHS and year-to-year blood pressure variability (BPV).

Design

Prospective cohort study.

Settings

We stratified participants into two groups by gender: first group, female group; second group, male group. The relationship between CHS and year-to-year blood pressure variability were analysed.

Participants

A total of 41 613 individuals met the inclusion criteria (no history of stroke, transient ischaemic attack, myocardial infarction, malignant tumour or atrial fibrillation) and had complete blood pressure data.

Results

The coefficient of the variation of systolic blood pressure (SCV) was 8.33% in the total population and 8.68% and 8.22% in female and male groups, respectively (p<0.05). Multivariable linear regression analysis revealed that higher CHS was inversely associated with increasing year-to-year BPV, which persisted after adjusting for baseline systolic blood pressure and other risk factors. Each SD increase in CHS could lead to a 0.016SD decrease in SCV (p<0.05).

Conclusions

In summary, CHS was inversely related to year-to-year BPV, which suggested that a healthy lifestyle may contribute to better blood pressure management.
Berberine Increases Doxorubicin Sensitivity by Suppressing STAT3 in Lung Cancer
Authors: Zhu Ting , Li Lin-Lin , Xiao Guang-Fa , Luo Qi-Zhi , Liu Qiu-Zheng , Yao Kai-Tai , Xiao Guang-Hui
Published: October 2015

Berberine (BBR), an alkaloid component isolated from Chinese medicinal herb Huang Lian, has aroused broad interests for its antitumor effect in recent years. The signal transducer and activator of transcription 3 (STAT3), plays critical roles in malignant transformation and progression and was found to be constitutively activated in a variety of human cancers. In this study, we show that BBR inhibited cell proliferation, induced apoptosis, and suppressed tumor spheroid formation of lung cancer cell lines. These effects were correlated with BBR-mediated suppression of both phosphorylated and total levels of STAT3 protein. Furthermore, BBR promoted STAT3 degradation by enhancing ubiquitination. Importantly, we demonstrated that BBR was able to inhibit doxorubicin (DOX)-mediated STAT3 activation and sensitize lung cancer cells to the cytotoxic effect of DOX treatment. Given that BBR is widely used in clinic with low toxicity, our results are potentially important for the development of a novel combinatorial therapy with BBR and DOX in the treatment of lung cancer.
Effect of magnesium on relaxation frequency of Ni–Zn nanoferrites
Authors: Ganga Swamy D. R. S. , Chaitanya Varma M. , Bharadwaj S. , Sambasiva Rao K. , Rao K. H.
Published: October 2015

[Formula: see text] (x = 0, 0.4, 0.8, 0.10, 0.12 and 0.16) samples have been synthesized by sol–gel method using polyvinyl alcohol (PVA) as chelating agent. The synthesized samples were sintered at 1000[Formula: see text]C for 1 h. The X-ray diffraction (XRD) confirms single phase spinel structure and scanning electron microscope (SEM) confirms the uniform grain with increasing grain growth with increase concentration of magnesium (Mg) (x). A slight increase in saturation magnetization (VSM) has been observed for low concentrations of magnesium which disappear for higher concentrations of magnesium [Formula: see text] in these materials. Decrease in room temperature DC resistivity with magnesium concentration has been attributed to grain growth. The permeability measured for the ferrites exhibits high permeability for increase in the magnesium content. The permeability behavior is understood on the basis of domain wall contribution and grain growth. Frequency dependence of permeability as measured suggests that the suitability of all the samples for high frequency core applications as the operating frequency lies beyond 110 MHz.