bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidermolysis Bullosa Simplex with Mottled Pigmentation Due to a Rare Keratin 5 Mutation: Cutaneous Findings in Infancy
Authors: Geller Lauren , Kristal Leonard , Morel Kimberly D.
Published: July 2013

Epidermolysis bullosa simplex with mottled pigmentation (EBS‐MP) is an autosomal dominant inherited blistering skin disease characterized by nonscarring blistering and reticulated hyperpigmentation. It is most commonly due to a heterozygous point mutation, P25L, in the nonhelical V1 domain of keratin 5 (KRT5). Here we present a case of EBS‐MP with early onset of reticulated hyperpigmentation during infancy due to a rare 1649delG mutation in the V2 domain of KRT5.
USING SEMI‐AUTOMATED SEGMENTATION OF COMPUTED TOMOGRAPHY DATASETS FOR THREE‐DIMENSIONAL VISUALIZATION AND VOLUME MEASUREMENTS OF EQUINE PARANASAL SINUSES
Authors: Brinkschulte Markus , Bienert‐Zeit Astrid , Lüpke Matthias , Hellige Maren , Staszyk Carsten , Ohnesorge Bernhard
Published: July 2013

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three‐dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2–25 years, were analyzed by the use of separate semi‐automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi‐automated segmentation of CT‐datasets improved understanding of this anatomically challenging region.
Dual-Solution and Choked Flow Treatment in a Streamline Curvature Throughflow Solver
Authors: Tiwari Prashant , Stein Alex , Lin Yu-Liang
Published: July 2013

In most turbomachinery design systems, streamline curvature based throughflow calculations make the backbone of aero design process. The fast, reliable, and easy to understand solution is especially useful in performing several multistage design iterations in a short period of time. Although the streamline curvature based technique enjoys many benefits for subsonic applications, there are some challenges for transonic and supersonic flow applications, which is the focus of this paper. In this work, it is concluded that three key improvements are required to handle transonic flows in a streamline curvature throughflow solver. These are (1) the ability to overcome dual sub and supersonic solutions and guide the solver towards a supersonic flow solution where applicable; (2) a suitable technique to calculate the streamline curvature gradient term, which can avoid singularity at sonic meridional Mach number and high gradient values in transonic flows; and (3) a suitable technique to handle choked flow in the turbomachinery flowpath. Solution procedures for “dual-solution” and choked flow treatment are new and developed as part of this work. However, a procedure for calculating streamline curvature gradient is leveraged from earlier work done by Denton (1978, “Throughflow Calculations for Transonic Axial Flow Turbines,” Trans. ASME, 100, pp. 212–218) and Came (1995, “Streamline Curvature Throughflow Analysis,” VDI-Ber., 1185, p. 291). Implementation of these improvements is performed in a streamline curvature based throughflow solver. Numerical improvements presented here have been tested for a range of compressor and turbine cases (both subsonic and supersonic). It is shown that the numerical improvements presented in this paper resulted in an enhanced version of the streamline curvature throughflow solver. The new code produces consistent solutions for subsonic applications with no sacrifice in the accuracy of the solver. However, considerable robustness improvements are achieved for transonic turbine cases.
Numerical Modeling of Seabed Response to Combined Wave-Current Loading
Authors: Zhang J.-S. , Zhang Y. , Zhang C. , Jeng D.-S.
Published: July 2013

In this paper, a numerical model is developed to study the dynamic response of a porous seabed to combined wave-current loadings. While the Reynolds-averaged Navier–Stokes equations with k-ε turbulence closure scheme and internal wave-maker function are solved for the phenomenon of wave-current interaction, Biot's poro-elastic “u-p” model is adopted for the seabed response. After validated by the laboratory measurements, this model is applied for the investigation of the effects of waves and currents on the wave-current induced pore pressures. Furthermore, the effects of currents on maximum liquefaction depths of a porous seabed is examined, and it is concluded that the opposite currents will increase the liquefaction depth up to 30% of that without currents.
Numerical Investigation of a Film-Cooling Flow Structure: Effect of Crossflow Turbulence
Authors: Ziefle Jörg , Kleiser Leonhard
Published: July 2013

Numerical simulation results using large-eddy simulation of a flow configuration relevant to the film cooling of turbine blades are presented. The flow configuration and the simulation parameters are chosen according to an experiment from literature, in which a hot turbulent crossflow over a flat plate is cooled by fluid issuing from a large isobaric plenum through a short inclined circular nozzle. Special attention is paid to the flow structure within the jet nozzle and the mixing region, as well as to the effect of the crossflow fluctuations thereon. To this end, the numerical results with the turbulent crossflow are compared to our previous data obtained with a steady mean-turbulent inflow profile. While the flow inside the nozzle is very similar for the two cases, large differences occur in the mixing region, where a much enhanced spreading of the coolant is observed with the turbulent crossflow. Consequently, the good agreement of the film-cooling efficiencies with the experimental data for the turbulent-crossflow case is contrasted by large deviations with the stationary inflow due to the lack of crossflow fluctuations.
Detonation and Transition to Detonation in Partially Water-Filled Pipes
Authors: Bitter Neal P. , Shepherd Joseph E.
Published: July 2013

Detonations and deflagration-to-detonation transition (DDT) are experimentally studied in horizontal pipes which are partially filled with water. The gas layer above the water is stoichiometric hydrogen–oxygen at 1 bar. The detonation wave produces oblique shock waves in the water, which focus at the bottom of the pipe due to the curvature of the walls. This results in peak pressures at the bottom of the pipe that are 4–6 times greater than the peak detonation pressure. Such pressure amplification is measured for water depths of 0.25, 0.5, 0.75, 0.87, and 0.92 pipe diameters. Focusing of the oblique shock waves is studied further by measuring the circumferential variation of pressure when the water depth is 0.5 pipe diameters, and reasonable agreement with theoretical modeling is found. Despite the local pressure amplification due to shock focusing, peak hoop strains decreased with increasing water depth. Failure of the detonation wave was not observed, even for water depths as high as 0.92 pipe diameters. Likewise, transition to detonation occurred for every water height.
A Numerical Study of the Impact of Wavy Walls on Steady Fluid Flow Through a Curved Tube
Authors: Prince Chekema , Gu Mingyao , Peterson Sean D.
Published: July 2013

In this paper, we discuss the impact of a wavy-walled pipe cross-section on steady flow in a curved tube at moderate Dean numbers and small tube radius-to-radius-of-curvature ratios. Parameters investigated include the protrusion height, the number of protrusions around the tube circumference, and the pipe curvature. This work extends a previous analytical investigation that employed a double perturbation expansion to elucidate the flow field as a function of these parameters. Due to the rapid growth in the solution complexity as the number of terms in each expansion increases, the analytical work is relegated to small wall perturbations and low Dean numbers. These barriers are removed in the present study by numerically solving the Navier–Stokes equations at Dean numbers up to 2500. The impact on the axial and secondary flow structures are emphasized, along with the resulting wall shear stress distributions.
Current Stimuli That Provide Membrane Voltage Tracking in a Six Dimensional Neuron Model
Authors: Koelling Melinda E. , Miller Damon A. , Ellinger Michael , Severance Frank L. , Stahl John
Published: July 2013

Optimization techniques have been applied to neuron models for a variety of purposes, including control of neuron firing rates and minimizing input stimulus current magnitudes. Optimal control is used to minimize a quantity of interest; often, the time or energy needed to complete an objective. Rather than attempting to control or modify neuron dynamics, this paper demonstrates that optimal control can be used to obtain an optimal input stimulus current i*(t) which causes a six dimensional Hodgkin–Huxley type neuron model to approximate a specified reference membrane voltage. The reference voltages considered in this paper consist of one or more action potentials as evoked by an input current i(t). In the described method, the user prescribes a balance of low squared integral of input stimulus current (input stimulus “energy”) and accurate tracking of the original reference voltage. In a previous work, the authors applied this approach to a reduced order neuron model. This paper demonstrates the applicability of this technique to biologically plausible higher dimensional conductance based neuron models. For each investigated neuron response, the method discovered optimal input stimuli current i*(t) having a lower energy than the original i(t), while still providing accurate tracking of the reference voltage.
Friction Factor for Transient Flow in Transverse Corrugated Pipes
Authors: Popiel C. O. , Kozak M. , Małecka J. , Michalak A.
Published: July 2013

Since the pressure losses in corrugated pipe flows are very high, their friction factor was investigated experimentally. Results of measurements of friction factor in laminar to turbulent transition zone of water flow in transverse corrugated pipes having regular roughness of approximately sinusoidal type are presented. The friction factors for four investigated commercially available pipes are increasing asymptotically to some maximum values with rising Reynolds number. Results were obtained for the corrugation depth to minimum diameter ratios, 0.103 ≤ e/d ≤ 0.148 and for the relative corrugation pitch, 0.462 ≥ P/d ≥ 0.270.
Large-Eddy Simulation for Turbulent Heat Transfer
Authors: Tafti Danesh K.
Published: July 2013

The paper gives an overview of different components of conducting large-eddy simulations (LES) for convective heat transfer in practical applications. Subgrid stress models, wall models, and the generation of inlet turbulent boundary conditions are highlighted. For application to complex high Reynolds number flows, a two-layer LES wall model is used together with a synthetic eddy method (SEM) for generating turbulent inlet conditions for developing flows. Representative results highlighting LES predictions are given in a dimpled fin arrangement relevant to compact heat exchangers, in a simulated leading edge film cooling geometry, and in a developing ribbed duct and 180 deg turn relevant to turbine blade cooling. The use of LES wall modeling with the SEM is shown in an experimental can combustor with swirl, and finally a simulation which combines Reynolds-averaged Navier–Stokes (RANS) with wall modeled LES and SEM to predict combustor linear heat transfer is highlighted. It is shown that the combined use of these techniques can reduce computational time by at least an order of magnitude for developing flows. In all cases, predictions of mean turbulent quantities and heat transfer coefficients compare favorably with experiments.
Applications of Heat Transfer Fundamentals to Fire Modeling
Authors: Ezekoye O. A. , Hurley M. J. , Torero J. L. , McGrattan K. B.
Published: July 2013

The fire industry relies on fire engineers and scientists to develop materials and technologies used to either resist, detect, or suppress fire. While combustion processes are the drivers for what might be considered to be fire phenomena, it is heat transfer physics that mediate how fire spreads. Much of the knowledge of fire phenomena has been encapsulated and exercised in fire modeling software tools. Over the past 30 years, participants in the fire industry have begun to use fire modeling tools to aid in decision making associated with design and analysis. In the rest of this paper we will discuss what the drivers have been for the growth of fire modeling tools; the types of submodels incorporated into such tools; the role of model verification, validation, and uncertainty propagation in these tools; and possible futures for these types of tools to best meet the requirements of the user community. Throughout this discussion, we identify how heat transfer research has supported and aided the advancement of fire modeling.
On the Role of Leading-Edge Bumps in the Control of Stall Onset in Axial Fan Blades
Authors: Corsini Alessandro , Delibra Giovanni , Sheard Anthony G.
Published: July 2013

Taking a lead from the humpback whale flukes, characterized by a series of bumps that result in a sinusoidal-like leading edge, this paper reports on a three-dimensional numerical study of sinusoidal leading edges on cambered airfoil profiles. The turbulent flow around the cambered airfoil with the sinusoidal leading edge was computed at different angles of attack with the open source solver OpenFOAM, using two different eddy viscosity models integrated to the wall. The reported research focused on the effects of the modified leading edge in terms of lift-to-drag performance and the influence of camber on such parameters. For these reasons a comparison with a symmetric airfoil is provided. The research was primarily concerned with the elucidation of the fluid flow mechanisms induced by the bumps and the impact of those mechanisms on airfoil performance, on both symmetric and cambered profiles. The bumps on the leading edge influenced the aerodynamic performance of the airfoil, and the lift curves were found to feature an early recovery in post-stall for the symmetric profile with an additional gain in lift for the cambered profile. The bumps drove the fluid dynamic on the suction side of the airfoil, which in turn resulted in the capability to control the separation at the trailing edge in coincidence with the peak of the sinusoid at the leading edge.
Size Effect Law and Critical Distance Theories to Predict the Nominal Strength of Quasibrittle Structures
Authors: Maimí Pere , González Emilio V. , Gascons Narcís , Ripoll Lluís
Published: July 2013

The design of structures with a nonuniform stress field is of great industrial interest. The ability of the size effect law and critical distance theories to predict the nominal strength of notched and open hole specimens is analyzed in the present paper. The results obtained with these methods are compared with the solution of the problem computed, taking into account the material cohesive law. A conclusion of this paper is that the role of the critical fracture energy in determining the structural strength is negligible, except in large cracked structures. For unnotched structures of any size and for small cracked structures, the key parameter is the initial part of the softening cohesive law. This allows us to define design charts that relate the structural strength to a specimen size normalized with respect to a material characteristic length.
Two-Phase Flow-Induced Forces on Piping in Vertical Upward Flow: Excitation Mechanisms and Correlation Models
Authors: Giraudeau M. , Mureithi N. W. , Pettigrew M. J.
Published: July 2013

Momentum variation in two-phase flow generates significant low frequency forces, capable of producing unwanted and destructive vibrations in nuclear or petroleum industries. Two-phase flow-induced forces in piping were previously studied over a range of diameters from 6 mm to 70 mm in different piping element geometries, such as elbows, U-bends, and tees. Dimensionless models were then developed to estimate the rms forces and generate vibration excitation force spectra. It was found that slug flow generates the largest forces due to the large momentum variation between Taylor bubbles and slugs. The present study was conducted with a 52 mm diameter U-bend tube carrying a vertical upward flow. Two-phase flow-induced forces were measured. In addition, two-phase flow parameters, such as the local void fraction, bubble size and velocity, and slug frequency were studied to understand the relationship between the force spectra and the two-phase flow patterns. A new two-phase flow pattern map, based on existing transition models and validated using our own local void fraction measurements and force spectra, is proposed. This paper also presents a comparison of the present dimensionless forces with those of previous studies, thus covers a wide range of geometries and Weber numbers. Finally, a dimensionless spectrum is proposed to correlate forces with large momentum variations observed for certain flow patterns.
Mathematical Modeling and Parametric Study of a Continuous Solar Desalination System
Authors: Rahimi Amir , Movassagh Elias
Published: July 2013

A mathematical model is presented to analyze the performance of a counter-current solar desalination system. Besides, the heat transfer equations, the mass transfer is also considered to improve the model precision. A new approach is used for analyzing the radiative heat transfer in these systems. A low enough value for feed flow rate, a moderate value for glass temperature, taking the advantage of high flux at the appropriate time and appropriate insulation of the floor could effectively increase productivity. The system length is also a significant parameter. The model can be sufficiently extended for other continuous solar desalination systems.
Experimental Characterization of Slug Flow on Solid Particle Transport in a 1 Deg Upward Inclined Pipeline
Authors: Goharzadeh Afshin , Rodgers Peter , Wang Liang
Published: July 2013

This paper presents an experimental investigation on the influence of hydraulic and two phase (gas-liquid) flows on sand dune transportation resulting from a stationary flatbed, for horizontal and 1 deg upward pipe inclination. For gas-liquid conveying of solid particles, pipe inclination resulted in considerably different transport phenomena relative to those observed for horizontal orientation. Key distinguishing features such as backward bed movement and enhanced particle suspension were observed and were found to be highly gas-liquid ratio dependent. Using image processing, the solid particle suspension layer was quantified as a function of the gas-liquid flow. The measurements presented provide fundamental insights into the influence of upward pipe inclination on bed-load mode solid transportation in a closed conduit.
Development of Boiling Type Cooling System Using Electrohydrodynamics Effect
Authors: Kano Ichiro , Higuchi Yuta , Chika Tadashi
Published: July 2013

This paper describes results from an experimental study of the effect of an electric field on nucleate boiling and the critical heat flux (CHF) in pool boiling at atmospheric pressure. A dielectric liquid of HFE-7100 (3 M Co.) was used as working fluid. A heating surface was polished with the surface roughness (Ra) of 0.05 μm. A microsized electrode, in which the slits were provided, was designed in order to generate non uniform high electric fields and to produce electrohydrodynamic (EHD) effects with the application of high voltages. The obtained results confirmed the enhancement of CHF since the EHD effects increased the CHF to 47 W/cm2 at the voltage of −1500 V, which was three times as much as CHF for the free convection boiling. From the observations of the behavior of bubbles over the electrode and of the boiling surface condition, the instability between the liquid and the vapor increased the heat flux, the heat transfer coefficient (HTC), and the CHF. The usual traveling wave on the bubble interface induced by the Kelvin-Helmholtz instability was modified by adding the EHD effects. The ratio of critical heat flux increase with and without the electric field was sufficiently predicted by the frequency ratio of liquid–vapor surface at the gap between the boiling surface and the electrode.
Condensation on Superhydrophobic Copper Oxide Nanostructures
Authors: Enright Ryan , Miljkovic Nenad , Dou Nicholas , Nam Youngsuk , Wang Evelyn N.
Published: July 2013

Condensation is an important process in both emerging and traditional power generation and water desalination technologies. Superhydrophobic nanostructures promise enhanced condensation heat transfer by reducing the characteristic size of departing droplets via coalescence-induced shedding. In this work, we investigated a scalable synthesis technique to produce functionalized oxide nanostructures on copper surfaces capable of sustaining superhydrophobic condensation and characterized the growth and departure behavior of the condensed droplets. Nanostructured copper oxide (CuO) films were formed via chemical oxidation in an alkaline solution resulting in dense arrays of sharp CuO nanostructures with characteristic heights and widths of ≈1 μm and ≈300 nm, respectively. To make the CuO surfaces superhydrophobic, they were functionalized by direct deposition of a fluorinated silane molecular film or by sputtering a thin gold film before depositing a fluorinated thiol molecular film. Condensation on these surfaces was characterized using optical microscopy and environmental scanning electron microscopy to quantify the distribution of nucleation sites and elucidate the growth behavior of individual droplets with characteristic radii of ≈1–10 μm at supersaturations ≤1.5. Comparison of the measured individual droplet growth behavior to our developed heat transfer model for condensation on superhydrophobic surfaces showed good agreement. Prediction of the overall heat transfer enhancement in comparison to a typical dropwise condensing surface having an identical nucleation density suggests a restricted regime of enhancement limited to droplet shedding radii <~2.5 μm due to the large apparent contact angles of condensed droplets on the fabricated CuO surfaces. The findings demonstrate that superhydrophobic condensation typified by coalescence-induced droplet shedding may not necessarily enhance heat transfer and highlights the need for further quantification of the effects of surface structure on nucleation density and careful surface design to minimize parasitic thermal resistances.
Conjugated Convection-Conduction Analysis in Microchannels With Axial Diffusion Effects and a Single Domain Formulation
Authors: Knupp Diego C. , Naveira-Cotta Carolina P. , Cotta Renato M.
Published: July 2013

An extension of a recently proposed single domain formulation of conjugated conduction–convection heat transfer problems is presented, taking into account the axial diffusion effects at both the walls and fluid regions, which are often of relevance in microchannels flows. The single domain formulation simultaneously models the heat transfer phenomena at both the fluid stream and the channel walls, by making use of coefficients represented as space variable functions, with abrupt transitions occurring at the fluid-wall interface. The generalized integral transform technique (GITT) is then employed in the hybrid numerical–analytical solution of the resulting convection–diffusion problem with variable coefficients. With axial diffusion included in the formulation, a nonclassical eigenvalue problem may be preferred in the solution procedure, which is itself handled with the GITT. To allow for critical comparisons against the results obtained by means of this alternative solution path, we have also proposed a more direct solution involving a pseudotransient term, but with the aid of a classical Sturm-Liouville eigenvalue problem. The fully converged results confirm the adequacy of this single domain approach in handling conjugated heat transfer problems in microchannels, when axial diffusion effects must be accounted for.
Dynamic Characterization of a Valveless Micropump Considering Entrapped Gas Bubbles
Authors: Li Songjing , Liu Jixiao , Jiang Dan
Published: July 2013

Unexpected gas bubbles in microfluidic devices always bring the problems of clogging, performance deterioration, and even device functional failure. For this reason, the aim of this paper is to study the characterization variation of a valveless micropump under different existence conditions of gas bubbles based on a theoretical modeling, numerical simulation, and experiment. In the theoretical model, we couple the vibration of piezoelectric diaphragm, the pressure drop of the nozzle/diffuser and the compressibility of working liquid when gas bubbles are entrapped. To validate the theoretical model, numerical simulation and experimental studies are carried out to investigate the variation of the pump chamber pressure influenced by the gas bubbles. Based on the numerical simulation and the experimental data, the outlet flow rates of the micropump with different size of trapped gas bubbles are calculated and compared, which suggests the influence of the gas bubbles on the dynamic characterization of the valveless micropump.
A Hybrid Partial Coherence and Geometry Optics Model of Radiative Property on Coated Rough Surfaces
Authors: Qiu Jun , Ting Wu Yuan , Huang Zhifeng , Hsu Pei-Feng , Liu Lin-Hua , Zhou Huai-Chun
Published: July 2013

Thermal and optical engineering applications of electromagnetic wave scattering from rough surfaces include temperature measurement, radiation heating process, etc. Most of the surfaces have random roughness and are often with coating material different from the substrate. However, the understanding of radiative properties of coated rough surfaces is not well addressed at this point. This paper presented a novel hybrid partial coherence and geometry optics (HPCGO) model to improve the generic geometry optics (GO) prediction by incorporating a previously developed partial coherence reflectance equation. In this way, HPCGO expands the applicable region of GO model and largely reduces the computation time of integrating different wavelength results in the regular hybrid model that considers coherence effect only. In this study, the HPCGO model is first compared with the more rigorous Maxwell equations solvers, the finite-difference time-domain (FDTD) method, and integral equation (IE) method. Then, the HPCGO model is applied to study the coherent effect of directional-hemispherical reflectance from coated rough surfaces. It is found the roughness of coated rough surface can cause partially coherent or noncoherent scattered light even if the incident light source is coherent. It also shows the reflected electromagnetic wave's coherence effect reduces with increased coating thickness and surface roughness, besides the previously recognized incident wave-number bandwidth. The effect of reduce coherence in scattered wave is quantified. Finally a regime map, even limited in the roughness and coating thickness dimensionless parameter ranges, provides the region of validity of the HPCGO model.
Electron Acceleration in the Heart of the Van Allen Radiation Belts
Authors: Reeves G. D. , Spence H. E. , Henderson M. G. , Morley S. K. , Friedel R. H. W. , Funsten H. O. , Baker D. N. , Kanekal S. G. , Blake J. B. , Fennell J. F. , Claudepierre S. G. , Thorne R. M. , Turner D. L. , Kletzing C. A. , Kurth W. S. , Larsen B. A. , Niehof J. T.
Published: July 2013

Local Acceleration

How the electrons trapped in Earth-encircling Van Allen radiation belts get accelerated has been debated since their discovery in 1958.

Reeves
et al.

(p.
991
, published online 25 July) used data from the Van Allen Radiation Belt Storm Probes, launched by NASA on 30 August 2012, to discover that radiation belt electrons are accelerated locally by wave-particle interactions, rather than by radial transport from regions of weaker to stronger magnetic fields.
Mapping of Functional Groups in Metal-Organic Frameworks
Authors: Kong Xueqian , Deng Hexiang , Yan Fangyong , Kim Jihan , Swisher Joseph A. , Smit Berend , Yaghi Omar M. , Reimer Jeffrey A.
Published: July 2013

Mapping Molecular Linkers

In metal-organic framework compounds, inorganic centers (metal atoms or clusters) are linked by bidentate organic groups. Normally, the same group is used throughout the structure, but recently, synthesis with linkers bearing different functional groups has produced well-defined materials.

Kong
et al.

(p.
882
, published online 25 July) combined solid-state nuclear magnetic resonance and molecular simulations to map the distributions of linkers in these materials as random, well-mixed, or clustered.
Polyploids Exhibit Higher Potassium Uptake and Salinity Tolerance in
Arabidopsis
Authors: Chao Dai-Yin , Dilkes Brian , Luo Hongbing , Douglas Alex , Yakubova Elena , Lahner Brett , Salt David E.
Published: July 2013

Double Is Not Trouble

The doubling of the genome to create polyploidy is common among land plants, and most major flowering plant lineages exhibit some history of genome duplication. However, the physiological advantages of a doubled genome are not well understood.

Chao
et al.

(p. 658, published online 25 July) identified accessions of the model plant
Arabidopsis thaliana
with naturally doubled genomes and found that the cytotype of the root, but not shoot, in these natural, as well as in artificially induced, polyploid plants appears to confer increased salt tolerance by regulating leaf potassium levels.
Application of Variable-Number Tandem-Repeat Typing To Discriminate Ralstonia solanacearum Strains Associated with English Watercourses and Disease Outbreaks
Authors: Parkinson Neil , Bryant Ruth , Bew Janice , Conyers Christine , Stones Robert , Alcock Michael , Elphinstone John
Published: July 2013

Variable-number tandem-repeat (VNTR) analysis was used for high-resolution discrimination among
Ralstonia solanacearum
phylotype IIB sequevar 1 (PIIB-1) isolates and further evaluated for use in source tracing. Five tandem-repeat-containing loci (comprising six tandem repeats) discriminated 17 different VNTR profiles among 75 isolates from potato, geranium, bittersweet (
Solanum dulcamara
), tomato, and the environment.
R. solanacearum
isolates from crops at three unrelated outbreak sites where river water had been used for irrigation had distinct VNTR profiles that were shared with PIIB-1 isolates from infected bittersweet growing upriver of each site. The VNTR profiling results supported the implication that the source of
R. solanacearum
at each outbreak was contaminated river water. Analysis of 51 isolates from bittersweet growing in river water at different locations provided a means to evaluate the technique for studying the epidemiology of the pathogen in the environment. Ten different VNTR profiles were identified among bittersweet PIIB-1 isolates from the River Thames. Repeated findings of contiguous river stretches that produced isolates that shared single VNTR profiles supported the hypothesis that the pathogen had disseminated from infected bittersweet plants located upriver. VNTR profiles shared between bittersweet isolates from two widely separated Thames tributaries (River Ray and River Colne) suggested they were independently contaminated with the same clonal type. Some bittersweet isolates had VNTR profiles that were shared with potato isolates collected outside the United Kingdom. It was concluded that VNTR profiling could contribute to further understanding of
R. solanacearum
epidemiology and assist in control of future disease outbreaks.
FLO11
Gene Is Involved in the Interaction of Flor Strains of Saccharomyces cerevisiae with a Biofilm-Promoting Synthetic Hexapeptide
Authors: Bou Zeidan Marc , Carmona Lourdes , Zara Severino , Marcos Jose F.
Published: July 2013

Saccharomyces cerevisiae
“flor” yeasts have the ability to form a buoyant biofilm at the air-liquid interface of wine. The formation of biofilm, also called velum, depends on
FLO11
gene length and expression.
FLO11
encodes a cell wall mucin-like glycoprotein with a highly O-glycosylated central domain and an N-terminal domain that mediates homotypic adhesion between cells. In the present study, we tested previously known antimicrobial peptides with different mechanisms of antimicrobial action for their effect on the viability and ability to form biofilm of
S. cerevisiae
flor strains. We found that PAF26, a synthetic tryptophan-rich cationic hexapeptide that belongs to the class of antimicrobial peptides with cell-penetrating properties, but not other antimicrobial peptides, enhanced biofilm formation without affecting cell viability in ethanol-rich medium. The PAF26 biofilm enhancement required a functional
FLO11
but was not accompanied by increased
FLO11
expression. Moreover, fluorescence microscopy and flow cytometry analyses showed that the PAF26 peptide binds flor yeast cells and that a
flo11
gene knockout mutant lost the ability to bind PAF26 but not P113, a different cell-penetrating antifungal peptide, demonstrating that the
FLO11
gene is selectively involved in the interaction of PAF26 with cells. Taken together, our data suggest that the cationic and hydrophobic PAF26 hexapeptide interacts with the hydrophobic and negatively charged cell wall, favoring Flo11p-mediated cell-to-cell adhesion and thus increasing biofilm biomass formation. The results are consistent with previous data that point to glycosylated mucin-like proteins at the fungal cell wall as potential interacting partners for antifungal peptides.
Draft Genome Sequences of Four Dickeya dianthicola and Four Dickeya solani Strains
Authors: Pritchard Leighton , Humphris Sonia , Baeyen Steve , Maes Martine , Van Vaerenbergh Johan , Elphinstone John , Saddler Gerry , Toth Ian
Published: July 2013

Dickeya dianthicola
and “
Dickeya solani
” are currently the dominant bacterial pathogens of potatoes in Europe. Here, we present the draft genome sequences of four strains of each pathogen.
Complete Genome Sequence of Salmonella enterica Serovar Typhimurium U288
Authors: Hooton Steven P. T. , Timms Andrew R. , Moreton Joanna , Wilson Ray , Connerton Ian F.
Published: July 2013

Salmonella enterica
serovar Typhimurium U288 has firmly established itself within the United Kingdom pig production industry. The prevalence of this highly pathogenic multidrug-resistant serovar at such a critical point in the food chain is therefore of great concern. To enhance our understanding of this microorganism, whole-genome and plasmid sequencing was performed.
Function of a Glutamine Synthetase-Like Protein in Bacterial Aniline Oxidation via γ-Glutamylanilide
Authors: Takeo Masahiro , Ohara Akira , Sakae Shinji , Okamoto Yasuhiro , Kitamura Chitoshi , Kato Dai-ichiro , Negoro Seiji
Published: July 2013

Acinetobacter
sp. strain YAA has five genes (
atdA1
to
atdA5
) involved in aniline oxidation as a part of the aniline degradation gene cluster. From sequence analysis, the five genes were expected to encode a glutamine synthetase (GS)-like protein (AtdA1), a glutamine amidotransferase-like protein (AtdA2), and an aromatic compound dioxygenase (AtdA3, AtdA4, and AtdA5) (M. Takeo, T. Fujii, and Y. Maeda, J. Ferment. Bioeng. 85:17-24, 1998). A recombinant
Pseudomonas
strain harboring these five genes quantitatively converted aniline into catechol, demonstrating that catechol is the major oxidation product from aniline. To elucidate the function of the GS-like protein AtdA1 in aniline oxidation, we purified it from recombinant
Escherichia coli
harboring
atdA1
. The purified AtdA1 protein produced gamma-glutamylanilide (γ-GA) quantitatively from aniline and
l
-glutamate in the presence of ATP and MgCl
2
. This reaction was identical to glutamine synthesis by GS, except for the use of aniline instead of ammonia as the substrate. Recombinant
Pseudomonas
strains harboring the dioxygenase genes (
atdA3
to
atdA5
) were unable to degrade aniline but converted γ-GA into catechol, indicating that γ-GA is an intermediate to catechol and a direct substrate for the dioxygenase. Unexpectedly, a recombinant
Pseudomonas
strain harboring only
atdA2
hydrolyzed γ-GA into aniline, reversing the γ-GA formation by AtdA1. Deletion of
atdA2
from
atdA1
to
atdA5
caused γ-GA accumulation from aniline in recombinant
Pseudomonas
cells and inhibited the growth of a recombinant
Acinetobacter
strain on aniline, suggesting that AtdA2 prevents γ-GA accumulation that is harmful to the host cell.
Unilateral single-rooted primary mandibular first molar
Authors: Chaudhari Purva , Mallikarjuna Rachappa , Swadas Milan , Dave Bhavna
Published: July 2013

A 4-year-old boy reported food lodgement and pain in the lower left back tooth region. On examination, a deeply carious tooth with food lodgement was seen. On oral examination, numbers of teeth were found to be carious and required restorations and endodontic treatments according to radiographic evaluation. Radiograph of mandibular left first deciduous molar revealed an unusual morphology of root. It was single-rooted and presented with Vertucci's class I canal. The tooth was treated by pulpectomy followed by a stainless steel crown. All other carious teeth were treated as planned.
Management of type 1 diabetes mellitus using in vitro autologous adipose tissue trans-differentiated insulin-making cells
Authors: Dave Shruti D , Trivedi Hargovind L , Chooramani Saroj G , Chandra Tulika
Published: July 2013

Type 1 diabetes mellitus (T1DM) is a result of autoimmune destruction of insulin-producing β cells of pancreas. Insulin is a widely used therapeutic modality. Nearing a complete century since the discovery of insulin, it is time to expect change in management strategies of T1DM. We report two men aged 22 and 15 years, respectively, with T1DM since 6 and 11 years, on exogenous insulin therapy of 64 and 56 International units (IU)/day respectively. We infused in vitro generated insulin-making cells trans-differentiated from donor adipose tissue derived mesenchymal stem cells and bone marrow-derived haematopoietic stem cells in their abdominal subcutaneous tissue, portal and thymic circulation under non-myeloablative conditioning. Over follow-up of 22.93 and 13.8 months they have stable blood sugar levels with glycosylated haemoglobin level of 6.3% and 6.8% with present insulin requirement of 18  and 22 IU/day, respectively.
Basidiobolomycosis a mysterious fungal infection mimic small intestinal and colonic tumour with renal insufficiency and ominous outcome
Authors: Taghipour Zahir Shokouh , Sharahjin Naser Sefidrokh , Kargar Saeed
Published: July 2013

Basidiobolomycosis is a rare fungal infection caused byBasidiobolus ranaruma worldwide environmental saprophyte fungus that is potentially a pathogen.B ranarummainly affects the subcutaneous tissues but gastrointestinal and disseminated infections rarely have been reported previously. We report a case ofB ranaruminfection in a 12-year-old immunocompetent boy presented with abdominal pain from 2 months earlier before admission in the hospital. Abdominal CT scan revealed a lobulated mass-like lesion in the vicinity of right lower quadrant enveloping ascending colon and terminal ileum with involvement of mesentery. Histopathological examination showed severe full-thickness infiltration of inflammatory cells mainly eosinophils admixed with multinucleated giant cells and large areas of necrosis with granulomatous feature. Periodic acid Schiff staining demonstrated thin-walled septate fungal hyphae's surrounded by eosinophilic material (Splendore-Hoppeli phenomenon) identified as a basidiobolomycosis.
Effects of centrally acting ACE inhibitors on the rate of cognitive decline in dementia
Authors: Gao Yang , O'Caoimh Rónán , Healy Liam , Kerins David M , Eustace Joseph , Guyatt Gordon , Sammon David , Molloy D William
Published: July 2013

Objectives

There is growing evidence that antihypertensive agents, particularly centrally acting ACE inhibitors (CACE-Is), which cross the blood–brain barrier, are associated with a reduced rate of cognitive decline. Given this, we compared the rates of cognitive decline in clinic patients with dementia receiving CACE-Is (CACE-I) with those not currently treated with CACE-Is (NoCACE-I), and with those who started CACE-Is, during their first 6 months of treatment (NewCACE-I).

Design

Observational case–control study.

Setting

2 university hospital memory clinics.

Participants

817 patients diagnosed with Alzheimer's disease, vascular or mixed dementia. Of these, 361 with valid cognitive scores were included for analysis, 85 CACE-I and 276 NoCACE-I.

Measurements

Patients were included if the baseline and end-point (standardised at 6 months apart) Standardised Mini-Mental State Examination (SMMSE) or Quick Mild Cognitive Impairment (Qmci) scores were available. Patients with comorbid depression or other dementia subtypes were excluded. The average 6-month rates of change in scores were compared between CACE-I, NoCACE-I and NewCACE-I patients.

Results

When the rate of decline was compared between groups, there was a significant difference in the median, 6-month rate of decline in Qmci scores between CACE-I (1.8 points) and NoCACE-I (2.1 points) patients (p=0.049), with similar, non-significant changes in SMMSE. Median SMMSE scores improved by 1.2 points in the first 6 months of CACE treatment (NewCACE-I), compared to a 0.8 point decline for the CACE-I (p=0.003) group and a 1 point decline for the NoCACE-I (p=0.001) group over the same period. Multivariate analysis, controlling for baseline characteristics, showed significant differences in the rates of decline, in SMMSE, between the three groups, p=0.002.

Conclusions

Cognitive scores may improve in the first 6 months after CACE-I treatment and use of CACE-Is is associated with a reduced rate of cognitive decline in patients with dementia.
The patient is in: patient involvement strategies for diagnostic error mitigation
Authors: McDonald Kathryn M , Bryce Cindy L , Graber Mark L
Published: July 2013

Although healthcare quality and patient safety have longstanding international attention, the target of reducing diagnostic errors has only recently gained prominence, even though numerous patients, families and professional caregivers have suffered from diagnostic mishaps for a long time. Similarly, patients have always been involved in their own care to some extent, but only recently have patients sought more opportunities for engagement and participation in healthcare improvements. This paper brings these two promising trends together, analysing strategies for patient involvement in reducing diagnostic errors in an individual's own care, in improving the healthcare delivery system's diagnostic safety, and in contributing to research and policy development on diagnosis-related issues.
The diagnostic accuracy of pleural effusion and plasma samples versus tumour tissue for detection of EGFR mutation in patients with advanced non-small cell lung cancer: comparison of methodologies
Authors: Liu Xiaoqing , Lu Yachao , Zhu Guanshan , Lei Yao , Zheng Li , Qin Haifeng , Tang Chuanhao , Ellison Gillian , McCormack Rose , Ji Qunsheng
Published: July 2013

Aims

To evaluate the suitability of malignant pleural effusion (MPE) and plasma as surrogate samples for epidermal growth factor receptor (EGFR) mutation detection, and compare three different detection methods.

Methods

Matched tissue and plasma samples were collected from patients with advanced non-small cell lung cancer (NSCLC) (stage IIIB/IV adenocarcinoma/adenosquamous carcinoma), with matched MPE samples collected from a subgroup. DNA was extracted from tissue, MPE cell block, MPE supernatant and plasma before mutation detection by amplification refractory mutation system (ARMS) (all samples), Sanger sequencing and mutant-specific immunohistochemistry (IHC) (tissue and MPE cell blocks only).

Results

Sensitivity of MPE cell block, MPE supernatant and plasma versus tissue: 81.8% (9/11), 63.6% (7/11) and 67.5% (27/40); specificity was 80.0% (8/10), 100% (10/10) and 100% (46/46), respectively. Sensitivity of Sanger sequencing versus ARMS: 81.8% (27/33) for tissue, 40% (4/10) for MPE cell blocks; specificity was 100% (36/36 and 12/12) for both. Sensitivity of mutant-specific IHC versus ARMS: 54.8% (17/31) for tissue, 50.0% (6/12) for MPE cell blocks; specificity was 97.1% (34/35) and 100% (14/14), respectively.

Conclusions

MPE and plasma are valid surrogates for NSCLC tumour EGFR mutation detection when tissue is not available. ARMS is most suitable for mutation detection in tissue and MPE cell blocks; however, mutant-specific IHC could be a complementary method when DNA-based molecular testing is unavailable.
Pattern and cause of fractures in patients who abuse alcohol: what should we do about it?
Authors: Kelly Kieran Nial , Kelly Clive
Published: July 2013

Alcohol abuse is increasing in the UK and contributes significantly to the rising number of acute hospital admissions. The effects are increasingly seen among younger people who binge drink. The effects of excess alcohol on the skeleton have attracted far less attention than those on other organs, but the risk of fractures at important sites, such as the hips and vertebrae, is greatly increased in alcoholics. This is partly owing to reductions in bone mineral density, but other factors such as an increased rate of falls play an important part. The contribution of excess alcohol consumption to the risk of fractures is recognised in the widely available fracture assessment tool (FRAX). The mechanisms of fracture in alcohol abusers are complex and involve direct effects on bone cells, and indirect effects, mediated by alcohol, on the endocrine system, pancreas and cytokine system. Poor nutrition, with a reduction in body mass index and vitamin D levels, often contributes significantly. Prevention and treatment of fractures in alcohol abusers has received limited attention, and there are surprisingly few therapeutic trials to guide clinical intervention. Abstinence has been shown to improve markers of bone turnover within 2 months. However, compliance with oral therapeutic agents is often poor, and bisphosphonates may be contraindicated in patients with alcoholic liver disease and varices. The emergence of newer therapeutic options may facilitate controlled prospective studies of the role of parenteral agents in providing protection against both primary and secondary osteoporotic fractures among patients with alcohol abuse.