bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and Experiment of a Flexible Module Actuated by Shape Memory Alloy Wire
Authors: Hadi A. , Qasemi M. , Elahinia M. , Moghaddam N. S.
Published: December 2014

In recent years many investigations have been performed on design and fabrication of micro mechanical manipulators. One of the practical usages of this manipulator is endoscopy. In an endoscopy system, a small manipulator with high maneuverability and flexibility is required to support the probe’s movement into a colon easier than classic manipulators. In this paper a basic flexible module is presented for use in such an application. The structure of presented module is simple and includes a compressive spring which could be bent to the sides. This tends to more simplicity in addition to proper flexibility. Connecting three wires of shape memory alloy (SMA) uniformly distributed in circumference of spring with an angle of 120 degrees, it is possible to provide an almost large displacement and orientation change between the end planes of module. By using three wires and stimulating them individually or together, different rotation regimes are provided. The flexible module deformation is modeled in this paper thoroughly. Deflection and orientation of spring as the basic structure of the module is studied under the loads. Also, Brinson model is used for modeling the shape memory alloy wire. Afterward, the spring model is coupled with SMA model to describe the dynamic behavior of module under a defined activation. The simulation is implemented in MATLAB-Simulink Though the developed simulation platform, the trajectory of module may be extracted and used for developing a modular manipulator. An experimental setup is prepared to verify the simulation results. Through the simulations, module performance in addition to proper geometrical parameters for the considered application is calculated through the simulations. It is shown that a proper relation between geometrical parameters of spring (like outer diameter, spring wire diameter and number of coils) in combination with a suitable SMA wire in diameter, affect the maximum deformation of SMA-actuated module.
Experimental and Theoretical Investigation of the Giant MR-Effect
Authors: Hegger Christian , Maas Jürgen
Published: December 2014

This contribution deals with the theoretical and experimental investigation of the giant MR-effect. The giant MR-effect can be utilized to increase the yield stress of magnetorheological fluids (MRF). To obtain a boost of the yield stress the MRF has to be normally compressed while it is exposed to a magnetic field in order to create stronger particle structures. For the experimental investigation a MRF test actuator with an conical shear gap is designed, enabling an adjustment of the shear gap’s height by applying a compressing normal force. The experimental investigation points out that a potentially increase of the yield stress can be achieved on the one hand. On the other hand it is dependent on the magnetic field strength during the compression as well as on the shear rate and shear strain. The results are used to motivate a modeling approach which combines the rheological behavior with tribological effects. The validation of the modeling approach shows a good accordance to the behavior of the physical investigated giant MR-effect.
Smart Structure Integration Through Ultrasonic Additive Manufacturing
Authors: Dapino Marcelo J.
Published: December 2014

Ultrasonic additive manufacturing (UAM), a form of 3D printing based on ultrasonic metal welding, allows for room-temperature fabrication of adaptive structures with seamlessly embedded sensors and actuators. UAM combines solid-state welding of metallic foils, automated additive foil layering, and CNC machining. The most recent UAM systems utilize 9 kW of ultrasonic power for improved build strength and quality over low power systems, leading to previously unfeasible smart structures. Current UAM efforts in this area are focused on embedding smart materials, fiber optics, and cooling channels into metallic matrices. Since UAM process temperatures do not exceed one half of the melting temperature of the matrix, various alloys such as NiTi and FeGa, and polymers such as PVDF, have been successfully embedded without degradation of the smart material or the matrix. This paper aims to demonstrate the benefits of UAM, with particular emphasis on smart components for vehicle design. Example concepts include stiffness-tunable structures, thermally invariant composites, and materials with embedded cooling channels.
Power Savings of a Variable Recruitment Hydraulic Artificial Muscle Actuation Scheme
Authors: Meller Michael , Garcia Ephrahim
Published: December 2014

We investigate utilizing inelastic bladder hydraulic artificial muscle actuators as muscle fibers. These muscle fibers are then grouped together to form a variable recruitment artificial muscle bundle. This muscle bundle configuration is biologically inspired, where in skeletal muscle, different numbers of motor units are recruited to match the load by increasing the number of motor neurons firing. This results in extremely efficient locomotion in nature. It is desired to use a similar methodology to increase the actuation efficiency of valve-controlled hydraulic systems. Such hydraulic control systems induce a pressure drop in the valves to throttle the flow to the cylinder actuators. Using the valves in this manner is simple but very inefficient. Hence, this paper presents selectively recruiting different numbers of the hydraulic artificial muscle fibers to match a required loading scenario similar to our bipedal robot. By using fewer of the muscle fibers to match a smaller load, less power is consumed from the hydraulic power unit because instead of inducing a pressure drop, the volume of fluid delivered is decreased. The potential efficiency improvements associated with this actuation scheme is compared to a traditional hydraulic system with differential cylinders.
Phase Control of a Bio-Inspired Meta-Structural Locomotion Robot
Authors: Fang Hongbin , Wang Chenghao , Li Suyi , Wang K. W. , Xu Jian
Published: December 2014

This research investigates the rectilinear locomotion of a meta-structural robot inspired by the earthworm. First of all, an equivalent multi-segment model of the meta-structural locomotion robot is derived. By the method of averaging, the robot’s average steady-state velocity is obtained, which is a function of the phase differences among segments. Then a novel locomotion control scheme of adjusting actuation phases is proposed for the robot. It is shown that such control of the phase differences among actuators can significantly tailor not only the magnitude but also the direction of the robot’s average steady-state velocity. Locomotion tests with equal phase difference among segments are carried out on the robot prototype in a horizontal pipe. The predicted phase-velocity relationship is verified, and it is shown that the proposed control is more effective than the more traditional peristaltic locomotion gaits. The presented earthworm-like robot belongs to the general class of metastructures, the concept of synthesizing adaptive structures via modular element design and integration. This study lays the foundation for understanding and advancing the properties of such meta-structural locomotion robots.
The Adaptive Aspect Ratio Morphing Wing: Design Concept and Low Fidelity Skin Optimization
Authors: Woods Benjamin King Sutton , Friswell Michael I.
Published: December 2014

This work introduces a new span morphing concept under development at Swansea University. Known as the Adaptive Aspect Ratio wing, this concept couples a compliant skin material to a mechanism based internal structure to create a morphing wing capable of significant changes in span and aspect ratio. The four key technologies of the concept, namely the elastomeric matric composite skin, the telescoping spar, the sliding ribs and the strap drive, are first introduced and discussed. The compliant skin is established to be the dominant component in the overall design of this concept, requiring careful balancing between in-plane actuation force requirements and out-of-plane stiffness under aerodynamic loading. An initial skin design optimization exercise is then carried out using analytical models of the skin’s behaviour, providing significant insight into the interplay between the various parameters of the skin design.
Measurement of the Second Order Elastic Constants of Langasite Crystals
Authors: Kosinski John A. , Zhang Haifeng , Bao Yuanye
Published: December 2014

Langasite (LGS) has attracted considerable attention from researchers as a potential substrate material for piezoelectric device applications due to its very good frequency stability and moderately large electromechanical coupling factors for acoustic wave devices. This paper presents a new determination of the second order elastic constants of LGS using acoustic wave velocities measured by a time-of-flight cross-correlation method. Two types of ultrasonic transducers have been used to generate longitudinal and shear bulk waves that propagate through cube-shaped specimens. The specimens and attached transducers are placed inside a temperature chamber to maintain a constant environmental temperature during the measurements. We present a full comparison between the new values determined here and those previously reported.
Morphing Aircraft: An Improbable Dream?
Authors: Friswell Michael I.
Published: December 2014

Compliant aircraft, with a range of deformations comparable to birds, has been a dream for many years. Earlier aviation pioneers tried to replicate aspects of bird flight, but higher air speeds and larger payloads have required aircraft design to deviate from their biological inspiration. The design of conventional fixed wing aircraft can only be optimized for a limited region of the flight envelope; mechanisms such as deployable flaps and wing sweep are used extensively to enlarge this envelope. The development of more accurate analysis tools, advanced smart materials, and the increasingly demands for improved aircraft performance, are driving research into compliant morphing aircraft. These aircraft have the potential to adapt and optimize their shape to improve flight performance or achieve multi-objective mission roles. However this technology has rarely been adopted on production aircraft. This paper will critically review the progress made to date on compliant morphing aircraft research, and summarize the challenges that need to be addressed before such technology can be adopted widely. In particular the need to demonstrate system level performance benefits for morphing technology is emphasized.
Atomic layer deposition of epitaxial layers of anatase on strontium titanate single crystals: Morphological and photoelectrochemical characterization
Authors: Kraus Theodore J. , Nepomnyashchii Alexander B. , Parkinson B. A.
Published: December 2014

Atomic layer deposition was used to grow epitaxial layers of anatase (001) TiO2 on the surface of SrTiO3 (100) crystals with a 3% lattice mismatch. The epilayers grow as anatase (001) as confirmed by x-ray diffraction. Atomic force microscope images of deposited films showed epitaxial layer-by-layer growth up to about 10 nm, whereas thicker films, of up to 32 nm, revealed the formation of 2–5 nm anatase nanocrystallites oriented in the (001) direction. The anatase epilayers were used as substrates for dye sensitization. The as received strontium titanate crystal was not sensitized with a ruthenium-based dye (N3) or a thiacyanine dye (G15); however, photocurrent from excited state electron injection from these dyes was observed when adsorbed on the anatase epilayers. These results show that highly ordered anatase surfaces can be grown on an easily obtained substrate crystal.
Functional heterogeneity of human memory CD4
+
T cell clones primed by pathogens or vaccines
Authors: Becattini Simone , Latorre Daniela , Mele Federico , Foglierini Mathilde , De Gregorio Corinne , Cassotta Antonino , Fernandez Blanca , Kelderman Sander , Schumacher Ton N. , Corti Davide , Lanzavecchia Antonio , Sallusto Federica
Published: December 2014

For T cells, variety is the spice of life

CD4
+
helper T cells come in a variety of flavors. This allows them to respond in a manner that is tailored to the pathogen they encounter. Becattini
et al.
wondered whether multiple “flavors” of human CD4
+
T cells respond to specific stimuli or if just one flavor dominates. To find out, they stimulated human memory CD4
+
T cells with a fungus, a bacteria, or a vaccine antigen. Multiple helper cell subsets participated in each response. T cell receptor sequencing revealed that in some cases, T cells with the same specificity acquired different helper cell fates. Thus, there is more heterogeneity in human T cell responses than previously appreciated.

Science
, this issue p.
400
Taxonomic Affiliation of New Genomes Should Be Verified Using Average Nucleotide Identity and Multilocus Phylogenetic Analysis
Authors: Figueras María José , Beaz-Hidalgo Roxana , Hossain Mohammad J. , Liles Mark R.
Published: December 2014

The average nucleotide identity (ANI) determines if two genomes belong to the same species. Using ANI, we detected mislabeled genomes and recommend verifying with ANI and multilocus phylogenetic analysis the species affiliations of the announced genomes. The slightly different results obtained with different ANI calculation software can potentially mislead taxonomic inferences.
A Novel Itera-Like Densovirus Isolated by Viral Metagenomics from the Sea Barley
Hordeum marinum
Authors: François S. , Bernardo P. , Filloux D. , Roumagnac P. , Yaverkovski N. , Froissart R. , Ogliastro M.
Published: December 2014

Densoviruses (DVs) infect arthropods and belong to the
Parvoviridae
family. Here, we report the complete coding sequence of a novel DV isolated from the plant
Hordeum marinum
(
Poaceae
) by viral metagenomics, and we confirmed reamplification by PCR. Phylogenetic analyses showed that this novel DV is related to the genus
Iteradensovirus
.
Draft Genome Sequence of Marine Flavobacterium Jejuia pallidilutea Strain 11shimoA1 and Pigmentation Mutants
Authors: Takatani Naoki , Nakanishi Masato , Meirelles Pedro , Mino Sayaka , Suda Wataru , Oshima Kenshiro , Hattori Masahira , Ohkuma Moriya , Hosokawa Masashi , Miyashita Kazuo , Thompson Fabiano L. , Niwa Ako , Sawabe Toko , Sawabe Tomoo
Published: December 2014

Here, we present the draft genome sequence of a novel carotenoid 2′-isopentenylsaproxanthin producer,
Jejuia pallidilutea
strain 11shimoA1, isolated from the surface of seaweed in Japan, and the ethyl methanesulfonate-induced pigmentation mutants. This genomic information will help to not only elucidate the 2′-isopentenylsaproxanthin biosynthetic pathway but also understand the evolution of flavobacteria.
Draft Genome Sequence of a Metabolically Diverse Antarctic Supraglacial Stream Organism,
Polaromonas
sp. Strain CG9_12, Determined Using Pacific Biosciences Single-Molecule Real-Time Sequencing Technology
Authors: Smith Heidi J. , Foreman Christine M. , Ramaraj Thiruvarangan
Published: December 2014

Polaromonas
species are found in a diversity of environments and are particularly common in icy ecosystems.
Polaromonas
sp. strain CG9_12 is an aerobic, Gram-negative, catalase-positive, white-pigmented bacterium of the
Proteobacteria
phylum. Here, we present the draft genome sequence of
Polaromonas
sp. strain CG9_12, isolated from an Antarctic supraglacial stream.
Complete Genome Sequence of Listeria monocytogenes Lm60, a Strain with an Enhanced Cold Adaptation Capacity
Authors: Tasara Taurai , Weinmaier Thomas , Klumpp Jochen , Rattei Thomas , Stephan Roger
Published: December 2014

The complete genome sequence of
Listeria monocytogenes
Lm60, a fast cold-adapting serotype 1/2a human isolate, is presented.
Draft Genome Sequence of the Nicotinate-Metabolizing Soil Bacterium Bacillus niacini DSM 2923
Authors: Harvey Zachary H. , Snider Mark J.
Published: December 2014

Bacillus niacini
is a member of a small yet diverse group of bacteria able to catabolize nicotinic acid. We report here the availability of a draft genome for
B. niacini
, which we will use to understand the evolution of its namesake phenotype, which appears to be unique among the species in its phylogenetic neighborhood.
Draft Genome Sequence of
Sphingopyxis
sp. Strain MWB1, a Crude-Oil-Degrading Marine Bacterium
Authors: Kim Jonghyun , Kim Soo Jung , Kim Seon Hee , Kim Seung Il , Moon Yoon-Jung , Park Sung-Joon , Kahng Hyung-Yeel , Chung Young-Ho
Published: December 2014

Sphingopyxis
sp. strain MWB1, which is capable of degrading crude oil, diesel, and kerosene, was isolated from crude oil–contaminated seashore in Tae-an, South Korea. Here, we report the draft genome sequence of this strain, which comprises 3,118,428 bp with a G+C content of 62.85 mol%.
Draft Genome Sequence of C:P1.5-1,10-8:F3-6:ST-11 Meningococcal Clinical Isolate Associated with a Cluster on a Cruise Ship
Authors: Neri A. , Fazio C. , Ciammaruconi A. , Anselmo A. , Fortunato A. , Palozzi A. , Vacca P. , Fillo S. , Lista F. , Stefanelli P.
Published: December 2014

Meningococcal serogroup C strains, in particular those belonging to the ST-11 clonal complex, are known to cause invasive diseases worldwide. We report the genome sequence of a
Neisseria meningitidis
strain linked to a cluster of cases of invasive meningococcal disease on a cruise ship that was described in 2012.
Potential economic impacts from improving breastfeeding rates in the UK
Authors: Pokhrel S , Quigley M A , Fox-Rushby J , McCormick F , Williams A , Trueman P , Dodds R , Renfrew M J
Published: December 2014

Rationale

Studies suggest that increased breastfeeding rates can provide substantial financial savings, but the scale of such savings in the UK is not known.

Objective

To calculate potential cost savings attributable to increases in breastfeeding rates from the National Health Service perspective.

Design and settings

Cost savings focussed on where evidence of health benefit is strongest: reductions in gastrointestinal and lower respiratory tract infections, acute otitis media in infants, necrotising enterocolitis in preterm babies and breast cancer (BC) in women. Savings were estimated using a seven-step framework in which an incidence-based disease model determined the number of cases that could have been avoided if breastfeeding rates were increased. Point estimates of cost savings were subject to a deterministic sensitivity analysis.

Results

Treating the four acute diseases in children costs the UK at least £89 million annually. The 2009–2010 value of lifetime costs of treating maternal BC is estimated at £959 million. Supporting mothers who are exclusively breast feeding at 1 week to continue breast feeding until 4 months can be expected to reduce the incidence of three childhood infectious diseases and save at least £11 million annually. Doubling the proportion of mothers currently breast feeding for 7–18 months in their lifetime is likely to reduce the incidence of maternal BC and save at least £31 million at 2009–2010 value.

Conclusions

The economic impact of low breastfeeding rates is substantial. Investing in services that support women who want to breast feed for longer is potentially cost saving.
Coronary artery dissection by an oversized balloon
Authors: Yafi Wael , Jacquemin Laurent
Published: December 2014

Percutaneous coronary intervention (PCI) as a treatment of coronary artery disease can be a simple, rapid procedure with a clear benefit for the patient, but it could also become a complex procedure with fatal consequences. These complications depend on the lesion itself, material used and also on operating staff. In this case we report a coronary artery dissection of the circumflex (CX) artery caused by inflation of an oversized balloon. We discuss here the management and evolution of this complication.
Role of oral doxycycline and large diameter bandage contact lens in the management of early post-trabeculectomy bleb leak
Authors: Kiranmaye Turaga , Garudadri Chandrasekhar S , Senthil Sirisha
Published: December 2014

A 27-year-old man with juvenile open angle glaucoma and medically uncontrolled intraocular pressure (IOP) underwent a trabeculectomy with mitomycin C in his right eye. One week postoperatively, he developed ischaemic necrosis of the conjunctiva with a bleb leak. This was managed conservatively with oral doxycycline 100 mg twice daily along with a topical low-dose steroid, antibiotic and cycloplegic and a large diameter bandage contact lens (BCL). There was dramatic improvement in the bleb appearance, the necrosis healed and the leak resolved. The patient had well-controlled IOP with a diffuse healthy bleb at 4 weeks, which was maintained at 2 years. This case illustrates the utility and importance of oral doxycycline in the management of early post-trabeculectomy conjunctival necrosis and the use of BCL in the management of a bleb leak. This safe and non-invasive method not only hastened the recovery but also helped in maintaining good bleb function.
Extended insulin boluses cannot control postprandial glycemia as well as a standard bolus in children and adults using insulin pump therapy
Authors: Lopez Prudence , Smart Carmel , Morbey Claire , McElduff Patrick , Paterson Megan , King Bruce R
Published: December 2014

Introduction

Insulin pumps are able to deliver bolus insulin as a standard, extended or combination bolus. There is minimal research to determine which bolus is preferable in different settings. Anecdotally, many patients utilizes only the standard bolus (SB) due to uncertainty regarding when and how to program the different bolus types. We compared postprandial glycemia when five different extended boluses (EBs) and an SB were used following a test meal. We sought to determine the impact of varying rates of insulin delivery from an EB on early postprandial glycemia.

Methods

We conducted a randomized, repeated measures trial of 20 children and adults comparing postprandial glycemic excursions following EBs given at five different rates with SB as a control. All EBs were delivered over 2 h. Rates of EBs were chosen to reflect EBs used in clinical practice: EB1HR=100% of insulin:carbohydrate ratio (ICR) per hour (200% ICR total dose); EB2HR=50% of ICR per hour; EB3HR=33% of ICR per hour; EB4HR=25% of ICR per hour; EB6HR=16% ICR per hour. A standardized breakfast was given and activity was standardized. Continuous glucose monitoring was used to assess glycemia for 2 h after the meal.

Results

The mean postprandial glycemic excursions were lower at 30, 60, and 90 min (p<0.05) for SB compared with all EBs. The mean peak postprandial glycemic excursion and the area under the curve was lower for SB compared with all EBs (p<0.05).

Discussion

EBs resulted in higher postprandial glycemic excursions than SB for 2 h after the meal. For a moderate glycemic index meal EBs are unable to control glycemia for 2 h after a meal as well as SB. Further studies with different meal types are required to determine the impact of differential delivery of the EB on postprandial glycemia.

Trial registration number

ACTRN12612000609853.
Synovial plicae of the knee joint: the role of advanced MRI
Authors: Vassiou Katerina , Vlychou Marianna , Zibis Aristidis , Nikolopoulou Athina , Fezoulidis Ioannis , Arvanitis Dimitrios
Published: December 2014

Synovial plicae are normal anatomical structures of the knee that may become symptomatic. MRI is an established technique for evaluating the anatomy of the knee, and it is a valuable tool for detecting plicae because of its high resolution resulting in increased tissue characterisation. At MRI, knee plicae appear as low-signal-intensity structures of variable size and thickness, and they are better visualised at fluid-sensitive sequences with or without fat suppression. The combined use of clinical examination and MRI may also facilitate the diagnosis of fibrotic or inflamed plicae that may be symptomatic. Arthroscopy remains the gold standard for recognition and repair of knee plicae in cases of knee dysfunction.
Landform signature of the Laurentide and Cordilleran ice sheets across Alberta during the last glaciation
Authors: Atkinson Nigel , Utting Daniel J. , Pawley Steven M.
Published: December 2014

Government geological survey maps and research publications have portrayed the distribution of glacial landforms associated with the advance and retreat of the Laurentide and Cordilleran ice sheets across Alberta at a local, regional, and continental scale. To date, this information has not been systematically synthesized into a single compilation at a consistent scale. Although this original work provided valuable information to constrain reconstructions of former ice sheet extent, configuration, and flow geometry, its derivation primarily from the interpretation of aerial photographs and the Shuttle Radar Topography Mission 90 m digital elevation model (DEM) may result in methodological inconsistencies and spatial biases. These biases, together with challenges associated with geomorphic mapping in densely forested areas of western and northern Alberta limit the usefulness of previous mapping when applied to inversion-based ice sheet reconstructions, which have specific input data demands. Recently, light detection and ranging (LiDAR) DEMs have become increasingly available throughout Alberta. Hill-shaded imagery of these data provides unprecedented geomorphic detail beneath the forest cover and reveals that that the glacial geomorphology of northern and western Alberta is more complex than previously recognized. In this paper, we describe the methodology and geomorphic criteria used to produce a glacial landform map of Alberta using previously published data, supplemented by comprehensive new analysis of high-resolution (2–25 m) DEMs. These include 306 624 km2of LiDAR imagery, with which it is now possible to verify and where necessary augment previous mapping, particularly across areas with a dense forest cover.
The discovery of the gluon
Authors: Ellis John
Published: December 2014

Soon after the postulation of quarks, it was suggested that they interact via gluons, but direct experimental evidence was lacking for over a decade. In 1976, Mary Gaillard, Graham Ross and the author suggested searching for the gluon via 3-jet events due to gluon bremsstrahlung in e+ e- collisions. Following our suggestion, the gluon was discovered at DESY in 1979 by TASSO and the other experiments at the PETRA collider.
Lattices in Social Networks with Influence
Authors: Grabisch Michel , Rusinowska Agnieszka
Published: December 2014

We present an application of lattice theory to the framework of influence in social networks. The contribution of the paper is not to derive new results, but to synthesize our existing results on lattices and influence. We consider a two-action model of influence in a social network in which agents have to make their yes–no decision on a certain issue. Every agent is preliminarily inclined to say either "yes" or "no", but due to influence by others, the agent's decision may be different from his original inclination. We discuss the relation between two central concepts of this model: Influence function and follower function. The structure of the set of all influence functions that lead to a given follower function appears to be a distributive lattice. We also consider a dynamic model of influence based on aggregation functions and present a general analysis of convergence in the model. Possible terminal classes to which the process of influence may converge are terminal states (the consensus states and nontrivial states), cyclic terminal classes and unions of Boolean lattices.
Reduction of Local Stress Concentration on Nanosheet in Layered Nanoparticles with Water Molecules
Authors: Sato Kiminori , Numata Kazuomi , Fujimoto Koichiro
Published: December 2014

The local stress concentration on 2D nanosheets is investigated for saponite layered nanoparticles by means of X-ray diffraction (XRD) and positronium (Ps) annihilation spectroscopy. XRD experiments indicated that the layered structure for the mechanochemically milled sample is maintained in the presence of H 2 O molecules. Ps annihilation studies of self-assembly revealed that the 2D nanosheets are well in-plane ordered after uniaxial pressure compaction without H 2 O molecules due to the efficient propagation of stress concentration. The present results of both XRD and Ps lifetime spectroscopy clearly demonstrates that the stress concentration on the 2D nanosheets can be reduced in the presence of H 2 O molecules.
Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies
Authors: Agar Susan M. , Geiger Sebastian
Published: December 2014

The introduction reviews topics relevant to the fundamental controls on fluid flow in carbonate reservoirs and to the prediction of reservoir performance. The review provides research and industry contexts for papers in this volume only. A discussion of global context and frameworks emphasizes the value yet to be captured from compare and contrast studies. Multidisciplinary efforts highlight the importance of greater integration of sedimentology, diagenesis and structural geology. Developments in analytical and experimental methods, stimulated by advances in the materials sciences, support new insights into fundamental (pore-scale) processes in carbonate rocks. Subsurface imaging methods relevant to the delineation of heterogeneities in carbonates highlight techniques that serve to decrease the gap between seismically resolvable features and well-scale measurements. Methods to fuse geological information across scales are advancing through multiscale integration and proxies. A surge in computational power over the last two decades has been accompanied by developments in computational methods and algorithms. Developments related to visualization and data interaction support stronger geoscience–engineering collaborations. High-resolution and real-time monitoring of the subsurface are driving novel sensing capabilities and growing interest in data mining and analytics. Together, these offer an exciting opportunity to learn more about the fundamental fluid-flow processes in carbonate reservoirs at the interwell scale.
Segmental transport of Ca2+and Mg2+along the gastrointestinal tract
Authors: Lameris Anke L. , Nevalainen Pasi I. , Reijnen Daphne , Simons Ellen , Eygensteyn Jelle , Monnens Leo , Bindels René J. M. , Hoenderop Joost G. J.
Published: December 2014

Calcium (Ca2+) and magnesium (Mg2+) ions are involved in many vital physiological functions. Since dietary intake is the only source of minerals for the body, intestinal absorption is essential for normal homeostatic levels. The aim of this study was to characterize the absorption of Ca2+as well as Mg2+along the gastrointestinal tract at a molecular and functional level. In both humans and mice the Ca2+channel transient receptor potential vanilloid subtype 6 (TRPV6) is expressed in the proximal intestinal segments, whereas Mg2+channel transient receptor potential melastatin subtype 6 (TRPM6) is expressed in the distal parts of the intestine. A method was established to measure the rate of Mg2+absorption from the intestine in a time-dependent manner by use of25Mg2+. In addition, local absorption of Ca2+and Mg2+in different segments of the intestine of mice was determined by using surgically implanted intestinal cannulas. By these methods, it was demonstrated that intestinal absorption of Mg2+is regulated by dietary needs in a vitamin D-independent manner. Also, it was shown that at low luminal concentrations, favoring transcellular absorption, Ca2+transport mainly takes place in the proximal segments of the intestine, whereas Mg2+absorption predominantly occurs in the distal part of the gastrointestinal tract. Vitamin D treatment of mice increased serum Mg2+levels and 24-h urinary Mg2+excretion, but not intestinal absorption of25Mg2+. Segmental cannulation of the intestine and time-dependent absorption studies using25Mg2+provide new ways to study intestinal Mg2+absorption.
Temporal and gefitinib-sensitive regulation of cardiac cytokine expression via chronic β-adrenergic receptor stimulation
Authors: Grisanti Laurel A. , Repas Ashley A. , Talarico Jennifer A. , Gold Jessica I. , Carter Rhonda L. , Koch Walter J. , Tilley Douglas G.
Published: December 2014

Chronic stimulation of β-adrenergic receptors (βAR) can promote survival signaling via transactivation of epidermal growth factor receptor (EGFR) but ultimately alters cardiac structure and contractility over time, in part via enhanced cytokine signaling. We hypothesized that chronic catecholamine signaling will have a temporal impact on cardiac transcript expression in vivo, in particular cytokines, and that EGFR transactivation plays a role in this process. C57BL/6 mice underwent infusion with vehicle or isoproterenol (Iso) ± gefitinib (Gef) for 1 or 2 wk. Cardiac contractility decreased following 2 wk of Iso treatment, while cardiac hypertrophy, fibrosis, and apoptosis were enhanced at both timepoints. Inclusion of Gef preserved contractility, blocked Iso-induced apoptosis, and prevented hypertrophy at the 2-wk timepoint, but caused fibrosis on its own. RNAseq analysis revealed hundreds of cardiac transcripts altered by Iso at each timepoint with subsequent RT-quantitative PCR validation confirming distinct temporal patterns of transcript regulation, including those involved in cardiac remodeling and survival signaling, as well as numerous cytokines. Although Gef infusion alone did not significantly alter cytokine expression, it abrogated the Iso-mediated changes in a majority of the βAR-sensitive cytokines, including CCL2 and TNF-α. Additionally, the impact of βAR-dependent EGFR transactivation on the acute regulation of cytokine transcript expression was assessed in isolated cardiomyocytes and in cardiac fibroblasts, where the majority of Iso-dependent, and EGFR-sensitive, changes in cytokines occurred. Overall, coincident with changes in cardiac structure and contractility, βAR stimulation dynamically alters cardiac transcript expression over time, including numerous cytokines that are regulated via EGFR-dependent signaling.
Effect of sodium tanshinone IIA sulfonate treatment in a rat model of preeclampsia
Authors: Morton Jude S. , Quon Anita , Cheung Po-Yin , Sawamura Tatsuya , Davidge Sandra T.
Published: December 2014

Preeclampsia is a disorder of pregnancy with a significant impact on maternal and fetal health. The complexity of this multifactorial condition has precluded development of effective therapies and, although many potential pathways have been investigated, the etiology still requires clarification. Our group has investigated the scavenger lectin-like oxidized LDL (LOX-1) receptor, which may respond to factors released from the distressed placenta that contribute to the vascular pathologies observed in preeclampsia. Given the known beneficial effects of sodium tanshinone IIA sulfonate (STS; a component of Salvia miltiorrhiza) on vasodilation, reduction of oxidative stress, and lipid profiles, we have investigated its role as a potential treatment strategy. We hypothesized that STS would improve vascular endothelial function and, combined with a reduction in oxidative stress, would improve pregnancy outcomes in a rat model of preeclampsia (reduced uteroplacental perfusion pressure, RUPP). We further hypothesized this may occur via the action of STS on the LOX-1 and/or platelet-activating factor (PAF) receptor axes. The RUPP model increased maternal blood pressure, vascular oxidative stress, and involvement of the vascular PAF receptor. Treatment with STS during pregnancy decreased both oxidative stress and involvement of the PAF receptor; however, it also increased involvement of the LOX-1 receptor, which is in line with the concept that scavenger receptors, such as LOX-1 and PAF, are upregulated in response to ligand binding and/or under pathological conditions. In this model of preeclampsia, however, the vascular actions of STS did not lead to improvements in pregnancy outcome such as fetal biometrics or maternal blood pressure.
Role of FAT/CD36 in fatty acid sensing, energy, and glucose homeostasis regulation in DIO and DR rats
Authors: Le Foll Christelle , Dunn-Meynell Ambrose A. , Levin Barry E.
Published: December 2014

Hypothalamic fatty acid (FA) sensing neurons alter their activity utilizing the FA translocator/receptor, FAT/CD36. Depletion of ventromedial hypothalamus (VMH) CD36 with adeno-associated viral vector expressing CD36 shRNA (AAV CD36 shRNA) leads to redistribution of adipose stores and insulin resistance in outbred rats. This study assessed the requirement of VMH CD36-mediated FA sensing for the regulation of energy and glucose homeostasis in postnatal day 5 (P5) and P21 selectively bred diet-induced obese (DIO) and diet-resistant (DR) rats using VMH AAV CD36 shRNA injections. P5 CD36 depletion altered VMH neuronal FA sensing predominantly in DIO rats. After 10 wk on a 45% fat diet, DIO rats injected with VMH AAV CD36 shRNA at P21 ate more and gained more weight than DIO AAV controls, while DR AAV CD36 shRNA-injected rats gained less weight than DR AAV controls. VMH CD36 depletion increased inguinal fat pad weights and leptin levels in DIO and DR rats. Although DR AAV CD36 shRNA-injected rats became as obese as DIO AAV controls, only DIO control and CD36 depleted rats became insulin-resistant on a 45% fat diet. VMH CD36 depletion stunted linear growth in DIO and DR rats. DIO rats injected with AAV CD36 shRNA at P5 had increased fat mass, mostly due to a 45% increase in subcutaneous fat. They were also insulin-resistant with an associated 71% increase of liver triglycerides. These results demonstrate that VMH CD36-mediated FA sensing is a critical factor in the regulation of energy and glucose homeostasis and fat deposition in DIO and DR rats.
Oxygen delivery-utilization mismatch in contracting locomotor muscle in COPD: peripheral factors
Authors: Medeiros Wladimir M. , Fernandes Mari C. T. , Azevedo Diogo P. , de Freitas Flavia F. M. , Amorim Beatriz C. , Chiavegato Luciana D. , Hirai Daniel M. , O'Donnell Denis E. , Neder J. Alberto
Published: December 2014

Central cardiorespiratory and gas exchange limitations imposed by chronic obstructive pulmonary disease (COPD) impair ambulatory skeletal muscle oxygenation during whole body exercise. This investigation tested the hypothesis that peripheral factors per se contribute to impaired contracting lower limb muscle oxygenation in COPD patients. Submaximal neuromuscular electrical stimulation (NMES; 30, 40, and 50 mA at 50 Hz) of the quadriceps femoris was employed to evaluate contracting skeletal muscle oxygenation while minimizing the influence of COPD-related central cardiorespiratory constraints. Fractional O2 extraction was estimated by near-infrared spectroscopy (deoxyhemoglobin/myoglobin concentration; deoxy-[Hb/Mb]), and torque output was measured by isokinetic dynamometry in 15 nonhypoxemic patients with moderate-to-severe COPD (SpO2 = 94 ± 2%; FEV1 = 46.4 ± 10.1%; GOLD II and III) and in 10 age- and gender-matched sedentary controls. COPD patients had lower leg muscle mass than controls (LMM = 8.0 ± 0.7 kg vs. 8.9 ± 1.0 kg, respectively; P < 0.05) and produced relatively lower absolute and LMM-normalized torque across the range of NMES intensities ( P < 0.05 for all). Despite producing less torque, COPD patients had similar deoxy-[Hb/Mb] amplitudes at 30 and 40 mA ( P > 0.05 for both) and higher deoxy-[Hb/Mb] amplitude at 50 mA ( P < 0.05). Further analysis indicated that COPD patients required greater fractional O2 extraction to produce torque (i.e., ↑Δdeoxy-[Hb/Mb]/torque) relative to controls ( P < 0.05 for 40 and 50 mA) and as a function of NMES intensity ( P < 0.05 for all). The present data obtained during submaximal NMES of small muscle mass indicate that peripheral abnormalities contribute mechanistically to impaired contracting skeletal muscle oxygenation in nonhypoxemic, moderate-to-severe COPD patients.
Tetrahydrobiopterin lowers muscle sympathetic nerve activity and improves augmentation index in patients with chronic kidney disease
Authors: Park Jeanie , Liao Peizhou , Sher Salman , Lyles Robert H. , Deveaux Don D. , Quyyumi Arshed A.
Published: December 2014

Chronic kidney disease (CKD) is characterized by overactivation of the sympathetic nervous system (SNS) that contributes to cardiovascular risk. Decreased nitric oxide (NO) bioavailability is a major factor contributing to SNS overactivity in CKD, since reduced neuronal NO leads to increased central SNS activity. Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase that increases NO bioavailability in experimental models of CKD. We conducted a randomized, double-blinded, placebo-controlled trial testing the benefits of oral sapropterin dihydrochloride (6R-BH4, a synthetic form of BH4) in CKD. 36 patients with CKD and hypertension were randomized to 12 wk of 1) 200 mg 6R-BH4 twice daily + 1 mg folic acid once daily; vs. 2) placebo + folic acid. The primary endpoint was a change in resting muscle sympathetic nerve activity (MSNA). Secondary endpoints included arterial stiffness using pulse wave velocity (PWV) and augmentation index (AIx), endothelial function using brachial artery flow-mediated dilation and endothelial progenitor cells, endothelium-independent vasodilatation (EID), microalbuminuria, and blood pressure. We observed a significant reduction in MSNA after 12 wk of 6R-BH4 (−7.5 ± 2.1 bursts/min vs. +3.2 ± 1.3 bursts/min; P = 0.003). We also observed a significant improvement in AIx (by −5.8 ± 2.0% vs. +1.8 ± 1.7 in the placebo group, P = 0.007). EID increased significantly (by +2.0 ± 0.59%; P = 0.004) in the 6R-BH4 group, but there was no change in endothelial function. There was a trend toward a reduction in diastolic blood pressure by −4 ± 3 mmHg at 12 wk with 6R-BH4 ( P = 0.055). 6R-BH4 treatment may have beneficial effects on SNS activity and central pulse wave reflections in hypertensive patients with CKD.
STE20/SPS1-related proline/alanine-rich kinase (SPAK) is critical for sodium reabsorption in isolated, perfused thick ascending limb
Authors: Cheng Chih-Jen , Yoon Joonho , Baum Michel , Huang Chou-Long
Published: December 2014

SPAK [STE20 (sterile 20)/SPS1-related proline/alanine-rich kinase] kinase consists of a full-length (FL-) and an alternatively spliced kidney-specific (KS-) isoform. SPAK regulates the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). The relative abundance and role of FL- vs. KS-SPAK in regulating Na+-K+-2Cl− cotransporter (NKCC2) in thick ascending limb (TAL) are not completely understood. Here, we report that FL-SPAK mRNA was the most abundant in medullary TAL (mTAL), followed by cortical TAL (cTAL) and DCT. KS-SPAK mRNA abundance was relatively lower than FL-SPAK. The ratios of FL-SPAK to KS-SPAK in mTAL, cTAL, and DCT were 12.3, 12.5, and 10.2, respectively. To examine the role of SPAK in the regulation of sodium transport in TAL, we used in vitro microperfusion of mTAL and cTAL isolated from wild-type (WT) and SPAK knockout mice (SPAK-KO) that lack both FL- and KS-SPAK. The rates of sodium absorption in cTAL and mTAL of SPAK-KO mice were 34.5 and 12.5% of WT tubules, respectively. The mRNA levels of related OSR1 kinase and SPAK protease Dnpep in SPAK-KO tubules were not significantly different from WT tubules. We next examined the role of SPAK in the regulation of sodium reabsorption by vasopressin in TAL. Vasopressin increased sodium reabsorption by ∼80% in both mTAL and cTAL from WT mice. While baseline sodium reabsorption was lower in SPAK-KO tubules, vasopressin increased sodium reabsorption over twofold. In conclusion, the combined net effect of SPAK isoforms on sodium reabsorption in TAL is stimulatory. SPAK is not essential for vasopressin stimulation of sodium reabsorption in TAL.
Hemodynamic basis for the limited renal injury in rats with angiotensin II-induced hypertension
Authors: Polichnowski Aaron J. , Griffin Karen A. , Picken Maria M. , Licea-Vargas Hector , Long Jianrui , Williamson Geoffrey A. , Bidani Anil K.
Published: December 2014

ANG II is thought to increase the susceptibility to hypertension-induced renal disease (HIRD) via blood pressure (BP)-dependent and BP-independent pathways; however, the quantitative relationships between BP and HIRD have not been examined in ANG II-infused hypertensive rats. We compared the relationship between radiotelemetrically measured BP and HIRD in Sprague-Dawley rats (Harlan) chronically administered ANG II (300–500 ng·kg−1·min−1, n = 19) for 4 wk versus another commonly employed pharmacological model of hypertension induced by the chronic administration of Nω-nitro-l-arginine methyl ester (l-NAME, 50 mg·kg−1·min−1, n = 23). Despite the significantly higher average systolic BP associated with ANG II (191.1 ± 3.2 mmHg) versus l-NAME (179.9 ± 2.5 mmHg) administration, the level of HIRD was very modest in the ANG II versus l-NAME model as evidenced by significantly less glomerular injury (6.6 ± 1.3% vs. 11.3 ± 1.5%, respectively), tubulointerstitial injury (0.3 ± 0.1 vs. 0.7 ± 0.1 injury score, respectively), proteinuria (66.3 ± 10.0 vs. 117.5 ± 10.1 mg/day, respectively), and serum creatinine levels (0.5 ± 0.04 vs. 0.9 ± 0.07 mg/dl, respectively). Given that HIRD severity is expected to be a function of renal microvascular BP transmission, BP-renal blood flow (RBF) relationships were examined in additional conscious rats administered ANG II ( n = 7) or l-NAME ( n = 8). Greater renal vasoconstriction was observed during ANG II versus l-NAME administration (41% vs. 23% decrease in RBF from baseline). Moreover, administration of ANG II, but not l-NAME, led to a unique BP-RBF pattern in which the most substantial decreases in RBF were observed during spontaneous increases in BP. We conclude that the hemodynamic effects of ANG II may mediate the strikingly low susceptibility to HIRD in the ANG II-infused model of hypertension in rats.
Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways
Authors: Dideriksen Jakob L. , Muceli Silvia , Dosen Strahinja , Laine Christopher M. , Farina Dario
Published: December 2014

Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions.