bluuebunny/crossref_metadata_2025 huggingface dataset:
Axisymmetric Low-Reynolds Motion of Drops Through Circular Microchannels
Authors: Pineda Saira F. , Kamp Arjan M. , Legendre D. , Blanco Armando J.
Published: July 2013

Flow constituted by drops appears in a wide range of natural, biological and engineering situations. For example, liquid-liquid two phase flow inside capillaries constitutes a model commonly used to represent fluid flow in a petroleum reservoir. The typical modeling approach considers inertial forces negligible in comparison to viscous forces, allowing the use of Stokes equation to study flow dynamics. Very few numerical simulations have been made considering inertial effects. In this project, the flow of a periodic train of drops in a viscous suspending fluid, due to the influence of a fixed pressure gradient, was studied by numerical simulation considering the full Navier-Stokes equations.

A numerical approach based on a Volume of Fluid (VOF) formulation was employed using JADIM software, developed by the Institut de Mécanique des Fluides de Toulouse, France. JADIM solves Navier-Stokes equations using a VOF finite volume method, second order in space and time using structured mesh. This two-fluid approach without reconstruction of the interface allows simulating two-phase flows with complex interface shapes.

Densities of the drops equal to those of the suspending fluid and a constant interface tension were assumed. The effect of drop size, viscosity ratio, interfacial forces and system pressure gradient on the flow dynamics was studied. Parameters values were chosen to be representative for some particular viscous oil.

The result validation shows an excellent agreement between both numerical results. However, there are relative differences between them due to the increase in flow velocity when drop relative size increase and validity of Stokes approach is questionable.

Results show non-symmetric eddies in the continuum phase, in a referential frame fixed to the drop. The shape of eddies is strongly influenced by viscosity radio. Drop mobility decreases with increasing size. Additionally, drop mobility also decreases when the viscosity ratio increases. Extra pressure gradient of the system due to the presence of the drop shows a strong dependency on the size ratio between the drop and the pore. For size ratio lower than 0.5, the extra pressure gradient required to move the continuum phase is small. However, when drop to micro-channel ratio exceeds 0.5, the extra pressure gradient significantly increases when the drop size increases. Also, viscosity ratio affects on the system pressure loss, especially in cases where the viscosity ratio is high. The analysis of the capillary number effect on the dynamics of the two-phase system shows that it does not influence drop mobility for the drop sizes considered.
Hydrophobicity of Nanostructured Films Characterized by a Quartz Crystal Microbalance
Authors: Wang Pengtao , Charmchi Majid , Shen Mengyan , Sun Hongwei
Published: July 2013

The hydrophobicity of two types of nanostructured polymer films were fabricated and characterized with a novel quartz crystal microbalance (QCM) technique to investigate their static and dynamic hydrophobic properties. The nanofibrous films of polymethylmethacrylate (PMMA), PMMA/Polydimethylsiloxane (PDMS) and Polyacrylonitril (PAN) were prepared with an electrospinning process and a PMMA film with nanoscale roughness was fabricated using nanoimprint lithography (NIL) technique. Significantly different static and dynamic hydrophobicities (wettability) were found among these films and the correlation between hydrophobicity and the mechanical impedance of QCM to these films were developed both experimentally and theoretically. It was shown that QCM is capable of quantitatively characterizing the hydrophobicity of these nanostructured polymer surfaces. For nanofibrous films, the double layers — a viscoelastic nanofiber film and a liquid layer result in a nonlinear combination of mechanical impedances of QCM. To simplify the analysis, an apparent viscosity was introduced in the analysis to take into account the interactions between liquid and polymer surfaces. For NIL PMMA film, the hydrophobicity was altered by coating nano-roughened surface with a Teflon layer. The reduction in the mechanical impedance of QCM clearly demonstrates the enhancement of hydrophobicity. The experimental results showed that the hydrophobic surface lead to a small mechanical impedance while the hydrophilic surface resulted in a large mechanical impedance of QCM.
A QCM-Based Lab-on-a-Chip Device for Real Time Characterization of Shear-Induced Platelets Adhesion and Aggregation
Authors: Sun Hongwei , Wang Pengtao , Liu Moli , Xu Jin
Published: July 2013

The long-term goal of this project is to develop a microfluidic device integrated with a quartz crystal microbalance (QCM) sensor to perform real-time monitoring of platelet adhesion and aggregation under various hemodynamic conditions. This Lab-On-a-Chip device was fabricated with softlithography technique and plasma bonding. The gold sensing surface (electrode) of QCM sensor was embedded in the sensing area of microchannel, in which different fluid solutions were driven through to induce required shear flows for protein interaction study. The time-dependent (transient) frequency shift upon flowing blood samples was monitored to characterize the dynamic process of the platelet adhesion and protein interaction. The interaction between recombinant platelet surface receptor glycoprotein Ibα (GPIbα) and von Willebrand factor (vWF) were investigated under both static and dynamic flow conditions. It was found that the association process is much faster than disassociation process. This device functions as a powerful platform for studying the impact of flow pattern and shear stress on platelet function and GPIbα and vWF interaction, and potentially serves as a prototype for cardiovascular diagnostic purposes.
Experimental Investigation of the Flow Front Behind a Liquid-Air Interface for Capillary Flow
Authors: Waghmare Prashant R. , Sen Debjyoti , Nobes David S. , Mitra Sushanta K.
Published: July 2013

An experimental system for understanding the flow field near the meniscus during the capillarity or under capillary action is developed. Capillary flow is one of the mechanisms for driving fluid in a microfluidic device. The literature highlights that a significant amount of work has been done on the theoretical understanding of the capillary transport in rectangular microchannels. However, these models for capillary flow neglect the flow behavior at the liquid-air interface, which may have a significant influence in terms of the velocity field and the transience of the penetration depth in the micro-capillary. The objective of the present study is to understand the flow development during the advancement of the meniscus. The aim is to elucidate the dynamics of the three phase contact line and other micro-scale effects during the capillarity. A μ-PIV technique has been used to study the flow development near the meniscus and the results are further refined using a hybrid μ-PIV/PTV technique. Effects of surface tension in the fully developed flow regime during the advancement of meniscus are studied in detail. Variations in the centreline velocity of the progression of the meniscus and temporal variations in the development of flow are identified as possible areas for departure from theory.
Single-Phase Heat Transfer in a Multiport Minichannel Tube-in-Tube Heat Exchanger
Authors: Kaew-On Jatuporn , Wongwises Somchai
Published: July 2013

In the present work, the single-phase heat transfer of water flowing through the multiport minichannel heat exchanger was experimentally studied. The inner tube was made from the extruded multiport aluminum tube with hydraulic diameter of 1.1mm and the 14 number of channel, while the outer tube was made from the acrylic circular tube with an internal hydraulic diameter of 25.4 mm. The single-phase heat transfer performance is experimentally determined based on the water-to-water operation. The experiments have been carried out by varying flow rates and temperatures of water on both sides. The Reynolds numbers were approximately 500–4000 on the inner tube and 1000–5000 on the outer tube. The LMTD method was employed to investigate the heat transfer and the experimental results were compared with the existing correlations from the literature. Finally, the Nusselt number correlation for single-phase flow of the water flowing through the multiport minichannel has also been proposed.
The Rules of Single-Phase Forced Convection in Microchannels
Authors: Morini Gian Luca
Published: July 2013

This paper deals with the experimental analysis of forced micro-convection features of liquid and gas flows through microchannels. An overview of the main effects that tends to play an important role on the determination of the Nusselt numbers in microchannels is presented. Some experimental data obtained at the Microfluidics Lab of the University of Bologna together with the main results appeared recently in the open literature are used in order to highlight the characteristics of the convective heat transfer through microchannels with inner diameter from 0.75 mm down to and 0.15 mm. It is shown that the behavior of gas and liquid flows through microchannels in terms of convective heat transfer coefficients can be strongly affected by scaling and micro-effects as by practical issues linked to the geometry of the test rig, fittings, position of the sensors and so on. It is demonstrated that the comparison with the conventional correlations for the prediction of the convective heat transfer coefficients gives good results only if one has verified beforehand that the main scaling and micro-effects are negligible.
Compact Model Based Microfluidic Controller for Energy Efficient Thermal Management of Single Tier and 3D Chips
Authors: Han Xuefei , Joshi Yogendra K.
Published: July 2013

Over-cooling of electronic devices and systems results in excess energy consumption, which can be reduced by closely linking cooling requirements with actual power dissipation. A thermal model-based real-time flow rate controller for pin-fin micro channel liquid cooling for planar and 3D stacked chips was studied in this paper to optimize cooling power. A thermal compact model of single layer and two layers fin enhanced micro-channel was developed, which ran 105 times faster than using CFD method, with reasonable accuracy. This was used in conjunction with a flow rate control strategy to provide the needed amount of liquid to cool the heat source to the desired temperature range.
Fluid Flow and Heat Transfer Simulations of the Cooling-Water Channel in a Tera-Hertz Radiation Detector
Authors: Tohid Usama , Pacheco-Vega Arturo , Tikhoplav Rodion , Ruelas Marcos
Published: July 2013

Detailed numerical simulations have been carried out to find the velocity and temperature fields of a rectangular channel with large aspect-ratio. The channel under analysis is aimed to cool a thermo-chromic liquid crystal material (TLC) that is able to capture laser irradiation in the terahertz range. The overall objective of the cooling system is to maintain a nearly-homogeneous temperature of the TLC layer that is not exposed to the direct laser irradiation. The fluid flow and heat transfer simulations are carried out on the basis of three-dimensional versions of the Navier-Stokes equations, along with the energy equation, for an incompressible flow, to determine values of velocity, pressure and temperature inside the channel under different operating conditions. These values are then used to find, from a specific set, the value of the channel height that allows for the most uniform temperature distribution within the expected operating conditions. Results from this analysis indicate that, for all the inlet velocities considered, there is a common value of the channel height, that represents the optimum.
Enhanced Convective Mixing and Residence Time Distribution in Advanced Micromixers
Authors: Fischer Maximilian , Kockmann Norbert
Published: July 2013

Homogeneous mixing of liquids in microchannels is well known and characterized for simple channel geometries, such as Y- or T-shaped mixers. Also meandering mixing channels, in which Dean vortices are generated, are often employed to achieve rapid mixing of liquids. A CFD study was performed to increase the mixing performance in the contacting and first mixing element. Dean vortices in the inlet channels increase the mixing quality for Re numbers in the range from 20 to 200 together with S-shaped mixing elements. Mixing quality is significantly increased by a factor of 2 to more than 5 compared to a T-shaped mixer. The residence time distribution is a further important parameter, which is investigated in this contribution.
Experimental Investigation of Mixing in a T-Channel for Asymmetric Inlet Conditions
Authors: Basavarajappa Manjunath , Elsnab John , Thomas Susan , Ameel Timothy A.
Published: July 2013

An experimental investigation of water flow in a rectangular T-channel with inner dimensions of 20 × 20 mm (inlet channel) and 20 × 40 mm (outlet mixing channel) has been conducted. The inlet Reynolds number Re, based on inlet hydraulic diameter, ranged from Re1 = 90 to 775. Inlet flow conditions were asymmetric, and inlet Re ratios of Re1/Re2 = 1.24, 1.65 and 2.45 were obtained by varying volumetric flow rate. Dynamical conditions and T-channel geometry are directly applicable to microscale mixing. Planar laser induced fluorescence (LIF) was used to characterize flow regimes and behaviors, including periodicity, in the inlet and outlet channels. Two distinct flow regimes were identified and characterized for asymmetric inlet Re. For low inlet Re, Re1 ≤ 150, and all Re1/Re2, flows were steady. For higher Re and all Re1/Re2, a jet flow regime, characterized by two counter rotating vortices and increasingly turbulent at higher Re dominated the flow in the junction. Qualitative mixing characteristics for all flow regimes, based on LIF visualizations in the outlet channel, are also presented.
Numerical Investigations of Digitized Heat Transfer
Authors: Zhang Peter , Mohseni Kamran
Published: July 2013

In the rapidly evolving field of high-powered electronics, hardware continues to become smaller and more powerful. The consequence of this trend is tightly packed electronic components and high heat generation rates that demands more efficient thermal management techniques. In this paper, digitized heat transfer using electrowetting on a dielectric is examined as a potential solution. A numerical simulation of translating microdroplets in a parallel plate and axisymmetric pipe is studied. From previous studies, it is known that translating microdroplets have improved heat transfer over continuous flow that is highly dependent on the height to length ratio of the droplet. This paper finds that in addition to the height to length ratio, Reynolds numbers has a significant effect on droplet velocity profile as well as droplet temperature distribution. At high Reynolds numbers, the center line velocity increases beyond what is predicted in a Poiseuille flow, thus increasing circulation and the Nusselt number of the droplet. Additionally, it is found that the center line velocity enhancement is accompanied by the development of inflection points in the velocity profile, indicating more susceptibility to instability development and potential transition to turbulence. Nevertheless, the change in Reynolds number was found to not have a significant effect on the location of the Nusselt number peaks along the channel length which is correlated with the circulation length of the droplet.
Evaluation of Nusselt Number for a Flow in a Microtube With Second-Order Model Including Thermal Creep
Authors: Çetin Barbaros
Published: July 2013

In this paper, Nusselt number for a flow in a microtube is determined analytically with a constant wall heat flux thermal boundary condition. The flow assumed to be incompressible, laminar, hydrodynamically and thermally fully-developed. The thermo-physical properties of the fluid are assumed to be constant. The effect of rarefaction, viscous dissipation, axial conduction, which are important at the microscale, are included in the analysis. For the implementation of the rarefaction effect, two different second-order slip models are used for the slip-flow and temperature-jump boundary conditions together with the thermal creep at the wall. Closed form solutions for the fully-developed temperature profile and Nusselt number are derived as a function of Knudsen number, Brinkman number and Peclet number.
Progress and issues in e-beam and other top down nanolithography
Authors: Tennant Donald M.
Published: July 2013

In this 60th anniversary year of the American Vacuum Society (AVS), this paper is one in a series of topical reviews of science and technology represented by the various AVS Divisions. The focus of the paper is on trends, frontier advancement, and issues remaining in nanolithography. The manuscript highlights,in particular, the progress made in electron beamlithographysystem development, advancement in materials and methods used to pattern down to a few nanometers, and the prospects for multiple beamsystems as high throughput alternatives. Also discussed are the underlying rationales for observed trends in lithography tool development. Invariably the discussion about emerging lithographysolutions bifurcates depending on whether one is examining the roadmap for the silicon integrated circuit industry or everything else. The emphasis here is mostly on everything else but also explores the boundary.
Level-set-based inverse lithography for mask synthesis using the conjugate gradient and an optimal time step
Authors: Lv Wen , Liu Shiyuan , Xia Qi , Wu Xiaofei , Shen Yijiang , Lam Edmund Y.
Published: July 2013

Inverse mask synthesis is achieved by minimizing a cost function on the difference between the output and desired patterns. Such a minimization problem can be solved by a level-set method where the boundary of the pattern is iteratively evolved. However, this evolution is time-consuming in practice and usually converges to a local minimum. The velocity of the boundary evolution and the size of the evolution step, also known as the descent direction and the step size in optimization theory, have a dramatic influence on the convergence properties. This paper focuses on developing a more efficient algorithm with faster convergence and improved performance such as smaller pattern error, lower mean edge placement error, wider defocus band, and higher normalized image log slope. These improvements are accomplished by employing the conjugate gradient of the cost function as the evolution velocity, and by introducing an optimal time step for each iteration of the boundary evolution. The latter is obtained from an extended Euler time range by using a line search method. The authors present simulations demonstrating the efficacy of these two improvements.
Microstructure and mechanical properties of Ti–B–C–N–Si nanocomposite films deposited by unbalanced magnetron sputtering
Authors: Jang Jaeho , An Eunsol , Park In-Wook , Nam Dae-Geun , Jo Ilguk , Lin Jianliang , Moore John J. , Ho Kim Kwang , Park Ikmin
Published: July 2013

Quinary Ti–B–C–N–Si nanocomposite thin films were deposited on AISI 304 stainless steel substrates by d.c. unbalanced magnetron sputtering from a TiB2–TiC compound target and a pure Si target. The relationship between microstructure and mechanical properties of the films was investigated in terms of the nanosized crystallites/amorphous system. The synthesized Ti–B–C–N–Si films were characterized using x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, and high resolution transmission electron microscopy. The results showed that the Ti–B–C–N–Si films were nanocomposites composed of nanosized TiB2, TiC, and TiSi2 crystallites (2-3 nm in size) embedded in an amorphous matrix. The addition of Si to the Ti–B–C–N film led to precipitation of nanosized crystalline TiSi2 and percolation of amorphous SiC phases. The Ti–B–C–N–Si films with up to 7 at. % Si content presented high hardness (≥35 GPa), H/E (≥0.0095), and We (>50%) with compressive residual stress (∼0.5 GPa). A systematic investigation on the microstructure and mechanical properties of Ti–B–C–N–Si films containing different Si contents is reported.
Central giant cell granuloma: a case report
Authors: Mohan Ravi Prakash Sasankoti , Verma Sankalp , Agarwal Neha , Singh Udita
Published: July 2013

Central giant cell granuloma (CGCG) is a relatively uncommon benign bony lesion of a variably aggressive nature. Thought to represent a reparative response to intrabony haemorrhage and inflammation, CGCG was once regarded as a reactive lesion. It is actually an asymptomatic lesion which becomes evident during routine radiographic examination or as a result of painless but visible expansion of the affected jaw. This paper presents the case of a 4-year-old boy with  CGCG in the right mandibular region.
Keratinous inclusion cyst of oesophagus: unusual finding
Authors: Wan Abdul Rahman Wan Faiziah , Mutum Samarendra Singh , Fauzi Mohd Hashairi
Published: July 2013

Cysts of the oesophagus are unusual findings and they are classified according to the embryological site of origin. It may represent inclusion cysts, retention cysts and developmental cysts. We present a case of keratinous inclusion cyst of the lower oesophagus in a 71-year-old Malay woman who presented with dyspepsia and severe epigastric pain. An oesophago-gastro-duodenoscopy demonstrated a sliding hiatus hernia with whitish ulcer-like lesion at the lower oesophagus. Biopsy from the lesion revealed a keratinous inclusion cyst. The patient was given pantoprazole and put on regular follow-up for monitoring any other development.
Vps1, a recycling factor for the traffic from early endosome to the late Golgi
Authors: Lukehart Joshua , Highfill Chad , Kim Kyoungtae
Published: July 2013

Recycling of cellular membranes and their constituents plays a role for cell survival and growth. In the budding yeast, there are recycling traffics from early and late endosomal compartments to the late Golgi. Here, we examined a possible role for Vps1, a large GTPase, in the recycling traffic of GFP-Snc1 from early endosomes to the late Golgi. In the absence of Vps1 we observed an aberrant accumulation of GFP-Snc1 puncta in the cytoplasm that we identified as early endosomes. The N-terminal GTPase and the C-terminal GED domains of Vps1 are essential for Vps1’s function in Snc1 recycling. Our finding of genetic interactions of VPS1 with genes involved in early endosome-to-Golgi traffic further suggests Vps1 functions as a recycling factor in the membrane traffic. Finally, we provide evidence that the severe accumulation of GFP-Snc1 cytoplasmic puncta in vps1Δ cells is attributed to a mild defect in the retention of the GARP component Vps51 at the late Golgi, as well as a severe disruption of actin cables.
Performance of steel buildings and nonstructural elements during the 27 February 2010 Maule (Chile) Earthquake
Authors: Saatcioglu Murat , Tremblay Robert , Mitchell Denis , Ghobarah Ahmed , Palermo Dan , Simpson Rob , Adebar Perry , Ventura Carlos , Hong Hanping
Published: July 2013

This paper presents performance of steel buildings and nonstructural elements during the 27 February 2010 Maule Earthquake in Chile. Structural steel buildings are not common in Chile, due to the relatively high cost of material. The majority of damage to steel structures was observed in industrial facilities. In general, the structural steel buildings performed well. Limited damage was observed in some of the older buildings. Extensive damage was sustained by nonstructural elements, including masonry infill walls, suspended ceilings, partition walls, and architectural features. Brick masonry partition walls, commonly used in Chilean buildings, suffered damage when used in frame buildings with little drift control. The paper presents a summary of observed damage and a comparison of Chilean and Canadian design practices for steel buildings, with lessons drawn from observed structural performance.
Alpha to gamma mode transition in hydrogen capacitive radio-frequency discharge
Authors: Abdel-Fattah E. , Farag Omar F.
Published: July 2013

Electron energy distribution functions (EEDFs) were measured with increasing discharge voltages in hydrogen capacitively coupled plasmas by means of radio-frequency compensated Langmuir probe. The results are compared with EEDF in argon plasmas. It was found that, in the hydrogen capacitive discharge, abnormally low-energy electrons became highly populated and the EEDF evolved to a non-Maxwellian distribution as the discharge voltage was increased. This voltage dependence of the EEDF in the hydrogen is contrary to argon capacitively coupled plasma, where at high discharge voltage, low-energy electrons are significantly thermalized due to γ heating and the EEDF evolves to the Maxwellian distribution. The highly populated low-energy electrons at high gas pressure, which was not observed in capacitively coupled argon plasma, show that the γ heating mechanism is somehow inefficient in terms of the molecular gas in capacitive discharges. It appears that this inefficient γ heating seems to be attributed to an efficient vibrational excitation in hydrogen capacitive plasma.
Co-agonist of glucagon and GLP-1 reduces cholesterol and improves insulin sensitivity independent of its effect on appetite and body weight in diet-induced obese C57 mice
Authors: Patel Vishal , Joharapurkar Amit , Dhanesha Nirav , Kshirsagar Samadhan , Patel Kartik , Bahekar Rajesh , Shah Gaurang , Jain Mukul
Published: July 2013

Dual agonism of glucagon and glucagon-like peptide-1 (GLP-1) receptors reduce body weight without inducing hyperglycemia in rodents. However, the effect of a co-agonist on insulin sensitivity and lipid metabolism has not been thoroughly assessed. Diet-induced obese (DIO) mice received 0.5 mg·kg–1 of co-agonist or 2.5 mg·kg–1 of glucagon or 8 μg·kg–1 of exendin-4 by subcutaneous route, twice daily, for 28 days. A separate group of mice was pair-fed to the co-agonist-treated group for 28 days. Co-agonist treatment reduced food intake and reduced body weight up to 28 days. In addition, it reduced leptin levels and increased fibroblast growth factor 21 (FGF21) levels in plasma, when compared with control and pair-fed groups. Co-agonist treatment decreased triglyceride levels in serum and liver and reduced serum cholesterol, mainly due to reduction in low-density lipoprotein (LDL) cholesterol. These changes were not seen with pair-fed controls. Co-agonist treatment improved glucose tolerance and increased insulin sensitivity, as observed during glucose and insulin-tolerance test, hyperinsulinemic clamp, and reduced gluconeogenesis, as observed in pyruvate-tolerance test. The effects on insulin sensitivity and lipid levels are mostly independent of the food intake or body weight lowering effect of the co-agonist.
VON NEUMANN ENTROPY AND RELATIVE POSITION BETWEEN SUBALGEBRAS
Authors: CHODA MARIE
Published: July 2013

In order to give numerical characterizations of the notion of "mutual orthogonality", we introduce two kinds of family of positive definite matrices for a unitary u in a finite von Neumann algebra M. They are arising from u naturally depending on the decompositions of M. One corresponds to the tensor product decomposition and the other does to the crossed product decomposition. By using the von Neumann entropy for these positive definite matrices, we characterize the notion of mutual orthogonality between subalgebras.
PARABOLIC GEODESICS AS PARALLEL CURVES IN PARABOLIC GEOMETRIES
Authors: HERZLICH MARC
Published: July 2013

We give a simple characterization of the parabolic geodesics introduced by Čap, Slovák and Žádník for all parabolic geometries. This goes through the definition of a natural connection on the space of Weyl structures. We then show that parabolic geodesics can be characterized as the following data: a curve on the manifold and a Weyl structure along the curve, so that the curve is a geodesic for its companion Weyl structure and the Weyl structure is parallel along the curve and in the direction of the tangent vector of the curve.
A MODIFIED IMPROVED RUNGE–KUTTA FIFTH-ORDER FIVE STAGE TECHNIQUE TO STUDY INDUSTRIAL ROBOT ARM
Authors: SENTHILKUMAR SUKUMAR , LEE MALREY , JEONG GISUNG
Published: July 2013

A new alternative way named modified improved Runge-Kutta fifth-order five stage (MIRK(5,5)) technique is employed to compute a second-order robot arm problem and also for variations in angles of a robot arm joints model, which needs less number of function evaluations per time step, is the main focus of this paper. Numerically computed outputs match with the exact solution of the industrial robot arm problem which in turn shows that MIRK(5,5) algorithm are better to solve real-time problems practically.
PREPARATION AND MECHANISM OF CONTROLLABLE MICROPORES ON BIOCERAMIC TiO2 COATINGS BY PLASMA ELECTROLYTIC OXIDATION
Authors: WANG HONG-YUAN , ZHU RUI-FU , LU YU-PENG , XIAO GUI-YONG , MA JIE , YUAN Y. F.
Published: July 2013

Porous titania coatings with Ca and P elements were synthesized by plasma electrolytic oxidation (PEO). The treatment was carried out in an electrolyte containing calcium acetate monohydrate and disodium phosphate dodecahydrate ( Ca / P = 5), and 4–20 μm micropores were prepared on the coatings by applied pulse frequencies of 200–1000 Hz. The surface structure, chemical composition of the TiO 2 coatings, and time-dependent variation of electric currents were studied. The result revealed that the coating micropores, which could be controlled in size, increased with higher frequency, and the coatings mainly consisted of anatase and rutile phases with varying fractions. Based on our experiment, the formation mechanism of micropores and phases of the PEO coatings was further discussed in details.
AN ARBITRATED QUANTUM SIGNATURE SCHEME BASED ON HYPERCHAOTIC QUANTUM CRYPTOSYSTEM
Authors: GUO YING , SUN XIN , ZHANG WEI
Published: July 2013

A chaos-based arbitrated quantum signature (AQS) scheme is designed on the basis of an improved quantum chaotic encryption algorithm whose security is ensured due to the implementation of the quantum one-time pad that embraces the key-dependent chaotic operation string. It involves in a small-scale quantum computation network with three participants in three phases, i.e. initializing phase, signing phase and verifying phase. The signatory signs the encrypted message and then the receiver verifies the signature is valid with the aid of an arbitrator who plays a crucial role when a dispute arises. Analysis shows that the signature can neither be forged nor disavowed by the malicious attackers.
DETECTING BILATERAL FUNCTIONAL CONNECTIVITY IN THE PREFRONTAL CORTEX DURING A STROOP TASK BY NEAR-INFRARED SPECTROSCOPY
Authors: ZHANG LEI , SUN JINYAN , SUN BAILEI , GAO CHENYANG , GONG HUI
Published: July 2013

Near-infrared spectroscopy (NIRS) is generally accepted as a functional brain imaging technology for brain activation study. With multichannel highly sensitive NIRS instruments, it has become possible to assess functional connectivity of different brain regions by NIRS. However, the feasibility needs to be validated in complex cognitive activities. In this study, we recorded the hemodynamic activity of the bilateral prefrontal cortex (PFC) during a color-word matching Stroop task. Wavelet transform coherence (WTC) analysis was applied to assess the functional connectivity of all homologous channel pairs within the left/right PFC. Both the behavioral and brain activation results showed significant Stroop effects. The results of WTC analysis revealed that, bilateral functional connectivity was significantly stronger during both the incongruent stimuli and neutral stimuli compared to that of the rest period. It also showed significant Stroop effect. Our findings demonstrate that, NIRS becomes a valuable tool to elucidate the functional connectivity of brain cortex in complex cognitive activities.
NANOMATERIALS FOR PROTEIN-MEDIATED THERAPY AND DELIVERY
Authors: BARRY JOHN N. , VERTEGEL ALEXEY A.
Published: July 2013

There has been a significant amount of research done on liposomes and nanoparticles as drug carriers for protein drugs. Proteins and enzymes have been used both as targeting moieties and for their therapeutic potential. High specificity and rapid reaction rates make proteins and enzymes excellent candidates for therapeutic treatment, but some limitations exist. Many of these limitations can be addressed by a well-studied nanotechnology-based delivery system. Such a system can provide a medium for delivery, stabilization of the drugs, and enable site-specific accumulation of drugs. Nanomedicines such as these have great potential to revolutionize the pharmaceutical industry and improve healthcare worldwide.
Microtubules in Cell Migration
Authors: Etienne-Manneville Sandrine
Published: July 2013

Migration is a polarized cellular process that opposes a protrusive front edge to a retracting trailing edge. From the front to the rear, actin-mediated forces sequentially promote cell protrusion, adhesion, contraction, and retraction. Over the past decade, microtubules have revealed their pivotal role in cell migration. Through their roles in cell mechanics, intracellular trafficking, and signaling, microtubules participate in all essential events leading to cell migration. The front-rear polarization of microtubule functions relies on the asymmetric regulation of microtubule dynamics and stability; the asymmetric distribution of microtubule-associated protein complexes; and finally, the orientation of the microtubule network along the axis of migration. Microtubule network polarity controls the establishment and maintenance of the spatial and temporal coordination of migration events and is therefore the key to persistent directed migration. This review summarizes our current understanding of the functions of microtubules in persistent cell migration and of the migration-associated signals that promote microtubule network polarization.
Hormonal Control of Stem Cell Systems
Authors: Gancz Dana , Gilboa Lilach
Published: July 2013

Many organs respond to physiological challenges by changing tissue size or composition. Such changes may originate from tissue-specific stem cells and their supportive environment (niche). The endocrine system is a major effector and conveyor of physiological changes and as such could alter stem cell behavior in various ways. In this review, we examine how hormones affect stem cell biology in four different organs: the ovary, intestine, hematopoietic system, and mammary gland. Hormones control every stage of stem cell life, including establishment, expansion, maintenance, and differentiation. The effects can be cell autonomous or non–cell autonomous through the niche. Moreover, a single hormone can affect different stem cells in different ways or affect the same stem cell differently at various developmental times. The vast complexity and diversity of stem cell responses to hormonal cues allow hormones to coordinate the body's reaction to physiological challenges.
microRNA Control of Mouse and Human Pluripotent Stem Cell Behavior
Authors: Greve Tobias S. , Judson Robert L. , Blelloch Robert
Published: July 2013

In the past decade, significant progress has been made in understanding both microRNA function and cellular pluripotency. Here we review the intersection of these two exciting fields. While microRNAs are not required for the establishment and maintenance of pluripotency in early development and cell culture, respectively, they are critically important in the regulation of the cell cycle structure of pluripotent stem cells as well as the silencing of the pluripotency program upon differentiation. Pluripotent cells, both in vivo and in vitro, dominantly express a single family of microRNAs, which can promote the reprogramming of a somatic cell back to a pluripotent state. Here, we review the known mechanisms by which these and other microRNAs regulate the different aspects of the pluripotent stem cell program in both mouse and human.
Growing Up in the Genomic Era: Implications of Whole-Genome Sequencing for Children, Families, and Pediatric Practice
Authors: Wade Christopher H. , Tarini Beth A. , Wilfond Benjamin S.
Published: July 2013

Whole-genome sequencing (WGS) has advanced to a point where it is beginning to be integrated into pediatric practice. With little consensus on how to maximize the benefits of WGS for children, there is a growing need for focused efforts that connect researchers, clinicians, and families to chart a path forward. To illustrate relevant concerns, two contrasting applications of pediatric WGS are explored: clinical use with children who have undiagnosed conditions, and population-based screening. Specific challenges for health care services, policy development, and the well-being of children are discussed in light of current research. In the interest of ensuring evidence-based pediatric WGS, strategies are identified for advancing our understanding of what it means for children to grow up with WGS results guiding their health care.
Major Histocompatibility Complex Genomics and Human Disease
Authors: Trowsdale John , Knight Julian C.
Published: July 2013

Over several decades, various forms of genomic analysis of the human major histocompatibility complex (MHC) have been extremely successful in picking up many disease associations. This is to be expected, as the MHC region is one of the most gene-dense and polymorphic stretches of human DNA. It also encodes proteins critical to immunity, including several controlling antigen processing and presentation. Single-nucleotide polymorphism genotyping and human leukocyte antigen (HLA) imputation now permit the screening of large sample sets, a technique further facilitated by high-throughput sequencing. These methods promise to yield more precise contributions of MHC variants to disease. However, interpretation of MHC-disease associations in terms of the functions of variants has been problematic. Most studies confirm the paramount importance of class I and class II molecules, which are key to resistance to infection. Infection is likely driving the extreme variation of these genes across the human population, but this has been difficult to demonstrate. In contrast, many associations with autoimmune conditions have been shown to be specific to certain class I and class II alleles. Interestingly, conditions other than infections and autoimmunity are also associated with the MHC, including some cancers and neuropathies. These associations could be indirect, owing, for example, to the infectious history of a particular individual and selective pressures operating at the population level.
The RASopathies
Authors: Rauen Katherine A.
Published: July 2013

The RASopathies are a clinically defined group of medical genetic syndromes caused by germline mutations in genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. These disorders include neurofibromatosis type 1, Noonan syndrome, Noonan syndrome with multiple lentigines, capillary malformation–arteriovenous malformation syndrome, Costello syndrome, cardio-facio-cutaneous syndrome, and Legius syndrome. Because of the common underlying Ras/MAPK pathway dysregulation, the RASopathies exhibit numerous overlapping phenotypic features. The Ras/MAPK pathway plays an essential role in regulating the cell cycle and cellular growth, differentiation, and senescence, all of which are critical to normal development. Therefore, it is not surprising that Ras/MAPK pathway dysregulation has profound deleterious effects on both embryonic and later stages of development. The Ras/MAPK pathway has been well studied in cancer and is an attractive target for small-molecule inhibition to treat various malignancies. The use of these molecules to ameliorate developmental defects in the RASopathies is under consideration.
The European Union Emissions Trading Scheme: Issues in Allowance Price Support and Linkage
Authors: Convery Frank J. , Redmond Luke
Published: July 2013

In 2008, the European Union established what seemed like an ambitious cap (−21% from 2005 levels) for the third phase (2013–2020) of the European Union Emissions Trading Scheme (EU ETS). Ex ante modeling—which took account of the reductions in emissions resulting from meeting the renewables target and the inflow of project-based credits—indicated that this would result in an approximate allowance price of €30 per tonne of CO2, which was judged to provide the necessary financial incentive to abate emissions, to support carbon capture and storage and innovation in alternative energy supplies, and to discourage member states from doing their own thing in terms of price support and other measures. The only linkage was the acceptance for compliance purposes of Clean Development Mechanism and Joint Implementation credits. But in 2013, all has changed; the allowance price is approximately 75% less than what was anticipated, a friends-of-coal lobby has emerged in the EU, and opportunities to link with other ETS are now becoming a reality. This article tells the story of the allowance price collapse, emerging opportunities for linkage—including promising developments in China—and what recent literature has to offer in both understanding the past and informing the future.
Children with Generalised Joint Hypermobility and Musculoskeletal Complaints: State of the Art on Diagnostics, Clinical Characteristics, and Treatment
Authors: Scheper M. C. , Engelbert R. H. H. , Rameckers E. A. A. , Verbunt J. , Remvig L. , Juul-Kristensen B.
Published: July 2013

Introduction. To provide a state of the art on diagnostics, clinical characteristics, and treatment of paediatric generalised joint hypermobility (GJH) and joint hypermobility syndrome (JHS).Method. A narrative review was performed regarding diagnostics and clinical characteristics. Effectiveness of treatment was evaluated by systematic review. Searches of Medline and Central were performed and included nonsymptomatic and symptomatic forms of GJH (JHS, collagen diseases).Results. In the last decade, scientific research has accumulated on all domains of the ICF. GJH/JHS can be considered as a clinical entity, which can have serious effects during all stages of life. However research regarding the pathological mechanism has resulted in new potential opportunities for treatment. When regarding the effectiveness of current treatments, the search identified 1318 studies, from which three were included (JHS:n=2, Osteogenesis Imperfecta:n=1). According to the best evidence synthesis, there was strong evidence that enhancing physical fitness is an effective treatment for children with JHS. However this was based on only two studies.Conclusion. Based on the sparsely available knowledge on intervention studies, future longitudinal studies should focus on the effect of physical activity, fitness, and joint stabilisation. In JHS and chronic pain, the effectiveness of a multidisciplinary approach should be investigated.
Characteristics and Scenarios Projection of Climate Change on the Tibetan Plateau
Authors: Hao Zhenchun , Ju Qin , Jiang Weijuan , Zhu Changjun
Published: July 2013

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents twenty‐two global climate models (GCMs). In this paper, we evaluate the ability of 22 GCMs to reproduce temperature and precipitation over the Tibetan Plateau by comparing with ground observations for 1961~1900. The results suggest that all the GCMs underestimate surface air temperature and most models overestimate precipitation in most regions on the Tibetan Plateau. Only a few models (each 5 models for precipitation and temperature) appear roughly consistent with the observations in annual temperature and precipitation variations. Comparatively, GFCM21 and CGMR are able to better reproduce the observed annual temperature and precipitation variability over the Tibetan Plateau. Although the scenarios predicted by the GCMs vary greatly, all the models predict consistently increasing trends in temperature and precipitation in most regions in the Tibetan Plateau in the next 90 years. The results suggest that the temperature and precipitation will both increase in all three periods under different scenarios, with scenario A1 increasing the most and scenario A1B increasing the least.
Antiangiogenic Activity and Pharmacogenomics of Medicinal Plants from Traditional Korean Medicine
Authors: Seo Ean-Jeong , Kuete Victor , Kadioglu Onat , Krusche Benjamin , Schröder Sven , Greten Henry Johannes , Arend Joachim , Lee Ik-Soo , Efferth Thomas
Published: July 2013

Aim. In the present study, we investigated the antiangiogenic properties of 59 plants used in traditional Korean medicine. Selected phytochemicals were investigated in more detail for their modes of action.Methods. A modified chicken-chorioallantoic-membrane (CAM) assay using quail eggs was applied to test for antiangiogenic effects of plant extracts. A molecular dockingin silicoapproached the binding of plant constituents to the vascular endothelial growth factor receptors 1 and 2 (VEGFR1, VEGFR2). Microarray-based mRNA expression profiling was employed to correlate the 50% inhibition concentrations (IC50) of a panel of 60 NCI cell lines to these phytochemicals.Results. Extracts fromAcer monoleaves,Reynoutria sachalniensisfruits,Cinnamomum japonicumstems,Eurya japonicaleaves,Adenophora racemosawhole plant,Caryopteris incanaleaves-stems, andSchisandra chinensisstems inhibited angiogenesis more than 50% in quail eggs. Selected phytochemicals from Korean plants were analyzed in more detail using microarray-based mRNA expression profiles and molecular docking to VEGFR1 and VEGFR2. These results indicate multifactorial modes of action of these natural products.Conclusion. The antiangiogenic activity of plants used in traditional Korean medicine implicates their possible application for diseases where inhibition of blood vessel formation is desired, for example, cancer, macular degeneration, diabetic retinopathy and others.
Study and Determination of As, Cr, and Pb in Amaranth Seeds
Authors: Aguilar Elba Graciela , Cantarelli Miguel Angel , Marchevsky Eduardo Jorge , Escudero Nora Lilian , Camiña José Manuel
Published: July 2013

The concentration of As, Cr, and Pb toxic elements was determined in three species of amaranth seeds: A. hypochondriacus, A. cruentus, and A. dubius. The determinations were carried out by inductively coupled plasma optical atomic spectroscopy (ICP‐OES). The result shows that Cr and As were found in minor concentrations than allowed by the World Health Organization (WHO; 120 and 4 mg kg−1 resp.); As (mg kg−1): A. dubius (0.76) A. cruentus (<0.50) and A. hypochondriacus (<0.50); Cr (mg kg−1): A. dubius (8.19) A. cruentus (1.15) and A. hypochondriacus (1.20). However, the concentration of Pb was high: A. dubius (19.04) A. cruentus (30.20) and A. hypochondriacus (35.56) more than the maximum of WHO (10 mg kg−1). To avoid systematic error, recovery and validation studies were performed: recovery test: 102.3%; validation (by standard addition): 96.0–103.1%. Due to the fact that amaranth had been proposed as new food due to its nutraceutical properties, the high concentration of Pb found in this study indicates that Pb should be evaluated in these amaranth species to avoid the intake of toxic element by human beings.