bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Nanostructures in Anomalous Thermal Conductivity of Nanofluids
Authors: Murshed S. M. Sohel , Nieto de Castro C. A.
Published: December 2014

Nanofluids have stimulated immense research interest due to their superior thermophysical properties, heat transfer features and potential applications in numerous important fields. Role of nanostructures in heat transfer mechanisms and thermal properties particularly thermal conductivity of nanofluids has been presented and relevant studies are critically reviewed in this study. Research demonstrated that nanofluids exhibit anomalous thermal conductivity (generally higher than their base fluids) which increases with the loading of nanoparticles. Despite of some findings on positive impact of agglomeration or clustering of nanoparticles on thermal conductivity, contrary findings (negative) and argumentations are still widely accepted in the nanofluids research community. Literature results showed that while cluster size increases with concentration of nanoparticles, thermal conductivity of nanofluids decreases with increasing the cluster size. However, it is not yet well-understood how to control the morphology of the clusters of nanoparticles and how do they play role in changing the thermal properties of nanofluids. Furthermore, studies revealed that the primary shape or structures of nanomaterials also influence the properties of nanofluids. Nanofluids containing nanotubes of large aspect ratio exhibit superior thermal conductivity compared to nanofluids having nanoparticles of any other shapes. Nanorods (cylinder)-laden nanofluids showed slightly higher thermal conductivity than that of nanosphere-based nanofluids. Nevertheless, the structures of agglomerated or individual nanoparticles and their nano- or molecular-level activities in the host fluids are mainly responsible for the anomalous thermal conductivity of nanofluids.
Molecular Dynamics Simulations of Benchmark Geometries Representing a Flow Through Porous Media
Authors: Uth Marc-Florian , Asmuth Henrik , Windt Christian , Herwig Heinz
Published: December 2014

Fluid Dynamics Simulations are often based on continuum assumptions that, for micro- or nano-flows, are extended by models that take into account special phenomena (e. g. wall slip) that occour in these dimensions. On the nano-scale not only the near wall layers show peculiarities. Especially for liquids the bulk flow deviates from smooth profiles and thus strongly differs from continuum theory. So far mainly the flow in straight channels has been investigated with Molecular Dynamics Simulations. In real porous media such perfectly flat channels do not appear. Thus, to analyze the applicability of the continuum assumption for the simulation of fluid flow on the pore-scale the type of geometries that are evaluated has to be extended. Therefore in this paper we present the results of Molecular Dynamics Simulations of a liquid in a Couette flow, the flow through a straight channel, a bend and through an array of cylinders. We present the results for varying wall-fluid potentials, shear rates, and temperatures and compare the results to the validated data from a finite volume solution of the Navier-Stokes-Equations for the same geometries. As a result we show the difficulties due to complex geometries for the simulation with Molecular Dynamics. Also the boundary conditions for Molecular Dynamics Simulations, like the thermostat or the wall model are discussed. We show that for some parameter sets, a critical behaviour can be observed for the more complex geometries. Such results are evaluated to show the differences between MD and FVM simulations. It turns out however, that the limits of the continuum assumptions are very different for different geometries. In complex geometries the minimum characteristic size can be much smaller than in straight channels. Hence the scope of continuum methods for the simulation of fluid flow through porous media on the pore scale is larger than expected.
Motion and Deformation of a Water Droplet Under the Influence of an Electric Field
Authors: DeProw Kyle , Darabi Jeff
Published: December 2014

Due to its molecular polarity, a water droplet suspended in a dielectric medium experiences a force under the influence of an electric field. However, unlike a charged rigid particle, a water droplet undergoes a significant deformation due to its liquid state. Thus, the dynamic behavior of the water droplet cannot be fully analyzed without accounting for the interaction between the electric and fluid fields. In an effort to broaden our understanding of this phenomenon, a parallel plate electrode system was constructed inside a glass chamber. A water droplet was suspended in the glass chamber filled with insulated oil. After applying a high voltage across the plates, the droplet motion was recorded with a camera and analyzed using an image processing program. The effects of several parameters including, droplet size, droplet conductivity, and initial droplet position were investigated. Results obtained from this investigation help gain a better understanding of the droplet deformation and breakup mechanisms spanning several fields, some of which include oil-water separation, electrocoalescence, and electrospraying.
Numerical Simulation of Flow Pattern of Boiling Heat Transfer in Mini/Micro Channel Using VOF Method
Authors: Gamit Jigar C. , Channiwala Salim A.
Published: December 2014

In order to better understand the flow physics and boiling phenomenon, numerical simulation of the flow patterns developed in the flow boiling has been carried out and validated with the published experimental results. Simulations were carried out for R-134a as a working fluid with 1.75 mm circular channel and heated length of 600 mm. VOF method has been used to capture the liquid-vapour interface. Numerical simulations were in good agreement with the experimental results of flow patterns for lower values of heat and mass fluxes. But some discrepancies were observed at medium and higher values of heat and mass fluxes.
Parametric Studies of Single-Phase Multi-Layer Heat Sinks Using a Porous Media Approach: Effects of Spatially-Varying Porosity and Total Porosity
Authors: Podhiny John J. , Ortega Alfonso
Published: December 2014

Prior analyses and experiments have demonstrated that varying or scaling the number of fluid channels in each layer of a stacked multi-layer heat sink yields distinct advantages over traditional single-layer designs which use channels with high aspect ratios. Specifically, a design which implements scaling in order to vary the porosity (or equivalently, the number of channels) from one layer to the next allows a given thermal performance to be realized at a lower pressure drop than the corresponding non-scaled design. In previous work, the authors have used volume-averaged non-equilibrium porous media heat transfer theory to analyze a range of heat sinks of this type, including those with discrete or step-wise porosity variation (in earlier efforts) and continuous porosity variation (in more recent efforts). The authors have used discrete variation to model stacked mini-channel multi-later heat exchangers, and continuous variation as a more general investigative tool for this class of heat sinks. The continuous variation approach can also be used as a design tool for heat sink envelopes that use scaled micro- or nano-channels or engineered porous media with spatially varying porosity or pore diameter.

This paper reports on the results of a parametric study of water-cooled copper heat sinks which employ 0.50 mm × 0.50 mm square channels in a range of porosity scaling profiles that yield and total integrated porosities of 0.10 to 0.95. The investigation identifies the highest and lowest performing designs based upon temperatures on the heated surface, and analyzes their performance characteristics in terms of the spatial distributions of solid and fluid temperature distributions, thermal resistance components and ratios, and conductive and convective heat flows. In general, the results imply the existence of an optimum level and distribution of porosity and confirm the potential benefits of spatial variation of porosity.
Convective Heat Transfer of Unchoked and Choked Gas Flow in Micro-Tubes
Authors: Hong Chungpyo , Asako Yutaka
Published: December 2014

Heat transfer characteristics of unchoked and choked gas flows in micro-tubes with constant wall temperature were numerically investigated both laminar and turbulent flow cases. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian (ALE) method. The Lam-Bremhorst Low-Reynolds number turbulence model was used for turbulent flow. The compressible momentum and energy equations with the assumption of the ideal gas were solved. The computational domain should be extended to the downstream region of the hemisphere from micro-tube outlet. The back pressure was given to the outside of the downstream region. The stagnation temperature is fixed at 300K and the computations were done for the wall temperature which ranges from 305K to 350K. The tube diameter ranges from 50 to 250 μm and tube aspect ratio is 200. The stagnation pressure is chosen in such a way that the flow at micro-tube exit is enough to be fully under-expanded. By increasing the stagnation pressure, the internal flow in the micro-tube is choked and the flow at the micro-tube outlet is under-expanded. Although the velocity remains constant, the mass flow rate (Reynolds number) increases. The results in a wide range of Reynolds number and Mach number were obtained. The bulk temperature based on the static temperature and the total temperature are compared with those of the incompressible flow. A correlation for the prediction of the heat transfer rate of the unchoked and choked gas flow in micro-tubes is proposed.
Numerical Investigation of Irrigant Penetration Into Dentinal Microtubules
Authors: Motie Shirazi Mohsen , Abouali Omid , Emdad Homayoon , Nabavizade Mohammad Reza , Mirhadi Hossein , Ahmadi Goodarz
Published: December 2014

Root canal irrigation is an important procedure in endodontic treatment. After mechanical preparation of root canal, NaOCl, which is the most common antibacterial irrigant, is inserted by special needles. This work helps to remove bacteria and debris and dissolves the organic tissues in the root canal. In the vicinity of the main root canal, there are a large number of microchannels attached to its wall named “dentinal tubules”. The success of irragation depends on the penetration of irrigant in these tubules, which results in killing the bacteria and preventing complexities after root canal therapy.

There is rather limited earlier research on modeling of dentinal tubules. Nevertheless, it has been shown that the flow rate, insertion depth and needle types affect the flow pattern in the root canal. The concentration difference between inserted irrigant and the liquid filling the tubules is the main driving force for penetration. Diffusion of irrigant, however, is a time dependent process and should be analyzed as an unsteady problem.

In prior studies, the geometry was considered as cylinders with a constant diameter of 2.5μm and the effect of tapering was neglected. In reality the diameter varies from about 2.5μm near the pulp to about 1.5μm at the distance of 1 mm from the pulp.

In the present study, a more detailed and exact model of dentinal tubules geometry was considered. The computational fluid dynamics (CFD) is used for the modeling of flow and diffusion of irrigant as a function of time. The unsteady and 3D continuity and Navier-Stokes equations as well as a scalar transport equation are solved and the flow field and the concentration of antibacterial irrigant were evaluated. The simulation results were compared to the earlier works. It was shown that the use of the correct detailed geometry of tubules led to noticeable differences compared to those found for the idealized model.
Experimental Characterization of Stabilized Suspensions Caused by Formation of Nanoparticle Halos
Authors: Keramati Hadi , Zabetian Mohammad , Saidi Mohammad Hassan , Mozafari Ali Asghar
Published: December 2014

Suspension flow has an important role in various applications such as paint, material and pharmaceutical industries. Settling is considered as a resisting phenomenon in the processes dealing with suspensions. Using nanoparticles as an additive to micro-particulates has been studied in limited studies.

This work presents an experimental investigation to assess the effectiveness of nanoparticles in reduction of suspension settling. Microscopic imaging and transmission measurement were used to analyze the stability factors in a container. Transmission analysis revealed that presence of nanoparticles in the suspension, decreased the sedimentation rate. Microscopy showed that the settling rate decreased after adding nanoparticles. This is attributed to the repulsive forces between microparticles caused by the halos of nanoparticle. Highly charged nanoparticles segregate to region near negligibly charged microspheres because of their repulsive Coulombic interactions. Therefore, microparticles exhibit an effective charge in presence of nanoparticles.

Obtained results indicate that the nanoparticles with appropriate volume fraction can stabilize suspension of microparticles and can successfully minimize the settling rate. Proposed technique can be also implemented in other applications such as heat pipes and heat transfer devices.
The Effect of Temperature Dependent Electrical Conductivity on the MHD Natural Convection of Al2O3–Water Nanofluid in a Rectangular Enclosure
Authors: Asadian Ali Mohammad , Abouali Omid , Yaghoubi Mahmoud , Ahmadi Goodarz
Published: December 2014

The present paper is concerned with the study of flow and heat transfer characteristics in the steady state free convective flow of Al2O3-waternanofluids in a square enclosure in the presence of magnetic field. Attention is given to the temperature variation of the electrical conductivity and its effect on the electromagnetic force induced by the motion of the nanofluid. A new experimental correlation recently presented in the literature was used for this aim. In all the earlier studies in this area the electrical conductivity variation of nanofluid with temperature was neglected. The fluid viscosity and thermal conductivity are assumed to vary as a function of temperature and this variation is modeled using the available experimental correlations. The governing differential equations are solved numerically using finite element method. The features of fluid flow and heat transfer characteristics are analyzed for various strengths of the magnetic field and different nanoparticle volume fractions. The results show that when the inclusion of the variation of the electrical conductivity with temperature in the numerical model noticeably affects the natural convection heat transfer in the studied rectangular cavity. The variations of Nusselt number for natural convection of Al2O3-water nanofluid with nanoparticle volume fractions are presented at various Rayleigh and Hartmann numbers.
On the Liquid/Liquid Slug Flow in a Micro-Capillary Reactor
Authors: Dittmar Ina , Ehrhard Peter
Published: December 2014

The hydrodynamics within a liquid/liquid slug flow in a micro-capillary reactor is characterized by complex vortex structures, both within the disperse and within the continuous phase. Usually, one of the phases exhibits good wetting of the wall, while the second phase exhibits poor wetting. This is why we expect a (continuous) thin film of the wetting phase along the wall. We compute this complex two-phase flow by means of a finite-volume method (FVM), whereas the interface is captured by a modified level-set method. Hence, from our numerical simulations we obtain the detailed topology of this two-phase flow, the position of the interface, as well as the thickness of the thin wall film of the continuous phase. With regard to the thickness of this wall film in liquid/liquid systems, very little information is available in literature. Of course, the hydrodynamics of this two-phase flow is the basis for any species transport computations within such micro-capillary reactors.

We discuss in detail the topology of this two-phase flow, as it develops for various parameters. Moreover, a careful comparison of experimental and theoretical findings on the wall film thickness is presented.
Transonic Wall-Slip Analysis for Expanding Micro Diffuser Flows for Cold Gas Propulsion Systems
Authors: Groll Rodion
Published: December 2014

The use of highly diluted and supersonic gas flow is in the scope of application of cold gas thrusters for space applications. Satellites and small spacecrafts are navigated to their orbital trajectory with these nozzles (Fig. 1). Inside these propulsion systems high density gradients are dominating the efficiency and the thrust steering behavior of the propulsion systems. In the present study a trans-sonic nozzle flow is computed by using a calibrated velocity slip model which depends on the Knudsen number. The Knudsen numbers are lower the Kn=1 at the nozzle neck of the propulsion system. The results are compared with simulation results of a uniform channel flow and computations of the corresponding no-slip approach. The differences in the supersonic region are following discussed.
Analysis of a Viscoelastic Fluid Flow in a Microchannel With Asymmetric Zeta Potentials Under a Combination of Electroosmotic and Magnetohydrodynamic Driven Forces
Authors: Escandón Juan P. , Bautista Oscar E. , Méndez Federico
Published: December 2014

In this paper an analytical solution to describe the velocity profiles and flow rate of combined electroosmotic and magnetohydrodynamic flows in a microchannel is obtained. A fully-developed flow is considered and the fluid obeys a constitutive relation based in a simplified Phan-Thien-Tanner model. Asymmetric boundary conditions with different zeta potentials at the walls are specified to provide a perturbation to the fluid flow. The effect of the dimensionless parameters on the flow field as viscoelastic parameter, the Hartmann number, the ratio of applied electric fields on the fluid field and the ratio of the wall zeta potentials is predicted. The analysis permits to establish the conditions for which the flow rate is increased respect to a purely electroosmotic flow, therefore, in the limit of small Hartmann numbers and low electrical conductivity in the buffer solution correspond to the range where the electric and magnetic effects can be used to move a charged solution in the flow control and sample handling in biomedical and chemical analysis. In addition, we determine the conditions that must be met to prevent the undesirable lateral electroosmotic flow, which is present in this kind of applications. Finally, the combined effect of asymmetric zeta potentials and electro-magnetic fields on viscoelastic fluid flows in microchannels is discussed as future application of mixed in microfluidics devices.
Geometric Optimisation of Conjugate Pentagonal Cooling Channels With Internal Heat Generation
Authors: Olakoyejo Olabode Thomas , Martins Lauber , Obayopo Surajudeen Olanrewaju , Meyer Josua Petrus
Published: December 2014

This paper presents a three-dimensional geometric optimisation of conjugate cooling channels in forced convection with internal heat generation within the solid. Pentagonal cooling channels configuration are considered. The main objective is to optimise the configuration in such a way that the peak temperature is minimised subject to the constraint of fixed global volume of solid material. The cooling fluid is driven through the channels by the pressure difference across the channel.

The elemental volume of the structure and hydraulic diameter of the cooling channel were considered as design variables. The shape of the channel is allowed to morph to determine the best configuration that gives the lowest thermal resistance. A gradient-based mathematic optimisation algorithm (Dynamic-Q) is applied in order to search for the best optimal geometric configuration that improves thermal performance by minimising thermal resistance for a wide range of dimensionless pressure difference. Results obtained show that there are unique optimal geometry for a given pressure difference. Also, the results show that the effects of dimensionless pressure drop on minimum thermal resistance and hydraulic diameter of the channel are consistent with those obtained in the open literature.
Numerical Investigation of Fiber Flocculation in the Air Flow of an Asymmetric Diffuser
Authors: Andric Jelena , Lindström Stefan B. , Sasic Srdjan , Nilsson Håkan
Published: December 2014

A particle-level rigid fiber model is used to study flocculation in an asymmetric planar diffuser with a turbulent Newtonian fluid flow, resembling one stage in dry-forming process of pulp mats. The fibers are modeled as chains of rigid cylindrical segments. The equations of motion incorporate hydrodynamic forces and torques from the interaction with the fluid, and the fiber inertia is taken into account. The flow is governed by the Reynolds-averaged Navier–Stokes equations with the standard k–ω turbulence model. A one-way coupling between the fibers and the flow is considered. A stochastic model is employed for the flow fluctuations to capture the fiber dispersion. The fibers are assumed to interact through short-range attractive forces, causing them to interlock as the fiber-fiber contacts occur during the flow. It is found that the formation of fiber flocs is driven by both the turbulence-induced dispersion and the gradient of the averaged flow field.
Fluid Flow Characteristics in Micro-Gas-Jets
Authors: Asako Yutaka
Published: December 2014

This paper reviews the current status of researches on a micro-gas-jet from a straight micro-tube. A series of experimental and numerical studies on a micro-gas-jet from a straight micro-tube have been conducted by our research group to reveal fluid flow characteristics of under-expanded gas flow at a micro-tube outlet. In this paper, the findings obtained by our recent studies will be introduced. This is, the numerically obtained Mach number at the outlet plane of a micro-tube, the displacement thickness of the boundary layer formed on the tube wall near the outlet are presented. The configuration of a micro-gas-jet and structure of the flow in the potential core are presented. And the Mach number of a micro-gas-jet obtained from the shockwave angle generated from a needle tip inserted in the micro-jet and the measured Pitot total pressure of a micro-gas-jet are also presented. Comparisons with numerical results are also presented.
Servicing in Sponsorship: A Best-Worst Scaling Empirical Analysis
Authors: O’Reilly Norm , Huybers Twan
Published: December 2014

As an accepted tool in the promotional mix of organizations, sponsorship and sport sponsorship have become everyday marketing practice, in which sponsors invest in sponsees in return for marketing value. The implementation, or fulfillment, as it is often called in practice, of a sponsorship involves three main activities: activation, evaluation and servicing. While the literature has investigated both activation and evaluation, work in the area of servicing is limited. Guided by a sponsorship-linked marketing lens, a longitudinal study of sponsorship organizations was undertaken followed by a best-worst scaling experiment. Longitudinal results inform us that sponsees are underservicing sponsors; however, the best-worst scaling experiment finds a reduced gap. Results illustrate that although gaps between importance and performance perceptions are relatively small for sponsors, sponsees and agencies, a mixed pattern of agreement and disagreement exists between each of the three respondent groups in relation to the specific importance and performance dimensions.
Fandom in the Workplace: Multi-Target Identification in Professional Team Sports
Authors: Swanson Steve , Kent Aubrey
Published: December 2014

Team identification has been researched extensively from the perspective of the consumer. The current study proposes that employees working in professional sport may also be fans of their respective teams, and provides insight on the role of team identification in the workplace environment. Over 1100 business operations employees from the top profession sports leagues in North America participated, and results indicate that dual targets of identification exist simultaneously in this setting. Strong support is provided for the discriminant validity between organizational and team identification. Beyond the more established effects of organizational identification, the results provide evidence that team identification independently predicts key outcomes such as commitment, satisfaction, and motivation. The results add to the literature by introducing the concept of a sports team as an additional target of identification in the organizational context.
Creating and Sustaining Workplace Cultures Supportive of LGBT Employees in College Athletics
Authors: Cunningham George B.
Published: December 2014

The purpose of this study was to understand (a) how participants conceptualized lesbian, gay, bisexual, and transgender (LGBT) inclusiveness in their athletic departments, (b) the antecedents of such workplace environments, and (c) the outcomes associated with inclusion. To do so, the author conducted a collective case study of two college athletic departments located in the U.S. Northeast. Data sources included individual interviews with coaches and administrators (n = 17), a reflexive journal, websites, university materials, and external publications. Participants described the athletic departments as characterized by community and cohesion, respect and inclusion, and success oriented. Various antecedents contributed to these workplace environments, including those at the individual level, leader behaviors, inclusive organizational policies, and macro-level influences. Finally, while some negative outcomes were identified, LGBT inclusion was predominantly associated with a host of positive outcomes for the employees, athletes, and organizations as a whole.
Effective use of mirtazapine for refractory pruritus associated with carcinoma en cuirasse
Authors: Lee Jonathan J , Girouard Sasha D , Carlberg Valerie M , Mostaghimi Arash
Published: December 2014

Pruritus is a debilitating symptom that can be associated with cutaneous involvement by an underlying malignancy. We report the case of a 68-year-old woman with a history of triple-negative breast cancer who presented with extensive, localised cutaneous metastasis complicated by incapacitating, treatment-refractory pruritus localised to the anatomic regions involved by her metastatic disease. Physical examination revealed an indurated, ecchymotic, ulcerated plaque circumferentially encasing her thorax. Histopathological examination revealed substantial dermal lymphatic involvement and dilation as well as dermal collagen infiltration by tumour cells and nodules. The clinical and pathological findings were consistent with a diagnosis ofcarcinoma en cuirasse. Mirtazapine, a noradrenergic antidepressant with antiserotonin and antihistamine activity, was started and led to rapid, sustained relief of the patient's pruritus. Mirtazapine may be a useful systemic agent for the palliative relief of pruritus associated with cutaneous infiltration by an underlying malignancy.
On the (2 + 1)-dimensional Dirac equation in a constant magnetic field with a minimal length uncertainty
Authors: Pedram P. , Amirfakhrian M. , Shababi H.
Published: December 2014

In this paper, we exactly solve the (2 + 1)-dimensional Dirac equation in a constant magnetic field in the presence of a minimal length. Using a proper ansatz for the wave function, we transform the Dirac Hamiltonian into two two-dimensional nonrelativistic harmonic oscillator and obtain the solutions without directly solving the corresponding differential equations which are presented by Menculini et al. [Phys. Rev. D 87 (2013) 065017]. We also show that Menculini et al. solution is a subset of the general solution which is related to the even quantum numbers.
CASE REPORT: COMBINATION OF ANTITHROMBOTICS AND THROMBOLYTICS TREATMENT IN A CAT WITH DISTAL AORTIC THROMBOEMBOLISM
Authors: Huang Wan-Wen , Jen Chih-Chueh , Lee Wei-Ming
Published: December 2014

A 14-year-old intact male Chinchilla cat was presented to Veterinary Teaching Hospital, Chung Hsing University due to a sudden weakness of the hind limbs. Coldness was found on both hind limbs. Pulseless on the right hind limb and a weak-pulsed on the left hind limb were revealed by physical examination. Thrombus was detected in aortic bifurcation by ultrasonography. After treating the patient with supportive care, antithrombotics (including Dalteparin sodium, clopidgrel) and thrombolytics (Streptokinase), the thrombus lysed on the next day. Being able to use the affected limbs in the following days, the cat was discharged on the 6th day, although Ischemia-reperfusion injury was still presented. It indicated that thrombolytics may be a choice that is beneficial to some cats with distal aortic thromboembolism.
Impaired cardiac energy metabolism in embryos lacking adrenergic stimulation
Authors: Baker Candice N. , Gidus Sarah A. , Price George F. , Peoples Jessica N. R. , Ebert Steven N.
Published: December 2014

As development proceeds from the embryonic to fetal stages, cardiac energy demands increase substantially, and oxidative phosphorylation of ADP to ATP in mitochondria becomes vital. Relatively little, however, is known about the signaling mechanisms regulating the transition from anaerobic to aerobic metabolism that occurs during the embryonic period. The main objective of this study was to test the hypothesis that adrenergic hormones provide critical stimulation of energy metabolism during embryonic/fetal development. We examined ATP and ADP concentrations in mouse embryos lacking adrenergic hormones due to targeted disruption of the essential dopamine β-hydroxylase ( Dbh) gene. Embryonic ATP concentrations decreased dramatically, whereas ADP concentrations rose such that the ATP/ADP ratio in the adrenergic-deficient group was nearly 50-fold less than that found in littermate controls by embryonic day 11.5. We also found that cardiac extracellular acidification and oxygen consumption rates were significantly decreased, and mitochondria were significantly larger and more branched in adrenergic-deficient hearts. Notably, however, the mitochondria were intact with well-formed cristae, and there was no significant difference observed in mitochondrial membrane potential. Maternal administration of the adrenergic receptor agonists isoproterenol or l-phenylephrine significantly ameliorated the decreases in ATP observed in Dbh−/−embryos, suggesting that α- and β-adrenergic receptors were effective modulators of ATP concentrations in mouse embryos in vivo. These data demonstrate that adrenergic hormones stimulate cardiac energy metabolism during a critical period of embryonic development.
Transcriptome profiling of brown adipose tissue during cold exposure reveals extensive regulation of glucose metabolism
Authors: Hao Qin , Yadav Rachita , Basse Astrid L. , Petersen Sidsel , Sonne Si B. , Rasmussen Simon , Zhu Qianhua , Lu Zhike , Wang Jun , Audouze Karine , Gupta Ramneek , Madsen Lise , Kristiansen Karsten , Hansen Jacob B.
Published: December 2014

We applied digital gene expression profiling to determine the transcriptome of brown and white adipose tissues (BAT and WAT, respectively) during cold exposure. Male C57BL/6J mice were exposed to cold for 2 or 4 days. A notable induction of genes related to glucose uptake, glycolysis, glycogen metabolism, and the pentose phosphate pathway was observed in BAT from cold-exposed animals. In addition, glycerol-3-phosphate dehydrogenase 1 expression was induced in BAT from cold-challenged mice, suggesting increased synthesis of glycerol from glucose. Similarly, expression of lactate dehydrogenases was induced by cold in BAT. Pyruvate dehydrogenase kinase 2 ( Pdk2) and Pdk4 were expressed at significantly higher levels in BAT than in WAT, and Pdk2 was induced in BAT by cold. Of notice, only a subset of the changes detected in BAT was observed in WAT. Based on changes in gene expression during cold exposure, we propose a model for the intermediary glucose metabolism in activated BAT: 1) fluxes through glycolysis and the pentose phosphate pathway are induced, the latter providing reducing equivalents for de novo fatty acid synthesis; 2) glycerol synthesis from glucose is increased, facilitating triacylglycerol synthesis/fatty acid re-esterification; 3) glycogen turnover and lactate production are increased; and 4) entry of glucose carbon into the tricarboxylic acid cycle is restricted by PDK2 and PDK4. In summary, our results demonstrate extensive and diverse gene expression changes related to glucose handling in activated BAT.
Phenotypic Characteristics of Nasal Mast Cells in a Mouse Model of Allergic Rhinitis
Authors: Li Pu , Cui Yeqing , Song Gongru , Wang Zhenlin , Zhang Qiuhang
Published: December 2014

Background: Mast cells (MCs) in the nasal respiratory mucosa (NRM) play a triggering role in the pathogenesis of allergic rhinitis (AR). Recent research evidence in mouse models of AR suggests an underlying MC-related allergic response in mouse nasal olfactory mucosa (NOM). Objective: We sought to investigate the phenotypic characteristics of nasal MCs in a mouse model of AR. Methods: By MC-specific staining and immunohistochemistry, we analyzed the subset, protease and IgE-binding phenotypes of nasal MCs in ovalbumin (OVA)-sensitized unchallenged and challenged mice. Results: In OVA-sensitized challenged mice, increased serum OVA-specific IgE levels (p < 0.001) and eosinophil infiltration confirmed AR induction. In addition to constitutive connective tissue MCs, mucosal MCs were induced in NRM and NOM of OVA-sensitized challenged mice. Connective tissue MCs and mucosal MCs in mouse NRM and NOM were positive for mouse MC protease-1, -4, -5, -6, -7 and carboxypeptidase-A3. In line with MCs in NRM, there were increased numbers (p = 0.019) and proportions (p = 0.027) of MCs with surface-bound IgE in NOM of OVA-sensitized challenged mice. Conclusion: In the setting of AR, MCs in mouse NOM exhibit the same subset, protease and IgE-binding phenotypes as MCs in mouse NRM.
Is Schizophrenia a Neurodegenerative Disease? Evidence from Age-Related Decline of Brain-Derived Neurotrophic Factor in the Brains of Schizophrenia Patients and Matched Nonpsychiatric Controls
Authors: Rao Jagadeesh , Chiappelli Joshua , Kochunov Peter , Regenold William T. , Rapoport Stanley I. , Hong L. Elliot
Published: December 2014

Background: Brain-derived neurotrophic factor (BDNF) protein levels decline in the brain during senescence and are also shown to be reduced in schizophrenia patients. BDNF is present in both the gray and white matters of the brain. It is unclear whether BDNF abnormalities in schizophrenia are specific to gray and/or white matter. Objective: We hypothesized that the age-related BDNF decline is abnormal and contributes to the reduced BDNF in schizophrenia. Methods: We tested this hypothesis by measuring BDNF protein levels in postmortem gray and white matter, using the prefrontal cortex (PFC) and the genu of the corpus callosum as regions of interests, from 20 schizophrenia patients and 20 matched nonpsychiatric controls. Samples were selected across the adult lifespan - from 20 to 80 years of age. Results: PFC gray matter BDNF protein levels were significantly lower in older age in both nonpsychiatric comparisons and patients, while BDNF in white matter did not decrease significantly with age in either group. PFC BDNF was linearly lower from 20 to 80 years of age in nonpsychiatric comparisons. In schizophrenia, the age effect was similarly linear in younger patients but a decline did not occur in older patients. Conclusion: PFC BDNF does not follow a normative linear age effect in schizophrenia patients as they grow older, which may represent a ‘floor effect' due to earlier decline or a survivor cohort of older patient donors who are less susceptible to a schizophrenia-related pathological aging process.
Promoter-Dependent Activity on Androgen Receptor N-Terminal Domain Mutations in Androgen Insensitivity Syndrome
Authors: Tadokoro-Cuccaro Rieko , Davies John , Mongan Nigel P. , Bunch Trevor , Brown Rosalind S. , Audi Laura , Watt Kate , McEwan Iain J. , Hughes Ieuan A.
Published: December 2014

Androgen receptor (AR) mutations are associated with androgen insensitivity syndrome (AIS). Missense mutations identified in the AR-N-terminal domain (AR-NTD) are rare, and clinical phenotypes are typically mild. We investigated 7 missense mutations and 2 insertion/deletions located in the AR-NTD. This study aimed to elucidate the pathogenic role of AR-NTD mutants in AIS and to use this knowledge to further define AR-NTD function. AR-NTD mutations (Q120E, A159T, G216R, N235K, G248V, L272F, and P380R) were introduced into AR-expression plasmids. Stably expressing cell lines were established for del57L and ins58L. Transactivation was measured using luciferase reporter constructs under the control of GRE and Pem promoters. Intrinsic fluorescence spectroscopy and partial proteolysis studies were performed for mutations which showed reduced activities by using a purified AR-AF1 protein. Pem-luciferase reporter activation was reduced for A159T, N235K, and G248V but not the GRE-luciferase reporter. Protein structure analysis detected no significant change in the AR-AF1 region for these mutations. Reduced cellular expression and transactivation activity were observed for ins58L. The mutations Q120E, G216R, L272F, P380R, and del57L showed small or no detectable changes in function. Thus, clinical and experimental analyses have identified novel AR-signalling defects associated with mutations in the structurally disordered AR-NTD domain in patients with AIS.
“On Slavery”
Authors: Grünstäudl Wolfgang
Published: December 2014

The saying ᾧ γάρ τις ἥττηται, τούτῳ δεδούλωται (“a man becomes the slave of him who overpowers him”) can be found—with minor variations—in five Christian texts from the first four centuries (2 Pet 2:19; Hippolytus, Comm. Dan. III,22.4; Origen, Hom. Exod. 12.4; Adamant. 58.1-2; and Ps.-Clem. Rec. V,12.4). The present paper discusses the presence of this saying (“On Slavery”) in such a diverse group of writings and argues that “On Slavery” seems to be a Herrenwort which was independently used by four authors of early Christianity, while Origen, Hom. Exod. 12.4 is most likely a quote of 2 Pet 2:19.
Heeft Het Theïsme Eigen Gronden? Alvin Plantinga Over de ‘Proper Basicality’ van Religieus Geloof
Authors: Glas Gerrit
Published: December 2014

The title of this article is ambiguous in the sense that it may direct the attention to either (a) theism as a system of beliefs of persons who are referring to particular facts that serve as external grounds for the foundation of theist beliefs (the foundationalist approach) or (b) to theism as a system of beliefs of persons who are convinced of theism’s truth on grounds that are intrinsic to their belief (the Pascalian approach). Traces of both conceptions of theism can be found in Alvin Plantinga’s thesis of the ‛proper basicality’ of religious belief, for instance in the distinction between evidence of the ‛on the basis of …’- type and evidence of the ‛inclination’- type. However, these two types of evidence do only lead to doxastic experience. In order to be warranted with respect to a particular knowledge claim, beliefs must be produced by noetic capacities that function properly, i.e. according to their design plan and in contexts that are appropriate to these capacities. This externalist epistemology exerts its greatest power in the criticism of the ‛evidentialist objection to belief in God’. However, it raises a number of objections with respect to its positive account of theism. When every community of thinkers creates its own relevant set of examples in order to establish criteria of proper basicality, does this not lead to skepticism? And, can doxastic experience not be honoured as a proper response to being called by divine discourse and, correspondingly, be seen as the relational foundation of theist belief?
Great Pumpkins, Externalisme en Religieuze Twijfel
Authors: Roeser Sabine
Published: December 2014

Alvin Plantinga verdedigt een externalistische kentheorie ten aanzien van religieus geloof. In dit artikel beargumenteer ik dat een internalistische benadering meer recht doet aan de manier waarop veel mensen hun relatie ten aanzien van geloven ervaren: geloven gaat vaak gepaard met twijfel, en iemand moet in zijn of haar (on)geloof vaak afwegingen maken tussen argumenten voor en tegen het bestaan van God. In Plantinga’s theorie wordt er aan het metafysische probleem of er al dan niet een God bestaat te weinig recht gedaan, waardoor er tevens te weinig ruimte wordt geboden voor wederzijds respect tussen gelovigen en niet gelovigen.
Hartstocht en Rede (III, SLOT)
Authors: van der Hoeven J.
Published: December 2014

Diverse omstandigheden hebben het schrijven en verschijnen van het in jaargang 62 (1997), nr. 2 aangekondigde slotartikel vertraagd. Ook toen al uitte ik het voornemen de vier denkers die in het tweede artikel besproken waren nog even te groeperen. Zo�n korte groepering lijkt nu, na meer dan twee jaar, des te meer wenselijk. De vier besproken filosofen waren allen, zij het op uiteenlopende wijze, op zoek naar een nieuwe bepaling van de verhoudingen, � niet alleen tussen �Leidenschaft�� en �Vernunft��, maar ook tussen �Leidenschaft�� als in-zet � meer actief � en als �passio��, in de zin van �lijden��.
Limonium poimenum (Plumbaginaceae), a new chasmophyte species from Sicily
Authors: ILARDI VINCENZO , Brullo Salvatore , CUSIMANO DARIO , GALDO GIANPIETRO GIUSSO DEL
Published: December 2014

Limonium poimenum is here proposed as a new species for Science. It is a very peculiar and extremely localized species, growing on a calcareous mountain of NW Sicily (southern Italy), where it grows on rupestrian places together with many other rare chasmophytic endemics. Iconography, morphological features, ecology and conservation status are provided, as well as a morphological comparison with L. todaroanum.
Microlejeunea subaphanes, a new synonym of Cheilolejeunea decursiva (Marchantiophyta, Lejeuneaceae) new to America
Authors: Shu Lei , Wei Yu-Mei , Cheng Xia-Fang , Zhu Rui-Liang
Published: December 2014

Recent molecular phylogenetic studies have confirmed that Microlejeunea (Spruce 1884: 286) Stephani (1888: 61) is a good genus which is closely related to Lejeunea Libert (1820: 372) (Dong et al. 2013; Wei 2013). Microlejeunea is distinguished from Lejeunea by the presence of ocelli in the leaf lobe, transverse section of the stem consisting of seven cortical cells and three medullary cells, and keel of the female bract usually winged (Wei & Zhu 2013). Although about 50 species are currently accepted in Microlejeunea, most of them are still poorly known. Microlejeunea subaphanes Herzog (1950: 70) is a very rare species known only from the type specimen collected in São Paulo, Brazil (Herzog 1950; Gradstein & Costa 2003), and its identity is not clear (Bischler et al. 1963). Our examination of its type specimen showed that M. subaphanes does not belong to Micrololejeunea because of the distal hyaline papilla of the leaf lobule, pycnolejeuneoid gynoecial innovation, keel of female bract not winged, transverse section of the stem consisting of 7−9 cortical cells and 4−5 medullary cells, and absence of ocelli in the leaf lobe (Fig. 1). Further critical study revealed that M. subaphanes is conspecific with Cheilolejeunea decursiva (Sande Lacoste 1855: 522) Schuster (1963: 112), which is widespread in tropical Africa and rare in Asia (Borneo, Java, Sri Lanka), Australia and Oceania (Fiji, Hawaii) (Zhu & Lai 2005).
“You Are Learning Well My Dear”
Authors: Bieda Kristen N. , Sela Hagit , Chazan Daniel
Published: December 2014

Against the backdrop of mentor teachers’ reasoning about practice, we seek to understand shifts in intern teachers’ reasoning about practice during a year in which they take their final methods course in the fall and then do intern teaching in the spring. The data we analyze consist of intern and mentor teacher study group discussions of repeated viewings of an animation representing mathematics classroom practice around the solving of linear equations. Our analysis utilizes Toulmin’s framework of argumentation and the construct of professional obligations from the practical rationality of mathematics teaching. The analysis suggests that, in reasoning about practice, in the fall, intern teachers emphasized teachers’ obligations to mathematics as a discipline and to students as individuals, but as they moved into teaching, their arguments about practice include greater attention to obligations to the institutional goals of schools and to their class as a whole.
Online Activities, Digital Media Literacy, and Networked Individualism of Korean Youth
Authors: Park Sora , Kim Eun-mee , Na Eun-Yeong
Published: December 2014

Networked individualism enables Internet users to connect and socialize via their loose and transient multiple networks, whereas digital media literacy is a precondition of effective Internet use. In this study, an attempt has been made to find the link between networked individualism, digital media literacy, and young people’s perception of their social capital. A nationally representative face-to-face survey was conducted with Korean adolescents in 2013. Networked individualism was higher in adolescents who frequently engaged in online activities and who demonstrated greater digital media literacy. Belonging to multiple, diverse networks and having many connections was positively correlated to adolescents’ online social capital. Findings indicate that online activities and skills influence the ways adolescents connect to others and perceive of their social connectedness.
Comparing the Two- and Three-Parameter Logistic Models via Likelihood Ratio Tests
Authors: Brown Christy , Templin Jonathan , Cohen Allan
Published: December 2014

Selection of an appropriate item response model is critical in the measurement of latent examinee ability. The one-, two-, and three-parameter logistic (1PL, 2PL, and 3PL) models are nested, and as such can be compared using likelihood ratio (LR) tests. The null hypothesis in the LR test for selection among the 2PL and 3PL models sets the guessing parameters to their lower bound of 0. This violates one of the assumptions of the LR test and renders the usual [Formula: see text] reference distribution inappropriate for the comparison. A review of the current literature revealed that this problem is not well understood in the educational measurement field. Ignoring this issue can lead to selection of an overly simplified model, with implications for the ability estimates. In this article, the use of the LR test for item response model selection is investigated, with the goal of providing practitioners with an appropriate method of selecting the most parsimonious model. The results of simulation studies indicate the nature of the problem, with inaccurate Type I error rates for cases where the inappropriate null distribution was used. An analysis of data from a statewide mathematics test showed differences pertinent to subsequent analyses.