bluuebunny/crossref_metadata_2025 huggingface dataset:
Plk1‐dependent microtubule dynamics promotes androgen receptor signaling in prostate cancer
Authors: Hou Xianzeng , Li Zhiguo , Huang Weize , Li Jiejie , Staiger Christopher , Kuang Shihuan , Ratliff Tim , Liu Xiaoqi
Published: May 2013

BACKGROUND

The androgen receptor (AR) signaling continues to be essential in castrate‐resistant prostate cancer (CRPC). Taxel‐based chemotherapy is the current standard treatment for CRPC patients. Unfortunately, almost all patients eventually develop resistance toward this chemotherapy. Significantly, it was recently found that the anti‐tumor effect of paclitaxel in CRPC is due to its inhibition of AR activity via its inhibition of microtubule dynamics. Polo‐like kinase 1 (Plk1), a critical regulator in many cell cycle events, is elevated in prostate cancer (PCa) and linked to tumor grades. Of note, we have previously shown that Plk1 phosphorylates CLIP‐170 and p150Glued, two important regulators of microtubule dynamics.

METHODS

We compared paclitaxel‐mediated phenotypes (inhibition of the AR signaling, decrease of microtubule dynamics and cell death) of PCa cells expressing different forms of CLIP‐170 and p150Glued with different Plk1 phosphorylation states.

RESULTS

We show that Plk1 phosphorylation of CLIP‐170 and p150Glued affects cellular responses to paclitaxel. Expression of Plk1‐unphosphorylatable mutants of CLIP‐170 and p150Glued results in increased paclitaxel‐induced apoptosis, increased protein degradation of the AR, and decreased nuclear accumulation of the AR in response to androgen in prostate cancer cells. Finally, we show that cells expressing unphosphorylatable mutants of CLIP‐170 have defective microtubule dynamics, thus providing a new mechanism to understand how Plk1‐associated kinase activity promotes constitutive activation of AR signaling in CRPC.

CONCLUSIONS

Our data suggest that a combination of inhibition of Plk1 and paclitaxel might be a novel avenue for treatment of CRPC. Prostate 73:1352–1363. © 2013 Wiley Periodicals, Inc.
Comparison Between the Efficacy of Ginger and Sumatriptan in the Ablative Treatment of the Common Migraine
Authors: Maghbooli Mehdi , Golipour Farhad , Moghimi Esfandabadi Alireza , Yousefi Mehran
Published: May 2013

Frequency and torment caused by migraines direct patients toward a variety of remedies. Few studies to date have proposed ginger derivates for migraine relief. This study aims to evaluate the efficacy of ginger in the ablation of common migraine attack in comparison to sumatriptan therapy. In this double‐blinded randomized clinical trial, 100 patients who had acute migraine without aura were randomly allocated to receive either ginger powder or sumatriptan. Time of headache onset, its severity, time interval from headache beginning to taking drug and patient self‐estimation about response for five subsequent migraine attacks were recorded by patients. Patients, satisfaction from treatment efficacy and their willingness to continue it was also evaluated after 1 month following intervention. Two hours after using either drug, mean headaches severity decreased significantly. Efficacy of ginger powder and sumatriptan was similar. Clinical adverse effects of ginger powder were less than sumatriptan. Patients' satisfaction and willingness to continue did not differ. The effectiveness of ginger powder in the treatment of common migraine attacks is statistically comparable to sumatriptan. Ginger also poses a better side effect profile than sumatriptan. Copyright © 2013 John Wiley & Sons, Ltd.
A trust model based on semantic distance for pervasive environments
Authors: Chen Zhi‐Gang , Wang Jiang‐Tao , Deng Xiao‐Heng
Published: May 2013

To cope with the challenges existing in pervasive environments, based on the characteristics of pervasive environments, a semantic distance‐based trust model is proposed in this paper. The semantic distance between entities and between trust categories is borrowed to calculate trustworthiness more precisely. In the model, the behavior trust and capability trust are distinguished and evaluated separately; on the basis of the trust evaluations, all entities in pervasive environments make independent decisions that can maximize their own profit with the trust model. The simulation experiment results proved the effectiveness of the model in improving the interaction success ratio and efficiency between entities under pervasive environments. Copyright © 2013 John Wiley & Sons, Ltd.
How to record ductus venosus blood velocity in the second half of pregnancy
Authors: Martins W. P. , Kiserud T.
Published: May 2013

How To…

Practical advice on imaging‐based techniques and investigations with accompanying slides online
Influence of the acid content of (acrylate processing aid)‐based lanthanum(III)‐neutralized ionomer on the thermal degradation and fusion behavior of rigid poly(vinyl chloride)
Authors: Zhu Xiaonan , Song Yihu , Zheng Qiang
Published: May 2013

Acrylate processing aid (ACR)‐based La(III)‐neutralized ionomers with different acid and La(III) ion contents were synthesized. Increasing lanthanum content in the ionomers led to an increment in the size of the ionic aggregate. Increasing acid content resulted in an increasing glass transition temperature ascribed to ion aggregation and to the occurrence of dense hydrogen bonding. The influences of acid and ion contents of the ionomers on the fusion and thermal stabilization behaviors of poly(vinyl chloride) (PVC) were investigated. The results revealed that at the low acid content of 0.25 mmol/g of hydrolyzed ACR, the stabilization efficiency of the ionomers enhanced with an increase of ion content before the appearance of clusters. At acid contents of 1.80 and 2.90 mmol/g, the ionomers exhibited poor ability to stabilize PVC during processing. The fusion‐promoting efficiency of the ionomers showed the same trend as the stabilization efficiency. Cluster formation and increasing acid content were also disadvantageous for ionomer use in promoting PVC fusion. J. VINYL ADDIT. TECHNOL., 19:86–93, 2013. © 2013 Society of Plastics Engineers
Use of nitric oxide nanoparticulate platform for the treatment of skin and soft tissue infections
Authors: Kutner Allison J. , Friedman Adam J.
Published: May 2013

The incidence of skin and soft tissue infections (SSTI) due to multi‐drug resistant pathogens is increasing. The concomitant increase in antibiotic use along with the ease with which organisms develop mechanisms of resistance have together become a medical crisis, underscoring the importance of developing innovative and effective antimicrobial strategies. Nitric oxide (NO) is an endogenously produced molecule with many physiologic functions, including broad spectrum antimicrobial activity and immunomodulatory properties. The risk of resistance to NO is minimized because NO has multiple mechanisms of antimicrobial action. NO's clinical utility has been limited largely because it is highly reactive and lacks appropriate vehicles for storage and delivery. To harness NO's antimicrobial potential, a variety exogenous NO delivery platforms have been developed and evaluated, yet limitations preclude their use in the clinical setting. Nanotechnology represents a paradigm through which these limitations can be overcome, allowing for the encapsulation, controlled release, and focused delivery of NO for the treatment of SSTI. WIREs Nanomed Nanobiotechnol 2013. doi: 10.1002/wnan.1230

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Fatty acid oxidation: systems analysis and applications
Authors: Cintolesi Angela , Rodríguez‐Moyá María , Gonzalez Ramon
Published: May 2013

Fatty acids (FAs) are essential components of cellular structure and energy‐generating routes in living organisms. They exist in a variety of chemical configurations and functionalities and are catabolized by different oxidative routes, according to their structure. α‐ and ω‐Oxidation are minor routes that occur only in eukaryotes, while β‐oxidation is the major degradation route in eukaroytes and prokaryotes. These pathways have been characterized and engineered from different perspectives for industrial and biomedical applications. The severity of FA oxidation disorders in humans initially guided the study of FA metabolism at a molecular‐level. On the other hand, recent advances in metabolic engineering and systems biology have powered the study of FA biosynthetic and catabolic routes in microorganisms at a systems‐level. Several studies have proposed these pathways as platforms for the production of fuels and chemicals from biorenewable sources. The lower complexity of microbial systems has allowed a more comprehensive study of FA metabolism and has opened opportunities for a wider range of applications. Still, there is a need for techniques that facilitate the translation of high‐throughput data from microorganisms to more complex eukaryotic systems in order to aid the development of diagnostic and treatment strategies for FA oxidation disorders. In addition, further systems biology analyses on human systems could also provide valuable insights on oxidation disorders. This article presents a comparison of the three main FA oxidative routes, systems biology analyses that have been used to study FA metabolism, and engineering efforts performed on microbial systems. WIREs Syst Biol Med 2013, 5:575–585. doi: 10.1002/wsbm.1226

This article is categorized under:

Biological Mechanisms > Metabolism

Physiology > Physiology of Model Organisms
Impact of Preoperative Breast MRI on Surgical Decision Making and Clinical Outcomes: A Systematic Review
Authors: Parsyan Armen , Alqahtani Awadh , Mesurolle Benoit , Meterissian Sarkis
Published: May 2013

Background

Preoperative magnetic resonance imaging (MRI) is increasingly used in the workup of breast cancer patients and could lead to changes in surgical management. It is unclear how the information gained from MRI studies affects surgical decision making and influences clinical outcomes. These issues are addressed in this review.

Methods

PubMed database searches were performed to retrieve and analyze respective original research and review articles on preoperative MRI in the evaluation of breast cancer patients.

Results

Preoperative MRI is a highly sensitive but nonspecific method that leads to changes in surgical management with increased numbers of more extended surgical interventions. It appears that a relatively large proportion of MRI‐driven changes in surgical management result in overtreatment without conclusively proven beneficial effects on such clinical outcomes as decrease in reoperation rates or improved patient survival.

Conclusions

Thus, routine use of supplementary preoperative breast MRI should be discouraged until compelling evidence of its effectiveness is available.
Assessment of β-carotene content, cell physiology and morphology of the yellow yeast Rhodotorula glutinis mutant 400A15 using flow cytometry
Authors: Cutzu Raffaela , Clemente Ana , Reis Alberto , Nobre Beatriz , Mannazzu Ilaria , Roseiro José , Lopes da Silva Teresa
Published: May 2013

Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and granularity in Rhodotorula glutinis mutant 400A15 grown under different oxygen transfer coefficients (k  L  a) and carbon to nitrogen ratios (C/N). A Doehlert distribution was used in order to select the best conditions that induced the highest carotenoids production. The highest β-carotene content (0.79 mg g−1 DCW) at the lowest k  L  a and C/N (5 × 10−3 s−1 and 11.3 respectively). Under these conditions, the biomass concentration attained 18.60 g L−1. The highest ratio of cells with permeabilised membranes (2.6 %), and the highest cell size and granularity were also obtained under these conditions. It was observed that C/N showed a stronger influence than the k  L  a on the measured cell parameters.
The Compositional and Institutional Sources of Union Dissolution for Married and Unmarried Parents in the United States
Authors: Tach Laura , Edin Kathryn
Published: May 2013

Unmarried parents have less stable unions than married parents, but there is considerable debate over the sources of this instability. Unmarried parents may be more likely than married parents to end their unions because of compositional differences, such as more disadvantaged personal and relationship characteristics, or because they lack the normative and institutional supports of marriage, thus rendering their relationships more sensitive to disadvantage. In this article, we evaluate these two sources of union instability among married, cohabiting, and dating parents following the birth of a shared child, using five waves of longitudinal data from the Fragile Families and Child Wellbeing Study. Using discrete-time event history models, we find that demographic, economic, and relationship differences explain more than two-thirds of the increased risk of dissolution for unmarried parents relative to married parents. We also find that differential responses to economic or relationship disadvantage do not explain why unmarried parents are more likely to end their unions than married parents.
The Effects of Portal Website Attitude and E-Services on Branding of E-Stores
Authors: Chen Hsiu-Li , Mathews Shane
Published: May 2013

Purpose

Increasingly the company websites, along with the intermediary websites such as portal sites have become an integral component of the firms brand strategy. This study emphasises the importance of website service elements within portal sites and the impact on e-retailer brand attitudes and brand identity in an ever more competitive digital market-space.

Design/methodology/approach

The research employs structural equation modeling technique to capture the relationship among website attitude, e-service quality, brand attitude and brand identity.

Findings

The results from the study indicate consumer attitude perceptions toward portal website and e-service elements combine to increase brand attitude and also brand identity for e-retailers.

Originality/value

Although there has been a plethora of studies evaluating corporate websites and branding interactions there is limited comprehension of the impact of intermediary portal sites. Moreover, the literature is limited in validating the link between e-services with brand attitude and brand identity within a portal website context. This study develops a framework that highlights the important influence of e-services within portal websites and the impact on the firm's brand.
Disease‐causing mutations in KLHL3 impair its effect on WNK4 degradation
Authors: Wu Guojin , Peng Ji-Bin
Published: May 2013

Mutations in with‐no‐lysine (K) kinase 4 (WNK4) and a ubiquitin E3 ligase complex component kelch‐like 3 (KLHL3) both cause pseudohypoaldosteronism II (PHAII), a hereditary form of hypertension. We determined whether WNK4 or its effector is regulated by KLHL3 in Xenopus oocytes. KLHL3 inhibited the positive effect of WNK4 on Na+–Cl− cotransporter (NCC) by decreasing WNK4 protein abundance without decreasing that of NCC and the downstream kinase OSR1 directly. Ubiquitination and degradation of WNK4 were induced by KLHL3. The effect of KLHL3 on WNK4 degradation was blocked by a dominant negative form of cullin 3. All five PHAII mutations of KLHL3 tested disrupted the regulation on WNK4. We conclude that KLHL3 is a substrate adaptor for WNK4 in a ubiquitin E3 ligase complex.
Comparison of 2 minimally invasive routes for hysterectomy of large uteri
Authors: Smorgick Noam , Dalton Vanessa K. , Patzkowsky Kristin E. , Hoffman Mark R. , Advincula Arnold P. , As‐Sanie Sawsan
Published: May 2013

Objective

To compare the perioperative outcomes associated with 2 minimally invasive surgical routes for the hysterectomy of large fibroid uteri.

Methods

Retrospective review of 84 women undergoing hysterectomy via minilaparotomy (n = 54) or robot‐assisted laparoscopy (n = 30) for uteri weighing at least 500 g. Outcome measures included hemorrhage (blood loss of 500 mL or more) and postoperative length of stay.

Results

Unadjusted mean blood loss (560.2 ± 507.4 mL versus 165.0 ± 257.5 mL, P < 0.001), rate of hemorrhage (40.7% versus 6.7%, P = 0.001, odds ratio 6.1 [95% confidence interval 1.5–24.2]), and rate of blood transfusion (14.8% versus 0%, P = 0.03) were all higher with minilaparotomy than with robot‐assisted surgery, while the median postoperative stay was significantly shorter with robotic surgery (2 [range 1–4] days versus 1 [range 0–7] days, P < 0.01). After adjusting for differences in uterine weight using a multivariate linear regression analysis, the mean blood loss and the rate of hemorrhage were no longer significantly different between the 2 groups.

Conclusion

The minilaparotomy approach may be used to remove very large uteri and does not require specialized and expensive equipment, or advanced endoscopic training. The robotic approach, when feasible, allows for early postoperative discharge.
An explicit algebraic Reynolds-stress and scalar-flux model for stably stratified flows
Authors: Lazeroms W. M. J. , Brethouwer G. , Wallin S. , Johansson A. V.
Published: May 2013

This work describes the derivation of an algebraic model for the Reynolds stresses and turbulent heat flux in stably stratified turbulent flows, which are mutually coupled for this type of flow. For general two-dimensional mean flows, we present a correct way of expressing the Reynolds-stress anisotropy and the (normalized) turbulent heat flux as tensorial combinations of the mean strain rate, the mean rotation rate, the mean temperature gradient and gravity. A system of linear equations is derived for the coefficients in these expansions, which can easily be solved with computer algebra software for a specific choice of the model constants. The general model is simplified in the case of parallel mean shear flows where the temperature gradient is aligned with gravity. For this case, fully explicit and coupled expressions for the Reynolds-stress tensor and heat-flux vector are given. A self-consistent derivation of this model would, however, require finding a root of a polynomial equation of sixth-order, for which no simple analytical expression exists. Therefore, the nonlinear part of the algebraic equations is modelled through an approximation that is close to the consistent formulation. By using the framework of a$K\text{{\ndash}} \omega $model (where$K$is turbulent kinetic energy and$\omega $an inverse time scale) and, where needed, near-wall corrections, the model is applied to homogeneous shear flow and turbulent channel flow, both with stable stratification. For the case of homogeneous shear flow, the model predicts a critical Richardson number of 0.25 above which the turbulent kinetic energy decays to zero. The channel-flow results agree well with DNS data. Furthermore, the model is shown to be robust and approximately self-consistent. It also fulfils the requirements of realizability.
Some insights for the prediction of near-wall turbulence
Authors: Karimpour Farid , Venayagamoorthy Subhas K.
Published: May 2013

In this paper, we revisit the eddy viscosity formulation to highlight a number of important issues that have direct implications for the prediction of near-wall turbulence. For steady wall-bounded turbulent flows, we make the equilibrium assumption between rates of production ($P$) and dissipation ($\epsilon $) of turbulent kinetic energy ($k$) in the near-wall region to propose that the eddy viscosity should be given by${\nu }_{t} \approx \epsilon / {S}^{2} $, where$S$is the mean shear rate. We then argue that the appropriate velocity scale is given by$\mathop{(S{T}_{L} )}\nolimits ^{- 1/ 2} {k}^{1/ 2} $where${T}_{L} = k/ \epsilon $is the turbulence (decay) time scale. The difference between this velocity scale and the commonly assumed velocity scale of${k}^{1/ 2} $is subtle but the consequences are significant for near-wall effects. We then extend our discussion to show that the fundamental length and time scales that capture the near-wall behaviour in wall-bounded shear flows are the shear mixing length scale${L}_{S} = \mathop{(\epsilon / {S}^{3} )}\nolimits ^{1/ 2} $and the mean shear time scale$1/ S$, respectively. With these appropriate length and time scales (or equivalently velocity and time scales), the eddy viscosity can be rewritten in the familiar form of the$k$–$\epsilon $model as${\nu }_{t} = \mathop{(1/ S{T}_{L} )}\nolimits ^{2} {k}^{2} / \epsilon $. We use the direct numerical simulation (DNS) data of turbulent channel flow of Hoyas & Jiménez (Phys. Fluids, vol. 18, 2006, 011702) and the turbulent boundary layer flow of Jiménezet al. (J. Fluid Mech.vol. 657, 2010, pp. 335–360) to perform‘a priori’tests to check the validity of the revised eddy viscosity formulation. The comparisons with the exact computations from the DNS data are remarkable and highlight how well the equilibrium assumption holds in the near-wall region. These findings could prove to be useful in near-wall modelling of turbulent flows.
Solution of the quasi-one-dimensional linearized Euler equations using flow invariants and the Magnus expansion
Authors: Duran Ignacio , Moreau Stephane
Published: May 2013

The acoustic and entropy transfer functions of quasi-one-dimensional nozzles are studied analytically for both subsonic and choked flows with and without shock waves. The present analytical study extends both the compact nozzle solution obtained by Marble & Candel (J. Sound Vib., vol. 55, 1977, pp. 225–243) and the effective nozzle length proposed by Stow, Dowling & Hynes (J. Fluid Mech., vol. 467, 2002, pp. 215–239) and by Goh & Morgans (J. Sound Vib., vol. 330, 2011, pp. 5184–5198) to non-zero frequencies for both modulus and phase through an asymptotic expansion of the linearized Euler equations. It also extends the piecewise-linear approximation of the velocity profile in the nozzle proposed by Moase, Brear & Manzie (J. Fluid Mech., vol. 585, 2007, pp. 281–304) to any arbitrary profile or equivalently any nozzle geometry. The equations are written as a function of three variables, namely the dimensionless mass, total temperature and entropy fluctuations, yielding a first-order linear system of differential equations with varying coefficients, which is solved using the Magnus expansion. The solution shows that both the modulus and the phase of the transfer functions of the nozzle have a strong dependence on the frequency. This holds for both choked flows and subsonic converging–diverging nozzles. The method is used to compare two different nozzle geometries with the same inlet and outlet Mach numbers, showing that, even if the compact solution predicts no differences between the transfer functions of the two nozzles, significant differences are found at non-zero frequencies. A parametric study is finally performed to calculate the indirect to direct noise ratio for a model combustor, showing that this ratio decreases at higher frequencies.
Hydroelastic response of floating elastic discs to regular waves. Part 1. Wave basin experiments
Authors: Montiel F. , Bonnefoy F. , Ferrant P. , Bennetts L. G. , Squire V. A. , Marsault P.
Published: May 2013

A series of wave basin experiments is reported that investigates the flexural response of one or two floating thin elastic discs to monochromatic waves. The work is motivated by numerical model validation. Innovative techniques are used to ensure the experimental configuration is consistent with the model. This demands linear motions, time-harmonic conditions, homogeneity of the plate and the restriction of horizontal motions of the disc or discs. An optical remote sensing device is employed to record the deflection of the discs accurately. Tests involving a single disc and two discs are conducted for a range of disc thicknesses, incident wave steepnesses, frequencies and, in the case of two discs, geometrical arrangements. A data processing technique is used to decompose the raw data into its spectral harmonics and filter the higher-order components. Pointwise comparisons of the linear first-order component of the experimental deflection with numerical predictions are presented. Satisfying agreement is found, although the model consistently over predicts the deflection. Disc–disc interactions are observed in the two-disc tests. A brief discussion of the shortcomings of the pointwise analysis, with associated possible sources of discrepancy, provides a link to the study reported in Part 2 (Montiel et al. J. Fluid Mech., vol. 723, 2013, pp. 629–652).
Hydroelastic response of floating elastic discs to regular waves. Part 2. Modal analysis
Authors: Montiel F. , Bennetts L. G. , Squire V. A. , Bonnefoy F. , Ferrant P.
Published: May 2013

Validation of a linear numerical model of wave interactions with floating compliant discs is sought using data obtained from the wave basin experiments reported in Part 1 (Montielet al. J. Fluid Mech., vol. 723, 2013, pp. 604–628). Comparisons are made for both single-disc tests and the two-disc tests in which wave interactions between discs are observed. The deflection of the disc or discs is separated into the natural modes of vibrationin vacuo. The decomposition allows the rigid-body motions and flexural motions to be analysed separately. Rigid-body motions are accurately replicated by the numerical model but, although passable agreement is found, the amplitudes of flexural modes are consistently overestimated. Extensions of the numerical model are used to discount the experimental configuration as a source of the discrepancies. An enhanced viscoelastic model for the discs is also proposed, which results in improved model/data agreement for the flexural motions but cannot account for all of the disagreement.
On the problem of large-scale magnetic field generation in rotating compressible convection
Authors: Favier B. , Bushby P. J.
Published: May 2013

Mean-field dynamo theory suggests that turbulent convection in a rotating layer of electrically conducting fluid produces a significant$\alpha $-effect, which is one of the key ingredients in any mean-field dynamo model. Provided that this$\alpha $-effect operates more efficiently than (turbulent) magnetic diffusion, such a system should be capable of sustaining a large-scale dynamo. However, in the Boussinesq model that was considered by Cattaneo & Hughes (J. Fluid Mech., vol. 553, 2006, pp. 401–418) the dynamo produced small-scale, intermittent magnetic fields with no significant large-scale component. In this paper, we consider the compressible analogue of the rotating convective layer that was considered by Cattaneo & Hughes (2006). Varying the horizontal scale of the computational domain, we investigate the dependence of the dynamo upon the rotation rate. Our simulations indicate that these turbulent compressible flows can drive a small-scale dynamo but, even when the layer is rotating very rapidly (with a mid-layer Taylor number of$Ta= 1{0}^{8} $), we find no evidence for the generation of a significant large-scale component of the magnetic field on a dynamical time scale. Like Cattaneo & Hughes (2006), we measure a negligible (time-averaged)$\alpha $-effect when a uniform horizontal magnetic field is imposed across the computational domain. Although the total horizontal magnetic flux is a conserved quantity in these simulations, the (depth-dependent) horizontally averaged magnetic field always exhibits strong fluctuations. If these fluctuations are artificially suppressed within the code, we measure a significant mean electromotive force that is comparable to that found in related calculations in which the$\alpha $-effect is measured using the test-field method, even though we observe no large-scale dynamo action.
Near-wall turbulent fluctuations in the absence of wide outer motions
Authors: Hwang Yongyun
Published: May 2013

Numerical experiments that remove turbulent motions wider than ${ \lambda }_{z}^{+ } \simeq 100$ are carried out up to ${\mathit{Re}}_{\tau } = 660$ in a turbulent channel. The artificial removal of the wide outer turbulence is conducted with spanwise minimal computational domains and an explicit filter that effectively removes spanwise uniform eddies. The mean velocity profile of the remaining motions shows very good agreement with that of the full simulation below ${y}^{+ } \simeq 40$, and the near-wall peaks of the streamwise velocity fluctuation scale very well in the inner units and remain almost constant at all the Reynolds numbers considered. The self-sustaining motions narrower than ${ \lambda }_{z}^{+ } \simeq 100$ generate smaller turbulent skin friction than full turbulent motions, and their contribution to turbulent skin friction gradually decays with the Reynolds number. This finding suggests that the role of the removed outer structures becomes increasingly important with the Reynolds number; thus one should aim to control the large scales for turbulent drag reduction at high Reynolds numbers. In the near-wall region, the streamwise and spanwise velocity fluctuations of the motions of ${ \lambda }_{z}^{+ } \leq 100$ reveal significant lack of energy at long streamwise lengths compared to those of the full simulation. In contrast, the losses of the wall-normal velocity and the Reynolds stress are not as large as those of these two variables. This implies that the streamwise and spanwise velocities of the removed motions penetrate deep into the near-wall region, while the wall-normal velocity and the Reynolds stress do not.
Large-eddy simulation of passive scalar dispersion in an urban-like canopy
Authors: Philips D. A. , Rossi R. , Iaccarino G.
Published: May 2013

Results from large-eddy simulations of short-range dispersion of a passive scalar from a point source release in an urban-like canopy are presented. The computational domain is that of a variable height array of buildings immersed in a pressure-driven, turbulent flow with a roughness Reynolds number ${\mathit{Re}}_{\tau } = 433$. A comparative study of several cases shows the changes in plume behaviour for different mean flow directions and source locations. The analysis of the results focuses on utilizing the high-fidelity datasets to examine the three-dimensional flow field and scalar plume structure. The detailed solution of the flow and scalar fields within the canopy allows for a direct assessment of the impact of local features of the building array geometry. The staggered, skewed and aligned arrangements of the buildings with respect to the oncoming flow were shown to affect plume development. Additional post-processing quantified this development through parameters fundamental to reduced-order Gaussian dispersion models. The parameters include measures of concentration decay with distance from the source as well as plume trajectory and spread. The horizontal plume trajectory and width were found to be more sensitive to source location variations, and hence local geometric features, than vertical plume parameters.
Rotating horizontal convection
Authors: Barkan Roy , Winters Kraig B. , Llewellyn Smith Stefan G.
Published: May 2013

‘Horizontal convection’ (HC) is the generic name for the flow resulting from a buoyancy variation imposed along a horizontal boundary of a fluid. We study the effects of rotation on three-dimensional HC numerically in two stages: first, when baroclinic instability is suppressed and, second, when it ensues and baroclinic eddies are formed. We concentrate on changes to the thickness of the near-surface boundary layer, the stratification at depth, the overturning circulation and the flow energetics during each of these stages. Our results show that, for moderate flux Rayleigh numbers ($O(1{0}^{11} )$), rapid rotation greatly alters the steady-state solution of HC. When the flow is constrained to be uniform in the transverse direction, rapidly rotating solutions do not support a boundary layer, exhibit weaker overturning circulation and greater stratification at all depths. In this case, diffusion is the dominant mechanism for lateral buoyancy flux and the consequent buildup of available potential energy leads to baroclinically unstable solutions. When these rapidly rotating flows are perturbed, baroclinic instability develops and baroclinic eddies dominate both the lateral and vertical buoyancy fluxes. The resulting statistically steady solution supports a boundary layer, larger values of deep stratification and multiple overturning cells compared with non-rotating HC. A transformed Eulerian-mean approach shows that the residual circulation is dominated by the quasi-geostrophic eddy streamfunction and that the eddy buoyancy flux has a non-negligible interior diabatic component. The kinetic and available potential energies are greater than in the non-rotating case and the mixing efficiency drops from${\sim }0. 7$to${\sim }0. 17$. The eddies play an important role in the formation of the thermal boundary layer and, together with the negatively buoyant plume, help establish deep stratification. These baroclinically active solutions have characteristics of geostrophic turbulence.
Wall turbulence without walls
Authors: Mizuno Yoshinori , Jiménez Javier
Published: May 2013

We perform direct numerical simulations of turbulent channels whose inner layer is replaced by an off-wall boundary condition synthesized from a rescaled interior flow plane. The boundary condition is applied within the logarithmic layer, and mimics the linear dependence of the length scales of the velocity fluctuations with respect to the distance to the wall. The logarithmic profile of the mean streamwise velocity is recovered, but only if the virtual wall is shifted to a position different from the location assumed by the boundary condition. In those shifted coordinates, most flow properties are within 5–10 % of full simulations, including the Kármán constant, the fluctuation intensities, the energy budgets and the velocity spectra and correlations. On the other hand, buffer-layer structures do not form, including the near-wall energy maximum, and the velocity fluctuation profiles are logarithmic, strongly suggesting that the logarithmic layer is essentially independent of the near-wall dynamics. The same agreement holds when the technique is applied to large-eddy simulations. The different errors are analysed, especially the reasons for the shifted origin, and remedies are proposed. It is also shown that the length rescaling is required for a stationary logarithmic-like layer. Otherwise, the flow evolves into a state resembling uniformly sheared turbulence.
Elasto-capillary coalescence of multiple parallel sheets
Authors: Gat A. D. , Gharib M.
Published: May 2013

We analyse two-dimensional clamped parallel elastic sheets which are partially immersed in liquid as a model for elasto-capillary coalescence. In the existing literature this problem is studied via minimal energy analysis of capillary and elastic energies of the post-coalescence state, yielding the maximal stable post-coalescence bundle size. Utilizing modal stability analysis and asymptotic analysis, we studied the stability of the configuration before the coalescence occurred. Our analysis revealed previously unreported relations between viscous forces, body forces, and the instability yielding the coalescence, thus undermining a common assumption that coalescence will occur as long as it will not create a bundle larger than the maximal stable post-coalesced size. A mathematical description of the process creating the hierarchical coalescence structure was obtained and yielded that the mean number of sheets per coalesced region is limited to the subset ${2}^{N} $ where $N$ is the set of natural numbers. Our theoretical results were illustrated by experiments and good agreement with the theoretical predictions was observed.
Peristaltic Flow of a Non-Newtonian Fluid in an Asymmetric Channel with Convective Boundary Conditions
Authors: Hayat T. , Yasmin Humaira , Alhuthali Mohammed S. , Kutbi Marwan A.
Published: May 2013

This article addresses peristaltic flow of third order fluid in an asymmetric channel. Channel walls are subjected to the convective boundary conditions. The channel asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitudes and phase. Long wavelength approximation and perturbation method give the series solutions for the stream function, temperature and longitudinal pressure gradient. Analysis has been further carried out for pressure rise per wavelength through numerical integration. Several graphs of physical interest are displayed and discussed.
Postprandial lipid responses to standard carbohydrates used to determine glycaemic index values
Authors: Vega-López Sonia , Ausman Lynne M. , Matthan Nirupa R. , Lichtenstein Alice H.
Published: May 2013

Prior studies assessing the metabolic effects of different types of carbohydrates have focused on their glycaemic response. However, the response of postprandial cardiometabolic risk indicators has not been considered in these studies. The present study assessed postprandial lipid responses to two forms of carbohydrates used as reference foods for glycaemic index determinations, white bread (50 g available carbohydrate) and glucose (50 g), under controlled conditions and with intra-individual replicate determinations. A total of twenty adults (20–70 years) underwent two cycles of challenges with each pair of reference foods (four challenges/person), administered in a random order on separate days under standard conditions. Serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, TAG and NEFA), glucose and insulin were monitored for 5 h post-ingestion. Oral glucose resulted in greater glycaemic and insulinaemic responses than white bread for the first 90 min and a greater subsequent decline after 120 min (P =0·0001). The initial decline in serum NEFA concentrations was greater after the oral glucose than after the white bread challenge, as was the rebound after 150 min (P =0·001). Nevertheless, the type of carbohydrate had no significant effect on postprandial total cholesterol, LDL-cholesterol and HDL-cholesterol concentrations. Following an initial modest rise in TAG concentrations in response to both challenges, the values dropped below the fasting values for oral glucose but not for the white bread challenge. These data suggest that the type of carbohydrate used to determine the glycaemic index, bread or glucose, has little or modest effects on postprandial plasma cholesterol concentrations. Differences in TAG and NEFA concentrations over the 5 h time period were modest, and their clinical relevance is unclear.
Effects of long-term administration of saturated andn-3 fatty acid-rich diets on lipid utilisation and oxidative stress in rat liver and muscle tissues
Authors: Feillet-Coudray Christine , Aoun Manar , Fouret Gilles , Bonafos Béatrice , Ramos Jeanne , Casas François , Cristol Jean Paul , Coudray Charles
Published: May 2013

The incidence of metabolic syndrome components including obesity, lipid deregulation, insulin resistance (IR) and non-alcoholic fatty liver disease is increasing rapidly in wealthy societies. The present study was designed to determine the effect of different nutritional lipid patterns (quantity and quality) on lipid utilisation and oxidative stress in the liver and muscle of rats in an integrated fashion. A total of forty-eight Wistar male rats were fed for 12 weeks with a mixed, lard or fish-oil diet, containing either 50 or 300 g lipid/kg. Rats developed liver steatosis associated with moderate liver injury when fed the 30 % lipid diets, in spite of the absence of overt obesity or IR, except when fed the lard 30 % lipid diet. The intake of the 30 % lipid diets decreased hepatic lipogenesis and mitochondriogenesis and increased lipid peroxidation and protein oxidation. Surprisingly, muscle lipid content was not modified whatever the administered diet. The intake of the 30 % lipid diets increased the muscle protein expression of fatty acid (FA) translocase/cluster of differentiation 36 (FAT/CD36), PPARγ co-activator 1α (PGC-1α) and muscle carnitine palmitoyltransferase 1 (m-CPT1), reflecting increased FA transport in the muscle associated with increased oxidative metabolism. The lard 30 % lipid diet led to IR without modifying the muscle lipid content. The fish-oil 30 % lipid diet failed to prevent the development of hepatic steatosis and made the tissues more prone to oxidation. Overall, the present study suggests that the FA composition of muscle is more important than lipid accumulation itself in the modulation of insulin sensitivity, and indicates that precaution should be taken when advising an unphysiologically high (pharmacological) supplementation with long-chainn-3 PUFA.
Grape juice concentrate protects reproductive parameters of male rats against cadmium-induced damage: a chronic assay
Authors: Pires Vanessa Cardoso , Gollücke Andréa Pittelli Boiago , Ribeiro Daniel Araki , Lungato Lisandro , D'Almeida Vânia , Aguiar Odair
Published: May 2013

The aim of the present study was to investigate the effects of long-term grape juice concentrate (GJC) consumption, in two dosages, on the reproductive parameters of cadmium-exposed male rats. The effects of the concentrate on body mass gain, plasma testosterone levels, reproductive organ weights, daily sperm production, sperm morphology, testis histopathological and histomorphometrical parameters, and testicular antioxidant markers were investigated. Wistar rats (n54) were distributed into six groups: CdCl2; cadmium and grape juice I (1·18 g/kg per d); cadmium and grape juice II (2·36 g/kg per d); grape juice I (1·18 g/kg per d); grape juice II (2·36 g/kg per d); control. A single dose of CdCl2(1·2 mg/kg body weight (BW)) was injected intraperitoneally and the grape juice was administered orally for 56 d. The results indicated that cadmium changed all reproductive and antioxidant parameters. At dosage I (1·18 g/kg BW), GJC consumption did not show the effects against cadmium-induced damages. In contrast, at dosage II (2·36 g/kg BW), the GJC improved the gonadosomatic index (P= 0·003), serum testosterone levels (P= 0·001), the relative weight of epididymis (P= 0·013) and ventral prostate (P= 0·052), the percentage of normal sperm (P= 0·001), and histopathological and histomorphometrical parameters. In addition, at this dosage, normalisation of the enzymatic activity of superoxide dismutase (P= 0·001) and of testicular levels of glutathione (P= 0·03) were observed. The parameters of the non-exposed rats did not depict significant alterations. In conclusion, the product was able to act as a protector of reproductive function against cadmium-induced damage. Such a property was expressed in a dose-dependent manner as the more effective dose was dosage II. The GJC acted possibly by antioxidant mechanisms.
In utero foetal remains of the Cretaceous ichthyosaurian Platypterygius: ontogenetic implications for character state efficacy
Authors: KEAR BENJAMIN P. , ZAMMIT MARIA
Published: May 2013

Ichthyosaurians provide some of the most famous examples of ‘live birth’ in the amniote fossil record based on spectacular complete skeletons of gravid females. Such remains facilitate direct comparisons between adult and foetal life stages, and thus have significant impact on phylogenetic hypotheses that require discrete character states to be ontogenetically uncoupled. This is especially true for Cretaceous ichthyosaurian taxa, the majority of which have been established using single specimens of assumed osteological maturity. Our assessment of in utero ichthyosaurian remains from the late Albian of Australia was therefore aimed at testing ontogenetic stability amongst key traits defining the most ubiquitous Cretaceous taxon: Platypterygius. Surprisingly, almost all of the salient features were identifiable in our sample of undoubtedly immature individuals. Indeed, only the proportions of the sclerotic ring, relative ossification and fusion of various basicranial elements, development of the axial skeleton, prominence of the deltopectoral crest and dorsal trochanter, and formation (but seemingly not number) of distal articular facets on the humerus were found to vary from larger-bodied members of the same species (P. australis). Ontogenetic continuity amongst the majority of other phylogenetically pertinent skeletal structures advocates their application for cladistic analyses, and suggests that many classic characters used to differentiate Platypterygius remain diagnostic irrespective of growth stage.
Effects of the comminution rate and microbial contamination of particles in the rumen on accuracy ofin situestimates of digestion of protein and amino acids of dehydrated sugar beet pulp
Authors: GONZÁLEZ J. , ARROYO J. M. , GUEVARA-GONZÁLEZ J. A. , MOUBI R. , PIQUER O. , MOYA V. J.
Published: May 2013

Effects of the correction of microbial contamination (using15N techniques) and of considering the comminution rate (kc) of particles in the rumen on effective estimates of the ruminally undegraded (RU) fraction and its intestinal effective digestibility (IED) were examined in a sample of dehydrated sugar beet pulp (DBP) generating composite samples (from rumen-incubated residues) representative of the chemical composition of RU. Tested fractions were dry matter (DM), organic matter (OM, tested only for RU), crude protein (CP) and amino acids (AA). The study was performed on three rumen and duodenum cannulated wethers fed with a 2 : 1 (fresh weight basis) chopped oat hay-to-concentrate diet supplied at 40 g DM/kg BW0·75in six equal meals per day. The DBP showed sigmoid degradation kinetics: the fractional degradation rate increased by 5·8 times as time (h) increased from 0 to∞. Thekcrate (measured in the diet concentrate) represented 5·74% of the total rumen retention time of particles. As a result, the RU of DM was over-evaluated by 6·53% whenkcwas not considered. Microbial contamination of RU was high as in DM as in CP. Therefore, the overestimation of RU of DM was increased to 12·2% when this contamination was not corrected. The lack of this correction also led to large over-evaluations of RU and IED of CP and AA. As a result, the overestimation of the intestinal digested fraction was 40·9% for CP and 45·0% for total analysed AA. This overestimation varied largely among AA (from 18·9 to 88·7%). Corrected proportions of RU and IED were also variable among AA. Hypotheses on the causes of this variability are given. Resultant changes in the AA profile of the intestinal digested protein had some negative impact on the supply of essential AA and cysteine without affecting lysine. This problem is limited because the microbial protein synthesized from DBP fermentation in the rumen is largely predominant in the AA supply to the host.