bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrinsic laryngeal muscles are spared from degeneration in the dy3k/dy3k mouse model of congenital muscular dystrophy type 1A
Authors: Häger Mattias , Durbeej Madeleine
Published: December 2008

Deficiency of laminin α2 chain leads to a severe form of congenital muscular dystrophy (MDC1A). Here, we analyzed whether the intrinsic laryngeal muscles (ILM) are spared in the dy3K/dy3K mouse model of complete laminin α2 chain absence. No muscle degeneration was evident; expression of various laminin chains was similar to that of limb muscles, and sustained integrin α7B expression was noted in laminin α2 chain‐deficient ILM. We conclude that ILM are spared in MDC1A. Muscle Nerve 39: 91–94, 2009
Piecewise constant level set method for structural topology optimization
Authors: Wei Peng , Wang Michael Yu
Published: December 2008

In this paper, a piecewise constant level set (PCLS) method is implemented to solve a structural shape and topology optimization problem. In the classical level set method, the geometrical boundary of the structure under optimization is represented by the zero level set of a continuous level set function, e.g. the signed distance function. Instead, in the PCLS approach the boundary is described by discontinuities of PCLS functions. The PCLS method is related to the phase‐field methods, and the topology optimization problem is defined as a minimization problem with piecewise constant constraints, without the need of solving the Hamilton–Jacobi equation. The result is not moving the boundaries during the iterative procedure. Thus, it offers some advantages in treating geometries, eliminating the reinitialization and naturally nucleating holes when needed. In the paper, the PCLS method is implemented with the additive operator splitting numerical scheme, and several numerical and procedural issues of the implementation are discussed. Examples of 2D structural topology optimization problem of minimum compliance design are presented, illustrating the effectiveness of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd.
On the application of generalized integral transform technique to wind‐induced vibrations on overhead conductors
Authors: Matt Carlos Frederico Trotta
Published: December 2008

The aim of the present paper is to describe the application of the generalized integral transform technique (GITT) for the theoretical analysis of wind‐induced vibrations on overhead conductors. In the mathematical model adopted, the complicated helicoidal geometry of the conductor is simplified by treating it as a homogeneous taut string simple supported at both ends. Solving the governing partial differential equation through the GITT approach, one derives purely analytical or analytical–numerical solutions for the conductor transverse displacement as a function of both position and time. In order to highlight the potential and flexibility of the GITT approach to account for realistic features of the phenomenon, three particular cases of practical interest are analyzed in detail, for which benchmark results are provided: (i) the damped‐free vibrations of the conductor; (ii) the harmonic‐forced vibrations of the conductor without and with Stockbridge dampers; and (iii) the forced vibrations of the conductor under a non‐linear wind excitation. The current results may be combined with previous analytical predictions to compute the conductor amplitudes and bending strains at critical locations. Although this work is focused on a taut string model for the conductor, the approach described herein may be easily extendable to the beam model. Copyright © 2008 John Wiley & Sons, Ltd.
Using a signed distance function for the simulation of metal forming processes: Formulation of the contact condition and mesh adaptation. From a Lagrangian approach to an Eulerian approach
Authors: Bruchon J. , Digonnet H. , Coupez T.
Published: December 2008

This paper proposes to use the metric properties of the distance function between two bodies in contact (or gap function) in simulations involving contact problems. First, the normal vectors, which are involved in the formulation of the contact condition, are defined through the gradient of this distance function. This definition avoids to deal with the numerical penetration parameter, which is generally introduced otherwise. Furthermore, it allows the contact problem to be extended in a simple way to an Eulerian formulation. Second, this paper investigates two mesh adaptation strategies based on the properties of the distance function. The first strategy consists in building a size map according to the values of this function, in order to refine locally the mesh, and consequently to improve the description of the contact surface. The second strategy consists in adapting locally the mesh to the geometry of the contact surface. This anisotropic adaptation is performed by constructing a metric map that allows the mesh size to be imposed in the direction of the distance function gradient. A lot of elements are saved when compared with the isotropic case. Throughout this paper, many numerical simulations are presented in the context of the forging process: the deformable material is pressed between two rigid tools. Furthermore, the algorithm used to calculate the signed distance to a surface mesh is detailed in appendix of this paper. Copyright © 2008 John Wiley & Sons, Ltd.
Gender comparisons of perceived benefits of and barriers to physical activity in middle school youth
Authors: Robbins Lorraine B. , Sikorskii Alla , Hamel Lauren M. , Wu Tsu‐Yin , Wilbur JoEllen
Published: December 2008

Perceived benefits of and barriers to physical activity (PA) reported by 206 middle school boys and girls in a survey were compared. Only “take care of myself, stay in shape, and be healthier” emerged as a greater benefit for girls than boys. Among students not on a sports team, boys reported fewer barriers than girls. Among those selecting an active pursuit, boys perceived more barriers than girls. When controlling for sports team participation and perceived benefits and barriers, boys reported more minutes of vigorous PA than girls. As boys and girls reported relatively similar benefits of and barriers to PA, nurse counseling with both groups can focus on the same information. Effort is particularly needed to increase PA among girls. © 2008 Wiley Periodicals, Inc. Res Nurs Health 32:163–176, 2009
Single step synthesis of poly(3‐octylthiophene)/multi‐walled carbon nanotube composites and their characterizations
Authors: Kim Hee Jin , Koizhaiganova Raushan , Vasudevan T. , Sanjeeviraja C. , Lee Mu Sang
Published: December 2008

The transport properties of conducting polymers are known to be greatly influenced by the chemical unsaturation surrounding the polymer backbone, besides favorable conformation of the side chains present. Polymeric composites with multi‐walled carbon nanotubes (MWNT) can provide a good conductive path at relatively low carbon contents, as these have high aspect ratio, specific surfaces and are cost effective. Hence their use in various applications such as organic LED, solar cells and supercapacitors are very much anticipated. In this respect poly(3‐octylthiophene)/MWNT composites have been prepared by an “insitu” polymerization process in chloroform medium with FeCl3 oxidant at room temperature. The composites were characterized by Fourier Transfer Infrared spectroscopy (FT‐IR), Raman, work function and X‐ray diffraction (XRD) measurements. The results indicate only a weak π‐π interaction between the moieties, in the absence of a strong covalent bonding. The ultraviolet–visible (UV–Vis) measurements also support this view. The photoluminescence (PL) quenching indicates the effectiveness of the interface in the formation of the donor–acceptor type composite. The conductivity of the composites is followed by a four probe technique to understand the conduction mechanism. The Hall voltage measurement is followed to monitor carrier concentrations and mobilities. The impressive conductivity and mobility values encourage the utility of the composites as photovoltaic material. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of sulfonated aromatic poly(ether amide)s and their application to proton exchange membrane fuel cells
Authors: Jo Tae Soo , Ozawa Coreen H. , Eagar Bryce R. , Brownell Lacie V. , Han Daehyun , Bae Chulsung
Published: December 2008

A series of wholly aromatic sulfonated poly(ether amide)s (SPEAs) containing a sulfonic acid group on the dicarbonyl aromatic ring were prepared via a polycondensation reaction of sulfonated terephthalic acid (STA), terephthalic acid (TA), and aromatic diamine monomers. The degree of sulfonation was readily controlled by adjusting the monomer feed ratio of STA and TA in the polymerization process, and randomly sulfonated polymers with an ion exchange capacity (IEC) of 1.0–1.8 mequiv/g were prepared using this protocol. The chemical structures of randomly sulfonated polymers were characterized using NMR and FT‐IR spectroscopies. Gel permeation chromatography analysis of SPEAs indicated the formation of high‐molecular‐weight sulfonated polymer. Tough and flexible SPEA membranes were obtained from solution of N,N‐dimethylacetamide, and thermogravimetric analysis of these membranes showed a high degree of thermal stability. Compared with previously reported sulfonated aromatic polyamides, these new SPEAs showed a significantly lower water uptake of 10–30%. In proton conductivity measurements, ODA‐SPEA‐70 (IEC = 1.80 mequiv/g), which was obtained from polycondensation of 4,4′‐oxydianiline and 70 mol % STA, showed a comparable proton conductivity (105 mS/cm) to that of Nafion 117 at 80 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 485–496, 2009
ROMP‐NMP‐ATRP combination for the preparation of 3‐miktoarm star terpolymer via click chemistry
Authors: Gozgen Aziz , Dag Aydan , Durmaz Hakan , Sirkecioglu Okan , Hizal Gurkan , Tunca Umit
Published: December 2008

A combination of ring opening metathesis polymerization (ROMP) and click chemistry approach is first time utilized in the preparation of 3‐miktoarm star terpolymer. The bromide end‐functionality of monotelechelic poly(N‐butyl oxanorbornene imide) (PNBONI‐Br) is first transformed to azide and then reacted with polystyrene‐b‐poly(methyl methacrylate) copolymer with alkyne at the junction point (PS‐b‐PMMA‐alkyne) via click chemistry strategy, producing PS‐PMMA‐PNBONI 3‐miktoarm star terpolymer. PNBONI‐Br was prepared by ROMP of N‐butyl oxanorbornene imide (NBONI) 1 in the presence of (Z)‐but‐2‐ene‐1,4‐diyl bis(2‐bromopropanoate) 2 as terminating agent. PS‐b‐PMMA‐alkyne copolymer was prepared successively via nitroxide‐mediated radical polymerization (NMP) of St and atom transfer radical polymerization (ATRP) of MMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 497–504, 2009
Disperse red 1 end capped oligoesters. Synthesis by noncatalyzed ring opening oligomerization and structural characterization
Authors: Peptu Cristian , Harabagiu Valeria , Simionescu Bogdan C. , Adamus Grazyna , Kowalczuk Marek , Nunzi Jean‐Michel
Published: December 2008

The synthesis of novel azofunctional oligoesters through bulk ring opening of ε‐caprolactone and D,L‐lactide (LA) at 100 and 130 °C, respectively, mediated by N‐ethyl‐N‐(2‐hydroxyethyl)‐4‐(4‐nitrophenylazo)aniline (Disperse Red 1) (DR1) is described. The synthetic procedure allows “clean” products because no catalysts were used in the reaction. Moreover, DR1 moiety is showed for the first time to promote the ring opening of cyclic esters. The molecular structure of the obtained oligoesters was established by NMR spectroscopy, MALDI ToF MS and electrospray ionization mass spectrometry (ESI MS). ESI‐MS/MS fragmentation experiments were used to demonstrate the nature of the chain end groups (hydroxyl and DR1). Intermolecular transesterification reactions were proved by mass spectrometry studies at least in the case of LA oligomerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 534–547, 2009
Photoinduced unzipping depolymerization of poly(olefin sulfone)s possessing photobase generator and base amplifier
Authors: Sasaki Takeo , Yaguchi Hiroaki
Published: December 2008

The photoinduced depolymerization of poly(olefin sulfone)s was investigated. Poly(olefin sulfone)s possessing base‐amplifying groups were synthesized. A photobase‐generating compound was mixed with poly(olefin sulfone)s and irradiated with 254 nm UV light. The decomposition ratio was significantly enhanced in poly(olefin sulfone)s that possessed base‐amplifying groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 602–613, 2009
Novel well‐defined glycopolymers synthesized via the reversible addition fragmentation chain transfer process in aqueous media
Authors: Deng Zhicheng , Ahmed Marya , Narain Ravin
Published: December 2008

We describe here the direct synthesis of novel gluconamidoalkyl methacrylamides by reacting D‐gluconolactone with aminoalkyl methacrylamides. The glycomonomers were then successfully polymerized via the reversible addition‐fragmentation chain transfer process (RAFT) using 4‐cyanopentanoic acid dithiobenzoate (CTP) as chain transfer agent and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as the initiator in aqueous media. Well‐defined polymers were obtained as revealed by gel permeation chromatography. Diblock copolymers were then synthesized by the macro‐CTA approach. The cationic glycopolymers were subsequently used in the formation of nanostructures via the complexation with plasmid DNA. As noted by dynamic light scattering, monodisperse nanoparticles were obtained via the electrostatic interaction of the cationic glycopolymer with DNA. The sizes of the nanoparticles formed were found to be stable and independent of pH. In vitro cell viability studies of the glycopolymers were carried out using HELA cell lines. The RAFT synthesized glycopolymers and cationic glyco‐copolymers revealed to be nontoxic. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 614–627, 2009
Synthesis of the four‐arm star‐block copolymer [PVC‐b‐PBA‐CH(CH3)COOCH2]4C by SET‐DTLRP initiated from a tetrafunctional initiator
Authors: Percec Virgil , Sienkowska Monika J.
Published: December 2008

Pentaerythritol tetrakis(2‐iodopropionate) was used as a tetrafunctional initiator for the Na2S2O4 catalyzed SET‐DTLRP of n‐butyl acrylate in water at room temperature. The resulting tetrafunctional poly(n‐butyl acrylate) macroinitiator with Mn = 14,864 or Mn = 3627 per arm was used to initiate the SET‐DTLRP of vinyl chloride and provide the first examples of four‐arm star‐block copolymers [PVC‐b‐PBA‐CH(CH3)COOCH2]4C. The Mn of the PVC segment from each arm of the four‐arm star‐block copolymer varied between 353 and 33,622. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 628–634, 2009
Synthesis of α,ω‐di(iodo)PVC and of four‐arm star PVC with identical active chain ends by SET‐DTLRP of VC initiated with bifunctional and tetrafunctional initiators
Authors: Sienkowska Monika J. , Percec Virgil
Published: December 2008

Na2S2O4‐catalyzed single‐electron transfer – degenerative chain transfer‐mediated living radical polymerization (SET‐DTLRP) of VC initiated with the bifunctional initiators 1,2‐bis(iodopropionyloxy)ethane, dimethyl 2,5‐diiodohexanedioate, and bis(2‐methoxyethyl)‐2,5‐diiodohexanedioate as well as the tetrafunctional initiator pentaerythritol tetrakis(2‐iodopropionate) is reported. This SET‐DTLRP was performed in water at ambient temperature in the presence of polyvinyl alcohol and hydroxypropyl methylcellulose surfactants and provides methods for the synthesis of α,ω‐di(iodo)PVC with two identical active chain ends and of four‐arm star PVC with four identical active chain ends. These difunctional and tetrafunctional derivatives of PVC are also macroinitiators for the synthesis of ABA triblock copolymers and four‐arm star block copolymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 635–652, 2009
Strategic plan for pediatric respiratory diseases research: An NHLBI working group report
Authors: Abman Steve , Jobe Alan , Chernick Victor , Blaisdell Carol , Castro Mario , Ramirez Maria I. , Gern James E. , Cutting Garry , Redding Greg , Hagood James S. , Whitsett Jeffrey , Abman Steve , Raj J. Usha , Barst Robyn , Kato Gregory J. , Gozal David , Haddad Gabriel G. , Prabhakar Nanduri R. , Gauda Estelle , Martinez Fernando D. , Tepper Robert , Wood Robert E. , Accurso Frank , Teague W. Gerald , Venegas Jose , Cole F. Sessions , Wright Rosalind J.
Published: December 2008

The Division of Lung Diseases of the National Heart, Lung and Blood Institute (NHLBI) recently held a workshop to identify gaps in our understanding and treatment of childhood lung diseases and to define strategies to enhance translational research in this field. Leading experts with diverse experience in both laboratory and patient‐oriented research reviewed selected areas of pediatric lung diseases, including perinatal programming and epigenetic influences; mechanisms of lung injury, repair, and regeneration; pulmonary vascular disease (PVD); sleep and control of breathing; and the application of novel translational methods to enhance personalized medicine. This report summarizes the proceedings of this workshop and provides recommendations for emphasis on targeted areas for future investigation. The priority areas identified for research in pediatric pulmonary diseases included: (1) epigenetic and environmental influences on lung development that program pediatric lung diseases, (2) injury, regeneration, and repair in the developing lung, (3) PVD in children, (4) development and adaptation of ventilatory responses to postnatal life, (5) nonatopic wheezing: aberrant large airway development or injury? (6) strategies to improve assessment, diagnosis, and treatment of pediatric respiratory diseases, and (7) predictive and personalized medicine for children. Pediatr Pulmonol. 2009; 44:2–13. © 2008 Wiley‐Liss, Inc.
Simulating protein folding initiation sites using an alpha‐carbon‐only knowledge‐based force field
Authors: Buck Patrick M. , Bystroff Christopher
Published: December 2008

Protein folding is a hierarchical process where structure forms locally first, then globally. Some short sequence segments initiate folding through strong structural preferences that are independent of their three‐dimensional context in proteins. We have constructed a knowledge‐based force field in which the energy functions are conditional on local sequence patterns, as expressed in the hidden Markov model for local structure (HMMSTR). Carbon‐alpha force field (CALF) builds sequence specific statistical potentials based on database frequencies for α‐carbon virtual bond opening and dihedral angles, pair‐wise contacts and hydrogen bond donor‐acceptor pairs, and simulates folding via Brownian dynamics. We introduce hydrogen bond donor and acceptor potentials as α‐carbon probability fields that are conditional on the predicted local sequence. Constant temperature simulations were carried out using 27 peptides selected as putative folding initiation sites, each 12 residues in length, representing several different local structure motifs. Each 0.6 μs trajectory was clustered based on structure. Simulation convergence or representativeness was assessed by subdividing trajectories and comparing clusters. For 21 of the 27 sequences, the largest cluster made up more than half of the total trajectory. Of these 21 sequences, 14 had cluster centers that were at most 2.6 Å root mean square deviation (RMSD) from their native structure in the corresponding full‐length protein. To assess the adequacy of the energy function on nonlocal interactions, 11 full length native structures were relaxed using Brownian dynamics simulations. Equilibrated structures deviated from their native states but retained their overall topology and compactness. A simple potential that folds proteins locally and stabilizes proteins globally may enable a more realistic understanding of hierarchical folding pathways. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Nucleotide‐dependence of G‐actin conformation from multiple molecular dynamics simulations and observation of a putatively polymerization‐competent superclosed state
Authors: Splettstoesser Thomas , Noé Frank , Oda Toshiro , Smith Jeremy C.
Published: December 2008

The assembly of monomeric G‐actin into filamentous F‐actin is nucleotide dependent: ATP‐G‐actin is favored for filament growth at the “barbed end” of F‐actin, whereas ADP‐G‐actin tends to dissociate from the “pointed end.” Structural differences between ATP‐ and ADP‐G‐actin are examined here using multiple molecular dynamics simulations. The “open” and “closed” conformational states of G‐actin in aqueous solution are characterized, with either ATP or ADP in the nucleotide binding pocket. With both ATP and ADP bound, the open state closes in the absence of actin‐bound profilin. The position of the nucleotide in the protein is found to be correlated with the degree of opening of the active site cleft. Further, the simulations reveal the existence of a structurally well‐defined, compact, “superclosed” state of ATP‐G‐actin, as yet unseen crystallographically and absent in the ADP‐G‐actin simulations. The superclosed state resembles structurally the actin monomer in filament models derived from fiber diffraction and is putatively the polymerization competent conformation of ATP‐G‐actin. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Big losses in ecosystem niches: how core firm decisions drive complementary product shakeouts
Authors: Pierce Lamar
Published: December 2008

This study examines shakeouts in the context of business ecosystems. Market turbulence generated by core firm decisions in competing differentiated ecosystems can generate financial losses and exit for complementary niche market firms. I develop hypotheses predicting which niche markets will suffer larger losses and be more susceptible to shakeouts, and how core firm decisions will drive complementor performance and survival. I then apply these hypotheses to brand‐based differentiated ecosystems in the automotive industry, where networks of suppliers, customers, and complementors surround car manufacturers. More specifically, I study the complementary niche market of automotive leasing, where manufacturers sway leasing markets through product change, entry, and subsidization. To test the hypotheses, I use a proprietary dataset of 200,000 individual car leases between 1997–2002 to identify how manufacturer product design and niche market entry drive complementor losses and exit. These data allow a unique opportunity to understand how the strategic choices of core firms can have substantial and often devastating effects on niche markets in their ecosystem. Further, the results suggest how the dynamic capabilities to adapt to core firm behavior might improve performance for certain niche market complementors. Copyright © 2008 John Wiley & Sons, Ltd.
Doing business in Malaysia
Authors: Julian Craig C. , Ahmed Zafar U.
Published: December 2008

The importance of international trade to the Malaysian economy can hardly be exaggerated. Trade represents a lifeline for the Malaysian economy. Export‐oriented industrialization in the 1990s converted the labor‐surplus economy into a labor‐deficit one and then back to a labor‐surplus one in 2000 and beyond. The incidence of poverty has fallen by half since the early 1980s. Trade has also contributed much to the structural transformation and modernization of the economy. Had Malaysia been a closed economy, Malaysia would have shared the same fate as some other less developed countries that remain economically backward. Its external trade policy has paved the way for greater inflows of foreign direct investment, as foreign direct investors are not so much interested in serving the small domestic market as serving the vast external market. The large inflows of foreign direct investment have conferred positive effects on the domestic economy. This has meant significant improvements in the overall living standards for the Malaysians. Internationalization has provided employment opportunities, thereby raising their living standards through higher and more stable earnings. © 2009 Wiley Periodicals, Inc.
Utility of breast ultrasonography in the diagnostic work‐up of precocious puberty and proposal of a prognostic index for identifying girls with rapidly progressive central precocious puberty
Authors: Calcaterra V. , Sampaolo P. , Klersy C. , Larizza D. , Alfei A. , Brizzi V. , Beneventi F. , Cisternino M.
Published: December 2008

Objective

To determine the utility of breast ultrasono‐ graphy in the diagnostic work‐up of precocious puberty and to create a prognostic index for early differentiation between non/slowly progressive or transient forms of precocious puberty and rapidly progressive central precocious puberty.

Methods

We recruited consecutively 60 girls with precocious pubertal development. In all the girls we evaluated Tanner stage, basal and gonadotropin‐releasing hormone (GnRH)‐stimulated follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, estradiol (E2) levels, and bone age, and performed pelvis and breast ultrasound examinations. Logistic regression models were fitted to identify possible diagnostic factors for rapidly progressive central precocious puberty and non/slowly progressive or transient forms.

Results

Ultrasound breast volume ≥ 0.85 cm3 was associated with rapidly progressive central precocious puberty (P = 0.01). Uterine volume ≥ 5 cm3, LH peak ≥ 7 IU/L, presence of an endometrial echo, E2 levels ≥ 50 pmol/L and bone age > 2 SD above expected were significantly associated with rapidly progressive central precocious puberty. A multivariate model including uterine volume, E2 level, bone age, presence of an endometrial echo and ultrasound breast volume revealed a strong ability to classify rapidly progressive forms. From this multivariate analysis a prognostic index for rapidly progressive central precocious puberty was defined.

Conclusions

Ultrasound imaging allows better definition of the breast and the maturation stage than does use of Tanner's stages. Ultrasound breast volume ≥ 0.85 cm3 is an independent predicting factor of rapidly progressive central precocious puberty. A prognostic index that was created from a multivariate model including uterine volume, E2 level, presence of an endometrial echo, bone age and ultrasonographically determined breast volume, may help in the early differentiation between rapidly progressive central precocious puberty and non/slowly progressive or transient forms. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Carbohydrate Restriction has a More Favorable Impact on the Metabolic Syndrome than a Low Fat Diet
Authors: Volek Jeff S. , Phinney Stephen D. , Forsythe Cassandra E. , Quann Erin E. , Wood Richard J. , Puglisi Michael J. , Kraemer William J. , Bibus Doug M. , Fernandez Maria Luz , Feinman Richard D.
Published: December 2008

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12‐week study comparing two hypocaloric diets (~1,500 kcal): a carbohydrate‐restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low‐fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (−12%) and insulin (−50%) concentrations, insulin sensitivity (−55%), weight loss (−10%), decreased adiposity (−14%), and more favorable triacylglycerol (TAG) (−51%), HDL‐C (13%) and total cholesterol/HDL‐C ratio (−14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (−47%), the Apo B/Apo A‐1 ratio (−16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n‐7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin‐resistant states, and only the CRD decreased this marker (−20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.
NP7 protects from cell death induced by oxidative stress in neuronal and glial midbrain cultures from parkin null mice
Authors: Mena M.A. , Casarejos M.J. , Solano R. , Rodríguez-Navarro J.A. , Gómez A. , Rodal I. , Medina M. , de Yebenes J.G.
Published: December 2008

NP7, 5–10 μM, prevented the H2O2 induced apoptosis and necrosis of midbrain neuronal and glial cultures from WT and PK‐KO mice. NP7 suppressed microglial activation and the H2O2 induced drop‐out of dopamine neurons. Furthermore, NP7 prevented the increased phosphorylation of ERK and AKT induced by H2O2. NP7 may be a promising neuroprotector against oxidative stress in PD.
Identification of the gene transcription repressor domain of Gli3
Authors: Tsanev Robert , Tiigimägi Piret , Michelson Piret , Metsis Madis , Østerlund Torben , Kogerman Priit
Published: December 2008

Gli transcription factors are downstream targets of the Hedgehog signaling pathway. Two of the three Gli proteins harbor gene transcription repressor function in the N‐terminal half. We have analyzed the sequences and identified a potential repressor domain in Gli2 and Gli3 and have tested this experimentally. Overexpression studies confirm that the N‐terminal parts harbor gene repression activity and we mapped the minimal repressor to residues 106 till 236 in Gli3. Unlike other mechanisms that inhibit Gli induced gene transcription, the repressor domain identified here does not utilize Histone deacetylases (HDACs) to achieve repression, as confirmed by HDAC inhibition studies and pull‐down assays. This distinguishes the identified domain from other regulatory parts with negative influence on transcription.
Maternal mortality due to cardiac disease in Sri Lanka
Authors: Haththotuwa Hasanthi R. , Attygalle Deepika , Jayatilleka Anoma C. , Karunaratna Vineetha , Thorne Sara A.
Published: December 2008

Objective

To investigate Sri Lankan maternal deaths due to heart disease and to consider low‐cost interventions to reduce these deaths.

Methods

A qualitative study based on retrospective audit of all maternal deaths and late maternal deaths in Sri Lanka caused by cardiac disease in 2004.

Results

A total of 145 maternal deaths were recorded in 2004, for a maternal mortality rate of 38 per 100 000. There were 42 indirect deaths, 25 of which were due to cardiac disease; 23 deaths had a specific cardiac cause listed. Standard care was identified in prepregnancy counseling, contraception, and prenatal community and specialist care.

Conclusion

Cardiac disease is a major cause of maternal mortality in Sri Lanka, second only to postpartum hemorrhage. Rheumatic mitral valve disease is responsible for more than a third of maternal deaths from cardiac disease. Substandard care was identified in all cases; strategies to improve care could allow a reduction in maternal cardiac deaths.
Analysis of the thermal plumes in turbulent Rayleigh–Bénard convection based on well-resolved numerical simulations
Authors: KACZOROWSKI M. , WAGNER C.
Published: December 2008

In this study, direct numerical simulations and high-resolved large eddy simulations of turbulent Rayleigh–Bénard convection were conducted with a fluid of Prandtl number Pr = 0.7 in a long rectangular cell of aspect ratio unity in the cross-section and periodic boundaries in a horizontal longitudinal direction. The analysis of the thermal and kinetic energy spectra suggests that temperature and velocity fields are correlated within the thermal boundary layers and tend to be uncorrelated in the core region of the flow. A tendency of decorrelation of the temperature and velocity fields is also observed for increasing Ra when the flow has become fully turbulent, which is thought to characterize this regime. This argument is also supported by the analysis of the correlation of the turbulent fluctuations |u|′ and θ′. The plume and mixing layer dominated region is found to be separated from the thermal dissipation rates of the bulk and conductive sublayer by the inflection points of the probability density function (PDF). In order to analyse the contributions of bulk, boundary layers and plumes to the mean heat transfer, the thermal dissipation rate PDFs of four different Ra are integrated over these three regions. Hence, it is shown that the core region is dominated by the turbulent fluctuations of the thermal dissipation rate throughout the range of simulated Ra, whereas the contributions from the conductive sublayer due to turbulent fluctuations increase rapidly with Ra. The latter contradicts results by He, Tong & Xia (Phys. Rev. Lett., vol. 98, 2007). The results also show that the plumes and mixing layers are increasingly dominated by the mean gradient contributions. The PDFs of the core region are compared to an analytical scaling law for passive scalar turbulence which is found to be in good agreement with the results of the present study. It is noted that the core region scaling seems to approach the behaviour of a passive scalar as Ra increases, i.e. it changes from pure exponential to a stretched exponential scaling.
Simulating deformable particle suspensions using a coupled lattice-Boltzmann and finite-element method
Authors: MacMECCAN ROBERT M. , CLAUSEN J. R. , NEITZEL G. P. , AIDUN C. K.
Published: December 2008

A novel method is developed to simulate suspensions of deformable particles by coupling the lattice-Boltzmann method (LBM) for the fluid phase to a linear finite-element analysis (FEA) describing particle deformation. The methodology addresses the need for an efficient method to simulate large numbers of three-dimensional and deformable particles at high volume fraction in order to capture suspension rheology, microstructure, and self-diffusion in a variety of applications. The robustness and accuracy of the LBM–FEA method is demonstrated by simulating an inflating thin-walled sphere, a deformable spherical capsule in shear flow, a settling sphere in a confined channel, two approaching spheres, spheres in shear flow, and red blood cell deformation in flow chambers. Additionally, simulations of suspensions of hundreds of biconcave red blood cells at 40% volume fraction produce continuum-scale physics and accurately predict suspension viscosity and the shear-thinning behaviour of blood. Simulations of fluid-filled spherical capsules which have red-blood-cell membrane properties also display deformation-induced shear-thinning behaviour at 40% volume fraction, although the suspension viscosity is significantly lower than blood.
Electromagnetic control of thermal convection of a fluid with strongly temperature-dependent material properties
Authors: GIESSLER CORNELIA , THESS ANDRÉ
Published: December 2008

We study a one-dimensional model describing buoyancy-driven laminar steady flow of a glass melt in a closed loop under the influence of a localized electromagnetic (Lorentz) force. The loop is a highly simplified representation of a closed streamline in glass melt flow in a real furnace under the influence of an artificially produced Lorentz force. The model is based on the energy equation for the temperature and the Stokes equation for the velocity distribution inside the loop. We take into account the full nonlinear temperature dependence of the viscosity and the electrical conductivity of the melt. The three-dimensional problem is then reduced to a single nonlinear equation for the cross-section averaged velocity from which the one-dimensional temperature distribution along the loop can be readily obtained. We show that the two-way interaction between the velocity and temperature resulting from the temperature-dependent material properties and Lorentz force leads to the result that the mean velocity as a function of the control parameters is non-unique and involves bifurcations. For some parameters we even observe freezing, which refers to a regime in which the fluid is almost at rest. Our model reveals the role of temperature-dependent viscosity and conductivity in glass melt flows in a pure form that is not visible in full numerical simulations.
Four-wave resonant interactions in the classical quadratic Boussinesq equations
Authors: ONORATO M. , OSBORNE A. R. , JANSSEN P. A. E. M. , RESIO D.
Published: December 2008

We investigate theoretically the irreversibile energy transfer in flat bottom shallow water waves. Starting from the oldest weakly nonlinear dispersive wave model in shallow water, i.e. the original quadratic Boussinesq equations, and by developing a statistical theory (kinetic equation) of the aforementioned equations, we show that the four-wave resonant interactions are naturally part of the shallow water wave dynamics. These interactions are responsible for a constant flux of energy in the wave spectrum, i.e. an energy cascade towards high wavenumbers, leading to a power law in the wave spectrum of the form of k−3/4. The nonlinear time scale of the interaction is found to be of the order of (h/a)4 wave periods, with a the wave amplitude and h the water depth. We also compare the kinetic equation arising from the Boussinesq equations with the arbitrary-depth Hasselmann equation and show that, in the limit of shallow water, the two equations coincide. It is found that in the narrow band case, both in one-dimensional propagation and in the weakly two-dimensional case, there is no irreversible energy transfer because the coupling coefficient in the kinetic equation turns out to be identically zero on the resonant manifold.
Responses of Bingham-plastic muddy seabed to a surface solitary wave
Authors: CHAN I-CHI , LIU PHILIP L.-F.
Published: December 2008

In this paper, we investigate the dynamics of muddy-seabed motions induced by a surface solitary wave. The muddy seabed is characterized as Bingham-plastic mud. We focus our attention on the situations where the horizontal scale of the wave-induced mud flow is much larger than the vertical scale. The thickness of the mud layer is also assumed to be much smaller than the water depth above. With these simplifications, the dynamic pressure in the mud column remains a constant and the vertical displacement of the water–mud interface is negligible. The horizontal gradient of the wave-induced dynamic pressure along the water–seabed interface drives the motions in the mud bed. For a Bingham-plastic muddy seafloor, the mud moves either like a solid (plug flow) or like a viscous fluid (shear flow) depending on whether the magnitude of shear stress is in excess of the yield stress. Velocities inside these two different flow regimes and the location(s) of the yield surface(s) vary in time as functions of water–mud interfacial pressure gradient and the properties of the Bingham-plastic mud. A semi-analytical approach is developed in this paper to analyse the motions inside the mud bed under a surface solitary wave loading. Three possible scenarios are discussed to illustrate the complexity of the seafloor responses. The formula for the damping rate caused by the energy dissipation inside the muddy seabed is also derived. Using realistic values of the physical parameters, the present results for damping rate agree qualitatively with the available field observations.
Double-averaging analysis and local flow characterization of near-bed turbulence in gravel-bed channel flows
Authors: MIGNOT EMMANUEL , BARTHELEMY E. , HURTHER D.
Published: December 2008

This investigation focuses on the characteristics of near-bed turbulence in fully rough gravel-bed open-channel flows. The analysis combines results obtained with the double-averaging methodology and local flow characterization, using velocity measurements provided by a high-resolution three-axis Acoustic Doppler Velocity Profiler (ADVP). As a result of the flow heterogeneity induced by the bed topography, the flow is not locally uniform in the near-bed region, and a double-averaging methodology is applied over a length scale much greater than the gravel size. In smooth- and rough-bed flow conditions, without macro-roughness bed elements, maximum turbulent kinetic energy (TKE) production occurs very close to z = 0, while in our case with fully rough flows with macro-roughness elements, maximum turbulence activity is found to occur at gravel crest levels zc (zc/h = 0.1). Turbulent diffusion also reaches a maximum at this elevation. The characteristics of the spatially averaged TKE budget are in good agreement with those obtained in flows over canopies. The hydrodynamic double-averaged properties have strong similarities with mixing layers and reattached mixing layers in flows over backward facing steps. Local time-averaged velocity profiles can be split into three typical classes, namely log, S-shaped and accelerated. It appears that the S-shaped class profiles, located in the wakes of the macro-roughness elements, exhibit an inflectional profile typical of mixing layers. They are of major importance in the double-averaged TKE budget, as they provide a local high contribution to the double-averaged TKE flux, TKE production and dissipation compared to the log class profiles. Consequently, double-averaged TKE production is roughly 75% greater than the dissipation rate at the point of maximal TKE production. Moreover the macro-roughness bed elements imply mixing-layer-type hydrodynamics that play a dominant role in the overall structure of mean near-bed turbulence of gravel-bed channel flows.
Study of plasma parameters in a staged pinch device using current-stepping technique
Authors: DEEBA FARAH , AHMED KAMALUDDIN , HASEEB MAHNAZ QADAR , MIRZA ARSHAD M.
Published: December 2008

The implosion dynamics and fusion parameters of a high density D-T fibre plasma driven by Z-pinch with current stepping technique is investigated. Our numerical results demonstrate that a current-stepping technique reduces the minimum pinch radius, and as a result high density, high temperature plasma can be formed. Thus a staged pinch device with current-stepping technique can be used as an alternative approach to achieve fusion conditions with relatively small values of discharge current and with a long pulse duration.
Neurocognitive impairment in unaffected siblings of youth with bipolar disorder
Authors: Doyle A. E. , Wozniak J. , Wilens T. E. , Henin A. , Seidman L. J. , Petty C. , Fried R. , Gross L. M. , Faraone S. V. , Biederman J.
Published: December 2008

Background

There is growing evidence for the familiality of pediatric bipolar disorder (BPD) and its association with impairments on measures of processing speed, verbal learning and ‘executive’ functions. The current study investigated whether these neurocognitive impairments index the familial risk underlying the diagnosis.

Method

Subjects were 170 youth with BPD (mean age 12.3 years), their 118 non-mood-disordered siblings and 79 non-mood-disordered controls. Groups were compared on a battery of neuropsychological tests from the Wechsler Intelligence Scales, the Stroop Color Word Test, the Wisconsin Card Sorting Test (WCST), the Rey–Osterrieth Complex Figure (ROCF), an auditory working memory Continuous Performance Test (CPT) and the California Verbal Learning Test – Children's Version (CVLT-C). Measures were factor analyzed for data reduction purposes. All analyses controlled for age, sex and attention-deficit/hyperactivity disorder (ADHD).

Results

Principal components analyses with a promax rotation yielded three factors reflecting: (1) processing speed/verbal learning, (2) working memory/interference control and (3) abstract problem solving. The CPT working memory measure with interference filtering demands (WM INT) was only administered to subjects aged ⩾12 years and was therefore analyzed separately. BPD youth showed impairments versus controls and unaffected relatives on all three factors and on the WM INT. Unaffected relatives exhibited impairments versus controls on the abstract problem-solving factor and the WM INT. They also showed a statistical trend (p=0.07) towards worse performance on the working memory/interference control factor.

Conclusions

Neurocognitive impairments in executive functions may reflect the familial neurobiological risk mechanisms underlying pediatric BPD and may have utility as endophenotypes in molecular genetic studies of the condition.
Fibrils with parallel in-register structure constitute a major class of amyloid fibrils: molecular insights from electron paramagnetic resonance spectroscopy
Authors: Margittai Martin , Langen Ralf
Published: December 2008

The deposition of amyloid- and amyloid-like fibrils is the main pathological hallmark of numerous protein misfolding diseases including Alzheimer's disease, transmissible spongiform encephalopathy, and type 2 diabetes. Besides the well-established role in disease, recent work on a variety of organisms ranging from bacteria to humans suggests that amyloid fibrils can also convey biological functions. To better understand the molecular mechanisms by which amyloidogenic proteins misfold in disease or perform biological functions, structural information is essential. Although high-resolution structural analysis of amyloid fibrils has been challenging, a combination of biophysical approaches is beginning to unravel the various structural features of amyloid fibrils. Here we review these recent developments with particular emphasis on amyloid fibrils that have been studied using site-directed spin labeling and electron paramagnetic resonance spectroscopy. This approach has been used to define the precise location of fibril-forming core regions and identify local secondary structures within such core regions. Perhaps one of the most remarkable findings arrived at by site-directed spin labeling was that most fibrils that contain an extensive core region of ∼20 amino acids or more share a common parallel in-register arrangement of β strands. The preference for this arrangement can be explained on topological grounds and may be rationalized by the maximization of hydrophobic contact surface.
Math schemata and the origins of number representations
Authors: Carey Susan
Published: December 2008

The contrast Rips et al. draw between “bottom-up” and “top-down” approaches to understanding the origin of the capacity for representing natural number is a false dichotomy. Its plausibility depends upon the sketchiness of the authors' own proposal. At least some of the proposals they characterize as bottom-up are worked-out versions of the very top-down position they advocate. Finally, they deny that the structures that these putative bottom-up proposals consider to be sources of natural number are even precursors of concepts of natural number. This denial depends upon an idiosyncratic, and mistaken, idea of what a precursor is.
From magnitude to natural numbers: A developmental neurocognitive perspective
Authors: Kadosh Roi Cohen , Walsh Vincent
Published: December 2008

In their target article, Rips et al. have presented the view that there is no necessary dependency between natural numbers and internal magnitude. However, they do not give enough weight to neuroimaging and neuropsychological studies. We provide evidence demonstrating that the acquisition of natural numbers depends on magnitude representation and that natural numbers develop from a general magnitude mechanism in the parietal lobes.
Neo-Fregeanism naturalized: The role of one-to-one correspondence in numerical cognition
Authors: Decock Lieven
Published: December 2008

Rips et al. argue that the construction of math schemas roughly similar to the Dedekind/Peano axioms may be necessary for arriving at arithmetical skills. However, they neglect the neo-Fregean alternative axiomatization of arithmetic, based on Hume's principle. Frege arithmetic is arguably a more plausible start for a top-down approach in the psychological study of mathematical cognition than Peano arithmetic.