bluuebunny/crossref_metadata_2025 huggingface dataset:
NORMAL MODE ANALYSIS OF A SINGLE-WALLED CARBON NANOTUBE BASED ON MOLECULAR DYNAMIC: A SINGULAR VALUE DECOMPOSITION STUDY
Authors: NEGI S. , CHATURVEDI S.
Published: January 2011

The complete set of significant normal modes of a single-walled carbon nanotube has been extracted using singular value decomposition analysis of this molecular dynamics data. The first part of this study focuses on an isolated single-walled carbon nanotube performed with NVE Molecular Dynamic simulations. Singular value decomposition analysis is then done on this data. Normal modes are excited with an initial radial stretching given to all the atomic coordinates. For the case with 5% initial radial stretching given to the carbon nanotube, the two strongest modes involve radial breathing motion combined with a very slow rotational motion of individual rings of the nanotube. There is good agreement between the calculated frequency of radial breathing modes and published experimental measurements, as also the inverse scaling of this frequency with tube diameter. The coupling between these two motions weakens for a smaller initial perturbation. The next eight most significant modes are divided into two classes. The first class is characterized by mz = 0, i.e., axial uniformity and produces azimuthal variation in the radial positions of atoms, with a finite azimuthal mode number. The second class of modes has mθ = 0, with mz = 1 and 2, are with radial uniformity and leads to shifts in the X- and Y-centroid locations of different rings. Mode frequency and the associated spatial distortion are thus obtained for all the above-mentioned modes. Under NPT conditions, similar to laboratory conditions, i.e., at a constant temperature and pressure, mode frequencies change only slightly, but the hierarchy of modes is slightly different. External excitation produced at one of the normal mode frequencies, corresponding to centroid motion with (mθ = 0, mz = 1), shows a significant and steady increase in the amplitude of centroid displacement. Excitation at the second harmonic frequency leads to an initial increase in displacement amplitude, but eventual saturation. These conclusions are important for the application of carbon nanotubes in nanodevices, e.g., as nanomotors.
POLARIZABILITY AND SECOND HYPERPOLARIZABILITY OF SEMICONDUCTING SINGLE-WALL CARBON NANOTUBES
Authors: YAGHOBI MOJTABA
Published: January 2011

Considering the exciton effect, the polarizability and second polarizability spectra of semiconducting single-wall carbon nanotubes (S-SWCNTs) have been calculated by PPP (Pariser, Parr, and Pople) approximation and the single-excitation configuration interaction (single-CI) method and sum-over-state method. We have studied the nonlinear optical (NLO) properties of the S-SWCNTs with different lengths and diameters. The highest and first peak positions, bandgap, and the spectra shape of the polarizability and second hyperpolarizability change as N (the number of atoms) increases. Also, the peak values of γzzzz are very bigger than that for γxxxx. Our results indicate that the nonlinear optical properties of fullerenes are similar to S-SWCNTs.
Technique for High-Rate, Low-Temperature Deposition of TiO2 Photocatalytic Thin Film Using Radical-Assisted Sputtering
Authors: Noguchi Daisuke , Eto Tomohiro , Kodama Kazuya , Higashimaru Yukie , Fukudome Shoji , Kawano Yoshihiko , Sei Fumihiro , Siono Ichiro
Published: January 2011

We have developed a two-step deposition technique. In the first step, a TiO2 nucleus is formed on a SiO2 thin film by radical-assisted sputtering using reactive-mode sputtering and O2 radicals. The second step is a growth step where TiO2 is deposited at a high rate and at a low temperature on the nucleation layer using metallic-mode sputtering and O2 radicals. The results were evaluated by transmission electron microscopy. They demonstrate that this deposition method can form TiO2 thin films with high crystallinities from the growth boundary. The effectiveness of this method was also demonstrated by measuring the photocatalytic properties.
Buffer capacity computation for throughput-constrained modal task graphs
Authors: Wiggers Maarten H. , Bekooij Marco J. G. , Smit Gerard J. M.
Published: January 2011

Increasingly, stream-processing applications include complex control structures to better adapt to changing conditions in their environment. This adaptivity often results in task execution rates that are dependent on the processed stream. Current approaches to compute buffer capacities that are sufficient to satisfy a throughput constraint have limited applicability in case of data-dependent task execution rates.

In this article, we present a dataflow model that allows tasks to have loops with an unbounded number of iterations. For instances of this dataflow model, we present efficient checks on their validity. Furthermore, we present an efficient algorithm to compute buffer capacities that are sufficient to satisfy a throughput constraint.

This allows to guarantee satisfaction of a throughput constraint over different modes of a stream processing application, such as the synchronization and synchronized modes of a digital radio receiver.
Sysfier
Authors: Razavi Niloofar , Behjati Razieh , Sabouri Hamideh , Khamespanah Ehsan , Shali Amin , Sirjani Marjan
Published: January 2011

SystemC is a system-level modeling language that can be used effectively for hardware/software co-design. Since a major goal of SystemC is to enable verification at higher levels of abstraction, the tendency is now directing to introducing formal verification approaches for SystemC. In this article, we propose an approach for formal verification of SystemC designs, and provide the semantics of SystemC using Labeled Transition Systems (LTS) for this purpose. An actor-based language, Rebeca, is used as an intermediate language. SystemC designs are mapped to Rebeca models and then Rebeca verification toolset is used to verify LTL and CTL properties. To tackle the state-space explosion, Rebeca model checkers offer some reduction policies that make them appropriate for SystemC verification. The approach also benefits from the modular verification and program slicing techniques applied on Rebeca models. To show the applicability of our approach, we verified a single-cycle MIPS design and two hardware/software co-designs. The results show that our approach can effectively be used both in hardware and hardware/software co-verification.
Component-based modeling and verification of dynamic adaptation in safety-critical embedded systems
Authors: Adler Rasmus , Schaefer Ina , Trapp Mario , Poetzsch-Heffter Arnd
Published: January 2011

Adaptation is increasingly used in the development of safety-critical embedded systems, in particular to reduce hardware needs and to increase availability. However, composing a system from many reconfigurable components can lead to a huge number of possible system configurations, inducing a complexity that cannot be handled during system design. To overcome this problem, we propose a new component-based modeling and verification method for adaptive embedded systems. The component-based modeling approach facilitates abstracting a composition of components to a hierarchical component. In the hierarchical component, the number of possible configurations of the composition is reduced to a small number of hierarchical configurations. Only these hierarchical configurations have to be considered when the hierarchical component is used in further compositions such that design complexity is reduced at each hierarchical level. In order to ensure well-definedness of components, we provide a model of computation enabling the formal verification of critical requirements of the adaptation behavior.
Dynamic alteration schemes of real-time schedules for I/O device energy efficiency
Authors: Seo Euiseong , Kim Sangwon , Park Seonyeong , Lee Joonwon
Published: January 2011

Many I/O devices provide multiple power states known as the dynamic power management (DPM) feature. However, activating from sleep state requires significant transition time and this obstructs utilizing DPM in nonpreemptive real-time systems. This article suggests nonpreemptive real-time task scheduling schemes maximizing the effectiveness of the I/O device DPM support. First, we introduce a runtime schedulability check algorithm for nonpreemptive real-time systems that can check whether a modification from a valid schedule is still valid. By using this, we suggest three heuristic algorithms. The first algorithm reorders the execution sequence of tasks according to the similarity of their required device sets. The second one gathers dispersed short idle periods into one long idle period to extend sleeping state of I/O devices and the last one inserts an idle period between two consecutively scheduled tasks to prepare the required devices of a task right before the starting time of the task. The suggested schemes were evaluated for both the real-world task sets and the hypothetical task sets with simulation and the results showed that the suggested algorithms produced better energy efficiency than the existing comparative algorithms.
Parametric timing analysis and its application to dynamic voltage scaling
Authors: Mohan Sibin , Mueller Frank , Root Michael , Hawkins William , Healy Christopher , Whalley David , Vivancos Emilio
Published: January 2011

Embedded systems with real-time constraints depend on a priori knowledge of worst-case execution times (WCETs) to determine if tasks meet deadlines. Static timing analysis derives bounds on WCETs but requires statically known loop bounds.

This work removes the constraint on known loop bounds through parametric analysis expressing WCETs as functions. Tighter WCETs are dynamically discovered to exploit slack by dynamic voltage scaling (DVS) saving 60% to 82% energy over DVS-oblivious techniques and showing savings close to more costly dynamic-priority DVS algorithms.

Overall, parametric analysis expands the class of real-time applications to programs with loop-invariant dynamic loop bounds while retaining tight WCET bounds.
Reliability-aware dynamic energy management in dependable embedded real-time systems
Authors: Zhu Dakai
Published: January 2011

Recent studies show that voltage scaling, which is an efficient energy management technique, has a direct and negative effect on system reliability because of the increased rate of transient faults (e.g., those induced by cosmic particles). In this article, we propose energy management schemes that explicitly take system reliability into consideration. The proposed reliability-aware energy management schemes dynamically schedule recoveries for tasks to be scaled down to recuperate the reliability loss due to energy management. Based on the amount of available slack, the application size, and the fault rate changes, we analyze when it is profitable to reclaim the slack for energy savings without sacrificing system reliability. Checkpoint technique is further explored to efficiently use the slack. Analytical and simulation results show that the proposed schemes can achieve comparable energy savings as ordinary energy management schemes (which are reliability-ignorant) while preserving system reliability. The ordinary energy management schemes that ignore the effects of voltage scaling on fault rate changes could lead to drastically decreased system reliability.
System Administration Soft Skills
Authors: Lear Christina
Published: January 2011

System administration can be both stressful and rewarding. Stress generally comes from outside factors such as conflict between SAs (system administrators) and their colleagues, a lack of resources, a high-interrupt environment, conflicting priorities, and SAs being held responsible for failures outside their control. What can SAs and their managers do to alleviate the stress? There are some well-known interpersonal and time-management techniques that can help, but these can be forgotten in times of crisis or just through force of habit. The purpose of this article is to restate these maxims and remind readers of these important soft skills, particularly as they apply to SAs.
Fluid Dynamics of Dissolved Polymer Molecules in Confined Geometries
Authors: Graham Michael D.
Published: January 2011

The past decade has seen a renaissance in the study of polymer solutions flowing in confined geometries, the renaissance driven in part by advances in visualization of large DNA molecules and the desire to manipulate DNA for genomic applications. This article summarizes the features of the fundamental polymer physics and fluid dynamics that are relevant to the flow of confined polymer solutions, then reviews the recent literature on the topic. Experiments have clarified and extended prior work showing that diffusion of confined flexible polymers is substantially altered by confinement and that, during flow, polymers exhibit substantial cross-stream migration. Simulation methods have been developed that have the capability of capturing both polymer and fluid motion in confined geometries and yield results that are in semiquantitative agreement with experiments in dilute solutions. Kinetic-theory treatments of simple polymer models have led to analytically tractable models that qualitatively encompass the key phenomena observed in experiment.
Actuators for Active Flow Control
Authors: Cattafesta Louis N. , Sheplak Mark
Published: January 2011

Actuators are transducers that convert an electrical signal to a desired physical quantity. Active flow control actuators modify a flow by providing an electronically controllable disturbance. The field of active flow control has witnessed explosive growth in the variety of actuators, which is a testament to both the importance and challenges associated with actuator design. This review provides a framework for the discussion of actuator specifications, characteristics, selection, design, and classification for aeronautical applications. Actuator fundamentals are discussed, and various popular actuator types used in low-to-moderate speed flows are then described, including fluidic, moving object/surface, and plasma actuators. We attempt to highlight the strengths and inevitable drawbacks of each and highlight potential future research directions.
Fluid-Structure Interaction in Internal Physiological Flows
Authors: Heil Matthias , Hazel Andrew L.
Published: January 2011

We provide a selective review of recent progress in the analysis of several physiological and physiologically inspired fluid-structure interaction problems, our aim being to explain the underlying physical mechanisms that cause the observed behaviors. Specifically, we discuss recent studies of self-excited oscillations in collapsible tubes, focusing primarily on studies of an idealized model system, the Starling resistor—a device used in most laboratory experiments. We next review studies of a particular physiological, flow-induced oscillation: vocal-fold oscillations during phonation. Finally, we discuss the closure and reopening of pulmonary airways, physiological fluid-structure interaction problems that also involve the airways' liquid lining.
Global Linear Instability
Authors: Theofilis Vassilios
Published: January 2011

This article reviews linear instability analysis of flows over or through complex two-dimensional (2D) and 3D geometries. In the three decades since it first appeared in the literature, global instability analysis, based on the solution of the multidimensional eigenvalue and/or initial value problem, is continuously broadening both in scope and in depth. To date it has dealt successfully with a wide range of applications arising in aerospace engineering, physiological flows, food processing, and nuclear-reactor safety. In recent years, nonmodal analysis has complemented the more traditional modal approach and increased knowledge of flow instability physics. Recent highlights delivered by the application of either modal or nonmodal global analysis are briefly discussed. A conscious effort is made to demystify both the tools currently utilized and the jargon employed to describe them, demonstrating the simplicity of the analysis. Hopefully this will provide new impulses for the creation of next-generation algorithms capable of coping with the main open research areas in which step-change progress can be expected by the application of the theory: instability analysis of fully inhomogeneous, 3D flows and control thereof.
Wave Turbulence
Authors: Newell Alan C. , Rumpf Benno
Published: January 2011

In this article, we state and review the premises on which a successful asymptotic closure of the moment equations of wave turbulence is based, describe how and why this closure obtains, and examine the nature of solutions of the kinetic equation. We discuss obstacles that limit the theory's validity and suggest how the theory might then be modified. We also compare the experimental evidence with the theory's predictions in a range of applications. Finally, and most importantly, we suggest open challenges and encourage the reader to apply and explore wave turbulence with confidence. The narrative is terse but, we hope, delivered at a speed more akin to the crisp pace of a Hemingway story than the wordjumblingtumbling rate of a Joycean novel.
Insulin signaling in retinal neurons is regulated within cholesterol-enriched membrane microdomains
Authors: Fox Todd E. , Young Megan M. , Pedersen Michelle M. , Giambuzzi-Tussey Sarah , Kester Mark , Gardner Thomas W.
Published: January 2011

Neuronal cell death is an early pathological feature of diabetic retinopathy. We showed previously that insulin receptor signaling is diminished in retinas of animal models of diabetes and that downstream Akt signaling is involved in insulin-mediated retinal neuronal survival. Therefore, further understanding of the mechanisms by which retinal insulin receptor signaling is regulated could have therapeutic implications for neuronal cell death in diabetes. Here, we investigate the role of cholesterol-enriched membrane microdomains to regulate PKC-mediated inhibition of Akt-dependent insulin signaling in R28 retinal neurons. We demonstrate that PKC activation with either a phorbol ester or exogenous application of diacylglycerides impairs insulin-induced Akt activation, whereas PKC inhibition augments insulin-induced Akt activation. To investigate the mechanism by which PKC impairs insulin-stimulated Akt activity, we assessed various upstream mediators of Akt signaling. PKC activation did not alter the tyrosine phosphorylation of the insulin receptor or IRS-2. Additionally, PKC activation did not impair phosphatidylinositol 3-kinase activity, phosphoinositide-dependent kinase phosphorylation, lipid phosphatase (PTEN), or protein phosphatase 2A activities. Thus, we next investigated a biophysical mechanism by which insulin signaling could be disrupted and found that disruption of lipid microdomains via cholesterol depletion blocks insulin-induced Akt activation and reduces insulin receptor tyrosine phosphorylation. We also demonstrated that insulin localizes phosphorylated Akt to lipid microdomains and that PMA reduces phosphorylated Akt. In addition, PMA localizes and recruits PKC isotypes to these cholesterol-enriched microdomains. Taken together, these results demonstrate that both insulin-stimulated Akt signaling and PKC-induced inhibition of Akt signaling depend on cholesterol-enriched membrane microdomains, thus suggesting a putative biophysical mechanism underlying insulin resistance in diabetic retinopathy.
Identification of the roles of conserved charged residues in the extracellular domain of an epithelial sodium channel (ENaC) subunit by alanine mutagenesis
Authors: Edelheit Oded , Hanukoglu Israel , Dascal Nathan , Hanukoglu Aaron
Published: January 2011

Epithelial sodium channels (ENaC) are composed of three homologous subunits whose extracellular domains (ECD) form a funnel that directs ions from the lumen into the pore of ENaC. To examine the roles of conserved charged residues (Asp, Glu, Arg, and Lys) on ECD, we mutated 16 residues in human α-ENaC to alanine. The modified cRNAs were expressed in Xenopus laevis oocytes together with wild-type β- and γ-ENaC. The effect of each mutation was examined on three parameters: amiloride-sensitive Na+ conductance (assayed by the two-electrode voltage-clamp method), Na+-dependent self-inhibition of ENaC, and oocyte cell surface expression of ENaC (quantitated by confocal microscopy of yellow fluorescent protein linked to γ-ENaC). Mutation of 13 of 16 residues reduced the ENaC Na+ conductance (to 40–80% of WT). Mutation of only six residues showed a significant effect on the Na+ self-inhibition time constant (τ). All 16 mutants showed a strong correlation between ENaC activity and oocyte surface expression ( r = 0.62). Exclusion of four mutants showing the greatest effect on self-inhibition kinetics (Glu250 and Arg350 with τ = ∼30% of WT, and Asp393 and Glu530 with τ = ∼170% of WT) increased the correlation to r = 0.87. In the ASIC1 homotrimeric model, the homologs of α-ENaC Asp400 and Asp446 are exposed on the protein surface far from the other two chains. The mutations of these two residues showed the strongest effect on cell surface expression but had no effect on self-inhibition. Control mutations to a homologous charged residue (e.g., Asp to Glu) did not significantly affect ENaC activity. Changes in the two parameters, Na+ self-inhibition and oocyte surface expression level, accounted for the magnitude of reduction in ENaC activity as a result of the mutation to Ala. These results establish that while some conserved charged residues are part of the structure responsible for Na+ self-inhibition, most are essential for transport to the oocyte cell surface.
Is Generalized Maternal Optimism or Pessimism During Pregnancy Associated with Unplanned Cesarean Section Deliveries in China?
Authors: Moyer Cheryl A. , Elsayed Yasmin , Zhu YuChun , Wei Yumei , Engmann Cyril M. , Yang Huixia
Published: January 2011

This research examines whether maternal optimism/pessimism is associated with unplanned Cesarean section deliveries in China. If so, does the association remain after controlling for clinical factors associated with C-sections? A sample of 227 mostly primiparous women in the third trimester of pregnancy was surveyed in a large tertiary care hospital in Beijing, China. Post-delivery data were collected from medical records. In bivariate analysis, both optimism and pessimism were related to unplanned c-section. However, when optimism and pessimism were entered into a regression model together, optimism was no longer statistically significant. Pessimism remained significant, even when adjusting for clinical factors such as previous abortion, previous miscarriage, pregnancy complications, infant gestational age, infant birthweight, labor duration, birth complications, and self-rated difficulty of the pregnancy. This research suggests that maternal mindset during pregnancy has a role in mode of delivery. However, more research is needed to elucidate potential causal pathways and test potential interventions.
Modulation of the Cellular Expression of Circulating Advanced Glycation End-Product Receptors in Type 2 Diabetic Nephropathy
Authors: Sourris Karly C. , Harcourt Brooke E. , Penfold Sally A. , Yap Felicia Y. T. , Morley Amy L. , Morgan Philip E. , Davies Michael J. , Baker Scott T. , Jerums George , Forbes Josephine M.
Published: January 2011

Background. Advanced glycation end-products (AGEs) and their receptors are prominent contributors to diabetic kidney disease.Methods. Flow cytometry was used to measure the predictive capacity for kidney impairment of the AGE receptors RAGE, AGE-R1, and AGE-R3 on peripheral blood mononuclear cells (PBMCs) in experimental models of type 2 diabetes (T2DM) fed varied AGE containing diets and in obese type 2 diabetic and control human subjects.Results. Diets high in AGE content fed to diabetic mice decreased cell surface RAGE on PBMCs and in type 2 diabetic patients with renal impairment (RI). All diabetic mice had elevated Albumin excretion rates (AERs), and high AGE fed dbdb mice had declining Glomerular filtration rate (GFR). Cell surface AGE-R1 expression was also decreased by high AGE diets and with diabetes in dbdb mice and in humans with RI. PBMC expression of AGE R3 was decreased in diabetic dbdb mice or with a low AGE diet.Conclusions. The most predictive PBMC profile for renal disease associated with T2DM was an increase in the cell surface expression of AGE-R1, in the context of a decrease in membranous RAGE expression in humans, which warrants further investigation as a biomarker for progressive DN in larger patient cohorts.
Preparation and Characterization of Nanozeolite NaA from Rice Husk at Room Temperature without Organic Additives
Authors: Ghasemi Zahra , Younesi Habibollah
Published: January 2011

Nanozeolite NaA was synthesized by the hydrothermal method with silica extracted from rice husk as silica source. Amorphous silica with 87.988 wt%  SiO2was extracted from rice husk ash by a suitable alkali solution. The effect of the crystallization time and the ratio ofNa2O/SiO2on the properties of the final product was investigated. The synthesized nanozeolite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) techniques, and Brunauer-Emmett-Teller (BET) method. Results revealed that the crystallization time and alkalinity have significant effects on the structural properties of nanozeolite. Nanocrystals NaA with crystal sizes ranging from 50 to 120 nm were synthesized at room temperature with 3 days aging, without adding any organic additives.
Carotid Plaque Morphology Improves Stroke Risk Prediction: Usefulness of a New Ultrasonographic Score
Authors: Prati P. , Tosetto A. , Casaroli M. , Bignamini A. , Canciani L. , Bornstein N. , Prati G. , Touboul P.J.
Published: January 2011

Carotid thickening and plaque detected by B-mode imaging ultrasound are useful to improve the ischemic risk evaluation in asymptomatic subjects over and beyond the traditional cardiovascular risk factors. Some plaque’s echographic parameters help describing the vascular risk. We hypothesized that the stenosis degree, plaque surface irregularity, echolucency and texture, compounded in a Total Plaque Risk Score (TPRS), are predictors of the ischemic events in the San Daniele study, a general population-based study of 1,348 subjects followed for 12 years in average. In the 171 subjects with at least one plaque at baseline, high TPRS was the most powerful independent predictor of cerebrovascular events, which occurred in 115 subjects. Addition of plaque characteristics significantly increased the area under the ROC curve (0.90 vs. 0.88, p = 0.04) versus the Framingham risk score alone. The TPRS is a potential new tool to improve the stroke risk prediction.
Involvement of Insulin-Like Growth Factor-I Secretion and All-Trans-Retinoic Acid-Induced Decrement in Viability in MCF-7 Cells
Authors: Oh Young-Il , Kim Jong-Hoon , Kang Chang-Won
Published: January 2011

Background/Aim: Insulin-like growth factor-I (IGF-I) is associated with survival, apoptosis and proliferation in MCF-7 cells. All-trans-retinoic acid (RA) is used as a cancer therapeutic, but the use of RA in cancer therapy is limited by the unpredictable resistance of cancer cells to drug action. Furthermore, the relationship of IGF-I with RA-induced decrement in cell viability has yet to be elucidated. Materials and Methods: MCF-7 cells were grown as confluent monolayers. To demonstrate the signaling pathways and roles of IGF-I, we suppressed endogenous target IGF-I with specific small interfering RNA treatment. Protein kinase C-δ and insulin receptor substrate 1 (IRS-1) protein levels were analyzed by Western blot. Radioimmunoassays were used to assess the concentration of endogenous IGF-I, and RT-PCR was used to assess IGF-I mRNA expression. Cell viability was analyzed with the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Results: We showed that RA treatment resulted in a dose- and time-dependent decrease in the secretion and synthesis of IGF-I. Subsequently, we found that suppression of IGF-I and IRS-1 protein decreased cell viability. In contrast, suppression of protein kinase C-δ and stimulation of IGF-I protected cells from RA-induced decrement in cell viability. The combination of RA treatment with IGF-I or IRS-1 small interfering RNA resulted in an additive decrease in cell viability. Conclusion: These results indicate that IGF-I plays an important role in the effect of RA and that suppression of IGF-I is implicated in the RA-induced inhibition of cell viability in MCF-7 cells.
Bilingual Language Acquisition: Where Does the Difference Lie?
Authors: Sebastian-Galles Nuria
Published: January 2011

Studies of preverbal infants exposed to a bilingual environment have unveiled the existence of important similarities, but also significant differences in the way monolinguals-to-be and bilinguals-to-be solve the problem of language acquisition. In this paper, I review these studies and I argue that some apparent bilingual failures are the consequence of experimental designs conceived to test monolingual infants. When properly analyzed, these data provide evidence for successful solutions to learning 2 languages and to become a competent adult bilingual speaker.
The Emergence of Two Functions for Spatial Devices in Nicaraguan Sign Language
Authors: Senghas Ann
Published: January 2011

The emergence of a new sign language since the late 1970s in Nicaragua enables us to capture the effects of successive cohorts of learners on an emerging grammar and to observe how elements are reshaped from one form and function to another. Here we document the contrastive use of a device that has been found to be central to the grammars of sign languages: the spatial modulation of signs. In Nicaraguan Sign Language, this device has two primary functions: expressing the participants of events (that is, indicating who), and describing locations and orientations of referents (that is, indicating where). We ask whether the two uses reduce to a single construction type, or if the more abstract who construction derived from the more iconic and concrete where construction. We compare the first two successive cohorts of deaf signers to acquire the language in its first decade. We find that as learners created new constructions to meet the new functions, they did not simply apply an already developed form more broadly, nor did they develop the more abstract application from the more iconic one. Instead, the more abstract who construction appears to have conventionalized first. Thus, the forms either emerged independently, or split very early in the 1980s, before either had developed as a consistently applied form.
Descemet’s Stripping with Endothelial Keratoplasty for Special Fuchs’ Endothelial Dystrophy in Phakic Eyes
Authors: Huang Ting , Luo Yan , Wang Yujuan , Hu Andina , Gao Na
Published: January 2011

Background: To determine the efficacy and postoperative complications of simple Descemet’s stripping endothelial keratoplasty (DSEK) for treatment of special Fuchs’ endothelial dystrophy in phakic eyes. Methods: Six eyes with clear crystalline lenses in 5 consecutive patients with Fuchs’ endothelial dystrophy underwent DSEK and were followed up for 12–27 months. The pupil was constricted preoperatively to 1.5 mm in diameter. The anterior chamber was deepened intraoperatively by injection of balanced salt solution to unfold the donor graft and to protect the crystalline lens. Best corrected visual acuity, corneal astigmatism, corneal curvature, corneal thickness, and anterior chamber depth were recorded preoperatively and at 6 and 12 months postoperatively. Average endothelial cell density and endothelial cell loss (ECL) were recorded at 6 and 12 months postoperatively. Results: DSEK was successfully performed in all 6 eyes. No graft dislocation or lens injury occurred. One of the 6 eyes presented with mild cataract at 12 months after surgery but showed no sign of progressive cataract development during the follow-up. All grafts were clear during the last follow-up: best corrected visual acuity ranged from 20/50 to 20/30, average corneal astigmatism was 2.2 ± 0.6 dpt, average corneal curvature was 46.0 ± 2.4 dpt, and average central corneal thickness was 583.0 ± 21.5 µm. At 6 and 12 months postoperatively, average endothelial cell density was 2,070.7 ± 206.1 cells/mm2 (28.0 ± 7.5% of ECL) and 1,838.3 ± 194.5 cells/mm2 (36.1 ± 6.2% of ECL), respectively. Conclusions: Simple DSEK might be a feasible option for Fuchs’ endothelial dystrophy in young patients with clear crystalline lenses.
Cerebrospinal Fluid Biomarkers in Alzheimer’s Disease Families with PSEN1 Mutations
Authors: Fortea Juan , Lladó Albert , Bosch Beatriz , Antonell Anna , Oliva Rafael , Molinuevo Jose Luis , Sánchez-Valle Raquel
Published: January 2011

Background/Aims: Familial Alzheimer’s disease allows studies in the preclinical phases of the disease. We studied cerebrospinal fluid (CSF) amyloid β1–42 (Aβ1–42), total tau (t-tau) and phospho-tau181 (p-tau) levels in PSEN1 families and correlated the results with the genetic status, age and clinical stage. Methods: Thirteen subjects from 3 families with 2 PSEN1 mutations (L286P, M139T) were recruited from the genetic counseling program for familial dementia. Eight mutation carriers (MC) and 5 noncarriers (NC) underwent clinical and cognitive evaluations. CSF concentrations were obtained by ELISA methodology. Results: Symptomatic MC presented reduced CSF Aβ1–42 (mean = 175 pg/ml) and elevated t-tau (mean = 635 pg/ml) compared to controls, but not asymptomatic MC (mean = 684 and 255 pg/ml, respectively) at a median of –12.8 years from the predicted disease onset (adjusted age). Aβ1–42 levels presented an inverse correlation with the adjusted age (r = –1, p < 0. 01) in asymptomatic MC, but not in symptomatic MC or NC. t-tau presented a trend towards a negative correlation with Mini Mental State Examination (MMSE; r = –0.949, p = 0.051) in symptomatic MC but not in asymptomatic MC. In the whole group of MC, t-tau presented a significant positive correlation with Clinical Dementia Rating sum of boxes (r = 0.913, p = 0.002) and a negative correlation with MMSE (r = –0.946, p < 0.001). Conclusions: CSF Aβ1–42 levels correlate with time to disease onset in asymptomatic MC to reach floor levels when symptoms appear. CSF t-tau levels become elevated in symptomatic MC and correlate with clinical severity. These findings may suggest that the changes in Aβ1–42 precede t-tau elevation in PSEN1 MC.
Investigation of the Molecular Structure of the Human Stratum Corneum Ceramides [NP] and [EOS] by Mass Spectrometry
Authors: Hinder A. , Schmelzer C.E.H. , Rawlings A.V. , Neubert R.H.H.
Published: January 2011

The aim of this study was to characterize the two ceramide (CER) subclasses CER[NP] and CER[EOS] of human stratum corneum and to identify the chemical structures of their subspecies. High-performance thin-layer chromatography and normal-phase high-performance liquid chromatography were used for the separation of CER fractions, whereas nanoelectrospray ionization tandem mass spectrometry was applied to investigate the chemical structures in detail. Thus, CER[EOS] fragmentation revealed that in addition to linoleic acid other esterified fatty acids occur in the ω-position. Of particular interest is the identification of a 17:2 fatty acid located in this part of the molecule. Several subspecies of CER[NP], including subspecies with odd numbers of carbon atoms in both chains, the non-α-hydroxylated fatty acid moiety (part N) and the phytosphingosine (part P), were identified. Furthermore, it was found that 12% of CER[NP] subspecies have an odd number of carbon atoms in both chains of the molecule. Similar results were obtained for CER[EOS]. Both the esterified fatty acid (part E) and the sphingosine base (part S) were found to contain odd-numbered chain lengths. These results underline the heterogeneity of the CER composition in the stratum corneum lipid bilayer.
Prenatal Complex Rhythmic Music Sound Stimulation Facilitates Postnatal Spatial Learning but Transiently Impairs Memory in the Domestic Chick
Authors: Kauser H. , Roy S. , Pal A. , Sreenivas V. , Mathur R. , Wadhwa S. , Jain S.
Published: January 2011

Early experience has a profound influence on brain development, and the modulation of prenatal perceptual learning by external environmental stimuli has been shown in birds, rodents and mammals. In the present study, the effect of prenatal complex rhythmic music sound stimulation on postnatal spatial learning, memory and isolation stress was observed. Auditory stimulation with either music or species-specific sounds or no stimulation (control) was provided to separate sets of fertilized eggs from day 10 of incubation. Following hatching, the chicks at age 24, 72 and 120 h were tested on a T-maze for spatial learning and the memory of the learnt task was assessed 24 h after training. In the posthatch chicks at all ages, the plasma corticosterone levels were estimated following 10 min of isolation. The chicks of all ages in the three groups took less (p < 0.001) time to navigate the maze over the three trials thereby showing an improvement with training. In both sound-stimulated groups, the total time taken to reach the target decreased significantly (p < 0.01) in comparison to the unstimulated control group, indicating the facilitation of spatial learning. However, this decline was more at 24 h than at later posthatch ages. When tested for memory after 24 h of training, only the music-stimulated chicks at posthatch age 24 h took a significantly longer (p < 0.001) time to traverse the maze, suggesting a temporary impairment in their retention of the learnt task. In both sound-stimulated groups at 24 h, the plasma corticosterone levels were significantly decreased (p < 0.001) and increased thereafter at 72 h (p < 0.001) and 120 h which may contribute to the differential response in spatial learning. Thus, prenatal auditory stimulation with either species-specific or complex rhythmic music sounds facilitates spatial learning, though the music stimulation transiently impairs postnatal memory.
Pulse Transit Time for Quantifying Inspiratory Effort in Patients with Obstructive Sleep Apnea
Authors: Huang Hui , Ye Jing-Ying , Li Yan-Ru , Wang Xiao-Yi , Zhang Yu-Huan , Wang Jiang-Yong , Ding Xiu , Li Hong-Guang , Han De-Min
Published: January 2011

Objectives: To investigate the feasibility of pulse transit time (PTT) as a quantitative measure of inspiratory effort in patients with obstructive sleep apnea (OSA). Methods: Nineteen moderate to severe OSA patients were included to undergo overnight polysomnography simultaneously with esophageal pressure (Pes) and PTT. The quantitative relationships between the size of Pes variations (ΔPes) and PTT variations (ΔPTT) on a breath-by-breath basis in obstructive apneas were assessed. Results: A total of 19,833 breaths from 6,087 obstructive apneas were analyzed. There were good correlations with r = 0.779 ± 0.095 (mean ± SD) between ΔPes and ΔPTT based on overnight sleep. The correlation coefficients for supine and lateral position were of the approximated magnitude (r = 0.783 ± 0.060 and 0.757 ± 0.106, respectively), whereas they were lower in rapid eye movement (REM) sleep (r = 0.564 ± 0.140) compared with non-rapid eye movement (NREM) sleep (r = 0.787 ± 0.071). In NREM sleep, the regression lines of ΔPTT against ΔPes were plotted with intercepts (5.1 ± 2.1 ms) and slopes (0.35 ± 0.08 ms·cm H2O–1). Conclusions: PTT showed good ability in detecting changes of inspiratory effort in overnight sleep and was proved to be a clinically useful method in quantifying increases in inspiratory effort in NREM sleep. Hence, PTT has prospects to become an alternative to Pes in respiratory sleep studies.
Cyclin-Dependent Kinase Inhibitor p16 and p21 Expression, and Cell Cycle Change in Human Lens Epithelial Cell Line SRA 01/04 following Contact Inhibition in Normal Culture
Authors: Yamashiro Yoko , Sasaki Hiroshi , Ibaraki Nobuhiro , Nagai Kota , Kawakami Yutaka , Yaguchi Hiromoto , Fujita Nobuyuki , Osada Hiromi , Sasaki Kazuyuki
Published: January 2011

Purpose: To describe the pattern of expression of the cyclin-dependent kinase inhibitors (CDKIs) p16, p21 and p27, and the cell cycle in SRA 01/04 cells relative to contact inhibition. Methods: SRA 01/04 cells were grown to overconfluence under normal conditions. At various phases of the cell growth, cells were assayed by flow cytometry and Western blotting for the expression of CDKIs. Results: Expression of p16 was detected from early logarithmic growth to stationary phases, during which the number of cells in G₀/G1 increased from 46 to 69%. Expression of p21 was detected only during the overgrowth phase, when 60% of the cells were in G₀/G1. Expression of p27 was not observed in SRA 01/04 cells. Conclusions: p16 expression was likely mediated by G₀/G1 arrest to induce contact inhibition in SRA 01/04. p21 expression may be related to withdrawal, and p27 deficiency may be related to the immortality of this cell line. It is possible for p16 to stop proliferation of lens epithelial cells like progressing posterior capsular opacification, by overexpression to mimic contact inhibition.
Adherence to Disease-Modifying Therapies in Spanish Patients with Relapsing Multiple Sclerosis: Two-Year Interim Results of the Global Adherence Project
Authors: Arroyo E. , Grau C. , Ramo-Tello C. , Parra J. , Sánchez-Soliño O. ,   on behalf of the GAP Study Group
Published: January 2011

The post-marketing international Global Adherence Project investigated adherence to disease-modifying therapy for relapsing-remitting multiple sclerosis. We report adherence data from the first 2 years in the Spanish subset of patients (n = 254 at baseline). The overall adherence rate was 85.4%. Patients taking intramuscular (IM) interferon-β (IFNβ)-1a were significantly more adherent (96.4%) compared with patients taking subcutaneous (SC) IFNβ-1a 22 µg (79.1%; p = 0.0064), SC IFNβ-1a 44 µg (79.6%; p = 0.0064) and glatiramer acetate (82.7%; p = 0.0184). At year 1 (n = 142), the overall adherence rate was 86.6%. Patients on IM IFNβ-1a were significantly more adherent than patients on SC IFNβ-1a 22 µg (93.9 vs. 66.7%; p = 0.0251). At year 2 (n = 131), the overall adherence rate was 82% (87.5% for IM IFNβ-1a, 80.0% for SC IFNβ-1a 22 µg, 77.8% for SC IFNβ-1a 44 µg, 85.2% for IFNβ-1b, and 80.0% for glatiramer acetate). In conclusion, adherence remained high among all disease-modifying therapies over the first 2 years of the study and was significantly higher for IM IFNβ-1a, at visit 1, compared with SC IFNβ-1a.
Morphological Evidence for a Change in the Pattern of Aortic Wall Shear Stress With Age
Authors: Bond Andrew R. , Iftikhar Saadia , Bharath Anil A. , Weinberg Peter D.
Published: January 2011

Objective—

The distribution of atherosclerosis around branch sites changes with age in human and rabbit aortas. We tested whether that reflects a change in the pattern of wall shear stress by examining shear-dependent morphological features of endothelial cells.

Methods and Results—

Endothelial cells and their nuclei align and elongate with applied shear. These parameters were examined in the descending thoracic aorta of immature and mature rabbits. The use of Häutchen preparations, fluorescent stains, and automated image analysis allowed nuclear morphology to be mapped reliably at high resolution over large areas. Cells and their nuclei were most elongated downstream of branch ostia in immature aortas but upstream of them in mature aortas. Elongation was generally greater in mature animals, and nuclei aligned toward the ostia more in these animals, consistent with a greater flow into the branch. Morphology away from branches was indicative of helical flow in the aorta, with greatest shear on the dorsal wall, at both ages.

Conclusion—

The data are consistent with age-related changes in the pattern of shear around aortic branches. Maps of nuclear elongation closely resembled maps of lesion frequency. The association was positive, implying that lesions occur at sites of high shear stress at both ages.
Autologous Bone-Marrow Mononuclear Cell Implantation Reduces Long-Term Major Amputation Risk in Patients With Critical Limb Ischemia
Authors: Idei Naomi , Soga Junko , Hata Takaki , Fujii Yuichi , Fujimura Noritaka , Mikami Shinsuke , Maruhashi Tatsuya , Nishioka Kenji , Hidaka Takayuki , Kihara Yasuki , Chowdhury Moniruddin , Noma Kensuke , Taguchi Akira , Chayama Kazuaki , Sueda Taijiro , Higashi Yukihito
Published: January 2011

Background—

Bone-marrow mononuclear cell (BM-MNC) implantation improves ischemic symptoms in patients with critical limb ischemia (CLI). The purpose of this study was to evaluate long-term clinical outcomes after autologous BM-MNC implantation in patients with CLI.

Methods and Results—

We assessed long-term clinical outcomes after BM-MNC implantation in 51 patients with CLI, including 25 patients with peripheral arterial disease (PAD) and 26 patients with Buerger disease. Forty-six CLI patients who had no BM-MNC implantation served as control subjects. Median follow-up period was 4.8 years. The 4-year amputation-free rates after BM-MNC implantation were 48% in PAD patients and 95% in Buerger disease, and they were 0% in control PAD patients and 6% in control Buerger disease. The 4-year overall survival rates after BM-MNC implantation were 76% in PAD patients and 100% in Buerger disease, and they were 67% in control PAD patients and 100% in control Buerger disease. Multivariable Cox proportional hazards analysis revealed that BM-MNC implantation correlated with prevention of major amputation and that hemodialysis and diabetes mellitus correlated with major amputation. In Buerger disease, ankle brachial pressure index and transcutaneous oxygen pressure were significantly increased after 1 month and remained high during 3-year follow-up. However, in patients with PAD, ankle brachial pressure index and transcutaneous oxygen pressure significantly increased after 1 month and gradually decreased during 3-year follow-up and returned to baseline levels.

Conclusions—

These findings suggest that BM-MNC implantation is safe and effective in patients with CLI, especially in patients with Buerger disease.

Clinical Trial Registration—

URL:
http://home.hiroshima-u.ac.jp/angio/
. Unique identifier: 001769.
Temporal changes in characteristics of populations originating from interbreeding between Bursaphelenchus xylophilus and B. mucronatus
Authors: Togashi Katsumi , Taga Yosuke , Goto Satomi , Matsunaga Koji
Published: January 2011

To determine the likelihood of introgressive hybridisation between Bursaphelenchus xylophilus and B. mucronatus, interbreeding experiments were performed. Of 240 trials involving 24 reciprocal crosses (ten trials per cross, ten virgin females and ten virgin males per trial) between three B. xylophilus isolates and four B. mucronatus isolates under conditions that allowed F1 hybrids to backcross with parents, 174 produced hybrid juveniles. The others failed to generate juveniles. Twenty trials in four crosses successfully established populations which persisted for 65.8-179.5 days, corresponding to 10-40 generations. Analyses of ribosomal DNA (rDNA) fragments for 20 hybrid-derived populations and analysis of inheritance mode of mitochondrial DNA indicated that three crosses produced populations whose members had the B. mucronatus nuclear genome and B. mucronatus or B. xylophilus cytoplasm, whereas the remaining interbreeding produced populations in which 79% of members examined had the B. xylophilus rDNA and cytoplasm and 17% had rDNA fragments of the two species. Populations composed of heterospecific cytonuclear individuals took longer to eat up Botrytis cinerea mycelial mat in a rearing flask than others. Formation of a tail tip mucro in adult females, a characteristic of B. mucronatus, was suggested to be controlled by nuclear and cytoplasmic genes. The results suggested that the introgression of B. xylophilus genes into the B. mucronatus genome was easier than introgression in the opposite direction.