bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Dynamic of a Geared Rotor System With Nonlinear Oil Film Force and Nonlinear Mesh Force
Authors: Cui Yahui , Liu Zhansheng , Wang Yongliang , Ye Jianhuai
Published: July 2012

To investigate the effect of oil film force on a geared rotor system, a short journal bearing model was applied to represent nonlinear oil film force. A dynamic model of the geared rotor oil journal bearing system was presented. The nonlinear gear mesh force and nonlinear oil film force were considered in the model. The nonlinear dynamic responses of the system were investigated by numerical integration method. This article shows that when the rotational speed is relatively low, the vibration of the system is mainly affected by nonlinear mesh force. With the increase of rotational speed, the influence of nonlinear oil film force also increases gradually, and the subsynchronous forward precession phenomena appear. When the speed increases to a certain value, the amplitude of the subsynchronous forward precession exceeds the amplitude of the rotational frequency, and the nonlinear mesh force is greatly affected by the nonlinear oil film force. However, the linear oil film force does not affect the nonlinear mesh force. The subsynchronous forward precession is difficult to be predicted by linear oil film force which was previously applied. This experiment is performed to validate the correctness of the dynamic model presented, and the numerical integration results of low speeds are validated by the experimental data.
On Power Flow Suppression in Straight Elastic Pipes by Use of Equally Spaced Eccentric Inertial Attachments
Authors: Sorokin Sergey , Holst-Jensen Ole
Published: July 2012

The paper addresses the power flow suppression in an elastic beam of the tubular cross section (a pipe) at relatively low excitation frequencies by deploying a small number of equally spaced inertial attachments. The methodology of boundary integral equations is used to obtain an exact solution of the problem in vibrations of this structure. The power flow analysis in a pipe with and without equally spaced eccentric inertial attachments is performed and the effect of suppression of the energy transmission is demonstrated theoretically. These results are put in the context of predictions from the classical Floquet theory for an infinitely long periodic structure. Parametric studies are performed to explore sensitivities of this effect to variations in the number of attachments. The theoretically predicted eigenfrequencies and insertion loss are compared with the dedicated experimental data.
Exact Vibration Solution for Exponentially Tapered Cantilever With Tip Mass
Authors: Wang C.Y. , Wang C. M.
Published: July 2012

This technical note is concerned with the free vibration problem of a cantilever beam with constant thickness and exponentially decaying width. Existing analytical results for such a vibration beam problem are found to be incomplete because lower frequencies could not be obtained. Presented herein is the exact characteristic equation for generating the complete vibration frequencies for the considered vibrating beam problem. Also the note treated for the first time such a tapered cantilever beam with a tip mass. The exact solutions (frequencies and mode shapes) are important to engineers designing such tapered beams and the results serve as benchmarks for assessing the validity, convergence and accuracy of numerical methods and solutions.
Parametric Instability of Planetary Gears Having Elastic Continuum Ring Gears
Authors: Parker Robert G. , Wu Xionghua
Published: July 2012

The parametric instability of planetary gears having elastic continuum ring gears is analytically investigated based on a hybrid continuous-discrete model. Mesh stiffness variations of the sun-planet and ring-planet meshes caused by the changing number of teeth in contact are the source of parametric instability. The natural frequencies of the time invariant system are either distinct or degenerate with multiplicity two, which indicates three types of combination instabilities: distinct-distinct, distinct-degenerate, and degenerate-degenerate instabilities. By using the structured modal properties of planetary gears and the method of multiple scales, the instability boundaries are obtained as simple expressions in terms of mesh parameters. Instability existence rules for in-phase and sequentially phased planet meshes are also discovered. For in-phase planet meshes, instability existence depends only on the type of gear mesh deformation. For sequentially phased planet meshes, the number of teeth on the sun (or the ring) and the type of gear mesh deformation govern the instability existence. The instability boundaries are validated numerically.
Application of a Weakly Nonlinear Absorber to Suppress the Resonant Vibrations of a Forced Nonlinear Oscillator
Authors: Ji J. C.
Published: July 2012

A weakly nonlinear vibration absorber is used to suppress the primary resonance vibrations of a single degree-of-freedom weakly nonlinear oscillator with periodic excitation, where the two linearized natural frequencies of the integrated system are not under any internal resonance conditions. The values of the absorber parameters are significantly lower than those of the forced nonlinear oscillator, as such the nonlinear absorber can be regarded as a perturbation to the nonlinear primary oscillator. The characteristics of the nonlinear primary oscillator change only slightly in terms of its new linearized natural frequency and the frequency interval of primary resonances after the nonlinear absorber is added. The method of multiple scales is employed to obtain the averaged equations that determine the amplitudes and phases of the first-order approximate solutions. Selection criteria are developed for the absorber linear stiffness (linearized natural frequency) and nonlinear stiffness in order to achieve better performance in vibration suppression. Illustrative examples are given to show the effectiveness of the nonlinear absorber in suppressing nonlinear vibrations of the forced oscillator under primary resonance conditions.
Remarks on Parametric Surface Waves in a Nonlinear and Non-Ideally Excited Tank
Authors: Navarro Helio A. , Balthazar José M. , Krasnopolskaya Tatyana S. , Shvets Aleksandr Yu. , Chavarette Fábio R.
Published: July 2012

We studied free surface oscillations of a fluid in a cylinder tank excited by an electric motor with limited power supply. We investigated the possibility of parametric resonance in this system, showing that the excitation mechanism can generate chaotic response. Numerical experiments are carried out to present the existence of several types of regular and chaotic attractors. For the first time powers (power of the motor, power consumed by the damping force under fluid free surface oscillations, and a total power) are calculated, investigated, and shown for different regimes, regular and chaotic ones for parametric resonance interactions.
Failure Diagnosis of a Gear Box by Recurrences
Authors: Syta Arkadiusz , Jonak Józef , Jedliński Łukasz , Litak Grzegorz
Published: July 2012

The recurrence analysis method is used in the mechanical diagnosis of a gear transmission system using time domain data. The recurrence is a natural behavior of a periodic motion system, which tells the state of the system, after running some time, and will approach a certain past state. In this paper, some statistical parameters of recurrence qualification analysis are extensively evaluated for the use of mechanical diagnosis, based on fairly short acceleration time series; recurrence results are compared with those obtained from Fourier analysis, and the identification procedures for the failure gear transmission by recurrences is also presented. It is found that, using only fairly short time series, some statistical parameters in quantification recurrence analysis can give clear-cut distinction between a healthy and damaged state.
Nondestructive Evaluation of Composite Material Damage Using Vibration Reciprocity Measurements
Authors: Zwink Brandon R.
Published: July 2012

Maintenance personnel in the U.S. military are interested in developing methods of damage detection for composite materials that are field expedient and less dependent on the operator’s experience than the current methods. A vibration-based method was developed for detecting damage in composite materials based on a measurement of the nonlinear forced response that damaged materials are assumed to exhibit. A damage feature was extracted for a structural component by quantifying the degree to which the reciprocity between two input-output structural paths fail due to the nonlinearities associated with damage. A dynamic nonlinear theoretical model was used to develop a better understanding of why reciprocity fails for networks of nonlinear components. Experimental results were obtained from carbon fiber composite specimens subjected to various levels of damage. It was determined that reciprocity measurements were capable of identifying damage due to impact energies of 10.8 N·m; however, the method was not capable of discerning damage that was not directly beneath the sensor locations. The levels of damage that could be consistently detected using the new methodology could be discovered through a close visual inspection. In comparison to currently employed methods of damage detection, the proposed methodology is less subjective but also less sensitive to damage. More development work will be required to propose this technology as a replacement for current methods such as ultrasound and tap testing.
Application of the Nondimensional Dynamic Influence Function Method for Free Vibration Analysis of Arbitrarily Shaped Membranes
Authors: Kang Sang Wook , Atluri Satya N. , Kim Sang-Hyun
Published: July 2012

A new formulation for the NDIF method (the nondimensional dynamic influence function method) is introduced to efficiently extract eigenvalues and mode shapes of arbitrarily shaped, homogeneous membranes with the fixed boundary. The NDIF method, which was developed by the authors for the accurate free vibration analysis of arbitrarily shaped membranes and plates including acoustic cavities, has the feature that it yields highly accurate solutions compared with other analytical methods or numerical methods (the finite element method and the boundary element method). However, the NDIF method has the weak point that the system matrix of the method is not independent of the frequency parameter and as a result the method needs the inefficient procedure of searching eigenvalues by plotting the values of the determinant of the system matrix in the frequency parameter range of interest. An improved formulation presented in the paper does not require the above-mentioned inefficient procedure because a newly developed system matrix is independent of the frequency parameter. Finally, the validity of the proposed method is shown in several case studies, which indicate that eigenvalues and mode shapes obtained by the proposed method are very accurate compared to those calculated by exact, analytica, or numerical methods.
Probabilistic and Interval Analyses Contrasted in Impact Buckling of a Clamped Column
Authors: Elishakoff Isaac , Verhaeghe Wim , Moens David
Published: July 2012

In this study we contrast two competing methodologies for the impact buckling of a column that is clamped at both ends. The initial imperfection is postulated to be co-configurational with the fundamental mode shape of the column without the axial loading. A solution is also furnished for the case when the initial imperfection is proportional to the Filonenko-Borodich “cosinusoidal polynomial”. Probabilistic and interval analyses are conducted for each case; these are contrasted on some representative numerical data.
Comparison of Strain-Gage and Fiber-Optic Goniometry for Measuring Knee Kinematics During Activities of Daily Living and Exercise
Authors: Mohamed Abeer A. , Baba Jennifer , Beyea James , Landry John , Sexton Andrew , McGibbon Chris A.
Published: July 2012

There is increasing interest in wearable sensor technology as a tool for rehabilitation applications in community or home environments. Recent studies have focused on evaluating inertial based sensing (accelerometers, gyroscopes, etc.) that provide only indirect measures of joint motion. Measurement of joint kinematics using flexible goniometry is more direct, and still popular in laboratory environments, but has received little attention as a potential tool for wearable systems. The aim of this study was to compare two goniometric devices: a traditional strain-gauge flexible goniometer, and a fiberoptic flexible goniometer, for measuring dynamic knee flexion/extension angles during activity of daily living: chair rise, and gait; and exercise: deep knee bends, against joint angles computed from a “gold standard” Vicon motion tracking system. Six young adults were recruited to perform the above activities in the lab while wearing a goniometer on each knee, and reflective markers for motion tracking. Kinematic data were collected simultaneously from the goniometers (one on each leg) and the motion tracking system (both legs). The results indicate that both goniometers were within 2–5 degrees of the Vicon angles for gait and chair rise. For some deep knee bend trials, disagreement with Vicon angles exceeded ten degrees for both devices. We conclude that both goniometers can record ADL knee movement faithfully and accurately, but should be carefully considered when high (>120 deg) knee flexion angles are required.
A Model of Strain-Dependent Glomerular Basement Membrane Maintenance and Its Potential Ramifications in Health and Disease
Authors: Barocas Victor H. , Dorfman Kevin D. , Segal Yoav
Published: July 2012

A model is developed and analyzed for type IV collagen turnover in the kidney glomerular basement membrane (GBM), which is the primary structural element in the glomerular capillary wall. The model incorporates strain dependence in both deposition and removal of the GBM, leading to an equilibrium tissue strain at which deposition and removal are balanced. The GBM thickening decreases tissue strain per unit of transcapillary pressure drop according to the law of Laplace, but increases the transcapillary pressure drop required to maintain glomerular filtration. The model results are in agreement with the observed GBM alterations in Alport syndrome and thin basement membrane disease, and the model-predicted linear relation between the inverse capillary radius and inverse capillary thickness at equilibrium is consistent with published data on different mammals. In addition, the model predicts a minimum achievable strain in the GBM based on the geometry, properties, and mechanical environment; that is, an infinitely thick GBM would still experience a finite strain. Although the model assumptions would be invalid for an extremely thick GBM, the minimum achievable strain could be significant in diseases, such as Alport syndrome, characterized by focal GBM thickening. Finally, an examination of reasonable values for the model parameters suggests that the oncotic pressure drop—the osmotic pressure difference between the plasma and the filtrate due to large molecules—plays an important role in setting the GBM strain and, thus, leakage of protein into the urine may be protective against some GBM damage.
Lattice-Misfit Stresses in a Circular Bi-Material Gallium-Nitride Assembly
Authors: Suhir E.
Published: July 2012

A simple and physically meaningful analytical (“mathematical”) predictive model is developed using two-dimensional (plane-stress) theory-of-elasticity approach (TEA) for the evaluation of the effect of the circular configuration of the substrate (wafer) on the elastic lattice-misfit (mismatch) stresses (LMS) in a semiconductor and particularly in a gallium nitride (GaN) film grown on such a substrate. The addressed stresses include (1) the interfacial shearing stress supposedly responsible for the occurrence and growth of dislocations, for possible delaminations, and for the cohesive strength of the intermediate strain buffering material, if any, as well as (2) normal radial and circumferential (tangential) stresses acting in the film cross-sections and responsible for the short- and long-term strength (fracture toughness) of the film. The TEA results are compared with the formulas obtained using strength-of-materials approach (SMA). This approach considers, instead of the actual circular substrate, an elongated bi-material rectangular strip of unit width and of finite length equal to the wafer diameter. The numerical example is carried out, as an illustration, for a GaN film grown on a silicon carbide (SiC) substrate. It is concluded that the SMA model is acceptable for understanding the physics of the state of stress and for the prediction of the normal stresses in the major midportion of the assembly. The SMA model underestimates, however, the maximum interfacial shearing stress at the assembly periphery and, because of the very nature of the SMA, is unable to address the circumferential stress. The developed TEA model can be used, along with the author's earlier publications and the (traditional and routine) finite-element analyses (FEA), to assess the merits and shortcomings of a particular semiconductor crystal growth (SCG) technology, as far as the level of the expected LMS are concerned, before the actual experimentation and/or fabrication is decided upon and conducted.
Status and prospects of Al2O3-based surface passivation schemes for silicon solar cells
Authors: Dingemans G. , Kessels W. M. M.
Published: July 2012

The reduction in electronic recombination losses by the passivation of silicon surfaces is a critical enabler for high-efficiency solar cells. In 2006, aluminum oxide (Al2O3) nanolayers synthesized by atomic layer deposition (ALD) emerged as a novel solution for the passivation of p- and n-type crystalline Si (c-Si) surfaces. Today, high efficiencies have been realized by the implementation of ultrathin Al2O3 films in laboratory-type and industrial solar cells. This article reviews and summarizes recent work concerning Al2O3 thin films in the context of Si photovoltaics. Topics range from fundamental aspects related to material, interface, and passivation properties to synthesis methods and the implementation of the films in solar cells. Al2O3 uniquely features a combination of field-effect passivation by negative fixed charges, a low interface defect density, an adequate stability during processing, and the ability to use ultrathin films down to a few nanometers in thickness. Although various methods can be used to synthesize Al2O3, this review focuses on ALD—a new technology in the field of c-Si photovoltaics. The authors discuss how the unique features of ALD can be exploited for interface engineering and tailoring the properties of nanolayer surface passivation schemes while also addressing its compatibility with high-throughput manufacturing. The recent progress achieved in the field of surface passivation allows for higher efficiencies of industrial solar cells, which is critical for realizing lower-cost solar electricity in the near future.
Shear-Activated Nanotherapeutics for Drug Targeting to Obstructed Blood Vessels
Authors: Korin Netanel , Kanapathipillai Mathumai , Matthews Benjamin D. , Crescente Marilena , Brill Alexander , Mammoto Tadanori , Ghosh Kaustabh , Jurek Samuel , Bencherif Sidi A. , Bhatta Deen , Coskun Ahmet U. , Feldman Charles L. , Wagner Denisa D. , Ingber Donald E.
Published: July 2012

Bio-Inspired Drug Delivery

Noting that platelets naturally migrate to narrowed blood vessels characterized by high fluid shear stress,

Korin
et al.

(p.
738
, published online 5 July; see the Perspective by

Lavik and Ustin

) developed a nanoparticle-based therapeutic that uses a similar targeting mechanism to deliver a drug to vessels obstructed by blood clots. Aggregates of nanoparticles coated with the clot-dissolving drug tPA (tissue plasminogen activator) were designed to fall apart and release the drug only when encountering high fluid shear stress. In preclinical models, the bio-inspired therapeutic dissolved clots and restored normal blood flow at lower doses than free tPA, suggesting that this localized delivery system may help reduce the risk of side effects such as excessive bleeding.
Challenges to India's Pharmaceutical Patent Laws
Authors: Sampat Bhaven N. , Shadlen Kenneth C. , Amin Tahir M.
Published: July 2012

An Indian Supreme Court decision about variants of existing compounds could affect access to affordable drugs.
Cytomegalovirus oesophagitis following treatment with fludarabine for refractory lymphoplasmacytic lymphoma
Authors: Pyatt Nicola , Mitra Subir
Published: July 2012

A 64-year-old man with a 2-week history of fatigue and fever presented to the medical admissions unit. He had a background of lymphoplasmacytic lymphoma and had recently completed a course of fludarabine-based chemotherapy. CT of the abdomen demonstrated an increase in spleen size and it was thought that his fevers were most likely due to disease recurrence or high-grade transformation. A bone marrow trephine was organised, which showed no evidence of lymphoma and positron emission tomography-CT demonstrated an area of increased avidity at the gastro-oesophageal junction. An oesophagogastroduodenoscopy was recommended, which revealed ulceration within the oesophagus and stomach. Biopsy of the lesions and immunohistochemistry confirmed a diagnosis of cytomegalovirus oesophagitis. He was treated with intravenous ganciclovir followed by oral valganciclovir for a total of 3 weeks. His fever resolved and he was discharged home approximately 8 weeks after he first presented.
Monitoring community mobilisation and organisational capacity among high-risk groups in a large-scale HIV prevention programme in India: selected findings using a Community Ownership and Preparedness Index
Authors: Narayanan Pradeep , Moulasha K , Wheeler Tisha , Baer James , Bharadwaj Sowmyaa , Ramanathan T V , Thomas Tom
Published: July 2012

Background

In a participatory approach to health and development interventions, defining and measuring community mobilisation is important, but it is challenging to do this effectively, especially at scale.

Methods

A cross-sectional, participatory monitoring tool was administered in 2008–2009 and 2009–2010 across a representative sample of 25 community-based groups (CBGs) formed under the Avahan India AIDS Initiative, to assess their progress in mobilisation, and to inform efforts to strengthen the groups and make them sustainable. The survey used a weighted index to capture both qualitative and quantitative data in numeric form. The index permitted broad, as well as highly detailed, analysis of community mobilisation, relevant at the level of individual groups, as well as state-wide and across the whole programme.

Results

The survey demonstrated that leadership and programme management were the strongest areas among the CBGs, confirming the programme's investment in these areas. Discussion of the Round 1 results led to efforts to strengthen governance and democratic decision making in the groups, and progress was reflected in the Round 2 survey results. CBG engagement with state authorities to gain rights and entitlements and securing the long-term financial stability of groups remain a challenge.

Conclusion

The survey has proven useful for informing the managers of programmes about what is happening on the ground, and it has opened spaces for discussion within community groups about the nature of leadership, decision making and their goals, which is leading to accelerated progress. The tool provided useful data to manage community mobilisation in Avahan.
DECIDABILITY, UNDECIDABILITY, AND GÖDEL'S INCOMPLETENESS IN RELATIVITY THEORIES
Authors: ANDRÉKA HAJNAL , MADARÁSZ JUDIT , NÉMETI ISTVÁN
Published: July 2012

In this paper we investigate the logical decidability and undecidability properties of relativity theories. If we include into our theory the whole theory of the reals, then relativity theory still can be decidable. However, if we actually assume the structure of the quantities in our models to be the reals, or at least to be Archimedean, then we get possible predictions in the language of relativity theory which are independent of ZF set theory.
DETERMINISTIC SAMPLE SORT FOR GPUS
Authors: DEHNE FRANK , ZABOLI HAMIDREZA
Published: July 2012

We demonstrate that parallel deterministic sample sort for many-core GPUs (GPU BUCKET SORT) is not only considerably faster than the best comparison-based sorting algorithm for GPUs (THRUST MERGE [Satish et.al., Proc. IPDPS 2009]) but also as fast as randomized sample sort for GPUs (GPU SAMPLE SORT [Leischner et.al., Proc. IPDPS 2010]). However, deterministic sample sort has the advantage that bucket sizes are guaranteed and therefore its running time does not have the input data dependent fluctuations that can occur for randomized sample sort.
${\mathcal N} = 4$ SUPERSYMMETRIC QUANTUM MECHANICS AND HARMONICS
Authors: IVANOV EVGENY
Published: July 2012

This is an overview of applications of the harmonic variables in [Formula: see text] supersymmetric mechanics, with focusing on some latest results.
How to Reform the Credit-Rating Process to Support a Sustainable Revival of Private-Label Securitization
Authors: Herring Richard , Kane Edward J.
Published: July 2012

US product-liability laws unwisely treat credit-rating organizations (CROs) as if they produce opinions rather than empirically-based economic research. In principle, trained professionals gather time-varying information ("financial news") and analyze it statistically to reduce it to a single dimension, allegedly for the benefit of investors, which, in turn, enables issuers to finance themselves at lower cost. In practice, the issuer-pays business model currently used for funding the production and distribution of ratings information creates an incentive to favor high-volume issuers by over-rating private-label securitizations. While the Dodd–Frank Act intensifies SEC oversight of CRO activity, the SEC has a history of being captured by regulatory clients. We argue that the fundamental solution is to create accountability in the ratings process so that private label securitizations can play a constructive role in the provision of credit and we go on to offer some conjectures about how this could be done.
Equity Home Bias and the Euro
Authors: Foad Hisham S.
Published: July 2012

This paper examines explanations for the equity home bias puzzle by utilizing the introduction of the euro in 1999 as a natural experiment. The introduction of the euro and the coordination of monetary policy across the Euro Area (EA) allows for a closer examination of this puzzle. Optimal foreign equity shares are derived from a version of the CAP-M and then empirically tested using detailed data from the IMF's Coordinated Portfolio Investment Survey covering the foreign equity holdings of 23 countries for the years 1997 and 2001–2004. While equity home bias has fallen worldwide over this period, by far the sharpest drop has been for intra-EA equity holdings with home bias falling from 68% to 29% between the pre and post-euro periods. Several explanations for this drop are tested, with the reduction in information asymmetries emerging as the most promising candidate.
Persistence of Beliefs in an Investment Experiment
Authors: Ko K. Jeremy , Huang Zhijian (James)
Published: July 2012

A number of behavioral finance theories posit that investors adhere to prior beliefs in spite of new information. This paper reports the results of an investment experiment which shows that subjects' inferences are biased by their prior beliefs in a manner that depends on investment outcomes. Specifically, survey responses and investment behavior indicate that subjects' perception of new information was more positively biased for their previously favored assets when incurring losses than gains. This asymmetric bias may help explain empirical patterns such as loser momentum and suggests modifications to models of belief persistence in markets.
Optical Second-Harmonic Generation in Hydrogenated Amorphous Silicon Single- and Double-Junction Solar Cells
Authors: Ou-Yang Wei , Manaka Takaaki , Naitou Seiichi , Kunitomo Kyoji , Iwamoto Mitsumasa
Published: July 2012

Using an electric-field-induced optical second-harmonic generation (EFISHG) technique, we studied the SHG from hydrogenated amorphous silicon (a-Si:H) solar cells. The SHG signal originating from a-Si interface is independent of external bias voltage (V
ex), whereas that generated from the intrinsic layer is strongly dependent on V
ex. The difference in the tendency of bias-dependent EFISHG intensity between a-Si single-junction solar cells and a-Si/microcrystalline silicon (µc-Si) double-junction (tandem) solar cells indicates the presence of another origin of the EFISHG generation in the tandem cells. That is, the p–n junction formed between the p-type µc-Si:H and n-type a-Si:H. These findings indicate that the EFISHG technique is available for characterizing the local electric field in a-Si solar cells.
Rapid Reversible Degradation of Silicon Thin Films by a Treatment in Water
Authors: Turan Elif , Yilmaz Gokhan , Smirnov Vladimir , Finger Friedhelm , Günes Mehmet
Published: July 2012

Metastability effects in amorphous and microcrystalline silicon thin films induced by exposure to atmospheric gases and water are investigated. A simple procedure is described which allows studying such effects in a reproducible and reliable manner on a short time scale. The method is applied to thin film silicon materials with different structure composition ranging from amorphous to highly crystalline. It is shown that the materials can be brought back into a well defined state even after pro-longed and repeated degradation cycles.
Electrical and Structural Properties of 0.98(Na0.5K0.5)NbO3–0.02Ba(Zr0.52Ti0.48)O3 Ceramics with CuO Content
Authors: Lee Seung-Hwan , Lee Sung-Gap , Lee Young-Hie
Published: July 2012

In this study, lead-free 0.98(Na0.5K0.5)NbO3–0.02Ba(Zr0.52Ti0.48)O3+x mol % CuO (x = 0, 0.5, 1.0, 1.5, or 2.0) ceramics were fabricated. Moreover, the electrical and structural properties of the samples were also investigated. With 1.0 mol % CuO content, the 0.98(Na0.5K0.5)NbO3–0.02Ba(Zr0.52Ti0.48)O3 (abbreviated as 0.98NKN–0.02BZT) ceramic had the maximum electromechanical coupling coefficient (k
p) = 0.48, piezoelectric constant (d
33) = 241 pC/N, and dielectric constant = 1577, respectively, at x=1.0 at room temperature.
Suppression of IL-8 production in gastric epithelial cells by MUC1 mucin and peroxisome proliferator-associated receptor-γ
Authors: Park Yong Sung , Guang Wei , Blanchard Thomas G. , Chul Kim K. , Lillehoj Erik P.
Published: July 2012

MUC1 is a membrane-tethered mucin expressed on the apical surface of epithelial cells. Our previous report (Guang W, Ding H, Czinn SJ, Kim KC, Blanchard TG, Lillehoj EP. J Biol Chem 285: 20547–20557, 2010) demonstrated that expression of MUC1 in AGS gastric epithelial cells limits Helicobacter pylori infection and reduces bacterial-driven IL-8 production. In this study, we identified the peroxisome proliferator-associated receptor-γ (PPARγ) upstream of MUC1 in the anti-inflammatory pathway suppressing H. pylori- and phorbol 12-myristate 13-acetate (PMA)-stimulated IL-8 production. Treatment of AGS cells with H. pylori or PMA increased IL-8 levels in cell culture supernatants compared with cells treated with the respective vehicle controls. Prior small interfering (si)RNA-induced MUC1 silencing further increased H. pylori - and PMA-stimulated IL-8 levels compared with a negative control siRNA. MUC1-expressing AGS cells pretreated with the PPARγ agonist troglitazone (TGN) had reduced H. pylori - and PMA-stimulated IL-8 levels compared with cells treated with H. pylori or PMA alone. However, following MUC1 siRNA knockdown, no differences in IL-8 levels were seen between TGN/ H. pylori and H. pylori -only cells or between TGN/PMA and PMA-only cells. Finally, TGN-treated AGS cells had increased Muc1 promoter activity, as measured using a Muc1-luciferase reporter gene, and greater MUC1 protein levels by Western blot analysis, compared with vehicle controls. These results support the hypothesis that PPARγ stimulates MUC1 expression by AGS cells, thereby attenuating H. pylori - and PMA-induced IL-8 production.
Reproducibility of swallow-induced cortical BOLD positive and negative fMRI activity
Authors: Babaei Arash , Ward B. Douglas , Ahmad Shahryar , Patel Anna , Nencka Andrew , Li Shi-Jiang , Hyde James , Shaker Reza
Published: July 2012

Functional MRI (fMRI) studies have demonstrated that a number of brain regions (cingulate, insula, prefrontal, and sensory/motor cortices) display blood oxygen level-dependent (BOLD) positive activity during swallow. Negative BOLD activations and reproducibility of these activations have not been systematically studied. The aim of our study was to investigate the reproducibility of swallow-related cortical positive and negative BOLD activity across different fMRI sessions. We studied 16 healthy volunteers utilizing an fMRI event-related analysis. Individual analysis using a general linear model was used to remove undesirable signal changes correlated with motion, white matter, and cerebrospinal fluid. The group analysis used a mixed-effects multilevel model to identify active cortical regions. The volume and magnitude of a BOLD signal within each cluster was compared between the two study sessions. All subjects showed significant clustered BOLD activity within the known areas of cortical swallowing network across both sessions. The cross-correlation coefficient of percent fMRI signal change and the number of activated voxels across both positive and negative BOLD networks were similar between the two studies ( r ≥ 0.87, P < 0.0001). Swallow-associated negative BOLD activity was comparable to the well-defined “default-mode” network, and positive BOLD activity had noticeable overlap with the previously described “task-positive” network. Swallow activates two parallel cortical networks. These include a positive and a negative BOLD network, respectively, correlated and anticorrelated with swallow stimulus. Group cortical activity maps, as well as extent and amplitude of activity induced by volitional swallowing in the cortical swallowing network, are reproducible between study sessions.
The modulatory influence of end-point controllability on decisions between actions
Authors: Cos Ignasi , Medleg Farid , Cisek Paul
Published: July 2012

Recent work has shown that human subjects are able to predict the biomechanical ease of potential reaching movements and use these predictions to influence their choices. Here, we examined how reach decisions are influenced by specific biomechanical factors related to the control of end-point stability, such as aiming accuracy or stopping control. Human subjects made free choices between two potential reaching movements that varied in terms of path distance and biomechanical cost in four separate blocks that additionally varied two constraints: the width of the targets (narrow or wide) and the requirement of stopping in them. When movements were unconstrained (very wide targets and no requirement of stopping), subjects' choices were strongly biased toward directions aligned with the direction of maximal mobility. However, as the movements became progressively constrained, factors related to the control of the end point gained relevance, thus reducing this bias. This demonstrates that, before movement onset, constraints such as stopping and aiming participate in a remarkably adaptive and flexible action selection process that trades off the advantage of moving along directions of maximal mobility for unconstrained movements against exploiting biomechanical anisotropies to facilitate control of end-point stability whenever the movement constraints require it. These results support a view of decision making between motor actions as a highly context-dependent gradual process in which the subjective desirability of potential actions is influenced by their dynamic properties in relation to the intrinsic properties of the motor apparatus.
Intracellular Na+and metabolic modulation of Na/K pump and excitability in the rat suprachiasmatic nucleus neurons
Authors: Wang Yi-Chi , Yang Jyh-Jeen , Huang Rong-Chi
Published: July 2012

Na/K pump activity and metabolic rate are both higher during the day in the suprachiasmatic nucleus (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na+and energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of extracellular K+to block the Na/K pump excited SCN neurons to fire at higher rates and return to normal K+to reactivate the pump produced rebound hyperpolarization to inhibit firing. In the presence of tetrodotoxin to block the action potentials, both zero K+-induced depolarization and rebound hyperpolarization were blocked by the cardiac glycoside strophanthidin. Ratiometric Na+imaging with a Na+-sensitive fluorescent dye indicated saturating accumulation of intracellular Na+in response to pump blockade with zero K+. The Na+ionophore monensin also induced Na+loading and hyperpolarized the membrane potential, with the hyperpolarizing effect of monensin abolished in zero Na+or by pump blockade. Conversely, Na+depletion with Na+-free pipette solution depolarized membrane potential but retained residual Na/K pump activity. Cyanide inhibition of oxidative phosphorylation blocked the Na/K pump to depolarize resting potential and increase spontaneous firing in most cells, and to raise intracellular Na+levels in all cells. Nonetheless, the Na/K pump was incompletely blocked by cyanide but completely blocked by iodoacetate to inhibit glycolysis, indicating the involvement of both oxidative phosphorylation and glycolysis in fueling the Na/K pump. Together, the results indicate the importance of intracellular Na+and energy metabolism in regulating Na/K pump activity as well as neuronal excitability in the SCN neurons.
Adaptive coding is constrained to midline locations in a spatial listening task
Authors: Maier J. K. , Hehrmann P. , Harper N. S. , Klump G. M. , Pressnitzer D. , McAlpine D.
Published: July 2012

Many neurons adapt their spike output to accommodate the prevailing sensory environment. Although such adaptation is thought to improve coding of relevant stimulus features, the relationship between adaptation at the neural and behavioral levels remains to be established. Here we describe improved discrimination performance for an auditory spatial cue (interaural time differences, ITDs) following adaptation to stimulus statistics. Physiological recordings in the midbrain of anesthetized guinea pigs and measurement of discrimination performance in humans both demonstrate improved coding of the most prevalent ITDs in a distribution, but with highest accuracy maintained for ITDs corresponding to frontal locations, suggesting the existence of a fovea for auditory space. A biologically plausible model accounting for the physiological data suggests that neural tuning is stabilized by inhibition to maintain high discriminability for frontal locations. The data support the notion that adaptive coding in the midbrain is a key element of behaviorally efficient sound localization in dynamic acoustic environments.
Strong Convergence of Hybrid Algorithm for Asymptotically Nonexpansive Mappings in Hilbert Spaces
Authors: Su Juguo , Tang Yuchao , Liu Liwei
Published: July 2012

The hybrid algorithms for constructing fixed points of nonlinear mappings have been studied extensively in recent years. The advantage of this methods is that one can prove strong convergence theorems while the traditional iteration methods just have weak convergence. In this paper, we propose two types of hybrid algorithm to find a common fixed point of a finite family of asymptotically nonexpansive mappings in Hilbert spaces. One is cyclic Mann′s iteration scheme, and the other is cyclic Halpern′s iteration scheme. We prove the strong convergence theorems for both iteration schemes.
Development of Hepatocellular Carcinoma Associated with Anabolic Androgenic Steroid Abuse in a Young Bodybuilder: A Case Report
Authors: Hardt Aline , Stippel Dirk , Odenthal Margarete , Hölscher Arnulf H. , Dienes Hans-Peter , Drebber Uta
Published: July 2012

Introduction. Many different etiological factors are involved in the development of hepatocellular carcinoma (HCC). We report the case of HCC in a 37-year-old male professional bodybuilder with extensive anabolic androgenic (AAS) steroid abuse.Case Presentation. Because of increasing epigastric and abdominal pain, abdominal ultrasound was performed in a 37-year-old male professional bodybuilder. A hyperechoic lesion in the liver was detected in segment VI. The magnetic resonance imaging showed hepatomegaly and confirmed the lesion, which showed features of a hepatocellular adenoma (HCA). Laboratory values were inconspicuous. After laparoscopic segmentectomy the histological examination revealed HCC.Conclusion. While the development of HCA in the liver by chronic intake of AAS is well known, little is known about the association with HCC. The presented case may indicate aetiological association of chronic intake of AAS and the development of HCC.
Exercise in the Metabolic Syndrome
Authors: Golbidi Saeid , Mesdaghinia Azam , Laher Ismail
Published: July 2012

The metabolic syndrome is a clustering of obesity, diabetes, hyperlipidemia, and hypertension that is occurring in increasing frequency across the global population. Although there is some controversy about its diagnostic criteria, oxidative stress, which is defined as imbalance between the production and inactivation of reactive oxygen species, has a major pathophysiological role in all the components of this disease. Oxidative stress and consequent inflammation induce insulin resistance, which likely links the various components of this disease. We briefly review the role of oxidative stress as a major component of the metabolic syndrome and then discuss the impact of exercise on these pathophysiological pathways. Included in this paper is the effect of exercise in reducing fat-induced inflammation, blood pressure, and improving muscular metabolism.
Exact Matrix Representation of the Transverse Magnetic Multiple Scattering of Obliquely Incident Plane Waves by the Diffraction Grating of Penetrable Cylinders
Authors: Kavaklıoğlu Ömer , Lang Roger Henry
Published: July 2012

“An exact matrix conformation model” associated with the equations describing the exact behavior of the Fourier‐Bessel multiple scattering coefficients of the diffraction grating consisting of an infinite number of infinitely long parallel penetrable circular cylinders, corresponding to the obliquely incident transverse‐magnetic plane waves in “Twersky-Wait-Kavaklıoğlu representation,” originally excogitated in (Kavaklıoğlu, 2000), is acquired, and the exact solution for “the Fourier-Bessel multiple scattering coefficients of the diffraction grating at oblique incidence” is obtained by a matrix inversion procedure.
Nanoenhanced Materials for Reclamation of Mine Lands and Other Degraded Soils: A Review
Authors: Liu Ruiqiang , Lal Rattan
Published: July 2012

Successful mine soil reclamation facilitates ecosystem recovery, minimizes adverse environmental impacts, creates additional lands for agricultural or forestry uses, and enhances the carbon (C) sequestration. Nanoparticles with extremely high reactivity and deliverability can be applied as amendments to improve soil quality, mitigate soil contaminations, ensure safe land–application of the conventional amendment materials (e.g., manures and biosolids), and enhance soil erosion control. However, there is no report on using nanoenhanced materials for mine soil reclamation. Through reviewing the up-to-date research results on using environment-friendly nanoparticles for agricultural soil quality improvement and for contaminated soil remediation, this paper synthesizes that these nanomaterials with high potentials for mine soil reclamation include zeolites, zero-valent iron nanoparticles, iron oxide nanoparticles, phosphate-based nanoparticles, iron sulfide nanoparticles and C nanotubes. Transport of these particles in the environment and their possible ecotoxicological effects are also discussed. Additionally, this article proposes a practical and economical approach to applying nanotechnology for mine soil reclamation: adding small amounts of nanoparticles to the conventional soil amendment materials and then applying the mixtures for soil quality improvements. Hence the cost of using nanoparticles is reduced and the benefits of both nanoparticles and the conventional amendment materials are harnessed.
Adolescent Metabolic Syndrome Risk Is Increased with Higher Infancy Weight Gain and Decreased with Longer Breast Feeding
Authors: Khuc Kim , Blanco Estela , Burrows Raquel , Reyes Marcela , Castillo Marcela , Lozoff Betsy , Gahagan Sheila
Published: July 2012

Background. Prevalence of the metabolic syndrome is increasing in pediatric age groups worldwide. Meeting the criteria for the metabolic syndrome puts children at risk for later cardiovascular and metabolic disease.Methods. Using linear regression, we examined the association between infant weight gain from birth to 3 months and risk for the metabolic syndrome among 16- to 17-year-old Chilean adolescents (n=357), accounting for the extent of breastfeeding in infancy and known covariates including gender, birth weight, and socioeconomic status.Results. Participants were approximately half male (51%), born at 40 weeks of gestation weighing 3.5 kg, and 48% were exclusively breastfed for≥90days. Factors independently associated with increased risk of metabolic syndrome in adolescence were faster weight gain in the first 3 months of life (B=0.16,P<0.05) and male gender (B=0.24,P<0.05). Breastfeeding as the sole source of milk for≥90days was associated with significantly decreased risk of metabolic syndrome (B=−0.16).Conclusion. This study adds to current knowledge about early infant growth and breastfeeding and their long-term health effects.
Pathogenicity ofTreponema denticolaWild-Type and Mutant Strain Tested by an Active Mode of Periodontal Infection Using Microinjection
Authors: Izard Jacques , Sasaki Hajime , Kent Ralph
Published: July 2012

The available passive mode of periodontal infections in mice requires high efficiency of bacterial attachment and invasiveness and is not always suitable to test the pathogenicity of genetically engineered mutant strains. We developed an active mode of oral infection, using microinjection in the marginal gingiva of mice, to test the pathogenicity of a genetically engineeredTreponema denticolamutant strain deficient in intermediate-like filaments, compared to the wild-type strain. This targeted mode of infection inoculates the bacterial strain to be tested directly at a lesion site (needle entry point) located at the future periodontal lesion site. The efficiency ofT. denticolawild-type strain to elicit bone loss contrasted with the lack of pathogenicity of the intermediate-like filament deficient mutant strain in comparison to the sham infection. The periodontal microinjection oral model in mice can be used for a variety of applications complementary to the passive mode of periodontal infection in context of pathogenicity testing.