bluuebunny/crossref_metadata_2025 huggingface dataset:
DIVERSITY OF TRAVELING WAVE SOLUTIONS IN DELAYED CELLULAR NEURAL NETWORKS
Authors: HSU CHENG-HSIUNG , LI CHUN-HSIEN , YANG SUH-YUH
Published: February 2009

This work investigates the diversity of traveling wave solutions for a class of delayed cellular neural networks on the one-dimensional integer lattice ℤ1. The dynamics of a given cell is characterized by instantaneous self-feedback and neighborhood interaction with distributed delay due to, for example, finite switching speed and finite velocity of signal transmission. Applying the monotone iteration scheme, we can deduce the existence of monotonic traveling wave solutions provided the templates satisfy the so-called quasi-monotonicity condition. We then consider two special cases of the delayed cellular neural network in which each cell interacts only with either the nearest m left neighbors or the nearest m right neighbors. For the former case, we can directly figure out the analytic solution in an explicit form by the method of step with the help of the characteristic function and then prove that, in addition to the existence of monotonic traveling wave solutions, for certain templates there exist nonmonotonic traveling wave solutions such as camel-like waves with many critical points. For the latter case, employing the comparison arguments repeatedly, we can clarify the deformation of traveling wave solutions with respect to the wave speed. More specifically, we can describe the transition of profiles from monotonicity, damped oscillation, periodicity, unboundedness and back to monotonicity as the wave speed is varied. Some numerical results are also given to demonstrate the theoretical analysis.
NOTE ON STRANGE NONFRACTAL ATTRACTORS
Authors: DEL RIO E. , DONOSO J. M.
Published: February 2009

We present a case of a strange nonchaotic attractor (SNA) which is also nonfractal and continuous. This provides a counterexample to the widely extended assumption about the intrinsic fractal nature of any SNA. We also show that the most useful techniques to characterize the SNA fail for this case.
STRANGE ATTRACTORS, KINEMATIC TRAJECTORIES AND SYNCHRONIZATION
Authors: FORTUNA LUIGI , FRASCA MATTIA , CAMERANO CRISTOFORO
Published: February 2009

In this communication the emergent behavior of clusters of robots with chaotic kinematics attractors is shown. Even if the aim of the research started from the study of the cooperative behavior of inspection robots, the reported results (including also the role of chaotic synchronization in the generation of the kinematics trajectory), show new aesthetic features of the motion in mechanical control systems.
THE CHEN SYSTEM HAVING AN INVARIANT ALGEBRAIC SURFACE
Authors: CAO JINLONG , CHEN CHENG , ZHANG XIANG
Published: February 2009

In this paper, we characterize the dynamics of the Chen system ẋ = a(y - x), ẏ = (c - a)x - xz + cy, ż = xy - bz which has an invariant algebraic surface.
BOOLEAN NETWORKS WITH MEMORY
Authors: ALONSO-SANZ RAMÓN , BULL LARRY
Published: February 2009

In standard Boolean Networks (BN) the new state of a cell depends upon the neighborhood configuration only at the preceding time step. The effect of implementing memory of different types in cells of BN with different degrees of random rewiring is studied in this article.
THERMAL SOLITONS AND SOLECTRONS IN 1D ANHARMONIC LATTICES UP TO PHYSIOLOGICAL TEMPERATURES
Authors: VELARDE M. G. , EBELING W. , CHETVERIKOV A. P.
Published: February 2009

We study the thermal excitation of solitons in 1D Toda–Morse lattices in a wide range of temperatures from zero up to physiological level (about 300 K) and their influence on added excess electrons moving on the lattice. The lattice units are treated by classical Langevin equations. The electron distributions are in a first estimate represented by equilibrium adiabatic distributions in the actual fields. Further, the electron dynamics is modeled in the framework of the tight-binding approximation including on-site energy shifts due to electron-lattice coupling and stochastic hopping between the sites. We calculate the electron distributions and discuss the excitations of solectron type (electron-soliton dynamic bound states) and estimate their life times.
OZONE SENSING PROPERTIES OF THERMALLY EVAPORATED In2O3-BASED THIN FILMS
Authors: ARSHAK K. , HICKEY G. , FORDE E. , HARRIS J.
Published: February 2009

Ozone sensing properties of mixed oxides of In 2 O 3, ZnO , and SnO 2 in the form of thin films are explored. Exposure to ozone causes defects in the materials, and subsequently causes changes in the materials properties. In this work, a cost-effective, room temperature, real-time ozone monitoring device has been developed. The fabricated sensors are capable of detecting threshold ozone safety levels proposed by the World Health Organization (WHO) while operating at room temperature. Room temperature operation offers many advantages over high temperature operation, such as reduced power consumption, reduced fabrication costs, and ease of implementation into portable devices, such as laptops and mobile phones. The fabrication of these sensors was carried out by means of an Edwards E306A Coating System. Various mixtures of In 2 O 3, ZnO , and snO 2 were deposited in a rectangular pattern on top of copper interdigitated electrodes. X-ray Photo Spectroscopy (XPS) analysis showed that there were levels of impurities in the sensor samples, which were dependant on the fabrication process and parameters. XPS analysis also gave a detailed account of the shifts in binding energies of the thin oxide layers. The results presented show that the highest response to environmentally relevant ozone concentrations is achieved with a very thin sensing layer and a high deposition rate. The performance of the sensors has been investigated and compared.
SIMULTANEOUSLY CATALYTIC REMOVAL OF NOx AND SOOT ON RARE EARTH ELEMENT OXIDE LOADED WITH POTASSIUM AND TRANSITION NANOSIZED METAL OXIDES
Authors: JIANG ZHI , ZHANG HAIRONG , WANG ZHONGPENG , CHEN MINGXIA , SHANGGUAN WENFENG
Published: February 2009

The simultaneous catalytic removal of NO x and soot over the rare earth element (REE) oxide-based mixture oxides loaded with potassium and transition nanosized metal oxide (designated as M/K/REE oxide) was investigated by using temperature-programmed reaction (TPR). The influence of the type of REE oxides together with the type and amount of transitional metal oxides on the catalytic removal activity was discussed. K / Nd 2 O 3 was found to be the most active oxide among the REE oxides to simultaneous remove the NO x and soot under lean conditions. Chromium oxide was more active than the other transition metal oxides on enhancing the activity of soot oxidation of Nd 2 O 3 loaded with potassium. The optimum loading level of chromium was about 10 wt%, with ignition temperature at about 237°C and the conversion ratio NO → N 2 about 24.1%. The Mn -loading on K / Nd 2 O 3 resulted in the biggest conversion efficiency of NO to N 2 at about 30.2%. The increasing catalytic reaction of NO x–soot activities is attributed to the formation of complex crystalline phase in the catalyst together with the improving contacting between catalysts and soot.
MEASUREMENT OF AEROSOLS IN ENGINEERED NANOMATERIALS FACTORIES FOR RISK ASSESSMENT
Authors: FUJITANI YUJI , KOBAYASHI TAKAHIRO
Published: February 2009

In relation to potential health risks, there is little available information on exposure to aerosols containing nanometer-size particles in work environments in factories producing engineered nanomaterials. We measured the concentrations and size distributions of particles of nanometer-sized to coarse-sized particles in an engineered carbon nanomaterial factory and a titanium dioxide factory. In addition, particles were collected with a quartz fiber filter in the engineered carbon nanomaterial factory, and their morphology was examined by scanning electron microscopy and their carbon composition was examined with a carbon analyzer. In the carbon nanomaterial factory, the particle number increased to more than 105 cm-3 when a vacuum cleaner was used to clean the inside of the producing device, and the particle number increased for particles with a diameter of about 100 nm compared with the background. This is the only case an increase in particle numbers is observed during this measurement. The emitted particles appear to consist of agglomerates of carbon nanomaterial particles smaller than 100 nm. The major fraction was the EC3 fraction (EC: elemental carbon; combustion at 800°C in a 98:2 He / O 2 atmosphere), which is a minor fraction in diesel engine particulate matter. This suggests that the combustion temperature can be used to differentiate atmospheric particulate matter from engineered carbon material. Personal sampling conducted in addition to stationary measurements in the titanium dioxide factory indicated that stationary measurements can be used to generate representative data on the basis of the particle number but not the particle mass.
THE ECOLOGICAL EFFECTS OF NANOMATERIALS: A FOCUS ON AQUATIC LIFE
Authors: ZICCARDI LINDA , MCARDLE MARGARET , LOWNEY YVETTE
Published: February 2009

This paper provides an overview of current knowledge regarding the aquatic effects of nanomaterials. Aquatic receptors can potentially be exposed to nanoparticles through ingestion, movement across gills, passive transport, and cellular absorption. Our review indicates that the toxicological research on nanomaterials is still relatively narrow. The present research has been targeted primarily at understanding potential effects to humans, and relatively few ecotoxicity studies have been conducted; however, new research is evolving rapidly. The studies that are currently available focus on metal oxide particles, carbon nanotubes, and fullerenes. Aquatic tests have examined the uptake of these nanoparticles by fish and filter feeders, and have provided evidence of toxicity or behavioral changes. Some of these studies conclude that nanoparticles can be taken up by or produce effects in biota, and that dose-response relationships and patterns of relative toxicity among types of particles are emerging. Caution should be used in designing and interpreting studies on nanoparticles, because factors such as the particle medium preparation method, the presence of other chemicals, and particle behavior such as agglomeration can influence exposure and aquatic toxicity. Ultimately, the objectives of this review are to expand our knowledge of the effects of nanomaterials on ecological processes and aquatic receptor populations, as well as help guide future research.
APPLICATION OF NANOSCALE ZERO-VALENT IRON FOR GROUNDWATER REMEDIATION: LABORATORY AND PILOT EXPERIMENTS
Authors: KLIMKOVA STEPANKA , CERNIK MIROSLAV , LACINOVA LENKA , NOSEK JAROSLAV
Published: February 2009

It is known that the reductive effects of zero-valent iron ( Fe 0) and the sorptive capability of iron and its oxides can be used for both the dehalogenation of chlorinated hydrocarbons (CHC), especially of chlorinated ethenes (PCE → TCE → DCE → VC → ethene, ethane), and the removing of heavy metals from groundwater by turning them into a less-soluble form through changes of their oxidation state, or by adsorption. These consequences are being exploited in the construction of iron filling permeable reactive barriers for a longer time.1 The advantages of nanoscale zero-valent iron ( nanoFe 0) over the macroscopic one consist not only in the better reactivity implicit in their greater specific surface area but also in their mobility in rock environment.2,3 Numerous laboratory experiments, especially the batch-agitated experiments, with samples from seven various contaminated localities in Europe have been carried out with the aim to discover the measurement of the reductive effect of the nanoFe 0 on selected contaminants. It was found that the nanoFe 0 can be reliably usable as a reductive reactant for in-situ chemical decontamination of sites polluted by chlorinated ethenes (CEs), or hexa-valent chromium ( Cr VI ). The rate of reductive reaction and the optimal concentrations for the real remediation action were determined. On the basis of these laboratory experiments, the methods for pilot application of nanoFe 0 have been specified. Subsequently the pilot experiments were accomplished in surveyed localities.
DECONTAMINATION OF NITRATES AND NITRITES IN WASTEWATER BY ZERO-VALENT IRON NANOPARTICLES
Authors: LIN KUEN-SONG , CHANG NI-BIN , CHUANG TIEN-DENG
Published: February 2009

The chemical reduction of nitrate or nitrite species by zero-valent iron nanoparticle (ZVIN) in aqueous solution and related reaction kinetics or mechanisms using fine structure characterization were investigated. Experimentally, ZVIN of this study was prepared by borohydride reduction method at room temperature. The morphology of as-synthesized ZVIN shows that the nearly ball and ultrafine particles ranged of 20–50 nm were observed with FE-SEM analysis. The kinetic model of nitrites or nitrates reductive reaction by ZVIN is proposed as a pseudo-first-order kinetic equation. The nitrite and nitrate removal efficiencies using ZVIN were found 65–83% and 51–68%, respectively, based on three different initial concentrations. By using XRD patterns, the quantitative relationship between nitrite and Fe(III) or Fe(II) becomes similar to the one between nitrate and Fe(III) in the ZVIN study. The possible reason is linked with a faster nitrite reduction by ZVIN. In fact, the occurrence of the relative faster nitrite reductive reaction suggested that the passivation of the ZVIN have a significant contribution to iron corrosion. The XANES spectra show that the nitrites or nitrates reduce to N 2 while oxidizing the ZVIN to Fe 2 O 3 or Fe 3 O 4 electrochemically. It is also very clear that decontamination of nitrate or nitrite species in groundwater via the in-situ remediation with a ZVIN permeable reactive barrier would be environmentally attractive.
NANOTECHNOLOGY IN MEDICINE AND HEALTH SCIENCES
Authors: DENKBAŞ EMIR B. , VASEASHTA A.
Published: February 2009

The present investigation is aimed at the biomedical aspects of nanomaterials in medicine and health sciences. Synthesis of nanomaterials can be categorized into three main sections based on their system designation, viz. nanocolloidal systems, surface modification of the biomaterials at molecular level, and nanodevices. An overview of functionalized nanomaterials, devices, and systems in drug and gene delivery, controlled release systems, molecular imaging and diagnostics, cardiac therapy, dental care, orthopedics, and targeted cancer therapy is presented. We further present some preliminary results of our investigation of biodegradable polymeric nanospheres and nanofibers with significant applications in health and medicine.
BIOLOGICAL EFFECT OF INTRANASALLY INSTILLED TITANIUM DIOXIDE NANOPARTICLES ON FEMALE MICE
Authors: WANG JIANGXUE , LI YUFENG , LI WEI , CHEN CHUNYING , LI BAI , ZHAO YULIANG
Published: February 2009

The toxicological effect of TiO 2 nanoparticles with different crystal structure (80 nm for rutile and 155 nm for anatase) on female mice was investigated through intranasal instillation. After exposure for 30 days at the dose of 50 mg/kg body weight, no abnormal activity and mortality were observed with the normally increasing body weight of mice. The coefficients of tissues to body weight also show no obvious difference from the control except the increased coefficient of kidneys in mice exposed to 80 nm TiO 2 nanoparticles. Titanium contents and histopathology examination indicate the no pathological response in the lung was induced by the increased TiO 2 deposition, and the liver, heart, and spleen were not influenced. The severe pathology changes in kidneys suggest that TiO 2 nanoparticles may be excreted out by kidneys via system circulation. However, the serum biochemical parameters were not changed compared with the control, which means no obvious functional impairment induced by the nasal exposure for 30 days. In addition, the higher titanium contents in the brain tissues imply that the translocation and deposition of nanoparticles through intranasal instilling pathway is different from the other routes such as intratracheal inhalation or intratracheal instillation. The influence of deposited nanoparticles on central nervous system needs further investigation and is underway.
CONTEST
Authors: Taylor Alan , Higham Desmond J.
Published: February 2009

Large, sparse networks that describe complex interactions are a common feature across a number of disciplines, giving rise to many challenging matrix computational tasks. Several random graph models have been proposed that capture key properties of real-life networks. These models provide realistic, parametrized matrices for testing linear system and eigenvalue solvers. CONTEST (CONtrollable TEST matrices) is a random network toolbox for MATLAB that implements nine models. The models produce unweighted directed or undirected graphs; that is, symmetric or unsymmetric matrices with elements equal to zero or one. They have one or more parameters that affect features such as sparsity and characteristic pathlength and all can be of arbitrary dimension. Utility functions are supplied for rewiring, adding extra shortcuts and subsampling in order to create further classes of networks. Other utilities convert the adjacency matrices into real-valued coefficient matrices for naturally arising computational tasks that reduce to sparse linear system and eigenvalue problems.
Dynamic Supernodes in Sparse Cholesky Update/Downdate and Triangular Solves
Authors: Davis Timothy A. , Hager William W.
Published: February 2009

The supernodal method for sparse Cholesky factorization represents the factor
L
as a set of supernodes, each consisting of a contiguous set of columns of
L
with identical nonzero pattern. A conventional supernode is stored as a dense submatrix. While this is suitable for sparse Cholesky factorization where the nonzero pattern of
L
does not change, it is not suitable for methods that modify a sparse Cholesky factorization after a low-rank change to
A
(an update/downdate,
Ā = A ± WW
T
). Supernodes merge and split apart during an update/downdate. Dynamic supernodes are introduced which allow a sparse Cholesky update/downdate to obtain performance competitive with conventional supernodal methods. A dynamic supernodal solver is shown to exceed the performance of the conventional (BLAS-based) supernodal method for solving triangular systems. These methods are incorporated into CHOLMOD, a sparse Cholesky factorization and update/downdate package which forms the basis of x = A\b MATLAB when A is sparse and symmetric positive definite.
Modified gauss algorithm for matrices with symbolic entries
Authors: Fuchssteiner Benno
Published: February 2009

We propose a modification of the usual algorithms for Gaussian elimination, determination of minors and computation of determinants in case of matrices with symbolic data (polynomials, rational functions, general algebraic structures and the like). The proposed modification improves on the Sasaki-Murao algorithm. The new algorithm aims at improving efficiency for a general class algebraic data like polynomials with non exact coefficients, algebraic structures with zero divisors, rational functions and general functions in several variables. The main difference to other approaches is that we replace the diagonal elements not at the beginning of the algorithm but then when they are taken as a pivot elements (independent wether or not these elements are non-zero). Therefore, our method abolishes the steps where pivot elements are checked to be non-zero, and even zero elements can be used as pivots.
Sparse multivariate polynomial interpolation via the quotient-difference algorithm
Authors: Cuyt Annie , Lee Wen-shin
Published: February 2009

To reconstruct a black box multivariate sparse polynomial from its floating point evaluations, the existing algorithms need to know upper bounds for both the number of terms in the polynomial and the partial degree in each of the variables [2]. On the other hand, Rutishauser's quotient-difference algorithm [7, 3], or the qd-algorithm, is an iterative method that can be use to determine the poles of a meromorphic function from its Taylor coefficients.

Combining the relation between the qd-algorithm, Prony's method and their connections to the Ben-Or/Tiwari algorithm [6], we present a new algorithm for reconstructing sparse multivariate polynomials in floating point arithmetic, in which neither the number of terms nor any partial degrees are required in the input [1].

For example, consider the bivariate black box polynomial function,
f
(
x
1
,
x
2
) = 1/3
x
6/1+4
x
4/2--2.1
x
4/1--4
x
2/2+
x
1
x
2
+4
x
2/1, termed the six-hump camel back function. Evaluate f (x1 , x2 ) at the non-equidistant s-th powers of (1/3, 1/5), in which 3 and 5 are relatively prime, and proceed with the qd-algorithm on the data
f
(1/3, 1/5),
f
(1/3
2
, 1/5
2
),
f
(1/3
3
, 1/5
3
), ....The magnitude of the values in the first five
e
-columns drops from 10
--2
to machine precision, while all values in the sixth
e
-column are of the order of machine precision. We conclude that the number of terms is 6 and obtain the multi-indices in the support directly from the
q
-values:

1/q
1
(S)
→ 9 = 3
2
.

1/q
2
(S)
→ 25 = 5
2
.

1/q
3
(S)
→ 625 = 5
4
.

1/q
2
(S)
→ 15 = 3
1
5
1
.

1/q
1
(S)
→ 81 = 3
4
.

1/q
1
(S)
→ 729 = 3
6
.

After all six multi-indices in
f
are known, the coefficients in
f
can be recovered by a linear system formed by (at least six) evaluations of
f
.

The convergence to zero of some e-columns in the qd-algorithm can be interpreted in an analogous way as the zero discrepancies in the early termination strategy [5, 4]. This is illustrated in Maple.

Our sparse interpolation can be extended to polynomials represented in certain non-standard bases [4]. We show an extension to sparse interpolation of polynomials in the Pochhammer basis and present our current research on sparse polynomial interpolation in the Chebyshev basis, both in floating point arithmetic.
Unified formulas for arbitrary order symbolic derivatives and anti-derivatives of the power-inverse hyperbolic class 1
Authors: Benghorbal Mhenni M.
Published: February 2009

We continue on tackling and giving a complete solution to the problem of finding the nth derivative and the nth anti-derivative, where n can be an integer, a fraction, a real, or a symbol, of elementary and special classes of functions. In general, the solutions are given through unified formulas in terms of the Fox H-function which in many cases can be simplified to less general functions. In this work, we consider two subclasses of the power-inverse hyperbolic class. Namely, the power-inverse hyperbolic sine class {
f
(
x
) :
f
(
x
) = Σ

l

j
=1

Pj
(
x

α
j

)arcsinh(β

j

x

γ
j

), α

j

∈ C, β

j

∈ C\{0},γ

j

∈ R\{0}, (1) and the power-inverse hyperbolic cosine class {
f
(
x
) :
f
(
x
) = Σ

l

j
=1

Pj
(
x

α
j

)arccosh(β

j

x

γ
j

), α

j

∈ C, β

j

∈ C\{0},γ

j

∈ R\{0}, (2) where pj's are polynomials of certain degrees. One of the key points in this work is that the approach does not depend on integration techniques The arbitrary order of differentiation is found according to the Riemann-Liouville definition, whereas the generalized Cauchy n-fold integral is adopted for arbitrary order of integration.

The motivation of this work comes from the area of symbolic computation. The idea is that: Given a function
f
in a variable
x
, can CAS find a formula for the
n
th derivative, the
n
th anti-derivative, or both of
f
? This enhances the power of integration and differentiation of CAS. In Maple, the formulas correspond to invoking the commands diff(
f
(
x
) for the
n
th derivative and int(
f
(
x
),
x$n
) for the
n
th anti-derivative. A software exhibition will be given using Maple.

Example: A unified formula for arcsinh(√
x
) in terms of the Meijer G-function (arcsinh(√
x
))
(n)
=
x

(1/2--
n

over2√π
G
1,2
over
1,2
(1/2,1/2over0,
n
--1/2│
x
) , │
x
│ < 1. (3).

The above G-function reduces to the original function if
n
= 0. It gives derivatives of any order if
n
> 0 and anti-derivatives of any order if
n
< 0.
High β-cell mass prevents streptozotocin-induced diabetes in thioredoxin-interacting protein-deficient mice
Authors: Masson Elodie , Koren Shlomit , Razik Fathima , Goldberg Howard , Kwan Edwin P. , Sheu Laura , Gaisano Herbert Y. , Fantus I. George
Published: February 2009

Thioredoxin-interacting protein (TxNIP) is an endogenous inhibitor of thioredoxin, a ubiquitous thiol oxidoreductase, that regulates cellular redox status. Diabetic mice exhibit increased expression of TxNIP in pancreatic islets, and recent studies suggest that TxNIP is a proapoptotic factor in β-cells that may contribute to the development of diabetes. Here, we examined the role of TxNIP deficiency in vivo in the development of insulin-deficient diabetes and whether it impacted on pancreatic β-cell mass and/or insulin secretion. TxNIP-deficient (Hcb-19/TxNIP−/−) mice had lower baseline glycemia, higher circulating insulin concentrations, and higher total pancreatic insulin content and β-cell mass than control mice (C3H). Hcb-19/TxNIP−/− did not develop hyperglycemia when injected with standard multiple low doses of streptozotocin (STZ), in contrast to C3H controls. Surprisingly, although β-cell mass remained higher in Hcb-19/TxNIP−/− mice compared with C3H after STZ exposure, the relative decrease induced by STZ was as great or even greater in the TxNIP-deficient animals. Consistently, cultured pancreatic INS-1 cells transfected with small-interfering RNA against TxNIP were more sensitive to cell death induced by direct exposure to STZ or to the combination of inflammatory cytokines interleukin-1β, interferon-γ, and tumor necrosis factor-α. Furthermore, when corrected for insulin content, isolated pancreatic islets from TxNIP−/− mice exhibited reduced glucose-induced insulin secretion. These data indicate that TxNIP functions as a regulator of β-cell mass and influences insulin secretion. In conclusion, the relative resistance of TxNIP-deficient mice to STZ-induced diabetes appears to be because of an increase in β-cell mass. However, TxNIP deficiency is associated with sensitization to STZ- and cytokine-induced β-cell death, indicating complex regulatory roles of TxNIP under different physiological and pathological conditions.
Dietary glycemic index influences lipid oxidation but not muscle or liver glycogen oxidation during exercise
Authors: Stevenson E. J. , Thelwall P. E. , Thomas K. , Smith F. , Brand-Miller J. , Trenell M. I.
Published: February 2009

The glycemic index (GI) of dietary carbohydrates influences glycogen storage in skeletal muscle and circulating nonesterified fatty acid (NEFA) concentrations. We hypothesized that diets differing only in GI would alter intramuscular lipid oxidation and glycogen usage in skeletal muscle and liver during subsequent exercise. Endurance-trained individuals ( n = 9) cycled for 90 min at 70% V̇o2peak and then consumed either high- or low-GI meals over the following 12 h. The following day after an overnight fast, the 90-min cycle was repeated. 1H and 13C magnetic resonance spectroscopy was used before and after exercise to assess intramuscular lipid and glycogen content of the vastus muscle group and liver. Blood and expired air samples were collected at 15-min intervals throughout exercise. NEFA availability was reduced during exercise in the high- compared with the low-GI trial (area under curve 44.5 ± 6.0 vs. 38.4 ± 7.30 mM/h, P < 0.05). Exercise elicited an ∼55% greater reduction in intramyocellular triglyceride (IMCL) in the high- vs. low-GI trial (1.6 ± 0.2 vs. 1.0 ± 0.3 mmol/kg wet wt, P < 0.05). There was no difference in the exercise-induced reduction of the glycogen pool in skeletal muscle (76 ± 8 vs. 68 ± 5 mM) or in liver (65 ± 8 vs. 71 ± 4 mM) between the low- and high-GI trials, respectively. High-GI recovery diets reduce NEFA availability and increase reliance on IMCL during moderate-intensity exercise. Skeletal muscle and liver glycogen storage or usage are not affected by the GI of an acute recovery diet.
Insulin blunts the response of glucose-excited neurons in the ventrolateral-ventromedial hypothalamic nucleus to decreased glucose
Authors: Cotero Victoria E. , Routh Vanessa H.
Published: February 2009

Insulin signaling is dysfunctional in obesity and diabetes. Moreover, central glucose-sensing mechanisms are impaired in these diseases. This is associated with abnormalities in hypothalamic glucose-sensing neurons. Glucose-sensing neurons reside in key areas of the brain involved in glucose and energy homeostasis, such as the ventromedial hypothalamus (VMH). Our results indicate that insulin opens the KATP channel on VMH GE neurons in 5, 2.5, and 0.1 mM glucose. Furthermore, insulin reduced the sensitivity of VMH GE neurons to a decrease in extracellular glucose level from 2.5 to 0.1 mM. This change in the glucose sensitivity in the presence of insulin was reversed by the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin (10 nM) but not by the mitogen-activated kinase (MAPK) inhibitor PD-98059 (PD; 50 μM). Finally, neither the AMPK inhibitor compound C nor the AMPK activator AICAR altered the activity of VMH GE neurons. These data suggest that insulin attenuates the ability of VMH GE neurons to sense decreased glucose via the PI3K signaling pathway. Furthermore, these data are consistent with the role of insulin as a satiety factor. That is, in the presence of insulin, glucose levels must decline further before GE neurons respond. Thus, the set point for detection of glucose deficit and initiation of compensatory mechanisms would be lowered.
Thrombosis and Antithrombotic Therapy in Women
Authors: Bailey Alison L. , Scantlebury Dawn C. , Smyth Susan S.
Published: February 2009

Sex-based differences in the prevalence and presentation of arterial and venous thrombosis exist, and emerging data indicate that men and women do not accrue equal benefit from antithrombotic therapy. Sex hormones alter procoagulant protein expression and the function of blood and vascular cells. Sex-based differences in platelet function have been reported, and in animal models, sex-based differences in thrombosis have been noted. Here we review plausible mechanisms that may explain how sex functions as a modifier of thrombosis and summarize clinical data on the interaction between sex and response to antithrombotic therapy.
Estrogen and Mechanisms of Vascular Protection
Authors: Xing Dongqi , Nozell Susan , Chen Yiu-Fai , Hage Fadi , Oparil Suzanne
Published: February 2009

Estrogen has antiinflammatory and vasoprotective effects when administered to young women or experimental animals that appear to be converted to proinflammatory and vasotoxic effects in older subjects, particularly those that have been hormone free for long periods. Clinical studies have raised many important questions about the vascular effects of estrogen that cannot easily be answered in human subjects. Here we review cellular/molecular mechanisms by which estrogen modulates injury-induced inflammation, growth factor expression, and oxidative stress in arteries and isolated vascular smooth muscle cells, with emphasis on the role of estrogen receptors and the nuclear factor-κB (NFκB) signaling pathway, as well as evidence that these protective mechanisms are lost in aging subjects.
Percutaneous Coronary Intervention With Stent Implantation Versus Coronary Artery Bypass Surgery for Treatment of Left Main Coronary Artery Disease
Authors: Park Seung-Jung , Park Duk-Woo
Published: February 2009

On the basis of clinical trials comparing coronary-artery bypass grafting (CABG) with medical therapy, current guideline recommend CABG as the treatment of choice for patients with asymptomatic ischemia, stable angina, or unstable angina/non-ST elevation myocardial infarction who have left main coronary artery disease. Percutaneous coronary intervention can be selectively performed in patients who are candidates for revascularization but who are ineligible for CABG. However, because of advances in periprocedural and postprocedural medical care in patients undergoing either CABG or percutaneous coronary intervention with stenting, new evaluation, and a review of current indications, may be required to determine the standard of care for patients with left main coronary artery disease. Current evidences indicate that stenting results in mortality and morbidity rates that compared favorably with those seen after CABG, suggesting that a current guideline (the Class III recommendation of percutaneous coronary intervention for unprotected left main coronary artery disease) may no longer be justified. Data from several extensive registries and a large clinical trial may have prompted many interventional cardiologists to select percutaneous coronary intervention with stenting as an alternative revascularization strategy for such patients. In addition, these data may inform future guidelines and support the need for well-designed, adequately powered, prospective, randomized trials comparing the 2 revascularization strategies. The cumulative evidence from ongoing and future clinical trials will change the current clinical practice of revascularization for unprotected left main coronary artery disease, which was introduced several decades ago and which has continued to date without major revision.
Inflammation Impairs Reverse Cholesterol Transport In Vivo
Authors: McGillicuddy Fiona C. , de la Llera Moya Margarita , Hinkle Christine C. , Joshi Michelle R. , Chiquoine Elise H. , Billheimer Jeffrey T. , Rothblat George H. , Reilly Muredach P.
Published: February 2009

Background—

Inflammation is proposed to impair reverse cholesterol transport (RCT), a major atheroprotective function of high-density lipoprotein (HDL). The present study presents the first integrated functional evidence that inflammation retards numerous components of RCT.

Methods and Results—

We used subacute endotoxemia in the rodent macrophage-to-feces RCT model to assess the effects of inflammation on RCT in vivo and performed proof of concept experimental endotoxemia studies in humans. Endotoxemia (3 mg/kg SC) reduced
3
H-cholesterol movement from macrophage to plasma and
3
H-cholesterol associated with HDL fractions. At 48 hours, bile and fecal counts were markedly reduced consistent with downregulation of hepatic expression of ABCG5, ABCG8, and ABCB11 biliary transporters. Low-dose lipopolysaccharide (0.3 mg/kg SC) also reduced bile and fecal counts, as well as expression of biliary transporters, but in the absence of effects on plasma or liver counts. In vitro, lipopolysaccharide impaired
3
H-cholesterol efflux from human macrophages to apolipoprotein A-I and serum coincident with reduced expression of the cholesterol transporter ABCA1. During human (3 ng/kg; n=20) and murine endotoxemia (3 mg/kg SC), ex vivo macrophage cholesterol efflux to acute phase HDL was attenuated.

Conclusions—

We provide the first in vivo evidence that inflammation impairs RCT at multiple steps in the RCT pathway, particularly cholesterol flux through liver to bile and feces. Attenuation of RCT and HDL efflux function, independent of HDL cholesterol levels, may contribute to atherosclerosis in chronic inflammatory states including obesity, metabolic syndrome, and type 2 diabetes.
Ligand-Activated Peroxisome Proliferator–Activated Receptor-γ Protects Against Ischemic Cerebral Infarction and Neuronal Apoptosis by 14-3-3ε Upregulation
Authors: Wu Jui-Sheng , Cheung Wai-Mui , Tsai Yau-Sheng , Chen Yi-Tong , Fong Wen-Hsuan , Tsai Hsin-Da , Chen Yu-Chang , Liou Jun-Yang , Shyue Song-Kun , Chen Jin-Jer , Chen Y. Eugene , Maeda Nobuyo , Wu Kenneth K. , Lin Teng-Nan
Published: February 2009

Background—

Thiazolidinediones have been reported to protect against ischemia-reperfusion injury. Their protective actions are considered to be peroxisome proliferator–activated receptor-γ (PPAR-γ)–dependent; however, it is unclear how PPAR-γ activation confers resistance to ischemia-reperfusion injury.

Methods and Results—

We evaluated the effects of rosiglitazone or PPAR-γ overexpression on cerebral infarction in a rat model and investigated the antiapoptotic actions in the N2-A neuroblastoma cell model. Rosiglitazone or PPAR-γ overexpression significantly reduced infarct volume. The protective effect was abrogated by PPAR-γ small interfering RNA. In mice with knock-in of a PPAR-γ dominant-negative mutant, infarct volume was enhanced. Proteomic analysis revealed that brain 14-3-3ε was highly upregulated in rats treated with rosiglitazone. Upregulation of 14-3-3ε was abrogated by PPAR-γ small interfering RNA or antagonist. Promoter analysis and chromatin immunoprecipitation revealed that rosiglitazone induced PPAR-γ binding to specific regulatory elements on the 14-3-3ε promoter and thereby increased 14-3-3ε transcription. 14-3-3ε Small interfering RNA abrogated the antiapoptotic actions of rosiglitazone or PPAR-γ overexpression, whereas 14-3-3ε recombinant proteins rescued brain tissues and N2-A cells from ischemia-induced damage and apoptosis. Elevated 14-3-3ε enhanced binding of phosphorylated Bad and protected mitochondrial membrane potential.

Conclusions—

Ligand-activated PPAR-γ confers resistance to neuronal apoptosis and cerebral infarction by driving 14-3-3ε transcription. 14-3-3ε Upregulation enhances sequestration of phosphorylated Bad and thereby suppresses apoptosis.
Concentrations of Low-Density Lipoprotein Cholesterol and Total Cholesterol Among Children and Adolescents in the United States
Authors: Ford Earl S. , Li Chaoyang , Zhao Guixiang , Mokdad Ali H.
Published: February 2009

Background—

Recently, the American Academy of Pediatrics updated guidance on lipid screening in childhood. Our objective was to examine recent distributions in concentrations of total cholesterol and low-density lipoprotein cholesterol among US children and adolescents and to estimate the prevalence of adolescents who are potentially eligible for pharmacological treatment for elevated concentrations of low-density lipoprotein cholesterol.

Methods and Results—

We used data from the National Health and Nutrition Examination Survey 1999 to 2006 for participants 6 to 17 years of age. The mean concentration for low-density lipoprotein cholesterol for participants 12 to 17 years of age was 90.2 mg/dL (n=2724), and the mean concentration of total cholesterol among participants 6 to 17 years of age was 163.0 mg/dL (n=9868). Depending on the cut points used, an elevated concentration of low-density lipoprotein cholesterol was noted for 5.2% to 6.6% of participants and an elevated concentration of total cholesterol for 9.6% to 10.7%. Approximately 0.8% of adolescents 12 to 17 years of age were potentially eligible for pharmacological treatment for elevated concentrations of low-density lipoprotein cholesterol.

Conclusion—

Given current guidelines, only a small percentage of US adolescents may need pharmacological treatment for elevated concentrations of low-density lipoprotein cholesterol.
Relations of Matrix Remodeling Biomarkers to Blood Pressure Progression and Incidence of Hypertension in the Community
Authors: Dhingra Ravi , Pencina Michael J. , Schrader Peter , Wang Thomas J. , Levy Daniel , Pencina Karol , Siwik Deborah A. , Colucci Wilson S. , Benjamin Emelia J. , Vasan Ramachandran S.
Published: February 2009

Background—

Biomarkers of extracellular matrix remodeling are associated with prevalent hypertension in cross-sectional studies, but their relations to longitudinal changes in blood pressure (BP) and hypertension incidence are unknown.

Methods and Results—

We evaluated 595 nonhypertensive Framingham Offspring Study participants (mean age 55 years; 360 women) without prior heart failure or myocardial infarction who underwent routine measurements of plasma tissue inhibitor of metalloproteinase-1 (TIMP-1), metalloproteinase-9 (MMP-9), and procollagen III N-terminal peptide. We related plasma TIMP-1, procollagen III N-terminal peptide, and MMP-9 to the incidence of hypertension and progression of BP by ≥1 category (defined on the basis of the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure). On follow-up (4 years), 81 participants (51 women) developed hypertension, and 198 (114 women) progressed to a higher BP category. In multivariable models, a 1-SD increment of log-TIMP-1 was associated with a 50% higher incidence of hypertension (95% CI 1.08 to 2.08) and a 21% (95% CI 1.00 to 1.47) higher risk of BP progression. Individuals in the top TIMP-1 tertile had a 2.15-fold increased risk of hypertension (95% CI 0.99 to 4.68) and 1.68-fold (95% CI 1.05 to 2.70) increased risk of BP progression relative to the lowest tertile. Individuals with detectable MMP-9 had a 1.97-fold higher risk of BP progression (95% CI 1.06 to 3.64) than those with undetectable levels. Plasma procollagen III N-terminal peptide was not associated with hypertension incidence or BP progression.

Conclusions—

In the present community-based sample, higher TIMP-1 and MMP-9 concentrations were associated with BP progression on follow-up. Additional studies are warranted to confirm our findings.
Endurance Training in the Spontaneously Hypertensive Rat
Authors: Garciarena Carolina D. , Pinilla Oscar A. , Nolly Mariela B. , Laguens Ruben P. , Escudero Eduardo M. , Cingolani Horacio E. , Ennis Irene L.
Published: February 2009

The effect of endurance training (swimming 90 min/d for 5 days a week for 60 days) on cardiac hypertrophy was investigated in the spontaneously hypertensive rat (SHR). Sedentary SHRs (SHR-Cs) and normotensive Wistar rats were used as controls. Exercise training enhanced myocardial hypertrophy assessed by left ventricular weight/tibial length (228±7 versus 251±5 mg/cm in SHR-Cs and exercised SHRs [SHR-Es], respectively). Myocyte cross-sectional area increased ≈40%, collagen volume fraction decreased ≈50%, and capillary density increased ≈45% in SHR-Es compared with SHR-Cs. The mRNA abundance of atrial natriuretic factor and myosin light chain 2 was decreased by the swimming routine (100±19% versus 41±10% and 100±8% versus 61±9% for atrial natriuretic factor and myosin light chain 2 in SHR-Cs and SHR-Es, respectively). The expression of sarcoplasmic reticulum Ca
2+
pump was significantly augmented, whereas that of Na
+
/Ca
2+
exchanger was unchanged (93±7% versus 167±8% and 158±13% versus 157±7%, sarcoplasmic reticulum Ca
2+
pump and Na
+
/Ca
2+
exchanger in SHR-Cs and SHR-Es, respectively;
P
<0.05). Endurance training inhibited apoptosis, as reflected by a decrease in caspase 3 activation and poly(ADP-ribose) polymerase-1 cleavage, and normalized calcineurin activity without inducing significant changes in the phosphatidylinositol 3-kinase/Akt pathway. The swimming routine improved midventricular shortening determined by echocardiography (32.4±0.9% versus 36.9±1.1% in SHR-Cs and SHR-Es, respectively;
P
<0.05) and decreased the left ventricular free wall thickness/left ventricular cavity radius toward an eccentric model of cardiac hypertrophy (0.59±0.02 versus 0.53±0.01 in SHR-Cs and SHR-Es, respectively;
P
<0.05). In conclusion, we present data demonstrating the effectiveness of endurance training to convert pathological into physiological hypertrophy improving cardiac performance. The reduction of myocardial fibrosis and calcineurin activity plus the increase in capillary density represent factors to be considered in determining this beneficial effect.
Selection Bias in Web Surveys and the Use of Propensity Scores
Authors: Schonlau Matthias , van Soest Arthur , Kapteyn Arie , Couper Mick
Published: February 2009

Web surveys are a popular survey mode, but the subpopulation with Internet access may not represent the population of interest. The authors investigate whether adjusting using weights or matching on a small set of variables makes the distributions of target variables representative of the population. This application has a rich sampling design; the Internet sample is part of an existing probability sample, the Health and Retirement Study, that is representative of the U.S. population aged 50 and older. For the dichotomous variables investigated, the adjustment helps. On average, the sample means in the Internet access sample differ by 6.5 percent before and 3.7 percent after adjustment. Still, a large number of adjusted estimates remain significantly different from their target estimates based on the complete sample. This casts doubt on the common procedure to use only a few variables to correct for the selectivity of convenience samples.
Smartphones
Authors: Raento Mika , Oulasvirta Antti , Eagle Nathan
Published: February 2009

Recent developments in mobile technologies have produced a new kind of device: a programmable mobile phone, the smartphone. In this article, the authors argue that the technological and social characteristics of this device make it a useful tool in social sciences, particularly sociology, social psychology, urban studies, technology assessment, and media studies. The device is willingly carried by a large fraction of people in developed countries, integrates a number of technologies for automatic observation, can be programmed to interact with the user, and can communicate with remote researchers. This allows unobtrusive and cost-effective access to previously inaccessible sources of data on everyday social behavior, such as physical proximity of people, phone calls, and patterns of movement. The authors describe three studies in human behavior that have augmented existing methods with the smartphone, two of which the authors conducted themselves. Based on their experience, the authors critically evaluate the improvements and threats to validity and reliability of smartphone-augmented methods. These approaches are rapidly becoming feasible for the social scientist, since research software for smartphones have been published in open source, which lowers the technical and economic investment needed for their utilization in research.
“I've Never Dealt with a Government Agency Before”
Authors: McKee Guian A.
Published: February 2009

In January 1974, Philadelphia's Somerset Knitting Mills Company announced plans for a new factory in the Franklin-Callowhill East Urban Renewal Area. The project received assistance from the Philadelphia Model Cities Administration and the Philadelphia Industrial Development Corporation—on the condition that Somerset employ neighborhood residents, mostly African Americans and Puerto Ricans, in its new plant. Confounding processes of deindustrialization and urban disinvestment, Somerset remained in its new building until 1992. This article contextualizes the project (and a related “Garment Center” for the local apparel industry) within the ideological and policy history of urban renewal. It argues that with their focus on countering deindustrialization and establishing community partnerships, the Somerset and Garment Center projects offered models of how urban renewal should have proceeded from its inception. The two projects also demonstrated that the local state can reconfigure supposedly “natural” market forces and counter the purportedly inevitable process of urban economic decline.
Demolition Means Progress
Authors: Highsmith Andrew R.
Published: February 2009

In 1960, city officials in Flint, Michigan, announced plans to demolish the St. John Street neighborhood. In support of the clearance project—which promised to replace a segregated black neighborhood with an industrial park and a freeway—executives from General Motors, municipal officials, and downtown boosters argued that redevelopment would provide more jobs and a growth-oriented future. Yet urban renewal in Flint was much more than a top-down campaign for growth. Many civil rights and neighborhood activists also supported St. John redevelopment, viewing urban renewal as an opportunity to secure new housing, desegregation, and clean air. Nevertheless, by the mid-1970s, corporate and city officials had triumphed over local civil rights activists, ultimately presiding over a renewal program that valued short-term industrial growth and ghetto containment over housing equity. Emphasizing state-sanctioned segregation, this article challenges the usefulness of de facto segregation as a descriptor of the North's color lines.