bluuebunny/crossref_metadata_2025 huggingface dataset:
Fixed point theorems in generating spaces of quasi-norm family and applications
Authors: Xiao Jian-Zhong , Zhu Xing-Hua
Published: April 2006

Some new concepts of generating spaces of quasi-norm family are introduced and their linear topological structures are studied. These spaces are not necessarily locally convex. By virtue of some properties in these spaces, several Schauder-type fixed point theorems are proved, which include the corresponding theorems in locally convex spaces as their special cases. As applications, some new fixed point theorems in Menger probabilistic normed spaces and fuzzy normed spaces are obtained.
Coincidence classes in nonorientable manifolds
Authors: Vendrúscolo Daniel
Published: April 2006

We study Nielsen coincidence theory for maps between manifolds of same dimension regardless of orientation. We use the definition of semi-index of a class, review the definition of defective classes, and study the occurrence of defective root classes. We prove a semi-index product formula for lifting maps and give conditions for the defective coincidence classes to be the only essential classes.
Coincidence and fixed point theorems for functions in "Equation missing" -KKM class on generalized convex spaces
Authors: Kuo Tian-Yuan , Huang Young-Ye , Jeng Jyh-Chung , Shih Chen-Yuh
Published: April 2006

We establish a coincidence theorem in "Equation missing"-KKM class by means of the basic defining property for multifunctions in "Equation missing"-KKM. Based on this coincidence theorem, we deduce some useful corollaries and investigate the fixed point problem on uniform spaces.
Wecken type problems for self-maps of the Klein bottle
Authors: Gonçalves DL , Kelly MR
Published: April 2006

We consider various problems regarding roots and coincidence points for maps into the Klein bottle "Equation missing". The root problem where the target is "Equation missing" and the domain is a compact surface with non-positive Euler characteristic is studied. Results similar to those when the target is the torus are obtained. The Wecken property for coincidences from "Equation missing" to "Equation missing" is established, and we also obtain the following 1-parameter result. Families "Equation missing" which are coincidence free but any homotopy between "Equation missing" and "Equation missing", "Equation missing", creates a coincidence with "Equation missing". This is done for any pair of maps such that the Nielsen coincidence number is zero. Finally, we exhibit one such family where "Equation missing" is the constant map and if we allow for homotopies of "Equation missing", then we can find a coincidence free pair of homotopies.
Geometric and homotopy theoretic methods in Nielsen coincidence theory
Authors: Koschorke Ulrich
Published: April 2006

In classical fixed point and coincidence theory, the notion of Nielsen numbers has proved to be extremely fruitful. Here we extend it to pairs "Equation missing" of maps between manifolds of arbitrary dimensions. This leads to estimates of the minimum numbers MCC "Equation missing" (and MC "Equation missing", resp.) of path components (and of points, resp.) in the coincidence sets of those pairs of maps which are "Equation missing". Furthermore we deduce finiteness conditions for MC "Equation missing". As an application, we compute both minimum numbers explicitly in four concrete geometric sample situations. The Nielsen decomposition of a coincidence set is induced by the decomposition of a certain path space "Equation missing" into path components. Its higher-dimensional topology captures further crucial geometric coincidence data. An analoguous approach can be used to define also Nielsen numbers of certain link maps.
Increased Depth of Cellular Imaging in the Intact Lung Using Far‐Red and Near‐Infrared Fluorescent Probes
Authors: Al-Mehdi Abu-Bakr , Patel Mita , Haroon Abu , Reed Darla , Ohlsson-Wilhelm B. , Muirhead K. , Gray Brian D.
Published: April 2006

Scattering of shorter‐wavelength visible light limits the
fluorescence imaging depth of thick specimens such as whole
organs. In this study, we report the use of four newly synthesized
near‐infrared and far‐red fluorescence probes
(excitation/emission, in nm: 644/670; 683/707; 786/814; 824/834)
to image tumor cells in the subpleural vasculature of the intact
rat lungs. Transpelural imaging of tumor cells labeled with
long‐wavelength probes and expressing green fluorescent protein
(GFP; excitation/emission 488/507 nm) was done in the intact rat
lung after perfusate administration or intravenous injection. Our
results show that the average optimum imaging depth for the
long‐wavelength probes is higher (27.8 ± 0.7 μm) than for GFP (20 ± 0.5 μm; p = 0.008; n = 50), corresponding to a
40% increase in the volume of tissue accessible for
high‐resolution imaging. The maximum depth of cell visualization
was significantly improved with the novel dyes (36.4 ± 1 μm from the pleural surface) compared with GFP (30.1 ± 0.5 μm; p = 0.01; n = 50). Stable binding of the long‐wavelength
vital dyes to the plasma membrane also permitted in vivo tracking
of injected tumor cells in the pulmonary vasculature. These probes
offer a significant improvement in the imaging quality of in situ
biological processes in the deeper regions of intact lungs.
A Decision Support Framework for Automated Screening of Diabetic Retinopathy
Authors: Kahai P. , Namuduri K. R. , Thompson H.
Published: April 2006

The early signs of diabetic retinopathy (DR) are depicted by microaneurysms among other signs. A prompt diagnosis when the disease is at the early stage can help prevent irreversible damages to the diabetic eye. In this paper, we propose a decision support system (DSS) for automated screening of early signs of diabetic retinopathy. Classification schemes for deducing the presence or absence of DR are developed and tested. The detection rule is based on binary‐hypothesis testing problem which simplifies the problem to yes/no decisions. An analysis of the performance of the Bayes optimality criteria applied to DR is also presented. The proposed DSS is evaluated on the real‐world data. The results suggest that by biasing the classifier towards DR detection, it is possible to make the classifier achieve good sensitivity.
Elasto‐mammography: Theory, Algorithm, and Phantom Study
Authors: Wang Z. G. , Liu Y. , Sun L. Z. , Wang G. , Fajardo L. L.
Published: April 2006

A new imaging modality framework, called
elasto‐mammography, is proposed to generate the elastograms of
breast tissues based on conventional X‐ray mammography. The
displacement information is extracted from mammography projections
before and after breast compression. Incorporating the
displacement measurement, an elastography reconstruction algorithm
is specifically developed to estimate the elastic moduli of
heterogeneous breast tissues. Case studies with numerical breast
phantoms are conducted to demonstrate the capability of the
proposed elasto‐mammography. Effects of noise with measurement,
geometric mismatch, and elastic contrast ratio are evaluated in
the numerical simulations. It is shown that the proposed
methodology is stable and robust for characterization of the
elastic moduli of breast tissues from the projective displacement
measurement.
Evolution‐Operator‐Based Single‐Step Method for Image Processing
Authors: Sun Yuhui , Wu Peiru , Wei G. W. , Wang Ge
Published: April 2006

This work proposes an evolution‐operator‐based single‐time‐step method for image and signal processing. The key component of the proposed method is a local spectral evolution kernel (LSEK) that analytically integrates a class of evolution partial differential equations (PDEs). From the point of view PDEs, the LSEK provides the analytical solution in a single time step, and is of spectral accuracy, free of instability constraint. From the point of image/signal processing, the LSEK gives rise to a family of lowpass filters. These filters contain controllable time delay and amplitude scaling. The new evolution operator‐based method is constructed by pointwise adaptation of anisotropy to the coefficients of the LSEK. The Perona‐Malik‐type of anisotropic diffusion schemes is incorporated in the LSEK for image denoising. A forward‐backward diffusion process is adopted to the LSEK for image deblurring or sharpening. A coupled PDE system is modified for image edge detection. The resulting image edge is utilized for image enhancement. Extensive computer experiments are carried out to demonstrate the performance of the proposed method. The major advantages of the proposed method are its single‐step solution and readiness for multidimensional data analysis.
Partial Volume Reduction by Interpolation with Reverse Diffusion
Authors: Salvado Olivier , Hillenbrand Claudia M. , Wilson David L.
Published: April 2006

Many medical images suffer from the partial volume effect where a
boundary between two structures of interest falls in the midst of
a voxel giving a signal value that is a mixture of the two. We
propose a method to restore the ideal boundary by splitting a
voxel into subvoxels and reapportioning the signal into the
subvoxels. Each voxel is divided by nearest neighbor interpolation. The gray level of each
subvoxel is considered as “material” able to move between
subvoxels but not between voxels. A partial differential equation
is written to allow the material to flow towards the highest
gradient direction, creating a “reverse” diffusion process. Flow
is subject to constraints that tend to create step edges. Material
is conserved in the process thereby conserving signal. The method
proceeds until the flow decreases to a low value. To test the
method, synthetic images were downsampled to simulate the partial
volume artifact and restored. Corrected images were remarkably
closer both visually and quantitatively to the original images
than those obtained from common interpolation methods: on
simulated data standard deviation of the errors were 3.8%, 6.6%, and 7.1% of the dynamic range for the proposed
method, bicubic, and bilinear interpolation, respectively. The
method was relatively insensitive to noise. On gray level, scanned
text, MRI physical phantom, and brain images, restored images
processed with the new method were visually much closer to
high‐resolution counterparts than those obtained with common
interpolation methods.
High‐Speed Fluorescence Imaging and Intensity Profiling of Femtosecond‐Induced Calcium Transients
Authors: Day Daniel , Cranfield Charles G. , Gu Min
Published: April 2006

We have demonstrated a combined imaging system, where the
physiology of biological specimens can be imaged and profiled at 10–20 frames per second whilst undergoing femtosecond
laser irradiation. Individual GH3 cells labeled with the calcium
fluorophore Fluo‐3 were stimulated using a counter‐propagating
focused femtosecond beam with respect to the imaging system. As a
result of the stimulation, calcium waves can be generated in COS
cells, and laser‐induced calcium oscillations are initiated in the
GH3 cells. Single‐photon fluorescence images and intensity
profiles of the targeted specimens are sampled in real‐time using
a modified PerkinElmer UltraView LCI microscope.
Impacts of Filtration on Contrast‐Detail Detectability of an X‐ray Imaging System
Authors: Zhang Qirong , Rong John , Wu Xizeng , Li Yuhua , Chen Wei R. , Liu Hong
Published: April 2006

The purpose of this study is to investigate the impacts of added filtration on the contrast‐detail detectability of a digital X‐ray imaging system for small animal studies. A digital X‐ray imaging system specifically designed for small animal studies was used. This system is equipped with a micro X‐ray source with a tungsten target and a beryllium window filtration and a CCD‐based digital detector. Molybdenum filters of 0 mm, 0.02 mm, and 0.05 mm in thickness were added. The corresponding X‐ray spectra and contrast‐detail detectabilities were measured using two phantoms of different thicknesses simulating breast tissue under different exposures. The added Mo filters reduced the low‐energy as well as the high‐energy photons, hence providing a narrowband for imaging quality improvement. In the experiments with a 1.15 cm phantom, the optimal image detectability was observed using 22 kVp and the 0.05 mm Mo filter. With the 2.15 cm phantom, the best detectability was obtained with 22 kVp and the 0.02 mm Mo filter. Our experiments showed that appropriate filtrations could reduce certain low‐ and high‐energy components of X‐ray spectra which have limited contributions to image contrast. At the same time, such filtration could improve the contrast‐detail detectability, particularly at relatively low kVp and high filtration. Therefore, optimal image quality can be obtained with the same absorbed radiation dose by the subjects when appropriate filtration is used.
Load matching in a direct‐coupled photovoltaic system‐application to Thevenin′s equivalent loads
Authors: Balouktsis A. , Karapantsios T. D. , Anastasiou K. , Antoniadis A. , Balouktsis I.
Published: April 2006

A methodology is developed for the assessment of load matching and
further estimation of the optimum photovoltaic (PV) arrays
arrangement over a prolonged period of time. The method calls for
the calculation of the appropriate effectiveness factor defined as
the ratio of the load energy over the maximum energy that can be
produced by the PV array for a specific time period. The
effectiveness factor depends on the PV array characteristics, the
load characteristics, and the solar irradiance conditions. To
produce realistic predictions for the effectiveness factor and the
PV arrays arrangement with validity over long periods of time, the
present statistical model describing irradiance employs a
stochastic variation of solar radiation over a long period of time
and not just a fixed diurnal variation as traditionally done in
the past. Simulations are performed for the case of Thevenin′s
equivalent loads. In order to generalize the analysis, the
simulation results are presented in a reduced form based on the
values of the voltage and current corresponding to the maximum
power of the PV array. The results are presented in multiple‐curve
comprehensive plots, which allow to determine the optimum
photovoltaic array panel′s arrangement without engaging
sophisticated mathematical calculations.
Free‐standing microcrystals of a fluorescent organic dye: Preparation and spectroscopic study
Authors: Abyan Mouhammad , Bîrlă Liliana , Bertorelle Franck , Rodrigues Fernanda , Fery-Forgues Suzanne
Published: April 2006

Suspensions of microcrystals were obtained from an organic
fluorescent dye, 4‐n‐octylamino‐7‐nitrobenz‐2‐oxa‐1,3‐diazole,
by reprecipitation in water in the presence of various
macromolecules: anionic or cationic PAMAM dendrimer, poly(acrylic
acid, sodium salt), poly(acrylamide), and calf thymus DNA. The use
of these additives allowed the size and shape of the microcrystals
to be controlled. A study by UV/vis absorption and fluorescence
spectroscopy revealed some common points, but also some
interesting differences, in the optical behaviour of the five
samples.
The dynamics of excited state structural relaxation of 4‐dimethylaminobenzonitrile (DMABN) and related compounds
Authors: Volchkov Valery , Uzhinova Lyubov′ , Uzhinov Boris
Published: April 2006

The excited state structural relaxation of 4‐dimethylaminobenzenes with various para‐acceptor
substituents having double‐band emission, local excited (LE) and
charge transfer (CT), has been investigated. Fluorescence
measurements at different temperatures and in different solvents
have confirmed the existence of viscosity‐dependent, temperature,
and polarity‐activated relaxation. The kinetics analysis has shown
that the radiative deactivation rate constants of the individual
LE and CT states differ by 7–112‐fold. The dipole moment
changes at the excitation for CT states are significantly larger
than those for LE states. The spectral‐kinetics behavior of
compounds studied agrees with the models A → A∗ → B∗ or A → A∗↔B∗, where A∗ is the local excited planar and B∗ is the relaxed twisted state of the molecule.
The rate constants of the twisted state formation have been
calculated in the temperature range 293–77 K. The activation energies of forward process for compounds studied have
been estimated.
Model and Stability Analysis of a Flexible Bladed Rotor
Authors: Lesaffre N. , Sinou J.-J. , Thouverez F.
Published: April 2006

This paper presents a fully bladed flexible rotor and outlines the
associated stability analysis. From an energetic approach based on
the complete energies and potentials for Euler‐Bernoulli beams, a
system of equations is derived, in the rotational frame, for the
rotor. This later one is made of a hollow shaft modelled by an
Euler‐Bernoulli beam supported by a set of bearings. It is
connected to a rigid disk having a rotational inertia. A full set
of flexible blades is also modelled by Euler‐Bernoulli beams
clamped in the disk. The flexural vibrations of the blades as well
as those of the shaft are considered. The evolution of the
eigenvalues of this rotor, in the corotational frame,
is studied. A stability detection method, bringing coalescence and
loci separation phenomena to the fore, in case of an asymmetric
rotor, is undertaken in order to determine a parametric domain
where turbomachinery cannot encounter damage. Finally, extensive
parametric studies including the length and the stagger angle of
the blades as well as their flexibility are presented in order to
obtain robust criteria for stable and unstable areas prediction.
Rotordynamics of Turbine Labyrinth Seals with Rotor Axial Shifting
Authors: Xi Jinxiang , Rhode David L.
Published: April 2006

Rotors in high‐performance steam turbines experience a significant
axial shifting during starting and stopping processes due to
thermal expansion, for example. This axial shifting could
significantly alter the flow pattern and the flow‐induced
rotordynamic forces in labyrinth seals, which in turn, can
considerably affect the rotor‐seal system performance. This paper
investigates the influence of the rotor axial shifting on leakage
rate as well as rotordynamic forces in high‐low labyrinth seals
over a range of seal clearances and inlet swirl velocities. A
well‐established CFD‐perturbation model was employed to predict
the rotordynamic coefficients. A surprisingly large effect was
detected for rotordynamic characteristics due to rotor shifting.
It was also found that a less destabilizing effect arose from
rotor axial shifting in the leakage flow direction, whereas a more
destabilizing effect arose from shifting against the leakage flow
direction. Further, a tentative explanation was proposed for the
large sensitivities of dynamic forces to rotor axial shifting.
Estimating from cross-sectional categorical data subject to misclassification and double sampling: Moment-based, maximum likelihood and quasi-likelihood approaches
Authors: Tzavidis Nikos , Lin Yan-Xia
Published: April 2006

We discuss alternative approaches for estimating from cross-sectional categorical data in the presence of
misclassification. Two parameterisations of the misclassification model are reviewed. The first employs misclassification
probabilities and leads to moment-based inference. The second employs calibration probabilities and leads to maximum likelihood inference. We show that maximum likelihood estimation can be alternatively performed by employing misclassification probabilities and a missing data specification. As an alternative to maximum likelihood estimation we propose a quasi-likelihood parameterisation of the misclassification model. In this context an explicit definition of the likelihood function is avoided and a different way of resolving a missing data problem is provided.
Variance estimation for the alternative point estimators is considered. The different approaches are illustrated using real data from the UK Labour Force Survey and simulated data.
Upper and lower solutions method for differential inclusions with integral boundary conditions
Authors: Benchohra Mouffak , Ouahab Abdelghani
Published: April 2006

A nonlinear alternative of the Leray‐Schauder type for multivalued maps combined with upper and lower solutions is used to investigate the existence of solutions for second‐order differential inclusions with integral boundary conditions.
Equivalence and stability of random fixed point iterativeprocedures
Authors: Beg Ismat , Abbas Mujahid
Published: April 2006

We generate a sequence of measurable mappings iteratively and
study necessary conditions for its strong convergence to a random
fixed point of strongly pseudocontractive random operator. We
establish the weak convergence of an implicit random iterative
procedure to common random fixed point of a finite family of
nonexpansive random operators in Hilbert spaces. We prove the
equivalence between the convergence of random Ishikawa and random
Mann iterative schemes for contraction random operator and
strongly pseudocontractive random operator. We also examine the
stability of random fixed point iterative procedures for the
random operators satisfying certain contractive
conditions in the context of metric spaces.
Linear filtering of systems with memory and application to finance
Authors: Inoue A. , Nakano Y. , Anh V.
Published: April 2006

We study the linear filtering problem for systems driven by
continuous Gaussian processes V(1) and V(2) with memory
described by two parameters. The processes V(j) have the virtue that they possess stationary increments and simple
semimartingale representations simultaneously. They allow for
straightforward parameter estimations. After giving the
semimartingale representations of V(j) by innovation theory,
we derive Kalman‐Bucy‐type filtering equations for the systems. We
apply the result to the optimal portfolio problem for an investor
with partial observations. We illustrate the tractability of the
filtering algorithm by numerical implementations.
A remark on recent results for finding zeroes ofaccretive operators
Authors: Moudafi Abdellatif
Published: April 2006

By means of the Yosida approximate of an accretive operator, we
extended two recent results by Chidume and Chidume and
Zegeye (2003) to set‐valued operators, and we made the
connection with two recent convergence results obtained by
Benavides etal for a relaxed version of the so‐called
proximal point algorithm.
Orbital stability of standing waves for a class of Schrödinger equations with unbounded potential
Authors: Chen Guanggan , Zhang Jian , Wei Yunyun
Published: April 2006

This paper is concerned with the nonlinear Schrödinger
equation with an unbounded potential iϕt = −Δϕ + V(x)ϕ − μ|ϕ|p−1ϕ − λ|ϕ|q−1ϕ, x ∈ ℝN, t ≥ 0, where μ > 0, λ > 0, and 1 < p < q < 1 + 4/N. The potential V(x) is bounded
from below and satisfies V(x) → ∞ as |x| → ∞. From variational calculus and a
compactness lemma, the existence of standing waves and their
orbital stability are obtained.
Characterization of the marginal distributions of Markovprocesses used in dynamic reliability
Authors: Cocozza-Thivent Christiane , Eymard Robert , Mercier Sophie , Roussignol Michel
Published: April 2006

In dynamic reliability, the evolution of a system is described by
a piecewise deterministic Markov process

with state‐space E × ℝd, where E is finite. The
main result of the present paper is the characterization of the
marginal distribution of the Markov process

at time t, as the unique solution of a
set of explicit integro‐differential equations, which can be seen
as a weak form of the Chapman‐Kolmogorov equation. Uniqueness is
the difficult part of the result.
Exact transient solution of a state‐dependent birth‐death process
Authors: Parthasarathy P. R. , Sudhesh R.
Published: April 2006

A power series expression in closed form for the transient
probabilities of a state‐dependent birth‐death
process is presented with suitable illustrations.
The TGF‐β1/Upstream Stimulatory Factor‐Regulated PAI‐1 Gene:Potential Involvement and a Therapeutic Target in Alzheimer′sDisease
Authors: Higgins Paul J.
Published: April 2006

Amyloid peptide (Aβ) aggregates, derived from initial
β‐site proteolytic processing of the amyloid precursor
protein (APP), accumulate in the brains of Alzheimer′s disease
patients. The plasmin‐generating cascade appears to serve a
protective role in the central nervous system since
plasmin‐mediated proteolysis of APP utilizes the α
site,
eventually generating nontoxic peptides, and plasmin also degrades
Aβ. The conversion of plasminogen to plasmin by tissue‐type
plasminogen activator in the brain is negatively regulated by
plasminogen activator inhibitor type‐1 (PAI‐1) resulting in
attenuation of plasmin‐dependent substrate degradation with
resultant accumulation of Aβ. PAI‐1 and its major
physiological inducer TGF‐β1, moreover, are increased in
models of Alzheimer′s disease and have been implicated in the
etiology and progression of human neurodegenerative disorders.
This review highlights the potential role of PAI‐1 and TGF‐β1 in this process. Current molecular events associated with
TGF‐β1‐induced PAI‐1 transcription are presented with
particular relevance to potential targeting of PAI‐1 gene
expression as a molecular approach to the therapy of
neurodegenerative diseases associated with increased PAI‐1
expression such as Alzheimer′s disease.
LINE‐1 Hypomethylation in a Choline‐Deficiency‐Induced Liver Cancer in Rats: Dependence on Feeding Period
Authors: Asada Kiyoshi , Kotake Yashige , Asada Rumiko , Saunders Deborah , Broyles Robert H. , Towner Rheal A. , Fukui Hiroshi , Floyd Robert A.
Published: April 2006

Chronic feeding of methyl‐donor (methionine, choline, folic acid,
and vitamin B12) deficient diet induces hepatocellular carcinoma
formation in rats. Previous studies have shown that promoter CpG
islands in various cancer‐related genes are aberrantly methylated
in this model. Moreover, the global genome in
methyl‐donor‐deficient diet fed rats contains a lesser amount of
5‐methylcytosine than control livers. It is speculated that more
than 90% of all 5‐methylcytosines lie within the CpG islands of
the transposons, including the long/short interspersed nucleotide
elements (LINE and SINE). It is considered that the
5‐methylcytosines in LINE‐1 limit the ability of retrotransposons
to be activated and transcribed; therefore, the extent of
hypomethylation of LINE‐1 could be a surrogate marker for aberrant
methylation in other tumor‐related genes as well as genome
instability. Additionally, LINE‐1 methylation status has been
shown to be a good indicator of genome‐wide methylation. In this
study, we determined cytosine methylation status in the LINE‐1
repetitive sequences of rats fed a choline‐deficient (CD) diet for
various durations and compared these with rats fed a
choline‐sufficient (CS) diet. The methylation status of LINE‐1 was
assessed by the combined bisulfite restriction analysis (COBRA)
method, where the amount of bisulfite‐modified and RsaI‐cleaved
DNA was quantified using gel electrophoresis. Progressive
hypomethylation was observed in LINE‐1 of CD livers as a function
of feeding time; that is, the amount of cytosine in total cytosine
(methylated and unmethylated) increased from 11.1% (1 week) to
19.3% (56 weeks), whereas in the control CS livers, it increased
from 9.2% to 12.9%. Hypomethylation in tumor tissues was
slightly higher (6%) than the nontumorous surrounding tissue. The
present result also indicates that age is a factor influencing the
extent of cytosine methylation.
Do Small RNAs Interfere With LINE‐1?
Authors: Soifer Harris S.
Published: April 2006

Long interspersed elements (LINE‐1 or L1) are the most active
transposable elements in the human genome. Due to their high copy
number and ability to sponsor retrotransposition of nonautonomous
RNA sequences, unchecked L1 activity can negatively impact the
genome by a number of means. Substantial evidence in lower
eukaryotes demonstrates that the RNA interference (RNAi) machinery
plays a major role in containing transposon activity. Despite
extensive analysis in other eukaryotes, no experimental evidence
has been presented that L1‐derived siRNAs exist, or that the RNAi
plays a significant role in restricting L1 activity in the human
genome. This review will present evidence showing a direct role
for RNAi in suppressing the movement of transposable elements in
other eukaryotes, as well as speculate on the role RNAi might play
in protecting the human genome from LINE‐1 activity.
Dysregulation of Protein Phosphorylation/Dephosphorylation in Alzheimer′s Disease: A Therapeutic Target
Authors: Gong Cheng-Xin , Liu Fei , Grundke-Iqbal Inge , Iqbal Khalid
Published: April 2006

Studies during the last two decades have provided new insights
into the molecular mechanism of Alzheimer′s disease (AD). One of
the milestone findings in AD research was the demonstration that
neurofibrillary degeneration characterized by tau pathology is
central to the pathogenesis of AD and other tauopathies and that
abnormal hyperphosphorylation of tau is pivotal to neurofibrillary
degeneration. This article reviews the recent research advances in
tau pathology and the underlying dysregulation of the protein
phosphorylation/dephosphorylation system. An updated model of the
mechanism of neurofibrillary degeneration is also presented, and a
promising therapeutic target to treat AD by correcting
dysregulation of protein phosphorylation/dephosphorylation is
discussed.
The Potential Regulation of L1 Mobility by RNA Interference
Authors: Horman Shane R. , Svoboda Petr , Prak Eline T. Luning
Published: April 2006

The hypothesis that RNA interference constrains L1 mobility seems
inherently reasonable: L1 mobility can be dangerous and L1 RNA,
the presumed target of RNAi, serves as a critical
retrotransposition intermediate. Despite its plausibility, proof
for this hypothesis has been difficult to obtain. Studies
attempting to link the L1 retrotransposition frequency to
alterations in RNAi activity have been hampered by the long times
required to measure retrotransposition frequency, the pleiotropic
and toxic effects of altering RNAi over similar time periods, and
the possibility that other cellular machinery may contribute to
the regulation of L1s. Another problem is that the commonly used
L1 reporter cassette may serve as a substrate for RNAi. Here we
review the L1‐RNAi hypothesis and describe a genetic assay with a
modified reporter cassette that detects approximately 4 times more
L1 insertions than the conventional retrotransposition assay.
DNA Damage and L1 Retrotransposition
Authors: Farkash Evan A. , Prak Eline T. Luning
Published: April 2006

Barbara McClintock was the first to suggest that transposons are a
source of genome instability and that genotoxic stress assisted in
their mobilization. The generation of double‐stranded DNA breaks
(DSBs) is a severe form of genotoxic stress that threatens the
integrity of the genome, activates cell cycle checkpoints, and, in
some cases, causes cell death. Applying McClintock′s stress
hypothesis to humans, are L1 retrotransposons, the most active
autonomous mobile elements in the modern day human genome,
mobilized by DSBs? Here, evidence that transposable elements,
particularly retrotransposons, are mobilized by genotoxic stress
is reviewed. In the setting of DSB formation, L1 mobility may be
affected by changes in the substrate for L1 integration, the DNA
repair machinery, or the L1 element itself. The review concludes
with a discussion of the potential consequences of L1 mobilization
in the setting of genotoxic stress.
The ORF1 Protein Encoded by LINE‐1: Structure and Function During L1 Retrotransposition
Authors: Martin Sandra L.
Published: April 2006

LINE‐1 or L1 is an autonomous non‐LTR retrotransposon in mammals.
Retrotransposition requires the function of the two
L1‐encoded polypeptides, ORF1p and ORF2p. Early recognition of
regions of homology between the predicted amino acid sequence of
ORF2 and known endonuclease and reverse transcriptase enzymes led
to testable hypotheses regarding the function of ORF2p in
retrotransposition. As predicted, ORF2p has been demonstrated to
have both endonuclease and reverse transcriptase activities. In
contrast, no homologs of known function have contributed to our
understanding of the function of ORF1p during retrotransposition.
Nevertheless, significant advances have been made such that we now
know that ORF1p is a high‐affinity RNA‐binding protein that forms
a ribonucleoprotein particle together with L1 RNA. Furthermore,
ORF1p is a nucleic acid chaperone and this nucleic acid chaperone
activity is required for L1 retrotransposition.
LINE‐1 Endonuclease‐Dependent Retrotranspositional Events Causing Human Genetic Disease: Mutation Detection Bias and Multiple Mechanisms of Target Gene Disruption
Authors: Chen Jian-Min , Férec Claude , Cooper David N.
Published: April 2006

LINE‐1 (L1) elements are the most abundant autonomous non‐LTR retrotransposons in the human genome. Having recently performed a meta‐analysis of L1 endonuclease‐mediated retrotranspositional
events causing human genetic disease, we have extended this study by focusing on two key issues, namely, mutation detection bias and the multiplicity of mechanisms of target gene disruption. Our analysis
suggests that whereas an ascertainment bias may have generally militated against the detection of autosomal L1‐mediated insertions, autosomal L1 direct insertions could have been disproportionately overlooked owing to their unusually large size. Our analysis has also indicated that the mechanisms underlying the functional disruption of target genes by L1‐mediated retrotranspositional events are likely to be dependent on several different factors such as the type of insertion (L1 direct, L1 trans‐driven Alu, or SVA), the precise locations of the inserted sequences within the target gene regions, the length of the inserted sequences, and possibly also their orientation.
HIV Neurotoxicity: Potential Therapeutic Interventions
Authors: Wallace David R.
Published: April 2006

Individuals suffering from human immunodeficiency virus type 1
(HIV‐1) infection suffer from a wide range of neurological
deficits. The most pronounced are the motor and cognitive deficits
observed in many patients in the latter stages of HIV infection.
Gross postmortem inspection shows cortical atrophy and widespread
neuronal loss. One of the more debilitating of the HIV‐related
syndromes is AIDS‐related dementia, or HAD. Complete understanding
of HIV neurotoxicity has been elusive. Both direct and indirect
toxic mechanisms have been implicated in the neurotoxicity of the
HIV proteins, Tat and gp120. The glutamatergic system, nitric
oxide, calcium, oxidative stress, apoptosis, and microglia have all
been implicated in the pathogenesis of HIV‐related neuronal
degeneration. The aim of this review is to summarize the most
recent work and provide an overview to the current theories of
HIV‐related neurotoxicity and potential avenues of therapeutic
interventions to prevent the neuronal loss and motor/cognitive
deficits previously described.
Site‐Directed Mutagenesis to Assess the Binding Capacityof Class S Protein of Staphylococcus aureus Leucotoxins to the Surface of Polymorphonuclear Cells
Authors: Moussa L. Baba , Werner S. , Coraiola M. , Colin D. A. , Keller D. , Sanni A. , Serra M. Dalla , Monteil H. , Prévost G.
Published: April 2006

Staphylococcal leucotoxins result from the association of class S
components and class F component inducing the activation and the
permeabilization of the target cells. Like α‐toxin, the
leucotoxins are pore‐forming toxins with more than 70%
β‐sheet. This was confirmed by attenuated total reflectance
Fourier transform infrared (ATR‐FTIR) spectroscopy. In addition,
threonine 28 of a predicted and conserved β‐sheet at the
N‐terminal extremity of class S proteins composing leucotoxins
aligns with histidine 35 of α‐toxin, which has a key role
in oligomerization of the final pore. Flow cytometry was used to
study different aminoacid substitutions of the threonine 28 in
order to evaluate its role in the biological activity of these
class S proteins. Finally, results show that threonine 28 of the
leucotoxin probably plays a role similar to that of histidine 35
of α‐toxin. Mutations on this threonin largely influenced
the secondary interaction of the class F component and led to
inactive toxin.
Fuzzy Logic in Medicine and Bioinformatics
Authors: Torres Angela , Nieto Juan J.
Published: April 2006

The purpose of this paper is to present a general view of the current applications of fuzzy logic in medicine and bioinformatics. We particularly review the medical literature using fuzzy logic. We then recall the geometrical interpretation of fuzzy sets as points in a fuzzy hypercube and present two concrete illustrations in medicine (drug addictions) and in bioinformatics (comparison of genomes).
Circulating Total and Active Metalloproteinase‐9 and Tissue Inhibitor of Metalloproteinases‐1 in Patients with Systemic Lupus Erythomatosus
Authors: Robak Ewa , Wierzbowska Agnieszka , Chmiela Magdalena , Kulczycka Liliana , Sysa-Jędrejowska Anna , Robak Tadeusz
Published: April 2006

We investigated the serum concentration of total metalloproteinase‐9 (tMPP‐9), active MMP‐9 (aMMP‐9), and tissue inhibitor of metalloproteinase‐1 (TIMP‐1) in a group of 41 patients with SLE and 20 healthy controls. Serum levels of tMMP‐9 and TIMP‐1 were assessed by an enzyme‐linked immunosorbent assay (ELISA) and aMMP‐9 by fluorometric assay. The tMMP‐9 level was lower in SLE patients (mean 262 ng/mL) than in healthy volunteers (mean 325 ng/mL) (P = .048). Similarly, aMMP‐9 level was lower in SLE patients (mean 121 ng/mL) than in control group (mean 169 ng/mL) (P = .0355) and lower in active SLE (mean 54 ng/mL) than in inactive disease (mean 99 ng/mL) (P = .033). TIMP‐1 level was also lower in SLE patients (mean 181 ng/mL) than in control group (mean 233 ng/mL) (P = .004). In SLE patients, a positive correlation was found between tMMP‐9 and aMMP‐9 (ρ = 0.568; P = .001). We also found a positive correlation of tMMP‐9 and TIMP‐1 with VEGF concentrations (ρ = 0.450, P = .005 and ρ = 0.387; P = .018, resp). tMMP‐9, aMMP‐9, and TIMP‐1 serum levels are lower in SLE patients than in healthy control group.
Unexpected Smoking‐Linked High MMP‐9 in Induced Sputum of Hazardous Dust‐Exposed Workers
Authors: Lerman Yehuda , Moscovich Abraham , Fireman Elizabeth
Published: April 2006

We investigated whether metalloproteinase‐9 (MMP‐9) values in
induced sputum (IS) and pulmonary function tests can serve
as a marker of damage and intensity of exposure to hazardous dust.
Thirty‐nine factory employees (28 workers exposed to metal
particles and 11 supposedly nonexposed office workers) underwent
IS induction. Samples were processed by conventional methods
within 2 hours. The proportion of particles with diameters of
0–2 μ in IS samples was significantly higher in
nonexposed than exposed workers and in smoker compared to nonsmoker workers. MMP‐9 and
TIMP‐1 levels were similar for both groups. A linear regression
model for MMP‐9 based on exposure, smoking habits, and proportion
of particles <5 μ revealed a positive correlation
between each of the explanatory variables and MMP‐9 values. MMP‐9
may serve as a marker for pulmonary injury.
Testicular Nitric Oxide and Thiobarbituric Acid Reactive Substances Levels in Obstructive Azoospermia: A Possible Role in Pathophysiology of Infertility
Authors: Başar M. Murad , Kisa Üçler , Tuğlu Devrim , Yilmaz Erdal , Başar Halil , Çağlayan Osman , Batislam Ertan
Published: April 2006

Objective. The aim of the study is to evaluate the levels of nitrite/nitrate and thiobarbituric acid reactive substances (TBARS) and their relationship with seminal parameters in experimental obstructive azoospermic rats to explain the possible mechanism of impaired sperm quality in obstructive azoospermia. Methods . A total of 10 male Spraque‐Dawley rats underwent bilateral vas resection and ligation (Group‐1 = vasectomy group). The findings were compared with control group (Group‐2 = sham group,n = 10). Animals were sacrificed 8 weeks after surgery. Testes were removed and used for the evaluation of nitrate/nitrite and TBARS levels and for histology. Epididymal‐aspirated seminal plasma was used for semen count and morphological analysis according to the Kruger criteria. Results. Testicular tissue nitrate/nitrite and TBARS levels were 35.7 ± 3.1μmol/g protein and 3.7 ± 0.1 nmol/g protein in Group‐1, and 19.3 ± 0.7μmol/g protein and 3.1 ± 0.1 nmol/g protein in Group‐2, respectively. Both parameters showed statistical differences between the two groups. Testicular tissue nitrate/nitrite and TBARS levels showed negative and statistically significant correlations with sperm motility and morphology. Conclusions. The present study showed that testicular nitrate/nitrite and TBARS levels were increased in obstructive azoospermia. For that reason, we concluded that antioxidant treatment can be recommended to patients before sperm extraction for artificial reproduction due to obstructive infertility after vasectomy reversal.
Multiplex Bead Array Assay for Detection of 25 SolubleCytokines in Blister Fluid of Patients with ComplexRegional Pain Syndrome Type 1
Authors: Heijmans-Antonissen Claudia , Wesseldijk Feikje , Munnikes Renate JM , Huygen Frank JPM , van der Meijden Patrick , Hop Wim C. J. , Hooijkaas Herbert , Zijlstra Freek J.
Published: April 2006

Inflammatory processes are known to be involved at least in the
early phase of complex regional pain syndrome type 1 (CRPS1).
Blister fluid obtained from the involved extremities displayed
increased amounts of proinflammatory cytokines IL‐6 and TNFα
compared with the noninvolved extremities. The aim of this paper
is to investigate the involvement of mediators by measurement of
several other cytokines using new detection techniques that enable
multiple cytokine measurement in small samples. The use of a
multiplex‐25 bead array cytokine assay and Luminex technology
enabled simultaneous measurement of representative (1)
proinflammatory cytokines such as GM‐CSF, IL‐1β, IL‐1RA,
IL‐6, IL‐8, and TNF‐α; (2) Th1/Th2 distinguishing
cytokines IFN‐γ, IL‐2, IL‐2R, IL‐4, IL‐5, and IL‐10; (3)
nonspecific acting cytokines IFN‐α, IL‐7, IL‐12p40/p70,
IL‐13, IL‐15, and IL‐17; and (4) chemokines eotaxin, IP‐10, MCP‐1,
MIP‐1α, MIP‐1β, MIG, and RANTES. Although minimal
detection levels are significantly higher in the bead array system
than those in common ELISA assays, in blister fluid, IL‐1RA, IL‐6,
IL‐8, TNF‐α, IL‐12p40/p70, MCP‐1, and MIP‐1β were
detectable and increased in CRPS1 affected extremities. Levels of
IL‐6 and TNF‐α simultaneously measured by ELISA (Sanquin
Compact kit) and by multiplex‐25 bead array assay (Biosource) were
highly correlated (r = 0.85, P < .001
for IL‐6 and r = 0.88,
P < .001 for TNF‐α). Furthermore, IP‐10 and eotaxin were
detectable but diminished in CRPS1, whereas detectable amounts of
IL‐10 were similar in involved and noninvolved extremities.
Multiplex bead array assays are useful systems to establish the
involvement of cytokines in inflammatory processes by measurements
in blister fluids of CRPS1. Ten representative cytokines were
detectable. However, detection levels and amounts measured are at
least 3 times higher in the multiplex‐25 array assay than in the
ELISA assays used simultaneously for the measurement of cytokines.
Spatiotemporal Pattern of Neuroinflammation After Impact‐Acceleration Closed Head Injury in the Rat
Authors: Rooker Servan , Jander Sebastian , Reempts Jos Van , Stoll Guido , G. Jorens Philippe , Borgers Marcel , Verlooy Jan
Published: April 2006

Inflammatory processes have been implicated in the pathogenesis of
traumatic brain damage. We analyzed the spatiotemporal expression
pattern of the proinflammatory key molecules: interleukin‐1β,
interleukin‐6, tumor necrosis factor‐α, and inducible nitric
oxide synthase in a rat closed head injury (CHI) paradigm. 51 rats
were used for RT‐PCR analysis after CHI, and 18 for
immunocytochemistry. We found an early upregulation of
IL‐1β, IL‐6, and TNF‐α mRNA between 1 h and
7 h after injury; the expression of iNOS mRNA only revealed a
significant increase at 4 h. After 24 h, the expression
decreased towards baseline levels, and remained low until 7 d
after injury. Immunocytochemically, IL‐1β induction was
localized to ramified microglia in areas surrounding the primary
impact place as well as deeper brain structures. Our study shows
rapid induction of inflammatory gene expression that exceeds by
far the primary impact site and might therefore contribute to
tissue damage at remote sites.
Stability of differential inclusions: A computational approach
Authors: Azhmyakov Vadim
Published: April 2006

We present a technique for analysis of asymptotic stability for a
class of differential inclusions. This technique is based on the
Lyapunov‐type theorems. The construction of the Lyapunov functions
for differential inclusions is reduced to an auxiliary problem of mathematical
programming, namely, to the problem of searching saddle points of
a suitable function. The computational approach to the auxiliary
problem contains a gradient‐type algorithm for saddle‐point problems. We also extend our main results to systems
described by difference inclusions. The obtained numerical schemes
are applied to some illustrative examples.
Conservation of filtering in manufacturing systems with unreliable machines and finished goods buffers
Authors: Li Jingshan , Enginarlar E. , Meerkov Semyon M.
Published: April 2006

This paper addresses the issue of reliable satisfaction of customer demand by unreliable production systems. In the framework of a simple production‐storage‐customer model, we show that this can be accomplished by using an appropriate level of filtering of production randomness. The filtering is ensured by finished goods
buffers (filtering in space) and shipping periods (filtering in time). The following question is considered: how are filtering in space and filtering in time interrelated? As an answer, we show that there exists a conservation law: in lean manufacturing systems, the amount of filtering in space multiplied by the amount of filteringin time (both measured in appropriate dimensionless units) ispractically constant. Along with providing an insight into the
nature of manufacturing systems, this law offers a tool for selecting the smallest, that is, lean, finished goods buffering, which is necessary and sufficient to ensure the desired level ofcustomer demand satisfaction.
Analysis of linear and nonlinear stiff problems using the RK‐Butcher algorithm
Authors: Sekar S.
Published: April 2006

I present a numerical solution of linear and nonlinear stiff
problems using the RK‐Butcher algorithm. The obtained discrete
solutions using the RK‐Butcher algorithm are found to be very
accurate and are compared with the exact solutions of the linear
and nonlinear stiff problems and also with the Runge‐Kutta method
based on arithmetic mean (RKAM). A topic of stability for the
RK‐Butcher algorithm is discussed in detail. Error graphs for
discrete and exact solutions are presented in a graphical form to
show the efficiency of the RK‐Butcher algorithm. The results
obtained show that RK‐Butcher algorithm is more useful for solving
linear and nonlinear stiff problems and the solution can be
obtained for any length of time.
Algorithmic analysis of the maximum level length in general‐block two‐dimensional Markov processes
Authors: Artalejo Jesus R. , Chakravarthy Srinivas R.
Published: April 2006

Two‐dimensional continuous‐time Markov chains (CTMCs) are useful
tools for studying stochastic models such as queueing, inventory,
and production systems. Of particular interest in this paper is
the distribution of the maximal level visited in a busy period
because this descriptor provides an excellent measure of the
system congestion. We present an algorithmic analysis for the
computation of its distribution which is valid for Markov chains
with general‐block structure. For a multiserver batch arrival
queue with retrials and negative arrivals, we exploit the
underlying internal block structure and present numerical examples
that reveal some interesting facts of the system.