bluuebunny/crossref_metadata_2025 huggingface dataset:
A Parallel between Brownian Bridges and Gamma Bridges
Authors: Yor Marc , Émery Michel
Published: September 2006

Some properties of the
Gamma bridges
(obtained by conditioning the Gamma subordinator to take a given value at a given time) are investigated; similarities with the Brownian bridges are emphasized.
Toward the Exact WKB Analysis for Higher-Order Painlevé Equations — The Case of Noumi–Yamada Systems
Authors: Takei Yoshitsugu
Published: September 2006

As the ﬁrst step toward the exact WKB analysis for higher-order Painlevé equations, we study the Stokes geometry of the Noumi–Yamada system. It is shown that there are intriguing relations, similar to those for traditional Painlevé equations, between the Stokes geometry of the Noumi–Yamada system and that of its underlying Lax pair.
Crystal Bases for Quantum Classical Algebras and Nakajima’s Monomials
Authors: Kang Seok-Jin , Kim Jeong-Ah , Shin Dong-Uy
Published: September 2006

Using Nakajima’s monomials, we construct a new realization of crystal bases for ﬁnite dimensional irreducible modules over quantum classical algebras. We also give an explicit bijection between the monomial realization and the Young tableau realization of crystal bases.
A Cabling Formula for the 2-Loop Polynomial of Knots
Authors: Ohtsuki Tomotada
Published: September 2006

The 2-loop polynomial is a polynomial presenting the 2-loop part of the logarithm of the Kontsevich invariant of knots. We show a cabling formula for the 2-loop polynomial of knots. In particular, we calculate the 2-loop polynomial for torus knots.
String and Vortex
Authors: Kawai Toshiya
Published: September 2006

We discuss how the geometry of _D_2-_D_0 branes may be related to Gromov–Witten theory of Calabi–Yau threefolds.
Decomposition Problem on Endomorphisms of Projective Varieties
Authors: Fujimoto Yoshio
Published: September 2006

Let

Z := X × Y

be a product variety of nonsingular projective varieties

X

and

Y

. Suppose that

K_Y

is not nef but

K_X

is nef. The aim of this note is to study decomposition problems on an endomorphism

f : Z → Z

of

Z

.
A Serre-type Theorem for the Elliptic Lie Algebras with Rank $≥ 2$
Authors: Yamane Hiroyuki
Published: September 2006

In 2000, K. Saito and D. Yoshii gave a Serre-type theorem for the simply-laced elliptic Lie algebras. We extend the theorem to that for the elliptic Lie algebras associated with the (reduced marked) elliptic root systems with rank

≥ 2

.
Relations for Multiple Zeta Values and Mellin Transforms of Multiple Polylogarithms
Authors: Okuda Jun-ichi , Ueno Kimio
Published: September 2006

In this paper a relationship between the Ohno relation for multiple zeta values and multiple polylogarithms are discussed. First we introduce generating functions for the Ohno relation, and investigate their properties. We show that there exists a subfamily of the Ohno relation which recovers algebraically its totality. This is proved through analysis of Mellin transform of multiple polylogarithms. Furthermore, this subfamily is shown to be converted to the Landen connection formula for multiple polylogarithms by inverse Mellin transform.
Wegner Estimates and Localization for Gaussian Random Potentials
Authors: Ueki Naomasa
Published: September 2006

A Wegner estimate is proven for a Schr¨dinger operator with a bounded random o vector potential and a Gaussian random scalar potential. The estimate is used to prove the strong dynamical localization and the exponential decay of the eigenfunctions. For the proof, Klopp’s method using a vector ﬁeld on a probability space and Germinet and Klein’s bootstrap multiscale analysis are applied. Moreover Germinet and Klein’s characterization of the Anderson metal-insulator transport transition is extended to the above operator.
Fermionic Formulas for $(k, 3)$-admissible Conﬁgurations
Authors: Feigin Boris , Jimbo Michio , Miwa Tetsuji , Mukhin Evgeny , Takeyama Yoshihiro
Published: September 2006

We obtain the fermionic formulas for the characters of

(k,r)

-admissible conﬁgurations in the case of

r = 2

and

r = 3

. This combinatorial object appears as a label of a basis of certain subspace

W(Λ)

of level-

k

integrable highest weight module of

\widehat{\mathfrak{sl}}_r

. The dual space of

W(Λ)

is embedded into the space of symmetric polynomials. We introduce a ﬁltration on this space and determine the components of the associated graded space explicitly by using vertex operators. This implies a fermionic formula for the character of

W(Λ)

.
Particle Content of the $(\boldsymbol k, 3)$-conﬁgurations
Authors: Feigin Boris , Jimbo Michio , Miwa Tetsuji , Mukhin Evgeny , Takeyama Yoshihiro
Published: September 2006

For all

k

, we construct a bijection between the set of sequences of non-negative integers

\mathbf a = (a_i)_{i\in \mathbf Z_{≥0}}

satisfying

a_i + a_{i+1} + a_{i+2} ≤ k

and the set of rigged partitions

(λ,ρ)

. Here

λ = (λ_1, . . . , λ_n)

is a partition satisfying

k ≥ λ_1 ≥ · · · ≥ λ_n ≥ 1

and

ρ = (ρ_1, . . . , ρ_n ) \in \mathbf Z^n_{≥0}

is such that

ρ_j ≥ ρ_{j+1}

if

λ_j = λ_{j+1}

. One can think of

λ

as the particle content of the conﬁguration

\mathbf a

and

ρ_j

as the energy level of the

j

-th particle, which has the weight

λ_j

. The total energy

\sum_i ia_i

is written as the sum of the two-body interaction term

\sum_{j<j'} A_{λ_j,λ_j'}

and the free part

\sum_j ρ_j

. The bijection implies a fermionic formula for the one-dimensional conﬁguration sums

\sum_{\mathbf a}q^{\sum_i ia_i}

. We also derive the polynomial identities which describe the conﬁguration sums corresponding to the conﬁgurations with prescribed values for

a_0

and

a_1

, and such that

a_i = 0

for all

i > N

.
The Aron–Berner Extension for Polynomials Deﬁned in the Dual of a Banach Space
Authors: Llavona José G. , Moraes Luiza A.
Published: September 2006

Let

E = F'

where

F

is a complex Banach space and let

π_1 : E'' = E \oplus F^⊥ → E

be the canonical projection. Let

P({}^n E)

be the space of the complex valued continuous

n

-homogeneous polynomials deﬁned in

E

. We characterize the elements

P\in P({}^nE)

whose Aron–Berner extension coincides with

P\circ π_1

. The case of weakly continuous polynomials is considered. Finally we also study the same problem for holomorphic functions of bounded type.
Termination of 4-fold Canonical Flips
Authors: Fujino Osamu
Published: September 2006

There does not exist an inﬁnite sequence of 4-fold canonical ﬂips.
The Structure of Group $C^∗$-algebras of the Generalized Dixmier Groups
Authors: Sudo Takahiro
Published: September 2006

In this paper we ﬁrst analyze the algebraic structure of group

C^∗

-algebras of the generalized Dixmier groups, and next consider that of group

C^∗

-algebras of some Lie semi-direct products with multi-diagonal or diagonal actions. As an application, we estimate the stable rank and the connected stable rank of these

C^∗

-algebras in terms of groups. Also, we show that some of these group

C^∗

-algebras have no nontrivial projections.
Eigenvalue Asymptotics for the Schrödinger Operator with Steplike Magnetic Field and Slowly Decreasing Electric Potential
Authors: Shirai Shin-ichi
Published: September 2006

In this paper we consider the two-dimensional Schrödinger operator of the form:

H_V = − \frac{∂^2}{ ∂x_1^2} + \big( \frac 1 i \frac ∂ {∂x_2} − b(x_1)\big)^2 + V(x1, x2),

where the magnetic ﬁeld

B(x_1) = \mathrm{rot}(0, b(x_1))

is monotone increasing and steplike, namely the limits

\lim _{x_1 →±∞} B(x_1) = B_±

exist with

0 < B_− < B_+ < ∞

, and

V

is the slowly power-decaying electric potential. The spectrum

σ(H_0)

of the unperturbed operator

H_0

(

= H_V

with

V = 0

) has the band structure and

H_V

has the discrete spectrum in the gaps of the essential spectrum

σ_{\textit{ess}} (H_V) = σ(H_0)

. The aim of this paper is to study the asymptotic distribution of the eigenvalues near the edges of the spectral gaps. Using the min-max argument, we prove that the classical Weyl-type asymptotic formula is satisﬁed under suitable assumptions on

B

and

V

.
On a Certain Semiclassical Problem on Wiener Spaces
Authors: Aida Shigeki
Published: September 2006

We study asymptotic behavior of the spectrum of a Schrödinger type operator

L_V^λ = L − λ^2V

on the Wiener space as

λ → ∞

. Here

L

denotes the Ornstein–Uhlenbeck operator and

V

is a nonnegative potential function which has ﬁnitely many zero points. For some classes of potential functions, we determine the divergence order of the lowest eigenvalue. Also tunneling effect is studied.
The Poincaré Series of Some Special Quasihomogeneous Surface Singularities
Authors: Ebeling Wolfgang
Published: September 2006

In [E6] a relation is proved between the Poincaré series of the coordinate algebra of a two-dimensional quasihomogeneous isolated hypersurface singularity and the characteristic polynomial of its monodromy operator. We study this relation for Fuchsian singularities and show that it is connected with the mirror symmetry of K3 surfaces and with automorphisms of the Leech lattice. We also indicate relations between other singularities and Conway’s group.
Scattering Theory for a Stratiﬁed Acoustic Strip with Short- or Long-Range Perturbations
Authors: Croc Elizabeth , Iftimie Viorel
Published: September 2006

We consider the acoustic propagator

H= −∇ · ρ∇

acting in

L^2 (Ω)

with

Ω := Ω' × ℝ

and

Ω'

a bounded open set in

ℝ^{n−1}

,

n ≥ 2

. The real-valued function

ρ

belongs to

L^∞(Ω)

, and is bounded from below by

c > 0

. We assume there exist two strictly positive constants

c_1

and

c_2

and two perturbations,

δ^S

of short-range type and

δ^L

of long-range type, such that

ρ = c_j + δ^S + δ^L

on

Ω_j := \{(x'_n, xn) \in Ω|(−1)^j _n > 0\}

,

j = 1, 2

. We build two modiﬁed free evolutions

U_j(t)

,

j = 1, 2

, such that the wave operators

Ω^±_j := s − \lim_{t→±∞} e^{itH} U_j(t)

,

j = 1, 2

, exist and are asymptotically complete.
On the Micro-Hyperbolic Boundary Value Problem for Systems of Differential Equations
Authors: Uchida Motoo
Published: September 2006

We formulate the boundary value problem for systems of linear differential equations which satisfy a certain condition of micro-hyperbolicity at the boundary in the same way as the Kashiwara–Kawai formulation for elliptic systems.
State estimation and error diagnosis in industrial fed‐batch yeast fermentation
Authors: Hocalar A. , Türker M. , Öztürk S.
Published: September 2006

Measurements provide the basis for monitoring and control of industrial processes as well as model development and validation. Therefore, systematic approaches are of great value to increase accuracy and reliability of measurements. In bioprocesses, linear conservation relations such as elements and enthalpy can be employed to relate conversion rates. In this work, a systematic approach has been applied to production scale fed‐batch yeast fermentations. The six data sets obtained from two industrial size bubble columns, one with 25 m3 volumes and the other with 100 m3 volumes, are analyzed for state estimation and error diagnosis. A statistical test is employed for error diagnosis. The serial elimination method is used to analyze and locate the source of errors. The conversion rates are calculated from primary measurements such as flow rates, temperatures, and concentrations. When available measurements are more than the degrees of freedom of the system, it is said that the system is redundant. The redundancy is, therefore, used for error detection and data reconciliation for the six data sets in this work. In addition to elemental balances, heat balance has been set up for the bubble columns, and metabolic heat production rate is employed as an additional measurement. The redundancy is employed for state estimation, and biomass concentration and specific growth rate have been estimated with great accuracy. The estimations can be further used for process monitoring and control. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Case‐control and within‐family tests for an association between conduct disorder and 5HTTLPR
Authors: Sakai Joseph T. , Young Susan E. , Stallings Michael C. , Timberlake David , Smolen Andrew , Stetler Gary L. , Crowley Thomas J.
Published: September 2006

Several lines of research have suggested that serotonin dysfunction is associated with aggression, impulsivity, and antisocial behavior. A functional polymorphism in the promoter region (s, short and l, long allele variant) of the serotonin transporter gene (SLC6A4) that results in decreased transcription of the serotonin transporter gene has been linked with such serotonin dysfunction. To test for an association between 5HTTLPR genotype and conduct disorder diagnosis/aggression. Analysis for association between 5HTTLPR and conduct disorder/aggression using a case‐control design and the transmission disequilibrium test. Conduct‐disordered adolescents, who were drawn from admissions to a program that treats adolescents with serious substance and behavior problems, and conduct‐disordered siblings of these patients (n, 297) were compared with non‐conduct‐disordered control adolescents and non‐conduct‐disordered siblings of these controls (n, 93). Second, using patient families where parental DNA was available, transmission disequilibrium tests were conducted for two phenotypes: (1) conduct disorder (74 trios), and (2) conduct disorder with at least one aggressive symptom (57 trios). Case‐control analyses suggested a strong association between the ss genotype and conduct disorder (χ = 14.3; P < 0.01). Within‐family analyses for conduct disorder with at least one aggressive symptom significantly favored greater transmission of the s‐allele to affected offspring (χ = 4.13; P = 0.04); for conduct disorder, without aggressive symptoms, however, results were non‐significant (χ = 1.61; P = 0.20). These data suggest that the s‐allele may confer some risk for aggressive behavior or may be in linkage disequilibrium with such an allele. © 2006 Wiley‐Liss, Inc.
Density Functional Embedded Cluster Study of Cu4, Ag4 and Au4 Species Interacting with Oxygen Vacancies on the MgO(001) Surface
Authors: Neyman Konstantin M. , Inntam Chan , Moskaleva Lyudmila V. , Rösch Notker
Published: September 2006

Cu4, Ag4, and Au4 species adsorbed on an MgO(001) surface that exhibits neutral (Fs) and charged (Fs+) oxygen vacancies have been studied using a density functional approach and advanced embedding models. The gas‐phase rhombic‐planar structure of the coinage metal tetramers is only moderately affected by adsorption. In the most stable surface configuration, the plane of the tetramers is oriented perpendicular to the MgO(001) surface; one metal atom is attached to an oxygen vacancy and another one is bound to a nearby surface oxygen anion. A very similar structural motif was recently found on defect‐free MgO(001), where two O2− ions serve as adsorption sites. Following the trend of the interactions with the regular MgO(001) surface, Au4 and Cu4 bind substantially stronger to Fs and Fs+ sites than Ag4. This stronger adsorption interaction at oxygen vacancies, in particular at Fs, is partly due to a notable accumulation of electron density on the adsorbates. We also examined the propensity of small supported metal species to aggregate to adsorbed di‐, tri‐ and tetramers. Furthermore, we demonstrated that core‐level ionization potentials offer the possibility for detecting experimentally supported metal tetramers and characterizing them structurally with the help of calculated data.
Polymer Matrix Effects on the Nonlinear Optical Response of Incorporated Chromophore: New Analytical Models
Authors: Balakina Marina Yu.
Published: September 2006

A new approach aimed at the modeling of the nonlinear optical (NLO) response of a dipole chromophore incorporated into a locally anisotropic, deformable, polarizable polymer matrix is suggested. The general continuum methodology is used with a specific cavity ansatz being employed; the cavity is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the polymer medium. The suggested ansatz allows the electrostatic boundary value problem to be solved analytically, and the local field experienced by the chromophore in the polymer electret to be found. Four analytically solvable models, which correspond to two singular and two nonsingular models, are considered; in two of them the chromophore is characterized by singular dipole and quadrupole moments; the other two use the approximation of the electric moment of the chromophore with that of the polarized ellipsoid. The relation between the macroscopic polymer properties and the microscopic characteristics of the NLO chromophore is established. The compliance of the obtained formulas for the local field with those of the classical Onsager approach is analyzed, and their specific features are considered.
Evolution of arthropod visual systems: Development of the eyes and central visual pathways in the horseshoe crab Limulus polyphemus Linnaeus, 1758 (Chelicerata, Xiphosura)
Authors: Harzsch Steffen , Vilpoux Kathia , Blackburn David C. , Platchetzki David , Brown Nadean L. , Melzer Roland , Kempler Karen E. , Battelle Barbara A.
Published: September 2006

Dorsal view of a larva of the horseshoe crab Limulus polyphemus (Chelicerata, Xiphosura) showing the paired lateral eyes and the median eyes. See Harzsch et al., Developmental Dynamics 235:2641–2655.
Equivalent inductance of power‐distribution planes in multilayer printed circuit boards and capacitor allocation for decoupling
Authors: Harada Takashi , Kobayashi Naoki
Published: September 2006

In order to obtain a design guideline related to the optimum allocation of decoupling capacitor to reduce unwanted electromagnetic wave radiation due to voltage variation and to supply the charge needed for chip operation in a multilayered printed circuit board, the equivalent inductance of the power distribution system is quantitatively analyzed. The power distribution system is represented by a two‐dimensional equivalent circuit network and is analyzed. It is found that the parasitic inductance becomes smaller as the distance between the power distribution plane and the ground plane decreases. Further, this result is applied to optimum allocation of the capacitor near the LSI power distribution pin for suppression of LSI malfunctions and to quantification of the radiation suppression effect of capacitor allocation near the via hole that is generated in the interconnect processing of the signal pattern through the power distribution plane and the ground plane. The relationship of the spacing between the planes to the distance between the power distribution pin and the capacitor is formulated so as to keep the power distribution voltage variations within a certain range. Also formulated is the relationship of the radiation suppression effect to the distance between the via hole and the capacitor location in order to obtain constant radiation suppression efficiency. In this way, specific design values of capacitor allocation are obtained for suppression of LSI malfunctions and unwanted electromagnetic radiation. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(10): 27–35, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20154
An acetylene (13 C2H2) stabilized single‐polarization fiber laser
Authors: Kasai Keisuke , Yoshida Masato , Nakazawa Masataka
Published: September 2006

In this paper, we report on a nonmodulated output‐type frequency stabilized fiber laser that uses an absorption line of the acetylene molecule. First, in this fiber laser, a single‐frequency oscillation was formed by inserting into the resonator a 3.7‐GHz super‐narrow‐band optical filter that uses a fiber Bragg grating (FBG). Next, fully 2‐GHz continuous tuning of the oscillation frequency was achieved by tuning while synchronizing the central frequency of the FBG and the laser resonance frequency. We succeeded in stabilizing the oscillation frequency of this laser at a linear absorption line of the molecule (line width approximately 700 MHz) of an acetylene absorption cell set up externally. The stability of the optical frequency estimated from the error signal (Allan variance) was highly stable, namely, 1.7×10−10 for an integration time of 1 s and 1.7×10−11 for 102s. Its oscillation linewidth was approximately 6 kHz, and thus a narrow‐linewidth single‐polarization frequency‐stabilized laser was realized. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(10): 9–17, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20235
Balance type pair transmission line for 60‐GHz band using multi‐layer substrate
Authors: Nakase Hiroyuki , Oshima Shoichi , Fujii Takashi , Kameda Suguru , Isota Yoji , Tsubouchi Kazuo
Published: September 2006

For a high‐density multilayer substrate ALIVH, balanced pair transmission lines on which 60‐GHz signals can be transmitted are proposed. First, it is shown that transmission of millimeter wave signals is difficult due to impedance mismatch of the vias in the conventional unbalanced transmission lines. Further, it is shown that transmission at up to 90 GHz is possible by a design such that the microstrip line on the surface, the strip line in the inner layer, and the vias connecting each layer have the same transmission line spacing and the same characteristic impedance. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(10): 1–8, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20249
Uncalibrated 3D visual servoing from projective reconstruction of control values
Authors: Adachi Jun , Sato Jun
Published: September 2006

Visual servoing has been widely studied as a robust method for controlling a robot that can deal with unpredictable disturbances. However, existing visual servoing methods require that the robot and camera be calibrated in advance. Although the current authors have previously proposed an uncalibrated visual servoing method that does not require the camera and robot to be calibrated, the starting position of the robot had a large influence on the control process in that method. This paper presents an uncalibrated visual servoing method that can control a robot in the same way from any starting position by determining control values without uncertainty in the magnitude. In particular, it is demonstrated that a robot can be accurately guided to a target position by using projective reconstruction, which has been studied extensively in recent years in the field of computer vision, by introducing the concept of the projection of control values. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(10): 47–56, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20314
Morphology Control of CdSe Submicrostructures with High Hierarchy in Solution
Authors: Li Benxia , Jing Meng , Rong Guoxin , Xu Yang , Xie Yi
Published: September 2006

A series of CdSe submicrostructures, including rods, fringy structures, and fasciculate tubes with high hierarchy, have been selectively prepared by a facile one‐step solution‐based strategy without using any organic surfactants, simply by changing the feeding quantity of aqueous ammonia (25 % NH3). The growth mechanism based on kinetic control is discussed for the selective formation of the CdSe submicrostructures with special morphologies. In the present reaction system, ammonia plays a dual role: providing an alkaline medium for the formation of Se2– and acting as a coordinating agent for cadmium cations in either the solution or the solid phase. The feeding quantity of aqueous ammonia greatly influences the rate of formation of the Se2– anion, and thus determines the final morphology of CdSe crystals. Compared with previous methods of preparing CdSe structures, this concise and novel one‐step route has special advantages, suggesting a new path for convenient synthesis of CdSe materials with novel morphology. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Structural Characterization of a New Alkaline Earth Imide: MgCa(NH)2
Authors: Liu Yongfeng , Liu Tao , Xiong Zhitao , Hu Jianjiang , Wu Guotao , Chen Ping , Wee Andrew T. S. , Yang Ping , Murata Kenji , Sakata Ko
Published: September 2006

The ternary imide of MgCa(NH)2 has been successfully synthesized for the first time by the mechanochemical reaction of Mg(NH2)2 and CaH2 at a molar ratio of 1:1. It was found that ca. four H atoms were desorbed per Mg(NH2)2‐CaH2 after 72 h of ball milling leaving a solid residue with the chemical composition of MgCa(NH)2. The solid residue exhibits an imide N–H stretching vibration at 3151 cm–1 and a cubic CaNH‐like structure. In addition, X‐ray Absorption Fine Structure examination at the Ca K‐edge indicates that six N atoms occupy the first coordination shell of the Ca center in an anticipated octahedral geometry, and Ca(Mg) atoms occupy the second coordination shell. The distances of Ca–N and Ca–Ca(Mg) in the newly formed MgCa(NH)2 structure calculated by ESDs are 2.46 and 3.47 Å, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
An Unusual Reaction of (β‐Dimethylaminoethoxy)triethyltin with Phenyltin Trichloride. The First X‐ray Structural Evidence of the Existence of Complexes R2SnXY·R2SnXY (R = Alkyl, Aryl; X, Y = Hal, OR, X ≠ Y) Both as Unsymmetrical Adducts [R2SnX2·R2SnY2] and Symmetrical Dimers [R2SnXY]2
Authors: Portnyagin Ivan A. , Nechaev Mikhail S. , Khrustalev Victor N. , Zemlyansky Nikolay N. , Borisova Irina V. , Antipin Mikhail Yu. , Ustynyuk Yuri A. , Lunin Valery V.
Published: September 2006

The substituent exchange reaction of PhSnCl3 with [Et3Sn(OCH2CH2NMe2)] gives rise unexpectedly to the unsymmetrical adduct [Ph2SnCl2·Ph2Sn(OCH2CH2NMe2)2] (2). It has been unambiguously proved for the first time that compounds of the RSnX3 type are able to undergo the hydrocarbon substituent redistribution reaction. The analogous tin complexes [Et2SnCl2·Et2Sn(OMe)2] (5) and [Bu2Sn(OAc)2·Bu2Sn(OMe)2] (6), which have ligands other than β‐dimethylaminoethoxy and could be considered as “organotin analogs of Grignard reagents” have symmetrical dimeric structures, i.e., can be formulated as [Bu2Sn(OMe)(OAc)]2 and [Et2Sn(OMe)Cl]2, respectively. Both types of structures, viz., unsymmetrical adduct (2) and symmetrical dimer (5, 6), have been characterized by X‐ray diffraction analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
DFT Investigation of the Potential of [H‐M{(NHCH2CH2)3X}] Catalysts (M = Mo, Ru, Os; X = N, P) for the Reduction of N2 to NH3 by H2
Authors: Hölscher Markus , Leitner Walter
Published: September 2006

DFT calculations of model complexes [H‐M{(NHCH2CH2)3X}] (M = Mo, Ru, Os; X = N, P) were carried out to investigate the catalytic potential of these complexes towards the reduction of N2 to NH3 using only H2 as the reducing agent. Closed catalytic cycles were calculated for all three metal hydrides. The calculations showed that [H‐Mo{(NHCH2CH2)3N}], 1‐Mo, is not an appropriate catalyst due to very high activation barriers for several steps of the reaction (ΔH‡max = 69.1 kcal/mol). Much lower activation barriers were found for the Ru and Os catalysts [H‐Ru{(NHCH2CH2)3N}], 1‐Ru, and [H‐Os{(NHCH2CH2)3P}], 1‐Os(P). With ΔH‡max/ΔG‡max = 29.3/35.7 kcal/mol, 1‐Os(P) shows potential for future theoretical work. QM/MM calculations were used to investigate some properties of the Ru system empolying the hexaisopropylterphenyl ligand (HIPT). The results indicate that an HIPT substituent at the ligand core has a benefical influence on some reaction steps by lowering the activation barriers, while for other steps the activation energies increase. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Narrowband PPM semi‐‘blind’ spatial‐rake receiver & co‐channel interference suppression
Authors: Wong Kainam Thomas
Published: September 2006

Among the open‐literature on pulse‐position‐modulation (PPM) radiowave wireless communications, this work is first to advance a semi‐‘blind’/‘blind’ spatial‐rake receiver with interference‐rejection capability. This proposed adaptive ‘smart antennas’ detector uses the signal‐of‐interest's (SOI) earlier decoded information‐symbols to segment earlier collected data into two data‐groups: one data‐group with the SOI and co‐channel‐interference and noise, with the other data‐group containing only the latter two. These two data‐groups' spatial‐correlation matrices' generalised‐eigenvector maximises the ‘blind’ spatial beamformer's output signal‐to‐interference‐and‐noise ratio (SINR) withoutprior knowledge of (1) the multi‐access user interferers' (MAUI) arrival directions, delays nor powers, (2) the signal‐of‐interest's (SOI) spatial signature at the receiving sensor‐array, and (3) the mobile's receiving‐antennas' nominal/actual array‐geometry and gain/phase responses. This proposed scheme is semi‐‘blind’ because it needs a pilot sequence from the SOI.

This means that the fading may be, but needs not be, statistically uncorrelated across the antennas in the mobile receiver.

Copyright © 2006 AEIT
Signaling pathways of LIGHT induced macrophage migration and vascular smooth muscle cell proliferation
Authors: Wei Chun‐Yu , Chou Yin‐Hsiang , Ho Feng‐Ming , Hsieh Shie‐Liang , Lin Wan‐Wan
Published: September 2006

The biological actions of LIGHT, a member of the tumor necrosis factor superfamily, are mediated by the interaction with lymphotoxin‐β receptor (LTβR) and/or herpes virus entry mediator (HVEM). Previous study demonstrated high‐level expressions of LIGHT and HVEM receptors in atherosclerotic plaques. To investigate the role of LIGHT in the functioning of macrophages and vascular smooth muscle cells (VSMC) in relation to atherogenesis, we determined the effects of LIGHT on macrophage migration and VSMC proliferation. We found LIGHT through HVEM activation can induce both events. LIGHT‐induced macrophage migration was associated with activation of signaling kinases, including MAPKs, PI3K/Akt, NF‐κB, Src members, and FAK. Proliferation of VSMC was also shown relating to the activation of MAPKs, PI3K/Akt, and NF‐κB, which consequently led to alter the expression of cell cycle regulatory molecules. Down‐regulation of p21, p27, and p53, and inversely up‐regulation of cyclin D and RB hyper‐phosphorylation were demonstrated. In conclusion, LIGHT acts as a novel mediator for macrophage migration and VSMC proliferation, suggesting its involvement in the atherogenesis. J. Cell. Physiol. 209: 735–743, 2006. © 2006 Wiley‐Liss, Inc.
Extracellular adenosine triphosphate protects oxidative stress‐induced increase of p21WAF1/Cip1 and p27Kip1 expression in primary cultured renal proximal tubule cells: Role of PI3K and Akt signaling
Authors: Lee Yun Jung , Lee Jang Hern , Han Ho Jae
Published: September 2006

Oxidative stress, the result of cellular production of reactive oxygen species (ROS), has been implicated in causing many renal diseases. Adenosine triphosphate (ATP) is an important extracellular signal in the regulation of many intracellular processes in normal tubular cells as well as in the pathogenesis of cell injury. This study investigated the effect of ATP on H2O2‐induced increase of cyclin kinase inhibitors (CKI) expression and its related signal molecules in primary cultured renal proximal tubule cells (PTCs). H2O2 inhibited DNA synthesis in a concentration‐ (>50 µM) and time‐dependent manner (>2 h), as determined by thymidine and BrdU incorporation, and by increase in the p21WAF/Cip1 and p27Kip1 expression levels. In contrast, ATP increased the level of thymidine, BrdU incorporation (>10−5 M), and decreased the p21WAF/Cip1 and p27Kip1 expression levels, suggesting that ATP has a protective effect against H2O2‐induced oxidative damage. Suramin, reactive blue 2 (RB‐2), MRS 2159, and MRS 2179 did block the reversing effect of ATP. In addition, AMP‐CPP or 2‐methylthio‐ATP blocked H2O2‐induced inhibition of DNA synthesis, suggesting all these P2 purinoceptors may be potentially involved. ATP‐induced stimulation of DNA synthesis was blocked by phosphatidylinositol 3‐kinase (PI3K) and Akt inhibitors. These results suggest the involvement of P2 purinoceptors‐mediated PI3K/Akt signal pathway in the protective effect of ATP against H2O2‐induced oxidative damage. Indeed, pre‐treatment with PI3K or Akt inhibitors did not protect H2O2‐induced lipid peroxide (LPO) production and inhibition of thymidine incorporation. In conclusion, ATP, in part, blocked H2O2‐induced increase of p21WAF1/Cip1 and p27Kip1 expression through PI3K and Akt signal pathway in renal PTCs. J. Cell. Physiol. 209: 802–810, 2006. © 2006 Wiley‐Liss, Inc.
Signaling networks from Gβ1 subunit to transcription factors and actin remodeling via a membrane‐located ERβ‐related protein in the rapid action of daidzein in osteoblasts
Authors: De Wilde Anne , Heberden Christine , Chaumaz Gilles , Bordat Christian , Lieberherr Michele
Published: September 2006

Although estrogen replacement has been the main therapy to prevent and treat osteoporosis, there are concerns about its safety. Phytoestrogens have attracted attention to their potential impacts in osteoporosis prevention and treatment. Among phytoestrogens, the isoflavone daidzein (Dz) acts on transcription via the intracellular estrogen receptors (ER), mainly ERβ, in osteoblasts, but mimics only part of the estrogen effects. Since estradiol also exerts rapid effects in osteoblasts, we investigated the multistep processes involved in the rapid actions of low (1–100 pM) doses of daidzein. Dz bound to a membrane moiety, related to ERβ since the calcium response to Dz was blocked by an anti‐ERβ antibody directed against the C‐terminus, but not by a double‐stranded siRNA specific for ERβ. This protein was coupled to a pertussis toxin (PTX)‐sensitive Gβ1 subunit whose transducer was PLC‐β2, which triggered a rapid (5 sec) mobilization of calcium from the endoplasmic reticulum. Dz phosphorylated within 15 sec ERK1/2 whose phosphorylation involved two routes: Gβ1/PLC‐β2/PKC/c‐Raf‐1/MEK1/2 and Gβ1/PI3K/cSrc/c‐Raf‐1/MEK1/2 as shown using several inhibitors. Dz induced rapid (1 min) changes in the actin cytoskeleton via the two routes. The rapid (20 sec) phosphorylation of Elk‐1 and CREB by Dz involved Gβ1 and ERK1/2. All the processes were insensitive to the estradiol antagonist ICI 182,780. In conclusion, the rapid effects of Dz seem to be biologically relevant for the function of osteoblast in bone since the isoflavone activates transcription factors linked to early genes controlling cellular proliferation and differentiation, and modulates actin cytoskeleton which controls cell adhesion, division, or secretion. J. Cell. Physiol. 209: 786–801, 2006. © 2006 Wiley‐Liss, Inc.
N‐(4‐hydroxyphenyl)retinamide induces apoptosis in human retinal pigment epithelial cells: Retinoic acid receptors regulate apoptosis, reactive oxygen species generation, and the expression of heme oxygenase‐1 and Gadd153
Authors: Samuel William , Kutty R. Krishnan , Nagineni Sahrudaya , Vijayasarathy Camasamudram , Chandraratna Roshantha A.S. , Wiggert Barbara
Published: September 2006

N‐(4‐hydroxyphenyl)retinamide (4HPR, fenretinide), a retinoic acid (RA) derivative and a potential cancer preventive agent, is known to exert its chemotherapeutic effects in cancer cells through induction of apoptosis. Earlier work from our laboratory has shown that relatively low concentrations of 4HPR induce neuronal differentiation of cultured human retinal pigment epithelial (ARPE‐19) cells (Chen et al., 2003, J Neurochem 84:972–981). However, at higher concentrations of 4HPR, these cells showed morphological changes including cell shrinkage and cell death. Here we demonstrate that ARPE‐19 cells treated with 4HPR exhibit a dose‐ and time‐dependent induction of apoptosis as evidenced by morphological changes, mono‐ and oligonucleosome generation, and increased activity of caspases 2 and 3. The 4HPR‐induced apoptosis as well as the activation of caspases 2 and 3 were blocked by both retinoic acid receptors (RAR) pan‐antagonists, AGN193109 and AGN194310, and by an RARα‐specific antagonist AGN194301. 4HPR treatment also increased reactive oxygen species (ROS) generation in ARPE‐19 cells in a time‐dependent manner as determined from the oxidation of 2′,7′‐dichlorofluorescin. In addition, the increase in the expression of heme oxygenase‐1 (HO‐1), a stress response protein, and the growth arrest and DNA damage‐inducible transcription factor 153 (Gadd153) in response to the ROS generation were also blocked by these receptor antagonists. Pyrrolidine dithiocarbamate (PDTC), a free‐radical scavenger, inhibited 4HPR‐induced ROS generation, the expression of its downstream mediator, Gadd153, and apoptosis in the pretreated cells. Therefore, our results, clearly demonstrate that 4HPR induces apoptosis in ARPE‐19 cells and that RARs mediate this process by regulating ROS generation as well as the expression of Gadd153 and HO‐1. J. Cell. Physiol. 209: 854–865, 2006. © 2006 Wiley‐Liss, Inc.
Self‐renewal of human embryonic stem cells is supported by a shortened G1 cell cycle phase
Authors: Becker Klaus A. , Ghule Prachi N. , Therrien Jaclyn A. , Lian Jane B. , Stein Janet L. , van Wijnen Andre J. , Stein Gary S.
Published: September 2006

Competency for self‐renewal of human embryonic stem (ES) cells is linked to pluripotency. However, there is a critical paucity of fundamental parameters of human ES cell division. In this study we show that human ES cells (H1 and H9; NIH‐designated WA01 and WA09) rapidly proliferate due to a very short overall cell cycle (15–16 h) compared to somatic cells (e.g., normal diploid IMR90 fibroblasts and NT‐2 teratocarcinoma cells). The human ES cell cycle maintains the four canonical cell cycle stages G1, S, G2, and M, but the duration of G1 is dramatically shortened. Bromodeoxyuridine (BrdU) incorporation and FACS analysis demonstrated that 65% of asynchronously growing human ES cells are in S phase. Immunofluorescence microscopy studies detecting BrdU labeled mitotic chromosomes, Ki67 domains, and p220NPAT containing Cajal bodies revealed that the durations of the S (∼8 h), G2 (∼4 h), and M phases (∼1 h) are similar in ES and somatic cells. We determined that human ES cells remain viable after synchronization with either nocodazole or the anti‐tumor drug Paclitaxel (taxol) and have an abbreviated G1 phase of only 2.5–3 h that is significantly shorter than in somatic cells. Molecular analyses using quantitative RT‐PCR demonstrate that human ES cells and somatic cells express similar cell cycle markers. However, among cyclins and cyclin‐dependent kinases (CDKs), we observed high mRNA levels for the G1‐related CDK4 and cyclin D2 genes. We conclude that human ES cells exhibit unique G1 cell cycle kinetics and use CDK4/cyclin D2 related mechanisms to attain competency for DNA replication. J. Cell. Physiol. 209: 883–893, 2006. © 2006 Wiley‐Liss, Inc.
Long‐term loading inhibits ERK1/2 phosphorylation and increases FGFR3 expression in MC3T3‐E1 osteoblast cells
Authors: Jackson Rebecca A. , Kumarasuriyar Arjuna , Nurcombe Victor , Cool Simon M.
Published: September 2006

Bone tissue homeostasis relies upon the ability of cells to detect and interpret extracellular signals that direct changes in tissue architecture. This study utilized a four‐point bending model to create both fluid shear and strain forces (loading) during the time‐dependent progression of MC3T3‐E1 preosteoblasts along the osteogenic lineage. Loading was shown to increase cell number, alkaline phosphatase (ALP) activity, collagen synthesis, and the mRNA expression levels of Runx2, osteocalcin (OC), osteopontin, and cyclo‐oxygenase‐2. However, mineralization in these cultures was inhibited, despite an increase in calcium accumulation, suggesting that loading may inhibit mineralization in order to increase matrix deposition. Loading also increased fibroblast growth factor receptor‐3 (FGFR3) expression coincident with an inhibition of FGFR1, FGFR4, FGF1, and extracellular signal‐related kinase (ERK)1/2 phosphorylation. To examine whether these loading‐induced changes in cell phenotype and FGFR expression could be attributed to the inhibition of ERK1/2 phosphorylation, cells were grown for 25 days in the presence of the MEK1/2 inhibitor, U0126. Significant increases in the expression of FGFR3, ALP, and OC were observed, as well as the inhibition of FGFR1, FGFR4, and FGF1. However, U0126 also increased matrix mineralization, demonstrating that inhibition of ERK1/2 phosphorylation cannot fully account for the changes observed in response to loading. In conclusion, this study demonstrates that preosteoblasts are mechanoresponsive, and that long‐term loading, whilst increasing proliferation and differentiation of preosteoblasts, inhibits matrix mineralization. In addition, the increase in FGFR3 expression suggests that it may have a role in osteoblast differentiation. J. Cell. Physiol. 209: 894–904, 2006. © 2006 Wiley‐Liss, Inc.
Human articular chondrocytes suppress in vitro proliferation of anti‐CD3 activated peripheral blood mononuclear cells
Authors: Bocelli‐Tyndall Chiara , Barbero Andrea , Candrian Christian , Ceredig Rhodri , Tyndall Alan , Martin Ivan
Published: September 2006

Objective: To investigate whether mature human articular chondrocytes (AC) exhibit an antiproliferative effect on activated peripheral blood mononuclear cells (PBMC) and to compare this effect with other cells of mesenchymal origin. Methods: AC from healthy cadaveric cartilage were grown for different passages, in the absence (control) or presence of factors enhancing cell de‐differentiation (transforming growth factor (TGF)β1, fibroblast growth factor (FGF)‐2, and platelet derived growth factor (PDGF)bb‐TFP medium). Cell ability to suppress PBMC proliferation driven by anti‐CD3 antibody was measured by tritiated thymidine uptake following incubation for 48 h at different PBMC:AC ratios and expressed as percent of residual proliferation (RP). AC antiproliferative effect was compared to that of control dermal fibroblasts (DF) and bone marrow stromal cells (BMSC). Results: AC exhibited a cell number‐dependent antiproliferative effect. The strongest effect (up to 2% RP) was measured using the least expanded AC cultures. The use of TFP medium for AC expansion resulted in a significantly lower antiproliferative effect, in the range of that induced by BMSC (up to 18% RP). Also DF induced a marked antiproliferative effect (up to 11% RP). Conclusion: We report for the first time that human AC have a marked antiproliferative effect on anti‐CD3 stimulated PBMC, which is reduced upon culture in medium‐inducing extensive cell de‐differentiation. These results reflect the immunosuppressive properties observed for other different mesenchymal cell types and raise the question of a potential common physiological role in local tissue protection. J. Cell. Physiol. 209: 732–734, 2006. © 2006 Wiley‐Liss, Inc.
α2β1 integrin signalling enhances cyclooxygenase‐2 expression in intestinal epithelial cells
Authors: Broom Oliver Jay , Massoumi Ramin , Sjölander Anita
Published: September 2006

Inflammatory bowel diseases (IBD) are linked to an increased risk of developing colon cancer, by inflammatory mediators and alterations to the extracellular matrix (ECM). The events induced by inflammatory mediators lead to dysregulated activation and induction of inflammatory genes such as cyclooxygenase‐2 (COX‐2). COX‐2 is involved in the conversion of arachidonic acid to biologically active prostanoids and is highly upregulated in colon cancer. Since inflammation‐induced changes to the extracellular matrix could affect integrin activities, we here investigated the effect of integrin signalling on the level of COX‐2 expression in the non‐transformed intestinal epithelial cell lines, Int 407 and IEC‐6. Adhesion of these cells to a collagen I‐ or IV‐coated surface, increased surface expression of α2β1 integrin. Activation of integrins with collagen caused an increased cox‐2 promoter activity, with a subsequent increase in COX‐2 expression. The signalling cascade leading to this increased expression and promoter activity of cox‐2, involves PKCα, the small GTPase Ras and NFκB but not Erk1/2 or Src activity. The integrin‐induced increase in cellular COX‐2 activity is responsible for an elevated generation of reactive oxygen species (ROS) and increased cell migration. This signalling pathway suggests a mechanism whereby inflammation‐induced modulations of the ECM, can promote cancer transformation in the intestinal epithelial cells. J. Cell. Physiol. 209: 950–958, 2006. © 2006 Wiley‐Liss, Inc.
Acute loss of transcription factor E2F1 induces mitochondrial biogenesis in Hela cells
Authors: Goto Yuya , Hayashi Reiko , Kang Dongchon , Yoshida Kenichi
Published: September 2006

Here, we sought to clarify the comprehensive cellular response to transcription factor E2F1 expression using short interfering RNA (siRNA)‐mediated gene silencing to examine the roles of E2F1. For this purpose, we analyzed global gene expression changes in E2F1 knockdown HeLa cells, where no changes in cell growth or apoptosis were observed. Among the identified genes, the mRNA levels of mitochondria‐encoded genes were highly elevated in E2F1 siRNA‐treated cells, but not in E2F6 siRNA‐treated cells, relative to control siRNA‐treated cells. These changes were accompanied by a significant increase in the transcription and replication of mitochondria DNA as well as the induction of nuclear‐encoded mitochondrial topoisomerase I (TOP1MT) mRNA in E2F1 knockdown cells, but not in E2F6 knockdown cells, whereas the levels of nuclear‐encoded mitochondrial transcription factor A (TFAM) mRNA and protein were unchanged, relative to the levels in control siRNA‐treated cells. Time‐course experiments demonstrated that the induction of TOP1MT coincided with the timing of E2F1 loss. In addition, E2F1 knockdown cells, but not E2F6 knockdown cells, displayed increased ATP levels along with an accumulation of cytochrome b protein. Finally, RNA interference (RNAi)‐mediated reduction in E2F1 knockdown HeLa cells, but not in E2F6 knockdown HeLa cells, resulted in increased anticancer drug sensitivity. Taken together, these data demonstrate a novel physiological aspect of E2F1 in human cancer cells, where activated mitochondrial biogenesis occurs as a consequence of the acute loss of E2F1. J. Cell. Physiol. 209: 923–934, 2006. © 2006 Wiley‐Liss, Inc.
Peroxisome proliferator‐activated receptor (PPAR)γ is expressed by human spermatozoa: Its potential role on the sperm physiology
Authors: Aquila Saveria , Bonofiglio Daniela , Gentile Mariaelena , Middea Emilia , Gabriele Sabrina , Belmonte Maria , Catalano Stefania , Pellegrino Michele , Andò Sebastiano
Published: September 2006

The peroxisome proliferation‐activated receptor gamma (PPARγ) is mainly expressed in the adipose tissue and integrates the control of energy, lipid, and glucose homeostasis. The present study, by means of RT‐PCR, Western blot, and immunofluorescence techniques, demonstrates that human sperm express the PPARγ. The functionality of the receptor was evidenced by 15‐deoxy‐12,14‐prostaglandin J2 (PGJ2) and rosiglitazone (BRL) PPARγ‐agonists that were tested on capacitation, acrosome reaction, and motility. Both treatments also increase AKT phosphorylations and influence glucose and lipid metabolism in sperm. The specificity of PGJ2 and BRL effects through PPARγ on human sperm was confirmed by an irreversible PPARγ antagonist, GW9662. Our findings provide evidence that human sperm express a functional PPARγ whose activation influences sperm physiology. In conclusion, the presence of PPARγ in male gamete broadens the field of action of this nuclear receptor, bringing us to look towards sperm as an endocrine mobile unit independent of the systemic regulation. J. Cell. Physiol. 209: 977–986, 2006. © 2006 Wiley‐Liss, Inc.