bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of promoter sequence on transient expression of the β-glucuronidase gene in embryogenic calli of Larix × eurolepis and Picea mariana following microprojection
Authors: Duchesne Luc C. , Charest Pierre J.
Published: December 2007

The transient expression of the β-glucuronidase reporter gene was compared in embryogenic cell lines of Larix × eurolepis (L. decidua × L. leptolepis) and Picea mariana after introduction of eight vectors containing different promoter sequences using the Dupont Biolistic™ particle delivery system. Transient β-glucuronidase gene expression was highest in cells of both species after bombardment using the wheat abscisic acid inducible Em gene promoter. Transient β-glucuronidase gene expression was comparable in P. mariana and L. × eurolepis for all vectors, with the exception of the rice actin promoter that yielded higher activity in P. mariana than in L. × eurolepis. The Em gene promoter proved inducible by abscisic acid; upon the addition of abscisic acid to the culture medium, β-glucuronidase gene expression was increased 2.3- and 4.4-fold for L. × eurolepis and P. mariana, respectively. Investigation of β-glucuronidase gene expression over time showed that all transient activity disappeared 16 days after microprojection. Key words: Larix, Picea, transformation, β-glucuronidase, tissue cultures.
Effects of nitrogen fertilization and photoperiod on basidiome formation of Laccaria bicolor associated with container-grown jack pine seedlings
Authors: Godbout Christian , Fortin J. André
Published: December 2007

Container-grown jack pine (Pinus banksiana) seedlings were inoculated with a wild strain of the ectomycorrhizal fungus Laccaria bicolor. Seedlings were raised for 24 weeks and were given various nitrogen fertilization levels as well as long and short day regimes. Basidiomes occurred from week 16 up to the end of the experiment (24 weeks) depending on the culture conditions. Frequency of fruiting reached a maximum with the addition of 5 – 6 mg of nitrogen per seedling. The response of fruiting to nitrogen was enhanced with a short photoperiod. The biomass of the basidiomes was positively correlated with the biomass of their respective host plants with proportions ranging from 10 to 35% and with a mean of 20%. Key words: basidiome, Laccaria bicolor, fertilization, photoperiod, ectomycorrhiza.
Response of peach bark tissues to inoculation with epiphytic fungi alone and in combination with Leucostoma cincta
Authors: Biggs A. R. , Alm G. R.
Published: December 2007

Wounded peach bark was inoculated with the fungal epiphytes Alternaria alternata (Fr.:Fr.) Keissl., Trichodenna harzianum Rifai, and Epicoccum nigrum Link alone and in combination with the peach canker pathogen Leucostoma cincta (Fr.:Fr.) Höhn. Bark tissues were sampled over a time series for light and fluorescence microscopic examination to determine the influence of inoculations on the ontogeny of tissues associated with wound healing, specifically the extent of formation of the polysaccharide-impregnated zone, the ligno-suberized boundary layer, and the necrophylactic (wound) periderm. None of the inoculations with epiphytic fungi were associated with as quick a formation of wound-related tissues as observed in the noninoculated control wounds. Inoculation of wounds with T. harzianum resulted in delayed formation, but not prevention, of tissues critical to normal wound healing. Combined inoculations of L. cincta and epiphytes resulting in wound healing similar to that of inoculations with the epiphyte alone were observed consistently. Inoculation of wounds with E. nigrum alone, or in combination with L. cincta, did not cause any deleterious effects on the wound responses examined in this study. Key words: Alternaria, biological control, Epicoccum, Trichodenna, wounding.
The influence of petals on reproductive success in the arctic poppy (Papaver radicatum)
Authors: Corbett Andrea L. , Krannitz Pam G. , Aarssen Lonnie W.
Published: December 2007

The flowers of the arctic poppy (Papaver radicatum L.) track the sun, and the petals of the flowers reflect light towards the ovary. This study investigated the importance of petals to reproductive success in this species. We measured light intensity, ovary temperature, seed weight, and number of seeds produced by flowers that had their petals removed versus flowers with their petals intact. Flowers without petals do not track the sun. Irradiance was greater when the photocell was held coincident with the angle of sun-tracking flowers than when facing upward. Flowers with petals had significantly higher overy temperatures both at the ovary surface and in the ovary interior than did flowers lacking petals. In pairs of flowers on the same individual plant, those with their petals removed had significantly fewer and smaller seeds than control flowers with petals intact. There were site differences in the significance of the treatment effect, but not in the magnitude of the differences between flowers with and without petals. Therefore, the presence of petals resulted in increased irradiance and temperature at and in the ovary, which affected reproductive success. Key words: heliotropism, Papaver radicatum, petals, reproductive success, temperature.
Photoinhibition of photophosphorylation, adenosine triphosphate content, and glyceraldehyde-3-phosphate dehydrogenase (NADP+) following high-irradiance desiccation of Selaginella lepidophylla
Authors: Lebkuecher Jefferson G. , Eickmeier William G.
Published: December 2007

Selaginella lepidophylla (Hook, and Grev.) Spring, a poikilohydrous desert pteridophyte, curls dramatically during desiccation. As part of a larger study of potential photoinhibition in this resurrection plant, the hypothesis that stem curling may ameliorate high-irradiance reduction of light-activated enzyme activities, noncyclic photophosphorylation, and adenosine triphosphate content was tested under laboratory conditions. Plants restrained from curling during desiccation at a constant irradiance of 2000 μmol ∙ m−2 ∙ s−1 when rehydrated had significantly decreased glyceraldehyde-3-phosphate dehydrogenase (NADP+) enzyme activity, noncyclic photophosphorylation, and adenosine triphosphate content relative to plants that were allowed to curl naturally under the same conditions. Ribulose bisphosphate carboxylase and malate dehydrogenase enzyme activities were not significantly affected by the restraint treatment. These results demonstrate that stem curling during desiccation limits bright-light damage that could otherwise decrease photophosphorylation capacity, adenosine triphosphate content, and light-activated carbon assimilation enzyme activity when the plants are next wetted. In addition, examination of the adenosine phosphate contents of desiccated, 24-h dark hydrated, and 24-h 500 μmol ∙ m−2 ∙ s−1 irradiance hydrated Selaginella lepidophylla plants revealed that adenosine triphosphate pools were not conserved during desiccation and that during hydration in the light, adenosine triphosphate content increases substantially as a result of both oxidative and photophosphorylation. Key words: Selaginella lepidophylla, photoinhibition, desiccation tolerance, photophosphorylation, adenosine phosphate.
ANGULAR MOMENTUM CONSERVATION LAW FOR RANDALL–SUNDRUM MODELS
Authors: LIU YU-XIAO , DUAN YI-SHI , ZHANG LI-JIE
Published: December 2007

In Randall–Sundrum models, by the use of general Noether theorem, the covariant angular momentum conservation law is obtained with respect to the local Lorentz transformations. The angular momentum current also has superpotential and is therefore identically conserved. The space-like components Jijof the angular momentum for Randall–Sundrum models are zero. But the component J04is infinite.
QUASI-SPHERICAL STAR OF DARK MATTER AND DARK ENERGY AND A STUDY OF ITS COLLAPSE DYNAMICS
Authors: BANDYOPADHYAY TANWI , CHAKRABORTY SUBENOY
Published: December 2007

The collapse dynamics of an inhomogeneous quasi-spherical star is investigated in the background of dark matter (DM) and dark energy (DE). The dark matter is taken in the usual form of dust cloud and for dark energy, anisotropic fluid is chosen. The gravitational collapse is studied in two different situations: (a) a simple choice of the metric coefficient, (b) the radial pressure is assumed to be zero. The role of dark energy in the formation of apparent horizon is studied and it is examined how dark energy modifies the collapsing process.
MASS SPECTRUM OF QUANTUM BLACK HOLES FROM NEWTONIAN-GRAVITY AND QUANTUM-POTENTIAL APPROACH
Authors: LAN DANG MONG
Published: December 2007

In earlier papers, we have introduced an approach for quantum-gravitational bodies based on the quantum potential written in the form of an equation of state to be added to equations of gravitation theories. In the case of Einsteinian gravitation, we have obtained quantum black holes by rough calculation but, in the case of Newtonian gravitation, with additional assumption on "no-escape" radius for light, the same bodies may be obtained by simple but rigorous mathematical calculation. This paper deals with Newtonian rotating quantum black holes and derives their mass spectrum that is closed to those of some authors based on relativistic treatment.
DIRAC QUANTIZATION OF RESTRICTED QCD
Authors: CHO Y. M. , HONG SOON-TAE , KIM J. H. , PARK YOUNG-JAI
Published: December 2007

We discuss the quantization of the restricted gauge theory of SU(2) QCD regarding it as a second-class constraint system, and construct the BRST symmetry of the constrained system in the framework of the improved Dirac quantization scheme. Our analysis tells that one could efficiently quantize the restricted QCD under the BRST symmetry as if it is a first-class constraint system.
ZERO TEXTURE MODEL AND SO(10) GUT
Authors: FUKUYAMA TAKESHI , MATSUDA KOICHI , NISHIURA HIROYUKI
Published: December 2007

We study the bridge between the phenomenological mass matrix model and SO(10) GUT. Namely, we consider the four-zero texture model in the framework of the renormalizable SO(10) GUT model. This unification gives more stringent constraints than the case where only either model is considered. However, we can obtain good fitting by expanding the minimal SO(10) GUT to include 120 in addition to 10 and [Formula: see text] in Yukawa coupling and by considering both type I and type II seesaw mechanisms.
SPECTRUM IN THE BROKEN PHASE OF A λϕ4THEORY
Authors: FRASCA MARCO
Published: December 2007

We derive the spectrum in the broken phase of a λϕ4theory, in the limit λ→∞, showing that this goes as even integers of a renormalized mass in agreement with recent lattice computations.
CONSTRAINING MODELS OF MODIFIED GRAVITY WITH THE DOUBLE PULSAR PSR J0737-3039A/B SYSTEM
Authors: IORIO LORENZO , RUGGIERO MATTEO LUCA
Published: December 2007

In this paper we use ΔP = -1.772341 ± 13.153788 s between the phenomenologically determined orbital period P b of the PSR J0737-3039A/B double pulsar system and the purely Keplerian period [Formula: see text] calculated with the system's parameters, determined independently of the third Kepler law itself, in order to put constraints on some models of modified gravity (f(R), Yukawa-like fifth force, MOND). The major source of error affecting ΔP is not the one in the phenomenologically measured period (δP b = 4×10-6 s ), but the systematic uncertainty δP(0) in the computed Keplerian one due to the relative semimajor axis a mainly caused, in turn, by the errors in the ratio [Formula: see text] of the pulsars' masses and in sin i. We get |κ| ≤ 0.8 × 10-26 m -2 for the parameter that in the f(R) framework is a measure of the nonlinearity of the theory, |α| ≤ 5.5 × 10-4 for the fifth-force strength parameter (for λ ≈ a = 0.006 AU ). The effects predicted by the strong-acceleration regime of MOND are far too small to be constrained with some effectiveness today and in the future as well. In view of the continuous timing of such an important system, it might happen that in the near future it will be possible to obtain somewhat tighter constraints.
RUNNING MASS OF THE b-QUARK IN QCD AND SUSY QCD
Authors: BEDNYAKOV A. V.
Published: December 2007

The running mass of the b-quark defined in [Formula: see text]-scheme is one of the important parameters of SUSY QCD. To find its value, it should be related to some known experimental input. In this paper, the b-quark running mass defined in nonsupersymmetric QCD is chosen for determination of the corresponding parameter in SUSY QCD. The relation between these two quantities is found by considering five-flavor QCD as an effective theory obtained from its supersymmetric extension. A numerical analysis of the calculated two-loop relation and its impact on the MSSM spectrum is discussed. Since for nonsupersymmetric models [Formula: see text]-scheme is more natural than [Formula: see text], we also propose a new procedure that allows one to calculate relations between [Formula: see text]- and [Formula: see text]-parameters. Unphysical ε-scalars that give rise to the difference between the above-mentioned schemes are assumed to be heavy and decoupled in the same way as physical degrees of freedom. By means of this method it is possible to "catch two rabbits," i.e. decouple heavy particles and turn from [Formula: see text] to [Formula: see text], at the same time. An explicit two-loop example of [Formula: see text] transition is given in the context of QCD. The advantages and disadvantages of the method are briefly discussed.
A NOTE ON THE TOPOLOGICAL ORDER OF NONCOMMUTATIVE HALL FLUIDS
Authors: BARBÓN J. L. F. , GERBER D.
Published: December 2007

We evaluate the ground state degeneracy of noncommutative Chern–Simons models on the two-torus, a quantity that is interpreted as the "topological order" of associated phases of Hall fluids. We define the noncommutative theory via T-duality from an ordinary Chern–Simons model with non-Abelian 't Hooft magnetic fluxes. Motivated by this T-duality, we propose a discrete family of noncommutative, non-Abelian fluid models, arising as a natural generalization of the standard noncommutative Chern–Simons effective models. We compute the topological order for these universality classes, and comment on their possible microscopic interpretation.
ON THE ONE-LOOP CORRECTION OF φ4 THEORY IN HIGHER DIMENSIONS
Authors: UL HAQ ANSARI RIZWAN , SURESH P. K.
Published: December 2007

We consider in this paper φ4 theory in higher dimensions. Using functional diagrammatic approach, we compute the one-loop correction to effective potential of the scalar field in five dimensions. It is shown that φ4 theory can be regularized in five dimensions. Temperature dependent one-loop correction and critical temperature βc are computed and βc depends on the fundamental scale [Formula: see text] of the theory. A brief discussion of symmetry restoration is also presented. The nature of phase transitions is examined and is of second order.
TWO LIMIT CASES OF BORN–INFELD EQUATIONS
Authors: PENG YUE-JUN , RUIZ JÉRÉMY
Published: December 2007

We study two limit cases λ → ∞ and λ → 0 in Born–Infeld equations. Here the parameter λ > 0 is interpreted as the maximal electric field in the electromagnetic theory and the case λ = 0 corresponds to the string theory. Formal limits are governed by the classical Maxwell equations and pressureless magnetohydrodynamics system, respectively. For studying the limit λ → ∞, a new scaling is introduced. We give the relations between these limits and Brenier high and low field limits. Finally, using compensated compactness arguments, the limits are rigorously justified for global entropy solutions in L∞in one space dimension, based on derived uniform estimates and techniques for linear Lagrangian systems.
DELTA SHOCK WAVES AS A LIMIT OF SHOCK WAVES
Authors: MITROVIĆ DARKO , NEDELJKOV MARKO
Published: December 2007

We discus the existence of delta shock waves obtained as a limit of two shock waves. For that purpose we perturb a prototype of weakly hyperbolic 2 × 2 system (sometimes called the "generalized pressureless gas dynamics model") by an additional term (called the "generalized vanishing pressure"). The obtained perturbed system is strictly hyperbolic and its Riemann problem is solvable. Since it is genuinely nonlinear, its solution consists of shocks and rarefaction waves combination. As perturbation parameter vanishes, the solution converges in the space of distribution. Specially, a solution consisting of two shocks converge to a delta function. Also, we give a formal definition of approximate solution and prove a kind of entropy argument. The paper finishes by a discussion about delta shock interactions for the original system.
THE HIGH FIELD ASYMPTOTICS FOR A FERMIONIC BOLTZMANN EQUATION: ENTROPY SOLUTIONS AND KINETIC SHOCK PROFILES
Authors: BEN ABDALLAH NAOUFEL , CHAKER HEDIA , SCHMEISER CHRISTIAN
Published: December 2007

The high field approximation of a fermionic Boltzmann equation of semiconductors is performed after the formation of shocks. By employing a new entropy, whose dissipation measures the departure from the high field equilibrium, convergence towards the entropic solution of the limiting conservation law is proven. The entropy is also used to construct kinetic shock profiles for entropic shocks and to prove non-existence of non-entropic shock profiles.
ON THE CLASSICAL SOLUTIONS OF THE MOTION OF AN ELASTIC STRING IN AN n-DIMENSIONAL SPACE
Authors: MANFRIN RENATO
Published: December 2007

We study the C1 solutions of the motion of a perfectly elastic string in an n-dimensional space. We prove a result of formation of singularities and, in a particular case, we characterize the behavior of the global solutions.
VISCOSITY SOLUTIONS OF HAMILTON–JACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS
Authors: COCLITE GIUSEPPE MARIA , RISEBRO NILS HENRIK
Published: December 2007

We consider Hamilton–Jacobi equations, where the Hamiltonian depends discontinuously on both the spatial and temporal location. Our main result is the existence of viscosity solution to the Cauchy problem, and that the front tracking algorithm yields an L∞ contractive semigroup. We define a viscosity solution by treating the discontinuities in the coefficients analogously to "internal boundaries". The existence of viscosity solutions is established constructively via a front tracking approximation, whose limits are viscosity solutions, where by "viscosity solution" we mean a viscosity solution that posses some additional regularity at the discontinuities in the coefficients. We then show a comparison result that is valid for these viscosity solutions.
RATIONAL REPRESENTATIONS OF PRIMES BY BINARY QUADRATIC FORMS
Authors: EVANS RONALD , VAN VEEN MARK
Published: December 2007

Let q be a positive squarefree integer. A prime p is said to be q-admissible if the equation p = u2+ qv2has rational solutions u, v. Equivalently, p is q-admissible if there is a positive integer k such that [Formula: see text], where [Formula: see text] is the set of norms of algebraic integers in [Formula: see text]. Let k(q) denote the smallest positive integer k such that [Formula: see text] for all q-admissible primes p. It is shown that k(q) has subexponential but suprapolynomial growth in q, as q → ∞.
LINEAR CONGRUENCES AND RELATIONS ON SPACES OF CUSP FORMS
Authors: EL-GUINDY AHMAD
Published: December 2007

Let p be a prime and let f be any cusp form of level l ∈ {2,3,5,7,13} whose weight satisfy a certain congruence modulo (p-1). Then we exhibit explicit linear combinations of the coefficients of f that must be divisible by p. For a normalized Hecke eigenform, this translates (under mild restrictions) into the pth coefficient itself being divisible by a prime ideal above p in the ring generated by the coefficients of f. This provides many instances of the so-called non-ordinary primes. We also discuss linear relations satisfied universally on the space of modular forms of these levels. These results extend recent work of Choie, Kohnen and Ono in the level 1 case.
ON THE EISENSTEIN IDEAL OF DRINFELD MODULAR CURVES
Authors: PÁL AMBRUS
Published: December 2007

Let 𝔈(𝔭) denote the Eisenstein ideal in the Hecke algebra 𝕋(𝔭) of the Drinfeld modular curve X0(𝔭) parameterizing Drinfeld modules of rank two over 𝔽q[T] of general characteristic with Hecke level 𝔭-structure, where 𝔭 ◃ 𝔽q[T] is a non-zero prime ideal. We prove that the characteristic p of the field 𝔽qdoes not divide the order of the quotient 𝕋(𝔭)/𝔈(𝔭) and the Eisenstein ideal 𝔈(𝔭) is locally principal.
COURBES ELLIPTIQUES SEMI-STABLES SUR LES CORPS DE NOMBRES
Authors: KRAUS ALAIN
Published: December 2007

Let K be a number field. In this paper, we are interested in the following problem: does there exist a constant cK, which depends only on K, such that for any semi-stable elliptic curve defined over K, the Galois representation in its p-torsion points is irreducible whenever p is a prime number greater than cK? In case the answer is positive, how can we get such a constant? We prove that if a certain condition is satisfied by K, the answer is positive and we obtain cK explicitly. Furthermore, we prove that this condition is realized in many situations.
MHC, TSP, and the Origin of Species: From Immunogenetics to Evolutionary Genetics
Authors: Klein Jan , Sato Akie , Nikolaidis Nikolas
Published: December 2007

The acronym Mhc, major histocompatibility complex, is customarily not allied with topics in evolutionary biology. Here, however, we attempt to demonstrate that the Mhc has much to offer to this discipline and intimate that evolutionary biologists who ignore its contributions miss out on a chance of applying a new approach to vexing questions. One aspect of the Mhc in particular affords a fresh look at the population processes that transform one species into another: the trans-species polymorphism, the passage of allelic lineages from ancestral to descendant species. We provide examples of using the Mhc polymorphism in estimating the size of the founding population of new species, and of analyzing the long-term population demographies of phylogenetic lineages. We then extend the concept of trans-species polymorphism to other genes, even those not evolving under balancing selection, and argue that the phenomenon is widespread between closely related species. On the example of the cichlid fishes of Lake Victoria, we demonstrate how the concept changes the interpretation of this so-called “species flock.” We contend that the conclusions reached regarding the cichlid fishes apply also to other examples of adaptive radiation, for example that of Darwin's finches, and so provide new insights into the nature of speciation in general.
Cell Turnover and Adult Tissue Homeostasis: From Humans to Planarians
Authors: Pellettieri Jason , Alvarado Alejandro Sánchez
Published: December 2007

Many fully developed metazoan tissues remain in a state of flux throughout life. During physiological cell turnover, older differentiated cells are typically eliminated by apoptosis and replaced by the division progeny of adult stem cells. Independently, each of these processes has been researched extensively, yet we know very little about how cell death and stem cell division are coordinated in adult organs. Freshwater planarians are an attractive model organism for research in this area. Not only do they undergo a very high rate of somatic cell turnover throughout life, but experimental tools are now available to study this process in vivo. Together, these attributes provide an opportunity to investigate the mechanisms, functions, and regulation of cell turnover in adult tissues.
Oxidation of GaAs1 − x
P
x
Surface by Oxygen Plasma and Properties of Oxide Film
Authors: Sugano Takuo , Mori Yoshifumi
Published: December 2007

This paper presents a new technology for oxidizing a

GaAs

1
−
x

P

x

 
(
x
=
0
∼
1
)

surface by oxygen plasma, produced by high‐frequency discharge in oxygen, whose pressure is of the order of about 0.1 ∼ 1.0 Torr. Growth rate of the oxide film is remarkably high, and can be controlled by the oxygen gas pressure and the high‐frequency field over a range of 50 Aå/sec to 1 μ/sec. The plasma‐oxidized films have complex composition, including polycrystalline

β
‐

Ga

2

O

3

,

GaAsO

4

, and

GaPO

4

. The refractive index of these films measured by ellipsometry reveals a dependence on the substrate material and on film thickness, and also distribution in the film, so that the refractive index changes from a value, corresponding to

β
‐

Ga

2

O

3

at the top surface, to the value approximately equal to that of the substrate material at the oxide‐substrate interface. Such distribution of the refractive index is useful for attaining optical isolation in monolithic optical integrated circuits. Furthermore, this technique has various applications, such as the surface passivation of

GaAs

1
−
x

P

x

devices and dielectric isolation in

GaAs

integrated circuits, fabricated on a semiinsulating substrate.
Anodic Deposition of Ferric Oxy‐Hydroxide Films on Platinum from Perchlorate Solutions
Authors: Hashimoto Koji , Cohen Morris
Published: December 2007

The effect of pH and added anions such as phosphate, acetate, chloride, or sulfate in perchlorate solutions on the anodic deposition of ferric oxy‐hydroxide films on platinum was studied. In all cases deposition took place by the oxidation of a ferrous species to a ferric film with 100% current efficiency. The growth rate of the film was dependent on the concentration of

FeOH

+

ion which was the depositing species in a ferrous perchlorate solution and in the solutions containing acetate, chloride, or sulfate. In the solution contain‐ing phosphate, the anodic deposition proceeded by the simultaneous oxidation of

FeOH

+

and

FeH

2

PO

4

+

ions to

γ
‐
FeOOH

and

FePO

4

·
2

H

2

O

.
Two‐Dimensional Current Distribution Within a Packed‐Bed Electrochemical Flow Reactor
Authors: Alkire Richard , Ng Patrick K.
Published: December 2007

An analysis is presented for describing behavior of a packed‐bed electrode confined within a thin cylindrical porous separator and surrounded by a concentric counterelectrode. Electrolytic solution, containing reactive species, flows axially in plug flow through the packed‐bed electrode while the peripheral surface of the packed bed is held under a constant applied potential. Results are obtained for two types of porous separators, (i) permeable to all solute species and (ii) impermeable to the reactive solute species. For each case, the two‐dimensional (radial and axial) concentration, potential, and current distributions are calculated by a finite difference method. The results clarify over‐all reactor performance and, in particular, predict the relation between the volumetric reaction rate and the residence time for a wide range of system parameters.
Contributions of Oxygen, Silicon, and Hydrogen to the Interface States of an Si ‐ SiO2, Interface
Authors: Fahrner W.
Published: December 2007

Oxygen, silicon, and hydrogen ions are implanted with doses of

10

10

−

10

15

/

cm

2

through the oxide of a MOS structure. The development of induced levels in Si can be observed. Annealing experiments from room temperature to 800°C show the transition from the nonequilibrium incorporation to the initial (nonimplanted) state. Hydrogen implantation hinders the restoration of a

Si
‐

SiO

2

interface under H2 annealing.
The Retention of Fluorine by Silicon Surfaces: Interaction with Gold‐Refractory Transistor Metallizations
Authors: Day H. , Christou A. , Bressan D. J.
Published: December 2007

The interaction of gold‐tantalum transistor metallizations with silicon substrates has been studied as a function of fluorine ion contamination. An

NH

4

F

buffered etch solution tagged with 118‐min half life 18F was used to quantitatively establish the fluorine contamination as a function of water rinse time and evacuation time before metal deposition. Pinhole formation in the refractory layer due to fluorine ion contamination with a subsequent rapid interdiffusion of gold and silicon during a 300°C anneal was shown to be a probable failure mechanism for transistors.
Solid‐State Coulometric Titration: Critical Analysis and Application to Wüstite
Authors: Giddings Robert A. , Gordon Ronald S.
Published: December 2007

A critical analysis was performed on galvanic cell techniques which employ calcia‐stabilized zirconia electrolytes. The presence of low‐level electron or hole conduction in the ionic conducting range of the electrolyte was found to be responsible for oxygen permeation through the electrolyte which can either oxidize or reduce a single‐phase oxide and, hence, lead to drift in the open‐circuit emf with time. Taking oxygen permeation into account quantitatively, a series of isothermal titration experiments in wüstite was performed in which the cell emf was found to be linear with composition (i.e., oxygen‐iron molal ratio). These results are in excellent agreement with a recent composite analysis of all thermodynamic data in the

Fe
‐
O

system. Previous cell studies in which deviant behavior has been reported are probably due to improper galvanic cell techniques. No evidence was found to support the existence of more than one‐phase or second‐order transitions within the wüstite phase.
X‐Ray Imaging Technique for Observing Liquid Encapsulation Czochralski Crystal Growth
Authors: Pruett H. D. , Lien S. Y.
Published: December 2007

An imaging technique has been developed to facilitate growth of uniform diameter crystals by the liquid encapsulation Czochralski method. A point source of x‐rays is used to produce a shadow image of the growing crystal on a scintillation screen. A high‐sensitivity TV camera converts the shadow image into a real‐time display on a TV monitor. System components are described, and results obtained from growing GaP crystals are presented.
Auger Electron Spectroscopy Determination of the Oxygen/Silicon Ratio in Spin‐On Glass Films
Authors: Smith J. N. , Thomas S. , Ritchie K.
Published: December 2007

Instrumental parameters for the determination of the oxygen/silicon ratio in

SiO

2

films using Auger electron spectroscopy have been studied and optimized. In the case of a binary system such as this, the ratio of the Auger peak heights from the two components is a measure of their relative abundance and can yield meaningful results when compared with a standard. This method has been utilized to determine the oxygen/silicon ratio in spin‐on glass films densified at various temperatures. The oxygen/silicon ratios of nondoped spin‐on glass films show a general trend to increase and approach 2 as densification temperatures increase. The structural re‐arrangement of the silica network at ̃400°C is also reflected by the oxygen/silicon ratios. The oxygen/silicon ratio for other commonly used oxide films produced from steam, oxygen, and CVD was also determined. The techniques and results of this study are discussed.
Accretion of visceral fat and hepatic insulin resistance in pregnant rats
Authors: Einstein Francine H. , Fishman Sigal , Muzumdar Radhika H. , Yang Xiao Man , Atzmon Gil , Barzilai Nir
Published: December 2007

Insulin resistance (IR) is a hallmark of pregnancy. Because increased visceral fat (VF) is associated with IR in nonpregnant states, we reasoned that fat accretion might be important in the development of IR during pregnancy. To determine whether VF depots increase in pregnancy and whether VF contributes to IR, we studied three groups of 6-mo-old female Sprague-Dawley rats: 1) nonpregnant sham-operated rats (Nonpreg; n = 6), 2) pregnant sham-operated rats (Preg; n = 6), and 3) pregnant rats in which VF was surgically removed 1 mo before mating (PVF−; n = 6). VF doubled by day 19 of pregnancy (Nonpreg 5.1 ± 0.3, Preg 10.0 ± 1.0 g, P < 0.01), and PVF− had similar amounts of VF compared with Nonpreg (PVF− 4.6 ± 0.8 g). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp in late gestation in chronically catheterized unstressed rats. Glucose IR (mg·kg−1·min−1) was highest in Nonpreg (19.4 ± 2.0), lowest in Preg (11.1 ± 1.4), and intermediate in PVF− (14.7 ± 0.6; P < 0.001 between all groups). During the clamp, Nonpreg had greater hepatic insulin sensitivity than Preg [hepatic glucose production (HGP): Nonpreg 4.5 ± 1.3, Preg 9.3 ± 0.5 mg·kg−1·min−1; P < 0.001]. With decreased VF, hepatic insulin sensitivity was similar to nonpregnant levels in PVF− (HGP 4.9 ± 0.8 mg·kg−1·min−1). Both pregnant groups had lower peripheral glucose uptake compared with Nonpreg. In parallel with hepatic insulin sensitivity, hepatic triglyceride content was increased in pregnancy (Nonpreg 1.9 ± 0.4 vs. Preg 3.2 ± 0.3 mg/g) and decreased with removal of VF (PVF− 1.3 ± 0.4 mg/g; P < 0.05). Accretion of visceral fat is an important component in the development of hepatic IR in pregnancy, and accumulation of hepatic triglycerides is a mechanism by which visceral fat may modulate insulin action in pregnancy.
Testosterone exacerbates obstructive renal injury by stimulating TNF-α production and increasing proapoptotic and profibrotic signaling
Authors: Metcalfe Peter D. , Leslie Jeffrey A. , Campbell Matthew T. , Meldrum Daniel R. , Hile Karen L. , Meldrum Kirstan K.
Published: December 2007

Upper urinary tract obstruction is a common cause of renal dysfunction in children and adults. While there is clinical evidence of an increased male incidence and mortality rate with acute renal failure, the effect of gender and testosterone on obstructive renal injury has not previously been evaluated. We hypothesized that testosterone exacerbates proinflammatory TNF-α production and proapoptotic and profibrotic signaling during renal obstruction, resulting in increased apoptotic cell death and tubulointerstitial fibrosis. To study this, male, female, castrated male, and testosterone-treated oophorectomized female rats were subjected to sham operation or 3 days of unilateral ureteral obstruction (UUO). Renal cortical tissue was then analyzed for TNF-α production; proapoptotic caspase-8, -9, and -3 activity; apoptotic cell death; profibrotic transforming growth factor-β1 production; and α-smooth muscle actin expression. In a separate arm, glomerular filtration rate (inulin clearance) was measured in rats pre- and post-UUO. Male and testosterone-treated oophorectomized female rats demonstrated a significant increase in TNF-α production, caspase activity, apoptotic cell death, tubulointerstitial fibrosis, and renal dysfunction during UUO compared with castrated males and normal female rats subjected to the same time course of obstruction. These results demonstrate that endogenous testosterone production in normal male rats and testosterone exogenously administered to oophorectomized females significantly increases TNF production and proapoptotic and profibrotic signaling during renal obstruction, resulting in increased apoptotic cell death, tubulointerstitial fibrosis, and renal dysfunction.
Chorionic enhancer is dispensable for regulated expression of the human renin gene
Authors: Zhou Xiyou , Sigmund Curt D.
Published: December 2007

We tested the hypothesis that a transcriptional chorionic enhancer (CE), previously identified to increase human renin expression in choriodecidual cells is required to mediate tissue-specific, cell-specific, and regulated expression of human renin in transgenic mice. Recombineering was used to delete the CE upstream of the renin gene alone or in combination with the kidney enhancer (KE) in a large artificial chromosome construct containing the entire human renin gene and extensive flanking sequences. Deletion of the CE had no qualitative or quantitative effect on the tissue-specific expression of human renin, nor on the cellular localization of human renin in the kidney or placenta. Combined deletion of both the CE and KE caused a decrease in the level of renal renin expression consistent with the established role of the KE. We also considered the possibility that the CE is a downstream enhancer of the KiSS1 gene, which lies directly upstream of renin and is also expressed in the placenta. Deletion of the CE alone, or the CE and KE together, had no effect on the level of KiSS1 expression in the placenta. These data provide convincing evidence that the CE is silent in vivo, at least in the mouse. The absence of a phenotype caused by deletion of the CE is consistent with the observation that the sequence is not evolutionarily conserved.
Melatonin ameliorates oxidative stress, inflammation, proteinuria, and progression of renal damage in rats with renal mass reduction
Authors: Quiroz Yasmir , Ferrebuz Atilio , Romero Freddy , Vaziri Nosratola D. , Rodriguez-Iturbe Bernardo
Published: December 2007

The progressive deterioration of renal function and structure resulting from renal mass reduction are mediated by a variety of mechanisms, including oxidative stress and inflammation. Melatonin, the major product of the pineal gland, has potent_antioxidant and anti-inflammatory properties, and its production is impaired in chronic renal failure. We therefore investigated if melatonin treatment would modify the course of chronic renal failure in the remnant kidney model. We studied rats followed 12 wk after renal ablation untreated (Nx group, n = 7) and treated with melatonin administered in the drinking water (10 mg/100 ml) (Nx + MEL group, n = 8). Sham-operated rats ( n = 10) were used as controls. Melatonin administration increased 13–15 times the endogenous hormone levels. Rats in the Nx + MEL group had reduced oxidative stress (malondialdehyde levels in plasma and in the remnant kidney as well as nitrotyrosine renal abundance) and renal inflammation (p65 nuclear factor-κB-positive renal interstitial cells and infiltration of lymphocytes and macrophages). Collagen, α-smooth muscle actin, and transforming growth factor-β renal abundance were all increased in the remnant kidney of the untreated rats and were reduced significantly by melatonin treatment. Deterioration of renal function (plasma creatinine and proteinuria) and structure (glomerulosclerosis and tubulointerstitial damage) resulting from renal ablation were ameliorated significantly with melatonin treatment. In conclusion, melatonin administration improves the course of chronic renal failure in rats with renal mass reduction. Further studies are necessary to define the potential usefulness of this treatment in other animal models and in patients with chronic renal disease.
Intracrystalline urinary proteins facilitate degradation and dissolution of calcium oxalate crystals in cultured renal cells
Authors: Grover Phulwinder K. , Thurgood Lauren A. , Fleming David E. , van Bronswijk Wilhelm , Wang Tingting , Ryall Rosemary L.
Published: December 2007

We have previously proposed that intracrystalline proteins would increase intracellular proteolytic disruption and dissolution of calcium oxalate (CaOx) crystals. Chauvet MC, Ryall RL. J Struct Biol 151: 12–17, 2005; Fleming DE, van Riessen A, Chauvet MC, Grover PK, Hunter B, van Bronswijk W, Ryall RL. J Bone Miner Res 18: 1282–1291, 2003; Ryall RL, Fleming DE, Doyle IR, Evans NA, Dean CJ, Marshall VR. J Struct Biol 134: 5–14, 2001. The aim of this investigation was to determine the effect of increasing concentrations of intracrystalline protein on the rate of CaOx crystal dissolution in Madin-Darby canine kidney (MDCKII) cells. Crystal matrix extract (CME) was isolated from urinary CaOx monohydrate (COM) crystals. Cold and [14C]oxalate-labeled COM crystals were precipitated from ultrafiltered urine containing 0–5 mg/l CME. Crystal surface area was estimated from scanning electron micrographs, and synchrotron X-ray diffraction was used to determine nonuniform strain and crystallite size. Radiolabeled crystals were added to MDCKII cells and crystal dissolution, expressed as radioactive label released into the medium, was measured. Increasing CME content did not significantly alter crystal surface area. However, nonuniform strain increased and crystallite size decreased in a dose-response manner, both reaching saturation at a CME concentration of 3 mg/ and demonstrating unequivocally the inclusion of increasing quantities of proteins in the crystals. This was confirmed by Western blotting. Crystal dissolution also followed saturation kinetics, increasing proportionally with final CME concentration and reaching a plateau at a concentration of ∼2 mg/l. These findings were complemented by field emission scanning electron microscopy, which showed that crystal degradation also increased relative to CME concentration. Intracrystalline proteins enhance degradation and dissolution of CaOx crystals and thus may constitute a natural defense against urolithiasis. The findings have significant ramifications in biomineral metabolism and pathogenesis of renal stones.
Testing Basal Ganglia Motor Functions Through Reversible Inactivations in the Posterior Internal Globus Pallidus
Authors: Desmurget M. , Turner R. S.
Published: December 2007

To test current hypotheses on the contribution of the basal ganglia (BG) to motor control, we examined the effects of muscimol-induced inactivations in the skeletomotor region of the internal globus pallidus (sGPi) on visually directed reaching. Injections were made in two monkeys trained to perform four out-and-back reaching movements in quick succession toward four randomly selected target locations. Following sGPi inactivations the following occurred. 1) Peak velocity and acceleration were decreased in nearly all sessions, whereas movement duration lengthened inconsistently. 2) Reaction times were unaffected on average, although minor changes were observed in several individual sessions. 3) Outward reaches showed a substantial hypometria that correlated closely with bradykinesia, but directional accuracy was unaffected. 4) Endpoint accuracy was preserved for the slow visually guided return movements. 5) No impairments were found in the rapid chaining of out-and-back movements, in the selection or initiation of four independent reaches in quick succession or in the quick on-line correction of initially misdirected reaches. 6) Inactivation-induced reductions in the magnitude of movement-related muscle activity (EMG) correlated with the severity of slowing and hypometria. There was no evidence for inactivation-induced alterations in the relative timing of EMG bursts, excessive cocontraction, or impaired suppression of antagonist EMG. Therefore disconnecting the BG motor pathway consistently produced bradykinesia and hypometria, but seldom affected movement initiation time, feedback-mediated guidance, the capacity to produce iterative reaches, or the ability to abruptly reverse movement direction. These results are discussed with reference to the idea that the BG motor loop may regulate energetic expenditures during movement (i.e., movement “vigor”).
The Role of Shear Stress on ET-1, KLF2, and NOS-3 Expression in the Developing Cardiovascular System of Chicken Embryos in a Venous Ligation Model
Authors: Groenendijk Bianca C. W. , Van der Heiden Kim , Hierck Beerend P. , Poelmann Robert E.
Published: December 2007

In this review, the role of wall shear stress in the chicken embryonic heart is analyzed to determine its effect on cardiac development through regulating gene expression. Therefore, background information is provided for fluid dynamics, normal chicken and human heart development, cardiac malformations, cardiac and vitelline blood flow, and a chicken model to induce cardiovascular anomalies. A set of endothelial shear stress-responsive genes coding for endothelin-1 (ET-1), lung Krüppel-like factor (LKLF/KLF2), and endothelial nitric oxide synthase (eNOS/NOS-3) are active in development and are specifically addressed.
Tandem Mass Spectrometry in Physiology
Authors: Pisitkun Trairak , Hoffert Jason D. , Yu Ming-Jiun , Knepper Mark A.
Published: December 2007

Tandem mass spectrometry coupled to liquid chromatography (LC-MS/MS) allows identification of proteins in a complex mixture without need for protein purification (“shotgun” proteomics). Recent progress in LC-MS/MS-based quantification, phosphoproteomic analysis, and targeted LC-MS/MS using multiple reaction monitoring (MRM) has made LC-MS/MS a powerful tool for the study of cell physiology.
Suppression of 11β-hydroxysteroid dehydrogenase type 1 with RNA interference substantially attenuates 3T3-L1 adipogenesis
Authors: Liu Yong , Park Frank , Pietrusz Jennifer L. , Jia Guangfu , Singh Ravinder J. , Netzel Brian C. , Liang Mingyu
Published: December 2007

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1), which regulates the local level of glucocorticoids, has been suggested to be involved in the development of obesity. A definitive functional role for 11β-HSD1 in adipogenesis, however, remains to be established. We developed 3T3-L1 cell lines stably transfected with a small hairpin RNA (shRNA) targeting 11β-HSD1. A shRNA containing two nucleotide substitutions was used as a control. Silencing of 11β-HSD1 substantially attenuated the accumulation of lipid droplets and the expression of adipogenesis marker genes, which was induced by a mixture containing either corticosterone or dexamethasone. Silencing of 11β-HSD1 increased the concentration of 11-dehydrocorticosterone in the culture supernatant but did not significantly affect the levels of corticosterone or dexamethasone. Translocation of glucocorticoid receptors to the nucleus in response to glucocorticoids was significantly attenuated by silencing 11β-HSD1. The number of cells entering the S phase of the cell cycle following the induction of adipogenesis was significantly reduced by silencing 11β-HSD1. 11β-HSD1 shRNA delivered by lentiviral vectors after the induction of differentiation, however, did not affect the progression of adipogenesis. These results indicate that 11β-HSD1 plays a significant functional role in the initiation of 3T3-L1 adipogenesis and provide new mechanistic insights into the role of 11β-HSD1 in the development of obesity and related diseases.
Aging alters gene expression of growth and remodeling factors in human skeletal muscle both at rest and in response to acute resistance exercise
Authors: Dennis Richard A. , Przybyla Beata , Gurley Cathy , Kortebein Patrick M. , Simpson Pippa , Sullivan Dennis H. , Peterson Charlotte A.
Published: December 2007

The purpose of this investigation was to compare expression of genes that function in inflammation and stress, cell structure and signaling, or remodeling and growth in skeletal muscle of young (32 ± 7 yr, n = 15) and elderly (72 ± 5 yr, n = 16) healthy subjects before and after a bout of resistance leg exercises. A real-time RT-PCR method was used to screen 100 transcripts in v. lateralis biopsies obtained before and 72 h postexercise. The screen identified 15 candidates for differential expression due to aging and/or exercise that were measured quantitatively. The median levels of four mRNAs (insulin-like growth factor-1 and its binding protein IGFBP5, ciliary neurotrophic factor, and the metallopeptidase MMP2) were significantly affected by aging and were greater (1.6- to 2.3-fold, P ≤ 0.05) in the young than elderly muscle at both time points. The median levels of three mRNAs were significantly ( P ≤ 0.05) affected by exercise in the young. The metallopeptidase inhibitor TIMP1 and α-cardiac actin mRNAs increased 2-fold and 6.5-fold, respectively, and GDF8 (myostatin) mRNA decreased by 50%. However, elderly muscle did not display any significant changes in gene expression postexercise. Thus, aging muscle shows decreased levels at rest and an impaired response to exercise for a number of mRNAs for factors potentially involved in muscle growth and remodeling. Future studies must determine the functional importance of these gene expression changes to protein synthesis, satellite cell activity, and other processes that are directly involved in the mechanisms of muscle hypertrophy.