bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of acylated flavonoid‐O‐glycosides and methoxylated flavonoids from Tagetes maxima by liquid chromatography coupled to electrospray ionization tandem mass spectrometry
Authors: Parejo Irene , Jáuregui Olga , Viladomat Francesc , Bastida Jaume , Codina Carles
Published: November 2004

Liquid chromatography coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) employing a triple quadrupole mass spectrometer was used in the structural determination of acylated flavonoid‐O‐glycosides and methoxylated flavonoids occurring in Tagetes maxima. The compounds were identified by experiments in full scan mode (MS), and tandem mass experiments (MS/MS) of precursor ion scan, product ion scan, and neutral loss scan modes. In order to characterize the aglycones of the flavonoid glycosides, in‐source fragmentation of the deprotonated molecule [MH]− followed by product ion scan of the resulting aglycone [AH]− were performed. This combined approach allowed the identification of 51 phenolic compounds, including flavonoid‐O‐glycosides acylated with galloyl, protocatechuoyl, coumaroyl or caffeoyl groups, methoxylated flavonoids, and hydroxycinnamic acid and phenolic acid derivatives, none of them previously reported in Tagetes maxima. Copyright © 2004 John Wiley & Sons, Ltd.
Transfer theorems and asymptotic distributional results for m‐ary search trees
Authors: Fill James Allen , Kapur Nevin
Published: November 2004

We derive asymptotics of moments and identify limiting distributions, under the random permutation model on m‐ary search trees, for functionals that satisfy recurrence relations of a simple additive form. Many important functionals including the space requirement, internal path length, and the so‐called shape functional fall under this framework. The approach is based on establishing transfer theorems that link the order of growth of the input into a particular (deterministic) recurrence to the order of growth of the output. The transfer theorems are used in conjunction with the method of moments to establish limit laws. It is shown that: (i) for small toll sequences (tn) [roughly, tn = O(n1/2)] we have asymptotic normality if m ≤ 26 and typically periodic behavior if m ≥ 27; (ii) for moderate toll sequences [roughly, tn = ω(n1/2) but tn = o(n)] we have convergence to nonnormal distributions if m ≤ m0 (where m0 ≥ 26) and typically periodic behavior if m ≥ m0 + 1; and (iii) for large toll sequences [roughly, tn = ω(n)] we have convergence to nonnormal distributions for all values of m. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
The phase transition in the uniformly grown random graph has infinite order
Authors: Bollobás Béla , Janson Svante , Riordan Oliver
Published: November 2004

The aim of this paper is to study the emergence of the giant component in the uniformly grown random graph Gn(c), 0 < c < 1, the graph on the set[n] = {1, 2, …, n} in which each possible edge ij is present with probability c/ max{i, j}, independently of all other edges. Equivalently, we may start with the random graph Gn(1) with vertex set[n], where each vertex j is joined to each “earlier” vertex i < j with probability 1/j, independently of all other choices. The graph Gn(c) is formed by the open bonds in the bond percolation on Gn(1) in which a bond is open with probability c. The model Gn(c) is the finite version of a model proposed by Dubins in 1984, and is also closely related to a random graph process defined by Callaway, Hopcroft, Kleinberg, Newman, and Strogatz Phys Rev E 64 (2001), 041902. Results of Kalikow and Weiss Israel J Math 62 (1988), 257–268 and Shepp Israel J Math 67 (1989), 23–33 imply that the percolation threshold is at c = 1/4. The main result of this paper is that for c = 1/4 + ϵ, ϵ > 0, the giant component in Gn(c) has order exp(−Θ(1/√ϵ)) n. In particular, the phase transition in the bond percolation on Gn(1) has infinite order. Using nonrigorous methods, Dorogovtsev, Mendes, and Samukhin Phys Rev E 64 (2001), 066110 showed that an even more precise result is likely to hold. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Tailor‐Made Nanoparticles via Gas‐Phase Synthesis
Authors: Gutsch Andreas , Mühlenweg Heike , Krämer Michael
Published: November 2004

Gas‐phase synthesis is a well‐known chemical manufacturing technique for an extensive variety of nanoscale particles. Since the potential of ultrafine and, in particular, nanoscale particles in high‐performance applications has been identified, scientific and commercial interest has increased immensely, thus identifying this field as a most important technology of the future. However, nanomaterials can perform their multifunctional tasks only if they are customized in terms of chemical composition, size, and morphology to suit the application at hand. Profound knowledge of the synthesis and precise process control is crucial in meeting the stringent specifications. Although the gas‐phase synthesis of ultrafine materials has been known and commercially exploited for decades, existing knowledge is based almost exclusively on empirical know‐how. Process simulation is a very suitable tool for expanding the understanding of the synthesis‐relevant processes, particle formation mechanisms, and operating parameters. Based on the resulting expertise some special nanoscale gas‐phase products of high innovative potential have been developed.
On the Development of Colloidal Nanoparticles towards Multifunctional Structures and their Possible Use for Biological Applications
Authors: Pellegrino Teresa , Kudera Stefan , Liedl Tim , Muñoz Javier Almudena , Manna Liberato , Parak Wolfgang J.
Published: November 2004

In this Review, we describe the synthesis of high‐quality colloidal nanoparticles in organic solvents, the mechanisms by which they can be transferred into aqueous solution, and some of their applications in biology. In particular, we will place emphasis on the creation of multifunctional nanoparticles or nanoparticle assemblies.
Cover Picture: Top‐Down Meets Bottom‐Up: Dip‐Pen Nanolithography and DNA‐Directed Assembly of Nanoscale Electrical Circuits (Small 1/2005)
Authors: Chung Sung‐Wook , Ginger David S. , Morales Mark W. , Zhang Zhengfan , Chandrasekhar Venkat , Ratner Mark A. , Mirkin Chad A.
Published: November 2004

The cover picture shows a schematic representation of a nanoscale tunnel junction circuit formed when a DNA‐functionalized gold nanoparticle is directed between two metallic electrodes (a field‐emission SEM image is shown in the inset). The background displays an electron microscopy image of a device containing such junctions for potential use as a biosensor. Such a combination of biology, chemistry, engineering, and materials science serves as a model for the interdisciplinary character that Small exemplifies. For more information, please refer to the Communication by C. A. Mirkin and co‐workers on page 64 ff. The authors thank Yeechi Chen for the cover design.
From Exclusive Xia to Inclusive Zhu-Xia: The Conceptualisation of Chinese Identity in Early China
Authors: Zhi Chen
Published: November 2004

This paper involves an syncretic study of the structural characteristics, semantic stratification, graphical evolution and contextual analysis on a chronological base of the perplexing graphs and words which designate the Chinese, such as xia, hua and zhongguo, non-Chinese, such as yi, di, rong, and man, in early palaeographic and documentary sources. It shows how these terms evolved to distinguish between the two distinct ethnographical concepts in the early mind.

The study shows that the conception of Hua-Xia and Zhongguo carried different connotations in the Western Zhou period from that defined in Spring and Autumn philological sources. The relocation of the Zhou capital to the east during the transition from Western to Eastern Zhou had generically diffused the concept of Xia and the elegant Ya culture. The conception of Xia and Yi, which had formerly distinguished between the Zhou elites and the non-Zhou people, came to distinguish between the central states and peripheral groups in the geographical sense, as well as between the Zhou subjects and the non-Zhou subjects in the political sense. Thus the conceptualisation of the so-called “Chinese-ness” postdates the actual formation of the ethnographical bulk of the Chinese people.
A Stochastic Limit Approach to the SAT Problem
Authors: Accardi Luigi , Ohya Masanori
Published: November 2004

There exists an important problem whether there exists an algorithm to solve an NP-complete problem in polynomial time. In this paper, a new concept of quantum adaptive stochastic systems is proposed, and it is shown that it can be used to solve the problem above.
Low‐altitude distribution of radiation belt electrons
Authors: Selesnick R. S. , Looper M. D. , Albert J. M.
Published: November 2004

A numerical simulation of the low‐altitude electron radiation belt is described. It includes dependences on the electrons' bounce and drift phases, equatorial pitch angle, and kinetic energy in the range of ∼1 to several MeV at L = 3.5. Physical processes in addition to the adiabatic electron motion are pitch angle diffusion and backscattering from a realistic model atmosphere. Quasi‐linear diffusion coefficients are calculated from a model of the whistler mode plasmaspheric hiss wave intensity. Comparisons of the simulation results with electron data from a low‐altitude satellite show that the model accounts for the main features of the electron spatial distribution during selected periods of differing geomagnetic activity.
Carbon isotope evidence for changes in Antarctic Intermediate Water circulation and ocean ventilation in the southwest Pacific during the last deglaciation
Authors: Bostock Helen C. , Opdyke Bradley N. , Gagan Michael K. , Fifield L. Keith
Published: November 2004

Deep‐sea sediment core FR1/97 GC‐12 is located 990 mbsl in the northern Tasman Sea, southwest Pacific, where Antarctic Intermediate Water (AAIW) presently impinges the continental slope of the southern Great Barrier Reef. Analysis of carbon (δ13C) and oxygen (δ18O) isotope ratios on a suite of planktonic and benthic foraminifera reveals rapid changes in surface and intermediate water circulation over the last 30 kyr. During the Last Glacial Maximum, there was a large δ13C offset (1.1‰) between the surface‐dwelling planktonic foraminifera and benthic species living within the AAIW. In contrast, during the last deglaciation (Termination 1), the δ13Cplanktonic‐benthic offset reduced to 0.4‰ prior to an intermediate offset (0.7‰) during the Holocene. We suggest that variations in the dominance and direction of AAIW circulation in the Tasman Sea, and increased oceanic ventilation, can account for the rapid change in the water column δ13Cplanktonic‐benthic offset during the glacial‐interglacial transition. Our results support the hypothesis that intermediate water plays an important role in propagating climatic changes from the polar regions to the tropics. In this case, climatic variations in the Southern Hemisphere may have led to the rapid ventilation of deep water and AAIW during Termination 1, which contributed to the postglacial rise in atmospheric CO2.
Larvae of the genus Antiporus (Coleoptera : Dytiscidae) and phylogenetic implications
Authors: Alarie Yves , Watts Chris H. S.
Published: November 2004

The larvae of Antiporus blakeii (Clark), A. femoralis (Boheman), A. gilbertii (Clark), A. hollingsworthi Watts, A. jenniferae Watts, A. uncifer Sharp and A. willyamsi Watts are described with an emphasis on chaetotaxy of the head capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony analysis based on 17 informative larval characteristics was conducted using the program PAUP*. The 11 most parsimonious trees support a monophyletic origin of the genera Antiporus Sharp, Nebrioporus Régimbart, Scarodytes Gozis, and Stictotarsus Zimmermann. Unambiguous synapomorphies supporting this clade are the presence of natatory setae on the femur, tibia and tarsus and the presence of a very elongate urogomphomere 1. It is postulated that these features evolved as swimming devices. The genus Oreodytes Seidlitz is postulated to represent the sister-taxon of Antiporus + Nebrioporus + Stictotarsus + Scarodytes and this clade is characterised by the absence of the maxillary cardo and insertion of the primary seta MX1 on the maxillary stipes.
Drifting objects as habitat for pelagic juvenile fish off New South Wales, Australia
Authors: Dempster Tim , Kingsford Michael J.
Published: November 2004

The importance of drifting objects to small juvenile pelagic fish was investigated off the coast of New South Wales, Australia. Distance-related and temporal patterns in the distribution of clumps of drifting algae were investigated with 5000 m2 transects at five distances from shore (0.1, 0.5, 1, 5 and 10 km), two to three times per season for 2 years. Juvenile fish associated with drift algae were collected. Clumps of algae, predominantly Sargassum spp., were most abundant in spring, which coincided with the highest abundance of alga-associated post-flexion juvenile fish. Drift algae were also most abundant close to shore, probably due to the proximity to source and the dominant onshore winds. Fish were quickly attracted to drifting artificial objects (fish aggregation device; FADs), although the magnitude of attraction varied greatly among days. The relative abundance of small fish in open waters available to colonise FADs and differing weather conditions may explain much of this variability. More fish colonised FADs with an odour source than unscented control FADs, indicating small fish may use chemical cues to locate drifting structures. We conclude that juvenile fish actively seek drifting objects as pre-settlement habitat, which may reduce predation and enhance settlement opportunities.
Crystal structure of a human CD3-ε/δ dimer in complex with a UCHT1 single-chain antibody fragment
Authors: Arnett Kelly L. , Harrison Stephen C. , Wiley Don C.
Published: November 2004

The α/β T cell receptor complex transmits signals from MHC/peptide antigens through a set of constitutively associated signaling molecules, including CD3-ε/γ and CD3-ε/δ. We report the crystal structure at 1.9-Å resolution of a complex between a human CD3-ε/δ ectodomain heterodimer and a single-chain fragment of the UCHT1 antibody. CD3-ε/δ and CD3-ε/γ share a conserved interface between the Ig-fold ectodomains, with parallel packing of the two G strands. CD3-δ has a more electronegative surface and a more compact Ig fold than CD3-γ; thus, the two CD3 heterodimers have distinctly different molecular surfaces. The UCHT1 antibody binds near an acidic region of CD3-ε opposite the dimer interface, occluding this region from direct interaction with the TCR. This immunodominant epitope may be a uniquely accessible surface in the TCR/CD3 complex, because there is overlap between the binding site of the UCHT1 and OKT3 antibodies. Determination of the CD3-ε/δ structure completes the set of TCR/CD3 globular ectodomains and contributes information about exposed CD3 surfaces.
Adeno-associated viral vector delivers cardiac-specific and hypoxia-inducible VEGF expression in ischemic mouse hearts
Authors: Su Hua , Joho Shuji , Huang Yu , Barcena Alicia , Arakawa-Hoyt Janice , Grossman William , Kan Yuet Wai
Published: November 2004

It has been shown that the adeno-associated virus (AAV) vector can deliver the VEGF gene efficiently into the ischemic mouse myocardium. However, the AAV genomes can be found in extracardiac organs after intramyocardial injection. To limit unwanted VEGF expression in organs other than the heart, we tested the use of the cardiac myosin light chain 2v (MLC-2v) promoter and the hypoxia-response element to mediate cardiac-specific and hypoxia-inducible VEGF expression. An AAV vector, MLCVEGF, with 250 bp of the MLC-2v promoter and nine copies of the hypoxia-response element driving VEGF expression, was constructed. Gene expression was studied
in vitro
by infection of rat cardiomyocytes, rat skeletal myocytes, and mouse fibroblasts with the vector and
in vivo
by direct injection of the vector into normal and ischemic mouse hearts. With MLCVEGF infection, VEGF expression was higher in cardiomyocytes than the other two cell lines and was hypoxiainducible. VEGF expression was also higher in ischemic hearts than in normal hearts. No VEGF expression was detectable in organs with detectable MLCVEGF vectors other than the heart. MLCVEGF-injected ischemic hearts had more capillaries and small vessels around the injection site, smaller infarct size, and better cardiac function than the negative controls. Hence, MLCVEGF can mediate cardiac-specific and hypoxia-inducible VEGF expression, neoangiogenesis, infarct-size reduction, and cardiac functional improvement.
Gα13 Mediates a Signal That Is Essential for Proliferation and Survival of Thymocyte Progenitors
Authors: McNeil Coffield V. , Helms Whitney S. , Jiang Qi , Su Lishan
Published: November 2004

G protein signaling via the Gα12 family (Gα12 and Gα13) has not been well studied in T cells. To investigate whether Gα12 and Gα13 are involved in thymopoiesis, we expressed the regulator of G protein signaling domain of p115RhoGEF to inhibit Gα12 and Gα13 during thymopoiesis. Fetal thymus organ cultures seeded with p115ΔDH-expressing progenitor cells showed impaired thymopoiesis with a block at the CD4−CD8−CD44−CD25+ (DN3) stage. Using Gα13 or Gα12 minigenes, we demonstrated that Gα13, but not Gα12, is required for thymopoiesis. T progenitor cells expressing p115ΔDH showed reduced proliferation and increased cell death. T cell receptor stimulation of the fetal thymus organ cultures did not rescue the block. Overexpression of the antiapoptotic gene Bcl2 rescued the defect in DN3 cells and partially rescued T cell development. Therefore, Gα13-mediated signaling is necessary in early thymocyte proliferation and survival.
Mechanical Response of a Metallic Aortic Stent—Part II: A Beam-on-Elastic Foundation Model
Authors: Wang R. , Ravi-Chandar K.
Published: November 2004

The main objective of the paper is to develop the mathematical analysis of the response of a metallic stent subject to axisymmetric loads over its length and to different boundary conditions. These situations introduce bending stresses in the stent and cannot be captured by a model of the stent that can be used to characterize the pressure-diameter relationship under axially uniform loading. The analysis presented here is based on an analogy between a thin-walled pressure vessel and a beam on elastic foundation; in the present application, we derive an equivalent beam model for the bending response of a stent. Using this model, we evaluate the shape of the stent exiting the catheter as well as the variation of the diameter along the length of the stent constrained by stiff end supports. This approach can be used to evaluate the coupled response of the stent and the blood vessel, if the mechanical properties of the blood vessel are known. The coupled problem and its implications in the design of stents are discussed.
Equivalent Time Temperature Model for Physical Aging and Temperature Effects on Polymer Creep and Relaxation
Authors: Barbero Ever J. , Ford Kevin J.
Published: November 2004

The equivalent time temperature method (ETT) is a novel extension of the equivalent time method. ETT is developed in this work to deal with time-temperature shifting of long-term polymer and polymer composite creep data, including the effects of physical aging at nonuniform temperature. Modifications to classical testing methods and protocols are presented to obtain accurate and repeatable data that can support long-term predictions with nonuniform temperature conditions through time. These techniques are used to generate momentary Time temperature superposition (TTSP) master curves, temperature shift factor rates, and aging shift factor rates. Novel interpretation and techniques are presented to deal with the coupled age-temperature behavior over long times. Validation of predictions against over 20,000 Hr of long-term data in field conditions is presented.
Acoustic pulse propagation in an outdoor turbulent atmosphere
Authors: Mcleod I. D. , Don C. G. , Swenson G. G.
Published: November 2004

In a series of short-range experiments, attempts were made to relate the prevailing meteorological conditions to significant wave shape changes in a 2 ms acoustic pulse propagating over distances from 0.5 to 16 m. Unlike the findings in long-range studies involving time and spatial averages, no meaningful correlations between wind speed and acoustic pulse shape parameters were obtained. Pulse delays could be predicted provided detailed measurements of the wind speed were obtained. Observations showed that two adjacent paths could experience quite different propagation regimes. The geometry and pulse nature of the experiments described here restrict the scale of turbules in any cascade suggesting that a single turbule model may be applicable. Indeed using one or two effective turbules was capable of explaining many of the observations. One model approach used typical parameter values obtained from the literature or from measurements and by locating a single turbule at an appropriate distance from the source receiver axis, correctly generated the observed variety of wave forms. Alternatively, relying on measured data from one distorted pulse and the spatial wind profile, the model was used to determine subsequent pulse distortions. This was successful in predicting behavior in 76% of cases.
Estimation of the level and phase of the simple distortion tone in the modulation domain
Authors: Sek Aleksander , Moore Brian C. J.
Published: November 2004

These experiments were designed to test the idea that nonlinearities in the auditory system can introduce a distortion component into the internal representation of the envelope of a sound, and to estimate the phase of the hypothetical distortion component. In experiment 1, a two-alternative forced-choice (2AFC) task with feedback was used to measure psychometric functions for detecting 5-Hz probe modulation of a 4-kHz sinusoidal carrier in the presence of a masker modulator with components at 50 and 55 Hz (m=0.3 for each component). Performance was measured as a function of the relative phase, Δφ, of the probe relative to the “venelope” (envelope of the envelope) of the masker. Performance was poorest for Δφ=135°. In experiment 2, Δφ was fixed at 135°, m was set to 0.48 for each masker component, and psychometric functions for detecting probe modulation were measured using a 2AFC task without feedback. For small probe modulation depths (m≈0.03), the detectability index, d′, was consistently negative, consistent with the existence of a weak distortion product which can “cancel” the probe modulation. The distortion component for the conditions of the experiment was estimated to have a phase of about −25° relative to the venelope.
Noise reduction through source rerouting (L)
Authors: Makarewicz Rufin
Published: November 2004

Rerouting of a moving source can reduce noise exposure. For noise propagation governed by geometrical spreading and air absorption only, a lemniscate minimizes the A-weighted sound exposure. The route minimizing exposure in the presence of geometrical spreading and a simplified model for ground effects is found as well.
Speech perception and talker segregation: Effects of level, pitch, and tactile support with multiple simultaneous talkers
Authors: Drullman Rob , Bronkhorst Adelbert W.
Published: November 2004

Speech intelligibility was investigated by varying the number of interfering talkers, level, and mean pitch differences between target and interfering speech, and the presence of tactile support. In a first experiment the speech-reception threshold (SRT) for sentences was measured for a male talker against a background of one to eight interfering male talkers or speech noise. Speech was presented diotically and vibro-tactile support was given by presenting the low-pass-filtered signal (0–200 Hz) to the index finger. The benefit in the SRT resulting from tactile support ranged from 0 to 2.4 dB and was largest for one or two interfering talkers. A second experiment focused on masking effects of one interfering talker. The interference was the target talker’s own voice with an increased mean pitch by 2, 4, 8, or 12 semitones. Level differences between target and interfering speech ranged from −16 to +4 dB. Results from measurements of correctly perceived words in sentences show an intelligibility increase of up to 27% due to tactile support. Performance gradually improves with increasing pitch difference. Louder target speech generally helps perception, but results for level differences are considerably dependent on pitch differences. Differences in performance between noise and speech maskers and between speech maskers with various mean pitches are explained by the effect of informational masking.
Envelope-onset asynchrony as a cue to voicing in initial English consonants
Authors: Yuan Hanfeng , Reed Charlotte M. , Durlach Nathaniel I.
Published: November 2004

An acoustic cue for voicing is proposed based on the underlying processes associated with the production of the voicing contrast. This cue is based on the time asynchrony between the onsets of two amplitude-envelope signals derived from different bands of speech (i.e., envelopes derived from a lowpass-filtered band at 350 Hz and from a highpass-filtered band at 3000 Hz). Acoustic measurements made on the envelope signals of a set of 16 initial consonants represented through multiple tokens of C1VC2 syllables indicate that the onset-timing difference between the low- and high-frequency envelopes (Envelope-Onset Asynchrony or EOA) provides a reliable and robust cue for distinguishing voiced from voiceless consonants. This cue, which is simply derived in real-time, has applications to the design of sensory aids for persons with profound hearing impairments (e.g., as a supplement to lipreading), as well as to automatic speech recognition.
Frequency-place compression and expansion in cochlear implant listeners
Authors: Başkent Deniz , Shannon Robert V.
Published: November 2004

In multichannel cochlear implants, low frequency information is delivered to apical cochlear locations while high frequency information is delivered to more basal locations, mimicking the normal acoustic tonotopic organization of the auditory nerves. In clinical practice, little attention has been paid to the distribution of acoustic input across the electrodes of an individual patient that might vary in terms of spacing and absolute tonotopic location. In normal-hearing listeners, Başkent and Shannon (J. Acoust. Soc. Am. 113, 2003) simulated implant signal processing conditions in which the frequency range assigned to the array was systematically made wider or narrower than the simulated stimulation range in the cochlea, resulting in frequency-place compression or expansion, respectively. In general, the best speech recognition was obtained when the input acoustic information was delivered to the matching tonotopic place in the cochlea with least frequency-place distortion. The present study measured phoneme and sentence recognition scores with similar frequency-place manipulations in six Med-El Combi 40+ implant subjects. Stimulation locations were estimated using the Greenwood mapping function based on the estimated electrode insertion depth. Results from frequency-place compression and expansion with implants were similar to simulation results, especially for postlingually deafened subjects, despite the uncertainty in the actual stimulation sites of the auditory nerves. The present study shows that frequency-place mapping is an important factor in implant performance and an individual implant patient’s map could be optimized with functional tests using frequency-place manipulations.
A TWO-DIMENSIONAL DYNAMIC SIMULATION OF SOLID FRACTURE PART I: DESCRIPTION OF THE MODEL
Authors: POTAPOV ALEXANDER V. , HOPKINS MARK A. , CAMPBELL CHARLES S.
Published: November 2004

This paper describes a two-dimensional computer simulation of solid fracture that allows the body and the fragments to be followed well beyond the point of simple crack formation. The model is based on discrete particle computer simulations used for studying granular flows. Here, macroscopic polygonal solid are constructed by “gluing” together small elements. Depending on the stress conditions the glued bonds between the elements can respond elastically, undergo plastic failure or break, allowing cracks to propagate across the macroscopic particle along the boundaries between their microscopic constituents. In essence, this process creates a simulated material upon which breakage occurs. Several element shapes have been studied.
A SCHRÖDINGER EQUATION FOR MINIUNIVERSES
Authors: CAVAGLIÀ MARCO , DE ALFARQ VITTORIO , FILIPPOV ALEXANDRE T.
Published: November 2004

We discuss how to fix the gauge in the canonical treatment of Lagrangians, with a finite number of degrees of freedom, endowed with time reparametrization invariance. The motion can be described by an effective Hamiltonian acting on the gauge shell canonical space. The system is then suited for quantization. We apply this treatment to the case of a Robertson–Walker metric interacting with zero modes of bosonic fields and write a Schrödinger equation for the on-shell wave function.
ON COLOR QUANTIZATION: RELATIONS AND PARASTATISTICS
Authors: MARCINEK WŁADYSŁAW
Published: November 2004

Particle operators for the description of a system of families of particles of different kind are introduced. The generalized commutators and Klein transformations are discussed in some detail. The color description of parastatistics is given.
NORMALIZATION OF THE WAVEFUNCTION FOR THE CALOGERO-SUTHERLAND MODEL WITH INTERNAL DEGREES OF FREEDOM
Authors: FORRESTER P.J.
Published: November 2004

The exact normalization of a multicomponent generalization of the ground state wave-function of the Calogero-Sutherland model is conjectured. This result is obtained from a conjectured generalization of Selberg’s N-dimensional extension of the Euler beta integral, written as a trigonometric integral. A new proof of the Selberg integral is given, and the method is used to provide a proof of the multicomponent generalization in a special two-component case.
GROUND-STATE ENERGY OF THE ONE-DIMENSIONAL HUBBARD MODEL IN A SIMPLE SELF-CONSISTENT VERSION OF THE LADDER APPROXIMATION
Authors: BUZATU F.D.
Published: November 2004

The ground-state energy of the one-dimensional Hubbard model is calculated within the ladder approximation; from the comparison with the exact results in the repulsive case, it follows that the approximation is good at low densities or small couplings. The ladder approximation can be improved by imposing a self-consistency condition; using a simple assumption, the results become close to the exact ones in a large range of the model parameters.
124 K SUPERCONDUCTIVITY IN Cu-Ba-Ca-Cu-O
Authors: GAO L. , DU Z. L. , CAO Y. , RUSAKOVA I. , SUN Y. Y. , XUE Y. Y. , CHU C. W.
Published: November 2004

A superconducting phase with a transition temperature up to 124 K has been detected in multiphase samples of Cu-Ba-Ca-Cu-O synthesized under pressures between 5.5 and 6 GPa and at temperatures between 820 and 870°C. The 124 K transition is attributed to a phase closely related to CuBa 2 Ca n−1 Cu n O y, which is known to be superconducting only below 117 K, with a possible subtle change in the local atomic arrangement or stoichiometry. Structure details and the optimal synthesis conditions of the 124 K phase have yet to be determined.
INTERACTING FERMIONS, SCALING AND POSSIBLE DEPARTURE FROM FERMI LIQUID BEHAVIOR
Authors: CHAUDHURY RANJAN , GANGOPADHYAY DEBASHIS
Published: November 2004

We study fermionic models with realistic interaction in the low energy limit by scaling energies. We show that there exist possibilities for a departure from the Fermi liquid picture in two dimensions.
INTERMEDIATE NUMBER-SQUEEZED STATE OF THE QUANTIZED RADIATION FIELD
Authors: BASEIA B. , DE LIMA A.F. , DA SILVA A.J.
Published: November 2004

Following previous strategies by Stoler et al. which introduced the binomial state and Baseia et al. which introduced the intermediate number phase state, we introduce a new intermediate state of the quantized radiation field, which reduces to the number state and squeezed state in two different limits. This interpolating state exhibits nonclassical effects as sub-Poissonian, antibunching and squeezing, obtained from the corresponding expressions as function of the interpolating parameters.
CONFORMAL COUPLING AND INVARIANCE IN DIFFERENT DIMENSIONS
Authors: RAINER MARTIN
Published: November 2004

Conformal transformations of the following kinds are compared: (1) conformal coordinate transformations, (2) conformal transformations of Lagrangian models for a D-dimensional geometry, given by a Riemannian manifold M with metric g of arbitrary signature, and (3) conformal transformations of (mini-)superspace geometry. For conformal invariance under these transformations the following applications are given respectively: (1) Natural time gauges for multidimensional geometry, (2) conformally equivalent Lagrangian models for geometry coupled to a spatially homogeneous scalar field, and (3) the conformal Laplace operator on the n-dimensional manifold ℳ of minisuperspace for multidimensional geometry and the Wheeler-de Witt equation.

The conformal coupling constant ξc is critically distinguished among arbitrary couplings ξ, for both, the equivalence of Lagrangian models with D-dimensional geometry and the conformal geometry on n-dimensional minisuperspace.

For dimension D=3, 4, 6 or 10, the critical number [Formula: see text] is especially simple as a rational fraction.
CELL CYCLE AS AN OBJECT OF CONTROL
Authors: ŚWIERNIAK ANDRZEJ
Published: November 2004

This paper is a review of mathematical models of control of cell cycle dynamics using external agents which take into account cell-cycle-phase specificity of the drugs. Although still far from being ready for clinical usage the results of these investigations give a new insight into difficulties in introduction of effective strategies in the war against cancer.
MATHEMATICAL MODELLING OF CANCER TREATMENT WITH PHASE-SPECIFIC CYTOTOXIC AGENTS
Authors: DIBROV B.F.
Published: November 2004

The goal of this study is the development of treatment schedules with increased selectivity in killing malignant cells as opposed to normal cells. The optimization is carried out on the basis of the mathematical model. The model describes the dynamics of proliferating cell population under in vivo periodic treatment with high doses of a phase-specific agent. On the basis of the model the effectiveness of various treatment schedules have been studied and optimal ones have been designed. When the mean cell-cycle times of normal and tumors cells differ significantly (as it is true for most natural tumors) the optimal schedules make it possible to increase considerably the selectivity of the treatment and to achieve important therapeutic benefit.
DYNAMIC FEEDBACK AND THE DESIGN OF CLOSED-LOOP DRUG DELIVERY SYSTEMS
Authors: MILTON JOHN , CAMPBELL SUE ANN , BÉLAIR JACQUES
Published: November 2004

A closed-loop drug delivery system is constructed in which external negative feedback is used to regulate the dynamics of a time-delayed negative feedback mechanism which regulates hormone concentration. This results in a control system composed of two time-delayed negative feedback loops arranged in parallel. Stability regions in parameter space and the location of steady states are determined for the cases when the time delays are equal and when they are unequal. The advantage of this paradigm for drug delivery is that both the steady states and stability of the multiple loop feedback system can be influenced in a precisely controllable manner.
BASIC MORPHOGENETIC SYSTEM MODELING SHAPE CHANGES OF MIGRATING CELLS: HOW TO EXPLAIN FLUCTUATING LAMELLIPODIAL DYNAMICS
Authors: ALT WOLFGANG , TRANQUILLO ROBERT T.
Published: November 2004

Migration of cells as leukocytes (white blood cells) or keratinocytes (outer epidermic cells) plays an important role in the response of (human) organisms to infections or injuries. When placed on two-dimensional substrata, these cells show extensive protrusions of so-called lamellipods, mostly around the whole cell periphery, inducing characteristic shape changes of the cell outline and subsequent translocation of the cell body.

In order to explain the observed lamellipodial dynamics we investigate a "circular" model describing radial extension, L(t, x), of the cell periphery and density, a(t, x), of the underlying cortical polymer layer, consisting of actin and myosin filaments, as well as their contractile activity and their tangential transport velocity v(t, x). The resulting differential equations constitute a system of a non-local hyperbolic transport equation for a on the unit circle combined with a parabolic equation for L. Linear stability analysis as well as numerical simulations provide characteristic "morphogenetic behavior" of this model system, typically showing spatio-temporal patterns with one, two or more protrusions. One important feature of this morphogenetic system on the unit circle is the simple fact that stationary patterns might appear, but are stable only up to rotational shifts.

This feature becomes effective, if we introduce stochastic perturbations of the PDE system, e.g. by adding a spatio-temporally correlated Gauss process to the rate term for actin assembly (thought to be induced by fluctuations of bound chemo-receptors which diffuse in the cell membrane). Then, depending on the choice of parameters, typical protrusion patterns transiently appear, or remain but are shifted circumferentially. Characteristic spatio-temporal auto-correlation results for these "model cells" can be compared to corresponding statistical results for "real cells".
Large deviations for exchangeable observations with applications
Authors: Chen Jinwen
Published: November 2004

We first prove some large deviation results for a mixture of i.i.d. random variables. Compared with most of the known results in the literature, our results are built on relaxing some restrictive conditions that may not be easy to be checked in certain typical cases. The main feature in our main results is that we require little knowledge of (continuity of) the component measures and/or of the compactness of the support of the mixing measure. Instead, we pose certain moment conditions, which may be more practical in applications. We then use the large deviation approach to study the problem of estimating the component and the mixing measures.
Absolutely continuous measures and compact composition operator on spaces of Cauchy transforms
Authors: Abu Muhanna Yusuf , Yallaoui El-Bachir
Published: November 2004

The analytic self‐map of the unit disk D, φ is said to induce a composition operator Cφ from the Banach space X to the Banach space Y if Cφ(f) = f∘φ ∈ Y for all f ∈ X. For z ∈ D and α > 0, the families of weighted Cauchy transforms Fα are defined by , where μ(x) is complex Borel measure, x belongs to the unit circle T, and the kernel . In this paper, we will explore the relationship between the compactness of the composition operator Cφ acting on Fα and the complex Borel measures μ(x).
The structure of a subclass of amenable banach algebras
Authors: El Harti R.
Published: November 2004

We give sufficient conditions that allow contractible (resp., reflexive amenable) Banach algebras to be finite‐dimensional and semisimple algebras. Moreover, we show that any contractible (resp., reflexive amenable) Banach algebra in which every maximal left ideal has a Banach space complement is indeed a direct sum of finitely many full matrix algebras. Finally, we characterize Hermitian  *‐algebras that are contractible.
Classes of uniformly starlike and convex functions
Authors: Shams Saeid , Kulkarni S. R. , Jahangiri Jay M.
Published: November 2004

Some classes of uniformly starlike and convex functions are introduced. The geometrical properties of these classes and their behavior under certain integral operators are investigated.
Interaction between the Polyol Pathway and Non-Enzymatic Glycation on Mesangial Cell Gene Expression
Authors: Dan Qinghong , Wong Rachel L.C. , Yin Shinan , Chung Sookja K. , Chung Stephen S.M. , Lam Karen S.L.
Published: November 2004

Background/Aims: Both activation of the polyol pathway and enhanced non-enzymatic glycation have been implicated in the pathogenesis of diabetic glomerulopathy. We investigated the interaction between these two pathways using normal mesangial cells (MCs) and transgenic (TG) MCs with elevated aldose reductase (AR) activity. Methods: TG mice with expression of the human AR (hAR) gene in kidney MCs were established. Mouse glomeruli and primary cultures of MCs from hAR TG and wild-type (WT) mice were studied regarding the changes in AR activity, transforming growth factor-β1 (TGF-β1) and type IV collagen mRNA and protein levels, in response to BSA modified by advanced glycation end-products (AGE-BSA). Results: Ex vivo addition of AGE-BSA increased AR activity, TGF-β1 and type IV collagen mRNA levels in both WT and TG glomeruli, with greater rise in TG glomeruli. These increments were attenuated by zopolrestat, an AR inhibitor. In cultured MCs, AGE-BSA enhanced AR activity, TGF-β1 and type IV collagen mRNA and protein levels both in WT and TG MCs, again with greater increases in TG MCs. The AGE-induced enhancement in TGF-β1 and type IV collagen expression were suppressed by either zopolrestat or transfection with an AR antisense oligonucleotide. Conclusion: These data suggest that the activation of the polyol pathway by AGEs, more marked in genetic conditions with increased AR activity, may contribute to the pathogenesis of diabetic glomerulopathy, through enhancing mesangial cell expression of TGF-β1 and type IV collagen.
DNA damage in bronchial epithelial and mesothelial cells with and without associated crocidolite asbestos fibers
Authors: Nygren Jonas , Suhonen Satu , Norppa Hannu , Linnainmaa Kaija
Published: November 2004

Mesothelioma is induced almost exclusively by exposure to asbestos fibers. We have investigated whether the induction of DNA damage in human bronchial epithelial BEAS 2B cells and human mesothelial MeT 5A cells by crocidolite asbestos (2 μg/cm2) requires the presence of asbestos fibers in the cells. DNA damage was measured microscopically by the Comet assay, and the presence of fibers in the same cells was assessed using bright‐field illumination. After treatment times of 6–72 hr, damage levels were, on the average, two times higher in cells with fibers than in cells without fibers. It was further found that DNA damage decreased with time in BEAS 2B cells both with and without fibers. No decrease in damage with time was seen in MeT 5A cells, suggesting that these mesothelial cells repair the initial damage poorly, lack induction of protective systems, or constantly produce high levels of damaging species. Our results indicate that crocidolite‐treated human mesothelial MeT 5A and bronchial epithelial BEAS 2B cells show an elevated level of DNA damage if they contain a fiber. In comparison with epithelial BEAS 2B cells, mesothelial MeT 5A cells have more DNA damage after the crocidolite treatment and the damage is more persistent. Environ. Mol. Mutagen., 2004. © 2004 Wiley‐Liss, Inc.
PTCH polymorphism is associated with the rate of increase in basal cell carcinoma numbers during follow‐up: Preliminary data on the influence of an exon 12‐exon 23 haplotype
Authors: Strange Richard C. , El‐Genidy Noha , Ramachandran Sudarshan , Lovatt Tracy J. , Fryer Anthony A. , Smith Andrew G. , Lear John T. , Ichii‐Jones Fumiyo , Jones Peter W. , Hoban Paul R.
Published: November 2004

After first presentation with a basal cell carcinoma (BCC), patients demonstrate interindividual diversity in the rate of development of further BCCs (number/year of follow‐up). The mechanism for this variation is unknown. In this study, we evaluated whether PTCH variants mediate this phenomenon. We used negative binomial regression analysis to identify associations between BCC numbers/year and host characteristics, parameters of exposure to ultraviolet radiation (UVR), and PTCH exon 121686 C/T, intron 152560+9 G/C, and exon 233944 C/T genotypes and haplotypes in 279 BCC cases who presented with an initial tumor on the head/neck. PTCH genotypes were not significantly associated with BCCs/year, although cases with two copies of the C1686‐C3944 haplotype developed significantly fewer BCCs/year than those without this haplotype (rate ratio = 0.44; 95% CI = 0.27–0.71). Cases with one copy of T1686‐T3944 developed more BCCs/year (rate ratio = 2.46; 95% CI = 1.27–3.97) than those without the haplotype. We found no significant associations between BCCs/year and the other PTCH haplotypes studied. We reexamined the association of C1686‐C3944 with BCCs/year in a model that included UVR exposure parameters (sunburning in childhood, sunbathing score, intermittency of exposure between 40 and 60 years of age, exposure in hours/year) and skin type, gender, and age at first presentation. The association between C1686‐C3944 and BCCs/year remained significant (rate ratio = 0.44; 95% CI = 0.26–0.73 for two copies of the haplotype). The data show that allelic variation in PTCH contributes to the rate of development of BCC. Environ. Mol. Mutagen., 2004. © 2004 Wiley‐Liss, Inc.
Histone deacetylase inhibitors suppress telomerase reverse transcriptase mrna expression in prostate cancer cells
Authors: Suenaga Mitsuhiro , Soda Hiroshi , Oka Mikio , Yamaguchi Akihiko , Nakatomi Katsumi , Shiozawa Ken , Kawabata Shigeru , Kasai Takashi , Yamada Yasuaki , Kamihira Shimeru , Tei Chuwa , Kohno Shigeru
Published: November 2004

Telomerase activity is involved in cellular immortality. We have recently demonstrated that telomerase activity is closely associated with cell proliferation in prostate cancers. Telomerase is composed primarily of the catalytic subunit (hTERT) and the RNA template (hTERC), and hTERT expression is regulated by several factors such as c‐MYC and p21Waf1. Histone deacetylase (HDAC) inhibitors are known to modulate transcription and exhibit antiproliferative effects on cancer cells. The present study was designed to evaluate the effects of HDAC inhibitors on hTERT mRNA expression in prostate cancer cells. LNCaP and PC‐3 cells were treated with HDAC inhibitors, trichostatin A (TSA) and sodium butyrate (NaB); mRNA expression and telomerase activity were evaluated by RT‐PCR and the TRAP assay, respectively. In LNCaP cells, hTERT mRNA expression was suppressed at 1 and 3 hr after treatment with 1 μM TSA and 4 mM NaB, respectively, followed by inhibition of telomerase activity. The inhibition of hTERT mRNA expression preceded suppression of cell proliferation. In PC‐3 cells, TSA and NaB also inhibited cell proliferation, hTERT mRNA expression and telomerase activity. In both cell lines, TSA and NaB had no effect on hTERC expression, or on expression of c‐myc and p21Waf1 mRNA. These effects of TSA and NaB were unlikely to be consequences of cell cycle arrest, apoptosis, or cell differentiation. Thus, HDAC inhibitors down‐regulated telomerase activity via suppression of hTERT mRNA expression. Our study identified a novel mechanism for the antiproliferative effects of HDAC inhibitors on prostate cancer cells. © 2001 Wiley‐Liss, Inc.