bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensory evaluation: age and gender profiling of lite, no‐sugar‐added vanilla ice creams
Authors: Stokols Jennifer , Bordi Peter , Palchak Tom , Lee H. Andy
Published: April 2006

This study is the third in a series of research studies aimed at profiling both genders and two distinct age groups for sensory preferences of no sugar added vanilla ice creams. A sample of two hundred participants tasted and rated three samples of market‐available lite, no‐sugar‐added vanilla ice creams (which contain a mixture, or formulation, of several sweetening agents) against the control version (which only includes maltitol as the sweetening agent). Participants used a nine‐point hedonic scale to indicate their preference for various attributes noted in both products. The four samples differed in their sugar content, fat content (though all were under 3 grams per half cup serving by definition of “lite”), and fiber content but had similar calorie and protein profiles. Participants were categorized into one of four groups for data compilation and interpretation: male students, female students, male adults, and female adults. They used computer software to complete questionnaires, and the results were tabulated by the physical attributes (i.e., taste, texture, and appearance) as well as by overall impressions of the sensory characteristics of the four samples as means for comparison. The results of the study concurred with past findings regarding overall consumer acceptability of the no‐sugar‐added ice cream. The results suggested that, for the student and adult population tested, a maltitol syrup with these characteristics is the ideal sweetener used in light no‐sugar‐added frozen desserts and would be an appropriate focus for future product manipulation by food manufacturers and marketers, alike.
Street‐level bureaucrats and the implementation of cleaning and sanitation practices in foodservice: case findings from a study in Danish hospitals and nursing homes
Authors: Mikkelsen Bent E. , Søndergård Kristine G.
Published: April 2006

Proper cleaning and sanitation that can to maintain the sanitary and hygienic level in the catering kitchens is an important routine to prevent food‐borne diseases and good management of cleaning and sanitation is an important part of any hygiene management system. But large scale industrial kitchens in general seems to be quite slow in initiating change processes required to implementing new routines and only very few large industrial kitchens in Denmark had compulsory self‐inspection programs or auto‐control operating as required. Against this background a study was carried out in Danish institutional kitchens to study the implementation process of cleaning and sanitation practices at practitioner level. The aim of the study was to study how policies aiming at improving hygiene management in foodservice have been implemented at kitchen level when it comes to cleaning and sanitation. The study was conducted as a multiple case study in nursing home and hospital kitchens. The methodology was based on individual telephone interviews in combination with a quantitative questionnaire. A total of 15 kitchens participated in the study which were based on and open‐ended interview guide, focusing on applied cleaning methods, principles for choice of cleaning procedures and methods, cleaning management, including existing documentation for cleaning quality, as well as suggestions for improvements and advancements in cleaning and sanitation. The study shows that street‐level bureaucrats responsible for cleaning and sanitation feel themselves faced with number of challenges that they don’t have the right background to be able to handle properly and this is mirrored in their views and attitudes towards cleaning and sanitation. Street‐level bureaucrats find: that cleaning and sanitation is boring, monotonous and has low status; that help and guidelines for implementing their self‐inspection program is needed; that planning and management tools and techniques are lacking; that tacit knowledge is the guiding principle rather than written procedures; and that educational opportunities are lacking and that there are few opportunities for networking and sharing of knowledge. In general street‐level bureaucrats responsible for cleaning and sanitation feel themselves faced with number of challenges that they don’t have the right background to be able to handle properly and this is mirrored in their views and attitudes towards cleaning and sanitation.
Composition-Modified Matrices Improve Identification of Homologs of
Saccharomyces cerevisiae
Low-Complexity Glycoproteins
Authors: Coronado Juan E. , Attie Oliver , Epstein Susan L. , Qiu Wei-Gang , Lipke Peter N.
Published: April 2006

Yeast glycoproteins are representative of low-complexity sequences, those sequences rich in a few types of amino acids. Low-complexity protein sequences comprise more than 10% of the proteome but are poorly aligned by existing methods. Under default conditions, BLAST and FASTA use the scoring matrix BLOSUM62, which is optimized for sequences with diverse amino acid compositions. Because low-complexity sequences are rich in a few amino acids, these tools tend to align the most common residues in nonhomologous positions, thereby generating anomalously high scores, deviations from the expected extreme value distribution, and small
e
values. This anomalous scoring prevents BLOSUM62-based BLAST and FASTA from identifying correct homologs for proteins with low-complexity sequences, including
Saccharomyces cerevisiae
wall proteins. We have devised and empirically tested scoring matrices that compensate for the overrepresentation of some amino acids in any query sequence in different ways. These matrices were tested for sensitivity in finding true homologs, discrimination against nonhomologous and random sequences, conformance to the extreme value distribution, and accuracy of
e
values. Of the tested matrices, the two best matrices (called E and gtQ) gave reliable alignments in BLAST and FASTA searches, identified a consistent set of paralogs of the yeast cell wall test set proteins, and improved the consistency of secondary structure predictions for cell wall proteins.
Low Genetic Variation and No Detectable Population Structure in
Aspergillus fumigatus
Compared to Closely Related
Neosartorya
Species
Authors: Rydholm Carla , Szakacs George , Lutzoni François
Published: April 2006

Aspergillus fumigatus
is an anamorphic euascomycete mold with a ubiquitous presence worldwide. Despite intensive work to understand its success as a pathogen infecting immunosuppressed patients, the population dynamics and recent evolutionary history of
A. fumigatus
remain understudied. We examined patterns of genetic variation at three intergenic loci for 70 natural isolates from Europe, North America, South America, Asia, Africa, and Australia. The same loci were used to analyze within-population genetic variation for 33 isolates obtained from five geographic locations. Neither data set detected evidence of population differentiation or found any association between the genetic and geographic distances among these isolates. No evidence for genetic differentiation within the two
A. fumigatus
mating types was detected. The genetic diversity of
A. fumigatus
, contrasted with that of its close teleomorphic relatives,
Neosartorya fischeri
and
Neosartorya spinosa
, is remarkably low.
Acanthamoeba castellaniiPromotion of In Vitro Survival and Transmission of Coxsackie B3 Viruses
Authors: Mattana A. , Serra C. , Mariotti E. , Delogu G. , Fiori P. L. , Cappuccinelli P.
Published: April 2006

This work was undertaken to determine whetherAcanthamoebacould play a role in the survival and transmission of coxsackieviruses and focused on in vitro interactions betweenAcanthamoeba castellaniiand coxsackie B3 viruses (CVB-3). Residual virus titer evaluations and immunofluorescence experiments revealed a remarkable CVB-3 adsorption on amoeba surfaces and accumulation inside cells. The survival of viruses was independent of the dynamics of amoeba replication and encystment. In addition, our results indicated that virus-infected amoebas can release infectious viruses during interaction with human macrophages. On the basis of these data,Acanthamoebaappears to be a potential promoter of the survival of coxsackieviruses and their transmission to human hosts.
High-Mobility-Group Box Nuclear Factors of
Plasmodium falciparum
Authors: Briquet Sylvie , Boschet Charlotte , Gissot Mathieu , Tissandié Emilie , Sevilla Elisa , Franetich Jean-François , Thiery Isabelle , Hamid Zuhal , Bourgouin Catherine , Vaquero Catherine
Published: April 2006

In eukaryotes, the high-mobility-group (HMG) nuclear factors are highly conserved throughout evolution and are divided into three families, including HGMB, characterized by an HMG box domain. Some HMGB factors are DNA structure specific and preferentially interact with distorted DNA sequences, trigger DNA bending, and hence facilitate the binding of nucleoprotein complexes that in turn activate or repress transcription. In
Plasmodium falciparum
, two HMGB factors were predicted: PfHMGB1 and PfHMGB2. They are small proteins, under 100 amino acids long, encompassing a characteristic HMG box domain closely related to box B of metazoan factors, which comprises two HMG box domains, A and B, in tandem. Computational analyses supported the conclusion that the
Plasmodium
proteins were genuine architectural HMGB factors, and in vitro analyses performed with both recombinant proteins established that they were able to interact with distorted DNA structures and bend linear DNA with different affinities. These proteins were detected in both asexual- and gametocyte-stage cells in Western blotting experiments and mainly in the parasite nuclei. PfHMGB1 is preferentially expressed in asexual erythrocytic stages and PfHMGB2 in gametocytes, in good correlation with transcript levels of expression. Finally, immunofluorescence studies revealed differential subcellular localizations: both factors were observed in the nucleus of asexual- and sexual-stage cells, and PfHMGB2 was also detected in the cytoplasm of gametocytes. In conclusion, in light of differences in their levels of expression, subcellular localizations, and capacities for binding and bending DNA, these factors are likely to play nonredundant roles in transcriptional regulation of
Plasmodium
development in erythrocytes.
Ras GTPase-Activating Protein Gap1 of the Homobasidiomycete
Schizophyllum commune
Regulates Hyphal Growth Orientation and Sexual Development
Authors: Schubert Daniela , Raudaskoski Marjatta , Knabe Nicole , Kothe Erika
Published: April 2006

The white rot fungus
Schizophyllum commune
is used for the analysis of mating and sexual development in homobasidiomycete fungi. In this study, we isolated the gene
gap1
encoding a GTPase-activating protein for Ras. Disruption of
gap1
should therefore lead to strains accumulating Ras in its activated, GTP-bound state and to constitutive Ras signaling. Haploid
Δgap1
monokaryons of different mating types did not show alterations in mating behavior in the four different mating interactions possible in fungi expressing a tetrapolar mating type system. Instead, the growth rate in
Δgap1
monokaryons was reduced by ca. 25% and ca. 50% in homozygous
Δgap1
/
Δgap1
dikaryons. Monokaryons, as well as homozygous dikaryons, carrying the disrupted
gap1
alleles exhibited a disorientated growth pattern. Dikaryons showed a strong phenotype during clamp formation since hook cells failed to fuse with the peg beside them. Instead, the dikaryotic character of the hyphae was rescued by fusion of the hooks with nearby developing branches.
Δgap1
/
Δgap1
dikaryons formed increased numbers of fruitbody primordia, whereas the amount of fruitbodies was not raised. Mature fruitbodies formed no or abnormal gills. No production of spores could be observed. The results suggest Ras involvement in growth, clamp formation, and fruitbody development.
Flagellar Motility Contributes to Cytokinesis inTrypanosoma bruceiand Is Modulated by an Evolutionarily Conserved Dynein Regulatory System
Authors: Ralston Katherine S. , Lerner Alana G. , Diener Dennis R. , Hill Kent L.
Published: April 2006

The flagellum ofTrypanosoma bruceiis a multifunctional organelle with critical roles in motility and other aspects of the trypanosome life cycle. Trypanin is a flagellar protein required for directional cell motility, but its molecular function is unknown. Recently, a trypanin homologue inChlamydomonas reinhardtiiwas reported to be part of a dynein regulatory complex (DRC) that transmits regulatory signals from central pair microtubules and radial spokes to axonemal dynein. DRC genes were identified as extragenic suppressors of central pair and/or radial spoke mutations. We used RNA interference to ablate expression of radial spoke (RSP3) and central pair (PF16) components individually or in combination with trypanin. Bothrsp3andpf16single knockdown mutants are immotile, with severely defective flagellar beat. In the case ofrsp3, this loss of motility is correlated with the loss of radial spokes, while in the case ofpf16the loss of motility correlates with an aberrant orientation of the central pair microtubules within the axoneme. Genetic interaction between trypanin and PF16 is demonstrated by the finding that loss of trypanin suppresses thepf16beat defect, indicating that the DRC represents an evolutionarily conserved strategy for dynein regulation. Surprisingly, we discovered that four independent mutants with an impaired flagellar beat all fail in the final stage of cytokinesis, indicating that flagellar motility is necessary for normal cell division inT. brucei. These findings present the first evidence that flagellar beating is important for cell division and open the opportunity to exploit enzymatic activities that drive flagellar beat as drug targets for the treatment of African sleeping sickness.
Endoplasmic Reticulum-Associated Degradation Is Required for Cold Adaptation and Regulation of Sterol Biosynthesis in the Yeast
Saccharomyces cerevisiae
Authors: Loertscher Jennifer , Larson Lynnelle L. , Matson Clinton K. , Parrish Mark L. , Felthauser Alicia , Sturm Aaron , Tachibana Christine , Bard Martin , Wright Robin
Published: April 2006

Endoplasmic reticulum-associated degradation (ERAD) mediates the turnover of short-lived and misfolded proteins in the ER membrane or lumen. In spite of its important role, only subtle growth phenotypes have been associated with defects in ERAD. We have discovered that the ERAD proteins Ubc7 (Qri8), Cue1, and Doa10 (Ssm4) are required for growth of yeast that express high levels of the sterol biosynthetic enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Interestingly, the observed growth defect was exacerbated at low temperatures, producing an HMGR-dependent cold sensitivity. Yeast strains lacking
UBC7
,
CUE1
, or
DOA10
also assembled aberrant karmellae (ordered arrays of membranes surrounding the nucleus that assemble when HMGR is expressed at high levels). However, rather than reflecting the accumulation of abnormal karmellae, the cold sensitivity of these ERAD mutants was due to increased HMGR catalytic activity. Mutations that compromise proteasomal function also resulted in cold-sensitive growth of yeast with elevated HMGR, suggesting that improper degradation of ERAD targets might be responsible for the observed cold-sensitive phenotype. However, the essential ERAD targets were not the yeast HMGR enzymes themselves. The sterol metabolite profile of
ubc7Δ
cells was altered relative to that of wild-type cells. Since sterol levels are known to regulate membrane fluidity, the viability of ERAD mutants expressing normal levels of HMGR was examined at low temperatures. Cells lacking
UBC7
,
CUE1
, or
DOA10
were cold sensitive, suggesting that these ERAD proteins have a role in cold adaptation, perhaps through effects on sterol biosynthesis.
Phosphoinositide 5-Phosphatase Fig4p Is Required for both Acute Rise and Subsequent Fall in Stress-Induced Phosphatidylinositol 3,5-Bisphosphate Levels
Authors: Duex Jason E. , Nau Johnathan J. , Kauffman Emily J. , Weisman Lois S.
Published: April 2006

Phosphoinositide lipids regulate complex events via the recruitment of proteins to a specialized region of the membrane at a specific time. Precise control of both the synthesis and turnover of phosphoinositide lipids is integral to membrane trafficking, signal transduction, and cytoskeletal rearrangements. Little is known about the acute regulation of the levels of these signaling lipids. When
Saccharomyces cerevisiae
cells are treated with hyperosmotic medium the levels of phosphatidylinositol 3,5-bisphosphate (PI3,5P
2
) increase 20-fold. Here we show that this 20-fold increase is rapid and occurs within 5 min. Surprisingly, these elevated levels are transient. Fifteen minutes following hyperosmotic shock they decrease at a rapid rate, even though the cells remain in hyperosmotic medium. In parallel with the rapid increase in the levels of PI3,5P
2
, vacuole volume decreases rapidly. Furthermore, concomitant with a return to basal levels of PI3,5P
2
vacuole volume is restored. We show that Fig4p, consistent with its proposed role as a PI3,5P
2
5-phosphatase, is required in vivo for this rapid return to basal levels of PI3,5P
2
. Surprisingly, we find that Fig4p is also required for the hyperosmotic shock-induced increase in PI3,5P
2
levels. These findings demonstrate that following hyperosmotic shock, large, transient changes occur in the levels of PI3,5P
2
and further suggest that Fig4p is important in regulating both the acute rise and subsequent fall in PI3,5P
2
levels.
Activation of Zoosporogenesis-Specific Genes in
Phytophthora infestans
Involves a 7-Nucleotide Promoter Motif and Cold-Induced Membrane Rigidity
Authors: Tani Shuji , Judelson Howard
Published: April 2006

Infections of plants by the oomycete
Phytophthora infestans
typically result from zoospores, which develop from sporangia at cold temperatures. To help understand the relevant cold-induced signaling pathway, factors regulating the transcription of the zoosporogenesis-specific NIF (nuclear LIM-interactor-interacting factor) gene family were examined. Sequences required for inducing
PinifC3
were identified by analyzing truncated and mutated promoters using the β-glucuronidase reporter in stable transformants. A 7-nucleotide (nt) sequence located 139 bases upstream of the major transcription start point (GGACGAG) proved essential for the induction of
PinifC3
when sporangia were shifted from ambient to cold temperatures. The motif, named the cold box, also conferred cold inducibility to a promoter normally activated only during sexual development. An identical motif was detected in the two other zoosporogenesis-specific NIF genes from
P. infestans
and three
Phytophthora sojae
orthologues, and a closely related sequence was found in
Phytophthora ramorum
orthologues. The 7-nt motif was also found in the promoters of other zoosporogenesis-induced genes. The presence of a cold box-interacting protein in nuclear extracts of
P. infestans
sporangia was demonstrated using electrophoretic mobility shift assays. Furthermore, zoospore release and cold box-regulated transcription were stimulated by the membrane rigidizer dimethyl sulfoxide and inhibited by the membrane fluidizer benzyl alcohol. The data therefore delineate a pathway in which sporangia perceive cold temperatures through membrane rigidity, which activates signals that drive both zoosporogenesis and cold-box-mediated transcription.
Specific Effects of Ribosome-Tethered Molecular Chaperones on Programmed −1 Ribosomal Frameshifting
Authors: Muldoon-Jacobs Kristi L. , Dinman Jonathan D.
Published: April 2006

The ribosome-associated molecular chaperone complexes RAC (Ssz1p/Zuo1p) and Ssb1p/Ssb2p expose a link between protein folding and translation. Disruption of the conserved nascent peptide-associated complex results in cell growth and translation fidelity defects. To better understand the consequences of deletion of either RAC or Ssb1p/2p, experiments relating to cell growth and programmed ribosomal frameshifting (PRF) were assayed. Genetic analyses revealed that deletion of Ssb1p/Ssb2p or of Ssz1p/Zuo1p resulted in specific inhibition of −1 PRF and defects in Killer virus maintenance, while no effects were observed on +1 PRF. These factors may provide a new set of targets to exploit against viruses that use −1 PRF. Quantitative measurements of growth profiles of isogenic wild-type and mutant cells showed that translational inhibitors exacerbate underlying growth defects in these mutants. Previous studies have identified −1 PRF signals in yeast chromosomal genes and have demonstrated an inverse relationship between −1 PRF efficiency and mRNA stability. Analysis of published DNA microarray experiments reveals conditions under which Ssb1, Ssb2, Ssz1, and Zuo1 transcript levels are regulated independently of those of genes encoding ribosomal proteins. Thus, the findings presented here suggest that these
trans
-acting factors could be used by cells to posttranscriptionally regulate gene expression through −1 PRF.
Cardiolipin in Hydrogenosomes: Evidence of Symbiotic Origin
Authors: de Andrade Rosa Ivone , Einicker-Lamas Marcelo , Roney Bernardo Róbson , Previatto Lucia Mendonça , Mohana-Borges Ronaldo , Morgado-Díaz José Andrés , Benchimol Marlene
Published: April 2006

Hydrogenosomes are found in organisms that lack typical mitochondria. Cardiolipin is a phospholipid located exclusively in bacterial membranes and the inner membrane of mitochondria. Here we show, by cell fractionation, thin-layer chromatography, high-pressure liquid chromatography, and matrix-assisted laser desorption ionization-time of flight mass spectrometry that hydrogenosomes of
Tritrichomonas foetus
, a cattle vaginal parasite, contain cardiolipin, which is strong evidence for its endosymbiotic origin.
MAGNETIC BEHAVIOR OF Al2GdNi COMPOUND
Authors: COLDEA M. , POP V. , PASCUT L. G. , TODORAN D. , PACURARIU R.
Published: April 2006

The magnetic properties of Al 2 GdNi compound have been investigated using magnetic measurements in the temperature range 4.2–300 K and with magnetic fields of up to 9 T. Al 2 GdNi orders ferromagnetically at Tc = 36.7 K with a magnetic moment of 7.25 μB/ f.u. , obtained from the spontaneous magnetization extrapolated to 0 K. The magnetic susceptibility obeys the Curie–Weiss law with μ eff = 8.6 μB/ f.u. and θp = 26.8 K . The results are discussed in terms of the Ruderman–Kittel–Kasuya–Yosida theory, the polarization of 5d electrons by the local exchange interaction 4f-5d and the spin fluctuations on Ni sites.
PHONONIC APPROACH TO FERROMAGNETIC SEMICONDUCTORS
Authors: KOO JE HUAN , CHO GUANGSUP
Published: April 2006

We investigated theoretically ferromagnetic semiconductors. We obtained the Curie temperature Tc for carriers of the one-band and two-band types using a modified Kondo lattice model for paramagnetic to ferromagnetic transition. We also acquired the electrical resistivity and optical conductivity from the basic principles. We calculated the magnetic field dependence of the resistivity in the presence of the external magnetic field, H. A relatively lower value of Tc in the case of ferromagnetic semiconductors in comparison with CMR manganites is elucidated.
STUDY OF HYSTERESIS BEHAVIOR OF CHARGES IN FLUORINATED POLYIMIDE FILM BY USING CAPACITANCE-VOLTAGE METHOD
Authors: LEE YONG K.
Published: April 2006

The hysteresis behavior of charges was observed in Capacitance-Voltage (C-V) curve characteristics of fluorinated polyimide film in MPS ( Cu -fluorinated polyimide film- Si ) test structure. The degree of hysteresis was almost constant up to 150°C and then sharply increased beyond 150°C. Hysteresis behavior up to 150°C was due to a fixed amount of mobile charges at the interface between fluorinated polyimide film and Si and one beyond 150°C was due to abrupt increase of mobile charges and their enhanced movement in the bulk of fluorinated polyimide film due to structural transition of fluorinated polyimide film.
MASTER-SLAVE SYNCHRONIZATION OF GENERAL LUR'E SYSTEMS WITH TIME-VARYING DELAY AND PARAMETER UNCERTAINTY
Authors: HUANG HE , LI HAN-XIONG , ZHONG JUE
Published: April 2006

This paper deals with the problem of master-slave synchronization for uncertain Lur'e systems via time-varying delay feedback control. The parametric uncertainty is assumed to be norm bounded. Several new and sufficient conditions are presented such that the uncertain Lur'e master and slave systems are synchronous for all admissible uncertainties. These synchronization criteria are dependent on the size of time delay, which can be expressed by means of matrix inequalities. The adopted method is based on defining a new Lyapunov–Krasovskii function and using some inequalities techniques. Our results obtained here extend and improve some previously related results. Finally, two numerical examples are provided to demonstrate the applications of our proposed results.
AN ALGEBRAIC STATE ESTIMATION APPROACH FOR THE RECOVERY OF CHAOTICALLY ENCRYPTED MESSAGES
Authors: SIRA-RAMÍREZ HEBERTT , FLIESS MICHEL
Published: April 2006

In this article, we use a variant of a recently introduced algebraic state estimation method obtained from a fast output signal time derivatives computation process. The fast time derivatives calculations are entirely based on the consequences of using the "algebraic approach" in linear systems description (basically, module theory and non-commutative algebra). Here, we demonstrate, through computer simulations, the effectiveness of the proposed algebraic approach in the accurate and fast (i.e. nonasymptotic) estimation of the chaotic states in some of the most popular chaotic systems. The proposed state estimation method can then be used in a coding–decoding process of a secret message transmission using the message-modulated chaotic system states and the reliable transmission of the chaotic system observable output. Simulation examples, using Chen's chaotic system and the Rossler system, demonstrate the important features of the proposed fast state estimation method in the accurate extraction of a chaotically encrypted messages. In our simulation results, the proposed approach is shown to be quite robust with respect to (computer generated) transmission noise perturbations. We also propose a way to evade computational singularities associated with the local lack of observability of certain chaotic system outputs and still carry out the encrypting and decoding of secret messages in a reliable manner.
FURTHER STUDIES ON NONLINEAR OSCILLATIONS AND CHAOS OF A SYMMETRIC CROSS-PLY LAMINATED THIN PLATE UNDER PARAMETRIC EXCITATION
Authors: ZHANG WEI , SONG CHUNZHI , YE MIN
Published: April 2006

In this paper, the nonlinear oscillations and chaotic dynamics of a parametrically excited simply supported symmetric cross-ply laminated composite rectangular thin plate are further investigated. Considering geometric nonlinearity and nonlinear damping, a two-degree-of-freedom nonlinear system under parametric excitation is obtained to give the nonlinear governing equations of motion for laminated composite plate subjected to in-plane load. The method of multiple scales is utilized to obtain the averaged equations that are numerically solved to obtain the steady bifurcation responses and analysis of stability for laminated composite thin plate. It is illustrated that under certain conditions laminated composite thin plate may have the multiple steady bifurcation solutions and jumping may occur. The chaotic motion of rectangular symmetric cross-ply laminated composite thin plate is also found by using numerical simulation. It is found that the occurrence of the periodic, quasi-periodic and chaotic motions for a parametrically excited four-edges simply supported rectangular symmetric cross-ply laminated composite thin plate depends on the parametric excitation.
DYNAMICS AND CODING OF A BIOLOGICALLY-MOTIVATED NETWORK
Authors: AGUIRRE CARLOS , MARTINS JOÃO , MENDES R. VILELA
Published: April 2006

A four-node network consisting of a negative circuit controlling a positive one is studied. It models some of the features of the p53 gene network. Using piecewise linear dynamics with thresholds, the allowed dynamical classes are fully characterized and coded. The biologically relevant situations are identified and conclusions drawn concerning the effectiveness of the p53 network as a tumor inhibitor mechanism.
STOCHASTIC CHAOS IN A NEURONAL MODEL
Authors: KOSMIDIS EFSTRATIOS K. , PAKDAMAN K.
Published: April 2006

Neuronal firing is one of the main information carriers in nervous systems. It has been reported that highly fluctuating, aperiodic "noise-like" inputs, similar to those occurring in areas of nervous systems, evoke reliable firing. To explain this surprising result it has been suggested that (i) the high frequency components of such inputs or a resonance phenomenon are responsible for reliable firing, with (ii) internal biophysical noise being the potential major inherent source of unreliability. Conversely, the present study shows that such fluctuating inputs do not always lead to reliability, even in the absence of noise. Using the noise-free FitzHugh–Nagumo model, we demonstrate a regime in which reliable firing never occurs. To analyze the changes responsible for unreliable firing we use methods from the Random Dynamical Systems theory. This is done through careful numerical investigations since no analytical solutions are known to our system. More precisely, from the observation that the stationary distributions remained qualitatively unchanged throughout the area of interest we conclude that the switch from reliable to unreliable firing is not associated to a phenomenological stochastic bifurcation. However, this change of behavior corresponded to a dynamical stochastic bifurcation, with the leading Lyapunov exponent of the system becoming positive. The bifurcation resulted also in a change of the stochastic attractor from a single stochastic equilibrium to one reminiscent of a strange attractor. The combination of these results lead us to argue that the unreliable firing results from stochastic chaos, and that such a phenomenon may limit the reliability of neurons in nervous systems.
FROM LOCAL ACTIVITY LEMMA BEYOND THE WAVE COMPUTATION REACTION–DIFFUSION CNN BASED NETWORKS
Authors: BUCOLO MAIDE , FORTUNA LUIGI , FRASCA MATTIA , GIUDICE SALVATORE
Published: April 2006

The Local Activity Lemma establishes that "A homogeneous nonconservative medium cannot exhibit complexity unless it is locally active". In this communication, starting from the previous remark we report examples that prove systems with complex local active behavior like Reaction–Diffusion Cellular Nonlinear Networks (RD-CNNs) can work as image processors also in the 3D domain.
STABILITY ANALYSIS OF DIFFERENTIAL EQUATIONS WITH TIME-DEPENDENT DELAY
Authors: DENG WEIHUA , WU YUJIANG , LI CHANGPIN
Published: April 2006

In this Letter, we study the stability of differential equations with time-dependent delay. Several theorems are established for stability on a finite time interval, called "interval stability" for simplicity, and Liapunov stability. These theorems are applied to the generalized Gauss-type predator–prey models, and satisfactory results are obtained.
SEVEN LARGE-AMPLITUDE LIMIT CYCLES IN A CUBIC POLYNOMIAL SYSTEM
Authors: LIU YIRONG , HUANG WENTAO
Published: April 2006

In this paper, the problem of limit cycles bifurcated from the equator for a cubic polynomial system is investigated. The best result so far in the literature for this problem is six limit cycles. By using the method of singular point value, we prove that a cubic polynomial system can bifurcate seven limit cycles from the equator. We also find that a rational system has an isochronous center at the equator.
AMPLITUDE CONTROL OF LIMIT CYCLE IN VAN DER POL SYSTEM
Authors: TANG JIASHI , CHEN ZILI
Published: April 2006

The feedback controllers are designed to modify the amplitude of limit cycles in van der Pol oscillator and generalized van der Pol oscillator. Bifurcation control equations of weakly nonlinear systems are obtained by using the method of multiple scales. Gain-amplitude curves of controlled systems are drawn. Based on numerical study, the brief results of controlling amplitude of limit cycle are given for strongly nonlinear system.
DECISION-LEVEL FUSION OF PCA AND LDA-BASED FACE RECOGNITION ALGORITHMS
Authors: MARCIALIS GIAN LUCA , ROLI FABIO
Published: April 2006

In this paper, a face recognition system based on the fusion of two well-known appearance-based algorithms, namely Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA), is proposed. Fusion is performed at the decision-level, that is, the outputs of the individual face recognition algorithms are combined. Two main benefits of such fusion are shown. First, the reduction of the dependence on the environmental conditions with respect to the best individual recognizer. Secondly, the overall performance improvement over the best individual recognizer. To this end, fusion is investigated under different environmental conditions, namely, "ideal" conditions, characterized by a very limited variability of environmental parameters, and "real" conditions with large variability of lighting and face expressions.
AUTOMATIC ACTIVE CONTOURS PROPAGATION IN A SEQUENCE OF MEDICAL IMAGES
Authors: DJEMAL KHALIFA , PUECH WILLIAM , ROSSETTO BRUNO
Published: April 2006

In this paper we present a new algorithm to track an organ in a sequence of medical images in order to achieve a 3D reconstruction. The automatic method that we propose allows the tracking of the external contour of the anatomical organ in all the sequence from one contour initialized by the user on the first image. The required operations for our tracking method are the region-based active contours segmentation. The objects localization with dynamic prediction of displacements is based on the level-set functions and the definition of the region of interest for the robust local estimation of the image model. An application of this method is the 3D reconstruction of abdominal aorta.
Mice Deficient in Biglycan and Fibromodulin as a Model for Temporomandibular Joint Osteoarthritis
Authors: Wadhwa Sunil , Embree Mildred , Ameye Laurent , Young Marian F.
Published: April 2006

The temporomandibular joint (TMJ) within the craniofacial complex is unique. In humans, the TMJ can become diseased resulting in severe and disabling pain. There are no cures for TMJ disease at this time. Animal models of TMJ disease are scarce, but some exist, and they are described in this paper. We present in greater detail one animal model that is deficient in two extracellular matrix (ECM) proteoglycans, biglycan (BGN) and fibromodulin (FMOD). Doubly deficient BGN/FMOD mice develop premature TMJ osteoarthritis (OA). In order to explore the mechanistic basis of TMJ-OA, tissues from the condyle of mutant mice were examined for their relative capacity to differentiate and undergo apoptosis. Our data show that there is a redistribution of the critical ECM protein, type II collagen, in mutant mice compared with controls. Mutant mice also have increased apoptosis of the chondrocytes embedded in the articular cartilage. We speculate that the overall imbalance in apoptosis may be the cellular basis for the abnormal production of structural ECM proteins. The abnormal production of the ECM could, in turn, lead to premature erosion and degradation of the articular surface resulting in TMJ-OA. These data underscore the importance of the ECM in controlling the structural integrity of the TMJ.
Hierarchies of Extracellular Matrix and Mineral Organization in Bone of the Craniofacial Complex and Skeleton
Authors: McKee M.D. , Addison W.N. , Kaartinen M.T.
Published: April 2006

Structural hierarchies are common in biologic systems and are particularly evident in biomineralized structures. In the craniofacial complex and skeleton of vertebrates, extracellular matrix and mineral of bone are structurally ordered at many dimensional scales from the macro level to the nano level. Indeed, the nanocomposite texture of bone, with nanocrystals of apatitic mineral embedded within a crosslinked matrix of fibrillar and nonfibrillar proteins, imparts to bone the very mechanical properties and toughness it needs to function in vital organ protection, musculoskeletal movement and mastication. This article focuses on how hierarchies of extracellular matrix protein organization influence bone cell behavior, tissue architecture and mineralization. Additional attention is given to recent work on the molecular determinants of mineral induction in bone, and how the mineralization process is subsequently regulated by inhibitory proteins.
Essential Roles of Ameloblastin in Maintaining Ameloblast Differentiation and Enamel Formation
Authors: Fukumoto Satoshi , Yamada Aya , Nonaka Kazuaki , Yamada Yoshihiko
Published: April 2006

During tooth development, dental epithelial cells interact with extracellular matrix components, such as the basement membrane and enamel matrix. Ameloblastin, an enamel matrix protein, plays a crucial role in maintaining the ameloblast differentiation state and is essential for enamel formation. Ameloblastin-null mice developed severe enamel hypoplasia. In mutant mice, dental epithelial cells started to differentiate into ameloblasts, but ameloblasts soon lost cell polarity, proliferated, and formed multiple cell layers, indicative of some aspects of preameloblast phenotypes. In addition, the expression of amelogenin, another component of the enamel matrix, was specifically reduced in mutant ameloblasts. More than 20% of amelobastin-null mice developed odontogenic tumors. We also found that recombinant ameloblastin specifically bound to ameloblasts and inhibited proliferation of dental epithelial cells. These results suggest that ameloblastin is an important regulator to maintain the differentiation state of ameloblasts.
Amelogenin Supra-Molecular Assembly in vitro Compared with the Architecture of the Forming Enamel Matrix
Authors: Moradian-Oldak Janet , Goldberg Michel
Published: April 2006

Tooth enamel is formed in the extracellular space within an organic matrix enriched in amelogenin proteins. Amelogenin nanosphere assembly is a key factor in controlling the oriented and organized growth of enamel apatite crystals. Recently, we have reported the formation of higher ordered structures resulting from organized association and self-orientation of amelogenin nanospheres in vitro. This remarkable hierarchical organization includes self-assembly of amelogenin molecules into subunits of 4–6 nm in diameter followed by their assembly to form nanospheres of 15–25 nm in radii. Chains of >100 nm length are then formed as the result of nanosphere association. These linear arrays of nanospheres assemble to form the microribbons that are hundreds of microns in length, tens of microns in width, and a few microns in thickness. Here, we review the step by step process of amelogenin self-assembly during the formation of microribbon structures in vitro. Assembly properties of selected amelogenins lacking the hydrophilic C terminus will then be reviewed. We will consider amelogenin as a template for the organized growth of crystals in vitro. Finally, we will compare the structures formed in vitro with globular and periodic structures observed earlier, in vivo, by different sample preparation conditions. We propose that the alignment of amelogenin nanospheres into long chains is evident in vivo, and is an important indication for the function of this protein in controlling the oriented and elongated growth of apatite crystals during enamel biomineralization.
Differential Regulation of Dentin Matrix Protein 1 Expression during Odontogenesis
Authors: Lu Yongbo , Zhang Shubin , Xie Yixia , Pi Yuli , Feng Jian Q.
Published: April 2006

Dentin matrix protein 1 (DMP1) is highly expressed in mineralized tooth and bone. Both in vitroand in vivodata show that DMP1 is critical for mineralization and tooth morphogenesis (growth and development). In this study, we studied Dmp1 gene regulation. The in vitrotransient transfection assay identified two important DNA fragments, the 2.4- and 9.6-kb promoter regions. We next generated and analyzed transgenic mice bearing the β-galactosidase (lacZ) reporter gene driven by the 2.4- or 9.6-kb promoter with the complete 4-kb intron 1. The 9.6-kb Dmp1-lacZ mice conferred a DMP1 expression pattern in odontoblasts identical to that in the endogenous Dmp1 gene. This is reflected by lacZ expression in Dmp1-lacZ knock-in mice during all stages of odontogenesis. In contrast, the 2.4-kb Dmp1-lacZ mice display activity in odontoblast cells only at the early stage of odontogenesis. Thus, we propose that different transcription factors regulate early or later cis-regulatory domains of the Dmp1 promoter, which gives rise to the unique spatial and temporal expression pattern of Dmp1 gene at different stages of tooth development.
New Definition of Small for Gestational Age Based on Fetal Growth Potential
Authors: Gardosi J.
Published: April 2006

Accurate definition of small for gestational age (SGA) is essential for antenatal as well as postnatal care. SGA is associated with significant antenatal and postnatal pathology. The term, however, includes constitutional smallness, and it is essential to adjust for physiological variation in order to identify those babies who are pathologically small. Maternal height, weight, parity, ethnic origin and the baby’s gender have all been found to be significantly associated with normal variation in birth weight. These variables need to be adjusted for to calculate the true growth potential, which can be represented as individually customized fetal growth curves and birth weight percentiles (www.gestation.net). This method for calculating growth potential has been validated in a number of international studies. ‘Customized SGA’ defines neonates with intrauterine growth restriction, while ‘small-normal’ does not represent increased risk. Currently, coefficients are being developed for more ethnic groups, to broaden the international applicability of individualized standards. Work is also underway to incorporate the customized birth weight percentile as the starting point of infant growth curves.
Normal and Abnormal Fetal Growth
Authors: Bryan S.M. , Hindmarsh P.C.
Published: April 2006

The fetal origins of adult disease hypothesis suggests that poor intrauterine growth is associated with an increased risk of cardiovascular disease. The hypothesis goes on to implicate different growth ‘phenotypes’, particularly disproportionate growth, in the determination of the type of cardiovascular disease that develops. Analysis of the antenatal growth of a low-risk pregnancy population does not identify such growth phenotypes within the general population. Rather, intrauterine growth is characterized by poor predictability of subsequent size, suggesting that centile crossing is a common feature of intrauterine growth. Furthermore, there is a sexually dimorphic pattern to this growth that needs to be considered in further work to test the fetal origins hypothesis.
Genetic Variations and Normal Fetal Growth
Authors: Dunger D.B. , Petry C.J. , Ong K.K.
Published: April 2006

Size at birth is said to be a highly heritable trait, with an estimated 30–70% of the variability a result of genetics. Data from family studies may be confounded, however, by potential interactions between fetal genes and the maternal uterine environment. Overall, the maternal environment tends to restrain fetal growth, and this is most evident in first pregnancies. Restraint of fetal growth appears to be inherited through the maternal line. Potential genetic candidates include the mitochondrial DNA 16189 variant, and common variants of exclusively maternally expressed genes, such as H19, which have been associated with size at birth. Maternal blood glucose levels and blood pressure are also correlated with size at birth, but the degree to which these changes relate to genetic variation in the mother is unclear. Elegant studies in mouse knockout models and rare genetic variants in humans have highlighted the importance of insulin-like growth factor I (IGF-I), IGF-II, insulin and their respective receptors in determining fetal growth. However, data linking common variation in the genes that regulate these proteins and receptors with size at birth are few and inconsistent. Interestingly, common variation in the insulin gene (INS) variable number tandem repeats, which regulates the transcription of insulin and IGF-II, has been associated with size at birth, largely in second and subsequent pregnancies, where maternal restraint is least evident. This suggests that fetal genes, and in particular paternally expressed genes, may have significant effects on fetal growth during pregnancies where maternal restraint of fetal growth is less evident.
Regulation of Maternal Metabolism by Pituitary and Placental Hormones: Roles in Fetal Development and Metabolic Programming
Authors: Freemark M.
Published: April 2006

This review outlines the regulation of maternal metabolism by hormones, cytokines and growth factors, highlighting recent studies that implicate disordered somatolactogen signalling in the pathogenesis of perinatal growth failure and the development of the metabolic syndrome.
Imprinted Genes, Placental Development and Fetal Growth
Authors: Fowden A.L. , Sibley C. , Reik W. , Constancia M.
Published: April 2006

In mammals, imprinted genes have an important role in feto-placental development. They affect the growth, morphology and nutrient transfer capacity of the placenta and, thereby, control the nutrient supply for fetal growth. In particular, the reciprocally imprinted Igf2–H19 gene complex has a central role in these processes and matches the placental nutrient supply to the fetal nutrient demands for growth. Comparison of Igf2P0 and complete Igf2 null mice has shown that interplay between placental and fetal Igf2 regulates both placental growth and nutrient transporter abundance. In turn, epigenetic modification of imprinted genes via changes in DNA methylation may provide a mechanism linking environmental cues to placental phenotype, with consequences for development both before and after birth. Changes in expression of imprinted genes, therefore, have major implications for developmental programming and may explain the poor prognosis of the infant born small for gestational age and the wide spectrum of adult-onset diseases that originate in utero.