bluuebunny/crossref_metadata_2025 huggingface dataset:
UVB‐lnduced DNA Damage and Its Photorepair in Nuclei and Chloroplasts of Spinacia oleracea L.
Authors: Hada M. , Hashimoto T. , Nikaido O. , Shin M.
Published: January 2008

Ultraviolet‐B‐induced lesions and their photorepair in nuclear and chloroplast DNA of spinach (Spinacia oleracea L.) leaves were examined with two photoproducts, cyclobutane pyrimidine dimers (CPD) and pyrimidine (6‐4) pyrimidinone photoproducts (6‐4PP). These photoproducts were induced both in nuclear and chloroplast DNA by UVB irradiation and could be detected by enzyme‐linked immunosorbent assay using their respective monoclonal antibodies. Formation of CPD was greater in nuclear DNA than in chloroplast DNA (about 10 to 7), whereas 6‐4PP formation was comparable in both DNA. On subsequent exposure of leaves to blue/UVA after UVB irradiation, photorepair of CPD and 6‐4PP occurred in nuclear DNA but not in chloroplast DNA. When isolated chloroplasts were irradiated with UVB, CPD was also induced in their DNA. But photorepair of CPD did not occur in them by subsequent exposure to blue/UVA, suggesting that no photorepair system operates in chloroplasts.
A Study of the Uptake of Toluidine Blue O by Porphyromonas gingivalis and the Mechanism of Lethal Photosensitization
Authors: Bhatti Manpreet , MacRobert Alexander , Meghji Sajeda , Henderson Brian , Wilson Michael
Published: January 2008

The purpose of the study was to determine the distribution of the photosensitizer toluidine blue O (TBO) within Porphyromonas gingivalis and the possible mechanism(s) involved in the lethal photosensitization of this organism. The distribution of TBO was determined by incubating P. gingivalis with tritiated TBO (3H‐TBO) and fractionating the cells into outer membrane (OM), plasma membrane (PM), cytoplasmic proteins, other cytoplasmic constituents and DNA. The percentage of TBO in each of the fractions was found to be, 86.7, 5.4, 1.9, 5.7 and 0.3%, respectively. The involvement of cytotoxic species in the lethal photosensitization induced by light from a helium‐neon (HeNe) laser and TBO was investigated by using deuterium oxide (D2O), which prolongs the lifetime of singlet oxygen, and the free radical and singlet oxygen scavenger L‐tryptophan. There were 9.0 log10 and 2 log10 reductions in the presence of D2O and H2O (saline solutions), respectively, at a light dose of 0.44 J (energy density = 0.22 J/cm2), suggesting the involvement of singlet oxygen. Decreased kills were attained in the presence of increasing concentrations of L‐tryptophan. The effect of lethal photosensitization on whole cell proteins was determined by measuring tryptophan fluorescence, which decreased by 30% using 4.3 J (energy density = 4.3 J/ cm2) of light. Effects on the OM and PM proteins were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. There was evidence of change in the molecular masses of several PM proteins and OM proteins compared to controls. There was evidence of damage to the DNA obtained from irradiated cells. Scanning electron microscopic studies showed that there was coaggre‐gation of P. gingivalis cells when sensitized and then exposed to laser light. These results suggest that lethal photosensitization of P. gingivalis may involve changes in OM and/or PM proteins and DNA damage mediated by singlet oxygen.
Treatment of Malignant Melanoma by High‐Peak‐Power 1064 nm Irradiation Followed by Photodynamic Therapy
Authors: Busetti Alessandra , Soncin Marina , Jori Giulio , Kenney Malcolm E. , Rodgers Michael A. J.
Published: January 2008

Irradiation of B16 pigmented melanoma subcutaneously transplanted in C57 mice with a single 650 mj pulse (10 ns) of 1064 nm light from a Q‐switched Nd: YAG laser caused instantaneous bleaching of the pigmented tissue. Visual and histological examination of the resulting gray‐colored tumor revealed the breakdown of melanosomes with no detectable alteration of the normal and tumor‐overlying skin. Histological examination of the irradiated tumor showed some degree of vascular damage; the depth of the photodamage was not affected by the successive delivery of three consecutive light pulses. The bleached tumor grew at a modestly slower rate but the high‐peak‐power (HPP) laser treatment did not affect the tumor concentration of a photodynamic sensitizer Si(IV)‐naphthalocyanine (isoBO‐SiNc) intravenously injected 24 h before Nd : YAG irradiation. Treatment of the B16 pigmented melanoma by photodynamic therapy (PDT: 1 mg/kg isoBO‐SiNc, 300 mW/cm2, 520 J/cm2) from a 774 nm diode laser immediately after the 1064 nm irradiation resulted in a 16 day delay of tumor regrowth, which was markedly longer than the delay (ca 6 days) obtained after PDT under identical conditions without the preirradia‐tion. Thus, pretreatment of pigmented tumors with HPP 1064 nm light appears to enhance their susceptibility to conventional PDT. The tumor response was further enhanced by repeating the combined HPP/PDT treatment at an interval of 10 days (regrowth delay: 27 days), as well as by applying hyperthermia immediately after HPP/PDT (regrowth delay: ca 34 days).
Comparison of the In Vivo Photodynamic Threshold Dose for Photofrin, Mono‐ and Tetrasulfonated Aluminum Phthalocyanine Using a Rat Liver Model
Authors: Farrell Thomas J. , Wilson Brian C. , Patterson Michael S. , Olivo Malini C.
Published: January 2008

The photodynamic threshold dose in normal rat liver was determined from the measured depth of necrosis following surface irradiation. The threshold was determined for the photosensitizing drugs Photofrin and monosulfo‐nated aluminum chlorophthalocyanine, AIPcS1, at 24 h postinjection and was found to be (3.4 ×/÷ 1.3) × 1018 (8.2 ×/÷ 1.5) × 1018photons cm‐3, respectively, compared with the previously reported value of (38 ± 2) × 1018photons cm‐3for the tri/tetrasulfonated phthalocyanine, AlPcS4. These values were independent of drug concentration or total light fluence. For all three drugs the depth of tissue necrosis decreased as the time between drug and light administration increased from 10 min to 72 h. This decrease can be attributed both to the change in the tissue drug concentration as well as to changes in the efficiency of photodynamic therapy for producing tissue damage, related to the photodynamic necrosis threshold. 1'he threshold values for all three photosensitizers were lowest at 10 min post injection: (1.4 ×/÷ 1.4) × 1018, (1.6 ×/÷ 1.3) × 1018 (23 ×/÷ 1.3) × 1018photons cm‐3for Photofrin, AIPcS1 and AlPcS4, respectively. The changes in necrosis threshold with time may be due to an initial change from entirely vascular to a combination of vascular and cellular damage, with later redistribution of the photosensiti/.er to targets at the subcellular level.
Characterization of Photoreceptor and Signaling Pathway for Light Induction of the Chlamydomonas Heat‐Shock Gene HSP70A
Authors: Kropat Janette , Beck Christoph F.
Published: January 2008

Light induces heat‐shock gene HSP70A by a heat stress‐independent pathway. Analysis of mutants defective in plastid‐localized chlorophyll synthesis as well as feeding of chlorophyll precursors have previously provided evidence for the participation of the chloroplast in this light induction. An involvement of photosynthesis appears unlikely because an inhibitor of photosystem II and various mutations causing defects in photosystems I and II or the cytb6/f complex did not affect light inducibility. The competence of a mutant defective in carotenoid biosynthesis for induction of HSP70A by light also ruled out the involvement of photoreceptors with a carotenoid‐based chromophore like chlamyrhodopsin. Analysis of the wavelength dependence of HSP70A mRNA accumulation revealed a major peak around 600 nm and a minor one around 450 nm. This suggests that a novel photoreceptor mediates this induction. Continuous irradiation during the induction phase was required for a sustained accumulation of HSP70A mRNA, indicating that continuous triggering of the signaling pathway is needed. A prerequisite for this light induction is a state of competence achieved by incubation of the cells in the dark for at least 1h.
Development of a Fiber Optic Probe to Measure NIR Raman Spectra of Cervical Tissue In Vivo
Authors: Mahadevan‐Jansen Anita , Mitchell Michele Follen , Ramanujam Nirmala , Utzinger Urs , Richards‐Kortum Rebecca
Published: January 2008

The goal of this study was to develop a compact fiber optic probe to measure near infrared Raman spectra of human cervical tissue in vivo for the clinical diagnosis of cervical precancers. A Raman spectrometer and fiber optic probe were designed, constructed and tested. The probe was first tested using standards with known Raman spectra, and then the probe was used to acquire Raman spectra from normal and precancerous cervical tissue in vivo. Raman spectra of cervical tissue could be acquired in vivo in 90 s using incident powers comparable to the threshold limit values for laser exposure of the skin. Although some silica signal obscured tissue Raman bands below 900 cm‐1, Raman features from cervical tissue could clearly be discerned with an acceptable signal‐to‐noise ratio above 900 cm‐1. The success of the Raman probe described here indicates that near infrared Raman spectra can be measured in vivo from cervical tissues. Increasing the power of the excitation source could reduce the integration time to below 20 s.
Comparison of the Antimicrobial Effects of Chlorine, Silver Ion, and Tobramycin on Biofilm
Authors: Kim Jaeeun , Pitts Betsey , Stewart Philip S. , Camper Anne , Yoon Jeyong
Published: January 2008

The systematic understanding of how various antimicrobial agents are involved in controlling biofilms is essential in order to establish an effective strategy for biofilm control, since many antimicrobial agents are effective against planktonic cells but are ineffective when they are used against the same bacteria growing in a biofilm state. Three different antimicrobial agents (chlorine, silver, and tobramycin) and three different methods for the measurement of membrane integrity (plate counts, the measurement of respiratory activity with 5-cyano-2,3-ditolyl tetrazolium chloride [CTC] staining, and BacLight Live/Dead staining) were used along with confocal laser scanning microscopy (CLSM) and epifluorescence microscopy to examine the activities of the antimicrobials on biofilms in a comparative way. The three methods of determining the activities of the antimicrobials gave very different results for each antimicrobial agent. Among the three antimicrobials, tobramycin appeared to be the most effective in reducing the respiratory activity of biofilm cells, based upon CTC staining. In contrast, tobramycin-treated biofilm cells maintained their membrane integrity better than chlorine- or silver-treated ones, as evidenced by imaging by both CLSM and epifluorescence microscopy. Combined and sequential treatments with silver and tobramycin showed an enhanced antimicrobial efficiency of more than 200%, while the antimicrobial activity of either chlorine or tobramycin was antagonized when the agents were used in combination. This observation makes sense when the different oxidative reactivities of chlorine, silver, and tobramycin are considered.
gp63 in Stable Cationic Liposomes Confers Sustained Vaccine Immunity to Susceptible BALB/c Mice Infected withLeishmania donovani
Authors: Bhowmick Swati , Ravindran Rajesh , Ali Nahid
Published: January 2008

Visceral leishmaniasis is deadly if not treated, and development of a vaccine with long-term immunity remains a challenge. In this study, we showed that cationic distearoyl phosphatidylcholine (DSPC) liposomes, when used as vaccine adjuvant with the immunodominant 63-kDa glycoprotein (gp63) ofLeishmania donovanipromastigotes, induced significant protection against progressive visceral leishmaniasis in susceptible BALB/c mice. gp63 used without adjuvant elicited partial protection but in association with liposomes exhibited marked resistance in both the livers and spleens of the mice challenged 10 days after the last vaccination. The protective efficacy of liposomal gp63 vaccination was dose dependent, with 2.5 μg of protein showing optimal protection. The immunity conferred by this vaccine formulation was durable, as mice challenged 12 weeks after immunization were still protected, and the infection was controlled for at least 3 months postchallenge. Production of gamma interferon (IFN-γ) and interleukin-4 (IL-4) by splenic T cells, and of serum immunoglobulin G1 (IgG1) and IgG2a following immunization, suggested that a mixed Th1/Th2 response had been induced following immunization. However, control of disease progression and parasitic burden in mice vaccinated with gp63 in cationic DSPC liposomes was associated with enhancement of antigen-specific IFN-γ and downregulation of IL-4, demonstrating a Th1 bias. Long-term immunity elicited by this vaccine corresponded to, in addition to the presence of antigen-specific Th1, CD8+T-cell responses. Our results demonstrated that stable cationic liposomes containing gp63 acted as a potent adjuvant for protein antigen to induce long-term protection againstL. donovanithat represents an alternative to DNA vaccination.
The Acute-Phase Reactant C-Reactive Protein Binds to Phosphorylcholine-ExpressingNeisseria meningitidisand Increases Uptake by Human Phagocytes
Authors: Casey Rosalyn , Newcombe Jane , McFadden JohnJoe , Bodman-Smith Katherine B.
Published: January 2008

Neisseria meningitidisis a global cause of meningitis and septicemia. Immunity toN. meningitidisinvolves both innate and specific mechanisms with killing by serum bactericidal activity and phagocytic cells. C-reactive protein (CRP) is an acute-phase serum protein that has been shown to help protect the host from several bacterial pathogens, which it recognizes by binding to phosphorylcholine (PC) on their surfaces. PathogenicNeisseriaspecies can exhibit phase-variable PC modification on type 1 and 2 pili. We have shown that CRP can bind to piliated meningococci in a classical calcium-dependent manner. The binding of CRP to the meningococcus was concentration dependent, of low affinity, and specific for PC. CRP appears to act as an opsonin forN. meningitidis, as CRP-opsonized bacteria showed increased uptake by human macrophages and neutrophils. Further investigation into the downstream effects of CRP-boundN. meningitidismay lead us to a better understanding of meningococcal infection and help direct more effective therapeutic interventions.
Coinfection withHeligmosomoides polygyrusFails To Establish CD8+T-Cell Immunity againstToxoplasma gondii
Authors: Khan Imtiaz A. , Hakak Rubeena , Eberle Karen , Sayles Peter , Weiss Louis M. , Urban Joseph F.
Published: January 2008

CD8+T-cell immunity is important for long-term protection againstToxoplasma gondiiinfection. However, a Th1 cytokine environment, especially the presence of gamma interferon (IFN-γ), is essential for the development of primary CD8+T-cell immunity against this obligate intracellular pathogen. Earlier studies from our laboratory have demonstrated that mice lacking optimal IFN-γ levels fail to develop robust CD8+T-cell immunity againstT. gondii. In the present study, induction of primary CD8+T-cell immune response againstT. gondiiinfection was evaluated in mice infected earlier withHeligmosomoides polygyrus, a gastrointestinal worm known to evoke a polarized Th2 response in the host. In the early stage ofT. gondiiinfection, both CD4 and CD8+T-cell responses against the parasite were suppressed in the dually infected mice. At the later stages, however,T. gondii-specific CD4+T-cell immunity recovered, while CD8+T-cell responses remained low. Unlike in mice infected withT. gondiialone, depletion of CD4+T cells in the dually infected mice led to reactivation of chronic infection, leading toToxoplasma-related encephalitis. Our observations strongly suggest that prior infection with a Th2 cytokine-polarizing pathogen can inhibit the development of CD8+T-cell immune response againstT. gondii, thus compromising long-term protection against a protozoan parasite. This is the first study to examine the generation of CD8+T-cell immune response in a parasitic nematode and protozoan coinfection model that has important implications for infections where a CD8+T-cell response is critical for host protection and reduced infection pathology.
Aggregation via the Red, Dry, and Rough Morphotype Is Not a Virulence Adaptation in
Salmonella enterica
Serovar Typhimurium
Authors: White A. P. , Gibson D. L. , Grassl G. A. , Kay W. W. , Finlay B. B. , Vallance B. A. , Surette M. G.
Published: January 2008

The
Salmonella
rdar (
r
ed,
d
ry,
a
nd
r
ough) morphotype is an aggregative and resistant physiology that has been linked to survival in nutrient-limited environments. Growth of
Salmonella enterica
serovar Typhimurium was analyzed in a variety of nutrient-limiting conditions to determine whether aggregation would occur at low cell densities and whether the rdar morphotype was involved in this process. The resulting cultures consisted of two populations of cells, aggregated and nonaggregated, with the aggregated cells preferentially displaying rdar morphotype gene expression. The two groups of cells could be separated based on the principle that aggregated cells were producing greater amounts of thin aggregative fimbriae (Tafi or curli). In addition, the aggregated cells retained some physiological characteristics of the rdar morphotype, such as increased resistance to sodium hypochlorite. Competitive infection experiments in mice showed that nonaggregative Δ
agfA
cells outcompeted rdar-positive wild-type cells in all tissues analyzed, indicating that aggregation via the rdar morphotype was not a virulence adaptation in
Salmonella enterica
serovar Typhimurium. Furthermore, in vivo imaging experiments showed that Tafi genes were not expressed during infection but were expressed once
Salmonella
was passed out of the mice into the feces. We hypothesize that the primary role of the rdar morphotype is to enhance
Salmonella
survival outside the host, thereby aiding in transmission.
Comparative Genomic Analysis Using Microarray Demonstrates a Strong Correlation between the Presence of the 80-Kilobase Pathogenicity Island and Pathogenicity in Kanagawa Phenomenon-Positive
Vibrio parahaemolyticus
Strains
Authors: Izutsu Kaori , Kurokawa Ken , Tashiro Kosuke , Kuhara Satoru , Hayashi Tetsuya , Honda Takeshi , Iida Tetsuya
Published: January 2008

Vibrio parahaemolyticus
is a gram-negative marine bacterium. A limited population of the organisms causes acute gastroenteritis in humans. Almost all of the clinical
V. parahaemolyticus
isolates exhibit beta-type hemolysis on Wagatsuma agar, known as the Kanagawa phenomenon (KP). KP is induced by the thermostable direct hemolysin produced by the organism and has been considered a crucial marker to distinguish pathogenic strains from nonpathogenic ones. Since 1996, so-called “pandemic clones,” the majority of which belong to serotype O3:K6, have caused worldwide outbreaks of gastroenteritis. In this study, we used a DNA microarray constructed based on the genome sequence of a pandemic
V. parahaemolyticus
strain, RIMD2210633, to examine the genomic composition of 22 strains of
V. parahaemolyticus
, including both pathogenic (pandemic and nonpandemic) and nonpathogenic strains. More than 86% of the RIMD2210633 genes were conserved in all of the strains tested. Many variably present genes formed gene clusters on the genome of RIMD2210633 and were probably acquired through lateral gene transfer. At least 65 genes over 11 loci were specifically present in the pandemic strains compared with any of the nonpandemic strains, suggesting that the difference between pandemic and nonpandemic strains is not due to a simple genetic event. Only the genes in the 80-kb pathogenicity island (Vp-PAI) on chromosome II, including two
tdh
genes and a set of genes for the type III secretion system, were detected only in the KP-positive pathogenic strains. These results strongly suggest that acquisition of this Vp-PAI was crucial for the emergence of
V. parahaemolyticus
strains that are pathogenic for humans.
LATTICE BOLTZMANN APPROACH TO HIGH-SPEED COMPRESSIBLE FLOWS
Authors: PAN X. F. , XU AIGUO , ZHANG GUANGCAI , JIANG SONG
Published: January 2008

We present an improved lattice Boltzmann model for high-speed compressible flows. The model is composed of a discrete-velocity model by Kataoka and Tsutahara15 and an appropriate finite-difference scheme combined with an additional dissipation term. With the dissipation term parameters in the model can be flexibly chosen so that the von Neumann stability condition is satisfied. The influence of the various model parameters on the numerical stability is analyzed and some reference values of parameter are suggested. The new scheme works for both subsonic and supersonic flows with a Mach number up to 30 (or higher), which is validated by well-known benchmark tests. Simulations on Riemann problems with very high ratios (1000:1) of pressure and density also show good accuracy and stability. Successful recovering of regular and double Mach shock reflections shows the potential application of the lattice Boltzmann model to fluid systems where non-equilibrium processes are intrinsic. The new scheme for stability can be easily extended to other lattice Boltzmann models.
CLUSTERIZATION, FRUSTRATION AND COLLECTIVITY IN RANDOM NETWORKS
Authors: MAŃKA ANNA , MALARZ KRZYSZTOF , KUŁAKOWSKI KRZYSZTOF
Published: January 2008

We consider the random Erdös–Rényi network with enhanced clusterization and Ising spins s = ±1 at the network nodes. Mutually linked spins interact with energy J. Magnetic properties of the system that are dependent on the clustering coefficient C are investigated with the Monte Carlo heat bath algorithm. For J > 0 the Curie temperature Tcincreases from 3.9 to 5.5 when C increases from almost zero to 0.18. These results deviate only slightly from the mean field theory. For J < 0 the spin-glass phase appears below TSG; this temperature decreases with C, on the contrary to the mean field calculations. The results are interpreted in terms of social systems.
DYNAMICS OF ROUTING MECHANISMS ON TRAFFIC NETWORKS
Authors: SUN H. J. , WU J. J. , GAO Z. Y.
Published: January 2008

In this paper, we propose a simple betweenness-driven model to capture the dynamics of traffic routing choice behaviors. By comparing with two other models (degree-driven and cost-driven), it is shown that the cost-driven routing strategy is more complex and sensitive to traffic congestion. Another result indicates that the load distributions are determined by the connectivity distribution and route choice behaviors of the traffic network. The model thus provides useful insight for the design of traffic networks.
EVALUATING THE NATURE OF CHEMICAL BONDS BASED ON PROBABILISTIC MODELS
Authors: MOHAJERI A. , DASMEH P.
Published: January 2008

A theoretical measure of the ionicity based on different mathematical concepts is presented in this research. Considering the distribution of valence electrons on each atom in a bond, we assume that the chemical properties of the atom can be expressed by means of probability. Using the introduced probability, different probabilistic models such as classical, fuzzy and information theoretical models have been employed to introduce new descriptors of bond ionicity. The ionicities were calculated for 12 heterodiatomic molecules and the bonds were classified in terms of covalency vs. ionicity. It was found that our proposed ionicity descriptors correlate well with the partial ionic character of the bonds.
NONLINEAR METHODS OF CARDIOVASCULAR PHYSICS AND THEIR CLINICAL APPLICABILITY
Authors: WESSEL NIELS , MALBERG HAGEN , BAUERNSCHMITT ROBERT , KURTHS JÜRGEN
Published: January 2008

In this tutorial we present recently developed nonlinear methods of cardiovascular physics and show their potentials to clinically relevant problems in cardiology. The first part describes methods of cardiovascular physics, especially data analysis and modeling of noninvasively measured biosignals, with the aim to improve clinical diagnostics and to improve the understanding of cardiovascular regulation. Applications of nonlinear data analysis and modeling tools are various and outlined in the second part of this tutorial: monitoring-, diagnosis-, course and mortality prognoses as well as early detection of heart diseases. We show, that these data analyses and modeling methods lead to significant improvements in different medical fields.
WHEN SYMMETRIZATION GUARANTEES SYNCHRONIZATION IN DIRECTED NETWORKS
Authors: BELYKH IGOR , HASLER MARTIN , BELYKH VLADIMIR
Published: January 2008

We review and illustrate our recent results on globally stable synchronization in directed oscillator networks. We consider asymmetrically connected networks with node balance, the property that the sum of the coupling coefficients of all edges directed to a node equals the sum of the coupling coefficients of all the edges directed outward from the node. We show that for such directed but node balanced networks, it is sufficient to symmetrize all connections by replacing a unidirectional coupling with a bidirectional coupling of half the coupling strength. The synchronization condition for the symmetrized network then guarantees synchronization in the original directed network. By considering an example of coupled driven pendula, we show how to prove global stability of synchronization in a concrete unidirectional network. We also discuss the relation between local and global synchronization.
NEOCORTEX'S SMALL WORLD OF FRACTAL COUPLING
Authors: WAGNER C. , STOOP R.
Published: January 2008

Biological neocortical neurons are arranged in a columnar clustered architecture. Using a mathematical model in which the clustering properties can be monitored by means of a connectivity probability function, we investigate the information propagation in the associated networks, by means of simulations and a semi-analytical approach. Our analysis demonstrates that for systems with n-nearest neighbor coupling, the information propagation increases linearly in the neighbor order n. For fractal coupling, shown to give rise to small-world network characteristics, in contrast, an enhanced dependence is found, that, in our model of the neocortex, quickly saturates at a high level, indicating the superiority of this network type.
TOWARDS THRESHOLD FREQUENCY IN CHAOTIC COLPITTS OSCILLATOR
Authors: LINDBERG ERIK , TAMAŠEVIČIUS ARŪNAS , MYKOLAITIS GYTIS , BUMELIENĖ SKAIDRA
Published: January 2008

A novel version of chaotic Colpitts oscillator is described. Instead of a linear loss resistor, it includes an extra inductor and a diode in the collector circuit of the transistor. The modified circuit in comparison with the common Colpitts oscillator may generate chaotic oscillations at the fundamental frequency f* noticeably closer to the threshold frequency fT of the employed bipolar junction transistor, up to f* ≈ 0.6fT.
RECURRENCE QUANTIFICATION ANALYSIS: INTRODUCTION AND HISTORICAL CONTEXT
Authors: ZBILUT JOSEPH P. , WEBBER CHARLES L.
Published: January 2008

Although chaotic systems continue to gain interest, their confirmation and analysis can be difficult. Traditional analytic methods impose constraints which are often difficult to achieve. A technique which does not impose these constraints is recurrence quantification analysis. Recurrence quantification is derived from recurrence plots, which are based upon distances matrices of embedded series. The original article demonstrated the plot's ability to uncover deterministic processes, as well as drift and nonstationarity. Recurrence quantification has allowed for direct quantification of these features.
EFFECTS OF DEGREE CORRELATION ON THE SYNCHRONIZATION OF NETWORKS OF OSCILLATORS
Authors: DI BERNARDO M. , GAROFALO F. , SORRENTINO F.
Published: January 2008

In this paper, we investigate the effects of degree correlation on the synchronization of networks of coupled identical nonlinear oscillators. Firstly, it is shown both numerically and theoretically that synchronizability is enhanced when the network topology exhibits negative degree correlation. Then, the synchronization dynamics is studied of a network of identical Rössler oscillators under variation of the network degree correlation properties. We observe that negative correlation has a positive effect on the synchronization dynamics of such networks.
ONSET OF PHASE SYNCHRONIZATION IN NEURONS WITH CHEMICAL SYNAPSE
Authors: PEREIRA T. , BAPTISTA M. S. , KURTHS J. , REYES M. B.
Published: January 2008

We study the onset of synchronous states in realistic chaotic neurons coupled by mutually inhibitory chemical synapses. For the realistic parameters, namely the synaptic strength and the intrinsic current, this synapse introduces noncoherences in the neuronal dynamics, yet allowing for chaotic phase synchronization in a large range of parameters. As we increase the synaptic strength, the neurons reach a periodic state, and no chaotic complete synchronization is found.
CHAOS DOES HELP MOTION CONTROL
Authors: BUSCARINO ARTURO , FORTUNA LUIGI , FRASCA MATTIA , MUSCATO GIOVANNI
Published: January 2008

This work consists in the realization and control of a walking microrobot actuated by piezoelectric materials. Usually, the actuation of robot legs is controlled by square wave signals characterized by fixed amplitude and frequency. In this work the control signals are generated performing a frequency modulation driven by the chaotic evolution of Chua's circuit state variables. The smooth changes of the actuation signal frequency, performed by our chaotic system, enhance the microrobot walking capabilities especially when walking on given surfaces.
WHEN IS SHOOTING APPROPRIATE IN STEADY STATE ANALYSIS OF NONLINEAR CIRCUITS
Authors: CONSTANTINESCU FLORIN , NITESCU MIRUNA , IONESCU ANCA
Published: January 2008

An algorithm that can decide, prior to performing the circuit analysis, if a procedure for the fast computation of the periodic steady state is necessary, is presented in this paper. The analysis of a switching supply illustrates how this algorithm works.
STABILIZATION OF CHAOTIC BEHAVIOR IN THE RESTRICTED THREE-BODY PROBLEM
Authors: DZHANOEV ARSEN , LOSKUTOV ALEXANDER
Published: January 2008

The restricted three-body problem on the example of a perturbed Sitnikov case is considered. On the basis of the Melnikov method we study a possibility to stabilize the obtained chaotic solutions by two bodies placed in the triangular Lagrange points. It is shown that in this case, in addition to regular and chaotic solutions, there exist stabilized solutions.
CRYPTANALYSIS OF CHAOS-BASED ELGAMAL PUBLIC-KEY ENCRYPTION
Authors: HANE RYUICHI , KOHDA TOHRU
Published: January 2008

An ElGamal public-key cryptosystem based on Chebyshev maps has recently been proposed, where one can maximize the benefits of the property of Chebyshev polynomials of degree p, Tp(·), i.e. commutativity. However, we have to confront the following two disadvantages of commutativity in using such a real-valued chaotic cryptosystem: (1) Commutativity gives a set of public keys (xi, yi = Ts(xi)) for an integer i from a public key (x, y = Ts(x)) with a private key s. This set constitutes a pair of empirical distributions of (fX(x), fY(y) = PTs{fX(x)}), where PTs is the Perron-Frobenius operator of Ts(·). (2) The resonance property of Tp(·) enables us to take a statistical approach to find the private key s based on prime factorization of integer.
SINGLE-ELECTRON CIRCUITS PERFORMING DENDRITIC PATTERN FORMATION WITH NATURE-INSPIRED CELLULAR AUTOMATA
Authors: OYA TAKAHIDE , MOTOIKE IKUKO N. , ASAI TETSUYA
Published: January 2008

We propose a novel semiconductor device in which electronic-analogue dendritic trees grow on multilayer single-electron circuits. A simple cellular-automaton circuit was designed for generating dendritic patterns by utilizing the physical properties of single-electron devices, i.e. quantum and thermal effects in tunneling junctions. We demonstrate typical operations of the proposed circuit through extensive numerical simulations.
SPLINE APPROXIMATION APPLICATION TO RECONSTRUCTION OF DISCRETE MAP FUNCTIONS
Authors: TOMASHEVSKAYA MARIA
Published: January 2008

The final goal of conducted research is to make a comparison of spline and polynomial approximation methods to reconstruct a priori unknown nonlinear map functions based on observed chaotic time series in the additive noise presence. Logistic and tent map functions are considered in detail as an example.
LEARNING AND RECALLING OF PHASE PATTERNS IN COUPLED BVP OSCILLATORS WITH TIME DELAY
Authors: YAMAMOTO TETSUYA , AMEMIYA TAKASHI , YAMAGUCHI TOMOHIKO
Published: January 2008

We study a learning and recalling model of phase patterns in a two- or three-coupled BVP oscillators system with a time delay δ. The coupling strengths are modulated by the Hebbian learning rule. Assuming the first-order approximation, we calculate the optimal condition of δ for exact recall by applying the phase dynamics theory. When α = 0, where α represents the coupling from activator to inhibitor, the correlation between the learning and the retrieval phase depends on δ. When α = 1, exact recall is achieved independent of δ. The results can be explained by the phase dynamics theory.
TEMPORARY DIMENSIONS OF MULTIVARIATE DATA FROM PALEOCLIMATE RECORDS — A NOVEL MEASURE FOR DYNAMIC CHARACTERIZATION OF LONG-TERM CLIMATE CHANGE
Authors: DONNER REIK , WITT ANNETTE
Published: January 2008

Standard techniques of nonlinear data analysis are difficult to apply to short or insufficiently resolved multivariate time series. We demonstrate that dimension estimation based on the decay of eigenvalues of the covariance matrix yields qualitatively robust characteristics even in the case of very short measurement series. The uncertainty of these characteristics is discussed for both: synthetic data sets and measurement data. We apply this approach to measurements of trace element abundances in a marine sediment core obtained at the East Antarctic coast and discuss the results from a paleoclimate point of view.
SOME DESIGN RULES FOR CHAOS-BASED ENCRYPTION SYSTEMS
Authors: KELBER KRISTINA , SCHWARZ WOLFGANG
Published: January 2008

During the past decade a large number of chaos-based encryption systems have been suggested and investigated. Cryptographical analysis of these systems shows that some of them are cryptographically weak. In this paper, some general design rules for chaos-based encryption systems are derived based on strengths and weaknesses of already suggested systems.
Research on the Correlation Among Critical Success Factors, of Knowledge Management, Executive Degree of Knowledge Management Activities and New Product Development Performance in Taiwan's High-Tech Firms
Authors: Chung Yi-Chan , Tsai Chih-Hung , Hsu Yau-Wen
Published: January 2008

Knowledge Management (KM) is an important issue in the 21st century and its execution has become a necessary process for enterprises to reach a level of sustainable development. Enterprises should value their own KM activities and accomplish the goal of sustainable operation through the promotion of effective KM activities. This research studies the impact of the critical success factors of KM on the implementation of KM activities, and its impact on new product development performance. The two intermediate variables, industry groups and the enterprise scales, are considered. After reviewing the literature, this research developed a theoretical model of the factors influencing these relationships. The research results found that the executive degree of critical KM success factors (five dimensions) revealed a significant influence on the executive degree of KM activities. The executive degree of KM activities also revealed a significant impact on new product development performance. As to the intermediate variables of industry groups and enterprise scales, this research proved that industry groups and the enterprise scales do not have any significant influence on the executive degree of KM activities or the new product development performance.
DETECTING HUMAN ABNORMAL BEHAVIORS IN CROWD
Authors: ZHONG ZHI , YE WEIZHONG , XU YANGSHENG
Published: January 2008

Detecting human abnormal behaviors in a crowded situation is a challenging problem for public security departments. Human abnormal behaviors are seen either in an individual or in a crowd. This paper is focused on the latter, which is more crucial at some important spots and has been less studied. To achieve this goal, we define two categories of video energy based on intensity variation and motion features and adopt two surveillance methods for the two energy accordingly. Using wavelet analysis of the energy curves, we have obtained a result which shows that both methods can be used to deal with crowd modeling and real-time surveillance satisfactorily. A comparison of the two methods is then made in the actual environment in a metro surveillance system.
Grenville-age pseudotachylite in the Lewisian: laserprobe
40
Ar/
39
Ar ages from the Gairloch region of Scotland (UK)
Authors: Sherlock Sarah C. , Jones Kevin A. , Park R.Graham
Published: January 2008

Infrared laserprobe
40
Ar/
39
Ar dating has been used to date pseudotachylite and host-rock minerals from a crush belt in the Lewisian basement of Scotland. It has revealed complexity in the pseudotachylite data that is attributable to the presence of refractory host-rock clasts and mineral fragments in the pseudotachylite. In conjunction with the host-rock mineral laserprobe
40
Ar/
39
Ar data it has been possible to simplify the pseudotachylite data for the samples, and the preferred ages for these are: 980 ± 39 Ma, 999 ± 31 Ma and 1024 ± 30 Ma (2σ). These ages are the first record of Grenville-aged brittle deformation in the Lewisian. Further, this study serves to illustrate the complexity of dating pseudotachylites, and the advantages and limitations of the IR laserprobe applied to such materials.
Stratigraphic imprint of the Late Palaeozoic Ice Age in eastern Australia: a record of alternating glacial and nonglacial climate regime
Authors: FIELDING CHRISTOPHER R. , FRANK TRACY D. , BIRGENHEIER LAUREN P. , RYGEL MICHAEL C. , JONES ANDREW T. , ROBERTS JOHN
Published: January 2008

Stratigraphic and sedimentological data from New South Wales and Queensland, eastern Australia, indicate that the Late Palaeozoic Ice Age comprised at least eight discrete glacial intervals (each 1–8 Ma in duration, here termed ‘glaciations’), separated by nonglacial intervals of comparable duration. These events spanned an interval from mid-Carboniferous (
c
. 327 Ma) to the early Late Permian (
c
. 260 Ma), and illustrate a pattern of increasing climatic austerity and increasingly widespread glacial ice from initial onset until an acme in the late Early Permian, followed by an opposite trend towards the final demise of glaciation in the Late Permian. The alternating glacial–nonglacial motif suggests that the Late Palaeozoic Ice Age was considerably more dynamic than previously thought. These patterns are remarkably consistent with recent interpretations of palaeofloral change, eustatic sea-level fluctuations and CO
2
–climate–glaciation relationships for this interval of time. The detailed record of alternating glacial and nonglacial climate mode disclosed herein may facilitate more closely resolved evaluations of stratigraphic records elsewhere, notably in far-field, ice-distal, northern hemisphere successions.
Detrital zircon U–Pb dating of low-grade metamorphic rocks in the Sulu UHP belt: evidence for overthrusting of the North China Craton onto the South China Craton during continental subduction
Authors: ZHOU JIAN-BO , WILDE SIMON A. , ZHAO GUO-CHUN , ZHENG CHANG-QING , JIN WEI , ZHANG Xing-ZHOU , CHENG HONG
Published: January 2008

The Shiqiao–Pingshang low-grade metasedimentary rocks sporadically crop out in the Sulu ultrahigh-pressure (UHP) belt in east–central China. Major and trace element data indicate that they were deposited in a passive margin basin, probably located at the southern margin of the North China Craton. Sensitive high-resolution ion microprobe (SHRIMP) U–Pb dating of detrital zircons from a quartzite (SD53) from Pingshang and a quartz schist (SD54) from Shiqiao records ages ranging from 2800 to 1900 Ma. Three age populations are defined: at 2660–2500, 2350–2150 and 2100–1900 Ma, with peak ages at 2522, 2212 and 2020 Ma, respectively. Muscovite Ar–Ar dating of the quartz schist (SD54) yields a plateau age of 265.9 ± 1.2 Ma. These data support the view that the Shiqiao–Pingshang low-grade metasedimentary rocks originated from the North China Craton, and underwent deformation in the Permian during subduction of the South China Craton (Yangtze block) beneath the North China Craton. This requires that the low-grade metasedimentary rocks were overthrust for several tens of kilometres onto the South China Craton, explaining why source materials from the North China Craton are common in Triassic to Jurassic sedimentary basins adjacent to the Dabie–Sulu orogenic belt.
Cretaceous dykes discovered in the Falkland Islands: implications for regional tectonics in the South Atlantic
Authors: STONE P. , RICHARDS P.C. , KIMBELL G.S. , ESSER R.P. , REEVES D.
Published: January 2008

New aeromagnetic data resolve the dykes of the Falkland Islands into three swarms. A hitherto unrecognized suite of north–south dykes is established as early Cretaceous by an Ar–Ar date of about 121 Ma. Swarms of NE–SW and east–west dykes are both early Jurassic: the former gives an Ar–Ar age of about 178 Ma, whereas the latter has been previously dated to about 190 Ma. The intrusion of the Cretaceous dykes marks the onset of oceanic crust generation in the South Atlantic and so restricts to mid-Jurassic the microplate rotation envisaged in most models for the Falklands break-out from Gondwana.
Cochlear Outer Hair Cell Motility
Authors: Ashmore Jonathan
Published: January 2008

Normal hearing depends on sound amplification within the mammalian cochlea. The amplification, without which the auditory system is effectively deaf, can be traced to the correct functioning of a group of motile sensory hair cells, the outer hair cells of the cochlea. Acting like motor cells, outer hair cells produce forces that are driven by graded changes in membrane potential. The forces depend on the presence of a motor protein in the lateral membrane of the cells. This protein, known as prestin, is a member of a transporter superfamily SLC26. The functional and structural properties of prestin are described in this review. Whether outer hair cell motility might account for sound amplification at all frequencies is also a critical question and is reviewed here.
Estimation of the Mortality Risk of Surgical Intensive Care Patients Based on Routine Laboratory Parameters
Authors: Stachon A. , Becker A. , Holland-Letz T. , Friese J. , Kempf R. , Krieg M.
Published: January 2008

Background: In established risk score models the collection and documentation of clinical data is time-consuming, causes labor-related costs, and is dependent on the examiner. Material and Methods: Based on low-cost laboratory parameters that are routinely measured at admission to the intensive care unit, a new score was developed (n = 271, study sample) and validated in an independent group of patients (n = 283, validation sample). Parameters were selected by a stepwise logistic regression analysis. This new score was compared to established risk models (APACHE II, SAPS II). Results: Mean age was 61.3 ± 1.2 years (study sample) and 63.1 ± 1.1 years (validation sample), respectively. In-hospital mortality was 24.7% (67/271, study sample) and 23.3% (66/283, validation sample). The following parameters were used to build the new score called Dense Laboratory Whole Blood Applied Risk Estimation (DELAWARE): alanine aminotransferase, C-reactive protein, cholesterol, creatine kinase MB, leukocytes, potassium, thrombocytes, triglycerides, and age. The areas under the curves were 0.853/0.813 (study sample/validation sample). In the study sample DELAWARE correlated with APACHE II (r = 0.586) and SAPS II (r = 0.614; p < 0.001), respectively. Conclusions: A general admission risk score for surgical intensive care patients solely based on quality controlled low-cost routine laboratory parameters is feasible.
Added Impact of Obesity and Insulin Resistance in Nocturnal Blood Pressure Elevation in Children and Adolescents
Authors: Lurbe Empar , Torro Isabel , Aguilar Francisco , Alvarez Julio , Alcon Jose , Pascual Jose Maria , Redon Josep
Published: January 2008

The aim of the present study was to analyze the relationship between insulin resistance and the ambulatory blood pressure components in obese children and adolescents. Eighty-seven overweight and obese white children and adolescents of both sexes, of European origin from 6 to 18 years of age (mean age: 10.9±2.7 years), were selected. Obesity was defined on the basis of a threshold body mass index
z
score >2 (Cole’s least mean square method) and overweight with a body mass index from the 85th to 97th percentile. A validated oscillometric method was used to measure ambulatory BP (Spacelabs 90207) during 24 hours. Fasting glucose and insulin were measured, and the homeostasis model assessment index was calculated. Subjects were grouped into tertiles of homeostasis model assessment index. No significant differences in terms of age, sex, and body mass index
z
score distribution were observed among groups. When adjusted by age, sex, and height, nocturnal systolic blood pressure and heart rate were significantly higher in subjects in the highest homeostasis model assessment index tertile (>4.7) as compared with those of the other groups, whereas no differences were observed for awake systolic blood pressure or heart rate. Whereas body mass index
z
score was more closely related with blood pressure and heart rate values, waist circumference was strongly related with insulin resistance. Moreover, both waist circumference and insulin resistance were mainly associated with higher nocturnal but not with awake blood pressure. The early increment of nocturnal blood pressure and heart rate associated with hyperinsulinemia may be a harbinger of hypertension-related insulin resistance and may contribute to heightened cardiovascular risk associated with this condition.
Behavioural responses of Canis familiaris to different tail lengths of a remotely-controlled life-size dog replica
Authors: Reimchen  , Leaver
Published: January 2008

The tail of dogs and allies (Canidae) is important for intraspecific communication. We used a life-sized dog model and varied the tail length and motion as an experimental method of examining effects of tail-docking on intraspecific signaling in domestic dogs, Canis familiaris. We videotaped interactions of 492 off-leash dogs and quantified size and behaviour of approaching dogs to the model's four tail conditions (short/still, short/wagging, long/still, long/wagging). Larger dogs were less cautious and more likely to approach a long/wagging tail rather than a long/still tail, but did not differ in their approach to a short/still and a short/wagging tail. Using discriminant analyses of behavioural variables, dogs responded with an elevated head and tail to a long/wagging tail model relative to the long/still tail model, but did not show any differences in response to tail motion when the model's tail was short. Our study provides evidence that a longer tail is more effective at conveying different intraspecific cues, such as those provided by tail motion, than a shorter tail and demonstrates the usefulness of robotic models when investigating complex behavioural interactions.