bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacokinetics, Safety, and Hydrolysis of Oral Pyrroloquinazolinediamines Administered in Single and Multiple Doses in Rats
Authors: Li Qigui , Kozar Michael P. , Shearer Todd W. , Xie Lisa H. , Lin Ai J. , Smith Kirsten S. , Si Yuanzheng , Anova Lalaine , Zhang Jing , Milhous Wilbur K. , Skillman Donald R.
Published: June 2007

Pyrroloquinazolinediamine (PQD) derivatives such as tetra-acetamide PQD (PQD-A4) and bis-ethylcarbamyl PQD (PQD-BE) were much safer (with therapeutic indices of 80 and 32, respectively) than their parent compound, PQD (therapeutic index, 10). Further evaluation of PQD-A4 and PQD-BE in single and multiple pharmacokinetic (PK) studies as well as corresponding toxicity studies was conducted with rats. PQD-A4 could be converted to two intermediate metabolites (monoacetamide PQD and bisacetamide PQD) first and then to the final metabolite, PQD, while PQD-BE was directly hydrolyzed to PQD without precursor and intermediate metabolites. Maximum tolerant doses showed that PQD-A4 and PQD-BE have only 1/12 and 1/6, respectively, of the toxicity of PQD after a single oral dose. Compared to the area under the concentration-time curve for PQD alone (2,965 ng·h/ml), values measured in animals treated with PQD-A4 and PQD-BE were one-third (1,047 ng·h/ml) and one-half (1,381 ng·h/ml) as high, respectively, after an equimolar dosage, suggesting that PQD was the only agent to induce the toxicity. Similar results were also shown in multiple treatments; PQD-A4 and PQD-BE generated two-fifths and three-fifths, respectively, of PQD concentrations, with 8.8-fold and 3.8-fold safety margins, respectively, over the parent drug. PK data indicated that the bioavailability of oral PQD-A4 was greatly limited at high dose levels, that PQD-A4 was slowly converted to PQD via a sequential three-step process of conversion, and that PQD-A4 was significantly less toxic than the one-step hydrolysis drug, PQD-BE. It was concluded that the slow and smaller release of PQD was the main reason for the reduction in toxicity and that the active intermediate metabolites can still maintain antimalarial potency. Therefore, the candidate with multiple-step hydrolysis of PQD could be developed as a safer potential agent for malaria treatment.
Dexamethasone as Adjuvant Therapy to Moxifloxacin Attenuates Valve Destruction in Experimental Aortic Valve Endocarditis Due to
Staphylococcus aureus
Authors: Skiadas Ioannis , Pefanis Angelos , Papalois Apostolos , Kyroudi Aspasia , Triantafyllidi Helen , Tsaganos Thomas , Giamarellou Helen
Published: June 2007

Although the beneficial effects of dexamethasone have frequently been investigated in various serious-infection settings, insufficient data on valve histology and cardiac function for infective endocarditis are available. The efficacy of moxifloxacin for the treatment of experimental aortic valve endocarditis due to methicillin-susceptible
Staphylococcus aureus
and the long-term effects of dexamethasone were evaluated in the current study. Sixty-eight rabbits were randomly assigned to four groups: A, B, C, and D. Group A consisted of 18 animals and functioned as a control group. Groups B and C consisted of 11 and 23 subjects, respectively, which received moxifloxacin for 5 days in a human-like pharmacokinetic simulation. Group D consisted of 16 animals that were administered moxifloxacin plus dexamethasone (0.25 mg/kg of body weight twice a day intravenously). The group B animals were sacrificed a day after the completion of treatment, and group C and D animals were sacrificed after 12 days in order to monitor any possible relapse and allow microbiological, histopathological, and echocardiographic evaluation of the long-term effects of glucocorticoids. No differences in survival, sterilization rates, or inflammatory infiltration and calcification of valve tissue were observed among the treated groups. However, the degrees of valve damage and collagenization were significantly worse, the fibroblast content was higher, and fractional shortening of the left ventricle fluctuated significantly in group C compared to group D (all groups,
P
< 0.05). We concluded that dexamethasone treatment for experimental
S. aureus
endocarditis attenuates valve destruction and preserves overall cardiac function without impeding the efficacy of moxifloxacin.
Yersinia enterocolitica
Infection of Mice Reveals Clonal Invasion and Abscess Formation
Authors: Oellerich Mark F. , Jacobi Christoph A. , Freund Sandra , Niedung Katy , Bach Alexandra , Heesemann Jürgen , Trülzsch Konrad
Published: June 2007

Yersinia enterocolitica
is a common cause of food-borne gastrointestinal disease leading to self-limiting diarrhea and mesenteric lymphadenitis. Occasionally, focal abscess formation in the livers and spleens of certain predisposed patients (those with iron overload states such as hemochromatosis) is observed. In the mouse oral infection model, yersiniae produce a similar disease involving the replication of yersiniae in the small intestine, the invasion of Peyer's patches, and dissemination to the liver and spleen. In these tissues and organs, yersiniae are known to replicate predominately extracellularly and to form microcolonies. By infecting mice orally with a mixture of equal amounts of green- and red-fluorescing yersiniae (yersiniae expressing green or red fluorescent protein), we were able to show for the first time that yersiniae produce exclusively monoclonal microcolonies in Peyer's patches, the liver, and the spleen, indicating that a single bacterium is sufficient to induce microcolony and microabscess formation in vivo. Furthermore, we present evidence for the clonal invasion of Peyer's patches from the small intestine. The finding that only very few yersiniae are required to establish microcolonies in Peyer's patches is due to both
Yersinia
-specific and host-specific factors. We demonstrate that yersiniae growing in the small intestinal lumen show strongly reduced levels of invasin, the most important factor for the early invasion of Peyer's patches. Furthermore, we show that the host severely restricts sequential microcolony formation in previously infected Peyer's patches.
Factor H Binding to PspC ofStreptococcus pneumoniaeIncreases Adherence to Human Cell Lines In Vitro and Enhances Invasion of Mouse Lungs In Vivo
Authors: Quin Lisa R. , Onwubiko Chinwendu , Moore Quincy C. , Mills Megumi Fujioka , McDaniel Larry S. , Carmicle Stephanie
Published: June 2007

Pneumococcal surface protein C (PspC) binds to both human secretory immunoglobulin A (sIgA) and complement factor H (FH). FH, a regulator of the alternative pathway of complement, can also mediate adherence of different host cells. Since PspC contributes to adherence and invasion of host cells, we hypothesized that the interaction of PspC with FH may also mediate adherence of pneumococci to human cells. In this study, we investigated FH- and sIgA-mediated pneumococcal adherence to human cell lines in vitro. Adherence assays demonstrated that preincubation ofStreptococcus pneumoniaeD39 with FH increased adherence to human umbilical vein endothelial cells (HUVEC) 5-fold and to lung epithelial cells (SK-MES-1) 18-fold, relative to that of D39 without FH on the surface. The presence of sIgA enhanced adherence to SK-MES-1 6-fold and to pharyngeal epithelial cells (Detroit 562) 14-fold. Furthermore, sIgA had an additive effect on adherence to HUVEC; specifically, preincubation of D39 with both FH and sIgA led to a 21-fold increase in adherence. Finally, using a mouse model, we examined the significance of the FH-PspC interaction in pneumococcal nasal colonization and lung invasion. Mice intranasally infected with D39 preincubated with FH had increased bacteremia and lung invasion, but they had similar levels of nasopharyngeal colonization compared to that of mice challenged with D39 without FH.
Role of the Omp25/Omp31 Family in Outer Membrane Properties and Virulence ofBrucella ovis
Authors: Caro-Hernández Paola , Fernández-Lago Luis , de Miguel María-Jesús , Martín-Martín Ana I. , Cloeckaert Axel , Grilló María-Jesús , Vizcaíno Nieves
Published: June 2007

The genes coding for the five outer membrane proteins (OMPs) of the Omp25/Omp31 family expected to be located in the outer membrane (OM) of rough virulentBrucella ovisPA were inactivated to evaluate their role in virulence and OM properties. The OM properties of the mutant strains and of the mutants complemented with the corresponding wild-type genes were analyzed, in comparison with the parental strain and roughB. abortusRB51, in several tests: (i) binding of anti-Omp25 and anti-Omp31 monoclonal antibodies, (ii) autoagglutination of bacterial suspensions, and (iii) assessment of susceptibility to polymyxin B, sodium deoxycholate, hydrogen peroxide, and nonimmune ram serum. A tight balance of the members of the Omp25/Omp31 family was seen to be essential for the stability of theB. ovisOM, and important differences between the OMs ofB. ovisPA andB. abortusRB51 rough strains were observed. Regarding virulence, the absence of Omp25d and Omp22 from the OM ofB. ovisPA led to a drastic reduction in spleen colonization in mice. While the greater susceptibility of the Δomp22mutant to nonimmune serum and its difficulty in surviving in the stationary phase might be on the basis of its dramatic attenuation, no defects in the OM able to explain the attenuation of the Δomp25dmutant were found, especially considering that the fully virulent Δomp25cmutant displayed more important OM defects. Accordingly, Omp25d, and perhaps Omp22, could be directly involved in the penetration and/or survival ofB. ovisinside host cells. This aspect, together with the role of Omp25d and Omp22 in the virulence both ofB. ovisin rams and of otherBrucellaspecies, should be thoroughly evaluated in future studies.
Increasing the Interaction of
Borrelia burgdorferi
with Decorin Significantly Reduces the 50 Percent Infectious Dose and Severely Impairs Dissemination
Authors: Xu Qilong , Seemanaplli Sunita V. , McShan Kristy , Liang Fang Ting
Published: June 2007

Tight regulation of surface antigenic expression is crucial for the pathogenic strategy of the Lyme disease spirochete,
Borrelia burgdorferi
. Here, we report the influence of increasing expression of decorin-binding protein A (DbpA), one of the most investigated spirochetal surface adhesins, on the 50% infectious dose (ID
50
), dissemination, tissue colonization, pathogenicity, and persistence of
B. burgdorferi
in the murine host. Our in vitro assays showed that increasing DbpA expression dramatically increased the interaction of
B. burgdorferi
with decorin and sensitivity to growth inhibition/killing by anti-DbpA antibodies; however, this increased interaction did not affect spirochetal growth and replication in the presence of decorin. Increasing DbpA expression significantly reduced ID
50
values and severely impaired dissemination in severe combined immunodeficiency (SCID) and immunocompetent mice. During infection of SCID mice,
B. burgdorferi
with increased DbpA expression was able to effectively colonize heart and skin tissues, but not joint tissues, completely abrogating arthritis virulence. Although increasing DbpA expression did not affect spirochetal persistence in the skin, it diminished the ability of
B. burgdorferi
to persist in the heart and joint tissues during chronic infection of immunocompetent mice. Taken together, the study highlights the importance of controlling surface antigen expression in the infectivity, dissemination, tissue colonization, pathogenicity, and persistence of
B. burgdorferi
during mammalian infection.
Development and Application of an Oral Challenge Mouse Model for StudyingClostridium perfringensType D Infection
Authors: Fernandez-Miyakawa Mariano E. , Sayeed Sameera , Fisher Derek J. , Poon Rachael , Adams Vicki , Rood Julian I. , McClane Bruce A. , Saputo Julian , Uzal Francisco A.
Published: June 2007

Clostridium perfringenstype D isolates cause enterotoxemia in sheep, goats, and probably cattle. While the major disease signs and lesions of type D animal disease are usually attributed to epsilon toxin, a class B select agent, these bacteria typically produce several lethal toxins. Understanding of disease pathogenesis and development of improved vaccines are hindered by the lack of a small-animal model mimicking natural disease caused by type D isolates. Addressing this need, we developed an oral challenge mouse model ofC. perfringenstype D enterotoxemia. When BALB/c mice with a sealed anus were inoculated by intragastric gavage with type D isolates, 7 of 10 type D isolates were lethal, as defined by spontaneous death or severe clinical signs necessitating euthanasia. The lethalities of the seven type D isolates varied between 14 and 100%. Clinical signs in the lethally challenged mice included seizures, convulsions, hyperexcitability, and/or depression. Mild intestinal gas distention and brain edema were observed at necropsy in a few mice, while histology showed multifocal acute tubular necrosis of the kidney and edema in the lungs of most challenged mice that developed a clinical response. When the lethality of type D isolates in this model was compared with in vitro toxin production, only a limited correlation was observed. However, mice could be protected against lethality by intravenous passive immunization with an epsilon toxin antibody prior to oral challenge. This study provides an economical new model for studying the pathogenesis ofC. perfringenstype D infections.
Borrelia gariniiInduces CXCL13 Production in Human Monocytes through Toll-Like Receptor 2
Authors: Rupprecht Tobias A. , Kirschning Carsten J. , Popp Bernadette , Kastenbauer Stefan , Fingerle Volker , Pfister Hans-Walter , Koedel Uwe
Published: June 2007

Recent studies have suggested an important role for the B-cell-attracting chemokine CXCL13 in the B-cell-dominated cerebrospinal fluid (CSF) infiltrate in patients with neuroborreliosis (NB). High levels of CXCL13 were present in the CSF of NB patients. It has not been clear, however, whether high CSF CXCL13 titers are specific for NB or are a characteristic of other spirochetal diseases as well. Furthermore, the mechanisms leading to the observed CXCL13 expression have not been identified yet. Here we describe similarly elevated CSF CXCL13 levels in patients with neurosyphilis, while pneumococcal meningitis patient CSF do not have high CXCL13 levels. In parallel, challenge of human monocytes in vitro with two of the spirochetal causative organisms,Borrelia garinii(theBorreliaspecies most frequently found in NB patients) andTreponema pallidum, but not challenge with pneumococci, induced CXCL13 release. This finding implies that a common spirochetal motif is a CXCL13 inducer. Accordingly, we found that the lipid moietyN-palmitoyl-S-(bis[palmitoyloxy]propyl)cystein (Pam3C) (three palmitoyl residues bound to N-terminal cysteine) of the spirochetal lipoproteins is critical for the CXCL13 induction in monocytes. As the Pam3C motif is known to signal via Toll-like receptor 2 (TLR2) and an anti-TLR2 monoclonal antibody blocked CXCL13 production of human monocytes incubated withB. garinii, this suggests that TLR2 is a major mediator ofBorrelia-induced secretion of CXCL13 from human monocytes.
Conserved Regions fromNeisseria gonorrhoeaePilin Are Immunosilent and Not Immunosuppressive
Authors: Hansen Johanna K. , Demick Karen P. , Mansfield John M. , Forest Katrina T.
Published: June 2007

PilE is the primary subunit of type IV pili fromNeisseria gonorrhoeaeand contains a surface-exposed hypervariable region thought to be one feature of pili that has prevented development of a pilin-based vaccine. We have created a three-dimensional structure-based antigen by replacing the hypervariable region of PilE with an aspartate-glutamine linker chosen from the sequence ofPseudomonas aeruginosaPilA. We then characterized murine immune responses to this novel protein to determine if conserved PilE regions could serve as a vaccine candidate. The control PilE protein elicited strong T-cell-dependent B-cell responses that are specific to epitopes in both the hypervariable deletion and control proteins. In contrast, the hypervariable deletion protein was unable to elicit an immune response in mice, suggesting that in the absence of the hypervariable region, the conserved regions of PilE alone are not sufficient for antibody production. Further analysis of these PilE proteins with suppressor cell assays showed that neither suppresses T- or B-cell responses, and flow cytometry experiments suggested that they do not exert suppressor effects by activating T regulatory cells. Our results show that in the murine model, the hypervariable region of PilE is required to activate immune responses to pilin, whereas the conserved regions are unusually nonimmunogenic. In addition, we show that both hypervariable and conserved regions of pilin are not suppressive, suggesting that PilE does not cause the decrease in T-cell populations observed during gonococcal cervicitis.
Severe spinal injuries in alpine skiing and snowboarding: a 6-year review of a tertiary trauma centre for the Bernese Alps ski resorts, Switzerland
Authors: Franz T , Hasler R M , Benneker L , Zimmermann H , Siebenrock K A , Exadaktylos A K
Published: June 2007

Objective:

To analyse the epidemiological data, injury pattern, clinical features and mechanisms of severe spinal injuries related to alpine skiing and snowboarding.

Study design:

A six-year review of all adult patients with severe spinal injuries sustained from alpine skiing or snowboarding.

Setting:

Tertiary trauma centre in Bern, Switzerland.

Patients and methods:

All adult patients (over 16 years of age) admitted to a tertiary trauma centre from 1 July 2000, through 30 June 2006, were reviewed using a computerised database. From these records, a total of 728 patients injured from snow sports were identified. Severe spinal injuries (defined as spinal fractures, subluxations, dislocations or concomitant spinal cord injuries) were found in 73 patients (17 female, 56 male). The clinical features of these patients were reviewed with respect to epidemiological factors, mechanism of injury, fracture pattern, and neurological status.

Results:

The majority of severe spinal injuries (n = 63) were related to skiing. Fatal central-nervous injuries and transient or persistent neurological symptoms occurred in 28 patients (23 skiers, 5 snowboarders). None of the snowboarders suffered from persistent neurological sequelae. Snowboarders with severe spinal injuries (n = 10) were all male (p<0.05), and were significantly younger than skiers (p<0.001). The most commonly affected site was the lumbar spine. However, 39 patients (53.4%) suffered from injury pattern at two or more levels.

Conclusions:

With advances in technology and slope maintenance, skiers and snowboarders progress to higher skill levels and faster speeds more rapidly than ever before. Great efforts have been focused on reducing extremity injuries in snow sports, but until recently very little attention has been given to spinal injury prevention on the slopes. Suggestions for injury prevention include the use of spine protectors, participation on appropriate runs for ability level, proper fit and adjustment of equipment, and taking lessons with the goal of increasing ability and learning hill etiquette.
Old ways, new means: tobacco industry funding of academic and private sector scientists since the Master Settlement Agreement
Authors: Schick Suzaynn F , Glantz Stanton A
Published: June 2007

When, as a condition of the Master Settlement Agreement (MSA) in 1998, US tobacco companies disbanded the Council for Tobacco Research and the Center for Indoor Air Research, they lost a vital connection to scientists in academia and the private sector. The aim of this paper was to investigate two new research projects funded by US tobacco companies by analysis of internal tobacco industry documents now available at the University of California San Francisco (San Francisco, California, USA) Legacy tobacco documents library, other websites and the open scientific literature. Since the MSA, individual US tobacco companies have replaced their industry-wide collaborative granting organisations with new, individual research programmes. Philip Morris has funded a directed research project through the non-profit Life Sciences Research Office, and British American Tobacco and its US subsidiary Brown and Williamson have funded the non-profit Institute for Science and Health. Both of these organisations have downplayed or concealed their true level of involvement with the tobacco industry. Both organisations have key members with significant and long-standing financial relationships with the tobacco industry. Regulatory officials and policy makers need to be aware that the studies these groups publish may not be as independent as they seem.
Out of the smokescreen II: will an advertisement targeting the tobacco industry affect young people’s perception of smoking in movies and their intention to smoke?
Authors: Edwards Christine , Oakes Wendy , Bull Diane
Published: June 2007

Objective:To evaluate the effect of an antismoking advertisement on young people’s perceptions of smoking in movies and their intention to smoke.

Subjects/setting:3091 cinema patrons aged 12–24 years in three Australian states; 18.6% of the sample (n = 575) were current smokers.

Design/intervention:Quasi-experimental study of patrons, surveyed after having viewed a movie. The control group was surveyed in week 1, and the intervention group in weeks 2 and 3. Before seeing the movie in weeks 2 and 3, a 30 s antismoking advertisement was shown, shot in the style of a movie trailer that warned patrons not to be sucked in by the smoking in the movie they were about to see.

Outcomes:Attitude of current smokers and non-smokers to smoking in the movies; intention of current smokers and non-smokers to smoke in 12 months.

Results:Among non-smokers, 47.8% of the intervention subjects thought that the smoking in the viewed movie was not OK compared with 43.8% of the control subjects (p = 0.04). However, there was no significant difference among smokers in the intervention (16.5%) and control (14.5%) groups (p = 0.4). A higher percentage of smokers in the intervention group indicated that they were likely to be smoking in 12 months time (38.6%) than smokers in the control group (25.6%; p<0.001). For non-smokers, there was no significant difference in smoking intentions between groups, with 1.2% of intervention subjects and 1.6% of controls saying that they would probably be smoking in 12 months time (p = 0.54).

Conclusions:This real-world study suggests that placing an antismoking advertisement before movies containing smoking scenes can help to immunise non-smokers against the influences of film stars’ smoking. Caution must be exercised in the type of advertisement screened as some types of advertising may reinforce smokers’ intentions to smoke.
Dependence of tar, nicotine and carbon monoxide yields on physical parameters: implications for exposure, emissions control and monitoring
Authors: Stephens W E
Published: June 2007

Objective:To estimate the extent to which tar, nicotine and carbon monoxide (TNCO) yields are dependent on cigarette design features such as burn rate, filter ventilation and paper porosity, and to consider the implications for human exposure and the regulation of TNCO emissions. A related aim is to determine whether accurate prediction of TNCO yields is possible using only simple physical parameters.

Design and methods:Datasets that include quantitative design parameters as well as measurements of TNCO yields collected under standard conditions with vents unblocked (International Organization for Standardization) and under intense conditions with vents fully blocked (Health Canada) were compiled from the literature (primarily US and UK brands). Forward stepwise multiple regression analysis is used to assess the relative importance of each design feature in explaining variability in the observed emissions. Using randomly split data subsets, multiple linear regression is used to model the dependence of TNCO yields on design features in the training subset and validated against the test subset. Tar and carbon monoxide correlate with many of the particulate- and volatile-phase toxins in smoke, and brand values normalised to nicotine yield are used as surrogate measures of exposure within the bounds defined by non-intense and intense smoking protocols.

Results and conclusions:Filter ventilation is the dominant control on measured TNCO emissions, but other factors including burn rate, amount of tobacco and paper porosity also contribute. Yields are predictable with reasonable accuracy and precision using only measured physical parameters. Surrogate exposure indicators suggest that filter ventilation does not lead to any reduction in exposure and that highly ventilated (low-yield) brands may actually increase exposure to the more volatile toxins.
Reconsidering stress and smoking: a qualitative study among college students
Authors: Nichter Mark , Nichter Mimi , Carkoglu Asli ,   the Tobacco Etiology Research Network
Published: June 2007

Background:Although it is widely acknowledged among adult smokers that increases in smoking are often precipitated by stressful events, far less attention has been given to smoking during times of stress among youth.

Aims:To address this gap by drawing attention to the social utility of smoking in contexts associated with stress among college students.

Design:Face-to-face semistructured interviews with college freshmen at a large midwestern university in the US.

Participants:Male and female low-level smokers (n = 24), defined as those who reported regular weekday smoking (typically 3–4 cigarettes a day) and smoking at parties on weekends, were interviewed once in person. In addition, 40 brief interviews with smokers were conducted during final examination.

Measurements:Interviews focused on a range of issues including current smoking behaviour and reasons for smoking. As part of the interview, students were given a deck of cards that listed a range of reasons for smoking. Participants were asked to select cards that described their smoking experience in the past 2 weeks. Those who selected cards that indicated smoking when stressed were asked to explain the reasons why they did so.

Results:A review of qualitative responses reveals that smoking served multiple functions during times of stress for college students. Cigarettes are a consumption event that facilitates a brief social interaction during study times when students feel isolated from their friends. Cigarettes also serve as an idiom of distress, signalling non-verbally to others that they were stressed. Students described smoking to manage their own stress and also to help manage “second-hand stress” from their friends and classmates.

Conclusions:Moving away from an individual-focused analysis of stress to a broader assessment of the social contexts of smoking provides a more nuanced account of the multifunctionalilty of cigarettes in students’ lives. Qualitative research draws attention to issues including the need for smoking and socialising during examination time, smoking as a way to take a break and refocus, notions of second-hand stress and smoking to manage social relationships.
GEOMETRY OF HOMOCLINIC CONNECTIONS IN A PLANAR CIRCULAR RESTRICTED THREE-BODY PROBLEM
Authors: GIDEA MARIAN , MASDEMONT JOSEP J.
Published: June 2007

The stable and unstable invariant manifolds associated with Lyapunov orbits about the libration point L1between the primaries in the planar circular restricted three-body problem with equal masses are considered. The behavior of the intersections of these invariant manifolds for values of the energy between that of L1and the other collinear libration points L2, L3is studied using symbolic dynamics. Homoclinic orbits are classified according to the number of turns about the primaries.
ATTRACTOR MODELING AND EMPIRICAL NONLINEAR MODEL REDUCTION OF DISSIPATIVE DYNAMICAL SYSTEMS
Authors: BOLLT ERIK
Published: June 2007

In a broad sense, model reduction means producing a low-dimensional dynamical system that replicates either approximately, or more strictly, exactly and topologically, the output of a dynamical system. Model reduction has an important role in the study of dynamical systems and also with engineering problems. In many cases, there exists a good low-dimensional model for even very high-dimensional systems, even infinite dimensional systems in the case of a PDE with a low-dimensional attractor. The theory of global attractors approaches these issues analytically, and focuses on finding (depending on the question at hand), a slow-manifold, inertial manifold, or center manifold, on which a restricted dynamical system represents the interesting behavior of the dynamical system; the main issue depends on defining a stable invariant manifold in which the dynamical system is invariant. These approaches are analytical in nature, however, and are therefore not always appropriate for dynamical systems known only empirically through a dataset. Empirically, the collection of tools available are much more restricted, and are essentially linear in nature. Usually variants of Galerkin's method, project the dynamical system onto a function linear subspace spanned by modes of some chosen spanning set. Even the popular Karhunen–Loeve decomposition, or POD, method is exactly such a method. As such, it is forced to either make severe errors in the case that the invariant space is intrinsically a highly nonlinear manifold, or bypass low-dimensionality by retaining many modes in order to capture the manifold. In this work, we present a method of modeling a low-dimensional nonlinear manifold known only through the dataset. The manifold is modeled as a discrete graph structure. Intrinsic manifold coordinates will be found specifically through the ISOMAP algorithm recently developed in the Machine Learning community originally for purposes of image recognition.
STRUCTURE OF THE ATTRACTOR OF THE CAHN–HILLIARD EQUATION ON A SQUARE
Authors: MAIER-PAAPE STANISLAUS , MISCHAIKOW KONSTANTIN , WANNER THOMAS
Published: June 2007

We describe the fine structure of the global attractor of the Cahn–Hilliard equation on two-dimensional square domains. This is accomplished by combining recent numerical results on the set of equilibrium solutions due to [Maier-Paape & Miller, 2002] with algebraic Conley index techniques. Using the information on the set of equilibria as assumption, we build Morse decompositions and connection matrices. The latter imply existence of heteroclinic connections between the equilibria inside the attractor. While path-following of the parameter range of Cahn–Hilliard, we find more and more complicated dynamical behavior. One of our main results describes the fine structure of the attractor for mean mass zero with four stable cosine structured equilibria and eight other stable equilibria that have a quarter circle nodal line. Besides that, we also study the attractor in symmetry fixed point spaces where we, for example, find nonunique connection matrices and saddle–saddle connections of Morse sets.
DYNAMICS AND ACTIVE CONTROL OF MOTION OF A DRIVEN MULTI-LIMIT-CYCLE VAN DER POL OSCILLATOR
Authors: YAMAPI R. , NANA NBENDJO B. R. , ENJIEU KADJI H. G.
Published: June 2007

This paper deals with the dynamics and active control of a driven multi-limit-cycle Van der Pol oscillator. The amplitude of the oscillatory states both in the autonomous and nonautonomous case are derived. The interaction between the amplitudes of the external excitation and the limit-cycles are also analyzed. The domain of the admissible values on the amplitude for the external excitation is found. The effects of the control parameter on the behavior of a driven multi-limit-cycle Van der Pol model are analyzed and it appears that with the appropriate selection of the coupling parameter, the quenching of chaotic vibrations takes place.
HOPF BIFURCATION OF A DELAYED DIFFERENTIAL EQUATION
Authors: GUO QIAN , LI CHANGPIN
Published: June 2007

In this paper, we study Hopf bifurcation of a second-order nonlinear differential equation with time delay by using the Lyapunov–Schmidt reduction. The approximate analytical expressions of the periodic solutions bifurcated from the trivial solution are given. We also discuss the stability of these periodic solutions. The numerical simulations line up with the theoretical results.
ADVANCED IMAGE PROCESSING CELLULAR NEURAL NETWORKS
Authors: ITOH MAKOTO , CHUA LEON O.
Published: June 2007

Many useful and well-known image processing templates for cellular neural networks (CNN's) can be derived from neural field models, thereby providing a neural basis for the CNN paradigm. The potential ability of multitasking image processing is investigated by using these templates. Many visual illusions are simulated via CNN image processing. The ability of the CNN to mimic such high-level brain functions suggests possible applications of the CNN in cognitive engineering. Furthermore, two kinds of painting-like image processings, namely, texture generation and illustration style transformation are investigated.
MINIMIZING THE MAKESPAN FOR UNRELATED PARALLEL MACHINES
Authors: GUO YUNSONG , LIM ANDREW , RODRIGUES BRIAN , YANG LIANG
Published: June 2007

In this paper, we study the unrelated parallel machine problem for minimizing the makespan, which is NP-hard. We used Simulated Annealing (SA) and Tabu Search (TS) with Neighborhood Search (NS) based on the structure of the problem. We also used a modified SA algorithm, which gives better results than the traditional SA and developed an effective heuristic for the problem: Squeaky Wheel Optimization (SWO) hybrid with TS. Experimental results average 2.52% from the lower bound and are within acceptable timescales improving current best results for the problem.
SYNTHESIS OF HEAVIEST ELEMENTS (RESULTS AND PROSPECTS)
Authors: OGANESSIAN YURI
Published: June 2007

The formation and decay properties of the heaviest nuclei with Z = 112 - 116 and 118 were studied in the reactions 238 U , 242,244 Pu , 243 Am , 245,248 Cm and 249 Cf +48 Ca . The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission. The total time of decays ranges from 0.5 ms to about 1 day, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268 Db (TSF ≈ 30 h ), the final product in the chain of α-decays of the odd–odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104 - 118 and N = 162 - 177 gives evidence for the decisive influence of the structure of superheavy nuclei on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature (cosmic rays) and prospects of superheavy element research are also presented.
HEAVY PARTICLE RADIOACTIVITIES
Authors: POENARU D. N. , GHERGHESCU R. A. , PLONSKI I. H. , GREINER W.
Published: June 2007

The potential energy surface for binary decay modes of 228 Th versus the distance between the fragment centers and the mass asymmetry is calculated by using the macroscopic-microscopic model with energy levels obtained within the most advanced asymmetric two center shell model. The valley due to 20 O radioactivity is evidenced as a result of the very strong shell effects due to the doubly magic daughter 208 Pb . For the first time the potential barrier of this decay mode is produced by adding the shell and pairing corrections to the phenomenological deformation energy. The half-lives of cluster emitters predicted by the analytical superasymmetric fission model have been confirmed in all measurements performed until now.
HADRONIC MATTER AND NUCLEI IN AN EFFECTIVE MODEL
Authors: SCHRAMM S. , ZSCHIESCHE D. , ZEEB G. , LINN K.-N.
Published: June 2007

We investigate hadronic matter and nuclear properties within an effective chiral model description. We study nuclear structure properties including nuclear deformation over a wide range of nuclei. Some results on neutron star properties within the model will be presented. We discuss the phase structure of the model at high temperatures and densities in comparison to lattice calculations.
THE NUCLEAR AND MANY-BODY PHYSICS OF SUPERNOVA EXPLOSIONS
Authors: STROTHER TERRANCE , BAUER WOLFGANG
Published: June 2007

Motivated by the success of kinetic theory in the description of observables in intermediate and high energy heavy ion collisions, we use kinetic theory to model the dynamics of collapsing iron cores in type II supernova explosions. The algorithms employed, the rational for choosing them, and some preliminary results are discussed.
MATTER UNDER STRONG GRAVITY
Authors: BOLLER THOMAS
Published: June 2007

I report on the discovery of high density matter in the immediate vicinity of the central black holes in the Narrow-Line Seyfert 1 Galaxies 1H 0707-495 and IRAS 13224–3809. The density of these clouds is of the order of 1019 cm -3. The clouds are neutral for Fe and must be embedded into the accretion disc to explain the observations. This results in a partial covering interpretation, where the clouds partially absorb the emission from the accretion disc and part of the emission reaches the observer unabsorbed, leading to a strong soft excess, a sharp Fe K edge without any detectable Fe K reemission. This scenario has been proposed theoretically first by M. Rees in 1987 and appears now to be observationally confirmed with observations of the X-ray observatory XMM-Newton.
COSMIC RAYS AT THE HIGHEST ENERGIES — FIRST DATA FROM THE PIERRE AUGER OBSERVATORY
Authors:   FOR THE PIERRE AUGER COLLABORATION., KAMPERT KARL-HEINZ
Published: June 2007

The southern Pierre Auger Observatory, presently under construction in Malargüe, Argentina, is nearing completion. The instrument is designed to measure extensive air-showers with energies ranging from 1018-1020 eV and beyond. It combines two complementary observation techniques; the detection of particles at ground and the coincident observation of associated fluorescence light generated in the atmosphere above the ground. This is being realized by employing an array of 1600 water Cherenkov detectors, distributed over an area of 3000 km2, and operating 24 wide-angle Schmidt telescopes, positioned at four sites at the border of the ground array. The Observatory will reach its full size only in 2007 but data are routinely recorded already and have started to provide relevant science results. This talk will focus on the detector characterizations and presents first results on the arrival direction of extremely-high energy cosmic rays, their energy spectrum, and on the upper limit of the photon fraction.
STRANGE PARTICLES AND NEUTRON STARS — EXPERIMENTS AT GSI
Authors: SENGER PETER
Published: June 2007

Experiments on strangeness production in nucleus-nucleus collisions at SIS energies address fundamental aspects of modern nuclear physics: the determination of the nuclear equation-of-state at high baryon densities and the properties of hadrons in dense nuclear matter. Experimental data and theoretical results will be reviewed. Future experiments at the FAIR accelerator aim at the exploration of the QCD phase diagram at highest baryon densities.
THE R-PROCESS: SUPERNOVAE AND OTHER SOURCES OF THE HEAVIEST ELEMENTS
Authors: THIELEMANN F.-K. , MOCELJ D. , PANOV I. , KOLBE E. , RAUSCHER T. , KRATZ K.-L. , FAROUQI K. , PFEIFFER B. , MARTINEZ-PINEDO G. , KELIC A. , LANGANKE K. , SCHMIDT K.-H. , ZINNER N.
Published: June 2007

Rapid neutron capture in stellar explosions is responsible for the heaviest elements in nature, up to Th , U and beyond. This nucleosynthesis process, the r-process, is unique in the sense that a combination of nuclear physics far from stability (masses, half-lives, neutron-capture and photodisintegration, neutron-induced and beta-delayed fission and last but not least neutrino-nucleus interactions) is intimately linked to ejecta from astrophysical explosions (core collapse supernovae or other neutron star related events). The astrophysics and nuclear physics involved still harbor many uncertainties, either in the extrapolation of nuclear properties far beyond present experimental explorations or in the modeling of multidimensional, general relativistic (neutrino-radiation) hydrodynamics with rotation and possibly required magnetic fields. Observational clues about the working of the r-process are mostly obtained from solar abundances and from the abundance evolution of the heaviest elements as a function of galactic age, as witnessed in old extremely metal-poor stars. They contain information whether the r-process is identical for all stellar events, how abundance features develop with galactic time and whether the frequency of r-process events is comparable to that of average core collapse supernovae - producing oxygen through titanium, as well as iron-group nuclei. The theoretical modeling of the r-process has advanced from simple approaches, where the use of static neutron densities and temperatures can aid to test the influence of nuclear properties far from stability on abundance features, to more realistic expansions with a given entropy, global neutron/proton ratio and expansion timescales, as expected from explosive astrophysical events. The direct modeling in astrophysical events such as supernovae still faces the problem whether the required conditions can be met.
THE WONDERFUL WORLD OF WALLYWOOD
Authors: MCLERRAN L.
Published: June 2007

This paper presents a personal account of the scientific and professional adventures of Walter Greiner. It is based on an "after dinner talk" given for the celebration of his 70'th birthday held at the Frankfurt Institute for Advanced Studies on April 3-6, 2006.
MARKOV STATES AND CHAINS ON THE CAR ALGEBRA
Authors: ACCARDI LUIGI , FIDALEO FRANCESCO , MUKHAMEDOV FARRUH
Published: June 2007

We introduce the notion of Markov states and chains on the Canonical Anticommutation Relations algebra over ℤ, emphasizing some remarkable differences with the infinite tensor product case. We describe the structure of the Markov states on this algebra and show that, contrarily to the infinite tensor product case, not all these states are diagonalizable. A general method to construct nontrivial quantum Markov chains on the CAR algebra is also proposed and illustrated by some pivotal examples. This analysis provides a further step for a satisfactory theory of quantum Markov processes.
ROTATION INVARIANT INTERACTING FOCK SPACES
Authors: CRISMALE VITONOFRIO , LU YUN GANG
Published: June 2007

In this paper we give a necessary and sufficient condition on the interacting Fock (IFF) space by which the vacuum distribution of the position operator is rotation invariant.
GRÖBNER BASIS TECHNIQUES TO COMPUTE WEIGHT DISTRIBUTIONS OF SHORTENED CYCLIC CODES
Authors: SALA MASSIMILIANO
Published: June 2007

Using Gröbner techniques, we can exhibit a method to get the distance and weight distribution of cyclic codes and shortened cyclic codes, improving earlier similar results for the distance of cyclic codes.
SIMPLIFYING SUMS IN ΠΣ*-EXTENSIONS
Authors: SCHNEIDER CARSTEN
Published: June 2007

We present telescoping algorithms which compute optimal sum representations of indefinite nested sums. More precisely, given a rational summand expression in terms of nested sums and products, the algorithm splits the summand into a summable part, which can be summed by telescoping, and into a non-summable part, which is degree-optimal with respect to one of the most nested sums or products. If possible, all the most nested sums and products can be eliminated in the non-summable part. We illustrate our summation algorithms by various concrete examples.
A MACWILLIAMS FORMULA FOR CONVOLUTIONAL CODES
Authors: SOLÉ PATRICK , ZINOVIEV DMITRII
Published: June 2007

Regarding convolutional codes as polynomial analogues of arithmetic lattices, we derive a Poisson–Jacobi formula for their trivariate weight enumerator. The proof is based on harmonic analysis on locally compact abelian groups as developed in Tate's thesis to derive the functional equation of the zeta function.
NEW EXPLICIT MULTIPLICATIVE RELATIONS BETWEEN GAUSS SUMS
Authors: VAN WAMELEN PAUL
Published: June 2007

We study multiplicative identities between Gauss sums. If such an identity does not follow from the Davenport–Hasse relation and the norm relation, it is called a sign ambiguity. Until recently only a finite number of explicit sign ambiguities were known. We generalize the first infinite family of sign ambiguities as found by Murray.
IDENTITIES OF THE ROGERS–RAMANUJAN–SLATER TYPE
Authors: SILLS ANDREW V.
Published: June 2007

It is shown that (two-variable generalizations of) more than half of Slater's list of 130 Rogers–Ramanujan identities (L. J. Slater, Further identities of the Rogers–Ramanujan type, Proc. London Math Soc. (2)54 (1952) 147–167) can be easily derived using just three multiparameter Bailey pairs and their associated q-difference equations. As a bonus, new Rogers–Ramanujan type identities are found along with natural combinatorial interpretations for many of these identities.
A NANOSTRUCTURED POLYMORPH OF μ-OXOBIS(PHTHALOCYANINATOIRON(III)) STUDIED BY ANGULAR AND ENERGY DISPERSIVE X-RAY DIFFRACTION
Authors: MATASSA ROBERTO , BALLIRANO PAOLO , DONZELLO MARIA PIA , ERCOLANI CLAUDIO , SADUN CLAUDIA , CAMINITI RUGGERO
Published: June 2007

A new approach of X-ray diffraction was used to investigate the nanostructured μ-Oxo(2) polymorph of μ-oxo-bis(phthalocyaninatoiron(III)), [ PcFe – O – FePc ]. The packing of the dinuclear units was determined by the Rietveld method on Angular Dispersive X-ray Diffraction (ADXD) data, whereas the intramolecular geometry was optimized by Energy Dispersive X-ray Diffraction (EDXD) exploiting the peculiar strength of those techniques. The dimension of the nanoparticles was estimated from the Fourier transform of the EDXD experimental structural function.
ELECTRON TRANSPORT THROUGH MOLECULAR CHAINS
Authors: MAITI SANTANU K.
Published: June 2007

We study electron transport through molecular chains attached with two nonsuperconducting electrodes by the use of Green's function technique. Here, we do parametric calculations based on the tight-binding model to characterize the electron transport through such bridge systems and see that the transport properties are significantly affected by (a) the length of the molecular chain and (b) the molecule-to-electrode coupling strength. In this context, we also discuss the steady state current fluctuations, so-called shot noise, which is a consequence of the quantization of charge and is not directly available through conductance measurements.