Endowing networks with desired symmetries and modular behavior.

Symmetries in a network regulate its organization into functional clustered states. Given a generic ensemble of nodes and a desirable cluster (or group of clusters), we exploit the direct connection between the elements of the eigenvector centrality and the graph symmetries to generate a network equipped with the desired cluster(s), with such a synthetical structure being furthermore perfectly reflected in the modular organization of the network's functioning. Our results solve a relevant problem of designing a desired set of clusters and are of generic application in all cases where a desired parallel functioning needs to be blueprinted.

Reply to "comment on 'how to obtain extreme multistability in coupled dynamical systems' ".

In this Reply we answer the two major issues raised by the Comment. First, we point out that the idea of constructing extreme multistability in simple dynamical systems is not new and has been demonstrated previously by other authors. Furthermore, we emphasize the importance of the concept of a conserved quantity and its consequences for the dynamics, which applies to all the examples in the Comment. Second, we show that the design of controllers to achieve extreme multistability in coupled systems is as general as described in Phys. Rev. E 85, 035202(R) (2012) by providing two examples which do not lead to a master-slave dynamics.

Diverse routes of transition from amplitude to oscillation death in coupled oscillators under additional repulsive links.

We report the existence of diverse routes of transition from amplitude death to oscillation death in three different diffusively coupled systems, which are perturbed by a symmetry breaking repulsive coupling link. For limit-cycle systems the transition is through a pitchfork bifurcation, as has been noted before, but in chaotic systems it can be through a saddle-node or a transcritical bifurcation depending on the nature of the underlying dynamics of the individual systems. The diversity of the routes and their dependence on the complex dynamics of the coupled systems not only broadens our understanding of this important phenomenon but can lead to potentially new practical applications.

Transition from amplitude to oscillation death in a network of oscillators.

We report a transition from a homogeneous steady state (HSS) to inhomogeneous steady states (IHSSs) in a network of globally coupled identical oscillators. We perturb a synchronized population of oscillators in the network with a few local negative or repulsive mean field links. The whole population splits into two clusters for a certain number of repulsive mean field links and a range of coupling strength. For further increase of the strength of interaction, these clusters collapse into a HSS followed by a transition to IHSSs where all the oscillators populate either of the two stable steady states. We analytically determine the origin of HSS and its transition to IHSS in relation to the number of repulsive mean-field links and the strength of interaction using a reductionism approach to the model network. We verify the results with numerical examples of the paradigmatic Landau-Stuart limit cycle system and the chaotic Rössler oscillator as dynamical nodes. During the transition from HSS to IHSSs, the network follows the Turing type symmetry breaking pitchfork or transcritical bifurcation depending upon the system dynamics.

Oscillation death in diffusively coupled oscillators by local repulsive link.

A death of oscillation is reported in a network of coupled synchronized oscillators in the presence of additional repulsive coupling. The repulsive link evolves as an averaging effect of mutual interaction between two neighboring oscillators due to a local fault and the number of repulsive links grows in time when the death scenario emerges. Analytical condition for oscillation death is derived for two coupled Landau-Stuart systems. Numerical results also confirm oscillation death in chaotic systems such as a Sprott system and the Rössler oscillator. We explore the effect in large networks of globally coupled oscillators and find that the number of repulsive links is always fewer than the size of the network.

How to obtain extreme multistability in coupled dynamical systems.

We present a method for designing an appropriate coupling scheme for two dynamical systems in order to realize extreme multistability. We achieve the coexistence of infinitely many attractors for a given set of parameters by using the concept of partial synchronization based on Lyapunov function stability. We show that the method is very general and allows a great flexibility in choosing the coupling. Furthermore, we demonstrate its applicability in different models, such as the Rössler system and a chemical oscillator. Finally we show that extreme multistability is robust with respect to parameter mismatch and, hence, a very general phenomenon in coupled systems.

Engineering generalized synchronization in chaotic oscillators.

We report a method of engineering generalized synchronization (GS) in chaotic oscillators using an open-plus-closed-loop coupling strategy. The coupling is defined in terms of a transformation matrix that maps a chaotic driver onto a response oscillator where the elements of the matrix can be arbitrarily chosen, and thereby allows a precise control of the GS state. We elaborate the scheme with several examples of transformation matrices. The elements of the transformation matrix are chosen as constants, time varying function, state variables of the driver, and state variables of another chaotic oscillator. Numerical results of GS in mismatched Rössler oscillators as well as nonidentical oscillators such as Rössler and Chen oscillators are presented.

[Requirements for product quality of theophylline sustained-release preparations]. / Anforderungen an die Produktqualität von Theophyllin-Retardpräparaten.

In consideration of the narrow therapeutic range and the pharmacology of theophylline (CAS 58-55-9), the pharmaceutic quality of sustained release theophylline preparations should be monitored carefully. During the last few years, the following pharmacokinetic study programme was established as quality criterion to verify the safety and predictability of theophylline concentration-time profiles: bioequivalence from batch to batch, lack of relevant food interaction, lack of relevant gastrointestinal pH or surfactant effects on absorption, pharmacokinetic profile following once-a-day and twice-a-day application, and pharmacokinetics in high-clearance patients. Smooth, predictable and safe concentration-time profiles can be guaranteed exclusively for preparations which fulfill all these quality criteria. Only such high quality formulations allow to reduce or even avoid therapeutic drug monitoring and can be considered as safe and effective drugs for the chronic treatment of asthma.

[The anti-inflammatory action of an oral sustained-release theophylline preparation. Results of a clinical pilot study with low dosages]. / Untersuchungen zur antiinflammatorischen Wirkung eines oralen retardierten Theophyllin-Präparates. Ergebnisse einer Klinischen Pilotstudie mit niedriger Dosierung.

A pilot study in 14 patients with mild asthma was performed to study the anti-inflammatory efficacy of theophylline (CAS 58-55-9). At the start, during and at the end of a 3 months' treatment with oral sustained release theophylline and during 1 week thereafter, the influence on airway hyperreactivity and ECP (eosinophil cationic protein) serum levels was investigated. Airway responsiveness was expressed as the cumulative provocative dose of methacholine necessary to decrease FEV1 by 20% (PD20-FEV1). Data of 8 patients were suitable for evaluation. At a mean predose serum concentration of 6.5 mg/l, theophylline increased the mean PD20-FEV1 for methacholine from 151 micrograms (at start) to 332 micrograms (at the end of medication), and reduced the mean ECP serum concentration from 34.6 to 24.5 micrograms/l. Up to 1 week after theophylline treatment, the improvement of airway hyperreactivity compared to the baseline was maintained, whereas ECP-serum levels tended to increase. Thus, theophylline markedly attenuated airway hyperreactivity in patients with bronchial asthma at "subtherapeutic" serum theophylline concentrations as well as ECP serum concentrations, suggesting the anti-inflammatory efficacy of theophylline. These observations may have therapeutic implications in the treatment of patients with mild asthma. A slight improvement of lung function and dyspnoea, and a reduction of additional beta 2-bronchodilator use was also observed. Two patients only complained of slight nausea, tremor and restlessness.

Changes of interstitial bone thickness with age in men and women.

Mean interstitial bone thickness has been estimated from mean trabecular thickness and mean wall thickness (It.Th = Tb.Th-2*W.Th) with varying results. Some authors found age-related changes of It.Th while others did not. We measured It. Width (It.Wi, 2D) directly, in cancellous iliac crest bone from 23 women aged 20-78 yrs. and 21 men aged 23-74 yrs. At grid-selected sites coupled measurements were done of Tb.Wi and It.Wi, together with W.Wi. It.Wi was defined as the distance between cement lines nearest to the surface at both sides of a trabecula. A thionine stain was used to visualize the cement lines. When the persons studied were divided into two age groups: 20-49 yrs (Group 1) and 50-79 yrs (Group 2) significant but opposite age-related trends were seen both in men and women. Group 1: Men: r = -.68; p < .02; n = 11; Women: r = -.68; p < .02; n = 11. Group 2: Men: r = .79; p < .01; n = 10. Women: r = .59; p < .05; n = 12 (r = coeff. of correlation). Men: It.Wi 63.3 microns (3rd decade [dec.]); 50.8 microns (6th dec.); 67.8 microns (8th dec.). Women: It.Wi 63.7 microns (3rd dec.); 48.3 microns (6th dec.); 63.8 microns (8th dec.). Measured It.Wi values appeared considerably larger than their calculated counterparts (mean delta: 35%). The decline of It.Wi is interpreted as a sign of negative bone balance at the BMU level, leading to thinning of trabeculae, the subsequent increase has to be the result of both declining resorption depth and disappearance of the thinner trabeculae.(ABSTRACT TRUNCATED AT 250 WORDS)

[Does COPD affect bone mineral content?]. / Hat COPD einen Einfluss auf den Knochenmineralgehalt?

In a retrospective study, 85 COPD patients not treated with steroids, and 78 who received steroid therapy, were compared with a control group of normal subjects (n = 126) matched for age and sex. The determination of the bone mineral content (BMC) was carried out with the aid of two-photon absorption measurement performed in the region of the lumbar spine L2-4 and of the neck of the femur. With respect to the distribution of the bone mineral content as a function of sex and pulmonary function reduction, the following results were obtained: 1. There are significant differences between men and women. The BMC is generally lower in women. 2. Significant differences are to be found between the normal subject group and the steroid-free group on the one hand, and the steroid-treated group on the other. The group receiving steroid treatment has appreciably lower BMC values. 3. There are statistically significant correlations between the severity of airway obstruction and the decrease in BMC both in steroid-treated and steroid-free patients.

Radionuclides in detecting active granuloma formation. Gallium-67 scintigraphy and histopathology with autoradiographic findings.

Granuloma formation studies were performed on lungs of guinea pigs sensitized with FCA over 2 to 17 months. Prolonged time of sensitization revealed more granulomatous pulmonary tissue. An intravenous booster of FCA in the animals that had been sensitized for 3 months yielded enhanced granuloma formation within 5 days. The histopathology of these lungs was comparable with that seen in lungs of animals after 17 months of sensitization without booster. Enhanced local proliferation of macrophages, measured by [3H]thymidine incorporation and autoradiography, was seen in the lungs of the animals that had received boosters. Moreover, 67Ga scintigraphy was strongly positive in these animals. Scintigraphy of cell suspensions of pulmonary tissue from these animals showed that 67Ga was predominantly taken up (quantitatively as well as qualitatively) by the alveolar macrophages. Cell suspensions of sarcoidosis patients, prepared in the same way, showed only a low level of 67Ga uptake, one comparable to that of the pulmonary cell suspensions of the sensitized animals that had not received boosters. It is suggested that a negative scintigraphy in patients with chronic pulmonary granulomatous disorders could be (partly) explained by the absence of activated macrophages.

Verruciform xanthoma of the oral mucosa.

The verruciform xanthoma is a rather rare lesion that is mostly confined to the oral mucosa. The clinical picture may vary considerably. The diagnosis is based on the presence of numerous xanthoma cells in the connective tissue papillae. A case of verruciform xanthoma in the floor of the mouth in a 45-year-old woman is presented. The findings reported in the literature are also discussed.