Robust stability and stabilization for singular systems with state delay and parameter uncertainty

This note considers the problems of robust stability and stabilization for uncertain continuous singular systems with state delay. The parametric uncertainty is assumed to be norm bounded. The purpose of the robust stability problem is to give conditions such that the uncertain singular system is regular, impulse free, and stable for all admissible uncertainties, while the purpose of robust stabilization is to design a state feedback control law such that the resulting closed-loop system is robustly stable. These problems are solved via the notions of generalized quadratic stability and generalized quadratic stabilization, respectively. Necessary and sufficient conditions for generalized quadratic stability and generalized quadratic stabilization are derived. A strict linear matrix inequality (LMI) design approach is developed. An explicit expression for the desired robust state feedback control law is also given. Finally, a numerical example is provided to demonstrate the application of the proposed method.published_or_final_versio

Early Primary Percutaneous Coronary Intervention in Patients with ST-segment Elevation Acute Myocardial Infarction from the Cluj Area

Background: The seriousness of acute myocardial infarction (AMI) and the importance of its early detection and intervention are well known. Rapid reperfusion of the infarct area positively influences the immediate and long-term prognosis of patients with ST-segment elevation AMI. Material and method: Patients with acute myocardial infarction who underwent primary percutaneous transluminal coronary angioplasty (during the first 12 hours after the onset of chest pain) in the cardiac catheterization laboratory of the Cluj-Napoca “Nicolae Stancioiu” Heart Institute between November 2008 and February 2010 were followed prospectively in order to measure time-to-treatment intervals. Results: Our sample of 321 AMI patients included mostly males (73.8% of cases, 95% CI: 68.6-78.5; p<0.001) and patients from the urban area (67.6% of cases, 95% CI: 62.1-72.6; p<0.001) aged between 50 and 79 years. Total ischemia time (from onset of precordial pain to primary angioplasty) was 338.9 minutes on average (between 100 and 720 minutes); ambulance waiting time was 22.1 minutes (3-150 minutes); transport to first hospital took 49.9 minutes (5-276 minutes) while transport to a cardiology hospital averaged 247 minutes from the onset of pain (maximum 660 minutes). The door-to-balloon time was 91.9 minutes while early intervention was possible in 27.4% (95% CI: 22.7-32.7%) of AMI cases. Conclusions: Time-to-treatment intervals allowed early reperfusion in only one third of AMI patients due to lack of access to specialised cardiology hospitals in rural areas and inconsistencies regarding the attitude towards AMI cases across counties

Surface morphology of titanium nitride thin films synthesized by DC reactive magnetron sputtering

In this paper the influence of temperature on the 3-D surface morphology of titanium nitride (TiN) thin films synthesized by DC reactive magnetron sputtering has been analyzed. The 3-D morphology variation of TiN thin films grown on p-type Si (100) wafers was investigated at four different deposition temperatures (473 K, 573 K, 673 K, 773 K) in order to evaluate the relation among the 3-D micro-textured surfaces. The 3-D surface morphology of TiN thin films was characterized by means of atomic force microscopy (AFM) and fractal analysis applied to the AFM data. The 3-D surface morphology revealed the fractal geometry of TiN thin films at nanometer scale. The global scale properties of 3-D surface geometry were quantitatively estimated using the fractal dimensions D, determined by the morphological envelopes method. The fractal dimension D increased with the substrate temperature variation from 2.36 (at 473 K) to 2.66 (at 673 K) and then decreased to 2.33 (at 773 K). The fractal analysis in correlation with the averaged power spectral density (surface) yielded better quantitative results of morphological changes in the TiN thin films caused by substrate temperature variations, which were more precise, detailed, coherent and reproducible. It can be inferred that fractal analysis can be easily applied for the investigation of morphology evolution of different film/substrate interface phases obtained using different thin-film technologies

Evaluation of the combined therapeutic effect of methylprednisolone and cerebrolysin in traumatic medullar lesion

Objectives: The pharmacological effects of Methylprednisolone and Cerebrolysin have been extensively debated, but from our knowledge there are no studies to evaluate the association of these two drugs in spinal cord injury (SCI).Methods: Twenty-four Wistar rats underwent traumatic spinal cord injury by using clip-compression model. The animals were divided into four groups: group I received Methylprednisolone (MP); group II was injected with Cerebrolysin (C); group III received Methylprednisolone together with Cerebrolysin (MP+C); in the control group we have performed only decompression. The motor recovery of the animals was evaluated using the Ferguson et al. modification of the BBB scale. After ten days the rats were sacrificed.&nbsp;Results: The study demonstrated that the MP + C group presented the most notable recovery of the motor function, but no statistically significant (p&gt;0,05). The first and the second group also presented better results than the fourth group, but the enhanced recovery of those group relative to control group was not statistically significant (p&gt;0,05)&nbsp;Conclusion: The combination of MP and Cerebrolysin in experimental conditions seems to have promising results, but more experimental and clinical studies are necessary to evaluate the real benefit for SCI patients

First Evidence of Reproductive Adaptation to “Island Effect” of a Dwarf Cretaceous Romanian Titanosaur, with Embryonic Integument In Ovo

<div><h3>Background</h3><p>The Cretaceous vertebrate assemblages of Romania are famous for geographically endemic dwarfed dinosaur taxa. We report the first complete egg clutches of a dwarf lithostrotian titanosaur, from Toteşti, Romania, and its reproductive adaptation to the “island effect”.</p> <h3>Methodology/Findings</h3><p>The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian Sânpetru Formation, Toteşti. The occurrence of 11 homogenous clutches in successive strata suggests philopatry by the same dinosaur species, which laid clutches averaging four ∼12 cm diameters eggs. The eggs and eggshells display numerous characters shared with the positively identified material from egg-bearing level 4 of the Auca Mahuevo (Patagonia, Argentina) nemegtosaurid lithostrotian nesting site. Microscopic embryonic integument with bacterial evidences was recovered in one egg. The millimeter-size embryonic integument displays micron size dermal papillae implying an early embryological stage at the time of death, likely corresponding to early organogenesis before the skeleton formation.</p> <h3>Conclusions/Significance</h3><p>The shared oological characters between the Haţeg specimens and their mainland relatives suggest a highly conservative reproductive template, while the nest decrease in egg numbers per clutch may reflect an adaptive trait to a smaller body size due to the “island effect”. The combined presence of the lithostrotian egg and its embryo in the Early Cretaceous Gobi coupled with the oological similarities between the Haţeg and Auca Mahuevo oological material evidence that several titanosaur species migrated from Gondwana through the Haţeg Island before or during the Aptian/Albian. It also suggests that this island might have had episodic land bridges with the rest of the European archipelago and Asia deep into the Cretaceous.</p> </div

Phage-centric ecological interactions in aquatic ecosystems revealed through ultra-deep metagenomics

The persistent inertia in the ability to culture environmentally abundant microbes from aquatic ecosystems represents an obstacle in disentangling the complex web of ecological interactions spun by a diverse assortment of participants (pro- and eukaryotes and their viruses). In aquatic microbial communities, the numerically most abundant actors, the viruses, remain the most elusive, and especially in freshwaters their identities and ecology remain unknown. Here, using ultra-deep metagenomic sequencing from pelagic freshwater habitats, we recovered complete genomes of > 2000 phages, including small “miniphages” and large “megaphages” infecting iconic freshwater prokaryotic lineages. For instance, abundant freshwater Actinobacteria support infection by a very broad size range of phages (13–200 Kb). We describe many phages encoding genes that likely afford protection to their host from reactive oxygen species (ROS) in the aquatic environment and in the oxidative burst in protist phagolysosomes (phage-mediated ROS defense). Spatiotemporal abundance analyses of phage genomes revealed evanescence as the primary dynamic in upper water layers, where they displayed short-lived existences. In contrast, persistence was characteristic for the deeper layers where many identical phage genomes were recovered repeatedly. Phage and host abundances corresponded closely, with distinct populations displaying preferential distributions in different seasons and depths, closely mimicking overall stratification and mixis

Multiscale surface texture and fractal analysis of straight bevel gears finished by PECH and PECF process

The present work was conducted to provide insights for an in-depth understanding of the straight bevel gears finished by pulsed-electrochemical-honing (PECH) and pulsed-electrochemical-finishing (PECF), using multi-scale surface texture and fractal analysis in order to give manufacturers a competitive edge when improving their tools. Unfinished bevel gears and bevel gears finished by PECF and PECH were analyzed on their surface texture characteristics and material properties. Surface characteristics of 20MnCr5 alloy steel gears were evaluated by computing four locations on regions of each sample. Field emission scanning electron microscopy (FESEM) was applied for surface material characterization. It was found that it can be discriminated between the PECF and PECH-finished bevel gears surface regions of samples and unfinished samples, using area-scale analysis and surface texture characteristics. The surface micro-morphology results can be applied in studies about improving the lifetime of tools and for mathematical modeling of lubrication processes between tool and workpiece