Block oriented model order reduction of interconnected systems

Unintended and parasitic coupling effects are becoming more relevant in currently designed, small-scale/highfrequency RFICs. Electromagnetic (EM) based procedures must be used to generate accurate models for proper verification of system behaviour. But these EM methodologies may take advantage of structural sub-system organization as well as information inherent to the IC physical layout, to improve their efficiency. Model order reduction techniques, required for fast and accurate evaluation and simulation of such models, must address and may benefit from the provided hierarchical information. System-based interconnection techniques can handle some of these situations, but suffer from some drawbacks when applied to complete EM models. We will present an alternative methodology, based on similar principles, that overcomes the limitations of such approaches. The procedure, based on structure-preserving model order reduction techniques, is proved to be a generalization of the interconnected system based framework. Further improvements that allow a trade off between global error and block size, and thus allow a better control on the reduction, will be also presented

Eficacia y seguridad del adhesivo tisular Tisuacryl en el cierre de la piel de la episiotomía

Se realizó un ensayo clínico fase III, en el Hospital Docente Materno Infantil 10 de Octubre, de Ciudad de La Habana, Cuba, entre julio de 1999 y marzo del 2000, con el objetivo de evaluar la eficacia y seguridad del adhesivo tisular Tisuacryl en el cierre de la piel de la episiotomía. Cada grupo constó de 300 pacientes, de acuerdo a los criterios de inclusión establecidos para el ensayo. En el grupo estudio se presentaron menos molestias en la episiorrafia (95.6 %) que en el grupo control (56.3 %) a los 30 minutos post parto, así como al tercer día posterior al nacimiento (97.6 % vs. 61.3 %). Al séptimo día, los resultados en el afrontamiento, estética y molestias en la herida fueron significativamente mejores con el adhesivo tisular evaluado. Los riesgos relativos de resultados adversos al séptimo día posterior al parto fueron 3.2 veces mayores en relación con afrontamiento y 2.9 veces con la estética no satisfactorias cuando se utilizó catgut cromado al comparar con el Tisuacryl. Para las molestias en la episiorrafia, el riesgo relativo se elevó a 24.2, todos con diferencias estadísticas significativas. Se concluye que el uso del adhesivo tisular Tisuacryl para el cierre de la piel en la episiotomía tiene menor probabilidad de afrontamiento y estética de la herida no satisfactoria y de menor sensación dolorosa en la herida quirúrgica que el catgut cromado.Peer Reviewe

Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions

Background Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Results Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. Conclusions The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions

Alterations in PGC1[alfa] expression levels are involved in colorectal cancer risk: a qualitative systematic review

Background: Colorectal cancer (CRC) is a major global public health problem and the second leading cause of cancer-related death. Mitochondrial dysfunction has long been suspected to be involved in this type of tumorigenesis, as supported by an accumulating body of research evidence. However, little is known about how mitochondrial alterations contribute to tumorigenesis. Mitochondrial biogenesis is a fundamental cellular process required to maintain functional mitochondria and as an adaptive mechanism in response to changing energy requirements. Mitochondrial biogenesis is regulated by peroxisome proliferator-activated receptor gamma coactivator 1-? (PPARGC1A or PGC1?). In this paper, we report a systematic review to summarize current evidence on the role of PGC1? in the initiation and progression of CRC. The aim is to provide a basis for more comprehensive research. Methods: The literature search, data extraction and quality assessment were performed according to the document Guidance on the Conduct of Narrative Synthesis in Systematic Reviews and the PRISMA declaration. Results: The studies included in this review aimed to evaluate whether increased or decreased PGC1? expression affects the development of CRC. Each article proposes a possible molecular mechanism of action and we create two concept maps. Conclusion: Our systematic review indicates that altered expression of PGC1? modifies CRC risk. Most studies showed that overexpression of this gene increases CRC risk, while some studies indicated that lower than normal expression levels could increase CRC risk. Thus, various authors propose PGC1? as a good candidate molecular target for cancer therapy. Reducing expression of this gene could help to reduce risk or progression of CRC

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Parametric structure-preserving model order reduction

Analysis and verification environments for next- generation nano-scale RFIC designs must be able to cope with increasing design complexity and to account for new effects, such as process variations and Electromagnetic (EM) couplings. Designed-in passives, substrate, interconnect and devices can no longer be treated in isolation as the interactions between them are becoming more relevant in the behavior of the complete system. At the same time variations in process parameters lead to small changes in the device characteristics that may directly affect system performance. These two effects, however, can not be treated separately as the process variations that modify the physical parameters of the devices also affect those same EM couplings. Accurately capturing the effects of process variations as well as the relevant EM coupling effects requires detailed models that become very expensive to simulate. Reduction techniques able to handle parametric descriptions of linear systems are necessary in order to obtain better simulation performance. In this work Model Order Reduction techniques able to handle parametric system descriptions are presented. Such techniques are based on Structure-Preserving formulations that are able to exploit the hierarchical system representation of designed- in blocks, substrate and interconnect, in order to obtain more efficient simulation models

Parametric structure-preserving model order reduction

Analysis and verification environments for next-generation nano-scale RFIC designs must be able to cope with increasing design complexity and to account for new effects, such as process variations and Electromagnetic (EM) couplings. Designed-in passives, substrate, interconnect and devices can no longer be treated in isolation as the interactions between them are becoming more relevant to the behavior of the complete system. At the same time variations in process parameters lead to small changes in the device characteristics that may directly affect system performance. These two effects, however, cannot be treated separately as the process variations that modify the physical parameters of the devices also affect those same EM couplings. Accurately capturing the effects of process variations as well as the relevant EM coupling effects requires detailed models that become very expensive to simulate. Reduction techniques able to handle parametric descriptions of linear systems are necessary in order to obtain better simulation performance. In this work we discuss parametric Model Order Reduction techniques based on Structure-Preserving formulations that are able to exploit the hierarchical system representation of designed-in blocks, substrate and interconnect, in order to obtain more efficient simulation models

Order reduction techniques for coupled multi-domain electromagnetic based models

This work presents a comprehensive flow able to efficiently generate reduced order models for realistic, hierarchy aware, Electromagnetic (EM) based models. Knowledge of the structure of the problem is explicitly exploited using domain partitioning and novel electromagnetic connector modeling techniques to generate a hierarchically coupled representation. This enables the efficient use of structure preserving block model order reduction techniques to generate block-wise compressed models that satisfy overall requirements, and provide cheap evaluation and simulation accurate approximations of the complete EM behaviour