Robust Finite-time stability of homogeneous systems with respect tomultiplicative disturbances

International audienceLyapunov characterizations of output finite-time stability are presented for the system $x' = f (x), y = h(x)$ which is locally Lipschitz continuous out of the set $Y = {x ∈ R n : h(x) = 0}$ and continuous on $R^n$. The definitions are given in the form of $K$ and $KL$ functions. Necessary and sufficient conditions for output finite-time stability are given using Lyapunov functions. The theoretical results are supported by numerical examples

Growth of quantum dot coated core-shell anisotropic nanowires for improved thermal and electronic transport

Anisotropic nanowires are promising candidates for electronic thermal management due to their unique electrical and thermal properties.However, eco-friendly solution-processed nanomaterials with an elaborate morphology and microstructure for modulating thermal andcharge transfer are still a considerable challenge. Herein, we present a simple but effective approach for synthesizing pseudo core-shell nano-wires through quantum dot (QD)-like nanostructure coating (p-NW@QD) to generate exceptional electron-phonon transport properties.With the assistance of diphenyl ether as a coordination solvent, high crystallinity lead sulfide NWs can be fabricated with a large aspect ratiotogether with uniform QD coating. Thisp-NW@QD exhibits high electronic mobility (30.65 cm2/Vs) as well as a diameter independent lowthermal conductivity (1.5361 W/m K). Direct charge/heat carrier flow measurements and computational simulations demonstrate that theunusual electrical and thermal transport phenomenon is strongly dependent on the fast charge transport through the QD shell, and a slowphonon migration across the Umklapp process dominated NW cores. These findings indicate a significant step toward colloidal synthesisnanostructures for future high-performance nanoelectronics and thermal energy devices

Red green blue emissive lead sulfide quantum dots: heterogeneous synthesis and applications.

Visible emission colloidal quantum dots (QDs) have shown promise in optical and optoelectronic applications. These QDs are typically composed of relatively expensive elements in the form of indium, cadmium, and gallium since alternative candidate materials exhibiting similar properties are yet to be realized. Herein, for the first time, we report red green blue (RGB) photoluminescences with quantum yields of 18% from earth-abundant lead sulfide (PbS) QDs. The visible emissive property is mainly attributed to a high degree of crystallinity even for the extremely small QD sizes (1-3 nm), which is realized by employing a heterogeneous reaction methodology at high growth temperatures (>170 °C). We demonstrate that the proposed heterogeneous synthetic method can be extended to the synthesis of other metal chalcogenide QDs, such as zinc sulfide and zinc selenide, which are promising for future industrial applications. More importantly, benefiting from the enlarged band gaps, the as-prepared PbS solar cells show an impressive open circuit voltage (∼0.8 V) beyond that reported to date

Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivation.

Colloidal quantum dots (CQDs) are extremely promising as photovoltaic materials. In particular, the tunability of their electronic band gap and cost effective synthetic procedures allow for the versatile fabrication of solar energy harvesting cells, resulting in optimal device performance. However, one of the main challenges in developing high performance quantum dot solar cells (QDSCs) is the improvement of the photo-generated charge transport and collection, which is mainly hindered by imperfect surface functionalization, such as the presence of surface electronic trap sites and the initial bulky surface ligands. Therefore, for these reasons, finding effective methods to efficiently decorate the surface of the as-prepared CQDs with new short molecular length chemical structures so as to enhance the performance of QDSCs is highly desirable. Here, we suggest employing hybrid halide ions along with the shortest heterocyclic molecule as a robust passivation structure to eliminate surface trap sites while decreasing the charge trapping dynamics and increasing the charge extraction efficiency in CQD active layers. This hybrid ligand treatment shows a better coordination with Pb atoms within the crystal, resulting in low trap sites and a near perfect removal of the pristine initial bulky ligands, thereby achieving better conductivity and film structure. Compared to halide ion-only treated cells, solar cells fabricated through this hybrid passivation method show an increase in the power conversion efficiency from 5.3% for the halide ion-treated cells to 6.8% for the hybrid-treated solar cells

Endoscopic Therapy of Colonic Liver Flexure Mucocele

Colorectal mucoceles usually arise in the appendix, and colonic disease is very rare. We report the first case of a mucocele of the colonic liver flexure that was treated successfully with endoscopy. A 36-year-old man was admitted to our hospital because of abdominal distension persisting for 3 days. Colonoscopic examination revealed a round polyp in the hepatic flexure, and we performed hot snare polypectomy with argon plasma coagulation. Histologically, the polypectomy specimen was confirmed to be a mucocele, with no neoplastic changes. Follow-up examinations at 6 and 12 months showed no evidence of recurrence

Mining and Characterization of Sequence Tagged Microsatellites from the Brown Planthopper Nilaparvata lugens

The brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is an important pest of rice. To better understand the migration pattern and population structure of the Chinese populations of N. lugens, we developed and characterized 12 polymorphic microsatellites from the expressed sequence tags database of N. lugens. The occurrence of these simple sequence repeats was assessed in three populations collected from three provinces of China. The number of alleles per locus ranged from 3 to 13 with an average of 6.5 alleles per locus. The mean observed heterozygosity of the three populations ranged from 0.051 to 0.772 and the expected heterozygosity ranged from 0.074 to 0.766. The sequences of the 12 markers were highly variable. The polymorphism information content of the 12 markers was high and ranged from 0.074 to 0.807 (mean = 0.503). Sequencing of microsatellite alleles revealed that the fragment length differences were mainly due to the variation of the repeat motif. Significant genetic differentiation was detected among the three N. lugens populations as the Fst ranged from 0.034 to 0.273. Principle coordinates analysis also revealed significant genetic differentiation between populations of different years. We conclude that these microsatellite markers will be a powerful tools to study the migration routine of the N. lugens

Two new ArrayTrack libraries for personalized biomedical research

<p>Abstract</p> <p>Background</p> <p>Recent advances in high-throughput genotyping technology are paving the way for research in personalized medicine and nutrition. However, most of the genetic markers identified from association studies account for a small contribution to the total risk/benefit of the studied phenotypic trait. Testing whether the candidate genes identified by association studies are causal is critically important to the development of personalized medicine and nutrition. An efficient data mining strategy and a set of sophisticated tools are necessary to help better understand and utilize the findings from genetic association studies. </p> <p>Description</p> <p>SNP (single nucleotide polymorphism) and QTL (quantitative trait locus) libraries were constructed and incorporated into ArrayTrack, with user-friendly interfaces and powerful search features. Data from several public repositories were collected in the SNP and QTL libraries and connected to other domain libraries (genes, proteins, metabolites, and pathways) in ArrayTrack. Linking the data sets within ArrayTrack allows searching of SNP and QTL data as well as their relationships to other biological molecules. The SNP library includes approximately 15 million human SNPs and their annotations, while the QTL library contains publically available QTLs identified in mouse, rat, and human. The QTL library was developed for finding the overlap between the map position of a candidate or metabolic gene and QTLs from these species. Two use cases were included to demonstrate the utility of these tools. The SNP and QTL libraries are freely available to the public through ArrayTrack at <url>http://www.fda.gov/ArrayTrack</url>. </p> <p>Conclusions</p> <p>These libraries developed in ArrayTrack contain comprehensive information on SNPs and QTLs and are further cross-linked to other libraries. Connecting domain specific knowledge is a cornerstone of systems biology strategies and allows for a better understanding of the genetic and biological context of the findings from genetic association studies. </p

The effects of degree correlations on network topologies and robustness

Complex networks have been applied to model numerous interactive nonlinear systems in the real world. Knowledge about network topology is crucial for understanding the function, performance and evolution of complex systems. In the last few years, many network metrics and models have been proposed to illuminate the network topology, dynamics and evolution. Since these network metrics and models derive from a wide range of studies, a systematic study is required to investigate the correlations between them. The present paper explores the effect of degree correlation on the other network metrics through studying an ensemble of graphs where the degree sequence (set of degrees) is fixed. We show that to some extent, the characteristic path length, clustering coefficient, modular extent and robustness of networks are directly influenced by the degree correlation.Comment: 13 pages, 6 figure

Network adaptation improves temporal representation of naturalistic stimuli in drosophila eye: II Mechanisms

Retinal networks must adapt constantly to best present the ever changing visual world to the brain. Here we test the hypothesis that adaptation is a result of different mechanisms at several synaptic connections within the network. In a companion paper (Part I), we showed that adaptation in the photoreceptors (R1-R6) and large monopolar cells (LMC) of the Drosophila eye improves sensitivity to under-represented signals in seconds by enhancing both the amplitude and frequency distribution of LMCs' voltage responses to repeated naturalistic contrast series. In this paper, we show that such adaptation needs both the light-mediated conductance and feedback-mediated synaptic conductance. A faulty feedforward pathway in histamine receptor mutant flies speeds up the LMC output, mimicking extreme light adaptation. A faulty feedback pathway from L2 LMCs to photoreceptors slows down the LMC output, mimicking dark adaptation. These results underline the importance of network adaptation for efficient coding, and as a mechanism for selectively regulating the size and speed of signals in neurons. We suggest that concert action of many different mechanisms and neural connections are responsible for adaptation to visual stimuli. Further, our results demonstrate the need for detailed circuit reconstructions like that of the Drosophila lamina, to understand how networks process information

The Functional DRD3 Ser9Gly Polymorphism (rs6280) Is Pleiotropic, Affecting Reward as Well as Movement

Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis