Observation of CR Anisotropy with ARGO-YBJ

The measurement of the anisotropies of cosmic ray arrival direction provides important informations on the propagation mechanisms and on the identification of their sources. In this paper we report the observation of anisotropy regions at different angular scales. In particular, the observation of a possible anisotropy on scales between $\sim$ 10 $^{\circ}$ and $\sim$ 30 $^{\circ}$ suggests the presence of unknown features of the magnetic fields the charged cosmic rays propagate through, as well as potential contributions of nearby sources to the total flux of cosmic rays. Evidence of new weaker few-degree excesses throughout the sky region $195^{\circ}\leq$ R.A. $\leq 315^{\circ}$ is reported for the first time.Comment: Talk given at 12th TAUP Conference 2011, 5-9 September 2011, Munich, German

Optimal adhesion control via cooperative hierarchy, grading, geometries and non-linearity of anchorages

Optimization of dry adhesion in biological organisms is achieved using various strategies at different scale levels. In the past, studies have shown how contact splitting is used effectively by animals such as geckos and insects to increase the total peeling line of contacts and therefore the adhesion force. Also, tapering of contacts or grading of their mechanical properties has been shown to be instrumental in the achievement of improved adhesion efficiency. On a more macroscopic scale, structures such as spider web anchorages exploit hierarchical structure or nonlinear constitutive material properties to improve resilience and to achieve tunability in adhesion/detachment characteristics. Here, we analyse some of these properties and propose some mechanisms for the optimization of adhesion that have thus far been neglected in modelling approaches, and could be potentially exploited for the design of bioinspired adhesives. We consider hierarchical structure, contact tapering, grading of mechanical properties, and their interaction. It emerges that these mechanisms contribute on various size scales to the achievement of optimal adhesive properties through structural complexity and hierarchical organization

RNA silencing can explain chlorotic infection patterns on plant leaves

<p>Abstract</p> <p>Background</p> <p>RNA silencing has been implicated in virus symptom development in plants. One common infection symptom in plants is the formation of chlorotic tissue in leaves. Chlorotic and healthy tissue co-occur on a single leaf and form patterns. It has been shown that virus levels in chlorotic tissue are high, while they are low in healthy tissue. Additionally, the presence of siRNAs is confined to the chlorotic spots and the boundaries between healthy and infected tissue. These results strongly indicate that the interaction between virus growth and RNA silencing plays a role in the formation of infection patterns on leaves. However, how RNA silencing leads to the intricate patterns is not known.</p> <p>Results</p> <p>Here we elucidate the mechanisms leading to infection patterns and the conditions which lead to the various patterns observed. We present a modeling approach in which we combine intra- and inter-cellular dynamics of RNA silencing and viral growth. We observe that, due to the spread of viruses and the RNA silencing response, parts of the tissue become infected while other parts remain healthy. As is observed in experiments high virus levels coincide with high levels of siRNAs, and siRNAs are also present in the boundaries between infected and healthy tissue. We study how single- and double-stranded cleavage by Dicer and amplification by RNA-dependent RNA polymerase can affect the patterns formed.</p> <p>Conclusion</p> <p>This work shows that RNA silencing and virus growth within a cell, and the local spread of virions and siRNAs between cells can explain the heterogeneous spread of virus in leaf tissue, and therewith the observed infection patterns in plants.</p

Organic-Inorganic Nanostructure Architecture via Directly Capping Fullerenes onto Quantum Dots

A new form of fullerene-capped CdSe nanoparticles (PCBA-capped CdSe NPs), using carboxylate ligands with [60] fullerene capping groups that provides an effective synthetic methodology to attach fullerenes noncovalently to CdSe, is presented for usage in nanotechnology and photoelectric fields. Interestingly, either the internal charge transfer or the energy transfer in the hybrid material contributes to photoluminescence (PL) quenching of the CdSe moieties.open2

The dynamics and efficacy of antiviral RNA silencing: A model study

<p>Abstract</p> <p>Background</p> <p>Mathematical modeling is important to provide insight in the complicated pathway of RNA silencing. RNA silencing is an RNA based mechanism that is widely used by eukaryotes to fight viruses, and to control gene expression.</p> <p>Results</p> <p>We here present the first mathematical model that combines viral growth with RNA silencing. The model involves a plus-strand RNA virus that replicates through a double-strand RNA intermediate. The model of the RNA silencing pathway consists of cleavage of viral RNA into siRNA by Dicer, target cleavage of viral RNA via the RISC complex, and a secondary response. We found that, depending on the strength of the silencing response, different viral growth patterns can occur. Silencing can decrease viral growth, cause oscillations, or clear the virus completely. Our model can explain various observed phenomena, even when they seem contradictory at first: the diverse responses to the removal of RNA dependent RNA polymerase; different viral growth curves; and the great diversity in observed siRNA ratios.</p> <p>Conclusion</p> <p>The model presented here is an important step in the understanding of the natural functioning of RNA silencing in viral infections.</p

Caspase Inhibition Blocks Cell Death and Enhances Mitophagy but Fails to Promote T-Cell Lymphoma

Caspase-9 is a component of the apoptosome that mediates cell death following release of cytochrome c from mitochondria. Inhibition of Caspase-9 with a dominant negative construct (Casp9DN) blocks apoptosome function, promotes viability and has been implicated in carcinogenesis. Inhibition of the apoptosome in vitro impairs mitochondrial function and promotes mitophagy. To examine whether inhibition of the apoptosome would enhance mitophagy and promote oncogenesis in vivo, transgenic mice were generated that express Casp9DN in the T cell lineage. The effects of Casp9DN on thymocyte viability, mitophagy and thymic tumor formation were examined. In primary thymocytes, Casp9DN delayed dexamethasone (Dex)-induced cell death, altered mitochondrial structure, and decreased oxidant production. Transmission electron microscopy (TEM) revealed that inhibition of the apoptosome resulted in structurally abnormal mitochondria that in some cases were engulfed by double-membrane structures resembling autophagosomes. Consistent with mitochondria being engulfed by autophagosomes (mitophagy), confocal microscopy showed colocalization of LC3-GFP and mitochondria. However, Casp9DN did not significantly accelerate T-cell lymphoma alone, or in combination with Lck-Bax38/1, or with Beclin 1+/− mice, two tumor-prone strains in which altered mitochondrial function has been implicated in promoting tumor development. In addition, heterozygous disruption of Beclin 1 had no effect on T-cell lymphoma formation in Lck-Bax38/1 mice. Further studies showed that Beclin 1 levels had no effect on Casp9DN-induced loss of mitochondrial function. These results demonstrate that neither inhibition of apoptosome function nor Beclin 1 haploinsufficiency accelerate T-cell lymphoma development in mice

Identification of Human Fibroblast Cell Lines as a Feeder Layer for Human Corneal Epithelial Regeneration

There is a great interest in using epithelium generated in vitro for tissue bioengineering. Mouse 3T3 fibroblasts have been used as a feeder layer to cultivate human epithelia including corneal epithelial cells for more than 3 decades. To avoid the use of xeno-components, we evaluated human fibroblasts as an alternative feeder supporting human corneal epithelial regeneration. Five human fibroblast cell lines were used for evaluation with mouse 3T3 fibroblasts as a control. Human epithelial cells isolated from fresh corneal limbal tissue were seeded on these feeders. Colony forming efficiency (CFE) and cell growth capacity were evaluated on days 5–14. The phenotype of the regenerated epithelia was evaluated by morphology and immunostaining with epithelial markers. cDNA microarray was used to analyze the gene expression profile of the supportive human fibroblasts. Among 5 strains of human fibroblasts evaluated, two newborn foreskin fibroblast cell lines, Hs68 and CCD1112Sk, were identified to strongly support human corneal epithelial growth. Tested for 10 passages, these fibroblasts continually showed a comparative efficiency to the 3T3 feeder layer for CFE and growth capacity of human corneal epithelial cells. Limbal epithelial cells seeded at 1×104 in a 35-mm dish (9.6 cm2) grew to confluence (about 1.87–2.41×106 cells) in 12–14 days, representing 187–241 fold expansion with over 7–8 doublings on these human feeders. The regenerated epithelia expressed K3, K12, connexin 43, p63, EGFR and integrin β1, resembling the phenotype of human corneal epithelium. DNA microarray revealed 3 up-regulated and 10 down-regulated genes, which may be involved in the functions of human fibroblast feeders. These findings demonstrate that commercial human fibroblast cell lines support human corneal epithelial regeneration, and have potential use in tissue bioengineering for corneal reconstruction

Occurrence of Regulated and Emerging Iodinated DBPs in the Shanghai Drinking Water

10.1371/journal.pone.0059677PLoS ONE83

Constitutively elevated levels of SOCS1 suppress innate responses in DF-1 immortalised chicken fibroblast cells.

The spontaneously immortalised DF-1 cell line is rapidly replacing its progenitor primary chicken embryo fibroblasts (CEFs) for studies on avian viruses such as avian influenza but no comprehensive study has as yet been reported comparing their innate immunity phenotypes. We conducted microarray analyses of DF-1 and CEFs, under both normal and stimulated conditions using chicken interferon-α (chIFN-α) and the attenuated infectious bursal disease virus vaccine strain PBG98. We found that DF-1 have an attenuated innate response compared to CEFs. Basal expression levels of Suppressor of Cytokine Signalling 1 (chSOCS1), a negative regulator of cytokine signalling in mammals, are 16-fold higher in DF-1 than in CEFs. The chSOCS1 “SOCS box” domain (which in mammals, interacts with an E3 ubiquitin ligase complex) is not essential for the inhibition of cytokine-induced JAK/STAT signalling activation in DF-1. Overexpression of SOCS1 in chIFN-α-stimulated DF-1 led to a relative decrease in expression of interferon-stimulated genes (ISGs; MX1 and IFIT5) and increased viral yield in response to PBG98 infection. Conversely, knockdown of SOCS1 enhanced induction of ISGs and reduced viral yield in chIFN-α-stimulated DF-1. Consequently, SOCS1 reduces induction of the IFN signalling pathway in chicken cells and can potentiate virus replication