Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation

Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100-1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H(2)SO(4)-H(2)O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.     

Revision of the West Palaearctic species of Rhoptromeris Förster, 1869 (Hymenoptera: Figitidae: Eucoilinae)

The West Palearctic species of Rhoptromeris are revised. A total of 11 species are recognised as valid in this region, including four newly described species: Rhoptromeris dichromata sp. nov., Rhoptromeris koponeni sp. nov., Rhoptromeris leptocornis sp. nov. and Rhoptromeris macaronesiensis sp. nov. Eucoila luteicornis Ionescu, 1959 is synonymised with Rhoptromeris heptoma (Hartig, 1840) syn. nov. A checklist of the Holarctic Rhoptromeris is presented and an identification key to the West Palearctic species is provided. www.zoobank.org/urn:lsid:zoobank.org:pub:8164332C-93E2-4E3F-A408-F5FF5DFB366E     

Increased migration of olfactory ensheathing cells secreting the Nogo receptor ectodomain over inhibitory substrates and lesioned spinal cord

Olfactory ensheathing cell (OEC) transplantation emerged some years ago as a promising therapeutic strategy to repair injured spinal cord. However, inhibitory molecules are present for long periods of time in lesioned spinal cord, inhibiting both OEC migration and axonal regrowth. Two families of these molecules, chondroitin sulphate proteoglycans (CSPG) and myelin-derived inhibitors (MAIs), are able to trigger inhibitory responses in lesioned axons. Mounting evidence suggests that OEC migration is inhibited by myelin. Here we demonstrate that OEC migration is largely inhibited by CSPGs and that inhibition can be overcome by the bacterial enzyme Chondroitinase ABC. In parallel, we have generated a stable OEC cell line overexpressing the Nogo receptor (NgR) ectodomain to reduce MAI-associated inhibition in vitro and in vivo. Results indicate that engineered cells migrate longer distances than unmodified OECs over myelin or oligodendrocyte-myelin glycoprotein (OMgp)-coated substrates. In addition, they also show improved migration in lesioned spinal cord. Our results provide new insights toward the improvement of the mechanisms of action and optimization of OEC-based cell therapy for spinal cord lesion.     

Kuhn and the genesis of the "new historiography of science"

In this paper I identify a tension between the two sets of works by Kuhn regarding the genesis of the "new historiography of science". In the first, it could be said that the change from the traditional to the new historiography is strictly endogenous (referring to internal causes or reasons). In the second, the change is predominantly exogenous. To address this question, I draw on a text that is considered to be less important among Kuhn's works, but which, as shall be argued, allows some contact between Kuhn's two approaches via Koyré. I seek to point out and differentiate the roles of Koyré and Kuhn--from Kuhn's point of view--in the development of the historiography of science and, as a complement, present some reflections regarding the justification of the new historiography.     

Can We Predict the Financial Markets Based on Google's Search Queries?

We look into the interaction of Google's search queries and several aspects of international equity markets. Using a novel methodology for selecting words and a vector autoregressive modeling approach, we study whether the search queries of finance‐related words can have an impact on returns, volatility of returns and traded volume in four different English‐speaking countries. We identify several words whose search frequency is associated with changes in the dependent variables. In particular, we find that increases in search queries including the word stock predict increased volatility and decreased index returns over the next week. On top of that, we investigate the performance of a market‐timing strategy based on the search frequency of this word and benchmark it against random words from the Word‐Net database and a naive buy‐and‐hold strategy. The results of this empirical application are positive and particularly stronger during the global crisis of 2009. Copyright © 2016 John Wiley & Sons, Ltd.     

Toxin bioportides: exploring toxin biological activity and multifunctionality

Toxins have been shown to have many biological functions and to constitute a rich source of drugs and biotechnological tools. We focus on toxins that not only have a specific activity, but also contain residues responsible for transmembrane penetration, which can be considered bioportides—a class of cell-penetrating peptides that are also intrinsically bioactive. Bioportides are potential tools in pharmacology and biotechnology as they help deliver substances and nanoparticles to intracellular targets. Bioportides characterized so far are peptides derived from human proteins, such as cytochrome c (CYCS), calcitonin receptor (camptide), and endothelial nitric oxide synthase (nosangiotide). However, toxins are usually disregarded as potential bioportides. In this review, we discuss the inclusion of some toxins and molecules derived thereof as a new class of bioportides based on structure activity relationship, minimization, and biological activity studies. The comparative analysis of the amino acid residue composition of toxin-derived bioportides and their short molecular variants is an innovative analytical strategy which allows us to understand natural toxin multifunctionality in vivo and plan novel pharmacological and biotechnological products. Furthermore, we discuss how many bioportide toxins have a rigid structure with amphiphilic properties important for both cell penetration and bioactivity.     

The PDZ2 domain of zonula occludens-1 and -2 is a phosphoinositide binding domain

Zonula occludens proteins (ZO) are postsynaptic density protein-95 discs large-zonula occludens (PDZ) domain-containing proteins that play a fundamental role in the assembly of tight junctions and establishment of cell polarity. Here, we show that the second PDZ domain of ZO-1 and ZO-2 binds phosphoinositides (PtdInsP) and we identified critical residues involved in the interaction. Furthermore, peptide and PtdInsP binding of ZO PDZ2 domains are mutually exclusive. Although lipid binding does not seem to be required for plasma membrane localisation of ZO-1, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P ₂) binding to the PDZ2 domain of ZO-2 regulates ZO-2 recruitment to nuclear speckles. Knockdown of ZO-2 expression disrupts speckle morphology, indicating that ZO-2 might play an active role in formation and stabilisation of these subnuclear structures. This study shows for the first time that ZO isoforms bind PtdInsPs and offers an alternative regulatory mechanism for the formation and stabilisation of protein complexes in the nucleus.     

Red blood cells carry out T cell growth and survival bioactivities that are sensitive to cyclosporine A

Red blood cells (RBC) have emerged as a novel regulatory cell type endowed with bioactivities toward activated human T cells. Herein we show that the RBC bioactivities act on intracellular pathways initiated by T cell receptor (TCR)-dependent and -independent stimuli, including IL-2, IL-15, and the mixture of phorbol dibutyrate and ionomycin. The RBC bioactivities preserve the antioxidant status and are capable of rescuing activated T cells from cell death induced by serum deprivation. They are not mediated by glycosylphosphatidylinositol-linked receptors or sialic acids, and kinetic studies revealed that they hasten the entrance into the cell cycle. By using cyclosporine A (CsA) and rapamycin (Rapa) we show that the RBC bioactivities are calcineurin-dependent. Thus, treatment of T cells with CsA, but not Rapa, impaired RBC bioactivities, and preincubation of RBC with CsA completely abolished their bioactivities. We have demonstrated that RBC carry out bioactivities that are sensitive to CsA.