16 research outputs found
Capital structure determinants and the new High-Tech firms: The critical distinction between fixed and random effects through a static panel data investigation
The aim of our research is to study the association between observed leverage and a set of explanatory variables, using panel data analysis to establish the determinants of a time varying optimal capital structure from new high-tech firms over the period 1998-2002, and to explore whether the main theories of firm financing (Trade-Off Theory and Pecking Order Theory) can explain the capital structure of these firms. We consider the static models, introducing the critical distinction between fixed and random effects.
This is the first time the scope of studying the determinants of the capital structure has been extended to new high-tech firms with the use of many techniques of panel data.
Considering the results of the most powerful estimation (WG) as our reference, the empirical evidences obtained are stable and similar to those documented in the previous empirical researches.
Confirming the pecking order model but contradicting the trade-off model, we find that more profitable firms use less leverage. We also find that large companies tend to use more debt than smaller companies, and that firms which have high operating risk can lower the volatility of the net profit by reducing the level of debt.
Leverage is also closely related to tangibility of assets and to the ratio of non-debt tax shield
The History of the Remains of the Roman Emperor, Julian the Apostate
Julian (Flavius Claudius Iulianus), called the Apostate, Roman emperor in the years 361–363, was one of the most intriguing rulers. From antiquity to the present day he invariably aroused great interest, both during his life and after his death. He was a just emperor, a wise commander, and a very talented writer. On 26 June 363 Julian the Apostate was mortally wounded during a battle with the Persians. He spent the last moments of his life discussing with philosophers Priskus and Maksimus the nobility of the soul, as we learn from the historian Ammianus Marcellinus. The ruler then showed, perhaps too ostentatiously, his greatest passion: love of virtue and fame. Julian the Apostate died at the age of thirty-two after only twenty months of his rule. Julian’s body, as Gregory of Nazianzus recalls, was transported from Nisibis to Tarsus in Cilicia, which took fifteen days. The subjects greeted the arrival of the body with a mournful lament or contemptuous insults, as the Father of the Church adds. Julian wanted to rest after death in Tarsus, in a mausoleum next to a small temple on the banks of the Cydnus River. Then, at an unspecified time, as the chronicler Zonaras recalls, the body of Emperor Julian the Apostate was transferred to Constantinople and buried in the Church of the Holy Apostles. Constantine Porphyrogenitus in his collection On the ceremonies of the imperial court (book II, chapter 42) mentions the grave of Julian. Today one of the porphyry sarcophagi, kept in the Archaeological Museum in Istanbul, is sometimes considered the Julian sarcophagus. The theme of this article is an attempt to determine the posthumous fate of Emperor Julian the Apostate’s body, i.e. when and in what circumstances it was transferred to Constantinople
Role of endocytotic uptake routes in impacting the ROS-related toxicity of silver nanoparticles to Mytilus galloprovincialis: a redox proteomic investigation
Oxidative stress is often implicated in nanoparticle toxicity. Several studies have highlighted the role of internalization routes in determining nanotoxicity. Here, we investigate how two endocytotic mechanisms (clathrin- and caveolae-mediated) impact on redox balance in gill and digestive gland of the mussel, Mytilus galloprovincialis. Animals were exposed (for 3, 6 and 12 h) to two sizes of silver nanoparticles (AgNP: <50 nm and <100 nm) prior to and after blockade of two endocytic pathways (amantadine blocks clathrin-mediated endocytosis while nystatin blocks caveolae-mediated endocytosis). Redox-proteomic tools were used to determine effects. Our results demonstrate the ability of both sizes of AgNP (<50 and <100 nm) to cause protein thiol oxidation and/or protein carbonylation. However, blockade of endocytotic routes mitigated AgNP toxicity. Differential ROS-related toxicity of AgNP to mussel tissues seemed to be linked to tissue-specific mode of action requirements. Cell uptake mechanism strongly influences toxicity of AgNPs in this filter-feeder
Changes in protein expression in mussels Mytilus galloprovincialis dietarily exposed to PVP/PEI coated silver nanoparticles at different seasons
Potential toxic effects of Ag NPs ingested through the food web and depending on the season have not been addressed in marine bivalves. This work aimed to assess differences in protein expression in the digestive gland of female mussels after dietary exposure to Ag NPs in autumn and spring. Mussels were fed daily with microalgae previously exposed for 24 hours to 10 µg/L of PVP/PEI coated 5 nm Ag NPs. After 21 days, mussels significantly accumulated Ag in both seasons and Ag NPs were found within digestive gland cells and gills. Two-dimensional electrophoresis distinguished 104 differentially expressed protein spots in autumn and 142 in spring. Among them, chitinase like protein-3, partial and glyceraldehyde-3-phosphate dehydrogenase, that are involved in amino sugar and nucleotide sugar metabolism, carbon metabolism, glycolysis/gluconeogenesis and the biosynthesis of amino acids KEGG pathways, were overexpressed in autumn but underexpressed in spring. In autumn, pyruvate metabolism, citrate cycle, cysteine and methionine metabolism and glyoxylate and dicarboxylate metabolism were altered, while in spring, proteins related to the formation of phagosomes and hydrogen peroxide metabolism were differentially expressed. Overall, protein expression signatures depended on season and Ag NPs exposure, suggesting that season significantly influences responses of mussels to NP exposure.This work has been funded by the Spanish Ministry of Economy and
Competitiveness (NanoSilverOmics project MAT2012-39372), Basque Government
(SAIOTEK project S-PE13UN142 and Consolidated Research Group GIC IT810-13) and the
University of the Basque Country UPV/EHU (UFI 11/37 and PhD fellowship to N.D.). This
study had also the support of Fundação para a Ciência e Tecnologia (FCT) from Portugal
through the Strategic Project UID/MAH00350/2013 granted to CIMA. The contribution
of K. Mehennaoui was possible within the project NanoGAM (AFR-PhD-9229040) and M.
Mikolaczyk was supported by a PhD fellowship from the French Ministry of Higher
Education and Research.info:eu-repo/semantics/acceptedVersio
The History of the Remains of the Roman Emperor, Julian the Apostate
Julian (Flavius Claudius Iulianus), called the Apostate, Roman emperor in the years 361–363, was one of the most intriguing rulers. From antiquity to the present day he invariably aroused great interest, both during his life and after his death. He was a just emperor, a wise commander, and a very talented writer. On 26 June 363 Julian the Apostate was mortally wounded during a battle with the Persians. He spent the last moments of his life discussing with philosophers Priskus and Maksimus the nobility of the soul, as we learn from the historian Ammianus Marcellinus. The ruler then showed, perhaps too ostentatiously, his greatest passion: love of virtue and fame. Julian the Apostate died at the age of thirty-two after only twenty months of his rule. Julian’s body, as Gregory of Nazianzus recalls, was transported from Nisibis to Tarsus in Cilicia, which took fifteen days. The subjects greeted the arrival of the body with a mournful lament or contemptuous insults, as the Father of the Church adds. Julian wanted to rest after death in Tarsus, in a mausoleum next to a small temple on the banks of the Cydnus River. Then, at an unspecified time, as the chronicler Zonaras recalls, the body of Emperor Julian the Apostate was transferred to Constantinople and buried in the Church of the Holy Apostles. Constantine Porphyrogenitus in his collection On the ceremonies of the imperial court (book II, chapter 42) mentions the grave of Julian. Today one of the porphyry sarcophagi, kept in the Archaeological Museum in Istanbul, is sometimes considered the Julian sarcophagus. The theme of this article is an attempt to determine the posthumous fate of Emperor Julian the Apostate’s body, i.e. when and in what circumstances it was transferred to Constantinople
Redox proteomic insights into involvement of clathrin-mediated endocytosis in silver nanoparticles toxicity to Mytilus galloprovincialis.
Clathrin-mediated endocytosis is a major mode of nanoparticle (NP) internalization into cells. However, influence of internalization routes on nanoparticle toxicity is poorly understood. Here, we assess the impact of blocking clathrin-mediated endocytosis upon silver NP (AgNP) toxicity to gills and digestive glands of the mussel Mytilusgalloprovincialisusing the uptake inhibitor, amantadine. Animals were exposed for 12h to AgNP (< 50 nm) in the presence and absence of amantadine. Labeling of oxidative protein modifications, either thiol oxidation, carbonyl formation or both in two-dimensional electrophoresis separations revealed 16 differentially affected abundance spots. Amongst these, twelve hypothetical proteins were successfully identified by peptide mass fingerprinting (MALDI TOF-MS/MS). The proteins identified are involved in buffering redox status or in cytoprotection. We conclude that blockade of clathrin-mediated endocytosis protected against NP toxicity, suggesting this uptake pathway facilitates toxicity. Lysosomal degradation and autophagy are major mechanisms that might be induced to mitigate NP toxicity
Coupling air stripping process and anaerobic digestion for the treatment of landfill leachate: organics degradation and cytotoxicity evaluation
Landfill leachate (LFL) from a controlled discharge in Tunisia was found to be highly loaded with ammonia. This study investigated the feasibility of an air stripping process aiming to mitigate the inhibitory effect of ammonia. Optimization of this process, using an orthogonal central composite design, intended to reduce the ammonia concentration and also to fix it in a safe range for the subsequent anaerobic process. Optimization showed that, to remove 60% of ammonia, pH, air flow rate, and reaction time should be fixed at 10.8, 6 L min−1, and 18 h, respectively. The air stripping process improved the anaerobic digestion (AD) of leachate in an upflow anaerobic fixed bed reactor. Chemical oxygen demand (COD) removal efficiency exceeded 80% at an organic loading rate (OLR) of 1.3 g COD L−1 day−1. Analysis of the organic compounds monitored by gas chromatography coupled to mass spectrometry (GC–MS) showed that contaminants were efficiently removed after the anaerobic process. Cytotoxicity was significantly reduced subsequent to the air stripping and anaerobic process
Histopathology and analyses of inflammation intensity in the gills of mussels exposed to silver nanoparticles: role of nanoparticle size, exposure time, and uptake pathways
<p>Environmentally induced perturbation of health parameters lead to morphological changes associated to the inflammatory response. Hematoxyline and eosin (H&E)-stained gill filaments sections were examined for such changes and inflammation intensity was scored according to a quantitative model in order to evaluate the health status of <i>in vivo</i> exposed (for 3, 6, and 12 h) mussels to silver nanoparticles (Ag-NPs <50 nm and Ag-NPs <100 nm) prior and after the inhibition of two potential uptake pathways (clathrin- and caveolae-mediated endocytosis) with the aid of pharmaceutical inhibitors (amantadine and nystatin). The impacts of the nanoparticles (NPs) size, as well as their uptake routes within different time of exposure on the inflammatory response were assessed. The results showed that Ag-NPs clearly induced morphological changes associated to the inflammatory response in gill tissues (Mann–Whitney <i>p</i> values were <.05). It is also clear that the length of the exposure as well as the NP size highly impacted inflammation intensity (highest histopathological indices recorded with Ag-NPs <100 nm). Also, the routes of NPs entry noticed to be major factor underlying inflammatory response (significant inflammation intensity reported with Ag-NPs <50 nm after blockade of uptake routes; <i>p</i> <.05). Throughout, it was concluded that inflammation intensity was related to NPs size and exposure time. Overall, uptake routes are shown to be the major factor underlying nanotoxicity.</p
Effect of exposure time, particle size and uptake pathways in immune cell lysosomal cytotoxicity of mussels exposed to silver nanoparticles
Differential Expression of Anti-Inflammatory RNA Binding Proteins in Lupus Nephritis
Lupus nephritis (LN) is a type of immunological complex glomerulonephritis characterized by chronic renal inflammation which is exacerbated by infiltrating leukocytes and fueled by a variety of pro-inflammatory cytokines. A profound understanding of the pathogenesis of LN is necessary to identify the optimal molecular targets. The role of RNA-binding proteins (RBPs) in post-transcriptional gene regulation in the immune system is being explored in greater depth to better understand how this regulation is implicated in inflammatory and autoimmune diseases. Tristetraprolin (TTP), Roquin-1/2, and Regnase-1 are 3 RBPs that play a critical role in the regulation of pro-inflammatory mediators by gating the degradation and/or translational silencing of target mRNAs. In this study, we proposed to focus on the differential expression of these RBPs in immune cells and renal biopsies from LN patients, as well as their regulatory impact on a specific target. Herein, we highlight a novel target of anti-inflammatory treatment by revealing the mechanisms underlying RBP expression and the interaction between RBPs and their target RNAs