Ionotropic and metabotropic glutamate receptor mediation of glucocorticoid-induced apoptosis in hippocampal cells and the neuroprotective role of synaptic N-methyl-D-aspartate receptors

Glutamate receptors have been proposed to mediate the apoptotic actions of glucocorticoids in hippocampal cells. To further analyze the role of glutamate receptors in this process, we pretreated primary hippocampal cells from neonatal (postnatal day 4) rats with antagonists of ionotropic glutamate receptor (iGluR) and metabotropic glutamate receptor (mGluR) antagonists before exposure to the specific glucocorticoid receptor agonist dexamethasone (DEX) at a dose of 1 μM. Dizocilpine (MK801; a general N-methyl-Daspartic acid [NMDA] receptor antagonist, NMDAR antagonist) and ifenprodil (a specific ligand of the NMDAR 2B subunit, NR2B), were used to block iGluR; (RS)-α-ethyl-4-carboxyphenylglycine (E4CPG) and (RS)-α-cyclopropyl-4- phosphonophenyl-glycine (CPPG) were employed as I/II (E4CPG) and II/III (CPPG) mGluR antagonists. Blockade of iGluR resulted in a significant attenuation of DEX-induced cell death; the finding that ifenprodil exerted a similar potency to MK801 demonstrates the involvement of NR2B receptors in glucocorticoid-induced cell death. Apoptosis accounted for a significant amount of the cell loss observed, as detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling histochemistry for the in situ labeling of DNA breaks; apoptotic cells were distinguished from necrosis on the basis of morphological criteria, including chromatin condensation, membrane blebbing and presence of apoptotic bodies. Treatment with E4CPG and CPPG completely abolished the apoptotic response to DEX, thus showing the additional contribution of mGluR to the phenomenon. Further, dose-response studies with NMDA revealed that whereas high (10 μM) doses of NMDA themselves elicit cytotoxic responses, low (1–5 μM) concentrations of NMDA can effectively oppose DEX-induced cell death. Interestingly, the neuroprotective actions of low dose NMDA stimulation were abolished when either synaptic or extrasynaptic NMDA receptors were blocked with MK801 in combination with the GABA receptor antagonist bicuculline (synaptic) or ifenprodil (extrasynaptic). In summary, the present data show that both iGluR and mGluR mediate the neurotoxic effects of glucocorticoids on hippocampal cells and that pre-treatment with low doses of NMDA, by acting on synaptic and extrasynaptic receptors, render hippocampal cells less vulnerable to glucocorticoid insults.German Academic Exchange Service - Personnel Exchange Acções Integradas Luso-Alemãs The Portuguese Rectors’ Conference Portuguese Institute for International Co-operation in Science and Technolog

Impact de la variabilité climatique sur la production du maïs et de l’igname en Zones Centre et Nord de la Côte d’Ivoire

En Côte d’Ivoire, les perturbations pluviométriques impactent la production agricole en agriculture pluviale conventionnelle. C’est donc dans ce contexte que cette étude est menée, afin d’analyser les variations climatiques et leurs incidences sur les tendances de productions du maïs et de l’igname en zones Centre et Nord du pays. L’application des tests de stationnarité aux données pluviométriques stationnelles a permis de déterminer des années de ruptures : 1982 pour Odienné, 1980 pour Katiola, 1966 pour Séguéla et 1970 pour Korhogo ; toutefois, on note une absence de rupture au niveau de Bondoukou. Les déficits pluviométriques calculés dans ces stations oscillent entre 13 % et 22 %. Pourtant, les corrélations linéaires établies entre les rendements du maïs et de l’igname d’une part, et la durée des saisons culturales d’autre part, ont montré qu’il n’existe pas de relation linéaires explicites entre ces deux variables. En effet, la seule connaissance du régime pluviométrique ne suffit pas à expliquer les rendements agricoles ; car un rendement faible peut aussi bien résulter de conditions hydriques déficitaires qu’excédentaires.Mots-clés: Variabilité climatique, production agricole, zones centre et nord, Côte d’IvoireEnglish Title:  Climate variability impact on corn and yam production in the central and northern Areas of Côte d’IvoireEnglish AbstractIn Ivory Coast, rainfall disturbances hinder real-time development of these rainfed especially in central and northern areas. This study was conducted to analyze climate changes and their impact on trends in maize and yam production in the below mentioned areas. The application of the statistical tests in the pluviometric data of the study area allowed clearing the years of breaks. It is about 1982 for Odienné, 1980 for Katiola, 1966 for Séguéla and 1970 for Korhogo. No break was detected in the station of Bondoukou. The pluviometric deficits calculated for that purpose oscillate between 13 % and 22 %. The linear correlations established between the agricultural yields and the duration of the cultural seasons over the period 1984 in 2000 show that there is no significant relation. Indeed, the only knowledge of rainfall conditions is not enough to explain crop yields : a low yield can result as well from hydric conditions overdrawn as positive.Keywords: climatic variability, agricultural production, central and northern areas, Côte d’Ivoir

Halloysite Nanotubes Noncovalently Functionalised with SDS Anionic Surfactant and PS-b-P4VP Block Copolymer for Their Effective Dispersion in Polystyrene as UV-Blocking Nanocomposite Films

Asimple and versatilemethod is reported for the noncovalent functionalisation of natural and "green" halloysite nanotubes (HNTs) allowing their effective dispersion in a polystyrene (PS) thermoplastic matrix via solvent mixing. Initially, HNTs (pristine HNTs) were modified with physically adsorbed surfactant molecules of sodium dodecyl sulphate (SDS) and PS-b-P4VP [P4VP: poly(4-vinylpyridine)] block copolymer (BCP). Hereafter, SDS and BCP modified HNTs will be indicated as SDS-m-HNT and BCP-m-HNT.Nanocomposite films with 1, 2, and 5 wt.%HNTloadingswere prepared, abbreviated as PS-SDS-m-HNT1, PS-SDS-m-HNT2, and PS-SDS-m-HNT5 and PS-BCP-m-HNT1, PS-BCP-m-HNT2, and PS-BCP-m-HNT5 (where 1, 2, and 5 correspond to the wt.% of HNTs). All nanocomposites depicted improved thermal degradation compared to the neat PS as revealed by thermogravimetric analysis (TGA). Transmission electron microscopy (TEM) confirmed the good dispersion state of HNTs and the importance of modification by SDS and BCP. X-ray diffraction (XRD) studies showed the characteristic interlayer spacing between the two silicate layers of pristine and modified HNTs. The PS/HNT nanocomposite films exhibited excellent ultraviolent-visible (UV-vis) absorbance properties and their potential application as UV-filters could be envisaged

Halloysite Nanotubes Noncovalently Functionalised with SDS Anionic Surfactant and PS-b-P4VP Block Copolymer for Their Effective Dispersion in Polystyrene as UV-Blocking Nanocomposite Films

A simple and versatile method is reported for the noncovalent functionalisation of natural and “green” halloysite nanotubes (HNTs) allowing their effective dispersion in a polystyrene (PS) thermoplastic matrix via solvent mixing. Initially, HNTs (pristine HNTs) were modified with physically adsorbed surfactant molecules of sodium dodecyl sulphate (SDS) and PS-b-P4VP [P4VP: poly(4-vinylpyridine)] block copolymer (BCP). Hereafter, SDS and BCP modified HNTs will be indicated as SDS-m-HNT and BCP-m-HNT. Nanocomposite films with 1, 2, and 5 wt.% HNT loadings were prepared, abbreviated as PS-SDS-m-HNT1, PS-SDS-m-HNT2, and PS-SDS-m-HNT5 and PS-BCP-m-HNT1, PS-BCP-m-HNT2, and PS-BCP-m-HNT5 (where 1, 2, and 5 correspond to the wt.% of HNTs). All nanocomposites depicted improved thermal degradation compared to the neat PS as revealed by thermogravimetric analysis (TGA). Transmission electron microscopy (TEM) confirmed the good dispersion state of HNTs and the importance of modification by SDS and BCP. X-ray diffraction (XRD) studies showed the characteristic interlayer spacing between the two silicate layers of pristine and modified HNTs. The PS/HNT nanocomposite films exhibited excellent ultraviolent-visible (UV-vis) absorbance properties and their potential application as UV-filters could be envisaged

Ni Catalysts Based on Attapulgite for Hydrogen Production through the Glycerol Steam Reforming Reaction

Attapulgite (ATP, a natural clay) was used as carrier to produce a nickel-based catalyst (Ni/ATP) for the work that is presented herein. Its catalytic performance was comparatively assessed with a standard Ni/Al2O3 sample for the glycerol steam reforming (GSR) reaction. It was shown that the ATP support led to lower mean Ni crystallite size, i.e., it increased the dispersion of the active phase, to the easier reduction of NiO and also increased the basicity of the catalytic material. It was also shown that it had a significant effect on the distribution of the gaseous products. Specifically, for the Ni/ATP catalyst, the production of liquid effluents was minimal and subsequently, conversion of glycerol into gaseous products was higher. Importantly, the Ni/ATP favored the conversion into H2 and CO2 to the detriment of CO and CH4. The stability experiments, which were undertaken at a low WGFR, showed that the activity of both catalysts was affected with time as a result of carbon deposition and/or metal particle sintering. An examination of the spent catalysts revealed that the coke deposits consisted of filamentous carbon, a type that is known to encapsulate the active phase with fatal consequences

Theoretical Investigation of the Deactivation of Ni Supported Catalysts for the Catalytic Deoxygenation of Palm Oil for Green Diesel Production

For the first time, a fully comprehensive heterogeneous computational fluid dynamic (CFD) model has been developed to predict the selective catalytic deoxygenation of palm oil to produce green diesel over an Ni/ZrO2 catalyst. The modelling results were compared to experimental data, and a very good validation was obtained. It was found that for the Ni/ZrO2 catalyst, the paraffin conversion increased with temperature, reaching a maximum value (>95%) at 300 °C. However, temperatures greater than 300 °C resulted in a loss of conversion due to the fact of catalyst deactivation. In addition, at longer times, the model predicted that the catalyst activity would decline faster at temperatures higher than 250 °C. The CFD model was able to predict this deactivation by relating the catalytic activity with the reaction temperature

The effect of noble metal (M: Ir, Pt, Pd) on M/Ce2 O3-¿-Al2 O3 catalysts for hydrogen production via the steam reforming of glycerol

A promising route for the energetic valorisation of the main by-product of the biodiesel industry is the steam reforming of glycerol, as it can theoretically produce seven moles of H2 for every mole of C3 H8 O3. In the work presented herein, CeO2 –Al2 O3 was used as supporting material for Ir, Pd and Pt catalysts, which were prepared using the incipient wetness impregnation technique and characterized by employing N2 adsorption–desorption, X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The catalytic experiments aimed at identifying the effect of temperature on the total conversion of glycerol, on the conversion of glycerol to gaseous products, the selectivity towards the gaseous products (H2, CO2, CO, CH4) and the determination of the H2 /CO and CO/CO2 molar ratios. The main liquid effluents produced during the reaction were quantified. The results revealed that the Pt/CeAl catalyst was more selective towards H2, which can be related to its increased number of Brønsted acid sites, which improved the hydrogenolysis and dehydrogenation–dehydration of condensable intermediates. The time-on-stream experiments, undertaken at low Water Glycerol Feed Ratios (WGFR), showed gradual deactivation for all catalysts. This is likely due to the dehydration reaction, which leads to the formation of unsaturated hydrocarbon species and eventually to carbon deposition. The weak metal–support interaction shown for the Ir/CeAl catalyst also led to pronounced sintering of the metallic particles

Learning Organizational Culture in Greek Public Hospitals

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. (1) Background: A learning organizational culture is crucial to the safety of patients and the quality of public health care. The aim of this study was to assess the learning organizational culture and capacity of Greek public hospitals. (2) Materials and Methods: A cross-sectional analysis was carried out in six public general hospitals and stratified sampling was used as the sampling technique. A total of 480 questionnaires were distributed to health care professionals and 380 valid questionnaires were returned (78% response rate). The comprehensive form of the Dimensions of Learning Organization Questionnaire (DLOQ), which was adapted and translated into Greek, was used for data collection in this survey. (3) Results: The level of learning organizational culture and capacity in the health units are very low. All seven dimensions of the learning organizational instrument are lower than the theoretically neutral median (3.0). Health care employees believe that the hospital’s existing culture and management practices do not foster and contribute to continuing learning, which is the fundamental aspect of self-development, department development and performance improvement. (4) Conclusions: Greek public hospitals need to adopt different types of leadership practices and culture in order to be able to facilitate organizational learning. Organizational learning (OL) is based on collaborative working, a culture that encompasses learning as participation in the organizational work practice. This transformation of culture should take place at all levels of learning to enhance results

Nanoparticle Exsolution from Nanoporous Perovskites for Highly Active and Stable Catalysts

Nanoporosity is clearly beneficial for the performance of heterogeneous catalysts. Although exsolution is a modern method to design innovative catalysts, thus far it is predominantly studied for sintered matrices. A quantitative description of the exsolution of Ni nanoparticles from nanoporous perovskite oxides and their effective application in the biogas dry reforming is here presented. The exsolution process is studied between 500 and 900 °C in nanoporous and sintered La$_{0.52}$Sr$_{0.28}$Ti$_{0.94}$Ni$_{0.06}$O$_{3±δ}$. Using temperature-programmed reduction (TPR) and X-ray absorption spectroscopy (XAS), it is shown that the faster and larger oxygen release in the nanoporous material is responsible for twice as high Ni reduction than in the sintered system. For the nanoporous material, the nanoparticle formation mechanism, studied by in situ TEM and small-angle X-ray scattering (SAXS), follows the classical nucleation theory, while on sintered systems also small endogenous nanoparticles form despite the low Ni concentration. Biogas dry reforming tests demonstrate that nanoporous exsolved catalysts are up to 18 times more active than sintered ones with 90% of CO$_2$ conversion at 800 °C. Time-on-stream tests exhibit superior long-term stability (only 3% activity loss in 8 h) and full regenerability (over three cycles) of the nanoporous exsolved materials in comparison to a commercial Ni/Al$_2$O$_3$ catalyst

Importance of feeding behaviour on life cycle in the zoophytophagous bug Dicyphus geniculatus

Dicyphus geniculatus (Fieber) (Heteroptera Miridae) is a Mediterranean mirid that has been observed in public green areas in towns of eastern and western provinces of Spain feeding on whiteflies and thrips on Dianthus caryophyllus L. carnations. In this article, the relative importance of feeding behaviour with respect to the duration of nymphal development and nymphal survival, as well as reproduction, was investigated. Nymphs of Bemisia tabaci (Gennadius), larvae of Frankliniella occidentalis (Pergande) and carnation plants introduced into a 50 × 50 × 50 cm methacrylate box, together with adults mirids, in a climate-controlled chamber (25 ± 1 °C, 60 ± 5% HR, 16:8 h L:D photoperiod) were used to analyse feeding behaviour. In particular, data on realised fecundity, sex ratio and adult longevity were analysed. Realised fecundity differed significantly with respect to prey availability (F1, 267 = 44504.92; p ≤ 0.001). The sex ratio did not differ from 1(♂♂):2(♀♀+♂♂) with respect to feeding regimes [“with B. tabaci prey” (37/53+37 = 0.41), χ2 = 1.434, df 1, p = 0.231, “with F. occidentalis prey” (42/50+42 = 0.46), χ2 = 0.200, df 1, p = 0.655] or prey type (B. tabaci or F. occidentalis, χ2 = 0.564, df 1, p = 0.453). Adult longevity differed significantly in terms of prey availability (F2, 534 = 58.89, p ≤ 0.001) and longevity differed for each sex within each feeding regime (F1, 534 = 14.13; p ≤ 0.001). D. geniculatus can survive on a host plant diet exclusively but could not complete its development in the absence of supplemental prey food, indicating that D. geniculatus requires an animal component in its diet. Other zoophytophagous dicyphines are successfully used as beneficials in integrated pest management in horticultural crops. Thus, D. geniculatus has a potential role in the biological control of carnation pests, and therefore may be a promising pest biological control agent, thus contributing to urban area sustainability