Kinetics of the curing reaction of a diglycidyl ether of bisphenol A with a modified polyamine

Differential scanning calorimetry (DSC) was used at different heating rates to study the cure kinetics of the diglycidyl ether of bisphenol A (DGEBA) with a polyaminophenolic product (PAP) derived from the modification of tetraethylenepentamine (TEPA). The activation energy (E-a) based on a single heating rate was compared with E-a based on multiple heating rates (Kissinger, isoconversional method). (C) 2005 Elsevier B.V. All rights reserved

Online information on face masks: analysis of websites in Italian and English returned by different search engines.

OBJECTIVE: Countries have major differences in the acceptance of face mask use for the prevention of COVID-19. This work aims at studying the information online in different countries in terms of information quality and content. DESIGN: Content analysis. METHOD: We analysed 450 webpages returned by searching the string 'are face masks dangerous' in Italy, the UK and the USA using three search engines (Bing, Duckduckgo and Google) in August 2020. The type of website and the stance about masks were assessed by two raters for each language and inter-rater agreement reported as Cohen's kappa. The text of the webpages was collected from the web using WebBootCaT and analysed using a corpus analysis software to identify issues mentioned. RESULTS: Most pages were news outlets, and few (2%-6%) from public health agencies. Webpages with a negative stance on masks were more frequent in Italian (28%) than English (19%). Google returned the highest number of mask-positive pages and Duckduckgo the lowest. Google also returned the lowest number of pages mentioning conspiracy theories and Duckduckgo the highest. Webpages in Italian scored lower than those in English in transparency (reporting authors, their credentials and backing the information with references). When issues about the use of face masks were analysed, mask effectiveness was the most discussed followed by hypercapnia (accumulation of carbon dioxide), contraindication in respiratory disease and hypoxia, with issues related to their contraindications in mental health conditions and disability mentioned by very few pages. CONCLUSIONS: This study suggests that: (1) public health agencies should increase their web presence in providing correct information on face masks; (2) search engines should improve the information quality criteria in their ranking; (3) the public should be more informed on issues related to the use of masks and disabilities, mental health and stigma arising for those people who cannot wear masks

Thermal analysis study of the interactions between acetaminophen and excipients in solid dosage forms and in some binary mixtures

Thermogravimetry (TG) and differential scanning calorimetry (DSC) were used to assess the compatibility between acetaminophen (Ac) and some excipients (polyvinylpyrrolidone (P), magnesium stearate (M), citric acid (C), aspartame (As), mannitol (Mn), cellulose (Cll) and starch (S)) in several of the more commercially available pharmaceutical formulations and in solid binary mixtures. The present study compared thermodynamic data on acetaminophen melting and vaporization processes of pure acetaminophen with those found for several solid mixtures and in some commercially available acetaminophen-based dosage forms. Appreciable modifications occur only for solid mixtures with high content of excipient. Acetaminophen-based dosage forms and its solid binary mixtures usually show "additivity" of calorimetric peaks number of pure components in their calorimetric curve profiles, thus revealing a good thermoanalytical compatibility between acetaminophen and the excipients examined, except for samples containing appreciable content of mannitol. © 2004 Elsevier B.V. All rights reserved

Arsenite-induced mitochondrial superoxide formation: time and concentration requirements for the effects of the metalloid on the endoplasmic reticulum and mitochondria

The present study used human myeloid leukemia cells, a versatile promonocytic cellular system which, based on its endoplasmic reticulum (ER)/mitochondria functional relationships, respond to low micromolar concentrations of arsenite with a single, defined mechanism of superoxide (O2-.) formation. Under these conditions, we observe an initial Ca2+ mobilization from the ER associated with the mitochondrial accumulation of the cation, followed by Ca2+-dependent mitochondrial O2-. (mitoO2-.) formation. These events, barely detectable after 3 h were better appreciated at 6 h. We found that remarkably shorter exposure to, and lower concentrations of, arsenite are required to induce extensive O2-. formation in cells supplemented with inositol-1,4,5-trisphosphate receptor (IP3R) or ryanodine receptor (RyR) agonists. Indeed, nanomolar arsenite induced maximal O2-. formation after only 10 min of exposure, and this response was uniquely dependent on the enforced mitochondrial Ca2+ accumulation. The dramatic anticipation of, sensitization to, the effects of arsenite caused by the IP3R or RyR agonists was accompanied by a parallel significant genotoxic response in the absence of detectable mitochondrial dysfunction and cytotoxicity. We conclude that the prolonged, low micromolar arsenite exposure paradigm resulting in mitoO2-. formation is necessary to affect Ca2+ homeostasis and accumulate the cation in mitochondria. The arsenite requirements to promote mitoO2-. formation in the presence of sufficient mitochondrial Ca2+ were instead remarkably lower in terms of both concentration and time of exposure. These conditions were associated with the induction of extensive DNA strand scission in the absence of detectable signs of toxicity. SIGNIFICANCE STATEMENT: In RP-cells, arsenite causes mitochondrial Ca2+ accumulation ([Ca2+]m) and Ca2+-dependent mitochondrial superoxide formation. We now report that the second event requires remarkably lower concentrations of /time of exposure to the metalloid than the former. Indeed, a brief exposure to nanomolar levels of arsenite produced maximal effects under conditions in which the [Ca2+]m was increased by IP3R or RyR agonists. Hence, specific substances or conditions enhancing the [Ca2+]m, may potentiate the deleterious effects of arsenite by selectively increasing mitochondrial superoxide formation

Functional organization of the endoplasmic reticulum dictates the susceptibility of target cells to arsenite-induced mitochondrial superoxide formation, mitochondrial dysfunction and apoptosis

Arsenite induces many critical effects associated with the formation of reactive oxygen species (ROS) through different mechanisms. We focused on Ca2+-dependent mitochondrial superoxide (mitoO2-.) formation and addressed questions on the effects of low concentrations of arsenite on the mobilization of the cation from the endoplasmic reticulum and the resulting mitochondrial accumulation. Using various differentiated and undifferentiated cell types uniquely expressing the inositol-1, 4, 5-triphosphate receptor (IP3R), or both the IP3R and the ryanodine receptor (RyR), we determined that expression of this second Ca2+ channel is an absolute requirement for mitoO2-. formation and for the ensuing mitochondrial dysfunction and downstream apoptosis. In arsenite-treated cells, RyR was recruited after IP3R stimulation and agonist studies provided an indirect indication for a close apposition between RyR and mitochondria. It was also interesting to observe that arsenite fails to promote mitochondrial Ca2+ accumulation, mitoO2-. formation and mitochondrial toxicity in RyR-devoid cells, in which the IP3R is in close contact with the mitochondria. We therefore conclude that low dose arsenite-induced mitoO2- formation, and the resulting mitochondrial dysfunction and toxicity, are prerequisite of cell types expressing the RyR in close apposition with mitochondria

Durum Wheat Production as Affected by Soil Tillage and Fertilization Management in a Mediterranean Environment

Several strategies have been proposed recently to reduce the accumulated harmful circumstances of intensive conventional farming practices. The adoption of conservation soil tillage and organic fertilization techniques could contribute to achieving this goal. The study was conducted over a three-year trial to assess the effects of soil tillage practices (plough; subsoil; spading) and fertilization management (inorganic vs. organic) on durum wheat growth dynamics and productivity in a Mediterranean environment. The chlorophyll concentration (CC) was evaluated using an MC-100 chlorophyll meter, and Green Area (GA) was extracted from red-green-blue (RGB) digital images acquired with a commercially available digital camera. These non-destructive low-cost methods were used to examine crop status and its reactions to climate conditions over three consecutive growing seasons in the field. A positive strong linear relationship between both CC and GA against grain yield in each growing season was identified. The study highlights that CC and GA methods are valuable tools to assess crop development under Mediterranean conditions. The results indicated that the applied conservation tillage systems, such as subsoil tillage and using the spading machine, along with organic fertilization with compost, are valuable choices in the Mediterranean basin for sustainable and higher crop production (13%) compared to the conventional traditional system

Durum Wheat–Potato Crop Rotation, Soil Tillage, and Fertilization Source Affect Soil CO₂ Emission and C Storage in the Mediterranean Environment

At present, the role of agricultural practices on the dynamic of GHGs is being investigated worldwide. In this study, the effects of soil tillage practices (conventional vs. conservation techniques) and fertilization sources (inorganic vs. organic) on soil CO2 emissions in durum wheat (Triticum durum Desf.)–potato (Solanum tuberosum L.) rotation in the Mediterranean area were evaluated. This study aimed to understand the changes in the soil carbon content and the soil CO2 emissions under different soil tillage practices (moldboard plow (P), subsoiler (R), and spading machine (S)) and fertilization sources (mineral (M) and organic (O) with municipal organic waste). Soil CO2 flux, soil water content, and soil temperature data were collected for both crops using a portable closed-chamber infrared gas dynamics system. Significant relationships were detected between soil CO2 emissions and soil temperate and soil water content. However, these relationships were found only for durum wheat crops. Our findings indicate that including sustainable agricultural practices in wheat–potato rotation system could act as an appropriate alternative option to increase soil organic carbon, mitigate CO2 emissions, and reduce the dependence on chemical inputs and energy