280 research outputs found
Participation of the nucleobases in the regioselective backbone fragmentation of nucleic acids. A molecular dynamics and tandem mass spectrometric investigation on a model dinucleoside phosphotriester
The anions (I–III) obtained from O-methyl 5′-O-(5′-deoxythymidine) 3′-O-(2′,3′-dideoxyuridine) phosphate by the competitive removal of the 3-N-H protons of the nucleobases and of the methyl group from the phosphotriester bond, assume in the gas phase stable conformations as a function of their charge site. The mass-analyzed ion kinetic energy (MIKE) spectra of I and III show that the regioselective backbone cleavage of the internucleotidic linkage is controlled by the 2′-H proton transfer to the nucleobase within the 5′-end nucleoside. Similar pathways are taken by species II when the nucleobase is eliminated as neutral from the 5′-end nucleoside
Sulfonated Cellulose-Based Magnetic Composite as Useful Media for Water Remediation from Amine Pollutants
Commercially available microcrystalline cellulose (MCC) was functionalized using chlorosulfonic acid, while iron oxide nanoparticles (IONPs) were adsorbed on the surface of the cellulose derivative by the Massart's co-precipitation method. The obtained magnetite-decorated sulfate cellulose nanoparticles (MDSCNs) were characterized via Fourier transform infrared (FTIR) spectroscopy, scanning-electron microscopy (SEM), and elemental analysis, while the acidity of the functionalized cellulose was determined using an acid–base titration with phenolphthalein as an indicator. Furthermore, in order to determine the adsorptive power of the obtained composite, a series of analyses were performed on aqueous amine pollutants using flame ionization detection gas chromatography (GC-FID). The results of this study clearly show how a bio-compatible green polymer as cellulose can be easy functionalized in order to improve its chemical and physical properties, obtaining a magnetic composite useful in water purification. Adsorption percentages up to 90% and a very small amount of composite used (100 mg) proved how our material can be a powerful tool in environmental remediation
Biochar-Supported TiO2-Based Nanocomposites for the Photocatalytic Degradation of Sulfamethoxazole in Water—A Review
Sulfamethoxazole (SMX) is a frequently used antibiotic for the treatment of urinary tract,
respiratory, and intestinal infections and as a supplement in livestock or fishery farming to boost
production. The release of SMX into the environment can lead to the development of antibiotic
resistance among the microbial community, which can lead to frequent clinical infections. SMX
removal from water is usually done through advanced treatment processes, such as adsorption,
photocatalytic oxidation, and biodegradation. Among them, the advanced oxidation process using
TiO2 and its composites is being widely used. TiO2 is a widely used photocatalyst; however,
it has certain limitations, such as low visible light response and quick recombination of e/h+
pairs. Integrating the biochar with TiO2 nanoparticles can overcome such limitations. The biocharsupported
TiO2 composites showed a significant increase in the photocatalytic activities in the UVvisible
range, which resulted in a substantial increase in the degradation of SMX in water. The present
review has critically reviewed the methods of biochar TiO2 composite synthesis, the effect of biochar
integration with the TiO2 on its physicochemical properties, and the chemical pathways through
which the biochar/TiO2 composite degrades the SMX in water or aqueous solution. The degradation
of SMX using photocatalysis can be considered a useful model, and the research studies presented in
this review will allow extending this area of research on other types of similar pharmaceuticals or
pollutants in general in the future
Highly Diastereoselective Multicomponent Synthesis of Spirocyclopropyl Oxindoles Enabled by Rare-Earth Metal Salts
The synthesis of polysubstituted spirocyclopropyl oxindoles using a series of rare-earth metal (REM) salts is reported. REMs, in particular Sc(OTf)3, allowed access to the target compounds by a multicomponent reaction with high diastereoselectivity (≤94:6:0:0). Density functional theory calculations on the model reaction are consistent with the observed selectivity and revealed that the special coordinating capabilities and the oxophilicity of the metal are key factors in inducing the formation of one main diastereoisomer.The authors thank Diana Cabrera, Sebastiaan van Liempd, and Juan M. Falcon-Perez from the CIC bioGUNE Metabolomics Platform for performing the UPLC-MS/MS analyses. The authors also acknowledge the Italian Ministry of University and Research (MUR) for Project SI.F.I.PA.CRO.DE. - Sviluppo e industrializzazione farmaci innovativi per terapia molecolare personalizzata PA.CRO.DE. (PON ARS01_00568, CUP: B29C20000360005) and for two doctoral grants. Moreover, the authors thank the University of Calabria and Calabria Region (PAC CALABRIA 2014–2020-Asse Prioritario 12, Azione B 10.5.12 CUP: H28D19000040006) for financial support. This research was also funded by MCIN/AEI/10.13039/501100011033 (Grant PID2021-125946OB-I00 to G.J.-O. and Severo Ochoa Excellence Accreditation CEX2021-001136-S to CIC bioGUNE)
Racionalidad y deliberación en la acción colectiva
La teorÃa de la acción colectiva, tal y como fue formulada por Mancur Olson en 1965, se basaba en un concepto instrumental-estratégico de la racionalidad que ha sido el habitualmente utilizado en la teorÃa de la elección racional estándar. Diversos teóricos sociales (como Habermas o Elster) han tratado de desafiar esta concepción postulando un concepto alternativo de racionalidad que se base en la deliberación o la argumentación racional. En este artÃculo se discute hasta qué punto tales intentos han tenido éxito a la hora de ofrecer una alternativa teórica real a la racionalidad estratégica como mecanismo de generación y coordinación de las acciones colectivas. Para ello se plantearán tres cuestiones: 1) ¿Es la racionalidad comunicativa o deliberativa conceptualmente diferente de la racionalidad estratégica? 2) ¿Es empÃricamente plausible como principio explicativo de las acciones colectivas, y especialmente de las de los movimientos sociales? 3) ¿Es normativamente más defendible?The theory of collective action formulated by Mancur Olson in 1965 was based on an instrumental-strategic concept of rationality that has been generally used by standard rational choice theory. Different social theorists (such as Habermas or Elster) have tried to challenge this view by defending an alternative concept of rationality based on deliberation or rational argumentation. In this article I discuss to what extent these challenges have been successful in offering a real theoretical alternative to strategic rationality as a mechanism for the production and coordination of collective actions. For that purpose, three questions will be addressed: 1) Is communicative or deliberative rationality conceptually different from strategic rationality? 2) Is it empirically plausible as an explanatory principle for collective actions (and specially for those of social movements)? 3) Is it more defensible from a normative point of view
Highly Diastereoselective Multicomponent Synthesis of Spirocyclopropyl Oxindoles Enabled by Rare-Earth Metal Salts
Residential air pollution does not modify the positive association between physical activity and lung function in current smokers in the ECRHS study
Background: Very few studies have examined whether a long-term beneficial effect of physical activity on lung function can be influenced by living in polluted urban areas. Objective: We assessed whether annual average residential concentrations of nitrogen dioxide (NO2) and particulate matter with aerodynamic diameters = 2 times and >= 1 h per week) and forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were evaluated using adjusted mixed linear regression models. Models were conducted separately for never-and current smokers and stratified by residential long-term NO2, PM2.5 mass and PM10 mass concentrations ( 75th percentile (high)). Results: Among current smokers, physical activity and lung function were positively associated regardless of air pollution levels. Among never-smokers, physical activity was associated with lung function in areas with low/medium NO2, PM2.5 mass and PM10 mass concentrations (e.g. mean difference in FVC between active and non-active subjects was 43.0 mL (13.6, 72.5), 49.5 mL (20.1, 78.8) and 49.7 mL (18.6, 80.7), respectively), but these associations were attenuated in high air pollution areas. Only the interaction term of physical activity and PM10 mass for FEV1 among never-smokers was significant (p-value = 0.03). Conclusions: Physical activity has beneficial effects on adult lung function in current smokers, irrespective of residential air pollution levels in Western Europe. Trends among never-smokers living in high air pollution areas are less clear
Induction of a transmissible tau pathology by traumatic brain injury.
Traumatic brain injury is a risk factor for subsequent neurodegenerative disease, including chronic traumatic encephalopathy, a tauopathy mostly associated with repetitive concussion and blast, but not well recognized as a consequence of severe traumatic brain injury. Here we show that a single severe brain trauma is associated with the emergence of widespread hyperphosphorylated tau pathology in a proportion of humans surviving late after injury. In parallel experimental studies, in a model of severe traumatic brain injury in wild-type mice, we found progressive and widespread tau pathology, replicating the findings in humans. Brain homogenates from these mice, when inoculated into the hippocampus and overlying cerebral cortex of naïve mice, induced widespread tau pathology, synaptic loss, and persistent memory deficits. These data provide evidence that experimental brain trauma induces a self-propagating tau pathology, which can be transmitted between mice, and call for future studies aimed at investigating the potential transmissibility of trauma associated tau pathology in humans
Time course of risk factors associated with mortality of 1260 critically ill patients with COVID-19 admitted to 24 Italian intensive care units
Purpose: To evaluate the daily values and trends over time of relevant clinical, ventilatory and laboratory parameters during the intensive care unit (ICU) stay and their association with outcome in critically ill patients with coronavirus disease 19 (COVID-19). Methods: In this retrospective–prospective multicentric study, we enrolled COVID-19 patients admitted to Italian ICUs from February 22 to May 31, 2020. Clinical data were daily recorded. The time course of 18 clinical parameters was evaluated by a polynomial maximum likelihood multilevel linear regression model, while a full joint modeling was fit to study the association with ICU outcome. Results: 1260 consecutive critically ill patients with COVID-19 admitted in 24 ICUs were enrolled. 78% were male with a median age of 63 [55–69] years. At ICU admission, the median ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2) was 122 [89–175] mmHg. 79% of patients underwent invasive mechanical ventilation. The overall mortality was 34%. Both the daily values and trends of respiratory system compliance, PaO2/FiO2, driving pressure, arterial carbon dioxide partial pressure, creatinine, C-reactive protein, ferritin, neutrophil, neutrophil–lymphocyte ratio, and platelets were associated with survival, while for lactate, pH, bilirubin, lymphocyte, and urea only the daily values were associated with survival. The trends of PaO2/FiO2, respiratory system compliance, driving pressure, creatinine, ferritin, and C-reactive protein showed a higher association with survival compared to the daily values. Conclusion: Daily values or trends over time of parameters associated with acute organ dysfunction, acid–base derangement, coagulation impairment, or systemic inflammation were associated with patient survival
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