Search results for "25"
showing 10 items of 3263 documents
Profiles and Sources of PAHs in Sediments from an Open-Pit Mining Area in the Peruvian Andes
2015
The Peruvian Andes are one of the most productive areas for mining and therefore also one of the most exposed to these sources of pollution. This article reports the characterization of Polycyclic Aromatic Hydrocarbons (PAHs) in sediments of Cerro de Pasco area (Peru) located close to a large open-pit mine and, in recent years, several reports have provided evidence of environmental contamination and related health problems. Investigations were carried out into the fifteen PAHs identified by the US-Environment Protection Agency (US-EPA) as requiring priority monitoring, other non US-EPA listed PAHs and perylene were also investigated in order to obtain further information on their origins. …
18F-Radiolabeling, Preliminary Evaluation of Folate-pHPMA Conjugates via PET
2014
The synthesis of a 10.5 kDa and a 52.5 kDa polymer, based on pHPMA functionalized with tyramine for (18) F-labeling and a folate derivative as targeting moiety, is reported. FCS studies are conducted using Oregon Green-labeled conjugates. No aggregation is observed for the 10.5 kDa conjugate, but strong aggregation for the 52.5 kDa conjugate. In vivo studies are conducted using Walker-256 mammary carcinoma model to determine body distribution as function of size and especially targeting unit. These in vivo studies show a higher short time (2 h) accumulation for both conjugates in the tumor than for untargeted pHPMA, confirmed by blockade studies. The 10.5 kDa polymer accumulates with 0.46% …
L -lysine and EDTA polymer mimics as resins for the quantitative and reversible removal of heavy metal ion water pollutants
2012
Traditional precipitation methods for inorganic micropollutant removal from waters are increasingly being replaced by sorption methods based on both natural and synthetic materials. In this context, two novel effective heavy metal ions absorbers are presented. These resins, LYMA and LMT85, were crosslinked poly(amidoamine)s carrying amine and carboxyl groups in their repeating units. In particular, the LYMA-repeating unit contains one carboxyl and two amine groups and is a mimic of L-lysine, whereas LMT85 contains two amine and five carboxyl groups and is a mimic of EDTA. Both resins were prepared at moderate cost by simple eco-friendly procedures. The heavy metal ion set adopted as benchma…
Atom transfer radical polymerization with different halides (F, Cl, Br, and I): Is the process "living" in the presence of fluorinated initiators?
2016
Atom transfer radical polymerization (ATRP) is often used for grafting from fluorinated polymers. Nevertheless, the possibility to initiate an ATRP from a C-F functionality and the activity of the catalysts in the presence of fluoride anions are essentially unexplored. Therefore, we investigated the thermodynamics and kinetics of C-F bond activation by ATRP catalysts and compared it with other halide systems. The ATRP equilibrium constant was estimated to be small for the reaction between [CuITPMA]+ and benzyl fluoride (TPMA = tris(2-pyridylmethyl)- amine). However, [CuITPMA] + could react with the more active initiator diethyl fluoromalonate (DEFM). With DEFM as initiator and CuIBr/TPMA as…
Uniform estimates for the X-ray transform restricted to polynomial curves
2012
We establish near-optimal mixed-norm estimates for the X-ray transform restricted to polynomial curves with a weight that is a power of the affine arclength. The bounds that we establish depend only on the spatial dimension and the degree of the polynomial. Some of our results are new even in the well-curved case.
Olive mill wastewaters decontamination based on organo-nano-clay composites
2019
Abstract Green composites for environmental applications were successfully prepared by intercalation of the biosurfactant Quillaja saponin onto montmorillonite mineral clay on varying pH and surfactant/clay ratio. Equilibrium adsorption isotherms were constructed and the system was characterized by performing TGA and XRD analyses. The efficiency of the surfactant-modified clay in the removal of the organic content present in olive mill wastewaters (OMW) was evaluated by means of spectrophotometric measurements. The interest for this cogent issue comes from the consideration that, despite their high pollutant content, OMW can be considered as a potential resource of several organic compounds…
Antioxidant phenolic compounds recovery from Mangifera indica L. by-products by supercritical antisolvent extraction
2015
Abstract Supercritical Antisolvent Extraction (SAE) was used in the recovery of antioxidant compounds from mango by-products. The antioxidant extract was obtained by solid–liquid extraction using aqueous acetone (80% v/v) and subsequent adsorption/desorption in C18 cartridge. Recovery of antioxidants was performed by SAE using SC-CO 2 as antisolvent. The temperature and pressure parameters were varied in the range 35–45 °C and 8–15 MPa. The SAE process allowed the recovery of about 90% of the initial phenolic compounds, the best recovery was obtained at 40 °C and 10 MPa and the main compounds were mangiferin, isomangiferin, quercetin 3-O-galactoside, quercetin 3-O-glucoside, quercetin 3-O-x…
A Case of Cardiomyopathy Due to Premature Ductus Arteriosus Closure: The Flip Side of Paracetamol.
2017
Paracetamol (acetaminophen or N-acetyl-p-aminophenol) is considered a safe analgesic and antipyretic nonsteroidal antiinflammatory drug commonly used during pediatric ages and during pregnancy. We report on a term neonate with closed ductus arteriosus, severe cardiomyopathy, right ventricular dysfunction, and functional stenosis of pulmonary arteries at birth after maternal self-medication with paracetamol and consumption of polyphenol-rich foods in late pregnancy. This drug, especially when associated with other vasoconstrictors (such as polyphenols), interferes with prostaglandin metabolism, which seriously accentuates the intrauterine ductus arteriosus constriction and leads to pharmacol…
Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight
2021
From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia…
Use of a running coupling in the NLO calculation of forward hadron production
2018
We address and solve a puzzle raised by a recent calculation [1] of the cross-section for particle production in proton-nucleus collisions to next-to-leading order: the numerical results show an un- reasonably large dependence upon the choice of a prescription for the QCD running coupling, which spoils the predictive power of the calculation. Specifically, the results obtained with a prescription formulated in the transverse coordinate space differ by one to two orders of magnitude from those obtained with a prescription in momentum space. We show that this discrepancy is an artefact of the interplay between the asymptotic freedom of QCD and the Fourier transform from coordinate space to mo…