In this work, the adsorption features of clays with the magnetic properties of iron oxides have been combined in a composite to produce a magnetic adsorbent. These magnetic composites can be used as ...adsorbent for contaminants in water and can be subsequently removed from the medium by a simple magnetic process. The bentonite–iron oxide magnetic composites have been prepared with weight ratios of 2:1, 1.5:1, and 1:1 and characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TG), magnetization measurements, chemical analyses, temperature-programmed reduction (TPR), N
2 adsorption–desorption isotherms, Mössbauer spectroscopy, and scanning electron microscopy (SEM). The results suggest that the main magnetic phase present is maghemite (γ-Fe
2O
3). A magnetization enhancement can be produced by treatment with H
2 at 600 °C to reduce maghemite to magnetite. Nitrogen adsorption isotherms showed that the surface area and microporosity increased from 7 m
2 g
−1 (
V
micropores=0.003 cm
3 g
−1) for the pure bentonite to 55 m
2 g
−1 (
V
micropores=0.009 cm
3 g
−1) for the composite clay/iron oxide (2:1). The adsorption isotherms of metal ions Ni
2+, Cu
2+, Cd
2+, and Zn
2+ from aqueous solution onto the composites also showed that the presence of iron oxide produced an increase on the adsorption capacity of the bentonite.
In this work the adsorption features of activated carbon and the magnetic properties of iron oxides were combined in a composite to produce magnetic adsorbents. These magnetic particles can be used ...as adsorbent for a wide range of contaminants in water and can subsequently be removed from the medium by a simple magnetic procedure. Activated carbon/iron oxide magnetic composites were prepared with weight ratios of 2:1, 1.5:1 and 1:1 and characterized by powder XRD, TG, magnetization measurements, chemical analyses, TPR, N
2 adsorption–desorption isotherms, Mössbauer spectroscopy and SEM. The results suggest that the main magnetic phase present is maghemite (γ-Fe
2O
3) with small amounts of magnetite (Fe
3O
4). Magnetization enhancement can be produced by treatment with H
2 at 600 °C to reduce maghemite to magnetite. N
2 adsorption measurements showed that the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon. The adsorption isotherms of volatile organic compounds such as chloroform, phenol, chlorobenzene and drimaren red dye from aqueous solution onto the composites also showed that the presence of iron oxide did not affect the adsorption capacity of the activated carbon.
Two series of activated carbons have been prepared from date pits; series C, using carbon dioxide as activating agent, and series S, prepared by activation with steam under the same experimental ...conditions. The obtained samples were oxidized with nitric acid in order to introduce more oxygen surface groups. The surface area and porosity of the parent and oxidized activated carbons were studied by N
2 adsorption at 77
K and CO
2 adsorption at 273
K. The oxygen surface complexes were characterized by temperature-programmed decomposition (TPD). The results show that carbon dioxide and steam activations produce microporous carbons with an increasing amount of CO evolving groups when increasing the burn-off. On the other hand, oxidation with nitric acid increases the amount of CO and CO
2 evolved by the decomposition of surface oxygen groups, this increase being related to the development of porosity in the carbon with the degree of activation and to the activating agent used (CO
2 versus steam).
Abstract
Background
In addition to demonstrated public health benefits on reducing transmission, it remains unclear how early antiretroviral therapy (ART) must be started after acquisition of human ...immunodeficiency virus (HIV) to maximize individual benefits.
Methods
We conducted an open-label randomized clinical study in Lima, Peru among adult men who have sex with men and transgender women with acute (HIV-antibody negative/HIV-1 RNA positive) or recent (confirmed negative HIV-antibody or RNA test within 3 months) HIV infection, who were randomized to start ART immediately versus defer by 24 weeks. We evaluated outcomes by treatment arm and immunologic markers by days since estimated date of detectible infection (EDDI).
Results
Of 216 participants, 105 were assigned to immediate arm and 111 to deferred arm (median age 26.8 years, 37% with acute HIV). The incidence of non-ART-related adverse events was lower in immediate versus deferred arm (83 vs 123/100 person-years, IRR 0.67 (95% confidence interval CI .47, .95; P = .02), the difference dominated by fewer infections in those treated immediately. After 24 weeks of ART, between-group differences in CD4/CD8 cell ratio lessened (P = .09 overall), but differences between those initiating ART ≤ 30 days from EDDI (median 1.03, interquartile range IQR 0.84, 1.37), and those initiating > 90 days (0.88, IQR 0.61, 1.11) remained, P = .02. Principal components analysis of 20 immune biomarkers demonstrated distinct patterns between those starting ART > 90 days from EDDI versus those starting within 30 or 90 days (both P < .001).
Conclusions
To our knowledge, this is the only evaluation of randomized ART initiation during primary HIV and provides evidence to explicitly consider acute HIV in World Health Organization recommendations for universal ART.
Clinical Trials Registration
NCT01815580.
In this randomized study of 216 persons with primary HIV in Lima, Peru, those who began ART within 30 days of estimated date of infection experienced the fewest symptoms and had improved immune profiles compared to those starting ART later.
This work describes the devulcanization of vulcanized SBR (Styrene Butadiene Rubber) based on controlled oxidation with nitric acid. IR, ¹H and 13C-NMR, CHN elemental analyses, TG, GPC and TPD-MS ...(Temperature Programmed Decomposition-Mass Spectrometry) experiments suggest that nitric acid promotes two processes: (i) devulcanization by oxidation of the sulfide crosslinks and (ii) oxidation of the carbon framework leading to the formation of -COOH and -NO2 groups. Under aggressive conditions (HNO3, reflux) the polymer chain is strongly oxidized and fragmented to a highly oxygenated low molecular weight fraction, which is soluble in water.
ObjectivesThe COVID-19 pandemic has stimulated growing research on treatment options. We aim to provide an overview of the characteristics of studies evaluating COVID-19 treatment.DesignRapid scoping ...reviewData sourcesMedline, Embase and biorxiv/medrxiv from inception to 15 May 2021.SettingHospital and community care.ParticipantsCOVID-19 patients of all ages.InterventionsCOVID-19 treatment.ResultsThe literature search identified 616 relevant primary studies of which 188 were randomised controlled trials and 299 relevant evidence syntheses. The studies and evidence syntheses were conducted in 51 and 39 countries, respectively.Most studies enrolled patients admitted to acute care hospitals (84%), included on average 169 participants, with an average age of 60 years, study duration of 28 days, number of effect outcomes of four and number of harm outcomes of one. The most common primary outcome was death (32%).The included studies evaluated 214 treatment options. The most common treatments were tocilizumab (11%), hydroxychloroquine (9%) and convalescent plasma (7%). The most common therapeutic categories were non-steroidal immunosuppressants (18%), steroids (15%) and antivirals (14%). The most common therapeutic categories involving multiple drugs were antimalarials/antibiotics (16%), steroids/non-steroidal immunosuppressants (9%) and antimalarials/antivirals/antivirals (7%). The most common treatments evaluated in systematic reviews were hydroxychloroquine (11%), remdesivir (8%), tocilizumab (7%) and steroids (7%).The evaluated treatment was in favour 50% and 36% of the evaluations, according to the conclusion of the authors of primary studies and evidence syntheses, respectively.ConclusionsThis rapid scoping review characterised a growing body of comparative-effectiveness primary studies and evidence syntheses. The results suggest future studies should focus on children, elderly ≥65 years of age, patients with mild symptoms, outpatient treatment, multimechanism therapies, harms and active comparators. The results also suggest that future living evidence synthesis and network meta-analysis would provide additional information for decision-makers on managing COVID-19.
Membrane Introduction Mass Spectrometry (MIMS) was used to investigate chloroform degradation in acidic aqueous medium by sodium hypochloride (NaClO). From the experimental results a reaction ...sequence for the complete degradation of CHCl3 to CO2 and HCl was suggested. Furthermore, it was also proposed the formation of phosgene (COCl2) as a transient species under these experimental conditions.
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