COVAD survey 2 long-term outcomes: unmet need and protocol

Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups

Preparation and characterizations of activated carbon from kenaf fiber for equilibrium adsorption studies of copper from wastewater

The potential of activated carbon prepared from kenaf fiber (KF) to remove copper (II) from aqueous effluents was investigated. The fibers were first semi-carbonized, then impregnated with potassium hydroxide (KOH) and finally activated by using carbon dioxide (CO 2) gas to produce activated carbon. Pore structure and physical characteristics of the prepared kenaf fiber activated carbon (KFAC) were determined. Adsorption studies for divalent copper (Cu) ions were carried out to delineate the effect of contact time, temperature, pH and initial metal ion concentration on equilibrium adsorption capacity. The experimental data followed pseudo-second-order kinetics and Elovich Model than pseudo-first-order. Langmuir, Freundlich and Temkin models were implemented to analyze the parameters for adsorption at 30 °C, 50 °C and 70 °C. Thermodynamic parameters such as ΔG o, ΔH o and ΔS o which represent Gibbs free energy, enthalpy and entropy, respectively, were evaluated. It was concluded that activated carbon from kenaf fiber (KFAC) can be used as an efficient adsorbent for removal of Cu (II) from synthetic wastewater. © 2012 Korean Institute of Chemical Engineers, Seoul, Korea

Carbon nanotube membranes for water purification: A bright future in water desalination

10.1016/j.desal.2013.12.026Desalination336197-109DSLN

Catalytic Isolation and Physicochemical Properties of Nanocrystalline Cellulose (NCC) using HCl-FeCl3 System Combined with Ultrasonication

This research emphasizes the isolation of nanocrystalline cellulose (NCC) from palm tree cellulose (PTC) and α-cellulose (AC), using acidic FeCl3-assisted catalytic pretreatment coupled with ultrasonication. The cavitation effect of ultrasonication affects the microstructure of the fibers, ultimately enhancing the crystallinity index of the prepared nanocrystalline cellulose (NCC) sample. In this research, Fourier transform infrared spectroscopy (FTIR) was used to identify the specific functional groups on both types of NCC sample. X-ray diffraction (XRD) analysis demonstrated that the isolated NCC from PTC and AC showed a higher crystallinity index of 73.51% and 89.03%, with diameters of 20 to 70 nm and 15 to 50 nm, respectively. The change in surface morphological features was observed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopic (TEM) analysis. It was observed that PTC-based NCC had higher thermal stability than the starting cellulosic sample, whereas NCC isolated from AC showed an opposite trend of reduced thermal stability relative to the raw sample. The results indicated that catalytic acid hydrolysis with ultrasonication was able to yield up to 80.88% and 81.20% of NCC from PTC and AC, respectively, which is comparatively high enough for economic viability of the process

Batch and fixed bed adsorption studies of lead (II) cations from aqueous solutions onto granular activated carbon derived from mangostana garcinia shell

The feasibility of granular activated carbon (GAC) derived from Mangostene (Mangostana garcinia) fruit shell to remove lead, Pb 2+ cations was investigated in batch and fixed bed sorption systems. Batch experiments were carried out to study equilibrium isotherms, kinetics, and thermodynamics by using an initial lead (Pb 2+ ions) concentration of 50 to 100 mg/L at pH 5.5. Equilibrium data were fitted using Langmuir, Freundlich, and Temkin linear equation models at temperatures 30°C, 50°C, and 70°C. Langmuir maximum monolayer sorption capacity was 25.00 mg/g at 30°C. The experimental data were best represented by pseudo-second-order and Elovich models. The sorption process was found to be feasible, endothermic, and spontaneous. In column experiments, the effects of initial cation concentration (50 mg/L, 70 mg/L, and 100 mg/L), bed height (4.5 cm and 3 cm), and flow rate (1 mL/min and 3 mL/min) on the breakthrough characteristics were evaluated. Breakthrough curves were further analyzed by using Thomas and Yoon Nelson models to study column dynamics. The column was regenerated and reused consecutively for four cycles. The result demonstrated that the prepared activated carbon was suitable for removal of Pb 2+ from synthetic aqueous solution using batch, as well as fixed bed sorption systems

Application of response surface methodology (Rsm) for optimizing production condition for removalof Pb (Ii) and Cu (Ii) onto kenaf fiber based activated carbon

This research aims to find out the feasibility of preparing kenaf fiber based carbon for removal of divalent cations of Pb (II) and Cu (II) from waste water. Activated carbon was prepared by using physiochemical activation method which involves two step of potassium hydroxide impregnation (KOH) with carbon dioxide activation of the semi carbonized char. The effects of three preparation variables; temperature (500-700°C), time (1-3 h) and Impregnation Ratio (IR) by using KOH (1-3) on the removal percentage of Pb (II) and Cu (II) ions were investigated by using Design of Experiment (DOE). Quadratic models were developed to correlate activated carbon preparation variables from kenaf fibers with the two responses by applying Central Composite Design (CCD). Experimental data were analysed by using analysis of variance (ANOVA) and the most influential factor on each experimental design response was identified. Process optimization was done by validating both the model to obtain maximum removal efficiency with possible maximum yield of activated carbon. © Maxwell Scientific Organization, 2012

High yield super-hydrophobic carbon nanomaterials using cobalt/iron co-catalyst impregnated on powder activated carbon

Synthesis of super-hydrophobic carbonaceous materials is gaining a broader interest by the research community due to its versatile application in separation processes, special coating technologies, and membrane distillation. Carbon nanomaterials (CNMs) may exhibit stable super-hydrophobic character due to their unique physio-chemical features which can be further controlled based on customer requirements by optimizing the process variables. This study deals with the application of a bimetallic catalyst composed of iron (Fe) and cobalt (Co) to synthesize CNMs from powder activated carbon as a precursor. The process parameters were optimized to ensure super-hydrophobic surfaces. Chemical vapor deposition was utilized for the growth of carbon nanomaterials. The impact of input variables on the desired output of yield and contact angle was analyzed. The chemical vapor deposition process was optimized using the response surface methodology based on Box-Behnken design. The proportion of the catalysts and reaction time were the three input explanatory variables whereas the desired response variables were selected as the carbon yield (CY) and contact angle (CA). The synthesized super-hydrophobic materials were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Raman spectroscopy, thermogravimetric analysis (TGA), and contact angle analysis. The comprehensive statistical study of the results led to a significant model and optimization. The highest CY (351%) and CA (173◦ ) were obtained at the optimal loading of 2.5% Fe and 2% Mo with a reaction time of 60 min. The images obtained from FESEM and TEM revealed the presence of two types of CNMs including carbon nanofibers and multiwall carbon nanotubes. Thermogravimetric analysis was carried out to observe the temperature degradation profile of the synthesized sample. Raman spectroscopic analysis was also used to observe the proportion of ordered and disordered carbon content inside the synthesized samples. The improved catalytic super-hydrophobic carbon nanostructured materials production process proposed by this study assures the stability and high yield of the product. © 2021 by the authors. Li-censee MDPI, Basel, Switzerland

Application of response surface methodology (Rsm) for optimizing production condition for removalof Pb (Ii) and Cu (Ii) onto kenaf fiber based activated carbon

This research aims to find out the feasibility of preparing kenaf fiber based carbon for removal of divalent cations of Pb (II) and Cu (II) from waste water. Activated carbon was prepared by using physiochemical activation method which involves two step of potassium hydroxide impregnation (KOH) with carbon dioxide activation of the semi carbonized char. The effects of three preparation variables; temperature (500-700°C), time (1-3 h) and Impregnation Ratio (IR) by using KOH (1-3) on the removal percentage of Pb (II) and Cu (II) ions were investigated by using Design of Experiment (DOE). Quadratic models were developed to correlate activated carbon preparation variables from kenaf fibers with the two responses by applying Central Composite Design (CCD). Experimental data were analysed by using analysis of variance (ANOVA) and the most influential factor on each experimental design response was identified. Process optimization was done by validating both the model to obtain maximum removal efficiency with possible maximum yield of activated carbon. © Maxwell Scientific Organization, 2012

Preparation and investigation of photoelectrochemical behaviour of Ce and W co-doped TiO2 composite film

Cerium and tungsten co-doped TiO2 photocatalyst composite material has been fabricated by using a facile sol-gel method. The composite was coated on ITO film via electrophoretic deposition method. In order to understand the morphology, structure and optical properties, the composite material was characterized with X-ray diffraction, scanning electron microscope, UV-vis and Fourier transform infrared spectroscopy. The results showed a uniformly distributed porous composite film on ITO substrate. Cerium and tungsten as oxides are dispersed on the substrate. A significant photocurrent was developed under solar simulator irradiation and the value was observed higher as compared with pure TiO2 film electrodes

Diversidad de las violencias. Equidades y jerarquías entre jóvenes “en conflicto con la ley”

En este artículo me propongo reflexionar sobre el carácter diverso y complejo de los vínculos que se tejen cotidianamente en los institutos correccionales, en donde las dicotomías violento-no violento deben ser matizadas para dar paso a las ambigüedades que articulan dichas relaciones. Se analiza así, el modo en que los jóvenes construyen lazos sociales y clasifican a las personas que las rodean en relación a criterios de equidad y jerarquía, que revelan diversos significados de las violencias.In this article I propose to think on the diverse and complex carácter of the links that are woven daily in the correctional institutes, where the dichotomies violent-not violent must be tinted to give step to the ambiguities that articulate the above mentioned relations. It is analyzed this way, the way in which the young men contruct social bows and classify the persons who surround them in relation to creiteria of equito and hierarchy, which reveal the diverse meaning of violences.Fil: Tedesco, Graciela. Universidad Nacional de Córdoba. Museo de Antropología. Núcleo de Estudios de Violencia; Argentin