Modeling of Fixed Bed Adsorption Column Parameters of Iron(II) Removal Using Ferrihydrite Coated Brick

Fixed-bed operating experimental column conditions were studied to evaluate the performance of brick from Bangui Region (in Central African Republic), coated with iron oxyhydroxide (ferrihydrite) for the removal of iron(II) from aqueous solution. The prediction of theoretical breakthrough profiles using Bohart and Adams sorption model was employed to achieve characteristic parameters such as depth of exchange zone, time required for exchange zone to move vertically, moving rate for the exchange zone and adsorption capacity useful for fixed-bed column reactor was investigated under varying operating conditions. The effects of bed depth and flow rate on iron(II) adsorption were studied. Our finding revealed that the Brick from Bangui Region (in Central African Republic), coated with ferrihydrite was a very efficient media for the removal of Fe(II) ions from water. The experimental data showed that the depth and the moving rate (10.3 ± 0.6 cm) and (0.208 ± 0.006 cm/min) respectively of the exchange zone (adsorption zone) were independent of variability of the height of the adsorbent bed column, however the variations of the flow rate affect the moving rate of the exchange zone. The bed depth service time (BDST) model was used and permitted us to predict the service times of columns operated at various flow rates and bed depths and these predicted values were compared with the experimental values.

Local Drug Delivery Strategy for Cancer Treatment: Use of Biocompatible Sol-Gel-Derived Porous Materials

Porous silica xerogel materials have been developed to use as drug-release agents to be implanted directly in or near cancerous tissues. In order to test the capacity of the materials to absorb and then to release medicinal substances, a battery of examinations (UV and visible micro-Raman, porosity measurements, UV-visible absorption spectra) have been made using test drug molecules (clotrimazole, primaquine diphosphate and the anti-cancer agent vinblastine sulphate). Results show that the molecules can be post-doped into the gels and the Raman data provide indications of the best conditions for detecting the substances absorbed in the gels. Spectroscopic results show that the drug molecules are released by the xerogel over a period of 10 days. These results are promising for the development of these materials as drug-release agents.

In silico assessment of human health risks caused by cyanotoxins from cyanobacteria

Harmful algal blooms(HABs)that are formed by cyanobacteria have become a serious issue worldwide in recent years.Cyanobacteria can release a type of secondary metabolites called cyanotoxins into aquatic systems which may indirectly or directly provide health risks to the environment and humans.Cyanotoxins provide some of the most powerful natural poisons including potent neurotoxins,hepatotoxins,cytotoxins,and endotoxins that may result in environmental health risks,and long-term morbidity and mortality to animals and humans.In this research,we used the chemcomputational tool Molinspiration for molecular property predictions,Pred-hERG 4.2 web software for cardiac toxicity prediction,and Pred-Skin 2.0 web software for predicting skin sensitization.We are predicting some toxicological aspects of cyanobacteria here using chemcomputational tools with the hypothesis that cyanotoxins are providing a risk to human health.We are using the tool Pred-hERG 4.2 to predict hERG channel blocking potential and the Pred-skin tool to predict skin sensitization due to cyanotoxins.The potential of anatoxin,ambigol,the microcystin group,and lyngbyatoxin A,lyngbyatoxin B,nodularin-R,and saxitoxin were predicted to cause skin sensitization in the final results(consensus model).Anatoxin-a and lyngbyatoxin were predicted to allow GI absorption and blood–brain barrier penetration.Among the 20 predicted cyanotoxins only aeruginosin 103-A,ambigol A,and ambigol were predicted by Pred-hERG 4.2 according to the applicability domain results as potential cardiotoxins with weak or moderate potency.Lyngbyatoxin shows activity through the GPCR ligand and protease,kinase,and enzyme inhibitor.

Chemometric analysis of femtosecond transient absorption spectroscopy data:Study of the photochromism of anils

Chemometric methods are applied for the purpose of extracting relevant information from transient absorption spectroscopy data probing the photochromism of molecules from the family of salicylidene aniline. The process consists of an ultrafast excited state intramolecular proton transfer occurring from an enol form which is then followed by a cis-trans isomerization to finally reach a trans-keto photo-product. This work focuses on the potential of combining multivariate curve resolution for modeling pure profiles and two dimensional correlation spectroscopy data analysis for providing information on the dynamics of spectral features. The results obtained for one derivative of salicylidene aniline provide information regarding the number of species created after the proton transfer and characterization of their absorption spectra and their kinetics in the picosecond time scale. The spectral resolution of two cis-keto* forms is proposed for the first time. It is also found that both cis-keto* species are involved in the formation of the trans-keto photo-product. The main precursor of the trans-keto photo-product is the cis-keto* form which has the shortest characteristic time.

A Perspective on Data Processing in Super-resolution Fluorescence Microscopy Imaging

With super-resolution microscopy,we attempt to visualize(biological)structures and processes at the sub-cellular level(i.e.,nanoscale).To obtain this information,the samples are labeled with fluorophores that have a stochastic on/off switching of their emissions,which help to overcome the optical diffraction limit of around 250 nm,related to the use of optical micro-scopes.However,nowadays,research focuses on the imaging of live cells and thicker samples.These investigations require a high amount of simultaneously active fluorophores(i.e.,high-density imaging)and are challenging due to the collapse of the single-molecule localization techniques and the increased background in the image.Therefore,recent efforts have shifted towards the development of new ways to process the data.This publication gives an introduction to wide-field super-resolution fluorescence microscopy,explaining the concepts of the technique,and then gives an overview of the recently developed methods to provide super-resolution images for high-density data of live cells and ways to overcome the issues related to the imaging of these samples.