Improved nanocomposite of montmorillonite and hydroxyapatite for defluoridation of water

A novel hydroxyapatite montmorillonite (HAP-MMT) nanocomposite system was synthesized using a simple wet chemical in situ precipitation method. Neat nano hydroxyapatite (HAP) was also synthesized for comparison. The characterization of the materials was carried out using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) isotherms to study the functional groups, morphology, crystallinity and the surface area respectively. Batch adsorption studies and kinetic studies on fluoride adsorption were conducted for the HAP-MMT system and for neat HAP. The effect of parameters such as contact time, pH, initial concentration, temperature, and thermodynamic parameters and the effect of coexisting ions on fluoride adsorption by HAP-MMT were studied. Results of the isotherm experiments were fitted to four adsorption isotherm models namely Langmuir, Freundlich, Temkin and Dubinin Radushkevich. Fluoride adsorption over HAP-MMT fitted to the Freundlich adsorption isotherm model and showed more than two-fold improved adsorption capacity (16.7 mg g−1) compared to neat HAP. The best-fitting kinetic model for both adsorbents was found to be pseudo second order. Calculated thermodynamic parameters indicated that the fluoride adsorption by HAP-MMT is more favorable compared to that on HAP within the temperature range of 27 °C–60 °C. Improved fluoride adsorption by HAP-MMT is attributed to the exfoliated nature of HAP-MMT. Gravity filtration studies carried out using a 1.5 ppm fluoride solution, which is closer to the ground water fluoride concentrations of Chronic Kidney Disease of unknown etiology (CKDu) affected areas in Sri Lanka, resulted in a 1600 ml g−1 break through volume indicating the potential of HAP-MMT to be used in real applications

Improving the Creation of Hot Spot Policing Patrol Routes: Comparing Cognitive Heuristic Performance to an Automated Spatial Computation Approach

Hot spot policing involves the deployment of police patrols to places where high levels of crime have previously concentrated. The creation of patrol routes in these hot spots is mainly a manual process that involves using the results from an analysis of spatial patterns of crime to identify the areas and draw the routes that police officers are required to patrol. In this article we introduce a computational approach for automating the creation of hot spot policing patrol routes. The computational techniques we introduce created patrol routes that covered areas of higher levels of crime than an equivalent manual approach for creating hot spot policing patrol routes, and were more efficient in how they covered crime hot spots. Although the evidence on hot spot policing interventions shows they are effective in decreasing crime, the findings from the current research suggest that the impact of these interventions can potentially be greater when using the computational approaches that we introduce for creating hot spot policing patrol routes

A NEW METHODOLOGY FOR DIAGNOSIS OF FANCONI ANEMIA BASED ON BIOLOGICAL DOSIMETRY

Fanconi Anemia (FA) is a syndrome associated with chromosomal fragility. Current laboratory tests to diagnose this disease are based on the scoring of chromosomal aberrations induced in peripheral blood lymphocytes by clastogenic chemical agents, mainly: diepoxybutane (DEB) or mitomycin C (MMC). This study evaluated an alternative test for the diagnosis of FA, in which ionizing radiation replaces DEB/MMC. Two groups were studied: normal and DEB-sensitive individuals. From each individual, samples of peripheral blood were irradiated using an electron linear accelerator. Following lymphocyte cultures, and slide preparation, metaphases were scored based on the same methodology for biological dosimetry, according to recommendations of the International Atomic Energy Agency. Our results emphasized a pattern of distribution of dicentrics, fragments, as well as abnormal chromosomal arrangements. The methodology of analysis here proposed permitted to distinguish normal from DEB-sensitive subjects

Total organic carbon and pyrolysis analysis of the Lower Cretaceous in Compton Bay and Atherfield, Isle of Wight (England)

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThe Wessex Basin (United Kingdom) includes hundreds of meters of Lower Cretaceous clays, silts, and sands deposited in a wide range of depositional environments. Studies have investigated these depositional systems from the organic matter (OM) perspective. However, questions remain concerning the composition, source, and the overall depositional constraints on the distribution of sedimentary OM in this area. Elemental (carbonate % and total organic carbon - TOC) and pyrolysis analyses were conducted on representative lithofacies of the Lower Cretaceous from the Wessex Basin at the Compton Bay and Atherfield sections, Isle of Wight. The highest TOC contents were determined in the upper part of the Ferruginous Sands and Sandrock formations. These elevated TOC intervals are associated with predominantly estuarine deposition. Except for one sample from the Vectis Formation, Hydrogen Index (HI) in all studied units is low and indicates Type IV kerogen assemblages, interpreted to be linked with strongly variable climates (with pronounced dry periods) and significant water table fluctuations in the source area and during transport. The one sample with a Type II-III kerogen assemblage from the lagoonal Vectis Formation supports previous studies which suggested that OM in the Vectis Formation varied vertically as a function of fluvial sediment and terrestrial organic matter input to the lagoonal environment with changes in salinity, sediment resuspension, and turbulence as a result controlling the abundance of dinoflagellate cysts

Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties.

Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol) (PVA) polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm) at a predetermined concentration (10% (w/w)), is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P < 0.05). In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues.Peer Reviewe

Stereology shows that damaged liver recovers after protein refeeding

Objective: The aim of the present study was to investigate the putative effects of a low-protein diet on the three-dimensional structure of hepatocytes and determine whether this scenario could be reversed by restoring the adequate levels of protein to the diet. Methods: Using design-based stereology, the total number and volume of hepatocytes were estimated in the liver of mice in healthy and altered (by protein malnutrition) conditions and after protein renutrition. Results: This study demonstrated a 65% decrease in the liver volume (3302 mm3 for the control for undernourished versus 1141 mm3 for the undernourished group) accompanied by a 46% reduction in the hepatocyte volume (8223 μm3 for the control for undernourished versus 4475 μm3 for the undernourished group) and a 90% increase in the total number of binucleate hepatocytes (1 549 393 for the control for undernourished versus 2 941 353 for the undernourished group). Reinstating a normoproteinic diet (12% casein) proved to be effective in restoring the size of hepatocytes, leading to an 85% increase in the total number of uninucleate hepatocytes (15 988 560 for the undernourished versus 29 600 520 for the renourished group), and partially reversed the liver atrophy. Conclusions: Awareness of these data will add to a better morphologic understanding of malnutrition-induced hepatopathies and will help clinicians improve the diagnosis and treatment of this condition in humans and in veterinary practice

Effect of voriconazole on Candida tropicalis biofilms: Relation with ERG genes expression

Candida tropicalis has emerged as the third most prevalent fungal pathogens and its ability to form biofilms has been considered one of the most important virulence factors, since biofilms represent high tolerance to antifungal agents. However, the mechanisms of C. tropicalis biofilm resistance to antifungals remain poorly understood. Thus, the main aim of this work was to infer about the effect of voriconazole on the formation and control of C. tropicalis biofilms and disclose its relationship with ERG genes' expression. Planktonic cells tolerance of several C. tropicalis clinical isolates to voriconazole was determined through of antifungal susceptibility test, and the effect of this azole against C. tropicalis biofilm formation and pre-formed biofilms was evaluated by cultivable cells determination and total biomass quantification. ERG genes expression was analyzed by quantitative real-time polymerase chain reaction. This work showed that C. tropicalis resistance to voriconazole is strain dependent and that voriconazole was able to partially control biofilm formation, but was unable to eradicate C. tropicalis pre-formed biofilms. Moreover, C. tropicalis biofilms resistance to voriconazole seems to be associated with alterations of sterol content in the cell membrane, resulting in ERG genes overexpression. Voriconazole is unable to control C. tropicalis biofilms, and the overexpression of ERG genes is a possible mechanism of biofilm resistance.TheauthorsthanktheFCTfortheStrategic Project of the UID/BIO/04469/2013 unit, FCT and European Union funds (FEDER/COMPETE) for the project RECI/BBBEBI/0179/2012 (FCOMP-01-0124-FEDER-027462). We also would like to acknowledge Pfizer , S.A. for the kindly donation of voriconazole