Self‐aggregated nanoparticles of N‐dodecyl,N′‐glycidyl(chitosan) as pH‐responsive drug delivery systems for quercetin

In this study, pH‐responsive amphiphilic chitosan (CS) nanoparticles were used to encapsulate quercetin (QCT) for sustained release in cancer therapy. The novel CS derivatives were obtained by synthesis with 2,3‐epoxy‐1‐propanol, also known as glycidol, followed by acylation with dodecyl aldehyde. Characterization was performed by spectroscopic, viscosimetric, and size‐determination methods. Critical aggregation concentration, morphology, entrapment efficiency, drug release profile, cytotoxicity, and hemocompatibility studies were also carried out. The average size distribution of the self‐assembling nanoparticles measured by dynamic light scattering ranged from 140 to 300 nm. In vitro QCT release and Korsmeyer–Peppas model indicated that pH had a major role in drug release. Cytotoxicity assessments indicated that the nanoparticles were non‐cytotoxic. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay further revealed that QCT‐loaded nanoparticles could inhibit MCF‐7 cell growth. In vitro erythrocyte‐induced hemolysis indicated the good hemocompatibility of the nanoparticles. These results suggest that the synthesized copolymers might be potential carriers for hydrophobic drugs in cancer therapy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45678.     

Valuation of the historic environment: The scope for using economic valuation evidence in the appraisal of heritage-related projects

In this paper we consider the question, ‘What is the the scope for using results of economic valuation studies in the appraisal and assessment of heritage-related projects and programmes?’ This entails assessing the potential role and scope of ‘value transfer’, which is an approach to economic valuation that uses results of previous valuation studies (for example, travel cost or stated preference studies) in the appraisal of projects and programmes. A distinct appeal of value transfer is its expediency and value for money properties in relation to commissioning original valuation studies, which can enable greater use of economic values within decision making. Its potential role in the appraisal of heritage assets depends on whether it is deemed a reliable approach to economic valuation, and whether there is a sufficient body of economic valuation literature concerning the heritage sector. Correspondingly, we examine: (i) the applicability of economic valuation to the historic environment; (ii) the basis for value transfer; and (iii) the literature pertaining to the valuation of the historic environment. We also develop a case study, which demonstrates the use of value transfer in a heritage context. Overall there currently appears to be limited scope for value transfer applications in heritage-related appraisal and evaluation exercises. This is in part due to the heterogeneity and complexity of heritage assets. However, a more fundamental constraining factor is the current extent of heritage valuation literature; only 30 valuation studies were identified relating to the historic environment. We recommend that future work focuses on developing a database of valuation studies relating to the heritage sector, and on establishing a broader base of high-quality original heritage-related economic valuation studies. Moreover, where value transfer is applied in an appraisal and evaluation context to heritage assets, much emphasis should be placed on satisfying the criteria for identifying suitable valuation evidence from existing studies.     

Industrial effluents and surface waters genotoxicity and mutagenicity evaluation of a river of Tucuman, Argentina

Assessment of water pollution and its effect upon river biotic communities and human health is indispensable to develop control and management strategies. The aim of this work was to ascertain the biotoxicity of water pollution in samples from industrial effluent discharge areas of Tucumán, Argentina by means of biological tests. Chemical characterization of the water pollution was verified by measuring dissolved oxygen concentration or levels of suspended matter and salts. Genotoxic/mutagenic potential was determined using Allium anaphase-telophase and Ames/Salmonella tests. All samples were phytotoxic and genotoxic for Allium roots. Micronucleus and anaphase aberrations were observed, but they did not show mutagenic effects on Salmonella typhimurium, TA98 and TA100 strains with and without metabolic activation (S9). Our results show the importance of testing industrial effluents by chemical methods and complementary biological tests to optimize the control policy on these environmental samples.     

Consequence analysis to determine the damage to humans from vapour cloud explosions using characteristic curves

The aim of this paper is to provide a methodology to facilitate consequence analysis for vapour cloud explosions (VCE). Firstly, the main PROBIT equations to evaluate direct damage on humans from those accidents (eardrum rupture, death due to skull fracture, death due to whole body impact and lung damage) are discussed and the most suitable ones are selected. Secondly, a new methodology is developed to relate characteristic overpressure-impulse-distance curves for VCE, obtained in a previous paper (F. Diaz Alonso et al., Characteristic overpressure-impulse-distance curves for vapour cloud explosions using the TNO Multi-Energy model, J. Hazard. Mater. A137 (2006) 734-741) with the selected PROBIT equations. This methodology allows the determination of damage as a function of distance to the accident's origin in only one step, using explosion energy and VCE Multi-Energy charge strength as input parameters.     

Assessing methods for blood cell cytotoxic responses to inorganic nanoparticles and nanoparticle aggregates

Inorganic nanoparticles (NPs) show great potential for medicinal therapy. However, biocompatibility studies are essential to determine if they are safe. Here, five different NPs are compared for their cytotoxicity, internalization, aggregation in medium, and reactive oxygen species (ROS) production, using tumoral and normal human blood cells. Differences depending on the cell type are analyzed, and no direct correlation between ROS production and cell toxicity is found. Results are discussed with the aim of standardizing the procedures for the evaluation of the toxicity.     

Indirect electrochemical oxidation of cyanide by hydrogen peroxide generated at a carbon cathode

The oxidation of cyanide was performed in aqueous sodium hydroxide solutions. Cyanide was oxidized over 90% to cyanate by hydrogen peroxide electrochemically generated at a 60 ppi reticulated vitreous carbon electrode from oxygen reduction. Cyanide depletion was recorded as a function of time from the analysis of cyanide based on the titration procedure using silver nitrate with p$p$-dimethylamino-benzal-rhodanine indicator. Cyanate was further oxidized to mineralization by decreasing the pH of the solution obtaining a recovery of carbon dioxide over 90%. The employment of copper together with hydrogen peroxide to increase the destruction of cyanide was also studied. Different molar ratios of hydrogen peroxide/cyanide and copper/cyanide were tested achieving over 98% of cyanide destruction in a time period of 40 min by increasing either the concentration of hydrogen peroxide or copper ion.     

Fatty acid composition, extraction, fractionation, and stabilization of bullfrog (Rana catesbeiana) oil

The oil extracted from the fat-storage organ (fat body) of the bullfrog (Rana catesbeiana) was characterized for its fatty acid composition. The main fatty acids were palmitic (18.1%), stearic (4.1%), myristic (2.7%), oleic (31.7%), and linoleic (12.9%) acids. Long-chain polyunsaturated fatty acids were also present in significant amounts, i.e., eicosapentaenoic (1.5%) and docosahexaenoic (4.7%), and were probably derived from the fish meal content of the diet. A partially fractionated oil was extracted from the homogenized and frozen fat body with an oleic acid content of 43.2%. The natural alkaloid boldine, added at 0.5 mg/g oil level, improved the oxidative stability by a factor ranging from 1.7 to 2.4, as assessed by the Oil Stability Index method between 90 and 110°C. The stabilization effect of boldine was higher than that of naringenin, morin, and quercitin and for the synthetic antioxidant butylated hydroxytoluene at the same concentration level.     

Structural evaluation of copolymers of ethylene and 1‐octadecene by using the temperature rising elution fractionation technique

Three samples of ethylene‐octadecene copolymers having different quantitative composition were analyzed structurally and in terms of their thermal behavior. The samples were fractionated by temperature rising elution fractionation, presenting different chemical composition distributions (CCD) that are essentially the result of the proportion of incorporated octadecene. The CCD profiles were relatively wide for samples generated by metallocene catalysts. The analyses of the fractions showed that the melting and crystallization temperatures decrease with increasing comonomer incorporation, but this relation is affected by the average molecular weight of the chains. The melting thermograms of those fractions having higher proportions of octadecene may be divided into two characteristic regions: the first one, at a higher temperature, originates from the melting of the least modified chains, which crystallize more perfectly. The second one is formed by the melting of chains having a high degree of comonomer incorporation, which melt in a diffuse manner over a wide range of temperatures. It is probable that the morphology of the crystals formed in this region does not follow the folded chain model, and are better represented by a model involving the alignment of chain segments (bundling). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 221–227, 2001