Evaluation of candidate biocides to control the biofouling Asian clam in the drinking water treatment industry: An environmentally friendly approach

The biofouling Asian clam Corbicula fluminea greatly affects freshwater-dependent facilities in Europe and North America, including in the Great Lakes region. As chlorination has become increasingly restricted, finding alternative control agents is a priority. Due to the species' epifaunal nature, the body of knowledge on Dreissena polymorpha is larger than that on the Asian clam, and there is a tendency to assume that mitigation methods should work similarly for both species. However, this generalisation is inaccurate, and the optimisation of Asian clam control relies on species-specific toxicological data. This paper reports information on the potential of three candidate biocides for C. fluminea control: (i) the cationic polydiallyldimethylammonium chloride (polyDADMAC), (ii) potassium chloride and (iii) aluminum sulphate. While these chemicals may be employed in a range of contexts, they are particularly suitable for the highly regulated drinking water industry. LT₅₀ values ranging from 284.3 h, for polyDADMAC applied at 10 mg/L, to 855.1 h, for an aluminum sulphate concentration of 11 mg/L, were obtained. Ecotoxicological standard tests with Pseudokirchneriella subcapitata and Daphnia magna suggested that, amongst the three biocides, potassium chloride is the one representing lower potential environmental hazard (with, for example, 48 h-EC₅₀ higher than 1 g/L for Daphnia immobilisation, which compares to values of 20.2 and 112.5 mg/L for polyDADMAC and aluminum sulphate, respectively). The three chemicals are promising control agents at dosages compatible with waterworks' operational requirements with polyDADMAC having the highest biocidal activity, but also posing more environmental risks.     

Adhesion of Listeria monocytogenes to materials commonly found in domestic kitchens

The aim of this work was to investigate the adhesion of Listeria monocytogenes ATCC 15313 to glass, granite, marble, polypropylene from a bowl (PPb), polypropylene from a cutting board (PPcb) and stainless steel (SS), which are materials commonly used in kitchens. Marble and granite were chosen because they are applied as kitchen bench covers and pavements in many countries and there are no literature reports on their behaviour in terms of microbial adhesion. The effect of surface hydrophobicity and roughness on the adhesion process was also analysed. The results showed that the highest extent of adhesion of L. monocytogenes occurred to stainless steel, followed by glass and in less extent to the other materials studied. However, it was not possible to establish a correlation between surface hydrophobicity or roughness and the extent of adhesion of L. monocytogenes . The adherence of L. monocytogenes should be dependent on other factors, like the presence of exopolymers and surface charge.     

YEAST FLOCCULATION: A NEW METHOD FOR CHARACTERISING CELL SURFACE INTERACTIONS

Flocculation is a property of yeast cells that has been traditionally used in industrial fermentations, especially in the brewing and wine industries. It is a cell wall interaction and an increase in flocculation is strongly correlated with an increase in cell surface hydrophobicity . Methods to assay yeast cell surface hydrophobicity are only qualitative and while electrostatic interactions can play an important role, they are not always taken into account . In this work, a simple and accurate method based on contact angle measurements is described to determine yeast cell surface hydrophobicity. With this method, it is possible to quantify yeast cell surface hydrophobicity by determining the free energy of interaction between cells and water molecules. Several yeast strains with different flocculation characteristics have been used to validate the method .     

Influence of anthocyanins and derivative pigments from blueberry (Vaccinium myrtillus) extracts on MPP intestinal uptake: A structure–activity approach

The aim of the present study was to investigate the influence of an anthocyanin extract (extract I), and two other derivative extracts (extracts II and III), which are being developed aiming to be further applied in the food industry, on intestinal uptake of organic cations. For this purpose, the effect of these compounds on ³H-MPP⁺ uptake was evaluated in Caco-2 cells (an enterocyte-like cell line derived from a human colonic adenocarcinoma).     

家庭住宅 法国拉马蒂埃尔

正几个世纪以来,不同的地理环境一直都采用这类封闭的庭院形式——每一次都根据当地气候、风俗习惯和建筑实践进行改造。作为一种在建筑物内捕捉户外景观的手段,庭院由建筑内部结构决定。流畅的庭院不但提供内外部隐私保护,而且也不断地向外延伸,积极融入周边景观。该住宅遵守严格的分区指导方针,同时通过在屋顶上扩建自然植物区系与景观融合。坐落在橄榄树林、松树和葡萄园内,该住宅充分利用坡地,从而获得可持续的拓展和种植     

Application of the Nernst-Planck approach to lead ion exchange in Ca-loaded Pelvetia canaliculata

Ca-loaded Pelvetia canaliculata biomass was used to remove Pb²⁺ in aqueous solution from batch and continuous systems. The physicochemical characterization of algae Pelvetia particles by potentiometric titration and FTIR analysis has shown a gel structure with two major binding groups - carboxylic (2.8 mmol g⁻¹) and hydroxyl (0.8 mmol g⁻¹), with an affinity constant distribution for hydrogen ions well described by a Quasi-Gaussian distribution. Equilibrium adsorption (pH 3 and 5) and desorption (eluents: HNO₃ and CaCl₂) experiments were performed, showing that the biosorption mechanism was attributed to ion exchange among calcium, lead and hydrogen ions with stoichiometry 1:1 (Ca:Pb) and 1:2 (Ca:H and Pb:H). The uptake capacity of lead ions decreased with pH, suggesting that there is a competition between H⁺ and Pb²⁺ for the same binding sites. A mass action law for the ternary mixture was able to predict the equilibrium data, with the selectivity constants α_Ca^H = 9 ± 1 and α_Ca^Pb = 44 ± 5, revealing a higher affinity of the biomass towards lead ions. Adsorption (initial solution pH 4.5 and 2.5) and desorption (0.3 M HNO₃) kinetics were performed in batch and continuous systems. A mass transfer model using the Nernst-Planck approximation for the ionic flux of each counter-ion was used for the prediction of the ions profiles in batch systems and packed bed columns. The intraparticle effective diffusion constants were determined as 3.73 × 10⁻⁷ cm² s⁻¹ for H⁺, 7.56 × 10⁻⁸ cm² s⁻¹ for Pb²⁺ and 6.37 × 10⁻⁸ cm² s⁻¹ for Ca²⁺.     

A new vinylpyranoanthocyanin pigment occurring in aged red wine

A new pyranoanthocyanin–vinylphenol pigment was detected in an aged Port red wine. The UV–Vis spectrum of this pigment was found to have a λ_max of 538 nm that is bathochromically shifted from that of original anthocyanins, exhibiting a more purple hue in acidic solution. This newly formed pigment was synthesized in model solution through the reaction between malvidin 3-O-glucoside–pyruvic acid adduct and vinylphenol and its structure was assigned by NMR and mass spectrometry. This pigment is reported herein for the first time.     

Transition from screen-film to computed radiography in a paediatric hospital: the missing link towards optimisation

In paediatrics, the risks associated with ionising radiation should be a major concern, due to children's higher susceptibility to radiation effects. Measure entrance skin dose (ESD) in chest and pelvis X-ray projections and compare the results with the 'European guidelines on quality criteria for diagnostic radiographer images in paediatrics' in order to optimise radiological practice. ESD values were obtained using an ionisation chamber Diamentor M4 KDK (PTW) in 429 children, who underwent chest X-ray or pelvis X-ray in a Computed Radiography system. In the first phase of the study, data were collected according to protocols used in the department; in a second phase different tube voltage values were used according to patient weight. A third phase was carried out, only for chest X-ray, using the exposure parameters of phase 2, plus activating lateral ionisation chamber. Three paediatric radiologists blindly assessed image quality of chest X-ray, using a validated assessment available in the 'European guidelines on quality criteria for diagnostic radiographer images in paediatrics'. Considering all the patients submitted to chest X-ray, the average ESD was 0.22, 0.16 and 0.08 mGy, for phases 1, 2 and 3, respectively. For pelvis X-ray, the average ESD decreased from 1.18 mGy in phase 1 to 0.78 mGy in phase 2. Dose optimisation was achieved. ESD was reduced 63.6 and 33.9 % in chest and pelvis X-ray, respectively.     

Towards a conceptualisation of quality in information technology projects

Quality has been extensively studied in repetitive operations, but it remains under-researched in projects. The uncertainty and dynamics of projects challenge the principles of quality developed for repetitive operations, and call for project-tailored solutions. This article explores the attributes of quality in projects, based on interviews conducted within a large IT-services company. An adapted repertory grid was used to investigate the understanding of quality by comparing concrete examples of projects considered as high or low quality. Eight attributes of quality were identified, which indicate a tension between a mechanistic standpoint of quality, and the need to incorporate less tangible aspects.