Role of dense shelf water cascading in the transfer of organochlorine compounds to open marine waters

Settling particles were collected by an array of sediment trap moorings deployed along the Cap de Creus (CCC) and Lacaze-Duthiers (LDC) submarine canyons and on the adjacent southern open slope (SOS) between October 2005 and October 2006. This array collected particles during common settling processes and particles transferred to deep waters by dense shelf water cascading (DSWC). Polychlorobiphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlorobenzenes (CBzs)--pentachlorobenzene and hexachlorobenzene--and hexachlorocyclohexanes were analyzed in all samples. The results show much higher settling fluxes of these compounds during DSWC than during common sedimentation processes. The area of highest deposition was located between 1000 and 1500 m depth and extended along the canyons and outside them showing their channelling effects but also overflows of dense shelf water from these canyons. Higher fluxes were observed near the bottom (30 m above bottom; mab) than at intermediate waters (500 mab) which is consistent with the formation and sinking of dense water close to the continental shelf and main displacement through the slope by the bottom. DSWC involved the highest settling fluxes of these compounds ever described in marine continental slopes and pelagic areas, e.g., peak values of PCBs (960 ng · m(-2) · d(-1)), DDTs (2900 ng · m(-2) · d(-1)), CBzs (340 ng · m(-2) · d(-1)) and lindane (180 ng · m(-2) · d(-1)).     

Competitive binding of Cd and Zn with the phytochelatin (gamma-Glu-Cys)4-Gly: comparative study by mass spectrometry, voltammetry-multivariate curve resolution, and isothermal titration calorimetry

The competitive binding of Cd2+ and Zn2+ by the phytochelatin (gamma-Glu-Cys)4-Gly (PC4) has been examined using several techniques. Electrospray ionization mass spectrometry is used to determine the stoichiometries of the complexes, while voltammetric data analyzed by multivariate curve resolution with alternating least squares allows one to not only trace the displacement induced by Cd2+ or Zn2+ in the binding of Zn2+ or Cd2+, respectively, by PC4, but also to obtain a complete overview of the processes involved. Isothermal titration calorimetry is used to determine the related binding and thermodynamic parameters. Results obtained via these different techniques are compared and discussed below. The formation of ternary CdZn(PC4) and Cd2Zn(PC4) complexes was observed.     

Electroflottation et desinfection simultanee d'eaux residuaires urbainesSimultaneous electroflotation and disinfection of sewage

This reports presents the results of a simultaneous electroflotation and disinfection sewage treatment, after chemical coagulation and flocculation and in the presence of chloride ions at various concentrations. Theoretical studies had shown that anodic oxidation of chloride ions gives hyperchlorites (for pH 7.5) together with (if sufficient potential is provided) oxygen. A dynamic study was thus achieved. It appeared that for a given chloride concentration the chlorine production linearly increases with the current density and depends on the organic load (COD) and oxidation potential of the effluent (Figs 6, 7 and 8). The performances of the process were studied in the continuous mode on a small pilot plant, after treatment of the effluent with ferric chloride and an organic polymer (Fig. 2). In all experiments current density and chloride concentration were raised (respectively 100, 200, 300 A m^?2 and from 300 to 3000 mg l^?1). The results obtained showed that solid-liquid separation was improved over static clarification for 2 h (Table 3) and the disinfection efficiency was equal or better than that obtained with gaseous chlorine (Table 4, Fig. 9). For example at a 900 mg l^?1 chloride concentration the three current density used give treated water containing less than 10³/100 ml total coliforms (initial concentration 4.7 · 10⁷/100 ml). These results have direct applications to the design of electroflotation units where a better plug flow should be sought. Moreover this process produces highly concentrated sludges. The utilization of ATP (Adenosine Triphosphate) as an indicator of the viability of a biomass showed that the process is applicable to activated sludges with recycling. The experimental conditions required for this application are still uncertain and require further study.     

Assessing concerns of interested parties when predicting the significance of environmental impacts related to the construction process of residential buildings

The most common challenges and obstacles encountered by construction organizations during the process of implementing and using environmental management systems are related to the inherent peculiarities of the construction sector. Several studies have shown that one of the issues involving the greatest level of uncertainty is the identification and assessment of environmental impacts. In order to improve the identification of the significance of environmental impacts of construction projects and sites, which will lead to greater efficiency and robustness in environmental management systems, this paper extends the systematic approach for identifying and assessing potential adverse environmental impacts at the pre-construction stage presented in Gangolells et al. (2009) by introducing the assessment of the concerns of interested parties. By considering concerns amongst internal and external interested parties, one can assess the significance of environmental impacts taking into account not only the severity of the impacts but also local perceptions and international challenges, thereby ensuring that the determination of the impacts’ significance is appropriate to the particular socioeconomic and biophysical environments surrounding construction sites. In order to quantitatively measure concerns among internal and external interested parties for each of the 37 environmental impacts related to a construction project, we developed corresponding indicators and assessment scales with the help of a panel of experts. A series of χ² tests conducted over 76 new-start construction projects clearly revealed that the severity of environmental impacts is not correlated with the concerns of interested parties. The development of a formal quantitative method and the subsequent definition of a threshold make it possible to obtain advance knowledge of the significance – and, therefore, the acceptability – of each potential environmental impact for a particular construction project. A total score for each construction project alternative is also obtained, so the improved methodology provides a consistent basis for comparing construction companies and construction sites. Finally, two case studies are presented in order to demonstrate the benefits of the improved methodology.     

Dynamic analysis of structures using a Reissner-Mindlin finite strip formulation

In this paper a finite strip formulation based on Reissner-Mindlin plate theory for dynamic analysis of prismatic shell type structure is presented. Detailed expressions of the relevant strip matrices for a variety of structures using the simple two node linear strip element are given. Examples of the good performance of the linear strip element for free and forced vibration analysis of plates, bridges and axisymmetric shells are presented.     

Microorganism identification by matrix-assisted laser/desorption ionization mass spectrometry and model-derived ribosomal protein biomarkers

An improved data analysis method is described for rapid identification of intact microorganisms from MALDI-TOF-MS data. The method makes no use of mass spectral fingerprints. Instead, a microorganism database is automatically generated that contains biomarker masses derived from ribosomal protein sequences and a model of N-terminal Met loss. We quantitatively validate the method via a blind study that seeks to identify microorganisms with known ribosomal protein sequences. We also include in the database microorganisms with incompletely known sets of ribosomal proteins to test the specificity of the method. With an optimal MALDI protocol, and at the 95% confidence level, microorganisms represented in the database with 20 or more biomarkers (i.e., those with complete or nearly completely sequenced genomes) are correctly identified from their spectra 100% of the time, with no incorrect identifications. Microorganisms with seven or less biomarkers (i.e., incompletely sequenced genomes) are either not identified or misidentified. Robustness with respect to variations in sample preparation protocol and mass analysis protocol is demonstrated by collecting data with two different matrixes and under two different ion-mode configurations. Statistical analysis suggests that, even without further improvement, the method described here would successfully scale up to microorganism databases with roughly 1000 microorganisms. The results demonstrate that microorganism identification based on proteome data and modeling can perform as well as methods based on mass spectral fingerprinting.     

Nearest-Neighbours for Time Series

This paper presents an application of lazy learning algorithms in the domain of industrial processes. These processes are described by a set of variables, each corresponding a time series. Each variable plays a different role in the process and some mutual influences can be discovered.A methodology to study the different variables and their roles in the process are described. This methodology allows the structuration of the study of the time series.The prediction methodology is based on a k-nearest neighbour algorithm. A complete study of the different parameters of this kind of algorithm is done, including data preprocessing, neighbour distance, and weighting strategies. An alternative to Euclidean distance called shape distance is presented, this distance is insensitive to scaling and translation. Alternative weighting strategies based on time series autocorrelation and partial autocorrelation are also presented.Experiments using autorregresive models, simulated data and real data obtained from an industrial process (Waste water treatment plants) are presented to show the feasabilty of our approach.     

A layer-wise triangle for analysis of laminated composite plates and shells

The paper presents a new triangle for analysis of laminate plates and shells. The in-plane degrees of freedom are interpolated quadratically whereas a linear layer-wise approximation is chosen for the normal displacement. A substructuring technique is used to eliminate the in-plane degrees of freedom during the assembly process thus reducing substantially the computationed costs. The element performance is evaluated in the static and dynamic analysis of different laminate plate and shell structures.     

Isolation of Platelet-Derived Exosomes from Human Platelet-Rich Plasma: Biochemical and Morphological Characterization

Platelet-Rich Plasma (PRP) is enriched in molecular messengers with restorative effects on altered tissue environments. Upon activation, platelets release a plethora of growth factors and cytokines, either in free form or encapsulated in exosomes, which have been proven to promote tissue repair and regeneration. Translational research on the potential of exosomes as a safe nanosystem for therapeutic cargo delivery requires standardizing exosome isolation methods along with their molecular and morphological characterization. With this aim, we isolated and characterized the exosomes released by human PRP platelets. Western blot analysis revealed that CaCl₂-activated platelets (PLT-Exos-Ca²⁺) released more exosomes than non-activated ones (PLT-Exos). Moreover, PLT-Exos-Ca²⁺ exhibited a molecular signature that meets the most up-to-date biochemical criteria for platelet-derived exosomes and possessed morphological features typical of exosomes as assessed by transmission electron microscopy. Array analysis of 105 analytes including growth factors and cytokines showed that PLT-Exos-Ca²⁺ exhibited lower levels of most analytes compared to PLT-Exos, but relatively higher levels of those consistently validated as components of the protein cargo of platelet exosomes. In summary, the present study provides new insights into the molecular composition of human platelet-derived exosomes and validates a method for isolating highly pure platelet exosomes as a basis for future preclinical studies in regenerative medicine and drug delivery.