Search

Aim: To assess if growth restricted (small for gestational age, SGA) extremely preterm infants have excess neonatal mortality and morbidity. Methods: This was a cohort study of all infants born alive at 22-27 weeks' post menstrual age in Norway during 1999-2000. Outcomes were compared between those who were SGA, defined as a birth weight less than the fifth percentile for post menstrual age, and those who had weights at or above the fifth percentile. Results: Of 365 infants with a post menstrual age of <28 weeks, 31 (8%) were SGA. Among infants with a post menstrual age of <28 weeks, only chronic lung disease was associated with SGA status (OR 2.7, 95% CI 1.0 to 7.2). SGA infants with a post menstrual age of 26-27 weeks had excess neonatal mortality (OR 3.8, 95% CI 1.3 to 11), chronic lung disease and a significantly higher mean number of days (age) before tolerating full enteral nutrition. SGA infants with a post menstrual age of 22-25 weeks had an excess risk of necrotising enterocolitis. Conclusion: Extremely preterm SGA infants had excess neonatal mortality and morbidity in terms of necrotising enterocolitis and chronic lung disease. [ABSTRACT FROM AUTHOR]

Colloids, as humic acid, are known to be strong complexing agent for radionuclides. If such colloids are introduced into the bentonite barrier in a repository for spent fuel, the diffusivities for radionuclides can change. The colloid complexed radionuclides diffusivities will be governed by the colloidal diffusivities, and the transport of strongly bentonite sorbed radionuclides might be facilitated into the biosphere.The diffusive properties of Lignosulfonate (LS) colloids dissolved in 0.01 and 0.1 M NaClO4 in bentonite of dry densities 0.6, 0.8, 1.0, 1.2, 1.5, and 1.8 g/cm3 are studied. LS is used as a model substance for humic acid. Independent of ionic strength and of dry density apparent diffusivities in the order of 10−8 cm2/s were obtained. The ratios of effective diffusivity/apparent diffusivity are in accordance with the porosities of the bentonite. The diffusing colloids were not found to be hindered by ionic exclusion or by filtering effects. The results indicate that the LS diffuse through the bentonite as small “uncharged” colloids. It seems that ionic strength ≥0.01 M NaClO4 provides enough ions to shield the charged sites on the colloids, and the colloids can coil into smaller units. [Copyright &y& Elsevier]

Abstract: The environmental behaviour of colloidal clay in aquatic systems is linked to the properties of their aggregates. Earlier investigations of clay colloids were performed with electron microscope techniques which caused de-hydration of the particles. Information on the structure of colloid aggregates is needed for understanding their sedimentation behaviour, as well as colloid contaminant transport properties in natural systems. Scanning transmission X-ray microspectroscopy successfully produced images of montmorillonite colloid aggregates in a pseudo-equilibrium state in 1mM NaCl suspensions equilibrated for more than a year. These clay aggregates were revealed at photon energies below the O absorption edges of clay and water. They were spherical or ellipsoidal with diameters of the order of 100–800nm. The aggregates are porous and gel like with lower densities than the clay mineral. These investigations are important for modelling the occurrence of clay aggregates in aqueous environments. [Copyright &y& Elsevier]

Abstract: Analysis in a single particle mode of gold colloids in water has been performed by inductively coupled plasma-mass spectrometry (ICP-MS). The signal induced by the flash of ions due to the ionization of a colloid in the plasma torch can be measured for the ions 197Au+ by the mass spectrometer without interferences. The intensity of the MS signal is recorded in time scan. The recorded peak distributions were analysed as a function of the colloid size for five monodisperse colloids (80–250nm). This study describes the experimental conditions to analyse gold colloids in a single particle mode. The size detection limit is around 25nm corresponding to 0.15fg colloids and one particle per ml may be detected during a 1min time scan within standard procedure. [Copyright &y& Elsevier]

The percentage of patients requiring cerclage was 37.5%, 58.8%, 43.3%, and 10% of patients with short cervix first seen at 16-18, 18 1/7-20, 20 1/7-22, and 22 1/7-24 weeks, respectively. OC13.01: Multiple gestation and cervical shortening: serial transvaginal cervical length must begin at 16 weeks Despite progesterone use, progressive shortening triggered cerclage in 30/109 (27.5% of short cervix and 2.3% of all multiples). [Extracted from the article]

Abstract: One innovative drilling concept explored in recent years is based on the use of a non-circular well cross section, in particular a well with grooves running along the well axis. The grooves are expected to improve wellbore hydraulics and hole cleaning. In the present study, borehole stability analysis has been carried out for a horizontal rifle well in a high-permeability formation. It has been found that tensile failure is likely to develop at several locations around the non-circular cross section, a failure mode that is not normally found in conventional (circular) wells. The numerical results obtained with a finite-element code have been qualitatively confirmed in a dedicated laboratory experiment performed on a block of concrete with a section of non-circular well. In the experiment, the unusual failure mode was clearly observed. Traditional breakouts were also observed in the same test, but had smaller size. Numerical simulations have been carried out for different drilling conditions, both onshore and offshore, and depths from 1000m to 2000m, normal or abnormal pore pressure. The borehole was always found to fail in tension unless a considerable overbalance was applied by the drilling fluid. Similar results were obtained with formations that had hydrostatic pore pressure, elevated pore pressure (overpressure) or reduced pore pressure (underpressure, depleted reservoirs). The results are of importance for practical application of non-circular wells. [Copyright &y& Elsevier]

Abstract: The interaction between silver nanoparticles (Ag NPs) of different surface charge and surfactants relevant to the laundry cycle has been investigated to understand changes in speciation, both in and during transport from the washing machine. Ag NPs were synthesized to exhibit either a positive or a negative surface charge in solution conditions relevant for the laundry cycle (pH 10 and pH 7). These particles were characterized in terms of size and surface charge and compared to commercially laser ablated Ag NPs. The surfactants included anionic sodium dodecylbenzenesulfonate (LAS), cationic dodecyltrimethylammoniumchloride (DTAC) and nonionic Berol 266 (Berol). Surfactant–Ag NP interactions were studied by means of dynamic light scattering, Raman spectroscopy, zeta potential, and Quartz Crystal Microbalance. Mixed bilayers of CTAB and LAS were formed through a co-operative adsorption process on positively charged Ag NPs with pre-adsorbed CTAB, resulting in charge reversal from positive to negative zeta potentials. Adsorption of DTAC on negatively charged synthesized Ag NPs and negatively charged commercial Ag NPs resulted in bilayer formation and charge reversal. Weak interactions were observed for nonionic Berol with all Ag NPs via hydrophobic interactions, which resulted in decreased zeta potentials for Berol concentrations above its critical micelle concentration. Differences in particle size were essentially not affected by surfactant adsorption, as the surfactant layer thicknesses did not exceed more than a few nanometers. The surfactant interaction with the Ag NP surface was shown to be reversible, an observation of particular importance for hazard and environmental risk assessments. [Copyright &y& Elsevier]

Abstract: Uranium single particle analysis has been performed by inductively coupled plasma-mass spectrometry (ICP-MS) and the performances are compared with that provided by scanning electron microsopy and single particle counting. The transient signal induced by the flash of ions due to the ionisation of an uranium colloidal particle in the plasma torch can be detected and measured for selected uranium ion masses (238U+, 235U+ or 254[238U16O]+) by the mass spectrometer. The signals recorded via time scanning are analysed as a function of particle size or fraction of the studied element or isotope in the colloid phase. The frequency of the flashes is directly proportional to the concentration of particles in the colloidal suspension. The feasibility tests were performed on uranium dioxide particles. The study also describes the experimental conditions and the choice of mass to detect uranium colloids in a single particle analysis mode. [Copyright &y& Elsevier]

When X and Y are multivariate, the two-block partial least squares (PLS) method is often used. In this paper, we outline an extension addressing a special case of the three-block (X/Y/Z) problem, where Z sits "under" Y. We have called this approach three-block bi-focal PLS (3B1F-PLS). It views the X/Y relationship as the dominant problem, and seeks to use the additional information in Z in order to improve the interpretation of the Y-part of the X/Y association. Two data sets are used to illustrate 3BIF-PLS. Example 1 relates to single point mutants of haloalkane dehalogenase from Sphingomonas paucimobilis UT26 and their ability to transform halogenated hydrocarbons, some of which are found as organic pollutants in soil. Example II deals with soil remediation capability of bacteria. Whole bacterial communities are monitored over lime using "DNA-fingerprinting" technology to see how pollution affects population composition. Since the data sets are large, hierarchical multivariate modelling is invoked to compress data prior to 3BIF-PLS analysis. It is concluded that the 3BIF-PLS approach works well. The paper contains a discussion of pros and cons of the method, and hints at further developmental opportunities. [ABSTRACT FROM AUTHOR]