Estimating suspended sediment concentrations in turbid coastal waters of the Santa Barbara Channel with SeaWiFS

A technique is presented for estimating suspended sediment concentrations of turbid coastal waters with remotely sensed multi-spectral data. The method improves upon many standard techniques, since it incorporates analyses of multiple wavelength bands (four for Sea-viewing Wide Field of view Sensor (SeaWiFS)) and a nonlinear calibration, which produce highly accurate results (expected errors are approximately ±10%). Further, potential errors produced by erroneous atmospheric calibration in excessively turbid waters and influences of dissolved organic materials, chlorophyll pigments and atmospheric aerosols are limited by a dark pixel subtraction and removal of the violet to blue wavelength bands. Results are presented for the Santa Barbara Channel, California where suspended sediment concentrations ranged from 0–200+ mg?l^?1 (±20?mg?l^?1) immediately after large river runoff events. The largest plumes were observed 10–30?km off the coast and occurred immediately following large El Niño winter floods.     

Absorbable polymer stent technologies for vascular regeneration

Stents are structural implants with widespread clinical use in vascular intervention to re‐open stenotic vessels for the treatment of coronary artery disease and peripheral arterial occlusive disease. Apart from their mechanical function, current drug‐eluting stents (DES) utilize local drug delivery from a drug‐incorporated permanent polymer coating to prevent in‐stent restenosis. This delayed closure of the stented vessel is considered one of the major limitations of conventional bare metal stents (BMS). The long‐term safety of DES, however, is still under debate, with reported cases of delayed healing, late thrombosis and hypersensitivity demanding further evolution in this field. A promising approach to circumvent the limitations of first generation DES is the application of degradable polymer coatings in second generation DES, and fully absorbable polymer stents. From a materials and engineering perspective, this paper provides a mini‐review of current clinically relevant DES technology and recent advancements in the development of stents from degradable polymeric materials as an alternative to permanent BMS and DES. This review, includes work on degradable stents and coatings based on blends of polylactic acid and the microbially‐produced poly(4‐hydroxybutyrate). Copyright © 2009 Society of Chemical Industry     

Enhanced Bioavailability of Eicosapentaenoic Acid from Fish Oil After Encapsulation Within Plant Spore Exines as Microcapsules

Benefits of eicosapentaenoic acid (EPA) can be enhanced by raising their bioavailability through microencapsulation. Pollen can be emptied to form hollow shells, known as exines, and then used to encapsulate material, such as oils in a dry powder form. Six healthy volunteers ingested 4.6 g of fish oil containing 20% EPA in the form of ethyl ester first alone and then as 1:1 microencapsulated powder of exines and fish oil. Serum bioavailability of EPA was measured by area under curve (AUC_0–24). The mean AUC_0–24 of EPA from ethyl ester with exine (M = 19.7, SD = 4.3) was significantly higher than ethyl ester without exines (M = 2, SD = 1.4, p < 0.01).The bioavailability of EPA is enhanced by encapsulation by pollen exines.     

Novel polyamide nanocomposites based on silicate nanotubes of the mineral halloysite

In this study, the silicate nanotubes of the mineral halloysite will be used as reinforcement in polyamide-6 (PA 6). The nanocomposites based on PA-6 and as-received halloysite were prepared by melt extrusion and an adjacent injection moulding process. Mechanical and thermomechanical properties have been investigated by tensile testing and dynamic mechanical analysis. The results show an increased strength and stiffness as well as an enhanced elongation at break at low halloysite content. To evaluate the potential of halloysite as a new candidate in the class of nanofillers, the properties of the halloysite nanocomposites has been compared to those of conventional nanocomposites based on organically modified montmorillonite. From this comparison it can be seen, that both types of nanocomposites show enhanced tensile properties as well as an increased storage modulus, but the increase in tensile strength is more pronounced in the organoclay nanocomposites, whereas the raise of the storage modulus is more prominent in the halloysite nanocomposites.     

Sporopollenin exines: A novel natural taste masking material

Sporopollenin exines extracted from the spores of the plant Lycopodium clavatum were used to encapsulate water, sunflower oil (0.5 g/g) and differing amounts of cod liver oil (cod liver oil per gram of sporopollenin exines: 0.5 g/g, 1.0 g/g, 2.0 g/g, 4.0 g/g). A double-blind taste trial, involving 20 volunteers, was conducted to compare the products. The encapsulated oils were in the form of a fine powder up to an oil loading of 1/1 (w/w). Blind tasting could not distinguish the cod liver oil preparation up to 1/1 (w/w) loading compared to the sporopollenin exines filled with either water or sunflower oil. At a loading of 2/1 and 4/1, the cod liver oil was uniformly identified. Therefore, sporopollenin exines can be loaded highly, at up to 1 g oil to 1 g of the exines, and still remain as a dry powder and retain flavor masking, thus disguising the contents.     

Sorption of pyrene to dissolved humic substances and related model polymers. 2. Solid-phase microextraction (SPME) and fluorescence quenching technique (FHT) as analytical methods

Sorption coefficients for pyrene on dissolved humic substances and on poly(acrylic acid) esters as well-defined model polymers were determined using solid-phase microextraction (SPME) and the fluorescence quenching technique (FQT). The results of both analytical methods were compared and theoretically evaluated, which led to the conclusion that the sorption coefficients measured by SPME and FQT are inevitably different: SPME measures activity-based and FQT concentration-based sorption coefficients. The environmental relevance of the two types of sorption coefficients is discussed. FQT is inappropriate to measure sorption coefficients for pyrene with the synthetic sorbents. Inspection of the vibrational structure of the fluorescence spectra of those solutions indicates a highly hydrophobic microenvironment of pyrene. This can be explained by an intra- or intermolecular agglomeration of hydrophobic moieties forming a favorable host for hydrophobic solutes.     

Conversion of carbon into CF4 for SI-traceable measurements of absolute carbon isotope amount ratios: a feasibility study

The feasibility of performing SI-traceable carbon isotope amount ratio measurements following conversion of carbon into CF4 was studied. A procedure for the direct fluorination of carbon with elemental fluorine was developed, and the conversion step was checked for losses, blank contributions, and the absence of systematic isotope effects. Gas chromatography was used to identify and quantify the gaseous fluorination products and to isolate CF4 from byproducts. After fluorination of graphite carbon, CF4 and perfluoroalkanes with up to six carbon atoms were observed as reaction products. Within an uncertainty of 10%, the graphite carbon was fully recovered in the gaseous carbon fluorides, with the main product being CF4 (80-90%) and C2F6 as the major byproduct. The fluorination and GC procedures were found to introduce an alteration not bigger than 0.03 +/- 0.04/1000 on the isotopic composition of CF4. Carbon blank contributions introduced during the fluorination procedure were below 0.5% relative to a typical sample of 4 mg of carbon. For two of the materials investigated, the carbon isotope ratios measured on a differential mass spectrometer were reproducible within a standard deviation of approximately 0.1/1000 for several individual fluorinations. For these materials, the developed fluorination procedure is a straightforward process, which can be used as a foundation to establish SI-traceable measurements of carbon isotope amount ratios. However, for the third graphite material the formation of byproducts (C2F6-C6F14) was found to induce significant isotopic fractionation.     

Subcellular localization and some biochemical properties of the flavivirus Kunjin nonstructural proteins NS2A and NS4A

1. The mean incidence of deaths from ascites in the UK in 1993 was 1.4% (0.7% in 1991 and 0.9% in 1992) and 0.8% from sudden death syndrome (SDS). In total, the economic loss to the UK Broiler Industry in 1993 as a result of these 2 conditions was 24 Pounds M. 2. Clear geographical differences emerged in the occurrence of ascites, with, not only the lowest incidences being observed in Northern Ireland, but also the peak of the mortality from ascites occurring much later in the rearing cycle than in other regions on the mainland. 3. In all regions the incidence of SDS was lower than that of ascites but the reason for this disparity remains to be established. 4. Some of the variables associated with the road transportation of day-old chicks from the hatchery to the farm appeared to influence the incidence of ascites. These included distance or time travelled, stocking density, internal lorry temperature and the length of time the lorry was heated before transport as well as the time the shed was heated before chick arrival. Temperature was also an important factor during growth (brooding and finishing). 5. Negative pressure-powered ventilation was preferred in most organisations but more ascites was seen with positive pressure ventilation. However, the lowest incidence of ascites occurred with natural ventilation. There was more ascites relative to shed orientation when the wind direction was from the west compared to the east. 6. This survey identifies the extent of the problem of broiler ascites in the UK and also highlights the importance of good management control of day-old chicks, not only following placement, but even before their arrival on the farm.