Hydrolysis of intralipid by pancreatic lipase and phospholipase A2-gel filtration studies

Intralipid was incubated with pancreatic lipase (EC 3.1.1.3) and/or phospholipase A₂ (EC 3.1.1.4) at two bile salts/phosphatidylcholine molar ratios and at two different triglyceride hydrolysis rates using various amounts of lipase. Incubations were studied by gel filtration. Results show: (i) During lipase action, three phases of lipids coexist: an emulsified phase, a micellar phase and an intermediate heavy phase sized between the two others. The equilibrium between each phase is dependent upon the bile salts concentration. (ii) Under these conditions, pancreatic lipase was at 60% bound to the emulsified phase, whereas pancreatic phospholipase A₂ was bound at 94% to the micellar phase.     

Transition from subcritical to supercritical bifurcation in penetrative convection in a vertical cylinder

The stability of a vertical cylindrical column of water with the horizontal bottom boundary maintained at 0°C and the temperature of the top boundary varying between 4 and 8°C is considered. A weakly non-linear analysis shows that the bifurcation is either supercritical or subcritical depending upon the values of two parameters: the aspect ratio of the cylinder (height/radius) which is varied between 2 and 4, and the penetration parameter μ defined as the ratio of the whole height over the height of the 4°C isotherm. For a given value of the aspect ratio, the bifurcation is supercritical when the whole height is unstable (μ = 1) and becomes subcritical above a particular value of μ when penetration occurs (μ > 1).     

Detection of β‐Amyloid by Sialic Acid Coated Bovine Serum Albumin Magnetic Nanoparticles in a Mouse Model of Alzheimer's Disease

The accumulation and formation of β‐amyloid (Aβ) plaques in the brain are distinctive pathological hallmarks of Alzheimer's disease (AD). Designing nanoparticle (NP) contrast agents capable of binding with Aβ highly selectively can potentially facilitate early detection of AD. However, a significant obstacle is the blood brain barrier (BBB), which can preclude the entrance of NPs into the brain for Aβ binding. In this work, bovine serum albumin (BSA) coated NPs are decorated with sialic acid (NP‐BSA_x‐Sia) to overcome the challenges in Aβ imaging in vivo. The NP‐BSA_x‐Sia is biocompatible with high magnetic relaxivities, suggesting that they are suitable contrast agents for magnetic resonance imaging (MRI). The NP‐BSA_x‐Sia binds with Aβ in a sialic acid dependent manner with high selectivities toward Aβ deposited on brains and cross the BBB in an in vitro model. The abilities of these NPs to detect Aβ in vivo in human AD transgenic mice by MRI are evaluated without the need to coinject mannitol to increase BBB permeability. T₂*‐weighted MRI shows that Aβ plaques in mouse brains can be detected as aided by NP‐BSA_x‐Sia, which is confirmed by histological analysis. Thus, NP‐BSA_x‐Sia is a promising new tool for noninvasive in vivo detection of Aβ plaques.     

Generating and exploiting customer insights from social media data

Previous research has emphasized the virtues of customer insights as a key source of competitive advantage. The rise of customers’ social media use allows firms to collect customer data in an ever-increasing volume and variety. However, to date, little is known about the capabilities required of firms to turn social media data into valuable customer insights and exploit these insights to create added value for customers. Based on the dynamic capabilities perspective, in particular the concept of absorptive capacity (ACAP), the authors conducted multiple case studies of seven mid-sized and large B2C firms in Switzerland and Germany. The results provide an in-depth analysis of the underlying processes of ACAP as well as contingent factors – that is, physical, human and organizational resources that underpin the firms’ ACAP.     

Emergent vegetation in Netley-Libau Marsh: Temporal changes (1990–2013) in cover in relation to Lake Winnipeg level and Red River flow

A time-series (1990–2013) of classified vegetation cover maps was produced for Netley-Libau Marsh, a 26,000 ha coastal wetland on Lake Winnipeg, to assess its current status and verify earlier trends of emergent vegetation loss. Open water area in the marsh was measured from late-summer Landsat images for 20 years; three classes of vegetation types (emergents, wet meadows, upland) could also be identified for 12 images covering the same period. Temporal changes in area and distribution of marsh vegetation were related to adjoining Lake Winnipeg water-level and Red River discharge, as well as marsh connectivity and bathymetry. From 1990 to 2002, an increase in open-water areas and decrease in emergent vegetation coincided with rising levels and flows. The year 2003 marked major wetland regeneration and a decrease of open-water area under extremely low water-levels and flows. From 2005 to 2013, open-water area remained consistent, under high but variable levels and flows. A strong negative correlation was found between area of emergent vegetation and mean Red River discharge in the previous June-July. Superimposition of the limit of new emergent vegetation observed in 2003 with depth contours surveyed in 2010 revealed the dynamic nature of marsh bathymetry. Periods of extremely low water as short as one year (2003) induced a marked expansion in emergent vegetation cover that persisted over the next ten years despite higher water-levels. Rather than being gradual, changes in the spatial extent of Netley-Libau Marsh vegetation appeared to proceed by fits and starts, wherein periods of relative stasis were disrupted by major changes in abundance.     

Gehalte des PCB-Ersatzproduktes Ugilec (Tetrachlorbenzyltoluole) in Fischen aus Gebieten mit intensivem Bergbau

Zusammenfassung Tetrachlorbenzyltoluole, die den Hauptanteil in den PCB-Ersatzprodukten Ugilec 141 und Ugilec T bilden, haben in letzter Zeit eine weite Verbreitung als Hydraulikflüssigkeit im Untertagebergbau gefunden. Der Einsatz erfolgt zwar in geschlossenen Systemen, offenbar kommt es aber trotzdem zu nicht unerheblichen Verlusten, wobei die Hydraulikflüssigkeit freigesetzt wird und z. B. über Grubenabwässer in die Umwelt gelangt. So konnten in Flußfischen aus Gebieten mit intensivem Bergbau Te trachlorbenzyltoluole bis zu einer Konzentration von 25 mg/kg eßbarem Anteil bestimmt werden. Die Extraktion der Tetrachlorbenzyltoluole erfolgt aus dem gefriergetrockneten Probenmaterial mit Petrolether. Nach gelchromatographischer Abtrennung des Fettes an Bio-Beads S-X3 schließt sich eine Adsorptionschromatographie an Kieselgel nach Specht u. Tillkes an. Für die analytische Bestimmung wird die kombinierte Capillargaschromatographie/Massenspektrometrie eingesetzt. Die große Spezifität der massenselektiven Detektion, verbunden mit der hohen Trennkraft der Capillargaschromatographie, erlaubt es, Ugilec bis zu einer Konzentration von 0,02 mg/kg, auch in Gegenwart eines hohen PCB-Überschusses, in Fischen sicher nachzuweisen.

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Levels of the PCB-substitute Ugilec (tetrachlorobenzyltoluenes) in fish from areas with extensive mining

Summary Tetrachlorobenzy1toluenes, which represent the major constituent of the PCB substitutes Ugilec 141 and Ugilec T, have been widely used in the last few years as hydraulic fluids in underground mining. Their use has been termed a closed application, but there are obviously considerable losses. Tetrachlorobenzyltoluenes released underground can enter the environment via pit water, mine outputs or ventilation systems and as a consequence they can contaminate the food-chain, especially in fish. In fish from areas where there is extensive mining concentrations of tetrachlorobenzy1toluenes in edible portions ranged up to 25 mg/kg. The compounds were extracted from the freeze-dried material with petroleum ether. Gel chromatography on Bio-Beads S-X3 was chosen for the removal of fat followed by adsorption chromatography on silica gel according to the method of Specht and Tillkes. A combination of gas chromatography/mass spectrometry employing an ion trap detector was used for the separation and detection of the compounds. The great selectivity of mass selective detection combined with the high resolving power of capillary gas chromatography made it possible to determine and confirm the presence of Ugilec in fish down to a level of 0.02 mg/kg, even if there was a large PCB surplus.

     

Design,Synthesis and Biological Evaluation of Highly Potent Simplified Archazolids

The archazolids are potent antiproliferative compounds that have recently emerged as a novel class of promising anticancer agents. Their complex macrolide structures and scarce natural supply make the development of more readily available analogues highly important. Herein, we report the design, synthesis and biological evaluation of four simplified and partially saturated archazolid derivatives. We also reveal important structure-activity relationship data as well as insights into the pharmacophore of these complex polyketides.     

Chemical Identification, Emission Pattern and Function of Male-Specific Pheromones Released by a Rarely Swarming Locust, Schistocerca americana

Pheromones serve key functions in the biology of swarming locusts. However, research has focused largely on the mass-swarming desert locust, Schistocerca gregaria. We extended these investigations to the pheromonal profile of the rarely swarming American bird grasshopper, S. americana (Drury). The headspace of mature gregarious S. americana males contained three characteristic electroantennogram-active components: (Z)-3-nonen-1-ol, (Z)-2-octen-1-ol, and nonanal. These substances were accompanied by aromatics such as phenol that are also released by females and immatures. Male-specific pheromone components were released independently from epidermal gland cells, with the highest emission rate being for (Z)-3-nonen-1-ol from the abdomen and legs. The emission of the major compound, (Z)-3-nonen-1-ol, is stress-sensitive, and coincides with sexual maturity and crowding. The emission pattern strongly supports a role of (Z)-3-nonen-1-ol in the reproductive biology of S. americana. The pheromone is involved in courtship-inhibition and is used as mate assessment pheromone in cryptic female choice. In double mating experiments, females choose sperm of males with high (Z)-3-nonen-1-ol emission. Furthermore the pheromone accelerated maturation of immature adults and supports synchronization of sexual development.