Some observations relating to the stability of the BODIPY fluorophore under acidic and basic conditions

4,4-Difluoro-4-bora-1,3,5,7-tetramethyl-2,6-diethyl-8-methyl-3a,4a-diaza-s-indacene (BODIPY) fluorophore was transformed into its corresponding 4,4-dimethyl, 4,4-dimethoxy and 4,4-diphenyl analogues. The stabilities of these BODIPY fluorophores in acidic (di- and trichloroacetic acid) and basic conditions (aqueous ammonium hydroxide) were investigated using ¹¹B NMR spectroscopy.     

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.     

The lateral stiffness and damping of a stretched rubber beam

A theory is presented for the effect of axial strain on the stiffness and damping of a rubber strip clamped at its ends and deformed laterally. Experiments on such a system were carried out, varying the tensile strain and the sample dimensions. Both free and forced oscillations were used, the former giving more accurate results for the damping. The results were compared with the theoretical predictions with very good agreement. The work suggests that it may be possible to vary the damping of an engineering component by design of the shape and mode of application of the forces, rather than by variation of the rubber compound out of which it is made. This presents possible advantages with regard to overall performance of the component, for example, the temperature sensitivity. It also suggests a mechanism for possible artefacts in characterisation tests for elastic and loss moduli of the material.     

Improving the effectiveness of computer-delivered personalized drinking feedback interventions for college students.

This study evaluated methods of enhancing college students' retention of information provided to them in a computer-delivered personalized drinking feedback intervention and whether enhanced retention reduced alcohol consumption during the two-week period following the intervention. Participants were 98 college students who reported at least one heavy drinking episode in the past two weeks. After participating in an online, personalized drinking feedback intervention, students were randomly assigned to one of three experimental conditions: 1) typical, in which they were simply sent home, 2) reading, in which they were asked to spend the next 20 minutes re-reading the feedback, and 3) recall, in which they were asked to spend the next 20 minutes writing down as much of the information from the feedback as they could remember. Two weeks following the intervention, participants completed a recall test and provided information on their alcohol use during the previous two weeks. Results indicated that participants in the reading and recall conditions retained more of the feedback information than did participants in the typical condition. In addition, participants in the reading and recall conditions reported reduced alcohol consumption in the two-week period following the intervention, compared to those in the typical condition. Information retention partially mediated the effects of the reading and recall conditions on drinking outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissolved silver in European estuarine and coastal waters

Silver is one of the most toxic elements for the marine microbial and invertebrate community. However, little is known about the distribution and behaviour of dissolved silver in marine systems. This paper reports data on dissolved and sediment-associated silver in European estuaries and coastal waters which have been impacted to different extents by past and present anthropogenic inputs. This is the first extended dataset for dissolved silver in European marine waters. Lowest dissolved silver concentrations were observed in the Gullmar Fjord, Sweden (8.9 ± 2.9 pM; x ± 1σ), the Tamar Estuary, UK (9.7 ± 6.2 pM), the Fal Estuary, UK (20.6 ± 8.3 pM), and the Adriatic Sea (21.2 ± 6.8 pM). Enhanced silver concentrations were observed in Atlantic coastal waters receiving untreated sewage effluent from the city of A Cor?na, Spain (243 ± 195 pM), and in the mine-impacted Restronguet Creek, UK (91 ± 71 pM). Anthropogenic wastewater inputs were a source of dissolved silver in the regions studied, with the exception of the Gullmar Fjord. Remobilisation of dissolved silver from historically contaminated sediments, resulting from acid mine drainage or sewage inputs, provided an additional source of dissolved silver to the estuaries. The ranges in the log particle-water partition coefficient (K_d) values of 5-6 were similar for the Tamar and Mero estuaries and agreed with reported values for other estuaries. These high K_d values indicate the particle reactive nature of silver with oxic sediments. In contrast, low K_d values (1.4-2.7) were observed in the Fal system, which may have been due to enhanced benthic inputs of dissolved silver coupled to limited scavenging of silver on to sediments rich in Fe oxide.     

Test-Driven Development for Spreadsheet Risk Management

Spreadsheet technology is central to the functioning of the financial sector, but professionally created spreadsheets have a high level of error, which highlights the need for innovative supporting processes and tools. The current global financial crisis will likely accelerate this need because anticipated regulation will require novel, innovative risk management methods and technologies that cover development, risk assessment, review, and other spreadsheet activities. These methods will need to be easy to understand and use and will have to serve multiple stakeholders' needs. Test-driven spreadsheet development (TDSD) is one such method. TDSD provides an ideal fit with existing market-leading spreadsheet management processes and can assist managers and auditors in the assessment and control of spreadsheet risk.     

Kinetic analysis of NaF vaporization in SiF4-Ar mixture

Slags used in steelmaking and continuous casting that contain SiO₂, Na₂O, and CaF₂ tend to be unstable and gaseous. Species, such as NaF and SiF₄, evolve simultaneously from these slags at steelmaking temperatures. In addition, the reaction between NaF and SiF₄ can occur to produce Na₂SiF₆ (sodium hexafluorosilicate). In a previous study on the vaporization of NaF into an inert gas stream, the diffusivity of NaF in argon, nitrogen, and helium was measured. In this study, the rate of NaF vaporization in a SiF₄ atmosphere was measured. Ternary diffusion coefficients were then evaluated from the binary diffusion coefficients obtained in a previous study, and a kinetic analysis was carried out. The rate calculations were found to be in accord with the measured results, indicating that the experiments were carried out in a regime where diffusion of NaF from the surface of the sample was rate controlling.     

Control of a polyphase induction generator/induction motor powerconversion system completely isolated from the utility

Two squirrel cage induction machines interconnected via a 20 kHz parallel resonant high frequency (HF) AC link and associated switching pulse density modulated (PDM) power converters are investigated, one operating as a generator and the other as a motor. No capacitors are used for the excitation of the generator or motor. Instead, the real power of the generator is controlled so as to maintain the proper link voltage and match the power between the input and output, Current regulated PDM converters operating via field oriented controllers are used to control both machines. A zero voltage switching technique is utilized with the associated PDM converters. Low harmonic distortion waveforms have been obtained both at the input and output due to the high 40 kHz switching frequency. Link voltage build-up and excitation of the generator by an initial charging circuit, power matching between input and output, and peak link voltage regulation techniques are investigated. Both computer simulations and experimental results demonstrate the feasibility of the proposed system