Reynolds number effects within the development region of a turbulent round free jet

In this work, flying and stationary hot-wire measurements were made to investigate the effect of the Reynolds number on the near- and intermediate-fields region (0 ? x/D ? 25) of a round free jet. Measurements were carried out over a range of Reynolds numbers, based on the jet exit mean velocity and the nozzle diameter, that span the mixing transition. The specific Reynolds numbers tested were 6000, 10,000 and 30,000. The objective of this study was to determine what differences there were in mean velocity profiles, turbulence intensity profiles, and velocity spectra. Results revealed a close coupling between the mean velocity distribution and the turbulence intensities and the Reynolds shear stress. From those data obtained, it was concluded that the inertial sub-range frequency span increases with distance downstream from the jet inlet and the mixing transition seems to occur at the appearance of the inertial sub-range rather than at the transition from the inertial to dissipation range.     

Sensitive and meaningful measures of bacterial metabolic activity using NADH fluorescence

Successful biological wastewater treatment depends on bacterial metabolic activity. Commercial fluorimeters are designed to monitor this activity using the native fluorescence of Nicotinamide Adenine Dinucleotide [NADH]. However, fluorescence measurements in wastewater treatment plants remain scarce due to difficulties with interpreting fluorescence data. This paper shows that fluorescence probe measurements taken from wastewater do not represent bacterial cell metabolic activity because intracellular NADH is likely swamped by the stable extracellular NADH fraction. Thus, a simple filtration/extraction/centrifugation method was developed to collect the bacterial cells, extract the intracellular NADH using heat treatment in Tris buffer and collect the purified intracellular NADH fraction. NADH standards were used to quantify NADH from the unknown wastewater samples where limits of detection were between 1 nmol mL(-1) and 0.35 micromol mL(-1). Fluorescence of [NADH] greater than 0.35 micromol mL(-1) was self-quenched. At high pH's NADH was stable outside the cell. NADH was stable at neutral and basic pH ranges of pH 7 to 11, but declined proportionally below a pH of 7. Since commercially available fluorescence probes used for measuring NADH are more likely detecting extracellular NADH, separating bacterial cells from water samples followed by NADH extraction was essential to distinguish intracellular and extracellular [NADH]. Here we have proposed three simple steps to meaningful measures of bacterial metabolic activity based on the autofluorescence of NADH. The three simple steps to getting it right are Future development of an on-line monitoring system based on these three steps is achievable with a little ingenuity.     

Additive Manufacturable Materials for Electrochemical Biosensor Electrodes

With the impending Industrial Revolution 4.0, the information produced by sensors will be central in many applications. This includes the healthcare sector, where affordable healthcare and precision medicine are highly sought after. Electrochemical sensors have the potential to produce affordable, high sensitivity and specificity, intuitive, and rapid point-of-care diagnostics. Underpinning these achievements is the choice of material and the fabrication thereof. In this review, the different types of materials used in electrochemical biosensors are reported, with a focus on synthetic conductive materials. The review demonstrates that there is an abundance of materials to select from, and compositing different types of materials further widens their applicability in biosensors. In addition, the fabrication of such materials using the state-of-the-art of fabrication technology, additive manufacturing (AM), is also detailed. The need for compositing is evident in AM, as the feedstock for certain AM technologies is inherently nonconductive. Both material choice and fabrication technologies limitations are also discussed to highlight opportunities for growth. The review highlights how recent technological advancements have the potential to drive the healthcare industry toward achieving its primary goals.     

A novel receptor-mediated nuclear protein import pathway

Targeting of most nuclear proteins to the cell nucleus is initiated by interaction between the classical nuclear localization signals (NLSs) contained within them and the importin NLS receptor complex. We have recently delineated a novel 38 amino acid transport signal in the hnRNP A1 protein, termed M9, which confers bidirectional transport across the nuclear envelope. We show here that M9-mediated nuclear import occurs by a novel pathway that is independent of the well-characterized, importin-mediated classical NLS pathway. Additionally, we have identified a specific M9-interacting protein, termed transportin, which binds to wild-type M9 but not to transport-defective M9 mutants. Transportin is a 90 kDa protein, distantly related to importin beta, and we show that it mediates the nuclear import of M9-containing proteins. These findings demonstrate that there are at least two receptor-mediated nuclear protein import pathways. Furthermore, as hnRNP A1 likely participates in mRNA export, it raises the possibility that transportin is a mediator of this process as well.     

Automated algorithm for the nondestructive detection of subsurface cavities by the IR-CAT method

An algorithm is presented to automate the detection of irregular-shaped subsurface cavities within irregular shaped bodies by the IR-CAT method. The algorithm is based on the solution of an inverse geometric steady state heat conduction problem. Cauchy boundary conditions are prescribed at the exposed surface. An inverse heat conduction problem is formulated by specifying the thermal boundary condition along the inner cavities whose unknown geometries are to be determined. An initial guess is made for the location of the inner cavities. The domain boundaries are discretized, and an Anchored Grid Pattern (AGP) is established. The nodes of the inner cavities are constrained to move along the AGP at each iterative step. The location of inner cavities is determined by using the Newton Raphson method with a Broyden update to drive the error between the imposed boundary conditions and computed boundary conditions to zero. During the iterative procedure, the movement of the inner cavity walls is restricted to physically realistic intermediate solutions. A dynamic relocation of the AGP is introduced in the Traveling Hole Method to adaptively refine the detection of inner cavities. The proposed algorithm is general and can be used to detect multiple cavities. Results are presented for the detection of single and multiple irregular shaped cavities. Convergence under grid refinement is demonstrated.     

Guest editor's foreword.

Editorial introduces the special issue as the inaugural project of the American Psychological Association's Division 22's Special Interest Section on Deafness (SISD). The articles compiled herein reflect the diversity of research psychologists' interests in the deafness field as well as the current focus that many have on mental health issues. These articles are briefly overviewed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Food Cent$--implementing and evaluating a nutrition education project focusing on value for money

The photophysics and polarization of the phosphorescence and delayed fluorescence of erythrosin in conditions compatible with the current biological applications of the dye (aqueous buffers at pH 7.4 at ambient temperatures) and in ethanol have been studied as a function of dye concentration (10(-7)-10(-5) M) and temperature (245-333 K). The emission decay is strictly single exponential and the detailed kinetic analysis of all the rate processes connected with the emitting T1 state showed that (1) the lowering of the emission lifetime at the higher temperatures is due to a very efficient self-quenching process, (2) the back intersystem crossing rate T1-->S1 is temperature dependent (delta ETS approximately 7 kcal mol-1) but the T1-->S0 is not (Ea < 0.1 kcal mol-1) and (3) both intersystem crossing processes are very sensitive to solvent polarity, which accounts for the solvent dependence of the phosphorescence yield and lifetime. The high value of the phosphorescence anisotropy (r0 = 0.25 +/- 0.006) is independent of the excitation and emission wavelengths, and its evolution in time accurately reflects the rotational restrictions in solid solutions. The relevance of these findings to studies with protein-dye conjugates is also outlined to facilitate the design and interpretation of phosphorescence depolarization experiments that probe the microsecond-ms dynamics of biomolecules and supramolecular systems.     

A study of the effect of molecular weight on the tensile strength of ultra-high modulus polyethylenes

In this paper the influence of molecular weight and molecular weight distribution on the tensile strength (tenacity) of melt spun and drawn linear polyethylene are investigated with the aim of outlining the requirements for a high strength fibre. The tenacity was investigated over the molecular weight average ¯M _w range 60×10³ to 330×10³ with polydispersities ¯M _w/¯M _n ranging from 1.1 to 13.3. It was found that both molecular weight and its distribution affected tensile strength. The drawing conditions were also found to be important, a high draw temperature and a high draw ratio being needed for a high strength, high modulus fibre. By using a polymer of high ¯M _w and low polydispersity, and drawing at the optimum conditions, strengths of 1.65 GPa and moduli of 85 GPa have been achieved for test temperatures of –55° C.