On the Averaging of Equations of Change for Mass,Species Mass,Momentum and Energy – One-Dimensional Pipe Flows

The single-phase and multiphase Eulerian equations of change are derived by applying a suitable averaging procedure to the local instantaneous equations of change. In the present work, the local instantaneous equations of change for mass, species mass, momentum and energy are gross-scale averaged over the cross-sectional area. In particular, the internal energy equation is achieved by subtracting the kinetic energy equation from the total energy balance. Thus, two paths are to our disposal for deriving the cross-sectional averaged internal energy balance: (i) the averaged kinetic energy equation is subtracted from the averaged total energy equation, or (ii) the local instantaneous kinetic energy equation is subtracted from the local instantaneous energy equation and the resulting equation is averaged. The resulting Euler equations of change for internal energy are not identical for these two approaches. Approach (ii) is recommended because of its simplicity.     

Mutual coupling between identical planar inverted-F antennas

Mutual coupling between two identical planar inverted-F antennas (PIFA) located on an infinite ground plane is studied numerically. Several arrangements of side-by-side, collinear, parallel-in-echelon, and orthogonal PIFA antennas with element spacing varying from $0.06\lambda$ to $1.20\lambda$ are investigated at the design frequency of 1.9 GHz, and in the $-6\mathrm{dB}$ bandwidth between 1.8 and 2.0 GHz. It is found that choosing configurations that maximizes the separation between the open-end of the PIFAs reduces the mutual coupling.     

Crystal structures of high affinity human T-cell receptors bound to peptide major histocompatibility complex reveal native diagonal binding geometry

Naturally selected T-cell receptors (TCRs) are characterised by low binding affinities, typically in the range 1-100 microM. Crystal structures of syngeneic TCRs bound to peptide major histocompatibility complex (pMHC) antigens exhibit a conserved mode of binding characterised by a distinct diagonal binding geometry, with poor shape complementarity (SC) between receptor and ligand. Here, we report the structures of three in vitro affinity enhanced TCRs that recognise the pMHC tumour epitope NY-ESO(157-165) (SLLMWITQC). These crystal structures reveal that the docking mode for the high affinity TCRs is identical to that reported for the parental wild-type TCR, with only subtle changes in the mutated complementarity determining regions (CDRs) that form contacts with pMHC; both CDR2 and CDR3 mutations act synergistically to improve the overall affinity. Comparison of free and bound TCR structures for both wild-type and a CDR3 mutant reveal an induced fit mechanism arising from restructuring of CDR3 loops which allows better peptide binding. Overall, an increased interface area, improved SC and additional H-bonding interactions are observed, accounting for the increase in affinity. Most notably, there is a marked increase in the SC for the central methionine and tryptophan peptide motif over the native TCR.     

Hierarchical nanostructures of PbTiO3 through mesocrystal formation

Novel hierarchical self-assembled structures; bur-like PbTiO3 nanostructures were made by self-assembly of PbTiO3 nanocrystals under hydrothermal conditions using sodium dodecylbenzene sulfonate surfactant. The bur-like nanostructures exhibit a unique geometrical shape with cores of agglomerated nanocrystals and outershells of nanorods. The nanorods were between 30 nm and 100 nm in diameter and from several hundred nm up to 2 microm in length. We demonstrate that these nanostructures are formed in a two step process where agglomeration of PbTiO3 nanoparticles into microspheres occurs in a first step, followed by assembly of cube-shaped nanoparticle building blocks into PbTiO3 mesocrystals in a second step. The mesocrystals continuously grow into nanorods from the surface of the microspheres acting as a substrate.     

Heaps and heapsort on secondary storage

A heap structure designed for secondary storage is suggested that tries to make the best use of the available buffer space in primary memory. The heap is a complete multi-way tree, with multi-page blocks of records as nodes, satisfying a generalized heap property. A special feature of the tree is that the nodes may be partially filled, as in B-trees. The structure is complemented with priority-queue operations insert and delete-max. When handling a sequence of S operations, the number of page transfers performed is shown to be O(∑_{i = 1}^S(1/P) log_(M/P)(N_i/P)), where P denotes the number of records fitting into a page, M the capacity of the buffer space in records, and N_i, the number of records in the heap prior to the ith operation (assuming P 1 and S> M c · P, where c is a small positive constant). The number of comparisons required when handling the sequence is O(∑_{i = 1}^S log₂ N_i). Using the suggested data structure we obtain an optimal external heapsort that performs O((N/P) log_(M/P)(N/P)) page transfers and O(N log₂ N) comparisons in the worst case when sorting N records.     

Aerodynamic investigations for the tender design concepts of the Øresund cable-stayed bridge

For the Øresund link project two alternative tender designs were proposed, one single-level box girder solution and a double-level truss girder solution. Aerodynamic investigations, comprising wind tunnel section model tests as well as full-scale predictions, were carried out for the cable-stayed part of the two design alternatives. The section model tests covered static and dynamic tests for various configurations of bridge deck equipment, aiming at the detection of possible instabilities or vortex shedding effects and recording of the buffeting response. Cross-sectional admittance functions and aerodynamic derivatives have been estimated, and employed for full-scale predictions of dynamic displacements at a chosen value of the characteristic mean wind speed.     

Endocytosis and vacuolar morphology in Saccharomyces cerevisiae are altered in response to ethanol stress or heat shock

The vital lipophilic dye N‐(3‐triethylammoniumpropyl)‐4‐[6‐(4‐(diethylamino)phenyl]hexatrienyl) pyridinium dibromide (FM 4‐64) was used to study the effect of ethanol stress and heat shock on endocytosis in the yeast Saccharomyces cerevisiae. Yeast cells stained with FM 4‐64 were placed in a culture chamber and the internalization of the dye was monitored by fluorescence microscopy during perfusion of the cells with fresh growth medium. In the absence of ethanol in the perfusion medium, the internalization of FM 4‐64 from the plasma membrane to the vacuolar membrane by yeast cells harvested from the exponential phase of growth was completed in 30 min. The presence of 6% (v/v) ethanol in the perfusion medium had no obvious effect on the internalization of FM 4‐64 from the plasma membrane, but did lead to an accumulation of the dye in endocytic intermediates. Consequently, vacuolar membrane staining was delayed. Cells stained with FM 4‐64 and subjected to heat shock displayed a similar effect, with endocytic intermediates becoming more prominent with the severity of the heat shock. For both ethanol stress and heat shock, vacuolar morphology altered from segregated structures to a single, large organelle. The findings of this study reinforce previous observations that ethanol stress and heat shock induce similar responses in yeast. Copyright © 1999 John Wiley & Sons, Ltd.     

Xylanases in Wheat Separation

Hemicellulases used in the wheat separation process have resulted in better separation, purer fractions, increased plant capacity, reduced processing time etc. In order to further improve enzyme-treatment in the wheat separation process, monocomponent xylanases were evaluated. A laboratory viscosity model has been set up to evaluate the xylanases. The model showed good correlation (for a commercial hemicellulase preparation used for wheat separation) between viscosity of the wheat flour slurry and the sludge/supernatant ratio after centrifugation of the slurry. A xylanase (Novozyme 867) with excellent performance in the wheat separation process has been found. The xylanase has high activity towards soluble arabinoxylan and gives a rapid viscosity reduction of wheat flour slurries. The enzyme also has a moderate activity towards insoluble arabinoxylan, but due to the low molecular weight of the solubilized material this was not was found to contribute negatively to the enzymes' performance. The pH and temperature conditions in the wheat separation process were well within the active range of the enzyme. A pilot plant experiment showed improved yield of gluten and A-starch, with no apparent negative effect on the gluten quality.     

An optimized FAIRE procedure for low cell numbers in yeast

We report an optimized low‐input FAIRE‐seq (Formaldehyde‐Assisted Isolation of Regulatory Elements‐sequencing) procedure to assay chromatin accessibility from limited amounts of yeast cells. We demonstrate that the method performs well on as little as 4 mg of cells scraped directly from a few colonies. Sensitivity, specificity and reproducibility of the scaled‐down method are comparable with those of regular, higher input amounts, and allow the use of 100‐fold fewer cells than existing procedures. The method enables epigenetic analysis of chromatin structure without the need for cell multiplication of exponentially growing cells in liquid culture, thus opening the possibility of studying colony cell subpopulations, or those that can be isolated directly from environmental samples.