On the Fermi functionsI −(n+1/2)

We point out that an integral representation is possible for the Fermi functionsI _?3/2,I _?5/2,I _?7/2,I _?9/2, andI _?11/2 that arise in the extended Thomas-Fermi theory of hot, non-relativistic fermion systems. These functions can thus be computed by straightforward numerical integration, thereby avoiding problems previously encountered.     

Intramolecular cross-linking experiments on cytochrome c and ribonuclease A using an isotope multiplet method.

Mass spectral analysis of tryptic digests of cross-linked proteins offers considerable promise as a simple technique to probe protein structure and study protein-protein interactions. We describe the use of a 1:1 mixture of isotopically labeled and unlabeled cross-linkers, disuccinimidyladipate (DSA) and dimethyladipimidate (DMA), to enhance visualization of cross-linked peptides in a tryptic digest. Optimized intramolecular reactions of cytochrome c and ribonuclease A (RNase A) with DSA yielded an average of two cross-links per protein molecule. After digestion of the cross-linked cytochrome c with trypsin and analysis by liquid chromatography/mass spectrometry (LC/MS) and matrix-assisted laser desorption/ionization (MALDI), eight modified peptides, five cross-linked and two end-capped, were detected by virtue of their doublet character. An eighth modified peptide's identity remained ambiguous because of its inability to fragment. The lysine-lysine distance constraints obtained are discussed in the context of the known NMR and X-ray structures of cytochrome c. Analysis of cross-linked RNase A by LC/MS and MALDI yielded nine modified peptides, four of which were modified twice, as indicated by the isotopic triplets. Although seven of these peptides contained cross-links, few distance constraints were gained due to the fact that the cross-linked products were variations of modification of the same three lysine residues.     

International Intercomparison of Solar UVR Spectral Measurement Systems in Melbourne in 2013

Monitoring ambient solar UVR levels provides information on how much there is in both real time and historically. Quality assurance of ambient measurements of solar UVR is critical to ensuring accuracy and stability and this can be achieved by regular intercomparisons of spectral measurement systems with those of other organizations. In October and November of 2013 a solar UVR spectroradiometer from Public Health England (PHE) was brought to Melbourne for a campaign of intercomparisons with a new Bentham spectrometer of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and one at the Australian Bureau of Meteorology (BOM), supported by New Zealand's National Institute for Water and Atmosphere (NIWA). Given all three spectroradiometers have calibrations that are traceable to various national standards, the intercomparison provides a chance to determine measurement uncertainties and traceability that support UV measurement networks in Australia, New Zealand and the UK. UV Index measurements from all three systems were compared and ratios determined for clear sky conditions when the scans from each instrument were within 2 min of each other. While wavelengths below 305 nm showed substantial differences between the PHE unit and the two other systems, overall the intercomparison results were encouraging, with mean differences in measured UV Index between the BOM/NIWA and those of PHE and ARPANSA of <0.1% and 7.5%, respectively.     

Calibration and use of the Epprecht Rheomat

Summary This paper deals with the calibration and use of an Epprecht Rheomat with particular reference to non Newtonian liquids. A method of calculating accurate rates of shear for non-Newtonian flow is derived using theEuler-Maclaurin sum formula. Some examples are given of the calculation of shear of poly vinyl chlorideplasticiser suspensions.

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Zusammenfassung Die vorliegende Abhandlung befaßt sich mit der Eichung und dem Gebrauch eines Epprecht-Rheomats mit besonderer Hinsicht auf nicht-Newtonische Flüssigkeiten.Ein Verfahren zur exakten Berechnung von Scherwerten für nicht-Newtonische Flüssigkeiten läßt sich aus derEuler-Maclaurinschen Summenformel ableiten.Einige Beispiele zur Berechnung von Scherwerten für Weichmacher von Polyvinylchlorid sind beigefügt.

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Paper presented at the Conference on Experimental Rheology, University of Bradford, April 17–19, 1968.     

Gold nanoparticle-decorated keggin ions/TiO2 photococatalyst for improved solar light photocatalysis

We demonstrate a facile localized reduction approach to synthesizing a Au nanoparticle-decorated Keggin ion/TiO(2) photococatalyst for improved solar light photocatalysis application. This has been achieved by exploiting the ability of TiO(2)-bound Keggin ions to act as a UV-switchable, highly localized reducing agent. Notably, the approach proposed here does not lead to contamination of the resultant cocatalyst with free metal nanoparticles during aqueous solution-based synthesis. The study shows that for Keggin ions (phosphotungstic acid, PTA), being photoactive molecules, the presence of both Au nanoparticles and PTA on the TiO(2) surface in a cocatalytic system can have a dramatic effect on increasing the photocatalytic performance of the composite system, as opposed to a TiO(2) surface directly decorated with metal nanoparticles without a sandwiched PTA layer. The remarkable increase in the photocatalytic performance of these materials toward the degradation of a model organic Congo red dye correlates to an increase of 2.7-fold over that of anatase TiO(2) after adding Au to it and 4.3-fold after introducing PTA along with Au to it. The generalized localized reduction approach to preparing TiO(2)-PTA-Au cocatalysts reported here can be further extended to other similar systems, wherein a range of metal nanoparticles in the presence of different Keggin ions can be utilized. The composites reported here may have wide potential implications toward the degradation of organic species and solar cell applications.     

Synthesis of simple heparanase substrates

Heparanase degrades heparan sulfate (HS) chains on proteoglycans; elevated levels of heparanase expression correlate with tumour cell metastatic potential and vascularity, and reduced post-operative survival of cancer patients. Consequently, heparanase expression is considered a biomarker for cancer detection. Although several heparanase assays have been developed, most require the preparation of heterogeneous, (radio)labelled HS substrates and rely on the separation of enzymatically-degraded products on the basis of molecular size. In studies directed towards the development of a more direct heparanase assay, a series of glucuronides and glycosyl glucuronides were synthesised as putative heparanase substrates. These compounds were designed with various aryl aglycones that could be measured spectrophotometrically upon hydrolysis of the glycosidic linkage by heparanase. It was found that the N-sulfated 4-nitrophenyl glycosyl glucuronide 24 and the N-sulfated methylumbelliferyl glycosyl glucuronide 26 were hydrolysed by recombinant human heparanase. These compounds represent the simplest substrates of heparanase reported to date.     

LC-MS based quantification of 2'-ribosylated nucleosides Ar(p) and Gr(p) in tRNA

RNA nucleosides are often naturally modified into complex non-canonical structures with key biological functions. Here we report LC-MS quantification of the Ar(p) and Gr(p) 2'-ribosylated nucleosides in tRNA using deuterium labelled standards, and the first detection of Gr(p) in complex fungi.     

Impaired pulmonary blood flow distribution in congestive heart failure assessed using synchrotron radiation microangiography

Synchrotron radiation microangiography is a powerful tool for assessing adverse changes in pulmonary vessel density associated with primary pulmonary hypertension (PH). Congestive heart failure (CHF) leads to a `secondary' onset of PH, yet it is unknown whether secondary PH is also associated with reduced vessel density. This study utilized synchrotron radiation to assess both pulmonary vessel density and endothelial function in a Dahl rat model of CHF with secondary PH. High salt‐fed Dahl salt‐sensitive (Dahl‐S) and salt‐resistant (Dahl‐R) rats were anesthetized and microangiography was performed to assess the pulmonary vessel density and vascular responses to (i) sodium nitroprusside (5.0 µg kg^?1 min^?1), (ii) acetylcholine (3.0 µg kg^?1 min^?1) and (iii) ET‐1_A receptor blockade, BQ‐123 (1 mg kg^?1). Dahl‐S rats developed CHF and secondary PH as evident by endothelial dysfunction, impaired vasodilatory responses to acetylcholine, enhanced vasodilatory responses to BQ‐123 and extensive pulmonary vascular remodeling. Consequently, the pulmonary vessel density was adversely reduced. Interestingly, the etiology of secondary PH manifests with structural and functional changes that are comparable with that previously reported for primary PH. One important discrepancy, however, is that ET‐1 modulation of pulmonary vessels is most striking in vessels with a diameter range of 100–200 µm in secondary PH, in contrast to a range of 200–300 µm in primary PH. Such discrepancies should be considered in future studies investigating primary and secondary forms of PH.