Azo-linked corner porphyrin systems: synthesis, crystal structures and spectroscopic investigation

1,2-Bis[10,15-di(3,5-di-tert-butyl)phenylporphyrinatonickel(II)-5-yl]diazene was synthesised via copper catalysed coupling of aminated nickel(II) 5,10-diarylporphyrin (“corner porphyrin”) and its X-ray crystal structure was determined. Two different crystals yielded different structures, one with the free meso positions in a trans-like orientation, and the other with a cis-like disposition. The free meso positions of the obtained dimer have been further functionalised while the synthesis of a zinc analogue has so far been unsuccessful. The X-ray crystal structure of the dinitro derivative of the dinickel(II) azoporphyrin was determined, and the structure showed a cis-like disposition of the nitro groups.

Matrix metalloproteinase biosensor based on a porous silicon reflector

Matrix metalloproteinases (MMPs) are proteolytic enzymes important to wound healing. In non-healing wounds, it has been suggested that MMP levels become dysfunctional, hence it is of great interest to develop sensors to detect MMP biomarkers. This study presents the development of a label-free optical MMP biosensor based on a functionalised porous silicon (pSi) thin film. The biosensor is fabricated by immobilising a peptidomimetic MMP inhibitor in the porous layer using hydrosilylation followed by amide coupling. The binding of MMP to the immobilised inhibitor translates into a change of effective optical thickness (EOT) over the time. We investigate the effect of surface functionalisation on the stability of pSi surface and evaluate the sensing performance. We successfully demonstrate MMP detection in buffer solution and human wound fluid at physiologically relevant concentrations. This biosensor may find application as a point-of-care device that is prognostic of the healing trajectory of chronic wounds.

Corner and finger formation in Hele-Shaw flow with kinetic undercooling regularisation

We examine the effect of a kinetic undercooling condition on the evolution of a free boundary in Hele--Shaw flow, in both bubble and channel geometries. We present analytical and numerical evidence that the bubble boundary is unstable and may develop one or more corners in finite time, for both expansion and contraction cases. This loss of regularity is interesting because it occurs regardless of whether the less viscous fluid is displacing the more viscous fluid, or vice versa. We show that small contracting bubbles are described to leading order by a well-studied geometric flow rule. Exact solutions to this asymptotic problem continue past the corner formation until the bubble contracts to a point as a slit in the limit. Lastly, we consider the evolving boundary with kinetic undercooling in a Saffman--Taylor channel geometry. The boundary may either form corners in finite time, or evolve to a single long finger travelling at constant speed, depending on the strength of kinetic undercooling. We demonstrate these two different behaviours numerically. For the travelling finger, we present results of a numerical solution method similar to that used to demonstrate the selection of discrete fingers by surface tension. With kinetic undercooling, a continuum of corner-free travelling fingers exists for any finger width above a critical value, which goes to zero as the kinetic undercooling vanishes. We have not been able to compute the discrete family of analytic solutions, predicted by previous asymptotic analysis, because the numerical scheme cannot distinguish between solutions characterised by analytic fingers and those which are corner-free but non-analytic.

Corner detection in images under different noise levels

Corner detection has shown its great importance in many computer vision tasks. However, in real-world applications, noise in the image strongly affects the performance of corner detectors. Few corner detectors have been designed to be robust to heavy noise by now, partly because the noise could be reduced by a denoising procedure. In this paper, we present a corner detector that could find discriminative corners in images contaminated by noise of different levels, without any denoising procedure. Candidate corners (i.e., features) are firstly detected by a modified SUSAN approach, and then false corners in noise are rejected based on their local characteristics. Features in flat regions are removed based on their intensity centroid, and features on edge structures are removed using the Harris response. The detector is self-adaptive to noise since the image signal-to-noise ratio (SNR) is automatically estimated to choose an appropriate threshold for refining features. Experimental results show that our detector has better performance at locating discriminative corners in images with strong noise than other widely used corner or keypoint detectors.

Vibrational spectroscopy of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes : (Part 10) The infrared and Raman characteristics of phthalocyanine in heteroleptic bis(phthalocyaninato) rare earth complexes with decreased molecular symmetry

The infrared (IR) spectroscopic data for a series of eleven heteroleptic bis(phthalocyaninato) rare earth complexes MIII(Pc)[Pc(α-OC5H11)4] (M = Sm–Lu, Y) [H2Pc = unsubstituted phthalocyanine, H2Pc(α-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected with 2 cm−1 resolution. Raman spectroscopic properties in the range of 500–1800 cm−1 for these double-decker molecules have also been comparatively studied using laser excitation sources emitting at 632.8 and 785 nm. Both the IR and Raman spectra for M(Pc)[Pc(α-OC5H11)4] are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues due to the decreased molecular symmetry of these double-decker compounds, namely C4. For this series, the IR Pc√− marker band appears as an intense absorption at 1309–1317 cm−1, attributed to the pyrrole stretching. With laser excitation at 632.8 nm, Raman vibrations derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 are selectively intensified. In contrast, when excited with laser radiation of 785 nm, the ring radial vibrations of isoindole moieties and dihedral plane deformations between 500 and 1000 cm−1 for M(Pc)[Pc(α-OC5H11)4] intensify to become the strongest scatterings. Both techniques reveal that the frequencies of pyrrole stretching, isoindole breathing, isoindole stretchings, aza stretchings and coupling of pyrrole and aza stretchings depend on the rare earth ionic size, shifting to higher energy along with the lanthanide contraction due to the increased ring-ring interaction across the series. The assignments of the vibrational bands for these compounds have been made and discussed in relation to other unsubstituted and substituted bis(phthalocyaninato) rare earth analogues, such as M(Pc)2 and M(OOPc)2 [H2OOPc = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine].

Crystallographic characterization of the first reported crystalline form of the potent hallucinogen (R)-2-amino-1-(8-bromobenzo[1,2-b;5,4-b']difuran-4-yl)propane or `bromodragonfly': the 1:1 anhydrous proton-transfer compound with 3,5-dinitrosalicylic acid

The 1:1 proton-transfer compound of the potent substituted amphetamine hallucinogen (R)-1-(8-bromobenzo[1,2-b; 4,5-b']difuran-4-yl)-2-aminopropane (common trivial name 'bromodragonfly') with 3,5-dinitrosalicylic acid, 1-(8-bromobenzo[1,2-b;4,5-b']difuran-4-yl)-2-mmoniopropane 2-carboxy-4,6-dinitrophenolate, C13H13BrNO2+ C7H3N2O7- forms hydrogen-bonded cation-anion chain substructures comprising undulating head-to-tail anion chains formed through C(8) carboxyl O-H...O(nitro) associations and incorporating the aminium groups of the cations. The intra-chain cation-anion hydrogen-bonding associations feature proximal cyclic R33(8) interactions involving both a N+-H...O(phenolate) and the carboxyl O--H...O(nitro)associations. Also present are aromatic pi-pi ring interactions [minimum ring centroid separation, 3.566(2)A; inter-plane dihedral angle, 5.13(1)deg]. A lateral hydrogen-bonding interaction between the third aminium proton and a carboxyl O acceptor link the chain substructures giving a two-dimensional sheet structure. This determination represents the first of any form of this compound and confirms that it has the (R) absolute configuration. The atypical crystal stability is attributed both to the hydrogen-bonded chain substructures provided by the anions, which accommodate the aminium proton-donor groups of the cations and give cross-linking, and to the presence of cation--anion aromatic ring pi-pi interactions.

Peripheral higher order aberrations in emmetropes and myopes

Purpose: Poor image quality in the peripheral field may lead to myopia. Most studies measuring the higher order aberrations in the periphery have been restricted to the horizontal visual field. The purpose of this study was to measure higher order monochromatic aberrations across the central 42º horizontal x 32º vertical visual fields in myopes and emmetropes. ---------- Methods: We recruited 5 young emmetropes with spherical equivalent refractions +0.17 ± 0.45D and 5 young myopes with spherical equivalent refractions -3.9 ± 2.09D. Measurements were taken with a modified COAS-HD Hartmann-Shack aberrometer (Wavefront Sciences Inc). Measurements were taken while the subjects looked at 38 points arranged in a 7 x 6 matrix (excluding four corner points) through a beam splitter held between the instrument and the eye. A combination of the instrument’s software and our own software was used to estimate OSA Zernike coefficients for 5mm pupil diameter at 555nm for each point. The software took into account the elliptical shape of the off-axis pupil. Nasal and superior fields were taken to have positive x and y signs, respectively. ---------- Results: The total higher order RMS (HORMS) was similar on-axis for emmetropes (0.16 ± 0.02 μm) and myopes (0.17 ± 0.02 μm). There was no common pattern for HORMS for emmetropes across the visual field where as 4 out of 5 myopes showed a linear increase in HORMS in all directions away from the minimum. For all subjects, vertical and horizontal comas showed linear changes across the visual field. The mean rate of change of vertical coma across the vertical meridian was significantly lower (p = 0.008) for emmetropes (-0.005 ± 0.002 μm/deg) than for myopes (-0.013 ± 0.004 μm/deg). The mean rate of change of horizontal coma across the horizontal meridian was lower (p = 0.07) for emmetropes (-0.006 ± 0.003 μm/deg) than myopes (-0.011 ± 0.004 μm/deg). ---------- Conclusion: We have found differences in patterns of higher order aberrations across the visual fields of emmetropes and myopes, with myopes showing the greater rates of change of horizontal and vertical coma.

Chemical functionalities of high and low sulfur Australian coals : a case study using micro attenuated total reflectance–fourier transform infrared (ATR–FTIR) spectrometry

The macerals in bituminous coals with varying organic sulfur content from the Early Permian Greta Coal Measures at three locations (Southland Colliery, Drayton Colliery and the Cranky Corner Basin), in and around the Sydney Basin (Australia), have been studied using light-element electron microprobe (EMP) analysis and micro-ATR–FTIR. Electron microprobe analysis of individual macerals reveals that the vitrinite in both the Cranky Corner Basin and Drayton Colliery (Puxtrees seam) samples have similar carbon contents (ca. 78% C in telocollinite), suggesting that they are of equivalent rank. However, the Cranky Corner coals have anomalously low vitrinite reflectance (down to 0.45%) vs. the Drayton materials (ca. 0.7%). They also have very high organic S content (3–6.5%) and lower O content (ca. 10%) than the equivalent macerals in the Drayton sample (0.7% S and 15.6% O). A study was carried out to investigate the impacts of the high organic S on the functional groups of the macerals in these two otherwise iso-rank, stratigraphically-equivalent seams. An iso-rank low-S coal from the overlying Wittingham Coal Measures near Muswellbrook and coals of slightly higher rank from the Greta Coal Measures at Southland Colliery near Cessnock were also evaluated using the same techniques to extend the data set. Although the telocollinite in the Drayton and Cranky Corner coals have very similar carbon content (ca.78% C), the ATR–FTIR spectra of the vitrinite and inertinite macerals in these respectively low S and high S coals show some distinct differences in IR absorbance from various aliphatic and aromatic functional groups. The differences in absorbance of the aliphatic stretching bands (2800–3000 cm−1) and the aromatic carbon (CC) peak at 1606 cm−1 are very obvious. Compared to that of the Drayton sample (0.7% S and 15% O), the telocollinite of the Cranky Corner coal (6% S and 10% O) clearly shows: (i) less absorbance from OH groups, represented by a broad region around 3553 cm−1, (ii) much stronger aliphatic C–H absorbance (stretching modes around 3000–2800 cm−1 and bending modes around 1442 cm−1) and (iii) less absorbance from aromatic carbon functional groups (peaking at 1606 cm−1). Evaluation of the iso-rank Drayton and Cranky Corner coals shows that: (i) the aliphatic C–H absorbances decrease with increasing oxygen content but increase with increasing organic S content and (ii) the aromatic H to aliphatic H ratio (Har/Hali) for the telocollinite increases with (organic) O%, but decreases progressively with increasing organic S. The high organic S content in the maceral appears to be accompanied by a greater proportion of aliphatic functional groups, possibly as a result of some of the O within maceral ring structures in the high S coal samples being replaced.

Azo- and butadiyne-linked 5,10-diarylporphyrins

Porphyrins are one of Nature’s essential building blocks that play an important role in several biological systems including oxygen transport, photosynthesis, and enzymes. Their capacity to absorb visible light, facilitate oxidation and reduction, and act as energy- and electron-transfer agents, in particular when several are held closely together, is of interest to chemists who seek to mimic Nature and to make and use these compounds in order to synthesise novel advanced materials. During this project 26 new 5,10-diarylsubstituted porphyrin monomers, 10 dimers, and 1 tetramer were synthesised. The spectroscopic and structural properties of these compounds were investigated using 1D/2D 1H NMR, UV/visible, ATR-IR and Raman spectroscopy, mass spectrometry, X-ray crystallography, electrochemistry and gel permeation chromatography. Nitration, amination, bromination and alkynylation of only one as well as both of the meso positions of the porphyrin monomers have resulted in the expansion of the synthetic possibilities for the 5,10-diarylsubstituted porphyrins. The development of these new porphyrin monomers has led to the successful synthesis of new azo- and butadiyne-linked dimers. The functionalisation of these compounds was investigated, in particular nitration, amination, and bromination. The synthesised dimers containing the azo bridge have absorption spectra that show a large split in the Soret bands and intense Q-bands that have been significantly redshifted. The butadiyne dimers also have intense, red-shifted Q-bands but smaller Soret band splittings. Crystal structures of two new azoporphyrins have been acquired and compared to the azoporphyrin previously synthesised from 5,10,15- triarylsubstituted porphyrin monomers. A completely new cyclic porphyrin oligomer (CPO) was synthesised comprising four porphyrin monomers linked by azo and butadiyne bridges. This is the first cyclic tetramer that has both the azo and butadiyne linking groups. The absorption spectrum of the tetramer exhibits a large Soret split making it more similar to the azo- dimers than the butadiyne-linked dimers. The spectroscopic characteristics of the synthesised tetramer have been compared to the characteristics of other cyclic porphyrin tetramers. The collected data indicate that the new synthesised cyclic tetramer has a more efficient ð-overlap and a better ground state electronic communication between the porphyrin rings.

On democracy

If one clear argument emerged from my doctoral thesis in political science, it is that there is no agreement as to what democracy is. There are over 40 different varieties of democracy ranging from those in the mainstream with subtle or minute differences to those playing by themselves in the corner. And many of these various types of democracy are very well argued, empirically supported, and highly relevant to certain polities. The irony is that the thing which all of these democratic varieties or the ‘basic democracy’ that all other forms of democracy stem from, is elusive. There is no international agreement in the literature or in political practice as to what ‘basic democracy’ is and that is problematic as many of us use the word ‘democracy’ every day and it is a concept of tremendous importance internationally. I am still uncertain as to why this problem has not been resolved before by far greater minds than my own, and it may have something to do with the recent growth in democratic theory this past decade and the innovative areas of thought my thesis required, but I think I’ve got the answer. By listing each type of democracy and filling the column next to this list with the literature associated with these various styles of democracy, I amassed a large and comprehensive body of textual data. My research intended to find out what these various styles of democracy had in common and to create a taxonomy (like the ‘tree of life’ in biology) of democracy to attempt at showing how various styles of democracy have ‘evolved’ over the past 5000 years.ii I then ran a word frequency analysis program or a piece of software that counts the 100 most commonly used words in the texts. This is where my logic came in as I had to make sense of these words. How did they answer what the most fundamental commonalities are between 40 different styles of democracy? I used a grounded theory analysis which required that I argue my way through these words to form a ‘theory’ or plausible explanation as to why these particular words and not others are the important ones for answering the question. It came down to the argument that all 40 styles of democracy analysed have the following in common 1) A concept of a citizenry. 2) A concept of sovereignty. 3) A concept of equality. 4) A concept of law. 5) A concept of communication. 6) And a concept of selecting officials. Thus, democracy is a defined citizenry with its own concept of sovereignty which it exercises through the institutions which support the citizenry’s understandings of equality, law, communication, and the selection of officials. Once any of these 6 concepts are defined in a particular way it creates a style of democracy. From this, we can also see that there can be more than one style of democracy active in a particular government as a citizenry is composed of many different aggregates with their own understandings of the six concepts.

Multiple camera management using wide baseline matching

Camera calibration information is required in order for multiple camera networks to deliver more than the sum of many single camera systems. Methods exist for manually calibrating cameras with high accuracy. Manually calibrating networks with many cameras is, however, time consuming, expensive and impractical for networks that undergo frequent change. For this reason, automatic calibration techniques have been vigorously researched in recent years. Fully automatic calibration methods depend on the ability to automatically find point correspondences between overlapping views. In typical camera networks, cameras are placed far apart to maximise coverage. This is referred to as a wide base-line scenario. Finding sufficient correspondences for camera calibration in wide base-line scenarios presents a significant challenge. This thesis focuses on developing more effective and efficient techniques for finding correspondences in uncalibrated, wide baseline, multiple-camera scenarios. The project consists of two major areas of work. The first is the development of more effective and efficient view covariant local feature extractors. The second area involves finding methods to extract scene information using the information contained in a limited set of matched affine features. Several novel affine adaptation techniques for salient features have been developed. A method is presented for efficiently computing the discrete scale space primal sketch of local image features. A scale selection method was implemented that makes use of the primal sketch. The primal sketch-based scale selection method has several advantages over the existing methods. It allows greater freedom in how the scale space is sampled, enables more accurate scale selection, is more effective at combining different functions for spatial position and scale selection, and leads to greater computational efficiency. Existing affine adaptation methods make use of the second moment matrix to estimate the local affine shape of local image features. In this thesis, it is shown that the Hessian matrix can be used in a similar way to estimate local feature shape. The Hessian matrix is effective for estimating the shape of blob-like structures, but is less effective for corner structures. It is simpler to compute than the second moment matrix, leading to a significant reduction in computational cost. A wide baseline dense correspondence extraction system, called WiDense, is presented in this thesis. It allows the extraction of large numbers of additional accurate correspondences, given only a few initial putative correspondences. It consists of the following algorithms: An affine region alignment algorithm that ensures accurate alignment between matched features; A method for extracting more matches in the vicinity of a matched pair of affine features, using the alignment information contained in the match; An algorithm for extracting large numbers of highly accurate point correspondences from an aligned pair of feature regions. Experiments show that the correspondences generated by the WiDense system improves the success rate of computing the epipolar geometry of very widely separated views. This new method is successful in many cases where the features produced by the best wide baseline matching algorithms are insufficient for computing the scene geometry.

Bis(4-carbamoylpiperidinium)biphenyl-4,4'-disulfonate

In the title isonipecotamide salt 2C6H13N2O+.C12H8O6S22-,the asymmetric unit comprises one biphenyl-4,4'-disulfonate dianion which lies across a crystallographic inversion centre and another in a general position [dihedral angle between the two phenyl rings is 37.1(1)deg], together with three isonipecotamide cations. Two of these cations give a cyclic homomeric amide-amide dimer interaction [graph set R2/2(8)],the other giving a similar dimeric interaction but across an inversion centre, both dimers then forming lateral cyclic R2/4(8) pyrimidinium N-H...O interactions. These units are linked longitudinally to the sulfonate groups of the dianions through piperidinium N-H...O hydrogen bonds, giving a three-dimensional framework structure.

Smoothly attaching bow flows with constant vorticity

The free surface flow of a finite depth fluid past a semi-infinite body is considered. The fluid is assumed to have constant vorticity throughout and the free surface is assumed to attach smoothly to the front face of the body. Numerical solutions are found using a boundary integral method in the physical plane and it is shown that solutions exist for all supercritical Froude numbers. The related problem of the cusp-like flow due to a submerged sink in a corner is also considered. Vorticity is included in the flow and it is shown that the behaviour of the solutions is qualitatively the same as that found in the problem described above.

2,4,6-Trinitro-N-[4-(phenyldiazenyl)phenyl)phenyl]aniline

The title compound, C18H12N6O6 was prepared from the reaction of 4-(phenyldiazenyl)aniline (aniline yellow) with picrylsulfonic acid. The dihedral angle formed by the two benzene rings of the diphenyldiazenyl ring system 6.55(13)deg. and that formed by the rings of the picrate-aniline ring system is 48.76(12)deg. The molecule contains an intramolecular aniline-nitro N-H...O hydrogen bond.