ORCID Profile
0000-0003-0842-4302
Current Organisations
University of Southampton
,
University of Portsmouth
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Publisher: American Chemical Society (ACS)
Date: 07-10-2005
DOI: 10.1021/CI050056I
Abstract: We discuss models fit to data collected by Duffy and Jorgensen to predict solvation free energies and partition equilibria of drugs, organic molecules, aromatic heterocycles, and other molecules. These data were originally examined using linear regression, but here more recently developed statistical models are applied. The data set is complicated due to the presence of discrepant observations and also curvature in the response. In some cases it is possible to discard a small number of the observations to get good fit to the data, but, in others, discarding an increasing proportion of the observations does not improve the fit. Our general preference is to use robust parameter estimation which downweights to reduce the influence of discrepant observations on the fitted models. Models are selected for four responses using linear or more complicated representations of the explanatory variables, such as cubic polynomials, B-splines, or smoothers via generalized additive models (GAMs). Variables are chosen using the traditional approach of formal tests to assess contribution to the fit of a model, and res ling methods including bootstrap are also considered to assess the prediction error for given models. Results of our analysis indicate that GAMs are an improvement on linear models for describing the data and making predictions. In general robust regression models and GAMs have the smallest conditional expected loss of prediction over the four responses. In addition, robust regression models offer the advantage of identifying molecules that perform poorly in the fit. In general, models were identified that yielded an improvement of approximately 50% in the conditional expected loss of prediction compared with the original parametrization of Duffy and Jorgensen. It was also found that the use of cross-validation to compare models was unreliable, and bootstrapping is preferred.
Publisher: Elsevier BV
Date: 2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SC51023A
Publisher: Springer Science and Business Media LLC
Date: 10-05-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 04-02-2003
DOI: 10.1039/B210847J
Abstract: The crystal structures of anion complexes of two nitroaromatic functionalised isophthalamides are reported the structures reveal assembly around anions in the solid-state and in the case of the fluoride complex of receptor 2, the formation of a double helix.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SC02128B
Abstract: Chemical scientists’ experiences with LabTrove.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CP02144J
Abstract: Vibrational Sum Frequency Spectroscopy (VSFS) was employed to study adsorbing films of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) at the aqueous solution-air interface. The surface of the solution is strongly influenced by the presence of crown ether species. Changes in the orientation of NB15C5 were monitored as a function of solution concentration, by targeting the ratio of peak intensities of the CN and NO(2) vibrational modes. The water of hydration has also been probed as a function of crown concentration, salt concentration, and temperature. The latter study strongly suggests that the surface can be treated as a charged interface, and that the associated ordered water decreases with increasing ionic strength of the bulk solution.
Publisher: IEEE
Date: 11-2019
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.SCITOTENV.2022.156704
Abstract: Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia. Using an inductive method, 21 research questions emerged under five non-predefined key themes, grouping them according to which: (1) characterise marine plastic pollution in Southeast Asia (2) explore its movement and fate across the region (3) describe the biological and chemical modifications marine plastic pollution undergoes (4) detail its environmental, social, and economic impacts and, finally, (5) target regional policies and possible solutions. Questions relating to these research priority areas highlight the importance of better understanding the fate of marine plastic pollution, its degradation, and the impacts and risks it can generate across communities and different ecosystem services. Knowledge of these aspects will help support actions which currently suffer from transboundary problems, lack of responsibility, and inaction to tackle the issue from its point source in the region. Being profoundly affected by marine plastic pollution, Southeast Asian countries provide an opportunity to test the effectiveness of innovative and socially inclusive changes in marine plastic governance, as well as both high and low-tech solutions, which can offer insights and actionable models to the rest of the world.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CP00604A
Abstract: The surface of aqueous solutions of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) has been studied using the surface sensitive technique vibrational sum frequency spectroscopy (VSFS). The NO, CN, COC and CH vibrational modes of these compounds at the air-water interface as well as OH vibrational modes of the surface water hydrating this compound have been targeted in order to obtain molecular information about arrangement and conformation of the adsorbed crown ether molecules at the air-water interface. The CH(2) vibrational modes of crown ethers have been identified and found to be split due to interaction with ether oxygen. The spectra provide evidence for the existence of a protonated crown complex moiety at the surface leading to the appearance of strongly ordered water species. The interfacial water species are influenced by the resulting charged interface and by the strong Zundel polarizability due to tunneling of the proton species between equivalent sites within the crown ring.
Publisher: Frontiers Media SA
Date: 06-08-2020
Publisher: Public Library of Science (PLoS)
Date: 23-07-2013
Publisher: Springer Science and Business Media LLC
Date: 11-10-2022
DOI: 10.1007/S00769-022-01515-W
Abstract: This short article discusses the units of rate constants as used in chemical kinetics and, in particular, the aspect of non-integral powers of base units, which some might find unusual for units in the SI system. In many ways the fact that the units of the rate constants as usually defined convey information about the order of the reaction or reactions involved is very useful, but in other ways having the same (or at least very similar) quantity that has different units under different conditions is not so desirable. Furthermore, just as with chemical equilibrium constants, taking functions of the rate constant (such as the logarithm when representing the Arrhenius equation in the form ln $$k\\,{\\text {vs.}}\\,1/T$$ k vs. 1 / T ) needs special attention. Here we examine a possible alternative definition of rate constants in terms of an explicit ratio to the concentration standard state and although we acknowledge that this approach unlikely to be adopted by the community, it serves as a basis to discuss the meaning of rate constants.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5SC03932K
Abstract: A QSAR analysis of the transmembrane anion transport activity of 43 synthetic tambjamine analogs allowed rationalization of this activity according to their lipophilicity and structural parameters.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2012
End Date: 2015
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2006
End Date: 2008
Funder: Biotechnology and Biological Sciences Research Council
View Funded Activity