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Electrostatic Interaction and Complex Formation between Gum Arabic and Bovine Serum Albumin
No full textThe interaction of gum arabic (GA) and bovine serum albumin (BSA) has been investigated through turbidity and light scattering intensity measurements and by the use of dynamic light scattering, laser Doppler velocimetry, and isothermal titration calorimetry. It has been shown that GA and BSA can form soluble and insoluble complexes depending on the solution pH and the mixing ratio and is a function of the net charge on the complex. Soluble complexes were obtained when the electrophoretic mobility was greater than ±1. 5 μm s−1 V−1 cm−1. Changes in the value of the isoelectric point of the complexes with mixing ratio and isothermal titration calorimetric data indicated that complexes formed at pHs 3 and 4 consisted of 60 BSA molecules for every GA molecule, while at pH 5 there were 10 BSA molecules per GA molecule. Calorimetric studies also indicated that the interaction occurred in two stages at both pH 3 and pH 4, but that the nature of the interaction at these two pH values was significantly different. This was attributed to differences in the relative magnitude of the positive and negative charges on the BSA and GA, respectively, and possibly due to changes in the BSA conformation. The fact that there is an interaction at pH 5, which is above the isoelectric point of the BSA, is due to the interaction of the carboxylate groups on the GA with positive patches on the BSA or to the charge regulation of the protein−polysaccharide system brought about by changes in dissociation equilibria. Complexation is reduced as the ionic strength of the solvent increases and is prevented at a NaCl concentration of 120 mM
Comparative rheological behavior of hyaluronan from bacterial and animal sources with cross-linked hyaluronan (hylan) in aqueous solution
No full textUsing a variety of rheological techniques, the behavior of hyaluronan (Mw 0.8-2.2 × 106), cross-linked hyaluronan (hylan) (Mw 1.8-12.5 × 106), and Healon (Mw 5 × 106) (a proprietary hyaluronan) was studied over a large range of molecular weights. The object was to study the effect of the cross-links in hylan on the various rheological parameters, in comparison with linear hyaluronan. There are significant differences. The Huggins constant and the critical overlap parameter C*[ ] are considerably lower for hylan and an increase in moduli at low frequencies was observed for hylan compared with the hyaluronan samples at all molecular weights studied. The results point to a difference in structure in dilute solution for hylan due to the ability to form networks, which can be removed by pressure filtration. In contrast, we do not find an increase of the steady shear viscosity and elastic modulus at higher concentrations when a homogeneous entangled network is reached. We attribute this behavior to the semirigid character of the hyaluronan chain and to the predominance of entanglements over the cross-link points present in hylan in the semidilute domain. Due to the higher apparent molecular weights that are possible with hylan structures but not with the hyaluronans currently available, a wider range of applications can be achieved with hylans when viscoelasticity is required, particularly for the viscosupplementation of synovial fluid damaged by osteoarthritis. © 2001 John Wiley & Sons, Inc. Biopolymers 59: 191-204, 200
The Impact of Personality and Religion on Attitudes toward Alcohol among 16–18 year olds in Northern Ireland
No full textBackground: Previous research demonstrates a negative relationship between attitude toward alcohol and religiosity. However, what is less apparent is if this relationship may, at least in part, be a function of individual differences in personality, as previous research has demonstrated a relationship between certain measures of personality and both attitude toward alcohol and attitude toward religiosity. The aim of the present study was to explore the impact of personality and the relative efficacy of different markers of religiosity in predicting attitude toward alcohol among a sample of 16–18 year olds in Northern Ireland. Method: The Francis Scale of Attitude toward Alcohol (Francis, 1992c. Drug and Alcohol Dependence, 31, 45–50) was administered alongside the Abbreviated Revised Eysenck Personality Questionnaire (Francis, Brown, & Philipchalk, 1992. Personality and Individual Differences, 13(4), 443–449), the Francis Scale of Attitude toward Christianity (Francis & Stubbs, 1987. Personality and Individual Differences, 8, 741–743) and measures of frequency of personal prayer and church attendance among a sample of 243 16- to 18-year-old sixth-form students in Northern Ireland. Results and conclusion: The data demonstrate that a more prohibitive attitude toward alcohol was correlated with lower psychoticism scores (tendermindedness) and a more positive attitude toward Christianity. Multiple-regression analyses confirm the importance of attitude toward religion in predicting individual differences in attitude toward alcohol
Women’s Safety Service within the Integrated Domestic Abuse Programme: Perceptions of Service Users
Get PDFThis paper draws on the findings of a qualitative evaluation that examines women's perceptions of the services provided to them whilst their abusers attended an Integrated Domestic Violence Programme (IDAP) in one probation area in the UK. Research focusing on domestic violence programmes has mostly concentrated on the experiences of male perpetrators. As a result, less is known about how women feel about such programmes and the parallel safety services they are supposed to receive. This research seeks to address that weakness by exploring the perceptions of 13 women whose abusers are attending one perpetrator programme. The findings of our study suggest that women are generally negative about perpetrator programmes and require more comprehensive and coordinated services than are routinely made available to them. The paper suggests that women value and need direct and assertive support as well as safety services, and this need is especially pronounced in rural contexts where women can be isolated from mainstream services. The implications of the research to practice with victims of domestic violence are discussed to inform further development of IDAP and similar programmes in the UK and beyond
A comparative study of some properties of cassava (Manihot esculenta, Crantz) and cocoyam (Colocasia esculenta, Linn) starches
Get PDFSome properties of cassava and cocoyam starches were studied and compared with a view to determining the functional applications in food systems for which they are suitable. The starches were compared in terms of their microscopic, thermal, physicochemical and rheological properties. Microscopy revealed smaller granule sizes of cocoyam starch compared with cassava. The amylose content was higher in cocoyam starch (33.3%) than in cassava starch (29.3%). Gelatinization in cassava starch occurred at a lower temperature range (60.11 o -72.67oC) compared with cocoyam (72.96o – 80.25oC) with the endothermic gelatinization enthalpy higher in cocoyam. The swelling power and solubility patterns indicated lower relaxation temperature, higher swelling and solubilization rates in cassava starch compared with cocoyam starch. The pasting characteristics of 8% (db, dry basis) starch slurry showed that cassava had higher peak viscosity but lower stability and setback ratios compared with cocoyam. This indicates that cocoyam starch paste is better in withstanding processing conditions and would present a superior thickening characteristic than cassava starch paste. The flow properties of both starch pastes showed non-Newtonian behaviour and could be best described by the Herschel-Bulkley model. The rate index and yield stress of cocoyam starch paste was higher than that of cassava. The storage modulus of cocoyam starch paste was higher than that of cassava indicating that cocoyam starch paste was more rigid than cassava starch paste. Cassava starch paste exhibited higher paste clarity and freeze-thaw stability than cocoyam starch paste. The properties of cassava and cocoyam starches dictate their food applications
An independently fed log-periodic antenna for directed pulsed radiation
Get PDFThe development of an antenna capable of radiating a band-limited pulse with minimal distortion, negligible loss, and significant directivity is reported. A design was derived by modification of the conventional log-periodic dipole array to permit independent feeding of each dipole. This was modeled with a time-domain integral equation program and iterated to find a design that minimized phase dispersion across the operating band. The optimal design was realized in hardware, using a printed structure to feed the dipoles independently; this was located in the normal plane to prevent distortion of the radiated fields. When tested, the antenna was found to give a good quality radiated pulse in the main beam direction, with weaker and dispersed waveforms in other directions, indicating significant directive gain
Drug policy under New Labour 1997-2010: Prolonging the war on drugs
No full textIn 1997 New Labour came to power with a landslide victory. This period also marked a watershed for illicit drug use which had become so widespread across the UK that it was regarded as a mainstream adolescent experience. However, broadly speaking there were two groups of drug users: one group of young people who selectively used drugs on a recreational and largely non-problematic basis; while another group (usually unemployed and socially excluded), who used whatever drugs they could find in a chaotic and problematic manner. Drug taking had become a normalized activity and criminalization of these drugs seemed unenforceable, out of touch and inappropriate. Inheriting an unworkable 1971 Misuse of Drugs Act 1997 seemed an opportune time for the New Labour government to deliver on its ‘promise of change’ and introduce drug legislation fit for the new millennium. This article reflects upon some of the key policy and legal changes introduced by the New Labour government (1997—2010) to manage drug use and misuse
A Comparison of Methods for Estimating the Tail Index of Heavy-tailed Internet Traffic
No full textMany researchers have discussed the effects of heavy-tailedness in network traffic patterns and shown that Internet traffic flows exhibit characteristics of self-similarity that can be explained by the heavy-tailedness of the various distributions involved. Self-similarity and heavy-tailedness are of great importance for network capacity planning purposes in which researchers are interested in developing analytical methods for analysing traffic characteristics. Designers of computing and telecommunication systems are increasingly interested in employing heavy-tailed distributions to generate workloads for use in simulation although simulations employing such workloads may show unusual characteristics. In this paper, we describe some of the most useful mechanisms for estimating the tail index, particularly for distributions having the power law observed in different contexts in the Internet
Indigenous people, language and criminal justice: the experience of first language Welsh speakers in wales
Get PDFThis article examines the commitment of the criminal justice system (CJS) for England and Wales to respond to the needs of the largest territorially bound linguistic minority group in the UK - Welsh speakers in Wales. The article contextualizes the experience of the Welsh speakers historically, making links with the experience of other indigenous national linguistic minorities worldwide. The importance of language choice is discussed and the reality of linguistic choice within the CJS in Wales is explored in a small scale study with probation staff. Their responses to a brief questionnaire indicate that language choice is not a reality for the majority of Welsh speakers in Wales. The judicial and rehabilitative consequences of this lack of choice are explored. It is argued that a focus on non-discrimination in policy and practice at the international and national level, the vagueness of linguistic rights legislation and the centralization of the CJS in the UK leads to the oppression of Welsh speakers offenders in the criminal justice system in Wales. This article proposes that a passive approach to language choice for indigenous linguistic minorities like the Welsh is unacceptable and that a proactive commitment to linguistically sensitive practice should be adopted on the basis of social justice, equal opportunities and to effectively engage with offenders to protect the public. Nine principles for effective criminal justice practice with Welsh speakers in Wales are proposed which it is argued, have wider applicability with indigenous/substate national linguistic communities worldwide
Optimisation Techniques for Wireless Networks
Get PDFThis paper introduces two new algorithms for the minimum connected dominating set problem. The problem and its relevance to various aspects of wireless network optimisation are briefly outlined followed by a description of the suggested techniques. Results show that these algorithms outperform a number of previous approaches in terms of solution quality and potential for future work is discussed