Degradation, Harm and Survival in a Women’s Prison:Special Issue on Gendered Violence

This article is derived in in-depth qualitative research in the women’s unit of a male prison in Northern Ireland. The researchers had unprecedented observational and interview access and moved freely within the unit including the punishment block. What follows focuses primarily on the experiences of women and girls, recording their accounts of the impact on their lives of a harsh and neglectful regime. It demonstrates how the institutionalisation of violation and neglect within women’s prisons is often gender specific. Finally, it considers the key research recommendations, noting official responses.

Effect of controlled periodic-based illumination on the photonic efficiency of photocatalytic degradation of methyl orange

The use of controlled periodic illumination with UV LEDs for enhancing photonic efficiency of photocatalytic decomposition processes in water has been investigated using methyl orange as a model compound. The impact of the length of light and dark time periods (T _ON/T _OFF times) on photodegradation and photonic efficiency using a UV LED-illuminated photoreactor has been studied. The results have shown an inverse dependency of the photonic efficiency on duty cycle and a very little effect on T _ON or T _OFF time periods, indicating no effect of rate-limiting steps through mass diffusion or adsorption/desorption in the reaction. For this reactor, the photonic efficiency under controlled periodic illumination (CPI) matches to that of continuous illumination, for the same average UV light intensities. Furthermore, under CPI conditions, the photonic efficiency is inversely related to the average UV light intensity in the reactor, in the millisecond time regime. This is the first study that has investigated the effect of controlled periodic illumination using ultra band gap UV LED light sources in the photocatalytic destruction of dye compounds using titanium dioxide. The results not only enhance the understanding of the effect of periodic illumination on photocatalytic processes but also provide a greater insight to the potential of these light sources in photocatalytic reactions. 

The degradation of microcystin-LR using doped visible light absorbing photocatalysts

Microcystins are one of the primary hepatotoxic cyanotoxins released from cyanobacteria. The presence of these compounds in water has resulted in the death of both humans and domestic and wild animals. Although microcystins are chemically stable titanium dioxide photocatalysis has proven to be an effective process for the removal of these compounds in water. One problem with this process is that it requires UV light and therefore in order to develop effective commercial reactor units that could be powered by solar light it is necessary to utilize a photocatalyst that is active with visible light. In this paper we report on the application of four visible light absorbing photocatalysts for the destruction of microcystin-LR in water. The rhodium doped material proved to be the most effective material followed by a carbon-modified titania. The commercially available materials were both relatively poor photocatalysts under visible radiation while the platinum doped catalyst also displayed a limited activity for toxin destruction. © 2009 Elsevier Ltd. All rights reserved.

Variables to be considered when assessing the photocatalytic destruction of bacterial pathogens

The current study sought to assess the importance of three common variables on the outcome of TiO₂ photocatalysis experiments with bacteria. Factors considered were (a) ability of test species to withstand osmotic pressure, (b) incubation period of agar plates used for colony counts following photocatalysis and (c) chemical nature of suspension medium used for bacteria and TiO₂. Staphylococcus aureus, Escherichia coli, Salmonella ser. Typhimurium and Pseudomonas aeruginosa were found to vary greatly in their ability to withstand osmotic pressure, raising the possibility that osmotic lysis may be contributing to loss of viability in some photocatalytic disinfection studies. Agar plate incubation time was also found to influence results, as bacteria treated with UV light only grew more slowly than those treated with a combination of UV and TiO_2. The chemical nature of the suspension medium used was found to have a particularly pronounced effect upon results. Greatest antibacterial activity was detected when aqueous sodium chloride solution was utilised, with ∼1 × 10⁶ CFU mL^-1 S. aureus being completely killed after 60 min. Moderate activity was observed when distilled water was employed with bacteria being killed after 2 h and 30 min, and no antibacterial activity at all was detected when aqueous tryptone solution was used. Interestingly, the antibacterial activity of UV light on its own appeared to be very much reduced in experiments where aqueous sodium chloride was employed instead of distilled water.