The underwater separation of diamantiferous marine gravels

Includes bibliography.Three underwater separation devices have been designed, constructed, tested and analysed to determine their suitability for the underwater separation of diamantiferous marine gravels. The research facility where the devices were tested was constructed at the University of Cape Town's Hydrotransport Research facility. The first device tested was a converging elutriator which separates the oversize gravel from the smaller diamond-bearing gravel, using their varying particle settling velocities in an upward flowing fluid. The cyclosieve and spirosieve are two other choices that both use rotational flow to create a centrifugal force, which forces the gravel onto a screening surface. The test work carried out investigated the effect of various variable parameters on the separation efficiency of each device

Synergies, tensions and challenges in HIV prevention, treatment and cure research: exploratory conversations with HIV experts in South Africa

Background: The ethical concerns associated with HIV prevention and treatment research have been widely explored in South Africa over the past 3 decades. However, HIV cure research is relatively new to the region and significant ethical and social challenges are anticipated. There has been no published empirical enquiry in Africa into key informant perspectives on HIV cure research. Consequently, this study was conducted to gain preliminary data from South African HIV clinicians, researchers and activists. Methods: In-depth interviews were conducted on a purposive sample of fourteen key informants in South Africa. Audiotaped interviews were transcribed verbatim with concurrent thematic analysis. The perspectives of HIV clinicians, researchers and activists were captured. Analyst triangulation occurred as the data were analysed by three authors independently. Results: The rapid evolution of HIV cure research agendas was prominent with participants expressing some concern that the global North was driving the cure agenda. Participants described a symbiotic relationship between cure, treatment and prevention research necessitating collaboration. Assessing and managing knowledge and expectations around HIV cure research emerged as a central theme related to challenges to constructing ‘cure’ - how patients understand the idea of cure is important in explaining the complexity of cure research especially in the South African context where understanding of science is often challenging. Managing expectations and avoiding curative misconception will have implications for consent processes. Unique strategies in cure research could include treatment interruption, which has the potential to create therapeutic and ethical conflict and will be perceived as a significant risk. Ethical challenges in cure research will impact on informed consent and community engagement. Conclusions: It was encouraging to note the desire for synergy amongst researchers and clinicians working in the fields of prevention, treatment and cure. Translation of complex HIV cure science into lay language is critical. Moving forward, RECs must be adequately constituted with scientific expertise and community representation when reviewing cure protocols. It is hoped that knowledge and resource sharing in the context of collaboration between research scientists working in cure and those working in treatment and prevention will accelerate progress towards cur

Self-harm in young people: a randomised control trial comparing mentalization based treatment against treatment as usual

Objective This thesis aims to explore self-harm in young people in terms of its epidemiology, longitudinal outcome and treatment. Due to close associations between self-harm and personality disorder (PD) and depression, the thesis also aim to better understand the stability of PD from adolescence into adulthood as well as the links between depression and PD into adulthood. Further this thesis aims to examine the differences between self-harmers and non-self-harmers. The final aim to examine whether mentalization-based treatment for adolescents (MBT-A) will be more effective than treatment as usual (TAU) for adolescents who harm themselves. Method Four systematic literature reviews were done to explore the longitudinal outcome of self-harm, the treatment of adolescent self-harm, the stability of adolescent personality disorder into adulthood and the longitudinal outcome and interplay between depression and personality disorder. A cross-section analysis was conducted to compare a self-harming group against two non-self-harming control groups. Finally a randomised control trial (RCT) was conducted, comparing MBT-A against TAU for self-Harming adolescents in terms of reduction in self-harm and depression. Results The outcome of literature reviews are discussed in the thesis. The cross-sectional analysis found that the self-harm group demonstrated significantly more borderline personality disorder traits, more avoidant attachment and worse scores in terms of mentalization. The self-harm group demonstrated more personality pathology in general on most of the personality domains as well as more history of childhood abuse. MBT-A was more effective than TAU in reducing self-harm and depression. This superiority was explained by improved mentalization and reduced attachment avoidance and reflected improvement in emergent borderline personality disorder symptoms and traits

Consent for critical care research after death from COVID-19: Arguments for a waiver

Pandemics challenge clinicians and scientists in many ways, especially when the virus is novel and disease expression becomes variable or unpredictable. Under such circumstances, research becomes critical to inform clinical care and protect future patients. Given that severely ill patients admitted to intensive care units are at high risk of mortality, establishing the cause of death at a histopathological level could prove invaluable in contributing to the understanding of COVID-19. Postmortem examination including autopsies would be optimal. However, in the context of high contagion and limited personal protective equipment, full autopsies are not being conducted in South Africa (SA). A compromise would require tissue biopsies and samples to be taken immediately after death to obtain diagnostic information, which could potentially guide care of future patients, or generate hypotheses for finding needed solutions. In the absence of an advance written directive (including a will or medical record) providing consent for postmortem research, proxy consent is the next best option. However, obtaining consent from distraught family members, under circumstances of legally mandated lockdown when strict infection control measures limit visitors in hospitals, is challenging. Their extreme vulnerability and emotional distress make full understanding of the rationale and consent process difficult either before or upon death of a family member. While it is morally distressing to convey a message of death telephonically, it is inhumane to request consent for urgent research in the same conversation. Careful balancing of the principles of autonomy, non-maleficence and justice becomes an ethical imperative. Under such circumstances, a waiver of consent, preferably followed by deferred proxy consent, granted by a research ethics committee in keeping with national ethics guidance and legislation, would fulfil the basic premise of care and research: first do no harm. This article examines the SA research ethics framework, guidance and legislation to justify support for a waiver of consent followed by deferred proxy consent, when possible, in urgent research after death to inform current and future care to contain the pandemic in the public interest

Comorbidity in context: Part 1. Medical considerations around HIV and tuberculosis during the COVID-19 pandemic in South Africa

Infectious diseases pandemics have devastating health, social and economic consequences, especially in developing countries such as South Africa. Scarce medical resources must often be rationed effectively to contain the disease outbreak. In the case of COVID-19, even the best-resourced countries will have inadequate intensive care facilities for the large number of patients needing admission and ventilation. The scarcity of medical resources creates the need for national governments to establish admission criteria that are evidence-based and fair. Questions have been raised whether infection with HIV or tuberculosis (TB) may amplify the risk of adverse COVID-19 outcomes and therefore whether these conditions should be factored in when deciding on the rationing of intensive care facilities. In light of these questions, clinical evidence regarding inclusion of these infections as comorbidities relevant to intensive care unit admission triage criteria is investigated in the first of a two-part series of articles. There is currently no evidence to indicate that HIV or TB infection on their own predispose to an increased risk of infection with SARS-CoV-2 or worse outcomes for COVID-19. It is recommended that, as for other medical conditions, validated scoring systems for poor prognostic factors should be applied. A subsequent article examines the ethicolegal implications of limiting intensive care access of persons living with HIV or TB

Comorbidity in context: Part 2. Ethicolegal considerations around HIV and tuberculosis during the COVID-19 pandemic in South Africa

The COVID-19 pandemic has brought discussions around the appropriate and fair rationing of scare resources to the forefront. This is of special importance in a country such as South Africa (SA), where scarce resources interface with high levels of need. A large proportion of the SA population has risk factors associated with worse COVID-19 outcomes. Many people are also potentially medically and socially vulnerable secondary to the high levels of infection with HIV and tuberculosis (TB) in the country. This is the second of two articles. The first examined the clinical evidence regarding the inclusion of HIV and TB as comorbidities relevant to intensive care unit (ICU) admission triage criteria. Given the fact that patients with HIV or TB may potentially be excluded from admission to an ICU on the basis of an assumption of lack of clinical suitability for critical care, in this article we explore the ethicolegal implications of limiting ICU access of persons living with HIV or TB. We argue that all allocation and rationing decisions must be in terms of SA law, which prohibits unfair discrimination. In addition, ethical decision-making demands accurate and evidence-based strategies for the fair distribution of limited resources. Rationing decisions and processes should be fair and based on visible and consistent criteria that can be subjected to objective scrutiny, with the ultimate aim of ensuring accountability, equity and fairness

Excitation dependent Fano-like interference effects in plasmonic silver nanorods

Surface plasmon resonances in metal nanoparticles are an emerging technology platform for nano-optics applications from sensing to solar energy conversion. The electromagnetic near field associated with these resonances arises from modes determined by the shape, size, and composition of the metal nanoparticle. When coupled in the near field, multiple resonant modes can interact to give rise to interference effects offering fine control of both the spectral response and spatial distribution of fields near the particle. Here, we present an examination of experimental electron energy loss spectroscopy (EELS) of silver nanorod monomer surface plasmon modes and present an explanation of observed spatial amplitude modulation of the Fabry-Pérot resonance modes of these silver nanorods using electrodynamics simulations. For these simulations, we identify differences in spectral peak symmetry in light scattering and electron spectroscopies (EELS and cathodoluminescence) and analyze the distinct near-field responses of silver nanorods to plane-wave light and electron beam excitation in terms of a coupled oscillator model. Effects of properties of the material and the incident field are evaluated, and the spatially resolved EELS signals are shown to provide a signature for assessing Fano-like interference effects in silver nanorods. These findings outline key considerations and challenges for interpreting electron microscopy data on plasmonic nanoparticles for understanding nanoscale optics and for characterization and design of photonic devices.S.M.C. acknowledges support of a Gates Cambridge Scholarship. D.R. acknowledges support from the Royal Society's Newton International Fellowship scheme. We acknowledge the use of computing facilities provided by CamGrid. Parts of this work were also performed using the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council. We thank F.J. de la Peña for helpful discussions on the use of hyperspy. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Program (Grant No. FP7/2007-2013)/ERC Grant Agreement No. 291522-3DIMAGE. Data on rod “B” were acquired by one of us (D. Rossouw) with support of a NSERC Discovery Grant (G. A. Botton) at the Canadian Centre for Electron Microscopy, a national facility supported by NSERC and McMaster University. We thank G. A. Botton for access to data on rod “B” and for helpful comments on this manuscript. P.A.M. also acknowledges funding from the European Union's Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference No. 312483-ESTEEM2)

Introduction to Mentalization-Based Approaches for Parents, Children, Youths, and Families

Family members mentalize when they try to understand each other's behavior on the basis of intentional mental states. This article aims to introduce and briefly describe how the concept of mentalization can provide a useful framework for clinicians to understand psychopathology of children, youths, and families. The authors further outline how mentalization-based techniques and interventions can be applied to build epistemic trust and to reestablish mentalizing in families by presenting clinical vignettes of initial sessions from various clinical settings in the United Kingdom and Germany. The article concludes with a brief summary about the current evidence for mentalization-based interventions with children, adolescents, and families and provides an outlook for future clinical and research work

Ethical challenges in developing an educational video to empower potential participants during consent processes in future HIV cure research in South Africa

Obtaining consent for HIV research is complex, particularly in low- and middle-income countries. Low levels of education, complexity of science and research processes, confusion about basic elements of research, and socio-economic conditions that make access to medical care difficult have collectively led to concerns about the adequacy of the consent process. Given the exponential growth of HIV prevention and treatment research in South Africa, HIV researchers are increasingly facing challenges obtaining authentic informed consent from potential participants. It is anticipated that HIV cure research, despite being in its infancy in South Africa, will introduce a new discourse into a population that is often struggling to understand the differences between ‘cure’, ‘preventive and therapeutic vaccines’ and other elements of the research process. Coupled with this, South Africa has a complex history of ‘illegitimate’ or ‘false cures’ for HIV. It is therefore logical to anticipate that HIV cure research may face significant challenges during consent processes. HIV prevention research in South Africa has demonstrated the importance of early community engagement in educating potential research participants and promoting community acceptance of research. Consequently, in an attempt to extrapolate from this experience of engaging with communities early regarding cure research, a 15-minute educational video entitled ‘I have a dream: a world without HIV’ was developed to educate and ultimately empower potential research participants to make informed choices during consent processes in future HIV cure clinical trials. To aid others in the development of educational interventions, this paper discusses the challenges faced in developing this educational video

Inequality and ethics in paediatric HIV remission research : from Mississippi to South Africa and back

In 2013, physician-researchers announced that a baby in Mississippi had been ‘functionally cured’ of HIV [Persaud, D., Gay, H., Ziemniak, C. F., Chen, Y. H., Piatak, M., Chun, T.-W., … Luzuriaga, K. (2013b, March). Functional HIV cure after very early ART of an infected infant. Paper presented at the 20th conference on retroviruses and opportunistic infections, Atlanta, GA]. Though the child later developed a detectable viral load, the case remains unprecedented, and trials to build on the findings are planned [National Institute of Allergy and Infectious Diseases. (2014). ‘Mississippi baby’ now has detectable HIV, researchers find. Retrieved from http://www.niaid.nih.gov/news/newsreleases/2014/pages/mississippibabyhiv.aspx]. Whether addressing HIV ‘cure’ or ‘remission’, scrutiny of this case has focused largely on scientific questions, with only introductory attention to ethics. The social inequalities and gaps in care that made the discovery possible – and their ethical implications for paediatric HIV remission – have gone largely unexamined. This paper describes structural inequalities surrounding the ‘Mississippi baby’ case and a parallel case in South Africa, where proof-of-concept studies are in the early stages. We argue that an ethical programme of research into infant HIV remission ought to be ‘structurally competent’, and recommend that paediatric remission studies consider including a research component focused on social protection and barriers to care.http://www.tandfonline.com/loi/rgph202017-07-25hb2016Immunolog