Post Millennium Tension

In order to understand the world we live in, as it is mediated through technology, this process driven artwork Post Millennium Tension uses a machine I created specifically to visualize the inner workings of contemporary technology. The artwork is a large multi-paneled photograph and light-box display, that depicts the intimate everyday moments within a relationship. The relationship seen in the photographs is one that began on a phone where the individuals were matched by the Tinder algorithm. That relationship is documented and archived on a phone. The images act as proof and the artwork as a monument to a relationship mediated through technology. To address this, or to explain it visually, I developed a system that creates images that reflect the digital origin of the image while photographing the machine to show the scale of data. How we use devices that create images that supersede our vision or ability to see, is explored

Mutual A domain interactions in the force sensing protein von Willebrand factor

The von Willebrand factor (VWF) is a glycoprotein in the blood that plays a central role in hemostasis. Among other functions, VWF is responsible for platelet adhesion at sites of injury via its A1 domain. Its adjacent VWF domain A2 exposes a cleavage site under shear to degrade long VWF fibers in order to prevent thrombosis. Recently, it has been shown that VWF A1/A2 interactions inhibit the binding of platelets to VWF domain A1 in a force-dependent manner prior to A2 cleavage. However, whether and how this interaction also takes place in longer VWF fragments as well as the strength of this interaction in the light of typical elongation forces imposed by the shear flow of blood remained elusive. Here, we addressed these questions by using single molecule force spectroscopy (SMFS), Brownian dynamics (BD), and molecular dynamics (MD) simulations. Our SMFS measurements demonstrate that the A2 domain has the ability to bind not only to single A1 domains but also to VWF A1A2 fragments. SMFS experiments of a mutant [A2] domain, containing a disulfide bond which stabilizes the domain against unfolding, enhanced A1 binding. This observation suggests that the mutant adopts a more stable conformation for binding to A1. We found intermolecular A1/A2 interactions to be preferred over intramolecular A1/A2 interactions. Our data are also consistent with the existence of two cooperatively acting binding sites for A2 in the A1 domain. Our SMFS measurements revealed a slip-bond behavior for the A1/A2 interaction and their lifetimes were estimated for forces acting on VWF multimers at physiological shear rates using BD simulations. Complementary fitting of AFM rupture forces in the MD simulation range adequately reproduced the force response of the A1/A2 complex spanning a wide range of loading rates. In conclusion, we here characterized the auto-inhibitory mechanism of the intramolecular A1/A2 bond as a shear dependent safeguard of VWF, which prevents the interaction of VWF with platelets

Monitoring and evaluation in global HIV/AIDS control - weighing incentives and disincentives for coordination among global and local actors

This paper discusses coordination efforts of both donors and recipient countries in the monitoring and evaluation (M&E) of health outcomes in the field of HIV/AIDS. The coordination of M&E is a much underdeveloped area in HIV/AIDS programming in which, however, important first steps towards better synchronisation have already been taken. In this paper, we review the concepts and meanings commonly applied to M&E, and approaches and strategies for better coordination of M&E in the field of HIV/AIDS. Most importantly, drawing on this analysis, we examine why the present structure of global health governance in this area is not creating strong enough incentives for effective coordination among global and local actors. Copyright © 2010 John Wiley & Sons, Ltd

Victims or villains? deconstructing the policing of migrant children in South African border towns

ABSTRACT Research surrounding issues of police treatment of migrant children at South Africa’s border areas remains incomplete and often policy-driven. Similarly, theoretical literature on policing often fails to consider the sociological and anthropological complexities that impact upon police officers’ conceptions of criminality, vulnerability, and ultimately, their behaviour. This paper seeks to study the policing of migrant children in a predominantly sociological framework by examining the influences on South African Police Service (SAPS) officers’ behaviour and constructions of criminality and vulnerability in migrant children. The research is grounded within an extensive review of the theoretical and contemporary literature pertaining to policing, policing of vulnerable groups, and the South African policing context, and included approximately three months of ethnographic fieldwork of interviews and participant observation in Nkomazi Municipality at South Africa’s border with Mozambique. Conclusions identified that personal history and experiences, an officer’s perceptions of his or her work within a localized and even nationalized environment of some accountability and culture, as well as external factors ought to be heavily considered and are fluid influences on a police officer’s behaviour toward migrant children. These factors, which can result in seemingly arbitrary policing within a nonetheless structured localized and individualized culture, suggest a unique framework within which to consider policing from a sociological perspective even beyond their specific impact on migrant children or the border area

Multiplexed protein force spectroscopy reveals equilibrium protein folding dynamics and the low-force response of von Willebrand factor

Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force regulation, and function. So far, the field has relied primarily on atomic force microscope and optical tweezers assays that, while powerful, are limited in force resolution, throughput, and require feedback for constant force measurements. Here, we present a modular approach based on magnetic tweezers (MT) for highly multiplexed protein force spectroscopy. Our approach uses elastin-like polypeptide linkers for the specific attachment of proteins, requiring only short peptide tags on the protein of interest. The assay extends protein force spectroscopy into the low force (<1 pN) regime and enables parallel and ultra-stable measurements at constant forces. We present unfolding and refolding data for the small, single-domain protein ddFLN4, commonly used as a molecular fingerprint in force spectroscopy, and for the large, multidomain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. For both proteins, our measurements reveal exponential force dependencies of unfolding and refolding rates. We directly resolve the stabilization of the VWF A2 domain by Ca2+ and discover transitions in the VWF C domain stem at low forces that likely constitute the first steps of VWF’s mechano-activation. Probing the force-dependent lifetime of biotin–streptavidin bonds, we find that monovalent streptavidin constructs with specific attachment geometry are significantly more force stable than commercial, multivalent streptavidin. We expect our modular approach to enable multiplexed force-spectroscopy measurements for a wide range of proteins, in particular in the physiologically relevant low-force regime

Human Transplant Kidneys on Normothermic Machine Perfusion Display Endocrine Activity

Background. Normothermic machine perfusion (NMP) is an alternative to hypothermic machine perfusion (HMP) for donor kidney preservation before transplantation. Contrary to HMP, NMP allows for functional assessment of donor kidneys because normothermic conditions allow for metabolic activity. The kidneys are key producers of hormones. Yet, it remains unknown whether donor kidneys during NMP display endocrine functions. Methods. Fifteen donor kidneys were subjected to HMP followed by 2 h of NMP before transplantation. NMP perfusate was collected at 3 time points (0, 1, 2 h) for the measurements of prorenin/renin, erythropoietin (EPO), and vitamin D, and urine samples were collected at 1 h and 2 h for urodilatin measurement. Fifteen HMP perfusate samples were collected for the same measurements. Results. Kidneys on NMP secreted significantly more prorenin, renin, EPO, and active vitamin D than during HMP. EPO and vitamin D secretion remained stable during 2 h of NMP, whereas the prorenin release rate increased and renin release rate decreased after 1 h. Donation after brain death kidneys secreted more vitamin D and less EPO during NMP than donation after circulatory death kidneys. Twelve donor kidneys produced urine during NMP and released detectable levels of urodilatin. Kidneys exhibited a large variation in hormone release rates. No significant differences were found in hormone release capacity between delayed graft function (DGF) and non-DGF kidneys, and no significant correlations were found between hormone release rates and the duration of DGF or 1-mo posttransplant serum creatinine levels. Conclusions. Human transplant kidneys display endocrine activity during NMP. To explore whether correlations exist between hormone release rates and posttransplant kidney function, large numbers of kidneys are required.</p