A model for assessing the impact of electronic procurement forms

This paper aims to contribute to the development of a model for assessing the direct and indirect impact of various forms of electronic procurement (EP) on a firm¿s integral purchasing (-related) costs. The model builds on existing classifications of purchasing costs and benefits and is illustrated by means of a number of empirical cases

Engineering vascularised tissues in vitro

Tissue engineering aims at replacing or regenerating tissues lost due to diseases or traumas (Langer and Vacanti, 1993). However, mimicking in vitro the physiological complexity of vascularized tissue is a major obstacle, which possibly contributes to impaired healing in vivo. In higher organisms, native features including the vascular network, the lymphatic networks and interstitial flow promote both mass transport and organ development. Attempts to mimic those features in engineered tissues will lead to more clinically relevant cell-based therapies. Aside from current strategies promoting angiogenesis from the host, an alternative concept termed prevascularization is emerging. It aims at creating a biological vasculature inside an engineered tissue prior to implantation. This vasculature can rapidly anastamose with the host and enhances tissue survival and differentiation. Interestingly, growing evidence supports a role of the vasculature in regulating pattern formation and tissue differentiation. Thus, prevascularized tissues also benefit from an intrinsic contribution of their vascular system to their development. From those early attempts are emerging a body of principles and strategies to grow and maintain, in vitro, those self-assembled biological vascular networks. This could lead to the generation of engineered tissues of more physiologically relevant complexity and improved regenerative potential

General covariance of the non-abelian DBI-action: Checks and Balances

We perform three tests on our proposal to implement diffeomorphism invariance in the non-abelian D0-brane DBI action as a basepoint independence constraint between matrix Riemann normal coordinate systems. First we show that T-duality along an isometry correctly interchanges the potential and kinetic terms in the action. Second, we show that the method to impose basepoint independence using an auxiliary dN^2-dimensional non-linear sigma model also works for metrics which are curved along the brane, provided a physical gauge choice is made at the end. Third, we show that without alteration this method is applicable to higher order in velocities. Testing specifically to order four, we elucidate the range of validity of the symmetrized trace approximation to the non-abelian DBI action.Comment: LaTeX, 22 page

How Will English Higher Education Look Like in 2025?

In light of the recent higher education policy changes in the UK, a scenario study was carried out – based on the Delphi-method – exploring the longer term impact (2025) of the policies on English higher education. The two scenarios are briefly presented below

Gezonde spanning : beleidsevaluatie van de MUB : eindrapport

This is a pre-print version of the book Gezonde spanning: beleidsevaluatie van de MUB: eindrapport, published by Center for Higher Education Policy Studies (CHEPS), Universiteit Twente. This version is reproduced with the permission of Center for Higher Education Policy Studies (CHEPS). http://doc.utwente.nl/view/research_institute/Center_for_Higher_Education_Policy_Studies_=28CHEPS=29.htmlAan het Center for Higher Education Policy Studies (CHEPS) van de Universiteit Twente is door het ministerie van Onderwijs, Cultuur en Wetenschap de opdracht verleend een evaluatiestudie uit te voeren naar de Modernisering Universitaire Bestuursorganisatie (MUB). Deze studie is uitgevoerd in de periode juni 2004 – juni 2005

Pancreatic beta cell autophagy is impaired in type 1 diabetes

Aims/hypothesis Pancreatic beta cells are subjected to exogenous damaging factors such as proinflammatory cytokines or excess glucose that can cause accumulation of damage-inducing reactive oxygen species during the pathogenesis of diabetes. We and others have shown that beta cell autophagy can reduce reactive oxygen species to protect against apoptosis. While impaired islet autophagy has been demonstrated in human type 2 diabetes, it is unknown if islet autophagy is perturbed in the pathogenesis of type 1 diabetes. We hypothesised that beta cell autophagy is dysfunctional in type 1 diabetes, and that there is a progressive loss during early diabetes development. Methods Pancreases were collected from chloroquine-injected and non-injected non-obese diabetes-resistant (NOR) and non-obese diabetic (NOD) mice. Age- and BMI-matched pancreas tissue sections from human organ donors (N = 34) were obtained from the Network for Pancreatic Organ Donors with Diabetes (nPOD). Tissue sections were stained with antibodies against proinsulin or insulin (beta cell markers), microtubule-associated protein 1 light chain 3 A/B (LC3A/B; autophagosome marker), lysosomal-associated membrane protein 1 (LAMP1; lysosome marker) and p62 (autophagy adaptor). Images collected on a scanning laser confocal microscope were analysed with CellProfiler and ImageJ. Secondary lysosomes and telolysosomes were assessed in electron micrographs of human pancreatic tissue sections (n = 12), and energy dispersive x-ray analysis was performed to assess distribution of elements (n = 5). Results We observed increased autophagosome numbers in islets of diabetic NOD mice (p = 0.008) and increased p62 in islets of both non-diabetic and diabetic NOD mice (p < 0.001) vs NOR mice. There was also a reduction in LC3-LAMP1 colocalisation in islets of diabetic NOD mice compared with both non-diabetic NOD (p < 0.001) and NOR mice (p < 0.001). Chloroquine elicited accumulation of autophagosomes in the islets of NOR (p = 0.003) and non-diabetic NOD mice (p < 0.001), but not in islets of diabetic NOD mice; and stimulated accumulation of p62 in NOR (p < 0.001), but not in NOD mice. We observed reduced LC3-LAMP1 colocalisation (p < 0.001) in residual beta cells of human donors with type 1 diabetes vs non-diabetic participants. We also observed reduced colocalisation of proinsulin with LAMP1 in donors with type 1 diabetes (p < 0.001). Electron microscopy also revealed accumulation of telolysosomes with nitrogen-dense rings in beta cells of autoantibody-positive donors (p = 0.002). Conclusions/interpretation We provide evidence of islet macroautophagy/crinophagy impairment in human type 1 diabetes. We also document accumulation of telolysosomes with peripheral nitrogen in beta cells of autoantibody-positive donors, demonstrating altered lysosome content that may be associated with lysosome dysfunction before clinical hyperglycaemia. Similar macroautophagy impairments are present in the NOD mouse model of type 1 diabetes

Modular ATR FT-IR microreactor chip for optimizing reaction conditions

A silicon chip for attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy in combination with a modular PDMS herringbone mixer and a microreactor has been successfully fabricated and tested. The modular design allows the chip to be used for a variety of reactions. A model synthesis of 1-butyl-2,5-dimethyl-1H-pyrrole from hexane-2,5-dione with 1-butylamine has been performed on chip. When plotting the natural logarithm of the peak area corresponding to the ketone stretch vibration at 1710cm-1, against the residence time, a linear curve can be fitted, suggesting this step to be a first order reaction

Modular ATR FT-IR microreactor chip for optimizing reaction conditions

A silicon chip for attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy in combination with a modular PDMS herringbone mixer and a microreactor has been successfully fabricated and tested. The modular design allows the chip to be used for a variety of reactions. A model synthesis of 1-butyl-2,5-dimethyl-1H-pyrrole from hexane-2,5-dione with 1-butylamine has been performed on chip. When plotting the natural logarithm of the peak area corresponding to the ketone stretch vibration at 1710cm-1, against the residence time, a linear curve can be fitted, suggesting this step to be a first order reaction