Groene keuzes voor de Nederlandse basisindustrie: Klimaatneutrale productie in een circulaire economie

Dit rapport schetst hoe de Nederlandse basisindustrie in 2050 klimaatneutraal en circulair kan produceren. Het is gebaseerd op discussies binnen het Sustainable Industry Lab vanaf medio 2021. De transitie van de basisindustrie is uitdagend, maar de ligging aan de Noordzee en het netwerk van industriële bedrijven, toeleveranciers en kennisinstellingen, maken het plausibel en wenselijk dat Nederland een flinke basisindustrie behoudt. Dat vraagt echter om keuzes, waarover de meningen uiteen lopen. We schetsen daarom ook hoe verschillende sociaal-maatschappelijke toekomstbeelden deze keuzes beïnvloeden

Five generations of nitroxyl-functionalized dendrimers

The prepn. and ESR spectroscopy of a series of fully functionalized poly(propylenimine) dendrimers (DAB-dendr-(NH2)n; n = 2, 4, 8, 16, 32, 64) with 3-carboxy-PROXYL radical end groups is described. The pendant nitroxyl end groups exhibit a strong exchange interaction. As a consequence, the ESR spectrum directly reveals the no. of end groups from the splitting between the hyperfine transitions for the lower generations. For the higher generations an increasingly exchanged-narrowed ESR spectrum is obsd. The temp. and solvent dependency of the exchange interaction is used to assess the dynamic behavior of the dendritic branches. FT-IR spectroscopy shows that a hydrogen-bonded network between the amide functionalities is present, consistent with the obsd. solvent effect on the ESR spectr

Control of Glycolysis by Glyceraldehyde-3-Phosphate Dehydrogenase in Streptococcus cremoris and Streptococcus lactis

The decreased response of the energy metabolism of lactose-starved Streptococcus cremoris upon readdition of lactose is caused by a decrease of the glycolytic activity. The decrease in glycolysis is accompanied by a decrease in the activities of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate mutase. The steady-state levels of pathway intermediates upon refeeding with lactose after various periods of starvation indicate that the decreased glycolysis is primarily due to diminished glyceraldehyde-3-phosphate dehydrogenase activity. Furthermore, quantification of the control strength exerted by glyceraldehyde-3-phosphate dehydrogenase on the overall activity of the glycolytic pathway shows that this enzyme can be significantly rate limiting in nongrowing cells.

A multi-O\u3csub\u3e2\u3c/sub\u3e complex derived from a copper(I) dendrimer

\u3cp\u3eThe high-pressure reaction of 2-vinylpyridine with the primary amines of four consecutive generations of poly(propylene imine) dendrimers (DAB-dendr- (NH\u3csub\u3e2\u3c/sub\u3e)(n)) (n = 4, 8, 16, 32) yielded dendrimers with bis[2-(2- pyridyl)ethyl]-amine (PY2) ligands. The complexation of the new dendrimers with metal ions was investigated by a variety of techniques. The reaction of the first- and fourth-generation dendrimers (n=4 and 32, respectively) with Zn(II)(ClO\u3csub\u3e4\u3c/sub\u3e)\u3csub\u3e2\u3c/sub\u3e was studied by \u3csup\u3e1\u3c/sup\u3eH NMR titration, and the complexation of all new dendrimers with Cu(II)(ClO\u3csub\u3e4\u3c/sub\u3e)\u3csub\u3e2\u3c/sub\u3e was investigated by UV/Vis and EPR spectroscopy. Quantitative coordination of one metal ion per PY2 group was demonstrated in all cases. A UV/Vis titration of the fourth-generation dendrimer DAB-dendr-(PY2)\u3csub\u3e32\u3c/sub\u3e in dichloromethane with [Cu(I)(CH\u3csub\u3e3\u3c/sub\u3eCN)\u3csub\u3e4\u3c/sub\u3e](ClO\u3csub\u3e4\u3c/sub\u3e) in acetonitrile revealed that approximately 30 Cu(I) ions were bound. Low-temperature UV/Vis spectroscopy of this complex in dichloromethane at -85°C in the presence of dioxygen showed that approximately 60-70% of the copper centers can bind dioxygen, corresponding to 10-11 of these molecules per dendrimer molecule. This complex can be considered a synthetic analogue of hemocyanin, the copper-containing oxygen transport protein from the hemolymph of molluscs and arthropods.\u3c/p\u3

Crowned dendrimers : pH-responsive pseudorotaxane formation

With the end goal of incorporating the unique structural and phys. properties of dendrimers into supramol. assemblies, bis(m-phenylene)-32-crown-10-functionalized poly(propyleneimine) dendrimers of the first and third generations have been synthesized and their interaction with paraquat diol has been investigated. Using 1H NMR, we detd. that binding to the 4 or 16 crown ether sites occurred in an anti-cooperative fashion, most likely a result of steric influences. Upon protonation of the tertiary amines in the dendritic interior, binding became independent, i.e., statistical, and the av. apparent assocn. const. increased by nearly 5-fold; this effect is attributed to rigidification of the dendrimer, which makes its binding sites more accessible and less crowded

Supramolecular polymers in action

Abstract onl

Self-assembly and guest-host properties of dendrimers

no abstrac

Siloxane polymers with quadruple hydrogen bonding units

The invention relates to the synthesis of siloxane polymers containing self-complementary quadruple hydrogen bonding groups (4H-units). The resulting polymers show unique new characteristics that result from the reversible, physical interactions between the polysiloxane chains that are based on the (supramolecular) interactions between the 4H-units. The polysiloxanes in this invention show unprecedented bulk material properties and are used as gelling agents for silicone fluids. The resulting gels are clear and display good material properties, while having unparalleled high silicone fluid contents

Pressure or flow recordings for the surveillance of hemodialysis grafts

Pressure or flow recordings for the surveillance of hemodialysis grafts. Venous pressures (VP) measured by the dialysis machine are widely used for access surveillance and have significantly improved outcomes. VP reflect the resistance in the venous outflow tract, which will rise in the presence of stenosis. Low graft flow caused by high graft resistance predicts thrombosis. In this study we investigated whether high VP coincides with low graft flow (measured by ultrasound dilution technique). Of 70 forearm bridge grafts in 42 chronic hemodialysis patients, 31 had an angiographically proven outflow stenosis. VP at 200ml/min blood flow (VP200), total graft resistance and venous outflow resistance were higher whereas graft flow was lower in patients with venous outflow tract stenosis as compared to patients without stenosis. Diagnostic power of the tests for identifying patients with venous stenosis showed no important differences. However, arterial inflow resistance, which is not reflected in VP measurements, represented a substantial and, more importantly, a highly variable percentage of total graft resistance. As a result graft flow showed no correlation with VP measurements. In conclusion, although patients with venous outflow stenosis may be identified accurately using venous pressure assessments, graft flow measurements seem to be more suitable for selecting patients at risk for thrombosis