Utrecht University

About: Utrecht University is a education organization based out in Utrecht, Utrecht, Netherlands. It is known for research contribution in the topics: Population & Poison control. The organization has 58176 authors who have published 139351 publications receiving 6214282 citations. The organization is also known as: UU & Universiteit Utrecht.

Direct control of the Forkhead transcription factor AFX by protein kinase B

Abstract: The phosphatidylinositol-3-OH-kinase (PI(3)K) effector protein kinase B (refs 1, 2) regulates certain insulin-responsive genes3,4, but the transcription factors regulated by protein kinase B have yet to be identified. Genetic analysis in Caenorhabditis elegans has shown that the Forkhead transcription factor daf -16 is regulated by a pathway consisting of insulin-receptor-like daf- 2 and PI(3)K-like age -1 (5–8). Here we show that protein kinase B phosphorylates AFX, a human orthologue of daf -16 (refs 5, 6, 9), both in vitro and in vivo. Inhibition of endogenous PI(3)K and protein kinase B activity prevents protein kinase B-dependent phosphorylation of AFX and reveals residual protein kinase B-independent phosphorylation that requires Ras signalling towards the Ral GTPase. In addition, phosphorylation of AFX by protein kinase B inhibits its transcriptional activity. Together, these results delineate a pathway for PI(3)K-dependent signalling to the nucleus.

The contribution of biomass in the future global energy supply: a review of 17 studies

Abstract: This paper discusses the contribution of biomass in the future global energy supply. The discussion is based on a review of 17 earlier studies on the subject. These studies have arrived at widely different conclusions about the possible contribution of biomass in the future global energy supply (e.g., from below 100 EJ yr-1 to above 400 EJ yr-1 in 2050). The major reason for the differences is that the two most crucial parameters - land availability and yield levels in energy crop production - are very uncertain, and subject to widely different opinions (e.g., the assessed 2050 plantation supply ranges from below 50 EJ yr-1 to almost 240 EJ yr-1). However, also the expectations about future availability of forest wood and of residues from agriculture and forestry vary substantially among the studies. The question how an expanding bioenergy sector would interact with other land uses, such as food production, biodiversity, soil and nature conservation, and carbon sequestration has been insufficiently analyzed in the studies. It is therefore difficult to establish to what extent bioenergy is an attractive option for climate change mitigation in the energy sector. A refined modeling of interactions between different uses and bioenergy, food and materials production - i.e., of competition for resources, and of synergies between different uses - would facilitate an improved understanding of the prospects for large-scale bioenergy and of future land-use and biomass management in general. © 2003 Elsevier Science Ltd. All rights reserved.

An intensity evaluation method: EVAL-14

Abstract: A reflection intensity integration method is presented based upon ab initio calculation of three-dimensional (x, y, ω) reflection boundaries from a few physical crystal and instrument parameters. It is especially useful in challenging circumstances, such as the case of a crystal that is far from spherical, anisotropic mosaicity, α1α2 peak splitting, interference from close neighbours, twin lattices or satellite reflections, and the case of streaks from modulated structures, all of which may frustrate the customary profile-learning and -fitting procedures. The method, called EVAL-14, has been implemented and extensively tested on a Bruker Nonius KappaCCD diffractometer.

A mutation in the RET proto-oncogene associated with multiple endocrine neoplasia type 2B and sporadic medullary thyroid carcinoma

Abstract: Multiple endocrine neoplasia type 2 (MEN 2) comprises three clinically distinct, dominantly inherited cancer syndromes. MEN 2A patients develop medullary thyroid carcinoma (MTC) and phaeochromocytoma. MEN 2B patients show in addition ganglioneuromas of the gastrointestinal tract and skeletal abnormalities. In familial MTC, only the thyroid is affected. Germ-line mutations of the RET proto-oncogene have recently been reported in association with MEN 2A and familial MTC. All mutations occurred within codons specifying cysteine residues in the transition point between the RET protein extracellular and transmembrane domains. We now show that MEN 2B is also associated with mutation of the RET proto-oncogene. A mutation in codon 664, causing the substitution of a threonine for a methionine in the tyrosine kinase domain of the protein, was found in all nine unrelated MEN 2B patients studied. The same mutation was found in six out of 18 sporadic tumours.

Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise

Abstract: [1] Ice sheet mass balance estimates have improved substantially in recent years using a variety of techniques, over different time periods, and at various levels of spatial detail. Considerable disparity remains between these estimates due to the inherent uncertainties of each method, the lack of detailed comparison between independent estimates, and the effect of temporal modulations in ice sheet surface mass balance. Here, we present a consistent record of mass balance for the Greenland and Antarctic ice sheets over the past two decades, validated by the comparison of two independent techniques over the last 8 years: one differencing perimeter loss from net accumulation, and one using a dense time series of time-variable gravity. We find excellent agreement between the two techniques for absolute mass loss and acceleration of mass loss. In 2006, the Greenland and Antarctic ice sheets experienced a combined mass loss of 475 ± 158 Gt/yr, equivalent to 1.3 ± 0.4 mm/yr sea level rise. Notably, the acceleration in ice sheet loss over the last 18 years was 21.9 ± 1 Gt/yr2 for Greenland and 14.5 ± 2 Gt/yr2 for Antarctica, for a combined total of 36.3 ± 2 Gt/yr2. This acceleration is 3 times larger than for mountain glaciers and ice caps (12 ± 6 Gt/yr2). If this trend continues, ice sheets will be the dominant contributor to sea level rise in the 21st century.