Uppsala University

About: Uppsala University is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Gene. The organization has 36485 authors who have published 107509 publications receiving 4220668 citations. The organization is also known as: Uppsala universitet & uu.se.

Water Determines the Structure and Dynamics of Proteins

Abstract: Water is an essential participant in the stability, structure, dynamics, and function of proteins and other biomolecules. Thermodynamically, changes in the aqueous environment affect the stability of biomolecules. Structurally, water participates chemically in the catalytic function of proteins and nucleic acids and physically in the collapse of the protein chain during folding through hydrophobic collapse and mediates binding through the hydrogen bond in complex formation. Water is a partner that slaves the dynamics of proteins, and water interaction with proteins affect their dynamics. Here we provide a review of the experimental and computational advances over the past decade in understanding the role of water in the dynamics, structure, and function of proteins. We focus on the combination of X-ray and neutron crystallography, NMR, terahertz spectroscopy, mass spectroscopy, thermodynamics, and computer simulations to reveal how water assist proteins in their function. The recent advances in computer s...

Exploration of the compositional space for mixed lead halogen perovskites for high efficiency solar cells

Abstract: Lead halide perovskites have attracted considerable interest as photoabsorbers in PV-applications over the last few years. The most studied perovskite material achieving high photovoltaic performance has been methyl ammonium lead iodide, CH3NH3PbI3. Recently the highest solar cell efficiencies have, however, been achieved with mixed perovskites where iodide and methyl ammonium partially have been replaced by bromide and formamidinium. In this work, the mixed perovskites were explored in a systematic way by manufacturing devices where both iodide and methyl ammonium were gradually replaced by bromide and formamidinium. The absorption and the emission behavior as well as the crystallographic properties were explored for the perovskites in this compositional space. The band gaps as well as the crystallographic structures were extracted. Small changes in the composition of the perovskite were found to have a large impact on the properties of the materials and the device performance. In the investigated compositional space, cell efficiencies, for example, vary from a few percent up to 20.7%. From the perspective of applications, exchanging iodide with bromide is especially interesting as it allows tuning of the band gap from 1.5 to 2.3 eV. This is highly beneficial for tandem applications, and an empirical expression for the band gap as a function of composition was determined. Exchanging a small amount of iodide with bromide is found to be highly beneficial, whereas a larger amount of bromide in the perovskite was found to cause intense sub band gap photoemission with detrimental results for the device performance. This could be caused by the formation of a small amount of an iodide rich phase with a lower band gap, even though such a phase was not observed in diffraction experiments. This shows that stabilizing the mixed perovskites will be an important task in order to get the bromide rich perovskites, which has a higher band gap, to reach the same high performance obtained with the best compositions.

Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture

Abstract: Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups.