University of Nebraska–Lincoln

About: University of Nebraska–Lincoln is a education organization based out in Lincoln, Nebraska, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 28059 authors who have published 61544 publications receiving 2139104 citations. The organization is also known as: Nebraska & UNL.

Function of c-mos proto-oncogene product in meiotic maturation in Xenopus oocytes

Abstract: The c-mos proto-oncogene is expressed as a maternal mRNA in oocytes and early embryos of Xenopus laevis, but its translation product pp39mos is detectable only during progesterone-induced oocyte maturation. Microinjection of mos-specific antisense oligonucleotides into oocytes not only prevents expression ofpp39mos, but also blocks germinal vesicle breakdown, indicating that it functions during reinitiation of meiotic division.

Strained hybrid perovskite thin films and their impact on the intrinsic stability of perovskite solar cells.

Abstract: Organic-inorganic hybrid perovskite (OIHP) solar cells have achieved comparable efficiencies to those of commercial solar cells, although their instability hinders their commercialization. Although encapsulation techniques have been developed to protect OIHP solar cells from external stimuli such as moisture, oxygen, and ultraviolet light, understanding of the origin of the intrinsic instability of perovskite films is needed to improve their stability. We show that the OIHP films fabricated by existing methods are strained and that strain is caused by mismatched thermal expansion of perovskite films and substrates during the thermal annealing process. The polycrystalline films have compressive strain in the out-of-plane direction and in-plane tensile strain. The strain accelerates degradation of perovskite films under illumination, which can be explained by increased ion migration in strained OIHP films. This study points out an avenue to enhance the intrinsic stability of perovskite films and solar cells by reducing residual strain in perovskite films.

Cobalt oxide surface chemistry: The interaction of CoO(1 0 0), Co3O4(1 1 0) and Co3O4(1 1 1) with oxygen and water

Abstract: Cobalt oxides comprise two readily accessible cation oxidation states: Co 2+ and Co 3+ , which are thermodynamically competitive under common ambient conditions, and redox mechanisms connecting the two states are largely responsible for their success in partial oxidation catalysis. In our studies, CoO(1 0 0), Co 3 O 4 (1 1 0), and Co 3 O 4 (1 1 1) single crystal substrates have been investigated with X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), and low energy electron diffraction (LEED) for their surface reactivity toward O 2 and H 2 O and for their stability under reducing UHV conditions. There is facile inter-conversion between CoO and Co 3 O 4 stoichiometry at the oxide surface which, despite the compositional variability, remains well ordered in long-range structure. Surface impurities, however, can pin the surface at either CoO or Co 3 O 4 compositional extremes. Contrary to reports of a pressure gap that creates difficulty in oxide hydroxylation under UHV, it is pos sible to hydroxylate both cobalt monoxide and spinel oxide substrates with H 2 O, provided sufficient activation is available to dis sociate the water molecule.

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

Abstract: The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta)<2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.