scholarly journals Complexation Thermodynamics of Selenacrown Ether: Origin of High Silver(I) Selectivity of 1,5,14,18-Tetraselena-8,11,21,24-tetraoxacyclohexacosane

1999 ◽  
Vol 23 (4) ◽  
pp. 284-285
Author(s):  
Yu Liu ◽  
Shu-Ping Dong ◽  
Yoshihisa Inoue ◽  
Takehiko Wada
Keyword(s):  
Heavy Metal ◽  
Thermodynamic Parameters ◽  
Titration Calorimetry ◽  
Covalent Interaction ◽  
Heavy Metal Cations ◽  
Cation Selectivity ◽  
Thermodynamic Behaviour ◽  
First Time ◽  
High Silver ◽  
Very High

The thermodynamic parameters and relative cation selectivity for complexation of some alkali and heavy metal cations with 1,5,14,18-tetraselena-8,11,21,24-tetraoxacyclohexacosane (selena-26-crown-8) are investigated for the first time by titration calorimetry in water–acetonitrile (1:24 v/v) at 25 °C to show the contrasting complexation thermodynamic behaviour between Ag+ and alkali or Tl+ and a very high Ag+ selectivity, originating from the exclusive contribution of the enthalpy term probably owing to the partially covalent interaction between Ag+ and Se donor.

scholarly journals Shell-crossing in a ΛCDM Universe

2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn
Keyword(s):  
Dark Matter ◽  
Perturbation Theory ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Three Dimensional ◽  
Random Initial Data ◽  
Recursion Relations ◽  
Indispensable Tool ◽  
First Time ◽  
Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

scholarly journals Modeling heavy metal release in the epiphytic lichen Evernia prunastri

2021 ◽  
Author(s):  
Andrea Vannini ◽  
Luca Paoli ◽  
Riccardo Fedeli ◽  
Sharon Kwambai Kangogo ◽  
Massimo Guarnieri ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Remote Area ◽  
Metal Release ◽  
Evernia Prunastri ◽  
Epiphytic Lichen ◽  
Pollution Levels ◽  
Short Period ◽  
High Pollution ◽  
Heavy Metal Release ◽  
Very High

AbstractIn this study, the release of Cu2+ and Zn2+ was investigated and modeled in the epiphytic lichen Evernia prunastri. Samples were incubated with solutions containing these metals at ecologically relevant concentrations (10 and 100 μM) and then transplanted to a remote area and retrieved after 1, 2, 3, 6, 12, and 18 months. The results showed that, after 12 months, all samples faced similar metal reductions of ca. 80–85%, but after this period, all the involved processes seem to be no longer capable of generating further reductions. These results suggest that the lichen E. prunastri can provide information about environmental improvements after exposure to high or very high pollution levels in a relatively short period of time.

scholarly journals THERMAL EXPANSION STUDY OF A UVAROVITE RICH GARNET

2007 ◽  
Vol 21 (11) ◽  
pp. 1915-1922 ◽  
Author(s):  
G. PARTHASARTHY ◽  
R. SRINIVASAN ◽  
G. D. MUKHERJEE ◽  
C. BANSAL ◽  
ASHOK CHATTERJEE
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Thermodynamic Parameters ◽  
Semiclassical Model ◽  
Lattice Specific Heat ◽  
First Time ◽  
Thermal Expansion Study

Thermal expansion measurements have been performed on a uvarovite rich garnet sample for the first time and compared with the expansion data on grossular and pyrope-rich garnets reported in the literature. A semiclassical model has been used to analyze the data and to obtain various thermodynamic parameters. Using these parameters, the lattice specific heat and the corresponding entropy have also been calculated.

General method for cloning Neurospora crassa nuclear genes by complementation of mutants

1985 ◽  
Vol 5 (9) ◽  
pp. 2272-2278
Author(s):  
R A Akins ◽  
A M Lambowitz
Keyword(s):  
Neurospora Crassa ◽  
Genomic Library ◽  
Selection Procedure ◽  
Nuclear Genes ◽  
Shuttle Vectors ◽  
Sib Selection ◽  
First Time ◽  
Very High ◽  
Restriction Site Polymorphisms ◽  
General Method

We have developed a sib selection procedure for cloning Neurospora crassa nuclear genes by complementation of mutants. This procedure takes advantage of a modified N. crassa transformation procedure that gives as many as 10,000 to 50,000 stable transformants per microgram of DNA with recombinant plasmids containing the N. crassa qa-2+ gene. Here, we describe the use of the sib selection procedure to clone genes corresponding to auxotrophic mutants, nic-1 and inl. The identities of the putative clones were confirmed by mapping their chromosomal locations in standard genetic crosses and using restriction site polymorphisms as genetic markers. Because we can obtain very high N. crassa transformation frequencies, cloning can be accomplished with as few as five subdivisions of an N. crassa genomic library. The sib selection procedure should, for the first time, permit the cloning of any gene corresponding to an N. crassa mutant for which an appropriate selection can be devised. Analogous procedures may be applicable to other filamentous fungi before the development of operational shuttle vectors.

scholarly journals Calorimetric techniques applied to the thermodynamic study of interactions between proteins and polysaccharides

2016 ◽  
Vol 46 (8) ◽  
pp. 1491-1497
Author(s):  
Monique Barreto Santos ◽  
Bernardo de Sá Costa ◽  
Edwin Elard Garcia Rojas
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermodynamic Parameters ◽  
Isothermal Titration Calorimetry ◽  
Thermal Energy ◽  
Titration Calorimetry ◽  
Biological Macromolecules ◽  
Valuable Insight ◽  
Scanning Calorimetry ◽  
Temperature Scanning ◽  
Insight Into

ABSTRACT: The interactions between biological macromolecules have been important for biotechnology, but further understanding is needed to maximize the utility of these interactions. Calorimetric techniques provide information regarding these interactions through the thermal energy that is produced or consumed during interactions. Notable techniques include differential scanning calorimetry, which generates a thermodynamic profile from temperature scanning, and isothermal titration calorimetry that provide the thermodynamic parameters directly related to the interaction. This review described how calorimetric techniques can be used to study interactions between proteins and polysaccharides, and provided valuable insight into the thermodynamics of their interaction.

scholarly journals Visible AO Observations at Halpha for Accreting Young Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 32-33
Author(s):  
L.M. Close ◽  
K. Follette ◽  
J.R. Males ◽  
K. Morzinski ◽  
T.J. Rodigas ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Binary Stars ◽  
Optical Resolution ◽  
Ccd Camera ◽  
Short Exposure ◽  
Low Mass ◽  
Orion Trapezium ◽  
First Time ◽  
Adaptive Optics System ◽  
Very High

AbstractWe utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high-resolution science in the visible with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0.5–0.7″) we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60s) r' (0.63μm) images are slightly coarser at FWHM = 23-29 mas (Strehl ~ 28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young (~ 1 Myr) Orion Trapezium θ1 Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary θ1 Ori C1C2 was easily resolved in non-interferometric images for the first time. Relative positions of the bright trapezium binary stars were measured with ~ 0.6–5 mas accuracy. In the second commissioning run we were able to correct 378 modes and achieved good contrasts (Strehl>20% on young transition disks at Hα). We discuss the contrasts achieved at Hα and the possibility of detecting low mass (~ 1–5 Mjup) planets (past 5AU) with our new SAPPHIRES survey with MagAO at Hα.

Sign in / Sign up

Export Citation Format

Share Document