VDAC and PorA/C1 are large diameter channels with properties reminiscent of those found in narrow channels. VDAC, located in the mitochondrial outer membrane, shows high selectivity for ATP over comparably sized ions. VDAC is described as a particular open state with anionic selectivity and multiple cation-selective closed states
tRNA Gene Structures in Bacteria
In bacteria, tRNA molecules are produced as precursors with additional nucleotides both upstream and downstream of the tRNA coding sequence. To generate a mature tRNA, the endoribonuclease RNase P removes the upstream sequence, while a number of enzymes can remove the downstream sequence. In this report, the influence of these upstream and downstream sequences for the expression of mature functional tRNA was studied
Open midplane designs based on sector coils in superconducting dipole magnets
For some cases of lattice layout in particle accelerators, the major part of the energy deposition coming from the collision is located in the midplane of the magnets. The heat produced might result in a quench in superconducting magnets. One solution for reducing the energy deposition in the coil is to introduce an opening in [...]
Sources and Occurrence of Antibiotic Resistance in the Environment
Although they have improved the health of countless numbers of humans and animals, antibiotics have been losing their effectiveness since the beginning of the antibiotic era. The use of antibiotics in raising food animals has contributed significantly to the global pool of antibiotic resistant organisms. There is no doubt that the use of antibiotics… Contents [...]
Allostery in GroEL: Its Role in the Refolding of Protein Substrates
The Escherichia coli chaperonin GroEL assists in the re-folding of misfolded substrate proteins (SPs). In response to the binding of ATP, GroEL undergoes large, allosteric structural transitions, resulting in an expansion of its central cavity and a capping of the cavity by the co-chaperonin GroES. Bound SP is released into the central cavity following the [...]
Synthesis, properties and applications of chalcogen-containing antioxidants
In the first part, the preparation and properties of chalcogen-containing vitamin E analogues are described. The sulfur compound 3,3,4,6,7-pentamethyl-2,3-dihydrobenzo[b]thiophene-5-ol was prepared by two different routes using ionic… Contents 1. INTRODUCTION 1.1 Oxygen in biological and polymeric systems 1.1.1 General introduction 1.1.2 Mechanism of autoxidation 1.1.3 Endogenous defense systems 1.1.4 Oxidative degradation and stabilization of polymers [...]
Causes of Substitution Frequency Variation in Pathogenic Bacteria
Estimating substitution frequencies at sites that influence (Ka) and do not influence (Ks) the amino acid sequence is important for understanding the dynamics of molecular sequence evolution and the selective pressures that have shaped genetic variation.The aim of this work was to gain a deeper understanding of the driving forces of substitution frequency variation in [...]
Infaunal Effects on Permeable Sediment Processes
The role of infauna on permeable sediment processes is poorly understood due to methodological limitations and a lack of empirical data. The interactions among porewater flows, sediments, and biogenic structures present a physically and … Contents Chapter 1: Executive Summary: Infaunal Effects on Permeable Sediment Processes Chapter 2: Macrofaunal modification of porewater advection: The role [...]
Field Theories and Vortices with Nontrivial Geometry
This thesis investigates aspects of field theories and soliton solutions with nontrivial topology. In particular we explore the following effective models: a limited sector of the scalar Electroweak theory called extended Abelian Higgs model, and a classical mechanics model derived from the low energy SU(2) Yang-Mills theory.The extended Abelian Higgs model applied on two-component plasma [...]
Energy Transfer and Conversion in the Magnetosphere-Ionosphere System
Magnetized planets, such as Earth, are strongly influenced by the solar wind. The Sun is very dynamic, releasing varying amounts of energy, resulting in a fluctuating energy and momentum exchange between the solar wind and planetary magnetospheres. The efficiency of this coupling is thought to be controlled by magnetic reconnection occurring at the boundary between [...]