Fatty acid synthesis in Escherichia coli and its applications towards the production of fatty acid based biofuels

The idea of renewable and regenerative resources has inspired research for more than a hundred years. Ideally, the only spent energy will replenish itself, like plant material, sunlight, thermal energy or wind. Biodiesel or ethanol are examples, since their production relies mainly on plant material. However, it has become apparent that crop derived biofuels will not be sufficient to satisfy future energy demands. Thus, especially in the last decade a lot of research has focused on the production of next generation biofuels. A major subject of these investigations has been the microbial fatty acid biosynthesis with the aim to produce fatty acids or derivatives for substitution of diesel. As an industrially important organism and with the best studied microbial fatty acid biosynthesis, Escherichia coli has been chosen as producer in many of these studies and several reviews have been published in the fields of E. coli fatty acid biosynthesis or biofuels. However, most reviews discuss only one of these topics in detail, despite the fact, that a profound understanding of the involved enzymes and their regulation is necessary for efficient genetic engineering of the entire pathway. The first part of this review aims at summarizing the knowledge about fatty acid biosynthesis of E. coli and its regulation, and it provides the connection towards the production of fatty acids and related biofuels. The second part gives an overview about the achievements by genetic engineering of the fatty acid biosynthesis towards the production of next generation biofuels. Finally, the actual importance and potential of fatty acid-based biofuels will be discussed

Applicants reactions to selection procedures : prediction uncertainty as a moderator of the relationship between procedural fairness and organizational attractiveness

Prozedurale Fairnessbewertungen beeinflussen in starkem Maße Einstellungen und das Verhalten von Personen gegenüber Organisationen. Dies gilt auch für die Bewertung von Personalauswahlverfahren. Personen, die ein Auswahlverfahren als fair einschätzen, bewerten die betreffende Organisation auch als attraktiveren Arbeitgeber. Die vorliegende Studie untersuchte, in wieweit dispositionale Vorhersageunsicherheit auf Seiten der Bewerbenden diesen Zusammenhang verstärkt. Die Ergebnisse der Studie demonstrieren in Abhängigkeit von der Auswahlentscheidung unterschiedliche moderierende Einflüsse von Vorhersageunsicherheit auf den Zusammenhang zwischen prozeduraler Fairnessbewertung und organisationaler Attraktivität. Implikationen für die Forschung zum Einfluss von Fairnessbewertungen sowie für die Anwendung im organisationalen Kontext werden diskutiert

Applicants’ reactions to selection procedures – Prediction uncertainty as a moderator of the relationship between procedural fairness and organizational attractiveness

Procedural fairness judgments strongly influence peoples’ attitudes and behaviors towards organizations. This is also true for the evaluation of selection systems. People who perceive a selection procedure as fairer judge the respective organization as a more attractive employer. The present study examined whether this relationship is strengthened by applicants’ prediction uncertainty. Results demonstrate a differential moderating effect of prediction uncertainty on the relationship between procedural fairness judgments and organizational attractiveness, depending on the outcome of the application. Implications for research on fairness judgments as well as applications in organizational settings are discussed.

Multifractality of wavefunctions at the quantum Hall transition revisited

We investigate numerically the statistics of wavefunction amplitudes $\psi({\bf r})$ at the integer quantum Hall transition. It is demonstrated that in the limit of a large system size the distribution function of $|\psi|^2$ is log-normal, so that the multifractal spectrum $f(\alpha)$ is exactly parabolic. Our findings lend strong support to a recent conjecture for a critical theory of the quantum Hall transition.Comment: 4 pages Late

Multifractal properties of critical eigenstates in two-dimensional systems with symplectic symmetry

The multifractal properties of electronic eigenstates at the metal-insulator transition of a two-dimensional disordered tight-binding model with spin-orbit interaction are investigated numerically. The correlation dimensions of the spectral measure $\widetilde{D}_{2}$ and of the fractal eigenstate $D_{2}$ are calculated and shown to be related by $D_{2}=2\widetilde{D}_{2}$. The exponent $\eta=0.35\pm 0.05$ describing the energy correlations of the critical eigenstates is found to satisfy the relation $\eta=2-D_{2}$.Comment: 6 pages RevTeX; 3 uuencoded, gzipped ps-figures to appear in J. Phys. Condensed Matte

Optimization of macroelement concentrations, pH and osmolarity for triacylglycerol accumulation in Rhodococcus opacus strain PD630

The refinement of biodiesel or renewable diesel from bacterial lipids has a great potential to make a contribution for energy production in the future. This study provides new data concerning suitable nutrient concentrations for cultivation of the Gram-positive Rhodococcus opacus PD630, which is able to accumulate large amounts of lipids during nitrogen limitation. Enhanced concentrations of magnesium have been shown to increase the final optical density and the lipid content of the cells. Elevated phosphate concentrations slowed down the onset of the accumulation phase, without a clear effect on the final optical density and the cell’s lipid content. A robust growth of R. opacus was possible in the presence of ammonium concentrations of up to 1.4 g l-1 and sucrose concentrations of up to 240 g l-1, with an optimum regarding growth and lipid storage observed in the range of 0.2 to 0.4 g l-1 ammonium and 20 to 40 g l-1 sucrose, respectively. Moreover, R. opacus showed tolerance to high salt concentrations

The costs of non-training in chronic wounds : estimates through practice simulation

The high prevalence and incidence rates of chronic wounds represent high financial costs for patients, families, health services, and for society in general. Therefore, the proper training of health professionals engaged in the diagnosis and treatment of these wounds can have a very positive impact on the reduction of costs. As technology advances rapidly, the knowledge acquired at school soon becomes outdated, and only through lifelong learning can skills be constantly updated. Information and Communication Technologies play a decisive role in this field. We have prepared a cost estimate model of Non-Training, using a Simulator (Web Based System – e-fer) for the diagnosis and treatment of chronic wounds. The preliminary results show that the costs involved in the diagnosis and treatment of chronic wounds are markedly higher in health professionals with less specialized training

In Situ Pore Formation in Graphite Through Solvent Co-Intercalation: A New Model for The Formation of Ternary Graphite Intercalation Compounds Bridging Batteries and Supercapacitors

For Li‐ion and Na‐ion batteries, the intercalation behavior of graphite anodes is quite different. While Li‐ions intercalate, Na‐ions only co‐intercalate with solvent molecules from the electrolyte solution leading to ternary graphite intercalation compound (t‐GIC) formation along with an expansion of the graphite interlayer spacing to 1.2 nm. This large interlayer spacing represents a micropore with parallel slit geometry. Little is known about t‐GIC formation, but it is commonly believed that throughout the reaction the ion is accompanied by either a full or partial solvation shell. Here, it is elucidated for the first time, using two independent methods – mass measurements and electrochemical impedance spectroscopy – supplemented by operando microscopy, entropymetry and simulations, that the storage mechanism is far more complex. A new model for the electrochemical solvent co‐intercalation process is proposed: As soon as solvated ions enter, the graphite structure is flooded with free solvents, which are subsequently replaced by solvated ions. Close to full sodiation, few free solvents remain and structural rearrangement take place to reach the full storage capacity. Thus, t‐GICs represent a unique case of switchable microporous systems and hence appear as a bridge between ion storage in the bulk phase and in micropores, i.e., between batteries and supercapacitors.Peer Reviewe

Circulation Statistics in Three-Dimensional Turbulent Flows

We study the large $\lambda$ limit of the loop-dependent characteristic functional $Z(\lambda)=$, related to the probability density function (PDF) of the circulation around a closed contour $c$. The analysis is carried out in the framework of the Martin-Siggia-Rose field theory formulation of the turbulence problem, by means of the saddle-point technique. Axisymmetric instantons, labelled by the component $\sigma_{zz}$ of the strain field -- a partially annealed variable in our formalism -- are obtained for a circular loop in the $xy$ plane, with radius defined in the inertial range. Fluctuations of the velocity field around the saddle-point solutions are relevant, leading to the lorentzian asymptotic behavior $Z(\lambda) \sim 1/{\lambda^2}$. The ${\cal O}(1 / {\lambda^4})$ subleading correction and the asymmetry between right and left PDF tails due to parity breaking mechanisms are also investigated.Comment: Computations are discussed in a more detailed way; accepted for publication in Physical Review