Studies on Bacterial Growth and Arsenic (III) Biosorption Using Bacillussubtilis

Gram-negative bacteria Bacillus subtilis biosorps arsenic (III) ion from its aqueous solution. The maximum biosorption of lead is w = 97.30 · 10–2 within 72 h of inoculation time with optimum pH 3.5 and optimum temperature 40 °C for w = 500 · 10–6 initial loading of arsenic ion in a shake flask (optimum n = 60 min–1). 7 days old and = 30 · 10–2 inoculum culture is used in the studies. Arsenic (III) ion is measured by using atomic absorption spectrophotometer into an air-acetylene flame and absorbance is measured at 229 nm. The maximum bacterial growth is noticed as c = 3.90 · 108 cells mL–1 at optimum conditions. The bacteria can tolerate upto w = 600 · 10–6 of initial arsenic (III) ion loading. The Langmuir and Freundlich Isotherms fit the biosorption data reasonably well and played a major role in giving a better understanding of bioprocess modeling. The Monod Model for bacterial growth shows that the specific growth rate () of B. subtilis in the initial w = 500 · 10–6 of arsenic (III) ion loading, is found to be 0.017 s –

Studies on Bacterial Growth and Arsenic (III) Biosorption Using Bacillussubtilis

Gram-negative bacteria Bacillus subtilis biosorps arsenic (III) ion from its aqueous solution. The maximum biosorption of lead is w = 97.30 · 10–2 within 72 h of inoculation time with optimum pH 3.5 and optimum temperature 40 °C for w = 500 · 10–6 initial loading of arsenic ion in a shake flask (optimum n = 60 min–1). 7 days old and = 30 · 10–2 inoculum culture is used in the studies. Arsenic (III) ion is measured by using atomic absorption spectrophotometer into an air-acetylene flame and absorbance is measured at 229 nm. The maximum bacterial growth is noticed as c = 3.90 · 108 cells mL–1 at optimum conditions. The bacteria can tolerate upto w = 600 · 10–6 of initial arsenic (III) ion loading. The Langmuir and Freundlich Isotherms fit the biosorption data reasonably well and played a major role in giving a better understanding of bioprocess modeling. The Monod Model for bacterial growth shows that the specific growth rate () of B. subtilis in the initial w = 500 · 10–6 of arsenic (III) ion loading, is found to be 0.017 s –

Energy decay for the damped wave equation under a pressure condition

We establish the presence of a spectral gap near the real axis for the damped wave equation on a manifold with negative curvature. This results holds under a dynamical condition expressed by the negativity of a topological pressure with respect to the geodesic flow. As an application, we show an exponential decay of the energy for all initial data sufficiently regular. This decay is governed by the imaginary part of a finite number of eigenvalues close to the real axis.Comment: 32 page

Delocalization of slowly damped eigenmodes on Anosov manifolds

We look at the properties of high frequency eigenmodes for the damped wave equation on a compact manifold with an Anosov geodesic flow. We study eigenmodes with spectral parameters which are asymptotically close enough to the real axis. We prove that such modes cannot be completely localized on subsets satisfying a condition of negative topological pressure. As an application, one can deduce the existence of a "strip" of logarithmic size without eigenvalues below the real axis under this dynamical assumption on the set of undamped trajectories.Comment: 28 pages; compared with version 1, minor modifications, add two reference

Some open questions in "wave chaos"

The subject area referred to as "wave chaos", "quantum chaos" or "quantum chaology" has been investigated mostly by the theoretical physics community in the last 30 years. The questions it raises have more recently also attracted the attention of mathematicians and mathematical physicists, due to connections with number theory, graph theory, Riemannian, hyperbolic or complex geometry, classical dynamical systems, probability etc. After giving a rough account on "what is quantum chaos?", I intend to list some pending questions, some of them having been raised a long time ago, some others more recent

Ancient conserved domains shared by animal soluble guanylyl cyclases and bacterial signaling proteins

BACKGROUND: Soluble guanylyl cyclases (SGCs) are dimeric enzymes that transduce signals downstream of nitric oxide (NO) in animals. They sense NO by means of a heme moiety that is bound to their N-terminal extensions. RESULTS: Using sequence profile searches we show that the N-terminal extensions of the SGCs contain two globular domains. The first of these, the HNOB (Heme NO Binding) domain, is a predominantly α-helical domain and binds heme via a covalent linkage to histidine. Versions lacking this conserved histidine and are likely to interact with heme non-covalently. We detected HNOB domains in several bacterial lineages, where they occur fused to methyl accepting domains of chemotaxis receptors or as standalone proteins. The standalone forms are encoded by predicted operons that also contain genes for two component signaling systems and GGDEF-type nucleotide cyclases. The second domain, the HNOB associated (HNOBA) domain occurs between the HNOB and the cyclase domains in the animal SGCs. The HNOBA domain is also detected in bacteria and is always encoded by a gene, which occurs in the neighborhood of a gene for a HNOB domain. CONCLUSION: The HNOB domain is predicted to function as a heme-dependent sensor for gaseous ligands, and transduce diverse downstream signals, in both bacteria and animals. The HNOBA domain functionally interacts with the HNOB domain, and possibly binds a ligand, either in cooperation, or independently of the latter domain. Phyletic profiles and phylogenetic analysis suggest that the HNOB and HNOBA domains were acquired by the animal lineage via lateral transfer from a bacterial source

YAPA: A generic tool for computing intruder knowledge

Reasoning about the knowledge of an attacker is a necessary step in many formal analyses of security protocols. In the framework of the applied pi calculus, as in similar languages based on equational logics, knowledge is typically expressed by two relations: deducibility and static equivalence. Several decision procedures have been proposed for these relations under a variety of equational theories. However, each theory has its particular algorithm, and none has been implemented so far. We provide a generic procedure for deducibility and static equivalence that takes as input any convergent rewrite system. We show that our algorithm covers most of the existing decision procedures for convergent theories. We also provide an efficient implementation, and compare it briefly with the tools ProVerif and KiSs