Biomolecule-directed assembly of nanoscale building blocks studied via lattice Monte Carlo simulation

We perform lattice Monte Carlo simulations to study the self-assembly of functionalized inorganic nanoscale building blocks using recognitive biomolecule linkers. We develop a minimal coarse-grained lattice model for the nanoscale building block (NBB) and the recognitive linkers. Using this model, we explore the influence of the size ratio of linker length to NBB diameter on the assembly process and the structural properties of the resulting aggregates, including the spatial distribution of NBBs and aggregate topology. We find the constant-kernel Smoluchowski theory of diffusion-limited cluster-cluster aggregation describes the aggregation kinetics for certain size ratios.     

Reaktion von arylbromiden mit cobaloxim(I). Röntgenstrukturanalyse des umsetzungsproduktes von cis-3-ethoxycyclobutylbrosylat mit (pyridin)cobaloxim(I)

Reactions of aryl bromides of a p-benzenesulfonyloxy derivative (I) and of p-trifluoromethylbromobenzene (V) with (pyridine)cobaloxim(I) (II) yield the corresponding aryl(pyridine)cobaloxim(III). The structure of the complex derived from I has been determined by X-ray structure analysis.     

Synthesis of 4-methoxy-2,3,5-trimethylpyridine: a specific building block for compounds with gastric-acid inhibiting activity

A new synthesis of 4-methoxy-2,3,5-trimethylpyridine (2), an important building block for the preparation of gastric-acid inhibiting compounds, is described. Condensation of ethyl 3-amino-2-methyl-2-butenoate (3) and diethyl 2-methylmalonate (4) gives 4-hydroxy-3,5,6-trimethyl-2(1H)-pyridone 5. Reaction of 5 with phosphoryl chloride affords 2,4-dichloro-3,5,6-trimethylpyridine (9a), which, upon hydrogenolysis with palladium on charcoal, gives 2,3,5-trimethylpyridine (10). However, selective hydrogenolysis in acidic solution yields 4-chloro-2-3-5-trimethylpyridine (11). Substitution of the chlorine in 11 with methoxide ion gives 4-methoxy-2,3,5-trimethylpyridine (2), which can be oxidized to the corresponding N-oxide (13). This constitutes a new and efficient route to compound 2 in an overall yield of 43%.     

Modelling and control of natural convection in canned foods

In this paper we study mathematically an industrial problemrelated to sterilization processes involving heat transfer bynatural convection. We give results of existence and regularityfor the solution of this problem. We recast the whole problemas an optimal control problem with pointwise constraints onthe state and the control in order to ensure the reduction ofmicroorganism concentration and the retention of nutrients,and to save energy. Finally, we give results on existence ofthe optimal solution and optimality conditions for its characterization.     

Piaselenol—Piaselenolium—Pentaiodid (C6H4N2Se · C6H5N2Se+I3− · I2), eine Struktur mit Polyiodid-schichten

Piaselenole—Piaselenolium—Pentaiodide (C₆H₄N₂Se · C₆H₅N₂Se⁺ I₃^? · I₂), a Structure with Polyiodide Layers The title compound crystallizes in the monoclinic space group P2₁/n with a = 9.320(3), b = 13.812(2), c = 17.159(3) Å, β = 96.11(2)°, V = 2196.3 ų, Z = 4. There occur no isolated I^5? anions but layer-shaped polyiodide aggregates built up by linear, asymmetric I₃^? anions and I₂ molecules. Almost linear triiodide chains are connected by I₂ molecules in a novel type of arrangement to form slightly puckered layers. The polyiodide layers contain several substructures known from other examples. The piaselenole and its conjugated acid, the piaselenolium cation, form a ribbon-like quasi-polymer in which the two components are alternating. They are connected in turns by a linear NH? N hydrogen bridge (N? N: 2.844 Å) and by a so called (SeN)₂-connectivity parallelogram, in which Se? N bonds and Se? N contacts are adjacent. Here we found a very short Se? N contact distance of 2.691 Å. The bond distances of piaselenole (Se? N: 1.787(3) Å, N? C: 1.318(5) Å, C? C: 1.453(8) Å) and also the angles are equal or similar to those occuring in other 1,2,5-selenadiazoles. The protonation of one N in the SeN₂ unit results in a loss of symmetry and significant changes in bonding distances and angles.     

Search for the lepton family number violating process nu(mu)e(-) --> mu(-)nu(e)

The NuTeV experiment at Fermilab has used a sign-selected neutrino beam to perform a search for the lepton number violating process nu(mu)e(-)-->mu(-)nu(e), and to measure the cross section of the standard model inverse muon decay process nu(mu)e(-)-->mu(-)nu(e). NuTeV measures the inverse muon decay asymptotic cross-section slope sigma/E to be (13.8 +/- 1.2 +/- 1.4) x 10(-42) cm(2)/GeV. The experiment also observes no evidence for lepton number violation and places one of the most restrictive limits on the cross-section ratio sigma(nu(mu)e(-)-->mu(-)nu(e))/sigma(nu(mu)e(-)-->mu(-)nu(e)) < or = 1.7% at 90% C.L. for V-A couplings and < or = 0.6% for scalar couplings.     

Search for a 33.9 MeV/c(2) neutral particle in pion decay

The E815 (NuTeV) neutrino experiment has performed a search for a 33. 9 MeV/c(2) weakly interacting neutral particle produced in pion decay. Such a particle may be responsible for an anomaly in the timing distribution of neutrino interactions in the KARMEN experiment. E815 has searched for this particle's decays in an instrumented decay region; no evidence for this particle was found. The search is sensitive to pion branching ratios as low as 10(-13).