Hydrogen-bond strengths by magnetically induced currents

We present here a "non-invasive" computational method to estimate the strength of individual hydrogen bonds using magnetically induced currents. The method is calibrated using H-bonding dimers, and applied on Watson-Crick DNA base pairs and proton wires in carbonic anhydrase.     

Sobolev Spaces with Zero Boundary Values on Metric Spaces

We generalize the definition of the first order Sobolev spaces with zero boundary values to an arbitrary metric space endowed with a Borel regular measure. We show that many classical results extend to the metric setting. These include completeness, lattice properties and removable sets.     

The Essential Norm of Weighted Composition Operators on Weighted Banach Spaces of Analytic Functions

For a wide class of radial weights we calculate the essential norm of a weighted composition operator uC_j{uC_\varphi} on the weighted Banach spaces of analytic functions in terms of the analytic function u \colon \mathbb D ? \mathbb C{u \colon \mathbb D \to \mathbb C} and the nth power of the analytic selfmap j{\varphi} of the open unit disc \mathbb D{\mathbb D} . We also apply our result to calculate the essential norm of composition operators acting on Bloch type spaces with general radial weights.     

Controlled oxidation of iron nanoparticles in chemical vapour synthesis

Enteric-coated formulations can delay the release of drugs until they have passed through the stomach. However, high concentration of drugs caused by rapidly released in the small intestine leads to the intestinal damage, and frequent administration would increase the probability of missing medication and reduce the patient compliance. To solve the above-mentioned problems, aspirin-loaded enteric-coated sustained-release nanoparticles with core–shell structure were prepared via one-step method using coaxial electrospray in this study. Eudragit L100-55 as pH-sensitive polymer and Eudragit RS as sustained-release polymer were used for the outer coating and inner core of the nanoparticles, respectively. The maximum loading capacity of nanoparticles was 23.66 % by changing the flow rate ratio of outer/inner solutions, and the entrapment efficiency was nearly 100 %. Nanoparticles with core–shell structure were observed via fluorescence microscope and transmission electron microscope. And pH-sensitive and sustained drug release profiles were observed in the media with different pH values (1.2 and 6.8). In addition, mild cytotoxicity in vitro was detected, and the nanoparticles could be taken up by Caco-2 cells within 1.0 h in cellular uptake study. These results indicate that prepared enteric-coated sustained-release nanoparticles would be a more safety and effective carrier for oral drug delivery.     

The effect of reactor irradiation on the dielectric loss peaks of Nylon and Mylar

The effect of irradiation on the dielectric properties of nylon 66.6 and Mylar was studied. In the case of nylon the dielectric loss peak at 350 K measured with an annular frequency of 10⁴ l/s disappeared due to irradiation and the peak at higher temperaturcs shifted to still higher temperatures. In Mylar the α-peak grew in magnitude, indicating an increase in amorphousness, while the β-peak decreased. A rough estimate for the decrease in the magnitude of the effective number of dipoles is presented. The irradiation was carried out up to fast neutron fluence of 3 × 10¹⁷ nvt and gamma dose of 1 × 10⁹ rad.     

Vague objects and phenomenal wholes

We consider the so-called problem of the many, formulated by Peter Unger. It arises because ordinary material things do not have precise boundaries: it is always possible to find borderline parts of which it is not true to say either that they are parts or that they are not. Unger’s conclusion is that there are no ordinary things at all. We describe the solutions of Peter van Inwagen and David Lewis, and make some critical comments upon them. After that we present our own suggestion which is based on ideas developed by Leibniz in connection with problems of unity and plurality. We suggest that what the problem of the many teaches us is that in order to understand what ordinary things are, we have to take seriously the Leibnizian-Kantian distinction between phenomena and things-in-themselves.     

Pentacarbonylmetallderivatevon phosphinidenen und diphosphenen

Reaction of Na₂[M₂CO₁₀] (M = Cr, Mo, W) with RPCl₂ (R = mesityl, CH(SiMe₃)₂) yields, depending on the reaction conditions as well as on the steric demand of R, phosphinidene compounds [(CO)₅M]₂PR and diphosphene species [(CO)₅M]_nRPPR (n = 1, 2). With especially bulky substituents mono-nuclear diphosphene derivatives are the preferred reaction products. For dinuclear diphosphene compounds the Z-configuration is induced when R = mesityl while in other cases the E-configuration is the more stable form.The structures of the new compounds are documented by X-ray analyses of three examples. The accumulated material allows for a comparative discussion of the ³¹P NMR spectra, which often show unconventional low-field shifts (up to 1216 ppm), as well as of the characteristic UV/VIS spectra. For all compounds IR, ¹H NMR and mass spectra as well as correct analyses are presented.     

Homeomorphisms of the Heisenberg group preserving BMO

We provide a new geometric proof of Reimann’s theorem characterizing quasiconformal mappings as the ones preserving functions of bounded mean oscillation. While our proof is new already in the Euclidean spaces, it is applicable in Heisenberg groups as well as in more general stratified nilpotent Carnot groups.     

Capacity and Potential Estimates for Quasiminimizers

We obtain estimates for quasiminimizing potentials and their level sets. A new method, based on one dimensional quasiminimizers, is used. The connection of these estimates and the maximum principle is studied.