A polarizable, four-point-charge model of water with size variation

The proposed model is classical, polarizable and can change its size responding to the impact of the surroundings. We introduce a qualitative theory which simultaneously changes polarization, repulsion and size. Larger electric fields in condensed phases pull the molecules closer and induce larger polarization than in gas phase. However, this causes exponential increase in repulsion as a result of overlapping electron clouds. To decrease the impact of this repulsion the electron cloud contracts slightly, which decrease its polarization. Since the size of the molecule is determined by the extension of its electron cloud, there will be a subtle equilibrium determined by the actual strength of the polarization force, the repulsion and the size of the molecule.Using the principles above, we developed a model and carried out numerical calculations. The properties of the dimer practically reproduce the experimental values. The estimates of the energy, the density and the structure of liquid water and hexagonal ice are also excellent.     

Improving LED Efficiency with the New Polymorph β-Ca1−xSrxAlSiN3:Eu2+

Innovative materials for phosphor-converted white light-emitting diodes (pc-LEDs) are much sought after due to the huge potential of the LED technology to reduce energy consumption worldwide. One of the main levers for further improvements are the conversion phosphors. The system Ca_1−xSr_xAlSiN₃:Eu²⁺ currently provides one of the most important red-emitting phosphors for pc-LEDs. We report the discovery of the new polymorph β-Ca_1−xSr_xAlSiN₃:Eu²⁺ which allows for significant improvements to LED efficacies. It crystallizes in the orthorhombic space group Pbcn with lattice parameters a=982.43(10) pm, b=575.2(1) pm and c=516.12(5) pm. Compared to α-Ca_1−xSr_xAlSiN₃:Eu²⁺, its emission shows a significantly reduced spectral full-width at half maximum (FWHM). With that, we demonstrated 3 % efficacy increase for white light-emitting pc-LEDs. The new polymorph can easily be industrialised, because the synthesis works on the same equipment as α-Ca_1−xSr_xAlSiN₃:Eu²⁺.     

Explicit N-fold Darboux transformation for the classical Boussinesq system and multi-soliton solutions

In this Letter, a systematic method is presented to construct the N-fold Darboux transformation with multi-parameters for a spectral problem associated with a classical Boussinesq system. As an application, we obtain the new soliton solutions of the classical Boussinesq system.     

Guanidiniocarbonylpyrrole–Aryl Derivatives: Structure Tuning for Spectrophotometric Recognition of Specific DNA and RNA Sequences and for Antiproliferative Activity

We present a systematic study of different guanidiniocarbonylpyrrole‐aryl derivatives designed to interact with DNA or RNA both through intercalation of an aromatic moiety into the base stack of the nucleotide and through groove binding of a guanidiniocarbonylpyrrole cation. We varied 1) the size of the aromatic ring (benzene, naphthalene, pyrene and acridine), 2) the length and flexibility of the linker connecting the two binding groups, and 3) the total number of positive charges present at different pH values. The compounds and their interactions with DNA and RNA were studied by UV/Vis, fluorescence and CD spectroscopy. Antiproliferative activities against human tumour cell lines were also determined. Our studies show that efficient interaction with, for example, DNA requires a significantly large aromatic ring (pyrene) connected through a flexible linker to the pyrrole moiety. However, a positive charge, as in 12 , is also needed. Compound 12 allows for base‐pair‐selective recognition of ds‐DNA at physiological pH values. The antiproliferative activities of these compounds correlate with their binding affinities towards DNA, suggesting that their biological effects are most probably due to DNA binding.     

Born's rule from classical random fields

This Letter is an attempt to go beyond QM. In our approach density operators of QM can be represented as covariance operators of classical random fields. Born's rule can be obtained from measurement theory for classical random field under the assumption that the probability of detection of field is proportional to the power of this field.     

On gravity localization under Lorentz violation in warped scenario

Recently Rizzo studied the Lorentz Invariance Violation (LIV) in a brane scenario with one extra dimension where he found a non-zero mass for the four-dimensional graviton. This leads to the conclusion that five-dimensional models with LIV are not phenomenologically viable. In this work we re-examine the issue of Lorentz Invariance Violation in the context of higher-dimensional theories. We show that a six-dimensional geometry describing a string-like defect with a bulk-dependent cosmological constant can yield a massless 4D graviton, if we allow the cosmological constant variation along the bulk, and thus can provides a phenomenologically viable solution for the gauge hierarchy problem.     

The Ruin Probability in the Presence of Extended Regular Variation and Optimal Investment

Considering the classical model with risky investment, we are interested in the ruin probability that is minimized by a suitably chosen investment strategy for a capital market index. For claim sizes with common distribution of extended regular variation, starting from an integro-differential equation for the maximal survival probability, we find that the corresponding ruin probability as a function of the initial surplus is also extended regular variation.     

Hydrolysis of Organophosphate Esters: Phosphotriesterase Activity of Metallo‐β‐lactamase and Its Functional Mimics

The phosphotriesterase (PTE) activity of a series of binuclear and mononuclear zinc(II) complexes and metallo‐β‐lactamase (mβl) from Bacillus cereus was studied. The binuclear complex 1 , which exhibits good mβl activity, shows poor PTE activity. In contrast, complex 2 , a poor mimic of mβl, exhibits much higher activity than 1 . The replacement of Cl^? ligands by OH^? is important for the high PTE activity of complex 2 because this complex does not show any catalytic activity in methanol. The natural enzyme mβl from B. cereus is also found to be an inefficient catalyst in the hydrolysis of phosphotriesters. These observations indicate that the binding of β‐lactam substrates at the binuclear zinc(II) center is different from that of phosphotriesters. Furthermore, phosphodiesters, the products from the hydrolysis of triesters, significantly inhibit the PTE activity of mβl and its functional mimics. Although the mononuclear complexes 3 and 4 exhibited significant mβl activity, these complexes are found to be almost inactive in the hydrolysis of phosphotriesters. These observations indicate that the elimination of phosphodiesters from the reaction site is important for the PTE activity of zinc(II) complexes.