XYZH systems as potential 1,3-dipoles. Part 62: 1,3-Dipolar cycloaddition reactions of metallo-azomethine ylides derived from α-iminophosphonates

Metallo-azomethine ylides, generated from iminophosphonates in combination with LiBr or AgOAc and bases Et₃N, DBU, t-butyl tetramethylguanidine(BTMG) undergo cycloaddition to give dialkyl pyrrolidine-2-phosphonates along with the corresponding Michael adduct in some cases. Cycloadditions with the chiral dipolarophile 5R-(1′R,2′S,5′R-menthyloxy)-2-(5H)-furanone (MOF) afforded enantiopure cycloadducts.     

New approach to relativity and gravitation

A theory of gravitation, where the stress-energy tensor of the gravitational field is part of the source term of the geometric curvatures, is presented. The theory predicts correctly all the Newtonian and post-Newtonian effects of gravity currently considered as crucial. For extremely strong and nonstatic fields, such as are presumed to exist in quasars and exploding stars, new predictions differing from those of the conventional theory are implied. In the correspondence limit of special relativity the theory recovers the conservation of energy-momentum properly and seems to represent a more satisfactory extension of special theory of relativity.     

Principal Congruence Subgroups of Hecke Groups H（√q）

Using the notion of quadratic reciprocity, we discuss the principal congruence subgroups of the Hecke groups H（√q）,q 〉 5 prime number.     

Light harvesting and efficient energy transfer in a boron-dipyrrin (BODIPY) functionalized perylenediimide derivative

[reaction: see text] Click chemistry has been successfully applied in the synthesis of a bay region tetraboron-dipyrrin (BODIPY) appended perylenediimide (PDI). This light-harvesting molecule presents a large cross section for the absorption of light in the visible region. Excitation energy is efficiently channeled to the perylenediimide core. This novel antenna system is the first demonstration of the efficiency of energy transfer in a BODIPY-PDI bichromophoric system and appears to be highly promising for the design and synthesis of similar dendritic structures.     

A family of p-adic twisted interpolation functions associated with the modified Bernoulli numbers

The main purpose of this paper is to construct a family of modified p-adic twisted functions, which interpolate the modified twisted q-Bernoulli polynomials and the generalized twisted q-Bernoulli numbers at negative integers. We also give some applications and examples related to these functions and numbers.     

Collective firing regularity of a scale-free Hodgkin–Huxley neuronal network in response to a subthreshold signal

We consider a scale-free network of stochastic HH neurons driven by a subthreshold periodic stimulus and investigate how the collective spiking regularity or the collective temporal coherence changes with the stimulus frequency, the intrinsic noise (or the cell size), the network average degree and the coupling strength. We show that the best temporal coherence is obtained for a certain level of the intrinsic noise when the frequencies of the external stimulus and the subthreshold oscillations of the network elements match. We also find that the collective regularity exhibits a resonance-like behavior depending on both the coupling strength and the network average degree at the optimal values of the stimulus frequency and the cell size, indicating that the best temporal coherence also requires an optimal coupling strength and an optimal average degree of the connectivity.     

In situ palladium/N-heterocyclic carbene complex catalyzed carbonylative cross-coupling reactions of arylboronic acids with 2-bromopyridine under CO pressure: efficient synthesis of unsymmetrical arylpyridine ketones and their antimicrobial activities

Transition Metal Chemistry - The carbonylative Suzuki cross-coupling of 2-bromopyridine with various boronic acids to prepare unsymmetrical arylpyridine ketones has been carried out using...     

Measurement of temperature, density, and particle transport with localized dopants in wire-array Z pinches

Axially localized NaF dopants are coated onto Al cylindrical wire arrays in order to act as spectroscopic tracers in the stagnated z-pinch plasma. Non-local-thermodynamic-equilibrium kinetic models fit to Na K-shell lines provide an independent measurement of the density and temperature that is consistent with spectroscopic analysis of K-shell emissions from Al and an alloyed Mg dopant. Axial transport of the Na dopant is observed, enabling quantitative study of instabilities in dense z-pinch plasmas.     

Usage of deep eutectic solvents for the digestion and ultrasound-assisted liquid phase microextraction of copper in liver samples

In this study, we used deep eutectic solvents for digestion and ultrasound-assisted emulsification liquid phase microextraction (UA-ELPME) of copper in liver samples. Different types of DESs were prepared for digestion and microextraction steps. DESs consisting of lactic acid and choline chloride for the digestion step and DESs consisting of tetrabuthylamonium chloride and decanoic acid for ultrasound-assisted emulsification liquid phase microextraction were used in this method. The liver samples were digested by using DES-based digestion method. After digestion step, Cu(II) ions in aqueous phase were complexed with sodium dimethyl dithiocarbamate (NaDMDTC) and the obtained hydrophobic complex was extracted to tetrabuthylamonium chloride-decanoic acid DES phase. A microsample injection system coupled with flame atomic absorption spectrometer (MS-FAAS) was used in the detection of copper. LOD, LOQ, PF and % RSD were determined as 4.00, 13.2 µg L^??1, 10 and 3.2%, respectively. The proposed microextraction procedure was successfully applied to copper contents of the liver samples.