Relative stability of linear and cyclic configurations of systems containing four atoms of nitrogen,carbon, or oxygen

Conclusions The present article has been devoted to an investigation of the relative stability of various conceivable structures of systems X₄ (where X=C, CH, N, or O). We regard the comparative regularities which we have discovered as reliable, in spite of the use of MHM, in which no account is taken in any explicit way of the interelectronic interaction. We have considered homoatomic systems, where, on the qualitative side many conclusions are essentially of a theoretical-group character, while from a quantitative point of view the accuracy of the results obtained is increased because of the justifiable similarities assumed in the approximations of the matrix elements (both diagonal and nondiagonal). We have also investigated the geometry of the molecules, a problem of the solution of which the MHM method (as shown by comparing this with the SSP-MO [26] method) is remarkably effective.The main results of the present work are in our view to be found in the great similarity discovered in the structures of the systems C₄H₄ and N₄ (and their appreciable difference from the structure of the O₄ molecule). Therefore, returning to the over-all problem formulated at the beginning of this article, we are able to emphasize that the hypothesis of the possible formation of the N₄ system by combination of molecular nitrogen in certain complexes of the transition metals [1] is still further confirmed.N. S. Kurnakov Institute of General and Inorganic Chemistry of the Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 10, No. 4, July–August, 1969.     

Circumventing air bubbles in microfluidic systems and quantitative continuous-flow PCR applications

Polymerase chain reaction (PCR) is an essential part of research based on genomics or cell analysis. The development of a microfluidic device that would be suitable for high-temperature-based reactions therefore becomes an important contribution towards the integration of micro-total analysis systems (μTAS). However, problems associated with the generation of air bubbles in the microchannels before the introduction of the assay liquid, which we call the “initial start-up” in this study, made the flow irregular and unstable. In this report, we have tried to address these problems by adapting a novel liquid-flow method for high-temperature-based reactions. A PDMS-based microfluidic device was fabricated by soft-lithography techniques and placed on a cartridge heater. The generation of the air bubbles was prevented by introducing the fluorinated oil, an inert and highly viscous liquid, as the cap just before the introduction of the sample solutions into the microchannels. The technique was applied for continuous-flow PCR, which could perform PCR on-chip in a microfluidic system. For the evaluation of practical accuracy, plasmid DNA that serves as a reference molecule for the quantification of genetically modified (GM) maize was used as the template DNA for continuous-flow PCR. After PCR, the products were collected in a vial and analyzed by gel electrophoresis to confirm the accuracy of the results. Additionally, quantitative continuous-flow PCR was performed using TaqMan technology on our PCR device. A laser detection system was also used for the quantitative PCR method. We observed a linear relationship between the threshold cycle (Ct) and the initial DNA concentration. These results showed that it would be possible to quantify the initial copies of the template DNA on our microfluidic device. Accurate quantitative DNA analysis in microfluidic systems is required for the integration of PCR with μTAS, thus we anticipate that our device would have promising potential for applications in a wide range of research.     

Experiment of C-Band Wavelength Conversion in a Silicon Waveguide Pumped by Dispersed Femtosecond Laser Pulse

We experimentally demonstrate the C-band wavelength conversion using four-wave mixing in a 17-mm-long silicon-on-insulator waveguide pumped by a dispersed mode-locked femtosecond laser pulse. The idler can be observed with an incident average pump power lower than 4 dBm, and about 35 nm of conversion bandwidth from 1530nm to 1565nm is measured by using a 1550-nm pump wavelength. The pulse-pumped efficiency is demonstrated to be higher, by more than 22 dB, than the cw-pumped efficiency. The conversion efficiency variations with respect to the pump and signal powers are also investigated.     

A search method for optimal control of a flow shop system of traditional machines

We consider a convex and nondifferentiable optimization problem for deterministic flow shop systems in which the arrival times of the jobs are known and jobs are processed in the order they arrive. The decision variables are the service times that are to be set only once before processing the first job, and cannot be altered between processes. The cost objective is the sum of regular costs on job completion times and service costs inversely proportional to the controllable service times. A finite set of subproblems, which can be solved by trust-region methods, are defined and their solutions are related to the optimal solution of the optimization problem under consideration. Exploiting these relationships, we introduce a two-phase search method which converges in a finite number of iterations. A numerical study is held to demonstrate the solution performance of the search method compared to a subgradient method proposed in earlier work.     

Secondary-Ion Mass Spectrometry Images Cardiolipins and Phosphatidylethanolamines at the Subcellular Level

Millions of diverse molecules constituting the lipidome act as important signals within cells. Of these, cardiolipin (CL) and phosphatidylethanolamine (PE) participate in apoptosis and ferroptosis, respectively. Their subcellular distribution is largely unknown. Imaging mass spectrometry is capable of deciphering the spatial distribution of multiple lipids at subcellular levels. Here we report the development of a unique 70 keV gas-cluster ion beam that consists of (CO₂)_n⁺(n>10 000) projectiles. Coupled with direct current beam buncher-time-of-flight secondary-ion mass spectrometry, it is optimized for sensitivity towards high-mass species (up to m/z 3000) at high spatial resolution (1 μm). In combination with immunohistochemistry, phospholipids, including PE and CL, have been assessed in subcellular compartments of mouse hippocampal neuronal cells and rat brain tissue.     

Anomalous Hall effect for the phonon heat conductivity in paramagnetic dielectrics

The theory of the anomalous Hall effect for the heat transfer in a parmagnetic dielectric, discovered by Strohm, Rikken, and Wyder [Phys. Rev. Lett. 95, 155901 (2005)]10.1103/PhysRevLett.95.155901, is developed. The appearance of the phonon heat flux normal to both the temperature gradient and the magnetic field is connected with the interaction of magnetic ions with the crystal field oscillations. In crystals with an arbitrary phonon spectrum this interaction creates the elliptical polarization of phonons. The kinetics related to phonon scattering induced by the spin-phonon interaction determines an origin of the off-diagonal phonon density matrix. The combination of both factors is decisive for the phenomenon under consideration.     

Oxidative dimerization of alcohols in the presence of nitroxyl radical–iodine catalytic system

Pyridine catalyzes oxidation of alcohols with 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl–iodine catalytic system at room temperature. Symmetric esters are formed in good yields.     

Collapse of the Fano Resonance Caused by the Nonlocality of the Majorana State

JETP Letters - Owing to the nonlocal character of the Majorana state, the corresponding excitations are of great interest. It is demonstrated that the direct consequence of such nonlocality is the...