Copper(I)-anilide complex [Na(phen)3][Cu(NPh2)2]: an intermediate in the copper-catalyzed N-arylation of N-phenylaniline

Complex [Na(phen)₃][Cu(NPh₂)₂] ( 2 ), containing a linear bis(N‐phenylanilide)copper(I) anion and a distorted octahedral tris(1,10‐phenanthroline)sodium counter cation, has been isolated from the catalytic C? N cross‐coupling reaction with the CuI/phen/tBuONa (phen=1,10‐phenanthroline) catalytic system. Complex 2 can react with 4‐iodotoluene to produce 4‐methyl‐N,N‐diphenylaniline ( 3 a ) with 70.6 % yield. In addition, 2 can work as an effective catalyst for C? N coupling under the same reaction conditions, thus indicating that 2 is the intermediate of the catalytic system. Both [Cu(NPh₂)₂]^? and [Cu(NPh₂)I]^? have been observed by in situ electron ionization mass spectrometry (ESI‐MS) under catalytic reaction conditions, thus confirming that they are intermediates in the reaction. A catalytic cycle has been proposed based on these observations. The molecular structure of 2 has been determined by single‐crystal X‐ray diffraction analysis.     

Urine analysis in microfluidic devices

Microfluidics has attracted considerable attention since its early development in the 1980s and has experienced rapid growth in the past three decades due to advantages associated with miniaturization, integration and automation. Urine analysis is a common, fast and inexpensive clinical diagnostic tool in health care. In this article, we will be reviewing recent works starting from 2005 to the present for urine analysis using microfluidic devices or systems and to provide in-depth commentary about these techniques. Moreover, commercial strips that are often treated as chips and their readers for urine analysis will also be briefly discussed. We start with an introduction to the physiological significance of various components or measurement standards in urine analysis, followed by a brief introduction to enabling microfluidic technologies. Then, microfluidic devices or systems for sample pretreatments and for sensing urinary macromolecules, micromolecules, as well as multiplexed analysis are reviewed, in this sequence. Moreover, a microfluidic chip for urinary proteome profiling is also discussed, followed by a section discussing commercial products. Finally, the authors' perspectives on microfluidic-based urine analysis are provided. These advancements in microfluidic techniques for urine analysis may improve current routine clinical practices, particularly for point-of-care (POC) applications.     

A Novel Method for Screening G‐quadruplex Stabilizers to Human Telomeres

We present a simple method based on the Cu²⁺ induced unfolding of G‐quadruplex (G4) of human telomere sequence d[AG₃(T₂AG₃)₃] to screen a number of 3,6‐bis(1‐methyl‐4‐vinylpyridinium)carbazole diiodide (BMVC) analogues for better G4 stabilizers. Using circular dichroism (CD), the screening results suggest that the tri‐cations of 9‐substituted BMVC derivatives are better G4 stabilizers than the bi‐cations of BMVC. In addition, 3,6‐bis(1‐methyl‐4‐vinylpyrazinium)carbazole diiodide (BMVC4) is likely a better core molecule than BMVC for G4 stabilizers.     

Synthesis of the phenanthrene and cyclohepta[a]naphthalene skeletons via gold(I)-catalyzed intramolecular cyclization of unactivated cyclic 5-(2-arylethyl)-1,3-dienes

The gold(I)-catalyzed hydroarylation of cyclohexa-1,3-dienes bearing an aryl group and a gem-diester in the tether proceeds in a 1,4-addition manner and in a diastereoselective fashion to afford perhydrophenanthrene rings. The reaction proceeded via attack of the aryl group onto the gold-activated cyclic dienes followed by rearomatization and protodeauration to generate perhydrophenanthrenes in good yields. This hydroarylation can be applied to the synthesis of perhydrocyclohepta[a]naphthalenes from aryl-tethered cycloheptadienes and the gold(I) catalyst.     

A copper(II) complex as an intermediate of copper(I)-catalyzed C-N cross coupling of N-phenylaniline with aryl halide by in situ ESI-MS study

Complexes [Cu(NPh(2))(2)](-), [Cu(NPh(2))I](-) and K[Cu(phen)(NPh(2)) (p-tolyl)](+) were observed by in situ electrospray ionization mass spectrometry (ESI-MS) analysis of the copper(I)-catalyzed C-N coupling reaction under the catalytic reaction condition indicating that they are intermediates in the reaction. A catalytic cycle composed of a free radical path and a 2e oxidative addition path is proposed based on these observations.     

Intermediates of copper(I)-catalyzed C-S cross coupling of thiophenol with aryl halide by in situ ESI-MS study

Complexes [Cu(SPh)(2)](-), [Cu(SPh)I](-) and K[Cu(SPh)(2)(Ph)](+) were observed by in situ electrospray ionization mass spectrometry (ESI-MS) analysis of the copper(i)-catalyzed C-S coupling reaction under catalytic reaction conditions indicating that they are intermediates in the reaction. A catalytic cycle was proposed based on these observations.     

Parametrized variational inequality approaches to generalized Nash equilibrium problems with shared constraints

We consider the generalized Nash equilibrium problem (GNEP), in which each player’s strategy set may depend on the rivals’ strategies through shared constraints. A practical approach to solving this problem that has received increasing attention lately entails solving a related variational inequality (VI). From the viewpoint of game theory, it is important to find as many GNEs as possible, if not all of them. We propose two types of parametrized VIs related to the GNEP, one price-directed and the other resource-directed. We show that these parametrized VIs inherit the monotonicity properties of the original VI and, under mild constraint qualifications, their solutions yield all GNEs. We propose strategies to sample in the parameter spaces and show, through numerical experiments on benchmark examples, that the GNEs found by the parametrized VI approaches are widely distributed over the GNE set.     

Asset returns and volatility clustering in financial time series

An analysis of the stylized facts in financial time series is carried out. We find that, instead of the heavy tails in asset return distributions, the slow decay behaviour in autocorrelation functions of absolute returns is actually directly related to the degree of clustering of large fluctuations within the financial time series. We also introduce an index to quantitatively measure the clustering behaviour of fluctuations in these time series and show that big losses in financial markets usually lump more severely than big gains. We further give examples to demonstrate that comparing to conventional methods, our index enables one to extract more information from the financial time series.     

White light interferometric detection of unpolarized light for complete Stokesmetric optical coherence tomography

Optical coherence tomography (OCT) relies on interference between a polarized reference and the target reflection. Thus, it has generally been impossible to detect any unpolarized part in the signal. Here, we demonstrate a scheme that overcomes this limitation. Using a combination of heterodyning and filtering, we realize a polarization-sensitive OCT system capable of measuring the full Stokes vector, including the depolarized part. Based on such a system, we perform full Stokesmetric imaging of different layers in a porcine tendon sample. The complete 4 × 4 backscattering Muellermetric images of one layer are acquired and investigated.     

Optimized laser cutting on light guide plates using grey relational analysis

This paper present the optimum conditions for direct CO₂ laser cutting of 6-mm-thick polymethylmethacrylate (PMMA) for backlit module applications. The influence of the major processing parameters on the optical transmittance ratio and surface roughness of cut samples material have been discussed. In order to assess the effects of several operational parameters on multiple-performance characteristics, we applied the grey relational analysis method. In this paper, we studied the effects of several laser direct cut parameters, such as assisted gas-flow rate, pulse repetition frequency, cutting speed, and focus position to achieve optimum characteristics for two product characteristics, optical transmittance ratio and work-piece surface roughness. The study involved nine experiments based on an orthogonal array, and results indicate the optimal process parameters as 20 NL/min for assisted-gas flow rate, 5 kHz for pulse repetition frequency, 2 mm/s for cutting speed, and 0 mm for laser focusing position. Additionally, by analyzing the grey relational grade, we found that the assisted-gas flow rate has more influence than any other single parameter.