‘One-flask’ synthesis to 3,5-disubstituted 1,2,4-triazoles from aldehydes with hydrazonoyl hydrochlorides via 1,3-dipolar cycloaddition

A new ‘one-flask’ synthesis of 3,5-disubstituted 1,2,4-triazoles has successfully been developed to synthesize a series of 3,5-disubstituted 1,2,4-triazoles. The transformation involves the 1,3-dipolar cycloaddition reaction of hydrazonoyl hydrochlorides with oxime intermediates prepared from aldehydes with hydroxylamine hydrochloride in the presence of excess amount of triethylamine. In this ‘one-flask’ 1,3-dipolar reaction, hydrazonoyl hydrochlorides was concerned as the masked 1,3-dipole nitrilimine under basic condition. Furthermore, this newly developed methodology can be applied to various aldehyde substrates including aliphatic, cyclic aliphatic, aromatic, and heterocyclic aldehydes.     

Quenching Behavior of the Electrochemiluminescence of Ru(bpy)32+/TPrA System by Phenols on a Smartphone-Based Sensor

Phenolic compounds such as vanillic and p-coumaric acids are pollutants of major concern in the agro-industrial processing, thereby their effective detection in the industrial environment is essential to reduce exposure. Herein, we present the quenching effect of these compounds on the electrochemiluminescence (ECL) of the Ru(bpy)₃²⁺/TPrA (TPrA=tri-n-propylamine) system at a disposable screen-printed carbon electrode. Transient ECL profiles are obtained from multiple video frames following 1.2 V application by a smartphone-based ECL sensor. A wide range of detection was achieved using the sensor with limit of detection of 0.26 μM and 0.68 μM for vanillic and p-coumaric acids, respectively. The estimated quenching constants determined that the quenching efficiency of vanillic acid is at least two-fold that of p-coumaric acid under the current detection conditions. The present ECL quenching approach provided an effective method to detect phenolic compounds using a low-cost, portable smartphone-based ECL sensor.     

Many-particle rapidity correlations in light-ion interactions at the CERN intersecting storage rings

Many-particle rapidity correlations have been studied for αα,dd, andpp interactions at the CERN Intersecting Storage Rings using the Split-Field Magnet detector, and basing the investigating on the distributions of rapidity gaps between particles. In the framework of a simple cluster model, it is found that all the data samples have similar features and that the events contain clusters of two different types.     

Volume changes during stress relaxation in polyethylene

This paper presents the results of an experimental study of the stress relaxation behaviour of PE where the focus was on determination of the volume changes taking place during the relaxation process. The dimensions of the samples were followed using a specially designed non-disturbing extensometer. The extensometer data were confirmed in experiments where the volume was measured with a specially designed liquid stress dilatometer. The bulk of the results was obtained with LDPE and LLDPE. High density polyethylene was shown to behave similarly.The decrease in volume, corresponding to an increasing Poisson's ratio, during relaxation was approximately linear with log time. Volume vs. stress diagrams were linear; the values of the apparent bulk modulus calculated from them were only slightly higher than those obtained from the stress-strain curves. Grüneisen parameter was measured and compared with reported values. Possible similarities between the volume change during stress relaxation and that occuring during the process of physical ageing are discussed.     

宇宙线大气簇射μ子定点密度及原初能谱“膝”的研究

用梁王山宇宙线观测站的数据研究宇宙线大气簇射μ子定点密度谱,谱呈现明显的拐折.通过MonteCarlo模拟,得到拐点对应的能量约为1.7×10¹⁵eV,拐点前后原初能谱指数差约为0.43,证实了KASCADE实验μ子定点密度谱呈现拐折的首次观测结果,又一次推证了原初宇宙线能谱膝的存在.     

A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the determination of phenolic polycyclic aromatic hydrocarbons (OH-PAH) in urine of non-smokers and smokers

Polycyclic aromatic hydrocarbons (PAH) are products of the incomplete combustion of organic materials and, therefore, occur ubiquitously in the environment and also in tobacco smoke. Since some PAH have been classified as carcinogens, it is important to have access to suitable analytical methods for biomarkers of exposure to this class of compounds. Past experience has shown that measuring a profile of PAH metabolites is more informative than metabolites of a single PAH. Assessment of environmental and smoking-related exposure levels requires analytical methods with high sensitivity and specificity. In addition, these methods should be fast enough to allow high throughput. With these pre-conditions in mind, we developed and validated a high-performance liquid chromatographic method with tandem mass spectrometric detection (LC-MS/MS) for the determination of phenolic metabolites of naphthalene, fluorene, phenanthrene and pyrene in urine of smokers and non-smokers. Sample work-up comprised enzymatic hydrolysis of urinary conjugates and solid-phase extraction on C18 cartridges. The method showed good specificity, sensitivity, and accuracy for the intended purpose and was also sufficiently rapid with a sample throughput of about 350 per week. Application to urine samples of 100 smokers and 50 non-smokers showed significant differences between both groups for all measured PAH metabolites, and strong correlations with markers of daily smoke exposure in smoker urine. Urinary levels were in good agreement with previously reported data using different methodologies. In conclusion, the developed LC-MS/MS method is suitable for the quantification of phenolic PAH metabolites of naphthalene, fluorene, phenanthrene, and pyrene in smoker and non-smoker urine.     

Radial Blaschke–Minkowski homomorphisms and volume differences

In this paper we establish Minkowski, Brunn–Minkowski, and Aleksandrov-Fenchel type inequalities for volume differences of radial Blaschke–Minkowski homomorphisms.     

(3h)J((15)N-(31)P) spin-spin coupling constants across N[bond]H....O[bond]P hydrogen bonds

Equation-of-motion coupled cluster singles and doubles (EOM-CCSD) calculations have been performed to evaluate three-bond (15)N-(31)P coupling constants ((3h)J(N[bond]P)) across N[bond]H....O[bond]P hydrogen bonds in model cationic and anionic complexes including NH(4)(+):OPH, NH(4)(+):OPH(3), NH(3):(-)O(2)PH(2), NFH(2):(-)O(2)PH(2), and NF(2)H:(-)O(2)PH(2). Three-bond coupling constants can be appreciable when the phosphorus is P(V), but are negligible with P(III). (3h)J(N[bond]P) values in complexes with cyclic or open structures are less than 1 Hz, a consequence of the nonlinear arrangement of N, H, O, and P atoms. For complexes with these structures, (3h)J(N[bond]P) may not be experimentally measurable. In contrast, complexes in which the N, H, O, and P atoms are collinear or nearly collinear have larger values of (3h)J(N[bond]P), even though the N[bond]P distances are longer than N[bond]P distances in cyclic and open structures. In linear complexes, (3h)J(N[bond]P) is dominated by the Fermi-contact term, which is distance dependent. Therefore, N[bond]P (and hydrogen-bonding N[bond]O) distances in these complexes can be determined from experimentally measured (15)N-(31)P coupling constants.