Palladium‐ and Solvent‐Free Synthesis of Ynones by Copper(I)‐Catalyzed Acylation of Terminal Alkynes with Acyl Chlorides under Aerobic Conditions

Air‐stable Cu^I/cryptand‐22 complex was found to be a highly active catalyst for the solvent‐free cross‐coupling reaction of terminal alkynes with different acyl chlorides in the presence of Et₃N as base to give the corresponding ynones in quantitative yields.     

Bayesian semiparametric analysis for a single item maintenance optimization

We address the problem of a finite horizon single item maintenance optimization structured as a combination of preventive and corrective maintenance in a nuclear power plant environment. We present Bayesian semiparametric models to estimate the failure time distribution and costs involved. The objective function for the optimization is the expected total cost of maintenance over the pre-defined finite time horizon. Typically, the mathematical modeling of failure times are based on parametric models. These models fail to capture the true underlying relationships in the data; indeed, under a parametric assumption, the hazard rates are treated as unimodal, which, as shown in this paper, is incorrect. Importantly, assuming an increasing failure rate, as is typically done, we show, is way off the mark in the present context. Since hazard and cost estimates feed into the optimization phase, from a risk management perspective, potentially gross errors, resulting from purely parametric models, can be obviated. We show the effectiveness of our approach using real data from the South Texas Project Nuclear Operating Company (STPNOC) located in Bay City, Texas.     

Ag(I)配位聚合物[Ag2(bpp)2(H2O)]·pydc·7H2O的合成、表征及性质研究

水热合成了基于吡啶-3,5-二羧酸(H2pydc)的含Ag(I)配位聚合物 [Ag2(bpp)2(H2O)]·pydc·7H2O (1) (其中bpp = 1,3-双(4-吡啶)丙烷)。X射线单晶结构分析表明,在一维化合物1中,发现了包含(H2O)12水簇单元的二维氢键层状结构。有趣的是,在该二维层中, 每个pydc2-阴离子作为“桥”连接了两个(H2O)12单元和两个自由水分子。另外,对化合物1的荧光、热重、粉末衍射等也进行了研究和讨论。     

A method of solving a nonlinear boundary value problem with a parameter for a loaded differential equation

A nonlinear loaded differential equation with a parameter on a finite interval is studied. The interval is partitioned by the load points, at which the values of the solution to the equation are set as additional parameters. A nonlinear boundary value problem for the considered equation is reduced to a nonlinear multipoint boundary value problem for the system of nonlinear ordinary differential equations with parameters. For fixed parameters, we obtain the Cauchy problems for ordinary differential equations on the subintervals. Substituting the values of the solutions to these problems into the boundary condition and continuity conditions at the partition points, we compose a system of nonlinear algebraic equations in parameters. A method of solving the boundary value problem with a parameter is proposed. The method is based on finding the solution to the system of nonlinear algebraic equations composed.     

Catalyst-free green synthesis of tetrahydro-benzo[b]pyrans in magnetized water: experimental aspects and molecular dynamics simulation

Research on Chemical Intermediates - In this work, magnetized water is applied as a green-promoting medium for the catalyst-free, one-pot, practical, efficient, and environmentally benign...     

Ti Impurity Effect on the Optical Coefficients in 2D Cu_2Si: A DFT Study

The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256μB magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu_2Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu_2Si:Ti.     

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.     

Synthesis of new dihybrid nanofluid of TiO2/MWCNT in water–ethylene glycol to improve mixture thermal performance: preparation,characterization, and a novel correlation via ANN based on orthogonal distance regression algorithm

Journal of Thermal Analysis and Calorimetry - Nanofluid refers to the mixture of fluid and solid nanoparticles. If this mixture contains more than one NP or fluid, it is called “hybrid...     

Network deployment of radiation detectors with?physics-based detection probability calculations

We describe a model for deploying radiation detectors on a transportation network consisting of two adversaries: a nuclear-material smuggler and an interdictor. The interdictor first installs the detectors. These installations are transparent to the smuggler, and are made under an uncertain threat scenario, which specifies the smuggler??s origin and destination, the nature of the material being smuggled, the manner in which it is shielded, and the mechanism by which the smuggler selects a route. The interdictor??s goal is to minimize the probability the smuggler evades detection. The performance of the detection equipment depends on the material being sensed, geometric attenuation, shielding, cargo and container type, background, time allotted for sensing and a number of other factors. Using a stochastic radiation transport code (MCNPX), we estimate detection probabilities for a specific set of such parameters, and inform the interdiction model with these estimates.