Modified projection method for strongly pseudomonotone variational inequalities

A modified projection method for strongly pseudomonotone variational inequalities is considered. Strong convergence and error estimates for the sequences generated by this method are studied in two versions of the method: the stepsizes are chosen arbitrarily from a given fixed closed interval and the stepsizes form a non-summable decreasing sequence of positive real numbers. We also propose some interesting examples to analyze the obtained results.     

Shape Gradient for Isogeometric Structural Design

The transfer of geometrical data from CAD (Computer Aided Design) to FEA (Finite-Element Analysis) is a bottleneck of automated design optimization procedures, yielding a loss of accuracy and cumbersome software couplings. Isogeometric analysis methods propose a new paradigm that allows one to overcome these difficulties by using a unique geometrical representation, yielding a direct relationship between geometry and analysis. In this study, in the framework of linear elasticity problems, we investigate its use for sensitivity analysis and, more specifically, shape gradient computations.     

Visible-Light-Enabled Direct Decarboxylative N-Alkylation

The development of efficient and selective C−N bond-forming reactions from abundant feedstock chemicals remains a central theme in organic chemistry owing to the key roles of amines in synthesis, drug discovery, and materials science. Herein, we present a dual catalytic system for the N-alkylation of diverse aromatic carbocyclic and heterocyclic amines directly with carboxylic acids, by-passing their preactivation as redox-active esters. The reaction, which is enabled by visible-light-driven, acridine-catalyzed decarboxylation, provides access to N-alkylated secondary and tertiary anilines and N-heterocycles. Additional examples, including double alkylation, the installation of metabolically robust deuterated methyl groups, and tandem ring formation, further demonstrate the potential of the direct decarboxylative alkylation (DDA) reaction.     

Heterogeneity and increasing returns may drive socio-economic transitions

There are clear benefits associated with a particular consumer choice for many current markets. For example, as we consider here, some products might carry environmental or ‘green’ benefits. Some consumers might value these benefits while others do not. However, as evidenced by myriad failed attempts of environmental products to maintain even a niche market, such benefits do not necessarily outweigh the extra purchasing cost. The question we pose is, how can such an initially economically-disadvantaged green product evolve to hold the greater share of the market? We present a simple mathematical model for the dynamics of product competition in a heterogeneous consumer population. Our model preassigns a hierarchy to the products, which designates the consumer choice when prices are comparable, while prices are dynamically rescaled to reflect increasing returns to scale. Our approach allows us to model many scenarios of technology substitution and provides a method for generalizing market forces. With this model, we begin to forecast irreversible trends associated with consumer dynamics as well as policies that could be made to influence transitions.     

Characterization of cationic copolymers by capillary electrophoresis using indirect UV detection and contactless conductivity detection

For many industrial applications, the combination of two different monomers in statistical or diblock copolymers enhances the properties of the corresponding polymer. However, during the polymerization reaction, homopolymers might be formed and can influence the properties for the applications. Consequently, the separation and the quantification of the homopolymers contained in copolymer samples are crucial. In addition, the charge density distribution of the statistical copolymer is an important characteristic for the applications. The purpose of this work was to study the characterization of a statistical copolymer of acrylic acid (AA) and diallyldimethyl ammonium chloride (DADMAC) by capillary electrophoresis (CE) in acidic conditions (cationic copolymers). For that purpose, a free solution electrophoretic separation was carried out according to the charge rate (chemical composition) independently of the molar mass. The second objective was to compare contactless conductivity detection and indirect UV absorbance modes for the quantification of DADMAC homopolymers present in copolymer samples. Different coated capillaries based on neutral or positively charged modification were also compared. The comparison of indirect absorbance UV and contactless conductimetric detection demonstrated that both detection modes can be used for a complete CE characterization of non-UV absorbing PAA-DADMAC copolymers.     

Manganese alkane complexes: an IR and NMR spectroscopic investigation

Manganese propane and manganese butane complexes derived from CpMn(CO)(3) were generated photochemically at 130-136 K with the alkane as solvent and characterized by FTIR spectroscopy and by (1)H NMR spectroscopy with in situ laser photolysis. Time-resolved IR spectroscopic measurements were performed at room temperature with the same laser wavelength. The ν(CO) bands in the IR spectra of the photoproducts in propane are shifted to low frequency with respect to CpMn(CO)(3), consistent with formation of CpMn(CO)(2)(propane). The (1)H NMR spectra conform to the criteria for alkane complexes: a high-field resonance for the η(2)-CH protons that shifts substantially on partial deuteration of the alkane and exhibits a coupling constant J(C-H) on (13)C-labeling of ca. 120 Hz. The NMR spectrum of each system exhibits two diagnostic product resonances in the high-field region for the η(2)-CH protons, corresponding to CpMn(CO)(2)(η(2)-C1-H-alkane) and CpMn(CO)(2)(η(2)-C2-H-alkane) isomers. Partial deuteration of the alkane at C1 results in characteristic strong isotopic perturbation of equilibrium of the η(2)-CH resonance of CpMn(CO)(2)(η(2)-C1-H-alkane). With propane-(13)C(1), the η(2)-CH resonance of CpMn(CO)(2)(η(2)-C1-H-alkane) isomer exhibits (13)C satellites with J(C-H) = 119 Hz. The corresponding resonance of CpMn(CO)(2)(η(2)-C2-H-alkane) is identified by use of propane-2,2-d(2). The lifetimes of the (η(2)-C1-H-alkane) isomers of the manganese complexes were determined by NMR spectroscopy as 22 ± 2 min at 134 K (propane) and 5.5 min at 136 K (butane). The corresponding spectra and lifetimes of the CpRe(CO)(2)(alkane) complexes were measured for reference (CpRe(CO)(2)(propane) lifetime ca. 60 min at 161 K; CpRe(CO)(2)(butane) 13 min at 171 K). The lifetimes determined by IR spectroscopy were similar to those determined by NMR spectroscopy, thereby supporting the assignments. These measurements extend the range of alkane complexes characterized by NMR spectroscopy from rhenium and rhodium derivatives to include less stable manganese derivatives.     

Investigation of thermal treatment of hybrid nanoparticles in a domain with different permeabilities

Journal of Thermal Analysis and Calorimetry - Porous domain filled with nanoliquid was scrutinized in the current article. Magnetic force and permeability were considered as main effective...     

Formal synthesis of TMC-69-6H via a one-pot enantioselective domino proline-mediated aldol/olefin homologation procedure

Enantioselective synthesis of TMC-69-6H was accomplished from readily accessible pyridone derivative via a domino proline-mediated aldol reaction/olefin homologation, followed by tandem ring-closing and cross metathesis.     

Synthesis of Gb3 Glycosphingolipids with Labeled Head Groups: Distribution in Phase‐Separated Giant Unilamellar Vesicles

The receptor lipid Gb₃ is responsible for the specific internalization of Shiga toxin (STx) into cells. The head group of Gb₃ defines the specificity of STx binding, and the backbone with different fatty acids is expected to influence its localization within membranes impacting membrane organization and protein internalization. To investigate this influence, a set of Gb₃ glycosphingolipids labeled with a BODIPY fluorophore attached to the head group was synthesized. C₂₄ fatty acids, saturated, unsaturated, α‐hydroxylated derivatives, and a combination thereof, were attached to the sphingosine backbone. The synthetic Gb₃ glycosphingolipids were reconstituted into coexisting liquid‐ordered (l_o)/liquid‐disordered (l_d) giant unilamellar vesicles (GUVs), and STx binding was verified by fluorescence microscopy. Gb₃ with the C_24:0 fatty acid partitioned mostly in the l_o phase, while the unsaturated C_24:1 fatty acid distributes more into the l_d phase. The α‐hydroxylation does not influence its partitioning.