One-dimensional stock cutting: optimization of usable leftovers in consecutive orders

Central European Journal of Operations Research - This paper deals with usable leftovers (UL) in one-dimensional stock cutting in consecutive orders. UL are leftovers longer than a certain...     

A generalized additive, categorical model in data envelopment analysis

This paper considers efficiency of a Decision Making Unit (DMU) in Data Envelopment Analysis (DEA) with a generalized additive model and a categorical structure. Specifically, it extends the categorical framework in DEA for controllable and noncontrollable situations, and it gives simple, but powerful, tests to determine whether or not a given DMU is efficient.     

Optimal taxation of a perfectly competitive firm with Cobb–Douglas production function as a bilevel programming problem

Central European Journal of Operations Research - Taxation is one of the most powerful instruments of fiscal policy, affecting economic growth and investments, as well as competitiveness of...     

O‐Doped Nanographenes: A Pyrano/Pyrylium Route Towards Semiconducting Cationic Mixed‐Valence Complexes

Herein we report an efficient synthesis to prepare O‐doped nanographenes derived from the π‐extension of pyrene. The derivatives are highly fluorescent and feature low oxidation potentials. Using electrooxidation, crystals of cationic mixed‐valence (MV) complexes were grown in which the organic salts organize into face‐to‐face π‐stacks, a favorable solid‐state arrangement for organic electronics. Variable‐temperature electron paramagnetic resonance (EPR) measurements and relaxation studies suggest a strong electron delocalization along the longitudinal axis of the columnar π‐stacking architectures. Electric measurements of single crystals of the MV salts show a semiconducting behavior with a remarkably high conductivity at room temperature. These findings support the notion that π‐extension of heteroatom‐doped polycyclic aromatic hydrocarbons is an attractive approach to fabricate nanographenes with a broad spectrum of semiconducting properties and high charge mobilities.     

Heterocyclic Chromophore Amphiphiles and their Supramolecular Polymerization

Supramolecular polymerization of π-conjugated amphiphiles in water is an attractive approach to create functional nanostructures. Here, we report on the synthesis, optoelectronic and electrochemical properties, aqueous supramolecular polymerization, and conductivity of polycyclic aromatic dicarboximide amphiphiles. The chemical structure of the model perylene monoimide amphiphile was modified with heterocycles, essentially substituting one fused benzene ring with thiophene, pyridine or pyrrole rings. All the heterocycle-containing monomers investigated underwent supramolecular polymerization in water. Large changes to the monomeric molecular dipole moments led to nanostructures with low electrical conductivity due to diminished interactions. Although the substitution of benzene with thiophene did not notably change the monomer dipole moment, it led to crystalline nanoribbons with 20-fold higher electrical conductivity, due to enhanced dispersion interactions as a result of the presence of sulfur atoms.     

Targeting Antibiotic Resistance

Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human‐pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even last‐resort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled “Combat drug resistance: no action today means no cure tomorrow” triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens.     

Synthesis,Separation, and Characterization of Small and Highly Fluorescent Nitrogen‐Doped Carbon NanoDots

A facile bottom‐up approach to carbon nanodots (CNDs) is reported, using a microwave‐assisted procedure under controlled conditions. The as‐prepared nitrogen‐doped CNDs (NCNDs) show narrow size‐distribution, abundant surface traps and functional groups, resulting in tunable fluorescent emission and excellent solubility in water. Moreover, we present a general method for the separation of NCNDs by low‐pressure size‐exclusion chromatography, leading to an even narrower size distribution, different surface composition, and optical properties. They display among the smallest size and the highest FLQYs reported so far. ¹³C‐enriched starting materials produced N¹³CNDs suitable for thorough NMR studies, which gave useful information on their molecular structure. Moreover, they can be easily functionalized and can be used as water‐soluble carriers. This work provides an avenue to size‐ and surface‐controllable and structurally defined NCNDs for applications in areas such as optoelectronics, biomedicine, and bioimaging.