Inverse closed ultradifferential subalgebras

In previous work we have shown that classical approximation theory provides methods for the systematic construction of inverse-closed smooth subalgebras. Now we extend this work to treat inverse-closed subalgebras of ultradifferentiable elements. In particular, Carleman classes and Dales–Davie algebras are treated. As an application the result of Demko, Smith and Moss, and Jaffard on the inverse of a matrix with exponential decay is obtained within the framework of a general theory of smoothness.     

Triostin A Derived Cyclopeptide as Architectural Template for the Alignment of Four Recognition Units

The DNA bisintercalator triostin A is structurally based on a disulfide-bridged depsipeptide scaffold that provides preorganization of two quinoxaline units in 10.5 Å distance. Triostin A analogues are synthesized with nucleobase recognition units replacing the quinoxalines and containing two additional recognition units in between. Thus, four nucleobase recognition units are organized on a rigid template, well suited for DNA double strand interactions. The new tetra-nucleobase binders are synthesized as aza-TANDEM derivatives lacking the N-methylation of triostin A and based on a cyclopeptide backbone. Synthesis of two tetra-nucleobase aza-TANDEM derivatives is established, DNA interaction analyzed by microscale thermophoresis, cytotoxic activity studied and a nucleobase sequence dependent self-aggregation investigated by mass spectrometry.     

Thioetherphenolate group 4 metal complexes in the ring opening polymerization of rac‐β‐Butyrolactone

Group 4 complexes 1 – 3 [ 1 = (t‐BuOS)₂Ti(O‐i‐Pr)₂; 2 = (t‐BuOS)₂Zr(O‐t‐Bu)₂; 3 = (t‐BuOS)₂Hf(O‐t‐Bu)₂] supported by two phenolate bidentate ligands (t‐BuOS‐H = 4,6‐di‐tert‐butyl‐2‐phenylsulfanylphenol) promote the well‐controlled ring opening polymerization of rac‐β‐butyrolactone. In presence of isopropanol, low dispersities and molecular weights proportional to the equivalents of isopropanol are achieved. Moreover, the zirconium complex is effective in the copolymerization of rac‐β‐butyrolactone with rac‐lactide. The 13 C nuclear magnetic resonance analysis revealed that the obtained copolymers have a tapered diblock microstructure consisting of an initial block composed of lactide sequences and a terminal block composed of butyrolactone sequences. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3132–3139     

Synthesis of 4-unsubstituted 2H-1,2,3-benzothiadiazine 1,1-dioxides via ortho lithiation of protected benzaldehyde derivatives

Variously substituted 2-phenyl-1,3-dioxolanes and 2-(2-bromophenyl)-1,3-dioxolanes, prepared from the corresponding benzaldehydes, were lithiated ortho to the acetal group. Reaction of the lithio derivatives with sulfur dioxide led to the lithium sulfinate salts, which gave, upon oxidative chlorination with sulfuryl chloride, the corresponding benzenesulfonyl chlorides. Then, depending on the aromatic substitution pattern of the molecule, several protocols were elaborated for the functional group transformations leading to the target compounds. Ring closure was performed with hydrazine hydrate or acetylhydrazine, in the latter case with one-pot removal of the acetyl group. The 4-unsubstituted 2H-1,2,3-benzothiadiazine 1,1-dioxides thus obtained are potential drug candidates based on their structural similarity to biologically active phthalazinones.     

Differential 3D shape retrieval

We are presenting a differential three-dimensional (3-D) shape profiling method that is based on the combination of orthogonal fringe projection. It allows us to compute depth gradient maps in a fast and efficient manner. What we are demonstrating is that depth gradients can be computed in a simple way by measuring fringe deformation throughout a novel single-shot approach. We show the usefulness and potential applications of the proposed approach. Validation experiments are presented as well.     

New application of human eye model in the verification of spot diagram with refractive diopter

In response to the rapid advancement of auto-refractor technology, most optometry shops provide refraction services. Despite their speed and convenience, the measurement values provided by auto-refractors include a significant degree of error due to psychological and physical factors. Therefore, there is a need for repetitive testing to obtain a smaller mean error value. However, even repetitive testing itself might not be sufficient to ensure accurate measurements. Therefore, research on a method of measurement that can complement auto-refractor measurements and provide confirmation of refraction results needs to be conducted. The customized optometry model described herein can satisfy the above requirements. From the existing optical technologies, using human eye measurement devices to obtain individual relevant optical feature parameters is no longer difficult. These parameters allow us to construct an optometry model for individual eyeballs. They also allow us to compute spot diagrams produced from the optometry model using the CODE V macro programming language before recognizing the geometrical spot diagram with the back-propagation neural network algorithm to obtain the accurate refractive diopter. Results show that the accuracy achieved was above 98% and that this application could significantly enhance the service quality of refraction.     

The Synthesis of B2(SIDip)2 and its Reactivity Between the Diboracumulenic and Diborynic Extremes

A new compound with the formula L‐B₂‐L wherein the stabilizing ligand (L) is 1,3‐bis[diisopropylphenyl]‐4,5‐dihydroimidazol‐2‐ylidene (SIDip) has been synthesized, isolated, and characterized. The π‐acidity of the SIDip ligand, intermediate between the relatively non‐acidic IDip (1,3‐bis[diisopropylphenyl]imidazol‐2‐ylidene) ligand and the much more highly acidic CAAC (1‐[2,6‐diisopropylphenyl]‐3,3,5,5‐tetramethylpyrrolidin‐2‐ylidene) ligand, gives rise to a compound with spectroscopic, electrochemical, and structural properties between those of L‐B₂‐L compounds stabilized by CAAC and IDip. Reactions of all three L‐B₂‐L compounds with CO demonstrate the differences caused by their respective ligands, as the π‐acidities of the CAAC and SIDip carbenes enabled the isolation of bis(boraketene) compounds (L(OC)B‐B(CO)L), which could not be isolated from reactions with B₂(IDip)₂. However, only B₂(IDip)₂ and B₂(SIDip)₂ could be converted into bicyclic bis(boralactone) compounds.     

Methoxy and Methyl Group Rotation: Solid‐State NMR 1H Spin‐Lattice Relaxation,Electronic Structure Calculations,X‐ray Diffractometry,and Scanning Electron Microscopy

We report solid‐state ¹H nuclear magnetic resonance (NMR) spin‐lattice relaxation experiments, X‐ray diffractometry, field‐emission scanning electron microscopy, and both single‐molecule and cluster ab initio electronic structure calculations on 1‐methoxyphenanthrene ( 1 ) and 3‐methoxyphenanthrene ( 2 ) to investigate the rotation of the methoxy groups and their constituent methyl groups. The electronic structure calculations and the ¹H NMR relaxation measurements can be used together to determine barriers for the rotation of a methoxy group and its constituent methyl group and to develop models for the two coupled motions.