nBu(4)NI-catalyzed C3-selective formylation of N-H and N-substituted indoles by using N-methylaniline as a formylating reagent was first successfully demonstrated.

New alkaline-earth amido complexes catalyze the regioselective intermolecular hydroamination (see scheme; Ae=alkaline earth) and hydrophosphination of styrene and isoprene with unprecedented activities. The catalytic performances increased linearly with the size of the metal.

A profound way to increase the output voltage (or power) of the piezoelectric nanogenerators is to utilize a material with higher piezoelectric constants. Here we report the synthesis of novel piezoelectric 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) nanowires using a hydrothermal process. The un-poled single-crystal PMN-PT nanowires show a piezoelectric constant (d33) up to ...

A new hemiketal eunicellin-based diterpenoid, cladieunicellin H (1), was isolated from an Indonesian octocoral identified as Cladiella sp. The structure of 1 was determined by spectroscopic methods. This compound was found to display moderate inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils.

A new germacrane-type sesquiterpenoid, menelloide E (1), and a new cembrane-type diterpenoid, lobocrassin F (2), were isolated from the octocorals Menella sp. and Lobophytum crassum, respectively. The structures of terpenoids 1 and 2 were determined by spectroscopic and chemical methods and compound 2 was found to display a significant inhibitory ...

Hidden treasure: Gold nanoparticles (AuNPs) within a single protein crystal of lysozyme (see scheme, pink) are shown to efficiently catalyze the reduction of p-nitrophenol by NaBH(4) , and the catalytic activity initially increased with increased size of AuNPs until the size reached 7.4 nm, after which the activity decreased with increasing ...

The elastic deformation of few layers (5 to 25) of thick, freely suspended MoS(2) nanosheets by means of a nanoscopic version of a bending test experiment, carried out with the tip of an atomic force microscope is reported. Young's modulus of these nanosheets is extremely high (E = 0.33 TPa), ...

Herein we introduce a novel strategy based on capillary force lithography (CFL) to fabricate asymmetric polymeric ring structures by applying both shear and nomal forces to a poly(dimethylsiloxane) stamp. The mechanism for the formation of asymmetric rings is caused by the deflection of cylindrical PDMS pillars due to the shear ...

From determining the optical properties of simple molecular crystals to establishing the preferred handedness in highly complex vertebrates, molecular chirality profoundly influences the structural, mechanical and optical properties of both synthetic and biological matter on macroscopic length scales. In soft materials such as amphiphilic lipids and liquid crystals, the competition ...

By mediating the tethering and rolling of leukocytes on vascular surfaces, the interactions between P-selectin and the P-selectin glycoprotein ligand 1 (PSGL-1) play crucial roles during inflammation cascade. Tensile stretch produced by rolling leukocytes and shear stress exerted by blood flow constitute the two types of mechanical forces that act ...

A nearly exact general equation for geometrical angular deviations from the Bragg angle over entire curved crystal surfaces is derived using a toroidally curvilinear coordinate system and applied on the nine conventional crystal geometries. Although the derived formula confirms Wittry's results for the first five cases, it shows considerable differences ...

The endo trick: An endo ring closure onto the trigonal β carbon atom of α,β-unsaturated acceptors that are tethered to the indole nitrogen atom followed by amide cleavage enables the diastereoselective C-2 alkenylation of indoles with fully substituted double bonds. The carboxy group functions as a synthetically useful temporary tether.

In this paper, a new nanostructure is proposed, namely, the knitted graphene-nanoribbon sheet (KGS), which consists of zigzag and/or armchair graphene nanoribbons. The knitting technology is introduced to graphene nanotechnology to produce large area graphene sheets. Compared with pristine graphene, the chirality of a knitted graphene-nanoribbon sheet is much more ...

PURPOSE: To investigate the influence of primary crystallization conditions on the mechanical properties and secondary processing behaviour of fluticasone propionate (FP) for carrier based dry powder inhaler (DPI) formulations. METHODS: Young's modulus of FP crystals produced using different anti-solvents was determined using nanoindentation. Physicochemical and surface interfacial properties via the ...

The dimeric self-assembly program of a new, multidentate ligand with cuprous ions overcomes crystal packing forces, which leads to C(i) symmetry in the solid state, to form a no less than partially C(2)-symmetric structure in solution. The resulting tetranitro-substituted dicopper(i) metallocyclophane displays an exceptionally strong second harmonic frequency response (β ...

Molecular dynamics simulations have been performed to study the potential of mean force (PMF) between passivated gold nanoparticles (NPs) in supercritical CO(2) (scCO(2)). The nanoparticle model consists of a 140 atom gold nanocore and a surface self-assembled monolayer, in which two kinds of fluorinated alkanethiols were considered. The molecular origin ...

Amontons' law successfully describes friction between macroscopic solid bodies for a wide range of velocities and normal forces. For the diffusion and forced sliding of adhering or entangled macromolecules, proteins and biological complexes, temperature effects are invariably important and a similarly successful friction law at biological length and velocity scales ...

Atomic Force Microscopy-based single molecule force spectroscopy (AFM-SMFS) was used to study the forced unbinding of quadruple self-complementary hydrogen-bonded urea-aminotriazine (UAT) complexes in hexadecane (HD). To elucidate the bond strength of individual linkeages, the unbinding forces of UAT supramolecular polymers were investigated for the first time. The bond rupture was ...

In the title compound, C(26)H(24), the central cyclo-octa-tetra-ene ring has a boat conformation, and the mol-ecule is saddle shaped. The seat is defined by the mean plane of the four-atom attachment points (r.m.s. deviation = 0.014 Å) of the two bicyclo-heptane substituents. These substituents comprise the pommel and cantle, with each ...

We have performed a detailed study of the lattice distortions of InP wurtzite nanowires containing an axial screw dislocation. Eshelby predicted that this kind of system should show a crystal rotation due to the dislocation induced torque. We have measured the twisting rate and the dislocation Burgers vector on individual ...

Ice crystal growth experiments in heavy water were carried out under microgravity to investigate the morphological transition from a disk crystal to a dendrite. Surprisingly, however, no transition was observed, namely, the disk crystal or dendrite maintained its shape throughout the experiments, unlike the results obtained on the ground. Therefore, ...

The complete mol-ecule of the title compound, C(26)H(38)N(2), is generated by a crystallographic inversion centre. The piperazine ring adopts a chair conformation with pseudo-equatorial substituents. In the crystal, mol-ecules inter-act only by van der Waals forces.

The non-H atoms of the title compound, C(16)H(12)O(3), lie approximately in a common plane (r.m.s. deviation = 0.032 Å). The methyl C atom is forced away from the carbonyl O atom which can be seen by the widened C(fused ring)-C(benzene)-C(meth-yl) angle of 125.8 (2)°.

Using theory of harmonic normal-mode vibration analysis, we developed a procedure for evaluating the anisotropic stiffness of intermolecular forces. Our scheme for coarse-graining of molecular motions is modified so as to account for intramolecular vibrations in addition to relative translational∕rotational displacement. We applied this new analytical scheme to four carboxylic ...

Surface-immobilized and switchable resorcin[4]arene receptor molecules were quantitatively investigated with atomic force microscopy (AFM) and AFM-single molecule force spectroscopy (AFM-SMFS). The upper rim of the supramolecular receptor cavities was modified with two photodimerizable anthracene moieties. The molecular constitution can be externally switched and controlled by exposure to ultraviolet (UV) light ...

In the solid state the title Schiff base, 0.58C(28)H(20)N(2)O(2)·0.42C(28)H(20)N(2)O(2), exists both as the keto-imino and as the enol-amino tautomer, which is manifested in the disorder of the H atom in the intra-molecular hydrogen-bonded ring. The naphthalene ring systems show some distortion, which is consistent with the quinoid effect. The ratio ...

Context: Caffeine/oxalic acid 2:1 cocrystal exhibited superior stability to humidity over caffeine, but compressional behavior is not studied yet. Objective: To compare compressional properties of caffeine/oxalic acid 2:1 cocrystal obtained by different cocrystallization techniques. Materials and methods: Cocrystal was obtained by solvent precipitation and ultrasound assisted solution cocrystallization (USSC) and ...

Abstract Objectives: To compare forces versus failure and shear bond strengths, and to explore their association with the base dimensions of four currently available bondable molar tubes. Materials and Methods: Tubes were bonded to hydroxyapatite discs using a conventional light-cured adhesive and were tested to shear failure with the Instron ...

We consider the theory of fluctuations of a colloidal solid observed in a confocal slice. For a cubic crystal we study the evolution of the projected elastic properties as a function of the anisotropy of the crystal using numerical methods based on the fast Fourier transform. In certain situations of ...

Given a closed Riemannian manifold (M, g), i.e. compact and boundaryless, there is a partition of its tangent bundle TM = ∪iΣi called the focal decomposition of TM. The sets Σi are closely associated to focusing of geodesics of (M, g), i.e. to the situation where there are exactly i ...

Crystallization and vitrification of tetrahedral liquids are important both from a fundamental and a technological point of view. Here, we study via extensive umbrella sampling Monte Carlo computer simulations the nucleation barriers for a simple model for tetrahedral patchy particles in the regime where open tetrahedral crystal structures (namely, cubic ...

Phenomena such as shear thinning and thickening, occurring when complex materials are exposed to external forces, are generally believed to be closely connected to changes in the microstructure. Here, we establish a direct and quantitative relation between shear thinning in a colloidal crystal and the surface area of the locally ...

Steric effects in chemistry are a consequence of the space required to accommodate the atoms and groups within a molecule, and are often thought to be dominated by repulsive forces arising from overlapping electron densities (Pauli repulsion). An appreciation of attractive interactions such as van der Waals forces (which include ...

An in situ tensile-shear loading device has been designed to study elastomer crystallization using synchrotron X-ray scattering at the Synchrotron Soleil on the DiffAbs beamline. Elastomer tape specimens of thickness 2 mm can be elongated by up to 500% in the longitudinal direction and sheared by up to 200% in the ...

Ideal shear strength under superimposed normal stress of cubic covalent crystals (C, Si, Ge, and SiC) is evaluated by ab initio density functional theory calculation. Shear directions in [[Formula: see text]] and [[Formula: see text]] on the (111) plane are examined. The critical shear stress along the former direction is ...

In the title Schiff base mol-ecule, C(13)H(9)BrClN, the dihedral angle between the benzene rings is 49.8 (2)° and the mol-ecule has an E configuration about the C=N bond. In the crystal, there are no directional interactions but only van der Waals inter-molecular inter-action forces between neighbouring mol-ecules.

Abstract Objective: To test the manufacturer's recommendation for the application rubbing time of a self-etching primer (Transbond Plus, 3M Unitek) and to compare the resulting bond strength of a resin composite (Transbond XT, 3M Unitek) in the traditional laboratory tension on all four wings with a simulation of the clinical ...

Much of modern technology--from data encryption to environmental sensors to templates for device fabrication--relies on encoding complex chemical information in a single material platform. Here we develop a technique for patterning multiple chemical functionalities throughout the inner surfaces of three-dimensional (3D) porous structures. Using a highly ordered 3D photonic crystal ...

Abstract: A new method is presented to describe deformations of an N-membered planar ring (N-ring) molecule in terms of deformation vectors that can be expressed by a set of 2N-3 deformation amplitudes and phase angles. The deformation coordinates are directly derived from the normal vibrational modes of the N-ring and ...

In this work, the mechanical properties of C60 molecules adsorbed on Cu(111) are measured by tuning fork based non contact atomic force microscopy (nc-AFM) and spectroscopy at cryogenic conditions. Site-specific tip-sample stiffnesses are detected above the buckyball structure. Moreover, high-resolution images obtained by nc-AFM show the chemical structure of this ...

Receptor-ligand interactions that mediate cellular adhesion are often subjected to forces that regulate their detachment via modulating off-rates. Although the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules, cellular features such as cell deformability and microvillus viscoelasticity have been shown to affect the rolling velocity ...

This report addresses the development of experimental and computational estimations of the anisotropic elastic moduli (EM) of single crystals to aid in the a priori (i.e., starting with the crystal structure) prediction of the trend as a function of the direction of applied stress. Experimentally EM values in the normal ...

A new concept for dealing with cracks in colloidal crystals has been proposed. We induce the cracks rather than eliminate them via templates that possess hydrophilic/hydrophobic patterns on the surface (surface energy patterns), leading the cracks to propagate along the predetermined lines. Colloidal crystal arrays with various kinds of element ...

We demonstrate that well prepared and characterized Cr tips can provide atomic resolution on the bulk NaCl(001) surface with dynamic atomic force microscopy in the noncontact regime at relatively large tip-sample separations. At these conditions, the surface chemical structure can be resolved yet tip-surface instabilities are absent. Our calculations demonstrate ...

A DNA dodecamer and the methyladenine...methylthymine (mA...mT) complex in aqueous environment have been studied by means of molecular dynamics simulation, with a modified force field accounting for the hypothetical absence of London dispersion forces. Under these conditions, the mA...mT complex is preserved, while the double-helical DNA oligomer passes via an ...

Sophisticated molecular machines have evolved in nature, and the first synthetic molecular machines have been demonstrated. With our increasing understanding of individual operating cycles, the question of how operation can be sustained over many cycles comes to the forefront. In the design of macroscale machines, performance and lifetime are opposing ...

We report on high-resolution friction force microscopy on a stepped NaCl(001) surface in ultrahigh vacuum. The measurements were performed on single cleavage step edges. When blunt tips are used, friction is found to increase while scanning both up and down a step edge. With atomically sharp tips, friction still increases ...

In the title mol-ecule, [Fe(C(5)H(5))(C(18)H(17)Si)], the distances of the Fe atom from the centroids of the unsubstituted and substituted cyclo-penta-dienyl (Cp) rings are 1.651 (1) and 1.646 (1) Å, respectively. The dihedral angle between the two Cp rings is 3.20 (17)°. The crystal packing is mainly stabilized by van der Waals forces.

Side-chain liquid-crystalline siloxane polymers bearing terthiophene moieties as mesogenic pendant groups have been synthesized. An alkenylterthiophene derivative was treated with poly(hydrogenmethylsiloxane) and poly(dimethylsiloxane-co-hydrogenmethylsiloxane)s in Me(2)SiO/MeHSiO ratios of 1:1 and 7:3, respectively, in the presence of the Karstedt catalyst, to produce pale yellow polymers. The degrees of introduction of the mesogenic ...

The structural stability and phase transition of osmium and ruthenium carbides (OsC and RuC) were investigated by first principles. Nine structures were considered for each carbide. Zinc blende structure has the lowest energy among the considered structures at ambient conditions for both carbides. For OsC at elevated pressures, the most ...