Energetic Tuning in Spirocyclic Conjugated Polymers.

Precise control of the energy levels in a conjugated polymer is the key to allowing their exploitation in optoelectronic devices. The introduction of spirocycles into conjugated polymers has traditionally been used to enhance their solid state microstructure. Here we present a highly novel method of energetic tuning through the use of electronically active spirocyclic systems.

Cyclisation reactions of N-cinnamoyl-9-aminoanthracenes.

N-Cinnamoyl-9-aminoanthracenes cyclise with PPA or triflic acid to form novel 2-azahexacyclo[10.6.6.

Biomechanical comparison of reverse total shoulder arthroplasty systems in soft tissue-constrained shoulders.

Background: Numerous studies have examined the biomechanics of isolated variables in reverse total shoulder arthroplasty. This study directly compared the composite performance of two reverse total shoulder arthroplasty systems; each system was designed around either a medialized or a lateralized glenohumeral center of rotation.

Methods: Seven pairs of shoulders were tested on a biomechanical simulator.

The triflic acid-mediated cyclization reactions of N-cinnamoyl-1-naphthylamines.

N-cinnamoyl-1-naphthylamines undergo a cyclization reaction with triflic acid to form 4-phenyl-3,4-dihydro-1H-naphth[1,8-bc]azepin-2-ones and 4-phenyl-3,4-dihydro-1H-benzo[h]quinolin-2-ones. However, the N-benzyl analogues also undergo a unique cascade reaction to form novel heptacyclic structures via a 1,2-addition followed by a 4-addition to the naphthalene. With an electron-rich N-benzyl substituent, the heptacycle is the sole product.

The acid-mediated ring opening reactions of α-aryl-lactams.

4-Aryl-azetidin-2-ones (β-lactams) undergo ring opening with triflic acid to give cinnamamides which, in benzene, react further to give 3-aryl-3-phenyl-propionamides. Prolonged reaction times in benzene give 3,3-diphenyl-propionamide via an aryl/phenyl exchange. Lactams of ring size 7 and higher also ring open, but only 7- and 8-membered rings give pure diphenylalkylamides.

Structures in solutions from joint experimental-computational analysis: applications to cyclic molecules and studies of noncovalent interactions.

The potential of an approach combining nuclear magnetic resonance (NMR) spectroscopy, molecular dynamics (MD) simulations, and quantum mechanical (QM) calculations for full structural characterizations in solution is assessed using cyclic organic compounds, namely, benzazocinone derivatives 1-3 with fused five- and eight-membered aliphatic rings, camphoric anhydride 4, and bullvalene 5. Various MD simulations were considered, using force field and semiempirical QM treatments, implicit and explicit solvation, and high-temperature MD calculations for selecting plausible molecular geometries for subsequent QM geometry optimizations using mainly B3LYP, M062X, and MP2 methods. The QM-predicted values of NMR parameters were compared to their experimental values for verification of the final structures derived from the MD/QM analysis.

Triflic acid-mediated phenylation of N-acylaminoalkyl diethylacetals and N-acyl-2-phenyl cyclic amides.

The reaction of N-acylaminoalkyl diethylacetals with triflic acid in benzene gave N-acylamino-diphenylalkyls. The proposed intermediates are the N-acyl-2-phenyl cyclic amides, which themselves are similarly converted to N-acylamino-diphenylalkyls.

An engineered cardiac reporter cell line identifies human embryonic stem cell-derived myocardial precursors.

Unlike some organs, the heart is unable to repair itself after injury. Human embryonic stem cells (hESCs) grow and divide indefinitely while maintaining the potential to develop into many tissues of the body. As such, they provide an unprecedented opportunity to treat human diseases characterized by tissue loss.

A novel synthesis of (di)-benzazocinones via an endocyclic N-acyliminium ion cyclisation.

The triflic acid-mediated endocyclic N-acyliminium ion cyclisation provides a facile synthesis of (di)-benzazocinones. On reduction of the 10-phenyl derivative, an unusually non-polar tertiary alkylamine was obtained.

High-throughput tracking of pluripotent human embryonic stem cells with dual fluorescence resonance energy transfer molecular beacons.

Pluripotent human embryonic stem cells (hESCs) provide an unprecedented opportunity for the study of human tissue development, and the development of cell-based therapies for human disease. To realize these potential advances, however, methods for monitoring expression of intracellular proteins in live hESCs without altering cellular properties are needed. Molecular beacons are single-stranded oligonucleotides that have been employed to assay gene expression.

CC3/TIP30 affects DNA damage repair.

Background: The pro-apoptotic protein CC3/TIP30 has an unusual cellular function as an inhibitor of nucleocytoplasmic transport. This function is likely to be activated under conditions of stress. A number of studies support the notion that CC3 acts as a tumor and metastasis suppressor in various types of cancer.

Order and chaos in the rotation and revolution of a line segment and a point mass.

We study the classical dynamics of two bodies, a massive line segment or slash (/) and a massive point or dot (.), interacting gravitationally. For this slash-dot (/.

A facile synthesis of dibenzopyrroloazepinones as tetracyclic allocolchicinoids--an unusual 1,2-phenyl shift.

A facile synthesis of dibenzopyrroloazepinones via an electrophilic cyclisation of a biphenyl-acyliminium ion is described; an unusual 1,2-phenyl shift occurs when the C-1' carbon is the more nucleophilic than the C-2' carbon.

Timosaponin AIII is preferentially cytotoxic to tumor cells through inhibition of mTOR and induction of ER stress.

The aqueous extract of Anemarrhena asphodeloides (BN108) induces apoptosis in various cancer cell lines but is significantly less cytotoxic in non-transformed cells. Chemical fractionation of BN108 showed that its cytotoxicity is associated with timosaponins, steroidal saponins of coprostane type. Timosaponin BII (TBII) is a major saponin in BN108, but it shows little cytotoxicity.

An investigation into the electrophilic cyclisation of N-acyl-pyrrolidinium ions: a facile synthesis of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones.

The triflic acid-mediated cyclisation of N-arylmethyl- and N-arylethyl-acylpyrrolidinium ions gave moderate to good yields of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones respectively. Electron-donating R substituents enhanced the rate of reaction and gave higher yields than electron-withdrawing substituents. Substituents on the methyl or ethyl chain in general enhanced the reaction, unless sterically encumbered.

Subpopulations of human embryonic stem cells with distinct tissue-specific fates can be selected from pluripotent cultures.

Directed differentiation of human embryonic stem cells (hESCs) has generated much interest in the field of regenerative medicine. While subpopulations of hESCs within pluripotent cultures have been identified based on expression of specific surface antigens, their significance and fates are not well understood. To determine whether such subpopulations indicate specific tissue fates or represent stochastic antigen distributions within proliferating cultures, we isolated CD133(+) or CD135(+) hESCs from proliferating cultures constitutively expressing enhanced green fluorescent protein (GFP), and co-cultured these with unselected GFP(-) hESCs.

A facile synthesis of pyrrolo-(di)-benzazocinones via an intramolecular N-acyliminium ion cyclisation.

A facile, moderate to high yielding synthesis of hexahydro-(di)-benzazocinones is described via an intramolecular N-acyliminium ion cyclisation. The iminium ion intermediates are formed from the readily available 4,4-diethoxybutyl amides with an excess of triflic acid. For electron-withdrawing substituents, better yields were obtained from the pre-formed 2-hydroxypyrrolidine amides.

The identification of potent, selective and CNS penetrant furan-based inhibitors of B-Raf kinase.

Modification of the potent imidazole-based B-Raf inhibitor SB-590885 resulted in the identification of a series of furan-based derivatives with enhanced CNS penetration. One such compound, SB-699393 (17), was examined in vivo to challenge the hypothesis that selective B-Raf inhibitors may be of value in the treatment of stroke.

Stem cell antigen-1 localizes to lipid microdomains and associates with insulin degrading enzyme in skeletal myoblasts.

Stem cell antigen-1 (Sca-1, Ly6A/E) is a glycosylphosphotidylinositol-anchored protein that identifies many tissue progenitor cells. We originally identified Sca-1 as a marker of myogenic precursor cells and subsequently demonstrated that Sca-1 regulates proliferation of activated myoblasts, suggesting an important role for Sca-1 in skeletal muscle homeostasis. Beyond its functional role in regulating proliferation, however, little is known about the mechanism(s) that drive Sca-1-mediated events.

MicroRNA regulation of cell lineages in mouse and human embryonic stem cells.

Cell fate decisions of pluripotent embryonic stem (ES) cells are dictated by activation and repression of lineage-specific genes. Numerous signaling and transcriptional networks progressively narrow and specify the potential of ES cells. Whether specific microRNAs help refine and limit gene expression and, thereby, could be used to manipulate ES cell differentiation has largely been unexplored.

Electrical stimulation induced lumbar medial branch referral patterns.

Study Design: Fluoroscopically guided, minimum threshold electrical stimulation of the right first, second, third, and fourth lumbar medial branches and the fifth lumbar dorsal ramus in each of eight healthy test subjects was performed. The stimulation thresholds and referral patterns were recorded. A composite drawing of the referral patterns was created.

Practical synthesis of chiral vinylphosphine oxides by direct nucleophilic substitution. Stereodivergent synthesis of aminophosphine ligands.

[reaction: see text] A practical synthesis of optically pure alkylphenylvinylphosphine oxides is described, utilizing a nucleophilic displacement at phosphorus to install the vinyl moiety. The products were used to prepare classes of P-stereogenic aminophosphine (PN) and aminohydroxyphosphine (PNO) ligands. Stereocontrol can be exerted at various stages of the synthesis, to provide specific combinations of chirality in the final product.

The identification of potent and selective imidazole-based inhibitors of B-Raf kinase.

A novel triarylimidazole derivative, SB-590885 (33), bearing a 2,3-dihydro-1H-inden-1-one oxime substituent has been identified as a potent and extremely selective inhibitor of B-Raf kinase.

Tunable gold catalysts for selective hydrocarbon oxidation under mild conditions.

Oxidation is an important method for the synthesis of chemical intermediates in the manufacture of high-tonnage commodities, high-value fine chemicals, agrochemicals and pharmaceuticals: but oxidations are often inefficient. The introduction of catalytic systems using oxygen from air is preferred for 'green' processing. Gold catalysis is now showing potential in selective redox processes, particularly for alcohol oxidation and the direct synthesis of hydrogen peroxide.

Effect of structure of the redox molecular sieve TS-1 on the oxidation of phenol, crotyl alcohol and norbornylene.

A range of crystalline TS-1 samples with different morphologies as well as the corresponding TS-1 precursor structures have been synthesised using hydrothermal crystallisation. The materials have been characterised using powder X-ray diffraction, IR and Raman spectroscopy and electron microscopy. The materials were used as catalysts for the oxidation of crotyl alcohol, phenol and norbornylene and, in particular, the reactivity of the precursor structures was contrasted with crystalline TS-1.