Macroporous hydrogel micropillars for quantifying Met kinase activity in cancer cell lysates

Overactive and overexpressed kinases have been implicated in the cause and progression of many cancers. Kinase inhibitors offer a targeted approach for treating cancers associated with increased or deregulated kinase activity. Often, however, cancer cells exhibit initial resistance to these inhibitors or evolve to develop resistance during treatment. Additionally, cancers of any one tissue type are typically heterogeneous in their oncogenesis mechanisms, and thus diagnosis of a particular type of cancer does not necessarily provide insight into what kinase therapies may be effective. For example, while some lung cancer cells that overexpress the epidermal growth factor receptor (EFGR) respond to treatment with EGFR kinase inhibitors, overexpression or hyperactivity of Met kinase correlates with resistance to EGFR kinase inhibitors. Here we describe a microfluidic-based assay for quantifying Met kinase activity in cancer cell lysates with the eventual goals of predicting cancer cell responsiveness to kinase inhibitors and monitoring development of resistance to these inhibitors. In this assay, we immobilized a phosphorylation substrate for Met kinase into macroporous hydrogel micropillars. We then exposed the micropillars to a cancer cell lysate and detected substrate phosphorylation using a fluorescently conjugated antibody. This assay is able to quantify Met kinase activity in whole cell lysate from as few as 150 cancer cells. It can also detect cells expressing overactive Met kinase in a background of up to 75% non-cancerous cells. Additionally, the assay can quantify kinase inhibition by the Met-specific kinase inhibitors SU11274 and PHA665752, suggesting predictive capability for cellular response to kinase inhibitors.     

Structural analysis of the β-SiC(100)-(2 × 1) surface reconstruction by automated tensor LEED

The atomic structure of the β-SiC(100)-(2 × 1) surface was analyzed using dynamical calculations of low energy electron diffraction (LEED) intensities measured with a video camera. Surface composition was monitored using Auger electron spectroscopy (AES). The LEED calculations utilized our recently developed automated tensor LEED method. The results indicate that the surface is terminated by a monolayer of silicon with the topmost silicon atoms forming asymmetric, buckled dimers.     

Pionic 3d → 2p X-ray measurements in 50,52,54Cr, 45Sc, 51V, 55Mn and Fe

We report the measurement of the strong interaction shifts and widths of the pionic 3d → 2p transitions in separated isotopes of ^50,52,54Cr and natural Sc, V, Mn, and Fe. Using these new data in combination with earlier low-Z pionic data (6 ? Z ? 20) we have studied the phenomenological pion-nuclear potential. Employing nuclear structure information from measured charge densities and Hartree-Fock calculations, we have fitted the pion-nuclear potential parameters to the pionic-atom data. We have explored the sensitivity of these data to the value of the Lorentz-Lorenz parameter ξ. The addition of an isovector dependence to the s- and p-wave two-nucleon terms is shown to be unnecessary at the present level of experimental accuracy. We have used the deduced optical potentials to determine the neutron radii of the nuclei 20 ? Z ? 26 and find reasonable agreement with Hartree-Fock predictions and with the results of other hadronic probes for 20 ? Z ? 23 but poor agreement for 24 ? Z ? 26.     

Recognition of CG inversions in DNA triple helices by methylated 3H-pyrrolo[2,3-d]pyrimidin-2(7H)-one nucleoside analogues

Substituted 3H-pyrrolo[2,3-d]pyrimidin-2(7H)-one nucleoside analogues have been synthesised from 5-alkynyl-uridine derivatives, incorporated into triplex forming oligonucleotides (TFOs) and found to selectively bind CG inversions with enhanced affinity compared to T.     

Dilithiation of 1-benzenesulfonylindoles

Benzenesulfonylindole is converted to a dilithio derivative by 2.2 equivalents of lithiating reagent. The dilithio derivative gives rise to sultones on reaction with carbonyl compounds. This reaction proceeds by an intramolecular displacement of the indole group from the bis-adduct. Fair to poor yields of the 2-indolycarbinols can also be isolated. Benzoyl chloride forms a thiazine dioxide ring by addition at both the 2-indolyl and 2′-phenylsulfonyl positions. 3-Methyl-1-benzenesulfonylindole is also easily dilithiated.     

Terahertz generation with tandem seeded optical parametric generators

A simple difference frequency generation (DFG) scheme based on two seeded optical parametric generators is presented as a tunable terahertz (THz) source. Using the nonlinear optical crystal 4-dimethylamino-N-methyl-4-stilbazolium-tosylate (DAST) as the DFG crystal, our system has demonstrated continuous and seamless tunable operation from 1.6 to 4.5 THz. The output bandwidth of the THz source is 2.4 GHz. The utility of the source over this spectral range is demonstrated by measuring a high-resolution transmission spectrum of water vapor in air.     

Tunable Crystallinity and Charge Transfer in Two‐Dimensional G‐Quadruplex Organic Frameworks

DNA G‐quadruplex structures were recently discovered to provide reliable scaffolding for two‐dimensional organic frameworks due to the strong hydrogen‐bonding ability of guanine. Herein, 2,7‐diaryl pyrene building blocks with high HOMO energies and large optical gaps are incorporated into G‐quadruplex organic frameworks. The adjustable substitution on the aryl groups provides an opportunity to elucidate the framework formation mechanism; molecular non‐planarity is found to be beneficial for restricting interlayer slippage, and the framework crystallinity is highest when intermolecular interaction and non‐planarity strike a fine balance. When guanine‐functionalized pyrenes are co‐crystallized with naphthalene diimide, charge‐transfer (CT) complexes are obtained. The photophysical properties of the pyrene‐only and CT frameworks are characterized by UV/Vis and steady‐state and time‐resolved photoluminescence spectroscopies, and by EPR spectroscopy for the CT complex frameworks.     

Continuous tuning of a continuous-wave periodically poled lithium niobate optical parametric oscillator by use of a fan-out grating design

We report on a new periodically poled lithium niobate grating design with a continuous grating-period change (fan-out). We observed 350cm(-1) (80 nm at 1.5microm) of complete spectral coverage at a constant temperature in a cw optical parametric oscillator. Complete spectral coverage is demonstrated by measurement of an absorption band of CO(2) .     

Thermal reactions of 8-methylbicyclo[4.2.0]oct-2-enes: competitive diradical-mediated [1,3] sigmatropic, stereomutation, and fragmentation processes

[reaction: see text] At 275 degrees C, 8-exo-methylbicyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-methylbicyclo[2.2.2]oct-2-enes, of which the orbital symmetry-allowed si product is only marginally favored over the forbidden sr product; that is, si/sr is 2.4. Accompanying the [1,3] shift are significant amounts of epimerization and fragmentation. The 8-endo epimer 1b, which yields no [1,3] product, experiences primarily direct fragmentation and secondarily epimerization. A diradical intermediate can account for all such observations.