Function-based Intersubject Alignment of Human Cortical Anatomy

Making conclusions about the functional neuroanatomical organization of the human brain requires methods for relating the functional anatomy of an individual's brain to population variability. We have developed a method for aligning the functional neuroanatomy of individual brains based on the patterns of neural activity that are elicited by viewing a movie. Instead of basing alignment on functionally defined areas, whose location is defined as the center of mass or the local maximum response, the alignment is based on patterns of response as they are distributed spatially both within and across cortical areas. The method is implemented in the two-dimensional manifold of an inflated, spherical cortical surface. The method, although developed using movie data, generalizes successfully to data obtained with another cognitive activation paradigm—viewing static images of objects and faces—and improves group statistics in that experiment as measured by a standard general linear model (GLM) analysis

Matlab application for fitting progress curves to the Equilibrium Model

The general procedures for carrying out the necessary rate determinations required for accurate determination of the Equilibrium Model parameters, and fitting this data to the mathematical model to generate the parameters, are described in "Peterson, M.E., Daniel, R.M., Danson, M.J. & Eisenthal, R. (2007) The dependence of enzyme activity on temperature: determination and validation of parameters. Biochemical Journal, 402, 331-337". It should be borne in mind that the Equilibrium Model equation contains exponentials of exponentials – quite small deviations from ideal behaviour, or a failure to obtain true Vmax values, may lead to difficulty in obtaining reliable Equilibrium Model parameters

Stress Sensing in Polycaprolactone Films via an Embedded Photochromic Compound

A photochromic polymer exhibiting mechanochromic behavior is prepared by means of ring-opening polymerization (ROP) of epsilon-caprolactone by utilizing a difunctional indolinospiropyran as an initiator. The configuration of having the photochromic initiating species within the polymer backbone leads to a mechanochromic effect with deformation of polymer films leading to ring-opening of the spiro C-O bond to form the colored merocyanine. Active stress monitoring by dynamic mechanical analysis (DMA) in tension mode was used to probe the effects of UV irradiation on polymer films held under constant strain. Irradiation with UV light induces a negative change in the polymer stress of approximately 50 kPa. Finally, a model of the mechanochromic effect was performed using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. A sharp increase in the relative molecular energy and the absorption wavelength as well as a drastic decrease in the spiro-oxygen atom charge occurred at a molecular elongation of >39%

Three-dimensional range imaging apparatus and method

A three-dimensional range imager includes a light source for providing a modulated light signal, a multiplexer, an optical fiber connecting the light source to the multiplexer, a plurality of optical fibers connected at first ends to the multiplexer and at second ends to a first fiber array, and a transmitter optic disposed adjacent the first fiber array for projecting a pixel pattern of the array onto a target

Flexibility in the receptor-binding domain of the enzymatic colicin E9 is required for toxicity against Escherichia coli cells

The events that occur after the binding of the enzymatic E colicins to Escherichia coli BtuB receptors that lead to translocation of the cytotoxic domain into the periplasmic space and, ultimately, cell killing are poorly understood. It has been suggested that unfolding of the coiled-coil Mull receptor binding domain of the E colicins may be an essential step that leads to the loss of immunity protein from the colicin and immunity protein complex and then triggers the events of translocation. We introduced pairs of cysteine mutations into the receptor binding domain of colicin E9 (ColE9) that resulted in the formation of a disulfide bond located near the middle or the top of the R domain. After dithiothreitol reduction, the ColE9 protein with the mutations L359C and F412C (ColE9 L359C-F412C) and the ColE9 protein with the mutations Y324C and L447C (ColE9 Y324C-L447C) were slightly less active than equivalent concentrations of ColE9. On oxidation with diamide, no significant biological activity was seen with the ColE9 L359C-F412C and the ColE9 Y324C-L447C mutant proteins; however diamide had no effect on the activity of ColE9. The presence of a disulfide bond was confirmed in both of the oxidized, mutant proteins by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The loss of biological activity of the disulfide-containing mutant proteins was not due to an indirect effect on the properties of the translocation or DNase domains of the mutant colicins. The data are consistent with a requirement for the flexibility of the coiled-coil R domain after binding to BtuB

Low-density series expansions for directed percolation I: A new efficient algorithm with applications to the square lattice

A new algorithm for the derivation of low-density series for percolation on directed lattices is introduced and applied to the square lattice bond and site problems. Numerical evidence shows that the computational complexity grows exponentially, but with a growth factor \lambda < \protect{\sqrt[8]{2}}, which is much smaller than the growth factor \lambda = \protect{\sqrt[4]{2}} of the previous best algorithm. For bond (site) percolation on the directed square lattice the series has been extended to order 171 (158). Analysis of the series yields sharper estimates of the critical points and exponents.Comment: 20 pages, 8 figures (3 of them > 1Mb

Synthesis of Unsymmetrical Bis(phosphine) Oxides and Their Phosphines via Secondary Phosphine Oxide Precursors

The unsymmetrical bidentate phosphine ligands (Me)2PCH2CH2CH2P(Et)2 (14), (Me)2PCH2CH2CH2P(iPr)2 (15), (Me)2PCH2CH2CH2P(Cy)2 (16), and (Me)2PCH2CH2CH2P(Ph)2 (17) were synthesized using air–stable phosphine oxide intermediates. In the first step, sodium phosphinites formed by deprotonation of (Me)2P(O)H, (Et)2P(O)H, and (iPr)2P(O)H were alkylated by 1-bromo-3-chloropropane. The different substitution rates of the chloride and bromide groups allowed the isolation of the intermediates (Me)2P(O)CH2CH2CH2Cl (2), (Et)2P(O)CH2CH2CH2Cl (3), and (iPr)2P(O)CH2CH2CH2Cl (4). Subsequent reaction of (Me)2P(O)CH2CH2CH2Cl (2) with the sodium phosphinites generated from (Et)2P(O)H, (iPr)2P(O)H, (tBu)2P(O)H, (Cy)2P(O)H, or (Ph)2P(O)H gave unsymmetrical bidentate phosphine oxides; reduction of these oxides yielded the unsymmetrical phosphines. The unsymmetrical bidentate phosphines react with metal salts to form complexes. X-ray crystal structures of cis-Pt((Me)2P(CH2CH2CH2)P(iPr)2)Cl2 (20) and racemic [CuI((Me)2P(CH2CH2CH2)P(Ph)2)]Cl (21) were obtained. The kinetics and scope of the synthetic route were also explored. Experiments showed that the rate of substitution of the alkyl chloride group in (R)2P(O)CH2CH2CH2Cl-type oxides increases relative to unsubstituted alkyl chlorides due to the presence of the phosphonyl group on one end of the molecule. The scope of the reaction involving 1,2-dihaloalkanes was also investigated, and it was found that the reaction mixture of sodium dimethylphosphinite and 1,2-dihaloalkanes formed tetramethylbis(phosphine) monoxide (22), which decomposes on work-up to give complex reaction mixtures