Canadian Light Source

Phosphorylating glyceraldehyde-3-P dehydrogenase (GAPC-1) is a highly conserved cytosolic enzyme that catalyzes the conversion of glyceraldehyde-3-P to 1,3-bis-phosphoglycerate; besides its participation in glycolysis, it is thought to be involved in additional cellular functions. To reach an integrative view on the many roles played by this enzyme, we characterized a homozygous gapc-1 null mutant and an as-GAPC1 line of Arabidopsis (Arabidopsis thaliana). Both mutant plant lines show a delay in growth, morphological alterations in siliques, and low seed number. Embryo development was altered, showing abortions and empty embryonic sacs in basal and apical siliques, respectively. The gapc-1 line shows a decrease in ATP levels and reduced respiratory rate. Furthermore, both lines exhibit a decrease in the expression and activity of aconitase and succinate dehydrogenase and reduced levels of pyruvate and several Krebs cycle intermediates, as well as increased reactive oxygen species levels. Transcriptome analysis of the gapc-1 mutants unveils a differential accumulation of transcripts encoding for enzymes involved in carbon partitioning. According to these studies, some enzymes involved in carbon flux decreased (phosphoenolpyruvate carboxylase, NAD-malic enzyme, glucose-6-P dehydrogenase) or increased (NAD-malate dehydrogenase) their activities compared to the wild-type line. Taken together, our data indicate that a deficiency in the cytosolic GAPC activity results in modifications of carbon flux and mitochondrial dysfunction, leading to an alteration of plant and embryo development with decreased number of seeds, indicating that GAPC-1 is essential for normal fertility in Arabidopsis plants.

We produced coherent synchrotron radiation at the Canadian Light Source between about 5 and 30 cm −1 in bursting and continuous emission modes and used it to acquire photoacoustic spectra of solids. A band was observed in the spectrum of α-lactose monohydrate at 18 cm −1 and attributed to a rotational mode, in agreement with published data obtained using other numerical and experimental techniques.

Standard commercial infrared microscopes operating in reflection mode use a mirror to direct the reflected light from the sample to the detector. This mirror blocks about half of the incident light, however, and thus degrades the spatial resolution by reducing the numerical aperture of the objective. Here, we replace the mirror with a 50% beamsplitter to allow full illumination of the objective and retain a way to direct the reflected light to the detector. The improved spatial resolution is demonstrated using two different microscopes capable of diffraction-limited resolution: the first microscope is coupled to a synchrotron source and utilizes a single point detector, whereas the second microscope has a standard blackbody source and uses a focal plane array (FPA) detector.

Glioblastoma multiforme (GBM) is one of the most malignant human tumors, with a uniformly poor outcome. One obstacle in curing malignant brain tumors is the limitation of conventional light microscopy in detecting microscopic residual tumor in biopsy samples from the perimeter of the surgically resected tumor. We further refined the identification of GBM tumor tissue at the sub-cellular level, utilising the technique of Synchrotron, sourced mid-infrared (mid-IR) spectromicroscopy. Paired, thin (5 microm) cryosections of snap-frozen human GBM tumor samples removed at elective surgery were mounted on glass slides (hematoxylin and eosin-stained tissue section) and calcium fluoride (CaF2) windows (unstained tissue section for transmission spectromicroscopy), respectively. Concordance of tumor bearing areas identified in the stained section with the unstained IR tissue section was confirmed by the pathologist of the study. Compared with molecular signatures obtained from normal control b...

Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate the solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (log P), Henry's law constants (HLC), dipole moments, static relative permittivities (ε(r)), solvatochromic E(T)(30) parameters, Kamlet-Taft parameters (β, α, and π), Catalan's solvatochromic parameters (SPP, SB, and SA), Hildebrand solubility parameters (δ(i)), and Hansen solubility parameters (δ(p), δ(d), δ(h)) and the associated Hansen distance (R(ij)) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach pres...

Bunches of high charge (up to 10 nC) are compressed in length in the CTF II magnetic chicane to less than 0.2 mm rms. The short bunches radiate coherently in the chicane magnetic field, and the horizontal and longitudinal phase space density distributions are affected. This paper reports the results of beam emittance and momentum measurements. Horizontal and vertical emittances and momentum spectra were measured for different bunch compression factors and bunch charges. In particular, for 10 nC bunches, the mean beam momentum decreased by about 5% while the FWHM momentum spread increased from 5% to 19%. The experimental results are compared with simulations made with the code TraFiC 4 .

We report the first high-resolution measurement of superradiance, using coherent synchrotron radiation in the terahertz region from the Canadian Light Source synchrotron and a Michelson interferometer with a nominal frequency resolution of 0:000 96 cm À1 . Superradiance arises when a high degree of phase coherence exists between the radiation fields of the individual electron bunches, and manifests itself as a series of narrow spectral peaks at harmonics of the bunch frequency. We observe an enhancement factor of 16 at the spectral peaks, limited by the interferometer resolution. The spectral distribution and relative amplitudes of the superradiant peaks are modified by altering the pattern of bunches along the bunch train.

Limitations of conventional light microscopy in pathological diagnosis of brain tumors include subjective bias in interpretation and discordance of nomenclature. A study using mid-infrared (IR) spectromicroscopy was undertaken to determine whether meningiomas, a group of brain tumors prone to recurrence, could be identified by the unique spectral 'fingerprints' of their chemical composition. Paired, thin (5-microm) cryosections of snap-frozen human meningioma tumor samples removed at elective surgery were mounted on glass (hematoxylin and eosin-stained tissue section) and infrared (unstained tissue section) reflectance slides, respectively. Concordance of the tumor-bearing areas identified in the stained section by a pathologist with the unstained IR tissue section was ensured using a novel digital grid and tumor-mapping system developed in our laboratory. Compared with the normal control, tumor samples from four meningioma patients revealed a marked decrease in bands associ...

Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (logP), Henry's law constants (HLC), dipole moments, static relative permittivities (εr), solvatochromic ET(30) parameters, Kamlet-Taft parameters (β, α and π), Catalan's solvatochromic parameters (SPP, SB and SA), Hildebrand solubility parameters (δi), and Hansen solubility parameters (δp, δd, δh) and the associated Hansen distance ( Rij) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach presented describes the ...

Synchrotron radiation from the new Canadian Light Source facility has been used to obtain a high resolution (0.0012 cm À1 ) absorption spectrum of acrolein vapor in the 550-660 cm À1 region. Almost 2000 transitions have been included in a detailed analysis of the m 12 ($564 cm À1 ) and m 17 ($593 cm À1 ) fundamental bands which yielded precise values for the band origins, rotational and centrifugal distortion parameters. The analysis included the a-and b-type Coriolis interactions connecting m 12 and m 17 , as well as an a-type Coriolis interaction between m 17 and a ''dark'' perturbing state, identified as 4m 18 . We believe that this is the first high resolution infrared study of acrolein.

The Canadian Light Source, Inc. is designing and building facilities for Infrared Spectroscopy. Two types of beamlines covering the Mid-and Far-Infrared are planned [1]. One will supply light to commercial Fourier Transform Infrared (FTIR) spectrometers and microscopes for biological and industrial applications. The second will use a vacuum FTIR spectrometer and user-specific experimental attachments. The Mid-Infrared beamlines cover 2 to 25 micron wavelengths while the Far-Infrared beamline provides wavelengths beyond 25 micron. Flux and brilliance (brightness) curves for the Infrared beam lines are reported. The calculations are made to provide working values for the design, construction, and evaluation of the beamlines. Tailoring the bending magnet port size to the wavelength region of interest improves the expected performance for the Mid-and Far-Infrared. Obtaining aperture dimensions aids design of the dipole vacuum chamber and in-vacuum mirror mounts. A comparison to several Infrared beamlines in operation and to a standard thermal source is made to gauge performance. Dipole bending magnet radiation is the basis for comparison. Values obtained using standard bend radiation formulas are compared with values obtained using SRW, Synchrotron Radiation Workshop [2]. Port geometry for attaining this performance and requirements for the first optical element design is discussed.

An infrared beamline has been constructed at the 800 MeV electron storage ring, Aladdin. The beamline is located downstream of a short straight section, where it collects edge radiation produced by electrons exiting and entering the bending magnets at the ends of the straight section. Measurements at wavelengths of 1-5 µm suggest that the edge radiation is brighter than standard synchrotron radiation. When used for Fourier transform infrared (FTIR) microspectroscopy, the signal-to-noise ratio is 20 times that measured with a glower source. Several applications of the beamline are described.