Molecular analysis and genotype-phenotype correlation of Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) features hypoplastic anemia and congenital malformations, largely caused by mutations in various ribosomal proteins. The aim of this study was to characterize the spectrum of genetic lesions causing DBA and identify genotypes that correlate with phenotypes of clinical significance. Seventy-four patients with DBA from across Canada were included. Nucleotide-level mutations or large deletions were identified in 10 ribosomal genes in 45 cases. The RPS19 mutation group was associated with higher requirement for chronic treatment for anemia than other DBA groups. Patients with RPS19 mutations, however, were more likely to maintain long-term corticosteroid response without requirement for further chronic transfusions. Conversely, patients with RPL11 mutations were less likely to need chronic treatment. Birth defects, including cardiac, skeletal, hand, cleft lip or palate and genitourinary malformations, also varied among the various genetic groups. Patients with RPS19 mutations had the fewest number of defects, while patients with RPL5 had the greatest number of birth defects. This is the first study to show differences between DBA genetic groups with regards to treatment. Previously unreported differences in the rate and types of birth defects were also identified. These data allow better patient counseling, a more personalized monitoring plan, and may also suggest differential functions of DBA genes on ribosome and extra-ribosomal functions.

System for time-resolved laser absorption spectroscopy and its application to high-power impulse magnetron sputtering.

This paper deals with the development and construction of an apparatus for time-resolved tunable diode laser absorption spectroscopy (LAS) for the diagnostics of pulsed plasma. A detailed description of the extension of a progressive method of laser absorption spectroscopy in continuous regime to a direct triggering method of the time-resolved laser absorption spectroscopy (TR-LAS) is presented. The main advantage of the developed method is its capability to measure the time evolution of the whole absorption profile with a preset time resolution, which can be less than 1 µs. Therefore, the presented method of repetitive sampling applied on LAS in plasma processes is capable of simultaneous measurement of the density and kinetic temperature of selected particles. Its appropriate applications are to periodical processes in technological plasma, namely pulsed plasma discharges. The developed method of TR-LAS was applied to measurements of the temporal evolution of density and kinetic temperature of argon metastable species during high-power impulse magnetron sputtering of titanium and titanium dioxide thin films.

A modified Katsumata probe--Ion sensitive probe for measurement in non-magnetized plasmas.

A modified Katsumata probe has been developed for measurement of ion velocity distribution function (IVDF) in technological non-magnetized plasmas. A simple construction of the modified Katsumata probe consists of adding a pair of permanent Sm-Co magnets in front of Katsumata probe. A comparative study regarding IVDF measurement in a high power impulse magnetron sputtering system operating in pure argon atmosphere by means of developed modified Katsumata probe and commercially available gridded retarding field analyzer (RFA) has been carried out. A time-resolved measurement of IVDF for two different pressures whilst other plasma conditions have been kept unchanged has revealed that the main advantage of the modified Katsumata probe compared to the RFA consists in significantly smaller angular aperture of entrance orifice of modified Katsumata probe being approximately 15° in comparison with a commercial RFA having angular aperture more than 160°. It leads in much better velocity resolution in measured IVDF since the transversal part of velocity vector is much more suppressed compared to RFA. Furthermore, the modified Katsumata probe less suffers from collisions of ions in the space charge sheath in front or inside of the probe compared to the RFA.

Surface plasmon polaritons at linearly graded semiconductor interfaces.

New results are reported on investigation of dispersion curves for surface plasmon polaritons (SPPs) at an inhomogenously doped semiconductor/dielectric interface whereby the dielectric is represented by the same undoped semiconductor. The doped semiconductor is described by its frequency-dependent permittivity that varies with the depth. It is shown that a transition layer (TL) with a linear change in carrier concentration supports one branch dispersion curve regardless of the TL thickness. The obtained dispersion curves reach a maximum at a finite frequency depending on the TL thickness, and subsequently asymptotically approach the zero frequency in the shortwave limit. Therefore two surface plasmon modes are supported at a given frequency: a long-wave mode with a positive group velocity and a short-wave mode with a negative group velocity. A condition of a zero group velocity can be satisfied by tuning the TL layer. It is shown that the conventional dispersion relation for SPPs at a TL with a zero thickness is an asymptotic solution, and the convergence of real dispersion curves is point-wise instead of an expected uniform convergence.

Time-resolved tunable diode laser absorption spectroscopy of pulsed plasma.

A method for time-resolved tunable diode laser absorption spectroscopy (LAS) has been developed. In this Letter, we describe in detail a developed electronic module that controls the time resolution of the LAS system. The transistor-transistor logic signal triggering the plasma pulse is used for generation of two signals: the first one triggers fine tuning of the laser wavelength and the second one controls time-defined signal sampling from the absorption detector. The described method and electronic system enable investigation of the temporal evolution of the density and temperature of selected particles in technological plasma systems. The high-power impulse magnetron sputtering system with a period of 10 ms and a duty cycle of 1% has been used to verify this method. The temporal evolution of argon metastable density was measured in the active part of the pulse and in the afterglow. The resulting density of Ar* displays a double-peak structure with a first peak in the plasma "ON" phase and a second peak in the afterglow approximately 1 ms after the end of the pulse.

Combined posterior sagittal and three-flap anoplasty in the repair of anorectal anomalies.

PURPOSE: The aim of this study was to describe a new technique for the repair of high and intermediate imperforate anus. METHODS: From 1989 to 1999, 22 children with high and intermediate imperforate anus (17 boys, 5 girls) were operated on with a combination of a posterior sagittal and 3-flap perineal anoplasty. Long-term clinical follow up (to a maximum of 10 years) was done in all patients as well as a recent phone interview with a questionnaire regarding bowel function and degree of satisfaction with the result of the surgical correction. A continence ratio (CR, patient score/maximum possible score) was obtained by a blinded interviewer. RESULTS: A continence survey was obtained in 19 patients. The average CR was 0.68. The CR for high anomalies was 0.62 and for intermediate anomalies was 0.78 (0.84 for girls and 0.64 for boys). Patients with sacral anomalies had a CR of 0.58. Two patients with Trisomy 21 had associated Hirschsprung's disease and were excluded from analysis. CONCLUSIONS: Advantages of this combined surgical approach are excellent anatomic exposure, the ability to limit rectal mobilization to a minimum, reduction of the incidence of mucosal prolapse, the new skin-lined anal canal may assist attainment of continence by providing a "sensory warning zone," and, finally, the cosmetic appearance is satisfactory.

Interferometric optical fourier-transform processor for calculation of selected spatial frequencies.

A novel interferometric optical Fourier-transform processor is presented that calculates the complex-valued Fourier transform of an image at preselected points on the spatial-frequency plane. The Fourier spectrum of an arbitrary input image is interfered with that of a reference image in a common-path interferometer. Both the real and the imaginary parts of the complex-valued spectrum are determined. The source and the reference images are easily matched to guarantee good fringe visibility. At least six interferograms are postprocessed to extract the real and the imaginary parts of the Fourier spectrum at preselected points. The proposed hybrid optical-digital technique is computationally appropriate when the number of desired spatial frequencies is small compared with the number of pixels in the image. When the number of desired points is comparable with the number of image pixels, a conventional or pruned two-dimensional fast Fourier transform is more appropriate. The number of digital operations required by the hybrid optical-digital Fourier processor is proportional to the number of desired spatial frequencies rather than the number of pixels in the image. The points may be regularly distributed over the spatial-frequency plane or concentrated in one or several irregularly shaped regions of interest. The interferometric optical Fourier processor is demonstrated in a moving-object trajectory estimation system. The system successfully estimates the trajectory of multiple objects moving over both stationary and white-noise backgrounds. A comparison of performance was made with all-digital computation. With everything else equal, our hybrid optical-digital calculation was more than 3 orders of magnitude faster.

Transforming growth factor-beta regulates Kit ligand expression in rat ovarian surface epithelial cells.

In preparation for ovulation, paracrine communication between the preovulatory follicle and overlying theca/stromal cells and ovarian surface epithelium (OSE) must take place to facilitate the degradative and apoptotic events associated with ovulation. Kit tyrosine kinase receptors and their ligand, kit ligand (KL) are expressed within ovarian follicles, and ligand-induced receptor activation appears to account for some of the cell - cell interactions important for oocyte development. We investigated the expression of Kit receptors and KL in OSE cells and the possibility that modulation of their expression could affect OSE cell activity. KL mRNA and protein were detected in the OSE cell layer of rat ovaries, and primary cultures of rat OSE as well as the immortalized rat OSE cell line, ROSE 199, expressed KL, but not Kit receptors. Both primary and immortalized OSE cells preferentially expressed KL-1, rather than KL-2, transcripts, suggesting that these cells produce predominantly the soluble form of KL. Activation of the cAMP signalling pathway using dibutyryl cAMP decreased proliferation of ROSE 199 cells and elicited a threefold increase in KL expression. TGF-beta similarly inhibited ROSE 199 cell proliferation, but strongly inhibited dibutyryl cAMP-induced KL expression, indicating that changes in KL expression were not directly associated with OSE cell proliferation. The expression of mostly soluble KL in the surface epithelium suggests that this cytokine may be acting in a paracrine fashion, perhaps interacting with nearby Kit receptor-bearing theca cells.

Optical Fourier processor and point-diffraction interferometer for moving-object trajectory estimation.

A hybrid optical-digital signal processing system that estimates the trajectory of moving targets in a two-dimensional field at video frame rates was developed and constructed. The hybrid system is particularly well suited to the trajectory estimation of small, barely discernable, moving objects of unknown position and velocity in high-resolution image sequences. The system uses an optical Fourier processor and a point-diffraction interferometer to calculate the frequency-domain representation of moving objects from which their trajectory is estimated by use of conventional electronic processing techniques. In a series of experiments, target velocities were estimated to within 4% of their actual value and direction was estimated to within 3 deg.