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Background: Spinal muscular atrophy (SMA) is a children’s neuromuscular disorder. Although motor neuron loss is a major feature of the disease, we have identified fatty acid abnormalities in SMA patients and in preclinical animal models, suggesting metabolic perturbation is also an important component of SMA. Methods: Biochemical, histological, proteomic, and high resolution respirometry were used. Results: SMA patients are more susceptible to dyslipidemia than the average population as determined by a standard lipid profile in a cohort of 72 pediatric patients. As well, we observed a non-alcoholic liver disease phenotype in apreclinical mouse model. Denervation alone was not sufficient to induce liver steatosis, as a mouse model of ALS, did not develop fatty liver. Hyperglucagonemia in Smn2B/-mice could explain the hepatic steatosis by increasing plasma substrate availability via glycogen depletion and peripheral lipolysis. Proteomic analysis identified mitochondrion and lipid metabolism as major clusters. Alterations in mitochondrial function were revealed by high-resolution respirometry. Finally, low-fat diets led to increased survival in Smn2B/-mice. Conclusions: These results provide strong evidence for lipid metabolism defects in SMA. Further investigation will be required to establish the primary mechanism of these alterations and understand how they lead to additional co-morbidities in SMA patients.
To develop sustainable grazing systems, an understanding of the complex interactions between competing plant species and grazing herbivores is needed. An understanding of dietary preference is a prerequisite to predicting how much and from which plant species animals select. This work initially concentrated on dietary preferences of sheep grazing perennial ryegrass and white clover swards and was then extended to other animal species to test the generality of our findings.
The UN millennium goal of halving the percent of people in poverty in Sub-Saharan Africa by 2015, will not be achieved. Where animal scientists have contributed to this failure, they have assumed that small farms are inefficient and will be improved by adopting scaled-down versions of the large commercial systems in which their science has evolved. Kenya illustrates the problem, with its rural poverty and a project to increase the standard of living of smallholders through milk production. Despite the socio-economic difference from the large dairy farm, the cow of choice for these small zero-grazing units remains the Friesian (F), but her productivity is so low as to threaten the sustention of the system (Bebe, 2003). We need to understand why the breed is popular, what shapes the lactation curve and extends the calving interval (CI), and what are sustainable levels of milk and calf production.
Integrated management systems (IMS) for pigs offer the prospects of optimising meat production and minimising nitrogenous pollution through closed-loop control of pig growth by nutritional control (Whittemore, et al., 2001). Such an IMS requires a real-time sensor system, a nutritional model which is optimised in response to data collected in by the sensor system, and a control system which uses forward predictions of the model to predict the nutritional regime required to satisfy growth and pollution targets. An experiment was carried out to determine the accuracy to which a novel IMS system can direct pig weight gain and fatness towards preset targets through nutritional control.
The purpose of an integrated management system is to optimise both pig performance and environmental protection. A major impediment to this process has been the inability to measure and control the production process in real time, for specific and contemporary pig batches. Optimisation thus requires in-line measurement of pig growth performance, together with the means to change performance with adjustments to feed quantity and quality. This report deals with the use of visual image analysis (VIA) to provide the first of these; measurement of growth. VIA determines, continuously and in-line, the size and shape of the plan view of the pig as it stands at the feeder. Three seminal questions are here addressed. (i) can VIA be used to provide a reliable measure of pig weight, and (ii) how many days are required to elapse before a change in size can be reliably determined and how does the VIA system compare with daily weighing by a conventional weigh-scale, and (iii) can VIA sort pigs according to their shape?
During the Skylab I, II and III missions, ultraviolet spectra were obtained in 188 fields with a. 15 cm aperture objective-prism spectrograph. The instrument has been described by Henize, Wray, Parsons, Benedict, Bruhweiler, Rybski and O’Callaghan (1975; hereafter referred to as Paper I).
The spectra cover the wavelength region from 1300 to 5000 Å and have a resolution of 2 Å at 1400 Å and 12 Å at 2000 Å. Absorption and/or emission lines of C II λ 1335, Si IV λ 1394, 1403 and C IV λ 1549 are visible in more than one hundred stars. The lines of Si IV and C IV are found to be particularly sensitive to stellar temperature and luminosity. Since these lines are visible in spectra of moderate to low resolution it is clear that they should be of special interest in any UV classification system for faint stars. This paper investigates the correlation of the intensities of the C IV and Si IV lines with MK spectral type, and presents a preliminary classification scheme for 04 to B2 stars based on these lines.
The S-019 experiment on Skylab (cf. Henize et al. 1975; “Paper I”) recorded far UV spectra in about 160 4° x 5° fields, covering 10% of the sky, on 101 film with a 15 cm aperture objective-prism telescope. Several hundred early-type stars were observed in the vicinity of 1550 Å with a resolution between 3 and 4 Å, as well as thousands of stars at longer wavelengths and correspondingly lower resolution. An atlas of spectra for types 04 to B5 is illustrated in Paper I. That figure shows that the P Cygni profile is a characteristic of all supergiants earlier than B3 and main sequence stars earlier than 08.
The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4–∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.
Sputter-deposited Co/Cu multilayers at the 1st antiferromagnetic maximum (tCu= 9Å) exhibit large magnetoresistance and low relative hysteresis and are attractive for use in many position sensor applications. Unfortunately, their large magnetoresistance values can be hard to reproduce, perhaps a consequence of the difficulties in growing flat, pin-hole free layers. In this study we demonstrate that their magnetoresistive properties can be improved with the addition O2 to the Ar sputtering gas. A sequence of [Co(15Å)/Cu(9Å)]20 multilayers were made using magnetron sputtering in a 2mTorr Ar+O2 atmosphere, with the O2 concentration ranging from <1 ppm to 10,000 ppm. For films sputtered in our purest Ar, the magnetoresistance was typically less than 10%. Adding small amounts of O2 to the Ar improved the magnetoresistance, and at 1000 ppm O2 concentration it reached an optimal value of ∼45% and was found to be quite reproducible. The largest saturation fields were also achieved at 1000 ppm O2. Increasing the O2 concentration beyond 1000 ppm degraded the magnetoresistance and reduced the saturation fields. Magnetic measurements indicate that the improved magnetoresistance for films sputtered in Ar + O2 is primarily a consequence of more complete antiferromagnetic ordering at low fields. Auger depth profiling revealed no evidence for the O2 incorporation into the films, even for those fabricated in 10,000 ppm O2. Influence of the O2 on the microstructure of the multilayers is discussed.
Simulations of reflectance spectra and electric field distributions for vertical-cavity structures were used in the computer aided design of epitaxial mirrors and lasers. The binary GaAs/AlAs superlattice alloys and AlxGa1−xAs random alloys that compose these structures were grown by molecular beam epitaxy. Photoluminescence, photoreflectance, reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, and double crystal x-ray diffractometry were applied to characterize cavity and Bragg mirror layer thicknesses and alloy composition.
Beta SiC is an important semiconductor whose development has been slowed by synthesis difficulties. The physical and electronic properties which make β-SiC desirable for high speed and high power electronics are discussed, with special emphasis on field effect transistor (FET) applications. A history of synthesis efforts is presented to illuminate the obstacles encountered in the growth of semiconductor device quality P-SiC. A new approach to single crystal epitaxy of β-SiC, using TiC as a substrate, is described. The properties of TiC which make it a uniquely suitable substrate for β-SiC epitaxial growth are discussed, and procedures used to prepare TiC surfaces for β-SiC epitaxy are described. The growth process employed at our laboratory, chemical vapor deposition (CVD), is described, and experimental observations of the effects of the CVD growth environment on β-SiC epitaxial growth are presented. Based on these observations, we propose to synthesize β-SiC in a singlesource reaction, using molecules which decompose directly to SiC units. This contrasts with current approaches, which introduce Si and C separately, in molecules which must decompose and subsequently react to form SiC.
A β-SiC epitaxial growth process, using 1,2-disilylethane (DES), was developed. DSE was selected because it contains an equal number of C and Si atoms and its reported decomposition characteristics suggest that C and Si could be obtained from it at approximately equal rates. Repeatable nucleation and epitaxial growth conditions, giving complete substrate coverage and controlled growth, were established by atmospheric pressure CVD, in an inverted-vertical reactor. A substrate temperature of 1290± 10°C was found to be optimum for β-SiC epilayer nucleation and growth. The maximum β-SiC epitaxial growth rate obtained was 10μms/hr. Undoped β-SiC epilayers were n-type (n≈1016 cm−3 ). DSE synthesis, CVD growth parameters, SiC deposition characteristics and β-SiC epitaxial film properties are described.
The residual stress in a 6H-SiC wafer with a 3C-SiC epitaxial overlayer is determined by the technique of Synchrotron white beam x-ray topography (SWBXT). The short wavelength and high energy attributes of synchrotron radiation are exploited to very accurately determine the wafer curvature. Different approaches including absorption edge contour (AEC) mapping, multiple diffraction line (MDL) analysis and diffracted x-ray beam divergence (DXBD) analysis in both transmission and reflection geometry are demonstrated. The residual stress distribution is calculated from the wafer curvature measurement.
Color phosphors have been deposited on indium-tin glasses by utilizing an electrophoretic process for the application to prototype 4-inch full color FED devices. The deposition suspension is prepared with color phosphors of l-3um size, isopropanol, charger and binder. Various parameters, such as deposition time and applied voltages, are systematically performed to this end. As a result, each phosphor exhibited uniform thickness of about 6–10um over the whole plate. Electrical properties of the deposited phosphors are investigated and compared both in the vacuum chamber and in fully-sealed 4” FED conditions. In addition, they are extensively characterized by the SEM and 3-dimentional analysis. Experimental results confirm that the phosphor quality in real FED devices is significantly affected by deposition conditions.
A CdZnTe strip detector large area array (∼ 60 cm2 with 36 detectors) with capabilities for high resolution imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. The detector array also has applications in nuclear medical imaging. Two dimensional orthogonal strip detectors with 100 gm pitch have been fabricated and tested. Details for the array design, fabrication and evaluation of the detectors will be presented.
The widespread use of pigmented color filters in the AMLCD industry has focused attention on their deficiencies, which include marginal film transmittance, significant depolarization and generally poor imaging characteristics for the corresponding imaging resists. These limitations result in diminished color filter contrast and curtailed brightness for the AMLCD device. Incremental color filter contrast improvements have been generated through use of smaller pigment particles which reduce, but do not eliminate, light scattering. As standard pigment synthetic and grind processes give only small color contrast gains, at a cost of protracted pigment manufacture time, another route to more significant gains in color filter contrast is probably necessary. The work herein describes our attempt at defining one viable approach to real improvements in the key color filter responses of reduced depolarization and improved color contrast.
Our approach employs colorants prepared from colloidal suspensions of nanosized, mono-dispersed, dense silica spheres to which appropriate red, green and blue dyes are sorbed. Subsequent dispersion of each colorant nanocomposite in carrier polymer and photoimaging chemistry yields the corresponding negative-tone red, green and blue imageable photoresist. The synthesis and use of monodispersed colorant colloids has been described by Giesche and Matijevic for this and other related areas, but their utility is limited to applications not addressing the more advanced color filter requirements mentioned above. To those ends, our work focused on the synthesis, formulation and optical testing of nanocomposite colorant particles ranging from 10–30 nm in size, using dye chemistry which bridges compatibility between both silica nanosphere and carrier polymer, resulting in clear, highly transparent color films. Two independent optical tests comparing the color contrast on nanocomposite red films with coatings of similar transmittance prepared from reference red pigment dispersion provided rationalization that light scattering is significantly reduced in the nanocomposite film, as evidenced by the 3–10 fold increase in the color contrast ratios.
Zn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.
We present performance results of 4-inch full-color field emission display (FED) devices which are constructed by using Spindt type arrays with 80,000,000 Mo-metal tips, spacers, uniquely-developed low voltage color phosphors. Spindt type microtips with less than 1.1 urn in hole size are fabricated using a total internal reflection (TIR) holographic lithograpy method. Each color phosphor is electrophoretically deposited on the ITO line. The spacer which is screen-printed is characterized by a 3-dimentional surface analysis system. Electron emission pattern and luminance test of each pixel without cross talk are analyzed under different gate voltages. In addition, the total pressure and residual gas distributions inside the panel are investigated at various gap sizes between the cathode and anode plates.
A CdZnTe strip detector large area array (∼ 60 cm2 with 36 detectors) with capabilities for high resolution imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. The detector array also has applications in nuclear medical imaging. Two dimensional orthogonal strip detectors with 100 μm pitch have been fabricated and tested. Details for the array design, fabrication and evaluation of the detectors will be presented.