Measurement of Internal Carotid Artery Blood Volume Pulsations by Noncontact Ocular Photoelectric Plethysmography

The goal of this investigation is to develop a noninvasive technique to assess the patency of the internal carotid artery. A noncontact photoelectric plethysmograph was designed to measure intraocular blood volume pulsations. This technique is appropriate for an evaluation of carotid stenosis since the ophthalmic artery is a branch of the internal carotid. With this noncontact instrument a beam of light is passed from a photoelectric system through the pupil. Light is reflected from the retinal and choroidal vasculature and is detected by a photodetector. This instrument has been used successfully in a series of experiments with pigmented and albino rabbits. The results demonstrate that the instrument measures the light reflected from the intraocular vasculature by the following observations: 1) an occlusion of the ca-rotid artery causes a disappearance of the ocular pulse; and 2) the amplitude of the ocular pulse is smaller in the pigmented rabbit when compared with the albino rabbit. Ocular movement artifacts and low reflected signal amplitude (due to light absorption by the retinal pigment) may necessitate the use of signal analysis techniques in patient studies.     

Replacement of cysteine-107 of Saccharomyces cerevisiae iso-1-cytochrome c with threonine: improved stability of the mutant protein

Site-directed mutagenesis has been used to change the codonfor cysteine-107 of Saccharomyces cerevisiae iso-1-cytochromec to a threonine codon. The resulting protein is active in vivo,is methylated as in the wild-type protein and has optical propertiesindistinguishable from those of the wild-type protein. The threonine-107iso-1-cytochrome c demonstrated fully reversible electrochemicalbehaviour and a mid-point reduction potential of 272 mV versusNHE. In addition, this mutant does not demonstrate a tendencyto autoreduce or to dimerize as does the wild-type protein.These properties of the threonine-107 mutant establish thatit will provide a useful background in which to make subsequentmutations for mechanistic and physical studies of yeast iso-1-cytochromec.     

Synthesis, Sintering, Microstructure, and Mechanical Properties of Ceramics Made by Exothermic Reactions

Al₂O₃-TiC, Al₂O₃-TiC_0.5N_0.5, Al₂O₃-WC, Al₂O₃-SiC, and Al₂O₃-HfB₂ powders were synthesized by the aluminothermic reduction of oxides in the presence of carbon or boron. The reacted powders were milled to reduce the size of agglomerates and subsequently densified without applied pressure to near-theoretical density. Microstructures and mechanical properties of composites made from exothermically reacted powders were compared with similar ceramics made from commercially available powders. In situ sintering was possible in the Al₂O₃-TiC system using a closed graphite crucible to contain reaction gases. The synthesis of β -SiC at temperatures above 1400°C via the direct reaction of the elements (SHS) was compared with SiC made by the magnesiothermic reduction of SiO₂ in the presence of C after removing the MgO by leaching.     

Anticipatory dementia: a link between memory appraisals and concerns about developing Alzheimer's disease

This exploratory study examines the link between memory appraisals and personal concerns about developing Alzheimer's disease. The sample of persons ages 40-60 includes adult children with a living parent who has Alzheimer's disease (N = 25) and a matched group with no family history of dementia (N = 25). Using two composite measures of memory appraisals, the results show significant bivariate and multivariate relationships between self-assessments of memory functioning and concerns about developing the disease. The findings also suggest that negative memory appraisals evoke concerns about developing Alzheimer's disease within both of the subsamples.     

Scratch filter using c.c.d.s

This letter describes the use of charge-coupled devices in the automatic real-time editing of audio signals. A simple semiconductor device is used to replace a number of complex digital circuits.     

Designing Tomorrow's Innovation

Chair to the Australian government's Review of the National Innovation System in 2008, Terry Cutler is an industry consultant and strategy advisor with a background in the information and communications technology sector. Here, he opens up the question of architectural innovation to the wider context of the economy and social need. If architects are to innovatively address pressing social and environmental issues, such as climate change, obesity, population ageing and resource depletion, how does the architect's role need to be reformulated?     

Functional phase grading of ζ-Ta4C3-x: Kinetics and properties

Phase-graded carbides that exhibit high hardness and corrosion resistance on the surface and high fracture toughness in the bulk are useful in severe wear applications. A method for producing hard γ-TaC_y layer on the surface of a tough ζ-Ta₄C_3-x substrate by carburization is described in this study. The γ-TaC_y layer exhibited parabolic growth kinetics in the temperature and gas-flow regimes investigated in this study. Analyses of the rate constants using a model of mass transport through two phases in equilibrium at the interface indicated diffusion of carbon through the product layer was the rate-controlling step with diffusivities (1-5 × 10⁻¹⁵ m²/s in the 1623-1773K range) and enthalpy (213-217 kJ/mol) matching those for carbon diffusion in γ-TaC_y. Nanohardness of the transformed γ-TaC_y layer increased as a function of distance from the carburized surface, with a maximum hardness occurring near the γ/ζ interface. Measurements of lattice parameters at different depths in the γ-TaC_y layer indicated that the hardness increase with depth was related to the increasing carbon deficiency of the γ-TaC_y phase through the thickness.     

Anti-CD40 ligand antibody treatment of SNF1 mice with established nephritis: preservation of kidney function

Prior studies have demonstrated that treatment of young, prenephritic lupus-prone mice with Ab directed against CD40 ligand (CD40L) prolongs survival and decreases the incidence of severe nephritis. In this report, we show that for (SWR x NZB)F1 (SNF1) animals with established lupus nephritis, long-term treatment with anti-CD40L beginning at either 5.5 or 7 mo of age prolonged survival and decreased the incidence of severe nephritis. "Older" mice were chosen for these studies to more closely resemble the clinical presentation of patients with established renal disease. We show that age at the start of treatment, which typically correlates with severity of disease, is an important factor when determining an efficacious therapeutic protocol since animals that began treatment at 7 mo of age required a more aggressive treatment protocol than animals at 5.5 mo of age. Remarkably, several anti-CD40L-treated animals beginning treatment at age 5.5 mo demonstrated a decline in proteinuria, as opposed to increasing proteinuria levels seen in hamster IgG (HIg)-treated controls, and histologic examination of kidneys from anti-CD40L-treated mice revealed dramatically diminished inflammation, sclerosis/fibrosis, and vasculitis, in marked contrast to the massive inflammation and kidney destruction observed in control animals that received hamster IgG. Spleens from anti-CD40L-treated mice also exhibited markedly reduced inflammation and fibrosis compared with controls. Together, these results show that treatment of older, nephritic SNF1 animals with long-term anti-CD40L immunotherapy significantly prolongs survival, reduces the severity of nephritis, and diminishes associated inflammation, vasculitis, and fibrosis.