Setting standards for improved syndromic surveillance

Clearly, there is a need for data at multiple levels and many locations. Investigations of possible cases and outbreaks must occur locally, and local data must be available as generated to healthcare providers and emergency responders. At the same time, regional, national and international authorities need aggregated data to understand the scope of an outbreak and to assist in the response. Thus, in comparison to a system in which data is sent to a central facility for aggregation and redistributed to local areas, we argue that a distributed system is much more appropriate and resilient to a bioterrorism event. The distributed data system can provide information to local responders for their immediate action and reduce demand on a central system and data unavailability over wide area networks while providing raw data immediately to centralized reviewers.     

APPLICATION AND USE OF THE ATR, FT-IR METHOD TO ASPHALT AGING STUDIES

Infrared analysis is an extremely valuable tool for investigating the chemical functionality of asphalts. The attenuated total reflection (ATR) FT-IR method is especially useful for the study of this intractable material. Quick and easy sample preparation, natural state analysis, and clean and reproducible spectra are advantages of the ATR method over conventional transmission methods. Comparisons of this procedure to potassium bromide pellet and solution methods support the method's use. Asphalt oxidative and solvent aging studies employed the ATR method to track hardening of asphalt in various solvents as indicated by increased carbonyl absorbances. Also. standard laboratory tests for simulating the hot-mix aging of asphalts, compared using this method as well as other chemical and physical properties, sbow significant differences from actual hot-mix aging     

Graft polymerization of acrylonitrile and methyl acrylate onto hemicellulose

Graft polymerizations of acrylonitrile onto both a commercial larchwood hemicellulose and a purified (low lignin) wheat straw hemicellulose could be initiated by ceric ammonium nitrate. The resulting hemicellulose-g-polyacrylonitrile (PAN) copolymers were fractionated by extraction at room temperature with dimethylformamide and dimethylsulfoxide. Fractions were characterized by determining both the wt % PAN in each polymer fraction and the molecular weight of grafted PAN. Saponification of the PAN component of hemicellulose-g-PAN gave a water-dispersible graft copolymer with good thickening properties for water systems. An absorbent polymer, similar to the starch-based absorbents (Super Slurpers), was produced when saponified hemicellulose-g-PAN was isolated by methanol precipitation and then dried. Larchwood hemicellulose was also graft-polymerized with methyl acrylate using ceric ammonium nitrate initiation, and the hemicellulose-g-poly(methyl acrylate) was extrusion-processed into a tough, leathery plastic. Although ceric ammonium nitrate could be used as an initiator for graft polymerizations onto low-lignin hemicelluloses, it was inert with crude wheat straw hemicellulose containing 11% lignin. The ferrous sulfate–hydrogen peroxide redox system was used to initiate graft polymerizations onto this high-lignin material, and properties of the resulting hemicellulose-g-poly(methyl acrylate) and saponified hemicellulose-g-PAN graft copolymers were evaluated.     

Graft polymerization of styrene onto starch by simultaneous cobalt-60 irradiation

Starch-g-polystyrene copolymers have been prepared by the simultaneous ⁶⁰Co-irradiation of starch–styrene mixtures, and copolymers have been characterized with respect to weight per cent polystyrene (% add-on) and also the molecular weight and molecular weight distribution of polystyrene grafts. In a typical polymerization, 4 g each of starch and styrene were blended with 1 ml water and 1.5 ml of an organic solvent; the resulting semisolid paste was irradiated to a total dose of 1 Mrad. With ethylene glycol, acetonitrile, ethanol, methanol, acetone, and dimethylformamide as the organic solvent, values for % add-on ranged from 24% to 29%. The highest % add-on (43%) and the highest conversion of styrene to grafted polymer (76%) were obtained when the organic solvent was omitted, and water alone was used. When water was also omitted, polymerization of styrene was negligible; however, graft copolymer was formed in the absence of water when either ethylene glycol or ethanol was added. Attempts were unsuccessful to achieve a % add-on greater than 43% by doubling the amount of styrene in the polymerization recipe. Mixtures of equal weights of starch and styrene are relatively nonvicious, but these mixtures thicken when either water or ethylene glycol is blended in. Reasons for this thickening action and the possible influence of thickening on the graft polymerization reaction were explored.     

Stress relaxation analysis and irradiation creep and swelling in pressure tubes

An analysis is presented of slit width test information on two pressure tubes that had been irradiated in test reactors. The analysis showed that differential swelling stresses and thermal stresses undergo relaxation. The mechanism responsible for the stress relaxation at temperatures less than 700 K was irradiation creep. Irradiation creep in thermal test reactor pressure tubes is evidently greater than it would be at equivalent conditions in fast reactors. The residual stresses observed in the slit width tests varied between 30 and 257 MPa and would act to reduce the operating stresses, thus allowing for increased service life of the tubes as compared with no stress relaxation.     

Creatinine, calcium, citrate and acid-base in spinal cord injured patients

The aim of this work was to recognise factors responsible for reduced citrate excretion, previously reported in patients with spinal cord lesions and possibly related to the occurrence of urinary tract stone or catheter blockage. Inter alia, a reference range for creatinine in plasma (34-88 mumol/l) was also obtained. Two groups of subjects were studied. The first group consisted of 64 male inpatients with spinal cord lesions and 20 male control subjects. The second group were 342 spinal patients who attended an outpatient clinic and 31 control subjects. Plasma calcium was within the normal range but higher in patients within 1 year of onset of the cord lesion than it was later or than was found in control subjects. Plasma pH and bicarbonate were within the normal range but higher in the patients than in the control subjects. When patients with urea-splitting infection were omitted the patients had a higher urinary pH and a lower urinary ammonium than the controls. Urinary and plasma citrate were lower in the patients than in the controls. Urinary citrate was related to urinary potassium and creatinine clearance. Fractional renal tubular reabsorption of citrate did not differ between patients with normal renal function and control subjects. Patients with normal glomerular filtration had lower filtered load of citrate than the controls. The coincidence of relative alkalosis and reduced citrate excretion may be relevant to the understanding of catheter blockage and urinary stone formation in spinal cord injured patients.     

Pattern-reversal electroretinogram in response to chromatic stimuli: II. Monkey

We have recorded steady-state PERGs from five macaque monkeys in response to red-green plaid patterns reversed sinusoidally in contrast. The patterns had either a pure luminance contrast (red-black, green-black, yellow-black), pure red-green color contrast, or a variable amount of luminance and color contrast. By varying the relative luminance of the red-to-total luminance (color ratio) of red-green patterns, a value could be obtained at which the PERG amplitude was either minimum or locally maximum, and the phase was most lagged. This value was very similar to that producing equiluminance in human observers, and was considered to be equiluminance for the monkey. The phase of the PERG to chromatic stimulus was systematically lagged compared with that of luminance stimuli, by an amount corresponding to about 10-20 ms under our experimental conditions. The variation of phase with temporal frequency suggested an apparent latency of about 80 ms for color contrast compared with 63 ms for luminance. These estimates were confirmed with separate measurements of transient PERGs to abrupt contrast reversal. As a function of temporal frequency, the chromatic PERG function was clearly low-pass with a cutoff around 15 Hz, whereas that to luminance was double-peaked and extended to higher temporal frequencies, around 30 Hz. For both luminance and chromatic stimuli, the amplitude of PERGs increases with increasing stimulus contrast. By summing vectorially the luminance and chromatic responses of appropriate contrasts, we were able to predict with accuracy the response as a function of color ratio. In two monkeys, the optic chiasm was sectioned sagittally causing total degeneration of ganglion cells in the nasal retina, without affecting the temporal retina (verified by histology). In these animals, there was a strong response to both luminance and chromatic patterns in the temporal retinae, but none to either type of pattern in the nasal retinae, suggesting that the PERG to both luminance and chromatic stimuli arises from the inner-retinal layers. Electrophysiological studies suggest that the PERG to chromatic stimuli is probably associated with the activity of P-cells. P-cells may also make a major contribution to the PERG of luminance stimuli, although M-cells may also participate. The above findings on normal monkeys all agree with those reported in the accompanying paper for humans (Morrone et al., 1994), so similar conclusions can probably be extended to human PERG.