Urban environmental health applications of remote sensing

An urban area was studied through the use of the inventory-by-surrogate method rather than by direct interpretation of photographic imagery. Prior uses of remote sensing in urban and public research are examined. The effects of crowding, poor housing conditions, air pollution, and street conditions on public health are considered. Color infrared photography was used to categorize land use features and the grid method was used in photo interpretation analysis. The incidence of shigella and salmonella, hepatitis, meningitis, tuberculosis, myocardial infarction and veneral disease were studied, together with mortality and morbidity rates. Sample census data were randomly collected and validated. The hypothesis that land use and residential quality are associated with and act as an influence upon health and physical well-being was studied and confirmed

Urban environmental health applications of remote sensing, summary report

Health and its association with the physical environment was studied based on the hypothesis that there is a relationship between the man-made physical environment and health status of a population. The statistical technique of regression analysis was employed to show the degree of association and aspects of physical environment which accounted for the greater variation in health status. Mortality, venereal disease, tuberculosis, hepatitis, meningitis, shigella/salmonella, hypertension and cardiac arrest/myocardial infarction were examined. The statistical techniques were used to measure association and variation, not necessarily cause and effect. Conclusions drawn show that the association still exists in the decade of the 1970's and that it can be successfully monitored with the methodology of remote sensing

Characterization of hyporheic zone processes of a northern prairie stream

A hyporheic zone occurs beneath and adjacent to streams where surface water and groundwater mix. This zone is known to be a reservoir for solutes and a habitat for interstitial organisms. Hyporheic zone boundaries in the Tongue River, North Dakota, were investigated through examination of the physicochemical and biological gradients present in the stream channel and bank sediments. The effects of cattle grazing at the streamside interface of the riparian zone were also examined at two locations to determine land use impacts on the hyporheic zone. Electrical conductivity (EC) and ammonium gradients were observed beneath the stream channel via nests of mini-piezometers (1.27-cm clear polyethylene tube) and wells (2.54-cm PVC). EC and ammonium increased immediately below the stream, then decreased laterally and with depth. Discontinuities in the EC gradient may indicate where metabolic or redox reactions occur under the streambed due to mixing of surface water and groundwater, or conditions in the sediments. Discontinuities in the ammonium gradient may represent a boundary between dissimilatory nitrate reduction to ammonium and a nitrification-denitrification couple, as well as subtle changes in hydraulic gradient. Discontinuities in gradients and zones beneath the stream channel likely fluctuate as subsurface processes shift temporally. Changes in biotic activity could have caused ammonium concentrations in sub-channel water to decrease from spring to summer and then increase from summer to fall at both sites. Chemical and biological gradients in the Tongue River differ from other studies presumably because of regional differences in geology, climate, and hydrology. The density and diversity of interstitial meiofauna populations may provide information about the general physical and chemical conditions of streambed sediments. Meiofauna diversity and population size decreased with ·depth at both study sites. High levels of ammonium and/or ambient reduced conditions in zones beneath the channel could exclude most meiofauna species. Meiofauna population dynamics also may indicate stream reach health. Cattle grazing in the riparian zone appeared to affect chemical and biological gradients. Ammonium concentrations and EC were elevated at the grazed site (\u3e10 mg/Land 1300 µSiem, respectively). The lack of riparian vegetation and direct input of cattle waste may have caused higher EC and ammonium at the stream margin of the grazed site. Less dense and diverse populations of meiofauna at the grazed site were likely caused by greater disturbance of the sediments, lack of woody debris and preferred substrate, and more reduced conditions in the channel sediments. Differences in ammonium concentrations in subchannel water between the sites were greater than differences in nitrate concentrations in surface water. This implies that sampling designed to evaluate stream health must consider all sources and reservoirs of pollutants, and cannot solely depend on surface water analysis

Glutathione-Mediated Neuroprotection Against Methylmercury Neurotoxicity in Cortical Culture is Dependent on MRP1

Methylmercury (MeHg) exposure at high concentrations poses significant neurotoxic threat to humans worldwide. The present study investigated the mechanisms of glutathione-mediated attenuation of MeHg neurotoxicity in primary cortical culture. MeHg (5 μM) caused depletion of mono- and disulfide glutathione in neuronal, glial and mixed cultures. Supplementation with exogenous glutathione, specifically glutathione monoethyl ester (GSHME) protected against the MeHg induced neuronal death. MeHg caused increased reactive oxygen species (ROS) formation measured by dichlorodihydrofluorescein (DCF) fluorescence with an early increase at 30 min and a late increase at 6 h. This oxidative stress was prevented by the presence of either GSHME or the free radical scavenger, trolox. While trolox was capable of quenching the ROS, it showed no neuroprotection. Exposure to MeHg at subtoxic concentrations (3 μM) caused an increase in system xc− mediated 14C-cystine uptake that was blocked by the protein synthesis inhibitor, cycloheximide (CHX). Interestingly, blockade of the early ROS burst prevented the functional upregulation of system xc−. Inhibition of multidrug resistance protein-1 (MRP1) potentiated MeHg neurotoxicity and increased cellular MeHg. Taken together, these data suggest glutathione offers neuroprotection against MeHg toxicity in a manner dependent on MRP1-mediated efflux

The soft-x-ray spectral shape of x-ray-weak seyferts

(I) We observed eight Seyfert~2s and two X--ray--weak Seyfert~1/QSOs with the ROSAT PSPC, and one Seyfert~2 with the ROSAT HRI. These targets were selected from the Extended 12\um\ Galaxy Sample. (II) Both Seyfert~1/QSOs vary by factors of 1.5---2. The photon indices steepen in the more luminous state, consistent with the variability being mainly due to the softest X--rays, which are confined to a size of less than a parsec. (III) Both the Seyfert~2s and Seyfert~1/QSOs are best fit with a photon index of \Gamma\sim3, which is steeper than the canonical value of \Gamma\sim1.7 measured for X--ray--strong Seyferts by ROSAT and at higher energies. Several physical explanations are suggested for the steeper slopes of X--ray--weak objects. (IV) We observed one Seyfert~2, NGC~5005, with the ROSAT HRI, finding about 13\% of the soft X--rays to come from an extended component. This and other observations suggest that different components to the soft X--ray spectrum of some, if not all, X--ray--weak Seyferts may come from spatially distinct regions

Outcomes of Infectious versus Sterile Perforated Corneal Ulcers after Therapeutic Penetrating Keratoplasty in the United States

Purpose. To compare the long-term outcomes of infectious versus sterile perforated corneal ulcers after therapeutic penetrating keratoplasty in the United States. Methods. The charts of 45 consecutive eyes that underwent primary therapeutic penetrating keratoplasty for a perforated corneal ulcer at a single center were retrospectively reviewed. The perforated ulcers were classified as infectious or sterile and the underlying demographics, clinical features, and 36-month outcomes were compared among the two groups. Results. Mean follow-up among subjects was 38.6 (±6.9) months. Patients presenting with sterile perforated ulcers were more likely to have a peripheral perforation location (p=0.0333) and recurrence of the underlying disease condition (p=0.0321), require adjunctive surgical measures in the immediate postoperative period (p<0.0001), have reperforation after keratoplasty (p=0.0079), have worse best corrected visual acuity (p=0.0130), develop no light perception vision (p=0.0053), and require enucleation/evisceration (p=0.0252) when compared to the infectious perforated ulcer group. Conclusions. Sterile perforated corneal ulcers have a worse prognosis and may be more frequent than those caused by infectious disease in the United States compared to the developing world

Evaluation of Idiopathic Choroidal Neovascularization with Indocyanine Green Angiography in Patients Undergoing Bevacizumab Therapy

Purpose. To examine the clinical implications of change in choroidal neovascularization (CNV) size on indocyanine green (ICG) angiography in subjects with idiopathic CNV undergoing bevacizumab therapy. Methods. The charts of subjects with an idiopathic CNV treated by a modified PRN regimen with intravitreal bevacizumab over a 12-month period were retrospectively reviewed. Results. There were 34 subjects included in the analysis. Baseline CNV sizes of less than 1.0 mm2 on ICG angiography correlated with complete CNV resolution (P=0.0404), fewer injections delivered (P=0.0002), and better Snellen visual acuity (P=0.0098) at 12 months. Subjects that experienced a 33% or more reduction in CNV size on ICG angiography at 2 months had complete CNV resolution (P=0.0047) and fewer injections (P<0.0001) at 12 months compared to subjects that did not experience a 33% or more reduction in CNV size on ICG angiography at 2 months. Conclusions. Smaller baseline CNV size on ICG angiography resulted in better visual acuity and fewer injections at 12 months, and a reduction of 33% or more in CNV size after 2 months may predict a better clinical course in subjects with idiopathic CNV undergoing bevacizumab therapy