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Biomedical subjects

James J Corbett

Publications and source records attributed to James J Corbett.

13 recordsLinked to original sources
PubMed2006

An environmental decision framework applied to marine engine control technologies.

This paper develops a decision framework for considering emission control technologies on marine engines, informed by standard decision theory, with an open structure that may be adapted by operators with specific vessel and technology attributes different from those provided here. Attributes relate objectives important to choosing control technologies with specific alternatives that may meet several of the objectives differently. The transparent framework enables multiple stakeholders to understand how different subjective judgments and varying attribute properties may result in different technology choices. Standard scoring techniques ensure that attributes are not biased by subjective scoring and that weights are the primary quantitative input where subjective preferences are exercised. An expected value decision structure is adopted that considers probabilities (likelihood) that a given alternative can meet its claims; alternative decision criteria are discussed. Capital and annual costs are combined using a net present value approach. An iterative approach is advocated that allows for screening and disqualifying alternatives that do not meet minimum conditions for acceptance, such as engine warranty or U.S. Coast Guard requirements. This decision framework assists vessel operators in considering explicitly important attributes and in representing choices clearly to other stakeholders concerned about reducing air pollution from vessels. This general decision structure may also be applied similarly to other environmental controls in marine applications.

Air Pollutants↗
PubMed2005

Optimal fleetwide emissions reductions for passenger ferries: an application of a mixed-integer nonlinear programming model for the New York-New Jersey Harbor.

Emissions from passenger ferries operating in urban harbors may contribute significantly to emissions inventories and commuter exposure to air pollution. In particular, ferries are problematic because of high emissions of oxides of nitrogen (NOx) and particulate matter (PM) from primarily unregulated diesel engines. This paper explores technical solutions to reduce pollution from passenger ferries operating in the New York-New Jersey Harbor. The paper discusses and demonstrates a mixed-integer, non-linear programming model used to identify optimal control strategies for meeting NOx and PM reduction targets for 45 privately owned commuter ferries in the harbor. Results from the model can be used by policy-makers to craft programs aimed at achieving least-cost reduction targets.

Air Pollutants↗
PubMed2004

Normalization of cerebrospinal fluid abnormalities after neurosyphilis therapy: does HIV status matter?

To identify factors that affect normalization of laboratory measures after treatment for neurosyphilis, 59 subjects with neurosyphilis underwent repeated lumbar punctures and venipunctures after completion of therapy. The median duration of follow-up was 6.9 months. Stepwise Cox regression models were used to determine the influence of clinical and laboratory features on normalization of cerebrospinal fluid (CSF), white blood cells (WBCs), CSF protein concentration, CSF Venereal Disease Research Laboratory (VDRL) reactivity, and serum rapid plasma reagin (RPR) titer. Human immunodeficiency virus (HIV)-infected subjects were 2.5 times less likely to normalize CSF-VDRL reactivity than were HIV-uninfected subjects. HIV-infected subjects with peripheral blood CD4+ T cell counts of < or =200 cells/ mu L were 3.7 times less likely to normalize CSF-VDRL reactivity than were those with CD4+ T cell counts of >200 cells/ mu L. CSF WBC count and serum RPR reactivity were more likely to normalize but CSF-VDRL reactivity was less likely to normalize with higher baseline values. Future studies should address whether more intensive therapy for neurosyphilis is warranted in HIV-infected individuals.

Anti-Bacterial Agents↗
PubMed2004

Cerebrospinal fluid abnormalities in patients with syphilis: association with clinical and laboratory features.

OBJECTIVE: To define clinical and laboratory features that identify patients with neurosyphilis. METHODS: Subjects (n=326) with syphilis but no previous neurosyphilis who met 1993 Centers for Disease Control and Prevention criteria for lumbar puncture underwent standardized history, neurological examination, venipuncture, and lumbar puncture. Neurosyphilis was defined as a cerebrospinal fluid (CSF) white blood cell count >20 cells/ microL or reactive CSF Venereal Disease Research Laboratory (VDRL) test result. RESULTS: Sixty-five subjects (20.1%) had neurosyphilis. Early syphilis increased the odds of neurosyphilis in univariate but not multivariate analyses. In multivariate analyses, serum rapid plasma reagin (RPR) titer > or =1 : 32 increased the odds of neurosyphilis 10.85-fold in human immunodeficiency virus (HIV)-uninfected subjects and 5.98-fold in HIV-infected subjects. A peripheral blood CD4+ T cell count < or =350 cells/ microL conferred 3.10-fold increased odds of neurosyphilis in HIV-infected subjects. Similar results were obtained when neurosyphilis was more stringently defined as a reactive CSF VDRL test result. CONCLUSION: Serum RPR titer helps predict the likelihood of neurosyphilis. HIV-induced immune impairment may increase the risk of neurosyphilis.

Adolescent↗
PubMed2004

Isotretinoin-associated intracranial hypertension.

PURPOSE: To evaluate the association between intracranial hypertension (IH) and isotretinoin use. DESIGN: Observational case series. METHODS: In this retrospective study, approximately 1950 case reports of adverse ocular side effects related to isotretinoin were received from spontaneous reporting systems. Reports were evaluated as to the occurrence of IH with isotretinoin use. A survey was mailed to all members of the North American Neuro-ophthalmology Society soliciting their opinions on whether isotretinoin caused IH. RESULTS: One hundred seventy-nine reports of IH were associated with isotretinoin use. The mean time from drug exposure to IH diagnosis was 2.3 months. There were 6 cases of positive rechallenge; 5 new cases are reported here, along with 1 previously published report. Of neuro-ophthalmologists surveyed (62% response rate), 6% believed an association between IH and isotretinoin use was certain; 32%, probable; 52%, possible; and 10%, unlikely. Twelve respondents (4%) had personally seen one or more cases of positive rechallenge with isotretinoin causing IH. CONCLUSIONS: Based on the number and pattern of rapid IH onsets after isotretinoin exposure and the 6 cases of positive rechallenge, along with the probable similarity in metabolic pathways of this agent and vitamin A (a known cause of IH), it seems certain that there is a direct correlation between IH and isotretinoin use.

Adolescent↗
PubMed2004

Visual dysfunction caused by gauze wrapping of an intracranial aneurysm.

A 43-year-old woman developed right frontal headache and decreased vision in her OD 14 months after treatment of an intracranial aneurysm by wrapping with cotton gauze. A junctional visual field defect was present, and an MRI revealed a contrast-enhancing mass involving the right optic nerve, lateral chiasm, optic tract, and cavernous sinus. Biopsy demonstrated a marked inflammatory reaction mixed with strands of birefringent cotton gauze. Despite treatment with high-dose corticosteroids, visual loss progressed to bilateral blindness. This is the 30th reported case of an intracranial inflammatory tumor developing from a gauze-wrapped aneurysm ("gauzoma" or "muslinoma") and the worst reported visual outcome. Most cases have occurred in women and involved the optic nerves or chiasm. Visual improvement has sometimes occurred after treatment with abscess drainage, debulking, and/or corticosteroids. A rare complication of aneurysm wrapping, gauzomas causing visual loss have been reported up to 54 months after surgery.

Adult↗
PubMed2003

The bedside and office neuro-ophthalmology examination.

The neuro-ophthalmologic examination provides an enormous amount of information about the 40% of fibers that provide afferent and efferent limbs of the visual, pupillary, and ocular motor pathways. A few tools and the correct testing approach will maximize the value of this examination. This chapter provides step-by-step examination methods and points out some of the common errors that are made.

Color Perception↗
PubMed2002

Emissions from ships in the northwestern United States.

Recent inventory efforts have focused on developing nonroad inventories for emissions modeling and policy insights. Characterizing these inventories geographically and explicitly treating the uncertaintiesthat result from limited emissions testing, incomplete activity and usage data, and other important input parameters currently pose the largest methodological challenges. This paper presents a commercial marine vessel (CMV) emissions inventory for Washington and Oregon using detailed statistics regarding fuel consumption, vessel movements, and cargo volumes for the Columbia and Snake River systems. The inventory estimates emissions for oxides of nitrogen (NOx), particulate matter (PM), and oxides of sulfur (SOx). This analysis estimates that annual NOx emissions from marine transportation in the Columbia and Snake River systems in Washington and Oregon equal 6900 t of NOx (as NO2) per year, 2.6 times greater than previous NO, inventories for this region. Statewide CMV NO, emissions are estimated to be 9,800 t of NOx per year. By relying on a "bottom-up" fuel consumption model that includes vessel characteristics and transit information, the river system inventory may be more accurate than previous estimates. This inventory provides modelers with bounded parametric inputs for sensitivity analysis in pollution modeling. The ability to parametrically model the uncertainty in commercial marine vessel inventories also will help policy-makers determine whether better policy decisions can be enabled through further vessel testing and improved inventory resolution.

Air Pollutants↗
PubMed2002

Controlling air pollution from passenger ferries: cost-effectiveness of seven technological options.

Continued interest in improving air quality in the United States along with renewed interest in the expansion of urban passenger ferry service has created concern about air pollution from ferry vessels. This paper presents a methodology for estimating the air pollution emissions from passenger ferries and the costs of emissions control strategies. The methodology is used to estimate the emissions and costs of retrofitting or re-powering ferries with seven technological options (combinations of propulsion and emission control systems) onto three vessels currently in service in San Francisco Bay. The technologies include improved engine design, cleaner fuels (including natural gas), and exhaust gas cleanup devices. The three vessels span a range of ages and technologies, from a 25-year-old monohull to a modern, high-speed catamaran built only four years ago. By looking at a range of technologies, vessel designs, and service conditions, a sense of the broader implications of controlling emissions from passenger ferries across a range of vessels and service profiles is provided. Tier 2-certified engines are the most cost-effective choice, but all options are cost-effective relative to other emission control strategies already in place in the transportation system.

Air Pollution↗