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Biomedical subjects

P S Porter

Publications and source records attributed to P S Porter.

16 recordsLinked to original sources
PubMed2001

Ozone air quality over north america: part II--an analysis of trend detection and attribution techniques.

Assessment of regulatory programs aimed at improving ambient O3 air quality is of considerable interest to the scientific community and to policymakers. Trend detection, the identification of statistically significant long-term changes, and attribution, linking change to specific climatological and anthropogenic forcings, are instrumental to this assessment. Detection and attribution are difficult because changes in pollutant concentrations of interest to policymakers may be much smaller than natural variations due to weather and climate. In addition, there are considerable differences in reported trends seemingly based on similar statistical methods and databases. Differences arise from the variety of techniques used to reduce nontrend variation in time series, including mitigating the effects of meteorology and the variety of metrics used to track changes. In this paper, we review the trend assessment techniques being used in the air pollution field and discuss their strengths and limitations in discerning and attributing changes in O3 to emission control policies.

Air Pollutants↗
PubMed2001

Ozone air quality over North America: part I--a review of reported trends.

Ozone and precursor trends can be used to measure the effectiveness of regulatory programs that have been implemented. In this paper, we review trends in the concentrations of O3 NOx, and HCs over North America that have been reported in the literature. Although most existing trend studies are confounded by meteorological variability, both the raw data trends and the trends adjusted for meteorology collectively indicate a general decreasing trend in O3 concentrations in most areas of the United States during 1985-1996. In Canada, mean daily maximum 1-hr O3 concentrations at urban sites show mixed trends with a majority of sites showing an increase from 1980 to 1993. Mean daily maximum 1-hr O3 at most regionally representative Canadian sites appears to decrease from 1985 to 1993 or shows no significant change. There are far fewer data and analyses of NOx and HC trends. Available studies covering various ranges of years indicate decreases in ambient NO and HC concentrations in Los Angeles, CA, decreases in HC concentrations in northeastern U.S. cities, and decreases in NOx concentrations in Canadian cities. Two key needs are long-term HC and NOx measurements, particularly at rural sites, and a systematic comparison of trend detection techniques on a reference data set.

Air Pollution↗
PubMed1980

Nertherton's syndrome.

A case of Netherton's syndrome is reported herein and twenty-four previous cases reviewed and tabulated with respect to age, sex, family history, intelligence, consanguinity, aminoaciduria, atopy, recurrent infections, and IgG. This syndrome is characterized by the presence of trichorrhexis invaginata, a distinctive hair shaft abnormality, and either ichtyosis linearis circumflexa or congenital ichthyosiform erythroderma. Recent investigations have shed light upon the pathogenesis of this disease but the precise structural, biochemical, and genetic abnormalities have not been elucidated.

Child↗
PubMed1971

Keratosis.

Explore the source record for details and available documents.

Foot Dermatoses↗
PubMed1971

The genetics of human hair growth.

The regulation of human hair growth is one of the most mysterious of biologic events. Genetic factors are responsible for the density, length, color and texture of hair. Heredity disorders can affect either hair alone, hair and other ectodermal structures, or can be pansystemic. This paper considers all heredity disorders which affect human hair growth. These disorders are divided into three categories: 1) the dysmorphic syndromes; 2) the modifier gene abnormalities and 3) the single major gene abnormalities. The disorders in these categories are listed, along with the mode of inheritance, cause, hair phenotype and the extent of involvement. The utilitarian function of the study of human hair growth is illustrated. Insight into problems of differentiation can be most rapidly expanded using this approach.

Abnormalities, Multiple↗
PubMed1965

Recent advances in the understanding of the penicillin urticarias.

The three major groups of immunoglobulins (gamma G, gamma A, and gamma M) associated with this disease are reviewed. The presence or absence of atopic disease may account for percentage variability of gamma A because reagins (skin-sensitizing antibodies) are found in this immunoglobulin. The gamma A is the antibody usually responsible for anaphylaxis, rather than the gamma G precipitins, so stressed in the past. All three immunoglobulins may be found in serum sickness, which could account for the complex nature of this type of penicillin urticaria. The merits of the immunological tests (penicilloyl-polylysine, benzyl penicillin, hemagglutination, basophil degranulation) for the detection of penicillin sensitivity are analyzed, particularly as each applies to the various types of penicillin urticaria (serum sickness, anaphylactic, dermographic, delayed dermographic, and simple chronic urticaria and the lupus diathesis). The penicilloyl-polylysine test is greatly overrated as a means of predicting possible anaphylaxis. The benzyl penicillin skin test properly performed is an excellent means of indicating this.

Humans↗