Air sampling methods for s-tetrachloroethane and other related chlorinated hydrocarbons

An acid-treated Pittsburgh Activated Carbon (PAC) tube for sampling s-tetrachloroethane in air is described that minimizes sample losses through dehydrogenation and dehydrohalogenation reactions. Commercially prepared NIOSH characoal, untreated PAC, and acid-treated PAC tubes are compared as to their effectiveness in stabilizing s-tetrachloroethane. Common homologues and analogues of s-tetrachloroethane cause no interference with the gas chromatographic method. -n addition the effectiveness of the untreated PAC and acid-treated PAC tubes was also evaluated for four different chlorinated aliphatic hydrocarbons.     

Heat transfer between fish and ambient water

A theoretical model is developed to predict pressure changes and velocity profiles within the foetal lung during its sporadic bursts of activity. Because of the small volume flow rates and relatively high frequencies, the linearised, unidirectional Navier-Stokes equations are used to calculate these values. About 70% of the pressure drop occurs in the first four generations and is an order of magnitude higher than the equivalent Poiseuille pressure drop. Velocity profiles, pressure falls within each generation together with the total pressure drop at different times during the cycle are illustrated.     

Inhibition of HIV-1 gp160-dependent membrane fusion by a furin-directed alpha 1-antitrypsin variant

Furin is a membrane-associated calcium-dependent serine endoprotease that cleaves proproteins on the carboxyl side of the consensus sequence -Arg-X-Lys/Arg-Arg-. Using site-directed mutagenesis, a variant alpha 1-antitrypsin (alpha 1-AT) was constructed which contains in its reactive site -Arg-X-X-Arg-, the minimal sequence required for efficient processing by furin (Molloy, S. S., Bresnahan, P. A., Leppla, S. H., Klimpel, K. R., and Thomas, G. (1992) J. Biol. Chem. 267, 16396-16402). This alpha 1-AT variant, [Arg355 Arg358]alpha 1-AT (alpha 1-PDX), is greater than 3,000-fold more effective than [Arg358]alpha 1-AT (alpha 1-AT Pittsburgh, alpha 1-PIT) at inhibiting furin in vitro (K0.5 = 0.03 microgram/ml). Furthermore, the P4 Arg in alpha 1-PDX greatly attenuates the thrombin inhibitory properties of this serpin (> 300-fold) compared with alpha 1-PIT (which contains a P4 Ala), thus increasing the selectivity of alpha 1-PDX for furin. Expression studies show that alpha 1-PDX, and not alpha 1-PIT, blocks the processing of two furin substrates, pro-beta-nerve growth factor and human immunodeficiency virus (HIV)-1 gp160 in transfected cells. In addition, a syncytium assay shows that alpha 1-PDX blocks the membrane fusogenic properties of HIV-1 gp160. The potential use of alpha 1-PDX in manipulating the activation of proproteins in a tissue- and time-specific manner is discussed.     

Beyond relevance--characteristics of key papers for clinicians: an exploratory study in an academic setting

OBJECTIVE: The purpose of this study was to determine what factors beyond relevance influence a clinician's decision to choose to read one journal article over another in satisfying an information need. DESIGN: Seventeen health care providers were interviewed and then surveyed regarding the characteristics of key articles (those they would not want to miss). On a Likert scale, the clinicians graded forty-two characteristics for importance in the decision process. Relevance was assumed and not at issue. SETTING: The study took place in an academic health science center. SUBJECTS: The subjects were seventeen clinicians, all with patient care responsibilities. There were four internists, four surgeons, three family practitioners, three pediatricians, two psychiatrists, and one clinical psychologist. RESULTS: Factors beyond relevance that most often influenced the decision process pertained to methodological rigor, authors and their institutional affiliations, document types, and population studied. CONCLUSIONS: Among the clinicians surveyed, factors beyond topicality influenced judgments as to what constitutes an important article. The emphasis respondents gave to certain attributes is echoed in other published work and highlights the need for more intensive investigation of these non-subject indicators as search parameters. Improved searching capabilities might well lead to a significant reduction in the clinician's information overload.     

Long-term placement of dependent children from the client's point of view

This article presents data regarding the backgrounds and attitudes of 396 dependent children in Israel who had been living in boarding institutions for almost three years, and were at least 10 years old at the time of the research interview. Parents of the children were also interviewed, and background [corrected] information regarding the family and its experience with placement was abstracted from welfare department records. This detailed information, collected nearly a decade ago, was then compared with several very recent Israeli studies of institutionalized dependent children and it was found that many problematic features of placement still persist. Among these are lack of long or short-term planning by welfare agencies, poor agency follow-up after placement, and little personal contact with either the child or his family. More older children were accepting placement than were younger children, and the majority of the parents did not contemplate the child's return home, being quite satisfied with placement in the institution. The findings from this study should have direct implications for child welfare policy and practices.     

PGM3 locus and its genetic polymorphism in lymphocytes of the pig

PGM3 activity was investigated by means of horizontal starch gel electrophoresis. In the pig of the German Landrace three different phenotypes have been recognized: F, S and FS. Family studies suggest the occurrence of at least two alleles--PGM3F and the PGM3S at an autosomal locus.