John van Genderen

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A speech of then-Vice President Al Gore in 1998 created a vision for a Digital Earth, and played a role in stimulating the development of a first generation of virtual globes, typified by Google Earth, that achieved many but not all the elements of this vision. The technical achievements of Google Earth, and the functionality of this first generation of(More)
We report the isolation, on a 0.1- to 2-mg scale, of the four stereoisomers of the nerve agent pinacolyl methylphosphonofluoridate (soman), assigned as C(+)P(+), C(+)P(-), C(-)P(+), and C(-)P(-), with more than 99% optical purity. This result was realized by means of (i) complete optical resolution of pinacolyl alcohol, (ii) synthesis of C(+)- and(More)
The four stereoisomers of the nerve agent pinacolyl methylphosphonofluoridate (soman), designated as C(+)P(+), C(+)P(-), C(-)P(+), and C(-)P(-), have different toxicologic properties due to stereospecific interactions in living organisms. We report the isolation of these stereoisomers with more than 99% optical purity. This result was realized by means of(More)
The relative exposure from drinking water is generally small, although there is a lack of information on total daily intake of individual organic micropollutants. There are, however, a few exceptions. Materials used in domestic distribution systems (lead, copper and plastics) may cause a deterioration of the water quality, especially in stagnant water. The(More)
Ongoing pollution and improving analytical techniques reveal more and more anthropogenic substances in drinking water sources, and incidentally in treated water as well. In fact, complete absence of any trace pollutant in treated drinking water is an illusion as current analytical techniques are capable of detecting very low concentrations. Most of the(More)
Because of the lack of agreement about the effects of topically applied antiviral agents on herpes simplex virus (HSV) skin infections in humans and in animals, an in-vivo human skin model of infection was developed. Human skin was grafted on to congenitally athymic nude mice and the therapeutic effects of topically applied viral DNA polymerase inhibitor(More)
The extrapolation of the results of measurements of skin penetration or skin damage with current in vitro and in vivo animal models to humans is of questionable value. Therefore, the usefulness of two other models is being evaluated: human skin grafts on congenitally athymic mice and cultures of human epidermal cells. The results show that histologically(More)
The fate of the four stereoisomers of soman [C(-)P(+), C(+)P(+), C(+)P(-) and C(-)P(-)] was studied by incubating 10 microM C(+/-)P(+/-)-soman at pH 7.4 and 37 degrees for various periods in the presence or absence of homogenates (1:10 and 1:20 w/v) of guinea-pig, mouse or human skin. The remaining concentrations of the soman isomers were determined gas(More)
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