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1.
Biomed Sci Instrum ; 37: 191-6, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11347387

RESUMO

The primary objective of this research is to examine the feasibility of using an innovative technique based on laser-induced fluorescence coupled with flow cytometry to detect pathogenic microorganisms in food or water in real time. Our initial application is the rapid detection of E. coli O157:H7 in ground beef. The research performed demonstrated conclusively that this approach is feasible, and that the technique has key advantages over current alternatives including: it is (1) able to totally examine a large volume of food or water in real time, (2) capable of detecting single microorganisms (alternative techniques require in excess of 10(4) microorganisms), (3) intrinsically automatic, and (4) sensitive only to the selected bacteria. We have demonstrated the feasibility of detecting individual E. coli bacteria with a breadboard system. The performance of this system allows for rapid detection of individual specific pathogenic microorganisms. Two of the most significant commercial applications of this technique are the detection of infectious microorganisms in contaminated food and water. Food-borne microbial pathogens account for approximately 7 million illnesses and 9,000 deaths in the U.S. annually, with an estimated economic loss of at least $6 billion [1]. In addition, this method has the potential for a broad range of other commercial applications, including the detection of small numbers of molecules, such as the ultrasensitive detection of explosives and groundwater contaminants.


Assuntos
Escherichia coli O157/isolamento & purificação , Microbiologia de Alimentos , Microbiologia da Água , Animais , Bovinos , Estudos de Viabilidade , Citometria de Fluxo/instrumentação , Imunofluorescência , Lasers , Carne/microbiologia
3.
Appl Opt ; 16(2): 290-1, 1977 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-20168479
4.
Appl Opt ; 16(10): 2605-7, 1977 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20174188
5.
Science ; 194(4271): 1309-18, 1976 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-17797091

RESUMO

Forty-six days after Viking 1 landed, Viking 2 landed in Utopia Planitia, about 6500 kilometers away from the landing site of Viking 1. Images show that in the immediate vicinity of the Viking 2 landing site the surface is covered with rocks, some of which are partially buried, and fine-grained materials. The surface sampler, the lander cameras, engineering sensors, and some data from the other lander experiments were used to investigate the properties of the surface. Lander 2 has a more homogeneous surface, more coarse-grained material, an extensive crust, small rocks or clods which seem to be difficult to collect, and more extensive erosion by the retro-engine exhaust gases than lander 1. A report on the physical properties of the martian surface based on data obtained through sol 58 on Viking 2 and a brief description of activities on Viking 1 after sol 36 are given.

6.
Science ; 194(4260): 91-7, 1976 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-17793088

RESUMO

The location of the Viking 1 lander is most ideal for the study of soil properties because it has one footpad in soft material and one on hard material. As each soil sample was acquired, information on soil properties was obtained. Although analysis is still under way, early results on bulk density, particle size, angle of internal friction, cohesion, adhesion, and penetration resistance of the soil of Mars are presented.

7.
Science ; 193(4255): 805-9, 1976 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-17747786

RESUMO

The purpose of the physical properties experiment is to determine the characteristics of the martian "soil" based on the use of the Viking lander imaging system, the surface sampler, and engineering sensors. Viking 1 lander made physical contact with the surface of Mars at 11:53:07.1 hours on 20 July 1976 G.M.T. Twenty-five seconds later a high-resolution image sequence of the area around a footpad was started which contained the first information about surface conditions on Mars. The next image is a survey of the martian landscape in front of the lander, including a view of the top support of two of the landing legs. Each leg has a stroke gauge which extends from the top of the leg support an amount equal to the crushing experienced by the shock absorbers during touchdown. Subsequent images provided views of all three stroke gauges which, together with the knowledge of the impact velocity, allow determination of "soil" properties. In the images there is evidence of surface erosion from the engines. Several laboratory tests were carried out prior to the mission with a descent engine to determine what surface alterations might occur during a Mars landing. On sol 2 the shroud, which protected the surface sampler collector head from biological contamination, was ejected onto the surface. Later a cylindrical pin which dropped from the boom housing of the surface sampler during the modified unlatching sequence produced a crater (the second Mars penetrometer experiment). These two experiments provided further insight into the physical properties of the martian surface.

8.
Appl Opt ; 15(5): 1099-100, 1976 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-20165128
9.
Science ; 173(3999): 808-12, 1971 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-17812190

RESUMO

Recently completed high-resolution radar maps of the moon contain information on the decimeter-scale structure of the surface. When this information is combined with eclipse thermal-enhancement data and with high-resolution Lunar Orbiter photography, the surface morphology is revealed in some detail. A geological history for certain features and subareas can be developed, which provides one possible framework for the interpretation of the findings from the Apollo 15 landing. Frequency of decimeter-and meter-size blocks in and around lunar craters, given by the remote-sensed data, supports a multilayer structure in the Palus Putredinis mare region, as well as a great age for the bordering Apennine Mountains scarp.

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