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991.
Lemieux Anthony F.; Fisher Jeffrey D.; Pratto Felicia 《Canadian Metallurgical Quarterly》2008,27(3):349
Objective: This research examines the process of conducting and evaluating a music-based HIV prevention intervention among urban adolescents, and is informed by the information, motivation, behavioral skills (IMB) model. Design: Musically talented opinion leaders were recruited to write, record, and distribute HIV prevention themed music to their peers to increase HIV prevention motivation, behavioral skills, and behaviors. In this 3-month field experiment, participants were 306 students enrolled in health classes at each of three large multiracial urban high schools (one treatment school; two control schools). Main Outcome Measures: Measures of HIV prevention information, motivation, behavioral skills, and behaviors, both pre- and postintervention. Results and Conclusion: Results indicate that the intervention influenced several aspects of HIV prevention motivation, behavioral skills, and condom use and HIV testing behaviors. This research demonstrates that the incorporation of music into HIV prevention interventions for adolescents has the potential to be effective. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
992.
993.
Donohue MJ Best JM Smallwood AW Kostich M Rodgers M Shoemaker JA 《Analytical chemistry》2007,79(5):1939-1946
The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the whole cells of both reference strains and unknown Aeromonas isolates obtained from water distribution systems. A library of over 45 unique m/z signatures was created from 40 strains that are representative of the 17 recognized species of Aeromonas, as well as 3 reference strains from genus Vibrio and 2 reference strains from Plesiomonas shigelloides. The library was used to help speciate 52 isolates of Aeromonas. The environmental isolates were broken up into 2 blind studies. Group 1 contained isolates that had a recognizable phenotypic profile and group 2 contained isolates that had an atypical phenotypic profile. MALDI-MS analysis of the water isolates in group 1 matched the phenotypic identification in all cases. In group 2, the MALDI-MS-based determination confirmed the identity of 18 of the 27 isolates. These results demonstrate that MALDI-MS analysis can rapidly and accurately classify species of the genus Aeromonas, making it a powerful tool especially suited for environmental monitoring and detection of microbial hazards in drinking water. 相似文献
994.
Double-codified gold nanolabels for enhanced immunoanalysis 总被引:7,自引:0,他引:7
Ambrosi A Castañeda MT Killard AJ Smyth MR Alegret S Merkoçi A 《Analytical chemistry》2007,79(14):5232-5240
A novel double-codified nanolabel (DC-AuNP) based on gold nanoparticle (AuNP) modified with anti-human IgG peroxidase (HRP)-conjugated antibody is reported. It represents a simple assay that allows enhanced spectrophotometric and electrochemical detection of antigen human IgG as a model protein. The method takes advantage of two properties of the DC-AuNP label: first, the HRP label activity toward the OPD chromogen that can be related to the analyte concentration and measured spectrophotometrically; second, the intrinsic electrochemical properties of the gold nanoparticle labels that being proportional to the protein concentration can be directly quantified by stripping voltammetry. Beside these two main direct determinations of human IgG, a secondary indirect detection was also applicable to this system, exploiting the high molar absorptivity of gold colloids, by which, the color intensity of their solution was proportional to the concentration of the antigen used in the assay. Paramagnetic beads were used as supporting material to immobilize the sandwich-type immunocomplexes resulting in incubation and washing times shorter than those typically needed in classical ELISA tests by means of a rapid magnetic separation of the unbound components. A built-in magnet graphite-epoxy-composite electrode allowed a sensibly enhanced adsorption and electrochemical quantification of the specifically captured AuNPs. The used DC-AuNP label showed an excellent specificity/selectivity, as a matter of fact using a different antigen (goat IgG) a minimal nonspecific electrochemical or spectrophotometric signal was measured. The detection limits for this novel double-codified nanoparticle-based assay were 52 and 260 pg of human IgG/mL for the spectrophotometric (HRP-based) and electrochemical (AuNP-based) detections, respectively, much lower than those typically achieved by ELISA tests. The developed label and method is versatile, offers enhanced performances, and can be easily extended to other protein detection schemes as well as in DNA analysis. 相似文献
995.
Buck AH Campbell CJ Dickinson P Mountford CP Stoquert HC Terry JG Evans SA Keane LM Su TJ Mount AR Walton AJ Beattie JS Crain J Ghazal P 《Analytical chemistry》2007,79(12):4724-4728
We present a new type of DNA switch, based on the Holliday junction, that uses a combination of binding and conformational switching to enable specific label-free detection of DNA and RNA. We show that a single RNA oligonucleotide species can be detected in a complex mixture of extracted cellular RNA and demonstrate that by exploiting different aspects of the switch characteristics we can achieve 30-fold discrimination between single-nucleotide mismatches in a DNA oligonucleotide. 相似文献
996.
A cloud monitor instrument, sensing 8-14 microm infrared radiation, has been installed near McMurdo, Antarctica, in order to provide supporting cloud cover information for a high-resolution sky-viewing Fabry-Perot spectrometer experiment. Validation of the cloud monitor observations was performed by a 1 year long comparison with the available 6 h visual cloud observations, expressed in octas (obscured eighths of the sky). The agreement between visual observations and those of the cloud monitor is good--the variation being slightly over one step, or octa--except at the clear sky extreme, which the subjective visual observations tend to overestimate during dark and moonless conditions. Both visual observations and the cloud monitor measurements show an austral winter-summer difference with the winter being clearer. 相似文献
997.
Antje?BergmannEmail author J?rg?Te?mar Anthony?Owen 《Journal of Materials Science》2007,42(11):3732-3738
Biosynthetic poly[(R)-3-hydroxybutyrate] (PHB) undergoes a deleterious ageing process which has been attributed to progressive crystallisation.
In this work an attempt has been made to arrest this crystallisation behaviour by an irradiation treatment which is known
to induce cross-linking in many polymers. PHB films were irradiated with different doses of electrons and at different times
after the initiation of crystallisation. The degree of crystallinity was subsequently determined as a function of time after
irradiation using wide-angle X-ray scattering measurements. In addition, melting endotherms were obtained by differential
scanning calorimetry (DSC) and molecular weights by gel permeation chromatography (GPC). Corresponding tensile stress–strain
experiments were performed in order to obtain information on the mechanical properties of the sample films. The melting point
and molecular weights were found to decrease linearly with radiation dose indicating that higher radiation doses cause degradation
due to chain scission. However, lower doses applied to samples still in their amorphous state indicate a high degree of cross-linking,
in which a network is formed and the ageing process can be prevented to some extent. The tensile modulus and breaking strain
were influenced strongly by the point in time at which the material was irradiated during crystallisation. 相似文献
998.
Sandrine Marinhas Anthony Delahaye Laurence Fournaison 《International Journal of Refrigeration》2007,30(5):758-766
In the present paper, the suitability of hydrate slurries in secondary refrigeration was investigated by the means of a new hydrate solid-fraction model. Considering the high melting enthalpy of CO2-containing hydrates, slurries presenting high hydrate solid fractions can carry sufficient latent heat to be useful for a two-phase secondary-refrigerant application. The model presented in this paper allowed to calculate the solid fraction of CO2 and CO2–THF hydrate from thermodynamic conditions of pressure and temperature. Contrary to a previous work on single CO2 hydrates in a closed system, the present model can take into account hydrate mixture and is well adapted to additional CO2 injections (opened system). By relying on the hydrate-conversion model results, the study of hydrates in suspension in a carrying liquid was also studied in an experimental loop and was based on a formation process by CO2 injection in a cooled aqueous solution. 相似文献
999.
Kelly DJ Crawford A Dickinson SC Sims TJ Mundy J Hollander AP Prendergast PJ Hatton PV 《Journal of materials science. Materials in medicine》2007,18(2):273-281
The aim of this study was to determine whether or not biochemical markers can be used as surrogate measures for the mechanical
quality of tissue engineered cartilage. The biochemical composition of tissue engineered cartilage constructs were altered
by varying either (i) the initial cell seeding density of the scaffold (seeding density protocol) or (ii) the length of time
the engineered tissue was cultured (culture period protocol). The aggregate or Young’s moduli of the constructs were measured
(by confined or unconfined compression respectively), and compared with the composition of the extracellular matrix by quantitative
measurement of the glycosaminoglycan (GAG), hydroxyproline, collagen I and collagen II and collagen cross-links. The aggregate
modulus correlated positively with both GAG and collagen II content, but not with collagen I content. Young’s modulus correlated
positively with GAG, collagen II and collagen I content, and the ratio of mature to immature cross-links. There was no significant
correlation of Young’s Modulus with total collagen measured as hydroxyproline content. These results suggested that hydroxyproline
determination may be an unreliable indicator of mechanical quality of tissue engineered cartilage, and that a measure of collagen
II and GAG content is required to predict the biomechanical quality of tissue engineered cartilage. 相似文献
1000.
Bai J Liu K Ying K Jiang Y Zhang P Lau J 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(11):2300-2308
Quantitative ultrasound tissue characterization based on integrated backscatter (IB) has shown great potential in detecting myocardial ischemia. The magnitude of the cyclic variation in IB (CVIB) has recently been considered as one of the most promising parameters in assessing regional myocardial contractile performance. Our laboratory previously developed a novel ultrasonic fusion imaging method based on the CVIB. However, the major problem for clinical applications of this technique and other existing analytical methods based on IB is that the myocardial tissue can't be traced effectively without the cardiologist's intervention. In order to solve this problem, this paper presents a snake-based tracking algorithm to trace myocardial tissue automatically. A mathematical method is also introduced to extend the application of the snake model for detecting non-closed contours. The system developed in our previous research was redesigned to synchronize the radio frequency signal, the electrocardiographic signal, and the video signal, which allows verification of the system. Our results suggest that the system using the auto-tracking method increases the accuracy of detecting myocardial ischemia. 相似文献