AIM To investigate the effect of a selective cyclooxigenase-2 (COX-2) inhibitor, rofecoxib, in the prevalence of experimental colon tumors in rats. EXPERIMENTAL DESIGN Experimental study with 35 male Sprague-Dawley rats, divided into four groups: a) control group without experimental manipulation (n = 5); b) pharmacological carcinogenesis with 1-2 dimethylhydrazine dihydrocloride (n = 10); c)...

A gas sensor based on quartz-enhanced photoacoustic detection and a fiber-coupled telecommunication distributed-feedback diode laser was designed and characterized for trace NH3 monitoring at a 1.53-microm wavelength (overtone absorption region). Signal and noise dependence on gas pressure were studied to optimize sensor performance. The ammonia concentration resulting in a noise-equivalent sig...

the present state-of-the-art in gas detection does not allow the precise titration of a combustible gas in air with a single catalytic sensor, because the signal depends also on other parameters than the oxidation of the gas. It is why the catalytic transducers always consist of both a detector and a compensating element. We present here a process which permits the avoidance of the compensating...

Template-free, rapid polymerisation was employed to synthesize polyaniline nanofibers using chemical oxidative polymerisation of aniline, with HCl as a dopant. The doped and dedoped nanofibers were deposited onto conductometric sapphire transducers for gas sensing applications. The sensors were exposed to various concentrations of hydrogen (H2) gas at room temperature. The sensitivity was measu...

zno and zno: mn nanocrystals were synthesized via reverse micelle method. the structural properties of nanocrystals were investigated by xrd. the xrd results indicated that the synthesized nanocrystals had a pure wurtzite (hexagonal phase) structure. resistive gas sensors were fabricated by providing ohmic contacts on the tablet obtained from compressed nanocrystals powder and the installation ...

in this study, a specific ch4 sensor is fabricated based on interdigitated electrode that modified with core-shell of tungsten carbide/tin oxide (wc/sno2) nanoparticles by wet chemical method in different percents of carbon and tungsten. the morphology of wet chemical-synthesized wc/sno2 core-shell was evaluated by different methods such as patterned x-ray diffraction (xrd), and particle size a...

The development of an interband cascade laser (ICL) based spectroscopic trace-gas sensor for the simultaneous detection of two atmospheric trace gases is reported. The sensor performance was evaluated using two ICLs capable of targeting formaldehyde (H2CO) and ethane (C2H6). Minimum detection limits of 3.5 ppbV for H2CO and 150 pptV for C2H6 was demonstrated with a 1 s integration time. The sen...