Detection threshold increasing

An ingenious whole-cell mechanism-based assay using an antisense fabF RNA was developed to increase the detection threshold to FabH/F inhibitors in S. aureus. A range of new natural products was thus... 

Neotropical bats Desmodus rotundus, Artibeus literatus, and Phyllostomus discolor) are very sensitive to butanoic acid their detection threshold lies between 1.5 x 10 ° and 1.5 x 10 mol/1 (Schmidt, 1975). The short-tailed fruit bat Carollia perspicillata) has detection thresholds for 18 odorants ranging from 3.6 x 10 to 2.7 X 10 ° molecules/cm air. The animals were most sensitive to fruit-typical compounds such as ethyl butyrate (5.4 x 10 °molecules/cm ), w-pentyl acetate (2.8 X 10 °molecules/cm ), andlinalool(1.8 x 10 molecules/cm ), suggesting nutritional specialization of chemoreception (Laska, 1990). The bats increased their respiration rate from a basal rate of 2-4 Hz to as much as 12 Hz when confronted with an odor of high concentration. 

On the other hand, the X-ray intensity in the hard X-ray band (16 - 28 keV) exhibits much less change than those in the soft X-ray band. The first positive detection was on July 4, 1987. It should be mentioned, however, that the epoch when the hard X-ray intensity exceeded the Ginga detection threshold remains somewhat uncertain. This is because the observing condition was unfavorable in May and June, 1987. Since the detection, the intensity in the hard X-ray band has remained almost constant within the statistical uncertainties through December, 1987. In the January flare, the hard X-ray intensity increased simultaneously by a factor of two, which was however much smaller than the factor of increase in the soft X-ray band. 

Pereira et al. (2010c,d) found that the levels of 5-hydroxymethyl-2-furfural and 2-furfural in sweet wines (Malvasia, Boal) increased slight for sweet (Malvasia) when estufagem was conducted at 30 °C. In dry wines (Sercial), their content was found below to its detection threshold. At higher temperatures (45 and 55 °C) a continuous increase was observed. Thus, the presence of 5-hydroxymethyl-2-furfural can be easily controlled during baking process by adjusting the temperature. 

Concerning the impact of ethanol on aroma perception, Pet ka et al. (2003) showed that ethanol at low concentrations (under 10%) could decrease aroma compound detection threshold. Nevertheless, Grosch (2001) observed that the less ethanol present in a complex wine model mixture, the greater the intensity of the fruity and floral odours. Although this effect could be easily explained by the increased partial pressure of the odorants with reduced ethanol concentration, they showed in GC-0 (gas chromatography-olfactometry) experiments that ethanol strongly increased the odour threshold of wine volatiles. In fact the reduction in odour activity of the wine volatiles when ethanol was added was much larger than the reduction in their partial pressure. 

Canola Oil Canola oil is obtained from low erucic acid, low glucosinolate rapeseed. The unique polyunsaturated fatty acid and low saturated composition of canola oil differentiates it from other oils. It has a higher oleic acid (18 1) content (55%) and lower linoleic acid (18 2) content (26%) than most other vegetable oils, but it contains 8-12% of linolenic acid (18 3) (58). Canola oil is most widely used in Canada and is considered a nutritionally balanced oil because of its favorable ratio of near 2 1 for linoleic to linolenic acid content. Unlike most other edible oils, the major breakdown products of canola oil are the cis, trans- and tram, trans-2,4-heptadienals with an odor character generally described as oily, fatty, and putty. Stored canola oil shows a sharp increase in the content of its degradation products, which are well above their odor detection thresholds. The aroma is dominated by cis, tram-, tram, frani-2,4-heptadienals, hexanal, nonanal, and the cis, trans- and... 

The increase in density in HUs or CT numbers is linearly dependent on the iodine concentration (mgl/mL) of the injected contrast medium. CT has two advantages over projection radiography. One is the significant increase in contrast resolution and sensitivity, which reduces the contrast detection threshold, thereby allowing a lower level of concentration of contrast media to be administered the other is the cross-sectional imaging, which permits successive visualization of structures without the superposition of other tissues to affect the image quality (632). 

Our published data also show that behavioral deficits in NL3 R451C mice are associated with an increase in inhibitory synaptic markers, increased evoked excitatory synaptic transmission, increased numbers of inhibitory synaptic puncta above detection threshold, but no change in the number of symmetric or asymmetric synapses by electron microscopy (Tabuchi et al., 2007) (not reproduced here). This increase in inhibitory synaptic function is consistent with the hypothesis that autism-like behaviors may be due to alterations in excitatory to inhibitory balance. 

The increase in perceived intensity with concentration can be represented by a straight line, as shown in Figure 8.2, for odorants A and B. The slope indicates how fast odour intensity rises with concentration and the intercept defines the detection threshold. There are two important characteristics of this type of data ... 

The threshold at 248-nm irradiation is not clearly defined as compared to the 308-nm threshold. A description as a threshold fluence region [177] is more appropriate. In the fluence range from 16 to 32 mj cm 2 an increase of AA/F is detected. The increase is exponential, followed by a constant area as shown in Fig. 25. This was also seen by Kiiper et al. [63] and ascribed to a photothermal mechanism . The threshold behavior indicates that a photochemical model can be applied, at least for an irradiation at 308 nm. 

A brief summary of electronic nose instruments currently available is now presented, followed by a discussion of strategies that may be or are being used to reduce the detection threshold of sensor-based electronic noses and hence increase their suitability to the ultimate detection of explosive materials. Readers interested in further details on electronic noses are directed towards a comprehensive book published in 2003 [5] that... 

Determination of the recognition thresholds of aqueous solutions of the umami tasting monosodium glutamate (MSG) and the salty tasting sodium chloride (NaCl), respectively, in the absence or presence of equimolar amounts of the alapyridaine enantiomers revealed that the detection thresholds of MSG (1.5 mmol/L) and NaCl (10 mmol/L) were 8 and 5 times lower when (+)-(5 )-alapyridaine was present 13). On the basis of these data it might be concluded that alapyridaine is a multivalent taste enhancer increasing the human sensitivity for sweetness, saltiness, and umami taste. 

Davis, R. G., 1978, Increased bitter taste detection thresholds in Yucatan inhabitants related to coffee as a dietary source of niacin, Chem. Senses Flav., 3 423. 

Urinary Total Protein and Albumin Urinary total protein and albumin have been nsed for decades as glomerular injury biomarkers and, more recently, were qualified as measurements of glomerular filtration and tubular reabsorption function (Ferguson et al., 2008 Bonventre et al., 2010). Compared with blood concentrations of protein/albumin, a small amount of protein and albumin (microalbumin, which is below the albumin detection threshold by the conventional urinary dipstick 30-300 mg/L) enters the filtrate by the glomerulus and is reabsorbed and subsequently catabolized in the normal kidney proximal tubnle (Vaidya et al., 2008 Charlton et al., 2014). Therefore, increased urinary protein/albumin can reflect glomerular injury, tubular injury, or combined effects, though albuminuria can be observed in rats secondary to other effects such as dehydration or hypertensive conditions (Haschek et al., 2013). 

There are several definitions of threshold. The detection threshold is defined as the lowest stimulus eliciting a sensorial response, even though no identification can be reached. The recognition threshold or identification threshold is the level of stimulus at which the specific stimulus can be identified. The differential threshold or just noticeable difference, is the minimum increase in a stimulus required to detect a difference in the perception. 

---