Gradual Increase In Sensitivity Research Articles

The role of substrate temperature on the performance of humidity sensors manufactured from cerium oxide thin films

Cerium oxide (CeO2) thin films as humidity sensors are obtained by pulsed laser deposition (PLD) grown on Si (100) substrate. CeO2 nanoparticles were taken as target materials for PLD technique. The effect of film deposition condition, such as deposition temperature on performance sensor, was explored. The substrate temperature ranges varied from 300 to 700 °C. The structural and surface morphologies were examined by X-ray diffractometer (XRD) and scanning electronic microscopy (SEM), respectively. The capacitance and resistance of the sensors were tested. The sensor utilizing CeO2 films exhibited high sensitivity, and the increase in humidity led to a gradual increase in sensitivity and decreased resistance. The sensor performance is highly dependent on morphology and surface, which in turn is affected by the change in electrical properties of the film.

Sensing performance of zirconia-based gas sensor using titania sensing-electrode added with palladium

The sensing characteristics of a yttria-stabilized zirconia (YSZ)-based sensor using a sensing electrode (SE) consisting of rod-shaped TiO2 added with 1 wt.% of nano-sized Pd particles (abbreviated as TiO2(+ Pd)-SE) were evaluated, aiming at selective detection of hydrocarbons. The rod-shaped TiO2-SE without Pd addition (TiO2-SE) was found to give high sensitivities to both C3H8 and C3H6 which were used as representatives of alkane and alkene groups, respectively, in hydrocarbons (HCs), while TiO2(+ Pd)-SE gave selective detection of C3H8. The evaluation of catalytic activity to the gas-phase oxidation of HCs for the SE materials revealed that the oxidation of C3H6 was largely promoted by the Pd addition, leading to the high selectivity to C3H8 for the sensor using TiO2(+ Pd)-SE. From the results of polarization-curve measurements, the current value for the cathodic reaction of O2 was found to be slightly decreased by the Pd addition, while those for the anodic reaction of C3H8 and C3H6 were largely decreased. This is presumably due to the decrease in the actual concentration of C3H8 and C3H6 at the SE/YSZ interface owing to the promoted gas-phase oxidation of these HCs through the TiO2(+ Pd)-SE layer. XRD measurements as well as SEM observations confirmed that the added Pd particles were existing as PdO particles on the surface of the rutile-type TiO2 rods after the SE fabrication process. The stability test revealed that the C3H8 sensitivity of the sensor using TiO2(+ Pd)-SE gradually increased and reached the stable value after the 12 day operation. By considering the results of the complex-impedance analysis, we believed that this gradual increase in sensitivity was due to the decrease in the catalytic activity against the gas-phase oxidation of C3H8 in the TiO2(+ Pd)-SE layer.

Terahertz detector with transmission-line type superconducting tunnel junctions

We demonstrate a new type of terahertz detector with superconducting tunnel junctions. The detector has two long junctions integrated on both wings of a log-periodic antenna. In this type of detector, the long junction is a lossy transmission line working based on the Cooper-pair breaking, as well as a standing-wave resonance line working based on the photon-assisted tunneling. A prototype detector using Nb/Al/AlOx/Al/Nb junctions was fabricated, and the principle of the detector was verified. The prototype shows a gradual increase in sensitivity starting from 0.35 THz. We have also identified a resonance signal at 0.25 THz below the effective gap frequency.

Dormancy release during hydrated storage in Lolium rigidum seeds is dependent on temperature, light quality, and hydration status.

The influence of temperature, light environment, and seed hydration on the rate of dormancy release in Lolium rigidum (annual ryegrass) seeds during hydrated storage (stratification) was investigated. In a series of experiments, seeds were subjected to a range of temperatures (nine between 5 degrees C and 37 degrees C), light (white, red, far-red, and dark), and hydration (4-70 g H(2)O 100 g(-1) FW) during stratification for up to 80 d. Samples were germinated periodically at 25/15 degrees C or constant 15, 20, or 25 degrees C with a 12 h photoperiod to determine dormancy status. Dark-stratification was an alternative, but not equivalent dormancy release mechanism to dry after-ripening in annual ryegrass seeds. Dormancy release during dark-stratification caused a gradual increase in sensitivity to light, but germination in darkness remained negligible. Germination, but not dormancy release, was greater under fluctuating diurnal temperatures than the respective mean temperatures delivered constantly. Dormancy release rate was a positive linear function of dark-stratification temperature above a base temperature for dormancy release of 6.9 degrees C. Dormancy release at temperatures up to 30 degrees C could be described in terms of thermal dark-stratification time, but the rate of dormancy release was slower at < or =15 degrees C (244 degrees Cd/probit increase in germination) than > or =20 degrees C (208 degrees Cd/probit). Stratification in red or white, but not far-red light, inhibited dormancy release, as did insufficient (<40 g H(2)O 100 g(-1) FW) seed hydration. The influence of dark-stratification on dormancy status in annual ryegrass seeds is discussed in terms of a hypothetical increase in available membrane-bound phytochrome receptors.

Dormancy-related changes in cytokinin efficacy and metabolism in potato tubers during postharvest storage

The metabolism of [3H]-zeatin (Z) and[3H]-isopentenyladenosine (IPA) in potato tubers was examined inrelation to changes in cytokinin efficacy during postharvest storage anddormancy progression. Exogenous radiolabeled cytokinins were rapidlymetabolizedby dormant and nondormant tubers. Following injection, [3H]-Z wasmetabolized to zeatin riboside, adenine derivatives andzeatin-riboside-5′-monophosphate. Four hours after injection, less than60% of the recovered radioactivity was associated with unmetabolized[3H]-Z. [3H]-IPA was also rapidly metabolized to severalmetabolites including: IPA-5′-monophosphate, adenine derivatives andzeatin riboside. Four hours after injection, less than 50% of therecovered radioactivity was associated with [3H]-IPA. Cytokininsensitivity was assessed by determining the effects of exogenous Z or IPA ontuber sprouting. Immediately after harvest and during the initial period ofstorage, tubers were dormant and exogenous Z or IPA were completely ineffectivein breaking tuber dormancy. Thereafter, dormant tubers exhibited a gradualincrease in sensitivity to both cytokinins. Cytokinin sensitivity continued toincrease as postharvest storage was extended and dormancy weakened. The lengthof postharvest storage (hence dormancy status) had no apparent effects on themetabolism of either cytokinin. Neither the rate of metabolism nor the natureofmetabolites detected was affected by the length of postharvest storage. Theseresults suggest that changes in cytokinin efficacy in dormant potato tubersduring postharvest storage are not the result of differential catabolism butrather are due to other cellular processes such as hormone perception and/orsignal transduction.

ERG assessment of zebrafish retinal development.

Research has shown that adult zebrafish have a complex visual system, with two possible opponent mechanisms. Anatomically, zebrafish retina develops in a sequential manner and is immature at hatching. The purpose of the present study was to assess zebrafish retinal development using the electroretinogram (ERG). ERG responses to visual stimuli were obtained from 4-5, 6-8, 13-15, and 21-24 days postfertilization (dpf) zebrafish. Individual waveforms were assessed and compared across the four age groups. Spectral-sensitivity functions were calculated for the a- and b-wave components of the ERG response. Results showed that the ERG waveforms and spectral-sensitivity functions varied with age. While the 21-24 dpf subjects had an ERG waveform that was similar to that of adults, the younger subjects did not. Although there were modest differences in the a-wave spectral sensitivity, substantial differences were found in the b-wave spectral sensitivities across the ages. There was a consistent strong response to ultraviolet wavelengths, while across the remaining parts of the spectrum, there was a gradual increase in sensitivity with age. Also, the 21-24 dpf subjects appear to have adult-like U- and S-cone functions, but were missing the L-M and the M-S opponent mechanisms found in the adult. These results support the findings of the anatomical studies and demonstrate that the zebrafish is a useful model for examining the development of retinal function.

Effect of low serum concentrations (0%–2.5%) on growth, production, and shear sensitivity of hybridoma cells

In a stirred culture of hybridoma cells, the effects of serum reduction from 2.5% to 0% on growth and monoclonal antibody production have been investigated. The shear sensitivity of cells from the same culture has been tested in a bubble column. Serum reduction does not greatly affect viable-cell concentrations, but cell specific monoclonal-antibody production rate shows a decreasing trend. A gradual increase in sensitivity for sparging, which is nor the result of a long-term biological effect, has been measured in a bubble column at decreasing fetal calf serum concentrations. Finally, the hypothetical killing-volume model describing the death rate of insect cells in bubble columns has now been completely validated for the pertinent hybridoma-cell line.

Lokalanästhetische Wirkung und subjektive Verträglichkeit von Carteolol 2% und Metipranolol 0,6% bei Augengesunden

In a placebo-controlled, randomized, prospective, parallel, double-blind trial, corneal sensitivity was studied in 35 people with healthy eyes before and 1, 3, 6, 10, 15, and 30 minutes after application of carteolol 2% (20 eyes) and metipranolol 0.6% (20 eyes). Oxybuprocain 0.4% (local anesthetic, 10 eyes) served as a positive control substance, NaCl 0.9% (20 eyes) as a negative one (placebo). The test subjects assessed subjective tolerance of the test drugs on a four-step scale. Carteolol 2% did not decrease corneal sensitivity. There was no statistically significant difference between this group and the placebo group. Metipranolol 0.6% led to a decrease in corneal sensitivity of up to 14 mg (median), lasting up to 15 minutes. The decrease brought about by metipranolol 0.6% is about one-half of that caused by betaxolol 0.5%, but greater than that caused by timolol 0.5%. Oxybuprocain 0.4% causes corneal sensitivity to decrease below the measuring range of Cochet and Bonnet's esthesiometer (200 mg) for about 10 minutes. All but three eyes had returned to their initial corneal sensitivity values after 30 minutes. NaCl 0.9% eye drops do not decrease corneal sensitivity. On the contrary, a gradual increase in sensitivity (exercise effect) was found, which differed significantly from the initial value as of the 10th minute after drug application. These results confirm that it is necessary to check corneal sensitivity during topical beta-blocker therapy. "Responders," "sensitives," contact lens wearers, and patients with decreased corneal sensitivity (e.g., patients suffering from open-angle glaucoma with disk excavations, after cataract extraction or corneal transplantation) need frequent supervision.(ABSTRACT TRUNCATED AT 250 WORDS)

Intimacy of the neuroeffector junction and resistance to alpha-adrenoceptor-blockade of the neurogenic contractile response in vasa deferentia from guinea pig and rat.

The effect of phentolamine on the neurogenic contractile response in vasa deferentia from rat and guinea pig was studied during Wallerian degeneration. This response was also investigated after partial denervation (surgery or chemical sympathectomy by guanethidine treatment) in vasa deferentia from guinea pig. During Wallerian degeneration the response showed a gradual increase in sensitivity to phentolamine and was abolished in the late stages. The neurogenic contractile response of the partially denervated vas deferens was blocked by low concentrations of phentolamine. It is concluded that decreased intimacy of the neuroeffector junctions leads to increased susceptibility to alpha-adrenoceptor blockade of the contractile response to nerve stimulation. It is further concluded that the motor transmission in the vas deferens is essentially adrenergic. The resistance to alpha-adrenoceptor blockade of the initial phase of the contractile response to nerve stimulation of intact vasa deferentia from guinea pig and rat might well be explained by the "proximity theory" of Dale & Gaddum although participation of supplementary mediators cannot be excluded.

The Blue Road Geotraverse: Studies of short-period crustal dynamics, using continuously recording instruments

Abstract Short-period crustal dynamics concern the spectrum of processes between long-period seismic waves and those long-period processes which can be surveyed by repeated geodetic measurements. The instruments used are recording gravity meters, tiltmeters, and strain-meters. These instruments have conventionally been used for earth tidal research on a global scale. The gradual increase of sensitivity and resolution, however, has caused disturbances like oceanic tides, individual tidal movements of lithospheric blocks, stress accumulation, crustal loading by atmospheric pressure changes, precipitation, and tectonic processes to become a main problem. On the other hand, these “dirty effects” are an important source of information on the structure and dynamics of the lithosphere. In order to obtain this kind of information, a network of geodynamic stations is planned along the Blue Road Geotraverse, in addition to further interdisciplinary research.

Mechanism of action of sparteine sulfate on myometrial activity in vitro

The in vitro response of uterine muscle to sparteine sulfate was studied in 104 strips of human and 65 strips of rat uterine muscle. Sparteine sulfate influences the duration and frequency but not the maximum tension development of spontaneous activity in the rat myometrium. In all studies of electrically stimulated human and rat myometrium an increase of maximum tension was observed after sparteine sulfate stimulation. In the human no increase in sensitivity to sparteine sulfate was observed with advancing gestation. However, the gradual increase in sensitivity to Pitocin as pregnancy progresses has been observed by us as well as by several other investigators. The rat uterus, unlike the human uterus, exhibits an increased sensitivity to sparteine sulfate during advancing stages of pregnancy. A greater response is demonstrable during late pregnancy and is relatively refractile during early and midgestation. The response of muscle strips obtained from placental implantation sites to sparteine sulfate were less marked than uterine muscle strips from the opposite wall of the same uterus (nonplacental sites). Furthermore, the dose response range of human uterine muscle to increasing concentrations of sparteine sulfate was narrower than with Pitocin. Larger doses of sparteine sulfate produced myometrial contracture in normal Krebs' solution. Lower concentrations had a tendency to cause myometrial contracture on partially depolarized muscle. These studies suggest the major action of sparteine sulfate is directed at the cell membrane rather than directly on the contractile system of the uterine muscle cell.

A QUANTITATIVE STUDY OF PHENOCOPY PRODUCTION WITH MONOCHROMATIC ULTRAVIOLET IRRADIATION

1. Drosophila larvae, prepupae and pupae of various ages and genotypes were irradiated with ultraviolet of wave-length 2537 A and in dosages varying from 330 to 79,200 ergs/mm.2 The phenocopies produced varied with the age of the irradiated fly, the stock used, and the total dosages of the irradiation. Irradiation with ultraviolet does not cause a retardation of pupation as X-radiation does. 2. Larvae show a gradual increase in sensitivity to ultraviolet radiation with age from 50 to 100 hours after hatching from the egg to a maximum at one hour after pupation, then a sharp decrease in sensitivity with pupal age. There are two periods in the larval stage, one about 50 and one about 100 hours after hatching, of greater phenocopy production for a given amount of radiation. Irradiations during the first 24 hours of pupal life produce fewer phenocopies for a given amount of radiation than during the larval period. 3. The sensitive periods for the production of certain phenocopies by ultraviolet are compared with the sensitive periods for X-ray and temperature treatments. Some are identical, a few are different. 4. Irradiations of the same total dosage produce the same percentages of lethality and of phenocopies whether given at high or low intensities. The threshold level for the production of phenocopies varies with the age of the fly irradiated but is about 440 ergs/mm.2 A comparison is made of this threshold with the thresholds for the effect of ultraviolet on other biological systems and with the effect of X-rays on phenocopy production in Drosophila. 5. A hypothesis for the mechanism involved in the production of phenocopies by ultraviolet rays is discussed.