A Flexible Humidity Sensor Based on Co3O4 Nanoneedles with High Sensitivity and Quick Response

A flexible humidity sensor has been realized based on Co3O4 nanoneedles via a deposition technique. High humidity sensing and excellent flexible properties are observed in the tests. The impedance of the as-prepared sensor decreases by nearly three orders of magnitude with increasing relative humidity (RH) from 11% to 95% on a semilogarithmic scale. The response and recovery times are about 3 and 6 s respectively. The maximum hysteresis is less than 4% under 80% RH. No obvious changes for the sensing performance can be obtained after 100 bending/extending cycles and bending tests. These performances make the current sensor a good candidate for flexible humidity detection.

A Quantitative Normal Fibrin Plate Assay

Astrup and co-workers introduced the normal fibrin plate assay method for assaying plasminogen activators in 1952. Over the years, this technique has been used as a semiplasminogen activators such as urokinase. Our laboratory designed experiments to investigate and establish parameters for the fibrin plate assay which would give a maximum and reproducible response to quantities of urokinase. The parameters investigated included molarity (ionic strength) and pH of the buffers used for both the fibrin clot and the unknown sample. To establish these conditions, a series of experiments were performed involving parallel line assays. With this procedure, the response to each parameter studied was compared at several different levels of activity. Statistical comparisons were made to determine how changes in the measured parameters would influence the sensitivity and precision of the assay. The outcome of these studies led to the development of a routine normal fibrin plate assay for urokinase using a sample pad and a standard curve with an activity range of 0.1 to 0.8 IU. These conditions yielded a linear response on a semilogarithmic scale. When assaying urokinase, the results of the conventional fibrin plate assay (one level unknown vs. four levels standard) and the dose response-parallel line-fibrin plate assay (four levels unknown vs. four levels standard) are equivalent. The coefficient of variation for both assays was 2 to 5 percent.

Der Zusammenhang zwischen dem Molekulargewicht pflanzlicher Viren und der spektrophotometrisch bestimmbaren Größe bv

The correlation between molecular weight (MW) of plant viruses and the spectrophotometric value bv (see the preceeding paper) has been established. The dependence of bv on the MW is represented by a straight line on a semilogarithmic scale. By means of this line it is possible to evaluate the MW of a plant virus by measuring bv if the virus entity is a pure ribonucleoproteine containing RNA of a MW of 2 · 106. The resulting value for the MW of the virus is not affected by aggregation or breakdown of the virus, but is disturbed by proteine or nucleoproteine impurities. Therefore, it can be concluded that a preparation of a given virus contains non-virus components if the correlation of figure 1 is not fulfilled satisfactorily.