Background: Protocatechuic acid (PCA) is a natural phenolic acid widely distributed in plants and is considered as an active component of some traditional Chinese herbal medicines such as Cibotium barometz (L.) J.Sm, Stenoloma chusanum (L.) Ching, Ilex chinensis Sims. PCA was reported to possess various pharmacological effects which may be closely correlated with its antioxidant activities. However, the antioxidant of PCA has not been investigated systematically yet. Methods: In the study, the antioxidant activities of protocatechuic acid were measured in vitro using various antioxidant assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH•), 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS+•), superoxide anion radicals (•O2-) and hydroxyl radical (•OH) scavenging activity, ferric ions (Fe3+) and cupric ions (Cu2+) reducing power, ferrous ions (Fe2+) and cupric ions (Cu2+) chelating activity, compared with the positive controls Trolox or BHT.Results: In all assays, PCA along with positive controls exhibited dose-dependently antioxidant ability. Comparing to a standard antioxidant Trolox, the relative antioxidant activity of PCA (i.e. the ratio of IC50(Trolox)/IC50(PCA) ) was calculated as 2.8, 2.3, 3.7, 6.1, 4.2, 1.0, 2.7, 1.5, respectively, for DPPH, ABTS, reducing power (Fe3+), reducing power (Cu2+), superoxide anion radical-scavenging, hydroxyl radical-scavenging, chelating ability (Fe2+) and chelating ability (Cu2+). Conclusion: Comparing to Trolox, PCA shows much more effective antioxidant activity in vitro in both lipid and aqueous media. Hence, it could therefore be used in pharmacological or food industry as a natural antioxidant. It may exhibit antioxidant activity by both chelating metal transition ions as well as by scavenging free radicals via donating hydrogen atom (H•) or electron (e).Keywords: Protocatechuic acid, antioxidant, reducing power, free radical-scavenging, chelating ability.

To achieve the in-depth combination of informatization and intelligence has become a development trend in the nuclear power industry, and the digitization/intelligence of instrumentation is a big part. Based on the technical status of nuclear power instruments and industrial integrated circuits, this paper analyzes the feasibility and suggestions of intelligent/digital instrument application for nuclear power plant by combing the environmental conditions of nuclear power, intelligence/digitization of typical meters, testing and verification etc. basic work.

Reliability issues of TFT integrated gate driver are still of great concern for large size (i.e. TV) display applications, especially for a‐Si:H TFT integrated panels with stressing test of high temperature and high humidity (HTHHO). In this paper, current detection method is proposed for gate driver failure identification. Measurements of 55‐inch UHD TV (4K) panel with integrated gate driver are carried out. It is found that gate driver failure after HTHHO are strongly associates with via‐hole open of clock bus‐lines. It is demonstrated that current through clock lines will be increased with prolonged falling edge due to multi‐pulses of gate driver outputs. And clock bus‐line open is caused by oxygen of Cu after long operating time during the stressing test.