[Short-term memory characteristics of vibro-tactile perception in human fingertips].

This paper discusses the short-term memory of vibro-tactile perception of human fingertips. By using a self-developed vibro-tactile expression device, a recall experiment was firstly carried out among 20 subjects aged 20-30 (10 males and 10 females) to discover the memory span about the vibro-tactile perception of human fingertips. Within this memory span, a cognitive experiment analyzing the recognition accuracy and the reaction time was carried out. The results showed: (1) The vibro-tactile memory span of human fingertip is 4 ± 1; (2) The vibro-tactile memory span increases as the discrete intensity between vibration stimuli increases; (3) Too long or too short vibration duration will reduce the vibro-tactile memory span, and the optimal vibration duration for men is 400 ms, for women is 300 ms; (4) The more the number of vibration stimuli is perceived by the human fingertip, the lower the recognition accuracy and the longer the reaction time it needs; (5) Compared with the vibration stimuli in disorder, people are more likely to remember the vibration stimuli in increasing/decreasing order; (6) The information extraction mechanism of the short-term memory about fingertip vibro-tactile perception bases a point to point scanning process among these stimuli. These results help to understand the human fingertip tactile characteristics and provide a physiological basis for the study of tactile feedback technologies.

A review of pretreatment and analytical methods of biogenic amines in food and biological samples since 2010.

Biogenic amines (BAs), mainly produced by amino acid decarboxylation, are widespread in foods and human organisms. Appropriate intake of BAs is beneficial to the human body, while excessive consumption may cause discomfort. Meanwhile, BAs are a kind of chemical marker for evaluating meat freshness. For these reasons, simple, rapid and efficient methods have been developed for the determination of BAs in food and biological products. This review introduces the provenance, classification and physiological activity of eight essential BAs and summarizes the dominant pretreatment and analysis methods since 2010. Pretreatment technologies mainly include the "dilute and shoot" method, ultrasonic assisted extraction, solid-phase extraction, matrix solid-phase dispersion, dispersive liquid-liquid microextraction, etc. Determination methods include liquid chromatography coupled to ultraviolet or fluorescence detectors, liquid chromatography tandem mass spectrometry, capillary electrophoresis, biosensors and so on.

A general and efficient FeCl3-catalyzed nucleophilic substitution of propargylic alcohols.

A general and efficient FeCl3-catalyzed substitution reaction of propargylic alcohols with carbon- and heteroatom-centered nucleophiles such as allyl trimethylsilane, alcohols, aromatic compounds, thiols, and amides, leading to the construction of C-C, C-O, C-S and C-N bonds, has been developed.

BiCl3-catalyzed propargylic substitution reaction of propargylic alcohols with C-, O-, S- and N-centered nucleophiles.

A general and efficient BiCl3-catalyzed substitution reaction of propargylic alcohols with carbon and heteroatom-centered nucleophiles such as allyl trimethylsilane, alcohols, aromatic compounds, thiols and amides, leading to the construction of C-C, C-O, C-S and C-N bonds, has been developed.