Abstract-Teachers' beliefs are important for understanding and improving educational process. They closely guide language teachers to adopt their teaching strategies for coping with their daily language teaching challenges, influence their general well-being, and in turn, shape language learners' learning environment, their motivation and their language achievement and ability. This essay studies some previous researches on teachers' beliefs, and analyzes the role of three teachers' beliefs in the language teaching-learning process. The first part clarifies the concept of teachers' beliefs, the second part illustrates three essential teachers' beliefs about learners, learning and teachers themselves, and their role in the language teaching-learning process, the third part is the conclusion, which is consistent with the concept of teachers' beliefs.

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Melatonin receptors (MT1 and MT2 in humans) are family A G protein–coupled receptors that respond to the neurohormone melatonin to regulate circadian rhythm and sleep. Numerous efforts have been made to develop drugs targeting melatonin receptors for the treatment of insomnia, circadian rhythm disorder, and cancer. However, designing subtype-selective melatonergic drugs remains challenging. Here, we report the cryo-EM structures of the MT1–Gi signaling complex with 2-iodomelatonin and ramelteon and the MT2–Gi signaling complex with ramelteon. These structures, together with the reported functional data, reveal that although MT1 and MT2 possess highly similar orthosteric ligand-binding pockets, they also display distinctive features that could be targeted to design subtype-selective drugs. The unique structural motifs in MT1 and MT2 mediate structural rearrangements with a particularly wide opening on the cytoplasmic side. Gi is engaged in the receptor core shared by MT1 and MT2 and presents a conformation deviating from those in other Gi complexes. Together, our results provide new clues for designing melatonergic drugs and further insights into understanding the G protein coupling mechanism.

In this work, the development of a tryptophan sensor and its application to milk are described. The mixed metal (copper and cobalt) hexacynoferrates are electrodeposited on the graphite electrode, and this film exhibits an electrocatalytic activity towards for the oxidation of tryptophan. The experimental conditions, including the scan cycles, the ratio of copper(II) and cobalt(II), pH value, applied potential, are investigated in detail. At the optimal conditions, the eletctrocatalytic response is a linear relationship with the concentration of tryptophan in the range of 10 μM and 900 μM, with a detection limit of about 6 μM. This modified electrode was also successfully used to detect the tryptophan concentration in milk.