Theoretical study of a p-n homojunction SiGe field-effect transistor covalent functionalization.

p-n homojunctions are superior to p-n heterojunctions in constructing nanoscale functional devices, owing to the excellent crystallographic alignment. We tune the electronic properties of monolayer siligene (SiGe) into p/n-type the covalent functionalization of electrophilic/nucleophilic dopants, using quantum transport calculations. It is found that the n-type doping effect of K atoms is stronger than that of benzyl viologen (BV) molecule on the surface of SiGe monolayer, owing to the strong covalent interaction.

Identification of hyperpolarization-activated calcium channels in apical pollen tubes of Pyrus pyrifolia.

The pollen tube has been widely used to study the mechanisms underlying polarized tip growth in plants. A steep tip-to-base gradient of free cytosolic calcium ([Ca(2+)](cyt)) is essential for pollen-tube growth. Local Ca(2+) influx mediated by Ca(2+)-permeable channels plays a key role in maintaining this [Ca(2+)](cyt) gradient.