Antiparallel helical bundles are found in a wide range of proteins. Often, four-helical bundles form tube-like structures, with binding sites for substrates or cofactors near their centers. For example, a transmembrane four-helical bundle in cytochrome bc(1) binds a pair of porphyrins in an elongated central cavity running down the center of the structure. Antiparallel helical barrels with larg...

BACKGROUND AND PURPOSE MDCT has some specific scan parameters that may systematically increase or decrease radiation dose to patients. This study explored the scan protocol parameters that impact radiation dose in temporal bone MDCT and determined the optimal scan parameters that balance radiation dose with diagnostic image quality. MATERIALS AND METHODS Using exsomatized cadaveric heads, tra...

The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO(2) fibres via transcription of the ...

The hydrothermal behavior in a helical double-tube heat exchanger is numerically estimated. A new type of swirl generator with two sections, including; outer curved blades and semi-conical section holes the inner section, employed. Two geometrical factors, containing length (L1) position (S), are used for investigation. calculations were performed by commercial FVM code, ANSYS FLUENT 18.2. nume...