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...

Baryon production is studied within the framework of quantized fragmentation a QCD string. Baryons appear in model fairly intuitive way, with help causally connected string breakups. A simple helical approximation flux tube parameters constrained by mass spectrum light mesons sufficient to reproduce masses baryons.

Turbulent wake flows behind helical- and straight-bladed vertical axis wind turbines (VAWTs) in boundary layer turbulence are numerically studied using the large-eddy simulation (LES) method combined with actuator line model. Based on LES data, systematic statistical analyses performed to explore effects of blade geometry characteristics turbine wake. The time-averaged velocity fields show that...

Foundation module, the complex helical cuts are produced in a more efficient manner. Also, since Pro/E can easily construct variable pitch helixes (see Figure 1) the process of creating the helical paths was greatly simplified. The paths produced in this manner were parametric, meaning they could easily be changed without the need to reconstruct them as the design evolved. A 30% Snake supercond...

fouling is one of the main parameters in design of any exchanger. ignoring this parameter causes problems such as overheating or under- heating of process streams. in this article a heat exchanger network was designed using process streams data in cdu of tehran refinery. then using tema fouling factors, network exchangers were designed and area and cost were estimated. by changing fouling facto...

We introduce a new strategy for fabricating a seamless three-dimensional (3D) helical microreactor utilizing a silicone tube and a paraffin mold. With this method, various shapes and sizes of 3D helical microreactors were fabricated, and a complicated and laborious photolithographic process, or 3D printing, was eliminated. With dramatically enhanced portability at a significantly reduced fabric...

OBJECTIVE Our objective was to determine whether adjustments related to patient age are made in the scanning parameters that are determinants of radiation dose for helical CT of pediatric patients. SUBJECTS AND METHODS This prospective investigation included all body (chest and abdomen) helical CT examinations (n = 58) of neonates, infants, and children (n = 32) referred from outside institut...