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Disiloxane groups, Si–O–Si, tend to have larger bond angles than their carbon counterparts, C–O–C. The Si–O–Si angle ranges from about 130–180°, whereas the C–O–C angle in ethers is typically 107–113°. Si–O–C groups are intermediate, tending to have bond angles smaller than Si–O–Si but larger than C–O–C.
For example, in the solid state at a temperature of 108 K, disiloxane itself has an Si−O−Si bond angle of 142°. [2] In contrast, the C−O−C bond angle in the carbon analogue of disiloxane, dimethyl ether, is 111°. [4] The unusual bond angle in disiloxane has been attributed primarily to negative hyperconjugation between oxygen p ...
The desired size of margin around the tumour can vary. In resections for breast cancer, there appears to be a difference between European and American radiation oncologists, with the former preferring larger margins of over 5 mm. [1]: section 2 Micrograph showing a positive cauterized surgical margin in an adenocarcinoma (center-top of image).
28 Si (the most abundant isotope, at 92.23%), 29 Si (4.67%), and 30 Si (3.1%) are stable. The longest-lived radioisotope is 32 Si, which is produced by cosmic ray spallation of argon . Its half-life has been determined to be approximately 150 years (with decay energy 0.21 MeV), and it decays by beta emission to 32 P (which has a 14.27-day half ...
Lesions lips, patient with hemorrhagic hereditary telangiectasia. Hereditary hemorrhagic telangiectasia (HHT), also known as Osler–Weber–Rendu disease and Osler–Weber–Rendu syndrome, is a rare autosomal dominant genetic disorder that leads to abnormal blood vessel formation in the skin, mucous membranes, and often in organs such as the lungs, liver, and brain.
Stereotactic surgery is a minimally invasive form of surgical intervention that makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radiosurgery (SRS), etc.
Bamboo sign; Banana sign; Bat wing appearance; Bear paw sign; Beveled edge sign; Bird of prey sign; Bite sign; Black pleura sign; Blade of grass sign (also known as Flame sign); Blumensaat's line
X-ray reflectivity (sometimes known as X-ray specular reflectivity, X-ray reflectometry, or XRR) is a surface-sensitive analytical technique used in chemistry, physics, and materials science to characterize surfaces, thin films and multilayers.