Boronate alpha effect

Due to electronegativity differences (B = 2.05, C = 2.55) and notwithstanding the electronic deficiency of boron, which is mitigated by the two electron-donating oxygen atoms (vide supra), the inductive effect of a boronate group should be that of a weak electron-donor. The NM R alpha effect of a boronate group is very small [27]. 

Vulpis (1973) added pure natural boron as H3B03, which contains about 19% B-10, to the blood culture. It was then irradiated with thermal neutrons from a reactor. The reaction of B-10(n,a)Li-7 within the culture served as alpha source. The dose range was 35 to 195 mGy according to her dose estimation which was complicated by subtracting the dose due to the reactor radiation alone. The dicentric chromosomes appeared to follow a linear response up to about 0.18 Gy and then leveled off to a plateau due to a "saturation effect. The relative biological efficiency (RBE) with respect to X-rays with the doses up to 5f1 Gy was found to be 23. v... 

Further improvement is effected by incorporating into the name six additional alpha bonds (from the two axial boron atoms to each of the three... 

Carboranes in Boron Neutron Capture Therapy of Cancer (B7YC2). The stable isotope of boron, B (19.8% natural abundance), is very effective as a neutron capture agent with the effective nuclear cross section of 3837 bams, while the "B nucleus is incapable of undergoing a BNC reaction. Therefore, the B-emiched carborane and borane-substituted biomolecules and dmgs are selectively dehvered to the cancer cells in the human body and then the tumor-localized B nucleii are bombarded with either thermal or epithermal neutrons that results in a fission reaction producing the high energy alpha (a) particles as shown in equation (2). 

In subsequent experiments, Biersack, et al. (29) used the boron (n,alpha) reaction to show the effect of pre- and post-irradiation damage on boron implantation profiles. By post-irradiating a boron implant in silicon with 200 keV H2, a migration of the boron to the Induced damage sites was observed. In the same paper, diffusion and trapping of lithium ions in niobium were reported. Using the lithium (n,alpha) reaction, they mapped irradiation Induced crystal defects through a depth of several micrometers with respect to several sample treatment conditions. 

Boron neutron capture therapy (BNCT) offers a potential method for localized destruction of tumor cells. The technology is based on the nuclear reaction between thermal neutrons and boron-10 (lOB) to yield alpha particles and lithium-7 nuclei. The destructive effect of this reaction is limited to a range of about the diameter of a single cell. In order for BNCT to be effective in cancer therapy, there must be selective delivery of an adequate concentration of lOB to tumors. Various types of antibodies as well as epidermal growth factor have been utilized to investigate receptor-mediated boron delivery however, in vivo studies have demonstrated that only a small percentage of the total... 

Gabel, D. Foster, S. Fairchild, R. G. The monte-carlo simulation of the biological effect of the b-10(n,alpha)li-7 reaction in cells and tissue and its implication for boron neutron-capture therapy. Radiat. Res. 1987, 111, 14-25. 

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