Dose verification of volumetric modulation arc therapy by using a NIPAM gel dosimeter combined with a parallel-beam optical computed tomography scanner

Volumetric modulated arc therapy (VMAT) was developed to shorten treatment time and increase target conformance. However, a true three-dimensional (3D) gel dosimeter is needed for dose verification. In this study, two clinic cases were adopted: a simple case of lung cancer and a complex case of larynx cancer. For each clinic case, two treatment plans were generated for the same planning target volume using VMAT and intensity modulated radiation therapy calculation software packages. An N-isopropylacrylamide (NIPAM) polymer gel dosimeter was used for 3D dose verification. In addition, the dose characteristics of the NIPAM gel dosimeter were investigated for the two clinic cases.

     

Automatic analysis for biochip based on macromolecular compound material

This paper illustrates a way of quantifying fluorescent chromogenic information through the image processing and identification, and analyzes the correlations between fluorescent chromogenic reaction and a probe. This analytical method is an important reference for probe development, and also used for analyzing the biochip interaction. The relationship between the same type but differing concentrations of probe and fluorescent images was derived. With light field analysis of probe attachment, we performed numerical analysis of the fluorescent signal in accordance with the method of biological area analysis. Through this method, biochips can simultaneously provide many types of quantitative and qualitative figures for research reference.     

Syntheses of 2-arylbenzothiazoles from flash vacuum pyrolyses and photolyses of 2-methylthio-N-(arenylidene)anilines

Flash vacuum pyrolyses and photolyses of 2-methylthio-N-(arenylidene)anilines 2a-h are new and convenient methods for the syntheses of 2-arylbenzothiazoles 1a-h.     

Syntheses and pyrolyses of benzofuran analogues of alpha-oxo-o-quinodimethane. A study on vinylcarbene-cyclopropene rearrangement

Flash vacuum pyrolyses (FVP) of benzoic 3-methyl-2-benzofurancarboxylic anhydride (12) and benzoic 2-methyl-3-benzofurancarboxylic anhydride (13) at 550 degrees C and ca. 10(-2) torr both give methylenebenzocyclobutenone (21) as the major product and indenone (22) as the minor one. A mechanism involving generation of alpha-oxo-o-quinodimethane 11 as the primary pyrolysis product from FVP of 13, followed by elimination of a CO molecule to give carbene 24, which undergoes a vinylcarbene-cyclopropene rearrangement and a ring contraction of the resulting carbene 23, is proposed to account for the observed results. The proposed mechanism is further supported by a deuterium-labeling study on FVP of (2-benzofuryl)methyl-alpha,alpha-d2 benzoate (28-d2).     

Synthesis of N,N-di(arylmethylidene)arylmethanediamines by flash vacuum pyrolysis of arylmethylazides

Flash vacuum pyrolysis of arylmethylazides 7a-d gave 2,4-diazapentadienes 5a-d in high yield (76-92%). The thermal cyclization of 5a-d gave cis-imidazolines 1a-d, further heating or Swern oxidation of 1a-d gave dehydrogenated products, imidazoles 2a-d.     

Syntheses and pyrolyses of furan analogues of α-oxo-o-quinodimethanes. Formation of methylenecyclobutenone and 1-buten-3-yne via a vinylcarbene-cyclopropene rearrangement

Flash vacuum pyrolyses (FVP) of benzoic 2-methyl-3-furoic anhydride (12) and benzoic 3-methyl-2-furoic anhydride (13) at 550 °C and ca. 10(-2) Torr both give methylenecyclobutenone (16) and 1-buten-3-yne (17) as the main products. A mechanism involving generation of furan analogues of α-oxo-o-quinodimethane, 10 and 11, from FVP of 12 and 13, respectively, followed by elimination of a CO molecule to give the respective carbenes 34 and 36 is proposed. Carbenes 34 and 36 are interconvertible via a cyclopropene intermediate 35. A ring contraction from 36 will give 16, whereas a ring-opening of 34 followed by elimination of a CO molecule then leads to 17. The proposed mechanism is supported by substituent- and deuterium-labeling study on FVP of the derivatives of 12.     

Structural Determination of the [4+2] Dimer of 2,3-Dimethylene-2,3-Dihydrothiophene from Deuterium Labeling Study

2,3-Dimethylene-2,3-dihydrothiophene (1a), prepared by the flash vacuum pyrolysis of 3-methyl-2-thienylmethyl benzoate (7a), rapidly dimerizes to form a [4 + 2] dimer 6. The structure of the [4+2] dimer 6 was confirmed by comparing its NMR spectrum with that of the [4 + 2] dimers from 2-dideuteriomethylene-3-methylene-2,3-dihydrothiophene (1b) and 2-methylene-3-dideuteriomethylene-2,3-dihydrothiophene (1c).     

Synthesis of 1-Methyl-2,5-dimethylene-2,5-dihydropyrrole by the Flash Vacuum Pyrolysis of N-(1,5-Dimethyl-2-pyrryl)methyl Benzamide

Pyrolysis of N-(1,5-dimethyl-2-pyrryl)methyl benzamide (7) gaved a 1:1 ratio of 1-methyl-2,5-dimethylene-2,5-dihydropyrrole (4b) and 1,2-dimetbylpyrrole (10) as the primary pyrolysis products in 88% total yield. The reactive compound 4b was detected with low-temperature ¹H NMR spectroscopy. Upon warming, 4b reacted rapidly with 10 to give one-on-one, two-on-one and three-on-one adducts, 11, 12 and 13 , respectively.     

Pyrolytic Chemistry of Benzyl Benzoate

Flash vacuum pyrolysis of benzyl benzoate ( 3 ) at temperatures in the range 750–900 °C and at 10² torr gave diphcnylmethane ( 5 ) as the major product with toluene ( 6 ) and eight other trace products, namely bipbenyl ( 7 ), dibenzyl ( 8 ), 2-, 3-, 4-phenyltoluenes ( 9,10,11 , respectively), fluorcne ( 12 ), benzyl alcohol ( 4 ) and benzaldehyde ( 13 ). The mechanism of formation of these products is proposed to involve benzyl and phenyl radicals.     

Facile synthesis of reactive benzoazetinone by flash vacuum pyrolysis of isatoic anhydride

Pyrolysis of isatoic anhydride (3) at 550°C and ca. 1×10⁻² torr gave benzoazetinone (1, 80%) as the only product. The existence of 1 was confirmed by low-temperature NMR spectroscopy at −90°C. Above −20°C, 1 was converted to dimer (4, 50%), trimer (5, 22%), and anthranilic acid (6, 12%). Pyrolysis of 3 at 800°C and ca. 1×10⁻² torr gave 1-cyanocyclopentadiene (7) in 38% yield.