Measurement of excited singlet yields in .gamma.-radiolysis of benzene and ketones. Radiation-induced "type II" elimination of 4-methyl-4-phenyl-2-pentanone

1972 ◽  
Vol 76 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Bizhan M. Zarnegar ◽  
David G. Whitten
Keyword(s):  
Type Ii ◽  
Excited Singlet ◽  
Gamma Radiolysis ◽  
Radiation Induced

scholarly journals β-Catenin/Lin28/let-7 regulatory network determines type II alveolar epithelial stem cell differentiation phenotypes following thoracic irradiation

2020 ◽  
Vol 62 (1) ◽  
pp. 119-132
Author(s):  
Xiaozhuan Liu ◽  
Tingting Zhang ◽  
Jianwei Zhou ◽  
Ziting Xiao ◽  
Yanjun Li ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Stem Cell Differentiation ◽  
Alveolar Epithelial Cells ◽  
Type I ◽  
Type Ii ◽  
Epithelial Stem Cells ◽  
Alveolar Epithelial ◽  
Thoracic Irradiation ◽  
Radiation Induced ◽  
Differentiation Marker

Abstract The contribution of type II alveolar epithelial stem cells (AEC II) to radiation-induced lung fibrosis (RILF) is largely unknown. Cell differentiation phenotypes are determined by the balance between Lin28 and lethal-7 microRNA (let-7 miRNA). Lin28 is activated by β-catenin. The aim of this study was to track AEC II phenotypes at different phases of injury following thoracic irradiation and examine the expression of β-catenin, Lin28 and let-7 to identify their role in AEC II differentiation. Results showed that coexpression of prosurfactant protein C (proSP-C, an AEC II biomarker) and HOPX (homeobox only protein X, an AEC I biomarker) or vimentin (a differentiation marker) was detected in AEC II post-irradiation. The protein expression levels of HOPX and proSP-C were significantly downregulated, but vimentin was significantly upregulated following irradiation. The expression of E-cadherin, which prevents β-catenin from translocating to the nucleus, was downregulated, and the expression of β-catenin and Lin28 was upregulated after irradiation (P < 0.05 to P < 0.001). Four let-7 miRNA members (a, b, c and d) were upregulated in irradiated lungs (P < 0.05 to P < 0.001), but let-7d was significantly downregulated at 5 and 6 months (P < 0.001). The ratios of Lin28 to four let-7 members were low during the early phase of injury and were slightly higher after 2 months. Intriguingly, the Lin28/let-7d ratio was strikingly increased after 4 months. We concluded that β-catenin contributed to RILF by promoting Lin28 expression, which increased the number of AEC II and the transcription of profibrotic molecules. In this study, the downregulation of let-7d miRNA by Lin28 resulted in the inability of AEC II to differentiate into type I alveolar epithelial cells (AEC I).

The radiation-induced formation of excited states of aromatic hydrocarbons in alicyclic hydrocarbons I. Yields of excited singlet and triplet state solute molecules

1975 ◽  
Vol 347 (1648) ◽  
pp. 61-73 ◽  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Pulse Radiolysis ◽  
Minor Role ◽  
Intersystem Crossing ◽  
Excited Singlet ◽  
Excited Triplet ◽  
Upper Limit ◽  
Radiation Induced ◽  
A Minor

The dependences on concentration of the yield of excited triplet naphthalene, G ( 3 Naph٭), and of the radiation-induced fluorescence obtained on pulse radiolysis of solutions of naphthalene in cyclopentane, cyclooctane and decalin are reported. The yields of singlet excited naphthalene, G( 1 Naph٭), formed on pulse radiolysis of these solutions have been determined by comparing the intensity of the radiation-induced fluorescence with that obtained on photo excitation and the extent of formation of 3 Naph٭ by intersystem crossing, G ( 3 Naph٭) i. s. c., is assessed. Upper limit yields of solvent excited states, G ( 1 RH٭), were determined by measuring the extent of singlet energy transfer to toluene. It is concluded that energy transfer from solvent excited states plays a minor role in the formation of excited states of aromatic solutes.

scholarly journals Role of Type II Pneumocyte Senescence in Radiation-Induced Lung Fibrosis

2013 ◽  
Vol 105 (19) ◽  
pp. 1474-1484 ◽  
Author(s):  
Deborah E. Citrin ◽  
Uma Shankavaram ◽  
Jason A. Horton ◽  
William Shield ◽  
Shuping Zhao ◽  
...  
Keyword(s):  
Lung Fibrosis ◽  
Type Ii ◽  
Type Ii Pneumocyte ◽  
Radiation Induced

The radiation-induced formation of excited states of aromatic hydrocarbons in benzene and cyclohexane, II. Yields of excited singlet and triplet state solute molecules

1972 ◽  
Vol 328 (1575) ◽  
pp. 457-479 ◽  
Keyword(s):  
Excited States ◽  
Pulse Radiolysis ◽  
Singlet State ◽  
Relative Yield ◽  
Excited Singlet State ◽  
High Yield ◽  
Triplet States ◽  
Excited Singlet ◽  
Concentration Dependences ◽  
Radiation Induced

The concentration dependences of the yield of excited triplet states, G ( 3 S*), and the concentration dependences of the relative yield of radiation-induced fluorescence obtained on pulse radiolysis of solutions of naphthalene, anthracene, pyrene and 2,5-diphenyloxazole (PPO) are reported. The yields of excited singlet state solute molecules, G ( 1 S*), formed on pulse radiolysis of naphthalene-cyclohexane and naphthalene-benzene solutions has been determined by comparing the intensity of the radiation-induced fluorescence with that obtained on photo-excitation. It is concluded that intersystem crossing (i.s.c.) from the excited singlet state is an important process in the formation of the high yield of triplet excited states of the solute. Under certain conditions this process accounts for up to 50 % of G ( 3 S*) in cyclohexane and the entire G ( 3 S*) in benzene solutions.

Radiation induced secretion of surfactant from cell cultures of type II pneumocytes: An in vitro model of radiation toxicity

1984 ◽  
Vol 10 (3) ◽  
pp. 375-378 ◽  
Author(s):  
Donald L. Shapiro ◽  
Jacob N. Finkelstein ◽  
Philip Rubin ◽  
David P. Penney ◽  
Dietmar W. Siemann
Keyword(s):  
Cell Cultures ◽  
In Vitro Model ◽  
Radiation Toxicity ◽  
Type Ii ◽  
Type Ii Pneumocytes ◽  
Radiation Induced ◽  
Vitro Model
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