scholarly journals Free Radical Chemistry of White Phosphorus: γ-Irradiation of P4 in Bromoform

1968 ◽  
Vol 23 (7) ◽  
pp. 916-921 ◽  
Author(s):  
P. Airey ◽  
H. Drawe ◽  
A. Henglein
Keyword(s):  
Free Radicals ◽  
White Phosphorus ◽  
High Yield ◽  
Red Phosphorus ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Chain Reactions ◽  
Phosphorus Containing ◽  
High Yields ◽  
Free Radical Chemistry

CHBr2PBr2 and (CHBr2)2PBr are formed in high yields and in preparatively useful amounts when solutions of white phosphorus in bromoform are exposed to γ-radiation. In the first stages of irradiation, a red phosphorus containing many groups from the solvent is the only reaction product. About 1000 molecules of P4 are consumed per 100 eV of energy absorbed. In the later stages of irradiation, free radicals from the solvent attack this red phosphorus and lead to the formation of bromophosphines in high yield. Chain reactions are formulated for the formation of both the red phosphorus and the bromophosphines.

γ-strahlenchemische Reaktionen des weißen Phosphors in Cyclohexan- und Cyclohexan-Tetrachlorkohlenstoff-Lösung

1964 ◽  
Vol 19 (7) ◽  
pp. 549-557 ◽  
Author(s):  
K.-D. Asmus ◽  
A. Henglein ◽  
G. Meissner ◽  
D. Perner
Keyword(s):  
Organic Phosphorus ◽  
Phosphinic Acid ◽  
Reaction Scheme ◽  
White Phosphorus ◽  
Phosphorus Compounds ◽  
Reaction Products ◽  
Red Phosphorus ◽  
Γ Irradiation ◽  
Polymeric Form ◽  
Chain Reactions

Red phosphorus, soluble phosphorus organic compounds and small amounts of phosphine are formed when white phosphorus in cyclohexane solution is exposed to γ-rays. The red phosphorus contains one C6H11-group per 4 — 5 P-atoms. It reacts with chlorine to give cyclohexylphosphorusdichloride. Its reactivity towards oxygen can be decreased by high temperatures during irradiation or by high γ-doses. It is concluded from quantitative studies of this “annealing” process that phosphorus atoms carrying C6H11-endgroups are especially reactive in the polymeric form of phosphorus. The low molecular weight products of the reaction between white phosphorus and cyclohexane undergo typical reactions of tertiary phosphines. They can readily be oxidized and chlorinated to yield cyclohexyl-phosphinic-acid or cyclohexyl-phosphorus-dichloride, respectively. White phosphorus acts as a scavenger for free H-atoms and C6H11-radicals from the radiolysis of cyclohexane. This reaction, however, does generally not lead to the complete cracking of all PP-bonds of the P4-molecule.The following products are formed in the γ-irradiation of white phosphorus in cyclohexane in the presence of carbon tetrachloride: Red phosphorus containing C6H11- and CCl3-endgroups, cyclohexylphosphorus-dichloride, trichloromethyl-phosphorus-dichloride, chloroform, cyclohexyl-chloride, hexachloroethane and trichloromethyl-cyclohexane. The yields of these products at various doses, dose rates, temperatures and compositions of the solutions are described. Several products such as C6H11PCl2 are produced with high G-values at temperatures above 100°C. The results are explained by a reaction scheme in which three chain reactions simultaneously occur. They are linked together since they have a common intermediate in the form of the CCl3-radical. At high doses, the reaction products of phosphorus mentioned above (including the red phosphorus) are transformed into soluble organic phosphorus compounds of high boiling points the structure of which has not yet been recognized.

Die Reaktionen des weißen Phosphors mit Dimethyldisulfid unter γ-Bestrahlung

1968 ◽  
Vol 23 (7) ◽  
pp. 911-915 ◽  
Author(s):  
M. Scheffler ◽  
H. Drawe ◽  
A. Henglein
Keyword(s):  
Room Temperature ◽  
White Phosphorus ◽  
Red Phosphorus ◽  
Radiation Chemical ◽  
Γ Radiation ◽  
Chain Processes

Trimethylthiophosphite and red phosphorus are formed when solutions of white phosphorus in dimethyldisulfide are exposed to γ-radiation. The red phosphorus has a high content of CH3S groups. It is very reactive and can be converted into trimethylthiophosphite upon further irradiation in dimethyldisulfide suspension. Both the formation of red phosphorus from white phosphorus and the formation of trimethylthiophosphite from red phosphorus are chain processes. The radiation chemical yields are of the order of several 100 molecules/100 eV at room temperature.

Die Reaktion des weißen Phosphors mit Tetrachlorkohlenstoff unter dem Einfluß von Y-Strahlung, Licht und Wärme

1962 ◽  
Vol 17 (11) ◽  
pp. 703-711 ◽  
Author(s):  
D. Perner ◽  
A. Henglein
Keyword(s):  
Activation Energy ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Main Product ◽  
Thermal Reaction ◽  
White Phosphorus ◽  
Low Molecular Weight ◽  
Red Phosphorus ◽  
Γ Radiation ◽  
A Chain

Red phosphorus, phosphorus trichloride, trichloromethylphosphorus dichloride, hexachloroethane and a polymer consisting of carbon and chlorine are formed when solutions of white phosphorus in carbon tetrachloride are exposed to γ-radiation. Red phosphorus is the main product at room temperature. However, its yield rapidly decreases at higher temperatures and the yields of the low molecular weight products strongly increases. Typical G-values:The formation of the products PCl3 and CCl3PCl2 occurs by a chain reaction between phosphorus and carbon tetrachloride. A mechanism is proposed in which free radicals from the radiolysis of carbon tetrachloride attach the dissolved white phosphorus. The propagation of the chain is caused by chlorine transfer from carbon tetrachloride to partly trichloroalkylated or chlorinated phosphorus chains or rings. The activation energy of this transfer is found to be equal to 8.2 kcal/mole. This reaction with carbon tetrachloride is favored at high temperature while the competing process of the combination of those intermediate phosphorus chains and rings to give red phosphorus prodominates at low temperature. The red phosphorus formed contains one CCl3 group per 7 atoms of phosphorus. It was possible to synthesize trichloromethylphosphorus dichloride, trichloromethylphosphorus tetrachloride and trichloromethylphosphorus dibromide by treating the red phosphorus with chlorine or bromine, respectively.The thermal reaction between phosphorus and carbon tetrachloride also leads to PCl3 and CCl3PCl2 (ratio 1:3). Small amounts of red phosphorus and C2Cl6 could be traced too. The activation energy of the thermal reaction amounts to 22.2 kcal/moles. The photo reaction (visible light) leads to the same products. However, red phosphorus still is the main product at 100°C.

The radiolysis of gaseous trifluoromethyl iodide

1970 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
Author(s):  
PG Shah ◽  
DR Stranks ◽  
R Cooper
Keyword(s):  
Nitric Oxide ◽  
Free Radicals ◽  
Major Part ◽  
Decomposition Mechanism ◽  
Short Chain ◽  
Chain Reactions ◽  
Ion Clusters ◽  
High Yields

γ-Radiolysis of gaseous CF3I produces CF4 (G = 0.77), C2F6 (G = 3.0), C2F4 (G = O.89), and 12 (G = 4.08). In the presence of nitric oxide or bromine, the fluorocarbon products are removed and high yields of scavenged products are obtained. In the presence of NO, G(I2) is 11.6; in the presence of Br2, G(CF3Br) is 20.1. Competition experiments using Br2 and Cl2 indicate that thermal free radicals are responsible for a major part of the decomposition mechanism. The high radical yields may be due to short chain reactions involving excited iodine atoms or recombination of ion clusters.

scholarly journals Influence of a Modified Plant Extract on Activity of Antioxidant Enzymes and Concentration of Pigments in Gamma-Irradiated Plants of Maize and Wheat

2018 ◽  
Vol 72 (1) ◽  
pp. 38-42
Author(s):  
Ibrahim Azizov ◽  
Elshan Shamilov ◽  
Asim Abdullayev ◽  
Zohra Muslimova ◽  
Gunel Mamedli ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Free Radicals ◽  
Plant Extract ◽  
Photosynthetic Pigment ◽  
Average Dose ◽  
Γ Irradiation ◽  
Dose Power ◽  
Γ Radiation ◽  
Gamma Irradiated ◽  
Object Of Study

Abstract The influence of a medicinal plant extract, immobilised by ligands, on the activity of antioxidant enzymes and photosynthetic pigment concentration of wheat and maize was studied. The object of study was seed of drought-resistant firm durum wheat (Triticum durum Desf.) and maize (Zea mays L.). Seeds were subjected to general uniform γ-radiation from a 60Co source on a Rkhund installation at average dose power of MD = 0.306 Gy/sec. Before radiation seeds were treated in modified extract from medicinal plants. The treatment of seeds with 0.1 and 0.01% solution of modified extract from Hypericum, Dandelion, and Calendula caused significant reduction in processes initiated by radiation and in formation of free radicals. On the basis of the obtained results it was concluded that the used modified plant extract collection had a protective effect, reducing the amount of free radicals produced by γ-irradiation.

Evaluation of germ plasm for resistant to Soybean mosaic virus (SMV)

2020 ◽  
Vol 21 (1) ◽  
pp. 6-9
Author(s):  
Wuye Ria Andayanie
Keyword(s):  
Abiotic Stress ◽  
Environmental Factors ◽  
Mosaic Virus ◽  
Polyclonal Antibody ◽  
Symptom Severity ◽  
Germ Plasm ◽  
Polyclonal Antibodies ◽  
Soybean Mosaic Virus ◽  
High Yield ◽  
High Yields

Soybean superior varieties with high yields and are resistant to abiotic stress have been largely released, although some varieties grown in the field are not resistant to SMV. In addition, the opportunity to obtain lines of hope as prospective varieties with high yield and resistance to SMV is very small. The method for evaluating soybean germplasm is based on serological observations of 98 accessions of leaf samples from SMV inoculation with T isolate. The evaluation results of 98 accessions based on visual observations showed 31 genotypes reacting very resistant or healthy to mild resistant category to SMV T isolate  with a percentage of symptom severity of 0 −30 %. Among 31 genotypes there are 2 genotypes (PI 200485; M8Grb 44; Mlg 3288) with the category of visually very resistant and resistant, respectively and  Mlg 3288  with the category of mild resistant.  They have a good agronomic appearance with a weight of 100 seeds (˃10 g) and react negatively with polyclonal antibodies to SMV, except Mlg 3288 reaction is not consistent, despite the weight of 100 seeds (˃ 10 g). Leaf samples from 98 accessions revealed various symptoms of SMV infection in the field. This diversity of symptoms is caused by susceptibility to accession, when infection occurs, and environmental factors. Keywords—: soybean; genotipe; Soybean mosaic virus (SMV); disease severity; polyclonal  antibody

scholarly journals Performance of Strawberry Varieties Developed for Perennial Matted-Row Production in Annual Plasticulture in a Cold Climate Region

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1407
Author(s):  
Courtney A. Weber
Keyword(s):  
Large Scale ◽  
Fruit Size ◽  
Weather Conditions ◽  
Cold Climate ◽  
Annual Production ◽  
High Yield ◽  
Production Cycle ◽  
Late Season ◽  
Berry Weight ◽  
High Yields

Annual plasticulture production of strawberries promises superior weed control, fruit quality and yields. However, strawberry varieties adapted for perennial, matted-row production and local markets in cold climate regions have not been widely tested for adaptation to an annual production cycle. Productivity of seven short-day varieties developed for matted-row and/or annual production was examined in an annual plasticulture system in two consecutive trials in central NY (lat. 42.87° N, long. 76.99° W) harvested in 2013 and 2014. ‘Flavorfest’ demonstrated good performance in Trial 1 with high yield (390 g/plant) and large fruit size (13.9 g mean berry weight). ‘Jewel’ was shown to be well adapted to the annual plasticulture system with consistently high yields (330 and 390 g/plant) that equaled or surpassed other varieties and had moderate fruit size. ‘Chandler’ performed similarly to previous trials conducted in warmer regions with yield (340 g/plant) and fruit size (9.8 g mean berry weight) similar to ‘Jewel’. ‘Clancy’ yielded less but was consistent from year to year. The late season varieties Seneca and Ovation showed marked variability between years, possibly due to drastically different temperatures during flowering and fruit development in Trial 1 compared to Trial 2. High temperatures in Trial 1 likely caused higher early fruit yield, a compressed season and a precipitous decline in fruit size in the later season, thus reducing yield in the late season. Survival after a second dormant period was poor resulting in a small second harvest and reduced fruit size. Overall, the system demonstrated many of the expected benefits but may be more sensitive to weather conditions in the region. While many varieties developed for matted-row production may work well in an annual plasticulture system, not all varieties are equally adapted. Performance of each variety should be determined independently before large scale adoption by growers.

Direct conversion of cellulose to high-yield methyl lactate over Ga-doped Zn/H-nanozeolite Y catalysts in supercritical methanol

2017 ◽  
Vol 19 (8) ◽  
pp. 1969-1982 ◽  
Author(s):  
Deepak Verma ◽  
Rizki Insyani ◽  
Young-Woong Suh ◽  
Seung Min Kim ◽  
Seok Ki Kim ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Value Added ◽  
Direct Conversion ◽  
High Yield ◽  
Supercritical Methanol ◽  
Methyl Lactate ◽  
High Yields

For realizing sustainable bio-based refineries, it is crucial to obtain high yields of value-added chemicalsviadirect conversion of cellulose and lignocellulosic biomass.

scholarly journals Multi-curie production of gallium-68 on a biomedical cyclotron and automated radiolabelling of PSMA-11 and DOTATATE

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Helge Thisgaard ◽  
Joel Kumlin ◽  
Niels Langkjær ◽  
Jansen Chua ◽  
Brian Hook ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
High Yield ◽  
Clinical Use ◽  
Automated Production ◽  
Automated Method ◽  
Gallium 68 ◽  
High Yields ◽  
High Level ◽  
Mev Protons ◽  
Very High

Abstract Background With increasing clinical demand for gallium-68, commercial germanium-68/gallium-68 ([68Ge]Ge/[68Ga]Ga) generators are incapable of supplying sufficient amounts of the short-lived daughter isotope. In this study, we demonstrate a high-yield, automated method for producing multi-Curie levels of [68Ga]GaCl3 from solid zinc-68 targets and subsequent labelling to produce clinical-grade [68Ga]Ga-PSMA-11 and [68Ga]Ga-DOTATATE. Results Enriched zinc-68 targets were irradiated at up to 80 µA with 13 MeV protons for 120 min; repeatedly producing up to 194 GBq (5.24 Ci) of purified gallium-68 in the form of [68Ga]GaCl3 at the end of purification (EOP) from an expected > 370 GBq (> 10 Ci) at end of bombardment. A fully automated dissolution/separation process was completed in 35 min. Isolated product was analysed according to the Ph. Eur. monograph for accelerator produced [68Ga]GaCl3 and found to comply with all specifications. In every instance, the radiochemical purity exceeded 99.9% and importantly, the radionuclidic purity was sufficient to allow for a shelf-life of up to 7 h based on this metric alone. Fully automated production of up to 72.2 GBq [68Ga]Ga-PSMA-11 was performed, providing a product with high radiochemical purity (> 98.2%) and very high apparent molar activities of up to 722 MBq/nmol. Further, manual radiolabelling of up to 3.2 GBq DOTATATE was performed in high yields (> 95%) and with apparent molar activities (9–25 MBq/nmol) sufficient for clinical use. Conclusions We have developed a high-yielding, automated method for the production of very high amounts of [68Ga]GaCl3, sufficient to supply proximal radiopharmacies. The reported method led to record-high purified gallium-68 activities (194 GBq at end of purification) and subsequent labelling of PSMA-11 and DOTATATE. The process was highly automated from irradiation through to formulation of the product, and as such comprised a high level of radiation protection. The quality control results obtained for both [68Ga]GaCl3 for radiolabelling and [68Ga]Ga-PSMA-11 are promising for clinical use.

Investigating Benzene and Metabolite Mediated Alterations in Nrf2 Signaling in Murine Fetal Liver Cells

2018 ◽  
Author(s):  
Enoch Lam
Keyword(s):  
Free Radicals ◽  
Cell Cultures ◽  
Childhood Leukemia ◽  
Fetal Liver ◽  
White Blood Cells ◽  
Chemical Exposure ◽  
The Body ◽  
Chain Reactions ◽  
Additional Cell ◽  
Other Substances

Leukemia is a cancer of the blood, where the body produces an overabundance of immature white blood cells. It is the most common childhood cancer and possibly originates from chemical exposure during fetal development. Understanding the molecular mechanism and causes of childhood leukemia will help the development of therapeutic and preventative strategies to reduce and treat occurrences of this cancer. Benzene is a non-polar aromatic ring that has been confirmed to cause leukemia in adults. Benzene metabolites can generate free radicals that could potentially be involved in the development of childhood leukemia through in utero exposures. It is found in tobacco smoke, gasoline, industrial solvents and many other substances. Pregnant mothers can be chronically exposed to these substances through daily activities. In order to help determine the mechanism of benzene toxicity, a study was performed to determine the presence of free radicals in the livers of fetal mice at gestation day 14. Fetal liver cell cultures were exposed to varying concentrations of benzene and additional cell cultures were exposed to various concentrations of a benzene metabolite mixture, composed of hydroquinone and benzoquinone. RNA was extracted from these cells and converted into complementary DNA. cDNA was then used in quantitative polymerase chain reactions to analyze a set of genes that are regulated by an antioxidant pathway. This pathway can be activated in response to oxidative stress, and a change in gene expression would indicate the presence of benzene or benzene metabolite toxicity in the liver at gestation day 14.

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