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Pochodne L-tyrozyny jako leki oraz znaczniki do obrazowania nowotworów

Pająk Małgorzata

Przemysł Chemiczny

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2020

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T. 99, nr 10

1541--1545

PL

L-Tyrozyna jest prekursorem związków biologicznie aktywnych, a jej zaburzony metabolizm prowadzi do wielu schorzeń, w tym do choroby Parkinsona i albinizmu. W ostatnim czasie wzrosło zainteresowanie syntezą znakowanych izotopowo halogenowych i metylowych pochodnych tego aminokwasu o potencjalnym zastosowaniu w medycynie nuklearnej. Przed wprowadzeniem nowego związku do organizmu chorego ważne jest, aby prześledzić jego wpływ na reakcje szlaku metabolicznego L-tyrozyny. Dokonano przeglądu obecnie stosowanych radiofarmaceutyków, będących pochodnymi L-tyrozyny, oraz omówiono ich wpływ na reakcje enzymatyczne, w których bierze udział ten aminokwas.

EN

A review, with 41 refs., of currently used radiopharmaceuticals and particularly of labeled halogenated and methylated derivatives of L-tyrosine used as potential radiotracers for nuclear medicine.

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Studies on hydrometallurgical processes using nuclear techniques to be applied in copper industry. 2. Application of radiotracers in copper leaching from fl otation tailings

Rogowski M., Smoliński T., Pyszynska M., Brykała M., Chmielewski A. G.

Nukleonika

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2018

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Vol. 63, No. 4

131--137

EN

The use of radiotracers in the present study is intended to replace traditional steps of metal quantitative analysis (solution sampling and instrumental chemical analysis) and to allow real-time measurements of metal concentrations during the leaching process. In this study, 64Cu, an isotope of copper, was selected as a radiotracer. Samples of copper flotation tailings were irradiated in the Maria research reactor (Świerk, Poland) and mixed with an inactive portion of the milled flotation waste. The leaching process was carried out in a glass reactor, and the radiation spectrum was measured using a gamma spectrometer. The material was then treated using various acids (sulphuric acid, nitric acid, acetic acid, citric acid, and ascorbic acid) in a wide range of their concentrations. Experiments with the radiotracer were conducted in sulphuric and nitric acids. The amount of the leached metal (copper) was calculated on the basis of the peak area ratio in the gamma-ray spectrum of the activated tailings and standard samples. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to analyse the metal content. Maximum recovery of 56% Cu was achieved using 9 M HNO3, whereas the recovery was lowest for ascorbic acid (1%). Both analytical methods were compared, and the results presented in this paper are in good agreement with radiometric measurements obtained using ICP-MS analysis.

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Radiotracer investigation of a pulp and paper mill effl uent treatment plant

Sarkar M., Sangal V. K., Bhunia H., Bajpai P. K., Pant H. J., Sharma V. K., Kumar A., Naithani A. K.

Nukleonika

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2017

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Vol. 62, No. 4

289--294

EN

The pulp and paper industry is highly dependent on water for most of its processes, producing a significant amount of wastewater that should be treated to comply with environmental standards before its discharge into surface-water reservoirs. The wastewater generated primarily consists of substantial amounts of organic, inorganic, toxic and pathogenic compounds in addition to nutrients, which are treated in an effluent treatment plant that often combines primary, secondary, tertiary and advanced treatments. However, the treatment methods vary from industry to industry according to the process utilized. The effective performance of effluent treatment plants is crucial from both environmental and economic points of view. Radiotracer techniques can be effectively used to optimize performance and detect anomalies like dead zones, bypassing, channelling, etc. in wastewater treatment plants. Experiments on the distribution of residence time were performed on the aeration tank and secondary clarifier of a full-scale pulp and paper mill to study the flow behaviour as well as locate system anomalies and hence evaluate the performance of the treatment plants using the radiotracer I-131. The convolution method was applied to model the system with an imperfect impulse radiotracer input. The aeration tank was working efficiently in the absence of any dead zones or bypassing. Various hydrodynamic models available in the literature were applied on the aeration tank and secondary clarifier to obtain the hydraulic representation of the systems.

4

Flow dynamics study of catalyst powder in catalytic cracking unit for troubleshooting

Yelgaonkar V., Agrahari G., Vikrant D., Prasanna R., Pathak B. K.

Nukleonika

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2017

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Vol. 62, No. 4

277--283

EN

Gamma scanning and radiotracer applications are very effective and inexpensive tools to understand and optimize the process as well as troubleshoot the various types of problems in many chemical, petrochemical industries and refineries. These techniques are non-invasive; hence, the problems can be pinpointed online, which leads to reduce the downtime, schedule the shutdown and maintenance of the plant equipment, rendering huge economic benefits. In a leading refinery of India, the catalytic cracking unit (CCU) was malfunctioning. It was suspected by the refinery engineers that the catalyst powder was being carried over to the fractionator, which could have led to erosion of the fractionator column internals resulting in their rupture, and consequentially, to the fire hazard. To understand the flow behaviour of the catalyst powder and to ensure the mechanical integrity, catalyst accumulation and choking, both radiotracer study and gamma scanning of the CCU reactor was carried out. The reactor consists of a riser, three primary cyclones and three secondary cyclones. Gamma scanning of the reactor was carried out with the help of an automatic gamma scanner using 1.8 GBq of Co-60 sealed source. Results showed that the catalyst powder was accumulated in one of the secondary cyclones and uneven density distribution was observed in another secondary cyclone. The radiotracer study was carried out using the irradiated catalyst powder as a radiotracer, which contains 0.9 GBq of Na-24. The radiotracer was injected in the reactor through the specially fabricated injection system. Radiation measurement was done using the thermally insulated and collimated NaI(Tl) scintillation detectors located at various strategic locations coupled to a multi-detector data acquisition system. The data were mathematically analysed. It was confirmed that the catalyst powder was accumulated in one of the secondary cyclones with no flow downwards. This resulted in excess powder available to travel along with hydrocarbon towards fractionator. Since the quantity of powder released through the hydrocarbon outlet of CCU was higher than the designed value, the catalyst powder was observed in various zones of the fractionator. Mathematical modelling of the radiotracer data obtained at various locations corroborated the scanning results; also, the flow pattern was obtained. Partially blocked secondary cyclone showed plug flow with recirculation; normal working cyclone had plug flow behaviour and the vortex breaker showed parallel flow.

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Badania procesu fermentacji metanowej z wykorzystaniem metod radioznacznikowych i technik gamma skaningu

Palige J., Roubinek O., Wawryniuk K., Modzelewski Ł, Jakowiuk A., Dobrowolski A., Drewniak Ł., Ciężkowska M

Inżynieria i Aparatura Chemiczna

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2014

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Nr 4

280--281

PL

Określono metodami radioznacznikowymi, z wykorzystaniem trytu jako znacznika fazy ciekłej, rozkład czasu przebywania i średni czas retencji zawiesiny w bioreaktorach do produkcji biometanu. Wykorzystując technikę gamma skaningu określono objętość czynną fazy ciekłej, gazowej oraz obszar tworzenia się kożuchów.

EN

The residence time distribution and mean residence time of liquid phase in fermentor was determined using the tritium water as a radiotracer. With application of gamma scanning technique the volumes of liquid phase and foam in bioreactor were determined.

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Determination of flow patterns in industrial gold leaching tank by radiotracer residence time distribution measurement

Stęgowski Z., Dagadu C. P. K., Furman L., Akaho E. H. K., Danso K. A., Mumuni I. I., Adu P. S., Amoah C.

Nukleonika

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2010

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Vol. 55, No. 3

339-344

EN

The carbon-in-leach (CIL) process is one the most efficient methods of gold recovery from gold bearing ores. The efficiency of the leaching process greatly depends on the flow structure created by mechanical agitation (in some cases air agitation) in the leaching tanks. Residence time distribution (RTD) measurement was conducted in the CIL section of a gold processing plant in order to determine the flow structure in the first tank using the 131I radioactive tracer. The shape of the experimental data revealed that the flow behaviour in the tank was close to an ideal mixer. Modelling of the experimental data, however, revealed that the tank was not behaving as a single perfect mixer, but consisted of two mixing zones. The flow structure in the tank was best described by the “perfect mixers with exchange” model consisting of two mixing zones. The model allowed the determination of flow parameters including the mean residence time, flow rate and volumes of the mixing zones.

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Radiotracer investigations of municipal sewage treatment stations

Farooq M., Khan I., Ghiyas-ud-Din, Gul S., Palige J., Dobrowolski A.

Nukleonika

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2003

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Vol. 48, nr 1

57-61

EN

Tracer techniques, which are well-established methods in process dynamics studies in industry, were applied to investigate the dynamics of sewage treatment process. The concept of residence time distribution (RTD) was used to investigate the efficiency of the primary clarifier, aeration tank and secondary clarifier of a sewage treatment plant. Preliminary treatment and modeling of the tracer data was performed using the software DTS Pro Ver. 4.20. A big short - circuiting (by-passing) with a large volume of stagnant zones were found in the primary and secondary clarifiers, while no stagnant zone was detected in the aeration tank.