EFFECT OF HYPOTHERMIA ON THE CONTENT OF SUPEROXIDE ANION- RADICAL AND TBA-REACTIVE SUBSTANCES IN PLANT TISSUES

2021 ◽  
pp. 22-30
Author(s):  
Bobrova M. ◽  
Arkushyna H. ◽  
Vorona S.
Keyword(s):  
Free Radical ◽  
Antioxidant System ◽  
Solanum Tuberosum L ◽  
Active Form ◽  
Malonic Dialdehyde ◽  
Tissue Samples ◽  
Average Value ◽  
Allium Cepa L ◽  
The Difference ◽  
Edible Parts

The influence of stressors of different nature changes the state of the prooxidantand antioxidant system. The first and most aggressive active form of Oxygen is the superoxidation radical, the secondary product of free radical lipid peroxidation is malonic dialdehyde (MDA).Hypothermia is a necessary phenomenon for plants of temperate latitudes, and a necessary factor in extending the shelf life of edible vegetative parts of plants. The purpose of the study: toidentify changes in the value of prooxidant activity in the tissues of edible parts of agricultural plants under the influence of changes in temperature. Quantitative determination of prooxidants and products of free radical peroxidation was investigated on tissue samples of edible parts of the following plants: Allium cepa L. AlliumsativumL., BetavulgarisL., CapsicumannuumL., CucumissativusL., CucurbitapepoL., Daucus sativus (Hoffm.) Roehl., Lycopersicon esculentum Mill.s.l., SolanummelongenaL. SolanumtuberosumL. The level of superoxide generation was carried out by spectrophotometric HCT test, the level of MDA was determined by reaction with TBA. As a result of the research it was found that the average value of increasing the generation ofsuperoxide during cooling is 30.75%, during freezing -49.35%, but the difference in the average value of ∆MDA in different types of hypothermia is almost absent (growth is 22.12% during cooling and 23.73% during freezing), which may be due to a powerful system of antioxidant tissue protection. Solanum tuberosum L., Allium sativum L., Beta vulgaris L.are the most resistant,in terms of changes in the prooxidantand antioxidant system to hypothermia; Capsicum annuum L. andLycopersicon esculentum Mill.s.l.are the least resistant.The generative organs of plants are the least resistant to hypothermia than the vegetative ones. Freezing allows storing plant products for a longer time than refrigeration, however, chilled vegetables retain less prooxidants and products of free radical peroxidation in the tissues.Key words: superoxide, malonic dialdehyde, reactive oxygen species, free radical peroxidation, hypothermia. Вплив стресорів різної природи змінює показники стану прооксидантно-антиоксидантної системи. Першою та найбільш агресивною активною формою Оксигену є супероксиданіон радикал, вторинним продуктом вільнорадикального перекисного окиснення (ВРПО) ліпідів є малоновий діальдегід (МДА). Гіпотермія –обов’язкове явище для рослин помірних широт зростання, та необхідний фактор продовження терміну зберігання їстівних частин рослин. Мета дослідження: виявити зміни значення прооксидантної активності в тканинах їстівних частин сільськогосподарських рослин під впливом зміни температурного режиму. Кількісне визначення прооксидантів та продуктів ВРПО здійснювали узразках тканин їстівних частин таких рослин: AlliumcepaL. AlliumsativumL., BetavulgarisL., CapsicumannuumL., CucumissativusL., CucurbitapepoL., Daucussativus(Hoffm.) Roehl., LycopersiconesculentumMill.s.l., SolanummelongenaL. SolanumtuberosumL. Рівень генерації супероксиду здійснювали за спектрофотометричниим НСТ-тестом, рівень МДА визначали реакцією з ТБК. У результаті проведених досліджень виявлено, що середнє значення підвищення генерації супероксиду при охолодженні складає 30,75%, при заморожуванні –49,35%, однак різниця в середньому значенні ∆ МДА при різних видах гіпотермії практично відсутня (зростання складає 22,12% при охолодженні та 23,73% при заморожуванні), що може бути наслідком дії потужної системи антиоксидантного захисту тканин. Найбільш стійкими в плані зміни прооксидантно-антиоксидантної системидо гіпотермії є SolanumtuberosumL., AlliumsativumL., BetavulgarisL.; найменш стійкими -CapsicumannuumL. та LycopersiconesculentumMill.s.l. Генеративні органи рослин є найменш стійкими до дії гіпотермії ніж вегетативні. Заморожування дозволяє зберігати рослинну продукцію протягом більш тривалого часу ніж охолодження, однак, охолоджені овочі зберігають менше прооксидантів та продуктів ВРПО в тканинах.Ключові слова: супероксид, малоновий діальдегід, активні форми Оксигену, вільнорадикальне перекисне окиснення, гіпотермія

scholarly journals The effect of hypothermia on the state of the prooxidant-antioxidant system of plants

2021 ◽  
Vol 12 (33) ◽  
pp. 82-101
Author(s):  
Mariia Bobrova ◽  
Olena Holodaieva ◽  
Svitlana Koval ◽  
Olha Tsviakh ◽  
Olena Kucher
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Lycopersicum ◽  
Capsicum Annuum ◽  
Beta Vulgaris ◽  
Antioxidant System ◽  
Allium Sativum ◽  
Solanum Tuberosum L ◽  
The State ◽  
Solanum Lycopersicum L ◽  
Edible Parts

Aim of the research: to identify changes in the value of indicators of the state of the prooxidant-antioxidant system (PAS) in the tissues of edible parts of agricultural plants under the influence of temperature changes. Methodology: Quantitative determination of indicators of the state of PAS was performed on tissue samples of edible parts of the following plants: Solánum lycopérsicum L., Сucumis sativus L., Capsicum annuum L., Solanum melongena L., Solanum tuberosum L., Allium sativum L., Allium cepa L., Daucus carota L., Beta vulgaris L., Cucurbita pepo var. Giraumontia L. The concentration of superoxide anion radical (•O2-), TBA-active products, superoxide dismutase (SOD) activity, catalase, the concentration of ascorbic acid (AA), glutathione (GSH) were determined. The results of the research show that hypothermia activates both parts of the PAS, however, cooling is accompanied by more powerful both low molecular weight and enzymatic antioxidant (AO) protection. The research of AO can be divided according to the degree of reduction of the protective value in hypothermia in the following series: SOD, catalase, GSH, AA. The most resistant in terms of changes in PAS to hypothermia is Solanum tuberosum L., Allium sativum L., Beta vulgaris L.; the least resistant is Capsicum annuum L., and Solánum lycopérsicum L. The generative organs of plants are less resistant to hypothermia than the vegetative ones. Practical consequences. As a result of the conducted biochemical analysis, it is established which method of storage of plant products is more effective in terms of preservation of AO activity: cooling or freezing.

The Effect of Jigsaw Methode and Motivation on Students’ of Learning Outcomes

2020 ◽  
Vol 3 (1) ◽  
pp. 20-30
Author(s):  
Yunita Yunita ◽  
Hidayat Hidayat ◽  
Harun Sitompul
Keyword(s):  
Cooperative Learning ◽  
Student Learning ◽  
Learning Outcomes ◽  
Student Learning Outcomes ◽  
Learning Motivation ◽  
Learning Approaches ◽  
High Learning ◽  
Average Value ◽  
The Difference ◽  
Low Motivation

This study aims to: (1) investigate the effect of Jigsaw cooperative learning on students learning outcomes; (2) find the difference in learning outcomes between high and low learning motivation and (3) find the interaction between learning approaches and learning motivation towards learning outcomes. The population of the study is students of grade IVa, IVb, IVc at SD Kasih Ibu Patumbak and the sample in this study is grade IVa with 35 students and grade IVb with 35 students. The results show that: (1) the average student learning outcomes of jigsaw cooperative learning is 28.40 while conventional is 24.14. Thus, students learning outcomes that get cooperative learning of jigsaw type are higher than conventional learning, (2) Students who have high motivation get an average value = 30.74, while low motivation is 22.72. Thus, it can be concluded that there are differences in student learning outcomes having high learning motivation and low learning motivation, and (3) students learning outcomes  taught by jigsaw cooperative learning are high learning motivation groups (32.94), and low learning motivation groups (24.58), while students taught with conventional learning are high learning motivation groups (28.40 ), and low motivation groups (20,95). Thus, there is no interaction between learning approaches and learning motivation towards learning outcomes.

Effect of 1,3,6-trimethyl-5-hydroxyuracil succinate on the antioxidant system and free-radical processes in the liver of adult and old rats treated with carbon tetrachloride

2018 ◽  
pp. 55-59
Author(s):  
И.Д. Габдрахманова ◽  
В.А. Мышкин ◽  
Д.А. Еникеев ◽  
А.Р. Гимадиева
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Carbon Tetrachloride ◽  
Antioxidant System ◽  
Complex Compound ◽  
Antiradical Activity ◽  
Conjugated Dienes ◽  
Experimental Animals ◽  
Old Rats ◽  
Radical Processes

Цель исследования: изучение влияния сукцината 1,3,6-триметил-5-гидроксиурацила на антиоксидантную систему и свободнорадикальные процессы в печени взрослых и старых крыс при воздействии тетрахлорметана. Методика. В эксперименте использованы половозрелые животные 12-месячного возраста со средней массой 250 г и старые животные 24-месячного возраста, средней массой 395 г по 30 особей в каждой возрастной группе. Токсическое поражение печени вызывали подкожным введением 50%-ного масляного раствора тетрахлорметана (ТХМ, 2 г/кг) в течение 4 сут. Одновременно с токсикантом опытным животным внутрибрюшинно вводили водный раствор коплексного соединения сукцинат-1,3,6-триметил-5-гидроксиурацила (2,5 мг/100 г) 3 раза в сут. в течение первых 4 сут. и в течение последующих 3 сут. 1 раз в сут. Контролем служили опытные животные, которым вводили физиологический раствор в том же объеме. Изучали окислительную модификацию белков, перекисное окисление липидов (по содержанию ТБК-реагирующих продуктов, уровню гидроперекисей липидов и содержанию диеновых конъюгатов). Состояние антиоксидантной системы оценивали по активности ферментов супероксиддисмутазы, каталазы и глутатионпероксидазы, определяемых биохимическими методами. Антирадикальную активность комплексного соединения и его составляющих субстанций исследовали в модельной системе «этилбензол-ледяная уксусная кислота» с вычислением константы К - скорости взаимодействия перекисных радикалов с молекулами изучаемого соединения в сравнении с эталонным антиоксидантом-ионолом с витамином Е. Результаты. Сукцинат + 1,3,6-триметил-5-гидрокси-урацила существенно снижает токсическое действие ТХМ на печень взрослых и старых крыс, устраняет дисбаланс в системах свободнорадикального окисления белков у старых крыс, статистически значимо улучшает показатели свободнорадикального окисления (СРО) липидов в печени взрослых и старых крыс: снижает уровень продуктов ПОЛ - гидроперекисей, диеновых конъюгатов, ТБК-реагирующих продуктов, а также улучшает работу антиоксидантной системы (АОС), повышая активность каталазы, супероксиддисмутазы и глутатионпероксидазы. Установлена высокая антирадикальная активность изучаемого препарата сопоставимая с активностью эталонного антиоксиданта ионола. Заключение. Сукцинат и его производные способны выступать как индивидуальные вещества с непосредственным антирадикальным механизмом действия, а не только как стимуляторы ферментативных систем антиоксидантной защиты. Aim. To study the effect of a complex compound, 1,3,6-trimethyl-5-hydroxyuracil succinate, on the antioxidant system and free radical processes induced by carbon tetrachloride in the liver of adult and old rats. Methods. The study used sexually mature animals aged 12 months and weighing 250 g and old animals aged 24 months weighing 395 g (total n= 60, 30 rats in each age group). Toxic damage of liver was induced by subcutaneous injections of a 50% oil solution of carbon tetrachloride (CTC) at 2 g/kg for 4 days. Together with the toxicant, experimental animals were injected with a water solution of a complex compound, succinate 1,3,6-trimethyl-5-hydroxyuracil, at a dose of 2.5 mg/100 g, i.p., 3 times per day for the first 4 days and once daily for the following 3 days. Experimental animals were used as controls, which were administered saline in the same volume. Oxidative modifications of proteins, lipid peroxidation (by levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and conjugated dienes) were studied. Condition of the antioxidant system was evaluated by activities of superoxide dismutase, catalase, and glutathione peroxidase using biochemical methods. Antiradical activity of the complex compound and its components was studied in a model system of ethylbenzene-glacial acetic acid; the K7 constant of the rate of peroxide radical interaction with molecules of the studied compound was compared with the reference antioxidant ionol with vitamin E. Results. Succinate +1.3.6-trimethyl-5-hydroxyuracil, considerably reduced TXM hepatotoxicity in adult and old rats; removed the disbalance in free radical systems of protein oxidation in old rats; significantly improved indexes of free-radical oxidation (FRO) of hepatic lipids in adult and old rats; decreased levels of LP products, hydroperoxides, conjugated dienes, and TBARS, and enhanced performance of the antioxidant system (AOS) by increasing activities of catalase, superoxide dismutase, and glutathione peroxidase. The study demonstrated a high antiradical activity of the study drug comparable with the activity of the reference antioxidant, ionol. Сonclusion. Succinate and its derivatives can perform as individual substances with a direct antiradical mechanism of action rather than as stimulators of enzymic systems of antioxidant defence.

Pengaruh Jumlah Pencucian Beras dengan Kadar Klorin

2017 ◽  
Vol 1 (1) ◽  
pp. 89
Author(s):  
Indah Purwaningsih ◽  
Supriyanto Supriyanto
Keyword(s):  
Mucous Membrane ◽  
Confidence Level ◽  
Iodometric Titration ◽  
Titration Method ◽  
Anova Test ◽  
Average Value ◽  
Significant Difference ◽  
The Difference

Abstract: Chlorine is a green halogen-shaped halogen gas at normal temperature and serves as bleach, stain remover and disinfectant. Chlorine is now widely used for bleaching rice so that less quality rice looks like quality rice. Chlorine is very toxic and causes mucous membrane irritation, highly reactive and very powerful oxidizer. The purpose of this research was to determine the difference of chlorine level in chlorinated rice washed once, twice and 3 times. The sample in this study amounted to 11 samples calculated by replication formula. Each sample was treated 3 times, ie 1 washed once, 2 washed twice and washed 3 times. The samples then examined by iodometric titration method. Based on the results of the study using ANOVA test, 11 samples obtained the average value of chlorine after washed once amount of 0.0176%, after washed twice amount of 0.0111%, and after washed 3 times amount of 0.0052% with the value significance p = 0.03 (p <0.05) at 95% confidence level which means there was a significant difference between chlorine levels in chlorinated rice washed once, twice and 3 times.Abstrak: Klorin merupakan unsur halogen berbentuk gas berwarna kuning kehijauan pada suhu normal danberfungsi sebagai pemutih, penghilang noda maupun desinfektan. Klorin sekarang banyak digunakan untuk bahan pemutih beras agar beras yang kurang berkualitas tampak seperti beras berkualitas. Klorin sangat toksik dan menyebabkan iritasi membran mukosa, sangat reaktif dan merupakan oksidator yang sangat kuat. Tujuan dari penelitian ini ialah untuk mengetahui perbedaan kadar klorin pada beras berklorin yang dicuci sebanyak 1 kali, 2 kali dan 3 kali. Sampel dalam penelitian ini berjumlah 11 sampel yang dihitung dengan rumus replikasi. Setiap sampel diberi perlakuan sebanyak 3 kali, yaitu 1 kali pencucian, 2 kali pencucian dan 3 kali pencucian. Sampel penelitian kemudian diperiksa dengan metode titrasi iodometri. Berdasarkan hasil penelitian menggunakan uji Anova secara komputerisasi terhadap 11 sampel diperoleh nilai rata-rata kadar klorin setelah 1 kali pencucian sebesar 0,0176 %, setelah 2 kali pencucian sebesar 0,0111 %, dan setelah 3 kali pencucian sebesar 0,0052 % dengan nilai signifkansi p = 0,03 (p<0,05) pada tingkat kepercayaan 95% yang artinya ada perbedaan yang bermakna antara kadar klorin pada beras berklorin yang dicuci sebanyak 1 kali, 2 kali dan 3 kali.

Results of studying the dimensional accuracy of the bases of complete removable prostheses made using 3D printing and traditional technologies

2020 ◽  
pp. 34-39
Author(s):  
Vokulova Yu.A. Vokulova ◽  
E.N. Zhulev
Keyword(s):  
3D Printing ◽  
Traditional Method ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Digital Technologies ◽  
Dimensional Accuracy ◽  
3D Printer ◽  
Significance Level ◽  
Average Value ◽  
The Difference

This article presents the results of studying the dimensional accuracy of the bases of complete removable prostheses made using a 3D printer and the traditional method. Bases of complete removable prostheses were made using an intraoral laser scanner iTero Cadent (USA) and a 3D printer Asiga Max UV (Australia). To study the dimensional accuracy of the bases of complete removable prostheses, we used the DentalCAD 2.2 Valletta software. The Nonparametric Wilcoxon W-test was used for statistical analysis of the obtained data. We found that the average value of the difference with the standard for bases made using digital technologies is 0.08744±0.0484 mm. The average value of the difference with the standard for bases made by the traditional method is 0.5654±0.1611 mm. Based on these data, we concluded that the bases of complete removable prostheses made using modern digital technologies (intraoral laser scanning and 3D printer) have a higher dimensional accuracy compared to the bases of complete removable prostheses made using the traditional method with a significance level of p<0.05 (Wilcoxon's W-test=0, p=0.031). Keywords: digital technologies in dentistry, digital impressions, intraoral scanner, 3D printing, ExoCAD, complete removable dentures.

scholarly journals PSX-3 Antioxidant system characteristics in Saanen goats depending on performance

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 461-462
Author(s):  
Polina D Bokhan ◽  
Alesya A Bakhta ◽  
Larisa Y Karpenko ◽  
Anna I Kozitcyna ◽  
Anna B Balykina ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Free Radical ◽  
Milk Yield ◽  
Antioxidant System ◽  
Free Radical Oxidation ◽  
Dairy Goat ◽  
Blood Levels ◽  
Lactation Performance ◽  
Radical Oxidation ◽  
System Characteristics

Abstract Dairy goat breeding is widespread worldwide. Goat milk and other derivative products are an important part of nutrition. Dairy products are the most important part of goat breeding; therefore, lactation performance is a relevant issue. The purpose of this study was to evaluate antioxidant system characteristics in Saanen goats depending on lactation performance. The experiment was conducted in the north-western region of Russian Federation, in the laboratories of the biochemistry and physiology departments at FSBEI of Higher Education «SPbSAVM». The three experimental groups included 30 Saanen goats each, 2nd–3rd lactations, selected using matched pairs method. 1st group included low milk producing ability goats (&lt; 600 kg of milk yield per year), 2nd group included average milk producing ability goats (600–800 kg of milk yield per year), 3rd group included high milk producing ability goats (&gt;800 kg of milk yield per year). The blood samples were taken once: at peak lactation performance (45 days after parturition). The blood levels of lipid peroxygenation markers (malondialdehyde, dienketone and conjugated dienes) and superoxide dismutase and catalase activity were assessed by standard methods. Results presented as mean±standard error of the mean. Student’s t-test was used after proving normal distribution. Level of significance is labeled as P &lt; 0.05. The results are displayed in table 1 and 2. After analyzing the received data of antioxidant system characteristics, we found a high intensity of free-radical oxidation in high milk producing ability goats. This results in oxidative stress development. Activity of anti-oxidizing enzymes was elevated; therefore, free-radical oxidation is intensive. Consequently, these data allow us to take into consideration exogenous anti-oxidizing agents administration in high milk producing ability goats in order to reduce oxidative stress.

Abstract P211: Single High Na + Ingestion Leads To An Increase In Oxidative Stress And Triggers Inflammation.

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Ginette Bordcoch ◽  
Ivan Tavera Busso ◽  
Juan Masjoan Juncos ◽  
Luis I Juncos
Keyword(s):  
Oxidative Stress ◽  
The United States ◽  
Male Rats ◽  
Control Group ◽  
Aortic Tissue ◽  
Tissue Samples ◽  
Extracellular Signal ◽  
High Prevalence ◽  
Markers Of Oxidative Stress ◽  
The Difference

Hypertension has been linked to a progressive increased in oxidative stress and inflammation. The high prevalence of hypertension poses a great risk to public health as 108 million adults in the United States have the condition. For that reason, a better understanding of the link between a high Na+ intake and the development of hypertension is of crucial importance. We hypothesize that a single ingestion of a high Na+ solution leads to increased oxidative stress and triggers an inflammatory response. Wistar 200-250 g male rats had gastric infusions through the esophagus. Groups were infused with 8 mL liquid Vaseline (Control), 8 mL of NaCl 0.684 M (4% m/v), and 8 mL of NaCl 1.368 M (8% m/v). After infusion, blood was collected at different time points during the first hour. Tissue samples were obtained from the aorta, heart, and kidney. Electron Microscopy (EM) was performed on all tissues, which were also analyzed for molecular markers of oxidative stress: Superoxide Dismutase (SOD) and Malondialdehyde (MDA), and an inflammation marker: Extracellular Signal-Regulated Kinase (ERK). At 2 and a half minutes, serum Na+ concentration was unchanged in the control group compared to an increase observed in animals receiving 4% and 8% Na+ with concentrations of 135±1.4 mEq/L, 141±2.0 mEq/L, and 140±1.2 mEq/L respectively. At the 1-hour time point after infusion, the difference was further increased in the 8% group with serum concentrations of 135±1.8 mEq/L, 140±1.5 mEq/L, and 152±1mEq/L respectively (p<0.05). There was an increase in oxidative stress in the aorta from values of 36.22±4.64 mU/mg SOD and 0.131±0.013 pg/mL MDA in the control group, to 47.11±4.89 mU/mg SOD and 0.291±0.022 pg/mL MDA in the 8% group (p<0.05 in both cases). The same was observed in the heart, where values were: 174.6125.26 mU/mg SOD, 0.026±0.007 pg/mL MDA in controls, and 259.22±21.98 mU/mg SOD, 0.215±0.073 pg/mL MDA in 8% group (p<0.05 both cases). Increased ERK in aortic tissue, values of 0.29±0.03 pg/mL in controls, 2.68±0.18 pg/mL in 4% group and 3.97±0.68pg/mL in 8% group (p<0.05) suggest increased inflammation. We conclude that the elevation in serum Na+ concentration that follows Na+ ingestion leads to increased oxidative stress and inflammation.

Electronic irradiation of TlInSxSe2−x (x = 1): Morphology, structure and raman scattering

2021 ◽  
Author(s):  
M. Yu. Tashmetov ◽  
F. K. Khallokov ◽  
N. B. Ismatov ◽  
I. I. Yuldashova ◽  
S. Kh. Umarov
Keyword(s):  
Surface Morphology ◽  
Single Crystal ◽  
Single Phase ◽  
Phase State ◽  
Monoclinic Structure ◽  
Average Value ◽  
Single Phase State ◽  
Before And After ◽  
Electronic Irradiation ◽  
The Difference

It is shown that the replacement of a part of sulfur atoms with selenium atoms in a TlInS2 single crystal stimulates the formation of a single-phase state with a monoclinic structure (space group [Formula: see text]/[Formula: see text] in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation with 2 MeV electrons and a fluence of [Formula: see text] electron/cm2 of powder TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) leads to an increase in the crystallite size from 56.5 nm to 65 nm, which is most likely associated with a decrease in the interface. The difference between the surface morphology of the synthesized TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal and the surface morphology of the TlInS2 single crystal is established, which consists in a decrease in the height and width of the roughness in TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]). Irradiation of a TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal with electrons with a fluence of [Formula: see text] electron/cm2 does not lead to a change in the height of the tubercle on its surface, and the average value of its width increases more than ten-fold. The identity of the peaks in the Raman spectra of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal before and after its irradiation with electrons with an energy of 2 MeV and upto a fluence of [Formula: see text] electron/cm2, along with the absence of a shift of the peaks, indicates the radiation resistance of the TlInS[Formula: see text]Se[Formula: see text] ([Formula: see text]) single crystal.

Effect of ring substituents on the fluorescence spectra of substituted diarylcarbenes

1988 ◽  
Vol 66 (3) ◽  
pp. 491-494 ◽  
Author(s):  
J. C. Scaiano ◽  
D. Weir
Keyword(s):  
Free Radical ◽  
Temperature Dependence ◽  
Fluorescence Spectra ◽  
Excellent Correlation ◽  
Emission Data ◽  
The Difference

The fluorescence spectra of a series of ring-substituted diarylcarbenes have been examined. The solution spectra are generally red shifted by 25–30 nm with respect to the band positions in matrices at 77 K. The difference is believed to reflect emission from non-relaxed conformations at 77 K. Both electron-withdrawing and -donating substituents lead to red shifts in the emission. These shifts are essentially additive, and the carbene emission data show an excellent correlation with free radical fluorescence data for the corresponding diarylmethyl radicals. The temperature dependence of excited carbene lifetimes have been examined for a few representative examples.

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