Development of photoacoustic measurement system for thermal characterisation of thin samples

Настанак звучног таласа након осветљавања узорка модулисаним светлосним снопом назива се фотоакустички (ФА) ефекат. Теоријска истраживања предвиђају да је уз помоћ мерних техника заснованих на ФА ефекту могуће извршити одређивање карактеристика танких узорака. ФА технике нису инвазивне и због тога изазивају интересовање у разним областима науке, медицине и технике. У зависности од карактеристика које се желе проучавати, примењују се различите технике засноване на ФА ефекту. У фокусу предложеног истраживања је примена фреквенцијске ФА технике за термичку карактеризацију, док ће споредни правац истраживања разматрати могућности повезивања фреквенцијске ФА технике са ФА спектроскопијом ради симултане оптичке и термичке карактеризације. Предмет истраживања је развој ФА мерног система (ФАМС) за одређивање термичких параметара танких узорака, и то термичке дифузивности, термичке проводности и коефицијента термичког ширења. Систем се састоји од побудног дела, ФА ћелије и детекционог дела. Побудни део система чине извор светлости и модулатор светлосног снопа. Модулисани светлосни сноп погађа узорак у коме се апсорбује део светлосне енергије, што за последицу има формирање акустичког сигнала фреквенције једнаке фреквенцији модулације светлосног снопа. Генерисани акустички сигнал се детектује микрофоном, док се део светлости који се рефлектује од узорка детектује фотодетектором, па детекциони део система чине микрофон са претпојачавачем, фотодетектор, појачавачи детектованих сигнала и систем за аквизицију. У оквиру система за аквизицију се налазе аквизициона картица, lock-in детектор и рачунар. ФА ћелијом се назива затворени простор у коме се простире акустички сигнал генерисан ФА ефектом. Мада ФА ћелија може бити изведена као комора у коју се постављају узорак, микрофон и фотодетектор, чешће се узорак причвршћује директно за микрофон, тако да простор између узорка и микрофона представља ФА ћелију...The formation of sound waves after exposition of a sample to a modulated light beam is called the photoacoustic (PA) effect. Theoretical researches predict that it is possible to determine characteristics of thin samples with the help of measurement techiques based on the PA effect. PA techniques are not invasive and for this reason cause interest in many different areas of science, medicine and technique. Depending on the characteristics to be studied, different techniques are applied based on the PA effect. In the focus of the suggested research is the application of the PA frequency technique for thermal catheterization, while the secondary direction of the research will consider possibilities of connecting the frequency PA technique with the PA spectroscopy aimed at the simultaneous optical and thermal characterization. The subject of research is the development of the PA measurement system for determination of thermal parameters of thin samples, namely thermal diffusivity, thermal conductivity and linear expansion coefficient. The system consists of an excitation part, a PA cell and a detection part. The excitation part of the system consists of a light source and a modulator of the light beam. The modulated light beam affects the sample, which absorbs a part of the light energy, and due to the PA effect, the created acoustic signal has the same frequency as the light-beam modulations. Generated acoustic signal is detected by a microphone, whereas the part of light reflected from the sample is detected by a photodetector, so the detection part of the system consists of the microphone with a preamplifier, photodetector, amplifiers of the detected signals and an acquisition system. The acquisition system includes an acquisition card, a lock-in detector and a computer. The PA cell is a closed space in which an acoustic signal is generated by the PA effect. Although a PA cell can be a chamber in which the sample, microphone and photodetector are placed, more often the sample is attached directly to the microphone, so that the space between the sample and the microphone represents a PA cell..

Volatile Constituents of Different Plant Parts and Populations of Malabaila aurea Boiss. from Montenegro

The volatile constituents of different plant parts and populations of Malabaila aurea Boiss. from Montenegro were obtained by simultaneous distillation-extraction and analyzed by GC-FID and GC-MS. A total of 12 samples were examined and 45 compounds were identified. The volatile content of different M. aurea populations was very similar, while the volatile fractions obtained from different plant parts showed significant qualitative and quantitative differences. The most abundant compounds found in stems & leaves were apiole (51.0-56.3%), myristicin (16.3-25.4%), and falcarinol (4.1-10.7%). The roots showed the same major components, but with different relative abundances: 30.9-49.1% of apiole, 12.9-34.7% of falcarinol, and 9.9-31.1% of myristicin. The volatile constituents of fruits & flowers were remarkably different, containing up to 71.2-80.5% octyl butyrate, 11.4-18.0% octanol, and 2.7-6.8% octyl hexanoate. The results were discussed as possible indication of relatedness of Malabaila aurea and Pastinaca sativa (parsnip)

Trophic chain Yersinia pseudotuberculosis

This paper tries to reproduce two types of trophic chains on the example of an aquatic ecosystem model, with the participation of planktonic and benthic organisms: "yersinia - infusoria - daphnia - fish" and "yersinia - insect larvae - fish". The concentration of Yersinia pseudotuberculosis during primary infection (infusoria culture medium) was 109/ml. In the first hours after infection, the concentration of bacteria in the infusoria decreased (105cfu/mass ). In daphnia, which consumed infected infusoria, the concentration of Yersinia pseudotuberculosis decreases in the first 3-5 days (from 105 to 103 cfu/10 individuals), then the reproduction of Yersinia pseudotuberculosis in daphnia continues, and on the 11th day it reaches 107 cfu/10 individuals. The concentration of Yersinia pseudotuberculosis in the intestines of fish fed infected daphnia (107cfu/10 individuals) is continuously decreasing: 105 cfu (after 24 hours) and 102-101 cfu/individuals (after 15-30 days)

Uticaj fitohormona na vegetativno razmnožavanje različitih formi panonskog timijana (Thymus pannonicus All.)

The paper examined the impact of the application of three different phytohormones (INCIT 2, INCIT 5 and INCIT 8, all based on a-Naphthalene Acetic Acid (NAA)), with the cuttings of two forms of Pannonian thyme (the L-16 form, with hairy leaves, and the L-9 form, with hairless leaves), established during two periods (March and May), on the percentage of the rooted cuttings and the morphological properties of the seedlings. As the control, the variant without the application of the phytohormones was taken. The research was conducted in the period from 2019 to 2020, in a plastic greenhouse, using the plant collection of the Institute for Medicinal Plants Research "Dr Josif Pančić", which is located in Pančevo city, Serbia (44°52'20"N; 20°42'06"E; 74 m.a.s.l.). For this research was used the Pannonian thyme species (Thymus pannonicus All.) from the Lamiaceae family, which is grown and produced at the Institute. Plant establishment was carried out in four repetitions with 33 cuttings per each variant. Standard measures of care were used during the period of production of Pannonian thyme. The measurement was performed after 60 days from the date of conducted the experiment. The following parameters were measured: the percentage of rooted cuttings (%), the mass of the rooted plantlings (g), the mass of roots (g), the length of rooting (cm) and the number of root hairs of the formed rootings. The measuring was done using a ruler, millimetre paper and an analytical balance. Given the results achieved, INCIT 2 proved to be the most suitable phytohormone for the rooting of Pannonic thyme cuttings, with the average percentage of rooted cuttings of 61.3%. The lowest rooting percentage was recorded in the control variant, only 29.4%. Satisfactory rooting was found in the cuttings treated with INCIT 8 (57.6%). The L-16 form cuttings showed a higher rooting rate, an average of 53.8%, whereas the L-9 form cuttings had a lower average percentage of rooted cuttings (45.0%) for both plant establishment periods. Greater success and quality in the rooting of cuttings was recorded in the second (May) period of plant establishment, averaging 58.1%, which was higher by 17.4% than the percentage of rooted cuttings in the first establishment period (40.7%). It is important to note that the rooting of the L-9 form was significantly higher in the second establishment period (58.1%) than that in the first establishment period (31.9%).U radu je ispitivan uticaj primene tri fitohormona na bazi a-naftil-sirćetne kiseline (NAA) (INCIT 2, INCIT 5 i INCIT 8), na procenat ožiljenih reznica i morfološke osobine sadnica dveju formi panonskog timijana (L-16, forma sa dlakavim listovima i L-9 forma sa glatkim listovima), zasnovanih u dva termina (u martu i maju). Varijanta bez primene fitohormona uzeta je kao kontrolna. Istraživanja su realizovana u periodu od 2019. do 2020. godine, u plasteniku, na lokaciji biljne kolekcije Instituta za proučavanje lekovitog bilja "Dr Josif Pančić" u Pančevu (44°52'20"N; 20°42'06"E; 74 m.n.v.). Za ova istraživanja korišćen je panonski timijan (Thymus pannonicus All.) iz familije Lamiaceae, koja se gaji i umnožava u Institutu. Ogled je zasnovan u četiri ponavljanja sa 33 reznice po svakoj varijanti. Tokom perioda proizvodnje reznica panonskog timijana korišćene su standardne mere nege. Merenje je obavljeno 60 dana nakon postavljanja ogleda. Meren je procenat ožiljenih reznica (%), masa ožiljene biljčice (g), masa korenčića (g), dužina korenčića (cm) i broj žilica formiranih korenčića. Merenje je obavljeno pomoću lenjira, milimetarske hartije i precizne analitičke vage. Na osnovu ostvarenih rezultata, kao najpogodniji fitohormon za ožiljavanje reznica panonskog timijana pokazao se INCIT 2, kod koga je prosečan procenat ožiljenih reznica bio 61,3%. Najmanji procenat ožiljavanja zabeležen je pri kontrolnoj varijanti, samo 29,4%. Zadovoljavajuću ožiljenost pokazale su reznice tretirane preparatom INCIT 8 (57,6%). Reznice forme L-16 pokazale su veću ožiljenost, u proseku 53,8%, dok su reznice forme L-9 imale manji procenat ožiljenih reznica (45,0%) u proseku za oba termina zasnivanja. Veća uspešnost i kvalitet ožiljavanja reznica evidentirana je u drugom (majskom) terminu zasnivanja (58,1%), što je za 17,4% više u odnosu na procenat ožiljenih reznica u prvom terminu zasnivanja (40,7%). Bitno je istaći da je ožiljenost forme L-9 bila značajno veća u drugom terminu zasnivanja (58,1%) u odnosu na prvi termin zasnivanja (31,9%)

The impact of agroecological factors on the content of mineral matters in maize

Mineralne materije su neophodne biljkama za rast i razvoj, kao i za normalno funkcionisanje ljudskog i organizma životinja. Mineralne materije u lance ishrane ulaze preko biljaka, pa je poznavanje i proučavanje mineralnog sastava biljaka izuzetno značajno. Ispitivanje sadržaja mineralnih materija u zrnu kukuruza, u zavisnosti od rastuće količine azota đubriva, obavljeno je u dvogodišnjem periodu, na lokalitetu Zemun Polje, u klimatskim uslovima Istočnog Srema. Na ogledima je primenjena standardna agrotehnika. Hemijski sastav ploda kukuruza, tokom dve godine istraživanja, određivan je u fazi fiziološke zrelosti zrna kukuruza. Rezultati istraživanja pokazuju da je, u proseku za ispitivane faktore, sadržaj mineralnih materija u zrnu kukuruza iznosio 1,87%. U prvoj godini istraživanja, utvrđen je veći sadržaj pepela u zrnu za 0,23% u poređenju s drugom godinom. Primenjene količine azota značajno i veoma značajno su uticale na sadržaj mineralnih materija u zrnu kukuruza.Mineral matters are necessary for the growth and development of plants as well as for normal functioning of human and animal organisms. Mineral matters enter the food chains through the plants making the knowledge and study of the mineral content of plants very remarkable. The study of the content of mineral matters in maize grain, depending on the growing quantities of nitrogen fertilizer, has been conducted during a two-year period on the locality of Zemun Polje, in climate conditions of the Eastern Srem. In these experiments, a standard agrotechnique is applied. The chemical contents of the maize yield during the two-year period of the experiment is determined in a phase of the phyisiological ripeness of maize grain. Our research results show that, in the average for the examined factors, the content of mineral matters in maize grain was 1.87%. It is determined that the content of ash in grain was for 0.23% higher in the first year of the experiment than in the second one. The applied quantities of nitrogen had a significant and a very significant impact on the content of mineral matters in maize grain.Radovi sa 33. Savetovanja agronoma, veterinara, tehnologa i agroekonomista, Padinska Skela, 2019

Volatile Constituents of Different Plant Parts and Populations of Malabaila aurea Boiss. from Montenegro

The volatile constituents of different plant parts and populations of Malabaila aurea Boiss. from Montenegro were obtained by simultaneous distillation-extraction and analyzed by GC-FID and GC-MS. A total of 12 samples were examined and 45 compounds were identified. The volatile content of different M. aurea populations was very similar, while the volatile fractions obtained from different plant parts showed significant qualitative and quantitative differences. The most abundant compounds found in stems & leaves were apiole (51.0-56.3%), myristicin (16.3-25.4%), and falcarinol (4.1-10.7%). The roots showed the same major components, but with different relative abundances: 30.9-49.1% of apiole, 12.9-34.7% of falcarinol, and 9.9-31.1% of myristicin. The volatile constituents of fruits & flowers were remarkably different, containing up to 71.2-80.5% octyl butyrate, 11.4-18.0% octanol, and 2.7-6.8% octyl hexanoate. The results were discussed as possible indication of relatedness of Malabaila aurea and Pastinaca sativa (parsnip)

Cuticular chemoprofile of the fruit fly drosophila subobscura (diptera, drosophilidae)

In insects, cuticular hydrocarbon (CHC) profile is involved in many important biological functions and may vary in different conditions. Among fruit fly species, Drosophila subobscura is one of the most frequently used in genetic, ecological and evolutionary research, because of its rich chromosomal polymorphism, specific behavioral repertoires and habitat preferences. In this work, we identified and quantified cuticular chemoprofile of D. subobscura. Using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS), 25 chemical compounds were found in males and 23 compounds were found in females. Further, ANOVA confirmed significant sexual dimorphism in cuticular chemoprofile amounts. Knowledge of cuticular chemistry could contribute to further research in D. subobscura, starting from behavioral, up to ecological, since this species is recognized as an important model system for the study and monitoring of global climate changes

Cuticular chemoprofile of the fruit fly Drosophila Subobscura (Diptera, drosophilidae)

In insects, cuticular hydrocarbon (CHC) profile is involved in many important biological functions and may vary in different conditions. Among fruit fly species, Drosophila subobscura is one of the most frequently used in genetic, ecological and evolutionary research, because of its rich chromosomal polymorphism, specific behavioral repertoires and habitat preferences. In this work, we identified and quantified cuticular chemoprofile of D. subobscura. Using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS), 25 chemical compounds were found in males and 23 compounds were found in females. Further, ANOVA confirmed significant sexual dimorphism in cuticular chemoprofile amounts. Knowledge of cuticular chemistry could contribute to further research in D. subobscura, starting from behavioral, up to ecological, since this species is recognized as an important model system for the study and monitoring of global climate changes. © 2018, Pakistan Agricultural Scientists Forum. All rights reserved

Chemical Ecology of Cave-Dwelling Millipedes: Defensive Secretions of the Typhloiulini (Diplopoda, Julida, Julidae)

Cave animals live under highly constant ecological conditions and in permanent darkness, and many evolutionary adaptations of cave-dwellers have been triggered by their specific environment. A similar "cave effect" leading to pronounced chemical interactions under such conditions may be assumed, but the chemoecology of troglobionts is mostly unknown. We investigated the defensive chemistry of a largely cave-dwelling julid group, the controversial tribe "Typhloiulini", and we included some cave-dwelling and some endogean representatives. While chemical defense in juliform diplopods is known to be highly uniform, and mainly based on methyl- and methoxy-substituted benzoquinones, the defensive secretions of typhloiulines contained ethyl-benzoquinones and related compounds. Interestingly, ethyl-benzoquinones were found in some, but not all cave-dwelling typhloiulines, and some non-cave dwellers also contained these compounds. On the other hand, ethyl-benzoquinones were not detected in troglobiont nor in endogean typhloiuline outgroups. In order to explain the taxonomic pattern of ethyl-benzoquinone occurrence, and to unravel whether a cave-effect triggered ethyl-benzoquinone evolution, we classed the "Typhloiulini" investigated here within a phylogenetic framework of julid taxa, and traced the evolutionary history of ethyl-benzoquinones in typhloiulines in relation to cave-dwelling. The results indicated a cave-independent evolution of ethyl-substituted benzoquinones, indicating the absence of a "cave effect" on the secretions of troglobiont Typhloiulini. Ethyl-benzoquinones probably evolved early in an epi- or endogean ancestor of a clade including several, but not all Typhloiulus (basically comprising a taxonomic entity known as "Typhloiulus sensu stricto") and Serboiulus. Ethyl-benzoquinones are proposed as novel and valuable chemical characters for julid systematics.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3085

Cuticular chemoprofile of the fruit fly drosophila subobscura (diptera, drosophilidae)

In insects, cuticular hydrocarbon (CHC) profile is involved in many important biological functions and may vary in different conditions. Among fruit fly species, Drosophila subobscura is one of the most frequently used in genetic, ecological and evolutionary research, because of its rich chromosomal polymorphism, specific behavioral repertoires and habitat preferences. In this work, we identified and quantified cuticular chemoprofile of D. subobscura. Using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS), 25 chemical compounds were found in males and 23 compounds were found in females. Further, ANOVA confirmed significant sexual dimorphism in cuticular chemoprofile amounts. Knowledge of cuticular chemistry could contribute to further research in D. subobscura, starting from behavioral, up to ecological, since this species is recognized as an important model system for the study and monitoring of global climate changes