TWO STEP CURRENT INCREASES IN GLOW DISCHARGE DEVELOPMENT IN NEON FILLED DIODE AT 4 mbar

Abstract. The results are presented of investigating temporal and spatial development of electrical glow discharge in a neo

Study of Green Nanoparticles and Biocomplexes Based on Exopolysaccharide by Modern Fourier Transform Spectroscopy

The intention of this chapter is to contribute in clarification of nanoparticle synthesis and biocomplexes based on exopolysaccharide, green synthetic method development, their physico‐chemical characterization by modern spectroscopy, as well as testing of their antimicrobial activity. Silver nanoparticles of polysaccharide type have scientific interest, but practical importance too, because of their application in pharmaceutical and cosmetic product development due to proven antimicrobial and antioxidant activities. On the other hand, the biocomplexes based on exopolysaccharides are important in treatment of biometal deficiency in human and veterinary medicine, as well as in metal ion transporting in organism. Despite a number of studies of this kind of complexes, the investigations of effect of their structure to pharmaco‐biological activity are still interesting. It is important that question of interaction between reducing and stabilizing agents with metal ions is still opened. In this respect, the presented chapter offers further progress in the examination of silver nanoparticles and cobalt biocomplex synthesis with dextran oligosaccharides and its derivatives (such as dextran sulfate and carboxymethyl dextran). The complex structure, spectroscopic characterization, and the spectra‐structure correlation have been analyzed by different Fourier transform infrared (FTIR) spectroscopic techniques combined with energy‐dispersive X‐ray (EDX), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and surface plasmon resonance UV‐Vis methods

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

Supplementary data for article: Makarov, S. E.; Bodner, M.; Reineke, D.; Vujisić, L. V.; Todosijević, M. M.; Antić, D. Ž.; Vagalinski, B.; Lučić, L. R.; Mitić, B. M.; Mitov, P.; et al. Chemical Ecology of Cave-Dwelling Millipedes: Defensive Secretions of the Typhloiulini (Diplopoda, Julida, Julidae). Journal of Chemical Ecology 2017, 43 (4), 317–326. https://doi.org/10.1007/s10886-017-0832-1

Supplementary material for: [https://doi.org/10.1007/s10886-017-0832-1]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2450

TWO STEP CURRENT INCREASES IN GLOW DISCHARGE DEVELOPMENT IN NEON FILLED DIODE AT 4 mbar UDC 537.52; 533.9

Abstract. The results are presented of investigating temporal and spatial development of electrical glow discharge in a neon filled tube under 4mbar pressure. Linear increasing voltage (at 5 V/s increasing voltage rate) is applied to the gas diode. Time dependence of 585.2 nm line light emitted from negative glow is observed from various positions in the diode during formation of electrical discharge. The results show that the development of glow discharge starts in the gap, and propagates to the cathode and in the space around and behind the cathode. An unexpected two-step current rise is found. In the stationary regime, most of the emitted light occupied the cathode carrier rod. This indicates the position where the secondary electron emission is intensive. It corresponds to the second step in the current increase app. 3 ms after the breakdown has already taken place. It is assumed that this step originates from different surface characteristics of the rode material. The analysis of time dependencies of the current and light from the negative glow, from different positions in the gas diode, suggests that the observation of deexcitation processes in gas can be used for determination of early discharge formative processes, as well as processes that lead to the stationary regime in the gas diode tube

Bioactivity of Chamaecyparis lawsoniana (A. Murray) Parl. and Thuja plicata Donn ex D. Don essential oils on Lymantria dispar (Linnaeus, 1758) (Lepidoptera: Erebidae) larvae and Phytophthora de Bary 1876 root pathogens

We examined essential oils (EOs) of Chamaecyparis lawsoniana and Thuja plicata (Cupressaceae), their antifeedant activity on Lymanthria dispar larvae and their antimicrobial activity. Studies of EOs showed that these two conifer species differed both in content of terpene classes and the major compounds. Total monoterpenes strongly dominated in T. plicata (96.4%), while C. lawsoniana was rich in both mono- and sesquiterpenes (40.8% and 30.3%, respectively) as well as in diterpenes (19.1%). The most dominant compounds of C. lawsoniana EO were: limonene (16.7%), oplopanonyl acetate (14.5%), beyerene (10.1%), and 13-epi-dolabradiene (6.7%). The dominant compound of T. plicata EOs was α-thujone (76.9%), followed by relatively small amounts of β- thujone (5.3%), sabinene (4.5%) and terpinene-4-ol (3.2%). The difference in EO compositions of the conifers was reflected on Lymantria dispar larvae performance. Larvae fed on the leaf discs treated by C. lawsoniana EO had a slight phagostimulatory effect at lower concentration shown by higher relative rate of food consumption and relative growth rate than the larvae in the control group. Contrastingly, leaf discs treated with EO of T. plicata EO had an antifeedant effect and lower relative consumption rate (RCR) and relative growth rate RGR than the larvae in the control group. Both tested EOs influenced substantially the colony growth of the subjected Phytophthora plurivora and P. quercina. Namely, 100% inhibitory effect was recorded at concentration of 0.1% in the case of C. lawsoniana EO, whereas of T. plicata colonies did not grow at 0.5% concentration. The implications of these findings and possibility of using the tested EOs in further experiments in vitro and in vivo are discussed

FIGURES 12 – 13. Belbogosoma bloweri n. gen., n in On a new genus of endemic millipedes (Diplopoda: Chordeumatida: Anthroleucosomatidae) from the Balkan Peninsula

FIGURES 12 – 13. Belbogosoma bloweri n. gen., n. sp., holotype male from the Gornja Peċina Cave, village of Lenovac, Mt. TupiŽnica, Eastern Serbia; 12 — posterior gonopods, oral view; 13 — posterior gonopods, caudal view