First record of the Northern brown shrimp, Farfantepenaeus aztecus (Ives, 1891) (Crustacea: Decapoda: Penaeidae) in the South Adriatic Sea, Montenegro

A single adult female specimen of the Northern brown shrimp, Farfantepenaeus aztecus, a species native to the western Atlantic coasts, was caught in Boka kotorska bay (southern Adriatic Sea) on 19 September 2013. This is the first record of this alien species in the Adriatic Sea

Molekulsko-orbitalno proučavanje oksidacije fenola u hinole i epoksihinole

The MO study showed that the radical oxidation of phenols into quinols occurs readily. Further radical oxidation (in the m-CPBA/(BzO)(2)/hv system) of quinols occurs through appropriate biradical species with an activation energy of 79.5 kJ/mol yielding syn-epoxyquinols. The stereochemical outcome presented in this study is in full agreement with the experimental results.Molekulsko-orbitalnim proučavanjem potvrđeno je da lako dolazi do radikalske oksidacije fenola u odgovarajuće hinole. Daljom oksidacijom sistemom m-CPBA/(BzO)2/hν hinoli se preko biradikalskih reakcionih vrsta oksiduju u odgovarajuće epoksihinole. Izračunato je da aktivaciona energija ove reakcije iznosi 79.5 kJ/mol. Stereohemijske posledice naših izračunavanja su u potpunom skladu sa eksperimentalnim rezultatima

ANNs in Bias Dependant Small-Signal and Noise Modeling of Microwave FETs

In this paper an efficient procedure for determination of small-signal and noise behavior of microwave transistors for various bias conditions is proposed. An empirical transistor noise model based on an equivalent circuit (improvement of Pospieszalski’s noise model) is considered. Since it is necessary to extract values of the model equivalent circuit for each bias point (which requires the measured data acquiring and repeated time consuming extraction procedures), it is proposed to use an artificial neural network to model the bias dependence of the equivalent circuit parameters. In that way, it is necessary to acquire the measured data and extract the equivalent circuit parameters only for several operating biases used for the network training. Once the neural network is trained, the device small-signal scattering and noise parameters are easily obtained for an arbitrary bias point from the device operating range without changes in the model. The proposed modeling approach is exemplified by modeling of a specific MESFET device in a packaged form

Occupational exposure to benzene and haematological changes

U ljeto 1984. godine radnice u tvornici "INA-OKI Drnišplast" učestalo su se tužile na glavobolju, mršavljenje i poremećene menstruacijske cikluse. Budući da su inženjeri u tvornici pretpostavili da je tome uzrok promijenjen sastav boja i ljepila koje su se te godine upotrebljavale bez deklaracije, pozvan je Institut za sigurnost iz Zagreba da izmjeri koncentracije organskih otapala u radnoj atmosferi. Analize su potvrdile da su koncentracije benzena i do pet puta više od maksimalno dopuštenih, toluena do tri puta i cikloheksana i do deset puta. Pogon je zatvoren, radni proces je izmijenjen (boje nisu upotrebljavane, za lijepljenje je rabljeno ljepilo koje ne sadržava benzen, primijenjena je odgovarajuća ventilacija) i sve radnice podvrgnute su liječenju. Nakon tri mjeseca pogon je ponovno počeo s radom. Kontrolni pregled obavljen 1989. pokazao je znakove subjektivnog i objektivnog oporavka svih dvadeset radnica. Svi nalazi krvi bili su u normalnim granicama i sve radnice nastavile su raditi, osim jedne, koju je 1988. godine Invalidska komisija uputila u mirovinu zbog profesionalne bolesti - otrovanja benzenom. Ovaj prikaz događaja potvrđuje da je pri radu s benzenom važno dosljedno pridržavanje uputa iz Pravilnika o utvrđivanju radne sposobnosti za obavljanje poslova s posebnim uvjetima rada i Zakona o zaštiti na radu.In the summer of 1984 workers in the "INA-OKI Drnišplast" factory frequently complained about headaches, weight loss and irregular menstrual cycles. According to the factory engineers that might have been due to an altered composition of the paints and glues that were used in the manufacturing process that year. Those had been found to lack specifications of chemical composition. Experts from the Institute for the Safety at Work from Zagreb were called in to perform measurements of organic solvents content in the workroom air. Benzene concentrations were found to be up to five times higher than the maximum permissible levels, those of toluene up to three; times and of cyiclohexane up to ten times higher. The polluted part of the factory was closed down, changes were introduced into the working process (use of paints was stopped, only glues without benzene content were allowed and proper ventilation was installed) and all the workers, twenty in all, received medical treatment. After three months the working process was resumed. In 1989 all the twenty workers underwent a control medical examination. All showed signs of recovery, both objective and subjective. Their blood tests values were within normal range. All the workers continued working, save one who retired in 1988 upon recommendation of a disability commission. The cause of disablement was occupational disease - benzene poisoning. On the basis of this experience emphasis is placed on the importance, in working with benzene, of complying with the legislation on working capacity assessment for jobs requiring special working conditions and with the Safety at work act

Methoden der Gewebskulturen in den stomatologischen Untersuchungen

Autori prikazuju metode ispitivanja kultivisanjem fibroblasta i zubnih začetaka miša u sistemu in vitro. Rezultati dobijeni kultivisanjem zubnih začetaka miša u raznim fazama embriogeneze pokazuju da ovaj metod ispitivanja (in vitro) pruža izvesne prednosti u odnosu na sistem in vivo.LI in vivo sistemu prömene nastale tokom života, u toku histološke obrade uzetog materijala, kao i intraoperativno, teško je razlikovati od onih, koje nastaju kao posledica agensa koji se ispituje, što je svedeno na minimum u in vitro sistemu. Pored ovog, ispitivanja u in vitro sistemu vremenski su kraća i ekonomičnija, mogu obuhvatiti veći broj uzoraka, što je uslov za statističku obradu rezultata.The authors report \u27the methods which have been used during the cultivation of fibroblast and tooth embryo in the system in vitro. The results of experiments in the cultivation of the mice tooth embryo, taken intrauterine on the 20—21st day of embryonal development, have indicated that investigation in vitro has some advantages in regard to the system in vivo. These advantages are as follows: 1. The changes observed during the experiment in vivo either those produced during life time or those created by iatrogenic influence and caused in the technical procedures for hystologica! examination, are reduced to the minimum in the system in vitro. 2. The experiments in the system in vitro are shorter in terms of time and more economical. Therefore, a great number of cultures can be provided and the results of the experiment better presented with statistics.Die Autoren beschreiben Untersuchungsmethoden der Gewebe mittels Fibroblasten und Zahnkeimen der Maus in vitro Resultate die in verschiedenen Phasen der Embryogenese erhalten wurden, beweisen dass die Untersuchungsmethoden in vitro gewisse Vorteile im Vergleich mit Untersuchungen in vivo bieten. Veränderungen die im Verlaufe des Lebens, im Verlaufe der histologischen Bearbeitung des Materials eintreten, als auch intraoperative Veränderungen, sind nur schwer von jenen welche als Folge des untersuchten Agens stattfinden, zu unterscheiden, was in vitro auf ein Minimum reduziert ist. Untersuchungen in vitro sind zeitlich kürzer und ekonomischer, sie können eine grössere Anzahl von Müstern umfassen, was als Bedingung für die statistische Bearbeitung der Resultate anzusehen ist

Tunable Charge Density Wave Transport in a Current-Effect Transistor

The collective charge density wave (CDW) conduction is modulated by a transverse single-particle current in a transistor-like device. Nonequilibrium conditions in this geometry lead to an exponential reduction of the depinning threshold, allowing the CDWs to slide for much lower bias fields. The results are in excellent agreement with a recently proposed dynamical model in which ''wrinkles'' in the CDW wavefronts are ''ironed'' by the transverse current. The experiment might have important implications for other driven periodic media, such as moving vortex lattices or ''striped phases'' in high-Tc superconductors.Comment: 4 pages, 4 figure

Fermiology and superconductivity of topological surface states in PdTe2

We gratefully acknowledge support from the Leverhulme Trust, the Engineering and Physical Sciences Research Council, UK (Grant Nos. EP/M023427/1 and EP/I031014/1), the Royal Society. JC, MJN, LB, VS, and JMR acknowledge EPSRC for PhD studentship support through grant Nos. EP/K503162/1, EP/G03673X/1, EP/L505079/1, and EP/L015110/1.We study the low-energy surface electronic structure of the transition-metal dichalcogenide superconductor PdTe2 by spin- and angle-resolved photoemission, scanning tunneling microscopy, and density-functional theory-based supercell calculations. Comparing PdTe2 with its sister compound PtSe2, we demonstrate how enhanced interlayer hopping in the Te-based material drives a band inversion within the antibonding p -orbital manifold well above the Fermi level. We show how this mediates spin-polarized topological surface states which form rich multivalley Fermi surfaces with complex spin textures. Scanning tunneling spectroscopy reveals type-II superconductivity at the surface, and moreover shows no evidence for an unconventional component of its superconducting order parameter, despite the presence of topological surface states.PostprintPeer reviewe

Kinetičko modelovanje sorpcije teških metala kopolimerom sa osnovom vinil piridina

Commercial macroporous poly(4-vinylpyridine-co-divinylbenzene) [P4VPD], known as Reillex-425, was characterized by mercury porosimetry, nitrogen physisorption, Fourier transformed infrared (FTIR) spectroscopy and elemental analysis. Sorption rates of P4VPD for Cu(II), Co(II) and Cr(VI) ions were determined in static non-competitive experiments, at room temperature (298 K). Rapid sorption was observed, especially for Co(II), with half time, t1/2, of 1.5 min and high experimental maximal capacity, Qmax, of 3.08 mmol g-1. Four kinetic models (pseudo-first and pseudo-second order model, intraparticle diffusion and Boyd model) were used for analyzing metal sorption by P4VPD. Metal ions sorption is well represented by the pseudo-second-order model, with definite influence of pore and film diffusion on sorption rates.Komercijalni makropozni poli(4-vinilpiridin-co-divinilbenzen) [P4VPD], Reillex- 425, bez dodatne funkcionalizacije korišćen je za ispitivanje mogućnosti sorpcije teških metala iz vodenih rastvora. Na taj način su izbegnuti neki problemi do kojih može doći prilikom uvođenja funkcionalnih grupa selektivnih za određene jone metala u polimerne sorbente, kao što su nepoželjne sporedne reakcije i promena porozne strukture. P4VPD je okarakterisan živinom porozimetrijom, određivanjem adsorpciono-desorpcionih niskotemperaturnih izotermi azota, infracrvenom spektroskopijom (FTIR) i elementalnom analizom. U statičkim eksperimentima su određene brzine sorpcije Cu(II), Co(II) i Cr(VI) jona pomoću P4VPD pri nekompetitivnim uslovima i pri sobnoj temperaturi (298 K). Zapažena je brza sorpcija ispitivanih jona, naročito u slučaju Co(II), pri čemu su zapažene vrednosti poluvremena sorpcije, t1/2, od 1,5 min i visoka vrednost maksimalnog kapaciteta sorpcije, Qmax, od 3,08 mmol g-1 (181 mg g-1). Prilikom analiziranja sorpcije ispitivanih metala pomoću P4VPD korišćena su četiri kinetička modela (model pseudo-prvog i pseudo-drugog reda, model difuzije unutar čestica i Bojdov model). Pokazalo se da sorpciju jona metala najbolje opisuje model pseudo-drugog reda, pošto je za ovaj model dobijeno odlično slaganje eksperimentalnih i teorijskih vrednosti kapaciteta sorpcije, kao i vrednosti R2 ≥ 0,99. Analiza eksperimentalnih rezultata pomoću modela difuzije unutar čestica pokazala je da difuzija kroz pore nije jedini stupanj koji određuje brzinu sorpcije i ukazala na delimičan uticaj graničnog sloja na sorpciju teških metala pomoću poroznog kopolimera

New Mediterranean Biodiversity Records (April, 2014)

According to reports, the following 16 species have extended their distribution to other Mediterranean areas or have made a new appearance in other regions. The first category includes the following organisms: The rare and common Indo-Pacific seaweed Codium arabicum (Lebanese coasts), the acari Thalassarachna affinis (Marmara Sea), and the non-indigenous nudibranch Flabellina rubrolineata, which has also been found in many other areas of the Aegean Sea. In addition, the rare sea slug Thecacera pennigera (Piccolo of Taranto), the fangtooth moray Enchelycore anatina (National Marine Park of Zakynthos, Ionian Sea), the carangid Seriola fasciata (Gulf of Antalya), Lagocephalus sceleratus (SE. Ionian Sea), the reticulated leatherjacket Stephanolepis diaspros (Slovenia, N. Adriatic Sea), the marbled stingray, Dasyatis marmorata (NE Levantine), the starry smooth-hound Mustelus asterias (Iskenderun Bay, NE Mediterranean), the cephalopod Ommastrephes bartramii (Ionian Sea) have also been reported. The Atlantic crab Dyspanopeus sayi has expanded to many Italian areas and the blue crab Callinectes sapidus to a lake in N. Greece and in the S. Adriatic Sea. Finally, Farfantepenaeus aztecus has been found in the Ionian Sea, thus showing its wide expansion in the Mediterranean. The larval stages of Faccionella oxyrhyncha have been found, after many years, in the Aegean Sea and the first report of an existence on intersexual acari Litarachna duboscqi in Split(Adriatic Sea) was reported

Pseudo-single crystal electrochemistry on polycrystalline electrodes : visualizing activity at grains and grain boundaries on platinum for the Fe2+/Fe3+ redox reaction

The influence of electrode surface structure on electrochemical reaction rates and mechanisms is a major theme in electrochemical research, especially as electrodes with inherent structural heterogeneities are used ubiquitously. Yet, probing local electrochemistry and surface structure at complex surfaces is challenging. In this paper, high spatial resolution scanning electrochemical cell microscopy (SECCM) complemented with electron backscatter diffraction (EBSD) is demonstrated as a means of performing ‘pseudo-single-crystal’ electrochemical measurements at individual grains of a polycrystalline platinum electrode, while also allowing grain boundaries to be probed. Using the Fe2+/3+ couple as an illustrative case, a strong correlation is found between local surface structure and electrochemical activity. Variations in electrochemical activity for individual high index grains, visualized in a weakly adsorbing perchlorate medium, show that there is higher activity on grains with a significant (101) orientation contribution, compared to those with (001) and (111) contribution, consistent with findings on single-crystal electrodes. Interestingly, for Fe2+ oxidation in a sulfate medium a different pattern of activity emerges. Here, SECCM reveals only minor variations in activity between individual grains, again consistent with single-crystal studies, with a greatly enhanced activity at grain boundaries. This suggests that these sites may contribute significantly to the overall electrochemical behavior measured on the macroscale