ELECTRONIC SPECTROSCOPY OF CORONENE AND BENZOPERYLENE INSIDE HELIUM NANODROPLETS

Author Institution: Department of Chemistry, Princeton University; Department of Chemistry, University of VirginiaHelium Nanodroplet Isolation Spectroscopy (HENDI) is a hybrid technique combining the advantages of molecular beams and matrix isolation. We have taken $S_0 \rightarrow S_1$ spectra of Coronene and Benzoperylene inside helium clusters via the depletion method. Coronene spectrum is better resolved than the previously reported jet spectra and it is composed of sharp lines with about 0.5 cm$^{-1}$ full width. Although Benzoperylene lines are not as sharp, it is the only high resolution spectrum of this molecule to our knowledge. The van der Waals complexes of these molecules with Argon and Oxygen are also studied. The zero phonon line splittings for $S_0 \rightarrow S_1$ transitions in perylene, benzoperylene and coronene will be discussed

HIGH RESOLUTION SPECTROSCOPY OF ACETYLENE-FURAN IN HE NANO-DROPLETS}

[2]E. Sanchez-Garcya, A. Mardyukov, A. Tekin, R. Crespo-Otero, L.A. Montero, W. Sander, G. Jansen, submittedthis work was supported by FOR 618 of the German Science FoundationAuthor Institution: Department of Physical Chemistry II; Ruhr-University Bochum, Universitatsstr. 150, D-44780Acetylene-furan is an interesting benchmark system for the evaluation of hydrogen bonds. Since acetylene is the smallest molecule containing two hydrogens and a $\pi$-system it is interesting to study the influence of a C-H \"{}lone-pair\"{ } hydrogen-bond and a CH-$\pi$ or even a $\pi$-$\pi$ interaction. The global and local minimum structures have been predicted in a recent study}. For the experiment the molecules have been embedded in superfluid helium nanodroplets. The radiation source was a singly resonant OPO with an output power of up to 2.7 W and a resolution of up to $4 \times10^{-5}$~cm$^{-1}$. Helium clusters, which have a temperature of 0.37 K are doped with acetylene (pick-up pressure $1.3 \times 10^{-5}$ mbar) and furan (pick-up pressure $0.9 \times 10^{-5}$ mbar) and are then excited with the OPO-radiation. A mass-spectrometer is used to detect the depletion of the cluster beam. With this setup measurements were carried out in the region of the asymmetric stretch vibration of the acetylene. Between 3256 cm$^{-1}$ and 3280 cm$^{-1}$ five acetylene-furan cluster peaks could be detected. Two of these could be assigned to the acetylene-furan dimer. We will present a detailed analysis of the data

SOLVATION OF HCl, AGGREGATION OF H2_2O, HCl AND THEIR DEUTERATED ISOTOPES IN SUPERFLUID He DROPLETS}

this work was supported by FOR 618 of the German Science FoundationAuthor Institution: Department of Physical Chemistry II; Ruhr-University Bochum, Universitatsstr. 150, D-44780We investigate aggregates of HCl, H$_2$O and their deuterated isotopes embedded in superfluid helium using a helium nanodroplet spectrometer combined with a cw infrared OPO set up with an output power of up to 2.7 W and a resolution of better than 0.001 cm$^{-1}$. Depletion spectra of the super cooled aggregates (0.37 K) were recorded between 2650 cm$^{-1}$ and 2720 cm$^{-1}$. We were able to assign the HCl stretch vibration of the HCl-H$_2$O complex. We also observed spectral features of (HCl)$_m$(H$_2$O)$_n$ aggregates and isotopes in the region of the H$_3$O$^+$ stretch vibration. The question of how many H$_2$O molecules are needed to solvate HCl will be addressed

Formation and distribution of ZnO nanoparticles and its effect on E. coli in the presence of sepiolite and silica within the chitosan matrix via sonochemistry

In this study, a new bio-nanocomposite was prepared and characterized with a focus on the formation of hexagonal ZnO and orthorhombic zinc silicate (Zn2SiO3(OH)(2)) phases under ultrasonic irradiation. Chitosan/sepiolite/ZnO and chitosan/silica/ZnO bio-nanocomposites were synthesized using a simple solution method in which extreme physical and chemical conditions created by cavitation within the chitosan solution allowed for the transformation of aqueous Zn(OH)(2) to crystallized ZnO and Zn2SiO3(OF)(2) in room temperature. Both the loading of sepiolite and silica with the zinc precursor significantly influenced the morphology and crystalline structure of the product, however, different zinc compounds were observed. Sepiolite was exfoliated, resulting in a fine, even colloidal solution through ultrasonic dispersion. Exfoliation of sepiolite nanofibers led to the homogeneous dispersion of Zinc in the form of Zn (OH)(2) in chitosan matrix. When the same procedure was conducted using the silica component, a formation of ZnO and Zn2SiO3(OH)(2) was observed, components that were not observed when the procedure was conducted using sepiolite. The average crystalline size of ZnO was calculated as 36 nm for ZnO. In addition, the quantities of crystalline and the ZnO phase volume was determined as 15%. Through zone of inhibition, the silica nanocomposite was discovered to have antibacterial activity. In contrast, the sepiolite compound did not exhibit these properties. We thus hypothesize that HO center dot radicals, formed during ultrasonic irradiation trigger the formation of a silicate ion (SiO32-) and formation of ZnO and Zn2SiO3(OH)(2) species in chitosan/silica/ZnO bio-nanocomposite, which causes to exhibit these antibacterial properties against Gram-negative E. coli. Chemical characterization and dispersion of the structure of the ZnO and Zn2SiO3(OH)(2) phases were done using X-ray diffraction (XRD) and scanning electron microscopy techniques (SEM) with EDAX and X-ray photoelectron spectroscopy (XPS). (C) 2016 Elsevier B.V. All rights reserved

Agriculture as the opportunity for sustainable development of Slovene rural areas

Vloga kmetijstva na podeželju se je bistveno spremenila, celo povečala, saj se je kmetijstvu pričelo pripisovati številne nove funkcije, od socialne do ekološke. Z vključitvijo v EU in uveljavljanjem Skupne kmetijske politike prihaja do velikih sprememb tudi v slovenskem kmetijstvu, njegovi usmeritvi, stopnji intenzivnosti, velikostni in posestni strukturi. Vprašanje pa je, ali je smer razvoja kmetijstva v Sloveniji v skladu z varovanjem in ohranjanjem naših ključnih naravnih virov?The role of agriculture in rural areas has changed significantly, it has even increased, since having been attributed numerous new functions, from social to ecologic. Also Slovene agriculture, its direction, intensity level, size and proprietal structure was subject to considerable changes as a result of inclusion of Slovenia in the EU and implementation of the Common Agricultural Policy. However it should be considered whether the direction of development of Slovene agriculture corresponds to protection and conservation of our major natural resources

In vitro Hemocompatibility Assessment of Near-IR-Emitting Ag2S Quantum Dots (QD)

Quantum Dots (QDs) emitting in the Near-Infrared region (NIRQD) are relatively new but more attractive in biotechnology and medicine, than widely used visible QDs. However, heavy metal toxicity is an important concern for their parenteral applications. Recent efforts have been directed towards development of Cd, Pb and Hg free, biocompatible QDs. Hocaoglu et al. have recently demonstrated a single-step synthesis of cytocompatible Ag2S-2MPA NIRQDs via direct addition of sulphur source to silver salt 1. Till now, very few studies have assessed the hemocompatibility of QDs. Indeed, when diluted in the blood stream nanomaterials will be able to elicit several toxicological reactions, in particular: embolisation, hemolysis, cellular activation, but also several well-known biological cascades such as coagulation, complement activation, kinin/kininogen, fibrinolysis. Compared to macroscopic materials, hemoreactivity of nanoparticles may be expected to be significantly enhanced due to very high surface/volume ratio. It is therefore easy to realize that nanoparticles may significantly interact with humoral and cellular blood components of the blood 2

In vitro Hemocompatibility Assessment of Near-IR-Emitting Ag2S Quantum Dots (QD)

Quantum Dots (QDs) emitting in the Near-Infrared region (NIRQD) are relatively new but more attractive in biotechnology and medicine, than widely used visible QDs. However, heavy metal toxicity is an important concern for their parenteral applications. Recent efforts have been directed towards development of Cd, Pb and Hg free, biocompatible QDs. Hocaoglu et al. have recently demonstrated a single-step synthesis of cytocompatible Ag2S-2MPA NIRQDs via direct addition of sulphur source to silver salt 1. Till now, very few studies have assessed the hemocompatibility of QDs. Indeed, when diluted in the blood stream nanomaterials will be able to elicit several toxicological reactions, in particular: embolisation, hemolysis, cellular activation, but also several well-known biological cascades such as coagulation, complement activation, kinin/kininogen, fibrinolysis. Compared to macroscopic materials, hemoreactivity of nanoparticles may be expected to be significantly enhanced due to very high surface/volume ratio. It is therefore easy to realize that nanoparticles may significantly interact with humoral and cellular blood components of the blood 2

Preparation and characterization of antibacterial Senegalia (Acacia) senegal/iron-silica bio-nanocomposites

Many studies that research bio-nanocomposites utilize techniques that involve the dispersion of strengthening components like silica, metal and metal oxides through a host biopolymer matrix. The biggest success factor for the bio-nanocomposite is having a smooth integration of organic and inorganic phases. This interattraction between the surfaces of inorganic particles and organic molecules are vital for good dispersion. In this study, a novel biodegradable antibacterial material was developed using gum arabic from Senegalia senegal (stabilizer), silica (structure reinforcer) and zero valent iron particles. Silica particles work to not only strengthen the mechanical properties of the Senegalia senegal but also prevent the accumulation of ZVI nanoparticles due to attraction between hydroxyl groups and FeO. The gum arabic/Fe-SiO2 bio-nanocomposite showed effective antibacterial property against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coll. Using Scanning electron microscopy, homogeneous dispersion and uniform particle size was viewed in the biopolymer. X-ray diffraction studies of iron particles organization in Senegalia senegal also showed that the main portion of iron was crystalline and in the form of FeO and Fe. X-ray photoelectron spectroscopy was used to evaluate the chemical composition of the surface but no appreciable peak was measured for the iron before Ar etching. These results suggest that the surface of iron nanoparticles consist mainly of a layer of iron oxides in the form of FeO. Thermal gravimetric analysis was used to determine the thermal stability and absorbed moisture content. (C) 2015 Elsevier B.V. All rights reserved