Identification and quantification of seven volatile n-nitrosamines in cosmetics using gas chromatography/chemical ionization-mass spectrometry coupled with head space-solid phase microextraction

Choi, N.R.,Kim, Y.P.,Ji, W.H.,Hwang, G.S.,Ahn, Y.G. Pergamon Press ; Elsevier Science Ltd 2016 Talanta Vol.148 No.-

<P>An analytical method was developed for the identification and quantification of seven volatile n-nitrosamines (n-nitrosodimethylamine [NDMA], n-nitrosoethylmethylamine [NMEA], n-nitrosodiethylamine [NDEA], n-nitrosodipropylamine [NDPA], n-nitrosodibutylamine [NDBA], n-nitrosopiperidine [NPIP], and n-nitrosopyrrolidine [NPYRD]) in water insoluble cream type cosmetics. It was found that the head space-solid phase microextraction (HS-SPME) was suitable for extraction, clean up, and pre-concentration of n-nitrosamines in the cream type samples so its optimal conditions were investigated. Identification and quantification of n-nitrosamines using single quadrupole gas chromatography/mass spectrometry (GC/MS) in chemical ionization (CI) mode were carried out with accurate mass measurements. Their accurate masses of protonated molecular ions were obtained within 10 mDa of the theoretical masses when sufficiently high signal was acquired from the unique calibration method using mass and isotope accuracy. For the method validation of quantification, spiking experiments were carried out to determine the linearity, recovery, and method detection limit (MDL) using three deuterated internal standards. The average recovery was 79% within 20% relative standard deviation (RSD) at the concentration of 50 ng/g. MDLs ranged from 0.46 ng/g to 36.54 ng/g, which was satisfactory for the directive limit of 50 ng/g proposed by the European Commission (EC). As a result, it was concluded that the method could be provided for the accurate mass screening, confirmation, and quantification of n-nitrosamines when applied to cosmetic inspection. (C) 2015 Elsevier B.V. All rights reserved.</P>

Rumen Parameters and Urea Kinetics in Goats and Sheep

Darlis, N. Abdullah,Halim, R.A.,Jalaludin, S.,Ho, Y.W. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.7

The effects of animal species and supplements on rumen fluid characteristics, plasma urea-N (PUN) concentration, plasma urea-N pool size, urea-N degradation in the gut and urea-N net flux (urea-N synthesis rate) were studied in goats and sheep, with some minor differences detected. The animals were fed either chopped rice straw ad libitum+200 g soybean meal (SBM), or chopped rice straw ad libitum+190 g soybean meal+300 g sago meal (SBM+SM) for 14 days. The supplements were isonitrogenous (80 g crude protein/animal/d). [$^{14}C$]-urea was used as the marker for urea metabolism studies. Two animals from each species were fed either supplement in a cross-over design in two periods. The results showed that rumen pH was significantly (p<0.001) lower in animals fed SBM+SM than those fed SBM supplement. The ammonia concentrations of rumen fluid were significantly (p<0.01) higher in sheep (382.9 mg N/L) than goats (363.1 mg N/L) when fed SBM supplement but lower (282.5 mg N/L) than that of goats (311.0 mg N/L) when fed SBM+SM supplement. Total VFA concentrations were significantly (p<0.05) higher in animals fed SBM+SM supplement than those fed SBM supplement. Goats had significantly (p<0.01) higher molar proportions of acetate (79.1, 77.7%, respectively) than sheep (75.8, 74.0%, respectively) in both supplements. The molar proportion of acetate was significantly (p<0.05) higher, while that of butyrate lower in animals fed SBM supplement than those fed SBM+SM supplement. In animals fed SBM supplement, the molar proportion of propionate was significantly (p<0.01) higher in sheep (18.0%) than in goats (15.6%), but in animals fed SBM+SM, the molar proportion of butyrate was significantly (p<0.01) higher (9.6%) in sheep than in goats (7.2%). Plasma urea-N concentration, plasma urea-N pool size, urea-N degradation in the gut, urea-N net flux and the fraction of urea-C from the blood entering the rumen were not significantly different between goats and sheep fed either supplement. However, PUN concentration was significantly (p<0.05) lower in animals fed SBM+SM supplement (average of 13.8 mg N/100 ml) than in those fed SBM supplement (average of 16.5 mg N/100 ml). The urea net flux was significantly (p<0.05) higher in goats (average of 14.5 g N/d) than sheep (average of 12.9 g N/d), and animals fed SBM supplement showed higher (average of 14.9 g N/d) urea net flux than animals fed SBM+SM supplement (average of 12.9 g N/d). A significant (p<0.05) positive correlation was observed between urea-N net flux and urea-N degradation; urea-N net flux and pool size; urea-N net flux and urea excretion in the urine; and PUN and rumen ammonia in goats. While in sheep, significant (p<0.05) positive correlation was observed between urea-N net flux and urea excretion in the urine; and PUN and rumen ammonia.

Neutron-Induced Activation Cross Sections on Hafnium Isotopes from the Threshold to 20 MeV

V. Semkova,N. Janeva,N. Koyumdjieva,R. Jaime Tornin,A. Moens,A. J. M. Plompen,K. Volev 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Results of new cross section measurements are presented for the following neutron-induced reactions: ^(178)Hf(n,α)^(175)Yb, ^(180)Hf(n,α)^(177)Yb, ^(177)Hf(n,p)^(177)Lu^g, ^(178)Hf(n,x)^(177)Lu^g, ^(180)Hf(n,p)^(180)Lu, ^(180)Hf(n,n'α)^(180)Hf^m, ^(174)Hf(n,2n) ^(173)Hf, ^(176)Hf(n,2n)^(175)Hf, and ^(177)Hf(n,3n)^(175)Hf obtained with the activation technique. The irradiations were carried out at the 7-MV Van de Graaff accelerator at IRMM, Geel. Quasi monoenergetic neutrons with energies between 14.8 and 20.5 MeV were produced via the ^3H(d,n)^4He reaction at E_d = 1, 1.4, 2, 3, and 4 MeV. The ^3H(p,n)^3He reaction was employed for the production of neutrons in the 2 - 3 MeV energy range. Both natural and enriched samples were used to facilitate correction for interference between reactions leading to the same product. The radioactivity of the samples was determined by standard γ-ray spectrometry using HPGe detector. The current measurements are compared with the data from other authors and Evaluated Nuclear Data Files. Cross sections for three of the studied reactions are reported for the first time.

반추위내 (反芻胃內) Cellulolytic bacteria 의 분리 동정 (同定) 및 Activity 에 관한 연구 (2) 반추위내 Cellulolytic bacteria 의 Activity 에 관한 연구

민병렬(B . R . Min),맹원재(W . J . Maeng),조남기(N . K . Cho) 한국영양사료학회 1991 韓國營養飼料學會誌 Vol.15 No.3

Distributed and Nonsteady-State Model of an Air Cooler Working with R22 and R410A

R. O. Nunes,L. F. N. Castro,L. Machado,R. N. N. Koury 대한설비공학회 2016 International Journal of Air-Conditioning and Refr Vol.24 No.2

The restrictions imposed by Montreal Protocol for use of CFCs fluids and Kyoto Protocol to HCFCs have motivated researchers and the industry to seek new alternatives. Within this context, R410A has emerged as one of the most likely replacement of R22. The purpose of this work is to develop a numerical model of an air cooler to simulate its behavior operating under dynamic conditions loaded with R22 or R410A refrigerant. The model divides the air cooler in volumes control in which mass, energy, and momentum balance equations are applied and solved. Theoretical data obtained by model simulations repeated tendencies observed in experimental data taken from literature. Model simulations have also shown that for a step change in the inlet refrigerant mass flow, the superheating response of air cooler is almost the same when it is working with R22 or R410A refrigerant.

Microstructural, chemical states and electrical properties of Au/CuO/n-InP heterojunction with a cupric oxide interlayer

Balaram, N.,Rajagopal Reddy, V.,Sekhar Reddy, P.R.,Janardhanam, V.,Choi, Chel-Jong Elsevier 2018 Vacuum Vol.152 No.-

<P><B>Abstract</B></P> <P>Cupric oxide (CuO) is synthesized by simple chemical bath deposition method and deposited on n-type InP substrate using e-beam evaporation technique. First, the structural and chemical compositional analysis of CuO/n-InP are analysed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD and XPS results confirmed that the formation of CuO on n-type InP substrate. Then, Au/CuO/n-InP heterojunction is fabricated with a CuO interlayer and correlated its results with the Au/n-InP Schottky junction (SJ). The barrier height (Φ<SUB>b</SUB>) and ideality factor (n) are extracted through I-V and C-V methods and the respective values are 0.66 eV (I-V)/0.80 eV (C-V) and 1.24, and 0.78 eV (I-V)/0.94 eV (C-V) and 1.62 for the SJ and HJ diodes, respectively. By applying Cheung's and Norde functions, the Φ<SUB>b</SUB>, ideality factor and series resistance (R<SUB>S</SUB>) are derived for the SJ and HJ diodes. The derived interface state density (N<SUB>SS</SUB>) of HJ is lower than the SJ; results demonstrated that the CuO interlayer plays an important role in the decreased N<SUB>SS</SUB>. The Poole-Frenkel emission is the dominant current conduction mechanism in reverse bias of both SJ and HJ diodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Structural and chemical properties of CuO films are analysed by XRD and XPS. </LI> <LI> Barrier height of Au/n-InP SJ was modified by CuO interlayer. </LI> <LI> Heterojunction has a good rectification ratio compared to the Schottky junction. </LI> <LI> The interface state density of HJ is lower as compared to the SJ. </LI> <LI> Poole-Frenkel mechanism is found to dominate in both SJ and HJs. </LI> </UL> </P>

Synthesis, Spectral Properties and DFT Calculations of new Ruthenium (II) Polypyridyl Complexes; DNA Binding Affinity and in Vitro Cytotoxicity Activity

Mallepally, R. R.,Chintakuntla, N.,Putta, V. R.,K, N.,Vuradi, R. K.,P, M.,S, S. S.,Chitumalla, R. K.,Jang, J.,Penumaka, N. Springer Science + Business Media 2017 Journal of fluorescence Vol.27 No.4

<P>In this paper a novel ligand debip (2-(4-N,N-diethylbenzenamine)1H-imidazo[4,5-f] [1, 10]phenanthroline) and its Ru(II) polypyridyl complexes [Ru(L)(2)(debip)](2+), (L = phen (1), bpy (2) and dmb (3)) have been synthesized and characterized by spectroscopic techniques. The DNA binding studies for all these complexes were examined by absorption, emission, quenching studies, viscosity measurements and cyclic voltammetry. The light switching properties of complexes 1-3 have been evaluated. Molecular docking, Density Functional Theory (DFT) and time dependent DFT calculations were performed. The Ru(II) complexes exhibited efficient photocleavage activity against pBR322 DNA upon irradiation and exhibited good antimicrobial activity. Also investigated 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, lactate dehydrogenase (LDH) release assay and reactive oxygen species (ROS) against selected cancer cell lines (HeLa, PC3, Lancap, MCF-7 and MD-MBA 231).</P>

Experimental Investigation of a Walk-in Refrigerator Performance Using R290 as a Retrofit for R22

A. R. El-Sayed,M. El Morsi,N. A. Mahmoud 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.4

An experimental performance study is performed on a refrigeration system equipped with a scroll compressor and tested with R22 using an electronic expansion valve (EEV) as an expansion device and controlled by proportional-integral-derivative (PID) control method. The system is tested at −12∘C, −8∘C, −4∘C, 0∘C and 4∘C evaporator air temperature and 20∘C, 25∘C and 30∘C condenser inlet water temperature at 50 Hz compressor driving frequency and 50Hz evaporator fans driving frequency. R22 reached the set point at all temperatures except −12∘C evaporator temperature with 30∘C condenser temperature due to the severe increase in the compressor discharge temperature that could result in the lubricating oil burnout. Then, the system is retrofitted with a reciprocating compressor especially designed to be used with R290 and tested with R290 at the same evaporator and condenser temperatures using EEV as an expansion device. R290 reached all set points at all evaporator and condenser temperatures. Also, R290 was able to reach all evaporator temperatures at higher condenser temperatures, 35∘C and 40∘C, and this will be discussed in future work. The results show that using R290, the pulldown time decreases by 30.3–71.4%, the ON time ratio decreases by 1–23.6%, the compressor discharge temperature decreases by 46.6–81∘C, the refrigerant mass flow rate decreases by 28.8–50.4%, VRC decreases by 15.2–32.5%, the compressor power consumption decreases by 34.4–44.3% and coefficient of performance (COP) increases by 35–115.5%.

Do government subsidies stimulate firms’ R&D efforts? Empirical evidence from China

Sun Xiaohua,Yu Runqun,Wang Yun,Colombage Sisira R. N. 기술경영경제학회 2020 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.28 No.2

Government subsidies have been one of the popular policy instruments to stimulate firms’ R&D activities. We empirically investigate the impact of government subsidies on firms’ R&D decisions of listed manufacturing firms in China. In contrast to prior studies, we split firms’ R&D decision into two elements of ‘whether to invest decision’ and ‘how much to invest decision’. The influences and mechanism of government subsidies on R&D decision are theoretically analysed to develop hypotheses tested in this study. We find that government subsidies have a promotion effect on both elements of the firms’ R&D decision. Moreover, we also demonstrate the heterogeneous effects of government subsidies between state-owned and non-state firms. Due to the inherent principal-agent problem of state-owned firms and soft budget constraint, subsidies can only increase the probability to undertake R&D activities but cannot stimulate further investment in R&D efforts. However, our results indicate that government subsidies take effects in both elements of R&D decision for non-state firms.

Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au + Au collisions at_sNN=200GeV

Adare, A.,Afanasiev, S.,Aidala, C.,Ajitanand, N. N.,Akiba, Y.,Al-Bataineh, H.,Alexander, J.,Aoki, K.,Aramaki, Y.,Atomssa, E. T.,Averbeck, R.,Awes, T. C.,Azmoun, B.,Babintsev, V.,Bai, M.,Baksay, G.,Bak American Physical Society 2016 Physical Review C Vol.93 No.5

<P>Measurements of the anisotropic flow coefficients v(2){Psi(2)}, v(3){Psi(3)}, v(4){Psi(4)}, and v(4){Psi(2)} for identified particles (pi(+/-), K-+/-, and p + (p) over bar) at midrapidity, obtained relative to the event planes Psi(m) at forward rapidities in Au + Au collisions at root s(NN) = 200 GeV, are presented as a function of collision centrality and particle transverse momenta p(T). The v(n) coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic n, a modified valence quark-number N-q scaling [plotting v(n){Psi(m)}/(N-q)(n/2) versus transverse kinetic energies (KET)/N-q] is observed to yield a single curve for all the measured particle species for a broad range of KET. A simultaneous blast-wave model fit to the observed v(n){Psi(m)}(p(T)) coefficients and published particle spectra identifies radial flow anisotropies rho(n){Psi(m)} and spatial eccentricities s(n){Psi(m)} at freeze-out. These are generally smaller than the initial-state participant-plane geometric eccentricities epsilon(n){Psi(PP)(m)} as also observed in the final eccentricity from quantum interferometry measurements with respect to the event plane.</P>