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Sample records for positively charged organophosphorus

  1. Sol-gel niobia sorbent with a positively charged octadecyl ligand providing enhanced enrichment of nucleotides and organophosphorus pesticides in capillary microextraction for online HPLC analysis.

    Science.gov (United States)

    Kesani, Sheshanka; Malik, Abdul

    2018-04-01

    A niobia-based sol-gel organic-inorganic hybrid sorbent carrying a positively charged C 18 ligand (Nb 2 O 5 -C 18 (+ve)) was synthesized to achieve enhanced enrichment capability in capillary microextraction of organophosphorus compounds (which include organophosphorus pesticides and nucleotides) before their online analysis by high-performance liquid chromatography. The sorbent was designed to simultaneously provide three different types of molecular level interactions: electrostatic, Lewis acid-base, and van der Waals interactions. To understand relative contributions of various molecular level analyte-sorbent interactions in the extraction process, two other sol-gel niobia sorbents were also created: (a) a purely inorganic sol-gel niobia sorbent (Nb 2 O 5 ) and (b) an organic-inorganic hybrid sol-gel niobia sorbent carrying an electrically neutral-bonded octadecyl ligand (Nb 2 O 5 -C 18 ). The extraction efficiency of the created sol-gel niobia sorbent (Nb 2 O 5 -C 18 (+ve)) was compared with that of analogously designed and synthesized titania-based sol-gel sorbent (TiO 2 -C 18 (+ve)), taking into consideration that titania-based sorbents present state-of-the-art extraction media for organophosphorus compounds. In capillary microextraction with high-performance liquid chromatography analysis, Nb 2 O 5 -C 18 (+ve) had shown 40-50% higher specific extraction values (a measure of extraction efficiency) over that of TiO 2 -C 18 (+ve). Compared to TiO 2 -C 18 (+ve), Nb 2 O 5 -C 18 (+ve) also provided superior analyte desorption efficiency (96 vs. 90%) during the online release of the extracted organophosphorus pesticides from the sorbent coating in the capillary microextraction capillary to the chromatographic column using reversed-phase high-performance liquid chromatography mobile phase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Selectivity improvement of positive photoionization ion mobility spectrometry for rapid detection of organophosphorus pesticides by switching dopant concentration.

    Science.gov (United States)

    Zhou, Qinghua; Li, Jia; Wang, Bin; Wang, Shuang; Li, Haiyang; Chen, Jinyuan

    2018-01-01

    Ion mobility spectrometry (IMS) opened a potential avenue for the rapid detection of organophosphorus pesticides (OPPs), though an improved selectivity of stand-alone IMS was still in high demand. In this study, a stand-alone positive photoionization ion mobility spectrometry (PP-IMS) apparatus was constructed for the rapid detection of OPPs with acetone as dopant. The photoionization of acetone molecules was induced by the ultraviolet irradiation to produce the reactant ions (Ac) 2 H + , which were employed to ionize the OPPs including fenthion, imidan, phosphamidon, dursban, dimethoate and isocarbophos via the proton transfer reaction. Due to the difference in proton affinity, the tested OPPs exhibited the different dopant-dependent manners. Based on this observation, the switching of dopant concentration was implemented to improve the selectivity of PP-IMS for OPPs detection. For instance, a mixture of fenthion, dursban and dimethoate was tested. By switching the concentration of doped acetone from 0.07 to 2.33 to 19.94mgL -1 , the ion peaks of fenthion and dursban were inhibited in succession, achieving the selective detection of dimethoate at last. In addition, another mixture of imidan and phosphamidon was initially detected by PP-IMS with a dose of 0.07mgL -1 acetone, indicating that their ion peaks were severely overlapped; when the concentration of doped acetone was switched to 19.94mgL -1 , the inhibition of imidan signals promised the accurate identification of phosphamidon in mixture. Finally, the PP-IMS in combination of switching dopant concentration was applied to detect the mixed fenthion, dursban and dimethoate in Chinese cabbage, demonstrating the applicability of proposed method to real samples. Copyright © 2017. Published by Elsevier B.V.

  3. Radiation from Accelerating Electric Charges: The Third Derivative of Position

    Science.gov (United States)

    Butterworth, Edward

    2010-03-01

    While some textbooks appear to suggest that acceleration of an electric charge is both a necessary and sufficient cause for the generation of electromagnetic radiation, the question has in fact had an intricate and involved history. In particular, the acceleration of a charge in hyperbolic motion, the behavior of a charge supported against a gravitational force (and its implications for the Equivalence Principle), and a charge accelerated by a workless constraint have been the subject of repeated investigation. The present paper examines specifically the manner in which the third derivative of position enters into the equations of motion, and the implications this has for the emission of radiation. Plass opens his review article with the statement that ``A fundamental property of all charged particles is that electromagnetic energy is radiated whenever they are accelerated'' (Plass 1961; emphasis mine). His treatment of the equations of motion, however, emphasizes the importance of the occurrence of the third derivative of position therein, present in linear motion only when the rate of acceleration is increasing or decreasing. There appears to be general agreement that the presence of a nonzero third derivative indicates that this charge is radiating; but does its absence preclude radiation? This question leads back to the issues of charges accelerated by a uniform gravitational field. We will examine the equations of motion as presented in Fulton & Rohrlich (1960), Plass (1961), Barut (1964), Teitelboim (1970) and Mo & Papas (1971) in the light of more recent literature in an attempt to clarify this question.

  4. Positive, Neutral, and Negative Mass-Charges in General Relativity

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2006-07-01

    Full Text Available As shown, any four-dimensional proper vector has two observable projections onto time line, attributed to our world and the mirror world (for a mass-bearing particle, the projections posses are attributed to positive and negative mass-charges. As predicted, there should be a class of neutrally mass-charged particles that inhabit neither our world nor the mirror world. Inside the space-time area (membrane the space rotates at the light speed, and all particles move at as well the light speed. So, the predicted particles of the neutrally mass-charged class should seem as light-like vortices.

  5. Position Reconstruction and Charge Distribution in LHCb VELO Silicon Sensors

    CERN Document Server

    Versloot, TW; Akiba, K; Artuso, M; Van Beuzekom, M; Borel, J; Bowcock, TJV; Buytaert, J; Collins, P; Dumps, R; Dwyer, L; Eckstein, D; Eklund, L; Ferro-Luzzi, M; Frei, R; Gersabek M; Haefeli, G; Hennessy, K; Huse, T; Jans, E; John, M; Ketel, TJ; Keune, A; Lastoviicka, T; Mountain, R; Neufeld, N; Parkes, C; Stone, S; Szumlak, T; Tobin, M; Van Lysebetten, A; Viret, S; De Vries, H; Wang, J

    2007-01-01

    In 2006, a partially equipped LHCb VELO detector half was characterised in a test beam experiment (Alignment Challenge and Detector Commissioning, ACDC3). The position reconstruction and resolution for 2-strip R-sensor clusters was studied as a function of strip pitch and track inclination on the sensor surface. The Charge Density Distribution (CDD) is derived from the weighted charge distribution. It becomes asymmetric for tracks non-perpendicular to the strip surface. It is shown that the asymmetric broadening of the CDD around the track intercept position results in a linear eta-function at higher angles (>6 degrees). The sensor spatial resolution is determined both using a linear weighted mean of strip charges, as well as a third-order polynomial approximation via a eta-correction. The experimental results are in agreement with previous simulations. Future studies are underway to determine the angle and pitch dependent parameters which will be implemented in the LHCb VELO cluster position software tools.

  6. Method and apparatus for positioning a beam of charged particles

    International Nuclear Information System (INIS)

    Michail, M.S.; Woodard, O.C.; Yourke, H.S.

    1975-01-01

    A beam of charged particles is stepped from one predetermined position to another to form a desired pattern on a semiconductor wafer. There is a dynamic correction for the deviation of the actual position of the beam from its predetermined position, so that the beam is applied to the deviated position rather than the predetermined position. Through the location of four registration marks, the writing field is precisely defined. Writing fields may be interconnected by the sharing of registration marks, enabling the construction of chips which are larger than a single writing field. (auth)

  7. The organophosphorus extractants

    International Nuclear Information System (INIS)

    Zaoul, B.; Attou, M.; Azzouz, A.

    1989-07-01

    This work consists in a bibliographic review dealing with phosphorus and organophosphorus compounds chemistry and especially with the main extracting agents used in uranium ore treatment. In this context, a special interest is devoted to TBP, D 2 EHPA and TOPO. The content of this work is based on a large bibliography including cca. One hundred references related to many aspects concerning as well the nomenclature, the classification and the chemical structures of the organophosphorus compounds as synthesis methods, purification and analysis of the main extracting agents used in uranium extraction

  8. Charging and heat collection by a positively charged dust grain in a plasma.

    Science.gov (United States)

    Delzanno, Gian Luca; Tang, Xian-Zhu

    2014-07-18

    Dust particulates immersed in a quasineutral plasma can emit electrons in several important applications. Once electron emission becomes strong enough, the dust enters the positively charged regime where the conventional orbital-motion-limited (OML) theory can break down due to potential-well effects on trapped electrons. A minimal modification of the trapped-passing boundary approximation in the so-called OML(+) approach is shown to accurately predict the dust charge and heat collection flux for a wide range of dust size and temperature.

  9. QSAR for cholinesterase inhibition by organophosphorus esters and CNDO/2 calculations for organophosphorus ester hydrolysis

    Science.gov (United States)

    Johnson, H.; Kenley, R. A.; Rynard, C.; Golub, M. A.

    1985-01-01

    Quantitative structure-activity relationships were derived for acetyl- and butyrylcholinesterase inhibition by various organophosphorus esters. Bimolecular inhibition rate constants correlate well with hydrophobic substituent constants, and with the presence or absence of catonic groups on the inhibitor, but not with steric substituent constants. CNDO/2 calculations were performed on a separate set of organophosphorus esters, RR'P(O)X, where R and R' are alkyl and/or alkoxy groups and X is fluorine, chlorine or a phenoxy group. For each subset with the same X, the CNDO-derived net atomic charge at the central phosphorus atom in the ester correlates well with the alkaline hydrolysis rate constant. For the whole set of esters with different X, two equations were derived that relate either charge and leaving group steric bulk, or orbital energy and bond order to the hydrogen hydrolysis rate constant.

  10. Small interfering RNA delivery through positively charged polymer nanoparticles

    International Nuclear Information System (INIS)

    Dragoni, Luca; Cesana, Alberto; Moscatelli, Davide; Ferrari, Raffaele; Morbidelli, Massimo; Lupi, Monica; Falcetta, Francesca; Ubezio, Paolo; D’Incalci, Maurizio

    2016-01-01

    Small interfering RNA (siRNA) is receiving increasing attention with regard to the treatment of many genetic diseases, both acquired and hereditary, such as cancer and diabetes. Being a high molecular weight (MW) polyanion, siRNA is not able to cross a cell membrane, and in addition it is unstable in physiological conditions. Accordingly, a biocompatible nanocarrier able to deliver siRNA into cells is needed. In this work, we synthesized biocompatible positively charged nanoparticles (NPs) following a two-step process that involves ring opening polymerization (ROP) and emulsion free radical polymerization (EFRP). Firstly, we proved the possibility of fine tuning the NPs’ characteristics (e.g. size and surface charge) by changing the synthetic process parameters. Then the capability in loading and delivering undamaged siRNA into a cancer cell cytoplasm has been shown. This latter process occurs through the biodegradation of the polymer constituting the NPs, whose kinetics can be tuned by adjusting the polymer’s MW. Finally, the ability of NPs to carry siRNA inside the cells in order to inhibit their target gene has been demonstrated using green flourescent protein positive cells. (paper)

  11. Organophosphorus poisoning (acute).

    Science.gov (United States)

    Blain, Peter G

    2011-05-17

    Acetylcholinesterase inhibition by organophosphorus pesticides or organophosphate nerve agents can cause acute parasympathetic system dysfunction, muscle weakness, seizures, coma, and respiratory failure. Prognosis depends on the dose and relative toxicity of the specific compound, as well as pharmacokinetic factors. We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for acute organophosphorus poisoning? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 62 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: activated charcoal (single or multiple doses), alpha(2) adrenergic receptor agonists, atropine, benzodiazepines, butyrylcholinesterase replacement therapy, cathartics, extracorporeal clearance, gastric lavage, glycopyrronium bromide (glycopyrrolate), ipecacuanha (ipecac), magnesium sulphate, milk or other home remedy immediately after ingestion, N-methyl-D-aspartate receptor antagonists, organophosphorus hydrolases, oximes, removing contaminated clothes and washing the poisoned person, and sodium bicarbonate.

  12. Positively charged phosphorus as a hydrogen bond acceptor

    DEFF Research Database (Denmark)

    Hansen, Anne Schou; Du, Lin; Kjærgaard, Henrik Grum

    2014-01-01

    Phosphorus (P) is an element that is essential to the life of all organisms, and the atmospheric detection of phosphine suggests the existence of a volatile biogeochemical P cycle. Here, we investigate the ability of P to participate in the formation of OH···P hydrogen bonds. Three bimolecular......-stretching frequency red shifts and quantum chemical calculations, we find that P is an acceptor atom similar in strength to O and S and that all three P, O, and S atoms are weaker acceptors than N. The quantum chemical calculations show that both H and P in the OH···P hydrogen bond have partial positive charges......, as expected from their electronegativities. However, the electrostatic potentials show a negative potential area on the electron density surface around P that facilitates formation of hydrogen bonds....

  13. Charge dividing mechanism in position-sensitive detectors

    International Nuclear Information System (INIS)

    Radeka, V.; Rehak, P.

    1978-01-01

    A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistances and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2π (L/C)/sup 1/2), where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line

  14. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  15. Study of correlations of positive and negative charged particles

    International Nuclear Information System (INIS)

    Takahashi, Y.; Chan, C.H.; Dong, B.L.; Duthie, J.G.; Gregory, J.C.; Hayashi, T.; Yokomi, H.; Christl, M.J.; Derrickson, J.H.; Eby, P.B.; Fountain, W.F.; Parnell, T.A.; Roberts, F.E.; Nagamiya, S.; Dake, S.; Tominaga, T.; Fuki, M.; Iyono, A.; Ogata, T.; Miyamura, O.

    1991-01-01

    Particle correlations of the central collision events of 32 S + Pb at 200 GeV/AMU have been studied by utilizing a Magnetic-Interferomagnetic-Emulsion-Chamber (MAGIC) detector. Particle angles, momentum, and charge-signs are measured for all produced charged tracks for each event. Two-particle correlation functions, C 2 = dN (vertical strokep 1 - p 2 vertical stroke = q)/dp 1 dp 2 , for (++), (--) and (+-) particles are examined. A source radius around 4 - 6 fm is observed for overall identical particle correlations, while unexpected short-range correlations of unlike-sign pairs are observed in the high rapidity region. An analysis of unlike-sign pairs in terms of resonance decays indicated that a large amount (40% relative to pions) of η or ω mesons (decaying into 3 π), or of scalar iso-scalar σ mesons (decaying into 2 π) would be required to explain some of the data. Multi-particle charge-sign clusters are recognized; however, their 'run-test' and 'conjugate-test' show small deviations from statistical fluctuations. (orig.)

  16. Study of position resolution for cathode readout MWPC with measurement of induced charge distribution

    International Nuclear Information System (INIS)

    Chiba, J.; Iwasaki, H.; Kageyama, T.; Kuribayashi, S.; Nakamura, K.; Sumiyoshi, T.; Takeda, T.

    1983-01-01

    A readout technqiue of multiwire proportional chambers by measurement of charges induced on cathode strips, orthogonal to anode wires, requires an algorithm to relate the measured charge distribution to the avalanche position. With given chamber parameters and under the influence of noise, resolution limits depend on the chosen algorithm. We have studied the position resolution obtained by the centroid method and by the charge-ratio method, both using three consecutive cathode strips. While the centroid method uses a single number, the center of gravity of the measured charges, the charge-ratio method uses the ratios of the charges Qsub(i-1)/Qsub(i) and Qsub(i+1)/Qsub(i) where Qsub(i) is the largest. To obtain a given resolution, the charge-ratio method generally allows wider cathode strips and therefore a smaller number of readout channels than the centroid method. (orig.)

  17. Adsorption of cations onto positively charged surface mesopores.

    Science.gov (United States)

    Neue, Uwe; Iraneta, Pamela; Gritti, Fabrice; Guiochon, Georges

    2013-11-29

    Uwe Neue developed a theoretical treatment to account for the adsorption of ions on mesopores of packing materials the walls of which are bonded to ionic ligands but left this work unfinished. We elaborated upon this treatment and refined it, based on the equivalence that he suggested between charged surface particles and a membrane that separates two ionic solutions but is impermeable to one specification. He had written that the electro-chemical potentials in both ionic solutions are equal (Donnan equilibrium). The equilibrium between the surface and the pore concentrations is accounted for by an homogeneous electrostatically modified Langmuir (EML) isotherm model. The theoretical results are presented for four different charge surface concentrations σ0=0, 0.001, 0.002, and 0.003C/m(2), using a phosphate buffer (W(S)pH=2.65) of ionic strength I=10mM. The average pore size, the specific surface area, and the specific pore volume of the stationary phase were Dp=140Å, Sp=182m(2)/g, and Vp=0.70cm(3)/g, respectively. The theoretical results provide the quantitative difference between the ionic strength, the pH, and the concentrations of all the ions in the pores and in the bulk eluent. The theory predicts (1) that the retention times of cations under linear conditions is lower and (2) that their band widths under overloaded conditions for a given retention factor shrinks when the surface charge density σ0 is increased. These theoretical results are in good agreement with experimental results published previously and explain them. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seon Young; Jang, Soo Hwa [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of); Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su [Soongsil University, Department of Chemistry (Korea, Republic of); Lee, Kangtaek [Yonsei University, Department of Chemical and Biomolecular Engineering (Korea, Republic of); Yang, Sung Ik [Kyung Hee University, College of Environment and Applied Chemistry (Korea, Republic of); Joo, Sang-Woo, E-mail: sjoo@ssu.ac.kr [Soongsil University, Department of Chemistry (Korea, Republic of); Ryu, Pan Dong; Lee, So Yeong, E-mail: leeso@snu.ac.kr [Seoul National University, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Institute for Veterinary Science (Korea, Republic of)

    2012-12-15

    Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

  19. Cellular uptake and cytotoxicity of positively charged chitosan gold nanoparticles in human lung adenocarcinoma cells

    International Nuclear Information System (INIS)

    Choi, Seon Young; Jang, Soo Hwa; Park, Jin; Jeong, Saeromi; Park, Jin Ho; Ock, Kwang Su; Lee, Kangtaek; Yang, Sung Ik; Joo, Sang-Woo; Ryu, Pan Dong; Lee, So Yeong

    2012-01-01

    Cellular uptake, cytotoxicity, and mechanisms of cytotoxicity of the positively charged Au nanoparticles (NPs) were examined in A549 cells, which are one of the most characterized pulmonary cellular systems. Positively charged Au NPs were prepared by chemical reduction using chitosan. The dimension and surface charge of Au NPs were examined by transmission electron microscopy (TEM), dynamic light scattering, and zeta potential measurements. The uptake of Au NPs into A549 cells was also monitored using TEM and dark-field microscopy (DFM) and z-stack confocal microRaman spectroscopy. DFM live cell imaging was also performed to monitor the entry of chitosan Au NPs in real time. The cytotoxic assay, using both methylthiazol tetrazolium and lactate dehydrogenase assays revealed that positively charged Au NPs decreased cell viability. Flow cytometry, DNA fragmentation, real-time PCR, and western blot analysis suggest that positively charged chitosan Au NPs provoke cell damage through both apoptotic and necrotic pathways.

  20. Comparing Positively and Negatively Charged Distonic Radical Ions in Phenylperoxyl Forming Reactions.

    Science.gov (United States)

    Williams, Peggy E; Marshall, David L; Poad, Berwyck L J; Narreddula, Venkateswara R; Kirk, Benjamin B; Trevitt, Adam J; Blanksby, Stephen J

    2018-06-04

    In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature combustion and atmospheric processing of volatile organic compounds. We have previously demonstrated the application of charge-tagged phenyl radicals to explore the outcomes of these reactions using ion trap mass spectrometry. Here, we present a side-by-side comparison of rates and product distributions from the reaction of positively and negatively charge tagged phenyl radicals with dioxygen. The negatively charged distonic radical ions are found to react with significantly greater efficiency than their positively charged analogues. The product distributions of the anion reactions favor products of phenylperoxyl radical decomposition (e.g., phenoxyl radicals and cyclopentadienone), while the comparable fixed-charge cations yield the stabilized phenylperoxyl radical. Electronic structure calculations rationalize these differences as arising from the influence of the charged moiety on the energetics of rate-determining transition states and reaction intermediates within the phenylperoxyl reaction manifold and predict that this influence could extend to intra-molecular charge-radical separations of up to 14.5 Å. Experimental observations of reactions of the novel 4-(1-carboxylatoadamantyl)phenyl radical anion confirm that the influence of the charge on both rate and product distribution can be modulated by increasing the rigidly imposed separation between charge and radical sites. These findings provide a generalizable framework for predicting the influence of charged groups on polarizable radicals in gas phase distonic radical ions. Graphical Abstract.

  1. Energy distribution extraction of negative charges responsible for positive bias temperature instability

    International Nuclear Information System (INIS)

    Ren Shang-Qing; Yang Hong; Wang Wen-Wu; Tang Bo; Tang Zhao-Yun; Wang Xiao-Lei; Xu Hao; Luo Wei-Chun; Zhao Chao; Yan Jiang; Chen Da-Peng; Ye Tian-Chun

    2015-01-01

    A new method is proposed to extract the energy distribution of negative charges, which results from electron trapping by traps in the gate stack of nMOSFET during positive bias temperature instability (PBTI) stress based on the recovery measurement. In our case, the extracted energy distribution of negative charges shows an obvious dependence on energy, and the energy level of the largest energy density of negative charges is 0.01 eV above the conduction band of silicon. The charge energy distribution below that energy level shows strong dependence on the stress voltage. (paper)

  2. Two-dimensional position sensitive silicon photodiode as a charged particle detector

    International Nuclear Information System (INIS)

    Kovacevic, K.; Zadro, M.

    1999-01-01

    A two-dimensional position sensitive silicon photodiode has been tested for measurement of position and energy of charged particles. Position nonlinearity and resolution, as well as energy resolution and ballistic deficit were measured for 5.486 MeV α-particles. The results obtained for different pulse shaping time constants are presented

  3. 2D position sensitive microstrip sensors with charge division along the strip Studies on the position measurement error

    CERN Document Server

    Bassignana, D; Fernandez, M; Jaramillo, R; Lozano, M; Munoz, F.J; Pellegrini, G; Quirion, D; Vila, I; Vitorero, F

    2013-01-01

    Position sensitivity in semiconductor detectors of ionizing radiation is usually achieved by the segmentation of the sensing diode junction in many small sensing elements read out separately as in the case of conventional microstrips and pixel detectors. Alternatively, position sensitivity can be obtained by splitting the ionization signal collected by one single electrode amongst more than one readout channel with the ratio of the collected charges depending on the position where the signal was primary generated. Following this later approach, we implemented the charge division method in a conventional microstrip detector to obtain position sensitivity along the strip. We manufactured a proofof-concept demonstrator where the conventional aluminum electrodes were replaced by slightly resistive electrodes made of strongly doped poly-crystalline silicon and being readout at both strip ends. Here, we partially summarize the laser characterization of this first proof-of-concept demonstrator with special emphasis ...

  4. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

    Science.gov (United States)

    Zhao, Ling; Xia, Huifen

    2018-01-01

    The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

  5. The relation of electrode voltages to charge position in SLC arc and final focus beam position monitors

    International Nuclear Information System (INIS)

    Fordham, C.

    1989-01-01

    The position of a charged particle beam can be measured with a Beam Position Monitor (BPM) by converting the voltages induced on its array of electrodes into a position offset from the array's center. Most of the BPMs in the Arcs and Final Focus of the SLC use four stripline electrodes arranged symmetrically around the beam; normalized voltage differences are calculated as the difference divided by the sum of voltages on opposite electrode pairs. The resulting number is multiplied by a conversion factor, denoted in this paper as S b , to give the offset (in millimeters) of the charge from the center of the BPM. Prior to installation in the beam line, the BPMs were calibrated with a charge pulse on a rod. Owing to geometric effects which will be discussed later, a different conversion factor had to be used for calibration. It will be denoted here by S r . This paper gives the results of calculations and measurements of S r and S b for Arc and Final Focus BPMs. This paper also describes the relevant physical properties of the several types of BPMs and calculations of the expected scale factors, the measurement methods used, and gives the results of measurements, which are compared with the theoretical expectations. 2 refs., 18 figs., 7 tabs

  6. Development of a Sweetness Sensor for Aspartame, a Positively Charged High-Potency Sweetener

    Directory of Open Access Journals (Sweden)

    Masato Yasuura

    2014-04-01

    Full Text Available Taste evaluation technology has been developed by several methods, such as sensory tests, electronic tongues and a taste sensor based on lipid/polymer membranes. In particular, the taste sensor can individually quantify five basic tastes without multivariate analysis. However, it has proven difficult to develop a sweetness sensor, because sweeteners are classified into three types according to the electric charges in an aqueous solution; that is, no charge, negative charge and positive charge. Using membrane potential measurements, the taste-sensing system needs three types of sensor membrane for each electric charge type of sweetener. Since the commercially available sweetness sensor was only intended for uncharged sweeteners, a sweetness sensor for positively charged high-potency sweeteners such as aspartame was developed in this study. Using a lipid and plasticizers, we fabricated various lipid/polymer membranes for the sweetness sensor to identify the suitable components of the sensor membranes. As a result, one of the developed sensors showed responses of more than 20 mV to 10 mM aspartame and less than 5 mV to any other taste. The responses of the sensor depended on the concentration of aspartame. These results suggested that the developed sweetness sensor had high sensitivity to and high selectivity for aspartame.

  7. Development of a sweetness sensor for aspartame, a positively charged high-potency sweetener.

    Science.gov (United States)

    Yasuura, Masato; Tahara, Yusuke; Ikezaki, Hidekazu; Toko, Kiyoshi

    2014-04-23

    Taste evaluation technology has been developed by several methods, such as sensory tests, electronic tongues and a taste sensor based on lipid/polymer membranes. In particular, the taste sensor can individually quantify five basic tastes without multivariate analysis. However, it has proven difficult to develop a sweetness sensor, because sweeteners are classified into three types according to the electric charges in an aqueous solution; that is, no charge, negative charge and positive charge. Using membrane potential measurements, the taste-sensing system needs three types of sensor membrane for each electric charge type of sweetener. Since the commercially available sweetness sensor was only intended for uncharged sweeteners, a sweetness sensor for positively charged high-potency sweeteners such as aspartame was developed in this study. Using a lipid and plasticizers, we fabricated various lipid/polymer membranes for the sweetness sensor to identify the suitable components of the sensor membranes. As a result, one of the developed sensors showed responses of more than 20 mV to 10 mM aspartame and less than 5 mV to any other taste. The responses of the sensor depended on the concentration of aspartame. These results suggested that the developed sweetness sensor had high sensitivity to and high selectivity for aspartame.

  8. A two-dimensional position sensitive gas chamber with scanned charge transfer readout

    International Nuclear Information System (INIS)

    Gomez, F.; Iglesias, A.; Lobato, R.; Mosquera, J.; Pardo, J.; Pena, J.; Pazos, A.; Pombar, M.; Rodriguez, A.

    2003-01-01

    We have constructed and tested a two-dimensional position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position-dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solution reduces considerably the number of electronic readout channels needed to cover large detector areas. The use of a 25 μm thick kapton etched circuit allows high charge transfer efficiency with a low gating voltage, consequently needing a very simple commutating circuit. The present prototype covers 8x8 cm 2 with a pixel size of 1.27x1.27 mm 2 . Depending on the intended use and beam characteristics a smaller effective pixel is feasible and larger active areas are possible. This detector can be used for X-ray or other continuous beam intensity profile monitoring

  9. Mixed-mode reversed phase/positively charged repulsion chromatography for intact protein separation.

    Science.gov (United States)

    Ding, Ling; Guo, Zhimou; Hu, Zhuo; Liang, Xinmiao

    2017-05-10

    A mixed-mode reversed phase/positively charged repulsion stationary phase C8PN composed of octyl and amino group has been developed for separation of intact protein. Before the separation of proteins, a set of probe compounds were employed to evaluate the chromatographic properties of C8PN, demonstrating typical reversed phase/positively charged repulsion interaction on this stationary phase as estimated. Then the new C8PN stationary phase was used to separate a standard protein mixture on the reversed phase mode. Compared with a commercial C4 stationary phase, it showed different selectivity for some proteins. In order to better understand the properties of C8PN, the effect of acetonitrile content was investigated based on retention equation. Higher values of the equation parameters on C8PN demonstrated that the protein retentions were more sensitive to the change of acetonitrile content. Besides, the influences of buffer salt additives on the protein retentions were also studied. The retention factors of the proteins got larger with the increase of buffer salt concentration, which confirmed the positively charged repulsion interaction on the column. Finally, the C8PN was further applied to separate oxidized- and reduced- forms of Recombinant Human Growth Hormone. Our study indicated the advantages and application potential of mixed-mode reversed phase/positively charged repulsion stationary phase for intact protein separation. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. PEPTIDE SOLUBILITY, STRUCTURE AND CHARGE POSITION EFFECT ON ADSORPTION BY ALUMINIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Mary Trujillo

    2008-04-01

    Full Text Available Solubility, structure and position of charges in a peptide antigen sequence can be mentioned as being amongst the basic features of adsorption. In order to study their effect on adsorption, seven analogue series were synthesized from a MSP-1 peptide sequence by systematically replacing each one of the positions in the peptide sequence by aspartic acid, glutamic acid, serine, alanine, asparagine, glutamine or lysine. Such modifications in analogue peptide sequences showed a non-regular tendency regarding solubility and adsorption data. Aspartic acid and Glutamic acid analogue series showed great improvements in adsorption, especially in peptides where Lysine in position 6 and Arginine in position 13 were replaced. Solubility of position 5 analogue was greater than the position 6 analogue in Aspartic acid series; however, the position 6 analogue showed best adsorption results whilst the Aspartic acid in position 5 analogue showed no adsorption in the same conditions. Nuclear Magnetic Resonance structural analysis revealed differences in the -helical structureextension between these analogues. The Aspartic acid in position 6, located in the polar side of the helix, may allow this analogueto fit better onto the adsorption regions suggesting that the local electrostatic charge is responsible for this behavior.

  11. Organophosphorus pesticide poisoning : cases and developments

    NARCIS (Netherlands)

    Aardema, H.; Ligtenberg, J. J. M.; Peters-Polman, O. M.; Tulleken, J. E.; Zijlstra, J. G.; Meertens, John H. J. M.

    Self-poisoning with organophosphate pesticides is a major health problem world-wide. Through the inhibition of acetylcholinesterase, organophosphorus poisoning is characterised by the clinical picture of acute cholinergic crisis. Other manifestations are the intermediate neurotoxic syndrome and

  12. Method for purifying bidentate organophosphorus compounds

    International Nuclear Information System (INIS)

    Schulz, W.W.

    1977-01-01

    Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds

  13. Positively charged microporous ceramic membrane for the removal of Titan Yellow through electrostatic adsorption.

    Science.gov (United States)

    Cheng, Xiuting; Li, Na; Zhu, Mengfu; Zhang, Lili; Deng, Yu; Deng, Cheng

    2016-06-01

    To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane. The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421L/(m(2)·hr) under the trans-membrane pressure of 0.03bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10mg/L between pH3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater. Copyright © 2016. Published by Elsevier B.V.

  14. Positive zeta potential of a negatively charged semi-permeable plasma membrane

    Science.gov (United States)

    Sinha, Shayandev; Jing, Haoyuan; Das, Siddhartha

    2017-08-01

    The negative charge of the plasma membrane (PM) severely affects the nature of moieties that may enter or leave the cells and controls a large number of ion-interaction-mediated intracellular and extracellular events. In this letter, we report our discovery of a most fascinating scenario, where one interface (e.g., membrane-cytosol interface) of the negatively charged PM shows a positive surface (or ζ) potential, while the other interface (e.g., membrane-electrolyte interface) still shows a negative ζ potential. Therefore, we encounter a completely unexpected situation where an interface (e.g., membrane-cytosol interface) that has a negative surface charge density demonstrates a positive ζ potential. We establish that the attainment of such a property by the membrane can be ascribed to an interplay of the nature of the membrane semi-permeability and the electrostatics of the electric double layer established on either side of the charged membrane. We anticipate that such a membrane property can lead to such capabilities of the cell (in terms of accepting or releasing certain kinds of moieties as well regulating cellular signaling) that was hitherto inconceivable.

  15. Management of acute organophosphorus pesticide poisoning

    OpenAIRE

    Eddleston, Michael; Buckley, Nick A; Eyer, Peter; Dawson, Andrew H

    2008-01-01

    Summary Organophosphorus pesticide self-poisoning is an important clinical problem in rural regions of the developing world, and kills an estimated 200?000 people every year. Unintentional poisoning kills far fewer people but is a problem in places where highly toxic organophosphorus pesticides are available. Medical management is difficult, with case fatality generally more than 15%. We describe the limited evidence that can guide therapy and the factors that should be considered when design...

  16. Position readout by charge division in large two-dimensional detectors

    International Nuclear Information System (INIS)

    Alberi, J.L.

    1976-10-01

    The improvement in readout spatial resolution for charge division systems with subdivided readout electrodes has been analyzed. This readout forms the position and sum signals by a linear, unambiguous analogue summation technique. It is shown that the readout resolution is a function of only electrode capacitance and shaping parameters. The line width improves as 1/N/sup 1 / 2 /, where N is the number of electrode subdivisions

  17. Directional rolling of positively charged nanoparticles along a flexibility gradient on long DNA molecules.

    Science.gov (United States)

    Park, Suehyun; Joo, Heesun; Kim, Jun Soo

    2018-01-31

    Directing the motion of molecules/colloids in any specific direction is of great interest in many applications of chemistry, physics, and biological sciences, where regulated positioning or transportation of materials is highly desired. Using Brownian dynamics simulations of coarse-grained models of a long, double-stranded DNA molecule and positively charged nanoparticles, we observed that the motion of a single nanoparticle bound to and wrapped by the DNA molecule can be directed along a gradient of DNA local flexibility. The flexibility gradient is constructed along a 0.8 kilobase-pair DNA molecule such that local persistence length decreases gradually from 50 nm to 40 nm, mimicking a gradual change in sequence-dependent flexibility. Nanoparticles roll over a long DNA molecule from less flexible regions towards more flexible ones as a result of the decreasing energetic cost of DNA bending and wrapping. In addition, the rolling becomes slightly accelerated as the positive charge of nanoparticles decreases due to a lower free energy barrier of DNA detachment from charged nanoparticle for processive rolling. This study suggests that the variation in DNA local flexibility can be utilized in constructing and manipulating supramolecular assemblies of DNA molecules and nanoparticles in structural DNA nanotechnology.

  18. Reduction of digital errors of digital charge division type position-sensitive detectors

    International Nuclear Information System (INIS)

    Uritani, A.; Yoshimura, K.; Takenaka, Y.; Mori, C.

    1994-01-01

    It is well known that ''digital errors'', i.e. differential non-linearity, appear in a position profile of radiation interactions when the profile is obtained with a digital charge-division-type position-sensitive detector. Two methods are presented to reduce the digital errors. They are the methods using logarithmic amplifiers and a weighting function. The validities of these two methods have been evaluated mainly by computer simulation. These methods can considerably reduce the digital errors. The best results are obtained when both methods are applied. ((orig.))

  19. Study of electric field distorted by space charges under positive lightning impulse voltage

    Science.gov (United States)

    Wang, Zezhong; Geng, Yinan

    2018-03-01

    Actually, many insulation problems are related to electric fields. And measuring electric fields is an important research topic of high-voltage engineering. In particular, the electric field distortion caused by space charge is the basis of streamer theory, and thus quantitatively measuring the Poisson electric field caused by space charge is significant to researching the mechanism of air gap discharge. In this paper, we used our photoelectric integrated sensor to measure the electric field distribution in a 1-m rod-plane gap under positive lightning impulse voltage. To verify the reliability of this quantitative measurement, we compared the measured results with calculated results from a numerical simulation. The electric-field time domain waveforms on the axis of the 1-m rod-plane out of the space charge zone were measured with various electrodes. The Poisson electric fields generated by space charge were separated from the Laplace electric field generated by applied voltages, and the amplitudes and variations were measured for various applied voltages and at various locations. This work also supplies the feasible basis for directly measuring strong electric field under high voltage.

  20. Positive column of a glow discharge in neon with charged dust grains (a review)

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, D. N., E-mail: cryolab@ihed.ras.ru; Shumova, V. V.; Vasilyak, L. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2017-03-15

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  1. Positive column of a glow discharge in neon with charged dust grains (a review)

    International Nuclear Information System (INIS)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2017-01-01

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  2. Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

    Directory of Open Access Journals (Sweden)

    Sophie Letort

    2017-03-01

    Full Text Available New derivatives of cyclodextrins were prepared in order to determine the relative importance of the structural key elements involved in the degradation of organophosphorus nerve agents. To avoid a competitive inclusion between the organophosphorus substrate and the iodosobenzoate group, responsible for its degradation, the latter group had to be covalently bound to the cyclodextrin scaffold. Although the presence of the α nucleophile iodosobenzoate was a determinant in the hydrolysis process, an imidazole group was added to get a synergistic effect towards the degradation of the agents. The degradation efficiency was found to be dependent on the relative position of the heterocycle towards the reactive group as well as on the nature of the organophosphorus derivative.

  3. A two-dimensional position sensitive gas chamber with scanned charge transfer readout

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F. E-mail: faustgr@usc.es; Iglesias, A.; Lobato, R.; Mosquera, J.; Pardo, J.; Pena, J.; Pazos, A.; Pombar, M.; Rodriguez, A

    2003-10-21

    We have constructed and tested a two-dimensional position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position-dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solution reduces considerably the number of electronic readout channels needed to cover large detector areas. The use of a 25 {mu}m thick kapton etched circuit allows high charge transfer efficiency with a low gating voltage, consequently needing a very simple commutating circuit. The present prototype covers 8x8 cm{sup 2} with a pixel size of 1.27x1.27 mm{sup 2}. Depending on the intended use and beam characteristics a smaller effective pixel is feasible and larger active areas are possible. This detector can be used for X-ray or other continuous beam intensity profile monitoring.

  4. Microporous nano-MgO/diatomite ceramic membrane with high positive surface charge for tetracycline removal.

    Science.gov (United States)

    Meng, Xian; Liu, Zhimeng; Deng, Cheng; Zhu, Mengfu; Wang, Deyin; Li, Kui; Deng, Yu; Jiang, Mingming

    2016-12-15

    A novel microporous nano-MgO/diatomite ceramic membrane with high positive surface charge was prepared, including synthesis of precursor colloid, dip-coating and thermal decomposition. Combined SEM, EDS, XRD and XPS studies show the nano-MgO is irregularly distributed on the membrane surface or pore walls and forms a positively charged nano coating. And the nano-MgO coating is firmly attached to the diatomite membrane via SiO chemical bond. Thus the nano-MgO/diatomite membrane behaves strong electropositivity with the isoelectric point of 10.8. Preliminary filtration tests indicate that the as-prepared nano-MgO/diatomite membrane could remove approximately 99.7% of tetracycline in water through electrostatic adsorption effect. The desirable electrostatic property enables the nano-MgO/diatomite membrane to be a candidate for removal of organic pollutants from water. And it is convinced that there will be a great application prospect of charged ceramic membrane in water treatment field. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Negative and positive magnetoresistance in bilayer graphene: Effects of weak localization and charge inhomogeneity

    International Nuclear Information System (INIS)

    Chen Yungfu; Bae, Myung-Ho; Chialvo, Cesar; Dirks, Travis; Bezryadin, Alexey; Mason, Nadya

    2011-01-01

    We report measurements of magnetoresistance in bilayer graphene as a function of gate voltage (carrier density) and temperature. We examine multiple contributions to the magnetoresistance, including those of weak localization (WL), universal conductance fluctuations (UCF), and inhomogeneous charge transport. A clear WL signal is evident at all measured gate voltages (in the hole doped regime) and temperature ranges (from 0.25 to 4.3 K), and the phase coherence length extracted from the WL data does not saturate at low temperatures. The WL data is fit to demonstrate that the electron-electron Nyquist scattering is the major source of phase decoherence. A decrease in UCF amplitude with increase in gate voltage and temperature is shown to be consistent with a corresponding decrease in the phase coherence length. In addition, a weak positive magnetoresistance at higher magnetic fields is observed, and attributed to inhomogeneous charge transport. -- Research highlights: → Weak localization theory describes low-field magnetoresistance in bilayer graphene. → Electron-electron Nyquist scattering limits phase coherence in bilayer graphene. → Positive magnetoresistance reveals charge inhomogeneity in bilayer graphene.

  6. Simulation of the interaction of positively charged beams and electron clouds

    International Nuclear Information System (INIS)

    Markovik, Aleksandar

    2013-01-01

    The incoherent (head-tail) effect on the bunch due to the interaction with electron clouds (e-clouds) leads to a blow up of the transverse beam size in storage rings operating with positively charged beams. Even more the e-cloud effects are considered to be the main limiting factor for high current, high-brightness or high-luminosity operation of future machines. Therefore the simulation of e-cloud phenomena is a highly active field of research. The main focus in this work was set to a development of a tool for simulation of the interaction of relativistic bunches with non-relativistic parasitic charged particles. The result is the Particle-In-Cell Program MOEVE PIC Tracking which can track a 3D bunch under the influence of its own and external electromagnetic fields but first and foremost it simulates the interaction of relativistic positively charged bunches and initially static electrons. In MOEVE PIC Tracking the conducting beam pipe can be modeled with an arbitrary elliptical cross-section to achieve more accurate space charge field computations for both the bunch and the e-cloud. The simulation of the interaction between positron bunches and electron clouds in this work gave a detailed insight of the behavior of both particle species during and after the interaction. Further and ultimate goal of this work was a fast estimation of the beam stability under the influence of e-clouds in the storage ring. The standard approach to simulate the stability of a single bunch is to track the bunch particles through the linear optics of the machine by multiplying the 6D vector of each particle with the transformation matrices describing the lattice. Thereby the action of the e-cloud on the bunch is approximated by a pre-computed wake kick which is applied on one or more points in the lattice. Following the idea of K.Ohmi the wake kick was pre-computed as a two variable function of the bunch part exiting the e-cloud and the subsequent parts of a bunch which receive a

  7. SFG and SPR Study of Sodium Dodecyl Sulfate Film Assembly on Positively Charged Surfaces

    Science.gov (United States)

    Song, Sanghun; Weidner, Tobias; Wagner, Matthew; Castner, David

    2012-02-01

    This study uses sum frequency generation (SFG) vibrational spectroscopy and surface plasmon resonance (SPR) sensing to investigate the structure of sodium dodecyl sulfate (SDS) films formed on positively charged and hydrophilic surfaces. The SPR signals show a good surface coverage suggesting that full monolayer coverage is reached at 1 mM. SFG spectra of SDS adsorbed exhibits well resolved CH3 peaks and OH peaks. At both 0.2 mM and 1 mM SDS concentration the intensity of both the CH3 and OH peaks decreased close to background levels. We found that the loss of SFG signal at 0.2 mM occurs at this concentration independent of surface charge density. It is more likely that the loss of signal is related to structural inhomogeneity induced by a striped phase - stand-up phase transition. This is supported by a distinct change of the relative SFG phase between CH3/OH near 0.2 mM. The second intensity minimum might be related to charge compensation effects. We observed a substrate dependence for the high concentration transition. We also observed distinct SFG signal phase changes for water molecules associated with SDS layers at different SDS solution concentrations indicating that the orientation of bound water changed with SDS surface structure.

  8. of Several Organophosphorus Insecticide Metabolites

    Directory of Open Access Journals (Sweden)

    Russell L. Carr

    2015-01-01

    Full Text Available Paraoxonase (PON1 is a calcium dependent enzyme that is capable of hydrolyzing organophosphate anticholinesterases. PON1 activity is present in most mammals and previous research established that PON1 activity differs depending on the species. These studies mainly used the organophosphate substrate paraoxon, the active metabolite of the insecticide parathion. Using serum PON1 from different mammalian species, we compared the hydrolysis of paraoxon with the hydrolysis of the active metabolites (oxons of two additional organophosphorus insecticides, methyl parathion and chlorpyrifos. Paraoxon hydrolysis was greater than that of methyl paraoxon, but the level of activity between species displayed a similar pattern. Regardless of the species tested, the hydrolysis of chlorpyrifos-oxon was significantly greater than that of paraoxon or methyl paraoxon. These data indicate that chlorpyrifos-oxon is a better substrate for PON1 regardless of the species. The pattern of species differences in PON1 activity varied with the change in substrate to chlorpyrifos-oxon from paraoxon or methyl paraoxon. For example, the sex difference observed here and reported elsewhere in the literature for rat PON1 hydrolysis of paraoxon was not present when chlorpyrifos-oxon was the substrate.

  9. Electron beam patterning for writing of positively charged gold colloidal nanoparticles

    Science.gov (United States)

    Zafri, Hadar; Azougi, Jonathan; Girshevitz, Olga; Zalevsky, Zeev; Zitoun, David

    2018-02-01

    Synthesis at the nanoscale has progressed at a very fast pace during the last decades. The main challenge today lies in precise localization to achieve efficient nanofabrication of devices. In the present work, we report on a novel method for the patterning of gold metallic nanoparticles into nanostructures on a silicon-on-insulator (SOI) wafer. The fabrication makes use of relatively accessible equipment, a scanning electron microscope (SEM), and wet chemical synthesis. The electron beam implants electrons into the insulating material, which further anchors the positively charged Au nanoparticles by electrostatic attraction. The novel fabrication method was applied to several substrates useful in microelectronics to add plasmonic particles. The resolution and surface density of the deposition were tuned, respectively, by the electron energy (acceleration voltage) and the dose of electronic irradiation. We easily achieved the smallest written feature of 68 ± 18 nm on SOI, and the technique can be extended to any positively charged nanoparticles, while the resolution is in principle limited by the particle size distribution and the scattering of the electrons in the substrate. [Figure not available: see fulltext.

  10. Onset of turbulence induced by electron nonthermality in a complex plasma in presence of positively charged dust grains

    Directory of Open Access Journals (Sweden)

    Susmita Sarkar

    2018-03-01

    Full Text Available In this paper onset of turbulence has been detected from the study of non linear dust acoustic wave propagation in a complex plasma considering electrons nonthermal and equilibrium dust charge positive. Dust grains are charged by secondary electron emission process. Our analysis shows that increase in electron nonthermality makes the grain charging process faster by reducing the magnitude of the nonadiabaticity induced pseudo viscosity. Consequently nature of dust charge variation changes from nonadiabatic to adiabatic one. For further increase of electron nonthermality, this pseudo viscosity becomes negative and hence generates a turbulent grain charging behaviour. This turbulent grain charging phenomenon is exclusively the outcome of this nonlinear study which was not found in linear analysis.

  11. Lysophospholipase inhibition by organophosphorus toxicants

    International Nuclear Information System (INIS)

    Quistad, Gary B.; Casida, John E.

    2004-01-01

    Lysophospholipases (LysoPLAs) are a large family of enzymes for removing lysophospholipids from cell membranes. Potent inhibitors are needed to define the importance of LysoPLAs as targets for toxicants and potential therapeutics. This study considers organophosphorus (OP) inhibitors with emphasis on mouse brain total LysoPLA activity relative to the mipafox-sensitive neuropathy target esterase (NTE)-LysoPLA recently established as 17% of the total activity and important in the action of OP delayed toxicants. The most potent inhibitors of total LysoPLA in mouse brain are isopropyl dodecylphosphonofluoridate (also for LysoPLA of Vibrio bacteria), ethyl octylphosphonofluoridate (EOPF), and two alkyl-benzodioxaphosphorin 2-oxides (BDPOs)[(S)-octyl and dodecyl] (IC50 2-8 nM). OP inhibitors acting in vitro and in vivo differentiate a more sensitive portion but not a distinct NTE-LysoPLA compared with total LysoPLA activity. For 10 active inhibitors, NTE-LysoPLA is 17-fold more sensitive than total LysoPLA, but structure-activity comparisons give a good correlation (r 2 = 0.94) of IC50 values, suggesting active site structural similarity or identity. In mice 4 h after intraperitoneal treatment with discriminating doses, EOPF, tribufos (a plant defoliant), and dodecanesulfonyl fluoride inhibit 41-57% of the total brain LysoPLA and 85-99% of the NTE-LysoPLA activity. Total LysoPLA as well as NTE-LysoPLA is decreased in activity in Nte +/- -haploinsufficient mice compared to their Nte +/+ littermates. The lysolecithin level of spinal cord but not brain is elevated significantly following EOPF treatment (3 mg/kg), thereby focusing attention on localized rather than general alterations in lysophospholipid metabolism in OP-induced hyperactivity and toxicity

  12. Electrical Conductivity of Rocks and Dominant Charge Carriers. Part 1; Thermally Activated Positive Holes

    Science.gov (United States)

    Freund, Friedemann T.; Freund, Minoru M.

    2012-01-01

    The prevailing view in the geophysics community is that the electrical conductivity structure of the Earth's continental crust over the 5-35 km depth range can best be understood by assuming the presence of intergranular fluids and/or of intragranular carbon films. Based on single crystal studies of melt-grown MgO, magma-derived sanidine and anorthosite feldspars and upper mantle olivine, we present evidence for the presence of electronic charge carriers, which derive from peroxy defects that are introduced during cooling, under non-equilibrium conditions, through a redox conversion of pairs of solute hydroxyl arising from dissolution of H2O.The peroxy defects become thermally activated in a 2-step process, leading to the release of defect electrons in the oxygen anion sublattice. Known as positive holes and symbolized by h(dot), these electronic charge carriers are highly mobile. Chemically equivalent to O(-) in a matrix of O(2-) they are highly oxidizing. Being metastable they can exist in the matrix of minerals, which crystallized in highly reduced environments. The h(dot) are highly mobile. They appear to control the electrical conductivity of crustal rocks in much of the 5-35 km depth range.

  13. Design study of beam position monitors for measuring second-order moments of charged particle beams

    Science.gov (United States)

    Yanagida, Kenichi; Suzuki, Shinsuke; Hanaki, Hirofumi

    2012-01-01

    This paper presents a theoretical investigation on the multipole moments of charged particle beams in two-dimensional polar coordinates. The theoretical description of multipole moments is based on a single-particle system that is expanded to a multiparticle system by superposition, i.e., summing over all single-particle results. This paper also presents an analysis and design method for a beam position monitor (BPM) that detects higher-order (multipole) moments of a charged particle beam. To calculate the electric fields, a numerical analysis based on the finite difference method was created and carried out. Validity of the numerical analysis was proven by comparing the numerical with the analytical results for a BPM with circular cross section. Six-electrode BPMs with circular and elliptical cross sections were designed for the SPring-8 linac. The results of the numerical calculations show that the second-order moment can be detected for beam sizes ≧420μm (circular) and ≧550μm (elliptical).

  14. Design study of beam position monitors for measuring second-order moments of charged particle beams

    Directory of Open Access Journals (Sweden)

    Kenichi Yanagida

    2012-01-01

    Full Text Available This paper presents a theoretical investigation on the multipole moments of charged particle beams in two-dimensional polar coordinates. The theoretical description of multipole moments is based on a single-particle system that is expanded to a multiparticle system by superposition, i.e., summing over all single-particle results. This paper also presents an analysis and design method for a beam position monitor (BPM that detects higher-order (multipole moments of a charged particle beam. To calculate the electric fields, a numerical analysis based on the finite difference method was created and carried out. Validity of the numerical analysis was proven by comparing the numerical with the analytical results for a BPM with circular cross section. Six-electrode BPMs with circular and elliptical cross sections were designed for the SPring-8 linac. The results of the numerical calculations show that the second-order moment can be detected for beam sizes ≧420  μm (circular and ≧550  μm (elliptical.

  15. Enhanced biomimic bactericidal surfaces by coating with positively-charged ZIF nano-dagger arrays.

    Science.gov (United States)

    Yuan, Yuan; Zhang, Yugen

    2017-10-01

    Cicada wing surfaces are covered with dense patterns of nano-pillar structure that prevent bacterial growth by rupturing adhered microbial cells. To mimic the natural nano-pillar structure, we developed a general and simple method to grow metal organic framework (MOF) nano-dagger arrays on a wide range of surfaces. These nano-daggers possess high bactericidal activity, with log reduction >7 for Escherichia coli and Staphylococcus aureus. It was hypothesized that the positively-charged ZIF-L nano-dagger surfaces enhance bacterial cell adhesion, facilitating selective and efficient bacteria killing by the rigid and sharp nano-dagger tips. This research provides a safe and clean antimicrobial surface technology which does not require external chemicals and will not cause drug resistance. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Positively Charged Nanostructured Lipid Carriers and Their Effect on the Dissolution of Poorly Soluble Drugs

    Directory of Open Access Journals (Sweden)

    Kyeong-Ok Choi

    2016-05-01

    Full Text Available The objective of this study is to develop suitable formulations to improve the dissolution rate of poorly water soluble drugs. We selected lipid-based formulation as a drug carrier and modified the surface using positively charged chitosan derivative (HTCC to increase its water solubility and bioavailability. Chitosan and HTCC-coated lipid particles had higher zeta-potential values than uncoated one over the whole pH ranges and improved encapsulation efficiency. In vitro drug release showed that all NLC formulations showed higher in vitro release efficiency than drug particle at pH 7.4. Furthermore, NLC formulation prepared with chitosan or HTCC represented good sustained release property. The results indicate that chitosan and HTCC can be excellent formulating excipients of lipid-based delivery carrier for improving poorly water soluble drug delivery.

  17. Positively Charged Nanostructured Lipid Carriers and Their Effect on the Dissolution of Poorly Soluble Drugs.

    Science.gov (United States)

    Choi, Kyeong-Ok; Choe, Jaehyeog; Suh, Seokjin; Ko, Sanghoon

    2016-05-20

    The objective of this study is to develop suitable formulations to improve the dissolution rate of poorly water soluble drugs. We selected lipid-based formulation as a drug carrier and modified the surface using positively charged chitosan derivative (HTCC) to increase its water solubility and bioavailability. Chitosan and HTCC-coated lipid particles had higher zeta-potential values than uncoated one over the whole pH ranges and improved encapsulation efficiency. In vitro drug release showed that all NLC formulations showed higher in vitro release efficiency than drug particle at pH 7.4. Furthermore, NLC formulation prepared with chitosan or HTCC represented good sustained release property. The results indicate that chitosan and HTCC can be excellent formulating excipients of lipid-based delivery carrier for improving poorly water soluble drug delivery.

  18. Position dependence of charge collection in prototype sensors for the CMS pixel detector

    CERN Document Server

    Rohe, Tilman; Chiochia, Vincenzo; Cremaldi, Lucien M; Cucciarelli, Susanna; Dorokhov, Andrei; Konecki, Marcin; Prokofiev, Kirill; Regenfus, Christian; Sanders, David A; Son Seung Hee; Speer, Thomas; Swartz, Morris

    2004-01-01

    This paper reports on the sensor R&D activity for the CMS pixel detector. Devices featuring several design and technology options have been irradiated up to a proton fluence1 of 1 multiplied by 10**1**5 n //e//q/cm**2 at the CERN PS. Afterward, they were bump bonded to unirradiated readout chips and tested using high energy pions in the H2 beam line of the CERN SPS. The readout chip allows a nonzero suppressed full analogue readout and therefore a good characterization of the sensors in terms of noise and charge collection properties. The position dependence of signal is presented and the differences between the two sensor options are discussed. 20 Refs.

  19. Efficacious Oxime for Organophosphorus Poisoning: A Minireview

    African Journals Online (AJOL)

    Erah

    Abstract. Oximes are well known as acetylcholinesterase reactivators and are used in ... activity against structurally different kinds of organophosphorus ... serious threat with regard to occupational .... choose an oxime for unknown OPC exposure. Secondly, there is a lack of .... oximes, and hence cannot pass the blood.

  20. A retrospective analysis of acute organophosphorus poisoning ...

    African Journals Online (AJOL)

    A retrospective analysis of acute organophosphorus poisoning cases admitted to the tertiary care teaching hospital in South India. ... Young adult males were more commonly involved than females (M:F 2.5:1). The mean age of the patients was 28 years (range 2-72 years, SD ± 14.3 years). Mean time to receive treatment ...

  1. A retrospective analysis of acute organophosphorus poisoning ...

    African Journals Online (AJOL)

    organophosphorus (OP) poisoning cases in a tertiary care hospital. Materials and ... In a pre-structured proforma, data regarding age, sex, time elapsed after intake, circumstances of poisoning, duration of hospitalization ... responsible for majority of self-attempted deaths ... cleansed with water at the time of admission.

  2. Determination of selected organophosphorus pesticides using GC ...

    African Journals Online (AJOL)

    A reproducible analytical method utilising GC-MS is presented for the analysis of thirteen organophosphorus insecticides (OPs) often found in environmental aqueous samples. Extraction of filtered river and canal water (100 mL), fortified with the OPs, was conducted using solid-phase extraction and eluted with a variety of ...

  3. Efficacious Oxime for Organophosphorus Poisoning: A Minireview ...

    African Journals Online (AJOL)

    Oximes are well known as acetylcholinesterase reactivators and are used in organophosphorus poisoning to reactivate inhibited acetylcholinesterase. Therapeutically available oximes, namely, pralidoxime (2-PAM), obidoxime, trimedoxime and Hagedorn oxime (HI-6), have no broad-spectrum activity against structurally ...

  4. Think positive : phase separation enables a positively charged additive to induce dramatic changes in calcium carbonate morphology

    NARCIS (Netherlands)

    Cantaert, B.; Kim, Y.; Ludwig, H.; Nudelman, F.; Sommerdijk, N.A.J.M.; Meldrum, F.C.

    2012-01-01

    Soluble macromolecules are essential to Nature's control over biomineral formation. Following early studies where macromolecules rich in aspartic and glutamic acid were extracted from nacre, research has focused on the use of negatively charged additives to control calcium carbonate precipitation.

  5. Studies of the pulse charge of lead-acid batteries for PV applications. Part I. Factors influencing the mechanism of the pulse charge of the positive plate

    Energy Technology Data Exchange (ETDEWEB)

    Kirchev, A.; Perrin, M.; Lemaire, E.; Karoui, F.; Mattera, F. [Commissariat de l' Energie Atomique, Institut National de l' Energie Solaire, INES-RDI, Parc Technologique de Savoie Technolac, 50 Avenue du Lac Leman, 73377 Le Bourget du Lac Cedex (France)

    2008-02-15

    The mechanism of the positive plate charge in pulse regime was studied in model lead-acid cells with one positive and two negative plates (8 Ah each) and Ag/Ag{sub 2}SO{sub 4} reference electrodes. The results showed that the evolution of the electrode potential is much slower on the positive plate than on the negative plate. Regardless of this fact, the calculated capacitive current of charge and self-discharge of the electrochemical double layer (EDL) during the 'ON' and 'OFF' half-periods of the pulse current square waves is comparable with the charge current amplitude. The result is due to the high values of the EDL on the surface of the lead dioxide active material. The influence of different factors like state of charge, state of health, pulse frequency, current amplitude and open circuit stay before the polarization was discussed. The previously determined optimal frequency of 1 Hz was associated with a maximum in the average double layer current on frequency dependence. The average double layer current is also maximal at SOC between 75 and 100%. The exchange of the constant current polarization with pulse polarization does not change substantially the mechanism and the overvoltage of the oxygen evolution reaction on the positive plate. The mechanism of the self-discharge of the EDL was also estimated analyzing long-time PPP transients (up to 2 h). It was found that when the PPP is lower than 1.2 V the preferred mechanism of EDL self-discharge is by coupling with the lead sulphate oxidation reaction. At higher values of PPP the EDL self-discharge happens via oxygen evolution. The high faradic efficiency of the pulse charge is due to the chemical oxidation of the Pb(II) ions by the O atoms and OH radicals formed at the oxygen evolution both during the 'ON' and 'OFF' periods. (author)

  6. Position statement on ethics, equipoise and research on charged particle radiation therapy.

    Science.gov (United States)

    Sheehan, Mark; Timlin, Claire; Peach, Ken; Binik, Ariella; Puthenparampil, Wilson; Lodge, Mark; Kehoe, Sean; Brada, Michael; Burnet, Neil; Clarke, Steve; Crellin, Adrian; Dunn, Michael; Fossati, Piero; Harris, Steve; Hocken, Michael; Hope, Tony; Ives, Jonathan; Kamada, Tadashi; London, Alex John; Miller, Robert; Parker, Michael; Pijls-Johannesma, Madelon; Savulescu, Julian; Short, Susan; Skene, Loane; Tsujii, Hirohiko; Tuan, Jeffrey; Weijer, Charles

    2014-08-01

    The use of charged-particle radiation therapy (CPRT) is an increasingly important development in the treatment of cancer. One of the most pressing controversies about the use of this technology is whether randomised controlled trials are required before this form of treatment can be considered to be the treatment of choice for a wide range of indications. Equipoise is the key ethical concept in determining which research studies are justified. However, there is a good deal of disagreement about how this concept is best understood and applied in the specific case of CPRT. This report is a position statement on these controversies that arises out of a workshop held at Wolfson College, Oxford in August 2011. The workshop brought together international leaders in the relevant fields (radiation oncology, medical physics, radiobiology, research ethics and methodology), including proponents on both sides of the debate, in order to make significant progress on the ethical issues associated with CPRT research. This position statement provides an ethical platform for future research and should enable further work to be done in developing international coordinated programmes of research. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  7. Positively versus negatively charged moral emotion expectancies in adolescence: the role of situational context and the developing moral self.

    Science.gov (United States)

    Krettenauer, Tobias; Johnston, Megan

    2011-09-01

    The study analyses adolescents' positively charged versus negatively charged moral emotion expectancies. Two hundred and five students (M= 14.83 years, SD= 2.21) participated in an interview depicting various situations in which a moral norm was either regarded or transgressed. Emotion expectancies were assessed for specific emotions (pride, guilt) as well as for overall strength and valence. In addition, self-importance of moral values was measured by a questionnaire. Results revealed that positively charged emotion expectancies were more pronounced in contexts of prosocial action than in the context of moral transgressions, whereas the opposite was true for negatively charged emotions. At the same time, expectations of guilt and pride were substantially related to the self-importance of moral values. ©2010 The British Psychological Society.

  8. Biochemical Markers for Exposure to Low Doses of Organophosphorus Insecticides

    National Research Council Canada - National Science Library

    Lockridge, Oksana

    2003-01-01

    Though acetylcholinesterase is the primary target of organophosphorus toxicants, our finding that acetylcholinesterase knockout mice are supersensitive to the lethal effects of VX, DFP, chlorpyrifos...

  9. Biochemical Markers for Exposure to Low Doses of Organophosphorus Insecticides

    National Research Council Canada - National Science Library

    Lockridge, Oksana

    2004-01-01

    Though acetylcholinesterase is the primary target of organophosphorus toxicants, our finding that acetylcholinesterase knockout mice are supersensitive to the lethal effects of VX, DFP, chlorpyrifos...

  10. Biochemical Markers for Exposure to Low Doses of Organophosphorus Insecticides

    National Research Council Canada - National Science Library

    Lockridge, Oksana

    2002-01-01

    Though acetyicholinesterase is the primary target of organophosphorus toxicants, our finding that acetyicholinesterase knockout mice are supersensitive to the lethal effects of VX, DFP, chlorpyrifos...

  11. Two-dimensional potential and charge distributions of positive surface streamer

    International Nuclear Information System (INIS)

    Tanaka, Daiki; Matsuoka, Shigeyasu; Kumada, Akiko; Hidaka, Kunihiko

    2009-01-01

    Information on the potential and the field profile along a surface discharge is required for quantitatively discussing and clarifying the propagation mechanism. The sensing technique with a Pockels crystal has been developed for directly measuring the potential and electric field distribution on a dielectric material. In this paper, the Pockels sensing system consists of a pulse laser and a CCD camera for measuring the instantaneous two-dimensional potential distribution on a 25.4 mm square area with a 50 μm sampling pitch. The temporal resolution is 3.2 ns which is determined by the pulse width of the laser emission. The transient change in the potential distribution of a positive surface streamer propagating in atmospheric air is measured with this system. The electric field and the charge distributions are also calculated from the measured potential profile. The propagating direction component of the electric field near the tip of the propagating streamer reaches 3 kV mm -1 . When the streamer stops, the potential distribution along a streamer forms an almost linear profile with the distance from the electrode, and its gradient is about 0.5 kV mm -1 .

  12. Positively charged gold nanoparticles capped with folate quaternary chitosan: Synthesis, cytotoxicity, and uptake by cancer cells.

    Science.gov (United States)

    Yen, Hui-Ju; Young, Yen-An; Tsai, Tsung-Neng; Cheng, Kuang-Ming; Chen, Xin-An; Chen, Ying-Chuan; Chen, Cheng-Cheung; Young, Jenn-Jong; Hong, Po-da

    2018-03-01

    In this study, we synthesized various quaternary chitosan derivatives and used them to stabilize gold nanoparticles (AuNPs). These chitosan derivatives comprised N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC), folate-HTCC, galactosyl-HTCC, and their fluorescein isothiocyanate-conjugated derivatives. Various positively surface-charged AuNPs were prepared under alkaline conditions using glucose as a reducing agent in the presence of the HTCC derivatives (HTCCs). The effects of the concentration of NaOH, glucose, and HTCCs on the particles size, zeta potential, and stability were studied in detail. Cell cycle assays verify that none of the HTCCs or HTCCs-AuNPs was cytotoxic to human umbilical vein endothelial cells. Flow cytometry analysis showed that the folate HTCC-AuNPs were internalized in Caco-2, HepG2, and HeLa cancer cells to a significantly greater extent than AuNPs without folate. But, galactosyl HTCC-AuNPs only showed high cell uptake by HepG2 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The role of NH2-terminal positive charges in the activity of inward rectifier KATP channels.

    Science.gov (United States)

    Cukras, C A; Jeliazkova, I; Nichols, C G

    2002-09-01

    Approximately half of the NH(2) terminus of inward rectifier (Kir) channels can be deleted without significant change in channel function, but activity is lost when more than approximately 30 conserved residues before the first membrane spanning domain (M1) are removed. Systematic replacement of the positive charges in the NH(2) terminus of Kir6.2 with alanine reveals several residues that affect channel function when neutralized. Certain mutations (R4A, R5A, R16A, R27A, R39A, K47A, R50A, R54A, K67A) change open probability, whereas an overlapping set of mutants (R16A, R27A, K39A, K47A, R50A, R54A, K67A) change ATP sensitivity. Further analysis of the latter set differentiates mutations that alter ATP sensitivity as a consequence of altered open state stability (R16A, K39A, K67A) from those that may affect ATP binding directly (K47A, R50A, R54A). The data help to define the structural determinants of Kir channel function, and suggest possible structural motifs within the NH(2) terminus, as well as the relationship of the NH(2) terminus with the extended cytoplasmic COOH terminus of the channel.

  14. Osteoblasts with impaired spreading capacity benefit from the positive charges of plasma polymerised allylamine

    Directory of Open Access Journals (Sweden)

    F Kunz

    2015-03-01

    Full Text Available Bone diseases such as osteoporosis, osteoarthritis and rheumatoid arthritis, impinge on the performance of orthopaedic implants by impairing bone regeneration. For this reason, the development of effective surface modifications supporting the ingrowth of implants in morbid bone tissue is essential. Our study is designed to elucidate if cells with restricted cell-function limiting adhesion processes benefit from plasma polymer deposition on titanium. We used the actin filament disrupting agent cytochalasin D (CD as an experimental model for cells with impaired actin cytoskeleton. Indeed, the cell’s capacity to adhere and spread was drastically reduced due to shortened actin filaments and vinculin contacts that were smaller. The coating of titanium with a positively charged nanolayer of plasma polymerised allylamine (PPAAm abrogated these disadvantages in cell adhesion and the CD-treated osteoblasts were able to spread significantly. Interestingly, PPAAm increased spreading by causing enhanced vinculin number and contact length, but without significantly reorganising actin filaments. PPAAm with the monomer allylamine was deposited in a microwave-excited low-pressure plasma-processing reactor. Cell physiology was monitored by flow cytometry and confocal laser scanning microscopy, and the length and number of actin filaments was quantified by mathematical image processing. We showed that biomaterial surface modification with PPAAm could be beneficial even for osteoblasts with impaired cytoskeleton components. These insights into in vitro conditions may be used for the evaluation of future strategies to design implants for morbid bone tissue.

  15. Different approaches to acute organophosphorus poison treatment.

    Science.gov (United States)

    Nurulain, Syed Muhammad

    2012-07-01

    Organophosphorus compounds (OPCs) have a wide variety of applications and are a serious threat for self-poisoning, unintentional misuse, terrorist attack, occupational hazard and warfare attack. The present standard treatment has been reported to be unsatisfactory. Many novel approaches are being used and tested for acute organophosphorus (OP) poison treatment. The bioscavenger concept captured high attention among the scientific community during the last few decades. Other approaches like alkalinisation of blood plasma/serum and use of weak inhibitors against strong inhibitors, though it showed promising results, did not get such wide attention. The introduction of a novel broad-spectrum oxime has also been in focus. In this mini-review, an update of the overview of four different approaches has been discussed. The standard therapy that is atropine+oxime+benzodiazepine along with supportive measures will continue to be the best option with only the replacement of a single oxime to improve its broad-spectrum efficacy.

  16. Management of acute organophosphorus pesticide poisoning.

    Science.gov (United States)

    Eddleston, Michael; Buckley, Nick A; Eyer, Peter; Dawson, Andrew H

    2008-02-16

    Organophosphorus pesticide self-poisoning is an important clinical problem in rural regions of the developing world, and kills an estimated 200,000 people every year. Unintentional poisoning kills far fewer people but is a problem in places where highly toxic organophosphorus pesticides are available. Medical management is difficult, with case fatality generally more than 15%. We describe the limited evidence that can guide therapy and the factors that should be considered when designing further clinical studies. 50 years after first use, we still do not know how the core treatments--atropine, oximes, and diazepam--should best be given. Important constraints in the collection of useful data have included the late recognition of great variability in activity and action of the individual pesticides, and the care needed cholinesterase assays for results to be comparable between studies. However, consensus suggests that early resuscitation with atropine, oxygen, respiratory support, and fluids is needed to improve oxygen delivery to tissues. The role of oximes is not completely clear; they might benefit only patients poisoned by specific pesticides or patients with moderate poisoning. Small studies suggest benefit from new treatments such as magnesium sulphate, but much larger trials are needed. Gastric lavage could have a role but should only be undertaken once the patient is stable. Randomised controlled trials are underway in rural Asia to assess the effectiveness of these therapies. However, some organophosphorus pesticides might prove very difficult to treat with current therapies, such that bans on particular pesticides could be the only method to substantially reduce the case fatality after poisoning. Improved medical management of organophosphorus poisoning should result in a reduction in worldwide deaths from suicide.

  17. Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

    International Nuclear Information System (INIS)

    Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

    2017-01-01

    Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20–25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30–60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p + implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO 2 interface charge densities ( Q f ) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p + implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Q f , that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

  18. Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

    Science.gov (United States)

    Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

    2017-09-01

    Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20-25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30-60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p+ implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO2 interface charge densities (Qf) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p+ implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Qf, that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

  19. Separation analysis of macrolide antibiotics with good performance on a positively charged C18HCE column.

    Science.gov (United States)

    Wei, Jie; Shen, Aijin; Yan, Jingyu; Jin, Gaowa; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

    2016-03-01

    The separation of basic macrolide antibiotics suffers from peak tailing and poor efficiency on traditional silica-based reversed-phase liquid chromatography columns. In this work, a C18HCE column with positively charged surface was applied to the separation of macrolides. Compared with an Acquity BEH C18 column, the C18HCE column exhibited superior performance in the aspect of peak shape and separation efficiency. The screening of mobile phase additives including formic acid, acetic acid and ammonium formate indicated that formic acid was preferable for providing symmetrical peak shapes. Moreover, the influence of formic acid content was investigated. Analysis speed and mass spectrometry compatibility were also taken into account when optimizing the separation conditions for liquid chromatography coupled with tandem mass spectrometry. The developed method was successfully utilized for the determination of macrolide residues in a honey sample. Azithromycin was chosen as the internal standard for the quantitation of spiramycin and tilmicosin, while roxithromycin was used for erythromycin, tylosin, clarithromycin, josamycin and acetylisovaleryltylosin. Good correlation coefficients (r(2) > 0.9938) for all macrolides were obtained. The intra-day and inter-day recoveries were 73.7-134.7% and 80.7-119.7% with relative standard deviations of 2.5-8.0% and 3.9-16.1%, respectively. Outstanding sensitivity with limits of quantitation (S/N ≥ 10) of 0.02-1 μg/kg and limits of detection (S/N ≥ 3) of 0.01-0.5 μg/kg were achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Quantum size correction to the work function and the centroid of excess charge in positively ionized simple metal clusters

    Directory of Open Access Journals (Sweden)

    M. Payami

    2003-12-01

    Full Text Available  In this work, we have shown the important role of the finite-size correction to the work function in predicting the correct position of the centroid of excess charge in positively charged simple metal clusters with different values . For this purpose, firstly we have calculated the self-consistent Kohn-Sham energies of neutral and singly-ionized clusters with sizes in the framework of local spin-density approximation and stabilized jellium model (SJM as well as simple jellium model (JM with rigid jellium. Secondly, we have fitted our results to the asymptotic ionization formulas both with and without the size correction to the work function. The results of fittings show that the formula containing the size correction predict a correct position of the centroid inside the jellium while the other predicts a false position, outside the jellium sphere.

  1. Quantum size correction to the work function and centroid of excess charge in positively ionized simple metal clusters

    International Nuclear Information System (INIS)

    Payami, M.

    2004-01-01

    In this work, we have shown the important role of the finite-size correction to the work function in predicting the correct position of the centroid of excess charge in positively charged simple metal clusters with different r s values (2≤ r s ≥ 7). For this purpose, firstly we have calculated the self-consistent Kohn-Sham energies of neutral and singly-ionized clusters with sizes 2≤ N ≥100 in the framework of local spin-density approximation and stabilized jellium model as well as simple jellium model with rigid jellium. Secondly, we have fitted our results to the asymptotic ionization formulas both with and without the size correction to the work function. The results of fittings show that the formula containing the size correction predict a correct position of the centroid inside the jellium while the other predicts a false position, outside the jellium sphere

  2. Charge dividing mechanism on resistive electrode in position-sensitive detectors

    International Nuclear Information System (INIS)

    Radeka, V.; Rehak, P.

    1978-10-01

    A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistancies and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2π (L/C) 1 / 2 , where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line

  3. Long-Term Charge/Discharge Cycling Stability of MnO2 Aqueous Supercapacitor under Positive Polarization

    KAUST Repository

    Ataherian, Fatemeh; Wu, Nae-Lih

    2011-01-01

    The long-term charge/discharge cycling stability of MnO 2 electrode under positive polarization in aqueous KCl electrolyte has been studied over different potential windows spanning from the open circuit potential to varied higher-end potential

  4. Analysis of organophosphorus pesticides using FT-NMR

    International Nuclear Information System (INIS)

    Miyata, Yoshihiko; Takahashi, Yoshikazu; Ando, Hiroaki

    1988-01-01

    A rapid and highly selective method of the identification of 23 kinds of organophosphorus pesticides was develop by using 31 P FT-NMR with 1 H complete decoupling method. Chemical shifts referenced by 85 % H 3 PO 4 were within -4 to 100 ppm, and there was no overlapping among the organophosphorus pesticides used in this experiment. (author)

  5. Charge Spreading and Position Sensitivity in a Segmented Planar Germanium Detector (Preprint)

    National Research Council Canada - National Science Library

    Kroeger, R. A; Gehrels, N; Johnson, W. N; Kurfess, J. D; Phlips, B. P; Tueller, J

    1998-01-01

    The size of the charge cloud collected in a segmented germanium detector is limited by the size of the initial cloud, uniformity of the electric field, and the diffusion of electrons and holes through the detector...

  6. The regiochemical distribution of positive charges along cholesterol polyamine carbamates plays significant roles in modulating DNA binding affinity and lipofection.

    Science.gov (United States)

    Geall, A J; Eaton, M A; Baker, T; Catterall, C; Blagbrough, I S

    1999-10-15

    We have quantified the effects of the regiochemical distribution of positive charges along the polyamine moiety in lipopolyamines for DNA molecular recognition. High affinity binding leads to charge neutralisation, DNA condensation and ultimately to lipofection. Binding affinities for calf thymus DNA were determined using an ethidium bromide displacement assay and condensation was detected by changes in turbidity using light scattering. The in vitro transfection competence of cholesterol polyamine carbamates was measured in CHO cells. In the design of DNA condensing and transfecting agents for non-viral gene therapy, the interrelationship of ammonium ions, not just their number, must be considered.

  7. On a possibility of creation of positive space charge cloud in a system with magnetic insulation of electrons

    International Nuclear Information System (INIS)

    Goncharov, A.A.; Dobrovol'skii, A.M.; Dunets, S.P.; Evsyukov, A.N.; Protsenko, I.M.

    2009-01-01

    We describe a new approach for creation an effective, low-cost, low-maintenance axially symmetric plasma optical tools for focusing and manipulating high-current beams of negatively charged particles, electrons and negative ions. This approach is based on fundamental plasma optical concept of magnetic insulation of electrons and non-magnetized positive ions providing creation of controlled uncompensated cloud of the space charge. The axially symmetric electrostatic plasma optical lens is well-known and well developed tool where this concept is used successfully. This provides control and focusing high-current positive ion beams in wide range of parameters. Here for the first time we present optimistic experimental results describing the application of an idea of magnetic insulation of electrons for generation of the stable cloud of positive space charge by focusing onto axis the converging stream of heavy ions produced by circular accelerator with closed electron drift. The estimations of a maximal concentration of uncompensated cloud of positive ions are also made

  8. Effect of scanning in the supine and prone positions on dilation of air-charged colon in CTVC

    International Nuclear Information System (INIS)

    Ye Jing; Chen Junkun; Zhang Zongjun; Wang Junpeng; Gao Dazhi

    2003-01-01

    Objective: To evaluate the effect of scanning in the supine and prone positions on dilation of air-charged colon in CT virtual colonoscopy (CTVC). Methods: Thirty cases underwent CTVC scanning in both the supine and prone positions immediately before colonoscopy, and the dilation of each intestine was graded. The differences of colon dilation in different positions were compared. Results: In supine and prone position, there were 26 (17.3%) and 22 (14.7%) insufficient dilating colon segments, respectively, and only 5 (3.3%) insufficient dilating colon segments in double positions. 15(50.0%) and 13(43.3%) colons dilated insufficiently in supine and prone position, respectively, and decreased to 5 (16.7%) in double positions. The dilation of rectum, sigmoid colon, and transverse colon had significant difference in different positions. Conclusion: When performing CTVC, it is highly necessary to scan in both the supine and prone positions in order to ensure the sufficient dilation of colon. In supine position, the dilation of transverse colon is better, while the dilation of rectum and sigmoid colon in prone position is superior to that in supine position

  9. Development and use of thin film composite based positively charged nanofiltration membranes in separation of aqueous streams and nuclear effluents

    International Nuclear Information System (INIS)

    Dey, T.K.; Bindal, R.C.; Prabhakar, S.; Tewari, P.K.

    2010-01-01

    A new, positively charged, thin film composite (TFC) type nanofiltration membrane has been developed and studied for its use in various aqueous stream separations. The membrane, containing fixed quaternary ammonium moieties, was developed by insitu interfacial polymerization of a functionalized amine (polyethyleneimine) and terephthaloyl chloride on a suitable base membrane. The nature of the charge on the membrane was established by ATR FT IR spectroscopy and was estimated by determination of its ion exchange capacity. The membrane was tested for its performance in single solute feed systems containing salts of various combinations of univalent and bivalent ions (NaCl, Na 2 SO 4 , CaCl 2 and MgSO 4 ) in test cell as well as in 2512 spiral modules. The membrane gave differential separation profile for these solutes with high rejection for CaCl 2 and low rejection for Na 2 SO 4 due to positive charge on the membrane and the type of charge constituting the salts. The membrane was also used for separation of simulated effluent solution containing uranyl nitrate in combination with ammonium nitrate which is a common effluent generated in nuclear industry. Here also the membrane gave differential separation profile for uranyl nitrate and ammonium nitrate in their mixture by concentrating the former salt and passing the later. This helped separation of these two solutes in the mixture into two different streams. (author)

  10. Lithium position and occupancy fluctuations in a cathode during charge/discharge cycling of lithium-ion battery

    International Nuclear Information System (INIS)

    Sharma, N.; Yu, D.; Zhu, Y.; Wu, Y.; Peterson, V. K.

    2012-01-01

    Lithium-ion batteries are undergoing rapid development to meet the energy demands of the transportation and renewable energy-generation sectors. The capacity of a lithium-ion battery is dependent on the amount of lithium that can be reversibly incorporated into the cathode. Neutron diffraction provides greater sensitivity towards lithium relative to other diffraction techniques. In conjunction with the penetration depth afforded by neutron diffraction, the information concerning lithium gained in a neutron diffraction study allows commercial lithium-ion batteries to be explored with respect to the lithium content in the whole cathode. Furthermore, neutron diffraction instruments featuring area detectors that allow relatively fast acquisitions enable perturbations of lithium location and occupancy in the cathode during charge/discharge cycling to be determined in real time. Here, we present the time, current, and temperature dependent lithium transfer occurring within a cathode functioning under conventional charge-discharge cycling. The lithium location and content, oxygen positional parameter, and lattice parameter of the Li 1+y Mn 2 0 4 cathode are measured and linked to the battery's charge/discharge characteristics (performance). We determine that the lithium-transfer mechanism involves two crystallographic sites, and that the mechanism differs between discharge and charge, explaining the relative ease of discharging (compared with charging) this material. Furthermore, we find that the rate of change of the lattice is faster on charging than discharging, and is dependent on the lithium insertion/ extraction processes (e.g. dependent on how the site occupancies evolve). Using in situ neutron diffraction data the atomic-scale understanding of cathode functionality is revealed, representing detailed information that can be used to direct improvements in battery performance at both the practical and fundamental level.

  11. Chlorination of organophosphorus pesticides in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Acero, Juan L. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: jlacero@unex.es; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 {sup o}C and pH 7 were determined to be 110.9, 0.004 and 191.6 M{sup -1} s{sup -1} for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L{sup -1} was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  12. Chlorination of organophosphorus pesticides in natural waters

    International Nuclear Information System (INIS)

    Acero, Juan L.; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel

    2008-01-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 o C and pH 7 were determined to be 110.9, 0.004 and 191.6 M -1 s -1 for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L -1 was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety

  13. Effect of positively charged particles on sputtering damage of organic electro-luminescent diodes with Mg:Ag alloy electrodes fabricated by facing target sputtering

    Directory of Open Access Journals (Sweden)

    Kouji Suemori

    2017-04-01

    Full Text Available We investigated the influence of the positively charged particles generated during sputtering on the performances of organic light-emitting diodes (OLEDs with Mg:Ag alloy electrodes fabricated by sputtering. The number of positively charged particles increased by several orders of magnitude when the target current was increased from 0.1 A to 2.5 A. When a high target current was used, many positively charged particles with energies higher than the bond energy of single C–C bonds, which are typically found in organic molecules, were generated. In this situation, we observed serious OLED performance degradation. On the other hand, when a low target current was used, OLED performance degradation was not observed when the number of positively charged particles colliding with the organic underlayer increased. We concluded that sputtering damage caused by positively charged particles can be avoided by using a low target current.

  14. Effect of position and momentum constraints on charge distribution in heavy-ion collisions

    International Nuclear Information System (INIS)

    Rajni; Kumar, Suneel

    2012-01-01

    The rich phenomenology of multifragmentation has been widely explored after two decades of its discovery. It has been experimentally shown that in one single heavy ion collision many intermediate mass fragments (IMFs) are produced, where IMFs are defined as fragments with 5 ≤ A ≤ A tot /6. In the earlier literature, the multifragmentation was studied by Jakobsson et al. who measured the charge particle distribution along with their kinetic energy spectra in 16 O/ 36 Ar induced reaction between 25 and 200 MeV/nucleon representing the various phenomena in heavy ion collisions

  15. Colorimetric method for determination of bisphenol A based on aptamer-mediated aggregation of positively charged gold nanoparticles

    International Nuclear Information System (INIS)

    Xu, Jingyue; Li, Ying; Bie, Jiaxin; Guo, Jiajia; Luo, Yeli; Shen, Fei; Sun, Chunyan; Jiang, Wei

    2015-01-01

    A sensitive, specific and rapid colorimetric aptasensor for the determination of the plasticizer bisphenol A (BPA) was developed. It is based on the use of gold nanoparticles (AuNPs) that are positively charged due to the modification with cysteamine which is cationic at near-neutral pH values. If aptamers are added to such AuNPs, aggregation occurs due to electrostatic interactions between the negatively-charged aptamers and the positively-charged AuNPs. This results in a color change of the AuNPs from red to blue. If a sample containing BPA is added to the anti-BPA aptamers, the anti-BPA aptamers undergo folding via an induced-fit binding mechanism. This is accompanied by a conformational change, which prevents the aptamer-induced aggregation and color change of AuNPs. The effect was exploited to design a colorimetric assay for BPA. Under optimum conditions, the absorbance ratio of A 527 /A 680 is linearly proportional to the BPA concentration in the range from 35 to 140 ng∙mL −1 , with a detection limit of 0.11 ng∙mL −1 . The method has been successfully applied to the determination of BPA in spiked tap water and gave recoveries between 91 and 106 %. Data were in full accordance with results obtained from HPLC. This assay is selective, easily performed, and in our perception represents a promising alternative to existing methods for rapid quantification of BPA. (author)

  16. Elaboration of Stable and Antibody Functionalized Positively Charged Colloids by Polyelectrolyte Complexation between Chitosan and Hyaluronic Acid

    Directory of Open Access Journals (Sweden)

    Ramona C. Polexe

    2013-07-01

    Full Text Available In this study, we describe the elaboration of multifunctional positively charged polyelectrolyte complex (PEC nanoparticles, designed to be stable at physiological salt concentration and pH, for effective targeted delivery. These nanoparticles were obtained by charge neutralization between chitosan (CS as polycation and hyaluronic acid (HA as polyanion. We showed that the course of the complexation process and the physico-chemical properties of the resulting colloids were impacted by (i internal parameters such as the Degree of Acetylation (DA, i.e., the molar ration of acetyl glucosamine residues and molar mass of CS, the HA molar mass and (ii external parameters like the charge mixing ratio and the polymer concentrations. As a result, nonstoichiometric colloidal PECs were obtained in water or PBS (pH 7.4 and remained stable over one month. The polymer interactions were characterized by thermal analysis (DSC and TGA and the morphology was studied by scanning electron microscopy. A model antibody, anti-ovalbumine (OVA immunoglobulin A (IgA was sorbed on the particle surface in water and PBS quantitatively in 4 h. The CS-HA/IgA nanoparticles average size was between 425–665 nm with a positive zeta potential. These results pointed out that CS-HA can be effective carriers for use in targeted drug delivery.

  17. Treatment Strategies for the NMDA Component of Organophosphorus Convulsions

    National Research Council Canada - National Science Library

    Peterson, Steven

    2003-01-01

    ...) induced status epilepticus (SE) used here as a model of organophosphorus nerve agents. The nonbarbiturate anesthetic propofol was found to induce significant anticonvulsant and neuroprotectant effects in Li-pilo SE...

  18. The Effect of Charge at the Surface of Silver Nanoparticles on Antimicrobial Activity against Gram-Positive and Gram-Negative Bacteria: A Preliminary Study

    International Nuclear Information System (INIS)

    Abbaszadegan, A.; Ghahramani, Y.; Nabavizadeh, M.; Gholami, A.; Hemmateenejad, I.; Dorostkar, S.; Sharghi, H.

    2014-01-01

    The bactericidal efficiency of various positively and negatively charged silver nanoparticles has been extensively evaluated in literature, but there is no report on efficacy of neutrally charged silver nanoparticles. The goal of this study is to evaluate the role of electrical charge at the surface of silver nanoparticles on antibacterial activity against a panel of microorganisms. Three different silver nanoparticles were synthesized by different methods, providing three different electrical surface charges (positive, neutral, and negative). The antibacterial activity of these nanoparticles was tested against gram-positive (i.e., Staphylococcus aureus, Streptococcus mutans, and Streptococcus pyogenes) and gram-negative (i.e., Escherichia coli and Proteus vulgaris) bacteria. Well diffusion and micro-dilution tests were used to evaluate the bactericidal activity of the nanoparticles. According to the obtained results, the positively-charged silver nanoparticles showed the highest bactericidal activity against all microorganisms tested. The negatively charged silver nanoparticles had the least and the neutral nanoparticles had intermediate antibacterial activity. The most resistant bacteria were Proteus vulgaris. We found that the surface charge of the silver nanoparticles was a significant factor affecting bactericidal activity on these surfaces. Although the positively charged nanoparticles showed the highest level of effectiveness against the organisms tested, the neutrally charged particles were also potent against most bacterial species.

  19. Radiographic study of bone deformans on charged condylar head position in TMJ arthrosis

    International Nuclear Information System (INIS)

    You, Dong Soo

    1983-01-01

    The author analyzed the morphologic changes of bone structure from 848 radiographics (424 joints) of 212 patients with temporomandibular joint arthrosis, which were obtained by the oblique-lateral transcranial projection and ortho pantomography. The interrelation of the bone changes and condylar head positions the results were as follows: 1. In the 212 patients with TMJ arthrosis, 210 patients (99.05%) show the condylar positional changes. Among them, 187 patients (89.05%) show the bone changes. 2. In TMJ arthrosis patients with bone changes, 108 patients (57.75%) show both the condylar positional changes and bone changes. 66 patients show the condylar positional changes bilaterally and bone changes unilaterally. On the other hand, 11 patients (5.88%) show the condylar positional changes unilaterally and bone change bilaterally. 3. The bone changes in the TMJ arthrosis patients with the condylar positional changes were as follows: There were the flattening of articular surface in 103 cases (26.55%) the erosion in 99 cases (25.52%), and the erosion in 88 cases (22.68%). There were not much differences among the three types of bone changes. And the deformity in 70 cases (18.04%), the sclerosis in 22 cases (5.67%), the marginal proliferation in 6 cases (1.55%) were seen. 4. The regions of bone changes in TMJ arthrosis patients with condylar positional changes were as follows: They occurred at the condyle head (51.04%), the articular eminence (39.20%) and the articular fossa (9.60%) in that order. The condylar positional changes and bone changes according to the regions were as follows: a) In the bone changes at the condylar head, the flattening (34.63%) was a most frequent finding and the deformity (27.63%) the erosion (34.63%) in the order. In the condylar positional changes, the downward positioning of condyle (41.44%) was a most frequent finding in the mouth closed state and the restricted movement within the articular fossa (35.46%) in the mouth open state. b) In

  20. Radiographic study of bone deformans on charged condylar head position in TMJ arthrosis

    Energy Technology Data Exchange (ETDEWEB)

    You, Dong Soo [Department of Oral Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1983-11-15

    The author analyzed the morphologic changes of bone structure from 848 radiographics (424 joints) of 212 patients with temporomandibular joint arthrosis, which were obtained by the oblique-lateral transcranial projection and ortho pantomography. The interrelation of the bone changes and condylar head positions the results were as follows: 1. In the 212 patients with TMJ arthrosis, 210 patients (99.05%) show the condylar positional changes. Among them, 187 patients (89.05%) show the bone changes. 2. In TMJ arthrosis patients with bone changes, 108 patients (57.75%) show both the condylar positional changes and bone changes. 66 patients show the condylar positional changes bilaterally and bone changes unilaterally. On the other hand, 11 patients (5.88%) show the condylar positional changes unilaterally and bone change bilaterally. 3. The bone changes in the TMJ arthrosis patients with the condylar positional changes were as follows: There were the flattening of articular surface in 103 cases (26.55%) the erosion in 99 cases (25.52%), and the erosion in 88 cases (22.68%). There were not much differences among the three types of bone changes. And the deformity in 70 cases (18.04%), the sclerosis in 22 cases (5.67%), the marginal proliferation in 6 cases (1.55%) were seen. 4. The regions of bone changes in TMJ arthrosis patients with condylar positional changes were as follows: They occurred at the condyle head (51.04%), the articular eminence (39.20%) and the articular fossa (9.60%) in that order. The condylar positional changes and bone changes according to the regions were as follows: a) In the bone changes at the condylar head, the flattening (34.63%) was a most frequent finding and the deformity (27.63%) the erosion (34.63%) in the order. In the condylar positional changes, the downward positioning of condyle (41.44%) was a most frequent finding in the mouth closed state and the restricted movement within the articular fossa (35.46%) in the mouth open state. b) In

  1. [Decontamination of organophosphorus compounds: Towards new alternatives].

    Science.gov (United States)

    Poirier, L; Jacquet, P; Elias, M; Daudé, D; Chabrière, E

    2017-05-01

    Organophosphorus coumpounds (OP) are toxic chemicals mainly used for agricultural purpose such as insecticides and were also developed and used as warfare nerve agents. OP are inhibitors of acetylcholinesterase, a key enzyme involved in the regulation of the central nervous system. Chemical, physical and biological approaches have been considered to decontaminate OP. This review summarizes the current and emerging strategies that are investigated to tackle this issue with a special emphasis on enzymatic remediation methods. During the last decade, many studies have been dedicated to the development of biocatalysts for OP removal. Among these, recent reports have pointed out the promising enzyme SsoPox isolated from the archaea Sulfolobus solfataricus. Considering both its intrinsic stability and activity, this hyperthermostable enzyme is highly appealing for the decontamination of OP. Copyright © 2017 Académie Nationale de Pharmacie. All rights reserved.

  2. Humic acid adsorption onto cationic cellulose nanofibers for bioinspired removal of copper( ii ) and a positively charged dye

    KAUST Repository

    Sehaqui, H.

    2015-01-01

    © The Royal Society of Chemistry. Waste pulp residues are herein exploited for the synthesis of a sorbent for humic acid (HA), which is a major water pollutant. Cellulose pulp was etherified with a quaternary ammonium salt in water thereby introducing positive charges onto the surface of the pulp fibers, and subsequently mechanically disintegrated into high surface area cellulose nanofibers (CNF). CNF with three different charge contents were produced and their adsorption capacity towards HA was investigated with UV-spectrophotometry, quartz crystal microbalance with dissipation, and ζ-potential measurements. Substantial coverage of the CNF surface with HA in a wide pH range led to a reversal of the positive ζ-potentials of CNF suspensions. The HA adsorption capacity and the kinetics of HA uptake were found to be promoted by both acidic pH conditions and the surface charge content of CNF. It is suggested that HA adsorption onto CNF depends on electrostatic interactions between the two components, as well as on the conformation of HA. At pH ∼ 6, up to 310 mg g-1 of HA were adsorbed by the functionalized CNF, a substantially higher capacity than that of previously reported HA sorbents in the literature. It is further shown that CNF-HA complexes could be freeze-dried into "soil-mimicking" porous foams having good capacity to capture Cu(ii) ions and positive dyes from contaminated water. Thus, the most abundant natural polymer, i.e., cellulose could effectively bind the most abundant natural organic matter for environmental remediation purpose.

  3. Memory for media: investigation of false memories for negatively and positively charged public events.

    Science.gov (United States)

    Porter, Stephen; Taylor, Kristian; Ten Brinke, Leanne

    2008-01-01

    Despite a large body of false memory research, little has addressed the potential influence of an event's emotional content on susceptibility to false recollections. The Paradoxical Negative Emotion (PNE) hypothesis predicts that negative emotion generally facilitates memory but also heightens susceptibility to false memories. Participants were asked whether they could recall 20 "widely publicised" public events (half fictitious) ranging in emotional valence, with or without visual cues. Participants recalled a greater number of true negative events (M=3.31/5) than true positive (M=2.61/5) events. Nearly everyone (95%) came to recall at least one false event (M=2.15 false events recalled). Further, more than twice as many participants recalled any false negative (90%) compared to false positive (41.7%) events. Negative events, in general, were associated with more detailed memories and false negative event memories were more detailed than false positive event memories. Higher dissociation scores were associated with false recollections of negative events, specifically.

  4. Charge Inversion of Phospholipids by Dimetal Complexes for Positive Ion-Mode Electrospray Ionization Mass Spectrometry Analysis

    DEFF Research Database (Denmark)

    Svane, Simon; Gorshkov, Vladimir; Kjeldsen, Frank

    2015-01-01

    charges per phosphate group. Three different phosphoinositide phosphates (mono-, di-, and triphosphorylated inositides), a phosphatidic acid, a phosphatidylcholine, a phosphatidylethanolamine, and a phosphatidylglycerol were investigated. The intensities obtained in positive ion-mode of phosphoinositide...... phosphates and phosphatidic acid bound to {LGa2}(5+) were between 2.5- and 116-fold higher than that of the unmodified lipids in the negative ion-mode. Native phosphoinositide ions yielded upon CID in the negative ion-mode predominantly product ions due to losses of H3PO4, PO3(-) and H2O. In comparison, CID...

  5. Role of uniform pore structure and high positive charges in the arsenate adsorption performance of Al13-modified montmorillonite

    International Nuclear Information System (INIS)

    Zhao, Shou; Feng, Chenghong; Huang, Xiangning; Li, Baohua; Niu, Junfeng; Shen, Zhenyao

    2012-01-01

    Highlights: ► Al 13 modification changes As(V) sorption mechanism of montmorillonites. ► Intercalated ion charges mainly affects As(V) adsorption kinetics. ► Uniform pore structure exhibit more excellent As(V) adsorption performance. - Abstract: Four modified montmorillonite adsorbents with varied Al 13 contents (i.e., Na-Mont, AC-Mont, PAC 20 -Mont, and Al 13 -Mont) were synthesized and characterized by N 2 adsorption/desorption, X-ray diffraction, and Fourier-transform infrared analyses. The arsenate adsorption performance of the four adsorbents were also investigated to determine the role of intercalated Al 13 , especially its high purity, high positive charge (+7), and special Keggin structure. With increased Al 13 content, the physicochemical properties (e.g., surface area, structural uniformity, basal spacing, and pore volume) and adsorption performance of the modified montmorillonites were significantly but disproportionately improved. The adsorption data well fitted the Freundlich and Redlich–Peterson isotherm model, whereas the kinetic data better correlated with the pseudo-second-order kinetic model. The arsenate sorption mechanism of the montmorillonites changed from physical to chemisorption after intercalation with Al 13 . Increasing charges of the intercalated ions enhanced the arsenate adsorption kinetics, but had minimal effect on the structural changes of the montmorillonites. The uniform pore structure formed by intercalation with high-purity Al 13 greatly enhanced the pore diffusion and adsorption rate of arsenate, resulting in the high adsorption performance of Al 13 -Mont.

  6. Effect of nuclear shielding in collision of positive charged helium ions with helium atoms

    Science.gov (United States)

    Ghavaminia, Hoda; Ghavaminia, Shirin

    2018-03-01

    Differential in angle and absolute cross sections in energy of the scattered particles are obtained for single charge exchange in ^3He^+-^4He collisions by means of the four body boundary-corrected first Born approximation (CB1-4B). The quantum-mechanical post and prior transition amplitudes are derived in terms of two-dimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. The effect of the dynamic electron correlation through the complete perturbation potential and the nuclear-screening influence of the passive electrons on the electron capture process is investigated. The results obtained in the CB1-4B method are compared with the available experimental data. For differential cross sections, the present results are in better agreement with experimental data than other theoretical data at extreme forward scattering angles. The integral cross sections are in excellent agreement with the experiment. Also, total cross sections for single electron capture, has been investigated using the classical trajectory Monte Carlo method. The present calculated results are found to be in an excellent agreement with the experimental data.

  7. High Efficiency, Low EMI and Positioning Tolerant Wireless Charging of EVs

    Energy Technology Data Exchange (ETDEWEB)

    Chabaan, Rakan [Hyundai American Technical Center Inc. (HATCI), Superior Twp, MI (United States)

    2017-12-01

    The objective of this project is to develop, implement, and demonstrate a wireless power transfer (WPT) system that is capable of the following metrics: Total system efficiencies of more than 85 percent with minimum 20 cm coil-to-coil gap; System output power at least 6.6 kW; but design system up to 19.2 kW for future higher power study; Maximum lateral positioning tolerance achievable while meeting regulatory emission guidelines.

  8. Investigation of the electrochemical and electrocatalytic behavior of positively charged gold nanoparticle and L-cysteine film on an Au electrode

    International Nuclear Information System (INIS)

    Zhang Lingyan; Yuan Ruo; Chai Yaqing; Li Xuelian

    2007-01-01

    Positively charged gold nanoparticle (positively charged nano-Au), which was prepared, characterized by ξ-potential and transmission electron microscopy (TEM) was used in combination with L-cysteine to fabricate a modified electrode for electrocatalytic reaction of biomolecules. Compared with electrodes modified by negatively charged gold nanoparticle/L-cysteine, or L-cysteine alone, the electrode modified by the positively charged gold nanoparticle/L-cysteine exhibited excellent electrochemical behavior toward the oxidation of biomolecules such as ascorbic acid, dopamine and hydrogen peroxide. Moreover, the proposed mechanism for electrocatalytic response of positively charged gold nanoparticle was discussed. The immunosensor showed a specific to ascorbic acid in the range 5.1 x 10 -7 -6.7 x 10 -4 M and a low detection limit of 1.5 x 10 -7 M. The experimental results demonstrate that positively charged gold nanoparticle have more efficient electrocatalytic reaction than negatively charged gold nanoparticle, which opens up new approach for fabricating sensor

  9. The Positively Charged Hyperbranched Polymers with Tunable Fluorescence and the Cell Imaging Application.

    Science.gov (United States)

    Ma, Hengchang; Qin, Yanfang; Yang, Zenming; Yang, Manyi; Ma, Yucheng; Yin, Pei; Yang, Yuan; Wang, Tao; Lei, Ziqiang; Yao, Xiaoqiang

    2018-04-25

    Fluorescence-tunable materials are becoming increasingly attractive for their potential application in optics, electronics, and biomedical technology. Herein, a multi-color molecular pixel system is realized using simple copolymerization method. Bleeding both of complementary colors from blue and yellow fluorescence segments, reproduced a serious multicolor fluorescence materials. Interestingly, the emission colors of the polymers can be fine-tuned in solid state, solution phase, and in hydrogel state. More importantly, the positive fluorescent polymers exhibited cell-membrane permeable ability, and were found to accumulate on the cell nucleus, exhibiting remarkable selectivity to give bright fluorescence. The DNA/RNA selectivity experiments in vitro and in vivo verified that [tris(4-(pyridin-4-yl)phenyl)amine]-[1,8-dibromooctane] (TPPA-DBO) has prominent selectivity to DNA over RNA inside cells.

  10. Supplementary Material for: Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad B. S.

    2017-01-01

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  11. Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad

    2016-08-22

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  12. Influence of joint direction and position of explosive charge on fragmentation

    International Nuclear Information System (INIS)

    Hafsaoui, Abdellah; Talhi, Korichi

    2009-01-01

    Although researchers have realized varying degrees of success in small-scale physical in situ testing, most will agree that the greatest uncertainty stems from the uncontrollable field variables. Given the diverse nature of field conditions encountered, there exists no reliable and proven method of predicting fragmentation. Due to the lack of adequate field controls, it is unlikely that a universal physical model will ever be developed for all blasting. This paper presents the results of a test conducted at the Hadjar Essoud quarry to investigate the problems associated with the discontinuities in the rock, which are among the factors causing the reduction of the resistance of the rocks to the explosive. Nevertheless, the distance between the joints, their dip and strike, and the position of the detonator play a significant role in the final fragmentation of the rock. In this work, we studied the role of the abovementioned factors on models of limestone rock of 150 X 375 X 450 mm. Accurate measurement of blast, fragmentation is important in mining and quarrying operations, in monitoring blasts, and optimizing their design. We shall use the Kuznetsov-Rammler method to measure fragmentation. It shows great potential as a practical aid to predict and control the quality of the fragmented material in the Hadjar Essoud quarry. (author)

  13. Measurement of Production Properties of Positively Charged Kaons in Proton-Carbon Interactions at 31 GeV/c

    CERN Document Server

    Abgrall, N.; Anticic, T.; Antoniou, N.; Argyriades, J.; Baatar, B.; Blondel, A.; Blumer, J.; Bogusz, M.; Boldizsar, L.; Bravar, A.; Brooks, W.; Brzychczyk, J.; Bubak, A.; Bunyatov, S.A.; Busygina, O.; Cetner, T.; Choi, K.U.; Christakoglou, P.; Czopowicz, T.; Davis, N.; Diakonos, F.; Di Luise, S.; Dominik, W.; Dumarchez, J.; Engel, R.; Ereditato, A.; Esposito, L.S.; Feofilov, G.A.; Fodor, Z.; Ferrero, A.; Fulop, A.; Garrido, X.; Gazdzicki, M.; Golubeva, M.; Grebieszkow, K.; Grzeszczuk, A.; Guber, F.; Haesler, A.; Hakobyan, H.; Hasegawa, T.; Idczak, R.; Ivanov, Y.; Ivashkin, A.; Kadija, K.; Kapoyannis, A.; Katrynska, N.; Kielczewska, D.; Kikola, D.; Kim, J.H.; Kirejczyk, M.; Kisiel, J.; Kobayashi, T.; Kochebina, O.; Kolesnikov, V.I.; Kolev, D.; Kondratiev, V.P.; Korzenev, A.; Kowalski, S.; Krasnoperov, A.; Kuleshov, S.; Kurepin, A.; Lacey, R.; Lagoda, J.; Laszlo, A.; Lyubushkin, V.V.; Mackowiak-Pawlowska, M.; Majka, Z.; Malakhov, A.I.; Marchionni, A.; Marcinek, A.; Maris, I.; Marin, V.; Matulewicz, T.; Matveev, V.; Melkumov, G.L.; Meregaglia, A.; Messina, M.; Mrowczynski, St.; Murphy, S.; Nakadaira, T.; Nishikawa, K.; Palczewski, T.; Palla, G.; Panagiotou, A.D.; Paul, T.; Peryt, W.; Petukhov, O.; Planeta, R.; Pluta, J.; Popov, B.A.; Posiadala, M.; Pulawski, S.; Rauch, W.; Ravonel, M.; Renfordt, R.; Robert, A.; Rohrich, D.; Rondio, E.; Rossi, B.; Roth, M.; Rubbia, A.; Rybczynski, M.; Sadovsky, A.; Sakashita, K.; Sekiguchi, T.; Seyboth, P.; Shibata, M.; Skrzypczak, E.; Slodkowski, M.; Staszel, P.; Stefanek, G.; Stepaniak, J.; Strabel, C.; Strobele, H.; Susa, T.; Szaflik, P.; Szuba, M.; Tada, M.; Taranenko, A.; Tereshchenko, V.; Tsenov, R.; Turko, L.; Ulrich, R.; Unger, M.; Vassiliou, M.; Veberic, D.; Vechernin, V.V.; Vesztergombi, G.; Wilczek, A.; Wlodarczyk, Z.; Wojtaszek-Szwarc, A.; Yi, J.G.; Yoo, I.K.; Zambelli, L.; Zipper, W.

    2012-01-01

    Spectra of positively charged kaons in p+C interactions at 31 GeV/c were measured with the NA61/SHINE spectrometer at the CERN SPS. The analysis is based on the full set of data collected in 2007 with a graphite target with a thickness of 4% of a nuclear interaction length. Interaction cross sections and charged pion spectra were already measured using the same set of data. These new measurements in combination with the published ones are required to improve predictions of the neutrino flux for the T2K long baseline neutrino oscillation experiment in Japan. In particular, the knowledge of kaon production is crucial for precisely predicting the intrinsic electron neutrino component and the high energy tail of the T2K beam. The results are presented as a function of laboratory momentum in 2 intervals of the laboratory polar angle covering the range from 20 up to 240 mrad. The kaon spectra are compared with predictions of several hadron production models. Using the published...

  14. Approximate energies and thermal properties of a position-dependent mass charged particle under external magnetic fields

    Institute of Scientific and Technical Information of China (English)

    M Eshghi; H Mehraban; S M Ikhdair

    2017-01-01

    We solve the Schr(o)dinger equation with a position-dependent mass (PDM) charged particle interacted via the superposition of the Morse-plus-Coulomb potentials and is under the influence of external magnetic and Aharonov-Bohm (AB) flux fields.The nonrelativistic bound state energies together with their wave functions are calculated for two spatially-dependent mass distribution functions.We also study the thermal quantifies of such a system.Further,the canonical formalism is used to compute various thermodynamic variables for second choosing mass by using the Gibbs formalism.We give plots for energy states as a function of various physical parameters.The behavior of the internal energy,specific heat,and entropy as functions of temperature and mass density parameter in the inverse-square mass case for different values of magnetic field are shown.

  15. Approximate energies and thermal properties of a position-dependent mass charged particle under external magnetic fields

    International Nuclear Information System (INIS)

    Eshghi, M; Mehraban, H; Ikhdair, S M

    2017-01-01

    We solve the Schrödinger equation with a position-dependent mass (PDM) charged particle interacted via the superposition of the Morse-plus-Coulomb potentials and is under the influence of external magnetic and Aharonov–Bohm (AB) flux fields. The nonrelativistic bound state energies together with their wave functions are calculated for two spatially-dependent mass distribution functions. We also study the thermal quantities of such a system. Further, the canonical formalism is used to compute various thermodynamic variables for second choosing mass by using the Gibbs formalism. We give plots for energy states as a function of various physical parameters. The behavior of the internal energy, specific heat, and entropy as functions of temperature and mass density parameter in the inverse-square mass case for different values of magnetic field are shown. (paper)

  16. Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

    Science.gov (United States)

    Muranaka, T.; Debu, P.; Dupré, P.; Liszkay, L.; Mansoulie, B.; Pérez, P.; Rey, J. M.; Ruiz, N.; Sacquin, Y.; Crivelli, P.; Gendotti, U.; Rubbia, A.

    2010-04-01

    We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5·1011 per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

  17. Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

    International Nuclear Information System (INIS)

    Muranaka, T; Debu, P; Dupre, P; Liszkay, L; Mansoulie, B; Perez, P; Rey, J M; Ruiz, N; Sacquin, Y; Crivelli, P; Gendotti, U; Rubbia, A

    2010-01-01

    We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5·10 11 per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

  18. Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Muranaka, T; Debu, P; Dupre, P; Liszkay, L; Mansoulie, B; Perez, P; Rey, J M; Ruiz, N; Sacquin, Y [Irfu, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Crivelli, P; Gendotti, U; Rubbia, A, E-mail: tomoko.muranaka@cea.f [Institut fuer TelichenPhysik, ETHZ, CH-8093 Zuerich (Switzerland)

    2010-04-01

    We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5{center_dot}10{sup 11} per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

  19. Long-Term Charge/Discharge Cycling Stability of MnO2 Aqueous Supercapacitor under Positive Polarization

    KAUST Repository

    Ataherian, Fatemeh

    2011-01-01

    The long-term charge/discharge cycling stability of MnO 2 electrode under positive polarization in aqueous KCl electrolyte has been studied over different potential windows spanning from the open circuit potential to varied higher-end potential limited by O 2 evolution. Cycling up to 1.2 V (vs Ag/AgCl (aq)) causes partial (35) capacitance fading to a plateau value within the initial cycles, accompanied by morphological reconstruction, reduction of surface Mn ions and oxygen evolution. The surface Mn-ion reduction has been attributed to a two-step oxidation-reduction mechanism involving OH oxidation in electrolyte, based on electrochemical analysis. When cycling potential extends to 1.4 V, extensive oxygen evolution takes place. The combination of surface passivation of current collector and extensive gas bubbling, which deteriorates electrical contact among the constituent particles within the electrode, results in further monotonic capacitance reduction. © 2011 The Electrochemical Society.

  20. Effect of positively charged short peptides on stability of cubic phases of monoolein/dioleoylphosphatidic acid mixtures.

    Science.gov (United States)

    Masum, Shah Md; Li, Shu Jie; Awad, Tarek S; Yamazaki, Masahito

    2005-06-07

    To elucidate the stability and phase transition of cubic phases of biomembranes with infinite periodic minimal surface is indispensable from biological and physicochemical aspects. In this report, we investigated the effect of positively charged peptide-3K (LLKKK) and poly(L-lysine) on the phase stability of monoolein (MO) membranes containing negatively charged dioleoylphosphatidic acid (DOPA) (i.e., DOPA/MO membranes) using small-angle X-ray scattering. At first, the effect of peptide-3K on 10% DOPA/90% MO membrane in excess water, which is in the Q229 phase, was investigated. At 3.4 mM peptide-3K, a Q229 to Q230 phase transition occurred, and at >3.4 mM peptide-3K, the membrane was in the Q230 phase. Poly(L-lysine) (M(w) 1K-4K) also induced the Q230 phase, but peptide-2K (LLKK) could not induce it in the same membrane. We also investigated the effect of peptide-3K on the multilamellar vesicle (MLV) of 25% DOPA/75% MO membrane, which is in L(alpha) phase. In the absence of peptide, the spacing of MLV was very large (11.3 nm), but at > or = 8 mM peptide-3K, it greatly decreased to a constant value (5.2 nm), irrespective of the peptide concentration, indicating that peptide-3K and the membranes form an electrostatically stabilized aggregation with low water content. Poly(L-lysine) also decreased greatly the spacing of the 25% DOPA/75% MO MLV, indicating the formation of a similar aggregation. To compare the effects of peptide-3K and poly(L-lysine) with that of osmotic stress on stability of the cubic phase, we investigated the effect of poly(ethylene glycol) with molecular weight 7500 (PEG-6K) on the phase stability of 10% DOPA/90% MO membrane. With an increase in PEG-6K concentration, i.e., with an increase in osmotic stress, the most stable phase changed as follows; Q229 (Schwartz's P surface) --> Q224 (D) --> Q230 (G). On the basis of these results, we discuss the mechanism of the effects of the positively charged short peptides (peptide-3K) and poly

  1. Levels and distribution of organophosphorus flame retardants and plasticizers in fishes from Manila Bay, the Philippines

    International Nuclear Information System (INIS)

    Kim, Joon-Woo; Isobe, Tomohiko; Chang, Kwang-Hyeon; Amano, Atsuko; Maneja, Rommel H.; Zamora, Peter B.; Siringan, Fernando P.; Tanabe, Shinsuke

    2011-01-01

    Organophosphorus compounds (OPCs) and stable isotope ratios (δ 13 C and δ 15 N) were determined in 58 fishes belonging to 20 species collected from Manila Bay, the Philippines. OPCs were detected in most of the samples and found up to μg/g lw (lipid weight) level, suggesting their ubiquitous presence in the coastal marine environment of the Philippines. Higher levels (>1000 ng/g lw) of total OPCs were determined in yellowstriped goatfish, silver sillago, tripletail wrasse and bumpnose trevally indicates either their active uptake from ambient water or lower metabolic capacity of these species. Levels of triphenyl phosphate (TPhP) in demersal species showed a positive correlation with δ 15 N, indicating that TPhP was adsorbed onto the particle, settled down to the bottom sediment and accumulated through the benthic food web rather than the pelagic. Estimated dietary intake of OPCs in Manila Bay fishes were four to five orders of magnitude lower than the proposed reference dose (RfD). - Highlights: → Organophosphorus compounds (OPCs) were determined in fish from Manila Bay. → OPCs were detected up to μg/g lw, suggesting ubiquitous environmental contamination. → Among the 9 targeted OPCs, TEHP and TEP were found as the predominant compounds. → Estimated dietary intake through fish consumption was 4-5 orders of magnitude lower than RfD. → This is the first report on OPCs pollution in marine environment of Southeast Asia. - Occurrence and bioaccumulation of organophosphorus compounds (OPCs) were determined in fishes from Manila Bay.

  2. Simulation study on discrete charge effects of SiNW biosensors according to bound target position using a 3D TCAD simulator.

    Science.gov (United States)

    Chung, In-Young; Jang, Hyeri; Lee, Jieun; Moon, Hyunggeun; Seo, Sung Min; Kim, Dae Hwan

    2012-02-17

    We introduce a simulation method for the biosensor environment which treats the semiconductor and the electrolyte region together, using the well-established semiconductor 3D TCAD simulator tool. Using this simulation method, we conduct electrostatic simulations of SiNW biosensors with a more realistic target charge model where the target is described as a charged cube, randomly located across the nanowire surface, and analyze the Coulomb effect on the SiNW FET according to the position and distribution of the target charges. The simulation results show the considerable variation in the SiNW current according to the bound target positions, and also the dependence of conductance modulation on the polarity of target charges. This simulation method and the results can be utilized for analysis of the properties and behavior of the biosensor device, such as the sensing limit or the sensing resolution.

  3. Simulation study on discrete charge effects of SiNW biosensors according to bound target position using a 3D TCAD simulator

    International Nuclear Information System (INIS)

    Chung, In-Young; Moon, Hyunggeun; Jang, Hyeri; Lee, Jieun; Kim, Dae Hwan; Seo, Sung Min

    2012-01-01

    We introduce a simulation method for the biosensor environment which treats the semiconductor and the electrolyte region together, using the well-established semiconductor 3D TCAD simulator tool. Using this simulation method, we conduct electrostatic simulations of SiNW biosensors with a more realistic target charge model where the target is described as a charged cube, randomly located across the nanowire surface, and analyze the Coulomb effect on the SiNW FET according to the position and distribution of the target charges. The simulation results show the considerable variation in the SiNW current according to the bound target positions, and also the dependence of conductance modulation on the polarity of target charges. This simulation method and the results can be utilized for analysis of the properties and behavior of the biosensor device, such as the sensing limit or the sensing resolution. (paper)

  4. Biodegradation of organophosphorus pesticides by soil bacteria

    Science.gov (United States)

    de Pasquale, C.; Fodale, R.; Lo Piccolo, L.; Palazzolo, E.; Alonzo, G.; Quatrini, P.

    2009-04-01

    A number of studies in the 1980s and 1990s showed that crop-protection products, applied to drained fields, could move downwards through the soil profile and to the groundwater. Organophosphorus insecticides (OPs) are used all over the world for crop protection, for other agricultural practices such as sheep dipping and, in aquaculture, for the control of sea lice. Ops besides showing a specific neurotoxicity and have also been related to various modern diseases, including Creutzfeldt-Jakob (CJD) and the Gulf War syndrome. Although OPs are less persistent than Organoclorine pesticides (OCs), they still constitute an environmental risks thus increasing the social concern about their levels in soils, surface waters, and ground waters. Degradation of OPs by microorganisms has been assessed for a few bacterial strains. In the present study the OPs degrading potential of indigenous soil microorganisms was investigated. Using enrichment cultures in which parathion was the only C and energy sources many bacterial strains were isolated from OPs contaminated and pristine agricultural soils characterized by different physico-chemical properties. More than 40 potential OPs degraders were isolated and grouped in operational taxonomic units (OTU) using analysis of polymorphism showed by the ribosomal internal transcribed spacer (ITS). Partial sequencing of 16S rRNA gene of representative isolates of each OTU revealed that most of them belong to Proteobacteria and Actinobacteria. All the analyzed soils showed the presence of putative OPs degraders: the highest diversity was found in organic cultivated soils, the lowest in chemically cultivated soils. Degradation of different OPs, characterized by different physical and chemical properties, was obtained by different selected representative strains using SPME GC-MS analysis on water and soil microcosms. The results showed that, after the incubation period, the amount of pesticide residues were in the range 20-80%. Some of the

  5. Study of Serum Amylase and Serum Cholinesterase in Organophosphorus Poisoning

    Directory of Open Access Journals (Sweden)

    Sharan Badiger

    2016-04-01

    Full Text Available Background: Poisoning due to organophosphorus compounds is most commonly seen. Earlier plasma cholinesterase level was used to assess the severity of poisoning. Presently serum amylase is being recommended as a better indicator of severity. Aims and Objectives: To study plasma cholinesterase and serum amylase levels in acute organophosphorus and to correlate serum amylase levels with clinical severity and outcome. Material and Methods: A total of 80 patients in the study admitted to a tertiary care centre within 24 hours with a history of organophosphorus poisoning were included in study. Estimation of plasma cholinesterase and serum rd amylase was done at the time of admission, and on 3 th day and on 5 day. Results: Occurrence of organophosphorus poisoning was more common among age group 21-30 years and among males (57.5%. They were 25 (31.2% farmers, 23 (28.8% st u d e n ts, a n d 2 2 ( 2 7 . 5% h o u s ewi v e s. Monocrotophos (45.0% was commonly used compound. Mean value of plasma cholinesterase and serum amylase at admission are 3693 U/L, and 185.4 U/L. There was significant inhibition of plasma cholinesterase and elevation of serum amylase at th admission with return to normal values on 5 day. Conclusion: Plasma cholinesterase inhibition 200 U/L has been associated with poor prognosis and proneness to respiratory failure.

  6. Acute organophosphorus compound poisoning in cattle: A case report

    African Journals Online (AJOL)

    A case of an acute organophosphorus compound, GOLDFLEECE poisoning involving 39 cattle at Abubakar Tafawa Balewa University, Bauchi is reported. The animals were overexposed to the compound following routine tick spray. Within 15 minutes after the spray of the compound, 26 animals were recumbent showing ...

  7. Acute organo-phosphorus pesticide poisoning in North Karnataka ...

    African Journals Online (AJOL)

    Background: Pesticide poisoning is an important cause of morbidity and mortality in India. Objectives: To assess the oxidative damage, hemoglobin level and leukocyte count in acute organophosphorus pesticide poisoning. Methods: Plasma cholinesterase was assessed as a toxicity marker. Oxidative damage was ...

  8. Positive Charges on the Surface of Thaumatin Are Crucial for the Multi-Point Interaction with the Sweet Receptor.

    Science.gov (United States)

    Masuda, Tetsuya; Kigo, Satomi; Mitsumoto, Mayuko; Ohta, Keisuke; Suzuki, Mamoru; Mikami, Bunzo; Kitabatake, Naofumi; Tani, Fumito

    2018-01-01

    Thaumatin, an intensely sweet-tasting protein, elicits sweet taste with a threshold of only 50 nM. Previous studies from our laboratory suggested that the complex model between the T1R2-T1R3 sweet receptor and thaumatin depends critically on the complementarity of electrostatic potentials. In order to further validate this model, we focused on three lysine residues (Lys78, Lys106, and Lys137), which were expected to be part of the interaction sites. Three thaumatin mutants (K78A, K106A, and K137A) were prepared and their threshold values of sweetness were examined. The results showed that the sweetness of K106A was reduced by about three times and those of K78A and K137A were reduced by about five times when compared to wild-type thaumatin. The three-dimensional structures of these mutants were also determined by X-ray crystallographic analyses at atomic resolutions. The overall structures of mutant proteins were similar to that of wild-type but the electrostatic potentials around the mutated sites became more negative. Since the three lysine residues are located in 20-40 Å apart each other on the surface of thaumatin molecule, these results suggest the positive charges on the surface of thaumatin play a crucial role in the interaction with the sweet receptor, and are consistent with a large surface is required for interaction with the sweet receptor, as proposed by the multipoint interaction model named wedge model.

  9. Bose-Einstein study of position-momentum correlations of charged pions in hadronic $Z^{0}$ decays

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A., Jr.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2007-01-01

    A study of Bose-Einstein correlations in pairs of identically charged pions produced in e+e- annihilations at the Z0 peak has been performed for the first time assuming a non-static emitting source. The results are based on the high statistics data obtained with the OPAL detector at LEP. The correlation functions have been analyzed in intervals of the average pair transverse momentum and of the pair rapidity, in order to study possible correlations between the pion production points and their momenta (position-momentum correlations). The Yano-Koonin and the Bertsch-Pratt parameterizations have been fitted to the measured correlation functions to estimate the geometrical parameters of the source as well as the velocity of the source elements with respect to the overall centre-of-mass frame. The source rapidity is found to scale approximately with the pair rapidity, and both the longitudinal and transverse source dimensions are found to decrease for increasing average pair transverse momenta.

  10. The role of space charge in the performance of the bunching system for the ATLAS Positive Ion Injector

    International Nuclear Information System (INIS)

    Pardo, R.C.; Smith, R.

    1995-01-01

    The bunching system of the ATLAS Positive Ion Injector consists of a four-frequency harmonic buncher, a beam-tail removing chopper, and a 24.25 MHz spiral resonator sine-wave rebuncher. The system is designed to efficiently create beam pulses of approximately 0.25 nsec FWHM for injection into mid acceleration by the ATLAS superconducting linac. Studies of the effect of space charge on the performance of the system have been undertaken and compared to simulations as part of the design process for a new bunching system to be developed for a second ion source. Results of measurements and modeling studies indicate that the present system suffers significant bunching performance deterioration at beam currents as low as 5 eμA for 238 U 26+ at a velocity of β=0.0085. The low beam current tolerance of the present system is in reasonable agreement with computer simulation. Studies of two alternatives to the present bunching system are discussed and their limitations are explored

  11. Confirmed organophosphorus and carbamate pesticide poisonings in South African wildlife (2009–2014

    Directory of Open Access Journals (Sweden)

    Christo J. Botha

    2015-12-01

    Full Text Available During a six-year period (from January 2009 to December 2014, specimens collected from 344 cases of suspected organophosphorus and carbamate pesticide poisonings in wildlife, including birds, were submitted to the Toxicology Laboratory (ARC-OVI for analysis. A positive diagnosis was made in 135 (39% of these cases. The majority of cases were from birds, which included Cape vultures (Gyps coprotheres and African white-backed vultures (Gyps africanus and bateleur eagles (Terathopius ecaudatus. In one incident 49 vultures were killed when a farmer intentionally laced carcasses with carbofuran in an attempt to control jackal predation. There were 22 incidents of poisoning in helmeted guineafowl (Numida meleagris. On nine different occasions blue cranes (Anthropoides paradiseus were poisoned, in one incident 14 birds were reported to have been killed. Over the period of investigation, there were 20 cases of poisoning involving mammalian species, the majority being vervet monkeys (Chlorocebus pygerythrus. The carbamate pesticides were responsible for 57 incidents of poisoning. Aldicarb, carbofuran and methomyl were detected in 26, 18 and 12 cases respectively. The majority of organophosphorus pesticide poisonings were caused by diazinon (n = 19, monocrotophos (n = 13 and methamidophos (n = 10.

  12. Osmoregulatory function in ducks following ingestion of the organophosphorus insecticide fenthion

    Science.gov (United States)

    Rattner, B.A.; Fleming, W.J.; Murray, H.C.

    1983-01-01

    Salt gland function and osmoregulation in aquatic birds drinking hyperosmotic water has been suggested to be impaired by organophosphorus insecticides. To test this hypothesis, adult black ducks (Anas rubripes) were provided various regimens of fresh or salt (1.5% NaCl) water before, during, and after ingestion of mash containing 21 ppm fenthion. Ducks were bled by jugular venipuncture after I, 7. and 12 days of treatment, and were then killed. Brain and salt gland acetylcholinesterase activities were substantially inhibited (44-61% and 14-36%) by fenthion. However, salt gland weight and Na + -K + -ATPase activity, and plasma Na + , CI- , and osmolality, were uniformly elevated in all groups receiving salt water including those ingesting fenthion. In a second study, salt gland Na + -K + -ATPase activity in mallards (A. platyrhynchos) was not affected after in vitro incubation with either fenthion or fenthion oxon at concentrations ranging from 0.04 to 400 ?M, but was reduced in the presence of 40 and 400 ?M DDE (positive control). These findings suggest that environmentally realistic concentrations of organophosphorus insecticides do not markedly affect osmoregulatory function in adult black ducks.

  13. The noise analysis and optimum filtering techniques for a two-dimensional position sensitive orthogonal strip gamma ray detector employing resistive charge division

    International Nuclear Information System (INIS)

    Gerber, M.S.; Muller, D.W.

    1976-01-01

    The analysis of an orthogonal strip, two-dimensional position sensitive high purity germanium gamma ray detector is discussed. Position sensitivity is obtained by connecting each electrode strip on the detector to a resistor network. Charge, entering the network, divides in relation to the resistance between its entry point and the virtual earth points of the charge sensitive preamplifiers located at the end of each resistor network. The difference of the voltage pulses at the output of each preamplifier is proportional to the position at which the charge entered the resistor network and the sum of the pulse is proportional to the energy of the detected gamma ray. The analysis and spatial noise resolution is presented for this type of position sensitive detector. The results of the analysis show that the position resolution is proportional to the square root of the filter amplifier's output pulse time constant and that for energy measurement the resolution is maximized at the filter amplifier's noise corner time constant. The design of the electronic noise filtering system for the prototype gamma ray camera was based on the mathematical energy and spatial resolution equations. For the spatial channel a Gaussian trapezoidal filtering system was developed. Gaussian filtering was used for the energy channel. The detector noise model was verified by taking rms noise measurements of the filtered energy and spatial pulses from resistive readout charge dividing detectors. These measurements were within 10% of theory. (Auth.)

  14. Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

    Science.gov (United States)

    2011-01-01

    One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm−2 at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

  15. Positive Charges on the Surface of Thaumatin Are Crucial for the Multi-Point Interaction with the Sweet Receptor

    Directory of Open Access Journals (Sweden)

    Tetsuya Masuda

    2018-02-01

    Full Text Available Thaumatin, an intensely sweet-tasting protein, elicits sweet taste with a threshold of only 50 nM. Previous studies from our laboratory suggested that the complex model between the T1R2-T1R3 sweet receptor and thaumatin depends critically on the complementarity of electrostatic potentials. In order to further validate this model, we focused on three lysine residues (Lys78, Lys106, and Lys137, which were expected to be part of the interaction sites. Three thaumatin mutants (K78A, K106A, and K137A were prepared and their threshold values of sweetness were examined. The results showed that the sweetness of K106A was reduced by about three times and those of K78A and K137A were reduced by about five times when compared to wild-type thaumatin. The three-dimensional structures of these mutants were also determined by X-ray crystallographic analyses at atomic resolutions. The overall structures of mutant proteins were similar to that of wild-type but the electrostatic potentials around the mutated sites became more negative. Since the three lysine residues are located in 20–40 Å apart each other on the surface of thaumatin molecule, these results suggest the positive charges on the surface of thaumatin play a crucial role in the interaction with the sweet receptor, and are consistent with a large surface is required for interaction with the sweet receptor, as proposed by the multipoint interaction model named wedge model.

  16. Performance of a position sensitive Si(Li) x-ray detector dedicated to Compton polarimetry of stored and trapped highly-charged ions

    International Nuclear Information System (INIS)

    Weber, G; Braeuning, H; Hess, S; Maertin, R; Spillmann, U; Stoehlker, Th

    2010-01-01

    We report on a novel two-dimensional position sensitive Si(Li) detector dedicated to Compton polarimetry of x-ray radiation arising from highly-charged ions. The performance of the detector system was evaluated in ion-atom collision experiments at the ESR storage ringe at GSI, Darmstadt. Based on the data obtained, the polarimeter efficiency is estimated in this work.

  17. Alpha-conotoxin analogs with additional positive charge show increased selectivity towards Torpedo californica and some neuronal subtypes of nicotinic acetylcholine receptors

    NARCIS (Netherlands)

    Kasheverov, I.E.; Zhmak, M.N.; Vulfius, C.A.; Corbacheva, E.V.; Mordvintsev, D.Y.; Utkin, Y.N.; van Elk, R.; Smit, A.B.; Tsetlin, V.I.

    2006-01-01

    α-Conotoxins from Conus snails are indispensable tools for distinguishing various subtypes of nicotinic acetylcholine receptors (nAChRs), and synthesis of α-conotoxin analogs may yield novel antagonists of higher potency and selectivity. We incorporated additional positive charges into α-conotoxins

  18. Denaturation/Renaturation of Organophosphorus Acid Anhydrolase (OPAA) Using Guanidinium Hydrochloride and Urea

    National Research Council Canada - National Science Library

    Ong, K. K; Sun, Z; Cheng, T. C; Wei, Y; Yuan, J. M; Yin, R

    2004-01-01

    .... Using organophosphorus acid anhydrolase (OPAA) as the model protein, a guanidinium hydrochloride and urea denaturation/renaturation study was conducted and measured both optically and enzymatically...

  19. Organophosphorus pentavalent compounds: history, synthetic methods of preparation and application as insecticides and antitumor agents

    International Nuclear Information System (INIS)

    Santos, Viviane Martins Rebello dos; Donnici, Claudio Luis; DaCosta, Joao Batista Neves; Caixeiro, Janaina Marques Rodrigues

    2007-01-01

    This paper is a review of the history, synthesis and application of organophosphorus compounds, especially of those of pentavalent phosphorus, such as phosphoramidates, phosphorothioates, phosphonates and phosphonic acids with insecticide and anticancer activities. The organophosphorus compounds with agrochemical applications show great structural variety, They include not only insecticides, but also fungicides, herbicides, and others. The large variety of commercially available organophosphorus pesticides is remarkable. Even more interesting is the high efficiency of some organophosphorus compounds as anticancer agents such as cyclophosphamide and its derivatives. (author)

  20. Environmental charging of spacecraft-tests of thermal control materials for use on the global positioning system flight space vehicle. Part 2: Specimen 6 to 9

    Science.gov (United States)

    Stevens, N. J.; Berkopec, F. D.; Blech, R. A.

    1976-01-01

    The NASA/USAF program on the Environmental Charging of Spacecraft Surfaces consists, in part, of experimental efforts directed toward evaluating the response of materials to the environmental charged particle flux. Samples of thermal blankets of the type to be used on the Global Positioning System Flight Space Vehicles were tested to determine their response to electron flux. The primary result observed was that no discharges were obtained with the quartz-fiber-fabric-covered multilayer insulation specimen. The taped aluminized polyester grounding system used on all specimens did not appear to grossly deteriorate with time; however, the specimens require specific external pressure to maintain constant grounding system resistance.

  1. Biodegradation and Utilization of Organophosphorus Pesticide Malathion by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Wael M. Ibrahim

    2014-01-01

    Full Text Available Three strains of filamentous Cyanobacteria were used to study their growth and utilization of organophosphorus pesticide malathion. A sharp decrease in the growth of the algal strains was observed by increasing the concentration of malathion. Amongst them Nostoc muscorum tolerated different concentrations and was recorded as the highest efficient strain for biodegradation (91% of this compound. Moreover, carbohydrate and protein content of their cells overtopped the other strains especially at higher concentrations. The algal strains were further subjected to grow under P-limitation in absence and presence of malathion. Although, the algal growth under P-limitation recorded a very poor level, a massive enhanced growth and phosphorous content of cells were obtained when the P-limited medium was amended with malathion. This study clarified that N. muscorum with its capability to utilize malathion as a sole phosphorous source is considered as an inexpensive and efficient biotechnology for remediation of organophosphorus pesticide from contaminated wastewater.

  2. Acute organophosphorus poisoning complicated by acute coronary syndrome.

    Science.gov (United States)

    Pankaj, Madhu; Krishna, Kavita

    2014-07-01

    We report a case of 30 year old alcoholic male admitted with vomiting, drowsiness, limb weakness and fasciculations after alleged history of consumption of 30 ml of chlorpyriphos insecticide. He had low serum cholinesterase levels. With standard treatment for organophosphorus poisoning (OPP), he improved gradually until day 5, when he developed neck and limb weakness and respiratory distress. This intermediate syndrome was treated with oximes, atropine and artificial ventilation. During treatment, his ECG showed fresh changes of ST elevation. High CPK & CPK-MB levels, septal hypokinesia on 2D echo suggested acute coronary syndrome. Coronary angiography was postponed due to his bedridden and obtunded status. The patient finally recovered fully by day 15 and was discharged. Acute coronary syndrome is a rare occurrence in OP poisoning. The present case thus emphasises the need for careful electrocardiographic and enzymatic monitoring of all patients of organophosphorus poisoning to prevent potential cardiac complication which can prove fatal.

  3. Positively charged polymers modulate the fate of human mesenchymal stromal cells via ephrinB2/EphB4 signaling

    Directory of Open Access Journals (Sweden)

    Ilenia De Luca

    2016-09-01

    Full Text Available Understanding the mechanisms by which mesenchymal stromal cells (MSCs interact with the physical properties (e.g. topography, charge, ζ-potential, and contact angle of polymeric surfaces is essential to design new biomaterials capable of regulating stem cell behavior. The present study investigated the ability of two polymers (pHM1 and pHM3 with different positive surface charge densities to modulate the differentiation of MSCs into osteoblast-like phenotype via cell-cell ephrinB2/EphB4 signaling. Although pHM1 promoted the phosphorylation of EphB4, leading to cell differentiation, pHM3, characterized by a high positive surface charge density, had no significant effect on EphB4 activation or MSCs differentiation. When the MSCs were cultured on pHM1 in the presence of a forward signaling blocking peptide, the osteoblast differentiation was compromised. Our results demonstrated that the ephrinB2/EphB4 interaction was required for MSCs differentiation into an osteoblast-like phenotype and that the presence of a high positive surface charge density altered this interaction.

  4. The 4-pyridylmethyl ester as a protecting group for glutamic and aspartic acids: 'flipping' peptide charge states for characterization by positive ion mode ESI-MS.

    Science.gov (United States)

    Garapati, Sriramya; Burns, Colin S

    2014-03-01

    Use of the 4-pyridylmethyl ester group for side-chain protection of glutamic acid residues in solid-phase peptide synthesis enables switching of the charge state of a peptide from negative to positive, thus making detection by positive ion mode ESI-MS possible. The pyridylmethyl ester moiety is readily removed from peptides in high yield by hydrogenation. Combining the 4-pyridylmethyl ester protecting group with benzyl ester protection reduces the number of the former needed to produce a net positive charge and allows for purification by RP HPLC. This protecting group is useful in the synthesis of highly acidic peptide sequences, which are often beset by problems with purification by standard RP HPLC and characterization by ESI-MS. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  5. Novel organophosphorus compounds; synthesis, spectroscopy and X-ray crystallography

    Czech Academy of Sciences Publication Activity Database

    Shariatinia, Z.; Sohrabi, M.; Yousefi, M.; Kovaľ, Tomáš; Dušek, Michal

    2012-01-01

    Roč. 11, č. 2 (2012), s. 125-133 ISSN 1024-1221 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : organophosphorus compounds * NMR * X-ray crystallography * hydrogen bond Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.686, year: 2012

  6. The application of green chemistry methods in organophosphorus synthesis

    International Nuclear Information System (INIS)

    Odinets, Irina L; Matveeva, E V

    2012-01-01

    Data concerning the synthesis of organophosphorus compounds in ionic liquids, in water and under solvent-free conditions are considered and summarized. It is shown that this strategy, which complies with the definition of green chemistry, has advantages in terms of the rate of the process and the yields of target products as compared with syntheses in common organic solvents. The Wittig, Horner–Wadsworth–Emmons, Kabachnik–Fields, Arbuzov and Michaelis reactions are considered as examples. The bibliography includes 178 references.

  7. Rapid biodegradation of organophosphorus pesticides by Stenotrophomonas sp. G1

    International Nuclear Information System (INIS)

    Deng, Shuyan; Chen, Yao; Wang, Daosheng; Shi, Taozhong; Wu, Xiangwei; Ma, Xin; Li, Xiangqiong; Hua, Rimao; Tang, Xinyun; Li, Qing X.

    2015-01-01

    Highlights: • Stenotrophomonas sp. G1 was isolated from chlorpyrifos contaminated sludge. • Strain G1 is closest to Stenotrophomonas acidaminiphila. • Strain G1 can efficiently degrade 8 organophosphorus pesticides (OPs). • Intracellular methyl parathion hydrolase is responsible for the OP degradation. • Three factors were orthogonally optimized for degradation of methyl parathion. - Abstract: Organophosphorus insecticides have been widely used, which are highly poisonous and cause serious concerns over food safety and environmental pollution. A bacterial strain being capable of degrading O,O-dialkyl phosphorothioate and O,O-dialkyl phosphate insecticides, designated as G1, was isolated from sludge collected at the drain outlet of a chlorpyrifos manufacture plant. Physiological and biochemical characteristics and 16S rDNA gene sequence analysis suggested that strain G1 belongs to the genus Stenotrophomonas. At an initial concentration of 50 mg/L, strain G1 degraded 100% of methyl parathion, methyl paraoxon, diazinon, and phoxim, 95% of parathion, 63% of chlorpyrifos, 38% of profenofos, and 34% of triazophos in 24 h. Orthogonal experiments showed that the optimum conditions were an inoculum volume of 20% (v/v), a substrate concentration of 50 mg/L, and an incubation temperature in 40 °C. p-Nitrophenol was detected as the metabolite of methyl parathion, for which intracellular methyl parathion hydrolase was responsible. Strain G1 can efficiently degrade eight organophosphorus pesticides (OPs) and is a very excellent candidate for applications in OP pollution remediation

  8. Rapid biodegradation of organophosphorus pesticides by Stenotrophomonas sp. G1

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Shuyan; Chen, Yao [Key Laboratory of Agri-food Safety of Anhui Province, Lab of Quality & Safety and Risk Assessment for Agro-products on Storage and Preservation (Hefei), Ministry of Agriculture, School of Resource and Environment, Anhui Agricultural University, Hefei 230036 (China); Wang, Daosheng [School of Life Science, Anhui Agricultural University, Hefei 230036 (China); Shi, Taozhong; Wu, Xiangwei; Ma, Xin; Li, Xiangqiong [Key Laboratory of Agri-food Safety of Anhui Province, Lab of Quality & Safety and Risk Assessment for Agro-products on Storage and Preservation (Hefei), Ministry of Agriculture, School of Resource and Environment, Anhui Agricultural University, Hefei 230036 (China); Hua, Rimao, E-mail: rimaohua@ahau.edu.cn [Key Laboratory of Agri-food Safety of Anhui Province, Lab of Quality & Safety and Risk Assessment for Agro-products on Storage and Preservation (Hefei), Ministry of Agriculture, School of Resource and Environment, Anhui Agricultural University, Hefei 230036 (China); Tang, Xinyun [School of Life Science, Anhui Agricultural University, Hefei 230036 (China); Li, Qing X. [Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East–West Road, Honolulu, HI 957822 (United States)

    2015-10-30

    Highlights: • Stenotrophomonas sp. G1 was isolated from chlorpyrifos contaminated sludge. • Strain G1 is closest to Stenotrophomonas acidaminiphila. • Strain G1 can efficiently degrade 8 organophosphorus pesticides (OPs). • Intracellular methyl parathion hydrolase is responsible for the OP degradation. • Three factors were orthogonally optimized for degradation of methyl parathion. - Abstract: Organophosphorus insecticides have been widely used, which are highly poisonous and cause serious concerns over food safety and environmental pollution. A bacterial strain being capable of degrading O,O-dialkyl phosphorothioate and O,O-dialkyl phosphate insecticides, designated as G1, was isolated from sludge collected at the drain outlet of a chlorpyrifos manufacture plant. Physiological and biochemical characteristics and 16S rDNA gene sequence analysis suggested that strain G1 belongs to the genus Stenotrophomonas. At an initial concentration of 50 mg/L, strain G1 degraded 100% of methyl parathion, methyl paraoxon, diazinon, and phoxim, 95% of parathion, 63% of chlorpyrifos, 38% of profenofos, and 34% of triazophos in 24 h. Orthogonal experiments showed that the optimum conditions were an inoculum volume of 20% (v/v), a substrate concentration of 50 mg/L, and an incubation temperature in 40 °C. p-Nitrophenol was detected as the metabolite of methyl parathion, for which intracellular methyl parathion hydrolase was responsible. Strain G1 can efficiently degrade eight organophosphorus pesticides (OPs) and is a very excellent candidate for applications in OP pollution remediation.

  9. Optimization of Cholinesterase-Based Catalytic Bioscavengers Against Organophosphorus Agents.

    Science.gov (United States)

    Lushchekina, Sofya V; Schopfer, Lawrence M; Grigorenko, Bella L; Nemukhin, Alexander V; Varfolomeev, Sergei D; Lockridge, Oksana; Masson, Patrick

    2018-01-01

    Organophosphorus agents (OPs) are irreversible inhibitors of acetylcholinesterase (AChE). OP poisoning causes major cholinergic syndrome. Current medical counter-measures mitigate the acute effects but have limited action against OP-induced brain damage. Bioscavengers are appealing alternative therapeutic approach because they neutralize OPs in bloodstream before they reach physiological targets. First generation bioscavengers are stoichiometric bioscavengers. However, stoichiometric neutralization requires administration of huge doses of enzyme. Second generation bioscavengers are catalytic bioscavengers capable of detoxifying OPs with a turnover. High bimolecular rate constants ( k cat / K m > 10 6 M -1 min -1 ) are required, so that low enzyme doses can be administered. Cholinesterases (ChE) are attractive candidates because OPs are hemi-substrates. Moderate OP hydrolase (OPase) activity has been observed for certain natural ChEs and for G117H-based human BChE mutants made by site-directed mutagenesis. However, before mutated ChEs can become operational catalytic bioscavengers their dephosphylation rate constant must be increased by several orders of magnitude. New strategies for converting ChEs into fast OPase are based either on combinational approaches or on computer redesign of enzyme. The keystone for rational conversion of ChEs into OPases is to understand the reaction mechanisms with OPs. In the present work we propose that efficient OP hydrolysis can be achieved by re-designing the configuration of enzyme active center residues and by creating specific routes for attack of water molecules and proton transfer. Four directions for nucleophilic attack of water on phosphorus atom were defined. Changes must lead to a novel enzyme, wherein OP hydrolysis wins over competing aging reactions. Kinetic, crystallographic, and computational data have been accumulated that describe mechanisms of reactions involving ChEs. From these studies, it appears that introducing

  10. Optimization of Cholinesterase-Based Catalytic Bioscavengers Against Organophosphorus Agents

    Directory of Open Access Journals (Sweden)

    Sofya V. Lushchekina

    2018-03-01

    Full Text Available Organophosphorus agents (OPs are irreversible inhibitors of acetylcholinesterase (AChE. OP poisoning causes major cholinergic syndrome. Current medical counter-measures mitigate the acute effects but have limited action against OP-induced brain damage. Bioscavengers are appealing alternative therapeutic approach because they neutralize OPs in bloodstream before they reach physiological targets. First generation bioscavengers are stoichiometric bioscavengers. However, stoichiometric neutralization requires administration of huge doses of enzyme. Second generation bioscavengers are catalytic bioscavengers capable of detoxifying OPs with a turnover. High bimolecular rate constants (kcat/Km > 106 M−1min−1 are required, so that low enzyme doses can be administered. Cholinesterases (ChE are attractive candidates because OPs are hemi-substrates. Moderate OP hydrolase (OPase activity has been observed for certain natural ChEs and for G117H-based human BChE mutants made by site-directed mutagenesis. However, before mutated ChEs can become operational catalytic bioscavengers their dephosphylation rate constant must be increased by several orders of magnitude. New strategies for converting ChEs into fast OPase are based either on combinational approaches or on computer redesign of enzyme. The keystone for rational conversion of ChEs into OPases is to understand the reaction mechanisms with OPs. In the present work we propose that efficient OP hydrolysis can be achieved by re-designing the configuration of enzyme active center residues and by creating specific routes for attack of water molecules and proton transfer. Four directions for nucleophilic attack of water on phosphorus atom were defined. Changes must lead to a novel enzyme, wherein OP hydrolysis wins over competing aging reactions. Kinetic, crystallographic, and computational data have been accumulated that describe mechanisms of reactions involving ChEs. From these studies, it appears that

  11. Trace Detection of Organophosphorus Chemical Warfare Agents in Wastewater and Plants by Luminescent UIO-67(Hf) and Evaluating the Bioaccumulation of Organophosphorus Chemical Warfare Agents.

    Science.gov (United States)

    Lian, Xiao; Yan, Bing

    2018-05-02

    Organophosphorus chemical warfare agents (OPCWAs) are a group of organic pollutants characterized by high toxicity and chemical stability, and they are very difficult to be degraded. The trace quality of OPCWAs in water and food will cause great harm to the human body. Therefore, the detection of OPCWAs is a difficult challenge, which has become the research hotspot over the world. In this work, a Hf-based luminescent metal-organic framework (Eu@1) is prepared, and the reactivity of Hf 12 results in a methanephosphonic acid (MPA)-induced luminescence quenching and the charge transfer from MPA to Hf(IV) and generated exciplexes which are responsible for this quenching effect. The excellent performance of Eu@1 in the detection of MPA, with its finer selectivity, high sensitivity (LOD = 0.4 ppm), and large linear range (10 -7 to 10 -3 M), is encouraging for application in wastewater detection. Importantly, MPA is a pollutant that can be absorbed by plants and causes the bioaccumulation effect, and thus, the detection of MPA in real plant samples is a purposeful topic. Eu@1 also achieved satisfactory results in actual plant sample testing, and the bioaccumulation of MPA in onions, turnips, and cabbages is determined via our sensor. This fabricated detector provides a feasible path for the detection of ppm-level OPCWAs in a complex environment, which will help humans to avoid OPCWA-contaminated foods.

  12. Doubly versus Singly Positively Charged Oxygen Ions Back-Scattering from a Silicon Surface under Dynamic O2+ Bombardment

    Czech Academy of Sciences Publication Activity Database

    Franzreb, K.; Williams, P.; Lörinčík, Jan; Šroubek, Zdeněk

    203-204, 1/4 (2003), s. 39-42 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z2067918; CEZ:AV0Z4040901 Keywords : low-energy ion scattering * doubly charged ions * molecular orbital Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.284, year: 2003

  13. Accumulation and dissipation of positive charges induced on a PMMA build-up cap of an ionisation chamber by 60Co gamma-ray irradiation

    International Nuclear Information System (INIS)

    Morishita, Y.; Takata, N.

    2013-01-01

    The signal current from an ionisation chamber with a PMMA build-up cap decreases with irradiation time due to electric fields produced by positive charges induced on the cap. In the present study, it was confirmed that the signal current decreases faster for irradiation using narrower 60 Co gamma-ray beams. This is because the number of secondary electrons that are emitted from surrounding materials and penetrate the build-up cap is smaller in a narrower gamma-ray beam, so that fewer positive charges are neutralised. The ionisation chamber was first subjected to continuous gamma-ray irradiation for 24 h, following which it was irradiated with shorter periodic gamma-ray bursts while measuring the current signal. This allowed the coefficients of positive charge accumulation and dissipation to be determined. It was found that the dissipation coefficient has a large constant value during gamma-ray irradiation and decreases asymptotically to a small value after irradiation is stopped. From the coefficients, the minimum signal current was calculated, which is the value when accumulation and dissipation balance each other under continuous irradiation. The time required for the signal current to recover following irradiation was also calculated. (authors)

  14. Integrative Approach with Electrophysiological and Theoretical Methods Reveals a New Role of S4 Positively Charged Residues in PKD2L1 Channel Voltage-Sensing.

    Science.gov (United States)

    Numata, Tomohiro; Tsumoto, Kunichika; Yamada, Kazunori; Kurokawa, Tatsuki; Hirose, Shinichi; Nomura, Hideki; Kawano, Mitsuhiro; Kurachi, Yoshihisa; Inoue, Ryuji; Mori, Yasuo

    2017-08-29

    Numerical model-based simulations provide important insights into ion channel gating when experimental limitations exist. Here, a novel strategy combining numerical simulations with patch clamp experiments was used to investigate the net positive charges in the putative transmembrane segment 4 (S4) of the atypical, positively-shifted voltage-dependence of polycystic kidney disease 2-like 1 (PKD2L1) channel. Charge-neutralising mutations (K452Q, K455Q and K461Q) in S4 reduced gating charges, positively shifted the Boltzmann-type activation curve [i.e., open probability (P open )-V curve] and altered the time-courses of activation/deactivation of PKD2L1, indicating that this region constitutes part of a voltage sensor. Numerical reconstruction of wild-type (WT) and mutant PKD2L1-mediated currents necessitated, besides their voltage-dependent gating parameters, a scaling factor that describes the voltage-dependence of maximal conductance, G max . Subsequent single-channel conductance (γ) measurements revealed that voltage-dependence of G max in WT can be explained by the inward-rectifying property of γ, which is greatly changed in PKD2L1 mutants. Homology modelling based on PKD2 and Na V Ab structures suggest that such voltage dependence of P open and γ in PKD2L1 could both reflect the charged state of the S4 domain. The present conjunctive experimental and theoretical approaches provide a framework to explore the undetermined mechanism(s) regulating TRP channels that possess non-classical voltage-dependent properties.

  15. The brain imaging study of the organophosphorus pesticides poisoning

    International Nuclear Information System (INIS)

    Yang Yanmei; Liu Huaijun; Li Shuling; Wang Yongsheng; Huang Boyuan; Chi Cen; Shi Zhenyang; Cui Caixia; Zhou Lixia; Liu Runtian

    2004-01-01

    Objective: To summarize the CT and MR imaging findings in acute organophosphorus pesticides poisoning patients, and to improve the early diagnostic ability. Methods: The imaging of 34 patients of organophosphorus pesticides poisoning was analyzed, the poisons were all taken orally. The pesticides included methamidophos (12 cases), omethoate (15 cases), DDV (3 cases), and methylparathion (4 cases). According to the diagnosis and classification diagnosis criterion of acute organophosphorus pesticides poisoning, the patients were divided into two groups: mild or moderate grade group (24 cases) and severe grade group (10 cases). The relationship between the clinic grade and CT and MRI findings was studied. Results: in the severe grade group, 4 patients showed brain edema, presenting as sulcus and fissure flattened or disappeared, and ventricles and cisterns narrowed or closed 2-3 days after poisoning. In 3 patients 3 days to 3 months after poisoning, bilateral basal ganglion and cerebral cortex showed prolonged T 1 and T 2 signals, and high signal intensity was detected on FLAIR, and bilateral basal ganglion low density was revealed on CT. T 1 relaxation was shortened, T 2 WI and FLAIR imaging showed high signal intensity in 1 patient. The imaging of 1 patient 6 months after poisoning showed the cerebral sulcus, fissure and ventricle were enlarged. CT and MRI in the mild or moderate group were normal. By the Fisher's exact probabilities test, the imaging exhibition difference between the severe grade and mild or moderate grade patients was significant. Conclusion: The CT and MRI can reflect the brain injury after poisoning, and the imaging exhibitions were various. The imaging information can provide credible foundation for the therapy for lightening the brain edema and nourishing the brain cell

  16. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin

    2015-06-17

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  17. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin; Zhao, Kui; Fernandes, Nikhil J.; Boufflet, Pierre; Bannock, James Henry; Yu, Liyang; de Mello, John C; Stingelin, Natalie; Heeney, Martin; Giannelis, Emmanuel P.; Amassian, Aram

    2015-01-01

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  18. Multifunctional organophosphorus extractants: a status report on development and applications

    International Nuclear Information System (INIS)

    Schulz, W.W.; Horwitz, E.P.

    1988-01-01

    Up-to-date state of the development of science and technology of multifunctional organophosphorus extractants is considered. The detailed classification of these extractants is presented. They attracted pasticular interest because of affinity of some bifunctional phosphonates, phosphine oxides, carbamoylalkylphosphonates to trivalent Am, tetravalent and hexavalent actinides, trivalent lanthanides in strong mineral acids, and because of ability of some alkylpyrophosphoric acids to extract effectively U(4) from concentrated solutions of phosphoric acid. Application of these extractants for analytic purposes and in the field of nuclear technology is considered

  19. [Meta-analysis of association between organophosphorus pesticides and aplastic anemia].

    Science.gov (United States)

    Zhang, Ji; Yang, Tubao

    2015-09-01

    To evaluate the association between organophosphorus pesticides and aplastic anemia, and provide scientific evidence for the primary prevention of aplastic anemia. The published papers of case control studies on the association between organophosphorus pesticides and aplastic anemia from January 1990 to August 2014 were collected from Chinese BioMedical Literature Base (CBM), Chinese National Knowledge Infrastructure (CNKI), PubMed and EMBASE. The papers which met the inclusion criteria were evaluated. The pooled odds ratios (OR) and 95% confidence interval (CI) of organophosphorus pesticides were calculated with software Review Manager 5.0. Subgroup analysis were conducted for different population and different usage of organophosphorus pesticides. A total of 9 papers were selected, involving 5 833 subjects (1 404 cases and 4 429 controls). The results showed that organophosphorus pesticides could increase the risk of aplastic anemia (OR=1.97, 95% CI: 1.60-2.44) . Subgroup analysis showed that Asian (OR=2.01, 95% CI: 1.52-2.66) had higher risk of aplastic anemia than American or European (OR=1.93, 95% CI: 1.39-2.67) . Using pure organophosphorus pesticides (OR=2.15, 95% CI: 1.60-2.88) was more prone to cause aplastic anemia than using the mixture of organophosphorus pesticides (OR=1.82, 95% CI: 1.34-2.47). The analysis indicated that organophosphorus pesticides might be a risk factor for aplastic anemia. Reducing organophosphorus pesticides exposure in daily life and industrial or agricultural production could prevent the incidence of aplastic anemia.

  20. Acute myocardial infarction: Can it be a complication of acute organophosphorus compound poisoning?

    Directory of Open Access Journals (Sweden)

    P Joshi

    2013-01-01

    Full Text Available Organophosphorus compounds are used as pesticides and represent a common cause of poisoning in developing countries including India due to their widespread availability and use. Toxicity due to these agents can affect many organs including heart. Here, we report a case of acute organophosphorus poisoning (parathion, followed by acute myocardial infarction; documented by clinical features, electrocardiographic changes, and elevated cardiac enzymes. Myocardial infarction has been rarely reported with organophosphorus compounds exposure, thus awareness of this complication can reduce morbidity and mortality.

  1. Bounds on the g/sub K//sub N//sub Σ/ 2 coupling constant from positivity and charge-exchange data

    International Nuclear Information System (INIS)

    Antolin, J.

    1987-01-01

    Positivity of the imaginary part of the forward K - n elastic amplitude on the unphysical cut allows the calculation of bounds on the g/sub K//sub N//sub Σ/ 2 coupling constant using the forward differential cross sections of the charge-exchange reaction K - p→K-bar 0 n, the scarce K - n real-part data, and a Stieltjes parametrization of the K - p real-part data. The bounds on the coupling constant are 2.11 2 - n amplitude: (0.35 +- 0.05) +- (0.16 +- 0.04)i GeV/c

  2. Doubly versus singly positively charged oxygen ions back-scattered from a silicon surface under dynamic O2+ bombardment

    International Nuclear Information System (INIS)

    Franzreb, Klaus; Williams, Peter; Loerincik, Jan; Sroubek, Zdenek

    2003-01-01

    Mass-resolved (and emission-charge-state-resolved) low-energy ion back-scattering during dynamic O 2 + bombardment of a silicon surface was applied in a Cameca IMS-3f secondary ion mass spectrometry (SIMS) instrument to determine the bombarding energy dependence of the ratio of back-scattered O 2+ versus O + . While the ratio of O 2+ versus O + drops significantly at reduced bombarding energies, O 2+ back-scattered from silicon was still detectable at an impact energy (in the lab frame) as low as about 1.6 keV per oxygen atom. Assuming neutralization prior to impact, O 2+ ion formation in an asymmetric 16 O→ 28 Si collision is expected to take place via 'collisional double ionization' (i.e. by promotion of two outer O 2p electrons) rather than by the production of an inner-shell (O 2s or O 1s) core hole followed by Auger-type de-excitation during or after ejection. A molecular orbital (MO) correlation diagram calculated for a binary 'head-on' O-Si collision supports this interpretation

  3. Hard X-ray polarimetry with position sensitve germanium detectors. Studies of the recombination transitions into highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Tashenov, Stanislav

    2005-07-01

    In this work a first study of the photon polarization for the process of radiative recombination has been performed. This was done at the ESR storage ring at GSI for uranium ions colliding with N2 at various collision energies. For this measurement a high purity Ge Pixel Detector with a 4 x 4 segmentation matrix was applied. The investigation was performed at the Gas-jet target of the ESR. The detector was placed at 60 and 90 observation angles. The sensitivity of the Compton scattering effect to the linear polarization of the X-Ray radiation was employed for the polarization measurement. Detailed investigations of the scattering and geometrical effects inside the detector were performed in order to develop a method to interpret the experimental data and extract the degree of the linear polarization in the hard X-Ray regime with a high precision. A special emphasis was given to the geometry of the detector and it's influence on the measured pixel-to-pixel Compton scattering intensities. The developed method enabled to achieve a precision of the order of 10% with the Pixel Detector which is dominated by the statistical uncertainties. The obtained results show a good agreement with the theoretical values derived from the exact relativistic calculations. For the case of the linear polarization of the K-REC photons, the measured data con rm the theoretical prediction that strong depolarization effects occur for high projectile charges in the forward hemisphere. The latter is in disagreement with the nonrelativistic theory which predicts a 100 % polarization regardless of the emission angle. (orig.)

  4. Hard X-ray polarimetry with position sensitve germanium detectors. Studies of the recombination transitions into highly charged ions

    International Nuclear Information System (INIS)

    Tashenov, Stanislav

    2005-01-01

    In this work a first study of the photon polarization for the process of radiative recombination has been performed. This was done at the ESR storage ring at GSI for uranium ions colliding with N2 at various collision energies. For this measurement a high purity Ge Pixel Detector with a 4 x 4 segmentation matrix was applied. The investigation was performed at the Gas-jet target of the ESR. The detector was placed at 60 and 90 observation angles. The sensitivity of the Compton scattering effect to the linear polarization of the X-Ray radiation was employed for the polarization measurement. Detailed investigations of the scattering and geometrical effects inside the detector were performed in order to develop a method to interpret the experimental data and extract the degree of the linear polarization in the hard X-Ray regime with a high precision. A special emphasis was given to the geometry of the detector and it's influence on the measured pixel-to-pixel Compton scattering intensities. The developed method enabled to achieve a precision of the order of 10% with the Pixel Detector which is dominated by the statistical uncertainties. The obtained results show a good agreement with the theoretical values derived from the exact relativistic calculations. For the case of the linear polarization of the K-REC photons, the measured data con rm the theoretical prediction that strong depolarization effects occur for high projectile charges in the forward hemisphere. The latter is in disagreement with the nonrelativistic theory which predicts a 100 % polarization regardless of the emission angle. (orig.)

  5. The infra-red spectrum of the molecular dication (doubly positively charged molecule) D35Cl2+

    International Nuclear Information System (INIS)

    Abusen, R.A.

    1999-07-01

    The ion-beam/laser-beam spectrometer used in this work was designed, built and commissioned for the experimental investigation of doubly charged molecular species [Shiell 1995]. Using this spectrometer the photodissociation spectrum of the X 3 Σ - state of the molecular dication D 35 Cl 2+ was measured in the infrared. It has not yet been possible to assign and fit the observed transitions in the usual way, but comparisons of our spectra with ab-initio generated spectra show good agreement and form the basis for our preliminary assignments. Our preliminary analysis shows a good agreement between the measured spectra and an ab-initio theoretical spectra of the ν = 2-1 band, including the rotational constants and tunneling lifetimes, calculated from the potential energy of Bennett and McNab [1995]. The theoretical spectrum was brought into agreement with the measured spectra by moving its band origin by -21.1 cm -1 . The theoretical rotational constants that give good agreement with the spectrum are (in cm -1 ) B'' = 3.898, D'' = 3.561, H'' = 1.04 x 10 -9 , B' = 3.648, D' = 3.163 x 10 -4 , H' = -9.269 x 10 -8 . The shifted origin of the ν = 2-1 band is 994.3 cm -1 . A Fortran computer program was written to simulate 3Σ-3Σ vibration-rotation spectra. The theoretical spectrum obtained with this computer program has been compared with our measured spectrum. Our experimentally measured line widths and wavenumbers have been compared with the ab-initio theoretical spectrum and a good agreement obtained. This is good evidence that we are observing the ν=2-1 band of D 35 CI 2+ in the ground electronic state (X 3 Σ - state). Good agreement between measured and predicted hyperfine patterns was found using a Fermi contact constant (for the chlorine nucleus) of 190 MHz. (author)

  6. The effect of desulfation of chondroitin sulfate on interactions with positively charged growth factors and upregulation of cartilaginous markers in encapsulated MSCs.

    Science.gov (United States)

    Lim, Jeremy J; Temenoff, Johnna S

    2013-07-01

    Sulfated glycosaminoglycans (GAGs) are known to interact electrostatically with positively charged growth factors to modulate signaling. Therefore, regulating the degree of sulfation of GAGs may be a promising approach to tailor biomaterial carriers for controlled growth factor delivery and release. For this study, chondroitin sulfate (CS) was first desulfated to form chondroitin, and resulting crosslinked CS and chondroitin hydrogels were examined in vitro for release of positively charged model protein (histone) and for their effect on cartilaginous differentiation of encapsulated human mesenchymal stem cells (MSCs). Desulfation significantly increased the release of histone from chondroitin hydrogels (30.6 ± 2.3 μg released over 8 days, compared to natively sulfated CS with 20.2 ± 0.8 μg), suggesting that sulfation alone plays a significant role in modulating protein interactions with GAG hydrogels. MSCs in chondroitin hydrogels significantly upregulated gene expression of collagen II and aggrecan by day 21 in chondrogenic medium (115 ± 100 and 23.1 ± 7.9 fold upregulation of collagen II and aggrecan, respectively), compared to CS hydrogels and PEG-based swelling controls, indicating that desulfation may actually enhance the response of MSCs to soluble chondrogenic cues, such as TGF-β1. Thus, desulfated chondroitin materials present a promising biomaterial tool to further investigate electrostatic GAG/growth factor interactions, especially for repair of cartilaginous tissues. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Levels of organophosphorus pesticides in medicinal plants commonly consumed in Iran

    Directory of Open Access Journals (Sweden)

    Sarkhail Parisa

    2012-08-01

    Full Text Available Abstract The frequent occurrence of pesticide residues in herbal materials was indicated by previous studies. In this study, the concentration of some of the organophosphorus pesticides including parathion, malathion, diazinon and pirimiphos methyl in different kinds of medicinal plants were determined. The samples were collected randomly from ten local markets of different areas of Iran. At the detection limit of 0.5 ng g-1, parathion and pirimiphos methyl were not detected in any of the samples. Some amounts of malathion and diazinon were found in Zataria, Matricaria chamomile, Spearmint and Cumin Seed samples while, the concentrations of target organophosphorus pesticides in Borage samples were below the detection limits of the methods which could be a result of intensive transformation of organophosphorus pesticides by Borage. In addition the organophosphorus pesticides were detected in all of the samples below the maximum residue levels (MRLs proposed by the international organizations.

  8. UPTAKE AND PHYTOTRANSFORMATION OF ORGANOPHOSPHORUS PESTICIDES BY AXENICALLY CULTIVATED AQUATIC PLANTS

    Science.gov (United States)

    The uptake and phytotransformation of organophosphorus (OP) pesticides (malathion, demeton-S-methyl, and crufomate) was investigated in vitro using the axenically aquatic cultivated plants parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza L.), and elodea (E...

  9. Surface Chemistry of Enzymes for Detection and Decontamination of Organophosphorus Compounds

    National Research Council Canada - National Science Library

    Leblanc, Roger

    2003-01-01

    ...), organophosphorus acid hydrolase (OPH), and covalent bonding of the enzyme onto the substrate. Results are encouraging and the studied enzymes form stable monolayers at the interface and can be transferred on to the solid substrate...

  10. Modulation of Immune Response by Organophosphorus Pesticides: Fishes as a Potential Model in Immunotoxicology

    Science.gov (United States)

    Díaz-Resendiz, K. J. G.; Toledo-Ibarra, G. A.; Girón-Pérez, M. I.

    2015-01-01

    Immune response is modulated by different substances that are present in the environment. Nevertheless, some of these may cause an immunotoxic effect. In this paper, the effect of organophosphorus pesticides (frequent substances spilled in aquatic ecosystems) on the immune system of fishes and in immunotoxicology is reviewed. Furthermore, some cellular and molecular mechanisms that might be involved in immunoregulation mechanisms of organophosphorus pesticides are discussed. PMID:25973431

  11. Modulation of Immune Response by Organophosphorus Pesticides: Fishes as a Potential Model in Immunotoxicology

    Directory of Open Access Journals (Sweden)

    K. J. G. Díaz-Resendiz

    2015-01-01

    Full Text Available Immune response is modulated by different substances that are present in the environment. Nevertheless, some of these may cause an immunotoxic effect. In this paper, the effect of organophosphorus pesticides (frequent substances spilled in aquatic ecosystems on the immune system of fishes and in immunotoxicology is reviewed. Furthermore, some cellular and molecular mechanisms that might be involved in immunoregulation mechanisms of organophosphorus pesticides are discussed.

  12. Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea

    International Nuclear Information System (INIS)

    Moeller, Axel; Xie Zhiyong; Caba, Armando; Sturm, Renate; Ebinghaus, Ralf

    2011-01-01

    Air samples collected in the German part of the North Sea from March to July 2010 were investigated for organophosphorus compounds (OPs) being applied as flame retardants and plasticizers. The Σ 8 OPs concentration ranged from 110 to 1400 pg m -3 while tris(2-chloroisopropyl) phosphate (TCPP) dominated all samples with individual concentrations up to 1200 pg m -3 . The highest concentrations were observed in continental air masses showing the high influence of industrialized regions including production sites on atmospheric emissions and concentrations. The occurrence of OPs even in oceanic/Arctic air masses shows that OPs can undergo long-range atmospheric transport. Dry particle-bound deposition fluxes from 9 to 240 ng m -2 d -1 for Σ 8 OPs were estimated leading to a minimum annual flux of 710 ± 580 kg y -1 OPs into the German North Sea. This study presents the first occurrence of OPs in the marine atmosphere together with important information on their long-range transport potential. - Highlights: → Organophosphorus flame retardants are detected for the first time in the marine atmosphere. → Organophosphorus compounds can undergo medium to long-range atmospheric transport. → Western Europe emits organophosphorus compounds to the marine atmosphere. → Marine air levels of organophosphorus flame retardants range up to 1 ng/m 3 . - Organophosphorus flame retardants, in particular tris(2-chloroisopropyl) phosphate, are emitted into the North Sea atmosphere by Western European countries.

  13. Determination of organophosphorus pesticide residues in tomatoes by gas chromatography

    International Nuclear Information System (INIS)

    Souissi, Sihem

    2010-01-01

    Chloropyriphos and malathion are two organophosphorus pesticides from many others pesticides widely used by famers in agriculture .Because of their bad effect on human health, officials standards are set by the international organisations and communities to ensure safer food for consumer .In the same way, scientists over the world are working hard to develop new detection techniques responding to the international requirements. In this study, an ' IAEA-ethylacetate method ', an adaptation of the popular QuEChERS multi residue method, was optimized to analyse chloropyriphos and Malathion residues in tomatoes .Ethyl-Acetate was used as an extraction solvent the PSA was kept for the clean up procedure. GC-NPD is used for samples analysis .The method optimized is specifique, selective with a recovery averaged more than 70 pour cent. A complete validation of the method is necessary to be used for routine analysis.

  14. Fluorescent Chemosensors for Toxic Organophosphorus Pesticides: A Review

    Directory of Open Access Journals (Sweden)

    Kenneth Fletcher

    2010-07-01

    Full Text Available Many organophosphorus (OP based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.

  15. Novel use of positively charged nylon transfer membranes for trapping indoleacetic acid or other small anions during efflux from plant tissues

    Science.gov (United States)

    Evans, M. L.; Hangarter, R. P.

    1993-01-01

    Positively charged nylon blotting membranes were used as an anion binding medium to trap [14C]indoleactic acid (IAA) as it exited cells at the basal ends of Coleus blumei L. stem and Zea mays L. coleoptile segments. Autoradiography was used to visualize where the [14C] that moved out of the cut ends was localized on the nylon membrane. Diffusion of [14C]IAA from the initial point of contact with the nylon membrane was minimal. Comparison of the autoradiograms with anatomical tissue prints of the cut ends of the segments was used to determine what tissues participate in IAA movement. The results of these initial studies were consistent with other reports suggesting that [14C]IAA movement was primarily associated with vascular tissues in both C. blumei stems and corn coleoptiles, but the resolution was not sufficient to identify which vascular tissues were involved in IAA transport. With further refinements, this technique could also be used for studying the movement of other small charged molecules through plant tissues.

  16. Interaction of cationic porphyrins with DNA: Importance of the number and position of the charges and minimum structural requirements for intercalation

    International Nuclear Information System (INIS)

    Sari, M.A.; Battioni, J.P.; Dupre, D.; Mansuy, D.; Le Pecq, J.B.

    1990-01-01

    Thirty-three porphyrins or metalloporphyrins corresponding to the general formula [meso-[N-methyl-4(or 3 or 2)-pyridiniumyl] n (aryl) 4-n porphyrin]M (M = H 2 , Cu II , or ClFe III ), with n = 2-4, have been synthesized and characterized by UV-visible and 1 H NMR spectroscopy and mass spectrometry. These porphyrins differ not only in the number (2-4) and position of their cationic charges but also in the steric requirements to reach even temporarily a completely planar geometry. Interaction of these porphyrins or metalloporphyrins with calf thymus DNA has been studied and their apparent affinity binding constants have been determined by use of a competition method with ethidium bromide which was applicable not only for all the free base porphyrins but also for their copper (II) or iron (III) complexes. Whatever their mode of binding may be, their apparent affinity binding constants were relatively high and a linear decrease of log K app with the number of porphyrin charges was observed. Studies of porphyrin-DNA interactions by UV and fluorescence spectroscopy, viscosimetry, and fluorescence energy transfer experiments showed that not only the tetracationic meso-tetrakis[N-methyl-4(or 3)-pyridiniumyl]porphyrins, which both involved four freely rotating meso-aryl groups, but also the corresponding tri- and dicationic porphyrins were able to intercalate into calf thymus DNA. These results show that only half of the porphyrin ring is necessary for intercalation to occur

  17. Impact of the interaction with the positive charge in adsorption of benzene and other organic compounds from aqueous solutions on carbons

    Science.gov (United States)

    Terzyk, Artur P.; Ćwiertnia, Magdalena S.; Wiśniewski, Marek; Gauden, Piotr A.; Rychlicki, Gerhard; Szymański, Grzegorz S.

    2007-02-01

    We present the results of benzene adsorption at the acidic pH level determined on the series of chemically modified activated carbons and at three temperatures. The influence of carbon surface chemical composition on benzene adsorption is discussed. It is shown that the decrease in the pH level from 7 up to 1.5 increases benzene adsorption and the only exception is carbon modified with gaseous ammonia. Basing on the results of current work and those published previously (for phenol, paracetamol, acetanilide and aniline) and using the results of quantum chemistry calculations (DFT, Gaussian 98) we show, that the value of the energy of interaction with unit positive charge is crucial during the analysis of the influence of pH level on adsorption. Obtained results allow to predict the changes in adsorption of aromatics on carbons with the decrease in the pH level.

  18. Modulational instability of ultra-low-frequency shear dust Alfvén waves in a plasma medium of positive and negatively charged dust fluids

    International Nuclear Information System (INIS)

    Mamun, A. A.

    2014-01-01

    The propagation of finite amplitude ultra-low-frequency shear dust Alfvén (SDA) waves, and their modulational instability in a magnetized plasma medium of positive and negatively charged dust fluids have been theoretically investigated by using the reductive perturbation method. The derivative nonlinear Schrödinger equation is derived to examine the stability analysis of such SDA waves. It is found that the SDA waves propagating in such an opposite polarity dust plasma medium are modulationally unstable, and that the instability criterion and the growth rate of these unstable SDA waves in such a novel opposite polarity dust plasma medium are found to be significantly different from those in electron–ion or electron–positron plasma media. The implications of the present investigation in different space environments and laboratory devices are briefly discussed.

  19. A zeta potential value determines the aggregate's size of penta-substituted [60]fullerene derivatives in aqueous suspension whereas positive charge is required for toxicity against bacterial cells.

    Science.gov (United States)

    Deryabin, Dmitry G; Efremova, Ludmila V; Vasilchenko, Alexey S; Saidakova, Evgeniya V; Sizova, Elena A; Troshin, Pavel A; Zhilenkov, Alexander V; Khakina, Ekaterina A; Khakina, Ekaterina E

    2015-08-08

    The cause-effect relationships between physicochemical properties of amphiphilic [60]fullerene derivatives and their toxicity against bacterial cells have not yet been clarified. In this study, we report how the differences in the chemical structure of organic addends in 10 originally synthesized penta-substituted [60]fullerene derivatives modulate their zeta potential and aggregate's size in salt-free and salt-added aqueous suspensions as well as how these physicochemical characteristics affect the bioenergetics of freshwater Escherichia coli and marine Photobacterium phosphoreum bacteria. Dynamic light scattering, laser Doppler micro-electrophoresis, agarose gel electrophoresis, atomic force microscopy, and bioluminescence inhibition assay were used to characterize the fullerene aggregation behavior in aqueous solution and their interaction with the bacterial cell surface, following zeta potential changes and toxic effects. Dynamic light scattering results indicated the formation of self-assembled [60]fullerene aggregates in aqueous suspensions. The measurement of the zeta potential of the particles revealed that they have different surface charges. The relationship between these physicochemical characteristics was presented as an exponential regression that correctly described the dependence of the aggregate's size of penta-substituted [60]fullerene derivatives in salt-free aqueous suspension from zeta potential value. The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds. A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity. Atomic force microscopy data suggested that the

  20. Gas chromatography with flame photometric detection of 31 organophosphorus pesticide residues in Alpinia oxyphylla dried fruits.

    Science.gov (United States)

    Zhao, Xiangsheng; Kong, Weijun; Wei, Jianhe; Yang, Meihua

    2014-11-01

    A simple, rapid and effective gas chromatography-flame photometric detection method was established for simultaneous multi-component determination of 31 organophosphorus pesticides (OPPs) residues in Alpinia oxyphylla, which is widely consumed as a traditional medicine and food in China. Sample preparation was completed in a single step without any clean-up procedure. All pesticides expressed good linear relationships between 0.004 and 1.0 μg/mL with correlation coefficients higher than 0.9973. The method gave satisfactory recoveries for most pesticides. The limits of detection varied from 1 to 10 ng/mL, and the limits of quantification (LOQs) were between 4 and 30 ng/mL. The proposed method was successfully applied to 55 commercial samples purchased from five different areas. Five pesticide residues were detected in four (7.27%) samples. The positive samples were confirmed by gas chromatography with tandem mass spectrometry (GC-MS/MS). Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Organophosphorus esters in the oceans and possible relation with ocean gyres

    International Nuclear Information System (INIS)

    Cheng, Wenhan; Xie, Zhouqing; Blais, Jules M.; Zhang, Pengfei; Li, Ming; Yang, Chengyun; Huang, Wen; Ding, Rui; Sun, Liguang

    2013-01-01

    Four organophosphorus esters (OPEs) were detected in aerosol samples collected in the West Pacific, the Indian Ocean and the Southern Ocean from 2009 to 2010, suggesting their circumpolar and global distribution. In general, the highest concentrations were detected near populated regions in China, Australia and New Zealand. OPE concentrations in the Southern Ocean were about two orders of magnitude lower than those near major continents. Additionally, relatively high OPE concentrations were detected at the Antarctic Peninsula, where several scientific survey stations are located. The four OPEs investigated here are significantly correlated with each other, suggesting they may derive from the same source. In the circumpolar transect, OPE concentrations were associated with ocean gyres in the open ocean. Their concentrations were positively related with average vorticity in the sampling area suggesting that a major source of OPEs may be found in ocean gyres where plastic debris is known to accumulate. -- Highlights: •We provide OPE concentrations in aerosols in a circumpolar expedition. •We find strong anthropogenic source of OPE pollution. •We suggest potential relationship between ocean gyres and OPE pollution. -- Our work provides a circumpolar investigation on OPEs in the Southern Ocean and we suggest a possibility that ocean currents and gyres may act as important roles in global transport of OPEs

  2. Determinants of Organophosphorus Pesticide Urinary Metabolite Levels in Young Children Living in an Agricultural Community

    Directory of Open Access Journals (Sweden)

    Brenda Eskenazi

    2011-04-01

    Full Text Available Organophosphorus (OP pesticides are used in agriculture and several are registered for home use. As young children age they may experience different pesticide exposures due to varying diet, behavior, and other factors. We measured six OP dialkylphosphate (DAP metabolites (three dimethyl alkylphosphates (DMAP and three diethyl alkylphosphates (DEAP in urine samples collected from ~400 children living in an agricultural community when they were 6, 12, and 24 months old. We examined bivariate associations between DAP metabolite levels and determinants such as age, diet, season, and parent occupation. To evaluate independent impacts, we then used generalized linear mixed multivariable models including interaction terms with age. The final models indicated that DMAP metabolite levels increased with age. DMAP levels were also positively associated with daily servings of produce at 6- and 24-months. Among the 6-month olds, DMAP metabolite levels were higher when samples were collected during the summer/spring versus the winter/fall months. Among the 12-month olds, DMAP and DEAP metabolites were higher when children lived ≤60 meters from an agricultural field. Among the 24-month-olds, DEAP metabolite levels were higher during the summer/spring months. Our findings suggest that there are multiple determinants of OP pesticide exposures, notably dietary intake and temporal and spatial proximity to agricultural use. The impact of these determinants varied by age and class of DAP metabolite.

  3. Label-Free Platform for MicroRNA Detection Based on the Fluorescence Quenching of Positively Charged Gold Nanoparticles to Silver Nanoclusters.

    Science.gov (United States)

    Miao, Xiangmin; Cheng, Zhiyuan; Ma, Haiyan; Li, Zongbing; Xue, Ning; Wang, Po

    2018-01-16

    A novel strategy was developed for microRNA-155 (miRNA-155) detection based on the fluorescence quenching of positively charged gold nanoparticles [(+)AuNPs] to Ag nanoclusters (AgNCs). In the designed system, DNA-stabilized Ag nanoclusters (DNA/AgNCs) were introduced as fluorescent probes, and DNA-RNA heteroduplexes were formed upon the addition of target miRNA-155. Meanwhile, the (+)AuNPs could be electrostatically adsorbed on the negatively charged single-stranded DNA (ssDNA) or DNA-RNA heteroduplexes to quench the fluorescence signal. In the presence of duplex-specific nuclease (DSN), DNA-RNA heteroduplexes became a substrate for the enzymatic hydrolysis of the DNA strand to yield a fluorescence signal due to the diffusion of AgNCs away from (+)AuNPs. Under the optimal conditions, (+)AuNPs displayed very high quenching efficiency to AgNCs, which paved the way for ultrasensitive detection with a low detection limit of 33.4 fM. In particular, the present strategy demonstrated excellent specificity and selectivity toward the detection of target miRNA against control miRNAs, including mutated miRNA-155, miRNA-21, miRNA-141, let-7a, and miRNA-182. Moreover, the practical application value of the system was confirmed by the evaluation of the expression levels of miRNA-155 in clinical serum samples with satisfactory results, suggesting that the proposed sensing platform is promising for applications in disease diagnosis as well as the fundamental research of biochemistry.

  4. The electron trap parameter extraction-based investigation of the relationship between charge trapping and activation energy in IGZO TFTs under positive bias temperature stress

    Science.gov (United States)

    Rhee, Jihyun; Choi, Sungju; Kang, Hara; Kim, Jae-Young; Ko, Daehyun; Ahn, Geumho; Jung, Haesun; Choi, Sung-Jin; Myong Kim, Dong; Kim, Dae Hwan

    2018-02-01

    Experimental extraction of the electron trap parameters which are associated with charge trapping into gate insulators under the positive bias temperature stress (PBTS) is proposed and demonstrated for the first time in amorphous indium-gallium-zinc-oxide thin-film transistors. This was done by combining the PBTS/recovery time-evolution of the experimentally decomposed threshold voltage shift (ΔVT) and the technology computer-aided design (TCAD)-based charge trapping simulation. The extracted parameters were the trap density (NOT) = 2.6 × 1018 cm-3, the trap energy level (ΔET) = 0.6 eV, and the capture cross section (σ0) = 3 × 10-19 cm2. Furthermore, based on the established TCAD framework, the relationship between the electron trap parameters and the activation energy (Ea) is comprehensively investigated. It is found that Ea increases with an increase in σ0, whereas Ea is independent of NOT. In addition, as ΔET increases, Ea decreases in the electron trapping-dominant regime (low ΔET) and increases again in the Poole-Frenkel (PF) emission/hopping-dominant regime (high ΔET). Moreover, our results suggest that the cross-over ΔET point originates from the complicated temperature-dependent competition between the capture rate and the emission rate. The PBTS bias dependence of the relationship between Ea and ΔET suggests that the electric field dependence of the PF emission-based electron hopping is stronger than that of the thermionic field emission-based electron trapping.

  5. Simultaneous determination of organophosphorus pesticides in fruits and vegetables using atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    Cheng, Zhipeng; Dong, Fengshou; Xu, Jun; Liu, Xingang; Wu, Xiaohu; Chen, Zenglong; Pan, Xinglu; Gan, Jay; Zheng, Yongquan

    2017-09-15

    This paper describes the application of atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry for the simultaneous determination of organophosphorus pesticides in apple, pear, tomato, cucumber and cabbage. Soft ionization with atmospheric pressure ionization source was compared with traditional electron impact ionization (EI). The sensitivity of GC coupled to atmospheric pressure ionization (APGC) for all the analytes was enhanced by 1.0-8.2 times. The ionization modes with atmospheric pressure ionization source was studied by comparing the charge-transfer and proton-transfer conditions. The optimized QuEChERs method was used to pretreat the samples. The calibration curves were found linear from 10 to 1000μg/L, obtaining correlation coefficients higher than 0.9845. Satisfactory mean recovery values, in the range of 70.0-115.9%, and satisfactory precision, with all RSD r <19.7% and all RSD R values <19.5% at the three fortified concentration levels for all the fifteen OPPs. The results demonstrate the potential of APGC-QTOF-MS for routine quantitative analysis of organophosphorus pesticide in fruits and vegetables. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Charged particle detector

    International Nuclear Information System (INIS)

    Hagen, R.D.

    1975-01-01

    A device for detecting the emission of charged particles from a specimen is described. The specimen is placed within an accumulator means which statically accumulates any charged particles emitted from the specimen. The accumulator means is pivotally positioned between a first capacitor plate having a positive electrical charge and a second capacitor plate having a negative electrical charge. The accumulator means is attracted to one capacitor plate and repelled from the other capacitor plate by an amount proportional to the amount and intensity of charged particles emitted by the specimen. (auth)

  7. Clinical emergency treatment of 68 critical patients with severe organophosphorus poisoning and prognosis analysis after rescue.

    Science.gov (United States)

    Dong, Hui; Weng, Yi-Bing; Zhen, Gen-Shen; Li, Feng-Jie; Jin, Ai-Chun; Liu, Jie

    2017-06-01

    This study reports the clinical emergency treatment of 68 critical patients with severe organophosphorus poisoning, and analyzes the prognosis after rescue.The general data of 68 patients with severe organophosphorus poisoning treated in our hospital were retrospectively analyzed. These patients were divided into 2 groups: treatment group, and control group. Patients in the control group received routine emergency treatment, while patients in the treatment group additionally received hemoperfusion plus hemodialysis on the basis of routine emergency treatment. The curative effects in these 2 groups and the prognosis after rescue were compared.Compared with the control group, atropinization time, recovery time of cholinesterase activity, recovery time of consciousness, extubation time, and length of hospital stay were shorter (P poisoning rebound rate was significantly lower (P treatment group.Hemoperfusion and hemodialysis on the basis of routine emergency treatment for critical patients with organophosphorus poisoning can improve rescue outcomes and improve the prognosis of patients, which should be popularized.

  8. Organophosphorus reagents in actinide separations: Unique tools for production, cleanup and disposal

    International Nuclear Information System (INIS)

    Nash, K. L.

    2000-01-01

    Interactions of actinide ions with phosphate and organophosphorus reagents have figured prominently in nuclear science and technology, particularly in the hydrometallurgical processing of irradiated nuclear fuel. Actinide interactions with phosphorus-containing species impact all aspects from the stability of naturally occurring actinides in phosphate mineral phases through the application of the bismuth phosphate and PUREX processes for large-scale production of transuranic elements to the development of analytical separation and environment restoration processes based on new organophosphorus reagents. In this report, an overview of the unique role of organophosphorus compounds in actinide production, disposal, and environment restoration is presented. The broad utility of these reagents and their unique chemical properties is emphasized

  9. A systems-level approach for investigating organophosphorus pesticide toxicity.

    Science.gov (United States)

    Zhu, Jingbo; Wang, Jing; Ding, Yan; Liu, Baoyue; Xiao, Wei

    2018-03-01

    The full understanding of the single and joint toxicity of a variety of organophosphorus (OP) pesticides is still unavailable, because of the extreme complex mechanism of action. This study established a systems-level approach based on systems toxicology to investigate OP pesticide toxicity by incorporating ADME/T properties, protein prediction, and network and pathway analysis. The results showed that most OP pesticides are highly toxic according to the ADME/T parameters, and can interact with significant receptor proteins to cooperatively lead to various diseases by the established OP pesticide -protein and protein-disease networks. Furthermore, the studies that multiple OP pesticides potentially act on the same receptor proteins and/or the functionally diverse proteins explained that multiple OP pesticides could mutually enhance toxicological synergy or additive on a molecular/systematic level. To the end, the integrated pathways revealed the mechanism of toxicity of the interaction of OP pesticides and elucidated the pathogenesis induced by OP pesticides. This study demonstrates a systems-level approach for investigating OP pesticide toxicity that can be further applied to risk assessments of various toxins, which is of significant interest to food security and environmental protection. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Detection of Organophosphorus Pesticides with Colorimetry and Computer Image Analysis.

    Science.gov (United States)

    Li, Yanjie; Hou, Changjun; Lei, Jincan; Deng, Bo; Huang, Jing; Yang, Mei

    2016-01-01

    Organophosphorus pesticides (OPs) represent a very important class of pesticides that are widely used in agriculture because of their relatively high-performance and moderate environmental persistence, hence the sensitive and specific detection of OPs is highly significant. Based on the inhibitory effect of acetylcholinesterase (AChE) induced by inhibitors, including OPs and carbamates, a colorimetric analysis was used for detection of OPs with computer image analysis of color density in CMYK (cyan, magenta, yellow and black) color space and non-linear modeling. The results showed that there was a gradually weakened trend of yellow intensity with the increase of the concentration of dichlorvos. The quantitative analysis of dichlorvos was achieved by Artificial Neural Network (ANN) modeling, and the results showed that the established model had a good predictive ability between training sets and predictive sets. Real cabbage samples containing dichlorvos were detected by colorimetry and gas chromatography (GC), respectively. The results showed that there was no significant difference between colorimetry and GC (P > 0.05). The experiments of accuracy, precision and repeatability revealed good performance for detection of OPs. AChE can also be inhibited by carbamates, and therefore this method has potential applications in real samples for OPs and carbamates because of high selectivity and sensitivity.

  11. Plutonium and americium extraction studies with bifunctional organophosphorus extractants

    International Nuclear Information System (INIS)

    Navratil, J.D.

    1985-01-01

    Neutral bifunctional organophosphorus extractants, such as octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and dihexyl-N,N-diethylcarbamoylmethylphosphonate (CMP), are under study at the Rocky Flats Plant (RFP) to remove plutonium and americium from the 7M nitric acid waste. These compounds extract trivalent actinides from strong nitric acid, a property which distinguishes them from monofunctional organiphosphorus reagents. Furthermore, the reagents extract hydroytic plutonium (IV) polymer which is present in the acid waste stream. The compounds extract trivalent actinides with a 3:1 stoichiometry, whereas tetra- and hexavalent actinides extract with a stoichiometry of 2:1. Preliminary studies indicate that the extracted plutonium polymer complex contains one to two molecules of CMP per plutonium ion and the plutonium(IV) maintains a polymeric structure. Recent studies by Horwitz and co-workers conclude that the CMPO and CMP reagents behave as monodentate ligands. At RFP, three techniques are being tested for using CMP and CMPO to remove plutonium and americium from nitric acid waste streams. The different techniques are liquid-liquid extraction, extraction chromatography, and solid-supported liquid membranes. Recent tests of the last two techniques will be briefly described. In all the experiments, CMP was an 84% pure material from Bray Oil Co. and CMPO was 98% pure from M and T Chemicals

  12. Neurotoxicity in Preclinical Models of Occupational Exposure to Organophosphorus Compounds

    Science.gov (United States)

    Voorhees, Jaymie R.; Rohlman, Diane S.; Lein, Pamela J.; Pieper, Andrew A.

    2017-01-01

    Organophosphorus (OPs) compounds are widely used as insecticides, plasticizers, and fuel additives. These compounds potently inhibit acetylcholinesterase (AChE), the enzyme that inactivates acetylcholine at neuronal synapses, and acute exposure to high OP levels can cause cholinergic crisis in humans and animals. Evidence further suggests that repeated exposure to lower OP levels insufficient to cause cholinergic crisis, frequently encountered in the occupational setting, also pose serious risks to people. For example, multiple epidemiological studies have identified associations between occupational OP exposure and neurodegenerative disease, psychiatric illness, and sensorimotor deficits. Rigorous scientific investigation of the basic science mechanisms underlying these epidemiological findings requires valid preclinical models in which tightly-regulated exposure paradigms can be correlated with neurotoxicity. Here, we review the experimental models of occupational OP exposure currently used in the field. We found that animal studies simulating occupational OP exposures do indeed show evidence of neurotoxicity, and that utilization of these models is helping illuminate the mechanisms underlying OP-induced neurological sequelae. Still, further work is necessary to evaluate exposure levels, protection methods, and treatment strategies, which taken together could serve to modify guidelines for improving workplace conditions globally. PMID:28149268

  13. Preparation of Electrochemical Biosensor for Detection of Organophosphorus Pesticides

    Directory of Open Access Journals (Sweden)

    Ashish Gothwal

    2014-01-01

    Full Text Available Polyvinyl chloride (PVC can be used to develop reaction beaker which acts as electrochemical cell for the measurement of OP pesticides. Being chemically inert, corrosion resistant, and easy in molding to various shapes and size, PVC can be used for the immobilization of enzyme. Organophosphorus hydrolase was immobilized covalently onto the chemically activated inner surface of PVC beaker by using glutaraldehyde as a coupling agent. The carbon nanotubes paste working electrode was constructed for amperometric measurement at a potential of +0.8 V. The biosensor showed optimum response at pH 8.0 with incubation temperature of 40°C. Km and Imax for substrate (methyl parathion were 322.58 µM and 1.1 µA, respectively. Evaluation study showed a correlation of 0.985, which was in agreement with the standard method. The OPH biosensor lost 50% of its initial activity after its regular use for 25 times over a period of 50 days when stored in 0.1 M sodium phosphate buffer, pH 8.0 at 4°C. No interference was observed by interfering species.

  14. ANALYSIS OF ORGANOPHOSPHORUS POISONING, AT TERTIARY CARE HOSPITAL: A REPORT

    Directory of Open Access Journals (Sweden)

    Shakuntala

    2015-01-01

    Full Text Available BACKGROUND: Organophosphorus (OP compounds are the most common suicidal poison in developing countries and mortality continues to be high. The present study was aimed to know the pattern and outcome of the OP poisoning. METHODOLOGY: A record based retrospective study from January 2013 - December 2013 was Conducted in a tertiary care hospital and data regarding age, gender, domicile, type of poison, manner of poisoning, seasonal trends, marital status, motive behind poisoning , socio - economic status and outcome was collected in a pre - structured Performa. All data were documented, analyzed and interpreted as per the laid down protocol. RESULTS : out of total 1575 cases of OP compound poisoning, 71.73% (1130 were male, 28.27% (445 were female, 34.6% were in the age group 21 - 30 years, 70.95% were of low socio - economic status, Occupation wise agricultural workers were on top of the list (70.07%, The commonest (93.78% motive behind poisoning was suicidal in both males and females, Financial problem was one of the commonest (51.22% reasons of poisoning. The mortality rate in our study was 13.47%. CONCLUSION : Y oung and adult males of Low socio - economic class, rural, both literate and illiterate agriculturists commonly abuse this substance to commit suicide

  15. Differences between organophosphorus insecticides in human self-poisoning: a prospective cohort study.

    Science.gov (United States)

    Eddleston, Michael; Eyer, Peter; Worek, Franz; Mohamed, Fahim; Senarathna, Lalith; von Meyer, Ludwig; Juszczak, Edmund; Hittarage, Ariyasena; Azhar, Shifa; Dissanayake, Wasantha; Sheriff, M H Rezvi; Szinicz, Ladislaus; Dawson, Andrew H; Buckley, Nick A

    Although more than 100 organophosphorus insecticides exist, organophosphorus poisoning is usually regarded as a single entity, distinguished only by the compound's lethal dose in animals. We aimed to determine whether the three most common organophosphorus insecticides used for self-poisoning in Sri Lanka differ in the clinical features and severity of poisoning they cause. We prospectively studied 802 patients with chlorpyrifos, dimethoate, or fenthion self-poisoning admitted to three hospitals. Blood cholinesterase activity and insecticide concentration were measured to determine the compound and the patients' response to insecticide and therapy. We recorded clinical outcomes for each patient. Compared with chlorpyrifos (35 of 439, 8.0%), the proportion dying was significantly higher with dimethoate (61 of 264, 23.1%, odds ratio [OR] 3.5, 95% CI 2.2-5.4) or fenthion (16 of 99, 16.2%, OR 2.2, 1.2-4.2), as was the proportion requiring endotracheal intubation (66 of 439 for chlorpyrifos, 15.0%; 93 of 264 for dimethoate, 35.2%, OR 3.1, 2.1-4.4; 31 of 99 for fenthion, 31.3%, 2.6, 1.6-4.2). Dimethoate-poisoned patients died sooner than those ingesting other pesticides and often from hypotensive shock. Fenthion poisoning initially caused few symptoms but many patients subsequently required intubation. Acetylcholinesterase inhibited by fenthion or dimethoate responded poorly to pralidoxime treatment compared with chlorpyrifos-inhibited acetylcholinesterase. Organophosphorus insecticide poisoning is not a single entity, with substantial variability in clinical course, response to oximes, and outcome. Animal toxicity does not predict human toxicity since, although chlorpyrifos is generally the most toxic in rats, it is least toxic in people. Each organophosphorus insecticide should be considered as an individual poison and, consequently, patients might benefit from management protocols developed for particular organophosphorus insecticides.

  16. Positively-charged semi-tunnel is a structural and surface characteristic of polyphosphate-binding proteins: an in-silico study.

    Directory of Open Access Journals (Sweden)

    Zheng Zachory Wei

    Full Text Available Phosphate is essential for all major life processes, especially energy metabolism and signal transduction. A linear phosphate polymer, polyphosphate (polyP, linked by high-energy phosphoanhydride bonds, can interact with various proteins, playing important roles as an energy source and regulatory factor. However, polyP-binding structures are largely unknown. Here we proposed a putative polyP binding site, a positively-charged semi-tunnel (PCST, identified by surface electrostatics analyses in polyP kinases (PPKs and many other polyP-related proteins. We found that the PCSTs in varied proteins were folded in different secondary structure compositions. Molecular docking calculations revealed a significant value for binding affinity to polyP in PCST-containing proteins. Utilizing the PCST identified in the β subunit of PPK3, we predicted the potential polyP-binding domain of PPK3. The discovery of this feature facilitates future searches for polyP-binding proteins and discovery of the mechanisms for polyP-binding activities. This should greatly enhance the understanding of the many physiological functions of protein-bound polyP and the involvement of polyP and polyP-binding proteins in various human diseases.

  17. Basal electric and magnetic fields of celestial bodies come from positive-negative charge separation caused by gravitation of quasi-Casimir pressure in weak interaction

    Science.gov (United States)

    Chen, Shao-Guang

    According to f =d(mv)/dt=m(dv/dt)+ v(dm/dt), a same gravitational formula had been de-duced from the variance in physical mass of QFT and from the variance in mass of inductive energy-transfer of GR respectively: f QF T = f GR = -G (mM/r2 )((r/r)+(v/c)) when their interaction-constants are all taken the experimental values (H05-0029-08, E15-0039-08). f QF T is the quasi-Casimir pressure. f GR is equivalent to Einstein's equation, then more easy to solve it. The hypothesis of the equivalent principle is not used in f QF T , but required by f GR . The predictions of f QF T and f GR are identical except that f QF T has quantum effects but f GR has not and f GR has Lense-Thirring effect but f QF T has not. The quantum effects of gravitation had been verified by Nesvizhevsky et al with the ultracold neutrons falling in the earth's gravitational field in 2002. Yet Lense-Thirring effect had not been measured by GP-B. It shows that f QF T is essential but f GR is phenomenological. The macro-f QF T is the statistic average pressure collided by net virtual neutrinos ν 0 flux (after self-offset in opposite directions) and in direct proportion to the mass. But micro-f QF T is in direct proportion to the scattering section. The electric mass (in inverse proportion to de Broglie wavelength λ) far less than nucleonic mass and the electric scattering section (in direct proportion to λ2 ) far large than that of nucleon, then the net ν 0 flux pressure exerted to electron far large than that to nucleon and the electric displacement far large than that of nucleon, it causes the gravitational polarization of positive-negative charge center separation. Because the gravity far less than the electromagnetic binding force, in atoms the gravitational polarization only produces a little separation. But the net ν 0 flux can press a part freedom electrons in plasma of ionosphere into the earth's surface, the static electric force of redundant positive ions prevents electrons from further

  18. A 90-day study of sub-chronic oral toxicity of 20 nm positively charged zinc oxide nanoparticles in Sprague Dawley rats

    Directory of Open Access Journals (Sweden)

    Park HS

    2014-12-01

    Full Text Available Hark-Soo Park,1 Seon-Ju Kim,1 Taek-Jin Lee,1 Geon-Yong Kim,1 EunHo Meang,1 Jeong-Sup Hong,1 Su-Hyon Kim,1 Sang-Bum Koh,1 Seung-Guk Hong,1 Yle-Shik Sun,1 Jin Seok Kang,2 Yu-Ri Kim,3 Meyoung-Kon Kim,3 Jayoung Jeong,4 Jong-Kwon Lee,4 Woo-Chan Son,5 Jae-Hak Park61General Toxicology Team, Korea Testing and Research Institute, Seoul, 2Department of Biomedical Laboratory Science, Namseoul University, Cheonan, 3Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, 4National Institute of Food and Drug Safety Evaluation, Seoul, 5Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, 6Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, KoreaPurpose: The study reported here was conducted to determine the systemic oral toxicity and to find the no-observed-adverse-effect level of 20 nm positively charged zinc oxide (ZnOSM,20(+ nanoparticles in Sprague Dawley rats for 90 days.Methods: For the 90-day toxicity study, the high dose was set as 500 mg per kg of body weight (mg/kg and the middle and low dose were set to 250 mg/kg and 125 mg/kg, respectively. The rats were held for a 14-day recovery period after the last administration, to observe for the persistence or reduction of any toxic effects. A distributional study was also carried out for the systemic distribution of ZnOSM,20(+ NPs.Results: No rats died during the test period. There were no significant clinical changes due to the test article during the experimental period in functional assessment, body weight, food and water consumption, ophthalmological testing, urine analysis, necropsy findings, or organ weights, but salivation was observed immediately after administration in both sexes. The total red blood cell count was increased, and hematocrit, albumin, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration were decreased significantly compared with

  19. Organophosphorus flame retardants – Toxicity and influence on human health

    Directory of Open Access Journals (Sweden)

    Elżbieta Bruchajzer

    2015-06-01

    Full Text Available Organophosphorus flame retardants (flame retardants, FRs have been used for several decades in many industries, including the production of dyes, varnishes, adhesives, synthetic resins, polyvinyl chloride, hydraulic fluids, plastics and textiles. Their importance in recent times has increased due to i.a., significantly reduced use of polybrominated diphenyl ethers (PBDEs – persistent organic pollutants, dangerous for the environment. The aim of this study was to review the available literature data concerning phosphorous FRs primarily for neurotoxic, fertility, reproductive and carcinogenic effects. The analysis concerned the following most commonly used substances: tris(2-ethylhexylphosphate (TEHP, tris(2-butoxyethylphosphate (TBEP, triphenyl phosphate (TPP, tris(2-chloroethylphosphate (TCEP, tetrakis(hydroxymethyl-phosphonium chloride (THPC, tributyl phosphate (TBP, tricresyl phosphate (TCP, tris(2-chloroisopropylphosphate (TCPP, tris(1,3-dichloroisopropylphosphate (TDCP and tetrakis(hydroxymethyl phosphonium sulphate (THPS. In animal studies neurotoxic effects were found after exposure to TBEP, THPC, TBP and TCP, while in humans they were observed only after exposure to TCP. TCEP, THPS, TBP, TCP and TDCP caused disorders in fertility and/or fetal development of animals. Adverse effects on reproduction in humans may be caused by TPP, TCP, and TDCP. In laboratory animals the development of tumors was observed after high doses of TEHP, TCEP, TBP and TDCP. None of these compounds is classified as a human carcinogen. The environmental toxicity of phosphate FRs is low (except for TPP, TCEP and TBEP. They are not stable compounds, in living organisms they are metabolised and quickly excreted. Therefore, they can be used as an alternative to PBDEs. Med. Pr. 2015;66(2:235–264

  20. Degradation of organophosphorus compounds by X-ray irradiation

    International Nuclear Information System (INIS)

    Trebse, P.; Arcon, I.

    2002-01-01

    Complete text of publication follows. Our research presented in this contribution aims to elucidate the degradation mechanisms of organophosphate pesticides as organic pollutants by X-ray irradiation. Diazinon, one of the most widely used pesticides in Slovenia, has been chosen as a model compound for the study of radiation induced degradation of organophosphorus pesticides. Recent studies have shown that the degradation of the pesticide at normal conditions (room temperature, exposure to daylight) is strongly enhanced when the pesticide is exposed to UV light (Hg lamp, λ=254 nm, XeCl excimer laser, λ=308 nm). In our study we irradiated the pesticide in aqueous media with a white x-ray beam from a conventional x-ray source. Mo X-ray tube operating at the high voltage of 55 kV and a current of 45 mA was used. The flux of the continuous X-ray beam was stabilized within 1%. Saturated water solution of the pesticide (volume: 4mL, conc. of 40 mg L -1 ) was inserted in 1 cm long lucite cell with 1 mm thick lucite windows. The whole volume of the solution in the cell was exposed to the unfiltered X-ray beam. The dose rate on the sample was about 1 mGy/s. Different irradiation times between 30 min to 120 min were chosen to study the dependence of the pesticide decomposition with the absorbed dose. Solid phase extraction was employed for sample extraction from the solution, and gas chromatography was used for the identification and quantification of the compounds. The results show that the concentration of the pesticide in the solution decreases exponentially with the exposure time, i.e. with the absorbed dose. At irradiation conditions described above, the time constant of the exponential decrease was 74 min

  1. Cognitive decline, mortality, and organophosphorus exposure in aging Mexican Americans.

    Science.gov (United States)

    Paul, Kimberly C; Ling, Chenxiao; Lee, Anne; To, Tu My; Cockburn, Myles; Haan, Mary; Ritz, Beate

    2018-01-01

    Cognitive impairment is a major health concern among older Mexican Americans, associated with significant morbidity and mortality, and may be influenced by environmental exposures. To investigate whether agricultural based ambient organophosphorus (OP) exposure influences 1) the rate of cognitive decline and mortality and 2) whether these associations are mediated through metabolic or inflammatory biomarkers. In a subset of older Mexican Americans from the Sacramento Area Latino Study on Aging (n = 430), who completed modified mini-mental state exams (3MSE) up to 7 times (1998-2007), we examined the relationship between estimated ambient OP exposures and cognitive decline (linear repeated measures model) and time to dementia or being cognitively impaired but not demented (CIND) and time to mortality (cox proportional hazards model). We then explored metabolic and inflammatory biomarkers as potential mediators of these relationships (additive hazards mediation). OP exposures at residential addresses were estimated with a geographic information system (GIS) based exposure assessment tool. Participants with high OP exposure in the five years prior to baseline experienced faster cognitive decline (β = 0.038, p = 0.02) and higher mortality over follow-up (HR = 1.91, 95% CI = 1.12, 3.26). The direct effect of OP exposure was estimated at 241 (95% CI = 27-455) additional deaths per 100,000 person-years, and the proportion mediated through the metabolic hormone adiponectin was estimated to be 4% 1.5-19.2). No other biomarkers were associated with OP exposure. Our study provides support for the involvement of OP pesticides in cognitive decline and mortality among older Mexican Americans, possibly through biologic pathways involving adiponectin. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Positively charged residues at the five-fold symmetry axis of cell culture-adapted foot-and-mouth disease virus permit novel receptor interactions.

    Science.gov (United States)

    Berryman, Stephen; Clark, Stuart; Kakker, Naresh K; Silk, Rhiannon; Seago, Julian; Wadsworth, Jemma; Chamberlain, Kyle; Knowles, Nick J; Jackson, Terry

    2013-08-01

    Field isolates of foot-and-mouth disease virus (FMDV) have a restricted cell tropism which is limited by the need for certain RGD-dependent integrin receptors. In contrast, cell culture-adapted viruses use heparan sulfate (HS) or other unidentified molecules as receptors to initiate infection. Here, we report several novel findings resulting from cell culture adaptation of FMDV. In cell culture, a virus with the capsid of the A/Turkey/2/2006 field isolate gained the ability to infect CHO and HS-deficient CHO cells as a result of a single glutamine (Q)-to-lysine (K) substitution at VP1-110 (VP1-(Q)110(K)). Using site-directed mutagenesis, the introduction of lysine at this same site also resulted in an acquired ability to infect CHO cells by type O and Asia-1 FMDV. However, this ability appeared to require a second positively charged residue at VP1-109. CHO cells express two RGD-binding integrins (α5β1 and αvβ5) that, although not used by FMDV, have the potential to be used as receptors; however, viruses with the VP1-(Q)110(K) substitution did not use these integrins. In contrast, the VP1-(Q)110(K) substitution appeared to result in enhanced interactions with αvβ6, which allowed a virus with KGE in place of the normal RGD integrin-binding motif to use αvβ6 as a receptor. Thus, our results confirmed the existence of nonintegrin, non-HS receptors for FMDV on CHO cells and revealed a novel, non-RGD-dependent use of αvβ6 as a receptor. The introduction of lysine at VP1-110 may allow for cell culture adaptation of FMDV by design, which may prove useful for vaccine manufacture when cell culture adaptation proves intractable.

  3. A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

    Science.gov (United States)

    Curtis, Colin K; Marek, Antonin; Smirnov, Alex I

    2017-01-01

    This article reports a comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively (hydroxylated) or negatively (carboxylated) charged nanodiamonds (ND). Immersion in −ND suspensions resulted in a decrease in the macroscopic friction coefficients to values in the range 0.05–0.1 for both stainless steel and alumina, while +ND suspensions yielded an increase in friction for stainless steel contacts but little to no increase for alumina contacts. Quartz crystal microbalance (QCM), atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements were employed to assess nanoparticle uptake, surface polishing, and resistance to solid–liquid interfacial shear motion. The QCM studies revealed abrupt changes to the surfaces of both alumina and stainless steel upon injection of –ND into the surrounding water environment that are consistent with strong attachment of NDs and/or chemical changes to the surfaces. AFM images of the surfaces indicated slight increases in the surface roughness upon an exposure to both +ND and −ND suspensions. A suggested mechanism for these observations is that carboxylated −NDs from aqueous suspensions are forming robust lubricious deposits on stainless and alumina surfaces that enable gliding of the surfaces through the −ND suspensions with relatively low resistance to shear. In contrast, +ND suspensions are failing to improve tribological performance for either of the surfaces and may have abraded existing protective boundary layers in the case of stainless steel contacts. This study therefore reveals atomic scale details associated with systems that exhibit starkly different macroscale tribological properties, enabling future efforts to predict and design complex lubricant interfaces. PMID:29046852

  4. Positively Charged Residues at the Five-Fold Symmetry Axis of Cell Culture-Adapted Foot-and-Mouth Disease Virus Permit Novel Receptor Interactions

    Science.gov (United States)

    Berryman, Stephen; Clark, Stuart; Kakker, Naresh K.; Silk, Rhiannon; Seago, Julian; Wadsworth, Jemma; Chamberlain, Kyle; Knowles, Nick J.

    2013-01-01

    Field isolates of foot-and-mouth disease virus (FMDV) have a restricted cell tropism which is limited by the need for certain RGD-dependent integrin receptors. In contrast, cell culture-adapted viruses use heparan sulfate (HS) or other unidentified molecules as receptors to initiate infection. Here, we report several novel findings resulting from cell culture adaptation of FMDV. In cell culture, a virus with the capsid of the A/Turkey/2/2006 field isolate gained the ability to infect CHO and HS-deficient CHO cells as a result of a single glutamine (Q)-to-lysine (K) substitution at VP1-110 (VP1-Q110K). Using site-directed mutagenesis, the introduction of lysine at this same site also resulted in an acquired ability to infect CHO cells by type O and Asia-1 FMDV. However, this ability appeared to require a second positively charged residue at VP1-109. CHO cells express two RGD-binding integrins (α5β1 and αvβ5) that, although not used by FMDV, have the potential to be used as receptors; however, viruses with the VP1-Q110K substitution did not use these integrins. In contrast, the VP1-Q110K substitution appeared to result in enhanced interactions with αvβ6, which allowed a virus with KGE in place of the normal RGD integrin-binding motif to use αvβ6 as a receptor. Thus, our results confirmed the existence of nonintegrin, non-HS receptors for FMDV on CHO cells and revealed a novel, non-RGD-dependent use of αvβ6 as a receptor. The introduction of lysine at VP1-110 may allow for cell culture adaptation of FMDV by design, which may prove useful for vaccine manufacture when cell culture adaptation proves intractable. PMID:23740982

  5. A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

    Directory of Open Access Journals (Sweden)

    Colin K. Curtis

    2017-09-01

    Full Text Available This article reports a comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively (hydroxylated or negatively (carboxylated charged nanodiamonds (ND. Immersion in −ND suspensions resulted in a decrease in the macroscopic friction coefficients to values in the range 0.05–0.1 for both stainless steel and alumina, while +ND suspensions yielded an increase in friction for stainless steel contacts but little to no increase for alumina contacts. Quartz crystal microbalance (QCM, atomic force microscopy (AFM and scanning electron microscopy (SEM measurements were employed to assess nanoparticle uptake, surface polishing, and resistance to solid–liquid interfacial shear motion. The QCM studies revealed abrupt changes to the surfaces of both alumina and stainless steel upon injection of –ND into the surrounding water environment that are consistent with strong attachment of NDs and/or chemical changes to the surfaces. AFM images of the surfaces indicated slight increases in the surface roughness upon an exposure to both +ND and −ND suspensions. A suggested mechanism for these observations is that carboxylated −NDs from aqueous suspensions are forming robust lubricious deposits on stainless and alumina surfaces that enable gliding of the surfaces through the −ND suspensions with relatively low resistance to shear. In contrast, +ND suspensions are failing to improve tribological performance for either of the surfaces and may have abraded existing protective boundary layers in the case of stainless steel contacts. This study therefore reveals atomic scale details associated with systems that exhibit starkly different macroscale tribological properties, enabling future efforts to predict and design complex lubricant interfaces.

  6. Covariance of charged amino acids at positions 322 and 440 of HIV-1 Env contributes to coreceptor specificity of subtype B viruses, and can be used to improve the performance of V3 sequence-based coreceptor usage prediction algorithms.

    Directory of Open Access Journals (Sweden)

    Kieran Cashin

    Full Text Available The ability to determine coreceptor usage of patient-derived human immunodeficiency virus type 1 (HIV-1 strains is clinically important, particularly for the administration of the CCR5 antagonist maraviroc. The envelope glycoprotein (Env determinants of coreceptor specificity lie primarily within the gp120 V3 loop region, although other Env determinants have been shown to influence gp120-coreceptor interactions. Here, we determined whether conserved amino acid alterations outside the V3 loop that contribute to coreceptor usage exist, and whether these alterations improve the performance of V3 sequence-based coreceptor usage prediction algorithms. We demonstrate a significant covariant association between charged amino acids at position 322 in V3 and position 440 in the C4 Env region that contributes to the specificity of HIV-1 subtype B strains for CCR5 or CXCR4. Specifically, positively charged Lys/Arg at position 322 and negatively charged Asp/Glu at position 440 occurred more frequently in CXCR4-using viruses, whereas negatively charged Asp/Glu at position 322 and positively charged Arg at position 440 occurred more frequently in R5 strains. In the context of CD4-bound gp120, structural models suggest that covariation of amino acids at Env positions 322 and 440 has the potential to alter electrostatic interactions that are formed between gp120 and charged amino acids in the CCR5 N-terminus. We further demonstrate that inclusion of a "440 rule" can improve the sensitivity of several V3 sequence-based genotypic algorithms for predicting coreceptor usage of subtype B HIV-1 strains, without compromising specificity, and significantly improves the AUROC of the geno2pheno algorithm when set to its recommended false positive rate of 5.75%. Together, our results provide further mechanistic insights into the intra-molecular interactions within Env that contribute to coreceptor specificity of subtype B HIV-1 strains, and demonstrate that incorporation

  7. Blood cholinesterases as human biomarkers of organophosphorus pesticide exposure.

    Science.gov (United States)

    Nigg, H N; Knaak, J B

    2000-01-01

    The organophosphorus pesticides of this review were discovered in 1936 during the search for a replacement for nicotine for cockroach control. The basic biochemical characteristics of RBC AChE and BChE were determined in the 1940s. The mechanism of inhibition of both enzymes and other serine esterases was known in the 1940s and, in general, defined in the 1950s. In 1949, the death of a parathion mixer-loader dictated blood enzyme monitoring to prevent acute illness from organophosphorus pesticide intoxication. However, many of the chemical and biochemical steps for serine enzyme inhibition by OP compounds remain unknown today. The possible mechanisms of this inhibition are presented kinetically beginning with simple (by comparison) Michaelis-Menten substrate enzyme interaction kinetics. As complicated as the inhibition kinetics appear here, PBPK model kinetics will be more complex. The determination of inter- and intraindividual variation in RBC ChE and BChE was recognized early as critical knowledge for a blood esterase monitoring program. Because of the relatively constant production of RBCs, variation in RBC AChE was determined by about 1970. The source of plasma (or serum) BChE was shown to be the liver in the 1960s with the change in BChE phenotype to the donor in liver transplant patients. BChE activity was more variable than RBC AChE, and only in the 1990s have BChE individual variation questions been answered. We have reviewed the chemistry, metabolism, and toxicity of organophosphorus insecticides along with their inhibitory action toward tissue acetyl- and butyrylcholinesterases. On the basis of the review, a monitoring program for individuals mixing-loading and applying OP pesticides for commercial applicators was recommended. Approximately 41 OPs are currently registered for use by USEPA in the United States. Under agricultural working conditions, OPs primarily are absorbed through the skin. Liver P-450 isozymes catalyze the desulfurization of

  8. Dietary cumulative acute risk assessment of organophosphorus, carbamates and pyrethroids insecticides for the Brazilian population.

    NARCIS (Netherlands)

    Jardim, Andreia Nunes Oliveira; Brito, Alessandra Page; van Donkersgoed, Gerda; Boon, Polly E; Caldas, Eloisa Dutra

    Cumulative acute dietary risk assessments of organophosphorus (OPs), carbamates (CBs) and pyrethroids (PYs) were conducted for the Brazilian population. Residue data for 30786 samples of 30 foods were obtained from two national monitoring programs and one University laboratory, and consumption data

  9. Immobilization of Organophosphorus Acid Anhydrolase Mutant Y212F on Silica Nanospheres

    Science.gov (United States)

    2016-09-01

    wild type organophosphorus acid anhydrolase (OPAA) for activity on G-type chemical nerve agents and observed increased activity on the most- toxic ...eventual use in determining particle-binding efficiency and enzymatic activity ..................................................4 5. Fluoride assay...7 TABLES 1. Results of Fluoride Release Assay from DFP Testing of Y212F Enzyme, before and after Conjugation to

  10. Infrared Spectroscopic Observations on the Fate of Organophosphorus Compounds Exposed to Atmospheric Moisture. Part 3

    Science.gov (United States)

    2007-05-01

    FATE OF ORGANOPHOSPHORUS COMPOUNDS EXPOSED TO ATMOSPHERIC MOISTURE PART III. PHOSPHINES, PHOSPHITES , PHOSPHONITES, PHOSPHINITES, PHOSPHORIC ACIDS ...The investigation continues with Phosphines, Phosphites , Phosphonites, Phosphinites, Phosphoric Acids , Phosphonic Acids , Phosphinic Acids , Phosphine...infrared spectrum of di-(2-ethylhexyl) phosphoric acid as a liquid film between KBr windows is given in Figure 104. The band assignments are as follows

  11. Monoclonal antibody-based broad-specificity immunoassay for monitoring organophosphorus pesticides in environmental water samples

    Science.gov (United States)

    The extensive use of organophosphorus pesticides (OPs) in agriculture and domestic settings can result in widespread water contamination. The development of easy-to-use and rapid-screening immunoassay methods in a class-selective manner is a topic of considerable environmental interest. In this wo...

  12. Determination of organophosphorus acids by thermo-spray liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Wils, E.R.J.; Hulst, A.G.

    1988-01-01

    The determination of thirteen organophosphorus acids, hydrolysis products of nerve agents and pesticides, by a combination of ion-pair liquid chromatography on a reversed-phase C18 column and thermospray mass spectrometry was investigated. Ammonium acetate and three tetraalkylammonium salts with

  13. RESEARCH OF HEAVY METALS, ORGANOCHLORINE AND ORGANOPHOSPHORUS PESTICIDES IN POWDERED INFANT FORMULA

    Directory of Open Access Journals (Sweden)

    M.C. Abete

    2009-02-01

    Full Text Available During the period between october 2007 and november 2008 were collected 60 samples of powdered infant formula. The analysis for the detection of heavy metals, organochlorine and organophosphorus pesticides show that the environmental situation is under control and powdered infant formula satisfies this health requisite.

  14. Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web

    NARCIS (Netherlands)

    Brandsma, S.H.; Leonards, P.E.G.; Leslie, H.A.; de Boer, J.

    2015-01-01

    Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of

  15. Colorimetric and dynamic light scattering detection of DNA sequences by using positively charged gold nanospheres: a comparative study with gold nanorods

    Science.gov (United States)

    Pylaev, T. E.; Khanadeev, V. A.; Khlebtsov, B. N.; Dykman, L. A.; Bogatyrev, V. A.; Khlebtsov, N. G.

    2011-07-01

    We introduce a new genosensing approach employing CTAB (cetyltrimethylammonium bromide)-coated positively charged colloidal gold nanoparticles (GNPs) to detect target DNA sequences by using absorption spectroscopy and dynamic light scattering. The approach is compared with a previously reported method employing unmodified CTAB-coated gold nanorods (GNRs). Both approaches are based on the observation that whereas the addition of probe and target ssDNA to CTAB-coated particles results in particle aggregation, no aggregation is observed after addition of probe and nontarget DNA sequences. Our goal was to compare the feasibility and sensitivity of both methods. A 21-mer ssDNA from the human immunodeficiency virus type 1 HIV-1 U5 long terminal repeat (LTR) sequence and a 23-mer ssDNA from the Bacillus anthracis cryptic protein and protective antigen precursor (pagA) genes were used as ssDNA models. In the case of GNRs, unexpectedly, the colorimetric test failed with perfect cigar-like particles but could be performed with dumbbell and dog-bone rods. By contrast, our approach with cationic CTAB-coated GNPs is easy to implement and possesses excellent feasibility with retention of comparable sensitivity—a 0.1 nM concentration of target cDNA can be detected with the naked eye and 10 pM by dynamic light scattering (DLS) measurements. The specificity of our method is illustrated by successful DLS detection of one-three base mismatches in cDNA sequences for both DNA models. These results suggest that the cationic GNPs and DLS can be used for genosensing under optimal DNA hybridization conditions without any chemical modifications of the particle surface with ssDNA molecules and signal amplification. Finally, we discuss a more than two-three-order difference in the reported estimations of the detection sensitivity of colorimetric methods (0.1 to 10-100 pM) to show that the existing aggregation models are inconsistent with the detection limits of about 0.1-1 pM DNA and that

  16. [On necessity to modify biochemical methods for detecting organophosphorus componds in chemical weapons extinction objects (review of literature)].

    Science.gov (United States)

    Prokofieva, D S; Shmurak, V I; Sadovnikov, S V; Gontcharov, N V

    2015-01-01

    The article covers problems of biochemical methods assessing organophosphorus toxic compounds in objects of chemical weapons extinction. The authors present results of works developing new, more specific and selective biochemical methods.

  17. Comparison of the Developmental and Acute Neurotoxicity of a Library of Organophosphorus Pesticides Using a Vertebrate Behavioral Assay

    Science.gov (United States)

    The U.S. Environmental Protection Agency is evaluating methods to screen and prioritize organophosphorus pesticides for neurotoxicity using behavioral tests in an in vivo, vertebrate, medium-throughput model (zebrafish; Danio rerio). Our behavioral testing paradigm assesses the e...

  18. Measuring momentum for charged particle tomography

    Science.gov (United States)

    Morris, Christopher; Fraser, Andrew Mcleod; Schultz, Larry Joe; Borozdin, Konstantin N.; Klimenko, Alexei Vasilievich; Sossong, Michael James; Blanpied, Gary

    2010-11-23

    Methods, apparatus and systems for detecting charged particles and obtaining tomography of a volume by measuring charged particles including measuring the momentum of a charged particle passing through a charged particle detector. Sets of position sensitive detectors measure scattering of the charged particle. The position sensitive detectors having sufficient mass to cause the charged particle passing through the position sensitive detectors to scatter in the position sensitive detectors. A controller can be adapted and arranged to receive scattering measurements of the charged particle from the charged particle detector, determine at least one trajectory of the charged particle from the measured scattering; and determine at least one momentum measurement of the charged particle from the at least one trajectory. The charged particle can be a cosmic ray-produced charged particle, such as a cosmic ray-produced muon. The position sensitive detectors can be drift cells, such as gas-filled drift tubes.

  19. Positive photocatalysis of a Diels-Alder reaction by quenching of excited naphthalene-indole charge-transfer complex with cyclohexadiene.

    Science.gov (United States)

    Gonzalez-Béjar, María; Stiriba, Salah-Eddine; Miranda, Miguel A; Pérez-Prieto, Julia

    2007-02-01

    [reaction: see text] Naphthalene photo-catalyzes formation of cyclohexadiene-indole cycloadducts in a wavelength-dependent process. Steady-state irradiation and time-resolved fluorescence studies agree well with NP-InH ground-state charge transfer (CT) complexes as the key species responsible for the photo-catalyzed process.

  20. Adhesion, growth and osteogenic differentiation of human bone marrow mesenchymal stem cells on positively and negatively charged and uncharged ferroelectric crystal surfaces\

    Czech Academy of Sciences Publication Activity Database

    Vandrovcová, Marta; Bačáková, Lucie; Vaněk, Přemysl; Petzelt, Jan

    2016-01-01

    Roč. 19, č. 135 (2016), s. 2-7 ISSN 1429-7248 R&D Projects: GA ČR(CZ) GA15-01558S Institutional support: RVO:67985823 ; RVO:68378271 Keywords : electroactive ceramics * surface charge * cell number * bone matrix mineralization Subject RIV: EI - Biotechnology ; Bionics; BO - Biophysics (FZU-D)

  1. Deciphering the "chemical" nature of the exotic isotopes of hydrogen by the MC-QTAIM analysis: the positively charged muon and the muonic helium as new members of the periodic table.

    Science.gov (United States)

    Goli, Mohammad; Shahbazian, Shant

    2014-04-14

    This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic helium, i.e., the negatively charged muon plus helium nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions. Accordingly, the "atoms in molecules" analysis performed on various asymmetric exotic isotopomers of the hydrogen molecule, recently detected experimentally [Science, 2011, 331, 448], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atoms. Various derived properties of atomic basins containing the muonic helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization. However, with some tolerance, they may also be categorized as hydrogen basins though with a smaller electronegativity. All in all, the present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, which are difficult to elucidate by experimental and/or alternative theoretical schemes.

  2. Charge imbalance

    International Nuclear Information System (INIS)

    Clarke, J.

    1981-01-01

    This article provides a long theoretical development of the main ideas of charge imbalance in superconductors. Concepts of charge imbalance and quasiparticle charge are introduced, especially in regards to the use of tunnel injection in producing and detecting charge imbalance. Various mechanisms of charge relaxation are discussed, including inelastic scattering processes, elastic scattering in the presence of energy-gap anisotropy, and various pair-breaking mechanisms. In each case, present theories are reviewed in comparison with experimental data

  3. Comparative study on cleanup procedures for the determination of organophosphorus pesticides in vegetables

    International Nuclear Information System (INIS)

    Alvin, Chai Lian Kuet; Lau, Seng

    2008-01-01

    A study was carried out to compare the cleanup procedures for the determination of organophosphorus pesticides in vegetables. Eleven organophosphorus pesticides were extracted with acetone and methylene chloride. Extracts were cleanup by solid-phase extraction (SPE) mixed-mode column using quaternary amine and aminopropyl (SAX/ NH 2 ) or octadecyl (C 18 ) sorbents. The pesticides were determined by gas chromatography with flame photometric detector. The recovery results obtained from the SPE SAX/ NH 2 and C 18 cleanups in carrot, cucumber and green mustard samples were in the range of 71.0 % to 115 %. Lower recoveries were obtained for polar pesticides, methamidophos and dimethoate. These results were compared to the method currently used in the laboratory which does not include any cleanup. (author)

  4. Calcium uptake by sarcoplasmic reticulum in the presence of organophosphorus insecticide methyl-parathion

    International Nuclear Information System (INIS)

    Blasiak, J.

    1995-01-01

    Using an isotope labelling technique it has been shown that an organophosphorus insecticide methyl parathion (0,0-diethyl 0-4-nitrophenyl phosphorothionate) depressed calcium uptake by sarcoplasmic reticulum isolated from rabbit hind leg muscle. The effect was significant for insecticide concentrations of 50 and 100 μM and was dose-dependent. The insecticide exerted a more pronounced effect on calcium uptake in the presence of ATP in the reticulum environment than in the absence of ATP. The inhibitory action of methyl parathion on Ca 2+ accumulation by sarcoplasmic reticulum can cause a rise in myoplasmic free Ca 2+ , the essential prerequisite for contracture activation. Because methyl parathion, as well as other organophosphorus insecticides, is primarily neurotoxic, evidence of non-specific effect could be important for assessing its environmental safety. (author). 20 refs, 2 figs

  5. Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)–pyridine-2,6-dicarboxylic acid probe

    International Nuclear Information System (INIS)

    Azab, Hassan A.; Duerkop, Axel; Anwar, Z.M.; Hussein, Belal H.M.; Rizk, Moustafa A.; Amin, Tarek

    2013-01-01

    Highlights: ► Europium (III) luminescence quenching has been used for sensing organophosphorous pesticides. ► Four guest pesticides chlorfenvinphos, malathion, azinphos, and paraxon ethyl were used. ► A sensitive rapid, cheap direct method for the determination of the pesticides has been developed. ► The method was applied to the determination of the OPs in tap, river, mineral, and waste waters. - Abstract: Luminescence quenching of a novel long lived Eu(III)–pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol–water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)–(PDCA) 2 probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)–pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0–35.0 μM. The detection limits were 0.24–0.55 μM for P3, P4, and P1 and 2.5 μM for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)–(PDCA) 2 were evaluated. Positive and negative values of entropy (ΔS) and enthalpy (ΔH) changes for Eu(III)–(PDCA) 2 –P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation.

  6. Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)-pyridine-2,6-dicarboxylic acid probe

    Energy Technology Data Exchange (ETDEWEB)

    Azab, Hassan A., E-mail: azab2@yahoo.com [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Duerkop, Axel [Institute of Analytical Chemistry, Chemo and Biosensors, Regensburg University, D-93040 Regensburg (Germany); Anwar, Z.M.; Hussein, Belal H.M.; Rizk, Moustafa A.; Amin, Tarek [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

    2013-01-08

    Highlights: Black-Right-Pointing-Pointer Europium (III) luminescence quenching has been used for sensing organophosphorous pesticides. Black-Right-Pointing-Pointer Four guest pesticides chlorfenvinphos, malathion, azinphos, and paraxon ethyl were used. Black-Right-Pointing-Pointer A sensitive rapid, cheap direct method for the determination of the pesticides has been developed. Black-Right-Pointing-Pointer The method was applied to the determination of the OPs in tap, river, mineral, and waste waters. - Abstract: Luminescence quenching of a novel long lived Eu(III)-pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol-water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)-(PDCA){sub 2} probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)-pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0-35.0 {mu}M. The detection limits were 0.24-0.55 {mu}M for P3, P4, and P1 and 2.5 {mu}M for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)-(PDCA){sub 2} were evaluated. Positive and negative values of entropy ({Delta}S) and enthalpy ({Delta}H) changes for Eu(III)-(PDCA){sub 2}-P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation.

  7. Organophosphorus insecticides: Toxic effects and bioanalytical tests for evaluating toxicity during degradation processes

    Directory of Open Access Journals (Sweden)

    Čolović Mirjana B.

    2013-01-01

    Full Text Available Organophosphorus insecticides have been the most applied group of insecticides for the last two decades. Their main toxic effects are related to irreversible inactivation of acetylcholinesterase (AChE. Actually, they covalently bind to serine OH group in the enzyme active site forming phosphorylated enzyme that cannot hydrolyze acetylcholine. Organophosphorus insecticides in the environment undergo the natural degradation pathway including mainly homogeneous and heterogeneous hydrolysis (especially at high pH generating non-inhibiting products. Additionally, thio organophosphates are easily oxidized by naturally present oxidants and UV light, forming more toxic and stable oxons. Thus, oxidative degradation procedures, generally referred as advanced oxidation processes (AOP, have been applied for their efficient removal from contaminated waters. The most applied bioassays to monitor the organophosphate toxicity i.e. the detoxification degree during AOP are Vibrio fischeri and AChE bioassays. Vibrio fischeri toxicity test exploits bioluminescence as the measure of luciferase activity of this marine bacterium, whereas AChE bioassay is based on AChE activity inhibition. Both bioanalytical techniques are rapid (several minutes, simple, sensitive and reproducible. Vibrio fischeri test seems to be a versatile indicator of toxic compounds generated in AOP for organophosphorus insecticides degradation. However, detection of neurotoxic AChE inhibitors, which can be formed in AOP of some organophosphates, requires AChE bioassays. Therefore, AChE toxicity test is more appropriate for monitoring the degradation processes of thio organophosphates, because more toxic oxo organophosphates might be formed and overlooked by Vibrio fischeri bioluminescence inhibition. In addition, during organophosphates removal by AOP, compounds with strong genotoxic potential may be formed, which cannot be detected by standard toxicity tests. For this reason, determination of

  8. Organophosphorus acid anhydrolase from Alteromonas macleodii: structural study and functional relationship to prolidases

    Czech Academy of Sciences Publication Activity Database

    Štěpánková, Andrea; Dušková, Jarmila; Skálová, Tereza; Hašek, Jindřich; Koval, Tomáš; Ostergaard, L. H.; Dohnálek, Jan

    2013-01-01

    Roč. 69, č. 4 (2013), s. 346-354 ISSN 1744-3091 R&D Projects: GA ČR GA310/09/1407; GA ČR GA305/07/1073; GA MŠk EE2.3.30.0029 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : organophosphorus acid anhydrolase * prolidases * bifunctional Subject RIV: CE - Biochemistry Impact factor: 0.568, year: 2013

  9. A Common Mechanism for Resistance to Oxime Reactivation of Acetylcholinesterase Inhibited by Organophosphorus Compounds

    Science.gov (United States)

    2013-01-01

    reactivated than AChE conjugates inhibited by the corresponding Rp enantiomers and this effect is enhanced as the size of the O-alkyl substituents of OP...Organophosphates and Carbamates, Butterworth & Heinemann , Oxford, 1992. pp. 555–577. [2] P. Taylor, Anticholinesterase agents, in: L.L. Brunton, J.S...application of the Hammett equation with the constants rph in the chemistry of organophosphorus compounds, Russ. Chem. Rev. 38 (1969) 795–811. [13

  10. Long Alkyl Chain Organophosphorus Coupling Agents for in Situ Surface Functionalization by Reactive Milling

    Directory of Open Access Journals (Sweden)

    Annika Betke

    2014-08-01

    Full Text Available Innovative synthetic approaches should be simple and environmentally friendly. Here, we present the surface modification of inorganic submicrometer particles with long alkyl chain organophosphorus coupling agents without the need of a solvent, which makes the technique environmentally friendly. In addition, it is of great benefit to realize two goals in one step: size reduction and, simultaneously, surface functionalization. A top-down approach for the synthesis of metal oxide particles with in situ surface functionalization is used to modify titania with long alkyl chain organophosphorus coupling agents. A high energy planetary ball mill was used to perform reactive milling using titania as inorganic pigment and long alkyl chain organophosphorus coupling agents like dodecyl and octadecyl phosphonic acid. The final products were characterized by IR, NMR and X-ray fluorescence spectroscopy, thermal and elemental analysis as well as by X-ray powder diffraction and scanning electron microscopy. The process entailed a tribochemical phase transformation from the starting material anatase to a high-pressure modification of titania and the thermodynamically more stable rutile depending on the process parameters. Furthermore, the particles show sizes between 100 nm and 300 nm and a degree of surface coverage up to 0.8 mmol phosphonate per gram.

  11. Fractional charges

    International Nuclear Information System (INIS)

    Saminadayar, L.

    2001-01-01

    20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)

  12. A STUDY OF PREDICTING THE NEED FOR VENTILATOR SUPPORT AND OUTCOME IN ORGANOPHOSPHORUS POISONING

    Directory of Open Access Journals (Sweden)

    Kalinga Bommankatte Eranaik

    2017-04-01

    Full Text Available BACKGROUND Organophosphorus compound poisoning is the most common poisonings in India because of easy availability, often requiring ICU care and ventilator support. Clinical research has indicated that respiratory failure is the most important cause of death due to Organophosphorus poisoning. It results in respiratory muscle weakness, pulmonary oedema, respiratory depression, increased secretions and bronchospasm. These complications and death can be prevented with timely Institution of ventilator support. The aim of present study was to identify the factors and predicting the need for ventilator support and outcome. Aim of the Study- To predict the need for ventilator support and outcome in organophosphate poisoning. MATERIALS AND METHODS Seventy consecutive patients admitted with a history of organophosphorus poisoning at KIMS, Hubli were taken for study after considering the inclusion and exclusion criteria. Detailed history, confirmation of poisoning, examination and other than routine investigations serum pseudocholinesterase and arterial blood gas analysis was done. The severity of organophosphorus poisoning was graded as mild, moderate and severe based on the factors which influence the need for ventilator support. RESULTS This study was conducted in 70 patients, out of which 48 (68.6% were male patients and 22 (31.4% were female patients. Among them 37 (53% patients required ventilation and 33 (47% expired. Chlorpyrifos, Dichlorvos and Monocrotophos were most commonly consumed poisons. 74% patients who consumed these compounds required ventilator support and 73% patients expired. 100% of patients presented with pin point pupil, fasciculation score > 4, respiratory rate > 20, GCS score < 7 and severe grade of poisoning required ventilator support and pseudocholinesterase < 900 U/L, 70% of metabolic acidosis and atropine requirement more than 180 mg within 48 hours required ventilator support and associated with high mortality. CONCLUSION

  13. First charge collection and position-precision data on the medium-resistivity silicon strip detectors before and after neutron irradiation up to 2x1014 n/cm2

    International Nuclear Information System (INIS)

    Li Zheng; Dezillie, B.; Eremin, V.; Li, C.J.; Verbitskaya, E.

    1999-01-01

    Test strip detectors of 125 μm, 500 μm, and 1 mm pitches with about 1 cm 2 areas have been made on medium-resistivity silicon wafers (1.3 and 2.7 kΩ cm). Detectors of 500 μm pitch have been tested for charge collection and position precision before and after neutron irradiation (up to 2x10 14 n/cm 2 ) using 820 and 1030 nm laser lights with different beam-spot sizes. It has been found that for a bias of 250 V a strip detector made of 1.3 kΩ cm (300 μm thick) can be fully depleted before and after an irradiation of 2x10 14 n/cm 2 . For a 500 μm pitch strip detector made of 2.7 kΩ cm tested with an 1030 nm laser light with 200 μm spot size, the position reconstruction error is about 14 μm before irradiation, and 17 μm after about 1.7x10 13 n/cm 2 irradiation. We demonstrated in this work that medium resistivity silicon strip detectors can work just as well as the traditional high-resistivity ones, but with higher radiation tolerance. We also tested charge sharing and position reconstruction using a 1030 nm wavelength (300 μm absorption length in Si at RT) laser, which provides a simulation of MIP particles in high-physics experiments in terms of charge collection and position reconstruction

  14. Internal Charging

    Science.gov (United States)

    Minow, Joseph I.

    2014-01-01

    (1) High energy (>100keV) electrons penetrate spacecraft walls and accumulate in dielectrics or isolated conductors; (2) Threat environment is energetic electrons with sufficient flux to charge circuit boards, cable insulation, and ungrounded metal faster than charge can dissipate; (3) Accumulating charge density generates electric fields in excess of material breakdown strenght resulting in electrostatic discharge; and (4) System impact is material damage, discharge currents inside of spacecraft Faraday cage on or near critical circuitry, and RF noise.

  15. Charge gradient microscopy

    Science.gov (United States)

    Roelofs, Andreas; Hong, Seungbum

    2018-02-06

    A method for rapid imaging of a material specimen includes positioning a tip to contact the material specimen, and applying a force to a surface of the material specimen via the tip. In addition, the method includes moving the tip across the surface of the material specimen while removing electrical charge therefrom, generating a signal produced by contact between the tip and the surface, and detecting, based on the data, the removed electrical charge induced through the tip during movement of the tip across the surface. The method further includes measuring the detected electrical charge.

  16. Charge preamplifier

    International Nuclear Information System (INIS)

    Chaminade, R.; Passerieux, J.P.

    1961-01-01

    We describe a charge preamplifier having the following properties: - large open loop gain giving both stable gain and large input charge transfer; - stable input grid current with aging and without any adjustment; - fairly fast rise; - nearly optimum noise performance; - industrial material. (authors)

  17. Charge Meter

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 4. Charge Meter: Easy Way to Measure Charge and Capacitance: Some Interesting Electrostatic Experiments. M K Raghavendra V Venkataraman. Classroom Volume 19 Issue 4 April 2014 pp 376-390 ...

  18. Charging machine

    International Nuclear Information System (INIS)

    Medlin, J.B.

    1976-01-01

    A charging machine for loading fuel slugs into the process tubes of a nuclear reactor includes a tubular housing connected to the process tube, a charging trough connected to the other end of the tubular housing, a device for loading the charging trough with a group of fuel slugs, means for equalizing the coolant pressure in the charging trough with the pressure in the process tubes, means for pushing the group of fuel slugs into the process tube and a latch and a seal engaging the last object in the group of fuel slugs to prevent the fuel slugs from being ejected from the process tube when the pusher is removed and to prevent pressure liquid from entering the charging machine. 3 claims, 11 drawing figures

  19. Determination of Twenty Organophosphorus Pesticides in Wheat Samples from Different Regions of Iran

    Directory of Open Access Journals (Sweden)

    Attaollah Shakoori *

    2017-09-01

    Full Text Available Background: Organophosphorus pesticides are widely used in agriculture, homes, gardens, and veterinary practices. Extensive application of pesticides in agriculture often results in residues of these compounds being absorbed into the foods, including wheat. The aim of this study was to evaluate the residue levels of 20 organophosphorus pesticides in wheat samples collected from different regions of Iran. Methods: This research reports a rapid, specific and sensitive multiresidue method based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS sample preparation method and gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–SIM–MS to evaluate 20 organophosphorus pesticides in wheat samples. Results: In the concentration range of 20-200 ng/g, the calibration curves for each analyte was linear with a determination coefficient (R2 of 0.993 to 0.999. The limits of detection (LODs and quantitation (LOQs were between 2.5-6.7 and 7.5-20 ng/g, respectively. The mean recoveries obtained for three fortification levels (25, 50 and 100 ng/g, five replicates each were 80-114% with a satisfactory precision (RSD<20%. 31.1% samples contained residues of one or more target compounds. Chlorpyrifos was the most common residue (17.8%, followed by pirimiphos-methyl (6.7%, diazinon (4.4%, chlorpyrifos-methyl (1.1% and malathion (1.1%. Conclusion: Among the detected pesticides, only diazinon and malathion are permitted pesticides for wheat production in Iran. However, their concentrations were below the maximum residue levels (MRLs established by the Iranian National Standard Organization (INSO.

  20. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    Science.gov (United States)

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  1. Pralidoxime in acute organophosphorus insecticide poisoning--a randomised controlled trial.

    Directory of Open Access Journals (Sweden)

    Michael Eddleston

    2009-06-01

    Full Text Available Poisoning with organophosphorus (OP insecticides is a major global public health problem, causing an estimated 200,000 deaths each year. Although the World Health Organization recommends use of pralidoxime, this antidote's effectiveness remains unclear. We aimed to determine whether the addition of pralidoxime chloride to atropine and supportive care offers benefit.We performed a double-blind randomised placebo-controlled trial of pralidoxime chloride (2 g loading dose over 20 min, followed by a constant infusion of 0.5 g/h for up to 7 d versus saline in patients with organophosphorus insecticide self-poisoning. Mortality was the primary outcome; secondary outcomes included intubation, duration of intubation, and time to death. We measured baseline markers of exposure and pharmacodynamic markers of response to aid interpretation of clinical outcomes. Two hundred thirty-five patients were randomised to receive pralidoxime (121 or saline placebo (114. Pralidoxime produced substantial and moderate red cell acetylcholinesterase reactivation in patients poisoned by diethyl and dimethyl compounds, respectively. Mortality was nonsignificantly higher in patients receiving pralidoxime: 30/121 (24.8% receiving pralidoxime died, compared with 18/114 (15.8% receiving placebo (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 0.88-3.26, p = 0.12. Incorporating the baseline amount of acetylcholinesterase already aged and plasma OP concentration into the analysis increased the HR for patients receiving pralidoxime compared to placebo, further decreasing the likelihood that pralidoxime is beneficial. The need for intubation was similar in both groups (pralidoxime 26/121 [21.5%], placebo 24/114 [21.1%], adjusted HR 1.27 [95% CI 0.71-2.29]. To reduce confounding due to ingestion of different insecticides, we further analysed patients with confirmed chlorpyrifos or dimethoate poisoning alone, finding no evidence of benefit.Despite clear reactivation of

  2. Charge independence and charge symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G A [Washington Univ., Seattle, WA (United States). Dept. of Physics; van Oers, W T.H. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada)

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs.

  3. Charge independence and charge symmetry

    International Nuclear Information System (INIS)

    Miller, G.A.

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs

  4. Rapid charging of nickel-cadmium accumulators

    Energy Technology Data Exchange (ETDEWEB)

    Bruck, F

    1972-01-01

    Four types of charging of gas-tight Ni-Cd accumulators (a) normal; (b) accelerated; (c) rapid; and (d) ultra-rapid are described. For rapid charging, a built-in temperature sensor cuts off charging current at a prescribed point. In ultra-rapid charging, 50% charge can be attained in 3.5 min. and 25% charge within 50 sec. In the second phase of ultra-rapid charging, a surplus of oxygen is released at the positive electrode and a safety valve is provided for pressure reduction. Characteristic curves are given for various rates of charging and some data on discharge rates is also given.

  5. Synthesis of positively charged hybrid PHMB-stabilized silver nanoparticles: the search for a new type of active substances used in plant protection products

    Science.gov (United States)

    Krutyakov, Yurii A.; Kudrinsky, Alexey A.; Gusev, Alexander A.; Zakharova, Olga V.; Klimov, Alexey I.; Yapryntsev, Alexey D.; Zherebin, Pavel M.; Shapoval, Olga A.; Lisichkin, Georgii V.

    2017-07-01

    Modern agriculture calls for a decrease in pesticide application, particularly in order to decrease the negative impact on the environment. Therefore the development of new active substances and plant protection products (PPP) to minimize the chemical load on ecosystems is a very important problem. Substances based on silver nanoparticles are a promising solution of this problem because of the fact that in correct doses such products significantly increase yields and decrease crop diseases while displaying low toxicity to humans and animals. In this paper we for the first time propose application of polymeric guanidine compounds with varying chain lengths (from 10 to 130 elementary links) for the design and synthesis of modified silver nanoparticles to be used as the basis of a new generation of PPP. Colloidal solutions of nanocrystalline silver containing 0.5 g l-1 of silver and 0.01-0.4 g l-1 of polyhexamethylene biguanide hydrochloride (PHMB) were obtained by reduction of silver nitrate with sodium borohydride in the presence of PHMB. The field experiment has shown that silver-containing solutions have a positive effect on agronomic properties of potato, wheat and apple. Also the increase in activity of such antioxidant system enzymes as peroxidase and catalase in the tissues of plants treated with nanosilver has been registered.

  6. Organophosphorus pesticide and ester analysis by using comprehensive two-dimensional gas chromatography with flame photometric detection.

    Science.gov (United States)

    Liu, Xiangping; Li, Dengkun; Li, Jiequan; Rose, Gavin; Marriott, Philip J

    2013-12-15

    Thirty-seven phosphorus (P)-containing compounds comprising organophosphorus pesticides and organophosphate esters were analyzed by using comprehensive two-dimensional gas chromatography with flame photometric detection in P mode (GC × GC-FPD(P)), with a non-polar/moderately polar column set. A suitable modulation temperature and period was chosen based on experimental observation. A number of co-eluting peak pairs on the (1)D column were well separated in 2D space. Excellent FPD(P) detection selectivity, responding to compounds containing the P atom, produces clear 2D GC × GC plots with little interference from complex hydrocarbon matrices. Limits of detection (LOD) were within the range of 0.0021-0.048 μmol L(-1), and linear calibration correlation coefficients (R(2)) for all 37 P-compounds were at least 0.998. The P-compounds were spiked in 2% diesel and good reproducibility for their response areas and retention times was obtained. Spiked recoveries were 88%-157% for 5 μg L(-1) and 80%-138% for 10 μg L(-1) spiked levels. Both (1)tR and (2)tR shifts were noted when the content of diesel was in excess of 5% in the matrix. Soil samples were analyzed by using the developed method; some P-compounds were positively detected. In general, this study shows that GC × GC-FPD(P) is an accurate, sensitive and simple method for P-compound analysis in complicated environmental samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Construction of genetically engineered bacteria that degrades organophosphorus pesticide residues and can be easily detected by the fluorescence.

    Science.gov (United States)

    Li, Qin; Wang, Pan; Chen, Rui; Li, Wei; Wu, Yi-Jun

    2014-01-01

    Organophosphorus compounds (OPs) are widely used in agriculture and industry and there is increased concern about their toxicological effects in the environment. Bioremediation can offer an efficient and cost-effective option for the removal of OPs. Herein, we describe the construction of a genetically engineered microorganism (GEM) that can degrade OPs and be directly detected and monitored in the environment using an enhanced green fluorescent protein (EGFP) fusion strategy. The coding regions of EGFP, a reporter protein that can fluoresce by itself, and organophosphorus hydrolase (OPH), which has a broad substrate specificity and is able to hydrolyse a number of organophosphorus pesticides, were cloned into the expression vector pET-28b. The fusion protein of EGFP-OPH was expressed in E. coli BL21 (DE3) and the protein expression reached the highest level at 11 h after isopropyl beta-D-thiogalactopyranoside induction. The fluorescence of the GEM was detected by fluorescence spectrophotometry and microscopy, and its ability to degrade OPs was determined by OPH activity assay. Those GEM that express the fusion protein (EGFP and OPH) exhibited strong fluorescence intensity and also potent hydrolase activity, which could be used to degrade organophosphorus pesticide residues in the environment and can also be directly monitored by fluorescence.

  8. AMPEROMETRIC THICK-FILM STRIP ELECTRODES FOR MONITORING ORGANOPHOSPHATE NERVE AGENTS BASED ON IMMOBILIZED ORGANOPHOSPHORUS HYDROLASE. (R823663)

    Science.gov (United States)

    An amperometric biosensor based on the immobilization of organophosphorus hydrolase(OPH) onto screen-printed carbon electrodes is shown useful for the rapid, sensitive, and low-costdetection of organophosphate (OP) nerve agents. The sensor relies upon the sensitive and ra...

  9. DEVELOPMENT OF A RISK ASSESSMENT MODEL FOR THE EFFECTS OF ORGANOPHOSPHORUS PESTICIDES ON INFECTIOUS DISEASE SUSCEPTIBILITY AND THE IMMUNE SYSTEM

    Science.gov (United States)

    There is increased concern about the sublethal effects of organophosphorus (OP) pesticides on human and animal health. This class of chemicals has been shown to affect the immune function of macrophages and lymphocytes. Malathion, an OP compound, is one of the most widely used ...

  10. Structural Analysis and Bioengineering of Thermostable Pyrococcus furiosus Prolidase for the Optimization of Organophosphorus Nerve Agent Detoxification

    Science.gov (United States)

    2012-04-26

    organophosphorus acid anhydrase from a halophilic bacterial isolate. J Bacteriol, 173, 1938-1943. Du, X., Tove, S., Kast -Hutcheson, K. & Grunden, A. M...1938-1943. Du, X., Tove, S., Kast -Hutcheson, K. & Grunden, A. M. 2005. Characterization of the dinuclear metal center of Pyrococcus furiosus

  11. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang, E-mail: ceszf@mail.sysu.edu.cn; Ouyang, Gangfeng, E-mail: cesoygf@mail.sysu.edu.cn

    2016-04-15

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  12. Metagenomic Functional Potential Predicts Degradation Rates of a Model Organophosphorus Xenobiotic in Pesticide Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Thomas C. Jeffries

    2018-02-01

    Full Text Available Chemical contamination of natural and agricultural habitats is an increasing global problem and a major threat to sustainability and human health. Organophosphorus (OP compounds are one major class of contaminant and can undergo microbial degradation, however, no studies have applied system-wide ecogenomic tools to investigate OP degradation or use metagenomics to understand the underlying mechanisms of biodegradation in situ and predict degradation potential. Thus, there is a lack of knowledge regarding the functional genes and genomic potential underpinning degradation and community responses to contamination. Here we address this knowledge gap by performing shotgun sequencing of community DNA from agricultural soils with a history of pesticide usage and profiling shifts in functional genes and microbial taxa abundance. Our results showed two distinct groups of soils defined by differing functional and taxonomic profiles. Degradation assays suggested that these groups corresponded to the organophosphorus degradation potential of soils, with the fastest degrading community being defined by increases in transport and nutrient cycling pathways and enzymes potentially involved in phosphorus metabolism. This was against a backdrop of taxonomic community shifts potentially related to contamination adaptation and reflecting the legacy of exposure. Overall our results highlight the value of using holistic system-wide metagenomic approaches as a tool to predict microbial degradation in the context of the ecology of contaminated habitats.

  13. Separating esterase targets of organophosphorus compounds in the brain by preparative chromatography.

    Science.gov (United States)

    Mangas, I; Vilanova, E; Benabent, M; Estévez, J

    2014-02-10

    Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox and phenylmethyl sulfonylfluoride as inhibitors and phenyl valerate as a substrate. Three different enzymatic components were discriminated and called Eα, Eβ and Eγ. In this work, a fractionation procedure with various steps was developed using protein native separation methods by preparative HPLC. Gel permeation chromatography followed by ion exchange chromatography allowed enriched fractions with different kinetic behaviors. The soluble chicken brain fraction was fractionated, while total esterase activity, proteins and enzymatic components Eα, Eβ and Eγ were monitored in each subfraction. After the analysis, 13 fractions were pooled and conserved. Preincubation of the soluble chicken brain fraction of with the organophosphorus mipafox gave rise to a major change in the ion exchange chromatography profile, but not in the molecular exchanged chromatography profile, which suggest that mipafox permanently modifies the ionic properties of numerous proteins. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Organophosphorus and Organochlorine Pesticides Bioaccumulation by Eichhornia crassipes in Irrigation Canals in an Urban Agricultural System.

    Science.gov (United States)

    Mercado-Borrayo, B M; Cram Heydrich, Silke; Pérez, Irma Rosas; Hernández Quiroz, Manuel; De León Hill, Claudia Ponce

    2015-01-01

    A natural wetland in Mexico City Metropolitan Area is one of the main suppliers of crops and flowers, and in consequence its canals hold a high concentration of organochlorine (OC) and organophosphorus (OP) pesticides. There is also an extensive population of water hyacinth (Eichhornia crassipes), which is considered a plague; but literature suggests water hyacinth may be used as a phytoremediator. This study demonstrates bioaccumulation difference for the OC in vivo suggesting their bioaccumulation is ruled by their log K(ow), while all the OP showed bioaccumulation regardless of their log K(ow). The higher bioaccumulation factors (BAF) of the accumulated OC pesticides cannot be explained by their log K(ow), suggesting that the OC pesticides may also be transported passively into the plant. Translocation ratios showed that water hyacinth is an accumulating plant with phytoremediation potential for all organophosphorus pesticides studied and some organochlorine pesticides. An equation for free water surface wetlands with floating macrophytes, commonly used for the construction of water-cleaning wetlands, showed removal of the pesticides by the wetland with room for improvement with appropriate management.

  15. The analysis of common metabolites of organophosphorus pesticides in urine by gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Park, Seong Soo; Pyo, Hee Soo; Lee, Kang Jin; Park, Song Ja; Park, Taek Kyu

    1998-01-01

    Most organophosphorus pesticides may be metabolized to yield some common phosphates in human or in animals, and these metabolites may be used as the exposure biomarkers to pesticides. In this study, we developed the extraction method of four phosphate metabolites from the spiked human urine in high recovery by the solid phase extraction with a reverse-phase cartridge (cyclohexyl silica) followed by the elution with methanol. The extracted urinary metabolites were derivatized with hexamethyldisilazane/trimethyl-chlorosilane/pyridine (2:1:10, v/v/v) and identified by gas chromatography/mass spectrometry. Calibration curve obtained from each metabolite standard using by GC/MS/SIM has shown good linearity and detection limits of metabolites were the range of 0.05-0.1 μg/ml in urine. Phenthoate, one of the organophosphorus pesticides, was orally administrated to rats. Four metabolites were detected in the rat urine. The results of this study may be applied to development of exposure biomarkers for monitoring of environmental pollutants

  16. Organochlorine and organophosphorus pesticide residues in fodder and milk samples along Musi river belt, India

    Directory of Open Access Journals (Sweden)

    Korrapati Kotinagu

    2015-04-01

    Full Text Available Aim: The present study was conducted to find the organochlorine pesticide (OCP and organophosphorus pesticide (OPP residues in fodder and milk samples along Musi river belt, India. Materials and Methods: Fodder and milk samples collected from the six zones of Musi river belt, Hyderabad India were analyzed by gas chromatography with electron capture detector for OCP residues and pulsated flame photometric detector for the presence of OPP residues. Results: The gas chromatographic analysis of fodder samples of Zone 5 of Musi river showed the residues of dicofol at concentration of 0.07±0.0007 (0.071-0.077. Among organophosphorus compounds, dimetheoate was present in milk samples collected from Zone 6 at a level of 0.13±0.006 (0.111-0.167. The residues of OCPs, OPPs and cyclodies were below the detection limit in the remaining fodder and milk samples collected from Musi river belt in the present study. Conclusion: The results indicate that the pesticide residues in fodder and milk samples were well below the maximum residue level (MRL values, whereas dicofol in fodder and dimethoate in milk were slightly above the MRL values specified by EU and CODEX.

  17. Organochlorine and organophosphorus pesticide residues in fodder and milk samples along Musi river belt, India.

    Science.gov (United States)

    Kotinagu, Korrapati; Krishnaiah, Nelapati

    2015-04-01

    The present study was conducted to find the organochlorine pesticide (OCP) and organophosphorus pesticide (OPP) residues in fodder and milk samples along Musi river belt, India. Fodder and milk samples collected from the six zones of Musi river belt, Hyderabad India were analyzed by gas chromatography with electron capture detector for OCP residues and pulsated flame photometric detector for the presence of OPP residues. The gas chromatographic analysis of fodder samples of Zone 5 of Musi river showed the residues of dicofol at concentration of 0.07±0.0007 (0.071-0.077). Among organophosphorus compounds, dimetheoate was present in milk samples collected from Zone 6 at a level of 0.13±0.006 (0.111-0.167). The residues of OCPs, OPPs and cyclodies were below the detection limit in the remaining fodder and milk samples collected from Musi river belt in the present study. The results indicate that the pesticide residues in fodder and milk samples were well below the maximum residue level (MRL) values, whereas dicofol in fodder and dimethoate in milk were slightly above the MRL values specified by EU and CODEX.

  18. Intensification of Organophosphorus Hydrolase Synthesis by Using Substances with Gas-Transport Function

    Directory of Open Access Journals (Sweden)

    Olga Senko

    2017-12-01

    Full Text Available We have performed studies and comparative analysis of the biosynthesis characteristics of intracellular recombinant enzyme, such as hexahistidine-containing organophosphorus hydrolase (His6-OPH in Escherichia coli SG13009[pREP4] cells when various perfluorocarbon compounds (PFC were introduced into the medium for cell cultivation. The PFC were found to facilitate the biosynthesis of His6-OPH: increased levels of the total OPH-activity (up to 37% were measured upon introduction of 1,1,1,2,2,3,3,4,4,5,5,6,6,6-tetradecafluorohexane (PFH and 4,7,10,13,16,19,22,25,28,31-decaoxaperfluoro-5,8,11,14,17,18,21,24,27,30-decamethyl tetratriacontane (Polyether II into culture medium. We have demonstrated the possibility of effective and multiple (at least five-fold use of PFH for biosynthesis of intracellular recombinant protein His6-OPH, which catalyzes the hydrolysis of organophosphorus pesticides (OP, is widely used in agriculture and can be applied as new antidote for OP-detoxification in vivo. The multiple use of PFH was achieved through recycling of this substance: sediment of Escherichia coli SG13009[pREP4] cell biomass was collected at the end of each culture growing step and disintegrated with ultrasound, and obtained residue containing almost all of the initially introduced PFC was then added to the medium at the start of the following culture growing step.

  19. ACUTE EXOGENOUS INTOXICATIONS WITH ORGANOPHOSPHORUS PESTICIDES: DURATION OF THE HOSPITAL TREATMENT AND CLINICAL CRITERIA FOR PROGNOSIS

    Directory of Open Access Journals (Sweden)

    Petko Marinov

    2017-05-01

    Full Text Available Purpose: Several criteria have been suggested to estimate the intoxication severity, yet so far no system of clinical criteria has been developed to determine the duration of hospitalisation. The forecast is linked to the influence of the extended corrected QT interval and GCS (Glasgow Coma Scale on the frequency of the developing acute pulmonary insufficiency and lethality. The average duration of hospital treatment is also crucial. First of all, it is determined by the intoxication severity and lasts from 3 to 26 days. The aim of this study is to develop an individual forecast about the duration of hospitalisation for patients suffering from acute exogenous intoxication with organophosphorus pesticides (OPP. Materials/Methods: The subjects are 160 patients. We use statistical regression analysis to study the significance of 5 of the most typical clinical indicators of organophosphorus intoxication on the duration of hospitalisation: type of conscience, presence of spasms, pulmonary oedema, shock and multi-organ insufficiency syndrome (MOIS. To forecast the treatment length, we obtain simplified mathematical expressions in the form of score estimates. Results: The significance of the clinical indicators “MOIS”, “conscience” and “spasm” has been confirmed. A forecast matrix that gives the opportunity to forecast the personal duration of hospital treatment for each patient has been built.

  20. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    International Nuclear Information System (INIS)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang; Ouyang, Gangfeng

    2016-01-01

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  1. Radiolytic investigations of solutions of organophosphorus compounds in cyclohexane and benzene

    International Nuclear Information System (INIS)

    Otrebski, W.

    1981-01-01

    Organphosphorus compounds are used in various branches of the chemical industry, but in many cases the reaction mechanisms are not well elucidated and less is known about the intermediates of organophosphines. In order to learn more about these rather complicated processes several organophosphorus compounds were used as model substrates in cyclohexane or benzene solution. The systems have been investigated applying the pulse radiolysis technique and steady-state irradiation methods. As representative solutes were chosen diphenylphosphinous chloride, diphenylmethylphosphine, and triphenylphosphine. By means of the pulse radiolysis it was possible to obtain spectroscopic and kinetic data for characterization of the various transients. The final radiolytic products have been analyzed following steady-state and multipulse radiolysis. Since some of the rate constants were not directly accessible by the applied kinetic method, they have been determined by simulation computation. Thereby the experimental data obtained by pulse radiolysis were used. Based on the kinetic, spectroscopic and computed data as well as on the identification of final products, it was possible to elucidate the reaction mechanism of the diphenylphosphinous chloride/cyclohexane system. As a main primary specie was identified the diphenylphoshorus radical. Its spectral and kinetic data have been determined. The reactions of diphenylmethylphosphine involve the same radical, but only to a lesser extent. The reactions of the primary radiolysis products with triphenylphosphine yield mainly adducts. The results represent a contribution in the field of reaction kinetics of organophosphorus compounds. (author)

  2. Adjacent effect on positive charge transfer from radical cation of n-dodecane to scavenger studied by supbicosecond pulse radiolysis, statistical and Monte Carlo approach

    International Nuclear Information System (INIS)

    Saeki, A.; Tagawa, S.; Kozawa, T.; Yoshida, Y.

    2003-01-01

    Time-dependent behaviors of radical cation in n-dodecane in the presence of high-concentrated cation scavenger triethylamine were measured by subpicosecond pulse radiolysis system. The significant reduction of the initial yield in the optical density was observed. This reduction were not able to be explained by the first order rate constant. Therefore, we assumed that this phenomena occur due to the adjacent effect of the solute molecules. We approached this effect by the statistical model and configurational-bias Monte Carlo method. In both methods, we supposed a condition that the cation site in the radical cation is delocalized and will be scavenged rapidly within the time resolution if the solute molecules is adjacent to any sites of the solvent. In addition to the adjacent effect, the fact that a large part of the solvent molecules is excluded by the solute molecules especially at high concentration was taken into consideration. First, we formulated this effect by a statistical model. In addition to the above assumption, this model is based on the following assumption; the effects of molecule's shape, conformation and interaction among molecules were ignored and the aggregation of the solute molecules were treated randomly. As a result, the formula indicated good agreement with the experimental data. Second, as another approach, we adopted the configurational-bias Monte Carlo simulation to reproduce the liquid system. The OLPS model was used to describe the intermolecular and intramolecular potentials. The adjacent effect estimated by this method corresponded to the experimental data with a threshold of 0.5 nm. This value are close to a typical reaction radius. The average number of adjacent solvent molecules and the distribution of aggregated solute's number were also collected from the position data

  3. New porphyrins bearing positively charged peripheral groups linked by a sulfonamide group to meso-tetraphenylporphyrin: interactions with calf thymus DNA.

    Science.gov (United States)

    Manono, Janet; Marzilli, Patricia A; Marzilli, Luigi G

    2009-07-06

    New water-soluble cationic meso-tetraarylporphyrins (TArP, Ar = 4-C(6)H(4)) and some metal derivatives have been synthesized and characterized. One main goal was to assess if N-methylpyridinium (N-Mepy) groups must be directly attached to the porphyrin core for intercalative binding of porphyrins to DNA. The new porphyrins have the general formula, [T(R(2)R(1)NSO(2)Ar)P]X(4/8) (R(1) = CH(3) or H and R(2) = N-Mepy-n-CH(2) with n = 2, 3, or 4; or R(1) = R(2) = Et(3)NCH(2)CH(2)). Interactions of selected porphyrins and metalloporphyrins (Cu(II), Zn(II)) with calf thymus DNA were investigated by visible circular dichroism (CD), absorption, and fluorescence spectroscopies. The DNA-induced changes in the porphyrin Soret region (a positive induced CD feature and, at high DNA concentration, increases in the Soret band and fluorescence intensities) indicate that the new porphyrins interact with DNA in an outside, non-self-stacking binding mode. Several new metalloporphyrins did not increase DNA solution viscosity and thus do not intercalate, confirming the conclusion drawn from spectroscopic studies. Porphyrins known to intercalate typically bear two or more N-Mepy groups directly attached to the porphyrin ring, such as the prototypical meso-tetra(N-Mepy)porphyrin tetracation (TMpyP(4)). The distances between the nitrogens of the N-Mepy group are estimated to be approximately 11 A (cis) and 16 A (trans) for the relatively rigid TMpyP(4). For the new flexible porphyrin, [T(N-Mepy-4-CH(2)(CH(3))NSO(2)Ar)P]Cl(4), the distances between the nitrogens are estimated to be able to span the range from approximately 9 to approximately 25 A. Thus, the N-Mepy groups in the new porphyrins can adopt the same spacing as in known intercalators such as TMpyP(4). The absence of intercalation by the new porphyrins indicates that the propensity for the N-Mepy group to facilitate DNA intercalation of cationic porphyrins requires direct attachment of N-Mepy groups to the porphyrin core.

  4. Third International Meeting on Esterases Reacting with Organophosphorus Compounds

    Science.gov (United States)

    1998-01-01

    cassette for negative selection, 884 bp of ACHE including exon 1, 1.6 kb of a Neor gene cassette for positive selection, 5.2 kb of the ACHE Bam HI...fragment including exon 6, and 3 kb of Bluescript. Deletion of exons 2-5 removed 80% of the ACHE coding sequence. The gene targeting vector was...expression due to environmental influences on CYP3A4 and the presence or absence of CYP3A5 which may be under genetic control in man. Plasma

  5. Hereditary folate malabsorption: A positively charged amino acid at position 113 of the proton-coupled folate transporter (PCFT/SLC46A1) is required for folic acid binding

    International Nuclear Information System (INIS)

    Lasry, Inbal; Berman, Bluma; Glaser, Fabian; Jansen, Gerrit; Assaraf, Yehuda G.

    2009-01-01

    The proton-coupled folate transporter (PCFT/SLC46A1) mediates intestinal folate uptake at acidic pH. Some loss of folic acid (FA) transport mutations in PCFT from hereditary folate malabsorption (HFM) patients cluster in R113, thereby suggesting a functional role for this residue. Herein, unlike non-conservative substitutions, an R113H mutant displayed 80-fold increase in the FA transport Km while retaining parental Vmax, hence indicating a major fall in folate substrate affinity. Furthermore, consistent with the preservation of 9% of parental transport activity, R113H transfectants displayed a substantial decrease in the FA growth requirement relative to mock transfectants. Homology modeling based on the crystal structures of the Escherichia coli transporter homologues EmrD and glycerol-3-phosphate transporter revealed that the R113H rotamer properly protrudes into the cytoplasmic face of the minor cleft normally occupied by R113. These findings constitute the first demonstration that a basic amino acid at position 113 is required for folate substrate binding.

  6. Resonance charge exchange processes

    International Nuclear Information System (INIS)

    Duman, E.L.; Evseev, A.V.; Eletskij, A.V.; Radtsig, A.A.; Smirnov, B.M.

    1979-01-01

    The calculation results for the resonance charge exchange cross sections for positive and negative atomic and molecular ions are given. The calculations are performed on the basis of the asymptotic theory. The factors affecting the calculation accuracy are analysed. The calculation data for 28 systems are compared with the experiment

  7. Recent Developments in Organophosphorus Flame Retardants Containing P-C Bond and Their Applications

    Directory of Open Access Journals (Sweden)

    Sophie Wendels

    2017-07-01

    Full Text Available Organophosphorus compounds containing P-C bonds are increasingly developed as flame retardant additives due to their excellent thermal and hydrolytic stability and ease of synthesis. The latest development (since 2010 in organophosphorus flame retardants containing P-C bonds summarized in this review. In this review, we have broadly classified such phosphorus compounds based on the carbon unit linked to the phosphorus atom i.e., could be a part of either an aliphatic or an aromatic unit. We have only considered those published literature where a P-C bond was created as a part of synthetic strategy to make either an intermediate or a final organophosphorus compound with an aim to use it as a flame retardant. General synthetic strategies to create P-C bonds are briefly discussed. Most popular synthetic strategies used for developing P-C containing phosphorus based flame retardants include Michael addition, Michaelis–Arbuzov, Friedels–Crafts and Grignard reactions. In general, most flame retardant derivatives discussed in this review have been prepared via a one- to two-step synthetic strategy with relatively high yields greater than 80%. Specific examples of P-C containing flame retardants synthesized via suitable synthetic strategy and their applications on various polymer systems are described in detail. Aliphatic phosphorus compounds being liquids or low melting solids are generally applied in polymers via coatings (cellulose or are incorporated in the bulk of the polymers (epoxy, polyurethanes during their polymerization as reactive or non-reactive additives. Substituents on the P atoms and the chemistry of the polymer matrix greatly influence the flame retardant behavior of these compounds (condensed phase vs. the gas phase. Recently, aromatic DOPO based phosphinate flame retardants have been developed with relatively higher thermal stabilities (>250 °C. Such compounds have potential as flame retardants for high temperature processable

  8. Sources for charged particles

    International Nuclear Information System (INIS)

    Arianer, J.

    1997-01-01

    This document is a basic course on charged particle sources for post-graduate students and thematic schools on large facilities and accelerator physics. A simple but precise description of the creation and the emission of charged particles is presented. This course relies on every year upgraded reference documents. Following relevant topics are considered: electronic emission processes, technological and practical considerations on electron guns, positron sources, production of neutral atoms, ionization, plasma and discharge, different types of positive and negative ion sources, polarized particle sources, materials for the construction of ion sources, low energy beam production and transport. (N.T.)

  9. Associating Oligonucleotides with Positively Charged Liposomes

    Czech Academy of Sciences Publication Activity Database

    Jurkiewicz, P.; Okruszek, A.; Hof, Martin; Langner, M.

    2003-01-01

    Roč. 8, č. 1 (2003), s. 77-84 ISSN 1425-8153 R&D Projects: GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4040901 Keywords : oligonucleotides * fluorescence correlation spectroscopy * DOTAP Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.455, year: 2003

  10. First charge collection and position-precision data on the medium-resistivity silicon strip detectors before and after neutron irradiation up to 2x10 sup 1 sup 4 n/cm sup 2

    CERN Document Server

    Li Zheng; Eremin, V; Li, C J; Verbitskaya, E

    1999-01-01

    Test strip detectors of 125 mu m, 500 mu m, and 1 mm pitches with about 1 cm sup 2 areas have been made on medium-resistivity silicon wafers (1.3 and 2.7 k OMEGA cm). Detectors of 500 mu m pitch have been tested for charge collection and position precision before and after neutron irradiation (up to 2x10 sup 1 sup 4 n/cm sup 2) using 820 and 1030 nm laser lights with different beam-spot sizes. It has been found that for a bias of 250 V a strip detector made of 1.3 k OMEGA cm (300 mu m thick) can be fully depleted before and after an irradiation of 2x10 sup 1 sup 4 n/cm sup 2. For a 500 mu m pitch strip detector made of 2.7 k OMEGA cm tested with an 1030 nm laser light with 200 mu m spot size, the position reconstruction error is about 14 mu m before irradiation, and 17 mu m after about 1.7x10 sup 1 sup 3 n/cm sup 2 irradiation. We demonstrated in this work that medium resistivity silicon strip detectors can work just as well as the traditional high-resistivity ones, but with higher radiation tolerance. We als...

  11. Estimation of solubility of organo-phosphorus extractants by P determination using molybdovanadophosphoric acid method

    International Nuclear Information System (INIS)

    Gill, J.S.; Kotekar, M.K.; Singh, H.

    2005-01-01

    Solvent extraction processes have been found to be suitable for uranium recovery from phosphoric acid. Various extractants like di-2-ethyl hexylphosphoric acid (D2EHPA), di-nonylphenyl phosphoric acid (DNPPA) and synergistic agents like tri-butyl phosphate (TBP), tri-octyl phosphine oxide (TOPO) have been used in liquid-liquid extraction of uranium from phosphoric acid. Contents of these organo-phosphorus compounds in aqueous raffinates need estimation for process requirements. Solubility of Tri-butyl phosphate (TBP) and Di-2-ethylhexyl phosphoric acid (D2EHPA) extractants have been determined in different media of water, oxalic acid (0.6M) and sulphuric acid (3.75M) solutions. These compounds were estimated by determining their phosphorus (P) contents employing molybdovanadophosphoric acid method, after digesting and solubalizing them in nitric and perchloric acid. (author)

  12. Concentration of Organochlorine and Organophosphorus Pesticides in Different Molluscs from Tighra Reservoir, Gwalior, India.

    Science.gov (United States)

    Mamta; Rao, R J; Wani, Khursheed Ahmad

    2015-09-01

    Concentration of organochlorine and organophosphorus pesticides and their metabolites were determined in whole body homogenate of L. acuminata, I. exustus, V. dissimilis, V. bengalensis, from Tighra Reservoir during summer and post monsoon season using GC-MS technique. The different types of pesticides viz., HCB, heptachlor, aldrin, endosulfan, dieldrin, p,p-DDT, choloropyrifos, methyl parathion, dicholorovos, ethion, malathion, parathion were found in resident molluscs studied. Concentration of these pesticides varied independently during the summer and the post monsoon season at monitored sites. The study concluded that presence of pesticides in Tighra Reservoir is a major concern on public and ecosystem health and use of biopesticides in the adjacent area of Reservoir is highly recommended.

  13. Electrochemical process for the treatment of water contaminated with organophosphorus pesticides

    International Nuclear Information System (INIS)

    Samet, Youssef; Agengui, Lamia; Abdelhedi, Ridha

    2009-01-01

    The aim of this work is the use of electrochemical process for the total mineralization of water contaminated with organophosphorus pesticides like chloropyrifos. This pesticide is widely used both for agricultural pest control and in households as a termiticide. The process was studied under galvanostatic polarization mode using Ta/PbO 2 anodes and graphite carbon bar as cathode. The kinetic of organic matter decay and the mineralization efficiency were evaluated by means of the chemical oxygen demand (COD) measurement. The influence of the experimental parameters such as the initial concentration of chloropyrifos, temperature, and current density, on the electrochemical process performance was investigated. The experimental results showed that COD removal always follows a pseudo-first-order kinetics. The degradation rate increased drastically with increasing current density and temperature. However, it decreased with the increase of the initial pollutant concentrations. Very high organic matter degradation, approximately 90 pour cent in 10 h experiments, was obtained.

  14. Degradation kinetics of seven organophosphorus pesticides in milk during yoghurt processing

    Directory of Open Access Journals (Sweden)

    LI-YING BO

    2011-03-01

    Full Text Available Bovine milk spiked with seven organophosphorus pesticides, i.e., dimethoate, fenthion, malathion, methyl parathion, monocrotophos, phorate and trichlorphon, was fermented at 42 °C with commercial directed vat set (DVS starters to investigate the degradation kinetics of the pesticides during yoghurt processing. The spiked pesticides were extracted from the prepared samples with an organic solvent and analyzed by gas chromatography after purification. Based on published results that the degradation kinetics of pesticides is first order, the rate constant of degradation and the half live period of the pesticides were calculated. The results indicated that degradation of the pesticides in milk during yoghurt processing were enhanced by one or both starters, except for malathion, and the two commercial DVS starters had different influences on the degradation kinetics of the pesticides.

  15. Assessment of some biochemical and hematological parameters in treated with the organophosphorus insecticide cyanox

    International Nuclear Information System (INIS)

    ElMahdy, A.A.; Fayz, V.; Hassanin, M.M.

    2002-01-01

    The effect of single acute oral doses of 29 and 58 mg/kg of cyanox (an organophosphorus pesticide) on selected biochemical and hematological parameters in male rats were investigated. This compound inhibited blood acetylcholine esterase (AChE) significantly, over 72 hours post-treatment with the higher dose level. Serum alkaline phosphatase (ALP) was significantly depressed, 48 hr after treatment with 58 mg/kg. Serum bilirubin was elevated significantly after 48 and 24 hr of treatment with 29 and 58 mg/kg, respectively. Serum cholesterol increased significantly over 48 hr post-treatment with both dose levels.Hypertriglyceridemia was noticed only in the higher dose group. Serum total lipids were increased significantly at both dose levels. A slight treatment-related effect was observed in serum creatinine level. The hematological investigations revealed the occurrence of macrocytic normochromic anemia that was more evident in the lower dose group

  16. Is the stoichiometry of the europium nitrate complexes with neutral organophosphorus extractants be anticipated?

    International Nuclear Information System (INIS)

    Beudaert, Ph.; Lamare, V.; Wipff, G.

    2001-01-01

    Molecular dynamics simulations have been performed in water on europium nitrate complexes with three neutral organophosphorus extractants (TBP, TPPO and CMPO) in order to determine on what criteria it is possible to obtain by simulations the experimental 1:3 stoichiometry in organic solution. This stoichiometry was investigated by progressive saturation of the cation coordination sphere. When the nitrate counter-ions are bidentate, the 1:3 stoichiometry corresponds to the degree of saturation where the interaction energy between europium and water becomes repulsive. Beyond this stoichiometry, complexes with TPPO and CMPO are unstable, although a 1:4 complex with TBP may exist but its formation appears to be energetically unfavored. (author)

  17. Influence of modifiers on the separation of dysprosium from neodymium using organophosphorus acid derivates

    Energy Technology Data Exchange (ETDEWEB)

    Elwert, Tobias; Schwarz, Sabrina; Goldmann, Daniel [TU Clausthal, Clausthal-Zellerfeld (Germany). Lehrstuhl fuer Rohstoffaufbereitung und Recycling

    2016-01-15

    The aim of this study was to investigate the applicability of three organophosphorus acid derivates (D2EHPA, EHEHPA and Cyanex 572) for the separation of terbium and dysprosium from praseodymium and neodymium from NdFeB magnets in chloride solution. A special focus was put on the effect of phase modifiers. The investigations revealed that all extractants show in general a similar extraction behavior but the extraction is shifted to higher pH values in the order D2EHPA < EHEHPA < Cyanex 572. Therefore, and due to higher realizable loadings, EHEHPA and Cyanex 572 are more suitable for the investigated separation problem than D2EHPA. Whereas EHEHPA requires 1-decanol as phase modifier, Cyanex 572 can be employed without modifier addition.

  18. Nicotine And The Risk Of Exposure To The Organophosphorus Insecticide Cyolane

    International Nuclear Information System (INIS)

    Hassanin M, M.; Bahig Mervat, E.

    1999-01-01

    The present investigation was undertaken to show the effect of repeated oral doses of nicotine (0.5 mg/kg) on rats pretreated or during treatment with cyolane (0.5 mg/kg 1/20 LD 5 0). The results revealed that exposure of smokers to organophosphorus pesticides exerted slight changes in GOT and GPT. Alkaline phosphatase was significantly increased to reach maximal (228.54 and 148.64%) after nicotine + cyolane and/or nicotine were given for a week to rats pretreated with cyolane for 2 weeks. Total protein, albumin and Albumin/Globulin (A/G) ratio were also affected. Administration of nicotine along with cyolane to rats showed a significant increase in cholesterol content compared to that of cyolane treated rats. Values of thyroxine (T 4 ) and triiodothyronine (T 3 ) also fluctuated

  19. Multipathway organophosphorus pesticide exposures of preschool children living in agricultural and nonagricultural communities

    International Nuclear Information System (INIS)

    Lu Chensheng; Kedan, Golan; Fisker-Andersen, Jennifer; Kissel, J.C.; Fenske, R.A.

    2004-01-01

    Environmental measurements of organophosphorus (OP) pesticides were conducted in the homes of 13 children, who lived either in the Seattle metropolitan area or in the agricultural region of Washington State, to ascertain exposure through multiple pathways. Each home was sampled for two 24-h periods during two seasons, summer and fall. Samples included 24-h indoor air, drinking water, soil, house dust, and hand and toy wipes and 24-h duplicate diets. At least one OP pesticide was found in each of the matrices sampled except for drinking water. Half of the indoor air samples contained detectable levels of chlorpyrifos or diazinon. Detectable levels of diazinon and azinphosmethyl in house dust were found in most of the agricultural homes, whereas only diazinon was found in the Seattle homes in the summer. Quantifiable chlorpyrifos and azinphosmethyl were found on either agricultural children's hands or their toys. These findings suggest different exposure pathways for children living in agricultural and nonagricultural regions

  20. Engineering and introduction of de novo disulphide bridges in organophosphorus hydrolase enzyme for thermostability improvement.

    Science.gov (United States)

    Farnoosh, Gholamreza; Khajeh, Khosro; Latifi, Ali Mohammad; Aghamollaei, Hossein

    2016-12-01

    The organophosphorus hydrolase (OPH) has been used to degrade organophosphorus chemicals, as one of the most frequently used decontamination methods. Under chemical and thermal denaturing conditions, the enzyme has been shown to unfold. To utilize this enzyme in various applications, the thermal stability is of importance. The engineering of de novo disulphide bridges has been explored as a means to increase the thermal stability of enzymes in the rational method of protein engineering. In this study, Disulphide by Design software, homology modelling and molecular dynamics simulations were used to select appropriate amino acid pairs for the introduction of disulphide bridge to improve protein thermostability. The thermostability of the wild-type and three selected mutant enzymes were evaluated by half-life, delta G inactivation (ΔGi) and structural studies (fluorescence and far-UV CD analysis). Data analysis showed that half-life of A204C/T234C and T128C/E153C mutants were increased up to 4 and 24 min, respectively; however, for the G74C/A78C mutant, the half-life was decreased up to 9 min. For the T128C/E124C mutant, both thermal stability and Catalytic efficiency (kcat) were also increased. The half-life and ΔGi results were correlated to the obtained information from structural studies by circular dichroism (CD) spectrometry and extrinsic fluorescence experiments; as rigidity increased in A204C/T2234C and T128C/E153C mutants, half-life and ΔGi also increased. For G74C/A78C mutant, these parameters decreased due to its higher flexibility. The results were submitted a strong evidence for the possibility to improve the thermostability of OPH enzyme by introducing a disulphide bridge after bioinformatics design, even though this design would not be always successful.

  1. The solvent extraction of zinc, iron, and indium from chloride solutions by neutral organophosphorus compounds

    International Nuclear Information System (INIS)

    Preston, J.S.; Du Preez, A.C.

    1985-01-01

    The preparation of several neutral organophosphorus compounds and their evaluation as selective extractants for zinc in chloride media are described. The compounds belong to the series trialkyl phosphates (RO) 3 PO, dialkyl alkylphosphonates R'PO(OR) 2 , alkyl dialkylphosphinates R 2 'PO(OR), and trialkyl-phosphine oxides R 3 'PO. They were characterized by measurement of their physical properties (melting and boiling points, refractive indices, and densities), and their purities were confirmed by osmometric determination of their molecular masses; by carbon and hydrogen microanalysis; by the titrimetric determination of acidic impurities; and, for liquid products, by comparison of their experimental molar refractivities with empirical values. Metal-distribution equilibria were determined for solutions of the extractants in xylene and aqueous phase containing 0,5 to 5,0 M sodium chloride. Moderately good selectivities were shown for zinc(II) over iron(III), and excellent selectivities were shown for zinc(II) over iron(II), copper(II), lead(II), and cadmium(II). The extraction of indium(III) was similar to that of zinc(II). The extraction of zinc(III), iron(III), and indium(III) increased markedly through the series. (RO) 3 PO 2 2 'PO(OR) 3 'PO. The incorporation of phenyl groups into the compounds led to weaker extraction. The extracted complexes of zinc(II), iron(III), and indium(III) have the stoichiometries ZnCl 2 L 2 ,FeCl 3 L 2 (H 2 O), and InCl 3 L 2 (H 2 O) respectively, where L represents the neutral organophosphorus compound

  2. Divergent effects of postmortem ambient temperature on organophosphorus- and carbamate-inhibited brain cholinesterase activity in birds

    Science.gov (United States)

    Hill, E.F.

    1989-01-01

    Time- and temperature-dependent postmortem changes in inhibited brain cholinesterase (ChE) activity may confound diagnosis of field poisoning of wildlife by anticholinesterase pesticide. Carbamate-inhibited ChE activity may return to normal within 1 to 2 days of exposure of intact carcass to moderate ambient temperature (18-32C). Organophosphorus-inhibited ChE activity becomes more depressed over the same time. Uninhibited ChE activity was resilient to above freezing temperature to 32C for 1 day and 25C for 3 days. Carbamate- and organophosphorus-inhibited ChE can be separated by incubation of homogenate for 1 hour at physiological temperatures; carbamylated ChE can be readily reactivated while phosphorylated ChE cannot.

  3. Increased fetal endocardial echogenicity mimicking endocardial fibroelastosis following maternal organophosphorus poisoning and its complete regression in utero

    International Nuclear Information System (INIS)

    Balakumar, Karippaliyil; Misha, Kannan; Milind, Karippaliyil

    2013-01-01

    Fetal endocardial fibroelastosis (EFE) has been diagnosed by antenatal ultrasonography in the past few years. A typical case of isolated endocardial fibroelastosis is illustrated here, in a fetus of 22 weeks of gestational age exposed to maternal organophosphorus poisoning at 20 weeks. No other structural cardiac or other systemic anomalies were detected in this fetus. The abnormal fetal echocardiographic features mimicking endocardial fibroelastosis completely regressed after 14 weeks and a normal full-term baby was delivered. Postnatal echocardiogram showed normal cardiac parameters. The diagnostic features mimicking EFE following maternal organophosphorus poisoning at 20 weeks of gestational age and the subsequent complete reversal of these changes after 14 weeks of diagnosis are reported for the first time in the literature

  4. Synergistic Extraction of Copper from Nitrate Solutions Using β-Hydroxy-Naphthaldoxime and Organophosphorus Compounds into Carbon-Tetrachloride

    Science.gov (United States)

    Dey, Pulak; Basu, Sukalyan

    2011-12-01

    The extraction behavior of Cu(II) from an aqueous nitrate medium employing β-hydroxy-naphthaldoxime in carbon tetrachloride has been investigated in the presence of several organophosphorus donors like tri-octyl phosphine oxide, tri-butyl phosphine oxide, and tri-butyl phosphate at pH 1.5. The concentration of the metal was measured by atomic absorption spectrophotometry. Synergism was observed when neutral donor was added because of the formation of the adduct [Cu(L)2.(S)] in CCl4 (S denotes neutral donor). The equilibrium constants of the binary system using β-hydroxy-naphthaldoxime and the ternary system involving another addition of an organophosphorus compound were calculated from the extraction date obtained. Furthermore, the temperature dependence of the equilibrium constants was also investigated to evaluate standard enthalpy (Δ H°), entropy (Δ S°), and free energy (Δ G°) of the reactions proposed.

  5. Expression of organophosphorus-degradation gene ( opd) in aggregating and non-aggregating filamentous nitrogen-fixing cyanobacteria

    Science.gov (United States)

    Li, Qiong; Tang, Qing; Xu, Xudong; Gao, Hong

    2010-11-01

    Genetic engineering in filamentous N2-fixing cyanobacteria usually involves Anabaena sp. PCC 7120 and several other non-aggregating species. Mass culture and harvest of such species are more energy consuming relative to aggregating species. To establish a gene transfer system for aggregating species, we tested many species of Anabaena and Nostoc, and identified Nostoc muscorum FACHB244 as a species that can be genetically manipulated using the conjugative gene transfer system. To promote biodegradation of organophosphorus pollutants in aquatic environments, we introduced a plasmid containing the organophosphorus-degradation gene ( opd) into Anabaena sp. PCC 7120 and Nostoc muscorum FACHB244 by conjugation. The opd gene was driven by a strong promoter, P psbA . From both species, we obtained transgenic strains having organophosphorus-degradation activities. At 25°C, the whole-cell activities of the transgenic Anabaena and Nostoc strains were 0.163±0.001 and 0.289±0.042 unit/μg Chl a, respectively. However, most colonies resulting from the gene transfer showed no activity. PCR and DNA sequencing revealed deletions or rearrangements in the plasmid in some of the colonies. Expression of the green fluorescent protein gene from the same promoter in Anabaena sp. PCC 7120 showed similar results. These results suggest that there is the potential to promote the degradation of organophosphorus pollutants with transgenic cyanobacteria and that selection of high-expression transgenic colonies is important for genetic engineering of Anabaena and Nostoc species. For the first time, we established a gene transfer and expression system in an aggregating filamentous N2-fixing cyanobacterium. The genetic manipulation system of Nostoc muscorum FACHB244 could be utilized in the elimination of pollutants and large-scale production of valuable proteins or metabolites.

  6. Positively charged polysilsesquioxane/iodide lonic liquid as a quasi solid-state redox electrolyte for dye-sensitized photo electrochemical cells: infrared, 29 Si NMR, and electrical studies

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A new sol-gel precursor based on 1-methyl-3-[3-(trimethoxy- λ 4 -silylpropyl]-1 H -imidazolium iodide (MTMSPI + I − was synthesized and investigated as a potential novel quasi solid-state ionic liquid redox electrolyte for dye-synthesized photoelectrochemical (DSPEC cells of the Graetzel type. MTMSPI + I − was hydrolyzed with acidified water and the reaction products of the sol-gel condensation reactions assessed with the help of 29 Si NMR and infrared spectroscopic techniques. Results of the time-dependent spectra analyses showed the formation of positively charged polyhedral cube-like silsesquioxane species that still contained a small amount of silanol end groups, which were removed after heating at 200 ° C . After cooling, the resulting material formed is a tough, yellowish, and transparent solid, which could be reheated again and used for assembling DSPEC cells. The addition of iodine increased the specific conductivity of the hydrolyzed and nonhydrolyzed MTMSPI + I − , which we attributed to the formation of triiodide ions contributed to the conductivity via the Grotthus mechanism. DSPEC cells based on a titania-dye system with MTMSPI + I − electrolyte containing iodine (0.1 M reached an overall efficiency between 3.3–3.7%.

  7. [Determination of 44 organophosphorus pesticides in food by SPE disk extraction-capillary gas chromatography with pulsed flame photometric detection].

    Science.gov (United States)

    Luo, Xiao-Fei; Yang, Yuan; Sun, Cheng-Jun

    2012-01-01

    To develop a method for the simultaneous determination of 44 organophosphorus pesticides in food by SPE disk extraction-capillary gas chromatography with pulsed flame photometric detection. Organophosphorus pesticides in food were extracted ultrasonically with water. Then the extract was cleaned-up with SPE disk and eluted with ethyl acetate. Finally the eluent was condensed to 1mL under N2 at 55 degrees C. Gas chromatography was applied for quantitative detection of the organophosphorus pesticides in the sample. The linear range of the method for all the pesticides were in the range of 0.01-0.5 mg/kg with correlation coefficients of 0.992-1.000. The detection limits of the method were in the range of 0.0005-0.01 mg/kg. The recoveries for most pesticides were 60%-120% with relative standard deviations of less than 15%. The method is simple, sensitive, environmentally friendly and suitable for the determination of organophosphorous pesticides in food.

  8. Identification and isolation of bacteria containing OPH enzyme for biodegradation of organophosphorus pesticide diazinon from contaminated agricultural soil

    Directory of Open Access Journals (Sweden)

    Sara Mobarakpoor

    2015-04-01

    Full Text Available Background: Organophosphorus insecticide diazinon has been widely used in agriculture and has the ability to transfer and accumulate in soil, water and animal tissues, and to induce toxicity in plants, animals and humans. In humans, diazinon inhibits nerve transmission by inactivating acetylcholinesterase enzyme. The present study was carried out to identify bacteria containing OPH enzyme for biodegradation of diazinon from contaminated agricultural soil. Methods: In this study, 8 contaminated agricultural soil samples that were exposed to pesticides, especially diazinon in the last two decades, were collected from the farms of Hamedan province. After preparing the media, for isolation of several bacterial strains containing OPH enzyme that are capable of biodegrading organophosphorus pesticides by diazinon enzymatic hydrolysis, bacterial genomic DNA extraction, plasmid product sequencing, phylogenetic sequence processing and phylogenetic tree drawing were carried out. Results: Eight bacterial strains, capable of secreting OPH enzyme, were isolated from soil samples, one of which named BS-1 with 86% similarity to Bacillus safensis displayed the highest organophosphate-hydrolyzing capability and can be used as a source of carbon and phosphorus. Conclusion: It can be concluded that the isolated bacterial strain identified in this study with OPH enzyme secretion has the potential for biodegradation of organophosphorus pesticides, especially diazinon in invitro conditions. Also, further studies such as the environmental stability and interaction, production strategies, safety, cost-benefit, environmental destructive parameters, and, toxicological, genetic and biochemical aspects are recommended prior to the application of bacterial strains in the field-scale bioremediation.

  9. Net charge fluctuations and local charge compensation

    International Nuclear Information System (INIS)

    Fu Jinghua

    2006-01-01

    We propose net charge fluctuation as a measure of local charge correlation length. It is demonstrated that, in terms of a schematic multiperipheral model, net charge fluctuation satisfies the same Quigg-Thomas relation as satisfied by charge transfer fluctuation. Net charge fluctuations measured in finite rapidity windows depend on both the local charge correlation length and the size of the observation window. When the observation window is larger than the local charge correlation length, the net charge fluctuation only depends on the local charge correlation length, while forward-backward charge fluctuations always have strong dependence on the observation window size. Net charge fluctuations and forward-backward charge fluctuations measured in the present heavy ion experiments show characteristic features similar to those from multiperipheral models. But the data cannot all be understood within this simple model

  10. Organophosphorus pesticide and ester analysis by using comprehensive two-dimensional gas chromatography with flame photometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiangping; Li, Dengkun; Li, Jiequan [Nanjing Centre for Disease Control and Prevention, Zizhulin Street, Gulou 210003, Nanjing (China); Rose, Gavin [Department of Environment and Primary Industries, Macleod Centre, Ernest Jones Drive, Macleod, Vic 3085 (Australia); Marriott, Philip J., E-mail: philip.marriott@monash.edu [Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton 3800 (Australia)

    2013-12-15

    Highlights: • GC × GC-FPD(P-mode) was applied to detection of 37 phosphorus (P)-containing compounds. • The method improves resolution of P-compounds that coelute in the first dimension. • P-compounds are analyzed with excellent sensitivity supported by cryogenic modulation. • The FPD(P-mode) selectivity allows analysis in high hydrocarbon (H/C) matrix. • Soil samples and spiked chemical weapon compounds in H/C matrix are readily screened. -- Abstract: Thirty-seven phosphorus (P)-containing compounds comprising organophosphorus pesticides and organophosphate esters were analyzed by using comprehensive two-dimensional gas chromatography with flame photometric detection in P mode (GC × GC-FPD(P)), with a non-polar/moderately polar column set. A suitable modulation temperature and period was chosen based on experimental observation. A number of co-eluting peak pairs on the {sup 1}D column were well separated in 2D space. Excellent FPD(P) detection selectivity, responding to compounds containing the P atom, produces clear 2D GC × GC plots with little interference from complex hydrocarbon matrices. Limits of detection (LOD) were within the range of 0.0021–0.048 μmol L{sup −1}, and linear calibration correlation coefficients (R{sup 2}) for all 37 P-compounds were at least 0.998. The P-compounds were spiked in 2% diesel and good reproducibility for their response areas and retention times was obtained. Spiked recoveries were 88%–157% for 5 μg L{sup −1} and 80%–138% for 10 μg L{sup −1} spiked levels. Both {sup 1}t{sub R} and {sup 2}t{sub R} shifts were noted when the content of diesel was in excess of 5% in the matrix. Soil samples were analyzed by using the developed method; some P-compounds were positively detected. In general, this study shows that GC × GC-FPD(P) is an accurate, sensitive and simple method for P-compound analysis in complicated environmental samples.

  11. Model improvements to simulate charging in SEM

    Science.gov (United States)

    Arat, K. T.; Klimpel, T.; Hagen, C. W.

    2018-03-01

    Charging of insulators is a complex phenomenon to simulate since the accuracy of the simulations is very sensitive to the interaction of electrons with matter and electric fields. In this study, we report model improvements for a previously developed Monte-Carlo simulator to more accurately simulate samples that charge. The improvements include both modelling of low energy electron scattering and charging of insulators. The new first-principle scattering models provide a more realistic charge distribution cloud in the material, and a better match between non-charging simulations and experimental results. Improvements on charging models mainly focus on redistribution of the charge carriers in the material with an induced conductivity (EBIC) and a breakdown model, leading to a smoother distribution of the charges. Combined with a more accurate tracing of low energy electrons in the electric field, we managed to reproduce the dynamically changing charging contrast due to an induced positive surface potential.

  12. Thunderstorm Charge Structures Producing Negative Gigantic Jets

    Science.gov (United States)

    Boggs, L.; Liu, N.; Riousset, J. A.; Shi, F.; Rassoul, H.

    2016-12-01

    Here we present observational and modeling results that provide insight into thunderstorm charge structures that produce gigantic jet discharges. The observational results include data from four different thunderstorms producing 9 negative gigantic jets from 2010 to 2014. We used radar, very high frequency (VHF) and low frequency (LF) lightning data to analyze the storm characteristics, charge structures, and lightning activity when the gigantic jets emerged from the parent thunderstorms. A detailed investigation of the evolution of one of the charge structures by analyzing the VHF data is also presented. The newly found charge structure obtained from the observations was analyzed with fractal modeling and compared with previous fractal modeling studies [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008; Riousset et al., JGR, 115, A00E10, 2010] of gigantic jet discharges. Our work finds that for normal polarity thunderstorms, gigantic jet charge structures feature a narrow upper positive charge region over a wide middle negative charge region. There also likely exists a `ring' of negative screening charge located around the perimeter of the upper positive charge. This is different from previously thought charge structures of the storms producing gigantic jets, which had a very wide upper positive charge region over a wide middle negative charge region, with a very small negative screening layer covering the cloud top. The newly found charge structure results in leader discharge trees in the fractal simulations that closely match the parent flashes of gigantic jets inside and outside the thundercloud. The previously used charge structures, while vital to the understanding of gigantic jet initiation and the role of charge imbalances inside the cloud, do not produce leader discharge trees that agree with observed gigantic jet discharges.Finally, the newly discovered gigantic jet charge structures are formed near the end of a convective pulse [Meyer et al., JGR, 118

  13. Charge transport problem

    International Nuclear Information System (INIS)

    Lee, E.P.

    1977-01-01

    In a recent report (UCID 17346, ''Relativistic Particle Beam in a Semi-Infinite Axially Symmetric conducting channel extending from a perfectly conducting plane,'' Dec. 13, 1976) Cooper and Neil demonstrate that the net charge transported by a beam pulse injected into a channel of finite conductivity equals the charge of the beam itself. The channel is taken to be infinite in the positive z direction, has finite radius and is terminated by a conducting ground plane at z =0. This result is not an obvious one, and it is restricted in its applicability by the special model assumed for the channel. It is the purpose to explain the result of Cooper and Neil in more qualitative terms and to make similar calculations using several other channel models. It must be emphasized that these calculations are not concerned with the fate of the transported charge after the pulse has stopped, but rather with how much charge leaves the ground plane assuming the pulse does not stop

  14. STUDY OF CLINICAL PROFILE AND OUTCOME OF ORGANOPHOSPHORUS POISONING IN RELATION TO PSEUDOCHOLINESTERASE LEVEL

    Directory of Open Access Journals (Sweden)

    Rajyalakshmi

    2017-11-01

    Full Text Available BACKGROUND The state of Andhra Pradesh, particularly the coastal districts are an area of intensive agricultural production. Pesticide use is high, and the state has one of the highest reported rates of pesticide poisoning in India. The resources for treating this number of cases in government hospitals are limited and likely to have an impact on patient outcome. The present study was carried out in one such hospital of the state. Amongst these pesticides, insecticides constitute an important group, and organophosphorus compounds are possibly the insecticides widely used, all over the world. MATERIALS AND METHODS Hundred patients of pesticide poisoning admitted into the medical ward of Government General Hospital, Kakinada during the period of August 2010 to July 2014 were studied. Detailed history was taken in each case from patient and attendants. A meticulous physical examination was done on each of them at the time of admission. The diagnosis of poisoning was suspected from the characteristic garlic and kerosene like odour, characteristic signs and symptoms of poisoning and corroborative evidence collected in the form of packets or containers obtained from the site by family members or bystanders. RESULTS Out of the 14 patients who died, 11 died due to organophosphate poisoning, 2 patients died due to organochlorine poisoning and 1 patient died due to herbicide poisoning. Out of the 11 patients who expired due to organophosphate poisoning, 10 patients had pseudocholinesterase value ≤1 unit/mL. The remaining one (1 patient who died, had a pseudocholinesterase value of 2.2 units/mL. Of the 11 patients who died due to organophosphate poisoning, Monocrotophos recorded highest number of deaths (6 cases, followed by dimethoate, which was responsible for 2 deaths. Methyl parathion, Profenophos and Chlorpyriphos caused 1 death each. An organochlorine compound, Endosulfan caused 2 deaths. Paraquat, a herbicide was responsible for 1 death

  15. [Research on rapid and quantitative detection method for organophosphorus pesticide residue].

    Science.gov (United States)

    Sun, Yuan-Xin; Chen, Bing-Tai; Yi, Sen; Sun, Ming

    2014-05-01

    The methods of physical-chemical inspection is adopted in the traditional pesticide residue detection, which require a lot of pretreatment processes, are time-consuming and complicated. In the present study, the authors take chlorpyrifos applied widely in the present agricultural field as the research object and propose a rapid and quantitative detection method for organophosphorus pesticide residues. At first, according to the chemical characteristics of chlorpyrifos and comprehensive chromogenic effect of several colorimetric reagents and secondary pollution, the pretreatment of the scheme of chromogenic reaction of chlorpyrifos with resorcin in a weak alkaline environment was determined. Secondly, by analyzing Uv-Vis spectrum data of chlorpyrifos samples whose content were between 0. 5 and 400 mg kg-1, it was confirmed that the characteristic information after the color reaction mainly was concentrated among 360 approximately 400 nm. Thirdly, the full spectrum forecasting model was established based on the partial least squares, whose correlation coefficient of calibration was 0. 999 6, correlation coefficient of prediction reached 0. 995 6, standard deviation of calibration (RMSEC) was 2. 814 7 mg kg-1, and standard deviation of verification (RMSEP) was 8. 012 4 mg kg-1. Fourthly, the wavelengths whose center wavelength is 400 nm was extracted as characteristic region to build a forecasting model, whose correlation coefficient of calibration was 0. 999 6, correlation coefficient of prediction reached 0. 999 3, standard deviation of calibration (RMSEC) was 2. 566 7 mg kg-1 , standard deviation of verification (RMSEP) was 4. 886 6 mg kg-1, respectively. At last, by analyzing the near infrared spectrum data of chlorpyrifos samples with contents between 0. 5 and 16 mg kg-1, the authors found that although the characteristics of the chromogenic functional group are not obvious, the change of absorption peaks of resorcin itself in the neighborhood of 5 200 cm

  16. Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eungtaek; Kim, Choong-Ki; Lee, Myung Keun; Bang, Tewook; Choi, Yang-Kyu; Choi, Kyung Cheol, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr [School of Electrical Engineering, KAIST, Daejeon 34141 (Korea, Republic of); Park, Sang-Hee Ko, E-mail: shkp@kaist.ac.kr, E-mail: kyungcc@kaist.ac.kr [Department of Material Science and Engineering, KAIST, Daejeon 34141 (Korea, Republic of)

    2016-05-02

    We investigated the positive-bias stress (PBS) instability of thin film transistors (TFTs) composed of different types of first-gate insulators, which serve as a protection layer of the active surface. Two different deposition methods, i.e., the thermal atomic layer deposition (THALD) and plasma-enhanced ALD (PEALD) of Al{sub 2}O{sub 3}, were applied for the deposition of the first GI. When THALD was used to deposit the GI, amorphous indium-gallium-zinc oxide (a-IGZO) TFTs showed superior stability characteristics under PBS. For example, the threshold voltage shift (ΔV{sub th}) was 0 V even after a PBS time (t{sub stress}) of 3000 s under a gate voltage (V{sub G}) condition of 5 V (with an electrical field of 1.25 MV/cm). On the other hand, when the first GI was deposited by PEALD, the ΔV{sub th} value of a-IGZO TFTs was 0.82 V after undergoing an identical amount of PBS. In order to interpret the disparate ΔV{sub th} values resulting from PBS quantitatively, the average oxide charge trap density (N{sub T}) in the GI and its spatial distribution were investigated through low-frequency noise characterizations. A higher N{sub T} resulted during in the PEALD type GI than in the THALD case. Specifically, the PEALD process on a-IGZO layer surface led to an increasing trend of N{sub T} near the GI/a-IGZO interface compared to bulk GI owing to oxygen plasma damage on the a-IGZO surface.

  17. Influence of the charge trap density distribution in a gate insulator on the positive-bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors

    International Nuclear Information System (INIS)

    Kim, Eungtaek; Kim, Choong-Ki; Lee, Myung Keun; Bang, Tewook; Choi, Yang-Kyu; Choi, Kyung Cheol; Park, Sang-Hee Ko

    2016-01-01

    We investigated the positive-bias stress (PBS) instability of thin film transistors (TFTs) composed of different types of first-gate insulators, which serve as a protection layer of the active surface. Two different deposition methods, i.e., the thermal atomic layer deposition (THALD) and plasma-enhanced ALD (PEALD) of Al_2O_3, were applied for the deposition of the first GI. When THALD was used to deposit the GI, amorphous indium-gallium-zinc oxide (a-IGZO) TFTs showed superior stability characteristics under PBS. For example, the threshold voltage shift (ΔV_t_h) was 0 V even after a PBS time (t_s_t_r_e_s_s) of 3000 s under a gate voltage (V_G) condition of 5 V (with an electrical field of 1.25 MV/cm). On the other hand, when the first GI was deposited by PEALD, the ΔV_t_h value of a-IGZO TFTs was 0.82 V after undergoing an identical amount of PBS. In order to interpret the disparate ΔV_t_h values resulting from PBS quantitatively, the average oxide charge trap density (N_T) in the GI and its spatial distribution were investigated through low-frequency noise characterizations. A higher N_T resulted during in the PEALD type GI than in the THALD case. Specifically, the PEALD process on a-IGZO layer surface led to an increasing trend of N_T near the GI/a-IGZO interface compared to bulk GI owing to oxygen plasma damage on the a-IGZO surface.

  18. Gastric Lavage in Acute Organophosphorus Pesticide poisoning (GLAOP – a randomised controlled trial of multiple vs. single gastric lavage in unselected acute organophosphorus pesticide poisoning

    Directory of Open Access Journals (Sweden)

    Cao YuPing

    2006-10-01

    Full Text Available Abstract Background Organophosphorus (OP pesticide poisoning is the most common form of pesticide poisoning in many Asian countries. Guidelines in western countries for management of poisoning indicate that gastric lavage should be performed only if two criteria are met: within one hour of poison ingestion and substantial ingested amount. But the evidence on which these guidelines are based is from medicine overdoses in developed countries and may be irrelevant to OP poisoning in Asia. Chinese clinical experience suggests that OP remains in the stomach for several hours or even days after ingestion. Thus, there may be reasons for doing single or multiple gastric lavages for OP poisoning. There have been no randomised controlled trials (RCTs to assess this practice of multiple lavages. Since it is currently standard therapy in China, we cannot perform a RCT of no lavage vs. a single lavage vs. multiple lavages. We will compare a single gastric lavage with three gastric lavages as the first stage to assess the role of gastric lavage in OP poisoning. Methods/Design We have designed an RCT assessing the effectiveness of multiple gastric lavages in adult OP self-poisoning patients admitted to three Chinese hospitals within 12 hrs of ingestion. Patients will be randomised to standard treatment plus either a single gastric lavage on admission or three gastric lavages at four hour intervals. The primary outcome is in-hospital mortality. Analysis will be on an intention-to-treat basis. On the basis of the historical incidence of OP at the study sites, we expect to enroll 908 patients over three years. This projected sample size provides sufficient power to evaluate the death rate; and a variety of other exposure and outcome variables, including particular OPs and ingestion time. Changes of OP level will be analyzed in order to provide some toxic kinetic data. Discussion the GLAOP study is a novel, prospective cohort study that will explore to the toxic

  19. Fuel charging machine

    International Nuclear Information System (INIS)

    Uchikawa, Sadao.

    1978-01-01

    Purpose: To enable continuous fuel discharging and charging steps in a bwr type reactor by effecting positioning only for once by providing a plurality of fuel assembly grippers and their drives co-axially on a rotatable surface. Constitution: A plurality of fuel assembly grippers and their drives are provided co-axially on a rotatable surface. For example, a gripper A, a drive B, a gripper C and a drive D are arranged co-axially in symmetric positions on a disk rotated on rails by wheels and rotational drives. A new fuel in a fuel pool is gripped by the gripper A and transported above the reactor core. Then, the disk is positioned so that the gripper C can grip the spent fuel in the core, and the fuel to be discharged is gripped and raised by the gripper C. Then the disk is rotated by 180 0 and the new fuel in the gripper A is charged into the position from which the old fuel has been discharged and, finally, the discharged fuel is sent to the fuel pool for storage. (Seki, T.)

  20. CHARGE Association

    Directory of Open Access Journals (Sweden)

    Semanti Chakraborty

    2012-01-01

    Full Text Available We present here a case of 17-year-old boy from Kolkata presenting with obesity, bilateral gynecomastia, mental retardation, and hypogonadotrophic hypogonadism. The patient weighed 70 kg and was of 153 cm height. Facial asymmetry (unilateral facial palsy, gynecomastia, decreased pubic and axillary hair, small penis, decreased right testicular volume, non-palpable left testis, and right-sided congenital inguinal hernia was present. The patient also had disc coloboma, convergent squint, microcornea, microphthalmia, pseudohypertelorism, low set ears, short neck, and choanalatresia. He had h/o VSD repaired with patch. Laboratory examination revealed haemoglobin 9.9 mg/dl, urea 24 mg/dl, creatinine 0.68 mg/dl. IGF1 77.80 ng/ml (decreased for age, GH <0.05 ng/ml, testosterone 0.25 ng/ml, FSH-0.95 ΅IU/ml, LH 0.60 ΅IU/ml. ACTH, 8:00 A.M cortisol, FT3, FT4, TSH, estradiol, DHEA-S, lipid profile, and LFT was within normal limits. Prolactin was elevated at 38.50 ng/ml. The patient′s karyotype was 46XY. Echocardiography revealed ventricularseptal defect closed with patch, grade 1 aortic regurgitation, and ejection fraction 67%. Ultrasound testis showed small right testis within scrotal sac and undescended left testis within left inguinal canal. CT scan paranasal sinuses revealed choanalatresia and deviation of nasal septum to the right. Sonomammography revealed bilateral proliferation of fibroglandular elements predominantly in subareoalar region of breasts. MRI of brain and pituitary region revealed markedly atrophic pituitary gland parenchyma with preserved infundibulum and hypothalamus and widened suprasellar cistern. The CHARGE association is an increasingly recognized non-random pattern of congenital anomalies comprising of coloboma, heart defect, choanal atresia, retarded growth and development, genital hypoplasia, ear abnormalities, and/or deafness. [1] These anomalies have a higher probability of occurring together. In this report, we have

  1. Organophosphorus flame retardants in mangrove sediments from the Pearl River Estuary, South China.

    Science.gov (United States)

    Hu, Yong-Xia; Sun, Yu-Xin; Li, Xiao; Xu, Wei-Hai; Zhang, Ying; Luo, Xiao-Jun; Dai, Shou-Hui; Xu, Xiang-Rong; Mai, Bi-Xian

    2017-08-01

    Forty-eight surface sediments were collected from three mangrove wetlands in the Pearl River Estuary (PRE) of South China to investigate the distribution of organophosphorus flame retardants (OPFRs) and the relationship between OPFRs and microbial community structure determined by phospholipid fatty acid. Concentrations of ΣOPFRs in mangrove sediments of the PRE ranged from 13.2 to 377.1 ng g -1 dry weight. Levels of ΣOPFRs in mangrove sediments from Shenzhen and Guangzhou were significantly higher than those from Zhuhai, indicating that OPFRs were linked to industrialization and urbanization. Tris(chloropropyl)phosphate was the predominant profile of OPFRs in mangrove sediments from Shenzhen (38.9%) and Guangzhou (35.0%), while the composition profile of OPFRs in mangrove sediments from Zhuhai was dominated by tris(2-chloroethyl) phosphate (25.5%). The mass inventories of OPFRs in the mangrove sediments of Guangzhou, Zhuhai and Shenzhen were 439.5, 133.5 and 662.3 ng cm -2 , respectively. Redundancy analysis revealed that OPFRs induced a shift in the structure of mangrove sediment microbial community and the variations were significantly correlated with tris(1,3-dichloro-2-propyl)phosphate and tris(2-butoxyethyl) phosphate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Sensitive spectrophotometric methods for determination of some organophosphorus pesticides in vegetable samples

    Directory of Open Access Journals (Sweden)

    MAGDA A. AKL

    2010-03-01

    Full Text Available Three rapid, simple, reproducible and sensitive spectrophotometric methods (A, B and C are described for the determination of two organophosphorus pesticides, (malathion and dimethoate in formulations and vegetable samples. The methods A and B involve the addition of an excess of Ce4+ into sulphuric acid medium and the determination of the unreacted oxidant by decreasing the red color of chromotrope 2R (C2R at a suitable lmax = 528 nm for method A, or a decrease in the orange pink color of rhodamine 6G (Rh6G at a suitable lmax = = 525 nm. The method C is based on the oxidation of malathion or dimethoate with the slight excess of N-bromosuccinimide (NBS and the determination of unreacted oxidant by reacting it with amaranth dye (AM in hydrochloric acid medium at a suitable lmax = 520 nm. A regression analysis of Beer-Lambert plots showed a good correlation in the concentration range of 0.1-4.2 μg mL−1. The apparent molar absorptivity, Sandell sensitivity, the detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration ranges are 0.25-4.0 μg mL−1. The developed methods were successfully applied to the determination of malathion, and dimethoate in their formulations and environmental vegetable samples.

  3. Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry.

    Science.gov (United States)

    Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

    2015-06-15

    In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM>FT>PFF>PCF>IFP>CFVP>FNT⩾DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R(2)=0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Susceptibility of nine organophosphorus pesticides in skimmed milk towards inoculated lactic acid bacteria and yogurt starters.

    Science.gov (United States)

    Zhou, Xin-Wei; Zhao, Xin-Huai

    2015-01-01

    Previous research has shown that fresh milk might be polluted by some organophosphorus pesticides (OPPs). In this study the dissipation of nine OPPs, namely chlorpyrifos, chlorpyrifos-methyl, diazinon, dichlorvos, fenthion, malathion, phorate, pirimiphos-methyl and trichlorphon, in skimmed milk was investigated to clarify their susceptibility towards lactic acid bacteria (LAB) and yogurt starters. Skimmed milk was spiked with nine OPPs, inoculated with five strains of LAB and two commercial yogurt starters at 42 °C for 24 and 5 h respectively and subjected to quantitative OPP analysis by gas chromatography. Degradation kinetic constants of these OPPs were calculated based on a first-order reaction model. OPP dissipation in the milk was enhanced by the inoculated strains and starters, resulting in OPP concentrations decreasing by 7.0-64.6 and 7.4-19.2% respectively. Totally, the nine OPPs were more susceptible to Lactobacillus bulgaricus, as it enhanced their degradation rate constants by 18.3-133.3%. Higher phosphatase production of the assayed stains was observed to bring about greater OPP degradation in the milk. Both LAB and yogurt starters could enhance OPP dissipation in skimmed milk, with the nine OPPs studied having different susceptibilities towards them. Phosphatase was a key factor governing OPP dissipation. The LAB of higher phosphatase production have more potential to decrease OPPs in fermented foods. © 2014 Society of Chemical Industry.

  5. A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas

    Science.gov (United States)

    He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

    2018-03-01

    Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

  6. Determination of organophosphorus pesticides using molecularly imprinted polymer solid phase extraction

    International Nuclear Information System (INIS)

    Mohd Marsin Sanagi; Syairah Salleh; Wan Aini Wan Ibrahim

    2011-01-01

    Molecularly imprinted polymer solid phase extraction (MIP-SPE) method has been developed for the determination of organophosphorus pesticides (OPPs) in water samples. The MIP was prepared by thermo-polymerization method using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, acetonitrile as porogenic solvent and quinalphos as the template molecule. The three OPPs (diazinon, quinalphos and chloropyrifos) were selected as target analytes as they are widely used in agriculture sector. Various parameters affecting the extraction efficiency of the imprinted polymers have been evaluated to optimize the selective preconcentration of OPPs from aqueous samples. The characteristics of the MIP-SPE method were validated by high performance liquid chromatography (HPLC). The accuracy and selectivity of the MIP-SPE process developed were verified using non-imprinted polymer solid phase extraction (NIP-SPE) and a commercial C 18 -SPE was used for comparison. The recoveries of the target analytes obtained using the MIPs as the solid phase sorbent ranged from 83% to 98% (RSDs 1.05 - 1.98 %; n=3) for water sample. The developed MIP-SPE method demonstrates that it could be applied for the determination of OPPs in water samples. (author)

  7. Competitive immunochromatographic assay for the detection of the organophosphorus pesticide chlorpyrifos

    Science.gov (United States)

    Kim, Young Ah; Lee, Eun-Hye; Kim, Kwang-Ok; Lee, Yong Tae; Hammock, Bruce D.; Lee, Hye-Sung

    2014-01-01

    An immunochromatographic assay (ICA) based on competitive antigen-coated format using colloidal gold as the label was developed for the detection of the organophosphorus insecticide chlorpyrifos. The ICA test strip consisted of a membrane with a detection zone, a sample pad and an absorbent pad. The membrane was separately coated with chlorpyrifos hapten-OVA conjugate (test line) and anti-mouse IgG (control line). Based on the fact that the competition is between the migrating analyte in the sample and the analyte hapten immobilized on the test strip for the binding sites of the antibody-colloidal gold (Ab-CG) conjugate migrating on the test strip, this study suggests that the relative migration speed between the two migrating substances is a critically important factor for the sensitive detection by competitive ICA. This criterion was utilized for the confirmation of appropriateness of a nitrocellulose (NC) membrane for chlorpyrifos ICA. The detection limit of the ICA for chlorpyrifos standard and chlorpyrifos spiked into agricultural samples were 10 and 50 ng mL−1, respectively. The assay time for the ICA test was less than 10 min, suitable for rapid on-site testing of chlorpyrifos. PMID:21504817

  8. Removal of actinides from nuclear fuel reprocessing waste solutions with bidentate organophosphorus extractants

    International Nuclear Information System (INIS)

    Schulz, W.W.; McIsaac, L.D.

    1975-08-01

    The neutral bidentate organophosphorus reagents DBDECMP (dibutyl-N,N-diethylcarbamylmethylenephosphonate) and its dihexyl analogue DHDECMP are candidate extractants for removal of actinides from certain acidic waste streams produced at the U. S. ERDA Hanford and Idaho Falls sites. Various chemical and physical properties including availability, cost, purification, alpha radiolysis, and aqueous phase solubility of DBDECMP and DHDECMP are reviewed. A conceptual flowsheet employing a 15 percent DBDECMP (or DHDECMP)--CCl 4 extractant for removal (and recovery) of Am and Pu from Hanford's Plutonium Reclamation Facility acid waste stream (CAW solution) was successfully demonstrated in laboratory-scale mixer-settler tests; this extraction scheme can be used to produce an actinide-free waste. A 30 percent DBDECMP-xylene flowsheet is being tested at the Idaho Falls site for removal of U, Np, Pu, and Am from Idaho Chemical Processing Plant first-cycle high-level raffinate to produce an actinide-free (less than 10 nCi alpha activity/gram) waste. (auth)

  9. Improvement of Some Biochemical Activities of Rats Treated with The Organophosphorus Insecticide Cytrolane Using Soyabean

    International Nuclear Information System (INIS)

    Abdel-Fattah, A.M.; Elmahdy, A.A.

    2005-01-01

    This Study aims to evaluate the role of soyabean diet in improvement of some biochemical activities of female rats received daily oral dose 0.89 mg/kg (1/10 LD 50 )of cytrolane as organophosphorus insecticide on some biochemical activities in female rats for ten consecutive days. Prior pesticide administration, female rats received soyabean at dose 58 g/kg body weight for 2 and 4 weeks. Under the effect of cytrolane administration, the results showed significant increase in serum triglycerides, total cholesterol, HDL-cholesterol and CPK mean levels. Total serum protein and progesterone levels were significantly decreased compared to the control. On the other hand, by the administration of soyabean prior cytrolane, it reduced considerably the changes produced by cytrolane on levels of serum cholesterol, triglyceride, HDL-cholesterol which decreased more or less compared to control, total protein level was within normal value. Also, serum progesterone concentration increased. Therefore, soyabean administration accelerated the normalization and improvement processes of the altered lipid profiles, protein and progesterone hormone

  10. A ratiometric fluorescent quantum dots based biosensor for organophosphorus pesticides detection by inner-filter effect.

    Science.gov (United States)

    Yan, Xu; Li, Hongxia; Han, Xiaosong; Su, Xingguang

    2015-12-15

    In this work, we develop a novel and sensitive sensor for the detection of organophosphorus pesticides based on the inner-filter effect (IFE) between gold nanoparticles (AuNPs) and ratiometric fluorescent quantum dots (RF-QDs). The RF-QDs has been designed by hybridizing two differently colored CdTe QDs, in which the red emissive QDs entrapped in the silica sphere acting as the reference signal, and the green emissive QDs covalently attached on the silica surface serving as the response signal.The fluorescence of RF-QDs could be quenched by AuNPs based on IFE. Protamine could effectively turn on the fluorescence due to the electrostatic attraction between protamine and AuNPs. Trypsin can easily hydrolyze protamine, leading to the quench of the fluorescence. Then, the fluorescence could be recovered again by the addition of parathion-methyl (PM) which could inhibit the activity of trypsin. By measuring the fluorescence of RF-QDs, the inhibition efficiency of PM to trypsin activity was evaluated. Under the optimized conditions, the inhibition efficiency was proportional to the logarithm of PM concentration in the range of 0.04-400 ng mL(-1), with a detection limit of 0.018 ng mL(-1). Furthermore, the simple and convenient method had been used for PM detection in environmental and agricultural samples with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Organophosphorus pesticides effect on early stages of the axolotl Ambystoma mexicanum (Amphibia: Caudata).

    Science.gov (United States)

    Robles-Mendoza, C; García-Basilio, C; Cram-Heydrich, S; Hernández-Quiroz, M; Vanegas-Pérez, C

    2009-02-01

    Ambystoma mexicanum is an endemic salamander of Xochimilco, a wetland of the basin of Mexico valley. Nowadays, axolotl populations are decreasing due environmental stressors. Particularly, studies about organophosphorus pesticides (OPPs; i.e. chlorpyrifos and malathion) toxicity are of great importance due to their intensive use in agricultural activities in Xochimilco. Thus, the aim of this study was to evaluate under controlled conditions the toxicity of chlorpyrifos (CPF) and malathion (MLT) on embryos and larvae (stage 44 and 54) of A. mexicanum. Embryos and larvae were exposure 96h from 0.5 to 3mg CPFL(-1) and from 10 to 30mg MLTL(-1) in independent tests. Embryos at the end of this period were maintained 9d without pesticide in order to identify possible recuperation. Differences obtained in mortality, hatching success, development, morphological abnormalities, behaviour and activity, suggest that toxicity of CPF and MLT differs in embryos and larval stages. Embryos were less sensitive to OPPs acute exposure than axolotl larvae; additionally, toxicity of CPF in larval stages was greater than MLT. On the other hand, data obtained in axolotl embryos during the period of recuperation to CPF in particular as delay and inhibition of development, malformations and success of hatching, indicated that these responses turned out more sensitive than mortality. This study allowed to identify the toxicological potential of OPPs on early developmental stages of A. mexicanum and it is a valuable contribution for the future management of the axolotl wild population.

  12. Biosensors and their applications in detection of organophosphorus pesticides in the environment.

    Science.gov (United States)

    Hassani, Shokoufeh; Momtaz, Saeideh; Vakhshiteh, Faezeh; Maghsoudi, Armin Salek; Ganjali, Mohammad Reza; Norouzi, Parviz; Abdollahi, Mohammad

    2017-01-01

    This review discusses the past and recent advancements of biosensors focusing on detection of organophosphorus pesticides (OPs) due to their exceptional use during the last decades. Apart from agricultural benefits, OPs also impose adverse toxicological effects on animal and human population. Conventional approaches such as chromatographic techniques used for pesticide detection are associated with several limitations. A biosensor technology is unique due to the detection sensitivity, selectivity, remarkable performance capabilities, simplicity and on-site operation, fabrication and incorporation with nanomaterials. This study also provided specifications of the most OPs biosensors reported until today based on their transducer system. In addition, we highlighted the application of advanced complementary materials and analysis techniques in OPs detection systems. The availability of these new materials associated with new sensing techniques has led to introduction of easy-to-use analytical tools of high sensitivity and specificity in the design and construction of OPs biosensors. In this review, we elaborated the achievements in sensing systems concerning innovative nanomaterials and analytical techniques with emphasis on OPs.

  13. New Cinchona Oximes Evaluated as Reactivators of Acetylcholinesterase and Butyrylcholinesterase Inhibited by Organophosphorus Compounds

    Directory of Open Access Journals (Sweden)

    Maja Katalinić

    2017-07-01

    Full Text Available For the last six decades, researchers have been focused on finding efficient reactivators of organophosphorus compound (OP-inhibited acetylcholinesterase (AChE and butyrylcholinesterase (BChE. In this study, we have focused our research on a new oxime scaffold based on the Cinchona structure since it was proven to fit the cholinesterases active site and reversibly inhibit their activity. Three Cinchona oximes (C1, C2, and C3, derivatives of the 9-oxocinchonidine, were synthesized and investigated in reactivation of various OP-inhibited AChE and BChE. As the results showed, the tested oximes were more efficient in the reactivation of BChE and they reactivated enzyme activity to up to 70% with reactivation rates similar to known pyridinium oximes used as antidotes in medical practice today. Furthermore, the oximes showed selectivity towards binding to the BChE active site and the determined enzyme-oxime dissociation constants supported work on the future development of inhibitors in other targeted studies (e.g., in treatment of neurodegenerative disease. Also, we monitored the cytotoxic effect of Cinchona oximes on two cell lines Hep G2 and SH-SY5Y to determine the possible limits for in vivo application. The cytotoxicity results support future studies of these compounds as long as their biological activity is targeted in the lower micromolar range.

  14. Catalytic Characteristics of New Antibacterials Based on Hexahistidine-Containing Organophosphorus Hydrolase

    Directory of Open Access Journals (Sweden)

    Olga Maslova

    2017-09-01

    Full Text Available Catalytic characteristics of hexahistidine-containing organophosphorus hydrolase (His6-OPH and its enzyme-polyelectrolyte complexes with poly-l-glutamic acid or poly-l-aspartic acid (His6-OPH/PLD50, hydrolyzing organophosphorous compounds, and N-acyl homoserine lactones were studied in the presence of various antibiotics (ampicillin, gentamicin, kanamycin, and rifampicin. The antibiotics at concentrations below 1 g·L−1 had a negligible inhibiting effect on the His6-OPH activity. Mixed inhibition of His6-OPH was established for higher antibiotic concentrations, and rifampicin was the most potent inhibitor. Stabilization of the His6-OPH activity was observed in the presence of antibiotics at a concentration of 0.2 g·L−1 during exposure at 25–41 °C. Molecular docking of antibiotics to the surface of His6-OPH dimer revealed the antibiotics binding both to the area near active centers of the enzyme subunits and to the region of contact between subunits of the dimer. Such interactions between antibiotics and His6-OPH were verified with Fourier-transform infrared (FTIR spectroscopy. Considering all the results of the study, the combination of His6-OPH/PLD50 with β-lactam antibiotic ampicillin was established as the optimal one in terms of exhibition and persistence of maximal lactonase activity of the enzyme.

  15. Degradation of Organophosphorus and Pyrethroid Insecticides in Beverages: Implications for Risk Assessment

    Directory of Open Access Journals (Sweden)

    Samantha A. Radford

    2018-02-01

    Full Text Available Since urinary insecticide metabolites are commonly used as biomarkers of exposure, it is important that we quantify whether insecticides degrade in food and beverages in order to better perform risk assessment. This study was designed to quantify degradation of organophosphorus and pyrethroid insecticides in beverages. Purified water, white grape juice, orange juice, and red wine were fortified with 500 ng/mL diazinon, malathion, chlorpyrifos, permethrin, cyfluthrin, cypermethrin, and deltamethrin, and aliquots were extracted several times over a 15-day storage period at 2.5 °C. Overall, statistically significant loss of at least one insecticide was observed in each matrix, and at least five out of seven insecticides demonstrated a statistically significant loss in all matrices except orange juice. An investigation of an alternative mechanism of insecticide loss—adsorption onto the glass surface of the storage jars—was carried out, which indicated that this mechanism of loss is insignificant. Results of this work suggest that insecticides degrade in these beverages, and this degradation may lead to pre-existing insecticide degradates in the beverages, suggesting that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk.

  16. Theoretical and experimental study of actinide complexes with monoamides and organophosphorus ligands in solution

    International Nuclear Information System (INIS)

    Ribokaite, Kristina

    2013-01-01

    Monoamides and organophosphate are of great interest for the nuclear fuel cycle. Such ligands can selectively extract actinides in liquid-liquid extraction processes. The structure of the extractant (its functional group and its alkyl substituents) has a predominant role in the selective separation of actinides. This thesis concerns the theoretical and experimental studies of model systems in the aim of better understanding of the effect on molecular structures of the complexes. Structures of actinides complexes formed with model ligands in simple media (water or methanol in the presence of nitrate ions) have been characterized. At first, the complexation of uranyl by monoamide and phosphine oxide was studied in water and methanol. Molecular Dynamics simulations and DFT calculations were used to quantify the stability of uranyl complexes with those ligands, and to determine their structural properties. The theoretical results were then compared with experimental results obtained by UV-visible, infrared, Raman and EXAFS on the same chemical systems. The results were used to highlight the greater stability of uranyl complexes with phosphine oxide and monoamides. Further spectroscopic measurements combined with molecular modeling were used to gain a better understanding of the coordination mode of nitrate ion around the uranyl in both water and methanol. Finally, DFT calculations were used to study the influence of the structure of the monoamide or organophosphorus ligand and their interaction with the actinides (IV, VI) including steric effects in the first coordination sphere. (author) [fr

  17. Pharmacological treatment of organophosphorus insecticide poisoning: the old and the (possible) new.

    Science.gov (United States)

    Eddleston, Michael; Chowdhury, Fazle Rabbi

    2016-03-01

    Despite being a major clinical and public health problem across the developing world, responsible for at least 5 million deaths over the last three decades, the clinical care of patients with organophosphorus (OP) insecticide poisoning has little improved over the last six decades. We are still using the same two antidotes - atropine and oximes - that first came into clinical use in the late 1950s. Clinical research in South Asia has shown how improved regimens of atropine can prevent deaths. However, we are still unsure about which patients are most likely to benefit from the use of oximes. Supplemental antidotes, such as magnesium, clonidine and sodium bicarbonate, have all been proposed and studied in small trials without production of definitive answers. Novel antidotes such as nicotinic receptor antagonists, beta-adrenergic agonists and lipid emulsions are being studied in large animal models and in pilot clinical trials. Hopefully, one or more of these affordable and already licensed antidotes will find their place in routine clinical care. However, the large number of chemically diverse OP insecticides, the varied poisoning they produce and their varied response to treatment might ultimately make it difficult to determine definitively whether these antidotes are truly effective. In addition, the toxicity of the varied solvents and surfactants formulated with the OP active ingredients complicates both treatment and studies. It is possible that the only effective way to reduce deaths from OP insecticide poisoning will be a steady reduction in their agricultural use worldwide. © 2015 The British Pharmacological Society.

  18. Cholinesterase reactivators and bioscavengers for pre- and post-exposure treatments of organophosphorus poisoning.

    Science.gov (United States)

    Masson, Patrick; Nachon, Florian

    2017-08-01

    Organophosphorus agents (OPs) irreversibly inhibit acetylcholinesterase (AChE) causing a major cholinergic syndrome. The medical counter-measures of OP poisoning have not evolved for the last 30 years with carbamates for pretreatment, pyridinium oximes-based AChE reactivators, antimuscarinic drugs and neuroprotective benzodiazepines for post-exposure treatment. These drugs ensure protection of peripheral nervous system and mitigate acute effects of OP lethal doses. However, they have significant limitations. Pyridostigmine and oximes do not protect/reactivate central AChE. Oximes poorly reactivate AChE inhibited by phosphoramidates. In addition, current neuroprotectants do not protect the central nervous system shortly after the onset of seizures when brain damage becomes irreversible. New therapeutic approaches for pre- and post-exposure treatments involve detoxification of OP molecules before they reach their molecular targets by administrating catalytic bioscavengers, among them phosphotriesterases are the most promising. Novel generation of broad spectrum reactivators are designed for crossing the blood-brain barrier and reactivate central AChE. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. © 2017 International Society for Neurochemistry.

  19. Effects of organophosphorus flame retardant TDCPP on normal human corneal epithelial cells: Implications for human health.

    Science.gov (United States)

    Xiang, Ping; Liu, Rong-Yan; Li, Chao; Gao, Peng; Cui, Xin-Yi; Ma, Lena Q

    2017-11-01

    Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is one of the most detected organophosphorus flame retardants (OPFRs) in the environment, especially in indoor dust. Continuous daily exposure to TDCPP-containing dust may adversely impact human cornea. However, its detrimental effects on human corneal epithelium are largely unknown. In this study, we investigated the cell apoptosis in normal human corneal epithelial cells (HCECs) after TDCPP exposure and elucidated the underlying molecular mechanisms. Our data indicated a dose-dependent decrease of cell viability after TDCPP exposure with LC 50 at 202 μg/mL. A concentration-dependent apoptotic sign was observed in HCECs after exposing to ≥2 μg/mL TDCPP. Endoplasmic reticulum stress induction was evidenced by up-regulation of its biomarker genes (ATF-4, CHOP, BiP, and XBP1). Furthermore, alternation of Bcl-2/Bax expression, mitochondrial membrane potential loss, cellular ATP content decrease, and caspase-3 and -9 activity increase were observed after exposing to 2 or 20 μg/mL TDCPP. Taken together, the data implicated the involvement of endoplasmic reticulum stress in TDCPP-induced HCEC apoptosis, probably mediated by mitochondrial apoptotic pathway. Our findings showed TDCPP exposure induced toxicity to human cornea. Due to TDCPP's presence at high levels in indoor dust, further study is warranted to evaluate its health risk on human corneas. Published by Elsevier Ltd.

  20. Suicidal Death due to Organophosphorus Compound Poisoning ─ an Experience of 67 Cases

    Directory of Open Access Journals (Sweden)

    Nashid Tabassum Khan

    2016-05-01

    Full Text Available Background: Bangladesh is an agro-based country. Suicide by agrochemical compounds are increasing day by day in this country. Organophosphorus compounds (OPC are commonly used for suicide. Mostly these are used for suicidal purpose in rural areas in our country due to low cost, toxicity and availability. Objective: To find out the relationship of age and sex variation along with the causes that influenced different income group people to ingest OPC for committing suicide. Materials and Methods: This study was conducted in the Department of Forensic Medicine, Dhaka Medical College during January to December 2010. Data were collected at the time of autopsy and from postmortem examination report of viscera. Viscera were preserved and sent to the Chief Chemical Examiner’s Office, Dhaka for toxicological analysis. Results: In this study, middle aged subjects (20–30 years were found to commit suicide using OPC in comparison to other age groups. Among the cases male were 57% and female 43%. Poverty was found as the most common cause (20% of OPC poisoning. Conclusion: Poverty is the leading cause of death of OPC poisoning followed by failure in love and adultery. Business failure, unhappiness in conjugal life, demand for dowry and violence against women are other causes to commit suicide by OPC.

  1. Organophosphorus pesticide exposure in agriculture: effects of temperature, ultraviolet light and abrasion on PVC gloves

    Science.gov (United States)

    ISMAIL, Ismaniza; GASKIN, Sharyn; PISANIELLO, Dino; EDWARDS, John W.

    2017-01-01

    Elbow length PVC gloves are often recommended for protection against organophosphorus pesticide (OP) exposure in agriculture. However, performance may be reduced due to high temperature, UV exposure and abrasion. We sought to assess these impacts for two OPs under normal use and reasonable worst-case scenarios. Glove permeation tests were conducted using ASTM cells with two PVC glove brands at 23°C and 45°C for up to 8 h. Technical grade dichlorvos and formulated diazinon were used undiluted and at application strength. Breakthough of undiluted dichlorvos occurred at both 23°C and 45°C, but only at 45°C for application strength. Breakthrough of diazinon was not achieved, except when undiluted at 45°C. UV-exposed and abraded gloves showed reduced performance, with the effect being approximately two-fold for dichlorvos. Only small differences were noted between glove brands. Extra precautions should be taken when handling concentrated OPs at high temperature, or when using abraded or sunlight-exposed gloves. PMID:29199264

  2. Effect of diluents on the extraction of actinides and nitric acid by bidentate organophosphorus compounds

    International Nuclear Information System (INIS)

    Rozen, A.M.

    1986-01-01

    The effect of dilutents on extraction by bidentate organophosphorus compounds (diphosphine dioxides, carbamoyl phosphonates, and phosphine oxides) was studied. Figures show the effect of dilutents on the extraction of americium by TOPO and by carbamoylmethylene phosphonate, and the effect of dilutents on the extraction of nitric acid and americium by carbamoylphosphine oxide. Also shown is the effect of dilutents on the extraction of americium by diphenyldioctyl methylenediphosphine dioxide, and the effect of dilutents on the extraction of americium by tetraphenylmethylenediphosphine dioxide. It was concluded that when TBP is added the distribution coefficient of Am increases but the effect of TBP may not be represented by the usual power relationship between the distribution coefficient and the TBP concentration, which would be expected if TBP was found to be very strong but for dilution by DCE it was relatively weak. The observed facts can be explained if it is assumed that TBP reacts with the bridging protons in the complex, which are free for dilution by benzene and are partially occupied when dichlorethane is used

  3. Computational Enzymology and Organophosphorus Degrading Enzymes: Promising Approaches Toward Remediation Technologies of Warfare Agents and Pesticides.

    Science.gov (United States)

    Ramalho, Teodorico C; de Castro, Alexandre A; Silva, Daniela R; Silva, Maria Cristina; Franca, Tanos C C; Bennion, Brian J; Kuca, Kamil

    2016-01-01

    The re-emergence of chemical weapons as a global threat in hands of terrorist groups, together with an increasing number of pesticides intoxications and environmental contaminations worldwide, has called the attention of the scientific community for the need of improvement in the technologies for detoxification of organophosphorus (OP) compounds. A compelling strategy is the use of bioremediation by enzymes that are able to hydrolyze these molecules to harmless chemical species. Several enzymes have been studied and engineered for this purpose. However, their mechanisms of action are not well understood. Theoretical investigations may help elucidate important aspects of these mechanisms and help in the development of more efficient bio-remediators. In this review, we point out the major contributions of computational methodologies applied to enzyme based detoxification of OPs. Furthermore, we highlight the use of PTE, PON, DFP, and BuChE as enzymes used in OP detoxification process and how computational tools such as molecular docking, molecular dynamics simulations and combined quantum mechanical/molecular mechanics have and will continue to contribute to this very important area of research.

  4. Toxicology of organophosphorus compounds in view of an increasing terrorist threat.

    Science.gov (United States)

    Worek, Franz; Wille, Timo; Koller, Marianne; Thiermann, Horst

    2016-09-01

    The implementation of the Chemical Weapon Convention (CWC), prohibiting the development, production, storage and use of chemical weapons by 192 nations and the ban of highly toxic OP pesticides, especially class I pesticides according to the WHO classification, by many countries constitutes a great success of the international community. However, the increased interest of terrorist groups in toxic chemicals and chemical warfare agents presents new challenges to our societies. Almost seven decades of research on organophosphorus compound (OP) toxicology was mainly focused on a small number of OP nerve agents despite the fact that a huge number of OP analogues, many of these agents having comparable toxicity to classical nerve agents, were synthesized and published. Only limited physicochemical, toxicological and medical information on nerve agent analogues is available in the open literature. This implies potential gaps of our capabilities to detect, to decontaminate and to treat patients if nerve agent analogues are disseminated and may result in inadequate effectiveness of newly developed countermeasures. In summary, our societies may face new, up to now disregarded, threats by toxic OP which calls for increased awareness and appropriate preparedness of military and civilian CBRN defense, a broader approach for new physical and medical countermeasures and an integrated system of effective detection, decontamination, physical protection and treatment.

  5. Specificity of carboxylesterase protection against the toxicity of organophosphorus compounds. (Reannouncement with new availability information)

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, D.M.

    1992-12-31

    The ability of endogenous carboxylesterase (CaE) to protect against the lethal effects of a variety of organophosphorus (OP) compounds was examined in rats. The in vivo protection provided by endogenous CaE was measured by the difference in the LD50 values of OP compounds in controlrats and rats whose CaE activity had been inhibited by sc injection with2 mg/kg of 2-(O cresyl)-4H-1,3,2-benzodi oxaphosphorin-2-oxide. Endogenous CaE provided significant protection against the in vivo toxicity of soman, sarin, tabun, and paraoxon, but not against dichlorvos, diisopropyl fluorophosphate, or ethoxymethyl-S-2- (DIISOPROPYLAMINO)ETHYL THIOPHOSPHONATE (VX). The relationship between the in vivo CaE protection against OP compounds and their relative reactivities with CaE and acetylcholinesterase (AChE) was evaluated by measuring the in vitro bimolecular rate constants (ki) for inhibition of plasma CaE and brain AChE. Except for VX, ki values for CaE inhibition varied <10-fold while ki values for AChE inhibition varied 105-fold. Chemical warfare agents, Nerve agents, Organophosphoruscompound soman, VX, Carboxylesterase, Protection, Pretreatment.

  6. [ACTIVITY OF Ca2+,Mg(2+)-ATPase OF SARCOPLASMIC RETICULUM AND CONTRACTION STRENGTH OF THE FROG SKELETAL MUSCLES UNDER THE EFFECT OF ORGANOPHOSPHORUS INSECTICIDES].

    Science.gov (United States)

    Nozdrenko, D M; Korchinska, L V; Soroca, V M

    2015-01-01

    The results of an experimental study of organophosphorus insecticides, including pirimiphosmethyl, diazinon and chlorpyrifos caused a decline of the contraction properties in m. tibialis anterior fiber bundles of Rana temporaria, as well as sarcoplasmic reticulum Ca2+, Mg(2+)-ATPase enzymatic activity reduction are outlined in this paper. Concentration-dependent strengths response diminishing in isolated skeletal muscle fiber bundles as a result of non-cholinergic influence of organophosphorus insecticides were found. A decrease of Ca2+, Mg(2+)-ATPase enzymatic activity in sarcoplasmic reticulum was observed after administration of each insecticide. The most significant inhibition of this enzyme was observed when using chlorpyrifos.

  7. Electron-beam-charged dielectrics: Internal charge distribution

    Science.gov (United States)

    Beers, B. L.; Pine, V. W.

    1981-01-01

    Theoretical calculations of an electron transport model of the charging of dielectrics due to electron bombardment are compared to measurements of internal charge distributions. The emphasis is on the distribution of Teflon. The position of the charge centroid as a function of time is not monotonic. It first moves deeper into the material and then moves back near to the surface. In most time regimes of interest, the charge distribution is not unimodal, but instead has two peaks. The location of the centroid near saturation is a function of the incident current density. While the qualitative comparison of theory and experiment are reasonable, quantitative comparison shows discrepancies of as much as a factor of two.

  8. Residual dust charges in discharge afterglow

    International Nuclear Information System (INIS)

    Coueedel, L.; Mikikian, M.; Boufendi, L.; Samarian, A. A.

    2006-01-01

    An on-ground measurement of dust-particle residual charges in the afterglow of a dusty plasma was performed in a rf discharge. An upward thermophoretic force was used to balance the gravitational force. It was found that positively charged, negatively charged, and neutral dust particles coexisted for more than 1 min after the discharge was switched off. The mean residual charge for 200-nm-radius particles was measured. The dust particle mean charge is about -5e at a pressure of 1.2 mbar and about -3e at a pressure of 0.4 mbar

  9. Effects of the organophosphorus pesticide Folisuper 600 (methyl parathion on the heart function of bullfrog tadpoles, Lithobates catesbeianus (Shaw, 1802

    Directory of Open Access Journals (Sweden)

    M. J. Costa

    Full Text Available Abstract The aim of this work was to evaluate whether the heart function of bullfrog tadpoles (25 Gosner stage is affected by their acute exposure (48 h to a sub-lethal concentration (10 µg.L–1 of the active principle of the organophosphorus pesticide Folisuper 600R (methyl parathion - MP. Our results demonstrated that MP causes not only a reduction in tadpoles’ cardiac ventricular mass, resulting in a marked reduction in their cardiac twitch force, but also impairs their swimming performance, irrespective of increasing their heart rate. Together, these findings indicate that low and realistic concentration of MP have a negative impact on tadpoles’ performance, jeopardizing their survival.

  10. Workplace Charging. Charging Up University Campuses

    Energy Technology Data Exchange (ETDEWEB)

    Giles, Carrie [ICF International, Fairfax, VA (United States); Ryder, Carrie [ICF International, Fairfax, VA (United States); Lommele, Stephen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-01

    This case study features the experiences of university partners in the U.S. Department of Energy's (DOE) Workplace Charging Challenge with the installation and management of plug-in electric vehicle (PEV) charging stations.

  11. Electrostatic charge characteristics of jet nebulized aerosols.

    Science.gov (United States)

    Kwok, Philip Chi Lip; Trietsch, Sebastiaan J; Kumon, Michiko; Chan, Hak-Kim

    2010-06-01

    Liquid droplets can be spontaneously charged in the absence of applied electric fields by spraying. It has been shown by computational simulation that charges may influence particle deposition in the airways. The electrostatic properties of jet nebulized aerosols and their potential effects on lung deposition have hardly been studied. A modified electrical low pressure impactor (ELPI) was employed to characterize the aerosol charges generated from jet nebulized commercial products. The charge and size measurements were conducted at 50% RH and 22 degrees C with a modified ELPI. Ventolin, Bricanyl, and Atrovent were nebulized using PARI LC Plus jet nebulizers coupled to a DeVilbiss Pulmo-Aide compressor. The aerosols were sampled in 30-sec durations. The drug deposits on the impactor stages were assayed chemically using high-performance liquid chromatography (HPLC). The charges of nebulized deionized water, isotonic saline, and the three commercial products diluted with saline were also measured to analyze the contributions of the major nebule ingredients on charging. No mass assays were performed on these runs. All three commercial nebules generated net negative charges. The magnitude of the charges reduced over the period of nebulization. Ventolin and Bricanyl yielded similar charge profiles. Highly variable charges were produced from deionized water. On the other hand, nebulized saline reproducibly generated net positive charges. Diluted commercial nebules showed charge polarity inversion. The charge profiles of diluted salbutamol and terbutaline solutions resembled those of saline, while the charges from diluted ipratropium solutions fluctuated near neutrality. The charge profiles were shown to be influenced by the concentration and physicochemical properties of the drugs, as well as the history of nebulization. The drugs may have unique isoelectric concentrations in saline at which the nebulized droplets would carry near-zero charges. According to results from

  12. Quick spacecraft charging primer

    International Nuclear Information System (INIS)

    Larsen, Brian Arthur

    2014-01-01

    This is a presentation in PDF format which is a quick spacecraft charging primer, meant to be used for program training. It goes into detail about charging physics, RBSP examples, and how to identify charging.

  13. Phytase production by Aspergillus niger NCIM 563 for a novel application to degrade organophosphorus pesticides.

    Science.gov (United States)

    Shah, Parin C; Kumar, V Ravi; Dastager, Syed G; Khire, Jayant M

    2017-12-01

    The production of phytase using Aspergillus niger NCIM 563 under submerged fermentation conditions was studied using protein rich chickpea flour as substrate. Employing a hybrid statistical media optimization strategy of Plackett-Burman and Box-Behnken experimental designs in shake-flasks gave an increased phytase activity from an initial 66 IU/mL in 216 h to 160 IU/mL in a reduced time of 132 h. Productivity, thus increased by 3.97 times from 7.3 to 29 IU/mL/day. Using the optimized media, the production was successfully scaled-up further and improved up to 164 IU/mL in 96 h by studies carried out employing 2 and 10-L fermenters. The enzyme supernatant was recovered using centrifugal separation of biomass and the stability of the produced phytase was tested for animal feed applications under gastric conditions. In vitro degradation studies of water soluble monocrotophos, methyl parathion and water insoluble chlorpyrifos, pesticides used extensively in agriculture was carried out. It was observed by HPLC analysis that phytase could degrade 72% of chlorpyrifos at pH 7.0, 35 °C. Comparable results were obtained with monocrotophos and methyl parathion. With chlorpyrifos at higher temperature 50 °C as much as 91% degradation could be obtained. The degradation of chlorpyrifos was further validated by spraying phytase on harvested green chilli (Capsicum annuum L) under normal conditions of pH 7.0, 35 °C and the degradation products obtained analyzed by LCMS. Thus, the present study brings out a potentially novel application of phytase for biodegradation of organophosphorus pesticides.

  14. Determination of Organophosphorus Pesticides in Soil by Dispersive Liquid–Liquid Microextraction and Gas Chromatography

    Science.gov (United States)

    Yang, Zhonghua; Liu, Yu; Liu, Donghui; Zhou, Zhiqiang

    2012-01-01

    In this article, a rapid and sensitive sample pretreatment technique for the determination of organophosphorus pesticides (OPPs) in soil samples is developed by using dispersive liquid–liquid microextraction (DLLME) combined with gas chromatography–flame photometric detection. Experimental conditions, including the kind of extraction and disperser solvent and their volumes, the extraction time, and the salt addition, are investigated, and the following experiment factors are used: 20 µL chlorobenzene as the extraction solvent; 1.0 mL acetonitrile as the disperser solvent; no addition of salt; and an extraction time of 1 min. Under the optimum conditions, the linearities for the three target OPPs (ethoprophos, chlorpyriphos, and profenofos) are obtained by five points in the concentration range of 2.5–1500 µg/kg, and three replicates are used for each point. Correlation coefficients vary from 0.9987 to 0.9997. The repeatability is tested by spiking soil samples at a concentration level of 5.0 µg/kg. The relative standard deviation (n = 3) varied between 2.0% and 6.6%. The limits of detection, based on a signal-to-noise ratio (S/N) of 3, range from 200 to 500 pg/g. This method is applied to the analysis of the spiked samples S1, S2, and S3, which are collected from the China Agriculture University's orchard, lawn, and garden, respectively. The recoveries for each target analyte are in the range between 87.9% and 108.0%, 87.4% and 108.0%, and 86.7% and 107.2%, respectively. PMID:22291051

  15. Zirconium(IV) functionalized magnetic nanocomposites for extraction of organophosphorus pesticides from environmental water samples.

    Science.gov (United States)

    Jiang, Li; Huang, Tengjun; Feng, Shun; Wang, Jide

    2016-07-22

    The widespread use of organophosphate pesticides (OPPs) in agriculture leads to residue accumulation in the environment which is dangerous to human health and disrupts the ecological balance. In this work, one nanocomposite immobilized zirconium (Zr, IV) was prepared and used as the affinity probes to quickly and selectively extract organophosphorus pesticides (OPPs) from water samples. The Fe3O4-ethylenediamine tetraacetic acid (EDTA)@Zr(IV) nanocomposites (NPs) were prepared by simply mixing Zr(IV) ions with Fe3O4-EDTA NPs synthesized by one-pot chemical co-precipitation method. The immobilized Zr(IV) ions were further utilized to capture OPPs based on their high affinity for the phosphate moiety in OPPs. Coupled with GC-MS, four OPPs were used as models to demonstrate the feasibility of this approach. Under the optimum conditions, the limits of detection for target OPPs were in the range of 0.10-10.30ngmL(-1) with relative standard deviations (RSDs) of 0.61-4.40% (n=3), respectively. The linear ranges were over three orders of magnitudes (correlation coefficients, R(2)>0.9995). The Fe3O4-EDTA@Zr(IV) NPs were successfully applied to extract OPPs samples with recoveries of 86.95-112.60% and RSDs of 1.20-10.42% (n=3) from two spiked real water. By the proposed method, the matrix interference could be effectively eliminated. We hope our finding can provide a promising alternative for the fast extraction of OPPs from complex real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Spatial learning impairment in prepubertal guinea pigs prenatally exposed to the organophosphorus pesticide chlorpyrifos: Toxicological implications

    Science.gov (United States)

    Mamczarz, Jacek; Pescrille, Joseph D.; Gavrushenko, Lisa; Burke, Richard D.; Fawcett, William P.; DeTolla, Louis J.; Chen, Hegang; Pereira, Edna F.R.; Albuquerque, Edson X.

    2017-01-01

    Exposure of the developing brain to chlorpyrifos (CPF), an organophosphorus (OP) pesticide used extensively in agriculture worldwide, has been associated with increased prevalence of cognitive deficits in children, particularly boys. The present study was designed to test the hypothesis that cognitive deficits induced by prenatal exposure to sub-acute doses of CPF can be reproduced in precocial small species. To address this hypothesis, pregnant guinea pigs were injected daily with CPF (25 mg/kg, s.c.) or vehicle (peanut oil) for 10 days starting on presumed gestation day (GD) 53–55. Offspring were born around GD 65, weaned on postnatal day (PND) 20, and subjected to behavioral tests starting around PND 30. On the day of birth, butyrylcholinesterase (BuChE), an OP bioscavenger used as a biomarker of OP exposures, and acetylcholinesterase (AChE), a major molecular target of OP compounds, were significantly inhibited in the blood of CPF-exposed offspring. In their brains, BuChE, but not AChE, was significantly inhibited. Prenatal CPF exposure had no significant effect on locomotor activity or on locomotor habituation, a form of non-associative memory assessed in open fields. Spatial navigation in the Morris water maze (MWM) was found to be sexually dimorphic among guinea pigs, with males outperforming females. Prenatal CPF exposure impaired spatial learning more significantly among male than female guinea pigs and, consequently, reduced the sexual dimorphism of the task. The results presented here, which strongly support the test hypothesis, reveal that the guinea pig is a valuable animal model for preclinical assessment of the developmental neurotoxicity of OP pesticides. These findings are far reaching as they lay the groundwork for future studies aimed at identifying therapeutic interventions to treat and/or prevent the neurotoxic effects of CPF in the developing brain. PMID:27296654

  17. Effect of organophosphorus insecticides and their metabolites on astroglial cell proliferation

    International Nuclear Information System (INIS)

    Guizzetti, Marina; Pathak, Shantha; Giordano, Gennaro; Costa, Lucio G.

    2005-01-01

    Though little attention has been given to the possibility that glial cells may represent a target for the developmental neurotoxicity of organophosphorus (OP) insecticides, recent evidence, obtained in particular with chlorpyrifos (CP), suggests that developmental exposure to this compound may indeed target astrocytes. To substantiate and expand these observations, we carried out a series of in vitro studies utilizing fetal rat astrocytes and a human astrocytoma cell line, 1321N1 cells, to investigate the effect of the OPs CP, diazinon (DZ) and parathion (P), their oxygen analogs chlorpyrifos oxon (CPO), diazoxon (DZO) and paraoxon (PO), and their metabolites 3,5,6-trichloro-2-pyridinol (TCP), 2-isopropyl-6-methyl-4-pyrimidol (IMP) and para-nitrophenol (PNP), on cell proliferation. In fetal rat astrocytes and astrocytoma cells maintained in serum, CP, DZ, P, CPO, DZO, and PO induced a concentration-dependent inhibition in [ 3 H]thymidine incorporation with a very similar potency (IC 50 between 45 and 57 μM). Among the other metabolites, PNP was the most potent (IC 50 = 70-80 μM), while TCP and IMP were much less effective (IC 50 > 100 μM). Cytotoxicity appears to account only for a small part of the effect on DNA synthesis. OP insecticides and their oxons were three- to six-fold more potent in inhibiting [ 3 H]thymidine incorporation when cells were synchronized in the G 0 /G 1 phase of the cell cycle and re-stimulated by carbachol or epidermal growth factor. These results suggest that OP insecticides and their oxons affect astroglial cell proliferation and that the transition from the G 0 /G 1 to the S/G 2 phase of the cell cycle may be particularly sensitive to the action of these compounds

  18. Modulatory Effect Of Olive Oil On Toxicity Induced By Organophosphorus Pesticides In Male Rat

    International Nuclear Information System (INIS)

    AFIFI, E.A.A.; ALI, S.E.

    2009-01-01

    The present study was carried out to investigate the modulatory effect of olive oil (5 ml/kg b.wt.) against the toxicological effects of repeated daily oral administration of the organophosphorus pesticides malaphos (137.5 mg/kg), mephosfolan (0.89 mg/kg) and phosfolan (1.0 mg/kg) for one, two and four weeks on certain biochemical parameters such as serum albumin, globulin and A/G ratio, low density lipoprotein-cholesterol (LDL-cholesterol), high density lipoprotein-cholesterol (HDL-cholesterol), total cholesterol, total protein, gamma glutamyl transferase ( GT) and plasma triglycerides. In addition, modulation of blood urea, creatinine and uric acid were observed through all the experimental intervals. Also, the serum concentration of triiodothyronine (T 3 ), thyroxine (T 4 ) and thyroid stimulating hormone (TSH) were determined.The data obtained revealed significant decrease in serum total protein, albumin, globulin and HDL-cholesterol while significant increase in serum albumin to globulin ratio (A/G), triglycerides, creatinine, urea, uric acid, LDL-cholesterol, total cholesterol and GT in all treated groups was observed. On the other hand, the data recorded imbalance in thyroid function as a result of pesticides treatments, which donated that each of the three pesticides increased TSH secretion, while malaphos caused significant decrease in both T 3 and T 4 levels, mephosfolan increased T 4 and decreased T 3 levels, whereas phosfolan pesticide decreased T 4 and increased T 3 levels after one, two and four weeks post-treatment.Administration of olive oil during treatment with malaphos, mephosfolan and phosfolan pesticides attenuates to a great extent the destructive effects of pesticides on the assayed parameters, this effect is attributed to the beneficial properties whom olive oil possess as anti-oxidative potential that may act to protect the body organs against the pesticides toxicity and also due to the amelioration of oxidative stress of free radicals.

  19. Organophosphorus pesticides decrease M2 muscarinic receptor function in guinea pig airway nerves via indirect mechanisms.

    Directory of Open Access Journals (Sweden)

    Becky J Proskocil

    Full Text Available BACKGROUND: Epidemiological studies link organophosphorus pesticide (OP exposures to asthma, and we have shown that the OPs chlorpyrifos, diazinon and parathion cause airway hyperreactivity in guinea pigs 24 hr after a single subcutaneous injection. OP-induced airway hyperreactivity involves M2 muscarinic receptor dysfunction on airway nerves independent of acetylcholinesterase (AChE inhibition, but how OPs inhibit neuronal M2 receptors in airways is not known. In the central nervous system, OPs interact directly with neurons to alter muscarinic receptor function or expression; therefore, in this study we tested whether the OP parathion or its oxon metabolite, paraoxon, might decrease M2 receptor function on peripheral neurons via similar direct mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Intravenous administration of paraoxon, but not parathion, caused acute frequency-dependent potentiation of vagally-induced bronchoconstriction and increased electrical field stimulation (EFS-induced contractions in isolated trachea independent of AChE inhibition. However, paraoxon had no effect on vagally-induced bradycardia in intact guinea pigs or EFS-induced contractions in isolated ileum, suggesting mechanisms other than pharmacologic antagonism of M2 receptors. Paraoxon did not alter M2 receptor expression in cultured cells at the mRNA or protein level as determined by quantitative RT-PCR and radio-ligand binding assays, respectively. Additionally, a biotin-labeled fluorophosphonate, which was used as a probe to identify molecular targets phosphorylated by OPs, did not phosphorylate proteins in guinea pig cardiac membranes that were recognized by M2 receptor antibodies. CONCLUSIONS/SIGNIFICANCE: These data indicate that neither direct pharmacologic antagonism nor downregulated expression of M2 receptors contributes to OP inhibition of M2 function in airway nerves, adding to the growing evidence of non-cholinergic mechanisms of OP neurotoxicity.

  20. Evaluation of the organophosphorus hydrolase enzyme activity in creams and investigation of its stability

    Directory of Open Access Journals (Sweden)

    Mariye Rajaie

    2016-06-01

    Full Text Available The main purpose of this project is investigation of the organophosphorus hydrolase (OPH enzyme activity in water in oil (w/o and oil in water (o/w creams and investigation of the OPH enzyme stability in formulated creams. OPH enzyme was extracted and purified from strain flavobacterium. The w/o and o/w creams were prepared using different formulations. In order to achieve an emulsion with maximum stability, appropriate percentage of the cream components was selected by studying different formulations and the physical and chemical stability of the produced cream were considered. 5Uenzyme/90gcream enzyme was used for each formulation. To measure the enzyme activity in creams, extraction method was used and enzyme activity was determined based on parathion hydrolysis. The thermal stability of OPH in both types of w/o and o/w creams was studied at 4 and 30  °C for various time periods. The average enzyme activity was about 0.0065 U/gcream and 0.018 U/gcream for w/o and o/w creams respectivly. According to the results, the relative activity at 4 °C was reduced to 50% after 26 and 45 days in w/o and o/w creams, respectivly. The results showed that the OPH enzyme activity in o/w cream was 2.6 times more than that of w/o cream, because of the higher hydrophobicity of o/w cream compared to w/o. The OPH enzyme stability in o/w cream was greater in comparison to w/o cream. The OPH enzyme was active for nearly 2 months on o/w creams at 4 °C .

  1. Dialkyl phosphate metabolites of organophosphorus in applicators of agricultural pesticides in Majes – Arequipa (Peru

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    Chung Arturo

    2006-12-01

    Full Text Available Abstract Background Organophosphorus (OPs pesticides are the most commonly used pesticides in Peruvian agriculture. The population at risk for OPs exposure includes formulators, applicators and farmers. Majes Valley is the most important agricultural center of the Southern region of Peru. The present study was aimed to determine the knowledge about using OPs, safety practice and urinary dialkylphosphate metabolites on OP applicators in the Majes Valley, Peru. Methods This study was based on a questionnaire which included socio-demographic characteristics, knowledge of safety practices to handling OPs, characteristics of pesticide application and use of protective measures to avoid pesticide contamination. Exposure was assessed by measuring six urinary OP metabolites (DMP, DMTP, DMDTP, DEP, DETP, and DEDTP by gas chromatography using a single flame photometric detector. The sample consisted of 31 men and 2 women aged 20 – 65 years old. Results 76% of applicators had at least one urinary dialkylphosphate metabolite above the limit of detection. The geometric mean (GM and the geometric standard deviation (GSD of DMP and DEP were 5.73 ug/g cr. (GSD 2.51, and 6.08 ug/g cr. (GSD 3.63, respectively. The percentage of applicators with detectable DMP, DMDTP, and DMTP in urine was 72.72%, 3.03%, and 15.15%, respectively, while the corresponding figures for DEP, DETP, and DEDTP were 48.48%, 36.36% and 15.15%, respectively. There was no significant association between the use of protection practices and the absence of urine OPs metabolites suggesting inadequate protection practices. Conclusion The pesticide applicators in Majes Valley have significant exposure to OP pesticides, probably due to inappropriate protective practices. Future work should evaluate possible health effects.

  2. Organophosphorus pollutants (OPP) in aquatic environment at Damietta Governorate, Egypt: implications for monitoring and biomarker responses.

    Science.gov (United States)

    Abdel-Halim, K Y; Salama, A K; El-Khateeb, E N; Bakry, N M

    2006-06-01

    The study was carried out from spring 1999 to spring 2001 to monitor the residue levels of organophosphorus pollutants (OPP) in aquatic environment of the drainage canal surrounding a pesticide factory at Damietta Governorate. Water, sediment, and fish samples were collected at six different seasonal periods. OPPs were analyzed by GLC and confirmed using GC-MS. Chlorpyrifos, chlorpyrifos-methyl, malathion, diazinon, pirimiphos-methyl and profenofos were detected in most samples. Chlorpyrifos was dominant in all water and sediment samples. It was ranged from 24.5 to 303.8 and 0.9 to 303.8 ppb in water and sediment samples, respectively. Diazinon level was slightly similar to chlorpyrifos in fish samples. Data based on the grand total concentration of OPP showed that the most polluted samples were collected either at spring 1999 or autumn 2000. They were 675.5 and 303.8 ppb in water samples and 43.0 and 52.2 ppb in fish collected at spring 1999 and autumn 2000, respectively. The obtained results are in parallel to that found in case of cholinesterase activity where the activity of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was declined at these seasonal period. The activity levels of AChE and BuChE were found to be 77.18% and 59.67% of control at spring 1999 and 78.62% and 85.80% of control, at autumn 2000, respectively. Thus, AChE and BuChE could be used as biomarkers for tracing and biomonitoring OPP pollution.

  3. Antioxidant Role of Pomegranates on Liver and Brain Tissues of Rats Exposed to an Organophosphorus Insecticide

    International Nuclear Information System (INIS)

    Abd Elmonem, H.A.

    2014-01-01

    Toxicities of organophosphorus insecticides cause oxidative damage on many organs such as the liver and brain due to generation of reactive oxygen species. Pomegranate is among the richest fruit in poly - phenols. The aim of this study was to compare between the antioxidant strength of pomegranate juice (PJ) and pomegranate molasses (PM) and their effects on alanine transferase (ALT), aspartate aminotransferase (AST), Alkaline phosphatase (ALP) and total protein (TP) in liver and levels of malondialdehyde (MAD), reduced glutathione (GSH) and nitric oxide (NO) in rat liver and brain tissues exposed to 1/10 LD 50 diazinon (DI). Six groups each of 6 male albino rats were used comprising control, DI, PJ, PM, PJ + DI and PM + DI for 15 days. The activities of ALT, AST, and TP concentration in liver have been increased due to treatment of rats with DI. These increases restored to normalcy when rats were supplemented with PJ or PM with DI. The results demonstrate that treatment with DI induced significant increase in MDA and NO concentrations and significant decrease in GSH levels of liver and brain tissues. The administration of PJ or PM along with DI significant decrease in MDA and NO levels and significant increase in GSH level compared to DI-group. The present study suggest that PJ or PM has a potential protective effect as it can elevate antioxidant defense system, lessens induced oxidative dam - ages and protect the brain and liver tissue against DI-induced toxicity. In addition, comaring PJ with PM it was noticed that PJ had higher antioxidant activity as evidenced by increased GSH content and decreased NO level in the liver by greater extend than PM.

  4. Evaluation of medical countermeasures against organophosphorus compounds: the value of experimental data and computer simulations.

    Science.gov (United States)

    Worek, Franz; Aurbek, Nadine; Herkert, Nadja M; John, Harald; Eddleston, Michael; Eyer, Peter; Thiermann, Horst

    2010-09-06

    Despite extensive research for more than six decades on medical countermeasures against poisoning by organophosphorus compounds (OP) the treatment options are meagre. The presently established acetylcholinesterase (AChE) reactivators (oximes), e.g. obidoxime and pralidoxime, are insufficient against a number of nerve agents and there is ongoing debate on the benefit of oxime treatment in human OP pesticide poisoning. Up to now, the therapeutic efficacy of oximes was mostly evaluated in animal models but substantial species differences prevent direct extrapolation of animal data to humans. Hence, it was considered essential to establish relevant experimental in vitro models for the investigation of oximes as antidotes and to develop computer models for the simulation of oxime efficacy in different scenarios of OP poisoning. Kinetic studies on the various interactions between erythrocyte AChE from various species, structurally different OP and different oximes provided a basis for the initial assessment of the ability of oximes to reactivate inhibited AChE. In the present study, in vitro enzyme-kinetic and pharmacokinetic data from a minipig model of dimethoate poisoning and oxime treatment were used to calculate dynamic changes of AChE activities. It could be shown that there is a close agreement between calculated and in vivo AChE activities. Moreover, computer simulations provided insight into the potential and limitations of oxime treatment. In the end, such data may be a versatile tool for the ongoing discussion of the pros and cons of oxime treatment in human OP pesticide poisoning. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  5. Developmental neurotoxicity of the organophosphorus insecticide chlorpyrifos: from clinical findings to preclinical models and potential mechanisms.

    Science.gov (United States)

    Burke, Richard D; Todd, Spencer W; Lumsden, Eric; Mullins, Roger J; Mamczarz, Jacek; Fawcett, William P; Gullapalli, Rao P; Randall, William R; Pereira, Edna F R; Albuquerque, Edson X

    2017-08-01

    Organophosphorus (OP) insecticides are pest-control agents heavily used worldwide. Unfortunately, they are also well known for the toxic effects that they can trigger in humans. Clinical manifestations of an acute exposure of humans to OP insecticides include a well-defined cholinergic crisis that develops as a result of the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that hydrolyzes the neurotransmitter acetylcholine (ACh). Prolonged exposures to levels of OP insecticides that are insufficient to trigger signs of acute intoxication, which are hereafter referred to as subacute exposures, have also been associated with neurological deficits. In particular, epidemiological studies have reported statistically significant correlations between prenatal subacute exposures to OP insecticides, including chlorpyrifos, and neurological deficits that range from cognitive impairments to tremors in childhood. The primary objectives of this article are: (i) to address the short- and long-term neurological issues that have been associated with acute and subacute exposures of humans to OP insecticides, especially early in life (ii) to discuss the translational relevance of animal models of developmental exposure to OP insecticides, and (iii) to review mechanisms that are likely to contribute to the developmental neurotoxicity of OP insecticides. Most of the discussion will be focused on chlorpyrifos, the top-selling OP insecticide in the United States and throughout the world. These points are critical for the identification and development of safe and effective interventions to counter and/or prevent the neurotoxic effects of these chemicals in the developing brain. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. © 2017 International Society for Neurochemistry.

  6. Rapid gas chromatography with flame photometric detection of multiple organophosphorus pesticides in Salvia miltiorrhizae after ultrasonication assisted one-step extraction.

    Science.gov (United States)

    Zhang, Shanshan; Liu, Xiaofei; Qin, Jia'an; Yang, Meihua; Zhao, Hongzheng; Wang, Yong; Guo, Weiying; Ma, Zhijie; Kong, Weijun

    2017-11-15

    A simple and rapid gas chromatography-flame photometric detection (GC-FPD) method was developed for the determination of 12 organophosphorus pesticides (OPPs) in Salvia miltiorrhizae by using ultrasonication assisted one-step extraction (USAE) without any clean-up steps. Some crucial parameters such as type of extraction solvent were optimized to improve the method performance for trace analysis. Any clean-up steps were negligent as no interferences were detected in the GC-FPD chromatograms for sensitive detection. Under the optimized conditions, limits of detection (LODs) and quantitation (LOQs) for all pesticides were in the range of 0.001-0.002mg/kg and 0.002-0.01mg/kg and 0.002-0.01mg/kg, respectively, which were all below the regulatory maximum residue limits suggested. RSDs for method precision (intra- and inter-day variations) were lower than 6.8% in approval with international regulations. Average recovery rates for all pesticides at three fortification levels (0.5, 1.0 and 5.0mg/kg) were in the range of 71.2-101.0% with relative standard deviations (RSDs) pesticide (dimethoate) out of the 12 targets was simultaneously detected in four samples at concentrations of 0.016-0.02mg/kg. Dichlorvos and omethoate were found in the same sample from Sichuan province at 0.004 and 0.027mg/kg, respectively. Malathion and monocrotophos were determined in the other two samples at 0.014 and 0.028mg/kg, respectively. All the positive samples were confirmed by LC-MS/MS. The simple, reliable and rapid USAE-GC-FPD method with many advantages over traditional techniques would be preferred for trace analysis of multiple pesticides in more complex matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Dust Measurement of Two Organophosphorus Flame Retardants, Resorcinol Bis(diphenylphosphate) (RBDPP) and Bisphenol A Bis(diphenylphosphate) (BPA-BDPP), Used as Alternatives for BDE-209

    NARCIS (Netherlands)

    Brandsma, S.H.; Sellström, U.; de Wit, C.A.; de Boer, J.; Leonards, P.E.G.

    2013-01-01

    Resorcinol bis(diphenylphosphate) (RBDPP) and bisphenol A bis(diphenylphosphate) (BPA-BDPP) are two halogen-free organophosphorus flame retardant (PFRs) that are used as an alternative for the decabromodiphenyl ether (Deca-BDE) technical mixture in TV/flatscreen housing and other electronic consumer

  8. Monitoring of organochlorine and organophosphorus pesticide residues in water during different seasons of Tighra reservoir Gwalior, Madhya Pradesh, India.

    Science.gov (United States)

    Mamta; Rao, R J; Wani, Khursheed Ahmad

    2015-11-01

    Analysis of pesticides during different seasons for pesticidal contamination in water samples of Tighra reservoir was carried out on gas chromatograph-electron capture detector with capillary columns following multiresidual analytical technique. Organochlorine pesticides, viz., hexachlorobenzene (HCB), alpha-benzene hexachloride (BHC), beta-BHC, γ-BHC, heptachlor, aldrin, alpha-endosulfan, beta-endosulfan, p,p-DDE, dieldrin, o,p-dichlorodiphenyldichloroethane (DDD), p,p-DDD, p,p-dichlorodiphenyltrichloroethane (DDT), and endrin, and organophosphorus pesticides, viz., choloropyrifos, methyl parathion, diazion, dicholorovos, ethion, malathion, and parathion, were detected in water samples during different seasons. However, the pesticide concentration varied during different seasons at different sites. The prominent reason of contamination is the use of pesticides (both organochlorine and organophosphorus) in the agricultural fields near Tighra reservoir. On the basis of our observations, more extensive monitoring studies need to be carried out, covering all wetlands of Madhya Pradesh to enforce the policies for the restricted application of pesticides in agricultural fields adjacent to wetlands.

  9. Pharmacokinetics and effects on serum cholinesterase activities of organophosphorus pesticides acephate and chlorpyrifos in chimeric mice transplanted with human hepatocytes.

    Science.gov (United States)

    Suemizu, Hiroshi; Sota, Shigeto; Kuronuma, Miyuki; Shimizu, Makiko; Yamazaki, Hiroshi

    2014-11-01

    Organophosphorus pesticides acephate and chlorpyrifos in foods have potential to impact human health. The aim of the current study was to investigate the pharmacokinetics of acephate and chlorpyrifos orally administered at lowest-observed-adverse-effect-level doses in chimeric mice transplanted with human hepatocytes. Absorbed acephate and its metabolite methamidophos were detected in serum from wild type mice and chimeric mice orally administered 150mg/kg. Approximately 70% inhibition of cholinesterase was evident in plasma of chimeric mice with humanized liver (which have higher serum cholinesterase activities than wild type mice) 1day after oral administrations of acephate. Adjusted animal biomonitoring equivalents from chimeric mice studies were scaled to human biomonitoring equivalents using known species allometric scaling factors and in vitro metabolic clearance data with a simple physiologically based pharmacokinetic (PBPK) model. Estimated plasma concentrations of acephate and chlorpyrifos in humans were consistent with reported concentrations. Acephate cleared similarly in humans and chimeric mice but accidental/incidental overdose levels of chlorpyrifos cleared (dependent on liver metabolism) more slowly from plasma in humans than it did in mice. The data presented here illustrate how chimeric mice transplanted with human hepatocytes in combination with a simple PBPK model can assist evaluations of toxicological potential of organophosphorus pesticides. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Novel organophosphorus scaffolds of urease inhibitors obtained by substitution of Morita-Baylis-Hillman adducts with phosphorus nucleophiles.

    Science.gov (United States)

    Ntatsopoulos, Vassilis; Vassiliou, Stamatia; Macegoniuk, Katarzyna; Berlicki, Łukasz; Mucha, Artur

    2017-06-16

    The reactivity of Morita-Baylis-Hillman allyl acetates was employed to introduce phosphorus-containing functionalities to the side chain of the cinnamic acid conjugated system by nucleophilic displacement. The proximity of two acidic groups, the carboxylate and phosphonate/phosphinate groups, was necessary to form interactions in the active site of urease by recently described inhibitor frameworks. Several organophosphorus scaffolds were obtained and screened for inhibition of the bacterial urease, an enzyme that is essential for survival of urinary and gastrointestinal tract pathogens. α-Substituted phosphonomethyl- and 2-phosphonoethyl-cinnamate appeared to be the most potent and were further optimized. As a result, one of the most potent organophosphorus inhibitors of urease, α-phosphonomethyl-p-methylcinnamic acid, was identified, with K i  = 0.6 μM for Sporosarcina pasteurii urease. High complementarity to the enzyme active site was achieved with this structure, as any further modifications significantly decreased its affinity. Finally, this work describes the challenges faced in developing ligands for urease. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Synthesis of organophosphorus modified nanoparticles and their reinforcements on the fire safety and mechanical properties of polyurea

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Xiaodong [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Song, Lei, E-mail: leisong@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Wang, Bibo [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Yuen, Richard K.K., E-mail: Richard.Yuen@cityu.edu.hk [USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue Kowloon (Hong Kong)

    2013-05-15

    Novel organophosphorus modified nanoparticles (FRs-nanoparticles) were synthesized by the hydrolysis and condensation of both 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified vinyl trimethoxy silane (DOPO-VTS) and 3-triethoxysilylpropylamine. FRs-nanoparticles were incorporated into the polyurea matrix in different ratios via in situ polymerization, resulting in the formation of organic/inorganic nanocomposites. The nanocomposites were characterized by thermogravimetric analysis (TGA), real-time fourier transform infrared spectra (RTIR), microscale combustion calorimeter (MCC) and tensile testing machine. The TGA results revealed that FRs-nanoparticles could slightly catalyze the thermal degradation of the nanocomposites in nitrogen atmosphere, but significantly improve the thermal stability of the nanocomposites in air atmosphere. The T{sub 0.5} (50wt.% weight loss) of the nanocomposites was delayed by 32 °C in air atmosphere. Moreover, the char yield increased from 2.3wt.% to 8.9 wt.% at 550 °C when the loadings of FRs-nanoparticles was 10wt.%, indicating the catalyzing charring effect of FRs-nanoparticles. The MCC results revealed that all the nanocomposites exhibited much lower flammability compared with virgin polyurea. Furthermore, the tensile test indicated that the FRs-nanoparticles could also improve the mechanical properties of polyurea. - Highlights: ► Novel organophosphorus modified nanoparticles (FRs-nanoparticles) were synthesized. ► FRs-nanoparticles were incorporated into the polyurea. ► Both the thermal stability and mechanical properties of polyurea were improved.

  12. Detection of Organophosphorus Pesticides in Wheat by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with HPLC

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2018-01-01

    Full Text Available Food safety issues closely related to human health have always received widespread attention from the world society. As a basic food source, wheat is the fundamental support of human survival; therefore, the detection of pesticide residues in wheat is very necessary. In this work, the ultrasonic-assisted ionic liquid-dispersive liquid-liquid microextraction (DLLME method was firstly proposed, and the extraction and analysis of three organophosphorus pesticides were carried out by combining high-performance liquid chromatography (HPLC. The extraction efficiencies of three ionic liquids with bis(trifluoromethylsulfonylimide (Tf2N anion were compared by extracting organophosphorus in wheat samples. It was found that the use of 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([OMIM][Tf2N] had both high enrichment efficiency and appropriate extraction recovery. Finally, the method was used for the determination of three wheat samples, and the recoveries of them were 74.8–112.5%, 71.8–104.5%, and 83.8–115.5%, respectively. The results show that the method proposed is simple, fast, and efficient, which can be applied to the extraction of organic matters in wheat samples.

  13. Synthesis of organophosphorus modified nanoparticles and their reinforcements on the fire safety and mechanical properties of polyurea

    International Nuclear Information System (INIS)

    Qian, Xiaodong; Song, Lei; Wang, Bibo; Hu, Yuan; Yuen, Richard K.K.

    2013-01-01

    Novel organophosphorus modified nanoparticles (FRs-nanoparticles) were synthesized by the hydrolysis and condensation of both 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified vinyl trimethoxy silane (DOPO-VTS) and 3-triethoxysilylpropylamine. FRs-nanoparticles were incorporated into the polyurea matrix in different ratios via in situ polymerization, resulting in the formation of organic/inorganic nanocomposites. The nanocomposites were characterized by thermogravimetric analysis (TGA), real-time fourier transform infrared spectra (RTIR), microscale combustion calorimeter (MCC) and tensile testing machine. The TGA results revealed that FRs-nanoparticles could slightly catalyze the thermal degradation of the nanocomposites in nitrogen atmosphere, but significantly improve the thermal stability of the nanocomposites in air atmosphere. The T 0.5 (50wt.% weight loss) of the nanocomposites was delayed by 32 °C in air atmosphere. Moreover, the char yield increased from 2.3wt.% to 8.9 wt.% at 550 °C when the loadings of FRs-nanoparticles was 10wt.%, indicating the catalyzing charring effect of FRs-nanoparticles. The MCC results revealed that all the nanocomposites exhibited much lower flammability compared with virgin polyurea. Furthermore, the tensile test indicated that the FRs-nanoparticles could also improve the mechanical properties of polyurea. - Highlights: ► Novel organophosphorus modified nanoparticles (FRs-nanoparticles) were synthesized. ► FRs-nanoparticles were incorporated into the polyurea. ► Both the thermal stability and mechanical properties of polyurea were improved

  14. Lexan Linear Shaped Charge Holder with Magnets and Backing Plate

    Science.gov (United States)

    Maples, Matthew W.; Dutton, Maureen L.; Hacker, Scott C.; Dean, Richard J.; Kidd, Nicholas; Long, Chris; Hicks, Robert C.

    2013-01-01

    A method was developed for cutting a fabric structural member in an inflatable module, without damaging the internal structure of the module, using linear shaped charge. Lexan and magnets are used in a charge holder to precisely position the linear shaped charge over the desired cut area. Two types of charge holders have been designed, each with its own backing plate. One holder cuts fabric straps in the vertical configuration, and the other charge holder cuts fabric straps in the horizontal configuration.

  15. Fluctuation charge effects in ionization fronts

    International Nuclear Information System (INIS)

    Arrayas, Manuel; Trueba, Jose L; Baltanas, J P

    2008-01-01

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster

  16. Fluctuation charge effects in ionization fronts

    Energy Technology Data Exchange (ETDEWEB)

    Arrayas, Manuel; Trueba, Jose L [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain); Baltanas, J P [Departamento de Fisica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-05-21

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster.

  17. Charging machine for a fast production reactor

    International Nuclear Information System (INIS)

    Artem'ev, L.N.; Kurilkin, V.V.

    1971-01-01

    Charging machine for a fast production reactor is described. The machine contains charging mechanism, mechanism for positioning fresh fuel and spent fuel assemtlies, storage drums with sockets for control rod assemtlies and collet tongs for control rods. Recharging is conducted by means of ramp channel

  18. Charge ratio of muons from atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Gaisser, T.K.; Stanev, Todor

    2003-05-22

    We calculate the intensities and angular distributions of positive and negative muons produced by atmospheric neutrinos. We comment on some sources of uncertainty in the charge ratio. We also draw attention to a potentially interesting signature of neutrino oscillations in the muon charge ratio, and we discuss the prospects for its observation (which are not quite within the reach of currently planned magnetized detectors)

  19. Organophosphorus flame retardants and heavy metals in municipal landfill leachate treatment system in Guangzhou, China.

    Science.gov (United States)

    Deng, Mingjun; Kuo, Dave T F; Wu, Qihang; Zhang, Ying; Liu, Xinyu; Liu, Shengyu; Hu, Xiaodong; Mai, Bixian; Liu, Zhineng; Zhang, Haozhi

    2018-05-01

    The occurrence, distribution and removal efficiencies of organophosphorus flame retardants (OPFRs) and metals were examined in a municipal landfill leachate treatment system in Guangzhou, China. Five OPFRs and thirty-five metals were detected in wastewater samples collected at different treatment stages. ∑OPFRs was reduced from 4807.02 ng L -1 to 103.91 ng L -1 through the treatment system, with close to 98% removed from the dissolved phase. Tris(clorisopropyl) phosphates (TCPPs) dominated through the treatment process and accounted for over 80% and 50% of ∑OPFRs at the influent and the effluent, respectively. TCPPs were most efficiently removed (98.6%) followed by tris(2-chloroethyl) phosphate (TCEP) (96.6%) and triphenyl phosphate (TPP) (88.5%). For metals, Fe, Cr, and Rb were dominant in the raw leachate, detected at 7.55, 2.82, and 4.50 mg L -1 , respectively. Thirteen regulated heavy metals - including eight major pollutants (i.e., As. Cd, Cr, Cu, Hg, Ni, Pb, and Zn) - have been detected in all wastewater samples at sub-mg L -1 levels. Over 99.5% removal was achieved for Cr, Ni, and Fe, and close to 95% removal efficiency was observed for Rb. For the eight major heavy metals, over 99% removal was observed; the only exception was Cu, which was removed at 89%. It was found that microfiltration/reverse osmosis was critical for the removal of OPFRs and heavy metals while the core biological treatment played a minor role towards their removal. Remobilization of Co, Cu, Fe, Hg, Mn, Ni, Sb, and Sr from the returned sludge occurred during the second denitrification, indicating the need for additional post-biological process for effective removal of both contaminants. This study highlights the critical need to develop cheap, effective treatment technologies for contaminants-laden leachate generated from open dumps and under-designed landfills. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Distinct patterns of gene and protein expression elicited by organophosphorus pesticides in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Dennis William E

    2009-04-01

    Full Text Available Abstract Background The wide use of organophosphorus (OP pesticides makes them an important public health concern. Persistent effects of exposure and the mechanism of neuronal degeneration are continuing issues in OP toxicology. To elucidate early steps in the mechanisms of OP toxicity, we studied alterations in global gene and protein expression in Caenorhabditis elegans exposed to OPs using microarrays and mass spectrometry. We tested two structurally distinct OPs (dichlorvos and fenamiphos and employed a mechanistically different third neurotoxicant, mefloquine, as an out-group for analysis. Treatment levels used concentrations of chemical sufficient to prevent the development of 10%, 50% or 90% of mid-vulval L4 larvae into early gravid adults (EGA at 24 h after exposure in a defined, bacteria-free medium. Results After 8 h of exposure, the expression of 87 genes responded specifically to OP treatment. The abundance of 34 proteins also changed in OP-exposed worms. Many of the genes and proteins affected by the OPs are expressed in neuronal and muscle tissues and are involved in lipid metabolism, cell adhesion, apoptosis/cell death, and detoxification. Twenty-two genes were differentially affected by the two OPs; a large proportion of these genes encode cytochrome P450s, UDP-glucuronosyl/UDP-glucosyltransferases, or P-glycoproteins. The abundance of transcripts and the proteins they encode were well correlated. Conclusion Exposure to OPs elicits a pattern of changes in gene expression in exposed worms distinct from that of the unrelated neurotoxicant, mefloquine. The functional roles and the tissue location of the genes and proteins whose expression is modulated in response to exposure is consistent with the known effects of OPs, including damage to muscle due to persistent hypercontraction, neuronal cell death, and phase I and phase II detoxification. Further, the two different OPs evoked distinguishable changes in gene expression; about half

  1. Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web.

    Science.gov (United States)

    Brandsma, Sicco H; Leonards, Pim E G; Leslie, Heather A; de Boer, Jacob

    2015-02-01

    Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of the PFRs (6-56%) was lower than that of the BFRs (50-97%). Tris(2-butoxyethyl) phosphate (TBOEP), tris(isobutyl) phosphate (TIBP) and tris(2-chloroisopropyl) phosphate (TCIPP) were the dominant PFRs in sediment with median concentrations of 7.0, 8.1 and 1.8 ng/g dry weight (dw), respectively. PFR levels in the suspended particular matter (SPM) were 2-12 times higher than that in sediment. TBOEP, TCIPP, TIBP, tris(2-chloroethyl) phosphate (TCEP) and tris(phenyl) phosphate (TPHP) were found in organisms higher in the estuarine food web. The highest PFR concentrations in the benthic food web were found in sculpin, goby and lugworm with median concentrations of 17, 7.4, 4.6 and 2.0 ng/g wet weight (ww) for TBOEP, TIBP, TCIPP and TPHP, respectively. Comparable levels were observed in the pelagic food web, BDE209 was the predominant PBDE in sediment and SPM with median concentrations up to 9.7 and 385 ng/g dw, respectively. BDE47 was predominant in the biotic compartment of the food web with highest median levels observed in sculpin and common tern eggs of 79 ng/g lipid weight (lw) (2.5 ng/g ww) and 80 ng/g lw (11 ng/g ww), respectively. Trophic magnification was observed for all PBDEs with the exception of BDE209. Indications of trophic magnification of PFRs were observed in the benthic food web for TBOEP, TCIPP and TCEP with tentative trophic magnification factors of 3.5, 2.2 and 2.6, respectively (pwebs. The relative high PFR levels in several fish species suggest high emissions and substantial exposure of organisms to PFRs in the Western Scheldt. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Analysis of monomeric and oligomeric organophosphorus flame retardants in fish muscle tissues using liquid chromatography–electrospray ionization tandem mass spectrometry: Application to Nile tilapia (Oreochromis niloticus) from an e-waste processing area in northern Vietnam

    OpenAIRE

    Matsukami, Hidenori; Suzuki, Go; Tue, Nguyen Minh; Tuyen, Le Huu; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke; Takigami, Hidetaka

    2016-01-01

    Using electrospray ionization tandem mass spectrometry combined with liquid chromatography (LC), a novel analytical method was developed to quantify eight monomeric organophosphorus flame retardants (m-PFRs) and three oligomeric organophosphorus flame retardants (o-PFRs) in fish muscle samples. The optimization and validation experiments indicate that the developed method can determine accurately the concentrations of analytes in fish muscle samples. The recoveries of analytes in fish muscle ...

  3. Dosimeter charging and/or reading apparatus

    International Nuclear Information System (INIS)

    Fine, L.T.; Jackson, T.P.

    1980-01-01

    A device is disclosed for charging and/or reading a capacitor associated with an electrometer incorporated in a radiation dosimeter for the purpose of initializing or ''zeroing'', the dosimeter at the commencement of a radiation measurement cycle or reading it at any time thereafter. The dosimeter electrometer has a movable electrode the position of which is indicative of the charge remaining on the dosimeter capacitor and in turn the amount of radiation incident on the dosimeter since it was zeroed. The charging device also includes means for discharging, immediately upon conclusion of the dosimeter capacitor charging operation, stray capacitance inherent in the dosimeter by reason of its mechanical construction. The charge on the stray capacitance, if not discharged at the conclusion of the dosimeter capacitor charging operation, leaks off during the measurement cycle, introducing measurement errors. A light source and suitable switch means are provided for automatically illuminating the movable electrode of the dosimeter electrometer as an incident to charging the dosimeter capacitor to facilitate reading the initial, or ''zero'', position of the movable electrometer electrode after the dosimeter capacitor has been charged and the stray capacitance discharged. Also included is a manually actuatable switch means, which is operable independently of the aforementioned automatic switch means, to energize the lamp and facilitate reading of the dosimeter without charging

  4. Compostos organofosforados pentavalentes: histórico, métodos sintéticos de preparação e aplicações como inseticidas e agentes antitumorais Organophosphorus pentavalent compounds: history, synthetic methods of preparation and application as insecticides and antitumor agents

    Directory of Open Access Journals (Sweden)

    Viviane Martins Rebello dos Santos

    2007-02-01

    Full Text Available This paper is a review of the history, synthesis and application of organophosphorus compounds, especially of those of pentavalent phosphorus, such as phosphoramidates, phosphorothioates, phosphonates and phosphonic acids with insecticide and anticancer activities. The organophosphorus compounds with agrochemical applications show great structural variety, They include not only insecticides, but also fungicides, herbicides, and others. The large variety of commercially available organophosphorus pesticides is remarkable. Even more interesting is the high efficiency of some organophosphorus compounds as anticancer agents such as cyclophosphamide and its derivatives.

  5. Degradation of Organophosphorus Pesticides in Water during UV/H2O2 Treatment: Role of Sulphate and Bicarbonate Ions

    Directory of Open Access Journals (Sweden)

    Am Fadaei

    2012-01-01

    Full Text Available The photodegradation of two organophosphorus pesticides, malathian and diazinon, by sulfate radicals and bicarbonate radicals in aqueous solution were studied. The effect of the operational parameters such as pH, salt concentration, water type, H2O2 concentration and initial concentration of pesticides was studied. Gas chromatography mass spectroscopy (GC–MS was used for analyses of pesticides. When salt effect was studied, it was found that sodium bicarbonate was the most powerful inhibitor used, while sodium sulfate was the weakest one. The highest degradation in UV/H2O2 process for malathion was found in alkaline condition and for diazinon in acidic condition. The photodegradation in all waters used in this work exhibited first order kinetics. Photodegradation rate in distilled water was higher than real water. The degradation of pesticides increased with increasing of H2O2 concentration.

  6. Effect of two organophosphorus insecticides on the growth, respiration and (/sup 14/C)-glucose metabolism of Azobacter chroococcum Beij

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, A; Narayanan, R [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1980-01-01

    The two organophosphorus insecticides, commonly applied to soil, viz., disulfoton (0,0-diethyl S-2-ethyl thio ethyl phosphorodithioate) and fensulfothion (0,0-diethyl 0-4-methyl sulphinyl phenyl phosphorothioate) did not affect the in vitro growth of Azotobacter chroococcum Beij., the free-living, nitrogen fixing soil bacterium, at 2 ppm (lower level), while the normal dose (5 ppm) and the higher level (10 ppm) suppressed the growth. Respiration of the organism (glucose oxidation) was adversely affected by the insecticides in the growth medium and the inhibition increased with the concentration of the chemical. Both the insecticides suppressed the assimilation of (/sup 14/C)-glucose in the cold-TCA soluble, hot-TCA soluble fractions and insoluble residue of the cells whereas the /sup 14/C-incorporation in the alcohol soluble and alcohol-ether soluble fractions was enhanced indicating that the insecticides considerably altered the glucose metabolism of the bacterium.

  7. [How aliphatic alcohols and ph affect reactional capability of the horse blood serum cholinesterase at its interaction with organophosphorus inhibitors].

    Science.gov (United States)

    Basova, N E; Kormilitsin, B N; Perchenok, A Iu; Rozengart, E V; Saakov, V S; Suvorov, A A

    2013-01-01

    There was studied action of aliphatic alcohols (ethanol, propanol, isopropanol, n-butanol, isobutanol, secbutanol, tretbetanol) and pH on various kinds of reactional capability the serum cholinesterase. At the alcohols-affected inhibition of the cholinesterase hydrolytic activity, the determining role was played not the total number carbon atoms in the alcohol molecule, but by the "effective length" of the carbohydrate chain. The fact that the presence of alcohols did not affect parameters of the reverse cholinesterase inhibition with onium ions tetramethylammonium and choline allows suggesting the absence of effect solvents on specific acetylcholine sorption in the enzyme active center. With aid of two rows of hydrophobic organophosphorus inhibitors (OPI), we have managed to estimate both the degree and the character itself of the modifying action of alcohols and pH on the process of irreversible inhibition of serum cholinesterase.

  8. [Comparative analysis of sensitivity of proteases (chymotrypsin and trypsin) and cholinesterases of different origin to some organophosphorus inhibitors].

    Science.gov (United States)

    Rozengart, E V

    2009-01-01

    The antichymotrypsin, antitrypsin, and anticholinesterase efficiencies of four homologous series of organophosphorus inhibitors are compared: O-ethyl-S-(n-alkyl)methylthiophosphonates, O-(n-alkyl)-S-(n-butyl)methylthiophosphonates, O-(n-alkyl)-S-beta-(ethylmercaptoethylene)methylthiophosphonates, and their methylsulfomethylates. As sources of a-chymotrypsin and trypsin, commercial compounds of Worthington Biochemical Corporation and Leningrad Myasokombinat were tested. Bimolecular constant of the reaction rate was used as the measure of antienzyme efficiency. In all cases, the antichymotrypsin efficiency was lower, while the antitrypsin--essentially higher than the anticholinesterase activity of the studied inhibitors. These differences were found to much depend both on the inhibitor structure and on nature of the cholinesterase compounds.

  9. Towards a Capacitive Enzyme Sensor for Direct Determination of Organophosphorus Pesticides: Fundamental Studies and Aspects of Development

    Directory of Open Access Journals (Sweden)

    Ashok Mulchandani

    2003-06-01

    Full Text Available The realisation of a miniaturised potentiometric enzyme biosensor is presented. The biosensor chip utilises the enzyme organophosphorus hydrolase (OPH for the direct determination of pesticides. The transducer structure of the sensors chip consists of a pH-sensitive capacitive electrolyte-insulator-semiconductor (EIS structure that reacts towards pH changes caused by the OPH-catalised hydrolysis of the organophosphate compounds. The biosensor is operated versus a conventional Ag/AgCl reference electrode. Measurements were performed in the capacitance/voltage (C/V and the constant capacitance (ConCap mode for the two different pesticides paraoxon and parathion. For the development of this new type of biosensor, different immobilisation strategies, influence of buffer composition and concentration, transducer material, detection limit, long-term stability and selectivity have been studied.

  10. Effect of two organophosphorus insecticides on the growth, respiration and (14C)-glucose metabolism of Azobacter chroococcum Beij

    International Nuclear Information System (INIS)

    Balasubramanian, A.; Narayanan, R.

    1980-01-01

    The two organophosphorus insecticides, commonly applied to soil, viz., disulfoton (0,0-diethyl S-2-ethyl thio ethyl phosphorodithioate) and fensulfothion (0,0-diethyl 0-4-methyl sulphinyl phenyl phosphorothioate) did not affect the in vitro growth of Azotobacter chroococcum Beij., the free-living, nitrogen fixing soil bacterium, at 2 ppm (lower level), while the normal dose (5 ppm) and the higher level (10 ppm) suppressed the growth. Respiration of the organism (glucose oxidation) was adversely affected by the insecticides in the growth medium and the inhibition increased with the concentration of the chemical. Both the insecticides suppressed the assimilation of ( 14 C)-glucose in the cold-TCA soluble, hot-TCA soluble fractions and insoluble residue of the cells whereas the 14 C-incorporation in the alcohol soluble and alcohol-ether soluble fractions was enhanced indicating that the insecticides considerably altered the glucose metabolism of the bacterium. (author)

  11. On Dust Charging Equation

    OpenAIRE

    Tsintsadze, Nodar L.; Tsintsadze, Levan N.

    2008-01-01

    A general derivation of the charging equation of a dust grain is presented, and indicated where and when it can be used. A problem of linear fluctuations of charges on the surface of the dust grain is discussed.

  12. Electrophysiologic changes following treatment with organophosphorus-induced delayed neuropathy-producing agents in the adult hen.

    Science.gov (United States)

    Robertson, D G; Schwab, B W; Sills, R D; Richardson, R J; Anderson, R J

    1987-03-15

    Although clinical, pathological, and biochemical effects of organophosphorus-induced delayed neuropathy (OPIDN) have been intensively investigated in the adult hen, detailed electrophysiological studies are lacking. Adult white leghorn hens were treated with a single oral dose of either 30 mg/kg tri-2-cresyl phosphate (TOCP), 750 mg/kg TOCP, 4 mg/kg di-n-butyl-2,2-dichlorovinyl phosphate (DBCV), or 30 mg/kg di-n-butyl-2,2-dichlorovinyl phosphinate (DBCV-P). The 750 mg/kg TOCP and DBCV, but not the 30 mg/kg TOCP and DBCV-P, treatments resulted in clinical signs of OPIDN and mild to marked damage of the tibial nerve 21 days after dose. Twenty-four hr lymphocyte neurotoxic esterase (NTE) inhibition was used as an index of brain NTE inhibition for the various organophosphorus compound (OP) treatment. Twenty-four hr lymphocyte NTE inhibition for 30 mg/kg TOCP, 750 mg/kg TOCP, DBCV, and DBCV-P was 54.1, 87.1, 84.8, and 68.3%, respectively. Twenty-one days after dose, the TOCP-treated hens exhibited some abnormalities in conduction velocity and action potential duration in the tibial or sciatic nerves. No abnormalities were observed in action potential parameters of either the DBCV or DBCV-P treatments. Neurotoxic OP (TOCP and DBCV) treatment resulted in decreased refractoriness in the tibial nerve, increased refractoriness in the sciatic nerve, and elevated strength duration threshold for both nerves. These changes were not present in nerves from DBCV-P (a non-neurotoxic NTE inhibitor)-treated hens. These results suggest that refractory period and strength duration abnormalities in peripheral nerve correlate well with the production of OPIDN and are evident without coincident clinical signs or histopathology.

  13. Determination of no-observed effect level (NOEL-biomarker equivalents to interpret biomonitoring data for organophosphorus pesticides in children

    Directory of Open Access Journals (Sweden)

    Bouchard Michèle

    2009-02-01

    Full Text Available Abstract Background Environmental exposure to organophosphorus pesticides has been characterized in various populations, but interpretation of these data from a health risk perspective remains an issue. The current paper proposes biological reference values to help interpret biomonitoring data related to an exposure to organophosphorus pesticides in children for which measurements of alkylphosphate metabolites are available. Methods Published models describing the kinetics of malathion and chlorpyrifos in humans were used to determine no-observed effect level – biomarker equivalents for methylphosphates and ethylphosphates, respectively. These were expressed in the form of cumulative urinary amounts of alkylphosphates over specified time periods corresponding to an absorbed no-observed effect level dose (derived from a published human exposure dose and assuming various plausible exposure scenarios. Cumulative amounts of methylphosphate and ethylphosphate metabolites measured in the urine of a group of Quebec children were then compared to the proposed biological reference values. Results From a published no-observed effect level dose for malathion and chlorpyrifos, the model predicts corresponding oral biological reference values for methylphosphate and ethylphosphate derivatives of 106 and 52 nmol/kg of body weight, respectively, in 12-h nighttime urine collections, and dermal biological reference values of 40 and 32 nmol/kg of body weight. Out of the 442 available urine samples, only one presented a methylphosphate excretion exceeding the biological reference value established on the basis of a dermal exposure scenario and none of the methylphosphate and ethylphosphate excretion values were above the obtained oral biological reference values, which reflect the main exposure route in children. Conclusion This study is a first step towards the development of biological guidelines for organophophorus pesticides using a toxicokinetic modeling

  14. Determination of some organophosphorus pesticides in water and watermelon samples by microextraction prior to high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Chun; Wu, Qiuhua; Wu, Chunxia; Wang, Zhi

    2011-11-01

    A novel method based on simultaneous liquid-liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-liquid phase microextraction has been developed for the determination of six organophosphorus pesticides, i.e. isocarbophos, phosmet, parathion-methyl, triazophos, fonofos and phoxim, in water and watermelon samples prior to high-performance liquid chromatography (HPLC). Under the optimum conditions, the method shows a good linearity within a range of 1-200 ng/mL for water samples and 5-200 ng/g for watermelon samples, with the correlation coefficients (r) varying from 0.9990 to 0.9997 and 0.9986 to 0.9995, respectively. The limits of detection (LODs) were in the range between 0.1 and 0.3 ng/mL for water samples and between 1.0 and 1.5 ng/g for watermelon samples. The recoveries of the method at spiking levels of 5.0 and 50.0 ng/mL for water samples were between 85.4 and 100.8%, and at spiking levels of 5.0 and 50.0 ng/g for watermelon samples, they were between 82.6 and 92.4%, with the relative standard deviations (RSDs) varying from 4.5-6.9% and 5.2-7.4%, respectively. The results suggested that the developed method represents a simple, low-cost, high analytes preconcentration and excellent sample cleanup procedure for the determination of organophosphorus pesticides in water and watermelon samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. In vitro study of the neuropathic potential of the organophosphorus compounds fenamiphos and profenofos: Comparison with mipafox and paraoxon.

    Science.gov (United States)

    Emerick, Guilherme L; Fernandes, Laís S; de Paula, Eloísa Silva; Barbosa, Fernando; dos Santos, Neife Aparecida Guinaim; dos Santos, Antonio Cardozo

    2015-08-01

    Organophosphorus-induced delayed neuropathy (OPIDN) is a central-peripheral distal axonopathy that develops 8-14 days after poisoning by a neuropathic organophosphorus compound (OP). Several OPs that caused OPIDN were withdrawn from the agricultural market due to induction of serious delayed effects. Therefore, the development of in vitro screenings able to differentiate neuropathic from non-neuropathic OPs is of crucial importance. Thus, the aim of this study was to evaluate the differences in the neurotoxic effects of mipafox (neuropathic OP) and paraoxon (non-neuropathic OP) in SH-SY5Y human neuroblastoma cells, using the inhibition and aging of neuropathy target esterase (NTE), inhibition of acetylcholinesterase (AChE), activation of calpain, neurite outgrowth, cytotoxicity and intracellular calcium as indicators. Additionally, the potential of fenamiphos and profenofos to cause acute and/or delayed effects was also evaluated. Mipafox had the lowest IC50 and induced the highest percentage of aging of NTE among the OPs evaluated. Only mipafox was able to cause calpain activation after 24 h of incubation. Concentrations of mipafox and fenamiphos which inhibited at least 70% of NTE were also able to reduce neurite outgrowth. Cytotoxicity was higher in non-neuropathic than in neuropathic OPs while the intracellular calcium levels were higher in neuropathic than in non-neuropathic OPs. In conclusion, the SH-SY5Y cellular model was selective to differentiate neuropathic from non-neuropathic OPs; fenamiphos, but not profenofos presented results compatible with the induction of OPIDN. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Rapid simultaneous determination of organophosphorus pesticides in human serum and urine by liquid chromatography-mass spectrometry

    Directory of Open Access Journals (Sweden)

    Zlatković Milica

    2010-01-01

    Full Text Available Background/Aim. Analysis of organophosphosphorus compounds and their metabolites in a biological material includes the use of numerous methods, covering both preparation of samples for analysis and their identification that is considered to be very complex. Low concentrations monitoring requires implementation of highly sensitive analytical techniques. The aim of this study was to develop and validate an original and sensitive method for the detection and quantitation of organophosphorus pesticides (dimethoate, diazinon, malathion and malaoxon in human biological matrices (serum, urine. Methods. This method was based on a solid-phase extraction procedure, a chromatographic separation using an ACQUITY UPLC ® HSST3 column and mass spectrometric detection in the positve ion mode. Mobile phase: was consited of Solvent A (5 mM ammonium formate pH 3.0 and Solvent B (0.1% acetic formate in methanol, in a linear gradient (constant flow-rate 0.3 mL/min. Results. The standard curve was linear in the range of 0.05-5.00 mg/L for malathion and malaoxon, 0.10-5.00 mg/L for dimethoate and 0.05-2.50 mg/L for diazinon. The correlation coefficient was r ≥ 0.99. Extraction recoveries were satisfactory and ranged between 90-99%. The limits of detection (LOD was between 0.007- 0.07 mg/L and the limits of quantitation (LOQ ranged between 0.022-0.085 mg/L. Intra- and interassay precision and accuracy were satisfactory for all of the pesticides analyzed. Conclusion. The method of liquid chromatography - mass spectrometry is simple, accurate, and useful for the determination of organophosphorus pesticides in both clinical and forensic toxicology.

  17. Linear shaped charge

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, David; Stofleth, Jerome H.; Saul, Venner W.

    2017-07-11

    Linear shaped charges are described herein. In a general embodiment, the linear shaped charge has an explosive with an elongated arrowhead-shaped profile. The linear shaped charge also has and an elongated v-shaped liner that is inset into a recess of the explosive. Another linear shaped charge includes an explosive that is shaped as a star-shaped prism. Liners are inset into crevices of the explosive, where the explosive acts as a tamper.

  18. Color and magnetic charge

    International Nuclear Information System (INIS)

    Kim, B.R.

    1976-01-01

    Schwinger's conjecture that the color degree of freedom of a quark is equivalent to its degree of freedom of taking different magnetic charges provides a plausible motivation for extending color to leptons. Leptons are just quarks with zero magnetic charges. It is shown that baryon number and lepton number can be replaced by fermion number and magnetic charge

  19. Submicron position-sensitive detector

    Energy Technology Data Exchange (ETDEWEB)

    Pugatch, V M; Rosenfeld, A B; Litovchenko, P G; Barabash, L I; Nemets, O F; Pavlenko, Yu N; Vasiliev, Yu O [Ukrainian Academy of Sciences, Kiev (Ukraine). Inst. for Nuclear Research

    1992-08-01

    A method has been developed to measure precisely the coordinates of charged particles incident between adjacent strips of a strip detector. The position sensitivity of an inter-strip gap has been studied by means of a pulsed laser beam and irradiation by [alpha]-particles of a [sup 226]Ra-source. The capacitive division of charge generated by the incident particle depends on the position of its track. Its coordinates were determined by two-dimensional amplitude analysis of the charges collected by neighbouring strips. This method of coordinate determination applied to studies of spatial and energy distributions of electromagnetic as well as charged particle beams (including radioactive ion beams) of low intensity could provide the highest level of the precision limited by the track dimensions of charged particles, i.e. percents of a micrometer. (orig.).

  20. Space Charge Effects

    CERN Document Server

    Ferrario, M.; Palumbo, L.

    2014-12-19

    The space charge forces are those generated directly by the charge distribution, with the inclusion of the image charges and currents due to the interaction of the beam with a perfectly conducting smooth pipe. Space charge forces are responsible for several unwanted phenomena related to beam dynamics, such as energy loss, shift of the synchronous phase and frequency , shift of the betatron frequencies, and instabilities. We will discuss in this lecture the main feature of space charge effects in high-energy storage rings as well as in low-energy linacs and transport lines.

  1. Charge of a macroscopic particle in a plasma sheath

    International Nuclear Information System (INIS)

    Samarian, A.A.; Vladimirov, S.V.

    2003-01-01

    Charging of a macroscopic body levitating in a rf plasma sheath is studied experimentally and theoretically. The nonlinear charge vs size dependence is obtained. The observed nonlinearity is explained on the basis of an approach taking into account different plasma conditions for the levitation positions of different particles. The importance of suprathermal electrons' contribution to the charging process is demonstrated

  2. A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology

    Directory of Open Access Journals (Sweden)

    Yong Pan

    2014-05-01

    Full Text Available This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylenethio

  3. Effect of surface charge of immortalized mouse cerebral endothelial cell monolayer on transport of charged solutes.

    Science.gov (United States)

    Yuan, Wei; Li, Guanglei; Gil, Eun Seok; Lowe, Tao Lu; Fu, Bingmei M

    2010-04-01

    Charge carried by the surface glycocalyx layer (SGL) of the cerebral endothelium has been shown to significantly modulate the permeability of the blood-brain barrier (BBB) to charged solutes in vivo. The cultured monolayer of bEnd3, an immortalized mouse cerebral endothelial cell line, is becoming a popular in vitro BBB model due to its easy growth and maintenance of many BBB characteristics over repeated passages. To test whether the SGL of bEnd3 monolayer carries similar charge as that in the intact BBB and quantify this charge, which can be characterized by the SGL thickness (L(f)) and charge density (C(mf)), we measured the solute permeability of bEnd3 monolayer to neutral solutes and to solutes with similar size but opposite charges: negatively charged alpha-lactalbumin (-11) and positively charged ribonuclease (+3). Combining the measured permeability data with a transport model across the cell monolayer, we predicted the L(f) and the C(mf) of bEnd3 monolayer, which is approximately 160 nm and approximately 25 mEq/L, respectively. We also investigated whether orosomucoid, a plasma glycoprotein modulating the charge of the intact BBB, alters the charge of bEnd3 monolayer. We found that 1 mg/mL orosomucoid would increase SGL charge density of bEnd3 monolayer to approximately 2-fold of its control value.

  4. Actinide immobilization in the subsurface environment by in-situ treatment with a hydrolytically unstable organophosphorus complexant: Uranyl uptake by calcium phytate

    International Nuclear Information System (INIS)

    Nash, K.L.; Jensen, M.P.; Schmidt, M.A.

    1997-01-01

    In addition to naturally occurring uranium and thorium, actinide ions exist in the subsurface environment as a result of accidental releases and intentional disposal practices associated with nuclear weapons production. These species present a significant challenge to cost-effective remediation of contaminated environments. An attractive approach to decreasing the probability of actinide migration in the subsurface is to transform the ions into a less mobile form by remote treatment. We have under development a process which relies on a polyfunctional organophosphorus complexant to sequester the mobile metal ions by complexation/cation exchange in the near term, and to subsequently decompose, transforming the actinides into insoluble phosphate mineral forms in the long term. Studies to date include identification of a suitable organophosphorus reagent, profiling of its decomposition kinetics, verification of the formation of phosphate mineral phases upon decomposition of the reagent, and extensive comparison of the actinide uptake ability of the calcium salt of the reagent as compared with hydroxyapatite. In this report, we briefly describe the process with focus on the cation exchange behavior of the calcium salt of the organophosphorus sequestrant

  5. [Feasibility investigation of hydrogen instead of helium as carrier gas in the determination of five organophosphorus pesticides by gas chromatography-mass spectrometry].

    Science.gov (United States)

    Liu, Zhenxue; Zhou, Shixue

    2015-01-01

    Helium is almost the only choosable carrier gas used in gas chromatography-mass spectrometry (GC-MS). A mixed standard solution of five organophosphorus pesticides was analyzed by using GC-MS, and hydrogen or helium as carrier gas, so as to study the feasibility of hydrogen instead of helium as carrier gas for the determination of organophosphorus pesticides. Combining a mass spectrum database built by ourselves, the results were deconvolved and identified by Automated Mass Spectral Deconvolution & Identification System (AMDIS32), a software belonging to the workstation of the instrument. Then, the statistical software, IBM SPSS Statistics 19.0 was used for the clustering analysis of the data. The results indicated that when hydrogen was used as carrier gas, the peaks of the pesticides detected were slightly earlier than those when helium used as carrier gas, but the resolutions of the chromatographic peaks were lower, and the fraction good indices (Frac. Good) were lower, too. When hydrogen was used as carrier gas, the signals of the pesticides were unstable, the measuring accuracies of the pesticides were reduced too, and even more, some compounds were undetectable. Therefore, considering the measuring accuracy, the signal stability, and the safety, etc., hydrogen should be cautiously used as carrier gas in the determination of organophosphorus pesticides by GC-MS.

  6. Comparison of the Efficiency of Simultaneous Application of UV/O3 for the Removal of Organophosphorus and Carbamat Pesticides in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Samadi

    2010-03-01

    Full Text Available A vast variety of pesticides are used for agricultural pests in Iran. The release of these persistent organic pollutants. into water supplies leaves adverse effects on both the environment and public health. Advanced oxidation processes have been used recently for pesticide removal. In this research, the combined UV/O3 process has been investigated for the removal of organophosphorus pesticides (Diazinon, Chlorpyrifos, Carbamate pesticides (carbaryl. In this survey, samples have been prepared by adding given concentration (1, 5, 10, 15, 20 mg/L of the pesticides to deionized water. The samples at separation periods were exposed to the combined UV/O3 (UV=50-200 Wm-2 and O3 = 1g hr-1in a bath  reactor at different pH levels (6, 7, 9 and for different contact times (0.5,1,1.5,2 hr and the removal efficiencies were determined. Residual concentrations were determined using GC/MS/MS and HPLC.  Based on the results, increasing pH reduced pesticide concentration and increased contact time had a direct effect on enhancing removal efficiency. The combined UV/O3 process was found to have a high efficiency (>80% in degrading both halogenated Organophosphorus(Chlorpyrifos and non- halogenated Organophosphorus (Diazinon pesticides. Its removal efficiency for degrading carbamate pesticide (Carbari was found to be >90%. Based on our results, this method may be suggested for the removal of pesticides from aqueous solutions.

  7. Searches for Fractionally Charged Particles: What Should Be Done Next?

    Energy Technology Data Exchange (ETDEWEB)

    Perl, Martin L.; /SLAC

    2009-01-15

    Since the initial measurements of the electron charge a century ago, experimenters have faced the persistent question as to whether elementary particles exist that have charges that are fractional multiples of the electron charge. I concisely review the results of the last 50 years of searching for fractional charge particles with no confirmed positive results. I discuss the question of whether more searching is worthwhile?

  8. Coulombic charge ice

    Science.gov (United States)

    McClarty, P. A.; O'Brien, A.; Pollmann, F.

    2014-05-01

    We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

  9. Cooperative Charging Effects of Fibers From Electrospinning of Electrically Dissimilar Polymers

    National Research Council Canada - National Science Library

    Schreuder-Gibson, H. L; Gibson, P; Tsai, P; Gupta, P; Wilkes, G

    2005-01-01

    .... During electrospinning of the PS and PAN polymer solutions, the fibers became positively charged when positive voltage was applied to the solution-filled spinning nozzle and became negatively charged...

  10. Galvanic Cells: Anodes, Cathodes, Signs and Charges

    Science.gov (United States)

    Goodwin, Alan

    2011-01-01

    Electrochemistry is a difficult subject for students at school and beyond and even for their teachers. This article explores the difficult "truth" that, when a current flows from a galvanic cell, positive ions within the cell electrolyte move towards the electrode labelled positive. This seems to contravene the basic rule that like charges repel…

  11. Jet Vertex Charge Reconstruction

    CERN Document Server

    Nektarijevic, Snezana; The ATLAS collaboration

    2015-01-01

    A newly developed algorithm called the jet vertex charge tagger, aimed at identifying the sign of the charge of jets containing $b$-hadrons, referred to as $b$-jets, is presented. In addition to the well established track-based jet charge determination, this algorithm introduces the so-called \\emph{jet vertex charge} reconstruction, which exploits the charge information associated to the displaced vertices within the jet. Furthermore, the charge of a soft muon contained in the jet is taken into account when available. All available information is combined into a multivariate discriminator. The algorithm has been developed on jets matched to generator level $b$-hadrons provided by $t\\bar{t}$ events simulated at $\\sqrt{s}$=13~TeV using the full ATLAS detector simulation and reconstruction.

  12. Charge Islands Through Tunneling

    Science.gov (United States)

    Robinson, Daryl C.

    2002-01-01

    It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

  13. Contractor Software Charges

    National Research Council Canada - National Science Library

    Granetto, Paul

    1994-01-01

    .... Examples of computer software costs that contractors charge through indirect rates are material management systems, security systems, labor accounting systems, and computer-aided design and manufacturing...

  14. Collisional charging of individual submillimeter particles: Using ultrasonic levitation to initiate and track charge transfer

    Science.gov (United States)

    Lee, Victor; James, Nicole M.; Waitukaitis, Scott R.; Jaeger, Heinrich M.

    2018-03-01

    Electrostatic charging of insulating fine particles can be responsible for numerous phenomena ranging from lightning in volcanic plumes to dust explosions. However, even basic aspects of how fine particles become charged are still unclear. Studying particle charging is challenging because it usually involves the complexities associated with many-particle collisions. To address these issues, we introduce a method based on acoustic levitation, which makes it possible to initiate sequences of repeated collisions of a single submillimeter particle with a flat plate, and to precisely measure the particle charge in situ after each collision. We show that collisional charge transfer between insulators is dependent on the hydrophobicity of the contacting surfaces. We use glass, which we modify by attaching nonpolar molecules to the particle, the plate, or both. We find that hydrophilic surfaces develop significant positive charges after contacting hydrophobic surfaces. Moreover, we demonstrate that charging between a hydrophilic and a hydrophobic surface is suppressed in an acidic environment and enhanced in a basic one. Application of an electric field during each collision is found to modify the charge transfer, again depending on surface hydrophobicity. We discuss these results within the context of contact charging due to ion transfer, and we show that they lend strong support to O H- ions as the charge carriers.

  15. Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

    Energy Technology Data Exchange (ETDEWEB)

    Azab, Hassan A., E-mail: azab2@yahoo.com; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

    2015-01-15

    This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN){sub 2}(Phen)(H{sub 2}O){sub 2}]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion

  16. Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

    International Nuclear Information System (INIS)

    Azab, Hassan A.; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

    2015-01-01

    This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN) 2 (Phen)(H 2 O) 2 ]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion, Endosulfan, and

  17. Effect of Intensive Atropine Doses (Rapid Incremental Loading and Titration for Management of Organophosphorus Pesticide Poisoning: a Case Series

    Directory of Open Access Journals (Sweden)

    Abu Saleh Ahmed

    2014-03-01

    Full Text Available Background:Acute poisoning with organophosphorus (OP pesticides is a common method of suicide and entails considerable mortality in Bangladesh. The objective of this study was to evaluate the effects and outcomes of a protocol for treatment of OP poisoning that included titrated incremental atropine as loading dose and slow infusion for maintenance.  Methods:In this prospective descriptive case series, definitive OP poisoned patients were enrolled in an adult medicine unit of Dhaka Medical College Hospital from April 2006 to April 2007. Clinical examinations were done as soon as the patient entered the ward. Patient’s demographics, comorbid conditions and the occurrence of specific clinical outcomes including death, need for assisted ventilation and clinical complications were recorded. The patients were treated according to the protocol. Results: A total of 56 patients were enrolled over the study period. The median age of the study population was 22.5 years. Most patients were men (67.8%. The most common clinical presentation was miosis (58.9%. In total, 11 patients died (19.6%. Intermediate syndrome developed in 12 patients (21.4% and 6 of them died. Assisted ventilation was required in 16 cases (28.5. Patients with diastolic blood pressure ≤ 70 mmHg and/or GCS ≤ 10 were significantly less likely to survive (P = 0.02, 0.006, respectively. Moreover, early respiratory failure (P < 0.001 and the need for assisted ventilation (P < 0.001 were significantly higher among deceased cases. The mortality rate in this study was similar to previous studies. The frequency of atropine toxicity in the present study (1.8% was considerably lower than conventional regimen used in previous studies. Conclusion:Using the new protocol, lower rate of atropine toxicity developed in victims. Hence, the new protocol appears to be safer and its effectiveness should be further evaluated in case control studies in Bangladesh.    How to cite this article: Ahmed AS

  18. Poisoning of raptors with organophosphorus and carbamate pesticides with emphasis on Canada, U.S. and U.K.

    Science.gov (United States)

    Mineau, P.; Fletcher, M.R.; Glaser, L.C.; Thomas, N.J.; Brassard, C.; Wilson, L.K.; Elliott, J.E.; Lyon, L.A.; Henny, C.J.; Bollinger, T.; Porter, S.L.

    1999-01-01

    We reviewed cases of raptor mortality resulting from cholinesterase-inhibiting pesticides. We compiled records from the U.S., U.K. and Canada for the period 1985-95 (520 incidents) and surveyed the relevant literature to identify the main routes of exposure and those products that led to the greatest number of poisoning cases. A high proportion of cases in the U.K. resulted from abusive uses of pesticides (willful poisoning). The proportion was smaller in North America where problems with labeled uses of pesticides were as frequent as abuse cases. Poisoning resulting from labeled use was possible with a large number of granular pesticides and some seed treatments through secondary poisoning or through the ingestion of contaminated invertebrates, notably earthworms. With the more toxic products, residue levels in freshly-sprayed insects were high enough to cause mortality. The use of organophosphorus products as avicides and for the topical treatment of livestock appeared to be common routes of intoxication. The use of insecticides in dormant oils also gave rise to exposure that can be lethal or which can debilitate birds and increase their vulnerability. A few pesticides of high toxicity were responsible for the bulk of poisoning cases. Based on limited information, raptors appeared to be more sensitive than other bird species to organophosphorus and carbamate pesticides. Some of the more significant risk factors that resulted in raptor poisonings were: insectivory and vermivory; opportunistic taking of debilitated prey; scavenging, especially if the gastrointestinal tracts are consumed; presence in agricultural areas; perceived status as pest species; and flocking or other gregarious behavior at some part of their life cycle. Lethal or sublethal poisoning should always be considered in the diagnosis of dead or debilitated raptors even when another diagnosis (e.g., electrocution, car or building strike) is apparent. Many cases of poisoning are not currently

  19. Simultaneous detection of dual biomarkers from humans exposed to organophosphorus pesticides by combination of immunochromatographic test strip and ellman assay.

    Science.gov (United States)

    Yang, Mingming; Zhao, Yuting; Wang, Limin; Paulsen, Michael; Simpson, Christopher D; Liu, Fengquan; Du, Dan; Lin, Yuehe

    2018-05-01

    A novel sandwich immunoassay based immunochromatographic test strip (ICTS) has been developed for simultaneously measuring both butyrylcholinesterase (BChE) activity and the total amount of BChE (including inhibited and active enzyme) from 70 μLpost-exposure human plasma sample. The principle of this method is based on the BChE monoclonal antibody (MAb) capable of acting as both capture antibody and detection antibody. The BChE MAb which was immobilized on the test line was able to recognize both organophosphorus BChE adducts (OP-BChE) and BChE and provided equal binding affinity, permitting detection of the total enzyme amount in post-exposure human plasma samples. The formed immunocomplexes on the test line can further be excised from the test-strip for subsequent off-line measurement of BChE activity using the Ellman assay. Therefore, dual biomarkers of BChE activity and phosphorylation (OP-BChE) will be obtained simultaneously. The whole sandwich-immunoassay was performed on one ICTS, greatly reducing analytical time. The ICTS sensor showed excellent linear responses for assaying total amount of BChE and active BChE ranging from 0.22 to 3.58nM and 0.22-7.17nM, respectively. Both the signal detection limits are 0.10nM. We validated the practical application of the proposed method to measure 124 human plasma samples from orchard workers and cotton farmers with long-term exposure to organophosphorus pesticides (OPs). The results were in highly agreement with LC/MS/MS which verified our method is extremely accurate. Combining the portability and rapidity of test strip and the compatibility of BChE MAb as both capture antibody and detection antibody, the developed method provides a baseline-free, low-cost and rapid tool for in-field monitoring of OP exposures. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Charge Screening in a Charged Condensate

    International Nuclear Information System (INIS)

    Gabadadze, Gregory; Rosen, Rachel A.

    2009-01-01

    We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.

  1. Surface Charging and Points of Zero Charge

    CERN Document Server

    Kosmulski, Marek

    2009-01-01

    Presents Points of Zero Charge data on well-defined specimen of materials sorted by trademark, manufacturer, and location. This text emphasizes the comparison between particular results obtained for different portions of the same or very similar material and synthesizes the information published in research reports over the past few decades

  2. Electric vehicle battery charging controller

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides an electric vehicle charging controller. The charging controller comprises a first interface connectable to an electric vehicle charge source for receiving a charging current, a second interface connectable to an electric vehicle for providing the charging current...... to a battery management system in the electric vehicle to charge a battery therein, a first communication unit for receiving a charging message via a communication network, and a control unit for controlling a charging current provided from the charge source to the electric vehicle, the controlling at least...... in part being performed in response to a first information associated with a charging message received by the first communication unit...

  3. Radiation by moving charges

    International Nuclear Information System (INIS)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2017-04-01

    It is generally accepted that in order to describe the dynamics of relativistic particles in the laboratory (lab) frame it is sufficient to take into account the relativistic dependence of the particle momenta on the velocity. This solution of the dynamics problem in the lab frame makes no reference to Lorentz transformations. For this reason they are not discussed in particle tracking calculations in accelerator and plasma physics. It is generally believed that the electrodynamics problem can be treated within the same ''single inertial frame'' description without reference to Lorentz transformations. In particular, in order to evaluate radiation fields arising from charged particles in motion we need to know their velocities and positions as a function of the lab frame time t. The relativistic motion of a particle in the lab frame is described by Newton's second law ''corrected'' for the relativistic dependence of momentum on velocity. It is assumed in all standard derivations that one can perform identification of the trajectories in the source part of the usual Maxwell's equations with the trajectories vector x(t) measured (or calculated by using the corrected Newton's second law) in the lab frame. This way of coupling fields and particles is considered since more than a century as the relativistically correct procedure.We argue that this procedure needs to be changed, and we demonstrate the following, completely counterintuitive statement: the results of conventional theory of radiation by relativistically moving charges are not consistent with the principle of relativity. In order to find the trajectory of a particle in the lab frame consistent with the usual Maxwell's equations, one needs to solve the dynamic equation inmanifestly covariant form by using the coordinate-independent proper time τ to parameterize the particle world-line in space-time. We show that there is a difference between ''true'' particle trajectory vector x(t) calculated or measured in

  4. Dosimeter charging apparatus

    International Nuclear Information System (INIS)

    Reuter, F.A.; Moorman, Ch.J.

    1985-01-01

    An apparatus for charging a dosimeter which has a capacitor connected between first and second electrodes and a movable electrode in a chamber electrically connected to the first electrode. The movable electrode deflects varying amounts depending upon the charge present on said capacitor. The charger apparatus includes first and second charger electrodes couplable to the first and second dosimeter electrodes. To charge the dosimeter, it is urged downwardly into a charging socket on the charger apparatus. The second dosimeter electrode, which is the dosimeter housing, is electrically coupled to the second charger electrode through a conductive ring which is urged upwardly by a spring. As the dosimeter is urged into the socket, the ring moves downwardly, in contact with the second charger electrode. As the dosimeter is further urged downwardly, the first dosimeter electrode and first charger electrode contact one another, and an insulator post carrying the first and second charger electrodes is urged downwardly. Downward movement of the post effects the application of a charging potential between the first and second charger electrodes. After the charging potential has been applied, the dosimeter is moved further into the charging socket against the force of a relatively heavy biasing spring until the dosimeter reaches a mechanical stop in the charging socket

  5. Spacecraft Surface Charging Handbook

    Science.gov (United States)

    1992-11-01

    Charging of Large Spwc Structure• . in Polut Otbil.’" Prweedings of thre Air For’e Grespykirs fitrano, W4r4 nop em Natural Charging of large Space Stru, ures...3, p. 1433- 1440, 1991. Bowman, C., Bogorad, A., Brucker, G., Seehra, S., and Lloyd, T., "ITO-Coated RF Transparent Materials for Antenna Sunscreen

  6. Unilateral CHARGE association

    NARCIS (Netherlands)

    Trip, J; van Stuijvenberg, M; Dikkers, FG; Pijnenburg, MWH

    A case with a predominantly unilateral CHARGE association is reported. The CHARGE association refers to a combination of congenital malformations. This boy had left-sided anomalies consisting of choanal atresia. coloboma and peripheral facial palsy. The infant had a frontal encephalocele. an anomaly

  7. Nondissipative optimum charge regulator

    Science.gov (United States)

    Rosen, R.; Vitebsky, J. N.

    1970-01-01

    Optimum charge regulator provides constant level charge/discharge control of storage batteries. Basic power transfer and control is performed by solar panel coupled to battery through power switching circuit. Optimum controller senses battery current and modifies duty cycle of switching circuit to maximize current available to battery.

  8. Charged corpuscular beam detector

    Energy Technology Data Exchange (ETDEWEB)

    Hikawa, H; Nishikawa, Y

    1970-09-29

    The present invention relates to a charged particle beam detector which prevents transient phenomena disturbing the path and focusing of a charged particle beam travelling through a mounted axle. The present invention provides a charged particle beam detector capable of decreasing its reaction to the charge in energy of the charged particle beam even if the relative angle between the mounted axle and the scanner is unstable. The detector is characterized by mounting electrically conductive metal pieces of high melting point onto the face of a stepped, heat-resistant electric insulating material such that the pieces partially overlap each other and individually provide electric signals, whereby the detector is no longer affected by the beam. The thickness of the metal piece is selected so that an eddy current is not induced therein by an incident beam, thus the incident beam is not affected. The detector is capable of detecting a misaligned beam since the metal pieces partially overlap each other.

  9. Role of molecular charge in nucleocytoplasmic transport.

    Directory of Open Access Journals (Sweden)

    Alexander Goryaynov

    Full Text Available Transport of genetic materials and proteins between the nucleus and cytoplasm of eukaryotic cells is mediated by nuclear pore complexes (NPCs. A selective barrier formed by phenylalanine-glycine (FG nucleoporins (Nups with net positive charges in the NPC allows for passive diffusion of signal-independent small molecules and transport-receptor facilitated translocation of signal-dependent cargo molecules. Recently, negative surface charge was postulated to be another essential criterion for selective passage through the NPC. However, the charge-driven mechanism in determining the transport kinetics and spatial transport route for either passive diffusion or facilitated translocation remains obscure. Here we employed high-speed single-molecule fluorescence microscopy with an unprecedented spatiotemporal resolution of 9 nm and 400 µs to uncover these mechanistic fundamentals for nuclear transport of charged substrates through native NPCs. We found that electrostatic interaction between negative surface charges on transiting molecules and the positively charged FG Nups, although enhancing their probability of binding to the NPC, never plays a dominant role in determining their nuclear transport mode or spatial transport route. A 3D reconstruction of transport routes revealed that small signal-dependent endogenous cargo protein constructs with high positive surface charges that are destined to the nucleus, rather than repelled from the NPC as suggested in previous models, passively diffused through an axial central channel of the NPC in the absence of transport receptors. Finally, we postulated a comprehensive map of interactions between transiting molecules and FG Nups during nucleocytoplasmic transport by combining the effects of molecular size, signal and surface charge.

  10. Optical Detection of Paraoxon Using Single-Walled Carbon Nanotube Films with Attached Organophosphorus Hydrolase-Expressed Escherichia coli

    Directory of Open Access Journals (Sweden)

    Intae Kim

    2015-05-01

    Full Text Available In whole-cell based biosensors, spectrophotometry is one of the most commonly used methods for detecting organophosphates due to its simplicity and reliability. The sensor performance is directly affected by the cell immobilization method because it determines the amount of cells, the mass transfer rate, and the stability. In this study, we demonstrated that our previously-reported microbe immobilization method, a microbe-attached single-walled carbon nanotube film, can be applied to whole-cell-based organophosphate sensors. This method has many advantages over other whole-cell organophosphate sensors, including high specific activity, quick cell immobilization, and excellent stability. A device with circular electrodes was fabricated for an enlarged cell-immobilization area. Escherichia coli expressing organophosphorus hydrolase in the periplasmic space and single-walled carbon nanotubes were attached to the device by our method. Paraoxon was hydrolyzed using this device, and detected by measuring the concentration of the enzymatic reaction product, p-nitrophenol. The specific activity of our device was calculated, and was shown to be over 2.5 times that reported previously for other whole-cell organophosphate sensors. Thus, this method for generation of whole-cell-based OP biosensors might be optimal, as it overcomes many of the caveats that prevent the widespread use of other such devices.

  11. Heat Release Property and Fire Performance of the Nomex/Cotton Blend Fabric Treated with a Nonformaldehyde Organophosphorus System

    Directory of Open Access Journals (Sweden)

    Charles Q. Yang

    2016-09-01

    Full Text Available Blending Nomex® with cotton improves its affordability and serviceability. Because cotton is a highly flammable fiber, Nomex®/cotton blend fabrics containing more than 20% cotton require flame-retardant treatment. In this research, combination of a hydroxyl functional organophosphorus oligmer (HFPO and 1,2,3,4-butanetetracarboxylic acid (BTCA was used for flame retardant finishing of the 65/35 Nomex®/cotton blend woven fabric. The system contains HFPO as a flame retardant, BTCA as a bonding agent, and triethenolamine (TEA as a reactive additive used to enhance the performance of HFPO/BTCA. Addition of TEA improves the hydrolysis resistance of the HFPO/BTCA crosslinked polymeric network on the blend fabric. Additionally, TEA enhances HFPO’s flame retardant performance by reducing formation of calcium salts and also by providing synergistic nitrogen to the treated blend fabric. The Nomex®/cotton blend fabric treated with the HFPO/BTCA/TEA system shows high flame resistance and high laundering durability at a relatively low HFPO concentration of 8% (w/w. The heat release properties of the treated Nomex®/cotton blend fabric were measured using microscale combustion calorimetry. The functions of BTCA; HFPO and TEA on the Nomex®/cotton blend fabric were elucidated based on the heat release properties, char formation, and fire performance of the treated blend fabric.

  12. Cytoplasmic vacuolation in cultured rat astrocytes induced by an organophosphorus agent requires extracellular signal-regulated kinase activation

    International Nuclear Information System (INIS)

    Isobe, Ichiro; Maeno, Yoshitaka; Nagao, Masataka; Iwasa, Mineo; Koyama, Hiroyoshi; Seko-Nakamura, Yoshimi; Monma-Ohtaki, Jun

    2003-01-01

    There are various toxic chemicals that cause cell death. However, in certain cases deleterious agents elicit various cellular responses prior to cell death. To determine the cellular mechanisms by which such cellular responses are induced is important, but sufficient attention has not been paid to this issue to date. In this study, we showed the characteristic effects of an organophosphorus (OP) agent, bis(pinacolyl methyl)phosphonate (BPMP), which we synthesized for the study of OP nerve agents, on cultured rat astrocytes. Morphologically, BPMP induced cytoplasmic vacuolation and stellation in the rat astrocytes. Cytoplasmic vacuolation is a cell pathological change observed, for example, in vacuolar degeneration, and stellation has been reported in astrocytic reactions against various stimuli. By pretreatment with cycloheximide, a protein synthesis inhibitor, stellation was inhibited, although vacuolation was not. Cell staining with a mitochondrion-selective dye indicated that the vacuolation probably occurs in the mitochondria that are swollen and vacuolatred in the center. Interestingly, the extracellular signal-regulated kinase (ERK) cascade inhibitor inhibited vacuolation and, to some extent, stellation. These results suggest that the ERK signaling cascade is important for the induction of mitochondrial vacuolation. We expect that a detailed study of these astrocytic reactions will provide us new perspectives regarding the variation and pathological significance of cell morphological changes, such as vacuolar degeneration, and also the mechanisms underlying various neurological disorders

  13. Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal

    Directory of Open Access Journals (Sweden)

    Muhammed Alamgir Zaman Chowdhury

    2014-01-01

    Full Text Available In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena (n=16, purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC, and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50% of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40–48%, 35–43%, and 30–45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85–90%, 80–91%, and 90–95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80–95% of some pesticides.

  14. A novel fluorimetric sensing platform for highly sensitive detection of organophosphorus pesticides by using egg white-encapsulated gold nanoclusters.

    Science.gov (United States)

    Yan, Xu; Li, Hongxia; Hu, Tianyu; Su, Xingguang

    2017-05-15

    Assays for organophosphorus pesticides (OPs) with high sensitivity as well as on-site screening have been urgently required to protect ecosystem and prevent disease. Herein, a novel fluorimetric sensing platform was constructed for quantitative detection of OPs via tyrosinase (TYR) enzyme-controlled quenching of gold nanoclusters (AuNCs). One-step green synthetic approach was developed for the synthesis of AuNCs by using chicken egg white (CEW) as template and stabilizer. Initially, TYR can catalyze the oxidation of dopamine to dopaminechrome, which can efficiently quench the fluorescence intensity of AuNCs at 630nm based on dynamic quenching process. However, with the presence of OPs, the activity of TYR was inhibited, resulting in the fluorescence recovery of AuNCs. This proposed fluorescence platform was demonstrated to enable rapid detection for OPs (paraoxon as model) and to provide excellent sensitivity with a detection limit of 0.1ngmL -1 . Significantly, the fluorescence probe was used to prepare paper-based test strips for visual detection of OPs, which validated the excellent potential for real-time and on-site application. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Optical detection of organophosphorus compounds based on Mn-doped ZnSe d-dot enzymatic catalytic sensor.

    Science.gov (United States)

    Gao, Xue; Tang, Guangchao; Su, Xingguang

    2012-01-01

    In this paper, we report a sensitive and selective method for detection of organophosphorus compounds (OPs) based on Mn:ZnSe d-dots-enzyme-hydrogen peroxide (H(2)O(2)) fluorescence quenching system. Acetylcholine esterase (AChE) can hydrolyze acetylcholine (ACh) to choline. Subsequently, choline oxidase (ChOx) oxidizes choline to generate H(2)O(2). The enzyme-generated H(2)O(2) can quench the fluorescence of Mn:ZnSe d-dots. When paraoxon are introduced in solution, it can interact with the active centers of AChE and decrease the enzyme activity. This leads to the decrease of the H(2)O(2) production and then the fluorescence quenching rate of Mn:ZnSe d-dots. Experimental results showed that the enzyme inhibition percentage of Mn:ZnSe d-dots-ChOx-AChE-ACh system was proportional to the logarithm of paraoxon in the range 4.84×10(-11) to 4.84×10(-6) mol/L with the detection limit (S/N=3) of 1.31×10(-11) mol/L. The proposed biosensor has been employed for quick determination of paraoxon in tap water and milk samples with satisfactory reproducibility and accuracy. This nano-biosensor was proved to be sensitive, rapid, simple and tolerance of most interfering substances. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Detection of residual organochlorine and organophosphorus pesticides in agricultural soil in Rio Verde region of San Luis Potosi, Mexico.

    Science.gov (United States)

    Velasco, Antonio; Hernández, Sergio; Ramírez, Martha; Ortíz, Irmene

    2014-01-01

    Organochlorine pesticides were intensively used in Mexico from 1950 until their ban and restriction in 1991. However, the presence of these compounds is commonly reported in many regions of the country. The aim of the present study was to identify and quantify residual organochlorine and organophosphorus pesticides in agricultural soil in Rio Verde region, San Luis Potosi state, which has been identified as possibly polluted by pesticides. Composed samples from 24 zones covering an area of approximately 5,440 ha were analyzed. The most frequently found pesticides were p,p'-DDT followed by ,p,p'-DDE, heptachlor, endosulfan and γ-HCH whose frequency rates were 100, 91, 83 and 54%, respectively. The concentration of p,p'-DDT in the crops grown in these soils was in the following order: chili > maize > tomato > alfalfa. The results obtained in this study show that p,p'-DDT values are lower or similar to those found in other agricultural regions of Mexico. Methyl and ethyl parathion were the most frequent organophosphate pesticide detected in 100% and 62.5% of the samples with average concentrations of 25.20 and 47.48 μg kg(-1), respectively. More research is needed to establish the background levels of pesticides in agricultural soils and their potential ecological and human health effects in this region.

  17. Matrix solid-phase dispersion extraction of organophosphorus pesticide using SiO2-poly(N-vinylimidazole)

    International Nuclear Information System (INIS)

    Gutiérrez-Solís, M C; Muñoz-Rodríguez, D; Carrera-Figueiras, C; Ávila-Ortega, A; Medina-Peralta, S

    2013-01-01

    A sorbent material based on silica particles modified with poly(N-vinylimidazole) (SiO 2 -PVI) has been evaluated for the treatment of samples by matrix solid-phase dispersion (MSPD). The extraction of four organophosphorus pesticides was done from a spiked tomato and the extracts were analyzed by gas chromatography coupled to mass spectrometry. Six elution solvents were evaluated and acetone was selected due to better recovery of the four pesticides and low background signal in the chromatograms. A factorial design 2 4 was used for selection of extraction conditions. The factors were contact time, acetone volume, treatment (with or without freeze-drying) and adsorbent (SiO 2 or SiO 2 -PVI). The best recoveries were obtained using 15 minutes of contact, 2 mL of solvent and sorbent without freeze-drying. The recoveries were between 60 and 83% for SiO 2 -PVI in spiked tomato with 0.2 and 0.8μg/g.

  18. De novo amplification within a silent human cholinesterase gene in a family subjected to prolonged exposure to organophosphorus insecticides

    International Nuclear Information System (INIS)

    Prody, C.A.; Dreyfus, P.; Soreq, H.; Zamir, R.; Zakut, H.

    1989-01-01

    A 100-fold DNA amplification in the CHE gene, coding for serum butyrylcholinesterase (BtChoEase), was found in a farmer expressing silent CHE phenotype. Individuals homozygous for this gene display a defective serum BtChoEase and are particularly vulnerable to poisoning by agricultural organophosphorus insecticides, to which all members of this family had long been exposed. DNA blot hybridization with regional BtChoEase cDNA probes suggested that the amplification was most intense in regions encoding central sequences within BtChoEase cDNA, whereas distal sequences were amplified to a much lower extent. This is in agreement with the onion skin model, based on amplification of genes in cultured cells and primary tumors. The amplification was absent in the grandparents but present at the same extent in one of their sons and in a grandson, with similar DNA blot hybridization patterns. In situ hybridization experiments localized the amplified sequences to the long arm of chromosome 3, close to the site where the authors previously mapped the CHE gene. Altogether, these observations suggest that the initial amplification event occurred early in embryogenesis, spermatogenesis, or oogenesis, where the CHE gene is intensely active and where cholinergic functioning was indicated to be physiologically necessary. These findings demonstrate a de novo amplification in apparently healthy individuals within an autosomal gene producing a target protein to an inhibitor

  19. Molecular characterization of the amplified carboxylesterase gene associated with organophosphorus insecticide resistance in the brown planthopper, Nilaparvata lugens.

    Science.gov (United States)

    Small, G J; Hemingway, J

    2000-12-01

    Widespread resistance to organophosphorus insecticides (OPs) in Nilaparvata lugens is associated with elevation of carboxylesterase activity. A cDNA encoding a carboxylesterase, Nl-EST1, has been isolated from an OP-resistant Sri Lankan strain of N. lugens. The full-length cDNA codes for a 547-amino acid protein with high homology to other esterases/lipases. Nl-EST1 has an N-terminal hydrophobic signal peptide sequence of 24 amino acids which suggests that the mature protein is secreted from cells expressing it. The nucleotide sequence of the homologue of Nl-EST1 in an OP-susceptible, low esterase Sri Lankan strain of N. lugens is identical to Nl-EST1. Southern analysis of genomic DNA from the Sri Lankan OP-resistant and susceptible strains suggests that Nl-EST1 is amplified in the resistant strain. Therefore, resistance to OPs in the Sri Lankan strain is through amplification of a gene identical to that found in the susceptible strain.

  20. Development of a passive air sampler to measure airborne organophosphorus pesticides and oxygen analogs in an agricultural community.

    Science.gov (United States)

    Armstrong, Jenna L; Yost, Michael G; Fenske, Richard A

    2014-09-01

    Organophosphorus pesticides are some of the most widely used insecticides in the US, and spray drift may result in human exposures. We investigate sampling methodologies using the polyurethane foam passive air sampling device to measure cumulative monthly airborne concentrations of OP pesticides chlorpyrifos, azinphos-methyl, and oxygen analogs. Passive sampling rates (m(3)d(-1)) were determined using calculations using chemical properties, loss of depuration compounds, and calibration with side-by-side active air sampling in a dynamic laboratory exposure chamber and in the field. The effects of temperature, relative humidity, and wind velocity on outdoor sampling rates were examined at 23 sites in Yakima Valley, Washington. Indoor sampling rates were significantly lower than outdoors. Outdoor rates significantly increased with average wind velocity, with high rates (>4m(3)d(-1)) observed above 8ms(-1). In exposure chamber studies, very little oxygen analog was observed on the PUF-PAS, yet substantial amounts chlorpyrifos-oxon and azinphos methyl oxon were measured in outdoor samples. PUF-PAS is a practical and useful alternative to AAS because it results in little artificial transformation to the oxygen analog during sampling, it provides cumulative exposure estimates, and the measured sampling rates were comparable to rates for other SVOCs. It is ideal for community based participatory research due to low subject burden and simple deployment in remote areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The structural requirements of organophosphorus insecticides (OPI) for reducing chicken embryo NAD(+) content in OPI-induced teratogenesis in chickens.

    Science.gov (United States)

    Seifert, Josef

    2016-05-01

    The objective of this study was to determine the structural requirements of organophosphorus insecticides (OPI) for reducing chicken embryo nicotinamide adenine dinucleotide (NAD(+)) content in OPI-induced teratogenesis and compare them with those needed for OPI inhibition of yolk sac membrane kynurenine formamidase (KFase), the proposed primary target for OPI teratogens in chicken embryos. The comparative molecular field analysis (COMFA) of three-dimensional quantitative structure-activity relationship (3D QSAR) revealed the electrostatic and steric fields as good predictors of OPI structural requirements to reduce NAD(+) content in chicken embryos. The dominant electrostatic interactions were localized at nitrogen-1, nitrogen-3, nitrogen of 2-amino substituent of the pyrimidinyl of pyrimidinyl phosphorothioates, and at the oxygen of crotonamide carbonyl in crotonamide phosphates. Bulkiness of the substituents at carbon-6 of the pyrimidinyls and/or N-substituents of crotonamides was the steric structural component that contributed to superiority of those OPI for reducing embryonic NAD(+) levels. Both electrostatic and steric requirements are similar to those defined in our previous study for OPI inhibition of chicken embryo yolk sac membrane KFase. The findings of this study provide another piece of evidence for the cause-and-effect relationship between yolk sac membrane KFase inhibition and reduced embryo NAD(+) content in NAD-associated OPI-induced teratogenesis in chickens. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Field studies on health effects from the application of two organophosphorus insecticide formulations by hand-held ULV to cotton.

    Science.gov (United States)

    Kummer, R; van Sittert, N J

    1986-10-01

    Two field studies to assess the health implications for farmers applying two different formulations containing organophosphorus (OP) pesticides to cotton by hand-held ULV are described. The first study, carried out in the Ivory Coast, involved the application of an endrin/DDT/methylparathion (MEP) formulation in an aromatic hydrocarbon solvent. The second study took place in Indonesia with a 20% monocrotophos formulation in a mixture of a glycol and a glycol ether. Both studies were carried out under actual field conditions. The purpose of the studies was to get a good assessment of the health hazards of the particular formulation, used under the specific circumstances and agronomic requirements of the area of application and taking into account all local, climatic and cultural conditions that could be of possible influence. The results showed that in both studies skin exposures took place during application and especially during handling, filling and cleaning, and that inhalation of spray mist was negligible. Absorption was confirmed by the presence in urine of metabolites of endrin and methylparathion in the Ivory Coast study, and of dimethyl phosphate in the Indonesia study. No clinical signs or symptoms of intoxication were discovered in either study, nor were inhibitions of cholinesterase (ChE) activity of health significance established under the conditions of the studies. In addition, various practical aspects such as choice of apparatus, of formulation, the application procedures etc. are discussed.

  3. Innovative approach for the electrochemical detection of non-electroactive organophosphorus pesticides using oxime as electroactive probe

    International Nuclear Information System (INIS)

    Dong, Jing; Hou, Juying; Jiang, Jianxia; Ai, Shiyun

    2015-01-01

    Highlights: • Novel approach for electrochemical detection of non-electroactive OPs was proposed. • PAM was used as electroactive probe for the first time. • The detection system displayed high sensitivity and promptness. • The developed sensor was used in real samples with satisfactory results. - Abstract: An innovative approach for sensitive and simple electrochemical detection of non-electroactive organophosphorus pesticides (OPs) was described in this report. The novel strategy emphasized the fabrication of an oxime-based sensor via attaching pralidoxime (PAM) on graphene quantum dots (GQDs) modified glassy carbon electrode. The introduction of GQDs significantly increased the effective electrode area, and then enlarged the immobilization quantity of PAM. Thus, the oxidation current of PAM was obviously increased. Relying on the nucleophilic substitution reaction between oxime and OPs, fenthion was detected using PAM as the electroactive probe. Under optimum conditions, the difference of oxidation current of PAM was proportional to fenthion concentration over the range from 1.0 × 10 −11 M to 5.0 × 10 −7 M with a detection limit of 6.8 × 10 −12 M (S/N = 3). Moreover, the favorable detection performance in water and soil samples heralded the promising applications in on-site OPs detection

  4. Application of Box-Behnken design for the removal of two organophosphorus pesticides by used Tea leaves

    Science.gov (United States)

    Albanis, Triantafyllos; Valileios, Sakkas; Islam, Azharul M.

    2016-04-01

    Removal of two organophosphorus pesticides bromophos methyl [BM: O, O- dimethyl - O - (2, 5-dichloro -4 bromophenyl) phosphorothioate] and quinalphos [QP: O, O-diethyl O-2-quinoxalinyl phosphorothioate] on used tea leaves were studied by batch equilibration method. Adsorption isotherms were conformed well to Langmuir for quinalphos and Freundlich equation for bromophos methyl. The kinetic data fitted well by the pseudo second order model for both pesticides. Box-Behnken design was successfully employed for experimental design and analysis of results. The interactions of pH, initial concentration and adsorbent dose on two pesticides adsorption by used tea leaves were investigated by this model. The optimum pH, initial concentration and adsorbent dose with their corresponding removal efficiency were found to be 7.88, 11.94 mg L-1, 0.37g and 100% for bromophos methyl respectively, for quinalphos 8.72, 6.44 mg L-1, 0.39g and 93.98% respectively. Keywords: Box-Behnken; quinalphos; bromophos methyl; Kinetics; used tea leaves

  5. Study of Doubly Charged Delta Baryons in Collisions of Copper Nuclei at the Relativistic Heavy Ion Collider

    Science.gov (United States)

    2017-05-22

    connecting the three quarks. Composite particles composed of partons are known as “hadrons” and must have a neutral color charge. There are six... neutral charge of neutrons. The up quark has positive charge equivalent to two-thirds the charge of an electron, and the down quark has negative...known as “heavy ions.” An ion is an atom or molecule with net electric charge, bare nuclei have a large positive charge due to the absence of

  6. Clinical physics for charged particle treatment planning

    International Nuclear Information System (INIS)

    Chen, G.T.Y.; Pitluck, S.; Lyman, J.T.

    1981-01-01

    The installation of a computerized tomography (CT) scanner which can be used with the patient in an upright position is described. This technique will enhance precise location of tumor position relative to critical structures for accurate charged particle dose delivery during fixed horizontal beam radiotherapy. Pixel-by-pixel treatment planning programs have been developed to calculate the dose distribution from multi-port charged particle beams. The plan includes CT scans, data interpretation, and dose calculations. The treatment planning computer is discussed. Treatment planning for irradiation of ocular melanomas is described

  7. Charging equipment. Ladegeraet

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, E

    1981-09-17

    The invention refers to a charging equipment, particularly on board charging equipment for charging traction batteries of an electric vehicle from the AC mains supply, consisting of a DC converter, which contains a controlled power transistor, a switching off unloading circuit and a power transmitter, where the secondary winding is connected in series with a rectifier diode, and a smoothing capacitor is connected in parallel with this series circuit. A converter module is provided, which consists of two DC voltage converters, whose power transistors are controlled by a control circuit in opposition with a phase displacement of 180/sup 0/.

  8. Position Information

    Data.gov (United States)

    Social Security Administration — The Position Information Data Asset provides the ability to search for active SSA position descriptions using various search criteria. An individual may search by PD...

  9. Electrostatic charges generated on aerosolisation of dispersions

    International Nuclear Information System (INIS)

    Wang, Yanyang

    2001-01-01

    In responding to the international community's agreement of phasing out chlorofluorocarbon (CFC) propellants by the year 2000, hydrofluoroalkane (HFA) has been chosen to replace CFCs. Intensive investigations related to the new propellant products have been carried out. Aerosol electrostatics is one of the topics investigated. To understand and subsequently control the charging processes is the motive of the research reported here. To help elucidate the complex charging process occurring naturally during atomization of liquids from pressurised Metered Dose Inhalers (pMDIs), it has been broken down into a sequence of related, simpler sub processes-drop charging, streaming current charging (coarse spray), splashing charging and fine spray charging. Our initial studies are of single drops forming at and breaking away from the tips of capillary tubes. The drop forming processes are so slow that any hydrodynamic effect can be dismissed. Then the charge on the drop is measured. It is found that the charge on water drops is always negative (∼ 10 -14 C) at field-free condition and the magnitude of the charge increases as the drop size increases and the surrounding tube diameter decreases. With salt solutions, the charge on drops is negative at dilute solutions, decreases in magnitude as the concentration of electrolytes increases and finally reverses the sign of charge at approximately 1 M - drop charge becomes positive. All these experimental results can be explained in terms of contact potential between liquid and the inner wall of the capillary, which sets up an electric field between the pendant drop and the surrounding tube. Then computational simulation work is carried out and the data are compared with experimental results. It is found that the computer simulation data are in accord with experimental observations. This is a potential method to measure absolute potential difference between a liquid and a solid. Secondly, the hydrodynamic processes are investigated

  10. Dynamical charge fluctuation at FAIR energy

    International Nuclear Information System (INIS)

    Ghosh, Somnath; Mukhopadhyay, Amitabha

    2015-01-01

    The Compressed Baryonic Matter (CBM) experiment to be held at the Facility for antiproton and ion research (FAIR) is being designed to investigate the baryonic matter under extreme thermodynamic conditions. The hot and dense matter produced in this experiment will be rich in baryon number. It would be worthwhile to examine how the signatures proposed for identifying and characterizing a baryon free QGP like state behave in a baryon rich environment. Event-by-event fluctuation of net electrical charge and/or baryon number is one such indicator of the formation of the QGP, used and tested in RHIC and LHC heavy-ion experiments. One starts by defining the net charge Q = (N + - N - ) and the total charge N ch = (N + + N - ) where the quantities N + and N - are respectively, the multiplicities of positively and negatively charged particles

  11. Positive Psychology

    Science.gov (United States)

    Peterson, Christopher

    2009-01-01

    Positive psychology is a deliberate correction to the focus of psychology on problems. Positive psychology does not deny the difficulties that people may experience but does suggest that sole attention to disorder leads to an incomplete view of the human condition. Positive psychologists concern themselves with four major topics: (1) positive…

  12. Pion double charge exchange

    International Nuclear Information System (INIS)

    Cooper, M.D.

    1978-01-01

    The pion double charge exchange data on the oxygen isotopes is reviewed and new data on 9 Be, 12 C, 24 Mg, and 28 Si are presented. Where theoretical calculations exist, they are compared to the data. 9 references

  13. Water Quality Protection Charges

    Data.gov (United States)

    Montgomery County of Maryland — The Water Quality Protection Charge (WQPC) is a line item on your property tax bill. WQPC funds many of the County's clean water initiatives including: • Restoration...

  14. EV Charging Infrastructure Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Karner, Donald [Electric Transportation Inc., Rogers, AR (United States); Garetson, Thomas [Electric Transportation Inc., Rogers, AR (United States); Francfort, Jim [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    As highlighted in the U.S. Department of Energy’s EV Everywhere Grand Challenge, vehicle technology is advancing toward an objective to “… produce plug-in electric vehicles that are as affordable and convenient for the average American family as today’s gasoline-powered vehicles …” [1] by developing more efficient drivetrains, greater battery energy storage per dollar, and lighter-weight vehicle components and construction. With this technology advancement and improved vehicle performance, the objective for charging infrastructure is to promote vehicle adoption and maximize the number of electric miles driven. The EV Everywhere Charging Infrastructure Roadmap (hereafter referred to as Roadmap) looks forward and assumes that the technical challenges and vehicle performance improvements set forth in the EV Everywhere Grand Challenge will be met. The Roadmap identifies and prioritizes deployment of charging infrastructure in support of this charging infrastructure objective for the EV Everywhere Grand Challenge

  15. Space-Charge Effect

    International Nuclear Information System (INIS)

    Chauvin, N

    2013-01-01

    First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented. (author)

  16. Space-Charge Effect

    CERN Document Server

    Chauvin, N.

    2013-12-16

    First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented.

  17. EV Charging Infrastructure Roadmap

    International Nuclear Information System (INIS)

    Karner, Donald; Garetson, Thomas; Francfort, Jim

    2016-01-01

    As highlighted in the U.S. Department of Energy's EV Everywhere Grand Challenge, vehicle technology is advancing toward an objective to ''... produce plug-in electric vehicles that are as affordable and convenient for the average American family as today's gasoline-powered vehicles ...'' [1] by developing more efficient drivetrains, greater battery energy storage per dollar, and lighter-weight vehicle components and construction. With this technology advancement and improved vehicle performance, the objective for charging infrastructure is to promote vehicle adoption and maximize the number of electric miles driven. The EV Everywhere Charging Infrastructure Roadmap (hereafter referred to as Roadmap) looks forward and assumes that the technical challenges and vehicle performance improvements set forth in the EV Everywhere Grand Challenge will be met. The Roadmap identifies and prioritizes deployment of charging infrastructure in support of this charging infrastructure objective for the EV Everywhere Grand Challenge

  18. Charged weak currents

    International Nuclear Information System (INIS)

    Turlay, R.

    1979-01-01

    In this review of charged weak currents I shall concentrate on inclusive high energy neutrino physics. There are surely still things to learn from the low energy weak interaction but I will not discuss it here. Furthermore B. Tallini will discuss the hadronic final state of neutrino interactions. Since the Tokyo conference a few experimental results have appeared on charged current interaction, I will present them and will also comment on important topics which have been published during the last past year. (orig.)

  19. Relativistic charged Bose gas

    International Nuclear Information System (INIS)

    Hines, D.F.; Frankel, N.E.

    1979-01-01

    The charged Bose has been previously studied as a many body problem of great intrinsic interest which can also serve as a model of some real physical systems, for example, superconductors, white dwarf stars and neutron stars. In this article the excitation spectrum of a relativistic spin-zero charged Bose gas is obtained in a dielectric response formulation. Relativity introduces a dip in the spectrum and consequences of this dip for the thermodynamic functions are discussed

  20. Ubiquitous positioning

    CERN Document Server

    Mannings, Robin

    2008-01-01

    This groundbreaking resource offers a practical, in-depth understanding of Ubiquitous Positioning - positioning systems that identify the location and position of people, vehicles and objects in time and space in the digitized networked economy. The future and growth of ubiquitous positioning will be fueled by the convergence of many other areas of technology, from mobile telematics, Internet technology, and location systems, to sensing systems, geographic information systems, and the semantic web. This first-of-its-kind volume explores ubiquitous positioning from a convergence perspective, of

  1. N.M.R. study of organo-phosphorus compounds: non equivalence of methylenic protons in the {alpha} position of an asymmetric phosphorus atom. Application to study of coupling constants J{sub P,H} and J{sub H,H}; R.M.N. de composes organo-phosphores: non equivalence de protons methyleniques en {alpha} d'un phosphore asymetrique. Application a l'etude des constantes de couplage J{sub P,H} et J{sub H,H}

    Energy Technology Data Exchange (ETDEWEB)

    Albrand, J P [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    Non-equivalent methylenic protons, with respect to an asymmetric center, have been observed in the n.m.r. spectra of some three- and tetra-coordinated phosphorus compounds. The analysis of these spectra yield the following results: in the studied secondary phosphines, the inversion rate at the phosphorus atom is slow on the n.m.r. time scale; the geminal coupling constant, for a free-rotating methylene group attached to a phosphorus atom, is negative; in phosphines the non equivalence of methylenic protons reveals two {sup 2}J{sub P-C-H} coupling constants which differ by about 5 Hz. This result is in agreement with previous studies on cyclic phosphines. In phosphine oxides, the {sup 2}J{sub P-C-H} values are negative. The {sup 3}J{sub H-P-C-H} coupling constant is positive in both phosphines and phosphine oxides. In phosphines, the non-equivalent methylenic protons exhibit two nearly equal values for this coupling constant. (author) [French] La non-equivalence de protons methyleniques observee dans quelques composes phosphores tricoordines et tetracoordines a apporte les resultats suivants, concernant la stereochimie et les constantes de couplage dans ces composes: dans les phosphines secondaires, la structure pyramidale des liaisons issues du phosphore est fixe a l'echelle de temps de mesure de la R.M.N.; la constante de couplage {sup 2}J{sub H-C-H}, pour un methylene en libre rotation en {alpha} d'un atome de phosphore, est negative; dans les phosphines etudiees, la non-equivalence. observee pour les protons methyleniques s'accompagne d'une difference importante (5 Hz) entre les deux constantes de couplage {sup 2}J{sub P-C-H} determinees par l'analyse; ce resultat est en accord avec la stereospecificite deja observee pour ce couplage dans les phosphines cycliques. Les valeurs observees pour {sup 2}J{sub P-C-H} dans les oxydes de phosphines sont negatives. Les valeurs de la constante de couplage {sup 3}J{sub H-P-C-H}, dans les phosphines et oxydes de phosphine

  2. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-08-01

    Full Text Available The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4 x(HSO4 x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4 (H2SO4 x] clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition

  3. Positioning consumption

    DEFF Research Database (Denmark)

    Halkier, Bente; Keller, Margit

    2014-01-01

    positionings emerges based on empirical examples of research in parent–children consumption. Positionings are flexible discursive fixations of the relationship between the performances of the practitioner, other practitioners, media discourse and consumption activities. The basic positioning types...... are the practice maintenance and the practice change position, with different sorts of adapting in between. Media discourse can become a resource for a resistant position against social control or for an appropriating position in favour of space for action. Regardless of the current relation to a particular media......This article analyses the ways in which media discourses become a part of contested consumption activities. We apply a positioning perspective with practice theory to focus on how practitioners relate to media discourse as a symbolic resource in their everyday practices. A typology of performance...

  4. MOSFET Electric-Charge Sensor

    Science.gov (United States)

    Robinson, Paul A., Jr.

    1988-01-01

    Charged-particle probe compact and consumes little power. Proposed modification enables metal oxide/semiconductor field-effect transistor (MOSFET) to act as detector of static electric charges or energetic charged particles. Thickened gate insulation acts as control structure. During measurements metal gate allowed to "float" to potential of charge accumulated in insulation. Stack of modified MOSFET'S constitutes detector of energetic charged particles. Each gate "floats" to potential induced by charged-particle beam penetrating its layer.

  5. RESEARCH ON ENVIRONMENTAL CONTAMINATION IN RAW MILK IN TURIN DEPARTEMENT : HEAVY METALS, P.C.B, ORGANOCHLORINE AND ORGANOPHOSPHORUS PESTICIDES – YEARS 2005 – 2008

    Directory of Open Access Journals (Sweden)

    S. Cavallera

    2013-02-01

    Full Text Available In the period between 2005 and 2008 was carried out a survey on 252 samples of raw bovine milk collected in Turin departement to certain levels of contamination by heavy metals (Cd, Cr, Fe, Hg, Pb, Zn, PCB and organophosphorus and organochlorine pesticides. These results argue that the levels of heavy metals, PCB and pesticides are well below what is expected by the European legislation and that the situation is under control and that raw milk meets the hygiene requirements for human health.

  6. Activity of Ca(2+,Mg(2+-ATPase of sarcoplasmic reticulum and contraction strength of the frog skeletal muscles under the effect of organophosphorus insecticides

    Directory of Open Access Journals (Sweden)

    D. M. Nozdrenko

    2015-08-01

    Full Text Available The results of an experimental study of organo­phosphorus insecticides, including pirimiphosmethyl, diazinon and chlorpyrifos caused a decline of the contraction properties in m. tibialis anterior fiber bundles of Rana temporaria, as well as sarcoplasmic reticulum Ca2+,Mg2+-ATPase enzymatic activity reduction are outlined in this paper. Concentration-dependent strengths response diminishing in isolated skeletal muscle fiber bundles as a result of non-cholinergic influence of organophosphorus insecticides were found. A decrease of Ca2+,Mg2+-ATPase enzymatic activity in sarcoplasmic reticulum was observed after administration of each insecticide. The most significant inhibition of this enzyme was observed when using chlorpyrifos.

  7. Recovery evaluation of organophosphorus pesticides from bee pollen by matrix solid-phase dispersion extraction using sorbents based on silica and titania

    International Nuclear Information System (INIS)

    Torres-Perea, C; Muñoz-Rodríguez, D; Carrera-Figueiras, C; Medina-Peralta, S; Moguel-Ordóñez, Y B

    2013-01-01

    This work focused on the evaluation of the recovery of organophosphorus pesticides from bee pollen after matrix solid phase-dispersion extraction (MSPD). Materials based on silica, titania and titania modified with polivylnylimidazole or polyestirene were used as adsorbents for the extraction of pesticides. Small amounts of fortified pollen (0.1 g, at 1 micro-g/g of pesticides), adsorbent (0.4 g) and solvent elution (1 mL de acetonitrile – ACN) were used in the extractions. For recovery evaluation, pollen extracts were analyzed by gas chromatography coupled with mass spectrometry.

  8. [COMPARATIVE SENSITIVITY OF CHOLINESTERASES IN VERTEBRATES AND INVERTEBRATES TO HIGHLY SPECIFIC ORGANOPHOSPHORUS INHIBITORS DIISOPROPYL FLUOROPHOSPHATE (DFP) AND (2-ETHOXYMETHYL PHOSPHORYL THIOETHYL) ETHYL (METHYL) SULPHONIUM SULPHOMETHYLAT (GD-42)].

    Science.gov (United States)

    Basova, N E; Kormilitsyn, B N; Perchenok, A Yu; Rozengart, E V; Saakov, V S; Suvorov, A A

    2015-01-01

    The review presents data on comparative reactivity of 68 cholinesterase preparation from various organs and tissues in a number of vertebrates and invertebrates based on sensitivity to two highly specific and most studied organophosphorus inhibitors--diisopropyl fluorophosphates (DFP) and (2-ethoxymethyl phosphoryl thioethyl) ethyl (methyl) sulphonium sulphomethylat (GD-42). Analysis of these data suggests a great diversity in enzymologic characteristics of cholinesterase preparation in representatives of vertebrates and invertebrates, this variety observed even for closely related enzymes in animals of almost the same level of development.

  9. A Study of Electrostatic Charge on Insulating Film by Electrostatic Force Microscopy

    International Nuclear Information System (INIS)

    Kikunaga, K; Toosaka, K; Kamohara, T; Sakai, K; Nonaka, K

    2011-01-01

    Electrostatic charge properties on polypropylene film have been characterized by atomic force microscopy and electrostatic force microscopy. The measurements have been carried out after the polypropylene film was electrified by contact and separation process in an atmosphere of controlled humidity. The negative and positive charge in concave surface has been observed. The correlation between concave surface and charge position suggests that the electrostatic charges could be caused by localized contact. On the other hand, positive charge on a flat surface has been observed. The absence of a relationship between surface profile and charge position suggests that the electrostatic charge should be caused by discharge during the separation process. The spatial migration of other positive charges through surface roughness has been observed. The results suggest that there could be some electron traps on the surface roughness and some potentials on the polypropylene film.

  10. Radiation by moving charges

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2017-04-15

    It is generally accepted that in order to describe the dynamics of relativistic particles in the laboratory (lab) frame it is sufficient to take into account the relativistic dependence of the particle momenta on the velocity. This solution of the dynamics problem in the lab frame makes no reference to Lorentz transformations. For this reason they are not discussed in particle tracking calculations in accelerator and plasma physics. It is generally believed that the electrodynamics problem can be treated within the same ''single inertial frame'' description without reference to Lorentz transformations. In particular, in order to evaluate radiation fields arising from charged particles in motion we need to know their velocities and positions as a function of the lab frame time t. The relativistic motion of a particle in the lab frame is described by Newton's second law ''corrected'' for the relativistic dependence of momentum on velocity. It is assumed in all standard derivations that one can perform identification of the trajectories in the source part of the usual Maxwell's equations with the trajectories vector x(t) measured (or calculated by using the corrected Newton's second law) in the lab frame. This way of coupling fields and particles is considered since more than a century as the relativistically correct procedure.We argue that this procedure needs to be changed, and we demonstrate the following, completely counterintuitive statement: the results of conventional theory of radiation by relativistically moving charges are not consistent with the principle of relativity. In order to find the trajectory of a particle in the lab frame consistent with the usual Maxwell's equations, one needs to solve the dynamic equation inmanifestly covariant form by using the coordinate-independent proper time τ to parameterize the particle world-line in space-time. We show that there is a difference between &apos

  11. Angular momentum of an electric charge and magnetically charged black hole

    Energy Technology Data Exchange (ETDEWEB)

    Garfinkle, D. (California Univ., Santa Barbara (USA). Dept. of Physics); Rey, S.J. (California Univ., Santa Barbara (USA). Dept. of Physics Florida Univ., Gainesville, FL (USA). Inst. for Fundamental Theory)

    1991-03-21

    We find the angular momentum L of a point particle with electric charge e held at a fixed position in the presence of a black hole with magnetic charge g. (For a point charge in the presence of an ordinary magnetic monopole, it is known that L=eg.) The angular momentum does depend on the separation distance between the particle and the black hole; however, L->eg for a large separation. Implications for the cosmic censorship hypothesis, the quantum hairs and other physical situations are discussed. (orig.).

  12. Angular momentum of an electric charge and magnetically charged black hole

    International Nuclear Information System (INIS)

    Garfinkle, D.; Rey, Soo-Jong

    1990-01-01

    We find the angular momentum L of a point particle with electric charge e held at a fixed position in the presence of a black hole with magnetic charge g. (For a point charge in the presence of an of ordinary magnetic monopole, it is known that L = eg). The angular momentum does depend on the separation distance between the particle and the black hole; however, L → eg for a large separation. Implications for the cosmic censorship hypothesis, the quantum hairs and other physical situations are discussed

  13. Uncharged positive electrode composition

    Science.gov (United States)

    Kaun, Thomas D.; Vissers, Donald R.; Shimotake, Hiroshi

    1977-03-08

    An uncharged positive-electrode composition contains particulate lithium sulfide, another alkali metal or alkaline earth metal compound other than sulfide, e.g., lithium carbide, and a transition metal powder. The composition along with a binder, such as electrolytic salt or a thermosetting resin is applied onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within an electrochemical cell opposite to a negative electrode containing a material such as aluminum or silicon for alloying with lithium. During charging, lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode. Excess negative electrode capacity over that from the transition metal sulfide is provided due to the electrochemical reaction of the other than sulfide alkali metal or alkaline earth metal compound.

  14. Magnetic confinement system using charged ammonia targets

    International Nuclear Information System (INIS)

    Porter, G.D.; Bogdanoff, A.

    1979-01-01

    A system is described for guiding charged laser targets to a predetermined focal spot of a laser along generally arbitrary, and especially horizontal, directions which comprises a series of electrostatic sensors which provide inputs to a computer for real time calculation of position, velocity, and direction of the target along an initial injection trajectory

  15. Probabilistic acute risk assessment of cumulative exposure to organophosphorus and carbamate pesticides from dietary vegetables and fruits in Shanghai populations.

    Science.gov (United States)

    Li, Fan; Yuan, Yaqun; Meng, Pai; Wu, Min; Li, Shuguang; Chen, Bo

    2017-05-01

    Organophosphorus pesticides (OPs) and carbamate pesticides (CPs) are among the most widely used pesticides in China, playing a major role in protecting agricultural commodities. In this study, we determined the cumulative acute exposure to OPs and CPs of Shanghai residents from vegetables and fruits (VFs). The food consumption data were obtained from the Shanghai Food Consumption Survey (SHFCS) of 2012-14 including a total of 1973 participants aged 2-90 years. The pesticide residue data were obtained from the Shanghai monitoring programme during 2008-11 with 34 organophosphates and 11 carbamates analysed in a total of 5335 samples of VFs. A probabilistic approach was performed as recommended by the EFSA, using the optimistic model with non-detects set as zero and with processing factors (PFs) being used and the pessimistic model with non-detects replaced by limit of detection (LOD) and without PFs. We used the relative potency factor (RPF) method to normalise the various pesticides to the index compound (IC) of methamidophos and chlorpyrifos separately. Only in the pessimistic model using methamidophos as the IC was there was small risk of exposure exceeding the ARfD (3 µg kg - 1 bw day - 1 ) in the populations of preschool children (0.029%), school-age children (0.022%) and adults (0.002%). There were no risk of exposure exceeding the ARfD of methamidophos in the optimistic model and of chlorpyrifos (100 µg kg - 1 bw day - 1 ) in both optimistic and pessimistic models in all three populations. Considering the Chinese habits of overwhelmingly eating processed food (vegetables being cooked, and fruits being washed or peeled), we conclude that little acute risk was found for the exposure to VF-sourced OPs and CPs in Shanghai.

  16. Exposure assessment of organophosphorus and organobromine flame retardants via indoor dust from elementary schools and domestic houses.

    Science.gov (United States)

    Mizouchi, Shigekazu; Ichiba, Masayoshi; Takigami, Hidetaka; Kajiwara, Natsuko; Takamuku, Toshiyuki; Miyajima, Toru; Kodama, Hiroki; Someya, Takashi; Ueno, Daisuke

    2015-03-01

    To assess the exposure of flame retardants (FRs) for school-children, organophosphorus flame retardants and plasticizers (PFRs) and organobromine flame retardants (BFRs) were determined in the indoor dust samples collected from elementary schools and domestic houses in Japan in 2009 and 2010. PFRs were detected in all the dust samples analyzed and the highest concentration of total PFRs was thousand-fold higher than that of BFRs. Among the PFRs, tris(butoxyethyl)phosphate (TBOEP) showed the highest concentration with a median (med.) of 270,000 ng g(-1) dry weight (3700-5,500,000 ng g(-1) dry weight), followed by tris(methylphenyl)phosphate (TMPPs)>triphenyl phosphate (TPHP)=tris(1,3-dichloro-2-propyl)phosphate (TDCIPP)=tris(2-chloroisopropyl)phosphate (TCIPP)=tris(2chloroethyl)phosphate (TCEP)>ethylhexyl diphenyl phosphate (EHDPP). Significantly higher concentrations of TBOEP, tri-n-butyl phosphate (TNBP), TPHP, TMPPs, and total-PFRs were found in dust samples from elementary schools than from domestic houses. It might be due to that higher concentrations of TBOEP (as leveling agent) were detected from the floor polisher/wax products collected in those elementary schools. On the other hand, significantly higher concentrations of TCEP, TCIPPs, and total chloroalkyl-PFRs were found in domestic houses than in elementary schools. Exposure assessments of PFRs via indoor dust from elementary schools and domestic houses were conducted by calculating the hazard quotient (HQ). Among PFRs, HQs for TBOEP exceeded 1 (higher than reference dose: RfD) and its highest value was 1.9. To reduce the intake of TBOEP by school-children, it is recommended that the use of floor polisher/wax containing TBOEP be reduced in schools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Determination of organophosphorus pesticides by dispersive liquid-liquid micro extraction coupled with gas chromatography-electron capture detection

    International Nuclear Information System (INIS)

    Mohd Marsin Sanagi; Siti Umairah Mokhtar; Mazidatul Akmam Miskam; Wan Aini Wan Ibrahim

    2011-01-01

    A simple, rapid and sensitive method termed as dispersive liquid-liquid micro extraction (DLLME) combined with gas chromatography-electron capture detector (GC-ECD) was developed for the determination of selected organophosphorus pesticides (OPPs) namely chloropyrifos, dimethoate and diazinon in water sample. In this method, a mixture of carbon disulfide, CS 2 (extraction solvent) and methanol (disperser solvent) was rapidly injected using syringe into the 5.00 mL water sample to form a cloudy solution where the OPPs were extracted into the fine droplets of extraction solvent. Upon centrifugation for 3 min at 3500 rpm, the fine droplets were sedimented at the bottom of the centrifuge tube. Sedimented phase (1 μL) was injected into the GC-ECD for separation and determination of OPPs. Important extraction parameters, such as type of disperser solvent, volume of extraction solvent and volume of disperser solvent were investigated. The optimized conditions for DLLME of the selected OPPs were methanol as disperser solvent, 30 μL of extraction solvent (CS 2 ) and 1.0 mL of disperser solvent (methanol). Under the optimum extraction conditions, the method showed good linearity in the range of 0.1 to 1.0 μg/ mL with correlation coefficient (r 2 ), in the range of 0.9976 to 0.9994 and low limits of detection (LOD) between 0.047 and 0.201 μg/ mL. The proposed method provided acceptable recoveries (72.67- 144 %) with good RSDs ranging from 2.74 % to 7.48 %. This method was successfully applied to the determination of OPPs in water samples obtained from a golf course and chloropyrifos and diazinon were detected at concentration 0.18 μg/ mL and 0.07 μg/ mL, respectively. (author)

  18. Galantamine counteracts development of learning impairment in guinea pigs exposed to the organophosphorus poison soman: Clinical significance

    Science.gov (United States)

    Mamczarz, Jacek; Kulkarni, Girish S.; Pereira, Edna F. R.; Albuquerque, Edson X.

    2017-01-01

    Galantamine, a drug used to treat Alzheimer’s disease, protects guinea pigs against the acute toxicity and lethality of organophosphorus (OP) compounds, including soman. Here, we tested the hypothesis that a single exposure of guinea pigs to 1xLD50 soman triggers cognitive impairments that can be counteracted by galantamine. Thus, animals were injected intramuscularly with saline (0.5 ml/kg) or galantamine (8 mg/kg) and 30 min later injected subcutaneously with soman (26.3 µg/kg) or saline. Cognitive performance was analyzed in the Morris water maze (MWM) four days or three months after the soman challenge. Fifty percent of the saline-injected animals that were challenged with soman survived with mild-to-moderate signs of acute toxicity that subsided within a few hours. These animals showed no learning impairment and no memory retention deficit, when training in the MWM started four days post-soman challenge. In contrast, animals presented significant learning impairment when testing started three months post-challenge. Though the magnitude of the impairment correlated with the severity of the acute toxicity, animals that presented no or only mild signs of toxicity were also learning impaired. All guinea pigs that were treated with galantamine survived the soman challenge with no signs of acute toxicity and learned the MWM task as control animals, regardless of when testing began. Galantamine also prevented memory extinction in both saline-and soman-challenged animals. In conclusion, learning impairment develops months after a single exposure to 1xLD50 soman, and galantamine prevents both the acute toxicity and the delayed cognitive deficits triggered by this OP poison. PMID:21784098

  19. An Innovative Rapid Method for Analysis of 10 Organophosphorus Pesticide Residues in Wheat by HS-SPME-GC-FPD/MSD.

    Science.gov (United States)

    Du, Xin; Ren, YongLin; Beckett, Stephen J

    2016-01-01

    The rapid detection of pesticide residues in wheat has become a top food security priority. A solvent-free headspace solid-phase microextraction (HS-SPME) has been evaluated for rapid screening of organophosphorus pesticide (OPP) residues in wheat with high sensitivity. Individual wheat samples (1.7 g), spiked with 10 OPPs, were placed in a 4 mL sealed amber glass vial and heated at 60°C for 45 min. During this time, the OPP residues were extracted with a 50 μm/30 μm divinylbenzene (DVB)/carboxen (CAR)/plasma desorption mass spectroscopy polydimethylsiloxane (PDMS) fiber from the headspace above the sample. The fiber was then removed and injected into the GC injection port at 250°C for desorption of the extracted chemicals. The multiple residues were identified by a GC mass spectrometer detector (GC-MSD) and quantified with a GC flame photometric detector (GC-FPD). Seven spiked levels of 10 OPPs on wheat were analyzed. The GC responses for a 50 μm/30 μm DVB/CAR/PDMS fiber increased with increasing spiking levels, yielding significant (R(2) > 0.98) linear regressions. The lowest LODs of the multiple pesticide standards were evaluated under the conditions of the validation study in a range of levels from 0 (control) to 100 ng of pesticide residue per g of wheat that separated on a low-polar GC capillary column (Agilent DB-35UI). The results of the HS-SPME method were compared with the QuEChERS AOAC 2007.01 method and they showed several advantages over the latter. These included improved sensitivity, selectivity, and simplicity.

  20. Method development and validation for the simultaneous determination of organochlorine and organophosphorus pesticides in a complex sediment matrix.

    Science.gov (United States)

    Alcántara-Concepción, Victor; Cram, Silke; Gibson, Richard; Ponce de León, Claudia; Mazari-Hiriart, Marisa

    2013-01-01

    The Xochimilco area in the southeastern part of Mexico City has a variety of socioeconomic activities, such as periurban agriculture, which is of great importance in the Mexico City metropolitan area. Pesticides are used extensively, some being legal, mostly chlorpyrifos and malathion, and some illegal, mostly DDT. Sediments are a common sink for pesticides in aquatic systems near agricultural areas, and Xochimilco sediments have a complex composition with high contents of organic matter and clay that are ideal adsorption sites for organochlorine (OC) and organophosphorus (OP) pesticides. Therefore, it is important to have a quick, affordable, and reliable method to determine these pesticides. Conventional methods for the determination of OC and OP pesticides are long, laborious, and costly owing to the high volume of solvents and adsorbents. The present study developed and validated a method for determining 18 OC and five OP pesticides in sediments with high organic and clay contents. In contrast with other methods described in the literature, this method allows isolation of the 23 pesticides with a 12 min microwave-assisted extraction (MAE) and one-step cleanup of pesticides. The method developed is a simpler, time-saving procedure that uses only 3.5 g of dry sediment. The use of MAE eliminates excessive handling and the possible loss of analytes. It was shown that the use of LC-Si cartridges with hexane-ethyl acetate (75+25, v/v) in the cleanup procedure recovered all pesticides with rates between 70 and 120%. The validation parameters demonstrated good performance of the method, with intermediate precision ranging from 7.3 to 17.0%, HorRat indexes all below 0.5, and tests of accuracy with the 23 pesticides at three concentration levels demonstrating recoveries ranging from 74 to 114% and RSDs from 3.3 to 12.7%.

  1. Planarian cholinesterase: in vitro characterization of an evolutionarily ancient enzyme to study organophosphorus pesticide toxicity and reactivation.

    Science.gov (United States)

    Hagstrom, Danielle; Hirokawa, Hideto; Zhang, Limin; Radic, Zoran; Taylor, Palmer; Collins, Eva-Maria S

    2017-08-01

    The freshwater planarian Dugesia japonica has recently emerged as an animal model for developmental neurotoxicology and found to be sensitive to organophosphorus (OP) pesticides. While previous activity staining of D. japonica, which possess a discrete cholinergic nervous system, has shown acylthiocholine catalysis, it is unknown whether this is accomplished through an acetylcholinesterase (AChE), butyrylcholinesterase (BChE), or a hybrid esterase and how OP exposure affects esterase activity. Here, we show that the majority of D. japonica cholinesterase (DjChE) activity departs from conventional AChE and BChE classifications. Inhibition by classic protonable amine and quaternary reversible inhibitors (ethopropazine, donepezil, tacrine, edrophonium, BW284c51, propidium) shows that DjChE is far less sensitive to these inhibitors than human AChE, suggesting discrete differences in active center and peripheral site recognition and structures. Additionally, we find that different OPs (chlorpyrifos oxon, paraoxon, dichlorvos, diazinon oxon, malaoxon) and carbamylating agents (carbaryl, neostigmine, physostigmine, pyridostigmine) differentially inhibit DjChE activity in vitro. DjChE was most sensitive to diazinon oxon and neostigmine and least sensitive to malaoxon and carbaryl. Diazinon oxon-inhibited DjChE could be reactivated by the quaternary oxime, pralidoxime (2-PAM), and the zwitterionic oxime, RS194B, with RS194B being significantly more potent. Sodium fluoride (NaF) reactivates OP-DjChE faster than 2-PAM. As one of the most ancient true cholinesterases, DjChE provides insight into the evolution of a hybrid enzyme before the separation into distinct AChE and BChE enzymes found in higher vertebrates. The sensitivity of DjChE to OPs and capacity for reactivation validate the use of planarians for OP toxicology studies.

  2. A sensitive LC-MS/MS method for measurement of organophosphorus pesticides and their oxygen analogs in air sampling matrices.

    Science.gov (United States)

    Armstrong, Jenna L; Dills, Russell L; Yu, Jianbo; Yost, Michael G; Fenske, Richard A

    2014-01-01

    A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for determination of levels of the organophosphorus (OP) pesticides chlorpyrifos (CPF), azinphos methyl (AZM), and their oxygen analogs chlorpyrifos-oxon (CPF-O) and azinphos methyl-oxon (AZM-O) on common active air sampling matrices. XAD-2 resin and polyurethane foam (PUF) matrices were extracted with acetonitrile containing stable-isotope labeled internal standards (ISTD). Analysis was accomplished in Multiple Reaction Monitoring (MRM) mode, and analytes in unknown samples were identified by retention time (±0.1 min) and qualifier ratio (±30% absolute) as compared to the mean of calibrants. For all compounds, calibration linearity correlation coefficients were ≥0.996. Limits of detection (LOD) ranged from 0.15-1.1 ng/sample for CPF, CPF-O, AZM, and AZM-O on active sampling matrices. Spiked fortification recoveries were 78-113% from XAD-2 active air sampling tubes and 71-108% from PUF active air sampling tubes. Storage stability tests also yielded recoveries ranging from 74-94% after time periods ranging from 2-10 months. The results demonstrate that LC-MS/MS is a sensitive method for determining these compounds from two different matrices at the low concentrations that can result from spray drift and long range transport in non-target areas following agricultural applications. In an inter-laboratory comparison, the limit of quantification (LOQ) for LC-MS/MS was 100 times lower than a typical gas chromatography-mass spectrometry (GC-MS) method.

  3. A Disposable Organophosphorus Pesticides Enzyme Biosensor Based on Magnetic Composite Nano-Particles Modified Screen Printed Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Weigang Wen

    2010-01-01

    Full Text Available A disposable organophosphorus pesticides (OPs enzyme biosensor based on magnetic composite nanoparticle-modified screen printed carbon electrodes (SPCE has been developed. Firstly, an acetylcholinesterase (AChE-coated Fe3O4/Au (GMP magnetic nanoparticulate (GMP-AChE was synthesized. Then, GMP-AChE was absorbed on the surface of a SPCE modified by carbon nanotubes (CNTs/nano-ZrO2/prussian blue (PB/Nafion (Nf composite membrane by an external magnetic field. Thus, the biosensor (SPCE|CNTs/ZrO2/PB/Nf|GMP-AChE for OPs was fabricated. The surface of the biosensor was characterized by scanning electron micrography (SEM and X-ray fluorescence spectrometery (XRFS and its electrochemical properties were studied by cyclic voltammetry (CV and differential pulse voltammetry (DPV. The degree of inhibition (A% of the AChE by OPs was determined by measuring the reduction current of the PB generated by the AChE-catalyzed hydrolysis of acetylthiocholine (ATCh. In pH = 7.5 KNO3 solution, the A was related linearly to the concentration of dimethoate in the range from 1.0 × 10-3–10 ng•mL-1 with a detection limit of 5.6 × 10-4 ng•mL-1. The recovery rates in Chinese cabbage exhibited a range of 88%–105%. The results were consistent with the standard gas chromatography (GC method. Compared with other enzyme biosensors the proposed biosensor exhibited high sensitivity, good selectivity with disposable, low consumption of sample. In particular its surface can be easily renewed by removal of the magnet. The convenient, fast and sensitive voltammetric measurement opens new opportunities for OPs analysis.

  4. Synthesis and application of molecularly imprinted polymers for the selective extraction of organophosphorus pesticides from vegetable oils.

    Science.gov (United States)

    Boulanouar, Sara; Combès, Audrey; Mezzache, Sakina; Pichon, Valérie

    2017-09-01

    The increasing use of pesticides in agriculture causes environmental issues and possible serious health risks to humans and animals. Their determination at trace concentrations in vegetable oils constitutes a significant analytical challenge. Therefore, their analysis often requires both an extraction and a purification step prior to separation with liquid chromatography (LC) and mass spectrometry (MS) detection. This work aimed at developing sorbents that are able to selectively extract from vegetable oil samples several organophosphorus (OPs) pesticides presenting a wide range of physico-chemical properties. Therefore, different conditions were screened to prepare molecularly imprinted polymers (MIPs) by a non-covalent approach. The selectivity of the resulting polymers was evaluated by studying the OPs retention in pure media on both MIPs and non-imprinted polymers (NIP) used as control. The most promising MIP sorbent was obtained using monocrotophos (MCP) as the template, methacrylic acid (MAA) as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker with a molar ratio of 1/4/20 respectively. The repeatability of the extraction procedure and of the synthesis procedure was demonstrated in pure media. The capacity of this MIP was 1mg/g for malathion. This MIP was also able to selectively extract three OPs from almond oil by applying the optimized SPE procedure. Recoveries were between 73 and 99% with SD values between 4 and 6% in this oil sample. The calculated LOQs (between 0.3 and 2μg/kg) in almond seeds with a SD between 0.1 and 0.4μg/kg were lower than the Maximum Residue Levels (MRLs) established for the corresponding compounds in almond seed. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Multiwalled carbon nanotubes as solid-phase extraction materials for the gas chromatographic determination of organophosphorus pesticides in waters.

    Science.gov (United States)

    Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Angel Rodríguez-Delgado, Miguel

    2008-10-01

    In the present work, a GC method with nitrogen-phosphorus detection (NPD) was developed for the simultaneous determination of eight organophosphorus pesticide (OPP) residues (i.e., ethoprofos, diazinon, chlorpyrifos-methyl, fenitrothion, malathion, chlorpyrifos, fenamiphos, and buprofezin) in water samples. Preconcentration of the water samples was carried out using an SPE procedure with multiwalled carbon nanotubes (MWCNTs) of 10-15 nm od, 2-6 nm id, and 0.1-10 microm length as stationary phase. Extraction parameters, such as the amount of MWCNTs, sample volume, pH, and type and amount of the eluent were optimized. The most favorable conditions were as follows: 40 mg MWCNTs, 800 mL water, pH 6.0, and 20 mL dichloromethane, respectively. The MWCNTs-SPE-GC-NPD method was applied to the determination of these pesticides in real water samples: mineral and ground water as well as run-off water from an agricultural area collected shortly before opening out onto the sea. A recovery study was developed with five consecutive extractions of the three types of water spiked at three concentration levels (n = 15). Mean recovery values were in the range of 75-116% for mineral water (RSD water (RSD waters (RSDs waters, RSDs waters). The proposed method was also applied to the analysis of six water samples (two of each type: mineral, ground, and run-off waters) in which no residues of the selected pesticides were found. Results show that the MWCNTs used in this work have a high adsorbability of the pesticides under study. The main advantage of the use of these MWCNTs is their low cost when compared with those MWCNTs previously used in the literature and with conventional SPE cartridges.

  6. Organophosphorus insecticides chlorpyrifos and diazinon and oxidative stress in neuronal cells in a genetic model of glutathione deficiency

    International Nuclear Information System (INIS)

    Giordano, Gennaro; Afsharinejad, Zhara; Guizzetti, Marina; Vitalone, Annabella; Kavanagh, Terrance J.; Costa, Lucio G.

    2007-01-01

    Over the past several years evidence has been accumulating from in vivo animal studies, observations in humans, and in vitro studies, that organophosphorus (OP) insecticides may induce oxidative stress. Such effects may contribute to some of the toxic manifestations of OPs, particularly upon chronic or developmental exposures. The aim of this study was to investigate the role of oxidative stress in the neurotoxicity of two commonly used OPs, chlorpyrifos (CPF) and diazinon (DZ), their oxygen analogs (CPO and DZO), and their 'inactive' metabolites (TCP and IMP), in neuronal cells from a genetic model of glutathione deficiency. Cerebellar granule neurons from wild type mice (Gclm +/+) and mice lacking the modifier subunit of glutamate cysteine ligase (Gclm -/-), the first and limiting step in the synthesis of glutathione (GSH), were utilized. The latter display very low levels of GSH and are more susceptible to the toxicity of agents that increase oxidative stress. CPO and DZO were the most cytotoxic compounds, followed by CPF and DZ, while TCP and IMP displayed lower toxicity. Toxicity was significantly higher (10- to 25-fold) in neurons from Gclm (-/-) mice, and was antagonized by various antioxidants. Depletion of GSH from Gclm (+/+) neurons significantly increased their sensitivity to OP toxicity. OPs increased intracellular levels of reactive oxygen species and lipid peroxidation and in both cases the effects were greater in neurons from Gclm (-/-) mice. OPs did not alter intracellular levels of GSH, but significantly increased those of oxidized glutathione (GSSG). Cytotoxicity was not antagonized by cholinergic antagonists, but was decreased by the calcium chelator BAPTA-AM. These studies indicate that cytotoxicity of OPs involves generation of reactive oxygen species and is modulated by intracellular GSH, and suggest that it may involve disturbances in intracellular homeostasis of calcium

  7. Plasma esterases in the tegu lizard Tupinambis merianae (Reptilia, Teiidae): impact of developmental stage, sex, and organophosphorus in vitro exposure.

    Science.gov (United States)

    Basso, Agustín; Attademo, Andrés M; Lajmanovich, Rafael C; Peltzer, Paola M; Junges, Celina; Cabagna, Mariana C; Fiorenza, Gabriela S; Sanchez-Hernandez, Juan Carlos

    2012-01-01

    In this study, we determined normal serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) activities in Tupinambis merianae in order to obtain reference values for organophosphorus pesticide monitoring. Forty-two T. merianae individuals were grouped by sex and size to identify potential differences in their enzyme levels to allow for proper representation of normal values for females, males, juveniles, and hatchlings. Mean CbE was determined using two model substrates: alpha-naphtylacetate (α-NA) and p-nitrophenyl valerate (4-NPV). BChE and CbE sensitivity to malaoxon (Mx) was also evaluated as well as the possibility of BChE reactivation with pyridine-2-aldoxime methochloride (2-PAM). Mean adult females' BChE was significantly higher than adult males, juveniles, and hatchlings. No significant differences were found between groups regarding CbE. CbE (4-NPV) activity showed slightly negative correlation with lizard snout-vent length, while BChE and CbE (α-NA) showed no correlation with body size. Apparent IC(50) values for BChE and CbE (α-NA) suggested different sensitivities among groups. CbE (4-NPV) could not be inhibited. All Mx-inhibited groups treated with 2-PAM in a final concentration of 2.8 mM showed clear signs of reactivation. In conclusion, the results demonstrate that (1) plasma esterase activity did not vary with age and sex, except for BChE activity, and (2) because biological and environmental variables could be confounding factors in the response of plasma cholinesterases, complementary biomarkers like CbE inhibition and oxime-induced reactivation of esterases are strongly recommended.

  8. Organophosphorus pesticide residues in vegetables from farms, markets, and a supermarket around Kwan Phayao Lake of Northern Thailand.

    Science.gov (United States)

    Sapbamrer, Ratana; Hongsibsong, Surat

    2014-07-01

    This study investigated organophosphorus (OP) residues in vegetables from 27 farms, 106 markets, and 1 supermarket around Kwan Phayao Lake, Northern Thailand, between August and September 2013. Types of vegetables sampled were all vegetables cultivated or sold around the study site. The most common OP pesticides detected in farm samples were chlorpyrifos (50 %), malathion (31.8 %), monocrotophos (31.8 %), diazinon (13.6 %), omethoate (13.6 %), and dicrotophos (9.1 %). The most common OP pesticides detected in market samples were chlorpyrifos (33.9 %), diazinon (18.6 %), parathion-methyl (3.4 %), profenofos (3.4 %), primiphos-ethyl (3.4 %), and fenitrothion (1.7 %). The OP pesticides detected in supermarket samples were chlorpyrifos (33.3 %), and diazinon (66.7 %). Among the compounds detected, chlorpyrifos was detected in most of the vegetable samples from all sources. The highest chlorpyrifos level in farm samples were found in lemon balm (2.423 mg/kg) followed by Vietnamese coriander (0.835 mg/kg), and cowpea (0.027 mg/kg). The highest level in markets samples were found in garlic (7.785 mg/kg) followed by Chinese cabbage (2.864 mg/kg) and Vietnamese coriander (1.308 mg/kg). Residues from supermarket samples were found only in parsley (0.027 mg/kg). The findings showed that 16 samples (59.3 %) from farms and 14 samples (13.2 %) from markets contained OP residues at or above the maximum residue limits established by the European Union. It is concluded that awareness, safety education, and strict regulation of pesticide use are necessary.

  9. Proton conducting membranes prepared by incorporation of organophosphorus acids into alcohol barrier polymers for direct methanol fuel cells

    Science.gov (United States)

    Jiang, Zhongyi; Zheng, Xiaohong; Wu, Hong; Pan, Fusheng

    A novel type of DMFC membrane was developed via incorporation of organophosphorus acids (OPAs) into alcohol barrier materials (polyvinyl alcohol/chitosan, PVA/CS) to simultaneously acquire high proton conductivity and low methanol permeability. Three kinds of OPAs including amino trimethylene phosphonic acid (ATMP), ethylene diamine tetra(methylene phosphonic acid) (EDTMP) and hexamethylene diamine tetra(methylene phosphonic acid) (HDTMP), with different molecular structure and phosphonic acid groups content were added into PVA/CS blends and served the dual functions as proton conductor as well as crosslinker. The as-prepared OPA-doped PVA/CS membranes exhibited remarkably enhanced proton conducting ability, 2-4 times higher than that of the pristine PVA/CS membrane, comparable with that for Nafion ®117 membrane (5.04 × 10 -2 S cm -1). The highest proton conductivities 3.58 × 10 -2, 3.51 × 10 -2 and 2.61 × 10 -2 S cm -1 for ATMP-, EDTMP- and HDTMP-doped membranes, respectively were all achieved at highest initial OPA doping content (23.1 wt.%) at room temperature. The EDTMP-doped PVA/CS membrane with an acid content of 13.9 wt.% showed the lowest methanol permeability of 2.32 × 10 -7 cm 2 s -1 which was 16 times lower than that of Nafion ®117 membrane. In addition, the thermal stability and oxidative durability were both significantly improved by the incorporation of OPAs in comparison with pristine PVA/CS membranes.

  10. Proton conducting membranes prepared by incorporation of organophosphorus acids into alcohol barrier polymers for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhongyi; Zheng, Xiaohong; Wu, Hong; Pan, Fusheng [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2008-10-15

    A novel type of DMFC membrane was developed via incorporation of organophosphorus acids (OPAs) into alcohol barrier materials (polyvinyl alcohol/chitosan, PVA/CS) to simultaneously acquire high proton conductivity and low methanol permeability. Three kinds of OPAs including amino trimethylene phosphonic acid (ATMP), ethylene diamine tetra(methylene phosphonic acid) (EDTMP) and hexamethylene diamine tetra(methylene phosphonic acid) (HDTMP), with different molecular structure and phosphonic acid groups content were added into PVA/CS blends and served the dual functions as proton conductor as well as crosslinker. The as-prepared OPA-doped PVA/CS membranes exhibited remarkably enhanced proton conducting ability, 2-4 times higher than that of the pristine PVA/CS membrane, comparable with that for Nafion {sup registered} 117 membrane (5.04 x 10{sup -2} S cm{sup -1}). The highest proton conductivities 3.58 x 10{sup -2}, 3.51 x 10{sup -2} and 2.61 x 10{sup -2} S cm{sup -1} for ATMP-, EDTMP- and HDTMP-doped membranes, respectively were all achieved at highest initial OPA doping content (23.1 wt.%) at room temperature. The EDTMP-doped PVA/CS membrane with an acid content of 13.9 wt.% showed the lowest methanol permeability of 2.32 x 10{sup -7} cm{sup 2} s{sup -1} which was 16 times lower than that of Nafion {sup registered} 117 membrane. In addition, the thermal stability and oxidative durability were both significantly improved by the incorporation of OPAs in comparison with pristine PVA/CS membranes. (author)

  11. Resistance to organophosphorus agent toxicity in transgenic mice expressing the G117H mutant of human butyrylcholinesterase

    International Nuclear Information System (INIS)

    Wang Yuxia; Ticu Boeck, Andreea; Duysen, Ellen G.; Van Keuren, Margaret; Saunders, Thomas L.; Lockridge, Oksana

    2004-01-01

    Organophosphorus toxicants (OP) include chemical nerve agents and pesticides. The goal of this work was to find out whether an animal could be made resistant to OP toxicity by genetic engineering. The human butyrylcholinesterase (BChE) mutant G117H was chosen for study because it has the unusual ability to hydrolyze OP as well as acetylcholine, and it is resistant to inhibition by OP. Human G117H BChE, under the control of the ROSA26 promoter, was expressed in all tissues of transgenic mice. A stable transgenic mouse line expressed 0.5 μg/ml of human G117H BChE in plasma as well as 2 μg/ml of wild-type mouse BChE. Intestine, kidneys, stomach, lungs, heart, spleen, liver, brain, and muscle expressed 0.6-0.15 μg/g of G117H BChE. Transgenic mice were normal in behavior and fertility. The LD50 dose of echothiophate for wild-type mice was 0.1 mg/kg sc. This dose caused severe cholinergic signs of toxicity and lethality in wild-type mice, but caused no deaths and only mild toxicity in transgenic animals. The mechanism of protection was investigated by measuring acetylcholinesterase (AChE) and BChE activity. It was found that AChE and endogenous BChE were inhibited to the same extent in echothiophate-treated wild type and transgenic mice. This led to the hypothesis that protection against echothiophate toxicity was not explained by hydrolysis of echothiophate. In conclusion, the transgenic G117H BChE mouse demonstrates the factors required to achieve protection from OP toxicity in a vertebrate animal

  12. Polyacrylic acid-coated cerium oxide nanoparticles: An oxidase mimic applied for colorimetric assay to organophosphorus pesticides.

    Science.gov (United States)

    Zhang, Shi-Xiang; Xue, Shi-Fan; Deng, Jingjing; Zhang, Min; Shi, Guoyue; Zhou, Tianshu

    2016-11-15

    It is important and urgent to develop reliable and highly sensitive methods that can provide on-site and rapid detection of extensively used organophosphorus pesticides (OPs) for their neurotoxicity. In this study, we developed a novel colorimetric assay for the detection of OPs based on polyacrylic acid-coated cerium oxide nanoparticles (PAA-CeO2) as an oxidase mimic and OPs as inhibitors to suppress the activity of acetylcholinesterase (AChE). Firstly, highly dispersed PAA-CeO2 was prepared in aqueous solution, which could catalyze the oxidation of TMB to produce a color reaction from colorless to blue. And the enzyme of AChE was used to catalyze the substrate of acetylthiocholine (ATCh) to produce thiocholine (TCh). As a thiol-containing compound with reducibility, TCh can decrease the oxidation of TMB catalyzed by PAA-CeO2. Upon incubated with OPs, the enzymatic activity of AChE was inhibited to produce less TCh, resulting in more TMB catalytically oxidized by PAA-CeO2 to show an increasing blue color. The two representative OPs, dichlorvos and methyl-paraoxon, were tested using our proposed assay. The novel assay showed notable color change in a concentration-dependent manner, and as low as 8.62 ppb dichlorvos and 26.73 ppb methyl-paraoxon can be readily detected. Therefore, taking advantage of such oxidase-like activity of PAA-CeO2, our proposed colorimetric assay can potentially be a screening tool for the precise and rapid evaluation of the neurotoxicity of a wealth of OPs. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Biodegradation and bioremediation potential of diazinon-degrading Serratia marcescens to remove other organophosphorus pesticides from soils.

    Science.gov (United States)

    Cycoń, Mariusz; Żmijowska, Agnieszka; Wójcik, Marcin; Piotrowska-Seget, Zofia

    2013-03-15

    The ability of diazinon-degrading Serratia marcescens to remove organophosphorus pesticides (OPPs), i.e. chlorpyrifos (CP), fenitrothion (FT), and parathion (PT) was studied in a mineral salt medium (MSM) and in three soils of different characteristics. This strain was capable of using all insecticides at concentration of 50 mg/l as the only carbon source when grown in MSM, and 58.9%, 70.5%, and 82.5% of the initial dosage of CP, FT, and PT, respectively was degraded within 14 days. The biodegradation experiment showed that autochthonous microflora in all soils was characterized by a degradation potential of all tested OPPs; however, the initial lag phases for degradation of CP and FT, especially in sandy soil, were observed. During the 42-day experiment, 45.3%, 61.4% and 72.5% of the initial dose of CP, FT, and PT, respectively, was removed in sandy soil whereas the degradation of CP, FT, and PT in the same period, in sandy loam and silty soils reached 61.4%, 79.7% and 64.2%, and 68.9%, 81.0% and 63.6%, respectively. S. marcescens introduced into sterile soils showed a higher degradation potential (5-13%) for OPPs removal than those observed in non-sterile soil with naturally occurring attenuation. Inoculation of non-sterile soils with S. marcescens enhanced the disappearance rates of all insecticides, and DT50 for CP, FT, and PT was reduced by 20.7, 11.3 and 13.0 days, and 11.9, 7.0 and 8.1 days, and 9.7, 14.5 and 12.6 days in sandy, sandy loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. This ability of S. marcescens makes it a suitable strain for bioremediation of soils contaminated with OPPs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Lysophosphatidylcholine hydrolases of human erythrocytes, lymphocytes, and brain: Sensitive targets of conserved specificity for organophosphorus delayed neurotoxicants

    International Nuclear Information System (INIS)

    Vose, Sarah C.; Holland, Nina T.; Eskenazi, Brenda; Casida, John E.

    2007-01-01

    Brain neuropathy target esterase (NTE), associated with organophosphorus (OP)-induced delayed neuropathy, has the same OP inhibitor sensitivity and specificity profiles assayed in the classical way (paraoxon-resistant, mipafox-sensitive hydrolysis of phenyl valerate) or with lysophosphatidylcholine (LysoPC) as the substrate. Extending our earlier observation with mice, we now examine human erythrocyte, lymphocyte, and brain LysoPC hydrolases as possible sensitive targets for OP delayed neurotoxicants and insecticides. Inhibitor profiling of human erythrocytes and lymphocytes gave the surprising result of essentially the same pattern as with brain. Human erythrocyte LysoPC hydrolases are highly sensitive to OP delayed neurotoxicants, with in vitro IC 50 values of 0.13-85 nM for longer alkyl analogs, and poorly sensitive to the current OP insecticides. In agricultural workers, erythrocyte LysoPC hydrolyzing activities are similar for newborn children and their mothers and do not vary with paraoxonase status but have high intersample variation that limits their use as a biomarker. Mouse erythrocyte LysoPC hydrolase activity is also of low sensitivity in vitro and in vivo to the OP insecticides whereas the delayed neurotoxicant ethyl n-octylphosphonyl fluoride inhibits activity in vivo at 1-3 mg/kg. Overall, inhibition of blood LysoPC hydrolases is as good as inhibition of brain NTE as a predictor of OP inducers of delayed neuropathy. NTE and lysophospholipases (LysoPLAs) both hydrolyze LysoPC, yet they are in distinct enzyme families with no sequence homology and very different catalytic sites. The relative contributions of NTE and LysoPLAs to LysoPC hydrolysis and clearance from erythrocytes, lymphocytes, and brain remain to be defined

  15. Integrated Lateral Flow Test Strip with Electrochemical Sensor for Quantification of Phosphorylated Cholinesterase: Biomarker of Exposure to Organophosphorus Agents

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dan; Wang, Jun; Wang, Limin; Lu, Donglai; Lin, Yuehe

    2012-02-08

    An integrated lateral flow test strip with electrochemical sensor (LFTSES) device with rapid, selective and sensitive response for quantification of exposure to organophosphorus (OP) pesticides and nerve agents has been developed. The principle of this approach is based on parallel measurements of post-exposure and baseline acetylcholinesterase (AChE) enzyme activity, where reactivation of the phosphorylated AChE is exploited to enable measurement of total amount of AChE (including inhibited and active) which is used as a baseline for calculation of AChE inhibition. Quantitative measurement of phosphorylated adduct (OP-AChE) was realized by subtracting the active AChE from the total amount of AChE. The proposed LFTSES device integrates immunochromatographic test strip technology with electrochemical measurement using a disposable screen printed electrode which is located under the test zone. It shows linear response between AChE enzyme activity and enzyme concentration from 0.05 to 10 nM, with detection limit of 0.02 nM. Based on this reactivation approach, the LFTSES device has been successfully applied for in vitro red blood cells inhibition studies using chlorpyrifos oxon as a model OP agent. This approach not only eliminates the difficulty in screening of low-dose OP exposure because of individual variation of normal AChE values, but also avoids the problem in overlapping substrate specificity with cholinesterases and avoids potential interference from other electroactive species in biological samples. It is baseline free and thus provides a rapid, sensitive, selective and inexpensive tool for in-field and point-of-care assessment of exposures to OP pesticides and nerve agents.

  16. An Age-Dependent Physiologically-Based Pharmacokinetic/Pharmacodynamic Model for the Organophosphorus Insecticide Chlorpyrifos in the Preweanling Rat

    Energy Technology Data Exchange (ETDEWEB)

    Timchalk, Chuck; Kousba, Ahmed A.; Poet, Torka S.

    2007-08-01

    Juvenile rats are more susceptible than adults to the acute toxicity of organophosphorus insecticides like chlorpyrifos (CPF). Age- and dose-dependent differences in metabolism may be responsible. Of importance is CYP450 activation and detoxification of CPF to chlorpyrifos-oxon (CPF-oxon) and trichloropyridinol (TCP), as well as B-esterase (cholinesterase; ChE) and A-esterase (PON-1) detoxification of CPF-oxon to TCP. In the current study, a modified physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model incorporating age-dependent changes in CYP450, PON-1, and tissue ChE levels for rats was developed. In this model, age was used as a dependent function to estimate body weight which was then used to allometrically scale both metabolism and tissue ChE levels. Model simulations suggest that preweanling rats are particularly sensitive to CPF toxicity, with levels of CPF-oxon in blood and brain disproportionately increasing, relative to the response in adult rats. This age-dependent non-linear increase in CPF-oxon concentration may potentially result from the depletion of non-target B-esterases, and a lower PON-1 metabolic capacity in younger animals. These results indicate that the PBPK/PD model behaves consistently with the general understanding of CPF toxicity, pharmacokinetics and tissue ChE inhibition in neonatal and adult rats. Hence, this model represents an important starting point for developing a computational model to assess the neurotoxic potential of environmentally relevant organophosphate exposures in infants and children.

  17. Plug-In Electric Vehicle Handbook for Workplace Charging Hosts

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    Plug-in electric vehicles (PEVs) have immense potential for increasing the country's energy, economic, and environmental security, and they will play a key role in the future of U.S. transportation. By providing PEV charging at the workplace, employers are perfectly positioned to contribute to and benefit from the electrification of transportation. This handbook answers basic questions about PEVs and charging equipment, helps employers assess whether to offer workplace charging for employees, and outlines important steps for implementation.

  18. Utilities Power Change: Engaging Commercial Customers in Workplace Charging

    Energy Technology Data Exchange (ETDEWEB)

    Lommele, Stephen; Dafoe, Wendy

    2016-06-01

    As stewards of an electric grid that is available almost anywhere people park, utilities that support workplace charging are uniquely positioned to help their commercial customers be a part of the rapidly expanding network of charging infrastructure. Utilities understand the distinctive challenges of their customers, have access to technical information about electrical infrastructure, and have deep experience modeling and managing demand for electricity. This case study highlights the experiences of two utilities with workplace charging programs.

  19. Electrostatic plasma lens for focusing negatively charged particle beams.

    Science.gov (United States)

    Goncharov, A A; Dobrovolskiy, A M; Dunets, S M; Litovko, I V; Gushenets, V I; Oks, E M

    2012-02-01

    We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

  20. Transformational leadership training programme for charge nurses.

    Science.gov (United States)

    Duygulu, Sergul; Kublay, Gulumser

    2011-03-01

    This paper is a report of an evaluation of the effects of a transformational leadership training programme on Unit Charge Nurses' leadership practices. Current healthcare regulations in the European Union and accreditation efforts of hospitals for their services mandate transformation in healthcare services in Turkey. Therefore, the transformational leadership role of nurse managers is vital in determining and achieving long-term goals in this process. The sample consisted of 30 Unit Charge Nurses with a baccalaureate degree and 151 observers at two university hospitals in Turkey. Data were collected using the Leadership Practices Inventory-Self and Observer (applied four times during a 14-month study process from December 2005 to January 2007). The transformational leadership training programme had theoretical (14 hours) and individual study (14 hours) in five sections. Means, standard deviations and percentages, repeated measure tests and two-way factor analysis were used for analysis. According the Leadership Practices Inventory-Self and Observer ratings, leadership practices increased statistically significantly with the implementation of the programme. There were no significant differences between groups in age, length of time in current job and current position. The Unit Charge Nurses Leadership Practices Inventory self-ratings were significantly higher than those of the observers. There is a need to develop similar programmes to improve the leadership skills of Unit Charge Nurses, and to make it mandatory for nurses assigned to positions of Unit Charge Nurse to attend this kind of leadership programme. © 2010 Blackwell Publishing Ltd.

  1. Martian Atmospheric Pressure Static Charge Elimination Tool

    Science.gov (United States)

    Johansen, Michael R.

    2014-01-01

    A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

  2. Ejecta from single-charge cratering explosions

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, R H

    1970-05-15

    The objective was to obtain experimental data tracing the location of ejecta to its origin within the crater region. The experiment included ten high-explosive spherical charges weighing from 8 to 1000 pounds and detonated in a playa dry lake soil on the Tonopah Test Range. Each event included from 24 to 40 locations of distinctly different tracer material embedded in a plane in the expected crater region. Tracers consisted of glass, ceramic and bugle beads, chopped metal, and plastic wire. Results of this experiment yielded data on tracer dispersion as a function of charge weight, charge burial depth and tracer emplacement position. Tracer pattern parameters such as center-of-tracer mass, range to center-of-tracer mass, and angle to center-of-tracer mass were determined. There is a clear tendency for range (to center-of-tracer mass) and the size of the dispersion pattern to decrease as tracer emplacement depth increases. Increasing tracer emplacement depth and range tends to decrease the area over which tracers are dispersed on the ground surface. Tracers at the same scaled position relative to the charge were deposited closer to the crater (on a scaled basis) as charge weight was increased. (author)

  3. Quick charge battery

    Energy Technology Data Exchange (ETDEWEB)

    Parise, R.J.

    1998-07-01

    Electric and hybrid electric vehicles (EVs and HEVs) will become a significant reality in the near future of the automotive industry. Both types of vehicles will need a means to store energy on board. For the present, the method of choice would be lead-acid batteries, with the HEV having auxiliary power supplied by a small internal combustion engine. One of the main drawbacks to lead-acid batteries is internal heat generation as a natural consequence of the charging process as well as resistance losses. This limits the re-charging rate to the battery pack for an EV which has a range of about 80 miles. A quick turnaround on recharge is needed but not yet possible. One of the limiting factors is the heat buildup. For the HEV the auxiliary power unit provides a continuous charge to the battery pack. Therefore heat generation in the lead-acid battery is a constant problem that must be addressed. Presented here is a battery that is capable of quick charging, the Quick Charge Battery with Thermal Management. This is an electrochemical battery, typically a lead-acid battery, without the inherent thermal management problems that have been present in the past. The battery can be used in an all-electric vehicle, a hybrid-electric vehicle or an internal combustion engine vehicle, as well as in other applications that utilize secondary batteries. This is not restricted to only lead-acid batteries. The concept and technology are flexible enough to use in any secondary battery application where thermal management of the battery must be addressed, especially during charging. Any battery with temperature constraints can benefit from this advancement in the state of the art of battery manufacturing. This can also include nickel-cadmium, metal-air, nickel hydroxide, zinc-chloride or any other type of battery whose performance is affected by the temperature control of the interior as well as the exterior of the battery.

  4. Charge transfer in astrophysical nebulae

    International Nuclear Information System (INIS)

    Shields, G.A.

    1990-01-01

    Charge transfer has become a standard ingredient in models of ionized nebulae, supernovae remnants and active galactic nuclei. Charge transfer rate coefficients and the physics of ionized nebulae are considered. Charge transfer is applied to the ionization structure and line emission of ionized nebulae. Photoionized nebulae observations are used to test theoretical predictions of charge transfer rates. (author)

  5. Electric and hybrid vehicles charge efficiency tests of ESB EV-106 lead acid batteries

    Science.gov (United States)

    Rowlette, J. J.

    1981-01-01

    Charge efficiencies were determined by measurements made under widely differing conditions of temperature, charge procedure, and battery age. The measurements were used to optimize charge procedures and to evaluate the concept of a modified, coulometric state of charge indicator. Charge efficiency determinations were made by measuring gassing rates and oxygen fractions. A novel, positive displacement gas flow meter which proved to be both simple and highly accurate is described and illustrated.

  6. Consumption of fruits and vegetables and probabilistic assessment of the cumulative acute exposure to organophosphorus and carbamate pesticides of schoolchildren in Slovenia.

    Science.gov (United States)

    Blaznik, Urška; Yngve, Agneta; Eržen, Ivan; Hlastan Ribič, Cirila

    2016-02-01

    Adequate consumption of fruits and vegetables is a part of recommendations for a healthy diet. The aim of the present study was to assess acute cumulative dietary exposure to organophosphorus and carbamate pesticides via fruit and vegetable consumption by the population of schoolchildren aged 11-12 years and the level of risk for their health. Cumulative probabilistic risk assessment methodology with the index compound approach was applied. Slovenia, primary schools. Schoolchildren (n 1145) from thirty-one primary schools in Slovenia. Children were part of the PRO GREENS study 2009/10 which assessed 11-year-olds' consumption of fruit and vegetables in ten European countries. The cumulative acute exposure amounted to 8.3 (95% CI 7.7, 10.6) % of the acute reference dose (ARfD) for acephate as index compound (100 µg/kg body weight per d) at the 99.9th percentile for daily intake and to 4.5 (95% CI 3.5, 4.7) % of the ARfD at the 99.9th percentile for intakes during school time and at lunch. Apples, bananas, oranges and lettuce contributed most to the total acute pesticides intake. The estimations showed that acute dietary exposure to organophosphorus and carbamate pesticides is not a health concern for schoolchildren with the assessed dietary patterns of fruit and vegetable consumption.

  7. Isolation of the opdE gene that encodes for a new hydrolase of Enterobacter sp. capable of degrading organophosphorus pesticides.

    Science.gov (United States)

    Chino-Flores, Concepción; Dantán-González, Edgar; Vázquez-Ramos, Alejandra; Tinoco-Valencia, Raunel; Díaz-Méndez, Rafael; Sánchez-Salinas, Enrique; Castrejón-Godínez, Maria Luisa; Ramos-Quintana, Fernando; Ortiz-Hernández, Maria Laura

    2012-06-01

    Microbial enzymes that can hydrolyze organophosphorus compounds have been isolated, identified and characterized from different microbial species in order to use them in biodegradation of organophosphorus compounds. We isolated a bacterial strain Cons002 from an agricultural soil bacterial consortium, which can hydrolyze methyl-parathion (MP) and other organophosphate pesticides. HPLC analysis showed that strain Cons002 is capable of degrading pesticides MP, parathion and phorate. Pulsed-field gel electrophoresis and 16S rRNA amplification were performed for strain characterization and identification, respectively, showing that the strain Cons002 is related to the genus Enterobacter sp. which has a single chromosome of 4.6 Mb and has no plasmids. Genomic library was constructed from DNA of Enterobacter sp. Cons002. A gene called opdE (Organophosphate Degradation from Enterobacter) consists of 753 bp and encodes a protein of 25 kDa, which was isolated using activity methods. This gene opdE had no similarity to any genes reported to degrade organophosphates. When kanamycin-resistance cassette was placed in the gene opdE, hydrolase activity was suppressed and Enterobacter sp. Cons002 had no growth with MP as a nutrients source.

  8. [High throuput analysis of organophosphorus pesticide residues and their metabolites in animal original foods by dual gas chromatography-dual pulse flame photometric detection].

    Science.gov (United States)

    Yang, Lixin; Li, Heli; Miao, Hong; Zeng, Fangang; Li, Ruifeng; Chen, Huijing; Zhao, Yunfeng; Wu, Yongning

    2011-10-01

    A method was established for the quantitative determination of 54 organophosphorus pesticide residues and their metabolites in foods of animal origin by dual gas chromatography-dual pulse flame photometric detection. Homogenized samples were extracted with acetone and methylene chloride, and cleaned-up by gel permeation chromatography (GPC). The response of each analyte showed a good linearity with a correlation coefficient not less than 0. 99. The recovery experiments were performed by a blank sample spiked at low, medium and high fortification levels. The recoveries for beef, mutton, pork, chicken were in the range of 50. 5% -128. 1% with the relative standard deviations (n = 6) of 1. 1% -25. 5%, which demonstrated the good precision and accuracy of the present method. The limits of detection for the analytes were in the range of 0. 001 -0. 170 mg/kg, and the limits of quantification were in the range of 0. 002 -0. 455 mg/kg. Animal food samples collected from markets such as meat, liver and kidney were analyzed, and the residues of dichlorovos and disulfoton-sulfoxide were found in the some samples. The established method is sensitive and selective enough to detect organophosphorus pesticide residues in animal foods.

  9. Developmental exposure to terbutaline alters cell signaling in mature rat brain regions and augments the effects of subsequent neonatal exposure to the organophosphorus insecticide chlorpyrifos

    International Nuclear Information System (INIS)

    Meyer, Armando; Seidler, Frederic J.; Aldridge, Justin E.; Slotkin, Theodore A.

    2005-01-01

    Exposure to apparently unrelated neurotoxicants can nevertheless converge on common neurodevelopmental events. We examined the long-term effects of developmental exposure of rats to terbutaline, a β-adrenoceptor agonist used to arrest preterm labor, and the organophosphorus insecticide chlorpyrifos (CPF) separately and together. Treatments mimicked the appropriate neurodevelopmental stages for human exposures: terbutaline on postnatal days (PN) 2-5 and CPF on PN11-14, with assessments conducted on PN45. Although neither treatment affected growth or viability, each elicited alterations in CNS cell signaling mediated by adenylyl cyclase (AC), a transduction pathway shared by numerous neuronal and hormonal signals. Terbutaline altered signaling in the brainstem and cerebellum, with gender differences particularly notable in the cerebellum (enhanced AC in males, suppressed in females). By itself, CPF exposure elicited deficits in AC signaling in the midbrain, brainstem, and striatum. However, sequential exposure to terbutaline followed by CPF produced larger alterations and involved a wider spectrum of brain regions than were obtained with either agent alone. In the cerebral cortex, adverse effects of the combined treatment intensified between PN45 and PN60, suggesting that exposures alter the long-term program for development of synaptic communication, leading to alterations in AC signaling that emerge even after adolescence. These findings indicate that terbutaline, like CPF, is a developmental neurotoxicant, and reinforce the idea that its use in preterm labor may create a subpopulation that is sensitized to long-term CNS effects of organophosphorus insecticides

  10. Charge pulse preamplifier

    International Nuclear Information System (INIS)

    Libs, Gerard.

    1973-01-01

    A charge pulse preamplifier with very low background noise is described. The inlet stage of that preamplifier comprises a cooled field-effect transistor receiving the signal to be amplified at its gate input. Preferably, the charge resistor of said transistor is a field effect transistor, the source inlet of which is connected to the drain inlet of the former transistor through a self-induction coil and a resistor mounted in series. This can be applied to the treatment of the signals delivered by a particle detector in the form of a semi-conductor [fr

  11. Researcher positioning

    DEFF Research Database (Denmark)

    Mørck, Line Lerche; Khawaja, Iram

    2009-01-01

    abstract  This article focuses on the complex and multi-layered process of researcher positioning, specifically in relation to the politically sensitive study of marginalised and ‘othered' groups such as Muslims living in Denmark. We discuss the impact of different ethnic, religious and racial...... political and personal involvement by the researcher, which challenges traditional perspectives on research and researcher positioning. A key point in this regard is the importance of constant awareness of and reflection on the multiple ways in which one's positioning as a researcher influences the research...

  12. Charge-transfer spectra of tetravalent lanthanide ions in oxides

    NARCIS (Netherlands)

    Hoefdraad, H.E.

    The charge-transfer spectra of Ce4+, Pr4+ and Tb4+ in a number of oxides are reported. It is noted that the position of the first charge-transfer band is fixed for the metal ion in an oxygen coordination of VI, but varies in VIII coordination as a function of the host lattice. It is argued that this

  13. Percolative transport in the vicinity of charge-order ferromagnetic ...

    Indian Academy of Sciences (India)

    field driven charge transport in the system is modelled on the basis of an inhomogeneous medium consisting of ... The charge-ordered phase for incommensurate distribution of man- ganese ions (i.e. ... position x = 0.35 measured in a constant voltage mode. The electric ... a drop in resistance on decreasing the temperature.

  14. Radiographic positioning

    International Nuclear Information System (INIS)

    Eisenberg, R.L.; Dennis, C.A.; May, C.

    1989-01-01

    This book concentrates on the routine radiographic examinations commonly performed. It details the wide variety of examinations possible and their place in initial learning and in the radiology department as references for those occasions when an unusual examination is requested. This book provides information ranging from basic terminology to skeletal positioning to special procedures. Positions are discussed and supplemented with a picture of a patient, the resulting radiograph, and a labeled diagram. Immobilization and proper shielding of the patient are also shown

  15. Position encoder

    International Nuclear Information System (INIS)

    Goursky, Vsevolod

    1975-01-01

    A circuitry for deriving the quotient of signal delivered by position-sensitive detectors is described. Digital output is obtained in the form of 10- to 12-bit words. Impact position may be determined with 0.25% accuracy when the dynamic range of the energy signal is less 1:10, and 0.5% accuracy when the dynamic range is 1:20. The division requires an average time of 5μs for 10-bit words

  16. Position encoder

    International Nuclear Information System (INIS)

    Goursky, V.

    1975-05-01

    This paper describes circuitry for deriving the quotient of signals delivered by position-sensitive detectors. Digital output is obtained in the form of 10 to 12 bit words. Impact position may be determined with 0.25% accuracy when the dynamic range of the energy signal is less than 1:10, and 0.5% accuracy when the dynamic range is 1:20. The division requires an average time of 5μs for 10-bit words [fr

  17. Designing your boron-charging system

    International Nuclear Information System (INIS)

    Miller, J.

    1979-01-01

    High-pressure positive-displacement pumps used in the boron-charging setups of pressurized-water (PWR) nuclear plants because of their inherently high efficiencies over a wide range of pressures and speeds are described. Hydrogen-saturated water containing 4-12% boric acid is fed to the pump from a volume-control tank under a gas blanket. Complicated piping and the pulsation difficulties associated with reciprocating pumps make hydrogen-saturated boron-charging systems a challenge to the designer. The article describes the unusual hydraulics of the systems to help assure a trouble-free design

  18. Charged particle beams

    CERN Document Server

    Humphries, Stanley

    2013-01-01

    Detailed enough for a text and sufficiently comprehensive for a reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams. Subjects include stochastic cooling, high-brightness injectors, and the free electron laser. Humphries provides students with the critical skills necessary for the problem-solving insights unique to collective physics problems. 1990 edition.

  19. Charged fluids with symmetries

    Indian Academy of Sciences (India)

    It is possible to introduce many types of symmetries on the manifold which restrict the ... metric tensor field and generate constants of the motion along null geodesics .... In this analysis we have studied the role of symmetries for charged perfect ...

  20. Charged singularities: repulsive effects

    Energy Technology Data Exchange (ETDEWEB)

    De Felice, F; Nobili, L [Padua Univ. (Italy). Ist. di Fisica; Calvani, M [Padua Univ. (Italy). Ist. di Astronomia

    1980-07-01

    The repulsive phenomena which a particle experiences in the vicinity of a naked singularity are investigated in the Kerr-Newman space-time. The aim is to extend the knowledge of this fact to charged solutions and to have a direct indication of how, in these situations, the gravitational and electrostatic interactions are competing.