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1.
J Environ Manage ; 329: 116983, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36565500

RESUMO

Radioactive cesium-rich microparticles (CsMPs) derived from the Fukushima Daiichi Nnuclear Power Plant accident were detected from soils and river water around Fukushima Prefecture, Japan. Because CsMPs are insoluble and rich in radioactive cesium (RCs), they may cause the overestimation of solid-water distribution coefficient (Kd) for RCs in the water. Previous studies showed the proportion of RCs derived from CsMPs on RCs concentration in soils collected from areas with different contaminated levels. Because the proportion of RCs concentration derived CsMPs to the RCs concentration of soils in the less contaminated areas is higher than that in the highly contaminated areas, the effect of CsMPs on particulate RCs concentration in river water may be larger in the less contaminated areas. However, the difference in the effects of CsMPs on the particulate RCs concentration and Kd in river water flowing through watersheds with different contaminated levels has not been clarified. In this study, we investigated the effect of CsMPs on the particulate RCs concentration and Kd in two rivers, Takase River and Kami-Oguni River, flowing through the watersheds with different RCs contaminated levels in Fukushima Prefecture. CsMPs might enter rivers due to soil erosion because they were detected only in some samples collected from both rivers during flood events. CsMPs accounted for more than half of particulate RCs concentration in some water samples collected in the flood condition. In particular, the proportion of CsMPs in particulate RCs for the Kami-Oguni River was greater than that for the Takase River. However, when evaluating for the entire water sampling in the flood condition, a proportion of RCs concentration derived from CsMPs in the average RCs concentrations per unit mass of SS in both river waters collected in the flood condition was not large. CsMPs might temporarily increase the particulate RCs concentration and Kd in the flood event, but CsMPs did not significantly affect them when evaluated throughout the event.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos da Água , Radioisótopos de Césio/análise , Rios , Poluentes Radioativos da Água/análise , Césio , Água , Poeira , Japão , Centrais Nucleares , Solo
2.
Langmuir ; 38(44): 13577-13583, 2022 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-36279511

RESUMO

Despite the popular use of citrate for the reduction of silver ions, this process suffers from slow crystal growth and broad size distribution. The rapid and effective synthesis of highly concentrated and stable spherical silver nanoparticles (AgNPs) confined in the surfactant-rich phase of thermoresponsive 3-(alkyldimethylammonio)-propyl sulfate surfactants obtained after reaction with citrate ions at high temperature is described. The present approach using the zwitterionic surfactant offers an alternative rapid approach for production of AgNPs and an in situ phase separation step that serves to "extract" and concentrate the AgNPs in the surfactant-rich phase. Almost all (synthetic yield 99.9%, extraction efficiency 98.6%) of the synthesized AgNPs with a diameter of 21.0 ± 2.5 nm were incorporated into the phase-separated surfactant-rich phase at pH 11, and the capacity (maximum concentration) was 3.4 × 1013 particles/mL. The AgNPs were stable upon long-term storage (at least 3 months).


Assuntos
Nanopartículas Metálicas , Prata , Prata/química , Nanopartículas Metálicas/química , Tensoativos , Extratos Vegetais/química , Citratos
3.
Molecules ; 25(24)2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33327547

RESUMO

Carbonyl complexes with manganese(I) as the central metal are very attractive catalysts. The introduction of redox-active ligands, such as quinones and methyl viologen analogs into these catalysts, would be expected to lead to superior catalyst performances, since they can function as excellent electron carriers. In this study, we synthesized four tricarbonylmanganese(I) complexes containing typical bidentate polypyridyl ligands, including 1,10-phenanthroline (phen) and 2,2'-bipyridine (bpy) frameworks bound to redox-active ortho-quinone/catechol or methyl viologen-like units. The molecular structures of the resulting complexes were determined by X-ray crystallography to clarify their steric features. As expected from the infrared (IR) data, three CO ligands for each complex were coordinated in the facial configuration around the central manganese(I) atom. Additionally, the structural parameters were found to differ significantly between the quinone/catechol units. Electrochemical analysis revealed some differences between them and their reference complexes, namely [MnBr(CO)3(phen)] and [MnBr(CO)3(bpy)]. Notably, interconversions induced by two-electron/two-proton transfers between the quinone and catechol units were observed in the phenanthroline-based complexes. This work indicated that the structural and redox properties in tricarbonylmanganese(I) complexes were significantly affected by chemically modified polypyridyl ligands. A better understanding of structures and redox behaviors of the present compounds would facilitate the design of new manganese complexes with enhanced properties.


Assuntos
Elétrons , Manganês/química , Compostos Organometálicos/química , Fenantrolinas/química , Piridinas/química , Quinonas/química , Catálise , Catecóis/química , Eletroquímica , Humanos , Oxirredução , Paraquat/química , Polimerização , Prótons
4.
Molecules ; 25(1)2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31861731

RESUMO

The reactivities of transition metal coordination compounds are often controlled by the environment around the coordination sphere. For ruthenium(II) complexes, differences in polypyridyl supporting ligands affect some types of reactivity despite identical coordination geometries. To evaluate the synergistic effects of (i) the supporting ligands, and (ii) the coordination geometry, a series of dicarbonyl-ruthenium(II) complexes that contain both asymmetric and symmetric bidentate polypyridyl ligands were synthesized. Molecular structures of the complexes were determined by X-ray crystallography to distinguish their steric configuration. Structural, computational, and electrochemical analysis revealed some differences between the isomers. Photo- and thermal reactions indicated that the reactivities of the complexes were significantly affected by both their structures and the ligands involved.


Assuntos
Complexos de Coordenação/química , Piridinas/química , Rutênio/química , Cristalografia por Raios X , Isomerismo , Ligantes , Modelos Moleculares , Estrutura Molecular
5.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 1): m1-2, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23476313

RESUMO

In the title compound, [RuCl(C10H8N2)2(CO)]PF6, the Ru(II) atom is coordinated in a distorted octa-hedral geometry by four N atoms of the bipyridine ligands, a carbonyl C atom and a chloride ion. The carbonyl and chloride ligands in the cation adopt a mutually cis arrangement and these are disordered over two sets of sites with site occupancies of 0.721 (6) and 0.279 (6). The Ru-N bond length [2.117 (2) Å] trans to the carbonyl ligand is slightly longer than the average of the other Ru-N bond lengths (2.08 Å), which can be explained by the expected trans influence of the carbonyl group. In the crystal, weak C-H⋯F inter-actions are observed between the complex cation and the PF6(-) anion, leading to the formation of a three-dimensional supramolecular structure. The crystal studied was an inversion twin with twin fractions of 0.78 (4) and 0.22 (4).

6.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 4): m227-8, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23634019

RESUMO

The asymmetric unit of the title compound, [Fe4(C6H6O4S2)2(C10H15)2S4]PF6, contains two different complex cations and two PF6 (-) anions. The two complex cations have similar conformations with the butterfly-like Fe4S4 core surrounded by two penta-methyl-cyclo-penta-dienyl ligands and the S atoms of two dithiol-ate ligands. In each Fe4S4 core, there are four short Fe-Fe and two long Fe⋯Fe contacts, suggesting bonding and non-bonding inter-actions, respectively. The Fe-S distances range from 2.1287 (13) to 2.2706 (16) Šfor one and from 2.1233 (13) to 2.2650 (16) Šfor the other Fe4S4 core. The Fe-S distances involving the dithiol-ate ligands are in a more narrow range [2.1764 (16)-2.1874 (13) Šfor one and 2.1743 (14)-2.1779 (16) Šfor the other cation]. There are no significant inter-actions between cations and anions.

7.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 4): m181, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23633986

RESUMO

The title compound, [Fe4(C10H15)2(C8H10O4S2)2S4], contains a twisted Fe4S4 cubane-like core. A twofold rotation axis passes through the Fe4S4 core, completing the coordination of the four Fe atoms with two penta-methyl-cyclo-penta-dienyl ligands and two chelating dithiol-ate ligands. There are three short Fe-Fe and three long Fe⋯Fe contacts in the Fe4S4 core, suggesting bonding and non-bonding inter-actions, respectively. The Fe-S bonds in the Fe4S4 core range from 2.1523 (5) to 2.2667 (6) Šand are somewhat longer than the Fe-S bonds involving the dithiol-ate ligand.

8.
IUCrdata ; 8(Pt 8): x230657, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37693785

RESUMO

The title cluster compound, [Mo4(η5-C5H4Me)4(µ3-Se)4], was synthesized from the reaction of [Mo(η5-C5H4Me)(CO)3]2 with grey selenium in refluxing xylene solution under a nitro-gen atmosphere. The complete cluster is generated by a crystallographic twofold axis and contains an Mo4Se4 cubane-like core surrounded by four η5-methylcyclo-pentadienyl ligands. In the core, the four molybdenum atoms are connected to each other to form a tetra-hedron, with a selenium atom capping each face. The Mo-Mo bond lengths vary from 2.9857 (5) to 3.0083 (3) Šand the Mo-Se separations range from 2.4633 (4) to 2.4693 (5) Å.

9.
Heliyon ; 9(4): e14876, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37089340

RESUMO

Mononuclear Ru complexes catalyze dioxygen formation via water splitting; therefore, a detailed investigation into their water-oxidation process is necessary. In this study, we synthesized a series of Ru(III) complexes containing a dianionic tridentate ligand with three pyridine groups (one coordinated to Ru while the other two are "free") and investigated their substitution reactions in a water/acetonitrile mixture. Among the monodentate pyridyl ligands, the one at the equatorial position was crystallographically proven to be selectively substituted. Therefore, our results experimentally demonstrate the proposed coordination geometry for an intermediate during water oxidation over Ru complexes.

10.
Acta Crystallogr E Crystallogr Commun ; 78(Pt 6): 545-549, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36072152

RESUMO

The mol-ecular and crystal structures of two ruthenium(II) complexes, viz. cis-aqua-[2,6-bis-(1,8-naphthyridin-2-yl)pyridine-κ3 N,N',N''](thio-cyanato-κN)(tri-phen-yl-phosphine-κP)ruthenium(II) hexa-fluorido-phosphate-acetone-water (1/0.5/1), [Ru(NCS)(C21H13N5)(C18H15P)(H2O)]PF6·0.5C3H6O·H2O (I) and trans-[2,6-bis-(1,8-naphthyridin-2-yl)pyridine-κ3'N,N',N'']bis-(pyridine-κN)(thiocyanato-κN)ruthenium(II) thio-cyanate, [Ru(NCS)(C21H13N5)(C5H5N)2]NCS (II), with an N-coordinating thio-cyanato group and a tridentate polypyridyl supporting ligand, are reported. The RuII atom in each of the cationic complexes adopts a distorted octa-hedral coordination sphere, defined by an N atom of the thio-cyanato ligand, three N atoms from the tridentate polypyridyl ligand, and an O and P atom in (I) or two pyridine-N atoms in (II) derived from monodentate ligands. The thio-cyanato ligand in (I) coordinates in an axial manner to the {Ru-dnp} unit [dnp = 2,6-bis-(1,8-naphthyridin-2-yl)pyridine], whereas it coordinates in an equatorial manner in (II). In the crystal structure of compound (I), intra-molecular C-H⋯O, C-H⋯N and O-H⋯N hydrogen bonds as well as π-π contacts are present, in addition to inter-molecular C-H⋯F, C-H⋯O and O-H⋯O hydrogen bonds. In the crystal structure of compound (II), intra-molecular C-H⋯N hydrogen bonds are observed along with inter-molecular C-H⋯N and C-H⋯S hydrogen bonds as well as a π-π inter-action.

11.
Environ Pollut ; 292(Pt B): 118479, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34752791

RESUMO

The 2011 Tohoku earthquake-tsunami and the subsequent nuclear accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS) led to large-scale radionuclide contamination of the marine and freshwater environment. Monitoring studies of marine food products in the Fukushima region have generally demonstrated a declining trend in radiocaesium concentrations. However, the accumulation and elimination of radiocaesium and potential biological effects remain poorly understood for freshwater biota inhabiting highly contaminated areas at Fukushima. Consequently, the present study aimed to assess radiocaesium accumulation and developmental effects on the commercially important catadromous Japanese mitten crab, Eriocheir japonica. E. japonica were collected from four sites along a gradient of radionuclide contamination 4-44 km in distance from the FDNPS in 2017. To determine potential developmental effects, fluctuating asymmetry (FA) was used as a measure of developmental stability. Combined 134Cs and 137Cs values for whole E. japonica from highly contaminated sites 4 and 16 km in distance from the FDNPS were 3040 ± 521 and 2250 ± 908 Bq kg-1 wet weight respectively, 30 and 22 times greater than the Japanese standard limit of 100 Bq kg-1. Estimated total dose rates based on radiocaesium concentrations in whole crabs and sediment ranged from 0.016 to 37.7 µGy h-1. No significant relationship between radiocaesium accumulation and FA was recorded, suggesting that chronic radiation exposure at Fukushima is not inducing developmental effects in E. japonica as measured using fluctuating asymmetry. Furthermore, estimated dose rates were below proposed regulatory limits where significant deleterious effects are expected. The present study will aid in the understanding of the long-term consequences of radiation exposure for non-human biota and the management of radioactively contaminated environments.


Assuntos
Acidente Nuclear de Fukushima , Exposição à Radiação , Monitoramento de Radiação , Poluentes Radioativos da Água , Radioisótopos de Césio/análise , Japão , Poluentes Radioativos da Água/análise
12.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 6): m737-8, 2011 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-21754631

RESUMO

The asymmetric unit of the title compound, [Ru(C(13)H(9)N(3))(C(15)H(11)N(3))(H(2)O)](PF(6))(2)·1.5C(3)H(6)O, consists of two crystallographically independent Ru(II) complexes. Each complex is approximately octa-hedral with the Ru(II) atom bound by an N,N'-coordinated 2-(2-pyrid-yl)-1,8-naphthyridine (pynp) ligand, a meridional 2,2':6',2''-terpyridine (tpy) ligand and one aqua ligand. The tpy ligand is coordinated in a planar tridentate fashion with the central N atom closest to the Ru(II) atom. The aqua ligand is trans to the pyridine N atom of pynp. The long Ru-O distances [2.150 (5) and 2.138 (5) Å] are typical for aqua ligands in polypyridyl ruthenium complexes. In the crystal, both intra-molecular O-H⋯N and inter-molecular O-H⋯O hydrogen bonds are observed.

13.
Dalton Trans ; 50(22): 7759-7767, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-33997875

RESUMO

Quinone derivatives and their metal complexes are well-known molecules that participate in electron-transfer reactions relevant to diverse fields. However, the fundamental knowledge on the unique reactivity of redox-active quinone complexes is limited by the difficulty in their isolation. Herein, the synthesis of isolable mononuclear polypyridylruthenium(ii) complexes containing both hydroquinone and quinone units is described. Three types of monodentate ligands are conveniently used to control the electronic states of the complexes. Both reduced (hydroquinone) and oxidised (quinone) forms are successfully isolated and characterised by spectroscopic and crystallographic analysis, allowing direct comparisons of their properties. The redox-rich and visible light-responsive nature of the ruthenium complexes enables to investigate the quinone/hydroquinone interconversion induced by electron transfer, photoirradiation and photoswitching based on ligand substitution reactions. These results demonstrate the occurrence of synergistic effects between metal complexes and redox-active organic compounds.

14.
Chemosphere ; 265: 129058, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33250230

RESUMO

This study analyzes the 137Cs behavior in the ponds of Okuma Town from 2015 to 2019 in the Fukushima Dai-ichi nuclear power plant (FDNPP) exclusion zone. A decline in both particulate and dissolved 137Cs activity concentrations was revealed. The decline rate constants for the particulate 137Cs activity concentration were found to be higher than for the dissolved 137Cs activity concentration. In terms of seasonality the dissolved 137Cs concentrations were higher from June to October, depending on the specific pond and year, most likely due to temperature dependence of 137Cs desorption from frayed edge sites of micaceous clay minerals. The apparent Kd(137Cs) in the studied ponds, in absolute value, appeared to be much higher than that for closed and semi-closed lakes of the Chernobyl contaminated area; however, these were comparable to the values characteristic of the rivers and reservoirs of the FDNPP contaminated area. The apparent Kd(137Cs) in the suspended sediment-water system was observed to decrease over time. It was hypothesized that this trend was associated with the decomposition of glassy hot particles. Relying on the theory of selective sorption and fixation, the exchangeable radiocesium interception potential, RIPex(K) was estimated using data on 137Cs speciation in the surface bottom-sediment layer and its distribution in the sediment-water system. For the studied ponds, RIPex(K) was on the average 2050 mEq/kg, which is within the range of values measured in laboratory studies reported in the literature.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos da Água , Radioisótopos de Césio/análise , Japão , Centrais Nucleares , Lagoas , Poluentes Radioativos da Água/análise
15.
Environ Int ; 155: 106675, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34120002

RESUMO

The health effects associated with chronic low-dose, low-dose rate (LD-LDR) exposures to environmental radiation are uncertain. All dose-effect studies conducted outside controlled laboratory conditions are challenged by inherent complexities of ecological systems and difficulties quantifying dose to free-ranging organisms in natural environments. Consequently, the effects of chronic LD-LDR radiation exposures on wildlife health remain poorly understood and much debated. Here, samples from wild boar (Sus scrofa leucomystax) and rat snakes (Elaphe spp.) were collected between 2016 and 2018 across a gradient of radiation exposures in Fukushima, Japan. In vivo biomarkers of DNA damage and stress were evaluated as a function of multiple measurements of radiation dose. Specifically, we assessed frequencies of dicentric chromosomes (Telomere-Centromere Fluorescence in situ Hybridization: TC-FISH), telomere length (Telo-FISH, qPCR), and cortisol hormone levels (Enzyme Immunoassay: EIA) in wild boar, and telomere length (qPCR) in snakes. These biological parameters were then correlated to robust calculations of radiation dose rate at the time of capture and plausible upper bound lifetime dose, both of which incorporated internal and external dose. No significant relationships were observed between dicentric chromosome frequencies or telomere length and dose rate at capture or lifetime dose (p value range: 0.20-0.97). Radiation exposure significantly associated only with cortisol, where lower concentrations were associated with higher dose rates (r2 = 0.58; p < 0.0001), a relationship that was likely due to other (unmeasured) factors. Our results suggest that wild boar and snakes chronically exposed to LD-LDR radiation sufficient to prohibit human occupancy were not experiencing significant adverse health effects as assessed by biomarkers of DNA damage and stress.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Animais , Animais Selvagens , Radioisótopos de Césio/análise , Dano ao DNA , Humanos , Hibridização in Situ Fluorescente , Japão , Centrais Nucleares
16.
Analyst ; 135(6): 1417-25, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20498886

RESUMO

Cross-linked acrylic ester microparticles (EG50OH) with absorbed fluorescent probe molecules, such as fluorescein and acridine orange were successfully fabricated and employed as "turn-on" fluorescent sensors for the detection and determination of ammonia and organic amine vapor concentrations. Using EG50OH microparticles that had fluorescein (fluorescein fluorescent microparticle, FL-FMP sensor) incorporated as the fluorescent probe molecule (with lambda(ex) = 450 nm; lambda(em) = 528 nm), the detection limit achieved for ammonia vapor was 0.73 ppm, the response being linearly dependent on concentration over the range of 1.0-250 ppm gaseous ammonia. The FL-FMP responded to organic amines with the relative signal response following the order: triethylamine > tert-butylamine > diethylamine > n-propylamine > ammonia. A limit of detection of 0.048 ppm triethylamine vapor was achieved using this FL-FMP sensor. The sensor response is based on the acid-base properties of the fluorescent probe molecules. The fluorescent probes immobilized in/on the EG50OH are in a microenvironment such that they are in their neutral or protonated states and only exhibit weak fluorescence. Upon exposure to ammonia or amine vapor, the fluorescent species are deprotonated and exhibit much greater fluorescence emission ("turned-on" due to exposure to these basic analytes). The ease of fabrication and aforementioned properties of these fluorescent microparticle sensors are such that they should be amenable for use in a variety of situations requiring the detection or monitoring of ammonia and amines in the vapor state.


Assuntos
Aminas/análise , Amônia/análise , Corantes Fluorescentes/química , Gases/química , Polímeros/química , Espectrometria de Fluorescência/métodos , Adsorção , Fatores de Tempo
17.
Acta Crystallogr E Crystallogr Commun ; 76(Pt 9): 1433-1436, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32939295

RESUMO

The crystal structures of two manganese(I) complexes with ester-substituted bi-pyridine or bi-quinoline supporting ligands are reported, namely, fac-bromido-tricarbon-yl(diethyl 2,2'-bi-pyridine-4,4'-di-carboxyl-ate-κ2 N,N')mangan-ese(I), [MnBr(C16H16N2O4)(CO)3], I, and fac-bromido-tricarbon-yl(diethyl 2,2'-bi-quinoline-4,4'-di-carboxyl-ate-κ2 N,N')manganese(I), [MnBr(C24H20N2O4)(CO)3], II. In both complexes, the manganese(I) atom adopts a distorted octa-hedral coordination sphere defined by three carbonyl C atoms, a Br- anion and two N atoms from the chelating α-di-imine ligand. Both complexes show fac configurations of the carbonyl ligands. In I, the complex mol-ecules are linked by C-H⋯Br hydrogen bonds and aromatic π-π contacts. In II, intra-molecular C-H⋯O hydrogen bonds are present as well as inter-molecular C-H⋯O and C-H⋯Br hydrogen bonds and π-π inter-actions.

18.
Acta Crystallogr E Crystallogr Commun ; 76(Pt 7): 1139-1142, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32695468

RESUMO

The crystal structures of two manganese(I) complexes with a different coordination mode of the supporting ligand are reported: fac-bromido-tricarbon-yl(4'-phenyl-2,2':6',2''-terpyridine-κ2 N,N')manganese(I), [MnBr(C21H15N3)(CO)3], I, and cis-bromido-dicarbon-yl(4'-phenyl-2,2':6',2''-terpyridine-κ3 N,N',N'')manganese(I), [MnBr(C21H15N3)(CO)2], II. In both complexes, the manganese(I) atom is coordinated by terminal carbonyl ligands, a bromide ion, and a 4'-phenyl-2,2':6',2''-terpyridine ligand within a distorted octa-hedral environment. In I, the metal ion is facially coordinated by three carbonyl ligands and the terpyridine ligand binds in a bidentate fashion. The non-coordinating nitro-gen atom in the terpyridine ligand is positioned on the side opposite to the bromido ligand. In II, the metal ion is coordinated by two carbonyl ligands in a cis configuration and the terpyridine ligand binds in a tridentate fashion; notably, one carbonyl and the trans bromido ligand are mutually disordered over two positions. In I, the complex mol-ecules are linked by C-H⋯Br hydrogen bonds. In II, aromatic π-π contacts are present, as well as pairs of C-H⋯Br and C-H⋯O hydrogen bonds.

19.
Sci Total Environ ; 734: 139389, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32464388

RESUMO

One of the largest releases of radioactive contamination in history occurred at Japan's Fukushima Daiichi Nuclear Power Plant (FDNPP). Although the accident happened in 2011, questions still persist regarding its ecological impacts. For example, relatively little is known about radiocesium accumulation in snakes, despite their high trophic status, limited home range sizes, and close association with soil where many radionuclides accumulate. This study presents one of the most comprehensive radioecological studies of snakes published to date using a combination of whole-body radiocesium analyses, GPS transmitters, and optically stimulated luminescence (OSL) dosimeters. The objectives were to: 1) quantify whole-body radiocesium activity concentrations and internal dose rates among several common species of snakes within and around the Fukushima Exclusion Zone (FEZ), 2) determine effects of species, sex, and body size on radiocesium activity concentrations, 3) measure external dose rates using GPS-coupled dosimeters deployed on free-ranging snakes, 4) compare field-derived empirical dose rates to those generated by computer simulation software (i.e., the ERICA tool), and 5) determine if incorporating snake behavior into computer models improve simulated estimates of external dose. Whole-body radiocesium levels for snakes were highly variable among individuals (16 to 25,000 Bq/kg, FW), but were influenced more by levels of local contamination than species, sex, or size. Doses recorded by OSL dosimeters on snakes, as well as modeling in ERICA, suggest that individual movements and behavior have a substantial influence on dose rates to snakes. However, dose estimates produced with ERICA were comparable to dose received by tracked snakes. The average external plus internal dose rate for snakes captured in the FEZ was 3.6-3.9 µGy/h, with external dose contributing 80% to the total. Further research regarding reptile-specific benchmark dose rates would improve risk assessment for reptiles in radiologically contaminated areas.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Animais , Radioisótopos de Césio , Simulação por Computador , Japão , Serpentes , Poluentes Radioativos do Solo , Poluentes Radioativos da Água
20.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 9): m1117-8, 2009 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-21577461

RESUMO

In the title compound, [RuCl(C(10)H(8)N(2))(C(23)H(19)N(3)O(2))]PF(6)·CH(3)CN, the ligand environment about the Ru(II) atom is distorted octa-hedral, with the substituted terpyridyl ligand coordinated in a meridional fashion, the bipyridyl ligand coordinated in a cis fashion and the Cl atom trans to one of the bipyridyl N atoms. The Ru-N distances are in the range 2.036 (2)-2.084 (2) Šwith the exception of the central Ru-N bond from the terpyridyl ligand, which is shorter [1.9503 (19) Å], as expected. The pendant dimethoxy-phenyl substituent is not coplanar with the terpyridyl unit; the dihedral angle between the central pyridyl ring and the benzene ring is 46.72 (11)°. The anion is disordered equally over two positions around an F-P-F bond axis.

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