Tetra-μ3-selen-ido-1:2:3κ3Se;1:2:4κ3Se;1:3:4κ3Se;2:3:4κ3Se-tetrakis-[(η5-methyl-cyclo-penta-dien-yl)molybdenum(III)](6 Mo-Mo)

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) Å and the Mo-Se separations range from 2.4633 (4) to 2.4693 (5) Å.

Crystallographic evidence for the stereoselective substitution of equatorial pyridyl ligands in ruthenium(III) complexes

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.

Effect of radioactive cesium-rich microparticles on radioactive cesium concentration and distribution coefficient in rivers flowing through the watersheds with different contaminated condition in Fukushima

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 (K_d) 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 K_d 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 K_d 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 K_d in the flood event, but CsMPs did not significantly affect them when evaluated throughout the event.

Preparation of Highly Concentrated Uniform-Sized Silver Nanoparticles via Use of Thermoresponsive Zwitterionic Surfactants

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).

Isolation and structural comparison of RuII-dnp complexes [dnp = 2,6-bis(1,8-naphthyridin-2-yl)pyridine] with axially or equatorially coordinating NCS ligands

The crystal structures of two Ru^II complexes bearing a tridentate polypyridine ligand and N-coordinating thio­cyanato ligands at the axial or equatorial position are compared.

The mol­ecular and crystal structures of two ruthenium(II) complexes, viz. cis-aqua­[2,6-bis­(1,8-naphthyridin-2-yl)pyridine-κ³N,N′,N′′](thio­cyanato-κN)(tri­phen­yl­phosphine-κP)ruthenium(II) hexa­fluorido­phosphate–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) thio­cyanate, [Ru(NCS)(C₂₁H₁₃N₅)(C₅H₅N)₂]NCS (II), with an N-coordinating thio­cyanato group and a tridentate polypyridyl supporting ligand, are reported. The Ru^II atom in each of the cationic complexes adopts a distorted octa­hedral coordination sphere, defined by an N atom of the thio­cyanato 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 thio­cyanato 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), intra­molecular C—H⋯O, C—H⋯N and O—H⋯N hydrogen bonds as well as π–π contacts are present, in addition to inter­molecular C—H⋯F, C—H⋯O and O—H⋯O hydrogen bonds. In the crystal structure of compound (II), intra­molecular C—H⋯N hydrogen bonds are observed along with inter­molecular C—H⋯N and C—H⋯S hydrogen bonds as well as a π–π inter­action.

Radiocaesium accumulation and fluctuating asymmetry in the Japanese mitten crab, Eriocheir japonica, along a gradient of radionuclide contamination at Fukushima

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.

Redetermination of the crystal structure of bis[N,N′-ethylenebis(acetylacetoniminato)nickel(II)] sodium perchlorate, C24H36ClN4NaNi2O8

C24H36ClN4NaNi2O8, monoclinic, C2/c (no. 15), a = 19.5909(11) Å, b = 10.8023(6) Å, c = 14.5722(8) Å, β = 112.032(1)°, V = 2858.7(3) Å3, Z = 4, R gt (F) = 0.0260, wR ref (F 2) = 0.0701, T = 93(2) K.

Evaluation of DNA damage and stress in wildlife chronically exposed to low-dose, low-dose rate radiation from the Fukushima Dai-ichi Nuclear Power Plant accident

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.

Redetermination of the crystal structure of (2E,4Z,13E,15Z)-3,5,14,16-tetramethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosa-1(22),2,4,7,9,11,13,15,18,20-decaene, C22H24N4

C22H24N4, triclinic, P 1 ‾ $P&#x203e;{1}$ (no. 2), a = 9.217(4) Å, b = 9.774(4) Å, c = 10.843(4) Å, α = 96.770(2)°, β = 101.791(5)°, γ = 105.873(3)°, V = 903.9(6) Å3, Z = 2, R gt (F) = 0.0391, wR ref (F 2) = 0.1069, T = 93(2) K.

Hydroquinone/quinone electro- and photochemical interconversion in isolable polypyridylruthenium(II) complexes

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.

Radiocesium distribution and mid-term dynamics in the ponds of the Fukushima Dai-ichi nuclear power plant exclusion zone in 2015-2019

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 K_d(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 K_d(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, RIP^ex(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, RIP^ex(K) was on the average 2050 mEq/kg, which is within the range of values measured in laboratory studies reported in the literature.

Effects of Chemically-Modified Polypyridyl Ligands on the Structural and Redox Properties of Tricarbonylmanganese(I) Complexes

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.

Radiocesium concentrations and GPS-coupled dosimetry in Fukushima snakes

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.

Synthesis and crystal structures of manganese(I) carbonyl complexes bearing ester-substituted α-di-imine ligands

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.

Selective synthesis and crystal structures of manganese(I) complexes with a bi- or tridentate terpyridine ligand

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.

P5593The association of recurrence and bleeding events with mortality after venous thromboembolism: from the COMMAND VTE Registry

Background/Introduction

Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), has a long-term risk for recurrence, which can be prevented by anticoagulation therapy. The duration of anticoagulation therapy after VTE should be based on the balance between risks of recurrent VTE and bleeding. However, there is uncertainty about the impact of these events on subsequent mortality.

Purpose

We sought to evaluate the impact of recurrent VTE events and bleeding events on subsequent mortality in patients with VTE in a large retrospective observational database in Japan.

Methods

We evaluated the association of recurrent VTE and major bleeding with mortality among 3026 patients in the COMMAND VTE Registry. We estimated the risks of recurrent VTE events and major bleeding events for subsequent all-cause death with the multivariable Cox proportional hazard model. We incorporated the recurrent VTE events and major bleeding events during follow-up into the multivariable Cox model as time-updated covariates together with the clinically-relevant 16 risk-adjusting factors. We expressed the adjusted risks of each covariate as hazard ratios (HR) and their 95%confidence intervals (CI). Furthermore, to assess the risks of recurrent PE and recurrent DVT events for subsequent all-cause death respectively, we divided recurrent VTE events into recurrent PE (PE with or without DVT) and recurrent DVT (DVT only), and incorporated these events as well as major bleeding events into the multivariable Cox model as time-updated covariates.

Results

In the current study population, the mean age was 67 years, 61% were women, and mean body weight and body mass index were 57.9 kg and 23.2 kg/m2, respectively. During the median follow-up period of 1,218 days, 763 patients died, 225 patients developed recurrent VTE events, and 274 patients developed major bleeding events. The time-updated multivariable Cox proportional hazard model revealed that both the recurrent VTE events and the major bleeding events were strongly associated with subsequent mortality risk (recurrent VTE events: HR 3.24, 95% CI 2.57–4.08, P<0.001; major bleeding events: HR 3.53, 95% CI 2.88–4.31, P<0.001). Both the recurrent PE events and the recurrent DVT events were associated with subsequent mortality risk with the numerically greater magnitude of effect with the recurrent PE events than with the recurrent DVT events (recurrent PE events: HR 4.42, 95% CI 3.28–5.95, P<0.001; recurrent DVT events: HR 2.42, 95% CI 1.75–3.36, P<0.001).

Conclusions

In the real-world patients with VTE, both recurrent VTE events and major bleeding events were strongly associated with subsequent mortality risk with the comparable effect size. Recurrent PE and recurrent DVT events were also associated with increased risks for mortality, although the magnitude of the effect on mortality was numerically greater with the recurrent PE events than with the recurrent DVT events.

Acknowledgement/Funding

Research Institute for Production Development, Mitsubishi Tanabe Pharma Corporation

P3389Angioscopic differences in quality and quantity of neointima in patients experiencing an acute coronary syndrome treated with bare metal, first-, second-, and third generation drug-eluting stents

Background

Although drug-eluting stents (DES) have substantially reduced the need for early target lesion revascularization (TLR) compared with bare-metal stents (BMS) by inhibiting neointima hyperplasia, early generation DES have been associated with an increased risk of very late stent failure (VLSF) due to stent thrombosis and TLR after 1 year. Although the incidence of VLSF is reduced with newer generation DES, VLSF remains an unresolved problem and its mechanisms are not fully explored.

Purpose

The purpose of this study was to evaluate quality and quantity of neointima and presence of thrombus by using coronary angioscopy at long-term follow-up in patients who experienced an acute coronary syndrome (ACS) treated with BMS and DES on dual antiplatelet therapy.

Methods

Coronary angioscopy was performed at 6 and 10 months after BMS and DES implantation, respectively, in ACS patients. We assessed neointimal coverage (NC) of the stent struts, yellow color grade (YG) of stented segment and the existence of thrombus. Angioscopic NC was defined as follows: grade 0= fully visible struts; grade 1= visible struts through thin neointima; grade 2= no visible struts. We determined maximum (Max-NC) and minimum coverage (Min-NC) grades and the dominant NC grades. YG was classified into 4 grades (0= white; 1= slight yellow; 2= yellow; 3= intensive yellow). The obtained findings were compared with BMS, first-generation (1st-) DES, second-generation (2nd-) DES and third-generation (3rd-) DES.

Results

A total of 212 patients were enrolled: BMS (n=127), 1st DES (n=26, sirolimus-eluting stent), 2nd-DES (n=38, permanent polymer everolimus-eluting stent), and 3rd-DES (n=21, bioresorbable polymer everolimus-eluting stent). Max-NC and Min-NC grade were significantly lower with 1st- and 2nd-DES than with BMS and 3rd-DES (Figure). The same trend was also observed in the dominant NC grades. There was a lower trend of YG in BMS and 3rd-DES than in 1st or 2nd-DES (Figure). The presence of thrombus was significantly lower in 3rd-DES in comparison with BMS, 1st-, and 2nd-DES (3rd-DES 0%, BMS 20.5%, 1st-DES 24%, 2nd-DES 13.5%, P=0.01).

Figure 1

Conclusion

Patients treated with 3rd-DES have higher NC grade, lower incidence of intrastent thrombus, and lower YG than in 1st and 2nd-DES. These findings may explain the lower incidence of VLSF associated with these newer generation stent platforms.

P3847Deep vein thrombosis in upper extremities: clinical characteristics, management strategies and long-term outcomes from the COMMAND VTE Registry

Background/Introduction

Pulmonary embolism (PE) is caused by blockage of pulmonary arteries by thrombus. The sources of thrombus are thought to be mostly veins in lower extremities, whereas deep vein thrombosis (DVT) in upper extremities rarely occurs spontaneously. Recent studies reported that DVT in upper extremities might have significant complications, and DVT in upper extremities could be increasing. However, there is a paucity of data on patients with DVT in upper extremities, leading to uncertainty in optimal treatment strategies including anticoagulation therapy.

Purpose

We sought to evaluate the clinical characteristics, management strategies, and long-term outcomes of patients with DVT in upper extremities in a large observational database in Japan.

Methods

The COMMAND VTE Registry is a multicenter registry enrolling 3027 consecutive patients with acute symptomatic venous thromboembolism (VTE) objectively confirmed by imaging examination or by autopsy among 29 centers in Japan between January 2010 and August 2014. The current study population consisted of 2498 patients with DVT in upper or lower extremities, after excluding 381 patients with PE only, 144 patients who had thrombus in locations other than upper or lower extremities, and 4 patients with DVT in both upper and lower extremities. The study patients were divided into 2 groups: patients with DVT in upper extremities and patients with DVT in lower extremities. We compared the clinical characteristics, management strategies and long-term outcomes between the 2 groups.

Results

There were 74 patients (3.0%) with upper extremities DVT and 2498 patients (97%) with lower extremities DVT. Patients with upper extremities DVT more often had active cancer at diagnosis (58%) and central venous catheter use (22%). The proportion of concomitant PE at diagnosis was lower in patients with upper extremities DVT than in those with lower extremities DVT (14% and 51%, P<0.001). Discontinuation of anticoagulation therapy was more frequent in patients with upper extremities DVT (63.8% and 29.8% at 1-year, P<0.001). The cumulative 3-year incidence of recurrent VTE was not different between the 2 groups (9.8% and 7.4%, P=0.43) (Figure). After adjusting confounders, the risks of upper extremities DVT relative to lower extremities DVT for recurrent VTE remained insignificant (HR 0.94, 95% CI 0.36–2.01, P=0.89).

Kaplan-Meier event curves for recurrence

Conclusions

The prevalence of patients with DVT in upper extremities was 3.0% in the current large-scale real-world registry. Patients with DVT in upper extremities more often had active cancer at diagnosis and central venous catheter use as a transient risk factor for VTE, and less often had concomitant PE. Patients with DVT in upper extremities had similar long-term risk for recurrent VTE as those with DVT in lower extremities despite shorter duration of anticoagulation.

Acknowledgement/Funding

Research Institute for Production Development, Mitsubishi Tanabe Pharma Corporation

P3846The association between statin prescription, recurrent venous thromboembolism and bleeding events: from the COMMAND VTE Registry

Background

Statin prevents occurrence and recurrence of atherosclerotic events. With regard to venous thromboembolism (VTE), a randomized controlled trial suggested that statin reduced occurrence of VTE, whereas its usefulness as secondary prevention of VTE remains to be elucidated.

Purpose

This study aimed to assess the association between statin prescription, recurrent VTE and bleeding events in patients with VTE.

Methods

The COMMAND VTE Registry is a multicentre registry enrolling consecutive 3027 patients with acute symptomatic VTE among 29 centres in Japan. We divided the cohort into the patients who were prescribed statin (N=437) and those not (N=2590), and compared the two groups. We assessed hazard ratios (HRs) of those with statin relative to those without for long-term clinical outcomes (recurrent symptomatic VTE and International Society of Thrombosis and Hemostasis [ISTH] major bleeding). Because the durations of anticoagulation therapy were widely different between the two groups, we constructed Cox's proportional hazard model incorporating status of anticoagulation during the follow-up period as a time-varying covariate. Also, because the incidences of death were strikingly different between the two groups due to the difference in the prevalence of active cancer, we used Fine-Gray's subdistribution hazard model in the presence of competing risks. We incorporated clinically relevant factors into these two models as covariates (10 factors for recurrent VTE and 11 for major bleeding).

Results

The statin group was significantly older than the non-statin group (statin 71.2±11.8 vs. non-statin 66.5±15.8, P<0.001). The prevalence of active cancer in the statin group was less than one-half of that in the non-statin group (12% vs. 25%, P<0.001), and the cumulative 3-year incidence of death was significantly lower in the statin group than in the non-statin group (12.8% vs. 26.1%, log-rank P<0.001). The table shows the adjusted HRs of the statin group relative to the non-statin group. The HRs of the statin group relative to non-statin group for recurrent VTE were significantly low, but those for major bleeding were insignificant.

Adjusted hazard ratios Outcome measures Model 1 P value Model 2 P value Adjusted HR [95% CI] Adjusted HR [95% CI] Recurrent VTE 0.59 [0.36–0.98] 0.042 0.53 [0.32–0.89] 0.02 Major bleeding 0.87 [0.60–1.24] 0.43 0.997 [0.69–1.43] 0.99 Model 1 derived from Cox's model with time-varying covariate of anticoagulation status. Model 2 derived from Fine-Gray's model.

Study flowchart

Conclusions

Prescription of satin was associated with significantly low risks for recurrent VTE, whereas that was not for major bleeding events. Statin could be a potential treatment option for secondary prevention of VTE.

P5592Thrombolysis with tissue plasminogen activator for patients with acute pulmonary embolisms in the real world: from the COMMAND VTE Registry

Background/Introduction

There is still uncertainty about the optimal usage of thrombolysis for acute pulmonary embolisms (PEs), leading to widely varying usage of thrombolysis in the real world. However, these have not been fully evaluated yet.

Purpose

We sought to evaluate the management strategies and clinical outcomes of thrombolysis for acute PEs in the real world.

Methods

The COMMAND VTE Registry is a multicenter registry enrolling 3,027 consecutive patients with acute symptomatic venous thromboembolisms in Japan between January 2010 and August 2014. The present study population consisted of 1,549 patients with PEs who received tissue plasminogen activator (t-PA) thrombolysis (N=180, 12%), or those who did not (N=1,369). The effectiveness outcome was all-cause death. The safety outcome was major bleeding. We used a multivariable logistic regression analysis to estimate the odds ratio (OR) and 95% confidence intervals (CI), to adjust clinically relevant confounders (age, sex, history of major bleeding, active cancer, and anemia). Additionally, we conducted stratified analysis by clinical severity, and we also evaluated clinical outcomes according to dosages of t-PA.

Results

Patients with t-PA thrombolysis were younger, and more frequently had higher body weight, but less frequently had active cancer, history of major bleeding, and anemia. More than half of patients with t-PA thrombolysis were patients with mild PEs, and the proportions of t-PA thrombolysis varied widely across the participating centers. More than half of patients received low-dose of t-PA (<20,000 IU/kg). As for the effectiveness, 9 (5.0%) patients in the t-PA thrombolysis group and 95 (6.9%) patients in the non t-PA thrombolysis group died at 30 days (Crude OR, 0.71; 95% CI 0.35–1.42, P=0.33). As for the safety, 7 (3.9%) patients in the t-PA thrombolysis group and 22 (1.6%) patients in the non t-PA thrombolysis group experienced major bleeding events at 10 days (Crude OR, 2.48; 95% CI 1.04–5.88, P=0.04). T-PA thrombolysis group had a significantly higher risk for 10-day major bleeding (Adjusted OR, 4.01; 95% CI 1.57–10.2, P=0.004), but not a lower risk for 30-day mortality (Adjusted OR, 1.10; 95% CI 0.53–2.28, P=0.79), although the risk for 30-day mortality was significantly lower in those with severe PEs (Adjusted OR, 0.36; 95% CI 0.15–0.88, P=0.02). After adjusting confounders, the 10-day major bleeding risk of the low-dose of t-PA group relative to the standard-dose of t-PA group tended to be lower (Adjusted OR, 0.07; 95% CI 0.004–1.05, P=0.05).

Conclusions

In the present real-world registry, relatively large number of patients received t-PA thrombolysis with wide variation across the participating centers. T-PA thrombolysis was significantly associated with a higher risk for major bleeding, but not a lower risk for mortality, although there appeared to be a benefit of t-PA thrombolysis in decreasing the risk for mortality in patients with severe PEs.

Acknowledgement/Funding

Research Institute for Production Development, Mitsubishi Tanabe Pharma Corporation

P6461The long-term clinical comparisons of symptomatic patients of pulmonary embolism with and those without deep vein thrombosis: from the COMMAND VTE Registry

Background

Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), has significant morbidity and mortality. Acute PE, in particular, is fatal if we miss it, and symptomatic patients of PE sometimes have concomitant DVT.

Purpose

This study compared the risk of mortality in symptomatic patients of PE with and those without DVT in the long term.

Methods

The COMMAND VTE Registry is a multicenter registry enrolling consecutive 3027 patients with acute symptomatic VTE objectively confirmed by imaging examination or by autopsy among 29 centers in Japan between January 2010 and August 2014. Patients with both PE and DVT (N=1334) were regarded as PE patients, and the current study population consisted of 1715 PE patients and 1312 DVT patients.

Results

There were 1203 symptomatic patients of PE, including 381 without and 822 with DVT. In our cohort, the mean age was 67.9±14.9 years, 63% was female, 44% had hypertension, 12% diabetes mellitus, 5% history of VTE. There were 20% of active cancer. Baseline characteristics were well matched except for dyslipidemia (18% vs. 23%, p=0.021) and atrial fibrillation (8% vs. 5%, p=0.045). Patients without DVT had a more severe clinical presentation compared to those with DVT, including hypoxemia, shock and arrest. Moreover, Initial parenteral anticoagulation therapy in the acute phase was administered less frequently in patients without DVT (89% vs. 96%, P=0.0001). Two groups received thrombolysis (20% vs. 26%, P=0.18) and mechanical supports (Ventilator 14% vs. 5%, p<0.001, PCPS 5% vs. 3%, p<0.001, respectively). During follow-up, 93 (8%) patients experienced recurrent VTE events and 98 (8%) major bleeding events, and 323 (27%) patients died. The most frequent cause of death was cancer (11%). There were a significant differences in the cumulative incidences of all-cause death between the groups (32% vs. 24%, P=0.006), whereas there was significant difference in VTE-related death (13% vs. 4%, p<0.001). Estimated freedom rates from death for patients of PE without and those with DVT were as follows: 88% vs 99% at 10-day, 86% vs 95% at 1-month, 75% vs 83% at 1-year, and 64% vs 71% at 5-year, respectively.

Landmark analysis

Conclusions

In symptomatic patients of PE, there was a difference in mortality between groups, but no difference in recurrent VTE. Patients without DVT had a more severe clinical presentation compared to those with DVT, and many VTE-related deaths in the acute phase. The one-month mortality rate differed statistically between groups, but there was no significant difference in long-term survival beyond one month. Most of deaths were due to underlying diseases, mainly cancer, and less commonly due to VTE in the long term.

Acknowledgement/Funding

Research Institute for Production Development, Mitsubishi Tanabe Pharma Corporation

P2770Clinical characteristics and outcomes of venous thromboembolism according to patients with versus without atrial fibrillation: from the COMMAND VTE Registry

Background/Introduction

Oral anticoagulants are widely used for the treatment and second prevention of venous thromboembolism (VTE) and stroke prevention in atrial fibrillation (AF). VTE and AF are common diseases and these sometimes might coexist. However, there are few reports about the relationship between VTE and AF.

Purpose

We sought to evaluate the clinical characteristics and outcomes in VTE patients with AF.

Methods

The COMMAND VTE Registry is a multicenter registry enrolling consecutive 3027 patients with acute symptomatic VTE objectively confirmed by imaging examination or by autopsy among 29 centers in Japan between January 2010 and August 2014. The current study population consisted of 129 patients with AF (AF group) and 2898 patients without AF (non-AF group). We compared the clinical characteristics, management strategies and long-term outcomes between the 2 groups.

Results

The AF group was older (mean age: 75.3 vs. 66.8 years, P<0.001), and more often had co-morbidities such as hypertension (54.3% vs. 37.7%, P<0.001), diabetes mellitus (20.2% vs. 12.4%, P=0.01), chronic kidney disease (28.7% vs. 18.5%, P=0.004), heart failure (28.7% vs. 18.5%, P=0.004), history of stroke (20.2% vs. 8.4%, P<0.001), and history of major bleeding (12.4% vs. 7.4%, P=0.04) compared with the non-AF group, whereas there were no significant differences in the proportions of active cancer at diagnosis (18.6% vs. 23.2%, P=0.23) and pulmonary embolism at presentation (64.3% vs. 56.3%, P=0.07). The proportion of anticoagulation therapy beyond acute phase was not significantly different (94% vs. 93%, P=0.60), while the cumulative discontinuation rates of anticoagulation therapy was significantly lower in the AF group (26.9% vs. 43.4% at 3 years, Log-rank P=0.03). The cumulative 5-year incidences of recurrent VTE and major bleeding were not significantly different (Recurrent VTE: 7.6% vs. 10.6%, Log-rank P=0.89; Major bleeding: 18.6% vs. 11.8%, Log-rank P=0.07). After adjusting for potential confounders, the risks of the AF group relative to the non-AF group for recurrent VTE and major bleeding remained insignificant (HR 1.19, 95% CI 0.54–2.28, P=0.64; HR 1.28, 95% CI 0.73–2.06, P=0.37). The cumulative 5-year incidence of all-cause death was significantly higher in the AF-group (49.1% vs. 28.6%, Log-rank P<0.001). After adjusting for potential confounders, the risks of the AF group relative to the non-AF group for all-cause death remained significant (HR 1.63, 95% CI 1.23–2.15, P<0.001). The proportion of deaths due to cancer was lower in the AF group (30% vs. 55%, P<0.001), while the proportion of cardiac deaths was higher in the AF group (16.1% vs. 4.0%, P<0.001).

The outcomes of VTE patients with AF

Conclusions

The risks for recurrent VTE between patients with AF and those without AF were not significantly different, although patients with AF received longer-term anticoagulation therapy, whereas the risks for major bleeding tended to be higher in patients with AF.

Acknowledgement/Funding

Research Institute for Production Development, Mitsubishi Tanabe Pharma Corporation

Formation and stability of the mixed-chelator complexes of Sr2+, Mg2+, Ca2+, Ba2+, and Y3+ in solution with bio-relevant chelators

The formation and equilibria of Sr²⁺, Mg²⁺, Ca²⁺, Ba²⁺, and Y³⁺ (M) complexes with a mixed-chelator comprising two biodegradable chelators (GLDA, L_G, 2-[bis(carboxymethyl)amino] pentanedioic acid; HIDS, L_H, 2-(1,2-dicarboxyethylamino)-3-hydroxy-butanedioic acid) in an aqueous matrix was evaluated. The potentiometric measurement results (ionic strength, 0.10 M; temperature, 25 ± 0.1 °C) confirmed the formation of 1:1:1 (M:L_G:L_H) complexes and the experimental data sets were further used to derive the equilibrium constants for the ternary complexes. The [MHL_GL_H]^5- complex was the dominant ternary complex with Sr²⁺, Mg²⁺, Ca²⁺, and Ba²⁺, while Y³⁺ formed [M(OH)₂L_GL_H]^7- as the principal ternary species. The trend in the overall formation constants of the ML_mix (L_mix, L_G:L_H = 1:1) complexes was in the order: Y³⁺ > Ca²⁺ > Mg²⁺ > Sr²⁺ > Ba²⁺. The ternary complexation trend was interpreted using the corresponding atomic radii and solution-phase electronegativities of the elements. The modes of interaction between the chelators and cations in the ML_mix systems were subsequently deduced, and evaluated by using Gaussian 16W program. The relative stabilities of the ternary complexes (ΔlogK) were interpreted by comparison with the stabilities of the corresponding binaries, with negative ΔlogK values observed for all the ML_mix complexes.

A comparison of methods to derive aggregated transfer factors using wild boar data from the Fukushima Prefecture

Aggregated transfer factors (T_ag; m² kg^-1) are often used to predict radionuclide activity concentrations in biota (Bq kg^-1) from soil contamination levels (Bq m^-2). Inherently large uncertainties in T_ag values severely limit their predictive power. Many published T_ag values have been derived from radionuclide deposition onto soil following weapons fallout, or the accidents at Chernobyl and Fukushima. In many cases the soil data used to derive a T_ag value were collected for other purposes, and the spatial resolution of the soil data is much less than that of the biota data to which it is paired. We hypothesized that this disassociation and imprecision in paring deposition density and biota data may contribute to the large variations observed in T_ag values. We tested the hypothesis by deriving T_ag values for Japanese wild boar in two ways. One method used paired deposition density-biota contamination levels, with the soil data collected from each boar trap site. The second method used a soil radioactivity density map, of relatively low spatial resolution, generated by the Japanese government agency MEXT for fallout from the Fukushima accident. We hypothesized that T_ag values derived from the method using paired deposition density-wild boar data would have less variation. Initial statistical test suggested significant differences in the predictive power of the two methods. However, removal of suspected outliers in the MEXT data set decreased the statistical differences and indicated that collecting ¹³⁷Cs soil deposition density measurements in the field did not reduce the large variation in our T_ag values. More importantly, both methods revealed that soil contamination levels are a poor predictor of radiocesium concentrations in boar (r² < 0.23). The inadequacies of T_ag to predict wild boar ¹³⁷Cs concentrations is an ominous indication of the lack of applicability of the T_ag model as a rigorous research parameter. T_ag values are best suited for their original intended purpose: upper tier, screening level computations. Further studies on how to reduce uncertainty when predicting ¹³⁷Cs concentrations in biota are needed to thoroughly understand the transfer of radiocesium within the environment.

fac-Bromido/chlorido(0.50/0.50)[3-carbamoyl-1-(1,10-phenanthrolin-2-ylmethyl)pyridinium-κ2 N,N′]tricarbonylmanganese(I) 0.49-bromide 0.51-chloride methanol monosolvate

The title complex, [MnBr0.50Cl0.50(C19H15N4O)(CO)3]Br0.49Cl0.51·CH3OH, exhibits substitutional disorder of the halogen ligand in the asymmetric unit, with almost the same occupancies for Br and Cl. The MnI atom is coordinated in a distorted octahedral environment by three carbonyl C atoms, the disordered X − ligand (X = Br or Cl) and two N atoms from the 1,10-phenanthroline ligand bearing a nicotinamide pendant moiety. The cation displays a fac configuration of the carbonyl ligands. There is another disorder between the chloride ligand and its trans-situated carbonyl ligand, and between Cl− and Br− at the position of the counter-anion. In the crystal, intermolecular C—H...X, N—H...X, O—H...X (X = Br or Cl) and C—H...O hydrogen bonds lead to the formation of a three-dimensional network.

Use of different surface covering materials to enhance removal of radiocaesium in plants and upper soil from orchards in Fukushima prefecture

The effectiveness of a decontamination methodology whereby herbaceous plants were grown through different materials covering the soil surface followed by subsequent removal of the material, associated plant tissues and attached soil on ¹³⁷Cs removal from soil was evaluated. Revegetation netting sown with Kentucky bluegrass and white clover had a high effectiveness in ¹³⁷Cs removal when rolling up the plants, roots, and rhizosphere soil approximately 6 months after sowing. The removal rate was lower when there was higher ¹³⁷Cs vertical migration down the soil profile. The maximum removal effectiveness of 93.1% was observed by rolling up fertilized Kentucky bluegrass with a well-developed root mat without netting, indicating that applying nutrients to encourage the development of roots or root mats in the 3 cm topsoil rhizosphere is an efficient technology to increase the decontamination effect of plant removal in orchards. Netting and weeding were able to remove up to 80% of ¹³⁷Cs in the soil without the use of heavy machinery. There was a significant relationship between the removal ratio and the removed soil weight per area. Using the relationship on the site below the canopy, removal of 14.3 kg m^-2 DW soil would achieve a removal ratio of 80%. The effectiveness of the technique will decrease with time as radiocaesium migrates down the soil profile but this would be expected to occur slowly in many soils.

Crystal structure of a dinuclear ruthenium(II) complex with a bent CO22- bridge

The mol-ecular and crystal structures of a CO22--bridged dinuclear ruthenium complex is reported, namely, μ-carbonito-κ2C:O-bis-[bis(2,2'-bi-pyridine-κ2N,N')carbon-ylruthenium(II)] bis-(hexa-fluorido-phosphate)-aceto-nitrile-diethyl ether (1/1/0.5), [Ru2(CO)2(C10H8N2)4(μ:κ2-C:O-CO2)](PF6)2·CH3CN·0.5C4H10O. The complex cation in the title compound consists of two {Ru(CO)(bpy)2}2+ units (bpy = 2,2'-bi-pyridine) singly bridged by a μ:κ2-C:O carbonite anion, resulting in an unsymmetrical dinuclear structure. Some of the inter-atomic C⋯O distances involving the carbonyl ligands are shorter than the sum of the van der Waals radii. There are intra-molecular C-H⋯O and aromatic π-π contacts in the cationic complex. In the crystal, the cations are linked by pairs of C-H⋯F hydrogen bonds in addition to weak C-H⋯F inter-actions between the solvent mol-ecules and PF6- counter-anions. The equatorial F atoms of one of the PF6- anions are disordered over two sets of sites with an occupancy ratio of 0.908 (7):0.092 (7) while the central O atom of the diethyl ether solvent mol-ecule is disordered over an inversion centre.

Relationships of Plasma Viscosity, Coagulation and Fibrinolysis to Coronary Risk Factors and Angina

Plasma viscosity, molecular markers of activated coagulation and fibrinolysis (fibrinopeptides A and Bβ15-42), coagulation factors (fibrinogen and factor VII) and antiplasmins were measured in 529 men aged 35-54 years and related to new angina pectoris (n = 117) and to coronary risk factors in controls without angina (n = 412). Five major risk factors (cigarette-smoking, blood pressure, cholesterol, triglyceride and body mass index) were each associated with increases in plasma viscosity, coagulation factors, and imbalance of coagulation over fibrinolysis (increased ratio of fibrinopeptide A/fibrinopeptide Bβ15-42). Increased viscosity and fibrinogen in smokers were partly reversed in exsmokers, but the imbalance of coagulation and fibrinolysis persisted. Cholesterol and triglyceride were also associated with increased antiplasmin activity. In men with angina, only fibrinogen was elevated compared to controls. We suggest that increased plasma viscosity and an imbalance of coagulation over fibrinolysis may be mechanisms by which known risk factors promote arterial thrombosis, but are not present in stable angina.

Radioactive and stable cesium isotope distributions and dynamics in Japanese cedar forests

Dynamics of the Fukushima-derived radiocesium and distribution of the natural stable isotope ¹³³Cs in Japanese cedar (Cryptomeria japonica D. Don) forest ecosystems were studied during 2014-2016. For the experimental site in Yamakiya, Fukushima Prefecture, we present the redistribution of radiocesium among ecosystem compartments during the entire observation period, while the results obtained at another two experimental site were used to demonstrate similarity of the main trends in the Japanese forest ecosystems. Our observations at the Yamakiya site revealed significant redistribution of radiocesium between the ecosystem compartments during 2014-2016. During this same period radionuclide inventories in the aboveground tree biomass were relatively stable, however, radiocesium in forest litter decreased from 20 ± 11% of the total deposition in 2014 to 4.6 ± 2.7% in 2016. Radiocesium in the soil profile accumulated in the 5-cm topsoil layers. In 2016, more than 80% of the total radionuclide deposition in the ecosystem resided in the 5-cm topsoil layer. The radiocesium distribution between the aboveground biomass compartments at Yamakiya during 2014-2016 was gradually approaching a quasi-equilibrium distribution with stable cesium. Strong correlations of radioactive and stable cesium isotope concentrations in all compartments of the ecosystem have not been reached yet. However, in some compartments the correlation is already strong. An increase of radiocesium concentrations in young foliage in 2016, compared to 2015, and an increase in 2015-2016 of the ¹³⁷Cs/¹³³Cs concentration ratio in the biomass compartments with strong correlations indicate an increase in root uptake of radiocesium from the soil profile. Mass balance of the radionuclide inventories, and accounting for radiocesium fluxes in litterfall, throughfall and stemflow, enabled a rough estimate of the annual radiocesium root uptake flux as 2 ± 1% of the total inventory in the ecosystem.

Natural attenuation of Fukushima-derived radiocesium in soils due to its vertical and lateral migration

Processes of vertical and lateral migration lead to gradual reduction in contamination of catchment soil, particularly its top layer. The reduction can be considered as natural attenuation. This, in turn, results in a gradual decrease of radiocesium activity concentrations in the surface runoff and river water, in both dissolved and particulate forms. The purpose of this research is to study the dynamics of Fukushima-derived radiocesium in undisturbed soils and floodplain deposits exposed to erosion and sedimentation during floods. Combined observations of radiocesium vertical distribution in soil and sediment deposition on artificial lawn-grass mats on the Niida River floodplain allowed us to estimate both annual mean sediment accumulation rates and maximum sedimentation rates corresponding to an extreme flood event during Tropical Storm Etau, 6-11 September 2015. Dose rates were reduced considerably for floodplain sections with high sedimentation because the top soil layer with high radionuclide contamination was eroded and/or buried under cleaner fresh sediments produced mostly due to bank erosion and sediments movements. Rate constants of natural attenuation on the sites of the Takase River and floodplain of Niida River was found to be in range 0.2-0.4 year^-1. For the site in the lower reach of the Niida River, collimated shield dose readings from soil surfaces slightly increased during the period of observation from February to July 2016. Generally, due to more precipitation, steeper slopes, higher temperatures and increased biological activities in soils, self-purification of radioactive contamination in Fukushima associated with vertical and lateral radionuclide migration is faster than in Chernobyl. In many cases, monitored natural attenuation along with appropriate restrictions seems to be optimal option for water remediation in Fukushima contaminated areas.

Effects of bark washing and epiphytic moss on 137Cs activity concentration in bark and stemflow in Japanese persimmon (Diospyros kaki Thunb.)

The effects of bark washing, and of epiphytic moss growing on the bark surfaces, on the ¹³⁷Cs activity concentrations in bark and stemflow samples were evaluated at two Japanese persimmon orchards located in Fukushima City and Date City, both approximately 60-65 km northwest of the Fukushima Dai-ichi nuclear power plant. The means of ¹³⁷Cs in stemflow captured by 1 g of sphagnum placed on the main trunks of washed and unwashed trees, and on sites with moss and with no moss growing on bark of the non-washed trees in Date City, were 0.37 Bq, 1.08Bq, 0.77 Bq and 0.52 Bq respectively. The ¹³⁷Cs was significantly lower in the washed bark and in the absence of moss at p = 0.00031 and p = 0.0443 by t-test respectively. The ¹³⁷Cs in directly-collected stemflow on the main trunks was significantly higher for the unwashed tree at 6.0 Bq L^-1 compared with the washed tree at 1.1 Bq L^-1 (p = 0.017 by Tukey's test). The extraction rate of dissolved ¹³⁷Cs with deionized water was 7.3% even after stirring for 40 h. These results indicate that the moss acts as reservoir of ¹³⁷Cs, and that bark-washing decontamination can reduce the additional ¹³⁷Cs supply from moss in subsequent years following the radioactive fallout.

Behavior of 137Cs in ponds in the vicinity of the Fukushima Dai-ichi nuclear power plant

¹³⁷Cs activity concentration in the water of four ponds, Suzuuchi (SU), Funasawa (FS), Inkyozaka (IZ), and Kashiramori (KM), that are within 10 km of the Fukushima Dai-ichi nuclear power plant were observed from April 2015 to August 2016. ¹³⁷Cs inventories in soils surrounding SU, FS, IZ, and KM were 6.4, 2.9, 2.1, and 0.9 MBq m^-2, respectively. ¹³⁷Cs inventories in the bottom sediments of SU, FS, IZ, and KM were 13, 8.9, 1.6, and 1.1 MBq m^-2, respectively. Higher ¹³⁷Cs inventories in bottom sediment than those of soil in SU and FS suggest that ¹³⁷Cs was delivered to and accumulated in these ponds. Mean total ¹³⁷Cs activity concentrations in SU, FS, IZ, and KM were 41, 13, 9.5, and 1.4 Bq L^-1, respectively. Particulate ¹³⁷Cs concentration accounted for 71-90% of total ¹³⁷Cs in the water samples, on average. The mean distribution coefficient, K_d, in SU, FS, IZ, and KM was 1.3 × 10⁵, 2.1 × 10⁵, 1.7 × 10⁵, and 6.2 × 10⁵ L kg^-1, respectively. These K_d values were higher than the K_d values observed in the Chernobyl area by 1-2 orders of magnitude. Although no significant decreasing trends were found, dissolved ¹³⁷Cs activity concentration tended to be low during winter in all four ponds. Dissolved ¹³⁷Cs activity concentrations were proportional to K⁺ and DOC concentrations in all the ponds. The results from principal component analysis performed for ¹³⁷Cs activity concentration and water chemistry data sets suggested that there were different mechanisms behind variability of dissolved ¹³⁷Cs activity concentrations for each pond. Continuous monitoring is required to reveal temporal trends in ¹³⁷Cs activity concentrations of these waters and controlling factors of such in closed water systems in Fukushima.

2-(Pyridin-2-yl)-1,8-naphthyridine

The title compound, C13H9N3, has three symmetry-independent molecules in the asymmetric unit. The dihedral angles between the naphthyridine ring system and the pyridine group are in the range 3.927 (4)–7.362 (4)°. In the crystal, C—H...N interactions and aromatic π–π stacking [centroid–centroid distances = 3.5755 (7) and 3.6544 (7) Å] generate a three-dimensional network.

2-(Pyridin-2-yl)pyridinium trifluoromethanesulfonate

Although in the title salt, C10H9N2+·CF3SO3−, the C—C and C—N bond lengths within the aromatic rings are normal, there is a considerable difference in the C—N—C angles at the protonated and unprotonated N atoms,viz. 123.42 (10) and 117.10 (11)°, respectively. Bifurcated N—H...X(X= N or O) hydrogen bonds form within the cation and between cation and anion. As a result, the cation exists in acisconformation in the solid state. An obvious π–π contact is also present between the non-protonated pyridyl rings of neighbouring cations.

cis,trans-Dicarbonyldichlorido(1,10-phenanthroline-5,6-dione-κ2N,N′)ruthenium(II)

In the title compound, [RuCl2(C12H6N2O2)(CO)2], the RuIIatom (site symmetry ..2) adopts a distorted octahedral coordination sphere defined by two carbonyl C atoms, two Cl−anions and two N atoms from the chelating 1,10-phenanthroline-5,6-dione (phendione) ligand. The carbonyl ligands arecisto each other, while the Cl atoms aretrans. In the phendione ligand, the C=O [1.239 (5) Å] and the C—C [1.537 (5) Å] bond lengths in the diketone moiety have typical values. In the crystal, C—H...Cl and C—H...O hydrogen bonds lead to the formation of a three-dimensional supramolecular network.