Sewage sludge ash contaminated with radiocesium: Solidification with alkaline-reacted metakaolinite (geopolymer) and Portland cement.

This study contributes toward developing measures for the disposal of radiocesium-contaminated sewage sludge ash (SSA). Here, we prepared two types of solidified bodies containing 30 wt% radiocesium-bearing SSA. The material used for the two solidified bodies were alkaline-reacted metakaolinite (geopolymer) and ordinary Portland cement (OPC). Cement has been used for solidification of low-level radioactive wastes, and geopolymer is a candidate of cement alternative materials. The characteristics of these solidified bodies were investigated by various aspects including mechanical strength, transformation of SSA components during solidification, and radiocesium confinement ability by leaching test. The compressive strength of geopolymer- and OPC-solidified bodies at 30 wt% SSA content was more than 40 MPa. After static leaching test at 60 °C, 137Cs was hardly leached out from the geopolymer-solidified bodies containing SSA at 30 wt% to ultrapure water (<0.1%), whereas more than 30% 137Cs was leached from the OPC-solidified bodies containing SSA at 30 wt% even though only ~9% of 137Cs in the SSA is soluble. These results strongly indicate that geopolymer is far superior to OPC for solidifying radiocesium-bearing SSA.

Radiocesium in Shiitake mushroom: Accumulation in living fruit bodies and leaching from dead fruit bodies.

In this paper, cesium (Cs) accumulation by the saprophytic fungus Lentinula edodes (Shiitake) was investigated to contribute to the elucidation of radiocesium-cycling mechanisms in forest environments. Although the 137Cs in the mushroom bed before culture was bioavailable, the transfer factor (TF) of Cs (133Cs and 137Cs) from the mushroom bed to fruit bodies was low (approximately 1) and the TFs of K (5) and Na (1.5) were higher. Cs and K concentrations in fruit bodies at different maturity stages were almost constant. The concentration ratio of Cs/K is constant in the pileus regardless of the pileus tissues. These results demonstrate that Shiitake non-specifically accumulates Cs while accumulating the essential element K and provide evidence that no selective Cs accumulation (or binding) sites exist within the Shiitake fruit body. Furthermore, the present results show that most accumulated Cs quickly leaches out from the dead fruit body with exposure to water. The leached Cs was largely adsorbable on clay minerals, suggesting that the Shiitake fruit body likely contains Cs in the cation form.

Effect of bacterial siderophore on cesium dissolution from biotite.

In this study, the adsorption of cesium (Cs) on biotite and dissolution of Cs from Cs-bearing biotite using a siderophore were investigated aiming to contribute to the elucidation of radiocesium migration mechanisms in the soil environment. Thus, a siderophore was extracted and purified from the culture medium of Pseudomonas sp., and the purified siderophore was used in five consecutive dissolution experiments of biotite samples. Prior to the dissolution experiments, Cs was adsorbed on a hardly weathered biotite powder sample. The major components of the biotite (Al, Fe, and Mg) were dissolved almost stoichiometrically, strongly suggesting that the siderophore selectively dissolves the broken edges of the biotite. The amount of the dissolved Cs decreased by increasing the repetition times of the dissolution experiment. Therefore, the Cs adsorbed on the broken edges was dissolved rapidly as the siderophore dissolved the broken edges, and then, the Cs adsorbed on the outer planar surface of the biotite particles was slowly dissolved because the siderophore did not directly dissolve the outer planar surface of the biotite but dissolved the surface edge.

Role of filamentous fungi in migration of radioactive cesium in the Fukushima forest soil environment.

The fate of radioactive Cs deposited after the Fukushima nuclear power plant accident and its associated radiological impacts are largely dependent on its mobility from surface soils to forest ecosystems. We measured the accumulation of radioactive Cs in the fruit bodies of wild fungi in a forest at Iitate, Fukushima, Japan. The transfer factors (TFs) of radioactive Cs from soil to the fruit bodies of wild fungi were between 10-2 and 102, a range similar to that reported for the fruit bodies collected in Europe after the Chernobyl accident and in parts of Japan contaminated by the nuclear bomb test fallout. Comparison of the TFs of wild mushroom and those of fungal hyphae of 704 stock strains grown on agar medium containing nutrients and 137Cs showed that the TFs of wild mushroom were lower. The TF was less than 0.1 after the addition of the minerals zeolite, vermiculite, phlogopite, smectite, or illite of 1.0% weight to the agar medium. These results indicate that the presence of minerals decreases Cs uptake by fungi grown on the agar medium, and filamentous fungi still accumulate radioactive Cs even when minerals are present in the medium.

Complexation of Eu(III), Pb(II), and U(VI) with a Paramecium glycoprotein: Microbial transformation of heavy elements in the aquatic environment.

This study investigated the interaction of inorganic aqueous Eu(III), Pb(II), and U(VI) with Paramecium sp., a representative single-celled protozoan that lives in freshwater. Living and prekilled Paramecium cells were tested. The prekilled cells were killed with a fixative. After 24 h exposure of the cells to inorganic aqueous solutions containing Eu(III) or U(VI), analyses by microparticle-induced X-ray emission with a focused beam (<1 µm) did not detect Eu and U in the living cells, whereas Eu and U were detected in the prekilled cells. Size exclusion chromatography coupled with on-line ultraviolet-visible detection and elemental detection by inductively coupled plasma mass spectrometry of the aqueous phases collected after the living cell experiments revealed that a fraction of the Eu, Pb, and U in the aqueous phase bound to a large (ca. 250 kDa) Paramecium biomolecule and formed a metal-organic complex. The characteristics of the biomolecule were consistent with those of the soluble glycoproteins covering the surfaces of Paramecium cells. These results show that Paramecium cells transform inorganic aqueous Eu, Pb, and U to organic complexes. This paper discusses the relation between this novel complexation and the sorption of these heavy elements on Paramecium cells.

Direct accumulation pathway of radioactive cesium to fruit-bodies of edible mushroom from contaminated wood logs.

This paper presents the accumulation process of radioactive Cs in edible mushrooms. We here first report the direct accumulation pathway of radioactive Cs from contaminated wood logs to the fruit-bodies of shiitake mushrooms through the basal portion of the stipe. In this pathway, radioactive Cs is not transported through the hyphae. This pathway results in a high accumulation of radioactive Cs in the fruit-body, more by the excess accumulation of radioactive Cs from the wood logs than that through the hyphae. We grew the fruit-bodies of Shiitake mushroom from radioactive-Cs-contaminated wood logs. The spatial distributions of radioactive Cs and Prussian blue as a tracer of interstitial water in the cross section of the wood log measured after the harvest of the fruit-body from the inoculated sawdust spawn area indicated that some fraction of the radioactive Cs and Prussian blue were transported directly to the basal portion of the stipe during the growth of the fruit-bodies.

Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.

The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite >> vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.

Radioactive fallout cesium in sewage sludge ash produced after the Fukushima Daiichi nuclear accident.

The radioactive fallout cesium (¹³7Cs) in the sewage sludge ashes (SSAs) produced in Japan after the Fukushima Daiichi Nuclear Accident was tested. Five samples of SSAs produced in 2011 and 2012 were tested. Two of the samples contained ¹³7Cs (23 and 9.6 kBq/kg, respectively) above the radioactivity criterion (8 kBq of radioactive Cs/kg of solid) for controlled landfill disposal in Japan. The mineral components of SSA are roughly divided into two groups: an HCl-soluble phase mainly composed of phosphates and oxides; and silicates, including quartz, feldspar, and clay. Both phases contained ¹³7Cs. The majority (up to 90%) of ¹³7Cs was contained in the HCl-soluble phase. Among the HCl-soluble subphases, Fe-bearing phases that were probably iron oxides were mainly responsible for ¹³7Cs retention. No positive evidence was obtained that showed that phosphate-bearing phases, which were included most in SSAs along with the silicate phase, retained ¹³7Cs. Pre-pulverizing SSAs and heating them at 95 °C in a 6 M or a concentrated aqueous HCl was the most effective method of dissolving the HCl-soluble phase. The radioactivity concentrations of ¹³7Cs in all the HCl-treatment residues were below the radioactivity criterion. This residue was mostly composed of silicates. After static leaching tests of the residue at 60 °C for 28 days, no ¹³7Cs was detected in simulated environmental water leachates (pure water and synthetic seawater), demonstrating that 137Cs in the residue is very stably immobilized in the silicates.

Endoscopic ultrasonography is useful for monitoring the tumor response of neoadjuvant chemoradiation therapy in esophageal squamous cell carcinoma.

BACKGROUND: Recently, neoadjuvant chemoradiation therapy (CRT) has been introduced for treatment of esophageal squamous cell carcinoma (ESCC). This study was performed to investigate the usefulness of endoscopic ultrasonography (EUS) in comparison with EUS findings before and after CRT, and histologic findings. METHODS: There were 33 patients with potentially resectable ESCC who underwent neoadjuvant CRT. Preoperative EUS and histologic findings were compared. EUS criteria were established on the basis of low and high echoic regions. Resected specimens were examined by hematoxylin-eosin, azan, and cytokeratin immunohistochemical staining. RESULTS: Azan and cytokeratin staining clearly delineated fibrous changes and residual tumor. Low echoic regions corresponded to residual tumor and high echoic spots corresponded to fibrosis. All 12 patients classified as grade 1 on EUS diagnosis had histologic grade 1 tumors. Nineteen of 21 cases that presented with high echo were grade 2 or 3. The prognosis according to EUS diagnosis was similar to the histologic effect. CONCLUSIONS: Preoperative EUS findings reflected the histologic effect after neoadjuvant CRT. EUS is a useful tool to assess the effect for CRT and to predict the prognosis in ESCC patients.

Chemical speciation and association of plutonium with bacteria, kaolinite clay, and their mixture.

We investigated the interactions of Pu(VI) with Bacillus subtilis, kaolinite clay, and a mixture of the two to determine and delineate the role of the microbes in regulating the environmental mobility of Pu. The bacteria, the kaolinite, and their mixture were exposed to a 4 x 10(-4) M Pu(VI) solution at pH 5.0. The amount of Pu sorbed by B. subtilis increased with time, but had not reached equilibrium in 48 h, whereas equilibrium was attained in kaolinite within 8 h. After 48 h, the oxidation state of Pu in the solutions exposed to B. subtilis and the mixture had changed to Pu-(V), whereas the oxidation state of Pu associated with B. subtilis and the mixture was Pu(IV). Exudates released from B. subtilis reduced Pu(VI) to Pu(V). In contrast, there was no change in the oxidation state of Pu in the solution or on kaolinite after exposure to Pu(VI). Scanning electron microscopy-energy dispersive spectrometry analysis indicated that most of the Pu in the mixture was associated with B. subtilis. These results suggest that Pu-(IV) is preferably sorbed to bacterial cells in the mixture and that Pu(VI) is reduced to Pu(V) and Pu(IV).

[A case of effective multidisciplinary treatment with hepatic resection for synchronous multiple liver metastases from rectal cancer].

A 56-year-old-man complained of abdominal pain, and was diagnosed as having advanced rectal cancer with synchronous multiple metastatic liver cancer (H 3) in July 1999. He underwent low anterior resection and hepatic partial resection (S 1, S 2+S 3, S 5, S 6, S 8) in August 1999. In addition, he underwent hepatic arterial infusion chemotherapy (HAI) 6 times at ADM 30 mg+5-FU 1,000 mg+MMC 16 mg between October 1999 and July 2000 for recurrent metastatic liver cancer. He has survived more than 6 years after the initial surgery. Multidisciplinary treatment with hepatic resection may well be a strategy for patients with multiple colorectal liver cancer, even though H 3 type of metastasis.

Preoperative assessment of the depth of early gastric cancer invasion by transabdominal ultrasound sonography (TUS): a comparison with endoscopic ultrasound sonography (EUS).

BACKGROUND/AIMS: Transabdominal ultrasound sonography (TUS) is considered a useful diagnostic tool ascertaining depth of cancer invasion, but there are few detailed studies on its accuracy in preoperative estimations of depth of invasion in early gastric cancer (mucosal and submucosal cancer). We retrospectively analyzed the clinical efficacy of preoperative evaluation by TUS in early gastric cancer in comparison with endoscopic ultrasound sonography (EUS). METHODOLOGY: A total of 101 patients preoperatively diagnosed as early gastric cancer were enrolled in the current study. Patients were given 300cc of water subsequent to administration of an anti-peristaltic agent to facilitate filling the gastric lesion with water and TUS was performed. All patients were preoperatively examined by both EUS and TUS. RESULTS: The depth accuracy in mucosal cancer was 59% with EUS and 66% with TUS. When submucosal cancers were subdivided into shallow and deep submucosal cancers, the depth of mucosal and shallow-submucosal (SM1) cancers were correctly assessed 80% and 78% by EUS and TUS, respectively. Accuracy increased by 12% in mucosal cancer by combining EUS and TUS diagnoses. CONCLUSIONS: The diagnostic value of TUS is comparable to that of EUS in assessing depth of invasion of early gastric cancer, however, TUS had a possibility of misdiagnosing the depth of tumors located at the anterior wall. To ensure an accurate estimation of the depth of tumor invasion, it is recommended that TUS and EUS be done simultaneously.

Endosonographic detection of mediastinal lymph node metastasis in superficial carcinoma of the esophagus: assessment by type classification and histogram.

BACKGROUND: Endoscopic ultrasonography (EUS) has been shown to be useful for detecting lymph node metastasis in esophageal cancer. The evaluation of nodal metastasis requires both objective and subjective analyses. In the present study, mediastinal lymph nodes in superficial esophageal carcinoma (SEC) were examined by both EUS appearance and histography, using NIH image software. METHODS: One hundred and seventy-one lymph nodes of 56 patients with SEC were detected by EUS. These lymph nodes were diagnosed by type classification, based on boundary and internal echo, and by the construction of internal echo histograms using NIH image software. The results were compared with the histological findings. RESULTS: . The sensitivity, specificity, and accuracy in assessing mediastinal lymph node metastasis by type classification were 83.3%, 88.2%, and 87.7%, respectively. The mean and SD of the histogram correlated well with histological findings and type classification ( P < 0.0001). All lymph nodes with a mean value of less than 185 of the histogram were negative nodes. When positive nodes by type classification were reevaluated according to the threshold value of 185 using the histogram, the sensitivity, specificity, and accuracy improved to 83.3%, 100%, and 98.2%, respectively. CONCLUSIONS: Type classification assisted by histography improved the diagnostic accuracy of mediastinal lymph node metastasis in SEC.

Novel approach for the effective determination of DNA scission site using the Sanger method.

This paper describes the effective determination of DNA scission site using a novel approach that is based on the Sanger method of nucleotide sequencing. The DNA scission site is determined by contrast with the nucleotide sequence of the DNA. Here, instead of the traditional Maxam-Gilbert method for the determination of the DNA sequence, we utilized the Sanger method and studied its effectiveness in the determination of DNA scission sites. Using this method, the determination of DNA scission site becomes more facile and exact. And the total time for the determination is reduced nearly by half in comparison to the Maxam-Gilbert method. Further advantages of this novel approach include the reduced risks of radiation exposure for researchers and contamination of the apparatus.

Biologic and imaging diagnosis of lymph node metastasis in esophageal carcinoma.

BACKGROUND AND OBJECTIVES: Few reports have described the combined use of biologic and imaging techniques in the diagnosis of lymph node metastasis. We prospectively evaluated lymph node metastasis diagnosed by biologic and imaging means in patients with esophageal carcinoma. METHODS: Preoperative ultrasound and endoscopic ultrasound (EUS) examination were performed in 80 patients. Biopsy specimens were immunohistochemically examined using cyclin D1 (CD1) and desmoglein 1 (DG1) antibodies, and tumors were classified into three grades. RESULTS: The sensitivity, specificity, and accuracy values of ultrasound examination were 88.2, 58.6, and 77.5%, respectively. The incidence of nodal involvement was 0% (0/10) in patients with grade 1 tumors, 57.1% (16/28) in those with grade 2 tumors, and 83.3% (35/42) in those with grade 3 tumors. Of the 57 patients with lymph node metastasis determined sonographically, 50 had grade 2 or 3 tumors that were histologically confirmed. The remaining seven patients with grade 1 tumors did not have involved nodes. Of the 23 patients without lymph node metastasis according to ultrasound examination, the incidence of lymph node metastasis in patients with grade 1, 2, and 3 tumors was 0, 16.7, and 50.0%, respectively. CONCLUSIONS: When used together, imaging and molecular procedures may offer improved identification of lymph node metastasis in patients with squamous cell carcinoma of the esophagus.