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Ways to reduce the duration of column percolation tests specified in ISO/TS 21268-3 were proposed.Four equilibrium periods and two flow rates on four different soils were ...tested.The time to perform column percolation tests can be shortened from 20 to 30days to 7⿿9 days.The recommended initial equilibrium period is 12⿿16h, shorten from 48h.The recommended flow rate is 36mL/h which is three times that specified in ISO/TS 21268-3.
Column percolation tests may be suitable for prediction of chemical leaching from soil and soil materials. However, compared with batch leaching tests, they are time-consuming. It is therefore important to investigate ways to shorten the tests without affecting the quality of results. In this study, we evaluate the feasibility of decreasing testing time by increasing flow rate and decreasing equilibration time compared to the conditions specified in ISO/TS 21268-3, with equilibration periods of 48h and flow rate of 12mL/h. We tested three equilibration periods (0, 12⿿16, and 48h) and two flow rates (12 and 36mL/h) on four different soils and compared the inorganic constituent releases. For soils A and D, we observed similar values for all conditions except for the 0h⿿36mL/h case. For soil B, we observed no appreciable differences between the tested conditions, while for soil C there were no consistent trends probably due to the difference in ongoing oxidation reactions between soil samples. These results suggest that column percolation tests can be shortened from 20 to 30days to 7⿿9days by decreasing the equilibration time to 12⿿16h and increasing the flow rate to 36mL/h for inorganic substances.
Up-flow column percolation tests are used at laboratory scale to assess the leaching behavior of hazardous substance from contaminated soils in a specific condition as a function of time. Monitoring ...the quality of these test results inter or within laboratory is crucial, especially if used for Environment-related legal policy or for routine testing purposes. We tested three different sandy loam type soils (Soils I, II and III) to determine the reproducibility (variability inter laboratory) of test results and to evaluate the difference in the test results within laboratory. Up-flow column percolation tests were performed following the procedure described in the ISO/TS 21268-3. This procedure consists of percolating solution (calcium chloride 1 mM) from bottom to top at a flow rate of 12 mL/h through softly compacted soil contained in a column of 5 cm diameter and 30 ± 5 cm height. Eluate samples were collected at liquid-to-solid ratio of 0.1, 0.2, 0.5, 1, 2, 5 and 10 L/kg and analyzed for quantification of the target elements (Cu, As, Se, Cl, Ca, F, Mg, DOC and B in this research). For Soil I, 17 institutions in Japan joined this validation test. The up-flow column experiments were conducted in duplicate, after 48 h of equilibration time and at a flow rate of 12 mL/h. Column percolation test results from Soils II and III were used to evaluate the difference in test results from the experiments conducted in duplicate in a single laboratory, after 16 h of equilibration time and at a flow rate of 36 mL/h. Overall results showed good reproducibility (expressed in terms of the coefficient of variation, CV, calculated by dividing the standard deviation by the mean), as the CV was lower than 30% in more than 90% of the test results associated with Soil I. Moreover, low variability (expressed in terms of difference between the two test results divided by the mean) was observed in the test results related to Soils II and III, with a variability lower than 30% in more than 88% of the cases for Soil II and in more than 96% of the cases for Soil III. We also discussed the possible factors that affect the reproducibility and variability in the test results from the up-flow column percolation tests. The low variability inter and within laboratory obtained in this research indicates that the ISO/TS 21268-3 can be successfully upgraded to a fully validated ISO standard.
Applicability of conventional leaching tests is an important issue for characterizing the leaching behavior of coarse-grained soil, since sample preparation including particle size control may affect ...the testing results. This study investigated the effects of maximum particle size of a sand gravel soil on the leaching behavior of arsenic as well as major cations. Overall, leaching concentrations of these inorganic constituents were higher in the sample containing more fine particles. However, the grading effect on the void ratio of the specimens is influential to the cumulative release since the void ratio affects both the equilibrium concentrations before percolation, as well as the flow velocity during percolation, which was observed in potassium ion release.
In order to standardize an upward style column examination, which is one of evaluation methods on leaching behavior of heavy metal from contaminated soil, nine different conditions examined in this ...study were based on an ISO/CEN standard and applied to the columns set up in three different organizations. Data on the accuracy of the column and shortening test time were collected. Results showed that maximum concentration rates, integrated elution accounts and shapes of breakthrough curve (BTC) of fluoride, arsenic, calcium, magnesium, sodium, and potassium, with higher concentrations and lower Kd, were obtained with high reproducibility under the same condition in different organization. Moreover, by packing the column with half of the sample, shape of BTC and integrated elution quantity were confirmed with high accuracy. This study also found that the samples under wet or air-dried states had little influence on the results.
Sedation in gastroenterological endoscopy has become an important medical option in routine clinical care. Here, the Japan Gastroenterological Endoscopy Society and the Japanese Society of ...Anesthesiologists together provide the revised “Guidelines for sedation in gastroenterological endoscopy” as a second edition to address on‐site clinical questions and issues raised for safe examination and treatment using sedated endoscopy. Twenty clinical questions were determined and the strength of recommendation and evidence quality (strength) were expressed according to the “MINDS Manual for Guideline Development 2017.” We were able to release up‐to‐date statements related to clinical questions and current issues relevant to sedation in gastroenterological endoscopy (henceforth, “endoscopy”). There are few reports from Japan in this field (e.g., meta‐analyses), and many aspects have been based only on a specialist consensus. In the current scenario, benzodiazepine drugs primarily used for sedation during gastroenterological endoscopy are not approved by national health insurance in Japan, and investigations regarding expense‐related disadvantages have not been conducted. Furthermore, including the perspective of beneficiaries (i.e., patients and citizens) during the creation of clinical guidelines should be considered. These guidelines are standardized based on up‐to‐date evidence quality (strength) and supports on‐site clinical decision‐making by patients and medical staff. Therefore, these guidelines need to be flexible with regard to the wishes, age, complications, and social conditions of the patient, as well as the conditions of the facility and discretion of the physician.
The programmed death-1 ligand/programmed death-1 (PD-L/PD-1) pathway has been recently suggested to play a pivotal role in the immune evasion of tumors from host immune system. In this study, we ...tried to reveal the clinical importance and therapeutic potential of the PD-L/PD-1 pathway in pancreatic cancer, which is one of the most aggressive and intractable malignant tumors.
We used immunohistochemistry to investigate PD-L expression in 51 patients with pancreatic cancer who underwent surgery and explored the therapeutic efficacy of blocking the PD-L1/PD-1 pathway in murine pancreatic cancer in vivo.
PD-L1-positive patients had a significantly poorer prognosis than the PD-L1-negative patients, whereas there was no significant correlation of tumor PD-L2 expression with patient survival. PD-L1 expression was inversely correlated with tumor-infiltrating T lymphocytes, particularly CD8(+) T cells. These clinical data have suggested that the PD-L1/PD-1 pathway may be a critical regulator in human pancreatic cancer. Monoclonal antibodies against PD-L1 or PD-1 induced a substantial antitumor effect on murine pancreatic cancer in vivo. PD-L1 blockade promoted CD8(+) T-cell infiltration into the tumor and induced local immune activation. Furthermore, the combination of anti-PD-L1 monoclonal antibody and gemcitabine exhibited a significant synergistic effect on murine pancreatic cancer and resulted in complete response without overt toxicity.
Our data suggest for the first time that PD-L1 status may be a new predictor of prognosis for patients with pancreatic cancer and provide the rationale for developing a novel therapy of targeting the PD-L/PD-1 pathway against this fatal disease.
NO2 sensing properties of yttria-stabilized zirconia (YSZ)-based gas sensors attached with various kinds of single-layered or NiO-based hetero-layered sensing electrodes (SE) have been examined in ...the operating temperature range of 500∼800°C. Although a sensor with a small-area Pt SE showed negligible NO2 response at 600°C, the lamination with a large-area NiO layer on the small-area Pt SE improved the NO2 response. In addition, the lamination with the large-area NiO layer on small-area Pt-NiO, Au or ZnO SE showed rather large NO2 response. Among all sensors tested, the sensor with the small-area Au SE laminated with the large-area NiO layer showed the largest NO2 response (ca. 49.1mV to 80ppm NO2 at 600°C). The electrochemical impedance properties of the sensor with the small-area Au SE showed larger charge transfer resistance (namely, lower electrocatalytic activity) for oxygen redox reaction than that of the sensor with the small-area Pt SE. In addition, the total of charge transfer resistance of the sensor with the small-area Au SE laminated with the large-area NiO layer decreased upon exposure to NO2 due to the simultaneous occurrence of NO2 reduction reaction. These results indicate that the large NO2 response of the sensor with the small-area Au SE laminated with the large-area NiO layer is caused by the high electrochemical activity of NO2 reduction reaction at the interface of NiO/YSZ and the low electrochemical activity for the oxygen redox reaction at Au/YSZ/gas triple phase boundaries.
It is a significant challenge for a titanium implant, which is a bio-inert material, to recruit osteogenic factors, such as osteoblasts, proteins and blood effectively when these are contained in a ...biomaterial. The objective of this study was to examine the effect of ultraviolet (UV)-treatment of titanium on surface wettability and the recruitment of osteogenic factors when they are contained in an atelocollagen sponge. UV treatment of a dental implant made of commercially pure titanium was performed with UV-light for 12 min immediately prior to the experiments. Superhydrophilicity on dental implant surfaces was generated with UV-treatment. The collagen sponge containing blood, osteoblasts, or albumin was directly placed on the dental implant. Untreated implants absorbed only a little blood from the collagen sponge, while the UV-treated implants absorbed blood rapidly and allowed it to spread widely, almost over the entire implant surface. Blood coverage was 3.5 times greater for the UV-treated implants (p < 0.001). Only 6% of the osteoblasts transferred from the collagen sponge to the untreated implants, whereas 16% of the osteoblasts transferred to the UV-treated implants (p < 0.001). In addition, a weight ratio between transferred albumin on the implant and measured albumin adsorbed on the implant was 17.3% in untreated implants and 38.5% in UV-treated implants (p < 0.05). These results indicated that UV treatment converts a titanium surface into a superhydrophilic and bio-active material, which could recruite osteogenic factors even when they were contained in a collagen sponge. The transfer and subsequent diffusion and adsorption efficacy of UV-treated titanium surfaces could be useful for bone formation when titanium surfaces and osteogenic factors are intervened with a biomaterial.
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