Micro-milling super-fine powdered activated carbon decreases adsorption capacity by introducing oxygen/hydrogen-containing functional groups on carbon surface from water

Superfine powdered activated carbon (SPAC) of micron to submicron particle size is produced by micro-milling of conventionally sized powdered activated carbon. SPAC has attracted attention because of its high adsorption capacity; however, milling to the submicron particle size range lowers its adsorption capacity. Here, we found that this decrease of adsorption capacity was due to the introduction of oxygen/hydrogen containing functional groups into the graphene structure of the carbon from water during the milling, causing it to become less hydrophobic. This finding was supported by three analyses of SPAC particles before and after milling: 1) elemental analysis revealed increased oxygen and hydrogen content, 2) Boehm titration analysis revealed increased amounts of acidic functional groups, including carboxylic and phenolic hydroxyl groups, and 3) Fourier-transform infrared spectroscopy showed increased peaks at 1200, 1580, and 3400 cm−1, confirming the presence of those groups. Dissolved oxygen concentration did not strongly affect the increase of oxygen content in SPAC, and no evidence was found for hydroxyl radical production during micro-milling, suggesting that a mechanochemical reaction underlies the increase in oxygen/hydrogen-containing functional groups. An increase in 18O content in the SPAC particles after milling in water-18O indicated that the oxygen in the functional groups originated from the surrounding water

Zn protoporphyrin IX is formed not from heme but from protoporphyrin IX

We examined the effects of exogenous myoglobin, a bivalent chelator, and nitrite on Zn protoporphyrin IX (ZPP) formation by using model systems. ZPP was formed in a model solution without addition of exogenous myoglobin. After incubation, the amount of ZPP in a model solution was increased but that of heme was not decreased compared with the amounts before incubation. Protoporphyrin IX (PPIX) instead of ZPP also accumulated in a model solution with addition of EDTA, but the amount of heme was not reduced. These results suggested that ZPP was not formed by the Fe-Zn substitution in heme but was formed by the insertion of Zn into PPIX, which was formed independently. The fact that the effects of various factors in model systems with/without addition of a bivalent chelator were similar suggested that ZPP formation was strongly affected by PPIX formation. Inhibition of PPIX formation by nitrite might be the reason for the low levels of ZPP in cured meats

Effects of decreasing activated carbon particle diameter from 30 mu m to 140 nm on equilibrium adsorption capacity

The capacity of activated carbon particles with median diameters (D50s) of >similar to 1 mu m for adsorption of hydrophobic micropollutants such as 2-methylisolborneol (MIB) increases with decreasing particle size because the pollutants are adsorbed mostly on the exterior (shell) of the particles owing to the limited diffusion penetration depth. However, particles with D50s of <1 mu m have not been thoroughly investigated. Here, we prepared particles with D50s of similar to 30 mu m-similar to 140 nm and evaluated their adsorption capacities for MIB and several other environmentally relevant adsorbates. The adsorption capacities for low-molecular-weight adsorbates, including MIB, deceased with decreasing particle size for D50s of less than a few micrometers, whereas adsorption capacities increased with decreasing particle size for larger particles. The oxygen content of the particles increased substantially with decreasing particle size for D50s of less than a few micrometers, and oxygen content was negatively correlated with adsorption capacity. The decrease in adsorption capacity with decreasing particle size for the smaller particles was due to particle oxidation during the micromilling procedure used to decrease D50 to similar to 140 nm. When oxidation was partially inhibited, the MIB adsorption capacity decrease was attenuated. For high molecular-weight adsorbates, adsorption capacity increased with decreasing particle size over the entire range of tested particle sizes, even though particle oxygen content increased with decreasing particle size

Mechanism of sampling disturbance for peat ground and its influence on mechanical properties

A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube

Analysis of long-term settlement of road embankment on peat ground during its service period

Roads on peat grounds are subject to stringent requirements in terms of controlling the residual settlement during their service period in order to minimize the post-construction maintenance work. This paper addresses the applicability of the Finite Element Method (FEM) by incorporating a time-dependent model for peats to an evaluation of the residual settlement. The applicability of isotach viscoplasticity, used to describe the peats’ behavior under variable-rate compression, was confirmed in laboratory tests. Long-term consolidation test results and a model simulation revealed the particular importance of two mechanisms in the residual settlement in peat grounds, namely, the stress-dependency of the coefficient of consolidation, cv, and the viscosity-induced secondary consolidation. A model peat ground, capturing these mechanisms, was implemented for the FEM and applied to a case history of a high-standard road construction in Hokkaido, Japan. The viscoplastic parameters determined from standard oedometer tests successfully reproduced the observed long-term settlement in a peat-dominated section of the expressway. The analysis was extended to address the settlement in the peat ground with the installation of prefabricated vertical drains (PVDs). The results indicate that the delayed primary consolidation due to the stress-induced cv reduction can be significantly alleviated, while the settlement arising from the secondary consolidation over a longer term is little affected by the PVDs. These insights point to the importance of untangling the two mechanisms of long-term settlement for the sake of making accurate predictions of the residual settlement in different time scales

A rational design approach to peat ground improvement by vertical drains

Use of the vertical drain method (hereinafter called "VD") in peat ground is spreading to reduce residual settlement and increase strength by accelerating consolidation. In recent years, high embankments of nearly 10 m have been constructed on peat ground by using a combination of VDs, or plastic-board drains (PBDs) in particular, and various ground stabilization techniques. However, the conventional design methods include a number of unclear points. This paper focuses on the significant stress-dependency of coefficient of consolidation in peat, and describes a rational design approach to evaluating the long-term settlement and stability of foundation ground of VD-improved peat ground by modifying conventional design methods. The effect of VDs was evaluated from field observations on the settlement of test embankments constructed in Hokkaido, Japan, and simulations using the finite-element method were performed to interpret the behavior of the ground. A systematic series of parametric analyses demonstrated that, in peat ground with a high natural water content, the permeability decreases drastically as the load increases, and hence the residual settlement increases significantly and the stability is greatly reduced. Therefore, drain pitch needs to be considerably small under such conditions. Despite its common use in the conventional design of vertical drains, the accuracy of Barron's solution is naturally limited in peat ground with high natural water contents since it assumes a constant value for the coefficient of consolidation

Rasagiline monotherapy in early Parkinson's disease: A phase 3, randomized study in Japan

Background: Rasagiline is a monoamine oxidase type-B inhibitor in development in Japan for Parkinson's disease (PD). The objective of this Phase 3, randomized, double-blind study was to evaluate the efficacy and safety of rasagiline in Japanese patients with early PD (NCT02337725). Methods: Patients were 30–79 years old with a diagnosis of PD within 5 years. Following a two-week placebo run-in period, patients were randomized 1:1 to receive rasagiline (1 mg/day) or placebo for up to 26 weeks. The primary endpoint was change from baseline in the MDS-UPDRS Part II + III total score (TS). Secondary endpoints included the MDS-UPDRS Parts II + III, III, II, and I TS and safety. Results: In total, 118 patients were randomized to rasagiline and 126 to placebo. Patient characteristics at baseline were similar in both groups. The change from baseline in the MDS-UPDRS Part II + III TS was significantly greater in the rasagiline vs. placebo group (rasagiline-placebo: −6.39, 95% CI: −8.530, −4.250; P < 0.0001). The mean changes from baseline in the MDS-UPDRS Part II + III, Part III and Part II TS were lower at treatment visits between weeks 6 and 26 in the rasagiline vs. placebo groups. The overall incidence of treatment-emergent adverse events (TEAEs) was 62.4% and 52.4% in the rasagiline and placebo groups, respectively; most frequent TEAE was nasopharyngitis (15.4% and 15.1%). Conclusion: Treatment with oral rasagiline 1 mg/day was effective and well-tolerated in Japanese patients with early PD, with a significantly greater improvement in the MDS-UPDRS Part II + III TS vs. placebo, and a similar safety profile

Experience and Daily Burden of Patients with Chronic Kidney Disease Not Receiving Maintenance Dialysis or Renal Transplantation

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