Early hospital readmission was less likely for hemodialysis patients from facilities with longer median length of stay in the DOPPS study

The length of hospital stay is considered to influence hospital readmission in general. The Dialysis Outcomes and Practice Patterns Study (DOPPS), an international prospective observational study undertaken to establish a relationship between facility practices and dialysis outcomes, started in 1996. Results suggest that the duration of hospital stay is significantly correlated with the probability of early readmission in dialysis patients. Thus, early hospital readmission was observed to be less likely for hemodialysis patients from facilities with longer median length of stay. The lengths of hospital stay for hemodialysis patients differed in the three continents studied. Although socioeconomic pressures may drive the lengths of hospital stay, the duration of hospitalization should be determined keeping in mind the safety of clinical course for each disease. In this forum, a 47-year-old female hemodialysis patient with severe secondary hyperparathyroidism, who had been treated with hemodialysis for 21 years, was hospitalized with severe clinical symptoms. Although the clinical symptoms disappeared 10 days after total parathyroidectomy with autotransplantation, severe hypocalcemia persisted despite large amounts of intravenous calcium gluconate. This patient was hospitalized for a long duration owing to the large calcium deficit in her body. Had the length of her hospital stay been shortened, either she could have needed rehospitalization or her condition could have worsened.     

Characterization of denitrifying polyphosphate-accumulating organisms in activated sludge based on nitrite reductase gene

Nitrite reductase gene (nirS) fragments in the activated sludge obtained from a sequencing batch reactor (SBR) under anaerobic-aerobic condition were cloned and classified by restriction fragment length polymorphism (RFLP) analysis, and representative fragments were sequenced. One of the nirS clones was approximately 70% of all nirS clones in anaerobic/aerobic (existing oxygen and nitrate) cycle operation in which a large amount of anoxic phosphate uptake was observed. Although the activated sludge samples analyzed might contain bacteria that did not accumulate polyphosphate, it was likely that this nirS fragment sequence was that from denitrifying polyphosphate-accumulating organisms (DNPAOs) which can utilize both oxygen and nitrate as electron acceptors. The sequence was similar to the nirS sequences of Thauera mechernichensis (83% similarity) and Azoarcus tolulyticus (83% similarity) both of which belong to the Rhodocyclus group.     

Fabrication of subwavelength structure for improvement in light-extraction efficiency of light-emitting devices using a self-assembled pattern of block copolymer

A new fabrication method to improve the optical extraction efficiency of light-emitting devices is presented. The morphology of a self-assembled block copolymer was transferred to the surface of a compound semiconductor to achieve a subwavelength columnar structure. The optical extraction efficiency of the substrates with subwavelength columnar structures of 350 nm pillar height, 130 nm diameter, and 180 nm pitch, improved 2.2 times compared to unprocessed substrates. This method does not require expensive exposure lithography tools and is therefore suitable for conventional semiconductor processes.     

Effect of fatty oil dispersion on oil-containing wastewater treatment

The performance of an immobilized continuous fluidized reactor for salad oil-containing model wastewater was examined at a high loading rate using polyurethane as a support, to be applied in fat- and oil-containing wastewater treatment, generated by daily activities in restaurant kitchens. At an organic loading rate higher than 0.6 kg/m3/day, there was a significant amount of white solid (WS), identified as a mixture of calcium di-stearate and di-palmitate, suggesting that saturated fatty acid degradation was limited at such a high loading rate, possibly due to its solubility in the wastewater. Increased oil dispersion by the addition of a surfactant ranging from 10 to 100 microm particle size could result in less than 30 mg/l oil concentration after the treatment at 5 kg/m3/day.     

Effect of salinity on nitrous oxide emission in the biological nitrogen removal process for industrial wastewater

The effects of wastewater salinity on both nitrogen removal efficiency and N2O emission rate were investigated in a single nitrification process, a single denitrification process and an anoxic-oxic activated sludge process. In the single nitrification process, by increasing the salt concentration from 1.0 to 2.0 wt%, the N2O conversion ratio in the steady state increased by 2.2 times, from 0.22 to 0.48%. In the single denitrification process, a minimal change in the N2O conversion ratio was observed in the steady state even when the salt concentration was increased from 3.0 to 5.0 wt%. From the results of the anoxic-oxic activated sludge process, it was found that a salt concentration increase from 1.6 to 3.0 wt% significantly increases the N2O conversion ratio from 0.7 to 13%. It is suggested that an increase in salt concentration markedly influences N2O emission both directly and indirectly via the inhibition of N2O reductase activity. The indirect inhibition is due to the high concentration of dissolved oxygen which is transported from the oxic tank to the anoxic tank through the circulated liquid. Thus, the salt concentration should be maintained below 3.0% to suppress N2O emission in an anoxic-oxic activated sludge process.     

Does pyrite oxidation contribute to the acidification of tropical peat? A case studyin a peat swamp forestin Central Kalimantan,Indonesia

The chemical properties of peat pore water in the basin of the Sebangau River and Lahei district, Central Kalimantan, Indonesia, were studied. We analyzed major ions, pH, electrical conductivity (EC) and redox potential (Eh) of the peat pore water with reference to their vertical profile. We evaluated the contribution of sulfates to the acidi.cation of peat by including data from Furen mire, eastern Hokkaido, Japan. The coastal peat of Furen mire and the peat in Paduran in the lower basin of the Sebangau River included extraordinarily high concentrations of sulfates (> 1000 mg/l) compared to the peat in the middle and upper basins of the river (< 10 mg/l). High concentrations of sulfates, however, did not lead to a low pH for the peat. The present findings suggest that the acidification of the peat pore water is subject to the production of organic acids originating from peat decomposition, rather than the production of sulfuric acid produced by pyrite oxidation in the underlying mineral sediments.     

Self-Organized Superfluid States in Gravity and Heat Flow

When ⁴ He is heated from above near the superfluid transition, there can appear a self-organized region, either in normal fluid or superfluid, with the temperature gradient equal to the transition temperature gradient. When it is in a superfluid state, there can be two regimes. Regime M is realized relatively far from the superfluid transition, where thermal resistance due to vortices is described in terms of the conventional Gorter–Mellink mutual friction. In regime G vortices are densely generated, where the line density in units of ^–2 is much larger than in any other previous experiments. Such a self-organized superfluid can coexist with a normal fluid or a superfluid containing only a small number of vortices in a dynamical steady state.     

Effect of pretreatment conditions on the determination of major and trace elements in coal fly ash using ICP-AES

Microwave-assisted acid digestion (MW-AD) followed by atomic spectrometries such as inductively coupled plasma-atomic emission spectrometry (ICP-AES) was examined for the determination of major and trace elements in coal fly ash (CFA). Effective digestion conditions were studied using four certified reference materials of CFA, with particular focus on the composition of acid mixture and the removal of HF after MW-AD. When MW-AD was conducted without using HF (HNO₃+H₂O₂), the tested elements yielded fairly poor recoveries. When MW-AD with HF (HNO₃+HF+H₂O₂) was carried out, two methods for HF removal were attempted, H₃BO₃ addition and evaporation of acids. In the former method, while the recoveries of major elements (Al, Ca, Fe, and Mg) were satisfactory, those of trace elements were not satisfactory; in particular, the recovery of Pb was fairly low. In the latter method, the recoveries of Al, Ca, and Mg were extremely poor; however, those of other elements including the trace elements (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) were satisfactory. In this paper, the optimization of the digestion method for ICP-AES is discussed. Further, the advantages and limitations of ICP-AES in the determination of elements in CFA are assessed.     

Morphological changes of carbides during creep and their effects on the creep properties of inconel 617 at 1000 °C

Creep tests have been correlated with microstructural changes which occurred during creep of Inconel 617 at 1000 °C, 24.5 MPa. The following results were obtained: 1) Fine intragranular carbides which are precipitated during creep are effective in lowering the creep rate during the early stages of the creep regime (within 300 h). 2) Grain boundary carbides migrate from grain boundaries that are under compressive stress to grain boundaries that are under tensile stress. This is explained in terms of 1 the dissolution of relatively unstable carbides on the compressive boundaries, 2 the diffusion of the solute atoms to the tensile boundaries and 3 the reprecipitation of the carbides at the tensile boundaries. The rate of grain boundary carbide migration depends on grain size. 3) M₂₃C₆ type carbides, having high chromium content, and M₆C type carbides, having high molybdenum content, co-exist on the grain boundaries. M₂₃C₆ type carbides, however, are quantitatively predominant. Furthermore, M₆C occurs less frequently on the tensile boundaries than on the stress free grain boundaries. This is attributed to the difference of the diffusion coefficients of chromium and molybdenum. 4) The grain boundaries on which the carbides have dissolved start to migrate in the steady state creep region. The creep rate gradually increases with the occurrence of grain boundary migration. 5) The steady state creep rate depends not so much on the morphological changes of carbides as on the grain size of the matrix.