Immunomodulatory and cytotoxic effects of various Lactococcus strains on the murine macrophage cell line J774.1

In a series of in vitro culture experiments using the murine macrophage-like cell line, J774.1, we investigated the ability of 46 different Lactococcus lactis strains to induce production of the cytokines interleukin (IL)-6, IL-12 and tumor necrosis factor (TNF)-alpha. The extent of induction of IL-6, IL-12 and TNF-alpha was strain-specific and was not related to subspecies, biovariety, or the source of the isolate. When incubated with a high concentration of viable cells of some lactococcal strains, J774.1 cells hardly produced cytokines in which case the percentage of J774.1 cells that were double-stained with the apoptosis probe FITC-labeled annexin V and propidium iodide was significantly increased. This finding suggests that perturbation of cytokine induction is due to the cytotoxic effects of these strains. On the other hand, when incubated with living cells of other strains, even at a high concentration, J774.1 cells produced IL-6, IL-12 and TNF-alpha. In these cases, FITC-labeled annexin V interacted with these cells, suggesting that incubation with these strains causes phosphatidylserine to be exposed at the cell surface. The ability of these strains to induce TNF-alpha, but not IL-6 and IL-12, was lost after heat treatment, suggesting that the stimulus required for TNF-alpha induction is heat sensitive and is different from those required for IL-6 and IL-12 induction. The specificity of cytokine induction by different lactococci is discussed in terms of interaction of non-pathogenic bacteria with macrophages, as well as the implications for the use of lactococci as probiotics.     

X-ray photoemission spectroscopy analysis of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells

We report on the electronic structure of three different types of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells observed by hard X-ray photoemission spectroscopy. Prepared samples are derived from: (1) melamine and poly(furfuryl alcohol), (2) nitrogen-doped carbon black and (3) cobalt phthalocyanine and phenolic resin. C 1s spectra show the importance of sp² carbon network formation for the oxygen reduction reaction (ORR) activity. N 1s spectra of the carbon-based cathode catalysts are decomposed into four components identified as pyridine-like, pyrrole- or cyanide-like, graphite-like, and oxide nitrogen. Samples having high oxygen reduction reaction activity in terms of oxygen reduction potential contain high concentration of graphite-like nitrogen. O 1s spectra are similar among carbon-based cathode catalysts of different oxygen reduction reaction activity. There is no correlation between the ORR activity and oxygen content. Based on a quantitative analysis of our results, the oxygen reduction reaction activity of the carbon-based cathode catalysts will be improved by increasing concentration of graphite-like nitrogen in a developed sp² carbon network.     

Effect of flashing light from blue light emitting diodes on cell growth and astaxanthin production of Haematococcus pluvialis

To conserve energy in the production of astaxanthin by the green alga Haematococcus pluvialis, we utilized intermittent flashing light from blue light emitting diodes (LEDs) and investigated the effects of the incident light intensity (2-12 micromol m(-2) s(-1)), duty cycle (17-67%) and frequency (25-200 Hz) of flashing on the cell growth and astaxanthin production. In the above ranges, the final astaxanthin concentration under illumination by flashing light was significantly higher than that obtained under illumination with continuous light at the same incident intensity. For example, flashing light at an incident intensity of 8 micromol m(-2) s(-1) gave the same final astaxanthin concentration that was obtained under continuous light illumination at 12 micromol m(-2) s(-1), thus reducing energy consumption by 1/3. We therefore conclude that flashing light from blue LEDs is a promising illumination method for indoor algal cultivation using photobioreactors.     

In situ ERDA measurements of hydrogen isotope concentrations in palladium at atmospheric pressure

In situ elastic recoil detection analysis (ERDA) measurements in gases at atmospheric pressure have been carried out using 15 MeV ⁴He ion beams. The beams are extracted through a molybdenum foil having a thickness of 5 μm. The maximum depth of analysis is about 4 μm for the palladium hydride and palladium deuteride (PdH_x and PdD_x, x = 0.7-0.8) samples. The temperature of the samples rises stepwise from room temperature to 180 °C. ERDA spectra are obtained every 2 min. Hydrogen and deuterium in the samples are discharged in the temperature range of 120-140 °C in a vacuum. Decrease in the hydrogen concentration in the PdH_x sample heated in a vacuum follows a first order in the value of x and an apparent activation energy of discharge of hydrogen is 1.05 eV. On the other hand, the hydrogen and deuterium concentrations decrease at about 80 °C in air. No isotope effects are observed in both a vacuum and air. The temperature at which the hydrogen concentration decreases in helium gas is almost the same as that in a vacuum. It indicates that hydrogen and deuterium atoms are discharged by chemical reactions with air and that there are no effects of cooling of the thermocouple by convection of air.     

Fundamental studies on chlorine behavior as related to zinc electrowinning from aqueous chloride electrolytes

Measurements were made on the transport and equilibrium properties of dissolved chlorine in aqueous HC1, HCl-ZnCl₂, HCl-MgCl₂, and water. These measurements included solubility, absorption rates during bubbling, stripping rates during nitrogen bubbling, and cathodic reduction rates. The solubility of chlorine was found to be affected by speciation into aqueous Cl₂, HC1O, and C1₃ −. With increasing HCl concentration, the solubility of chlorine decreased to a minimum at 0.2 mol dm⁻³, followed by a slow and linear increase. Metal chloride salts depressed the chlorine solubility approximately in proportion to concentration. Mass transfer of aqueous chlorine was found to support a current of about 100 A m⁻² from a chlorine-saturated ZnCl₂-HCl solution under typical zinc electrowinning conditions. Comparisons with published zinc electrowinning papers indicate that air sparging would eliminate dissolved chlorine sufficiently to remove the need for diaphragm cell separation of dissolved chlorine, insofar as current inefficiencies due to cathodic chlorine reduction are concerned.     

Analysis of temperature noise propagation in a large fuel subassembly of FBR

We have developed a method to calculate the three-dimensional distribution of root-mean-square (RMS) values of temperature noise in the single phase flow in a fast reactor fuel subassembly with a local flow blockage. Employed are the subchannel method in a pin bundle region and the finite difference method in the region downstream of the bundle. We have compared the calculated RMS values of temperature noise with experimental data for a sodium loop test using a wire-spacered 91-pin-bundle fuel sub-assembly with a local blockage. We have investigated the possibility of detection of the blockage by temperature noise by taking into account the influence of structures in the upper part of the subassembly.     

Using a surface complexation model to predict the nature and stability of nanoparticles

Nanoparticles are discrete nanometer-scale assemblies of atoms and have dimensions between those characteristic of ions and those of macroscopic materials. These minerals commonly possess extremely large specific surface areas and surface adsorption capacities for foreign ions. Due to the large specific surface area and large fraction of surface atoms, the natures of nanoparticles are expected to be modified by the adsorption (surface complexation) process. In this paper,we discuss theoretically the stability of nanoparticles that make the surface complex with foreign ions. The principal theoretical assumption is that the surface complexation occurs at the bulk of the nanoparticles, as in a solid solution. The surface complexation affects two aspects of the intrinsic stability of the nanoparticles simultaneously: one is the composition of the nanoparticles; the other is the free energy of formation of nanoparticles. The solubility of hydrous ferric oxide (HFO) was estimated by using surface complexation modeling coupled with published data of the free energy of formation of the relevant components. The solubility modeling of surface-charged (H+ or OH- sorbed) HFO mechanistically and quantitatively explained the observed nonintegral behavior of the solubility of HFO. Moreover, solubility modeling of anion (SO4(2-), PO4(3-), and As(V)) sorption by HFO showed that the sorption process strongly influences the stability of the nanoparticles. This result implies that geochemical modeling leads to the erroneous prediction of a natural system if the effect of the sorption process is not taken into account.     

Anaerobic degradation of cis-1,2-dichloroethylene and vinyl chloride by Clostridium sp. strain DC1 isolated from landfill leachate sediment

The bacterial community structure of anaerobic enrichment cultures that are capable of degrading both cis-1,2-dichloroethylene (cis-DCE) and vinyl chloride (VC) and isolation of the organism responsible for the degradation were investigated. Denaturing gradient gel electrophoresis (DGGE) of a PCR-amplified 16S rRNA gene from the cultures showed the possible predominance of Clostridium species. One isolate, designated strain DC1, was closely related to members of Clostridiaceae, based on 16S rRNA gene analysis, and the highest sequence similarity (98.9%) was obtained for Clostridium saccarobutylicum. In culture experiments, strain DC1 was shown to degrade cis-DCE and VC during the stationary phase of growth without accumulation of VC and/or ethene. The bacterial growth was not linked to the degradation of cis-DCE and VC. Stoichiometric analysis revealed that two moles of chloride ions as released from one mole of cis-DCE during the incubation period, indicating that cis-DCE was fully dechlorinated. The results appear consistent with the presence of a mechanism of oxidative dechlorination rather than respiratory reductive dechlorination; the latter is accompanied by transient formation of dechlorinated ethenes from cis-DCE and VC.     

Composting cattle dung wastes by using a hyperthermophilic pre-treatment process: characterization by physicochemical and molecular biological analysis

To solve malodorous odor problems by ammonia emission in composting of cattle dung wastes, we developed an alternative composting method consisting of a hyperthrmophilic pre-treatment reactor (HTPRT) (first step) combined with a general windrow post-treatment system (WPOT) (second step). In this study, physicochemical and microbiological differences in compost materials during the HTPRT-WPOT process and a simple windrow composing process (SWC) were investigated. The HTPRT-WPOT process removed excess ammonia in the compost materials by physical ammonia stripping, and controlled the malodorous ammonia emission. The organic matter evolution index showed that the HTPRT-WPOT process also contributed to accelerate formation of humic acids in composting. Quantitative real-time PCR analyses using Bacterial-, Archaeal- and fungal-protozoan-specific primer sets showed that small subunit ribosomal RNA (SSU rRNA) gene copy numbers differed much between composting materials of these two processes. Particularly, the SSU rRNA gene copy of eukaryotic microbes (fungi-protozoa) in the HTPRT-WPOT process was much higher than in the SWC process. From these results, we conclude that the HTPRT-WPOT process has great advantages for the control of malodorous odor problems caused by ammonia emission, and for high rate of composting evaluated by the humification rate and microbial characterization of the composting materials.