Recovery of gold by chicken egg shell membrane-conjugated chitosan beads

We have successfully prepared a bead-type adsorbent from two materials with different adsorption characteristics. Heavy metals were removed by greatly swollen egg shell membrane-conjugated chitosan beads. The egg shell membrane accumulated and removed precious metal ions from a dilute aqueous solution with a high affinity in a short contact time. Experiments suggested that chitosan beads could take up gold ions with great capacity and selectivity by conjugation with egg shell membrane. Under certain conditions, the selective removal of gold and copper in a mixture of gold and copper ions by egg shell membrane-conjugated chitosan beads was 100% and 2%, respectively. Egg shell membrane-conjugated chitosan beads can be seen as a promising material to recover gold in wastewater from various industries, such as electroplating.     

Infectious waste management in Japan: a revised regulation and a management process in medical institutions

In Japan, the waste management practice is carried out in accordance with the Waste Disposal Law of 1970. The first rule of infectious waste management was regulated in 1992, and infectious wastes are defined as the waste materials generated in medical institutions as a result of medical care or research which contain pathogens that have the potential to transmit infectious diseases. Revised criteria for infectious waste management were promulgated by the Ministry of Environment in 2004. Infectious waste materials are divided into three categories: the form of waste; the place of waste generation; the kind of infectious diseases. A reduction of infectious waste is expected. We introduce a summary of the revised regulation of infectious waste management in this article.     

Solventless Delignification of Wood Flour with TiO2/poly(ethylene oxide) Photocatalyst System

A novel solventless delignification of a defatted Picea glehnii wood flour sample was performed using a TiO₂/polyethylene oxide (PEO) photocatalyst system. A cell wall structure of the wood flour was directly observed, showing that its lignin fraction was removed by the photodegradation. The total lignin amount was slightly decreased as compared with that of the pristine sample, and the vanillin formation was confirmed by the ¹H-NMR measurement. The TiO₂ worked as a radical initiator, and simultaneously acid and aldehyde compounds produced by the PEO photolysis did as an accelerator for the solventless delignification. Although the photocatalyst system showed high delignification activity even for a low molecular lignin model, the delignification of the wood flour sample was confined to the surface. It was found that the suppressed delignification behavior was due to crosslinked structure of lignin.     

Preparation and Characterization of Cellulose/Polypropylene Composite Using an Oxidatively Degraded Polypropylene

In this work, an oxidatively degraded polypropylene (DgPP) was studied as a novel coupling agent for fibrous cellulose (FC)/polypropylene (PP) composite. An optimal preparation time of PP thermal oxidative degradation was 18 h at 130 °C, and the DgPP had functional groups such as γ-lactone and acid groups. The spherulite observation of the DgPP suggested miscibility for the undegraded PP. The addition of the DgPP presented the transparency improvement of FC/PP composite, and this behavior was found to be originated from the grafted DgPP, which was produced by the esterification reaction between the of FC and the DgPP. The scanning electron microscope (SEM) observation showed that the grafted DgPP coated the FC surface, and the tensile strength of the FC/PP composite increased by an appropriate amount of the DgPP addition. These results suggested that the DgPP was suitable for the coupling agent of FC/PP composite.     

Silver speciation in liver of marine mammals by synchrotron X-ray absorption fine structure and X-ray fluorescence spectroscopies

The chemical form of Ag in the livers of five species of marine mammals was examined using X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies. The XAFS analysis suggested that Ag(2)Se was present in the livers of the Franciscana dolphin (Pontoporia blainvillei), Dall's porpoise (Phocoenoides dalli), and Baird's beaked whale (Berardius bairdii), whereas Ag(2)S was present in the livers of the striped dolphin (Stenella coeruleoalba) and pygmy killer whale (Feresa attenuata). XRF spectroscopy results revealed that the distribution patterns of Ag and Se in a thin section of the liver of the Franciscana dolphin were the same; this also implied that Ag was associated with Se in the liver. Thus, the interaction of Ag with Se or S may offer significant protection against the toxicity of Ag in marine mammals. The formation of either Ag(2)Se or Ag(2)S might depend on the Hg levels in the liver. Ag(2)Se was observed in liver samples with relatively high Ag/Hg ratio, whereas liver samples with low Ag/Hg ratio contained Ag(2)S.     

Properties of a Poly(3-hydroxybutyrate) Depolymerase from Penicillium funiculosum

A poly(3-hydroxybutyrate) (PHB) depolymerase was purified from a fungus, Penicillium funiculosum (IFO6345), with phenyl-Toyopearl and its properties were compared with those of other PHB depolymerases. The molecular mass of the purified enzyme was estimated at about 33 kDa by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The pH optimum and pI were 6.5 and 6.5, respectively. The purified protein showed affinity to Con A-Sepharose, indicating that it is a glycoprotein. Diisopropylfluorophosphate and dithiothreitol inhibited the depolymerase activity completely. The N-terminal amino acid sequence of the purified enzyme was TALPAFNVNPNSVSVSGLSSGGYMAAQL, which contained a lipase box sequence. This purified enzyme is one of the extracellular PHB depolymerase which belong to serine esterase. The purified enzyme showed relatively strong hydrolytic activity against 3-hydroxybutyrate oligomers compared with its PHB-degrading activity. PHB-binding experiments showed that P. funiculosum depolymerase has the weakest affinity for PHB of all the depolymerases examined.     

Predicted Genetic Consequences of Strong Fertility Selection Due to Pollinator Loss in an Isolated Population of Primula sieboldii

Previous studies demonstrated strong fertility selection for a self-fertile, homostyle morph due to pollinator loss in an isolated population of Primula sieboldii , an endangered heterostylous species. To predict genetic consequences of the selection we developed a deterministic genetic model based on a classical "supergene" model, and we studied the effects of pollinator availability and inbreeding depression on temporal changes of morph frequencies through model simulation. Because of the severe pollinator limitation experienced by the population, fast, irreversible loss of the thrum morph from the population was predicted, even if high inbreeding depression was assumed. To prevent the breakdown of the normal breeding system of the species, morph frequency monitoring for timely active management should be implemented. Active management should include hand pollinations and pollinator therapy—reintroduction and reestablishment of suitable pollinator populations. The method we adopted in this study to parametrize pollinator availability can be used widely in conservation modeling for a range of plant species that have multiple mating types with different degrees of self-incompatibility.     

Evolutionary relationships of deep-sea mussels inferred by mitochondrial DNA sequences

In order to elucidate the evolutionary process of deep-sea Bathymodiolus mussels, we investigated the phylogenetic relationships of 16 species worldwide by analyzing nucleotide sequences of the mitochondrial COI and ND4 genes. Deep-sea mussels were clustered into three groups by basal trichotomous divergence. The first was composed of four species found in Japanese waters and one species from the Gulf of Mexico, which contain methanotrophic endosymbiotic bacteria. The second included nine species distributed in the West and East Pacific, Indian, and Atlantic Oceans. Members of the second group were trichotomously divided into the Indo-West Pacific, Atlantic, and East Pacific subclusters. The Indo-West Pacific subcluster was composed of three very closely related species with mutual genetic distances at the intraspecific level (av. 0.019 in COI and 0.009 in ND4 relative to av. 0.156 in COI and 0.265 in ND4 among Bathymodiolus species other than Cluster A species), suggesting some gene flow among these species. The third consisted of two West Pacific species. Species in the second and third groups contain mainly thioautotrophic endosymbionts, including some species harboring both methanotrophs and thioautotrophs.     

Measurement of photosynthetic production of a marine phytoplankton population using a stable 13C isotope

The use of stable isotope of carbon, ¹³C, for the determination of the photosynthetic rate of a marine phytoplankton population was examined. Particular concern was paid to the effects of non-phytoplanktonic organic carbon and the enrichment of inorganic carbon on the estimation of the photosynthetic rate. Photosynthetic rates determined by the ¹³C method showed a remarkable agreement with those determined by the ¹⁴C method. Insitu determinations of photosynthetic rate were made in three different water types: open ocean, coastal and neritic waters, which included oligo- and mesotrophic waters, by using the ¹³C method established.