Effects of mangrove deforestation on fish assemblage at Pak Phanang Bay,southern Thailand

Daytime sampling using a seine net was conducted at Pak Phanang Bay (Nakhon Si Thammarat Province, Thailand) in February and July 2006, to determine differences in fish assemblage structures between a mangrove site and an adjacent site completely cleared of mangroves. The overall numbers of fish species and individuals were significantly higher at the mangrove site than the cleared site in both months. Although benthic crustacean feeders showed more species and individual numbers at the mangrove site in both months, the opposite was found for zooplankton feeders. A cluster analysis, based on the abundance of each species, demonstrated that the fish assemblage structures were distinctly different between the two sites. In addition, significant differences in length frequency distributions for each of the four most abundant species were found between the sites in February and/or July. Small individuals of Scatophagus argus, Ambassis nalua, and Tetraodon nigroviridis were more common at the mangrove site, and of Chelon subviridis at the cleared site. These results suggest that mangrove deforestation exerts marked effects on fish assemblages.     

Nondestructive detection of cracks near the surface of wooden boards by dynamic heat dissipation

A method to detect cracks near the surface of wooden boards has been developed where the change in surface temperature of the wood sample is monitored using an infrared camera following momentary heating by a flash. Cylindrical holes simulating cracks were drilled into the wood samples, and blackbody paint was painted onto the surface of the samples to assist flash absorption. This method uses the dynamic heat transport process from the blackbody paint to the surface of the wood sample to the cracks over a short timescale. The theoretical foundations of the observation method were outlined, and the technique was verified in experiments with samples of Cercidiphyllum japonicum, Western red cedar, Japanese cedar, Balsa, and medium-density fiberboard. The developed technique is able to detect the presence of holes located near the surface of some samples. However, this method could not detect the presence of holes in Balsa nor holes located deeper than 1 mm from the surface of the sample. A theoretical analysis of these phenomena was provided to help interpreting them.     

Phyllochron Dynamics Under Controlled Environments in Rice (Oryza Sativa L.)

Previously, we reported that phyllochron of rice greatly fluctuated in the course of development under natural conditions. The present study was carried out to examine the phyllochron dynamics using the five near-isogenic lines (NILs) for heading time and the recurrent parent. The change of phyllochron was investigated under four different controlled conditions regarding daylength and temperature. Growth duration (days to heading) showed a large variation among different growth regimes as well as genotypes. Changes of phyllochron were evaluated in the genotypes by using a quartic polynomial regression that was well fitted to the change of phyllochron in the present controlled environments as previously observed under natural conditions. Phyllochron began to drastically increase after around the 5th phytomer order and decreased with the progress of reproductive development in similar manners under different environments. The pattern of phyllochron change varied from a flat to non-flat shape. The shape of the equation was affected by genotypes as well as daylengths and temperatures. In addition, the shape was closely related to the growth duration (days to heading) of the genotype, suggesting that the phyllochron might internally increase depending on the genotype controlling the heading date. Therefore, the present results showed that the sufficient examination of phyllochron dynamics is necessary for understanding a variation in the heading date of rice.     

Developmental changes of phyllochron in near-isogenic lines of rice (Oryza sativa L.) with different growth durations

The repeated elements called phytomers, which consist of leaf, node, internode and axillary bud, play an important role in the development of modular organization in plants. Rice has the striking feature that the rate of the phytomer production is closely synchronized with the rate of leaf emergence (phyllochron). We examined developmental changes of phyllochron by using 10 near-isogenic lines (NILs) showing diversified growth durations in rice. The NILs were established by backcrosses with a strain practically insensitive to photoperiod, and they consisted of early- or late-flowering NILs whose differences of growth duration were caused by the combinations of alleles at 6 loci. The developmental patterns of phyllochron were evaluated by means of a quartic polynomial, which fitted well in most cases. The results indicated that phyllochron greatly changed during development, especially in late-flowering NILs as well as the recurrent parents, although the fluctuation of phyllochron was not so marked in the early-flowering NILs. Thus, the developmental change of phyllochron was highly dependent upon the genotypes and/or growth duration; however, it was associated with neither floral initiation nor temperature, indicating that the change of phyllochron might reflect internal or physiological changes which occur during the life cycle of rice. This revised version was published online in July 2006 with corrections to the Cover Date.     

Radiocesium transfer from Andosols to brown rice in the northern and northwest areas of Tochigi Prefecture,in the first 3 years following the 2011 Fukushima Daiichi nuclear power plant accident

ABSTRACT

Following the Fukushima Daiichi Nuclear Power Plant accident of 2011, the potential for radiocesium transfer from contaminated soils, such as Andosols, to agricultural crops became a significant concern. Andosols account for up to 70％ of paddy soils in the northern and northwest areas of Tochigi Prefecture, where the radiocesium concentration is 1000 Bq kg^?1 or greater in the soil of some fields. The present study was carried out in order to determine the phytoavailability of radiocesium in Andosols by comparing it with that of gray lowland soils in the first 3 years following the accident. The transfer factor (TF) tended to be higher in Andosols than in gray lowland soils, leading to higher radiocesium concentrations in brown rice grown in Andosols. The exchangeable potassium (Ex-K₂O) in Andosols was highly and negatively correlated with TF, followed by clay. The Ex-K₂O value was positively correlated with the clay/total carbon (T-C) value, suggesting that a high T–C ratio could weaken K₂O adsorption on clay mineral sites; hence, the low clay/T-C values can partially explain the relatively large TF values of Andosols. Samples with Ex-K₂O contents less than 200 mg kg^?1 and with low clay/T-C values showed striking decreases in TF values from 2011 to 2012. However, the decrease from 2012 to 2013 was quite small; radiocesium in these samples was potentially available for rice uptake for a long time, likely due to the reversible adsorption and fixation characteristics of allophane. Most gray lowland soil samples showed very low TF values over the 3 years of the study, except for those with TF values greater than 0.1 due to low Ex-K₂O and clay contents; the geometric mean (GM) value of TF was below 0.01 in 2012. The extraction of exchangeable radiocesium (Ex-Cs) with a 1 mol L^?1 ammonium acetate solution may not be an appropriate method for explaining the variability in radiocesium TF in Andosols. This is because the Ex-Cs value was significantly correlated with Ex-K₂O in Andosols, but not in gray lowland soils, indicating that Ex-K₂O explained this variability in relation to Ex-Cs.     

Autocrine or paracrine inflammatory actions of corticotropin-releasing hormone in vivo

Corticotropin-releasing hormone (CRH) functions as a regulator of the hypothalamic-pituitary-adrenal axis and coordinator of the stress response. CRH receptors exist in peripheral sites of the immune system, and CRH promotes several immune functions in vitro. The effect of systemic immunoneutralization of CRH was tested in an experimental model of chemically induced aseptic inflammation in rats. Intraperitoneal administration of rabbit antiserum to CRH caused suppression of both inflammatory exudate volume and cell concentration by approximately 50 to 60 percent. CRH was detected in the inflamed area but not in the systemic circulation. Immunoreactive CRH is therefore produced in peripheral inflammatory sites where, in contrast to its systemic indirect immunosuppressive effects, it acts as an autocrine or paracrine inflammatory cytokine.     

Polymerization-induced epitaxy: scanning tunneling microscopy of a hydrogen-bonded sheet of polyamide on graphite

A molecularly thin film of a two-dimensional polymer network formed by hydrogen bonding was synthesized and investigated with scanning tunneling microscopy. Poly(in-caprolactam) (nylon 6) was epitaxially grown on the basal plane of graphite and an ultrathin film of the polymer was obtained after the bulk materials had been washed away with solvents. The polymer chain has a planar, all-trans conformation and adjacent chains run in the antiparallel direction. This produces complete pairing of hydrogen bonding groups, with each amide group lying on a straight line perpendicular to the polymer backbone. This hydrogen-bonded sheet is oriented so that each polymer backbone lies in the (1010) direction on the graphite hexagonal lattice, as opposed to the (1120) direction taken by other paraffinic molecules studied so far. This experiment shows that hydrogen bonding can be used to control the orientation of macromolecules in two dimensions.