Oxidative cleavage of lignin aromatics during chlorine bleaching of kraft pulp

Methanol liberation and methoxyl loss during chlorine bleaching of softwood kraft pulp were quantitatively investigated to estimate the degree of structural modification of lignin aromatics. An increase in the chlorine multiple led to enhanced methoxyl loss from lignin. Our result, using pH-adjusted chlorine water (pH 5.7), by which chlorination under oxidation-favorable conditions was achieved, strongly supported the importance of the oxidation reaction by chlorine during delignification and lignin degradation. It was also suggested that methanol can be produced not only via catalytic hydrolysis by chlorine but via oxidative cleavage of the ether bond as well. The infrared spectrum of chlorolignins suggested that chlorine oxidation can open aromatic rings to muconic acid derivatives without cleaving ether bonding of the methoxyl group. No straight relation between the methoxyl content and the kappa number of chlorinated pulps was shown. The methoxyl content of bleached kraft pulps subjected to successive chlorination and alkali extraction showed a good relation with the kappa number. This means that almost all the portions of the oxidatively modified lignin structure were successfully removed during these treatments, and the aromatic structures of residual lignin in chlorinated and alkali-extracted pulps were thought to remain intact.Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Kumamoto, April 1996; the 10th International Symposium on Wood and Pulping Chemistry, Yokohama, June 1999; and the 67th Pulp and Paper Research Conference, Tokyo, June 2000     

Dependence of self-tolerance on TRAF6-directed development of thymic stroma

The microenvironments of the thymus are generated by thymic epithelial cells (TECs) and are essential for inducing immune self-tolerance or developing T cells. However, the molecular mechanisms that underlie the differentiation of TECs and thymic compartmentalization are not fully understood. Here we show that deficiency in the tumor necrosis factor receptor-associated factor (TRAF) 6 results in disorganized distribution of medullary TECs (mTECs) and the absence of mature mTECs. Engraftment of thymic stroma of TRAF6(-/-) embryos into athymic nude mice induced autoimmunity. Thus, TRAF6 directs the development of thymic stroma and represents a critical point of regulation for self-tolerance and autoimmunity.     

The effect of magmatic activity on hydrothermal venting along the superfast-spreading East pacific rise

A survey of hydrothermal activity along the superfast-spreading (approximately 150 millimeters per year) East Pacific Rise shows that hydrothermal plumes overlay approximately 60 percent of the ridge crest between 13 degrees 50' and 18 degrees 40'S, a plume abundance nearly twice that known from any other rige portion of comparable length. Plumes were most abundant where the axial cross section is inflated and an axial magma chamber is present. Plumes with high ratios of volatile ((3)He, CH(4), and H(2)S) to nonvolatile (Mn and Fe) species marked where hydrothermal circulation has been perturbed by recent magmatic activity. The high proportion of volatile-rich plumes observed implies that such episodes are more frequent here than on slower spreading ridges.     

Chenopodium quinoa strains suitable for quantitative assay of potato virus S

Summary Eight strains ofChenopodium quinoa were compared, under the controlled conditions, to determine their sensitivity in terms of local lesion production by potato virus S. ‘Valdivia’, one of the most sensitive strains to three isolates of PVS, produced numerous visible local lesions 5 days after inoculation. ‘Selection C’ also was highly susceptible to the three virus isolates, and local lesions were more distinctive than those in ‘valdivia’.

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Zusammenfassung Um die Anf?lligkeit für 3 Isolate des Kartoffelvirus S (PVS) zu bestimmen, wurden 8 Linien vonChenopodium quinoa in einer Klimakammer (27 °C bei 16 Stunden Lichtdauer; Lichtintensit?t: 5380 Lux) untersucht. Klare Unterschiede wurden gefunden im Typ der Lokall?sionen, im Grad der L?sionsdeutlichkeit, in der L?sionsgr?sse und in der Inkubationsdauer (Tabelle 1, Abb. 1). Dagegen wurden in der Reaktion der 8 Linien vonC. quinoa zwischen den drei geprüften PVS-Isolaten keine ausgepr?gten Unterschiede festgestellt. In einem detaillierten Vergleich erzeugte ‘Valdivia’, eine der empfindlichsten Linien, 5 Tage nach der Inokulation zahlreiche Lokall?sionen. Die Lokall?sionen auf ‘Selection C’ waren ausgepr?gter als jene auf ‘Valdivia’ (Abb. 2). Es kann also daraus geschlossen werden, dass ‘Valdivia’ und ‘Selection C’ als Massentestpflanzen für PVS gleich gut geeignet sind. Die Auswahl zur Benützung einer dieser Linien kann vom speziellen Zweck einer vorgesehenen Studie abh?ngen.

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Résumé Afin de déterminer leur sensibilité à 3 isolats de virus S de la pomme de terre (PVS), 8 souches deChenopodium quinoa ont été testées dans un phytotron (27 °C avec photopériode de 16 heures; intensité lumineuse: 5380 lux). Nous avons trouvé de nettes différences entre les types de lésions locales, le degré de différenciation des lésions, leur taille et période d’incubation (tableau 1, figure 1). Cependant, aucune différence perceptible entre les 3 isolats de PVS testés n’a pu être faite quant aux réactions des 8 souches deC. quinoa. Dans une comparison détaillée, ‘valdivia’ l’une des souches les plus sensibles, a provoqué de nombreuses lésions locales 5 jours après inoculation. Les lésions locales sur ‘sélection C’ étaient plus caractéristiques que celles sur ‘valdivia’ (figure 2). Ainsi, nous pouvons conclure que ‘valdivia’ et ‘sélection C’ conviennent toutes deux comme plantes pour le dosage de PVS. Le choix de l’une ou l’autre de ces souches dépend des buts particuliers de chaque étude.

     

Reliable enzyme-linked immunosorbent assay for the determination of soybean proteins in processed foods

Among allergenic foods, soybean is known as a food causing adverse reactions in allergenic patients. To clarify the validity of labeling, the specific and sensitive detection method for the analysis of the soybean protein would be necessary. The p34 protein, originally characterized to be p34 as an oil-body associated protein in soybean, has been identified as one of the major allergenic proteins and named Gly m Bd 30K. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of the soybean protein in processed foods was developed using polyclonal antibodies raised against p34 as a soybean marker protein and the specific extraction buffer for extract. The developed sandwich ELISA method was highly specific for the soybean protein. The limit of detection (LOD) and the limit of quantification (LOQ) of the developed ELISA were 0.47 ng/mL (equivalent to 0.19 microg/g in foods) and 0.94 ng/mL (equivalent to 0.38 microg/g in foods), respectively. The recovery ranged from 87.7 to 98.7%, whereas the intra- and interassay coefficients of variation were less than 4.2 and 7.5%, respectively. This study showed that the developed ELISA method is a specific, precise, and reliable tool for the quantitative analysis of the soybean protein in processed foods.     

Seasonal changes of nitrate concentrations in baseflow headwaters of coniferous forests in Japan: A significant indicator for N saturation

Understanding the seasonal and regional patterns of nitrogen (N) components in the headwaters of forested watersheds is important for forests management. Here, we investigated the NO₃-N concentration and its seasonal variations in the baseflow headwaters in Japanese coniferous forests with different N saturation status in five regions (i.e., Nagano, Tokyo, Aichi, Kochi and Mie). We found that the ratios of NO₃-N to DON were significantly higher in the N-saturated regions including Nagano (14.1 ± 2.2) and Tokyo (16.5 ± 4.1), compared with the regions, which didn't experience N saturation including Aichi (1.4 ± 0.2), Kochi (5.1 ± 1.8), and Mie (2.2 ± 0.5). In comparison with the regions without experiencing N saturation, the relatively higher NO₃-N concentration, as well as its contrastive variation between growing season and dormant season, was also characteristic of the seasonal NO₃-N concentration in the N-saturated regions. Our findings have indicated that NO₃-N concentration, its seasonal variations, and the ratio of NO₃-N to DON, are the better and applicable indicators for evaluating N saturation status in Japanese coniferous forests.     

Pole and global shape of 25143 Itokawa

The locations of the pole and rotation axis of asteroid 25143 Itokawa were derived from Asteroid Multiband Imaging Camera data on the Hayabusa spacecraft. The retrograde pole orientation had a right ascension of 90.53 degrees and a declination of -66.30 degrees (52000 equinox) or equivalently 128.5 degrees and -89.66 degrees in ecliptic coordinates with a 3.9 degrees margin of error. The surface area is 0.393 square kilometers, the volume is 0.018378 cubic kilometers with a 5% margin of error, and the three axis lengths are 535 meters by 294 meters by 209 meters. The global Itokawa revealed a boomerang-shaped appearance composed of two distinct parts with partly faceted regions and a constricted ring structure.     

Optimal sap flux sensor allocation for stand transpiration estimates: a non-dimensional analysis

Key message

Measuring between-tree variations in sap flux density rather than azimuthal variations should be prioritized for reliable stand transpiration estimates based on sap flux methods.

Context

Stand transpiration (E) estimated using sap flux methods includes uncertainty induced by azimuthal variations and between-tree variations in sap flux density (F).

Aims

This study examines whether or not measuring F for two or more azimuthal directions to cover azimuthal variations in F leads to more reliable E estimates. This examination was done under the assumption that azimuthal and between-tree variations in F are not systematic and when a limited number of sensors are available.

Methods

We first non-dimensionalized the theoretical framework established by a previous study and developed a general hypothesis. We then validated the hypothesis quantitatively by numerical experiments.

Results

The non-dimensionalized theory allowed us to hypothesize that measuring F for one azimuthal direction would reduce uncertainty in E estimates more effectively than measuring F for two or more azimuthal directions. Results of the numerical experiments were found to support this hypothesis.

Conclusion

When the aforementioned assumptions are satisfied, allocating sensors to measure F for one azimuthal direction to cover between-tree variations in F always leads to more reliable E estimates.