Magnetic superstructure in the two-dimensional quantum antiferromagnet SrCu2(BO3)2

We report the observation of magnetic superstructure in a magnetization plateau state of SrCu2(BO3)2, a frustrated quasi-two-dimensional quantum spin system. The Cu and B nuclear magnetic resonance (NMR) spectra at 35 millikelvin indicate an apparently discontinuous phase transition from uniform magnetization to a modulated superstructure near 27 tesla, above which a magnetization plateau at 1/8 of the full saturation has been observed. Comparison of the Cu NMR spectrum and the theoretical analysis of a Heisenberg spin model demonstrates the crystallization of itinerant triplets in the plateau phase within a large rhomboid unit cell (16 spins per layer) showing oscillations of the spin polarization. Thus, we are now in possession of an interesting model system to study a localization transition of strongly interacting quantum particles.     

Trienoic fatty acids and plant tolerance of high temperature

The chloroplast membrane of higher plants contains an unusually high concentration of trienoic fatty acids. Plants grown in colder temperatures have a higher content of trienoic fatty acids. Transgenic tobacco plants in which the gene encoding chloroplast omega-3 fatty acid desaturase, which synthesizes trienoic fatty acids, was silenced contained a lower level of trienoic fatty acids than wild-type plants and were better able to acclimate to higher temperatures.     

Malignant Lymphoma with Severe Infiltrative Growth into Skeletal Muscles in WBN/Kob Rats

Although spontaneously occurring neoplasms have been reported repeatedly in F344, SD and Wistar rats, which are commonly used strains for routine toxicologic and carcinogenicity studies, there are only a few reports of malignant lymphoma or lymphatic leukemia except for large granular lymphocytic leukemia (LGL) in F344 rats. Malignant lymphoma (lymphosarcoma) is thought to be uncommon in F344 rats. The authors encountered malignant lymphomas of the non-LGL leukemia type with characteristic pathologic features in WBN/Kob rats. The mean age at onset of the disease in all 13 affected rats (8 males and 5 females) was about 60 weeks. Common and characteristic clinical signs were abnormal gait with hind limb paralysis. Macroscopically, the enlargement of the lymph nodes, spleen and liver was slight to moderate. Scattered multiple white-to-gray nodules encompassed the aorta and assumed a bead-like appearance near the thoracic and lumbar vertebrae. Histopathologically, neoplastic proliferative changes were predominant in the bone marrow tissue of the entire body, and many tumor cells infiltrated the spleen and several lymph nodes. The most striking histological features were constant and severe infiltration of tumor cells in the adipose tissue and skeletal muscle adjacent the thoracic and lumber vertebrae. Immunohistochemically, all tumor cells were positive for B-cell markers (PAX-5, CD79a and CD45) and negative for CD3. From the results of immunohistochemistry and morphological examination, these tumors were diagnosed as malignant B-cell lymphomas.     

Passive immunization with monoclonal antibodies: effects on Haemaphysalis longicornis tick infestation of BALB/c mice

Tick vaccine development plays an important role in current tick control strategies. Previously, we have produced three different isotypes of monoclonal antibodies (mAbs) which recognized a midgut protein of adult Haemaphysalis longicornis. These mAbs, typed as IgG1, 2a, and 2b, reacted with a 76 kDa surface protein of midgut cells. We speculated that the 76 kDa protein may be an unknown antigen for a tick vaccine and the three mAbs may work as probes to clone the protein. In this study, to test whether these three isotypes have anti-tick effects and if so which works more effectively, we conducted passive immunization in BALB/c mice with each of the mAbs, and infested the mice with adult ticks. All isotypes significantly reduced the number of hatched larvae, compared to controls, however, no differences in the magnitude of the reduction were observed among the three.     

Production and characterization of monoclonal antibodies against midgut of ixodid tick,Haemaphysalis longicornis

There are concerted efforts toward development of tick vaccines to replace current chemical control strategies that have serious limitations [Parasitologia 32 (1990) 145; Infectious Disease Clinics of North America (1999) 209-226]. In this study, monoclonal antibodies (mAbs) specific to Haemaphysalis longicornis midgut proteins were produced and characterized. Eight antibody-secreting hybridomas were cloned and the mAbs typed as IgG1, IgG2a and IgG2b. On immunoblots, all mAbs reacted with a midgut protein band of about 76 kDa. All mAbs uniformly immunogold-stained the surface or epithelial layers of H. longicornis midgut and endosomes. Adult ticks (50%) that fed on an ascitic mouse producing the IgGs developed a red coloration and did not oviposit. As such, the 76 kDa protein that reacted with the mAbs could, therefore, be a potential candidate for tick vaccine development.     

Einfluß des Bodengefüges auf Wurzelwachstum und Phosphataufnahme von Sommerweizen

Influence of Soil Structure on Root Growth and P Uptake of Spring Wheat The effect of soil structure (fine aggregat, coarse aggregate and compacted structure) on root growth, root morphology, and P availability of spring wheat (Triticum aestivum L.) was studied in pot and split root experiments using three soils (2 × Alfisol-Udalf, Alluvium). CAL-soluble P was 63–90 mg P · kg^?1 soil, indicating a sufficient P supply. Root length, root surface, root fresh weight, shoot weight, and seed yield were decreased due to coarse aggregate and compacted structure. Roots were significantly thickened and roots hairs were longer in the fine aggregate structure than in the compacted and coarse aggregate structures. P concentration in the shoot and P uptake of spring wheat growing in the coarse aggregate and compacted structure were lower because root growth was decreased. In the split root experiment, in contrast to pot experiment, P uptake was lower in the compacted than in the fine aggregate treatment. The results demonstrate that P availability was influenced by soil structure via the influence on root growth and thus access of roots to P.     

Microfibril angle and density of hinoki (Chamaecyparis obtusa) trees in 15 half-sib families in a progeny test stand in Kyushu, Japan

It was previously believed in Japan that the wood qualities of hinoki (Chamaecyparis obtusa) were superior to sugi (Cryptomeria japonica). However, few studies of wood properties such as MFA (microfibril angle of S₂ layer in secondary wall of tracheid) have been completed for hinoki. Some reports have found that hinoki plus tree families have similar mechanical properties to sugi. Here we report the characteristics of MFA and density of hinoki half-sib families in a progeny test stand. There were significant differences in MFA and density between families. The wood properties of two families, Nakatsu 3 and Kanzaki 5, are stable in radial pattern and suitable for structural use. Early selection of hinoki families by MFA and density may be difficult. Effects of MFA and density on E _d (dynamic modulus of elasticity) of logs differed between families. The effects of growth rate on MFA and density differed between families and also between juvenile and mature wood. The faster growth rate in Nakatsu 3 appeared to improve wood properties and increase E _d of logs, although in many other families, faster growth rate had negative effects on desirable wood properties for structural use.