Crystalline, Mixed-Valence Manganese Analogue of Prussian Blue: Magnetic, Spectroscopic, X-ray and Neutron Diffraction Studies

The compound of stoichiometry Mn(II)3[Mn(III)(CN)6]2·zH2O (z = 12−16) (1) forms air-stable, transparent red crystals. Low-temperature single crystal optical spectroscopy and single crystal X-ray diffraction provide compelling evidence for N-bonded high-spin manganese(II), and C-bonded low-spin manganese(III) ions arranged in a disordered, face-centered cubic lattice analogous to that of Prussian Blue. X-ray and neutron diffraction show structured diffuse scattering indicative of partially correlated (rather than random) substitutions of [Mn(III)(CN)6] ions by (H2O)6 clusters. Magnetic susceptibility measurements and elastic neutron scattering experiments indicate a ferrimagnetic structure below the critical temperature Tc = 35.5 K.

Electrospray tandem mass spectrometry of mixed-sequence RNA/DNA oligonucleotides

The fragmentation of electrospray-generated multiply deprotonated RNA and mixed-sequence RNA/DNA pentanucleotides upon low-energy collision-induced dissociation (CID) in a hybrid quadrupole time-of-flight mass spectrometer was investigated. The goal of unambiguous sequence identification of mixed-sequence RNA/DNA oligonucleotides requires detailed understanding of the gas-phase dissociation of this class of compounds. The two major dissociation events, base loss and backbone fragmentation, are discussed and the unique fragmentation behavior of oligoribonucleotides is demonstrated. Backbone fragmentation of the all-RNA pentanucleotides is characterized by abundant c-ions and their complementary y-ions as the major sequence-defining fragment ion series. In contrast to the dissociation of oligodeoxyribonucleotides, where backbone fragmentation is initiated by the loss of a nucleobase which subsequently leads to the formation of the w- and [a-base]-ions, backbone dissociation of oligoribonucleotides is essentially decoupled from base loss. The different behavior of RNA and DNA oligonucleotides is related to the presence of the 2'-hydroxyl substituent, which is the only structural alteration between the DNA and RNA pentanucleotides studied. CID of mixed-sequence RNA/DNA pentanucleotides results in a combination of the nucleotide-typical backbone fragmentation products, with abundant w-fragment ions generated by cleavage of the phosphodiester backbone adjacent to the deoxy building blocks, whereas backbone cleavage adjacent to ribonucleotides induces the formation of c- and y-ions. (C) 2002 American Society for Mass Spectrometry.

Geographic variation in floral allometry suggests repeated transitions between selfing and outcrossing in a mixed mating plant

• Premise of the study: Isometric and allometric scaling of a conserved floral plan could provide a parsimonious mechanism for rapid and reversible transitions between breeding systems. This scaling may occur during transitions between predominant autogamy and xenogamy, contributing to the maintenance of a stable mixed mating system. • Methods: We compared nine disjunct populations of the polytypic, mixed mating species Oenothera flava (Onagraceae) to two parapatric relatives, the obligately xenogamous species O. acutissima and the mixed mating species O. triloba. We compared floral morphology of all taxa using principal component analysis (PCA) and developmental trajectories of floral organs using ANCOVA homogeneity of slopes. • Key results: The PCA revealed both isometric and allometric scaling of a conserved floral plan. Three principal components (PCs) explained 92.5% of the variation in the three species. PC1 predominantly loaded on measures of floral size and accounts for 36% of the variation. PC2 accounted for 35% of the variation, predominantly in traits that influence pollinator handling. PC3 accounted for 22% of the variation, primarily in anther–stigma distance (herkogamy). During O. flava subsp. taraxacoides development, style elongation was accelerated relative to anthers, resulting in positive herkogamy. During O. flava subsp. flava development, style elongation was decelerated, resulting in zero or negative herkogamy. Of the two populations with intermediate morphology, style elongation was accelerated in one population and decelerated in the other. • Conclusions: Isometric and allometric scaling of floral organs in North American Oenothera section Lavauxia drive variation in breeding system. Multiple developmental paths to intermediate phenotypes support the likelihood of multiple mating system transitions.

White lupin (Lupinus albus L.), the neglected multipurpose crop: Its production and utilization in the mixed crop-livestock farming system of Ethiopia

A survey was conducted to generate holistic information on the production and utilization of local white lupin in two lupin growing districts, namely, Mecha and Sekela, representing mid and high altitude areas, respectively in North-western Ethiopia. During the survey, two types of participatory rural appraisal (PRA) techniques, namely, individual farmer interview (61 farmers from Mecha and 51 from Sekela) and group discussion (with 20 farmers from each district) were employed. There are significant differences (P<0.05) between the two study districts for the variables like total land holding, frequency of ploughing during lupin planting, days to maturity, lupin productivity, and number of days of soaking lupin in running water. However, there are no significant differences (P>0.05) between the two study districts for the variables like land allocated for lupin cultivation, lupin seed rate, lupin soaking at home, lupin consumption per family per week and proportion of lupin used for household consumption. The use of the crop as livestock feed is negligible due to its high alkaloid content. It is concluded that the local white lupin in Ethiopia is a valuable multipurpose crop which is being cultivated in the midst of very serious shortage of cropland. Its ability to maintain soil fertility and serve as a source of food in seasons of food scarcity makes it an important crop. However, its bitter taste due to its high alkaloid content remains to be a big challenge and any lupin improvement strategy has to focus on minimizing the alkaloid content of the crop.

Tumour border configuration in colorectal cancer: proposal for an alternative scoring system based on the percentage of infiltrating margin.

AIMS Information on tumour border configuration (TBC) in colorectal cancer (CRC) is currently not included in most pathology reports, owing to lack of reproducibility and/or established evaluation systems. The aim of this study was to investigate whether an alternative scoring system based on the percentage of the infiltrating component may represent a reliable method for assessing TBC. METHODS AND RESULTS Two hundred and fifteen CRCs with complete clinicopathological data were evaluated by two independent observers, both 'traditionally' by assigning the tumours into pushing/infiltrating/mixed categories, and alternatively by scoring the percentage of infiltrating margin. With the pushing/infiltrating/mixed pattern method, interobserver agreement (IOA) was moderate (κ = 0.58), whereas with the percentage of infiltrating margins method, IOA was excellent (intraclass correlation coefficient of 0.86). A higher percentage of infiltrating margin correlated with adverse features such as higher grade (P = 0.0025), higher pT (P = 0.0007), pN (P = 0.0001) and pM classification (P = 0.0063), high-grade tumour budding (P < 0.0001), lymphatic invasion (P < 0.0001), vascular invasion (P = 0.0032), and shorter survival (P = 0.0008), and was significantly associated with an increased probability of lymph node metastasis (P < 0.001). CONCLUSIONS Information on TBC gives additional prognostic value to pathology reports on CRC. The novel proposed scoring system, by using the percentage of infiltrating margin, outperforms the 'traditional' way of reporting TBC. Additionally, it is reproducible and simple to apply, and can therefore be easily integrated into daily diagnostic practice.

Combined ATRX/IDH1 immunohistochemistry predicts genotype of oligoastrocytomas

AIMS To assess whether in oligoastrocytomas ATRX deficiency - as a surrogate of the alternative lengthening of telomeres (ALT) pathway - has a role in predicting the presence or absence of loss of heterozygosity of 1p and 19q (LOH), the genetic signature of oligodendroglial differentiation and a favourable prognostic marker. METHODS AND RESULTS A series of 54 oligoastrocytomas were investigated by immunohistochemistry as well as microsatellite analysis for LOH 1p19q. Genetic findings were correlated with morphological assessment. CONCLUSIONS ATRX deficiency was mutually exclusive with LOH. Conversely, ATRX-proficient tumours immunoreactive for R132H-mutant isocitrate dehydrogenase 1 (IDH1) showed a high rate (85%) of LOH. A more oligodendroglioma-like morphology was associated with a higher rate of LOH even in the morphologically ambiguous group of oligoastrocytomas. Our findings support the concept that oligoastrocytomas represent a morphological grey zone rather than a group of truly "mixed" or "intermediate" tumours. More precise classification of diffuse gliomas may also improve grading of borderline cases. We propose an immunohistochemical algorithm for classification of morphologically ambiguous diffuse gliomas. This article is protected by copyright. All rights reserved.