bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry and biology of Okinawan marine natural products
Authors: Kobayashi Jun'ichi 
Published: May 2009

Abstract
Marine macro- and micro-organisms collected in Okinawa are good sources of compounds with intriguing structures and interesting biological activities. Synthetic hybrid molecules of caffeine and eudistomin D from tunicates Eudistoma sp. were found to show better potency as adenosine receptor ligands than caffeine, and one of them exhibits potent activity for adenosine receptors tested, especially for A3 subtype. Potent cytotoxic polyene macrolides from a tunicate Cystodytes sp. were found to be potent osteoclast inhibitors and to inhibit vacuolar type H+-ATPase (V-ATPase) of both mammalian and yeast cells. Amphidinolactones A and B are new macrolides from a dinoflagellate Amphidinium sp., and a potent cytotoxic macrolide from another strain was found to target actin cytoskeleton. Theonezolide A, a long-chain polyketide from a sponge Theonella sp., induces a drastic shape change in platelets by reorganization of microtubules. The stereochemistry of many chiral centers in theonezolide A was elucidated by spectral data and chemical means. Metachromins L-Q are new sesquiterpenoid quinones with an amino acid residue, while nakijiquinones E and F were the first dimeric sesquiterpenoid quinones possessing a 3-aminobenzoate moiety. Halichonadin E is the first hetero-dimeric sesquiterpenoid with eudesmane and aromadendrane skeletons linked through a urea fragment isolated from a sponge Halichondria sp. Pyrinadine A and nakinadine A are novel bis-pyridine alkaloids from sponges, while nagelamides are new bromopyrrole alkaloids from a sponge Agelas sp. Here, the structures and bioactivities of these interesting marine natural products will be described.
Biosynthesis and biosynthetic engineering of calcium-dependent lipopeptide antibiotics
Authors: Micklefield Jason 
Published: May 2009

Abstract
Biosynthetic engineering involves the reprogramming of genes that are involved in the biosynthesis of natural products to generate new "non-natural" products, which might otherwise not exist in nature. Potentially this approach can be used to provide large numbers of secondary metabolites variants, with altered biological activities, many of which are too complex for effective total synthesis. Recently we have been investigating the biosynthesis of the calcium-dependent antibiotics (CDAs) which are members of the therapeutically relevant class of acidic lipopeptide antibiotics. CDAs are assembled by nonribosomal peptide synthetase (NRPS) enzymes. These large modular assembly-line enzymes process intermediates that are covalently tethered to peptidyl carrier protein (PCP) domain bonds bonds, which makes them particularly amenable to reprogramming. The CDA producer, Streptomyces coelicolor, is also a genetically tractable model organism which makes CDA an ideal template for biosynthetic engineering. To this end we have elucidated many of the key steps in CDA biosynthesis and utilized this information to develop methods that have enabled the engineered biosynthesis of wide range of CDA-type lipopeptides.
Ion channel complex of antibiotics as viewed by NMR
Authors: Murata Michio , Kasai Yusuke , Umegawa Yuichi , Matsushita Naohiro , Tsuchikawa Hiroshi , Matsumori Nobuaki , Oishi Tohru 
Published: May 2009

Abstract
Amphotericin B (AmB) exerts its pharmacological effects by forming a barrel-stave assembly in fungal membranes. To examine the interaction between AmB and ergosterol or cholesterol, 13C- and 19F-labeled covalent conjugates were prepared and subjected to solid-state NMR measurements. Using rotor-synchronous double resonance experiments such as REDOR and RDX, we estimated the distance between the fluorine atom and its nearest carbon in the heptaene moiety to be less than 8.6 Å, indicating that the B ring of ergosterol comes close to the AmB polyene moiety. Conformational search of the AmB-ergosterol conjugate using the NMR-derived constraints suggested that ergosterol molecules surround the AmB assembly in contrast to the conventional image where ergosterol is inserted into AmB molecules. AmB-AmB bimolecular interaction was examined by using 13C- and 19F-labeld AmBs in dimyritoylphosphatidylcholine membrane without sterols. 13C-19F dipolar interactions deriving from both head-to-head and head-to-tail orientations were observed in the REDOR experiments. The interactions between AmB and acyl chains of the phospholipid were also detected.
Chemical warfare in the sea: The search for antibiotics from Red Sea corals and sponges
Authors: Kelman Dovi , Kashman Yoel , Hill Russell T. , Rosenberg Eugene , Loya Yossi 
Published: May 2009

Abstract
Marine sponges and corals are widely recognized as rich sources of novel bioactive natural products. These organisms are frequently colonized by bacteria. Some of these bacteria can be pathogenic or serve as beneficial symbionts. Therefore, these organisms need to regulate the bacteria they encounter and resist microbial pathogens. One method is by chemical defense. Antimicrobial assays performed with extracts of 23 Red Sea corals and sponges against bacteria isolated from their natural environment revealed considerable variability in antimicrobial activity. Soft corals exhibited appreciable activity; sponges showed variability, and stony corals had little or no activity. Among the soft corals, Xenia macrospiculata exhibited the highest activity. Bioassay-directed fractionation of the extract indicated that the activity was due to a range of compounds, one of which was isolated and identified as the diterpene desoxyhavannahine. Among the sponges, Amphimedon chloros exhibited strong activity. Bioassay-directed fractionation resulted in the isolation of the pyridinium alkaloid antibiotics, the halitoxins and amphitoxins. These compounds showed selective activity against specific bacteria, rather than being broad-spectrum. They were highly active against seawater bacteria, whereas bacteria associated with the sponge were resistant. This selective toxicity may be important in enabling certain bacteria to live in close association with their sponge host while it maintains a chemical defense against microbial pathogenesis. The halitoxin-resistant bacteria were identified by 16S rRNA gene analysis as Alphaproteobacteria, closely related to other Alphaproteobacteria isolated from various marine sponges. The study of microbial communities associated with sponges and corals has important implications for the production of symbiont-derived bioactive compounds and for the use of corals and sponges as source material for microbial diversity in screening programs for natural products.
Quantitative chemical indicators to assess the gradation of compression wood
Authors: Nanayakkara Bernadette , Manley-Harris Merilyn , Suckling Ian D. , Donaldson Lloyd A. 
Published: May 2009

Abstract
A chemistry-based parameter has been sought for determining the gradation of compression wood (CW), i.e., the severity, in tissues of Pinus radiata wood. Fluorescence microscopy was the reference for characterisation of the tissues containing CW. The collected material contained CW of varying severity, beginning with normal wood (NW containing no CW), continuing with material with some features of CW (CW of mild severity, MCW) and ending up with a material with pronounced features of CW (CW of high severity, SCW). Matching opposite wood (OW) was also included in the study. The chemical analyses included lignin determination, sugar analysis in the acid hydrolysate, thioacidolysis, 31P-NMR spectroscopic analysis and steric exclusion chromatography of thioacidolysis products. As the severity of CW changed progressively from NW through MCW to SCW, all chemical parameters changed concurrently. In particular, levels of galactose and lignin increased, while those of glucose and mannose decreased. The amounts of p-hydroxyphenyl β-ethers released by chemical degradation and uncondensed p-hydroxyphenyl C-9 units also increased at elevated CW severity levels. The amounts of galactose and the p-hydroxyphenyl content of the lignin correlated linearly with lignin for CW samples. The chemical differences between CW and OW in the stem, branch and seedling were similar, i.e., they are independent of the morphological origin of the sample. Parameters based on the p-hydroxyphenyl unit content appear the most suitable chemical indicators of CW severity, as they are least sensitive to the sample's morphological origin and their response to CW severity is high.
The relationship found between fibre length and viscosity of three different commercial kraft pulps
Authors: Lapierre Luc , Bouchard Jean , Berry Richard 
Published: May 2009

Abstract
In this report, two softwood kraft pulps, one originating from chips and the other from sawdust, and a hardwood kraft pulp originating from chips were fractionated individually with regard to fibre length using a Bauer-McNett apparatus. The fibre length, the coarseness, the 0.5% viscosity and the intrinsic viscosity were measured on all fractions and whole pulps. For every pulp, there was a unique positive relation between fibre length and viscosity, and also between fibre length and coarseness. Since fibre length has a direct impact on pulp strength, viscosity measurement can provide an indirect method to predict pulp strength. This relationship between the two datasets increases the value of viscosity as an analytical tool.
Colour in thermally modified wood of beech, Norway spruce and Scots pine. Part 2: Property predictions from colour changes
Authors: González-Peña Marcos M. , Hale Michael D.C. 
Published: May 2009

Abstract
In the woodworking industry, image analysis is routinely used for quality control and for matching and classification during various processes. An extension of these automated systems for the prediction of physical properties of thermally modified wood (TMW) is enticing, because to date there is no generalised procedure for the quality assurance of TMW. In this work, the feasibility of predicting 13 physical parameters from the analysis of colour changes is demonstrated using small thermally modified specimens of three wood species. Simple linear regression models for anti-swelling efficiency, nominal density, heat-induced weight loss and 10 strength parameters in six forms of stress were all very or highly significant, with R2 statistics for the best predictor from 0.24 to 0.94. ΔE* was found to be a better predictor than ΔL* for most properties. Multiple linear regression with 11 colour variables increased the prediction ability of most models in terms of R2, although these improvements varied with the property and species concerned. The best models altogether were obtained by partial least squares regression, with relative prediction error values >0 in all cases. Our results demonstrate that physical properties of small specimens of TMW can be efficiently predicted with only one after treatment measurement of colour in the CIEL*a*b* colour space by means of image analysis of TMW surfaces. We anticipate that our approach would be a starting point for more refined modelling of physical properties of larger wood members and other properties of interest in TMW (e.g., decay resistance).
Colour in thermally modified wood of beech, Norway spruce and Scots pine. Part 1: Colour evolution and colour changes
Authors: González-Peña Marcos M. , Hale Michael D.C. 
Published: May 2009

Abstract
Colour evolution and colour changes were analysed from surface images of small specimens of three thermally-modified timber species using the CIEL*a*b* colour space. Upon heat exposure, the wood substance became orange and then approached grey irrespective of species; this was accompanied by a steady reduction in lightness. Colour changes were similar in the three woods at any given level of heat-induced weight loss (WL), whilst changes in the three coordinates of the CIEL*a*b* space in function of WL were different regardless of the wood species. For ΔL*, the profile was curvilinear and monotonous, while Δa* and Δb* bear a complex, non-linear profile. In turn, ΔE* was found to be highly influenced by the behaviour of ΔL*. It is proposed that ΔE* in thermally modified wood originates from chemical changes in the main wood polymers, more so in lignin than in polysaccharides, due to the darkening of the lignin itself. This was associated with the generation of chromophoric groups, mainly the increase in carbonyl groups appearing in the Fourier transform infrared spectra of lignin between 1710 and 1600 cm-1, particularly the emergence of quinone species.
Topochemical investigations of cell walls in developing xylem of beech (Fagus sylvatica L.)
Authors: Prislan Peter , Koch Gerald , Čufar Katarina , Gričar Jožica , Schmitt Uwe 
Published: May 2009

Abstract
Formation and lignification of xylem cells in mature beech (Fagus sylvatica L.) trees growing in a forest site in Slovenia (46° N, 14°40′ E, 400 m a.s.l.) were studied on the cellular and subcellular level. Samples containing the cambial zone and developing xylem were taken from six beech trees every week throughout the 2006 vegetation period. Cell wall thickening and lignification in individual cell wall layers and cell types were determined by light microscopy, cellular UV-microspectrophotometry and transmission electron microscopy, respectively. Cell division started between the 18th and the 24th of April 2006. Lignification began in the newly formed xylem tissue on the 2nd of May. After 1 month, the developing earlywood portion contained fully differentiated vessels with completed wall deposition and lignification, and differentiated fibres and axial parenchyma became visible after 2 months. At the end of cambial cell division on the 9th August, the differentiation of the most recently formed fibres in the terminal zone of the growth ring continued for approximately 4 weeks. This indicates that the process of lignification in earlywood is slower than in latewood. The high temporal resolution of the investigated processes and the combination of the above-mentioned microscopic techniques provides a detailed insight into the process of cell wall thickening and lignification of woody tissue in beech.
Neutron attenuation coefficients for non-invasive quantification of wood properties
Authors: Mannes David , Josic Lidija , Lehmann Eberhard , Niemz Peter 
Published: May 2009

Abstract
Attenuation coefficients and mass attenuation coefficients of wood were determined theoretically and experimentally for thermal and cold neutrons. Experiments were carried out at the neutron imaging facilities at the Paul Scherrer Institute, Villigen (CH). For the calculation of theoretical attenuation coefficients, only the three main elemental components (carbon, oxygen and hydrogen) were taken into consideration. While hydrogen accounts only for 6% (by wt) of wood, over 90% of the attenuation can be attributed to this element. Nitrogen and other trace elements were estimated to have a negligible impact on the theoretical attenuation coefficient. For the experimental determination of the attenuation coefficients, samples from different European and tropical wood species were tested in order to examine the influence of density and extractives content. Experimental results show a very strong linear correlation between attenuation coefficient and wood density irrespective of the tested species and extractives content that play only a minor role. As neutrons are very susceptible to scattering, it is necessary to apply a scattering correction if a quantitative evaluation is intended.
Nicht-invasive pränatale Diagnostik fetaler chromosomaler Aneuploidien mittels Nukleinsäureanalyse des mütterlichen Plasmas / Noninvasive prenatal diagnosis of fetal chromosomal aneuploidies by maternal plasma nucleic acid analysis1)
Authors: Lo Y.M. Dennis , Chiu Rossa W.K. 
Published: May 2009

Zusammenfassung
Die Entdeckung zirkulierender zellfreier fetaler Nukleinsäuren im mütterlichen Plasma eröffnet neue Möglichkeiten für die nicht-invasive pränatale Diagnostik. Die mögliche Anwendung dieser Technologie für den nicht-invasiven pränatalen Nachweis fetaler chromosomaler Aneuploidien stellt dabei einen besonders interessanten Aspekt dieses Bereiches dar. Die größte Herausforderung besteht darin, dass zellfreie fetale Nukleinsäuren nur einen kleinen Bruchteil der gesamten Nukleinsäuren im mütterlichen Plasma darstellen.
Es wurde eine Literatur-Recherche durchgeführt, die zeigte, dass die Untersucher Methoden angewandt haben, die auf der physischen und molekularen Anreicherung fetaler Nukleinsäure-Targets aus mütterlichem Plasma basieren. Die erstere umfasst die Verwendung der Größenfraktionierung der DNA sowie der – allerdings umstrittenen – Methode der Formaldehyd-Behandlung. Letztere wurde durch die Entwicklung fetaler epigenetischer und fetaler RNA-Marker erreicht. Der Aneuploidiestatus des Fetus wurde mittels der Analyse des Allelverhältnisses der fetalen epigenetischen und RNA-Marker im Plasma erforscht. Es hat sich gezeigt, dass die digitale PCR eine hohe Präzision für Analysen des Allelverhältnisses und der relativen Chromosomendosis bietet.
Nach 10 Jahren Arbeit konnte in Studien mit kleinen Probenumfängen die theoretische und praktische Durchführbarkeit des Nachweises pränataler fetaler chromosomaler Aneuploidie mittels der Analyse von Nukleinsäuren im Plasma nachgewiesen werden. Es werden jedoch größere unabhängige Studien nötig sein, um diese ersten Beobachtungen zu bestätigen. Falls sich diese größer angelegten Studien als erfolgreich erweisen, ist zu erwarten, dass die molekulare nicht-invasive pränatale Diagnose der wichtigsten chromosomalen Aneuploidien durch die Weiterentwicklung neuer fetaler DNA/RNA-Marker und neuer analytischer Methoden in naher Zukunft zur Routine werden könnte.
Thromboembolische Erkrankungen in der Hämatologie und Onkologie / Thrombotic disease in cancer patients
Authors: Hart Christina , Andreesen Reinhard , Hahn Joachim R. 
Published: May 2009

Zusammenfassung
Das Auftreten eines thromboembolischen Ereignisses ist eine häufige und schwerwiegende Komplikation bei Tumorpatienten und stellt eine wichtige Ursache für Morbidität und Mortalität in diesem Patientengut dar. Als Hauptrisikofaktoren für eine Thromboembolie werden neben der Tumorentität und dem Tumorstadium die Hormon- und Chemotherapie, chirurgische Eingriffe sowie die Hospitalisierung angesehen. Sowohl die Aktivierung des Endothels durch inflammatorische Zytokine als auch die Aktivierung des plasmatischen Gerinnungssystems durch die von Tumorzellen produzierten Prokoagulanzien (vor allem Tissue Factor) tragen zur Pathophysiologie der Hyperkoagulabilität bei. Durch Tumorkompression und Einwachsen von Tumorzellen kann es zum Auftreten von Thrombosen an ungewöhnlichen Lokalisationen kommen, zudem werden bei myeloproliferativen Neoplasien gehäuft thrombotische Verschlüsse der Pfortader und der posthepatischen Venen beobachtet. Aufgrund des erhöhten Thromboserisikos muss beim hospitalisierten internistischen und chirurgischen Tumorpatienten auf eine ausreichende Thromboseprophylaxe geachtet werden. Die antikoagulatorische Therapie eines thrombotischen Ereignisses beim Tumorpatienten ist eine Herausforderung, da einerseits ein erhöhtes Risiko für ein Rezidiv der Thromboembolie besteht, und andererseits das Blutungsrisiko – vor allem bei fortgeschrittenen Tumorstadien – erhöht ist.
Color words in literary Russian: Connotations and gender differences in use
Authors: Mostovaia Anna 
Published: May 2009

Abstract
Connotations, or the semantic prosodies of words, are associations acquired through exposure to diverse contexts and may be different for the same language item used by different speakers or groups of speakers. In order to compare connotations of the same language item between groups, tools of comparison are of interest. One such tool is analysis of word frequencies in contexts. This article considers a few hypotheses on gender-linked differences in the use of color words in Russian literary texts. Frequencies of total use of color words, and then of color words modifying nouns referring to body parts, color words modifying nouns referring to clothes, color words which have emotional connotations and of color words used to describe elements of landscape are compared for texts authored by women or by men. For the first three subcategories, it was hypothesized that women on average use more color adjectives in this category than men do. For the last category, it was hypothesized that men use more color adjectives in this category than women do. Two studies have been done to verify these hypotheses. Only the last hypothesis, on greater frequency of color words used to describe landscape in men-authored texts, has been confirmed at a statistically significant level. The hypotheses that women use a greater number of total color adjectives on average, and that women use more color adjectives to modify nouns referring to body parts and clothes, were each confirmed at a marginal level of statistical significance.
Another avenue for investigating the limits of the concept “connotation” uses syntactic tests. One can say that a number of phrases in Russian are (un)acceptable or highly unusual because there exists a recurring connotation connecting a certain color with a certain state of affairs. However, it is questionable whether connotations limited to a sociolinguistic group can be tested using syntactic tests.
Effect of Ta Rich Inclusions and Microstructure Change During Precracking on Bimodal Fracture of Reduced-Activation Ferritic/Martensitic Steels Observed in Transition Range
Authors: Tanigawa Hiroyasu , Sokolov Mikhail A. , Sawahata Atsushi , Hashimoto Naoyuki , Ando Masami , Shiba Kiyoyuki , Enomoto Masato , Klueh Ronald L. 
Published: May 2009

Abstract
The master curve method for analyzing fracture toughness data depends on the assumption that the fracture initiation points are homogeneously distributed and fracture initiation is independent of test temperature. The reduced-activation ferritic/martensitic steels, such as F82H (Fe-8Cr-2W-0.2V-0.04Ta), form Al2O3-Ta(V,Ti)O composite inclusions and its distribution is not homogeneous throughout one heat, and this microstructural inhomogeneity appears to be correlated with bimodal facture of F82H in the transition range. To investigate this possibility, 1TCT fracture toughness specimens of F82H-IEA steel were fatigue precracked and sliced through the specimen thickness for microstructure analysis around the crack. It was found that the crack penetration was straight in the beginning, and then tended to follow a prior austenite grain boundary and finally to branch into two or three different directions. In addition, the microstructures around the crack and ahead of the crack formed a cell structure and became softer than nearby regions, which is typical for fatigue-loaded F82H. Possible mechanisms for how this cell structure ahead of cracks affects fracture toughness are suggested.