bluuebunny/crossref_metadata_2025 huggingface dataset:
Vom Push zum Pull – Der Perspektivewechsel in der Wertschöpfungskette von Forst- und Holzwirtschaft | From push to pull: a shift in the perspective of the value chain of forestry and wood management
Authors: Kaiser Bastian
Published: June 2007

Forestry management – contrary to general public awareness of the matter – is a branch in the process of undergoing dynamic changes. Impulses for these changes come in part from actors and others involved in the «timber value chain» and in part from outside influences. Today, in addition to numerous other effects, these dynamics have led to a situation where«timber chain» supply flows are no longer initiated and mobilised exclusively by what the forest owner fells and offers to customers, but above all by more specialised wood customers with an increasing appetite for wood who articulate their increasing impatience by the means of market forces. Over the years the traditional push effect has thus given way to a pull effect. Forest owners are obliged to react to this development and to seek, together with others-for instance with universities and their faculties-out suitable future strategies. In turn and without a doubt this will impact on the education and training of forest academics, as well as on the self-understanding of forestry employers.
Environmental Policy Making and Landscape-Scale Management
Authors: Master Dennis C. Le
Published: June 2007

The development of landscape ecology, advances in computer technologies, the breaking up of Cold War political barriers,UNCED and the subsequent elaboration of public policy networks in resource conservation and sustainable development have combined to provide a new opportunity for sustainable development in a quality environment across the landscape. The challenge will be transformation of environmental and natural resource policies (rules) into landscape-scale management(practices). Successful implementation of these policies through the networks will require three conditions: the policies must meet well-known and accepted criteria; they must have the full force of law; and they must have a sound ethical foundation. These conditions being met, landscape-scale management can become a reality; the transition from environmental rule to landscape management practice can be complete.
Mutations et enjeux en forêt de Soignes: les années 1900 | Changes and stakes in the forest of Soignes around 1900
Authors: Corvol Andrée
Published: June 2007

The rupture between sylvicultural and agriculturally exploited areas, the regression of semi-urban forests that lost their function as wood producers over the course of the 19th century, the wish to create green spaces for the leisure activities of the population – all these points help to explain the power exercised today by the decision-makers of forest policy, i.e. the elite of the city. The message emerged at the end of the century and was spread by the media from the side of the opposition. Public power was the target of environmental associations. The study examines the reasons for the support the latter managed to rally and the attention paid to them. It also analyses the way in which associations are able use this attention to their own advantage.

The study deals with the progression of the carrying themes including their reorientation and alteration. The associative result was considerable. The combined actions of public power and pressure groups helped the general population to take seriously the problems posed by urban extension to the legacy and history of the forest, particularly in Brussels. While the model might be suited to a capital it could be imprudent to impose it in other forests.
Die Konstruktion von Natur – Central Park neu besichtigt | The Construction of Nature – Central Park Revisited
Authors: Lampugnani Vittorio Magnago
Published: June 2007

In the first half of the 19th century scientific philosophers in the United States, such as Emerson and Thoreau, began to pursue the relationship between man and nature. Painters from the Hudson River School discovered the rural spaces to the north of New York and began to celebrate the American landscape in their paintings. In many places at this time garden societies were founded, which generated widespread support for the creation of park enclosures While the first such were cemeteries with the character of parks, housing developments on the peripheries of towns were later set in generous park landscapes. However, the centres of the growing American cities also need green spaces and the so-called «park movement»reached a first high point with New York's Central Park. It was not only an experimental field for modern urban elements, but even today is a force of social cohesion.
Allocation of Property Rights on Forests through Ownership Reform and Forest Policies in Central and Eastern European Countries
Authors: Bouriaud Laura , Schmithüsen Franz
Published: June 2007

The study applies some concepts of the economics of property rights to the allocation of rights on forests in Central and Eastern European countries. The classification of forest assets, according to their economic characteristics and the analytical framework proposed by SCHLAGER & OSTROM (1992), are used to examine the impact of ownership reforms and policy changes on forest utilisation in the CEE region. It is shown that while reform ownership reforms deal with the formal definition of rights on forestland, new forest policies more properly define the economic rights, e.g. the owner's ability to make a profit from the assets he owns. The conclusions argue that the combination of property and liability rules, applied to ensure the procurement of environmental services, can efficiently allocate forest resources. However, the rules on forest utilisation are formulated collectively in public policy-driven decision making processes in which private forest owners are not yet able to adequately participate. Measures must be adopted to facilitate more effective participation of private land owners in political processes in order to balance the presently ongoing trends of considering forests, irrespective to the legal regime of ownership,as a common-pool resource.
Upper and lower respiratory tract infections by human enterovirus and rhinovirus in adult patients with hematological malignancies
Authors: Parody R. , Rabella N. , Martino R. , Otegui M. , del Cuerpo M. , Coll P. , Sierra J.
Published: June 2007

The impact of human enterovirus (HEV) and human rhinovirus (HRV) respiratory tract infections in adult patients with hematological malignancies has been infrequently reported. We retrospectively studied 31 patients with an upper or lower respiratory tract infection (URTI/LRTI) by HEV (n = 18) or HRV (n = 15). At onset, a LRTI was present in 6 (33%) and 2 (13%) episodes of HEV and HRV infections, respectively, with or without an URTI. Progression to LRTI (pneumonia) from prior URTI was seen in 1 (6%) and 2 (13%) HEV and HRV infections, respectively. The presence of lymphocytopenia (<<0.5 × 109/l) was higher in LRTI by HEV: 4/5 (80%) versus 2/10 (20%) by HRV. Eight of 18 (44%) patients with immunosuppression versus 3/14 (21%) patients with no immunosuppression at the onset of respiratory infection developed a LRTI. Thirteen per cent of patients had associated respiratory infections from bacteria, aspergillus, or CMV. Pulmonary aspergillosis was diagnosed in 20% of HRV infections. Three of 11 patients (27%) with a LRTI died, but pulmonary copathogens were also involved in all cases. In conclusion, HEV and HRV can be associated with LRTI in immunocompromised patients, although their direct impact on mortality is uncertain. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
The effect of high power ultrasound on EPDM gum in extrusion process
Authors: Yun Jushik , Isayev A. I.
Published: June 2007

High power ultrasound treatment of ethylene propylene diene monomer (EPDM) gum in extrusion process was found to affect its structure and properties. In comparison with the original EPDM gum, the ultrasonically treated samples were found to contain some amount of gel with sol having a higher molecular weight, possibly due to chain branching. Gel fraction and dynamic properties of the ultrasonically treated gums and their vulcanizates were measured as a function of processing conditions. Measurements of the stress–strain characteristics, dynamic properties, and hardness of EPDM vulcanizates prepared after treatment indicated a possibility of controlling their properties by varying processing parameters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
The physical properties of hemofiltration module made from polyether sulfone hollow fiber membrane
Authors: He Chun‐Ju , Zhu Si‐Jun , Sun Jun‐Fen , Wang Qing‐Rui
Published: June 2007

Different membrane forming conditions including solid content, spinning solution temperature, the pressure of internal quench medium, concentration of coagulation bath, and winding‐up velocity, etc. have different influence on the structure and physical properties of PES hollow fiber membranes prepared. Membrane properties i.e., void content and water flux decrease with increasing content of PES in the spinning solution. Water flux reaches a maximum while retention reaches a minimum when spinning solution temperature reaches 35°C. Water flux, inner and outer diameters increase and wall thickness decreases with increasing pressure of internal quench medium. Water flux reaches a minimum when the concentration of coagulation bath reaches 20%. The inner diameter of hollow fiber membrane increases and outer diameter does not change with increasing 1st godget velocity. The inner and outer diameters and membrane wall thickness decrease with increasing winding‐up velocity. The clearance of creatinine and urea reaches 92 and 86% respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Fiber and web formation of melt‐blown thermoplastic polyurethane polymers
Authors: Lee Youn Eung , Wadsworth Larry C.
Published: June 2007

The goal of this research was to determine the fiber and web properties of melt‐blown (MB) thermoplastic polyurethane (TPU) polymer as dependent on the MB processing conditions. The relationships between the MB fiber properties and the MB process conditions, such as the die‐to‐collector distance and the velocity of the MB TPU fiber in the spin line, were measured and estimated on the basis of the air velocity and air temperature, respectively. Consequently, this study provided fundamental guidelines of heat, air flow, and distance conditions of the MB process for the production of commercially acceptable MB TPU nonwovens. More specifically, the essential insight into the MB process was fundamentally valid for the MB TPU process; however, the inherent heat sensitivity of the TPU polymer brought more complexity at fiber and web formation than the conventional polyolefin MB process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Comparative photo‐oxidation under natural and accelerated conditions of polypropylene nanocomposites produced by extrusion and injection molding
Authors: Diagne M. , Guèye M. , Dasilva A. , Tidjani A.
Published: June 2007

The photo‐oxidation behavior under natural and accelerated conditions of polypropylene/layered silicate nanocomposite is studied in this article. The nanocomposites are prepared via simple melt mixing (extrusion and injection molding). The structure obtained is very dependent on the preparation mode and the modified clay used; mostly, exfoliation structure is produced. The nanocomposites start their photo‐degradation earlier than the control samples polypropylene and polypropylene‐graft‐maleic anhydride with a higher oxidation rate for specimen produced by injection molding. This is explained by the presence of organiphilic‐modified montmorillonite layers that trap the oxygen, increasing the oxygen pressure in the bulk and leading to a decrease of the induction period. Contrary to the control samples that display auto acceleration in their oxidation kinetics, the nanocomposites show a slight tendency to a plateau indicating a slowing down of the photo‐oxidation process. This is ascribed to oxygen starvation that occurs in the nanocomposite. The acceleration factor is found to be higher for the nanocomposite comparatively of the control samples. With the aid of SF4 and NO treatments, the mechanism of photo degradation was found to be similar in PPgMA and its nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Modification of high ortho novolac resin with diacids to improve its mechanical properties
Authors: İyim Tülin Banu
Published: June 2007

To improve the brittleness of high ortho novolac resins, at first, high ortho novolac resins (N) were synthesized and condensation reactions between N and flexible diacids such as adipic acid (DA4) and azelaic acid (DA7) were carried out with different amounts of diacids, in the presence of zinc acetate as catalyst, in toluene as solvent. To characterize the diacid‐modified resins (MN), FT‐IR analysis, TGA and DSC techniques were used. The morphologies of MN were also investigated. Moldings were prepared from the mixture of MN, fillers, and curing agent hexamethylenetetramine. Mechanical properties of these moldings were also determined. The results showed that high ortho novolac resin was toughened by the incorporation of flexible diacids in the polymer backbone and these modified resins can be used as a matrix resin of composite materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
A water‐soluble supramolecular‐structured photoinitiator between methylated β‐cyclodextrin and 2,2‐dimethoxy‐2‐phenylacetophenone
Authors: Wang Yuanlong , Jiang Xuesong , Yin Jie
Published: June 2007

A water‐soluble supramolecular‐structured photoinitiator (SSPI) was synthesized by supramolecular self‐assembling between methylated β‐cyclodextrin (MβCD) and hydrophobic 2,2‐dimethoxy‐2‐phenylacetophenone (DMPA). The structure of SSPI was characterized by X‐ray diffraction, FTIR, 1H NMR, UV–vis, and fluorescence spectra. The results indicated that MβCD and DMPA had formed 1 : 1 inclusion complex in methanol solution. The binding constant (K) for the complex was 7.51 × 102M−1. SSPI could be dissolved in water easily and its water‐solubility was 15.3 g/100 mL. SSPI was the more efficient photoinitiator than DMPA for the photopolymerization of acrylamide (AM) in homogeneous aqueous system. The conversion for photopolymerization of trimethylolpropane triacrylate system initiated by SSPI was similar to that initiated by DMPA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
In vitro monitoring of surface mechanical properties of poly(L‐lactic acid) using microhardness
Authors: Saiz‐Arroyo C. , Wang Y. , Rodriguez‐Perez M. A. , Alves N. M. , Mano J. F.
Published: June 2007

Poly(L‐lactic acid) (PLLA) was immersed in a simulated body fluid (SBF) solution at 37.5°C for distinct times. The variation of the surface mechanical properties of PLLA samples with immersion time was followed by microhardness. These measurements showed that PLLA microhardness decreased significantly (∼ 60%) after only 30 days of immersion. The results were explained in terms of hydrolytic degradation of the samples. The dependence of microhardness with the applied dwell time was also analyzed. The creep curves were successfully described by a power law. A decrease of the creep constant k as the immersion time increased was found. Differential scanning calorimetry was also used to analyze the changes in the physical properties of PLLA, namely in crystallinity degree (Xc) and glass transition temperature (Tg), as a function of the immersion time in SBF. A significant variation in the crystallinity degree of PLLA, initially nearly amorphous (Xc = 9%), was detected after only 3 days of immersion (Xc = 37%). The interpretation of this behavior was based on the hydrolysis process suffered by PLLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
An in vivo Look at Vertebrate Liver Architecture: Three‐Dimensional Reconstructions from Medaka (Oryzias latipes)
Authors: Hardman Ron C. , Volz Dave C. , Kullman Seth W. , Hinton David E.
Published: June 2007

Understanding three‐dimensional (3D) hepatobiliary architecture is fundamental to elucidating structure/function relationships relevant to hepatobiliary metabolism, transport, and toxicity. To date, factual information on vertebrate liver architecture in 3 dimensions has remained limited. Applying noninvasive in vivo imaging to a living small fish animal model we elucidated, and present here, the 3D architecture of this lower vertebrate liver. Our investigations show that hepatobiliary architecture in medaka is based on a polyhedral (hexagonal) structural motif, that the intrahepatic biliary system is an interconnected network of canaliculi and bile‐preductules, and that parenchymal architecture in this lower vertebrate is more related to that of the mammalian liver than previously believed. The in vivo findings presented advance our comparative 3D understanding of vertebrate liver structure/function, help clarify previous discrepancies among vertebrate liver conceptual models, and pose interesting questions regarding the “functional unit” of the vertebrate liver. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL) Modulates the Expression of Genes Involved in Apoptosis and Cell Cycle in Human Osteoclasts
Authors: Rimondi Erika , Zweyer Marina , Ricci Enrico , Fadda Roberto , Secchiero Paola
Published: June 2007

It has been clearly established that receptor activator of nuclear factor kappa B ligand (RANKL) is a key cytokine involved in the differentiation of osteoclastic precursors of the monocytic/macrophagic lineage. However, relatively little information is available on the ability of RANKL to modulate the expression of genes controlling cell survival/apoptosis and proliferation in human osteoclastic cells in comparison to macrophages. For this purpose, CD14+ human peripheral blood mononuclear cells, which express the cognate high affinity receptor activator of nuclear factor kappa B (RANK), were differentiated along the macrophagic or osteoclastic lineage by adding macrophage‐colony stimulating factor (M‐CSF) or M‐CSF plus RANKL in culture for 12 days. RANKL up‐regulated the expression of the chemokine MIP1α, which potentiates osteoclastic differentiation and simultaneously activated both anti‐apoptotic (Bcl‐2) and pro‐apoptotic (CIDEB, PYCARD, and BAK‐1) genes. Moreover, RANKL markedly up‐regulated cylin D2, while it significantly decreased the levels of cyclin A, cyclin‐dependent kinase 2, and other cyclin‐dependent kinases, in keeping with the notion that end‐stage osteoclasts are nondividing cells. Finally, a long‐term exposure of RANKL up‐regulated the adaptor protein TRAF3 but not TRAF6. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
The Peritoneal Mesothelium Covering the Genital Tract and its Ligaments in the Female Pig Shows Signs of Active Function
Authors: Yániz Jesús Luis , Recreo Pilar , Carretero Teresa , Arceiz Elena , Hunter R.H.F. , López‐Gatius Fernando
Published: June 2007

The aim of this study was to describe the surface features of the peritoneal mesothelium covering the genital tract and adjacent ligaments of the sow to find signs of biosynthetic activation of cells. Surface features of the serosa covering the genital tract and adjacent ligaments from 14 cyclic sows, 7 in the follicular phase and 7 in the luteal phase of the estrous cycle, were examined by histology and scanning electron microscopy. Five additional sows, three in the follicular phase and two in the luteal phase of the estrous cycle, were examined by transmission electron microscopy (TEM). In this study, the presence of cells of the oviductal epithelium in the serosa of the infundibulum and the ampulla, as well as indications of a high functional activity of the mesothelial cells in the areas studied were two aspects that differed from the findings of previous works. Presence of endosalpingeal cells was observed in the serosal surface, showing cyclical variations with a predominance of either ciliated cells during the follicular phase or secretory cells during the luteal phase. Signs of high functional activity of the mesothelial cells included the predominance of cuboidal over flattened cells, a cytoplasm richly supplied with organelles, a dense microvillous coat, numerous primary cilia, and many secretory structures on the surface of cells. These results indicate that the serosa covering the genital area and the adjacent ligaments in the sow has an active epithelium whose coordinating role between reproductive tissues may be far more significant than previously thought. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
A Morphological and 13C NMR Study of the Extramandibular Fat Bodies of the Striped Dolphin (Stenella coeruleoalba)
Authors: Maxia C. , Scano P. , Maggiani F. , Murtas D. , Piras F. , Crnjar R. , Lai A. , Sirigu P.
Published: June 2007

The molecular and histological structure of the fat bodies covering externally the posterolateral region of the jaw of the striped dolphin (Stenella coeruleoalba) was investigated by means of morphological and nuclear magnetic resonance techniques. The analyses of samples belonging to adult and juvenile individuals were performed with the aim of seeking the presence of age‐related differences. In our study, the level of isovalerate (iso5:0) in the extramandibular fat of the juvenile individuals is comparable with those of the adult counterparts; conversely, longer isobranched fatty acids were detected in lower quantities in the juveniles together with a higher degree of unsaturation. The morphologic analyses revealed that, in both adults and juveniles, this fatty tissue is similar to univacuolar adipose tissue. However, in the juveniles, a muscular component was present, whereas only in adult subjects, enlarged and irregularly shaped cavities may be seen within the adipose tissue. These cavities, structurally organized as veins, may regulate blood flow in response to changing water temperature and stabilize thermal gradient within the jaw lipids. These data suggest that the molecular components and the histological organization can indicate a maturation of the organ with age that probably may reflect different sound reception properties. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Conversion of 3‐Arylazo‐5‐phenyl‐2(3H)‐furanones into Other Heterocycles of Anticipated Biological Activity
Authors: Sayed Hayam H. , Hashem Ahmed I. , Yousif Nabil M. , El‐Sayed Waled A.
Published: June 2007

3‐Arylazo‐5‐phenyl‐2(3H)‐furanones 3 were prepared and converted into a variety of heterocyclic systems of synthetic and biological importance. Hydrazine hydrate reacted with furanones as nucleophiles and gave the corresponding acid hydrazides 4. The latter products were used as starting materials for the synthesis of 1,3,4‐oxadiazoles 6, 9, and the 1,2,4‐triazoles 8. Evaluation of the antiviral activity of selected compounds obtained was performed using two viruses: HAV and HSV‐1. Some of the tested compounds showed promising activities.
Finding treasures in frozen cells: new centriole intermediates
Authors: Dutcher Susan K.
Published: June 2007

Centriole duplication has been an area of interest since the late 1800s when Boveri suggested that these structures were central organizers for mitosis and cell division. Two groups1, 2 have delineated a linear pathway for centriole assembly. In C. elegans, Pelletier and coworkers1 have identified intermediates in the pathway using cryo‐electron tomography. Surprising, the first intermediate is a hollow tube of 60 nm that increases in diameter and then elongates before acquiring microtubules. Similar structures have not been observed to date in other centrioles. BioEssays 29:630–634, 2007. © 2007 Wiley Periodicals, Inc.
Organizing chordates with an organizer
Authors: Garcia‐Fernàndez Jordi , D'Aniello Salvatore , Escrivà Hector
Published: June 2007

Understanding how the chordate body plan originated and evolved is still controversial. The discovery by Spemann and Mangold in 1924 of the vertebrate organizer and its inductive properties in patterning the AP and DV axis was followed by a long gap until the 1960s when scientists started characterizing the molecular events responsible for such inductions. However, the evolutionary origin of the organizer itself remained obscure until very recently; did it appear together with the origin and radiation of vertebrates, or was it a chordate affair? A recent study by Yu and collaborators,1 which analyses the expression of several organizer‐specific genes in amphioxus together with recent phylogenetic data that reversed the position of invertebrate extant chordates (e.g. urochordates and cephalochordates), indicates that the organizer probably appeared in early chordates. It likely had separate signalling centres generating BMP and Wnt signalling gradients along the DV and AP axis. The organizer was then lost in the urochordate lineage, most probably as an adaptation to a rapid and determinate development. BioEssays 29:619–624, 2007. © 2007 Wiley Periodicals, Inc.
Evolution of the cytoskeleton
Authors: Erickson Harold P.
Published: June 2007

The eukaryotic cytoskeleton appears to have evolved from ancestral precursors related to prokaryotic FtsZ and MreB. FtsZ and MreB show 40–50% sequence identity across different bacterial and archaeal species. Here I suggest that this represents the limit of divergence that is consistent with maintaining their functions for cytokinesis and cell shape. Previous analyses have noted that tubulin and actin are highly conserved across eukaryotic species, but so divergent from their prokaryotic relatives as to be hardly recognizable from sequence comparisons. One suggestion for this extreme divergence of tubulin and actin is that it occurred as they evolved very different functions from FtsZ and MreB. I will present new arguments favoring this suggestion, and speculate on pathways. Moreover, the extreme conservation of tubulin and actin across eukaryotic species is not due to an intrinsic lack of variability, but is attributed to their acquisition of elaborate mechanisms for assembly dynamics and their interactions with multiple motor and binding proteins. A new structure‐based sequence alignment identifies amino acids that are conserved from FtsZ to tubulins. The highly conserved amino acids are not those forming the subunit core or protofilament interface, but those involved in binding and hydrolysis of GTP. BioEssays 29:668–677, 2007. © 2007 Wiley Periodicals, Inc.
Possible role of mitochondrial dysfunction in central neurodegeneration of ovariectomized rats
Authors: Shi Chun , Xu Xiao Wu , Forster E. Lucy , Tang Li Feng , Ge ZhenYing , Yew David T. , Xu Jie
Published: June 2007

In the present study, ovariectomized Sparague‐Dawley rats were used to mimic the pathological changes of post‐menopausal females with genistein and estradiol benzoate (EB) as substitutes for endogenous estradiol. Measurements of hippocampal ATP content, mitochondrial ATP content and the rate of mitochondrial ATP synthesis in the hippocampus indicated that after ovariectomy, brain energy metabolism of the rats presented a transient change in hippocampal ATP content which was significant from the 6th to the 8th day after ovariectomy. The change on the 6th day was the most noteworthy. Mitochondrial ATP content and the rate of mitochondrial ATP synthesis of the hippocampus were also lowered. However, after using EB or genistein, the three indicators returned to normal. It is suggested that mitochondrial dysfunction may play a key role in Alzheimer's disease (AD) of the post‐menopausal female, and may serve as the target for endogenous estrogen and exogenous phytoestrogen. In addition, genistein, which possesses the properties of estrogen but not its side effects such as carcinogenicity, could reverse the bioenergetic defects of ovariectomized rats and perhaps be used as a substitute for estradiol to prevent or treat central neurodegeneration in post‐menopausal women. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of the 2,4,5‐Tri‐tert‐butyl‐1,3‐diphospholide Anion by Phosphinidene Elimination from 2,4,6‐Tri‐tert‐butyl‐1,3,5‐triphosphabenzene on Treatment with the Amide Li[NPh(SiMe3)]
Authors: Clendenning Scott B. , Hitchcock Peter B. , Lappert Michael F. , Merle Philippe G. , Nixon John F. , Nyulászi László
Published: June 2007

Treatment of the lithium amide Li[NPh(SiMe3)] with 2,4,6‐tri‐tert‐butyl‐1,3,5‐triphosphabenzene, P3C3tBu3, in a 1:2 ratio afforded equimolar amounts of the lithium salt of the five‐membered 2,4,5‐tri‐tert‐butyl‐1,3‐diphospholide anion, LiP2C3tBu3 (isolated as its N,N,N′,N′‐tetramethylethylenediamine (TMEDA) adduct), and the tricyclic compound 6‐[phenyl(trimethylsilyl)amino]‐3,5,7‐tri‐tert‐butyl‐1,2,4,6‐tetraphosphatricyclo[3.2.0.02,7]hept‐3‐ene. Both compounds have been structurally characterised by single‐crystal X‐ray diffraction studies. The mechanism of this remarkable reaction has been elucidated by theoretical methods at the B3LYP/6‐311+G** level of theory. The reaction involves a hitherto unobserved aminophosphinidene, which was formed by abstraction of a phosphorus atom from triphosphabenzene. The intermediate aminophosphinidene, which is further stabilised by the solvent THF, shows, in agreement with previous theoretical predictions, enhanced stability and reacts then with a second molecule of triphosphabenzene.
Scope and Limitations of Baird's Theory on Triplet State Aromaticity: Application to the Tuning of Singlet–Triplet Energy Gaps in Fulvenes
Authors: Ottosson Henrik , Kilså Kristine , Chajara Khalil , Piqueras Mari Carmen , Crespo Raül , Kato Haruhisa , Muthas Daniel
Published: June 2007

Utilizing Baird's theory on triplet state aromaticity, we show that the singlet–triplet energy gaps (ΔEST) of pentafulvenes are easily varied through substitution by as much as 36 kcal mol−1. This exploits the fact that fulvenes act as aromatic chameleons in which the dipoles reverse on going from the singlet ground state (S0) to the lowest ππ* triplet state (T1); thus, their electron distributions are adapted so as to achieve some aromaticity in both states. The results are based on quantum chemical calculations with the OLYP density functional theory method and the CASPT2 ab initio method, as well as spectroscopic determination of ΔEST by triplet sensitization. The findings can also be generalized to fulvenes other than the pentafulvenes, even though the effect is attenuated as the size of the fulvene increases. Our studies thus reveal that triplet‐state aromaticity can greatly influence the properties of conjugated compounds in the T1 state.
Das Ozonloch und seine Ursachen
Authors: Dameris Martin , Peter Thomas , Schmidt Ulrich , Zellner Reinhard
Published: June 2007

Das Ozon in der Atmosphäre gehört zu dem am längsten und am umfassendsten beobachteten Spurengasen. Das Muster seiner Verteilung über den Globus und mit der Höhe – vom Boden bis in ca. 80 km Höhe – ist gut bekannt. Seine Bedeutung in den verschiedenen Schichten der Atmosphäre ist allerdings sehr unterschiedlich. Während das Ozon in der Troposphäre als Quelle von Photooxidantien (wie dem OH‐Radikal) wirkt und zur Erwärmung des Globus aufgrund seines Treibhauseffektes beiträgt, ist das Ozon in der Stratosphäre hauptsächlich für den Schutz der Biosphäre vor der kurzwelligen Strahlung der Sonne verantwortlich. In beiden Regionen wird das Ozon auch durch unterschiedliche Mechanismen gebildet und verbraucht.

Das Ozon in der Stratosphäre wird durch Photochemie des Sauerstoffs gebildet. In der reinen Sauerstoffatmosphäre stellt sich deshalb eine bestimmte Konzentration ein. Die Gegenwart von anthropogen emittierten Spurengasen wie N2O oder die FCKW hat diese Konzentration aufgrund einer Beschleunigung seiner Abbaureaktionen verringert. Besonders starke Ausprägungen hat diese Ozonabnahme in den Polarregionen im Winter erfahren. Als Ursache wurde neben der reinen Gasphasenchemie die Oberflächenchemie von chlorhaltigen Komponenten an sog. polaren stratosphärischen Wolken (PSCs) identifiziert. Damit wird das jährliche Ausmaß des Ozonverlustes in den Polarregionen auch von den mikrophysikalischen Vorraussetzungen (Temperatur, Geschwindigkeit der Partikelbildung) in der polaren Stratosphäre abhängig. Diese sind im Süden über der Antarktis regelmäßig intensiver als im Norden über der Arktis. Aufgrund der Beschlüsse des Montrealer Protokolls zum Schutz der Ozonschicht sowie dem Verbot der Produktion von FCKW und anderer halogenierter Spurengase wird das Ozonloch in einigen Jahrzehnten wieder verschwunden sein. Die spannende Frage ist allerdings, wie der bevorstehende Klimawandel, der sich mit umgekehrten Vorzeichen – nämlich einer Abkühlung der Luft – auch in der Stratosphäre auswirkt, die Erholung der Ozonschicht beeinflussen bzw. verzögern könnte.
Biosphäre und Atmosphäre: Bedeutung biogener Kohlenwasserstoffe
Authors: Steinbrecher Rainer , Koppmann Ralf
Published: June 2007

Die Biosphäre steuert maßgeblich den Spurenstoffaustausch zwischen Erdoberfläche und Atmosphäre. Biogene flüchtige Verbindungen (BVOC) sind sehr reaktiv und werden in großem Umfang von Wäldern produziert. Deshalb sind BVOC wesentlich an Oxidationsprozessen in der Atmosphäre beteiligt. In den letzten Jahren haben zahlreiche nationale und internationale Forschungsprojekte die Wissenslage stark verbessert, insbesondere zu Oxidationspfaden in der Waldatmosphäre, zur biochemischen Bildung von Isoprenoiden und ihrer genetischen Grundlage sowie zum Spektrum der emittierten Verbindungen und ihrer Kontrolle durch Umgebungsfaktoren. Darüber hinaus wurde in Landschaften erstmals mit hoher räumlicher und zeitlicher Auflösung die Verteilung der biogenen Emissionsquellen analysiert und Variationsmuster abgeleitet. Dazu wurden Geräte und analytische Verfahren sowie Modelle neu entwickelt beziehungsweise weiterentwickelt. Trotz des großen Fortschrittes in den letzten Jahren bestehen große Kenntnislücken, insbesondere in der Emission von Sesquiterpenen und sauerstoffhaltigen VOC durch die Biosphäre. Darüber hinaus ist die Luftchemie im Innern von Wäldern erst in Ansätzen verstanden. Deshalb werden in Zukunft aufregende neue Erkenntnisse über den komplexen reaktiven Kohlenstoffumsatz im Erdsystem zu erwarten sein – insbesondere in der Rückkopplung mit Landnutzungsänderungen und dem Klimasystem der Erde.
Screening of Protease Inhibitors as Antiplasmodial Agents. Part I: Aziridines and Epoxides
Authors: Schulz Franziska , Gelhaus Christoph , Degel Björn , Vicik Radim , Heppner Saskia , Breuning Alexander , Leippe Matthias , Gut Jiri , Rosenthal Philip J. , Schirmeister Tanja
Published: June 2007

A broad protease‐based and cell‐based screening of protease inhibitors yielded the aziridine‐2‐carboxylic acid derivative 2 a and the N‐acylated aziridine‐2,3‐dicarboxylic acid derivatives 32 a and 34 b as the most potent inhibitors of falcipain‐2 and falcipain‐3 (IC50 falcipain‐2: 0.079–5.4 μM, falcipain‐3: 0.25–39.8 μM). As the compounds also display in vitro activity against the P. falciparum parasite in the submicromolar and low micromolar range, these compound classes are leads for new antiplasmodial falcipain inhibitors.
Insurance status and stage of cancer at diagnosis among women with breast cancer
Authors: Halpern Michael T. , Bian John , Ward Elizabeth M. , Schrag Nicole M. , Chen Amy Y.
Published: June 2007

BACKGROUND

Individuals without medical insurance or with limited insurance are less likely than those with broader insurance coverage to receive preventive services and to seek timely medical care. The authors examined the associations of insurance status with stage at diagnosis among women with breast cancer.

METHODS

This study included women age ≥40 years who were diagnosed with invasive breast cancer from 1998 to 2003 and who were reported to the National Cancer Data Base. Multivariable logistic regression analyses were used to examine the associations of insurance status with more advanced‐stage breast cancer at diagnosis while controlling for other patient characteristics.

RESULTS

Among the 533,715 women with breast cancer who were included in the current analysis, the proportions with advanced‐stage (III/IV) cancer at diagnosis ranged from 8% among privately insured patients to 18% among uninsured patients and 19% among Medicaid patients; differences in the proportions of women with advanced‐stage cancer were statistically significant (P < .0001). Regression analyses indicated that, compared with privately insured patients, uninsured patients and Medicaid patients had a greater likelihood of diagnosis at stage II (odds ratio [OR], ∼≈1.5) or at stages III/IV (OR, 2.4) versus stage I (P < .001). Black and Hispanic patients also were significantly more likely than white patients to be diagnosed at a more advanced stage (P < .001).

CONCLUSIONS

The results from this study provided strong evidence that patients without health insurance or with Medicaid coverage, as well as black and Hispanic patients, were more likely to present with advanced‐stage breast cancer. These results are consistent with other reports that have documented less use of preventive services, including mammography, among uninsured women and delays in diagnosis and treatment for black and Hispanic women. Cancer 2007. © 2007 American Cancer Society.
The adequacy of the access‐to‐care debate
Authors: Wender Richard C.
Published: June 2007

The American Cancer Society is calling for a deeper understanding of the meaning of adequate health insurance coverage in our nation's debate about access to care. Ensuring that primary care, prevention, early detection, and quality care are available to all will require health care reform.
The impact of health insurance status on stage at diagnosis of oropharyngeal cancer
Authors: Chen Amy Y. , Schrag Nicole M. , Halpern Michael T. , Ward Elizabeth M.
Published: June 2007

BACKGROUND.

Although patients who have early‐stage oropharyngeal cancer can be treated with little impairment of function, the treatment of advanced disease can result in decreased quality of life and mortality. Patients without insurance and with other barriers to access to care may delay seeking medical attention for early symptoms, resulting in more advanced disease at presentation. In this study, the authors examined whether patients who had no insurance or who were covered by Medicaid insurance were more likely to present with advanced oropharyngeal cancer.

METHODS.

In this retrospective cohort study from the National Cancer Database from 1996 to 2003, patients with known insurance status who were diagnosed with invasive oropharyngeal cancer at Commission on Cancer facilities (n = 40,487) were included. Adjusted and unadjusted logistic regression models were used to analyze the likelihood of presenting with more advanced stage disease.

RESULTS.

After controlling for other sociodemographic characteristics, patients with advanced oropharyngeal cancer at diagnosis were more likely to be uninsured (odds ratio [OR], 1.37; 95% confidence interval [95% CI], 1.21–1.25) or covered by Medicaid (OR, 1.31; 95% CI, 1.19–1.46) compared with patients who had private insurance. Similarly, patients were most likely to present with the largest tumors (T4 disease) if they were uninsured (OR, 2.82; 95% CI, 2.46–3.23) or covered by Medicaid (OR, 2.95; 95% CI, 2.63–3.31). They also were more likely to present with the greatest degree of lymph node involvement (N3) if they were uninsured (OR, 2.06; 95% CI, 1.76–2.40) or covered by Medicaid (OR, 1.66; 95% CI, 1.45–1.90).

CONCLUSIONS.

Individuals who lacked insurance or had Medicaid coverage were at the greatest risk for presenting with advanced oropharyngeal cancer. In the current study, the results for the Medicaid group may have been influenced by the postdiagnostic enrollment of uninsured patients. Insurance coverage appeared to be a highly modifiable predictor of cancer stage. The findings indicated that it is important to consider the impact of insurance coverage on disease stage at diagnosis and associated morbidity, mortality, and quality of life. Cancer 2007. © 2007 American Cancer Society.
Asymptotic behavior of smooth solutions for partially dissipative hyperbolic systems with a convex entropy
Authors: Bianchini Stefano , Hanouzet Bernard , Natalini Roberto
Published: June 2007

We study the asymptotic time behavior of global smooth solutions to general entropy, dissipative, hyperbolic systems of balance laws in m space dimensions, under the Shizuta‐Kawashima condition. We show that these solutions approach a constant equilibrium state in the Lp‐norm at a rate O(t− (m/2)(1 − 1/p)) as t → ∞ for p ∈ [min{m, 2}, ∞]. Moreover, we can show that we can approximate, with a faster order of convergence, the conservative part of the solution in terms of the linearized hyperbolic operator for m ≥ 2, and by a parabolic equation, in the spirit of Chapman‐Enskog expansion in every space dimension. The main tool is given by a detailed analysis of the Green function for the linearized problem. © 2007 Wiley Periodicals, Inc.
Androgen modulates the kinetics of the delayed rectifying K+ current in the electric organ of a weakly electric fish
Authors: McAnelly M. Lynne , Zakon Harold H.
Published: June 2007

Weakly electric fish such as Sternopygus macrurus utilize a unique signal production system, the electric organ (EO), to navigate within their environment and to communicate with conspecifics. The electric organ discharge (EOD) generated by the Sternopygus electric organ is quasi‐sinusoidal and sexually dimorphic; sexually mature males produce long duration EOD pulses at low frequencies, whereas mature females produce short duration EOD pulses at high frequencies. EOD frequency is set by a medullary pacemaker nucleus, while EOD pulse duration is determined by the kinetics of Na+ and K+ currents in the electric organ. The inactivation of the Na+ current and the activation of the delayed rectifying K+ current of the electric organ covary with EOD frequency such that the kinetics of both currents are faster in fish with high (female) EOD frequency than those with low (male) EOD frequencies. Dihydrotestosterone (DHT) implants masculinize the EOD centrally by decreasing frequency at the pacemaker nucleus (PMN). DHT also acts at the electric organ, broadening the EO pulse, which is at least partly due to a slowing of the inactivation kinetics of the Na+ current. Here, we show that chronic DHT treatment also slows the activation and deactivation kinetics of the electric organ's delayed rectifying K+ current. Thus, androgens coregulate the time‐varying kinetics of two distinct ion currents in the EO to shape a sexually dimorphic communication signal. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
Presynaptic plasticity and associative learning are impaired in a Drosophila presenilin null mutant
Authors: Knight David , Iliadi Konstantin , Charlton Milton P. , Atwood Harold L. , Boulianne Gabrielle L.
Published: June 2007

Alzheimer's disease is a neurodegenerative disorder characterized by progressive memory and cognitive decline that is associated with changes in synaptic plasticity and neuronal cell loss. Recent evidence suggests that some of these defects may be due to a loss of normal presenilin activity. Here, we have examined the effect of loss of Drosophila presenilin (psn) function on synaptic plasticity and learning. Basal transmitter release was elevated in psn mutants while both paired pulse synaptic plasticity and post‐tetanic potentiation were impaired. These defects in synaptic strength and plasticity were not due to developmental defects in NMJ morphology. We also found that psn null terminals take up significantly less FM 4‐64 than control terminals when loaded with high frequency stimulation, suggesting a defect in synaptic vesicle availability or mobilization. To determine whether these reductions in synaptic plasticity had any impact on learning, we tested the larvae for defects in associative learning. Using both olfactory and visual learning assays, we found that associative learning is impaired in psn mutants compared with controls. Both the learning and synaptic defects could be rescued by expression of a full length psn transgene suggesting the defects are specifically due to a loss of psn function. Taken together, these results provide the first evidence of learning and synaptic defects in a Drosophila psn mutant and strongly suggest a presynaptic role for presenilin in normal neuronal function. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
Endothelial cell‐matrix interactions determine maturation of dendritic cells
Authors: Methe Heiko , Hess Shmuel , Edelman Elazer R.
Published: June 2007

The fate of allo‐ and xenogeneic endothelial cell (EC) implants is regulated by EC‐matrix interactions. While free EC are destroyed by a vigorous immune reaction, EC embedded within 3D collagen cells are well tolerated. Given the critical role DC serve in immune reactivity, we hypothesized that EC‐driven DC maturation depends on EC‐matrix contact. In marked contrast to DC co‐cultured with a cytokine cocktail or with allo‐ and xenogeneic EC grown to confluence on 2D tissue culture plates, DC exposed to 3D matrix‐embedded allo‐ and xenogeneic EC failed to mature, retaining their endocytic activity and exhibiting significantly reduced expression of maturation markers (costimulatory molecules, HLA‐DR, CD83; p <0.01). Matrix‐embedded EC also limited cytokine‐induced maturation and activity of DC. Incubation with matrix‐embedded EC inhibited DC induction of allogeneic lymphocyte proliferation (p <0.002) and EC cross‐activation (ICAM‐1, VCAM‐1, HLA‐DR, TLR2 and 4; p <0.01). The endothelium in its quiescent state is confluent and substrate adherent. The former ensures secretion of growth inhibitors rather than promoters, and the latter may ensure immune acceptance. We now demonstrate for the first time that interactions of EC with an underlying 3D matrix affect the ability of EC to drive DC maturation.
Protective capacity and epitope specificity of CD8+ T cells responding to lethal West Nile virus infection
Authors: Brien James D. , Uhrlaub Jennifer L. , Nikolich‐Žugich Janko
Published: June 2007

West Nile virus (WNV) is a small, positive‐strand RNA virus belonging to the Flaviviridae genus, which causes lethal encephalitis in a subset of infected birds and mammals. In humans, WNV exhibits pronounced age‐related morbidity and mortality, but the basis of this effect is unclear, and the molecular and cellular parameters of the host‐WNV infection are just beginning to be elucidated. Indeed, numerous mechanisms were implicated in protection in vivo against WNV (IFN‐I and IFN‐γ, antibody, C’, CD8 and CD4 T cells), but the individual importance of each one of these remains unclear. Here, we show that transfer of highly enriched naïve CD8+ T cells protects the majority of alymphoid mice against lethal WNV infection. To substantiate and expand this finding, we defined the peptide specificity of the CD8 response in H‐2b mice and used a panel of identified peptides to map one dominant (NS4b 2248–2256) and several subdominant epitopes. The hierarchy of these epitopes was stably maintained in the memory responses. Most importantly, CTL lines directed against these peptides conferred protection against lethal WNV infection in direct proportion to the epitope immunodominance. These results provide a springboard for future characterization of T cell responses against WNV and demonstrate, for the first time, that CD8 T cells can single‐handedly protect from this disease.
Preparation and Characterization of a Lignin Modified Electrode
Authors: Milczarek Grzegorz
Published: June 2007

Alkali lignin undergoes strong adsorption on polycrystalline gold electrodes. Subsequent oxidation in a sulfuric acid solution leads to a restructured redox‐active polymer that shows features characteristic for surface confined species. Surface coverage of up to 4.40×10−10 mol cm−2 may be obtained depending on the adsorption time or lignin concentration in the adsorption solution. Using Laviron's approach the electron‐transfer rate constant and the transfer coefficient were found to be 8.9 s−1 and 0.35, respectively. The formal potential of the redox couple shifted negatively with pH at a rate of ca. 60 mV/pH unit, suggesting a 2 e/2 H+ reaction. The redox couple was also found to be a good mediator for electrochemical ascorbic acid oxidation in neutral phosphate buffer with ca. 250 mV reduction of the oxidation overpotential.