bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineral chemistry, crystallization conditions and magma mixing‐mingling at Orduzu volcano (Malatya), Eastern Anatolia, Turkey
Authors: Önal A.
Published: December 2007

The Middle Miocene Orduzu volcanic suite, which is a part of the widespread Neogene Yamadağ volcanism of Eastern Anatolia, consists of a rhyolitic lava flow, rhyolitic dykes, a trachyandesitic lava flow and basaltic trachyandesitic dykes. Existence of mafic enclaves and globules in some of the volcanic rocks, and microtextures in phenocrysts indicate that magma mingling and mixing between andesitic and basaltic melts played an important role in the evolution of the volcanic suite. Major and trace element characteristics of the volcanic rocks are similar to those formed in convergent margin settings. In particular, incompatible trace element patterns exhibit large depletions in high field strength elements (Nb and Ta) and strong enrichments in both large ion lithofile elements (Ba, Th and U) and light rare earth elements, indicating a strong subduction signature in the source of the volcanic rocks. Furthermore, petrochemical data obtained suggest that parental magmas of rhyolite lava and dykes, and trachyandesite lava and basaltic trachyandesite dykes were derived from subduction‐related enriched lithospheric mantle and metasomatized mantle (± asthenosphere), respectively. A detailed mineralogical study of the volcanic suite shows that plagioclase is the principal phenocryst phase in all of the rock units from the Orduzu volcano. The plagioclase phenocrysts are accompanied by quartz in the rhyolitic lava flows and by two pyroxenes in the trachyandesitic lava flows and basaltic trachyandesitic dykes. Oxide phases in all rocks are magnetite and ilmenite. Calculated crystallization temperatures range from 650°C to 800°C for plagioclase, 745°C–1054°C for biotite, 888°C–915°C for pyroxene and 736°C–841°C for magnetite–ilmenite pairs. Calculated crystallization pressures of pyroxenes vary between 1.24–5.81 kb, and oxygen fugacity range from −14.47 to −12.39. The estimates of magmatic intensive parameters indicate that the initial magma forming the Orduzu volcanic unit began to crystallize in a high‐level magma chamber and then was stored in a shallow reservoir where it underwent intermediate‐mafic mixing. The rhyolitic lava flow and dykes evolved in relatively shallower crustal magma chambers. Copyright © 2007 John Wiley & Sons, Ltd.
Heritability of “small‐world” networks in the brain: A graph theoretical analysis of resting‐state EEG functional connectivity
Authors: Smit Dirk J. A. , Stam Cornelis J. , Posthuma Danielle , Boomsma Dorret I. , de Geus Eco J. C.
Published: December 2007

Recent studies have shown that resting‐state functional networks as studied with fMRI, EEG, and MEG may be so‐called small‐world networks. We investigated to what extent the characteristic features of small‐world networks are genetically determined. To represent functional connectivity between brain areas, we measured resting EEG in 574 twins and their siblings and calculated the synchronization likelihood between each pair of electrodes. We applied a threshold to obtain a binary graph from which we calculated the clustering coefficient C (describing local interconnectedness) and average path length L (describing global interconnectedness) for each individual. Modeling of MZ and DZ twin and sibling resemblance indicated that across various frequency bands 46–89% of the individual differences in C and 37–62% of the individual differences in L are heritable. It is asserted that C, L, and a small‐world organization are viable markers of genetic differences in brain organization. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Effects of acute dehydration on brain morphology in healthy humans
Authors: Kempton Matthew J. , Ettinger Ulrich , Schmechtig Anne , Winter Edward M. , Smith Luke , McMorris Terry , Wilkinson Iain D. , Williams Steven C.R. , Smith Marcus S.
Published: December 2007

Dehydration can affect brain structure which has important implications for human health. In this study, we measured regional changes in brain structure following acute dehydration. Healthy volunteers received a structural MRI scan before and after an intensive 90‐min thermal‐exercise dehydration protocol. We used two techniques to determine changes in brain structure: a manual point counting technique using MEASURE, and a fully automated voxelwise analysis using SIENA. After the exercise regime, participants lost (2.2% ± 0.5%) of their body mass. Using SIENA, we detected expansion of the ventricular system with the largest change occurring in the left lateral ventricle (P = 0.001 corrected for multiple comparisons) but no change in total brain volume (P = 0.13). Using manual point counting, we could not detect any change in ventricular or brain volume, but there was a significant correlation between loss in body mass and third ventricular volume increase (r = 0.79, P = 0.03). These results show ventricular expansion occurs following acute dehydration, and suggest that automated longitudinal voxelwise analysis methods such as SIENA are more sensitive to regional changes in brain volume over time compared with a manual point counting technique. Hum Brain Mapp 2009. © 2007 Wiley‐Liss, Inc.
Differential parametric modulation of self‐relatedness and emotions in different brain regions
Authors: Northoff Georg , Schneider Felix , Rotte Michael , Matthiae Christian , Tempelmann Claus , Wiebking Christina , Bermpohl Felix , Heinzel Alexander , Danos Peter , Heinze Hans‐Jochen , Bogerts Bernhard , Walter Martin , Panksepp Jaak
Published: December 2007

Our sense of self is strongly colored by emotions although at the same time we are well able to distinguish affect and self. Using functional magnetic resonance imaging, we here tested for the differential effects of self‐relatedness and emotion dimensions (valence, intensity) on parametric modulation of neural activity during perception of emotional stimuli. We observed opposite parametric modulation of self‐relatedness and emotion dimensions in the dorsomedial prefrontal cortex and the ventral striatum/nucleus accumbens, whereas neural activity in subcortical regions (tectum, right amygdala, hypothalamus) was modulated by self‐relatedness and emotion dimensions in the same direction. In sum, our results demonstrate that self‐relatedness is closely linked to emotion dimensions of valence and intensity in many lower subcortical brain regions involved in basic emotional systems and, at the same time, distinct from them in higher cortical regions that mediate cognitive processes necessary for becoming aware of one's self, for example self‐consciousness. Hum Brain Mapp, 2009. © 2007 Wiley‐Liss, Inc.
Cell culture–produced hepatitis C virus impairs plasmacytoid dendritic cell function
Authors: Shiina Masaaki , Rehermann Barbara
Published: December 2007

Previous studies suggested a functional impairment of dendritic cells (DCs) in patients with chronic hepatitis C. To investigate whether this effect was mediated by a direct interaction of hepatitis C virus (HCV) with DCs, we studied the effects of infectious cell culture–produced hepatitis C virus (HCVcc) on peripheral blood mononuclear cells (PBMCs),

ex vivo

isolated plasmacytoid, and myeloid DCs and

in vitro

generated monocyte-derived DCs of healthy blood donors. HCVcc inhibited toll-like receptor (TLR)-9 (CpG and herpes simples virus)-mediated interferon alpha (IFN-α) production by peripheral blood mononuclear cells (PBMC) and plasmacytoid DCs. This inhibitory effect was also observed in response to ultraviolet (UV)-inactivated, noninfectious HCVcc, and it was not abrogated by neutralizing antibodies, and thus did not appear to require DC infection. Influenza A virus restored maturation and TLR9-mediated IFN-α production. In contrast to its effect on plasmacytoid DCs, HCVcc did not inhibit TLR3-mediated and TLR4-mediated maturation and interleukin (IL)-12, IL-6, IL-10, interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α) production by myeloid DCs and monocyte-derived DCs. Likewise, HCVcc did neither alter the capacity of myeloid DCs nor monocyte-derived DCs to induce CD4 T cell proliferation. Whereas phagocytosis of apoptotic hepatoma cells resulted in DC maturation, this effect was independent of whether the phagocytosed Huh7.5.1 cells were infected with HCVcc. In contrast to HCVcc, vaccinia virus inhibited maturation and TNF-α expression of myeloid DC as well as maturation and IL-6 and IL-10 production of monocyte-derived DC.

Conclusion:

HCVcc inhibited plasmacytoid DCs but not myeloid-derived and monocytoid-derived DCs via a direct interaction that did not require infection. The response of plasmacytoid DCs to influenza A virus infection was not impaired. (Hepatology 2007.)
Expression of free fatty acid receptor GPR40 in the neurogenic niche of adult monkey hippocampus
Authors: Ma Dexuan , Lu Li , Boneva Nadezhda B. , Warashina Shogo , Kaplamadzhiev Desislav B. , Mori Yoshimi , Nakaya Masa‐aki , Kikuchi Mitsuru , Tonchev Anton B. , Okano Hideyuki , Yamashima Tetsumori
Published: December 2007

Polyunsaturated free fatty acids (PUFAs) are known to play critical roles for the development, maintenance, and function of the brain. Recently, we reported that G‐protein coupled receptor 40 (GPR40), one type of PUFA receptors, is expressed throughout the adult primate central nervous system including the hippocampus. This opens a possibility that PUFA might act as extracellular signaling molecules at the GPR40 receptor to regulate neuronal function. Here we studied protein expression of GPR40 in the neurogenic niche of the adult monkey hippocampus under normal and postischemic conditions. Confocal laser microscope analysis of immunostained sections revealed GPR40 immunoreactivity in neural progenitors, immature neurons, astrocytes and endothelial cells of the subgranular zone (SGZ) of the dentate gyrus (DG); a well‐known neurogenic niche within the adult brain. Immunoblotting analysis showed that the GPR40 protein increased significantly in the second week after global cerebral ischemia as compared with the control. This was compatible with the postischemic increment of GPR40‐positive cells in the SGZ as detected by immunofluorescence imaging. Taken together with our previous findings of the SGZ progenitor cell upregulation after ischemia, the present data suggest that PUFA such as docosahexaenoic acid may act via GPR40 to regulate adult hippocampal neurogenesis in primates. © 2007 Wiley‐Liss, Inc.
Cadherin‐8 and N‐cadherin differentially regulate pre‐ and postsynaptic development of the hippocampal mossy fiber pathway
Authors: Bekirov Iddil H. , Nagy Vanja , Svoronos Alexandra , Huntley George W. , Benson Deanna L.
Published: December 2007

Cells sort into regions and groups in part by their selective surface expression of particular classic cadherins during development. In the nervous system, cadherin‐based sorting can define axon tracts, restrict axonal and dendritic arbors to particular regions or layers, and may encode certain aspects of synapse specificity. The underlying model has been that afferents and their targets hold in common the expression of a particular cadherin, thereby providing a recognition code of homophilic cadherin binding. However, most neurons express multiple cadherins, and it is not clear whether multiple cadherins all act similarly in shaping neural circuitry. Here we asked how two such cadherins, cadherin‐8 and N‐cadherin, influence the guidance and differentiation of hippocampal mossy fibers. Using organotypic hippocampal cultures, we find that cadherin‐8 regulates mossy fiber fasciculation and targeting, but has little effect on CA3 dendrites. In contrast, N‐cadherin regulates mossy fiber fasciculation, but has little impact on axonal growth and targeting. However, N‐cadherin is essential for CA3 dendrite arborization. Both cadherins are required for formation of proper numbers of presynaptic terminals. Mechanistically, such differential actions of these two cadherins could, in theory, reflect coupling to distinct intracellular binding partners. However, we find that both cadherins bind β‐catenin in dentate gyrus (DG). This suggests that cadherins may engage different intracellular signaling cascades downstream of β‐catenin, coopt different extracellular binding partners, or target distinct subcellular domains. Together our findings demonstrate that cadherin‐8 and N‐cadherin are critical for generating the mossy fiber pathway, but that each contributes differentially to afferent and target differentiation, thereby complementing one another in the assembly of a synaptic circuit. © 2007 Wiley‐Liss, Inc.
Skeletal muscle cells express the profibrotic cytokine connective tissue growth factor (CTGF/CCN2), which induces their dedifferentiation
Authors: Vial Cecilia , Zúñiga Lidia Miriam , Cabello‐Verrugio Claudio , Cañón Pablo , Fadic Ricardo , Brandan Enrique
Published: December 2007

Fibrotic disorders are typified by excessive connective tissue and extracellular matrix (ECM) deposition that precludes normal healing processes of different tissues. Connective tissue growth factor (CTGF) seems to be involved in the fibrotic response. Several muscular dystrophies are characterized by a progressive weakness and wasting of the musculature, and by extensive fibrosis. However, the exact role of CTGF in skeletal muscle is unknown. Here we show that myoblasts and myotubes are able to synthesize CTGF in response to transforming growth factor type‐β (TGF‐β) and lysophosphatidic acid (LPA). CTGF induced several ECM constituents such as fibronectin, collagen type I and α4, 5, 6, and β1 integrin subunits in myoblasts and myotubes. CTGF had an important inhibitory effect on muscle differentiation evaluated by the decrease in the nuclear translocation of the early muscle regulatory factor myogenin and myosin. Remarkable, CTGF treatment of myoblasts induced their dedifferentiation, characterized by down regulating MyoD and desmin, two markers of committed myoblasts, together with a strong reorganization of cytoskeletal filaments. These results provide novel evidence for the underlying mechanisms and participation of skeletal muscle cells in the synthesis and role of CTGF inducing fibrosis, inhibiting myogenesis and dedifferentiating myoblasts. J. Cell. Physiol. 215: 410–421, 2008. © 2007 Wiley‐Liss, Inc.
Differential regulation of the lateral mobility of plasma membrane phospholipids by the extracellular matrix and cholesterol
Authors: Ramprasad O.G. , Rangaraj Nandini , Srinivas G. , Thiery Jean Paul , Dufour Sylvie , Pande Gopal
Published: December 2007

In this study, we compared qualitative and quantitative changes in the lateral mobility of phospholipid molecules in the plasma membrane of intact cells under various conditions of specific interaction of integrins in the cell membrane with two extracellular matrix (ECM) components viz. fibronectin (FN) and laminin (LN). We found a strong and specific correlation between the lower lateral mobility of phosphatidylcholine (PC) and higher lateral mobility of phosphatidylethanolamine (PE) when cells were expressing high levels of α5β1 integrin and thus were adherent and motile on FN. The interaction between PC and FN in α5 integrin expressing cells was aided by the strong affinity of α5 integrin to the FN matrix. Cholesterol was involved in regulating the lateral mobility of PC to a great extent and of PE to a lesser extent without affecting the overall microviscosity of the plasma membrane or the distribution of caveolin‐marked domains. The distribution and mobility of PC and PE molecules in the lamellipodial regions differed from that in the rest of the membrane and also in the more motile and in the less motile cells. We propose that these differences in distribution of PC and PE in different regions of cell membrane and their respective lateral mobility are observed due to the specific interaction of PC molecules with FN molecules in the ECM. Our results outline a new role of integrin–matrix interactions in the regulation of membrane phospholipid behavior. J. Cell. Physiol. 215: 550–561, 2008. © 2007 Wiley‐Liss, Inc.
GRP78 and Raf‐1 cooperatively confer resistance to endoplasmic reticulum stress‐induced apoptosis
Authors: Shu Chih‐Wen , Sun Fang‐Chun , Cho Jun‐Hung , Lin Chih‐Chien , Liu Pei‐Feng , Chen Ping‐Yen , Chang Margaret Dah‐Tsyr , Fu Hua‐Wen , Lai Yiu‐Kay
Published: December 2007

The chaperone glucose‐regulated protein, 78/immunoglobulin binding protein (GRP78/Bip), protects cells from cytotoxicity induced by DNA damage or endoplasmic reticulum (ER) stress. In this study, we showed that GRP78 is a major inducible protein in human non‐small cell lung cancer H460 cells treated with ER stress inducers, including A23187 and thapsigargin. AEBSF, an inhibitor of serine protease, diminished GRP78 induction, enhanced mitochondrial permeability, and augmented apoptosis in H460 cells during ER stress. Simultaneously, AEBSF promoted Raf‐1 degradation and suppressed phosphorylation of Raf‐1 at Ser338 and/or Tyr340 during ER stress. Coimmunoprecipitation assays and subcellular fractionations showed that GRP78 associated and colocalized with Raf‐1 on the outer membrane of mitochondria, respectively. While treatment of cells with ER stress inducers inactivated BAD by phosphorylation at Ser75, a Raf‐1 phosphorylation site; AEBSF attenuated phosphorylation of BAD, leading to cytochrome c release from mitochondria. Additionally, overexpression of GRP78 and/or Raf‐1 protected cells from ER stress‐induced apoptosis. Taken together, our results indicate that GRP78 may stabilize Raf‐1 to maintain mitochondrial permeability and thus protect cells from ER stress‐induced apoptosis. J. Cell. Physiol. 215: 627–635, 2008. © 2007 Wiley‐Liss, Inc.
Interleukin‐18 stimulates fibronectin expression in primary human cardiac fibroblasts via PI3K‐Akt‐dependent NF‐κB activation
Authors: Reddy Venkatapuram Seenu , Harskamp Ralf Egan , van Ginkel Margreet Willie , Calhoon John , Baisden Clinton Eugene , Kim In‐San , Valente Anthony J. , Chandrasekar Bysani
Published: December 2007

Fibronectin (FN), a key component of the extracellular matrix, is upregulated in cardiac tissue during myocardial hypertrophy and failure. Here we show that interleukin (IL)‐18, a proinflammatory and pro‐hypertrophic cytokine, stimulates FN expression in adult human cardiac fibroblasts (HCF), an effect blocked by either the IL‐18BP:Fc chimera or IL‐18 neutralizing antibodies. IL‐18 stimulated FN promoter–reporter activity in HCF, a response attenuated by mutation of an NF‐κB binding site in the FN promoter. Overexpression of p65 stimulated FN transcription. IL‐18 stimulated in vitro (p65, p50) and in vivo NF‐κB DNA binding activities, and induced κB‐dependent reporter gene activity. These effects were inhibited by adenoviral transduction of dominant negative (dn) p65 (Ad.dnp65) and dnIKK2 (Ad.dnIKK2). Investigation of signaling intermediates revealed that IL‐18 stimulated PI3 kinase activity (blocked by wortmannin, LY294002, or Ad.dnPI3Kp85), and Akt phosphorylation and kinase activity (blocked by SH‐5 or Ad.dnAkt). Furthermore, targeting MyD88, IRAK1, TRAF6, PI3K, Akt, and NF‐κB by RNA interference or dn expression vectors blunted IL‐18 mediated FN transcription and mRNA expression. Conversely, FN stimulated IL‐18 expression. These data provide the first evidence that IL‐18 and FN stimulate each other's expression in HCF, and suggest a role for IL‐18, FN and their crosstalk in myocardial hypertrophy and remodeling, disease states characterized by enhanced FN expression and fibrosis. J. Cell. Physiol. 215: 697–707, 2008. © 2007 Wiley‐Liss, Inc.
A23187, ionomycin and thapsigargin upregulate mRNA of HIF‐1α via endoplasmic reticulum stress rather than a rise in intracellular calcium
Authors: Werno Christian , Zhou Jie , Brüne Bernhard
Published: December 2007

Hypoxia inducible factor 1 (HIF‐1) coordinates major responses to hypoxia, with the notion that its alpha subunit is degraded under normoxia but stable under hypoxia. Recently, calcium was shown to affect expression of HIF‐1α. While lowering cytosolic calcium accumulates HIF‐1α, a calcium increase by the ionophores A23187 or ionomycin as well as the endoplasmic reticulum (ER) Ca2+‐ATPase inhibitor thapsigargin produced inconsistent results with reports to either increase or decrease HIF‐1α protein. In the human hepatocyte cell line HepG2 only A23187, but neither ionomycin nor thapsigargin, accumulated HIF‐1α protein under normoxia. However, A23187 does so independently of a calcium increase. A23187 not only accumulated HIF‐1α protein but also mRNA of HIF‐1α, with the notion that protein but not mRNA accumulation was attenuated by blocking mitogen‐activated protein kinase (MAPK), suggesting that HIF‐1α protein accumulation is not a direct consequence of its mRNA elevation. Indeed, protein stability determinations implied that A23187 enhanced translation of HIF‐1α. Interestingly, ionomycin and thapsigargin also increased the HIF‐1α mRNA content. Although not increasing the HIF‐1α protein amount under normoxia, both compounds enhanced protein accumulation of HIF‐1α under hypoxia. Taking into account that induction of ER stress by tunicamycin and brefeldin A, without altering intracellular calcium concentrations, also increased HIF‐1α mRNA, suggests that ER stress pathways enhanced transcription of HIF‐1α mRNA. We conclude that ER stress rather than calcium fluctuations increased HIF‐1α mRNA content by established calcium liberating agents, which alone is insufficient for normoxic HIF‐1α accumulation. J. Cell. Physiol. 215: 708–714, 2008. © 2007 Wiley‐Liss, Inc.
Ni+reactions with aminoacetonitrile, a potential prebiological precursor of glycine
Authors: Lamsabhi Al Mokhtar , Mó Otilia , Yáñez Manuel , Guillemin Jean‐Claude , Haldys Violette , Tortajada Jeanine , Salpin Jean‐Yves
Published: December 2007

The gas‐phase reactions between Ni+(2D5/2) and aminoacetonitrile, a molecule of prebiological interest as possible precursor of glycine, have been investigated by means of mass spectrometry techniques. The mass‐analyzed ion kinetic energy (MIKE) spectrum reveals that the adduct ions [NCCH2NH2, Ni+] spontaneously decompose by loosing HCN, H2, and H2CNH, the loss of hydrogen cyanide being clearly dominant. The structures and bonding characteristics of the aminoacetonitrile–Ni+complexes as well as the different stationary points of the corresponding potential energy surface (PES) have been theoretically studied by density functional theory (DFT) calculations carried out at B3LYP/6‐311G(d,p) level. A cyclic intermediate, in which Ni+is bisligated to the cyano and the amino group, plays an important role in the unimolecular reactivity of these ions, because it is the precursor for the observed losses of HCN and H2CNH. In all mechanisms associated with the loss of H2, the metal acts as hydrogen carrier favoring the formation of the H2molecule. The estimated bond dissociation energy of aminoacetonitrile–Ni+complexes (291 kJ mol−1) is larger than those measured for other nitrogen bases such as pyridine or pyrimidine and only slightly smaller than that of adenine. Copyright © 2007 John Wiley & Sons, Ltd.
Bilateral changes in neuronal activity of the basal ganglia in the unilateral 6‐hydroxydopamine rat model
Authors: Breit S. , Martin A. , Lessmann L. , Cerkez D. , Gasser T. , Schulz J.B.
Published: December 2007

The functional significance of the interhemispheric projections on the basal ganglia level is poorly understood. Insofar as the anatomical evidence for crossing projections between basal ganglia nuclei is sparse, whereas tracing studies demonstrated important crossing projections from the pedunculopontine nucleus (PPN) to the basal ganglia, it is suggested that the PPN might play a key role in interhemispheric regulation of basal ganglia activity. The present study was performed to assess changes in neuronal activity of ipsilateral and contralateral subthalamic nucleus (STN), substantia nigra pars reticulata (SNr), and PPN in the unilateral 6‐hydroxydopamine (6‐OHDA) rat model of advanced PD under urethane anesthesia. After unilateral lesioning of the SNc, the firing rate of contralateral STN neurons significantly increased from 10.9 ± 1.0 spikes/sec (mean ± SEM) to 16.3 ± 1.5 spikes/sec. Similarly, the firing rate of contralateral SNr neurons significantly increased from 19.4 ± 1.2 to 25.7 ± 1.9 spikes/sec, and the firing rate of contralateral PPN neurons significantly increased from 10.6 ± 0.8 to 13.9 ± 1.1 spikes/sec. The observed activity changes in contralateral STN, SNr, and PPN are similar to those induced in the corresponding nuclei of the hemisphere ipsilateral to the nigrostriatal degeneration. Based on previous, predominantly anatomical data, the results of the present study suggest that the PPN on the lesioned side is at the origin of changes in the activity of STN and SNr on the contralateral hemisphere, because of its crossing efferent projections. © 2007 Wiley‐Liss, Inc.
Molecular basis for detection of invading pathogens in the brain
Authors: Falsig Jeppe , van Beek Johan , Hermann Corinna , Leist Marcel
Published: December 2007

Classical immunology textbooks have described the central nervous system as an immune‐privileged site, i.e., as devoid of inflammatory and host‐vs.‐graft immunoreactions. This view has been refined, since we now know that hematopoietic cells infiltrate the CNS under certain circumstances and that CNS‐resident cells are capable of launching an innate immune response. Microglia cells express an extensive repertoire of pattern‐recognition receptors and act as sentinels surveilling the CNS for possible damage or infection. Astrocytes are the most abundant cell type in the brain, and they are capable of launching a strong supportive innate immune response. Novel findings show that both astrocytes and, surprisingly, even neurons express pattern‐recognition receptors. Activation of these receptors leads to a functional response, indicating that cells other than microglia are capable of initiating a primary innate immune response against CNS‐invading pathogens. Here, we put these findings into context with what has been learned from recent in vitro and in vivo experiments about the initiation of an innate immune response in the brain. © 2007 Wiley‐Liss, Inc.
The interrelationship between the cultivation of crops and soil‐strength dynamics
Authors: Stock Oliver , Bens Oliver , Hüttl Reinhard F.
Published: December 2007

It is well accepted that the penetration resistance of soils is, among others factors, highly sensitive to the moisture status of the soil. This study tested the hypothesis of whether the dewatering of a soil by crops of varying dewatering capacities significantly affects the soil's penetration resistance and whether this contributes to an exceedance of the commonly accepted root‐growth threshold already in the range of plant‐available water. During a 22‐month period between March 2002 and December 2003, the soil water content of a former lignite strip mine in E Germany was studied. The soil had been restored with Saalian glacial till. Plots contained two different crops, a 3 y–old stand of lucerne (Medicago sativa L.) and a 7 y–old stand of wild rye (Secale multicaule L.). Soil water contents under the two crops were converted on the basis of the water‐retention characteristics into water tensions, allowing an investigation of the changes in the measured water content in the wider context of the water availability to the crops. During both growing seasons, the water tension under lucerne exceeded the permanent‐wilting point (104.2 hPa) for up to 20 weeks between 0 and 90 cm, which is equal to a predicted penetration resistance of >15 MPa. Water tensions under the wild rye rose only up to a maximum of 103 hPa for the same period, so that the predicted penetration‐resistance values remained constantly <5 MPa. Our findings demonstrate that the dewatering by plants during the growing seasons affects the actual strength of the soil, which can lead to the exceeding of the commonly accepted root‐growth threshold.
Compost and P amendments for stimulating microorganisms and maize growth in a saline soil from Pakistan in comparison with a nonsaline soil from Germany
Authors: Muhammad Sher , Müller Torsten , Joergensen Rainer Georg
Published: December 2007

A 92 d greenhouse pot experiment with maize (Zea mays L.) was carried out with a strongly saline soil from Pakistan (P‐s) in comparison with a nonsaline soil from Germany (G‐s) similar in pH and texture. The aim was to evaluate salinity effects on the decomposition of compost and effects of compost and P amendments on (1) plant growth and (2) microbial‐biomass formation. The yield of maize shoot‐C and root‐C increased in both soils in the order nonamended control < +triple superphosphate (TSP) (A1) < +compost (A2) < +(compost + TSP) (A3) < +TSP‐enriched compost (A4). In comparison with the control, the highest yield in treatment A4 was nearly doubled on the G‐s, but was increased more than 8‐fold on the saline P‐s. Averaging the three compost treatments, 32% of the compost added was decomposed in the German soil and 36% in the Pakistani soil on the basis of the compost recovered as particulate organic matter. These data were roughly in agreement with the CO2‐evolution data. This indicates that the decomposition of compost was not affected by salinity. Compost‐derived CO2 was mainly evolved until day 32, the root‐derived CO2 from day 74 until the end of the experiment. The addition of compost resulted in higher contents of microbial biomass C and biomass P, but also in that of NaHCO3‐extractable P. These three properties were significantly interrelated (r = 0.64–0.85), but on a lower level of significance than the relationships between shoot‐C, root‐C, and NaHCO3‐extractable P (r = 0.90–0.93). Applying compost enriched with TSP (incubation of compost and TSP for 24 h) provided considerably more P to plants and microorganisms than the separate addition of these two components. The results suggest that the role of the microbial biomass as a sink and source for available P deserves further attention.
Seasonal effect of the exotic invasive plant Solidago gigantea on soil pH and P fractions
Authors: Herr Cécile , Chapuis‐Lardy Lydie , Dassonville Nicolas , Vanderhoeven Sonia , Meerts Pierre
Published: December 2007

Invasions by alien plants can alter biogeochemical cycles in recipient ecosystems. We test if Early Goldenrod (Solidago gigantea) alters P fractions. To that end, we compare invaded plots and adjacent, uninvaded resident vegetation for specific fractions of organic and inorganic P, phosphomonoesterase (PME) activity in topsoil, and immobilization of P in above‐ and belowground organs and in soil microbial biomass. Invaded plots had lower soil pH and 20%–30% higher labile P fractions (resin‐Pi, bicarb‐Pi, NaOH‐Pi), and the difference was consistent across seasons. There was no difference in microbial P. Alkaline‐PME activity was 30% lower in topsoil of invaded plots. Annual P uptake in aboveground phytomass was not markedly higher in Solidago. In contrast, P in belowground organs steadily increased in autumn in invaded plots, due to both increased biomass and increased P concentrations. This indicated higher net P immobilization in Solidago, far in excess of both resorption from senescing shoots and P requirements for aboveground biomass in subsequent year. Higher turnover rates of P in belowground organs and mobilization of sparingly soluble P forms through rhizosphere acidification may be involved in the observed differences in soil P status between invaded and uninvaded plots.
Uptake and apoplastic retention of EDTA‐ and phytosiderophore‐chelated chromium(III) in maize
Authors: Erenoglu Bülent E. , Patra Hemanta K. , Khodr Hicham , Römheld Volker , von Wirén Nicolaus
Published: December 2007

Increasing the mobilization and root uptake of chromium (Cr) by synthetic and plant‐borne chelators might be relevant for the design of phytoremediation strategies on Cr‐contaminated sites. Short‐term uptake studies in maize roots supplied with 51CrCl3 or 51Cr(III)‐EDTA led to higher apoplastic Cr contents in plant roots supplied with 51CrCl3 and in Fe‐sufficient plants relative to Fe‐deficient plants, indicating that Fe stimulated co‐precipitation of Cr. Concentration‐dependent retention of Cr in a methanol:chloroform‐treated cell‐wall fraction was still saturable and in agreement with the predicted tendency of Cr(III) to precipitate as Cr(OH)3. To investigate a possible stimulation of Cr(III) uptake by phytosiderophores, Fe‐deficient maize roots were exposed for 6 d to Cr(III)‐EDTA or Cr(III)‐DMA (2'‐deoxymugineic acid). Relative to plants without Cr supply, the supply of both chelated Cr species in a subtoxic concentration of 1 µM resulted in alleviation of Fe deficiency–induced chlorosis and higher Cr accumulation. Long‐term Cr accumulation from Cr(III)‐DMA was similar to that from Cr(III)‐EDTA, and Cr uptake from both chelates was not altered in the maize mutant ys1, which is defective in metal‐phytosiderophore uptake. We therefore conclude that phytosiderophores increase Cr solubility similar to synthetic chelators like EDTA, but do not additionally contribute to Cr(III) uptake from Cr‐contaminated sites.
Correcting molybdenum deficiency of chickpea in the High Barind Tract of Bangladesh
Authors: Johansen Chris , Musa Abu M. , Kumar Rao J. V. D. K. , Harris David , Yusuf Ali M. , Shahidullah A. K. M. , Lauren Julie G.
Published: December 2007

A major limitation to chickpea grown on residual soil moisture after the harvest of rice in the High Barind Tract (HBT) of Bangladesh is acidic surface soil. A diagnostic trial conducted in the 2001/02 season showed that Mo was limiting growth and yield of chickpea. Multilocational on‐farm trials in the 2002/03 season established that Mo applied to the soil at 500 g ha–1 improved nodulation and plant growth and resulted in grain‐yield responses of 58%–173%. In addition, we tested an application method suitable for resource‐poor farmers where Mo and Rhizobium were added in the seed‐priming process. Multilocational trials in farmers' fields in 2003/04 confirmed that this was as effective as soil application of Mo, giving yield responses of 37%–90%. In each of 2004/05 and 2005/06 seasons, 50 farmers implemented on‐farm evaluations of adding Mo + Rhizobium in the priming solution in operational scale plots (666 m2) across the HBT. Mean responses of up to 50%, compared to priming in water only, were obtained. These results suggest that the severe N deficiency of chickpea commonly observed in the HBT can be effectively alleviated by applying Mo and Rhizobium inoculum through a simple low‐cost technology within the scope of resource‐poor farmers.
Level of trace elements in Pteridophytes growing on serpentine and metalliferous soils
Authors: Cornara Laura , Roccotiello Enrica , Minganti Vincenzo , Drava Giuliana , De Pellegrini Rodolfo , Giorgio Mariotti Mauro
Published: December 2007

A screening of Pteridophytes growing on serpentine and metalliferous soils in Northern Italy was carried out to assess the ability of these plants to tolerate or accumulate trace elements of toxicological interest. Few data are available on metal tolerance/accumulation of terrestrial ferns growing in the Mediterranean region, and several species presented here have never been investigated for this purpose. The trace‐element composition (As, Cd, Cr, Cu, Fe, Ni, Pb, Zn) and P content of aerial parts of plants (12 fern and 2 horsetail species) and of their associated soils were measured. An analysis of the relationship between element concentrations in soil and in shoot revealed a significant correlation only for Zn (p < 0.05). Hierarchical cluster analysis based on element concentrations in plant aerial parts showed two outliers, viz. Equisetum ramosissimum Desf., showing the highest levels of Cr, Fe, Cu, Ni, and As, and Nephrolepis cordifolia C. Presl., showing the highest Pb value. The bioaccumulation factor exceeded 1 only for Cd in two species, Athyrium filix‐femina and Dryopteris filix‐mas. However, also in these cases the corresponding values of the metal in the shoots were below the thresholds for hyperaccumulators. The examined Pteridophytes seem to have developed their adaptation prevalently through mechanisms of tolerance based on metal exclusion. None of these plant species seem suitable for phytoextraction, but N. cordifolia, Pteridium aquilinum ssp. aquilinum, and E. ramosissimum have potential to be used for stabilization and restoration of soils rich in heavy metals.
Dynamic fuzzy wavelet neuroemulator for non‐linear control of irregular building structures
Authors: Jiang Xiaomo , Adeli Hojjat
Published: December 2007

A new non‐linear control model is presented for active control of three‐dimensional (3D) building structures. Both geometrical and material non‐linearities are included in the structural control formulation. A dynamic fuzzy wavelet neuroemulator is presented for predicting the structural response in future time steps. Two dynamic coupling actions are taken into account simultaneously in the control model: (a) coupling between lateral and torsional motions of the structure and (b) coupling between the actuator and the structure. The new neuroemulator is validated using two irregular 3D steel building structures, a 12‐story structure with vertical setbacks and an 8‐story structure with plan irregularity. Numerical validations in both time and frequency domains demonstrate that the new neuroemulator provides accurate prediction of structural displacement responses, which is required in neural network models for active control of structures. In the companion paper, a floating‐point genetic algorithm is presented for finding the optimal control forces needed for active non‐linear control of building structures using the dynamic fuzzy wavelet neuroemulator presented in this paper. Copyright © 2007 John Wiley & Sons, Ltd.
PEDOT‐PSS/singlewall carbon nanotubes composites
Authors: Ham Hyeong Taek , Choi Yeong Suk , Chee Mu Guen , Cha Myoung Hwan , Chung In Jae
Published: December 2007

Poly(3,4‐ethylenedioxythiophene)‐single wall carbon nanotube (SWNT) composites were prepared via coating methods for improving electrical conductivity and flexibility, minimizing loss of transparency. Three types of surface modified SWNTs were prepared through different modification methods: carboxylated SWNT treated with nitric acid to form carboxylic acid group on their surfaces, 1‐pyrenebutyric acid wrapped SWNT, and 1‐pyrenebutyric acid, lithium salt wrapped SWNT. The surface modifiers had influence on the dispersion states of the SWNTs in 2‐propanol. The dispersion states had influence of aggregate concentrations of surface modified SWNTs in polymer matrix, showing lower aggregate concentration for the carboxylated SWNT than those of the other surface modified SWNTs. The dispersion behaviors of SWNTs were also related with transparency and electrical resistance, and flexibility of composite films. Based on the layer‐by‐layer coating method, SWNT composite film properties such as thickness, transparency, and electrical conductivity could be controlled and would be a good example for improving contradictory properties. POLYM. ENG. SCI., 48:1–10, 2008. © 2007 Society of Plastics Engineers
The effect of recycling on LDPE foamability: Elongational rheology
Authors: Kabamba Eddy Twite , Rodrigue Denis
Published: December 2007

The purpose of this work was to investigate changes in the elongational rheology of low density polyethylene (LDPE) when recycled. Both foamed and unfoamed LDPE were submitted up to 10 generations in a closed loop using constant extrusion conditions and azodicarbonamide as a chemical blowing agent. For both foamed and unfoamed polymers, decreasing elongational properties in terms of strain hardening was observed, indicating progressive loss of foamability with the number of time the polymer is recycled. It was also found that the elongational properties of the foamed polymer decreased more rapidly than its unfoamed counterpart. It is believed that higher mechanical degradation of polymer may be the result of higher deformation rates (biaxial) associated with foaming and the accumulation of blowing agent residues limiting polymer chain mobility and entanglement. POLYM. ENG. SCI., 48:11–18, 2008. © 2007 Society of Plastics Engineers
Local residence time, residence revolution, and residence volume distributions in twin‐screw extruders
Authors: Zhang Xian‐Ming , Feng Lian‐Fang , Hoppe Sandrine , Hu Guo‐Hua
Published: December 2007

This work was aimed at studying the overall, partial, and local residence time distributions (RTD); overall, partial and local residence revolution distributions (RRD) and overall, partial and local residence volume distributions (RVD) in a co‐rotating twin screw extruder, on the one hand; and establishing the relationships among them, on the other hand. Emphasis was placed on the effects of the type and geometry of mixing elements (a gear block and various types of kneading elements differing in staggering angle) and process parameters on the RTD, RRD and RVD. The overall and partial RTD were directly measured in‐line during the extrusion process and the local ones were calculated by deconvolution based on a statistical theory. The local RTD allowed comparing the mixing performance of mixing elements. Also it was confirmed both experimentally and theoretically that specific throughput, defined as a ratio of throughput (Q) over screw speed (N), controlled all the above three types of residence distributions, be they local, partial or overall. The RRD and RVD do not provide more information on an extrusion process than the corresponding RTD. Rather they are different ways of representing the same phenomena. POLYM. ENG. SCI., 48:19–28, 2008. © 2007 Society of Plastics Engineers
Temperature, conversion, and phase separation profiles during mold cure of a modified vinyl‐ester resin
Authors: Schroeder Walter F. , Auad María L. , Soulé Ezequiel R.
Published: December 2007

In this work, morphological differences over the thickness of modified vinyl‐ester (VE) samples are studied. A thermodynamic analysis based in the Flory–Rehner theory is proposed to evaluate the spinodal decomposition temperature evolution during the reaction. This model takes into account changes in (styrene‐co‐VE) copolymer composition and binary interaction parameters with conversion. Then, from the energy and mass balance equations, temperature and conversion profiles over the thickness as a function of reaction time are calculated. Combining these profiles with the proposed thermodynamic model, spinodal decomposition conversion graphs are constructed. To verify model predictions, a synthesized VE resin was modified with 7.5 wt% of poly(butadiene‐co‐acrylonitrile) vinyl terminated (VTBN) elastomer and then cured in molds of 3, 7, 12, and 20 mm thickness at 80°C. Fracture surfaces were observed by scanning electron microscopy showing morphological differences over thickness, which can be explained from the results obtained from the simulation. POLYM. ENG. SCI., 48:52–61, 2008. © 2007 Society of Plastics Engineers
Reinforcement of polydimethylsiloxane through formation of inorganic–organic hybrid network
Authors: Jia Liya , Du Zhongjie , Zhang Chen , Li Congju , Li Hangquan
Published: December 2007

Crude silica was modified with silsisquioxane (SSO), which was originated from vinyltriethoxysilane, leading to modified silica. The modified silica with vinyl groups was employed to reinforce polydimethylsiloxane (PDMS) through participating in the hydrosilation reaction. Inorganic–organic hybrid network was formed to obtain higher mechanical properties. Fourier transformation infrared spectroscopy (FTIR) confirmed that the vinyl groups were bonded to the surface of silica. Transmission electron microscopy (TEM) showed that the diameter of the modified silica increased and the shape became irregular. The effects of the amount of SSO, the loading of modified silica, and the vinyl/hydrogen mole ratio on the mechanical properties of the cured PDMS system were investigated. It was found that 40 parts of SSO could result in a sufficient surface modification of the silica. The tensile strength and the modulus (reflected by the stress at 100% elongation) kept increasing with increasing loading of silica. When the vinyl/hydrogen mole ratio was 1:1, the most effective reinforcement was obtained. POLYM. ENG. SCI., 48:74–79, 2008. © 2007 Society of Plastics Engineers
Prediction of the influence of flow‐enhanced crystallization on the dynamics of fiber spinning
Authors: Kohler William H. , McHugh Anthony J.
Published: December 2007

A linearized sensitivity and stability analysis of fiber spinning of semi‐crystalline polymers has been carried out for both low‐ and high‐speed spinning conditions to investigate the relative roles of flow‐enhanced crystallization (FEC) and thermal‐induced crystallization (TIC) on the process dynamics. The analysis is based on an earlier‐developed two‐phase constitutive model for FEC that utilizes either the Giesekus or the Extended Pom‐Pom constitutive equations for the amorphous phase and a rigid‐rod model for the semi‐crystalline phase, combined with the transport balances for the 1‐D fiber spinning model. Model parameters from fits of the steady‐state low‐ and high‐speed spinning of Nylon and L‐polylactic acid are used to illustrate the effects of changes in various process variables (principally air cooling rate and temperature) on the system sensitivity. Results show that higher crystallization, whether from TIC or FEC, generally equates to lower spinline sensitivity. However, factors such as high‐speed necking induced by FEC, viscoelastic stresses, and thermal transport properties are also shown to impact trends in the sensitivity. Because of the specific nature of the FEC model and lack of a general theory for determining model parameters from first principles, calculations and conclusions are necessarily system specific. POLYM. ENG. SCI., 48:88–96, 2008. © 2007 Society of Plastics Engineers
Prediction of molecular weight scale and molecular weight distribution of cellulose using a rheology‐based method
Authors: Zhang Huiru , Tong Mingwei , Li Rongxian
Published: December 2007

Prediction of MW scale and MWD of cellulose by means of a rheology‐based method is developed. In this method, for the cellulose/NMMO·H2O solution, it is assumed that the cellulose MW values calculated by the Rouse terminal relaxation time can be regarded as the peak MW on the MWD curves of cellulose. Consequently, it is realized that the reciprocal of the frequency is converted to the MW scale, obtaining MWD scale curves of cellulose. Meanwhile, the obtained results are compared with those measured by the GPC method. The comparison shows that the calculated peak MW values are approximately equal, the calculated PDI values and MWD curves have the same trends. Consequently, it may be feasible to compare the MW scale and MWD of cellulose by using the rheology‐based method. In addition, the rheology‐based method is simple and fast. Therefore, it is a useful and easy way to analyze the MW scale and MWD of cellulose in the fiber industry. POLYM. ENG. SCI., 48:102–106, 2008. © 2007 Society of Plastics Engineers