bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum modeling of thermoelectric performance of strained Si∕Ge∕Si superlattices using the nonequilibrium Green’s function method
Authors: Bulusu A. , Walker D. G.
Published: October 2007

The cross-plane thermoelectric performance of strained Si∕Ge∕Si superlattices is studied from a quantum point of view using the nonequilibrium Green’s function method. Strain causes the germanium well layers to turn into barriers that promote electron tunneling through the barriers. Electron tunneling produces oscillations in the Seebeck coefficient due to shift in subband energies near the Fermi level. Strain-induced energy splitting can increase the power factor by up to four orders of magnitude in germanium-rich substrates. Also, at large doping, strain lowers the subband energies such that thermoelectric performance is independent of layer thickness between 2 and 4nm germanium barrier layers. The results imply that larger barrier layers can be used at high doping without a performance penalty while avoiding problems with interlayer diffusion that are prevalent in films with small thicknesses.
Structurally frustrated polar nanoregions in BaTiO3-based relaxor ferroelectric systems
Authors: Liu Y. , Withers R. L. , Nguyen B. , Elliott K.
Published: October 2007

This letter presents direct electron diffraction evidence that structurally frustrated one-dimensional polar nanoregions arising from anticorrelated displacements of Ti and nearest neighboring O ions are responsible for the relaxation behavior observed in doped BaTiO3 relaxor ferroelectrics, rather than chemical short range ordering. The role of the dopant ions is not to directly induce polar nanoregions but rather to set up random local strain fields preventing homogeneous strain distortion, thereby suppressing transverse correlation from one ⟨001⟩ chain dipole to the next and hence the development of long range ferroelectric order.
Strong effect of weak diffusion on scalar turbulence at large scales
Authors: Chertkov M. , Kolokolov I. , Lebedev V.
Published: October 2007

Passive scalar turbulence forced steadily is characterized by the velocity correlation scale L, injection scale l, and diffusive scale rd. The scales are well separated if the diffusivity is small, rd⪡l,L, and one normally says that effects of diffusion are confined to smaller scales, r⪡rd. However, if the velocity is single scale, one finds that a weak dependence of the scalar correlations on the molecular diffusivity persists to even larger scales, e.g., l⪢r⪢rd (E. Balkovsky et al., Pis'ma Zh. Eksp. Teor. Fiz. 61, 1012 (1995) [JETP Lett. 61, 1049 (1995)]). We consider the case of L⪢l and report a counterintuitive result, namely the emergence of a new range of large scales, L⪢r⪢l2∕rd, where the diffusivity shows a strong effect on scalar correlations.
Highly parallel mix-and-match fabrication of nanopillar arrays integrated in microfluidic channels for long DNA molecule separation
Authors: Shi J. , Fang A. P. , Malaquin L. , Pépin A. , Decanini D. , Viovy J. L. , Chen Y.
Published: October 2007

We report on a mix-and-match method based on a combination of soft UV nanoimprint lithography, contact optical lithography, and reactive-ion-etch techniques, which is applicable for high throughput manufacturing of nanostructure integrated microfluidic devices. We demonstrate the integration of high density and high aspect ratio nanopillars into microfluidic channels as electrophoresis sieving matrices. As a result, λ DNA and T4 DNA can be separated within a few minutes. By changing the pattern design, the device could be used for separation of other types of molecules.
An instrument for environmental control of vapor pressure and temperature for tensile creep and other mechanical property measurements
Authors: Majsztrik P. W. , Bocarsly A. B. , Benziger J. B.
Published: October 2007

An instrument for measuring the creep response of a material maintained under a controlled environment of temperature and vapor pressure is described. The temperature range of the instrument is 20–250°C while the range of vapor pressure is 0–1atm. Data are presented for tests conducted on this instrument with Nafion®, a perfluorinated ionomer developed by DuPont and used as a membrane in polymer exchange membrane fuel cells, over a range of temperature and water vapor pressure. The data are useful for predicting long-term creep behavior of the material in the fuel cell environment as well as providing insight to molecular level interactions in the material as a function of temperature and hydration. Measurements including dynamic and equilibrium strain due to water uptake as well as elastic modulus are described. The main features of the instrument are presented along with experimental methodology and analysis of results. The adaptation of the instrument to other mechanical tests is briefly described.
Coarse grained model of diffusion in entangled bidisperse polymer melts
Authors: Picu R. C. , Rakshit A.
Published: October 2007

Chain diffusion is studied in mixtures of bidisperse linear polymers of same chemical identity by means of simulations. The two subpopulations are moderately to highly entangled, with the shorter chain length NS, fulfilling NS∕Ne⩾5. To this end, a coarse grained model calibrated to reproduce both the structure and dynamics of chains in monodisperse entangled melts is used [A. Rakshit and R. C. Picu, J. Chem. Phys. 125, 164907 (2006)]. Its performance in reproducing chain dynamics in a polydisperse melt is tested by extensively comparing the results with those obtained from an equivalent fine scale representation of the same system (a bead-spring model). The coarse grained model is used further to investigate the scaling of the diffusion coefficient with the length of the two types of chains and its dependence on the respective fractions. The model reproduces many features observed experimentally. For example, the diffusion coefficient of one of the chain types decreases with increasing the length of the other type chains. It is shown that, in this model, this effect is not linked to constraint release. When the matrix chains become sufficiently long, their length does not influence the diffusion coefficient of the short chains anymore. The diffusion coefficient of the short chains scales with their weight fraction in a manner consistent with experimental observations. In mixtures, the dynamics of the short chains is slower and that of the long chains is marginally faster than in their respective monodisperse melts.
Large finite-difference time domain simulations of a left-handed metamaterial lens with wires and resonators
Authors: Schechter R. S. , Chun S. T.
Published: October 2007

We present high-resolution computational results using large three-dimensional finite-difference time domain simulations of flat lenses made of left-handed metamaterial at microwave frequencies. These parallel computer simulations include all the details of the split-ring resonators, wires, and circuit boards that make up the metamaterial. The region of focusing is shown to be ∼0.5λ in radius and ∼−24dB down in power from the source level. The best focusing with the least aberration and the highest power density occurs at the frequency of peak transmission or best impedance match, as opposed to the frequency where the index of refraction n=−1.
The origin of electron injection improvement in organic light-emitting devices with an organic oxide/rubrene electron injection layer
Authors: Cho Kwanghee , Cho Sang Wan , Whang Chung-Nam , Jeong Kwangho , Kang Seong Jun , Yi Yeonjin
Published: October 2007

The electronic structure of tris(8-hydroquinoline) aluminum (Alq3)/rubrene/poly(ethylene glycol) dimethyl ether (PEGDE)/Al interfaces was studied using in situ ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). The UPS and XPS spectra allowed us to evaluate the complete energy level diagrams and to analyze the chemical interactions at the interfaces. When a PEGDE/rubrene double layer was inserted between Al and Alq3, the electron injection barrier height was greatly reduced compared to the interface without PEGDE/rubrene or with a single insertion layer of either PEGDE or rubrene.
Giant magnetocaloric effect in antiferromagnetic ErRu2Si2 compound
Authors: Samanta Tapas , Das I. , Banerjee S.
Published: October 2007

Giant magnetocaloric effect has been observed in ErRu2Si2, which is associated with field-induced metamagnetic transition from antiferromagnetic to ferromagnetic state. The maximum values of magnetic entropy change (−ΔSMmax) and adiabatic temperature change (ΔTadmax) for a field change of 7T are evaluated to be 19.3J∕kgK and 15.9K, respectively, around 5.5K within the temperature range of 4–25K. The value of ΔTadmax is even larger than other potential magnetic refrigerant materials reported in the same temperature range and also comparable to room temperature giant magnetocaloric materials exhibiting first-order magnetic transition from paramagnetic to ferromagnetic state.
Effects of compressive strains on electrical conductivities of a macroscale carbon nanotube block
Authors: Pushparaj Victor L. , Ci Lijie , Sreekala Subbalakshmi , Kumar Ashavani , Kesapragada Sai , Gall Daniel , Nalamasu Omkaram , Pulickel Ajayan M. , Suhr Jonghwan
Published: October 2007

A macroscopic block (∼9mm3) of aligned carbon nanotubes (CNTs) was grown by chemical vapor deposition and its simultaneous electrical conductivity and compressive strain responses were measured parallel and perpendicular to the CNT alignment. The block exhibits elastic moduli of 0.9 and 1.6MPa for compressive strain of <20% in parallel and perpendicular configurations, respectively. The electrical conductivity increases with increasing compressive strain in both configurations. The reversible electrical conductivity and compressive strain responses of block is attributed to elastic bending of CNTs. These excellent properties of CNT block can be used in compressive strain sensing applications.
Low-field positive magnetoresistance near room temperature in three-component perovskite-type artificial superlattices
Authors: Zhao Kun , He Meng , Lu Hui-bin
Published: October 2007

Perovskite-type superlattices consisting of La0.9Sr0.1MnO3, LaAlO3, and SrTiO3 were fabricated on (001) SrNb0.01Ti0.99O3 substrates by laser molecular beam epitaxy. The three-component superlattice exhibited desirable low-field magnetoresistance effects. At a given current bias of 10μA, positive magnetoresistance ratio was enhanced from 2% to 15% and 22% with increasing temperatures from 15 to 300 and 325K at 300Oe, at which a maximum value occurred from the external magnetic field dependence of magnetoresistance. The nature of the enhanced magnetoresistance is discussed in connection to the interfacial effect.
A gene regulatory network in mouse embryonic stem cells
Authors: Zhou Qing , Chipperfield Hiram , Melton Douglas A. , Wong Wing Hung
Published: October 2007

We analyze new and existing expression and transcription factor-binding data to characterize gene regulatory relations in mouse ES cells (ESC). In addition to confirming the key roles of Oct4, Sox2, and Nanog, our analysis identifies several genes, such as Esrrb, Stat3, Tcf7, Sall4, and LRH-1, as statistically significant coregulators. The regulatory interactions among 15 core regulators are used to construct a gene regulatory network in ESC. The network encapsulates extensive cross-regulations among the core regulators, highlights how they may control epigenetic processes, and reveals the surprising roles of nuclear receptors. Our analysis also provides information on the regulation of a large number of putative target genes of the network.
Structure and dynamics of a ribosome-bound nascent chain by NMR spectroscopy
Authors: Hsu Shang-Te Danny , Fucini Paola , Cabrita Lisa D. , Launay Hélène , Dobson Christopher M. , Christodoulou John
Published: October 2007

Protein folding in living cells is inherently coupled to protein synthesis and chain elongation. There is considerable evidence that some nascent chains fold into their native structures in a cotranslational manner before release from the ribosome, but, despite its importance, a detailed description of such a process at the atomic level remains elusive. We show here at a residue-specific level that a nascent protein chain can reach its native tertiary structure on the ribosome. By generating translation-arrested ribosomes in which the newly synthesized polypeptide chain is selectively
13
C/
15
N-labeled, we observe, using ultrafast NMR techniques, a large number of resonances of a ribosome-bound nascent chain complex corresponding to a pair of C-terminally truncated immunoglobulin (Ig) domains. Analysis of these spectra reveals that the nascent chain adopts a structure in which a native-like N-terminal Ig domain is tethered to the ribosome by a largely unfolded and highly flexible C-terminal domain. Selective broadening of resonances for a group of residues that are colocalized in the structure demonstrates that there are specific but transient interactions between the ribosome and the N-terminal region of the folded Ig domain. These findings represent a step toward a detailed structural understanding of the cellular processes of cotranslational folding.
Familial Alzheimer's disease mutations alter the stability of the amyloid β-protein monomer folding nucleus
Authors: Grant Marianne A. , Lazo Noel D. , Lomakin Aleksey , Condron Margaret M. , Arai Hiromi , Yamin Ghiam , Rigby Alan C. , Teplow David B.
Published: October 2007

Amyloid β-protein (Aβ) oligomers may be the proximate neurotoxins in Alzheimer's disease (AD). Recently, to elucidate the oligomerization pathway, we studied Aβ monomer folding and identified a decapeptide segment of Aβ,
21
Ala–
22
Glu–
23
Asp–
24
Val–
25
Gly–
26
Ser–
27
Asn–
28
Lys–
29
Gly–
30
Ala, within which turn formation appears to nucleate monomer folding. The turn is stabilized by hydrophobic interactions between Val-24 and Lys-28 and by long-range electrostatic interactions between Lys-28 and either Glu-22 or Asp-23. We hypothesized that turn destabilization might explain the effects of amino acid substitutions at Glu-22 and Asp-23 that cause familial forms of AD and cerebral amyloid angiopathy. To test this hypothesis, limited proteolysis, mass spectrometry, and solution-state NMR spectroscopy were used here to determine and compare the structure and stability of the Aβ(21–30) turn within wild-type Aβ and seven clinically relevant homologues. In addition, we determined the relative differences in folding free energies (ΔΔ
G
f
) among the mutant peptides. We observed that all of the disease-associated amino acid substitutions at Glu-22 or Asp-23 destabilized the turn and that the magnitude of the destabilization correlated with oligomerization propensity. The Ala21Gly (Flemish) substitution, outside the turn proper (Glu-22–Lys-28), displayed a stability similar to that of the wild-type peptide. The implications of these findings for understanding Aβ monomer folding and disease causation are discussed.
Aquatic organisms as amber inclusions and examples from a modern swamp forest
Authors: Schmidt Alexander R. , Dilcher David L.
Published: October 2007

To find aquatic organisms in tree resin may seem to be highly unlikely, but the fossil record provides numerous amber-preserved limnetic arthropods (e.g., water beetles, water striders, and crustaceans) and microorganisms (e.g., bacteria, algae, ciliates, testate amoebae, and rotifers). Here we explain the frequently discussed process of embedding aquatic organisms in tree resin based on field studies in a Florida swamp forest. Different aquatic arthropods and all major groups of limnetic microorganisms were found embedded in resin that had contact with swamp water. The taphonomy of aquatic organisms differs from that of terrestrial plants and animals that get stuck on resin surfaces and are enclosed by successive resin outflows. Large and highly motile arthropods are predestined for embedding. The number of microbial inclusions is increased when tiny drops of water with aquatic organisms become enclosed in resin while it is flowing in an aquatic environment. Bacteria and fungi may grow inside the resin as long as it has not solidified and therefore become secondarily accumulated. In contact with air, even resin that had initially been flowing into water may solidify and potentially form amber.
MAL decreases the internalization of the aquaporin-2 water channel
Authors: Kamsteeg Erik-Jan , Duffield Amy S. , Konings Irene B. M. , Spencer Joanna , Pagel Philipp , Deen Peter M. T. , Caplan Michael J.
Published: October 2007

Body water homeostasis depends critically on the hormonally regulated trafficking of aquaporin-2 (AQP2) water channels in renal collecting duct epithelial cells. Several types of posttranslational modifications are clearly involved in controlling the distribution of AQP2 between intracellular vesicles and the apical plasma membrane. Little is known, however, about the protein interactions that govern the trafficking of AQP2 between these organelles. MAL is a detergent-resistant membrane-associated protein implicated in apical sorting events. We wondered, therefore, whether MAL plays a role in the regulated trafficking of AQP2 between intracellular vesicles and the apical surface. We find that AQP2 and MAL are coexpressed in epithelial cells of the kidney collecting duct. These two proteins interact, both in the native kidney and when expressed by transfection in cultured cells. The S256-phosphorylated form of AQP2 appears to interact more extensively with MAL than does the water channel protein not phosphorylated at this serine. We find that MAL is not involved in detergent-resistant membrane association or apical delivery of AQP2 in LLC-PK
1
renal epithelial cells. Instead, MAL increases the S256 phosphorylation and apical surface expression of AQP2. Furthermore, internalization experiments show that MAL induces surface expression of AQP2 by attenuating its internalization. Thus, the involvement of MAL in the cell surface retention of apical membrane proteins could play an important role in regulated absorption and secretion in transporting epithelia.
Mammary gland homeostasis employs serotonergic regulation of epithelial tight junctions
Authors: Stull Malinda A. , Pai Vaibhav , Vomachka Archie J. , Marshall Aaron M. , Jacob George A. , Horseman Nelson D.
Published: October 2007

Homeostatic control of volume within the alveolar spaces of the mammary gland has been proposed to involve a feedback system mediated by serotonin signaling. In this article, we describe some of the mechanisms underlying this feedback based on studies of a human normal mammary epithelial cell line (MCF10A) and mouse mammary epithelium. Mammary serotonin was elevated during lactation and after injection of 5-hydroxytryptophan (5-HTP). The genes encoding the serotonin reuptake transporter (SERT) and the type 7 serotonin receptor (5-HT
7
) were expressed in human and mouse mammary epithelial cells, and serotonin caused a concentration-dependent increase of cAMP in MCF10A cells. Mouse and human mammary epithelial cells formed polarized membranes, in which tight junction activity was monitored. Treatment of mammary epithelial membranes with serotonin receptor antagonists increased their transepithelial electrical resistance (TEER). Antagonist and agonist effects on TEER were mediated by receptors on the basolateral face of the membranes. Our results suggest a process in which serotonin accumulates in the interstitial fluid surrounding the mammary secretory epithelium and is detected by 5-HT
7
receptors, whereupon milk secretion is inhibited. One mechanism responsible for this process is serotonin-mediated opening of tight junctions, which dissipates the transepithelial gradients necessary for milk secretion.
Diffusion-controlled metabolism for long-term survival of single isolated microorganisms trapped within ice crystals
Authors: Rohde Robert A. , Price P. Buford
Published: October 2007

Two known habitats for microbial metabolism in ice are surfaces of mineral grains and liquid veins along three-grain boundaries. We propose a third, more general, habitat in which a microbe frozen in ice can metabolize by redox reactions with dissolved small molecules such as CO
2
, O
2
, N
2
, CO, and CH
4
diffusing through the ice lattice. We show that there is an adequate supply of diffusing molecules throughout deep glacial ice to sustain metabolism for >10
5
yr. Using scanning fluorimetry to map proteins (a proxy for cells) and F420 (a proxy for methanogens) in ice cores, we find isolated spikes of fluorescence with intensity consistent with as few as one microbial cell in a volume of 0.16 μl with the protein mapper and in 1.9 μl with the methanogen mapper. With such precise localization, it should be possible to extract single cells for molecular identification.
Myocardin is a bifunctional switch for smooth versus skeletal muscle differentiation
Authors: Long Xiaochun , Creemers Esther E. , Wang Da-Zhi , Olson Eric N. , Miano Joseph M.
Published: October 2007

Skeletal and smooth muscle can mutually transdifferentiate, but little molecular insight exists as to how each muscle program may be subverted to the other. The myogenic basic helix–loop–helix transcription factors MyoD and myogenin (Myog) direct the development of skeletal muscle and are thought to be dominant over the program of smooth muscle cell (SMC) differentiation. Myocardin (Myocd) is a serum response factor (SRF) coactivator that promotes SMC differentiation through transcriptional stimulation of SRF-dependent smooth muscle genes. Here we show by lineage-tracing studies that Myocd is expressed transiently in skeletal muscle progenitor cells of the somite, and a majority of skeletal muscle is derived from Myocd-expressing cell lineages. However, rather than activating skeletal muscle-specific gene expression, Myocd functions as a transcriptional repressor of Myog, inhibiting skeletal muscle differentiation while activating SMC-specific genes. This repressor function of Myocd is complex, involving histone deacetylase 5 silencing of the Myog promoter and Myocd's physical contact with MyoD, which undermines MyoD DNA binding and transcriptional synergy with MEF2. These results reveal a previously unrecognized role for Myocd in repressing the skeletal muscle differentiation program and suggest that this transcriptional coregulator acts as a bifunctional molecular switch for the smooth versus skeletal muscle phenotypes.
The Phosphorylation of Myosin II at the Ser1 and Ser2 Is Critical for Normal Platelet-derived Growth Factor–induced Reorganization of Myosin Filaments
Authors: Komatsu Satoshi , Ikebe Mitsuo
Published: October 2007

Phosphorylation of the regulatory light chain of myosin II (MLC20) at the activation sites promotes both the motor activity and the filament formation of myosin II, thus playing an important role in various cell motile processes. In contrast, the physiological function of phosphorylation of MLC20at the inhibitory sites is unknown. Here we report for the first time the function of the inhibitory site phosphorylation in the cells. We successfully produced the antibodies specifically recognizing the phosphorylation sites of MLC20at Ser1, and the platelet-derived growth factor (PDGF)-induced change in the phosphorylation at the Ser1 was monitored. The phosphorylation of MLC20at the Ser1 significantly increased during the PDGF-induced actin cytoskeletal reorganization. PDGF disassembled the stress fibers, and this was attenuated with the expression of unphosphorylatable MLC20at the Ser1/Ser2 phosphorylation sites. The present results suggest that the down-regulation of myosin II activity achieved by the phosphorylation at the Ser1/Ser2 sites plays an important role in the normal reorganization of actomyosin filaments triggered by PDGF receptor stimulation.
Tau Phosphorylation Sites Work in Concert to Promote Neurotoxicity In Vivo
Authors: Steinhilb Michelle L. , Dias-Santagata Dora , Fulga Tudor A. , Felch Daniel L. , Feany Mel B.
Published: October 2007

Tau is a microtubule binding protein implicated in a number of human neurodegenerative disorders, including Alzheimer's disease. Phosphorylation of serine-proline/threonine-proline sites, targeted by proline-directed kinases, coincides temporally with neurodegeneration in the human diseases. Recently, we demonstrated that this unique group of serines and threonines has a critical role in controlling tau toxicity in a Drosophila model of tauopathy. Here, we use a combination of genetic and biochemical approaches to examine these sites individually and to determine which of them is primarily responsible for controlling tau neurotoxicity. Despite the importance placed on individual phosphoepitopes and their contributions to disease pathogenesis, our results indicate that no single phosphorylation residue plays a dominant role in controlling tau toxicity. These findings suggest that serine-proline/threonine-proline sites cooperate to mediate neurodegeneration in vivo.
Type Iγ PIP Kinase Is a Novel Uropod Component that Regulates Rear Retraction during Neutrophil Chemotaxis
Authors: Lokuta Mary A. , Senetar Melissa A. , Bennin David A. , Nuzzi Paul A. , Chan Keefe T. , Ott Vanessa L. , Huttenlocher Anna
Published: October 2007

Cell polarization is necessary for directed migration and leukocyte recruitment to inflamed tissues. Recent progress has been made in defining the molecular mechanisms that regulate chemoattractant-induced cell polarity during chemotaxis, including the contribution of phosphoinositide 3-kinase (PI3K)-dependent phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] synthesis at the leading edge. However, less is known about the molecular composition of the cell rear and how the uropod functions during cell motility. Here, we demonstrate that phosphatidylinositol phosphate kinase type Iγ (PIPKIγ661), which generates PtdIns(4,5)P2, is enriched in the uropod during chemotaxis of primary neutrophils and differentiated HL-60 cells (dHL-60). Using time-lapse microscopy, we show that enrichment of PIPKIγ661 at the cell rear occurs early upon chemoattractant stimulation and is persistent during chemotaxis. Accordingly, we were able to detect enrichment of PtdIns(4,5)P2at the uropod during chemotaxis. Overexpression of kinase-dead PIPKIγ661 compromised uropod formation and rear retraction similar to inhibition of ROCK signaling, suggesting that PtdIns(4,5)P2synthesis is important to elicit the backness response during chemotaxis. Together, our findings identify a previously unknown function for PIPKIγ661 as a novel component of the backness signal that regulates rear retraction during chemotaxis.
Modified Wendan Decoction Can Attenuate Neurotoxic Action Associated with Alzheimer′s Disease
Authors: Liu Ping , Zhao Lei , Zhang Shu-Ling , Xiang Ji-Zhou
Published: October 2007

We observed the effect of modified Wendan decoction (modified Wen‐Dan‐Tang) on a cellular model of Alzheimer′s disease. Amyloid beta (AΒ) 25–35 segment neurotoxin was employed to induce a PC12 cellular model of Alzheimer′s disease. After modified Wendan decoction was fed to rats, the serum containing medicine was prepared and changes in cell morphology observed. Cell mortality and survival rate was examined by trypan blue stain assay and MTT method and caspase‐3 expression was detected by western blot, while cell apoptosis was examined by flow cytometry. Cell morphology of prepared serum group was better than that of controls, and cell survival rate in prepared serum group was higher than that in control (P < 0.01 or P < 0.05). Cell mortality, caspase‐3 expression and apoptosis rate in prepared serum group were lower than that in control (P < 0.01 or P < 0.05). We conclude that Modified Wendan Decoction can attenuate the neurotoxicity of AΒ 25–35 and rescue neurons via suppressing apoptotic process.
Metabolic Effects of Avocado/Soy Unsaponifiables on Articular Chondrocytes
Authors: Lippiello Louis , Nardo Joseph V. , Harlan Robert , Chiou Tiffany
Published: October 2007

Avocado/soy unsaponifiable (ASU) components are reported to have a chondroprotective effect by virtue of anti‐inflammatory and proanabolic effects on articular chondrocytes. The identity of the active component(s) remains unknown. In general, sterols, the major component of unsaponifiable plant material have been demonstrated to be anti‐inflammatory in vitro and in animal models. These studies were designed to clarify whether the sterol content of ASU preparations were the primary contributors to biological activity in articular chondrocytes. ASU samples were analyzed by high pressure liquid chromatography (HPLC) and GC mass spectrometry. The sterol content was normalized between diverse samples prior to in vitro testing on bovine chondrocytes. Anabolic activity was monitored by uptake of 35‐sulfate into proteoglycans and quantitation of labeled hydroxyproline and proline content after incubation with labeled proline. Anti‐inflammatory activity was assayed by measuring reduction of interleukin‐1 (IL‐1)‐induced synthesis of PGE2 and metalloproteases and release of label from tissue prelabeled with S‐35.All ASU samples exerted a similar time‐dependent up‐regulation of 35‐sulfate uptake in bovine cells reaching a maximum of greater than 100% after 72 h at sterol doses of 1–10 μg/ml. Non‐collagenous protein (NCP) and collagen synthesis were similarly up‐regulated. All ASU were equally effective in dose dependently inhibiting IL‐1‐induced MMP‐3 activity (23–37%), labeled sulfate release (15–23%) and PGE2 synthesis (45–58%). Up‐regulation of glycosaminoglycan and collagen synthesis and reduction of IL‐1 effects in cartilage are consistent with chondroprotective activity. The similarity of activity of ASU from diverse sources when tested at equal sterol levels suggests sterols are important for biologic effects in articular chondrocytes.
Delayed Emergence, Stem Distortion, Stunting, and Foliar Symptoms Associated with Tobacco Rattle Virus and Paratrichodorus Allius in Potatoes Grown in the Pacific Northwest
Authors: Gieck Stacy L. , David Nicholas L. , Hamm Philip B. , Crosslin James M. , Ingham Russell E.
Published: October 2007

This is the first report of stunting, stem distortion, delayed emergence and foliar TRV symptoms on potato in the Pacific Northwest where approximately 50% of the US potato crop is grown. The shift in use from 1,3 dichloropropene to oxamyl may suggest these symptoms will be more frequently observed in the future.

Accepted for publication 19 May 2007. Published 17 September 2007.
Comparative Susceptibility of Plants Native to the Appalachian Range of the United States to Inoculation with Phytophthora ramorum
Authors: Linderman Robert G. , de Sá Patricia B. , Davis E. Anne
Published: October 2007

Phytophthora ramorum, cause of sudden oak death of trees or ramorum blight of other plant species, has an ever-increasing host range. Some geographic regions are considered to be at high risk of becoming infested with the pathogen, possibly causing plant mortality such as seen in native habitats of California and Oregon. One such region is the Appalachian range of the eastern United States, where known susceptible plants occur and climatic characteristics appear favorable for infections by this pathogen. We collected foliage of a range of plant species native to Appalachia in Kentucky during two summer seasons, and the foliage was shipped to Oregon for inoculation with P. ramorum to determine relative susceptibility. Leaves were needle-wounded and inoculated with either mycelium agar plugs or sporangia of a North American (A2 mating type) or European (A1 mating type) isolate. After 14 days incubation at 20°C in moist boxes, lesions caused by either inoculum type or isolate generally were comparable using digital photos and ASSESS software. Some genera, species, and cultivars within species were highly susceptible, while others were moderately susceptible or not susceptible. These results provide a basis for regional surveyors to select target hosts and to generate survey and management practices for nursery and forest areas.

Accepted for publication 24 April 2007. Published 17 September 2007.
Occurrence of Asian Soybean Rust Caused by Phakopsora pachyrhizi in Mississippi
Authors: Li S. , Moore W. F. , Spinks B. L. , Wells B. C. , Sciumbato G. L. , Robinson S. J. , Libous-Bailey L.
Published: October 2007

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi Sydow is one of the most destructive diseases of soybean. The first detection of ASR in Mississippi on soybean was in Adams Co. on 16 November 2004. As of November 2006, ASR was found in Claiborne, George, Issaquena, Jackson, Jefferson, Lee, Warren, Washington, and Yazoo counties in 20 locations.

Accepted for publication 22 May 2007. Published 17 September 2007.
Impact of Soybean Planting Date on Soil Population Density of Macrophomina phaseolina
Authors: Wrather J. A. , Shannon J. G. , Mengistu A.
Published: October 2007

A field experiment was conducted during 2000-2003 near Portageville, MO to determine the affects of soybean planting date on the soil population density of Macrophomina phaseolina. The site was planted to cotton the previous 10 years. The planting dates were mid-April, mid-May, and mid-June during 2000-2003, and the cultivars FFR3975 and Asgrow 3834, maturity group 3, were very susceptible to M. phaseolina. Plots were in the same location each year. Soil samples from the top 15-cm soil layer were collected from plots during May 2000-2004 and analyzed for the population density of M. phaseolina. Planting date did not affect the soil population density of M. phaseolina, but the differences in soil population density among years were significant. These results suggest that soybean producers should not be concerned about planting date directly affecting M. phaseolina soil population densities.

Accepted for publication 22 May 2007. Published 17 September 2007.
Reemergence of Goss's Wilt and Blight of Corn to the Central High Plains
Authors: Jackson Tamra A. , Harveson Robert M. , Vidaver Anne K.
Published: October 2007

Goss's bacterial wilt and blight, also known as leaf freckles and wilt was first identified in Dawson Co. in south central Nebraska in 1969. The disease was soon identified in 54 Nebraska counties and six bordering states. Widespread development of symptoms in NE, WY, and CO early in the 2006 growing season led to submission of more than 50 samples to the UNL Panhandle Research and Extension Center's Plant Disease Diagnostic Clinic in Scottsbluff, NE for analysis. Pathogen identification was made based on a combination of test results.

Accepted for publication 5 April 2007. Published 19 September 2007.
Hosta virus X Detected in Kansas
Authors: Kennelly Megan M. , O'Mara Judith , Pierzynski Joy , Hilbert Bill , Appel Jon
Published: October 2007

Hosta virus X (HVX) is a mechanically-spread Potexvirus that infects several species in the genus Hosta. The virus causes a variety of symptoms including color-streaking, mosaic, distortion, and necrosis, though some infected plants remain symptomless. To our knowledge, these are the first occurrences of HVX in Kansas.

Accepted for publication 16 April 2007. Published 26 September 2007.
Expansion of the Range of Pierce's Disease in Virginia
Authors: Wallingford Anna K. , Tolin Sue A. , Myers Ashley L. , Wolf Tony K. , Smith Alson H. , Pfeiffer Douglas G.
Published: October 2007

Pierce's disease (PD) is a vascular disease of grapes vectored by xylem-feeding sharpshooters and leading to vine decline, yield loss, and vine death. Recent warm winters have increased concerns about PD in Virginia. The authors conducted a survey of 31 Virginia vineyards in 21 counties for X. fastidiosa in late fall, 2006. The survey confirms X. fastidiosa in the northernmost vineyards sampled, and in some of the westernmost vineyards in Virginia. It is likely that all vineyards throughout the sampled area are at risk of PD.

Accepted for publication 23 May 2007. Published 4 October 2007.
China's Financial Fragility and Policy Responses
Authors: Huang Yiping , Yang Yongzheng
Published: October 2007

This article discusses the problems facing China in the wake of the Asian financial crisis. Chinas has so far (September 1998) avoided devaluation of its currency, but growth has slowed down and much more economic reform is needed, especially of the fragile banking system. The article focuses on China's financial fragility and outlines the required policy measures.
Foreign Investment in East Asia: A Survey
Authors: Hill Hal , Athukorala Prema‐chandra
Published: October 2007

This article updates the May 1989 literature survey on foreign direct investment (FDI) in the East Asian region published in this journal. Following an overview of trends of FDI in the 1990s, it focuses on three key issues: the impact of the recent Asian economic crisis on FDI inflow relative to other forms of capital inflows; the link between FDI and trade; and technology transfer and adaptation. It is too early to discern the implications of the crisis for host‐country policies and investment decisions of multinational corporations, but the indications are that FDI will continue to play a pivotal role in economic transformation, and in regional and global economic integration.
Phylogeny of Syllidae (Polychaeta) based on combined molecular analysis of nuclear and mitochondrial genes
Authors: Aguado M. Teresa , Nygren Arne , Siddall Mark E.
Published: October 2007

The phylogeny of Syllidae is assessed in a combined analysis of molecular data from nuclear 18S rDNA and mitochondrial 16S rDNA and cytochrome c oxidase subunit I. In total, 103 terminal taxa are examined: 88 syllids in the four classical subfamilies Eusyllinae, Exogoninae, Syllinae and Autolytinae, as well as 15 outgroup taxa from Phyllodocida and Eunicida. Maximum parsimony analysis of the combined data set indicates that Syllidae, as currently delineated, is monophyletic, though not with very high support values. Astreptosyllis Kudenov & Dorsey, 1982, Streptosyllis Webster & Benedict, 1884 and SyllidesÖrsted, 1845 comprise a monophyletic group well differentiated from the rest of the Syllidae. The subfamilies Autolytinae and Syllinae are monophyletic. Exogoninae is monophyletic, although not well supported, and Eusyllinae is clearly paraphyletic. Results corroborate previous studies about the evolution of reproductive modes in that epigamy is the plesiomorphic condition and schizogamy appeared independently in Autolytinae and Syllinae.

© The Willi Hennig Society 2007.
A first‐generation genetic linkage map of the European flat oyster Ostrea edulis (L.) based on AFLP and microsatellite markers
Authors: Lallias D. , Beaumont A. R. , Haley C. S. , Boudry P. , Heurtebise S. , Lapègue S.
Published: October 2007

This study presents the first genetic linkage map for the European flat oyster Ostrea edulis. Two hundred and forty‐six AFLP and 20 microsatellite markers were genotyped in a three‐generation pedigree comprising two grandparents, two parents and 92 progeny. Chi‐square goodness‐of‐fit tests revealed high segregation distortion, which was significant for 32.8% of markers. Sixteen microsatellites and 235 AFLPs (170 type 1:1 AFLPs and 65 type 3:1 AFLPs) were used to build sex‐specific linkage maps using crimap software. The first parental map (P1) consisted of 104 markers grouped in nine linkage groups, and spanned 471.2 cM with an average spacing of 4.86 cM. The second parental map (P2) consisted of 117 markers grouped in 10 linkage groups (which equals the haploid chromosome number), and covered 450.0 cM with an average spacing of 4.21 cM. The estimated coverage of the genome was 82.4% for the P1 map and 84.2% for the P2 map. Eight linkage groups that were probably homologous between the two parents contained the same microsatellites and 3:1 AFLPs (segregating through both parents). Distorted markers were not randomly distributed across the genome and tended to cluster in a few linkage groups. Sex‐specific differences in recombination rates were evident. This first‐generation genetic linkage map for O. edulis represents a major step towards the mapping of QTL such as resistance to bonamiasis, a parasitosis that has drastically decreased populations of flat oysters since the 1960s.
An SNP in the goat CSN2 promoter region is associated with the absence of β‐casein in milk
Authors: Cosenza G. , Pauciullo A. , Colimoro L. , Mancusi A. , Rando A. , Di Berardino D. , Ramunno L.
Published: October 2007

So far, at least eight alleles in the goat CSN2 locus have been associated with the level of β‐casein expression in milk. Alleles CSN2A, CSN2A1, CSN2B, CSN2C, CSN2D and CSN2E have been associated with normal content (allele effects of about 5 g of β‐casein per litre), whereas the CSN20 and CSN201 alleles have been associated with non‐detectable levels of β‐casein. Most of these alleles have been characterized genetically. Herein, we report the identification of a previously unreported SNP in the goat CSN2 promoter region (AJ011018:g.1311T>C), which is associated with the absence of β‐casein in the milk. Furthermore, we developed a PCR‐based method that allows detection of this mutation.
Genetic diversity within chicken populations from different continents and management histories
Authors: Granevitze Z. , Hillel J. , Chen G. H. , Cuc N. T. K. , Feldman M. , Eding H. , Weigend S.
Published: October 2007

Intra‐population variation was assessed in 1970 chickens from 64 populations using 29 autosomal microsatellites. On average, 95% of the loci were polymorphic across populations. In 1456 (c. 83%) of the 1763 combinations of populations and polymorphic loci, no departure from Hardy–Weinberg equilibrium was observed. On average, there were 11.4 alleles per locus and 3.6 alleles per population across loci. Within populations, the average observed heterozygote frequency was 0.46, with a range between 0.20 and 0.64. Dagu, a Chinese population, and the Red Jungle Fowl (Gallus gallus gallus) had the highest average heterozygote frequencies at 0.64 and 0.63 respectively. An inbred line used as a reference population for comparison showed the lowest average of observed heterozygote frequency (0.05), followed by the European population Hamburger Lackhuhn, whose average observed heterozygote frequency was 0.20. A total of 32 private alleles (alleles detected in only one population) for 20 loci were found in 18 populations. H'mong chickens, a Vietnamese population, carried the largest number of private alleles at five, followed by the Red Jungle Fowl with four private alleles. Genetic diversity within populations was low in the NW European fancy breeds and high in the non‐commercial Asian populations, in agreement with population management history.
Identifying native animals in crossbred populations: the case of the Sardinian goat population
Authors: Sechi T. , Usai M. G. , Miari S. , Mura L. , Casu Sara , Carta A.
Published: October 2007

The aim of this work was to develop a strategy for using a genetic analysis for identifying native animals in regions where local breeds have been crossed with improved breeds and then compare that strategy to the overall morphology and breeding histories of the herds for identifying these animals. The experiment included the Sardinian goat population, which is a crossbred of native animals with the Maltese breed. Whole herds were assigned to Maltese (five herds; 49 animals), crossbred (18 herds; 117 animals) or Sardinian (12 herds; 164 animals) groups. For the genetic analysis, genotypes of 22 microsatellites were determined on 330 animals, and basic measurements of genetic diversity were calculated. Genetic variability in the microsatellites was different in the three groups. High positive FIS showed that inbreeding existed in the subpopulations. The index of genetic differentiation, Nei's standard genetic distance and Reynolds’ genetic distance were calculated and found to be significantly different between the three groups. The Sardinian and Maltese groups were the most distant whereas the crossbred group was closer to the Sardinian group. The proportion of the genome derived from two ancestral populations (native Sardinian and Maltese) was assessed using the structure software. Animals were assigned to three clusters on the basis of native Sardinian thresholds. A good correspondence between the empirical (morphology and breeding histories) and the objective genetic analysis was found. Both approaches indicate the presence of three different subpopulations in the Sardinian goat population.
Prevalence of self‐reported hypersensitivity symptoms following intake of alcoholic drinks
Authors: Linneberg A. , Berg N. D. , Gonzalez‐Quintela A. , Vidal C. , Elberling J.
Published: October 2007

Background
Although hypersensitivity symptoms following alcoholic drink consumption are common in asthmatics, the prevalence of such symptoms in the general population is not known.

Objective
To assess the prevalence of hypersensitivity symptoms following alcoholic drink consumption in an adult Northern European general population and the association of these symptoms with the prevalence of allergic rhinitis (AR) and asthma.

Methods
In 2006, a postal questionnaire was sent to a random sample of 18–69‐year‐olds living in Copenhagen, the capital of Denmark. The response rate was 70.7% (4242/6000).

Results
The prevalence of alcohol‐induced symptoms from the upper airways, lower airways, and skin was 7.6% [95% confidence interval (CI): 6.8–8.4%], 3.2% (95% CI: 2.7–3.8%), and 7.2% (95% CI: 6.4–8.9%), respectively. A total of 13.9% (95% CI: 12.9–15.0%) had ever experienced alcohol‐induced symptoms from at least one of the three regions (upper airways, lower airways, or skin), and 9.9% (95% CI: 9.0–10.8%) had experienced symptoms in the last 12 months. All types of beverages were commonly reported as triggers of hypersensitivity symptoms, red wine being the most common. Alcohol‐induced hypersensitivity symptoms from the upper and lower airways were significantly more prevalent in persons with AR and asthma (odds ratios between 3.0 and 8.1, P‐value <0.001 for all associations).

Conclusions
In this Northern European general population, self‐reported hypersensitivity symptoms following the intake of alcoholic drinks are common. These symptoms were markedly more prevalent in persons with AR and asthma. The underlying mechanisms and the clinical significance of these symptoms remain to be elucidated.
Long‐term prognostic value of B‐type natriuretic peptide in cardiac and non‐cardiac causes of acute dyspnoea
Authors: Christ M. , Thuerlimann A. , Laule K. , Klima T. , Hochholzer W. , Perruchoud A. P. , Mueller C.
Published: October 2007

Background  B‐type natriuretic peptide (BNP) levels significantly predict increased risk of death in heart failure. The predictive role of BNP levels in patients with non‐cardiac causes of acute dyspnoea presenting to the emergency department is not well characterized.

Materials and methods  The B‐type natriuretic peptide for Acute Shortness of Breath EvaLuation (BASEL) study enrolled consecutive patients with acute dyspnoea.

Results  Cumulative mortality was 14·8%, 33·1% and 51·9% in 452 patients (age: 19–97 years; 58% male) within low (< 100 pg mL−1), intermediate (100–500 pg mL−1) and high (> 500 pg mL−1) BNP plasma levels at 18 months of follow‐up. BNP classes (point estimate: 1·55, 95%CI: 1·19–2·03, P = 0·001) in addition to age, increased heart rate and diuretic use emerged as significant predictors for long‐term mortality in multivariable Cox regression analyses. The BNP concentration alone had an area under the receiver operating characteristic curve of 0·71 (95%CI: 0·66–0·76; P < 0·001) for predicting 18 months mortality. BNP plasma levels independently predicted long‐term risk of death in patients with non‐cardiac (point estimate: 1·72, 95%CI: 1·16–2·56; P = 0·007) and with cardiac causes of acute dyspnoea (point estimate: 2·21, 95%CI: 1·34–3·64; P = 0·002).

Conclusions  BNP levels are strong and independent predictors for long‐term mortality in unselected dyspnoeic patients presenting to the emergency department independent from the cause of dyspnoea.