bluuebunny/crossref_metadata_2025 huggingface dataset:
A photoelectron spectroscopy study of tunable charge injection barrier between metal/organic interface
Authors: Xu Zheng , Li Sheng-han , Ma Liping , Li Gang , Yang Guanwen , Yang Yang
Published: July 2008

Photoelectron spectroscopy has been used to investigate a tunable charge injection barrier at the metal/organic interface. Results in this study show that the morphology of the Al electrode in the indium tin oxide (ITO)∕LiF∕Al/pentacene structure plays a critical role. When the sample is biased across ITO and Al electrodes, shifts in the binding energies of certain core-level electrons are observed on the surface of the discontinuous thin Al electrode. In contrast, no such shifts are observed on the thick Al electrode. Further studies indicate that applying a voltage bias changes the energy alignment between the discontinuous thin Al electrode and the pentacene layer deposited on it.
Influence of Si∕Fe ratio in multilayer structures on crystalline growth of β-FeSi2 thin film on Si substrate
Authors: Liu Zhengxin , Tanaka Miyoko , Kuroda Ryo , Osamura Masato , Makita Yunosuke
Published: July 2008

The deposited Si∕Fe ratio has been found to have a significant influence on crystalline growth of β-FeSi2 film on Si substrate. Stoichiometry is always satisfied by interdiffusion of Si, under both Si-lean and Si-rich conditions. However, Si diffusion from the substrate into the deposited layer, which compensates for deficient Si, induces an undulated interface, as well as Fe and Si vacancies. On the other hand, excess Si is driven to the β-FeSi2∕Si interface, which results in a lamellar structure with a large number of small grains. Fe and Si vacancies are significantly reduced by excess Si. These results suggest that precise control of the Si∕Fe ratio is essential for good crystallinity and fewer vacancies.
Manipulating optical rotation in extraordinary transmission by hybrid plasmonic excitations
Authors: Li Tao , Liu Hui , Wang Shu-Ming , Yin Xiao-Gang , Wang Fu-Ming , Zhu Shi-Ning , Zhang Xiang
Published: July 2008

Polarized optical transmission properties through the L-shaped holes array in silver film was investigated at near infrared wavelength. Besides the enhanced transmission due to the combined plasmonic excitations, strong optical rotation was definitely observed at specific polarized incidences. After elaborate analyses, two eigenmodes were clearly characterized as the results of the hybrid localized plasmon resonances. Any polarization states from the incidences will degenerate into these two eigenstates after transmissions, suggesting a practical method to manipulate the polarization of light. Our result demonstrates the giant rotation rate achieved by the nanothin sample, indicating potential applications in the micro-optical devices.
Transistor laser with emission wavelength at 1544nm
Authors: Dixon F. , Feng M. , Holonyak N. , Huang Yong , Zhang X. B. , Ryou J. H. , Dupuis R. D.
Published: July 2008

Data are presented demonstrating continuous wave laser operation at −185°C of an InP–InAlGaAs–InAlAs double heterojunction bipolar transistor with strained InGaAs quantum wells incorporated in the p-type base region. The laser exhibits a peak wavelength λ∼1544nm when biased in the forward active mode in the common-emitter configuration. A threshold current IB=10mA is observed.
Photoluminescence from localized states in disordered indium nitride
Authors: Bansal Bhavtosh , Kadir Abdul , Bhattacharya Arnab , Moshchalkov V. V.
Published: July 2008

Photoluminescence spectra from disordered InN were studied in very high magnetic fields. The samples had Gaussian spectra with low temperature emission peaks at 0.82 and 0.98eV, respectively. The average spatial extent of the excitonic wave functions, inferred from the diamagnetic shift, is only 2–3nm. This shows that the recombination is from an ensemble of highly localized states within a landscape of a smooth (classical) disorder potential of strength of the order of 10meV. The anomalies in the temperature dependence of the photoluminescence peak and linewidth give further support to the picture of trapped photoexcited carriers.
Ablation of liver cancer cells in vitro by a plasma needle
Authors: Zhang Xianhui , Li Maojin , Zhou Rouli , Feng Kecheng , Yang Size
Published: July 2008

A plasma needle using a dielectric barrier discharge reactor at atmospheric pressure with a funnel-shaped nozzle was developed. The preliminary characteristics of the plume and applications to the ablation of cultured human hepatocellular carcinoma (HCC) BEL-7402 cell line were presented. The effect of oxygen, which was injected into argon plasma afterglow region through a steel tube, was studied. The efficiency of argon-oxygen plasma depends sensitively on the oxygen concentration in argon plasma. Large differences between spectra in atmosphere and those in Dulbecco’s modified eagle medium are found. It is found that ultraviolet rays, O, OH, and Ar radicals can reach the bottom of solution and act on HCC cells and there is an optimum input power to get the most radicals.
Multiphoton microscopy based on four-wave mixing of colloidal quantum dots
Authors: Masia Francesco , Langbein Wolfgang , Borri Paola
Published: July 2008

We demonstrate a novel multiphoton imaging modality based on the detection of four-wave mixing (FWM) from colloidal nanoparticles. This third-order signal is excited and detected in resonance with the ground-state excitonic transition of CdSe∕ZnS quantum dots. We measure transversal and axial resolutions of 140 and 590nm, respectively, significantly improved compared to the one-photon diffraction limit. The coherent FWM signal is detected using a heterodyne technique which rejects incoherent background for improved image contrast compared to fluorescence methods. As sensitivity limit, we estimate a minimum number of 10dots∕Hz detectable in the focal volume.
Ion exchange in glass using femtosecond laser irradiation
Authors: Kanehira Shingo , Miura Kiyotaka , Hirao Kazuyuki
Published: July 2008

We explain the occurrence of ion exchange and an index profile around the focal point inside a commercial crown glass formed by femtosecond laser irradiation. The index profile in the photoinduced area has a ring-shaped pattern, which indicates that local densification occurred in the glass. An irregular surface reflecting the density distribution is formed around the focal point by dry etching process using a focused ion beam. By the irradiation of femtosecond laser pulses, the effect of ion exchange between the focal point and the surrounding area is also observed in the area in which local densification occurred.
High-sensitivity pesticide detection via silicon nanowires-supported acetylcholinesterase-based electrochemical sensors
Authors: Su Shao , He Yao , Zhang Mingliang , Yang Kun , Song Shiping , Zhang Xiaohong , Fan Chunhai , Lee Shuit-Tong
Published: July 2008

We report the use of a silicon-based nanocomplex, i.e., gold nanoparticles-coated silicon nanowires, for the improvement of acetylcholinesterase (AChE)-based electrochemical sensors for pesticide detection. Owing to the high electrical conductivity of the nanocomplex and its compatibility with the enzyme, the sensor exhibited significantly enhanced performance. The AChE enzyme bound to the surface possessed Michaelis–Menton constant of 81μM, resembling that in its free form. The sensor showed rapid response toward substrate acetylcholine in the concentration range of 1.0μM–1.0mM. This AChE nanosensor could detect as low as 8ng∕L dichlorvos, an organophosphate pesticide.
Shifting transition states in the unfolding of a large ankyrin repeat protein
Authors: Werbeck Nicolas D. , Rowling Pamela J. E. , Chellamuthu Vasuki R. , Itzhaki Laura S.
Published: July 2008

The 33-amino-acid ankyrin motif comprises a β-turn followed by two anti-parallel α-helices and a loop and tandem arrays of the motif pack in a linear fashion to produce elongated structures characterized by short-range interactions. In this article we use site-directed mutagenesis to investigate the kinetic unfolding mechanism of D34, a 426-residue, 12-ankyrin repeat fragment of the protein ankyrinR. The data are consistent with a model in which the N-terminal half of the protein unfolds first by unraveling progressively from the start of the polypeptide chain to form an intermediate; in the next step, the C-terminal half of the protein unfolds via two pathways whose transition states have either the early or the late C-terminal ankyrin repeats folded. We conclude that the two halves of the protein unfold by different mechanisms because the N-terminal moiety folds and unfolds in the context of a folded C-terminal moiety, which therefore acts as a “seed” and confers a unique directionality on the process, whereas the C-terminal moiety folds and unfolds in the context of an unfolded N-terminal moiety and therefore behaves like a single-domain ankyrin repeat protein, having a high degree of symmetry and consequently more than one unfolding pathway accessible to it.
Nitrite reductase activity of myoglobin regulates respiration and cellular viability in myocardial ischemia-reperfusion injury
Authors: Hendgen-Cotta Ulrike B. , Merx Marc W. , Shiva Sruti , Schmitz Joel , Becher Stefanie , Klare Johann P. , Steinhoff Heinz-Jürgen , Goedecke Axel , Schrader Jürgen , Gladwin Mark T. , Kelm Malte , Rassaf Tienush
Published: July 2008

The nitrite anion is reduced to nitric oxide (NO
•
) as oxygen tension decreases. Whereas this pathway modulates hypoxic NO
•
signaling and mitochondrial respiration and limits myocardial infarction in mammalian species, the pathways to nitrite bioactivation remain uncertain. Studies suggest that hemoglobin and myoglobin may subserve a fundamental physiological function as hypoxia dependent nitrite reductases. Using myoglobin wild-type (
+/+
) and knockout (
−/−
) mice, we here test the central role of myoglobin as a functional nitrite reductase that regulates hypoxic NO
•
generation, controls cellular respiration, and therefore confirms a cytoprotective response to cardiac ischemia-reperfusion (I/R) injury. We find that myoglobin is responsible for nitrite-dependent NO
•
generation and cardiomyocyte protein iron-nitrosylation. Nitrite reduction to NO
•
by myoglobin dynamically inhibits cellular respiration and limits reactive oxygen species generation and mitochondrial enzyme oxidative inactivation after I/R injury. In isolated myoglobin
+/+
but not in myoglobin
−/−
hearts, nitrite treatment resulted in an improved recovery of postischemic left ventricular developed pressure of 29%.
In vivo
administration of nitrite reduced myocardial infarction by 61% in myoglobin
+/+
mice, whereas in myoglobin
−/−
mice nitrite had no protective effects. These data support an emerging paradigm that myoglobin and the heme globin family subserve a critical function as an intrinsic nitrite reductase that regulates responses to cellular hypoxia and reoxygenation. myoglobin knockout mice
BRCA1 and Tip60 determine the cellular response to ultraviolet irradiation through distinct pathways
Authors: Kranz Dominique , Dohmesen Christoph , Dobbelstein Matthias
Published: July 2008

The histone acetyltransferase Tip60 regulates the apoptotic response to ultraviolet (UV) irradiation. A previously suggested mechanism for this regulation consists of the ability of Tip60 to coactivate transcription by the tumor suppressor p53. In this study, we show that Tip60 is required for the early DNA damage response (DDR) to UV, including the phosphorylation of histone 2AX, c-Jun N-terminal kinases (JNKs), and ataxia telangiectasia–related substrates. In contrast, p53 was not required for UV-induced DDR. Rather, p53 accumulation by either knockdown of Mdm2 or addition of an Mdm2 inhibitor, Nutlin-3, before irradiation strongly attenuated the UV-induced DDR and increased cell survival. This protective effect of preaccumulated p53 was mediated, at least in part, by the increased expression of CDKN1A/p21, subsequent down-regulation of BRCA1, and impaired JNK activation accompanied by decreased association of replication protein A with chromatin. We conclude that Tip60 enables UV-induced DDR signaling even in the absence of p53, whereas preaccumulated p53 suppresses UV-induced DDR by reducing the levels of BRCA1.
Playing both sides: nucleophosmin between tumor suppression and oncogenesis
Authors: Di Fiore Pier Paolo
Published: July 2008

Nucleophosmin (NPM) is frequently mutated in acute myeloid leukemias and is thought to act as both a proto-oncogene and a tumor suppressor. Although genetic and molecular evidence has shed light on the mechanisms of NPM-mediated tumor suppression, the potential role of NPM mutants as oncogenes remains ill defined. Now, new data provide a straightforward mechanism for this latter function, as NPM is shown to regulate the stability and the function of MYC. Remarkably, the same leitmotif of “placing a critical cell regulator in the wrong place at the wrong time” appears to underscore all the cancer-promoting activities of mutated NPM.
Immune-driven recombination and loss of control after HIV superinfection
Authors: Streeck Hendrik , Li Bin , Poon Art F.Y. , Schneidewind Arne , Gladden Adrianne D. , Power Karen A. , Daskalakis Demetre , Bazner Suzane , Zuniga Rosario , Brander Christian , Rosenberg Eric S. , Frost Simon D.W. , Altfeld Marcus , Allen Todd M.
Published: July 2008

After acute HIV infection, CD8+ T cells are able to control viral replication to a set point. This control is often lost after superinfection, although the mechanism behind this remains unclear. In this study, we illustrate in an HLA-B27+ subject that loss of viral control after HIV superinfection coincides with rapid recombination events within two narrow regions of Gag and Env. Screening for CD8+ T cell responses revealed that each of these recombination sites (∼50 aa) encompassed distinct regions containing two immunodominant CD8 epitopes (B27-KK10 in Gag and Cw1-CL9 in Env). Viral escape and the subsequent development of variant-specific de novo CD8+ T cell responses against both epitopes were illustrative of the significant immune selection pressures exerted by both responses. Comprehensive analysis of the kinetics of CD8 responses and viral evolution indicated that the recombination events quickly facilitated viral escape from both dominant WT- and variant-specific responses. These data suggest that the ability of a superinfecting strain of HIV to overcome preexisting immune control may be related to its ability to rapidly recombine in critical regions under immune selection pressure. These data also support a role for cellular immune pressures in driving the selection of new recombinant forms of HIV.
Voltage Clamp Fluorimetry Reveals a Novel Outer Pore Instability in a Mammalian Voltage-gated Potassium Channel
Authors: Vaid Moninder , Claydon Thomas W. , Rezazadeh Saman , Fedida David
Published: July 2008

Voltage-gated potassium (Kv) channel gating involves complex structural rearrangements that regulate the ability of channels to conduct K+ ions. Fluorescence-based approaches provide a powerful technique to directly report structural dynamics underlying these gating processes in Shaker Kv channels. Here, we apply voltage clamp fluorimetry, for the first time, to study voltage sensor motions in mammalian Kv1.5 channels. Despite the homology between Kv1.5 and the Shaker channel, attaching TMRM or PyMPO fluorescent probes to substituted cysteine residues in the S3–S4 linker of Kv1.5 (M394C-V401C) revealed unique and unusual fluorescence signals. Whereas the fluorescence during voltage sensor movement in Shaker channels was monoexponential and occurred with a similar time course to ionic current activation, the fluorescence report of Kv1.5 voltage sensor motions was transient with a prominent rapidly dequenching component that, with TMRM at A397C (equivalent to Shaker A359C), represented 36 ± 3% of the total signal and occurred with a τ of 3.4 ± 0.6 ms at +60 mV (n = 4). Using a number of approaches, including 4-AP drug block and the ILT triple mutation, which dissociate channel opening from voltage sensor movement, we demonstrate that the unique dequenching component of fluorescence is associated with channel opening. By regulating the outer pore structure using raised (99 mM) external K+ to stabilize the conducting configuration of the selectivity filter, or the mutations W472F (equivalent to Shaker W434F) and H463G to stabilize the nonconducting (P-type inactivated) configuration of the selectivity filter, we show that the dequenching of fluorescence reflects rapid structural events at the selectivity filter gate rather than the intracellular pore gate.
Linking Exponential Components to Kinetic States in Markov Models for Single-Channel Gating
Authors: Shelley Christopher , Magleby Karl L.
Published: July 2008

Discrete state Markov models have proven useful for describing the gating of single ion channels. Such models predict that the dwell-time distributions of open and closed interval durations are described by mixtures of exponential components, with the number of exponential components equal to the number of states in the kinetic gating mechanism. Although the exponential components are readily calculated (Colquhoun and Hawkes, 1982, Phil. Trans. R. Soc. Lond. B. 300:1–59), there is little practical understanding of the relationship between components and states, as every rate constant in the gating mechanism contributes to each exponential component. We now resolve this problem for simple models. As a tutorial we first illustrate how the dwell-time distribution of all closed intervals arises from the sum of constituent distributions, each arising from a specific gating sequence. The contribution of constituent distributions to the exponential components is then determined, giving the relationship between components and states. Finally, the relationship between components and states is quantified by defining and calculating the linkage of components to states. The relationship between components and states is found to be both intuitive and paradoxical, depending on the ratios of the state lifetimes. Nevertheless, both the intuitive and paradoxical observations can be described within a consistent framework. The approach used here allows the exponential components to be interpreted in terms of underlying states for all possible values of the rate constants, something not previously possible.
Nav1.4 Deregulation in Dystrophic Skeletal Muscle Leads to Na+ Overload and Enhanced Cell Death
Authors: Hirn Carole , Shapovalov George , Petermann Olivier , Roulet Emmanuelle , Ruegg Urs T.
Published: July 2008

Duchenne muscular dystrophy (DMD) is a hereditary degenerative disease manifested by the absence of dystrophin, a structural, cytoskeletal protein, leading to muscle degeneration and early death through respiratory and cardiac muscle failure. Whereas the rise of cytosolic Ca2+ concentrations in muscles of mdx mouse, an animal model of DMD, has been extensively documented, little is known about the mechanisms causing alterations in Na+ concentrations. Here we show that the skeletal muscle isoform of the voltage-gated sodium channel, Nav1.4, which represents over 90% of voltage-gated sodium channels in muscle, plays an important role in development of abnormally high Na+ concentrations found in muscle from mdx mice. The absence of dystrophin modifies the expression level and gating properties of Nav1.4, leading to an increased Na+ concentration under the sarcolemma. Moreover, the distribution of Nav1.4 is altered in mdx muscle while maintaining the colocalization with one of the dystrophin-associated proteins, syntrophin α-1, thus suggesting that syntrophin is an important linker between dystrophin and Nav1.4. Additionally, we show that these modifications of Nav1.4 gating properties and increased Na+ concentrations are strongly correlated with increased cell death in mdx fibers and that both cell death and Na+ overload can be reversed by 3 nM tetrodotoxin, a specific Nav1.4 blocker.
EPoS: a modular software framework for phylogenetic analysis
Authors: Griebel Thasso , Brinkmeyer Malte , Böcker Sebastian
Published: July 2008

Summary: Estimating Phylogenies of Species (EPoS) is a modular software framework for phylogenetic analysis, visualization and data management. It provides a plugin-based system that integrates a storage facility, a rich user interface and the ability to easily incorporate new methods, functions and visualizations. EPoS ships with persistent data management, a set of well-known phylogenetic algorithms and a multitude of tree visualization methods and layouts. Implemented algorithms cover distance-based tree construction, consensus trees and various graph-based supertree methods. The rendering system can be customized for, say, different edge and node styles.

Availability: Executables and source code are available under the LGPL license at http://www.bio.informatik.uni-jena.de/epos.

Contact:  thasso@minet.uni-jena.de

Supplementary information: The homepage contains tutorials and documentation for both users and programmers who want to develop plugins and extensions.
Rice Aroma and Flavor: A Literature Review
Authors: Champagne Elaine T.
Published: July 2008

Descriptive sensory analysis has identified over a dozen different aromas and flavors in rice. Instrumental analyses have found over 200 volatile compounds present in rice. However, after over 30 years of research, little is known about the relationships between the numerous volatile compounds and aroma/flavor. A number of oxidation products have been tagged as likely causing stale flavor. However, the amounts of oxidation products, singly or collectively, that need to be present for rice to have stale or rancid flavor have not been established. Only one compound, 2‐acetyl‐1‐pyrroline (2‐AP; popcorn aroma) has been confirmed to contribute a characteristic aroma. Furthermore, 2‐AP is the only volatile compound in which the relationship between its concentration in rice and sensory intensity has been established. This article discusses the challenges of measuring aroma and flavor instrumentally and by human sensory panels and reviews research examining the effects of genetic, preharvest, and postharvest factors on volatile compound profiles and the aroma and flavor of cooked rice.
Quality Trait Variation in Major Hard Red Spring Wheat Cultivars Released in North Dakota Since 1968
Authors: Underdahl J. L. , Mergoum M. , Schatz B. , Ransom J. K.
Published: July 2008

Over the last 40 years, grain yield of hard red spring wheat (HRSW) (Triticum aestivum L.) has increased dramatically in North Dakota and neighboring regions. This yield increase has caused some concern that recent higher yielding cultivars might be released at the expense of quality performance. A two‐year study was initiated in 2004 to examine the changes in quality performance of HRSW cultivars released by North Dakota State University (NDSU) over the past 40 years. The experiment was conducted in North Dakota at three and two sites in 2004 and 2005, respectively. The study included 33 HRSW genotypes laid out in a randomized complete‐block design with four replicates. Grain protein content, flour‐extraction yield, mixogram scores, Falling Number, glutograph scores, water absorption, dough character score, and loaf volumes did not vary significantly with year of release. Linear regression of cultivar means on year of release showed an annual increase in crumb color score of 0.4%/yr since 1968. Grain volume weight showed a significant and positive correlation with crumb color score (r = 0.62, P < 0.01). Given the yield increase achieved over the past 40 years, the data in this study suggest an increase in grain protein yield per hectare with no decline in breadmaking quality.
Physical Changes of Mesona Blumes Gum/Starch Mixed Gel with Sugars
Authors: Feng Tao , Gu Zhengbiao , Jin Zhengyu , Zhuang Haining
Published: July 2008

Mesona Blumes gum (MBG) is extracted from Mesona Blumes, which is an annual herb distributed throughout Southeast Asia and South China that has been used for medicinal functions in folk culture. More recently, it has been the focus of research for its potential food ingredient applications, such as meat binders. To evaluate the physical properties of these MBG/starch mixed gels with sugars, the viscographic viscosity, gel strength, elastic modulus, cold water solubility, water holding capacity, electronic conductivity, and pH were determined. Glucose had little influence on the physical properties of MBG/starch mixed gels, while sucrose could affect MBG/starch mixed gels to a large degree. It was concluded that various sugars played different roles in the formation of MBG/starch mixed gel. Amylographic viscosity, gel strength, and elastic modulus analysis, indicate that glucose could enhance the swelling of starch granules at concentrations of 0–75 mmol/L but at <25 mmol/L sucrose could facilitate the swelling of starch granules and beyond that it would inhibit the swelling of starch granules. SEM micrographs suggest that the MBG/starch system with glucose had more orderly and densely fibrous structures than the MBG/starch system with sucrose.
Redistribution of 16 Fusarium Toxins During Commercial Dry Milling of Maize
Authors: Schollenberger M. , Müller H.‐M. , Rüfle M. , Suchy S. , Drochner W.
Published: July 2008

The content of 13 A‐ and B‐type trichothecenes, zearalenone, as well as α‐ and β‐zearalenol was determined in products processed from raw maize by dry milling in an industrial plant. Two batches of samples were investigated derived from different lots of raw maize. Each of the toxins investigated was found in at least one of the samples analyzed, with up to 13 toxins co‐occurring within one sample. For both batches, toxins were either not detected or their content was low in raw and tempered maize, grits, and two types of flour. Markedly higher concentrations were found in screenings, bran, germ, or germ meal. The results suggest a similar redistribution during dry milling of maize for the whole spectrum of Fusarium toxins analyzed. In germ oil, only 15‐acetyldeoxynivalenol, zearalenone, HT‐2 toxin, and T‐2 toxin were detected due to the higher lipophilic properties of these substances compared with the other toxins found in the basing germ. This is the first time that the redistribution of a spectrum of 16 Fusarium toxins has been measured in a single dry‐milling study.
Effect of Iron Source on Color and Appearance of Micronutrient‐Fortified Corn Flour Tortillas
Authors: Richins A. T. , Burton K. E. , Pahulu H. F. , Jefferies L. , Dunn M. L.
Published: July 2008

Iron deficiency anemia is a widespread occurrence. Consequently, iron is commonly added in cereal fortification programs. However, many iron sources cause undesirable sensory changes, especially color changes, in the food being fortified. This study evaluated the effect of different iron sources on CIE L*a*b* color values and sensory color perception in fortified corn tortillas. Corn masa flour was fortified with micronutrient premix containing vitamins, zinc, and one of eight iron compounds. Iron sources included ferrous fumarate (F), ferrous sulfate (S), ferric orthophosphate (OP), ferrous lactate (L), ferrous gluconate (G), ferric pyrophosphate (PP), sodium iron (III)‐EDTA, and A‐131 electrolytic iron (E), with addition levels adjusted based on bioavailability. Control (Ct) samples were prepared with all micronutrients except iron. All iron‐fortified tortillas had lower L* values and were significantly darker than control tortillas. Based on instrumental color values and Mexican regulatory recommendations, five treatments were selected for further testing. A difference‐from‐control sensory test was conducted comparing PP, E, OP, F, and S with Ct tortillas. Sensory rankings were C t > E = PP > OP > F > S. A‐131 electrolytic iron is recommended for fortification of corn tortillas due to minimal effect on color and significantly lower cost than other iron sources evaluated.
Experimental heating reveals nest temperature affects nestling condition in tree swallows (
Tachycineta bicolor
)
Authors: Pérez Jonathan H , Ardia Daniel R , Chad Elise K , Clotfelter Ethan D
Published: July 2008

Investment in one life-history stage can have delayed effects on subsequent life-history stages within a single reproductive bout. We experimentally heated tree swallow (
Tachycineta bicolor
) nests during incubation to test for effects on parental and nestling conditions. Females incubating in heated boxes maintained higher body condition and fed nestlings at higher rates. We cross-fostered nestlings and found that young nestlings (4–7 days old) incubated in heated nests had higher body condition and body mass, regardless of treatment status of their rearing parent. However, older nestlings which were fed by heated females maintained higher condition and body mass regardless of treatment status of their incubating parent. These results indicate that investment in one life-history stage can have multiple pathways of carry-over effects on future life-history stages.
Size-selective dispersal of
Daphnia
resting eggs by backswimmers (
Notonecta maculata
)
Authors: van de Meutter Frank , Stoks Robby , de Meester Luc
Published: July 2008

Freshwater zooplankton is increasingly used to study effects of dispersal on community and metacommunity structure. Yet, it remains unclear how zooplankton disperses. Clearly, birds and wind play a significant role as zooplankton dispersal agents, but they may not always be the main vectors. This experimental study shows that a cosmopolitan aquatic insect,
Notonecta
, can be an important vector of cladoceran resting eggs (ephippia). Dispersing
Notonecta
frequently transported ephippia during flight, with a bias towards smaller ephippia in two species. A similar trend was present at the species level:
Daphnia
species with smaller ephippia were more often dispersed, suggesting that
Notonecta
could generate specific colonist communities. In addition, buoyancy appeared a critical trait, as non-floating ephippia of
Daphnia magna
were never dispersed. Our data suggest that
Notonecta
could be important dispersers of
Daphnia
, and that knowledge of dispersal dynamics of
Notonecta
may be used to predict
Daphnia
dispersal, colonization and resilience to disturbance.
Genetic variation of St. Louis encephalitis virus
Authors: May Fiona J. , Li Li , Zhang Shuliu , Guzman Hilda , Beasley David W. C. , Tesh Robert B. , Higgs Stephen , Raj Pushker , Bueno Rudy , Randle Yvonne , Chandler Laura , Barrett Alan D. T.
Published: July 2008

St. Louis encephalitis virus (SLEV) has been regularly isolated throughout the Americas since 1933. Previous phylogenetic studies involving 62 isolates have defined seven major lineages (I–VII), further divided into 14 clades. In this study, 28 strains isolated in Texas in 1991 and 2001–2003, and three older, previously unsequenced strains from Jamaica and California were sequenced over the envelope protein gene. The inclusion of these new sequences, and others published since 2001, has allowed better delineation of the previously published SLEV lineages, in particular the clades of lineage II. Phylogenetic analysis of 106 isolates identified 13 clades. All 1991 and 2001–2003 isolates from Nueces, Jefferson and Harris Counties (Texas Gulf Coast) group in clade IIB with other isolates from these counties isolated during the 1980s and 1990s. This lack of evidence for introduction of novel strains into the Texas Gulf Coast over a long period of time is consistent with overwintering of SLEV in this region. Two El Paso isolates, both from 2002, group in clade VA with recent Californian isolates from 1998–2001 and some South American strains with a broad temporal range. Overall, these data are consistent with multiple introductions of SLEV from South America into North America, and provide support for the hypothesis that in most situations, SLEV circulates within a locality, with occasional incursions from other areas. Finally, SLEV has much lower nucleotide (10.1 %) and amino acid variation (2.8 %) than other members of the Japanese encephalitis virus complex (maximum variation 24.6 % nucleotide and 11.8 % amino acid).
Identification of novel porcine and bovine parvoviruses closely related to human parvovirus 4
Authors: Lau Susanna K. P. , Woo Patrick C. Y. , Tse Herman , Fu Clara T. Y. , Au Wing-Ka , Chen Xin-Chun , Tsoi Hoi-Wah , Tsang Thomas H. F. , Chan Joanna S. Y. , Tsang Dominic N. C. , Li Kenneth S. M. , Tse Cindy W. S. , Ng Tak-Keung , Tsang Owen T. Y. , Zheng Bo-Jian , Tam Sidney , Chan Kwok-Hung , Zhou Boping , Yuen Kwok-Yung
Published: July 2008

Human parvovirus 4 (PARV4), a recently discovered parvovirus found exclusively in human plasma and liver tissue, was considered phylogenetically distinct from other parvoviruses. Here, we report the discovery of two novel parvoviruses closely related to PARV4, porcine hokovirus (PHoV) and bovine hokovirus (BHoV), from porcine and bovine samples in Hong Kong. Their nearly full-length sequences were also analysed. PARV4-like viruses were detected by PCR among 44.4 % (148/333) of porcine samples (including lymph nodes, liver, serum, nasopharyngeal and faecal samples), 13 % (4/32) of bovine spleen samples and 2 % (7/362) of human serum samples that were sent for human immunodeficiency virus and hepatitis C virus antibody tests. Three distinct parvoviruses were identified, including two novel parvoviruses, PHoV and BHoV, from porcine and bovine samples and PARV4 from humans, respectively. Analysis of genome sequences from seven PHoV strains, from three BHoV strains and from one PARV4 strain showed that the two animal parvoviruses were most similar to PARV4 with 61.5–63 % nt identities and, together with PARV4 (HHoV), formed a distinct cluster within the family Parvoviridae. The three parvoviruses also differed from other parvoviruses by their relatively large predicted VP1 protein and the presence of a small unique conserved putative protein. Based on these results, we propose a separate genus, Hokovirus, to describe these three parvoviruses. The co-detection of porcine reproductive and respiratory syndrome virus, the agent associated with the recent ‘high fever’ disease outbreaks in pigs in China, from our porcine samples warrants further investigation.
Severe acute respiratory syndrome coronavirus 3a protein activates the mitochondrial death pathway through p38 MAP kinase activation
Authors: Padhan Kartika , Minakshi Rinki , Towheed Mohammad Aatif Bin , Jameel Shahid
Published: July 2008

The molecular mechanisms governing severe acute respiratory syndrome coronavirus-induced pathology are not fully understood. Virus infection and some individual viral proteins, including the 3a protein, induce apoptosis. However, the cellular targets leading to 3a protein-mediated apoptosis have not been fully characterized. This study showed that the 3a protein modulates the mitochondrial death pathway in two possible ways. Activation of caspase-8 through extrinsic signal(s) caused Bid activation. In the intrinsic pathway, there was activation of caspase-9 and cytochrome c release from the mitochondria. This was the result of increased Bax oligomerization and higher levels of p53 in 3a protein-expressing cells, which depended on the activation of p38 MAP kinase (MAPK) in these cells. For p38 activation and apoptosis induction, the 3a cytoplasmic domain was sufficient. In direct Annexin V staining assays, the 3a protein-expressing cells showed increased apoptosis that was attenuated with the p38 MAPK inhibitor SB203580. A block in nuclear translocation of the STAT3 transcription factor in cells expressing the 3a protein was also observed. These results have been used to present a model of 3a-mediated apoptosis.
Delivery of single-chain antibodies (scFvs) directed against the 37/67 kDa laminin receptor into mice via recombinant adeno-associated viral vectors for prion disease gene therapy
Authors: Zuber Chantal , Mitteregger Gerda , Schuhmann Natascha , Rey Clémence , Knackmuss Stefan , Rupprecht Wolfgang , Reusch Uwe , Pace Claudia , Little Melvyn , Kretzschmar Hans A. , Hallek Michael , Büning Hildegard , Weiss Stefan
Published: July 2008

The 37/67 kDa laminin receptor (LRP/LR) acts as a receptor for prions providing a promising target for the treatment of prion diseases. Recently, we selected anti-LRP/LR single-chain antibodies (scFvs) and proved a reduction of the peripheral PrPScpropagation by passive immunotransfer into scrapie-infected mice. Here, we report the development of anin vivogene delivery system based on adeno-associated virus (AAV) vectors expressing scFvs-S18 and -N3 directed against LRP/LR. Transduction of neuronal and non-neuronal cells with recombinant (r)AAV serotype 2 vectors encoding scFv-S18, -N3 and -C9 verified the efficient secretion of the antibodies. These vectors were administered via stereotactic intracerebral microinjection into the hippocampus of C57BL/6 mice, followed by intracerebral inoculation with 10 % RML at the same site 2 weeks post-injection of rAAV. After 90 days post-infection, scFv-S18 and -N3 expression resulted in the reduction of peripheral PrPScpropagation by approximately 60 and 32 %, respectively, without a significant prolongation of incubation times and survival. Proof of rAAV vector DNA in spleen samples by real-time PCR strongly suggests a transport or trafficking of rAAV from the brain to the spleen, resulting in rAAV-mediated expression of scFv followed by reduced PrPSclevels in the spleen most likely due to the blockage of the prion receptor LRP/LR by scFv.
The intestinal stem cell
Authors: Barker Nick , van de Wetering Marc , Clevers Hans
Published: July 2008

The epithelium of the adult mammalian intestine is in a constant dialog with its underlying mesenchyme to direct progenitor proliferation, lineage commitment, terminal differentiation, and, ultimately, cell death. The epithelium is shaped into spatially distinct compartments that are dedicated to each of these events. While the intestinal epithelium represents the most vigorously renewing adult tissue in mammals, the stem cells that fuel this self-renewal process have been identified only recently. The unique epithelial anatomy makes the intestinal crypt one of the most accessible models for the study of adult stem cell biology. This review attempts to provide a comprehensive overview of four decades of research on crypt stem cells.
Genome-wide location analysis reveals a role of TFIIS in RNA polymerase III transcription
Authors: Ghavi-Helm Yad , Michaut Magali , Acker Joël , Aude Jean-Christophe , Thuriaux Pierre , Werner Michel , Soutourina Julie
Published: July 2008

TFIIS is a transcription elongation factor that stimulates transcript cleavage activity of arrested RNA polymerase II (Pol II). Recent studies revealed that TFIIS has also a role in Pol II transcription initiation. To improve our understanding of TFIIS function in vivo, we performed genome-wide location analysis of this factor. Under normal growth conditions, TFIIS was detected on Pol II-transcribed genes, and TFIIS occupancy was well correlated with that of Pol II, indicating that TFIIS recruitment is not restricted to NTP-depleted cells. Unexpectedly, TFIIS was also detected on almost all Pol III-transcribed genes. TFIIS and Pol III occupancies correlated well genome-wide on this novel class of targets. In vivo, some dst1 mutants were partly defective in tRNA synthesis and showed a reduced Pol III occupancy at the restrictive temperature. In vitro transcription assays suggested that TFIIS may affect Pol III start site selection. These data provide strong in vivo and in vitro evidence in favor of a role of TFIIS as a general Pol III transcription factor.
QUALX: a computer program for qualitative analysis using powder diffraction data
Authors: Altomare Angela , Cuocci Corrado , Giacovazzo Carmelo , Moliterni Anna , Rizzi Rosanna
Published: July 2008

QUALXis a new computer program for phase identification using powder diffraction data. It uses the Powder Diffraction File database, where a search for the phase best matching the experimental powder diffraction pattern is carried out. The program is characterized by a high level of automation: the traditional steps aimed at interpreting the experimental pattern before the search (background estimation, peak search, peak intensity evaluation) are executed automatically. The search may be carried outviaconstraints on compound name and/or chemical elements. In addition, several graphical options requested interactively enable the user to perform zero point correction evaluation,Kα2stripping and smoothing. The program, written in Fortran95 and C++, runs on PCs under the Windows XP operating system. It is supported by a very effective graphical interface.
Order, disorder and structural modulations in Bi–Fe–W–O–Br Sillén–Aurivillius intergrowths
Authors: Ávila-Brande David , Landa-Cánovas Ángel R. , Otero-Díaz L. Carlos
Published: July 2008

Transmission electron microscopy observations on a new complex oxybromide with nominal composition Bi4Fe1/3W2/3O8Br, heated at high temperature, reveal the transformation of its basic structure yielding two types of crystals. The first crystal type shows ordered and disordered extended defects leading to a new family of intergrowths between one Sillén block and n Aurivillius blocks and occasionally between one Aurivillius block and n Sillén blocks. The second type presents a compositionally modulated structure, determined by electron diffraction, with an average composition Bi4Fe1/2W1/2O8 − δBr and unit-cell parameters a = (1/γ) 3.8, b = 3.8, c = 14.5 Å (γ = 0.10–0.15) in the superspace group Immm[(1 − γ)00] no. 71.1.
Toll‐like receptor 2 agonist Pam3CSK4 enhances the induction of antigen‐specific tolerance via the sublingual route
Authors: Lombardi V. , Van Overtvelt L. , Horiot S. , Moussu H. , Chabre H. , Louise A. , Balazuc A.‐M. , Mascarell L. , Moingeon P.
Published: July 2008

Background
Sublingual immunotherapy (SLIT) has been established in humans as a safe and efficacious treatment for type I respiratory allergies.

Objective
In this study, we compared three Toll‐like receptor (TLR) 2 ligands (Pam3CSK4, Porphyromonas gingivalis lipopolysaccharide and lipoteichoic acid) as potential adjuvants for sublingual allergy vaccines.

Methods
These molecules were tested in co‐cultures of adjuvant‐pre‐treated dendritic cells (DCs) with murine naïve CD4+ T lymphocytes. Patterns of cytokine production, phenotype, proliferation and gene expression were analysed by ELISA, cytofluorometry and quantitative PCR, respectively. TLR2 ligands were subsequently tested in a model of SLIT in BALB/c mice sensitized with ovalbumin (OVA).

Results
Among the three TLR2 ligands tested, the synthetic lipopeptide Pam3CSK4 is the most potent inducer of IL‐12p35 and IL‐10 gene expression in murine bone marrow‐derived DCs, as well as in purified oral myeloid DCs. Only Pam3CSK4‐treated DCs induce IFN‐γ and IL‐10 secretion by naïve CD4+ T cells. Sublingual administration of Pam3CSK4 together with the antigen in BALB/c mice sensitized to OVA decreases airway hyperresponsiveness as well as OVA‐specific T‐helper type 2 (Th2) responses in cervical lymph nodes dramatically.

Conclusion
Pam3CSK4 induces Th1/regulatory T cell responses, and as such, is a valid candidate adjuvant for sublingual allergy vaccines.
Impact of specific sensitization on asthma and rhinitis in young Brazilian and Chilean adults
Authors: Rona R. J. , Vargas C. , Vianna E. O. , Bustos P. , Bettiol H. , Amigo H. , Mackenney J. , Barbieri M. A.
Published: July 2008

Background
The pattern of associations and the attributable fractions (AF) of atopic conditions due to specific sensitizations vary between countries.

Objective
To assess the level of associations and AF between sensitization to five allergens and atopic conditions in two settings.

Methods
We studied 2063 Brazilians and 1231 Chileans of both sexes using representative samples selected at birth in the 1970s. Information on asthma and rhinitis was based on the European Community Respiratory Health Survey questionnaire. We assessed bronchial hyperresponsiveness (BHR) to methacholine and sensitization to Dermatophagoides pteronyssinus, cat, dog, grass blend and Alternaria alternata.

Results
The prevalence of sensitization to one or more allergens was 50% in Brazilians and 22% in Chileans. The level of associations varied according to the outcome used. Strong associations between sensitization and asthma, defined as wheeze or awakening with breathlessness at night and positive BHR, were found for each of the five allergens in Chileans [varying from odds ratio (OR) 3.24, 95% confidence interval (CI) 1.47, 7.15 for D. pteronyssinus to 8.44, 95% CI 3.82, 18.66 for cat], whereas the level of associations was restricted to D. pteronyssinus, cat and dog in Brazilians and was somewhat weaker (highest OR 3.90, 95% CI 2.80–5.44). The AF of sensitization on asthma was 54% in Brazil and 44% in Chile. D. pteronyssinus and cat made an independent contribution to asthma in the two samples. The patterns of associations between sensitization and rhino‐conjunctivitis were similar to those for asthma.

Conclusion
The associations between sensitization, and asthma and rhinitis were high in Chile and moderately high in Brazil, but the AF were higher in Brazil, reflecting a higher prevalence of sensitization. In Brazil, dust mite had the greatest impact on atopic conditions while in Chile several allergens had an impact. Sensitization is as serious a problem in Chile and Brazil as in developed countries.
Circulating IGF‐I levels are associated with increased biventricular contractility in top‐level rowers
Authors: Vitale Giovanni , Galderisi Maurizio , Colao Annamaria , Innelli Pasquale , Guerra Germano , Guerra Ermelinda , Dini Frank Lloyd , Orio Francesco Jr , Soscia Antonio , De Divitiis Oreste , Lombardi Gaetano
Published: July 2008

Background  The intensive physical activity is often associated with cardiac changes.

Objectives  (i) To evaluate the IGF‐I system and myocardial structure and function by standard Doppler echocardiography and Tissue Doppler in athletes and sedentary controls; and (ii) to determine any relationship between IGF‐I system and echocardiographic parameters.

Methods  Nineteen male top‐level rowers and 19 age‐matched healthy sedentary male controls underwent blood determination of fasting serum IGF‐I, IGFBP‐3 and acid‐labile subunit levels and standard Doppler echocardiography combined with pulsed Tissue Doppler of posterior septal wall, left ventricular (LV) lateral mitral annulus and right ventricular (RV) tricuspid annulus. Myocardial presystolic (PSm), systolic (Sm), the ratio of early diastolic (Em) to atrial (Am) velocities as well as myocardial time intervals were calculated.

Results  Rowers had higher serum IGF‐I levels (P = 0·04), higher biventricular cavity dimensions and wall thicknesses compared to controls. They also had better LV and RV myocardial function than controls. In the rowers, IGF‐I was associated with LV ejection fraction (r = 0·50, P = 0·03), RV PSm velocity (r = 0·55, P = 0·01) and with RV myocardial precontraction time (r = −0·57, P = 0·01). These associations remained significant after adjusting for age and heart rate.

Conclusions  Top‐level athletes showed higher IGF‐I levels and a better myocardial performance than controls, particularly for the RV systolic activity. The independent correlations between IGF‐I and systolic parameters of the left (ejection fraction) and right (PSm velocity and precontraction time) ventricles may possibly indicate a role of IGF‐I system in the modulation of myocardial inotropism in athletes. Further studies are needed to confirm this hypothesis.