bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic structure of chromia aerogels from soft x-ray absorption spectroscopy
Authors: Kucheyev S. O. , Sadigh B. , Baumann T. F. , Wang Y. M. , Felter T. E. , van Buuren T. , Gash A. E. , Satcher J. H. , Hamza A. V.
Published: June 2007

The electronic structure of ultralow density nanoporous chromia monoliths (aerogels) is studied by soft x-ray absorption near-edge structure (XANES) spectroscopy. These aerogels are prepared by the epoxide sol-gel method. High-resolution O K edge and Cr L2,3 edge XANES spectra of aerogels (before and after thermal annealing at 550°C) are compared with spectra of microcrystalline α-Cr2O3 and orthorhombic CrO3 powders, α-Cr2O3 (0001) and (11¯02) single crystals, and an unrelaxed amorphous phase of full-density Cr2O3. Spectra are interpreted based on the results of crystal-field multiplet calculations (for Cr L2,3 edge) and ab initio spin-polarized density functional theory calculations with and without a Hubbard-type on-site Coulomb repulsion (for O K edge). Results show that the electronic structure of as-prepared aerogels, with a large fraction of undercoordinated surface atoms, is significantly different from that of bulk α-Cr2O3, CrO3, or amorphous Cr2O3. Thermal treatment transforms the as-prepared amorphous aerogel into α-Cr2O3 nanopowder.
Evidence of electron accumulation at nonpolar surfaces of InN nanocolumns
Authors: Calleja E. , Grandal J. , Sánchez-García M. A. , Niebelschütz M. , Cimalla V. , Ambacher O.
Published: June 2007

High-quality InN nanocolumns grown by molecular beam epitaxy on n-type Si(111) have been electrically characterized by atomic force microscopy. Current-voltage characteristics were measured on InN nanocolumns with similar heights but different diameters. The conductivity scales the nanocolumns reciprocal diameter, pointing to the nanocolumn lateral surface as the main conduction path. These results, opposing those found in undoped GaN nanocolumns where the conductivity is rather independent of the diameter (conduction through the volume), agree well with a model that predicts electron accumulation by Fermi level pinning within the conduction band on nonpolar (m plane) InN surfaces reconstructed under In-rich conditions.
Introduction: Optimization in networks
Authors: Motter Adilson E. , Toroczkai Zoltan
Published: June 2007

The recent surge in the network modeling of complex systems has set the stage for a new era in the study of fundamental and applied aspects of optimization in collective behavior. This Focus Issue presents an extended view of the state of the art in this field and includes articles from a large variety of domains in which optimization manifests itself, including physical, biological, social, and technological networked systems.
Liquid transport generated by a flashing field-induced wettability ratchet
Authors: John Karin , Thiele Uwe
Published: June 2007

The authors develop a model for ratchet-driven macroscopic transport of a continuous phase. The transport relies on a field-induced dewetting-spreading cycle of a liquid film based on a switchable, spatially asymmetric, periodic interaction of the free surface of the film and the solid substrate. The concept is exemplified using an evolution equation for a dielectric liquid film under an inhomogeneous voltage. The authors analyze the influence of the various phases of the ratchet cycle on the transport properties. Conditions for maximal transport and the efficiency of transport under load are discussed.
High efficiency protocrystalline silicon/microcrystalline silicon tandem cell with zinc oxide intermediate layer
Authors: Myong Seung Yeop , Sriprapha Kobsak , Miyajima Shinsuke , Konagai Makoto , Yamada Akira
Published: June 2007

The authors develop a hydrogenated protocrystalline silicon (pc-Si:H)/hydrogenated microcrystalline silicon (μc-Si:H) double-junction solar cell structure employing a boron-doped zinc oxide (ZnO:B) intermediate layer. Highly stable intrinsic pc-Si:H and μc-Si:H absorbers are prepared by a 60MHz very-high-frequency plasma-enhanced chemical vapor deposition technique. Degenerate ZnO:B intermediate and back reflectors are deposited via a metal organic chemical vapor deposition technique. Because the ZnO:B intermediate layer reduces the potential thickness for the pc-Si:H absorber in the top cell, this double-juncion structure is a promising candidate to fabricate highly stable Si-based thin-film solar cells. Consequently, the high conversion efficiency of 12.0% is achieved.
Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer
Authors: Sheu Jinn-Kong , Lu Y. S. , Lee Min-Lum , Lai W. C. , Kuo C. H. , Tun Chun-Ju
Published: June 2007

GaN-based light-emitting diodes (LEDs) with indium tin oxide (ITO)/Ga-doped ZnO (GZO) composite oxide films serving as a transparent contact layer (TCL) were demonstrated. In this study, the wall-plug efficiency of LEDs (LED-III) with textured ITO/GZO composite TCL can be markedly improved by 200% and 45% of magnitude as compared to conventional LEDs with Ni∕Au TCL(LED-II) and planar ITO/GZO TCL(LED-I), respectively. Compared to LED-II, this enhancement is due to the enhanced light extraction efficiency of ITO/GZO composite TCL with high transparency. Compared to LED-I, ZnO-based TCL with a higher refractive index (n∼2.0) allows further enhancement of light extraction through the creation of a textured structure on transparent conductive oxide TCL deposited on the top surface of LEDs. In addition, the ITO/GZO composite TCL with a thickness of 550nm is far larger than that of Ni∕Au TCL with a thickness of approximately 15nm. Therefore, in addition to the effect of high transparency, the thicker ITO/GZO TCL with low lateral resistance would also act as a current-spreading layer leading to an enhancement of light extraction.
A diatom species index for bioassessment of Australian rivers
Authors: Chessman Bruce C. , Bate Nina , Gell Peter A. , Newall Peter
Published: June 2007

The Diatom Index for Australian Rivers (DIAR), originally developed at the genus level, was reformulated at the species level with data from diatom sampling of rivers in the Australian Capital Territory, New South Wales, Queensland, South Australia and Victoria. The resulting Diatom Species Index for Australian Rivers (DSIAR) was significantly correlated with the ARCE (Assessment of River Condition, Environment) index developed in the Australian National Land and Water Resources Audit (NLWRA), and with nine of the ARCE’s constituent indices and sub-indices, across 395 river reaches in south-eastern Australia. These correlations were generally stronger than those shown by the biological index that was used to assess river condition in the NLWRA, the ARCB (Assessment of River Condition, Biota) index based on macroinvertebrates and the Australian River Assessment System (AUSRIVAS). At a finer spatial scale, DSIAR was strongly and significantly correlated with measures of catchment urbanisation for streams in the eastern suburbs of Melbourne, Victoria. DSIAR scores across south-eastern Australia bore little relationship to the latitude, longitude or altitude of sampling sites, suggesting that DSIAR is not greatly affected by macro-geographical position. In addition, DSIAR scores did not vary greatly among small-scale hydraulic environments within a site. DSIAR appears to have potential as a broad-scale indicator of human influences on Australian rivers, especially the effects of agricultural and urban land use, and also for impact studies at a local scale. Further evaluation is warranted to test the sensitivity of the index to natural variables such as catchment geology, and to assess its performance in northern, western and inland Australia.
Phylogenetic relationships in the lizard genus Diplodactylus Gray and resurrection of Lucasium Wermuth (Gekkota, Diplodactylidae)
Authors: Oliver Paul M. , Hutchinson Mark N. , Cooper Steven J. B.
Published: June 2007

Diplodactylid geckos offer a model system for investigating the biogeographic history of Australia and adaptive radiations in the arid zone, but there is considerable uncertainty in the systematics of several key genera. We used sequence data from mitochondrial DNA to carry out a comprehensive analysis of phylogenetic relationships of geckos in the genus Diplodactylus. Parsimony and Bayesian analyses were highly concordant and allocated all species to one of two monophyletic clades, one comprising the species placed in the vittatus and conspicillatus species groups, the other comprising species placed in the stenodactylus and steindachneri species groups, plus D. byrnei, formerly in the vittatus group. The distinctness of these two clades is supported by external morphology of the digits, body and limb proportions, and osteology of the bones in the orbital region, and we use these characters to formally define the two clades as genera. We revive and expand the genus Lucasium for D. byrnei, D. steindachneri and the stenodactylus group, with the other species staying in a redefined Diplodactylus. The monotypic Rhynchoedura is distinct from Lucasium, although the Bayesian mtDNA analysis (but not parsimony) gives some support for a sister-group relationship between Lucasium and Rhynchoedura. Molecular data suggest that each of these clades represents a distinct radiation into semiarid and arid terrestrial habitats during the mid-Tertiary, well before the hypothesised Pliocene onset of major aridification.
The nuclear factor of activated T cells in pulmonary arterial hypertension can be therapeutically targeted
Authors: Bonnet Sebastien , Rochefort Gael , Sutendra Gopinath , Archer Stephen L. , Haromy Alois , Webster Linda , Hashimoto Kyoko , Bonnet Sandra N. , Michelakis Evangelos D.
Published: June 2007

In pulmonary arterial hypertension (PAH), antiapoptotic, proliferative, and inflammatory diatheses converge to create an obstructive vasculopathy. A selective down-regulation of the Kv channel Kv1.5 has been described in human and animal PAH. The resultant increase in intracellular free Ca
2+
([Ca
2+
]
i
) and K
+
([K
+
]
i
) concentrations explains the pulmonary artery smooth muscle cell (PASMC) contraction, proliferation and resistance to apoptosis. The recently described PASMC hyperpolarized mitochondria and increased bcl-2 levels also contribute to apoptosis resistance in PAH. The cause of the Kv1.5, mitochondrial, and inflammatory abnormalities remains unknown. We hypothesized that these abnormalities can be explained in part by an activation of NFAT (nuclear factor of activated T cells), a Ca
2+
/calcineurin-sensitive transcription factor. We studied PASMC and lungs from six patients with and four without PAH and blood from 23 PAH patients and 10 healthy volunteers. Compared with normal, PAH PASMC had decreased Kv current and Kv1.5 expression and increased [Ca
2+
]
i
, [K
+
]
i
, mitochondrial potential (ΔΨm), and bcl-2 levels. PAH but not normal PASMC and lungs showed activation of NFATc2. Inhibition of NFATc2 by VIVIT or cyclosporine restored Kv1.5 expression and current, decreased [Ca
2+
]
i
, [K
+
]
i
, bcl-2, and ΔΨm, leading to decreased proliferation and increased apoptosis
in vitro. In vivo
, cyclosporine decreased established rat monocrotaline-PAH. NFATc2 levels were increased in circulating leukocytes in PAH versus healthy volunteers. CD3-positive lymphocytes with activated NFATc2 were seen in the arterial wall in PAH but not normal lungs. The generalized activation of NFAT in human and experimental PAH might regulate the ionic, mitochondrial, and inflammatory remodeling and be a therapeutic target and biomarker.
The Insulin-like Growth Factor-I–mTOR Signaling Pathway Induces the Mitochondrial Pyrimidine Nucleotide Carrier to Promote Cell Growth
Authors: Floyd Suzanne , Favre Cedric , Lasorsa Francesco M. , Leahy Madeline , Trigiante Giuseppe , Stroebel Philipp , Marx Alexander , Loughran Gary , O'Callaghan Katie , Marobbio Carlo M.T. , Slotboom Dirk J. , Kunji Edmund R.S. , Palmieri Ferdinando , O'Connor Rosemary
Published: June 2007

The insulin/insulin-like growth factor (IGF) signaling pathway to mTOR is essential for the survival and growth of normal cells and also contributes to the genesis and progression of cancer. This signaling pathway is linked with regulation of mitochondrial function, but how is incompletely understood. Here we show that IGF-I and insulin induce rapid transcription of the mitochondrial pyrimidine nucleotide carrier PNC1, which shares significant identity with the essential yeast mitochondrial carrier Rim2p. PNC1 expression is dependent on PI-3 kinase and mTOR activity and is higher in transformed fibroblasts, cancer cell lines, and primary prostate cancers than in normal tissues. Overexpression of PNC1 enhances cell size, whereas suppression of PNC1 expression causes reduced cell size and retarded cell cycle progression and proliferation. Cells with reduced PNC1 expression have reduced mitochondrial UTP levels, but while mitochondrial membrane potential and cellular ATP are not altered, cellular ROS levels are increased. Overall the data indicate that PNC1 is a target of the IGF-I/mTOR pathway that is essential for mitochondrial activity in regulating cell growth and proliferation.
A Novel Function of eIF2α Kinases as Inducers of the Phosphoinositide-3 Kinase Signaling Pathway
Authors: Kazemi Shirin , Mounir Zineb , Baltzis Dionissios , Raven Jennifer F. , Wang Shuo , Krishnamoorthy Jothi-Latha , Pluquet Olivier , Pelletier Jerry , Koromilas Antonis E.
Published: June 2007

Phosphoinositide-3 kinase (PI3K) plays an important role in signal transduction in response to a wide range of cellular stimuli involved in cellular processes that promote cell proliferation and survival. Phosphorylation of the α subunit of the eukaryotic translation initiation factor eIF2 at Ser51 takes place in response to various types of environmental stress and is essential for regulation of translation initiation. Herein, we show that a conditionally active form of the eIF2α kinase PKR acts upstream of PI3K and turns on the Akt/PKB-FRAP/mTOR pathway leading to S6 and 4E-BP1 phosphorylation. Also, induction of PI3K signaling antagonizes the apoptotic and protein synthesis inhibitory effects of the conditionally active PKR. Furthermore, induction of the PI3K pathway is impaired in PKR−/− or PERK−/− mouse embryonic fibroblasts (MEFs) in response to various stimuli that activate each eIF2α kinase. Mechanistically, PI3K signaling activation is indirect and requires the inhibition of protein synthesis by eIF2α phosphorylation as demonstrated by the inactivation of endogenous eIF2α by small interfering RNA or utilization of MEFs bearing the eIF2α Ser51Ala mutation. Our data reveal a novel property of eIF2α kinases as activators of PI3K signaling and cell survival.
Geranylgeranyl Diphosphate Synthase in Fission Yeast Is a Heteromer of Farnesyl Diphosphate Synthase (FPS), Fps1, and an FPS-like Protein, Spo9, Essential for Sporulation
Authors: Ye Yanfang , Fujii Makoto , Hirata Aiko , Kawamukai Makoto , Shimoda Chikashi , Nakamura Taro
Published: June 2007

Both farnesyl diphosphate synthase (FPS) and geranylgeranyl diphosphate synthase (GGPS) are key enzymes in the synthesis of various isoprenoid-containing compounds and proteins. Here, we describe two novel Schizosaccharomyces pombe genes, fps1+and spo9+, whose products are similar to FPS in primary structure, but whose functions differ from one another. Fps1 is essential for vegetative growth, whereas, a spo9 null mutant exhibits temperature-sensitive growth. Expression of fps1+, but not spo9+, suppresses the lethality of a Saccharomyces cerevisiae FPS-deficient mutant and also restores ubiquinone synthesis in an Escherichia coli ispA mutant, which lacks FPS activity, indicating that S. pombe Fps1 in fact functions as an FPS. In contrast to a typical FPS gene, no apparent GGPS homologues have been found in the S. pombe genome. Interestingly, although neither fps1+nor spo9+expression alone in E. coli confers clear GGPS activity, coexpression of both genes induces such activity. Moreover, the GGPS activity is significantly reduced in the spo9 mutant. In addition, the spo9 mutation perturbs the membrane association of a geranylgeranylated protein, but not that of a farnesylated protein. Yeast two-hybrid and coimmunoprecipitation analyses indicate that Fps1 and Spo9 physically interact. Thus, neither Fps1 nor Spo9 alone functions as a GGPS, but the two proteins together form a complex with GGPS activity. Because spo9 was originally identified as a sporulation-deficient mutant, we show here that expansion of the forespore membrane is severely inhibited in spo9Δ cells. Electron microscopy revealed significant accumulation membrane vesicles in spo9Δ cells. We suggest that lack of GGPS activity in a spo9 mutant results in impaired protein prenylation in certain proteins responsible for secretory function, thereby inhibiting forespore membrane formation.
TheTrans-Golgi Network Accessory Protein p56 Promotes Long-Range Movement of GGA/Clathrin-containing Transport Carriers and Lysosomal Enzyme Sorting
Authors: Mardones Gonzalo A. , Burgos Patricia V. , Brooks Doug A. , Parkinson-Lawrence Emma , Mattera Rafael , Bonifacino Juan S.
Published: June 2007

The sorting of acid hydrolase precursors at the trans-Golgi network (TGN) is mediated by binding to mannose 6-phosphate receptors (MPRs) and subsequent capture of the hydrolase-MPR complexes into clathrin-coated vesicles or transport carriers (TCs) destined for delivery to endosomes. This capture depends on the function of three monomeric clathrin adaptors named GGAs. The GGAs comprise a C-terminal “ear” domain that binds a specific set of accessory proteins. Herein we show that one of these accessory proteins, p56, colocalizes and physically interacts with the three GGAs at the TGN. Moreover, overexpression of the GGAs enhances the association of p56 with the TGN, and RNA interference (RNAi)-mediated depletion of the GGAs decreases the TGN association and total levels of p56. RNAi-mediated depletion of p56 or the GGAs causes various degrees of missorting of the precursor of the acid hydrolase, cathepsin D. In the case of p56 depletion, this missorting correlates with decreased mobility of GGA-containing TCs. Transfection with an RNAi-resistant p56 construct, but not with a p56 construct lacking the GGA-ear–interacting motif, restores the mobility of the TCs. We conclude that p56 tightly cooperates with the GGAs in the sorting of cathepsin D to lysosomes, probably by enabling the movement of GGA-containing TCs.
Immunohistochemical identification of type I and type III collagen and chondroitin sulphate in human pre‐dentine: a correlative FEI‐SEM/TEM study
Authors: Orsini G. , Ruggeri A. , Mazzoni A. , Papa V. , Piccirilli M. , Falconi M. , Di Lenarda R. , Breschi L.
Published: June 2007

Aim  To identify type I‐ (I‐CF) and type III‐collagen fibrils (III‐CF) and chondroitin 4/6 sulphate (CS) within human pre‐dentine by means of a correlative analysis under field emission in‐lens‐scanning electron microscopy (FEI‐SEM) and transmission electron microscopy (TEM).

Methodology  Human‐extracted teeth were obtained and submitted to either a pre‐embedding or a post‐embedding immunolabelling procedure using monoclonal primary antibodies anti‐I‐CF, anti‐III‐CF and anti‐CS. Gold‐conjugated secondary antibodies were coupled to primary antibodies to visualize labelling under the electron beam. Correlative labelling patterns were obtained for I‐CF and CS under both FEI‐SEM and TEM.

Results  Field emission in lens‐SEM analysis revealed an intricate three‐dimensional network of I‐CF and CS clarifying the intimate relationship between the two main components of the pre‐dentine organic matrix. TEM analysis revealed odontoblasts exhibiting intracellular labelling for CS, which became more intense and diffuse over the pre‐dentine organic matrix. The same diffuse immunoreaction was revealed for I‐CF, whereas a weak immunolocalization of III‐CF was found scattered throughout the pre‐dentine layer and over the collagen fibrils.

Conclusions  Both the pre‐ and post‐embedding immunohistochemical approaches have led to the visualization of CF‐ and CS‐labelling distribution within the pre‐dentine layer, adding further knowledge on the elucidation of collagen–proteoglycans interaction in the organic matrix of human dental roots.
Mineral trioxide aggregate pulpotomy of a primary second molar in a patient with agenesis of the permanent successor
Authors: Moretti A. B. S. , Oliveira T. M. , Sakai V. T. , Santos C. F. , Machado M. A. A. M. , Abdo R. C. C.
Published: June 2007

Aim  To describe a pulpotomy with mineral trioxide aggregate in a primary second molar with no permanent successor.

Summary  Coronal pulpotomy was performed on a carious primary molar with no permanent successor in a 7‐year‐old child. Follow‐up examinations 24 months later revealed that the treatment was successful in preserving the tooth and the vitality of its pulp.

Key learning point  Mineral trioxide aggregate might be considered as an alternative wound dressing for pulpotomy in primary molars, preserving pulp vitality and prolonging the useful life of the tooth.
Association of a high‐molecular weight arginine‐binding protein of Fusobacterium nucleatum ATCC 10953 with adhesion to secretory immunoglobulin A and coaggregation with Streptococcus cristatus
Authors: Edwards A. M. , Grossman T. J. , Rudney J. D.
Published: June 2007

Introduction:  Fusobacterium nucleatum coaggregates with a diverse range of bacterial species, and binds to host tissues and proteins such as immunoglobulin. These interactions may support the attachment of a variety of organisms to oral surfaces and can facilitate the invasion of soft tissues. We hypothesized that coaggregation with streptococci and immunoglobulin binding may occur by a common adhesin sensitive to l‐arginine.

Methods:  Repeated mixing of F. nucleatum with non‐immune secretory immunoglobulin A (S‐IgA) and recovery of non‐agglutinating cells isolated a spontaneous mutant (isolate 21) of F. nucleatum that was defective in S‐IgA binding. Wild‐type and mutant F. nucleatum were compared by coaggregation and adhesion assays.

Results:  Isolate 21 exhibited significantly reduced S‐IgA binding and coaggregation with oral streptococci but not with Porphyromonas gingivalis. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that the mutant was deficient compared to wild‐type for a single protein of approximately 360 kilodaltons. The corresponding protein was isolated from wild‐type F. nucleatum protein preparations by coprecipitation with arginine–agarose beads. This protein was able to bind both Streptococcus cristatus and S‐IgA. Mass spectrometry analysis indicated that this protein was closely related to putative autotransporter proteins in other F. nucleatum strains and was a 100% match to the deduced amino acid sequence of a 10,638‐base‐pair open reading frame in the incomplete genome sequence of F. nucleatum ATCC 10953. Peptides identified by MS‐MS analysis spanned most of the predicted amino acid sequence, suggesting that the mature protein is not subject to postsecretory cleavage.

Conclusion:  Coaggregation represents a novel function within the autotransporter class of proteins, which are often associated with virulence.
The dual nature of time preparation: neural activation and suppression revealed by transcranial magnetic stimulation of the motor cortex
Authors: Davranche Karen , Tandonnet Christophe , Burle Boris , Meynier Chloé , Vidal Franck , Hasbroucq Thierry
Published: June 2007

Single‐pulse transcranial magnetic stimulations (TMSs) of the motor cortex (M1) were performed in order to decipher the neural mechanisms of time preparation. We varied the degree to which it was possible to prepare for the response signal in a choice reaction time (RT) task by employing either a short (500 ms) or a long (2500 ms) foreperiod in separate blocks of trials. Transcranial magnetic stimulations were delivered during these foreperiods in order to study modulations in both the size of the motor evoked potential (MEP) and the duration of the silent period (SP) in tonically activated response agonists. Motor evoked potential area and silent period duration were assumed to reflect, respectively, the excitability of the cortico‐spinal pathway and the recruitment of inhibitory cortical interneurons. Shorter reaction times were observed with the shorter foreperiod, indicating that a better level of preparation was attained for the short foreperiod. Silent period duration decreased as time elapsed during the foreperiod and this decrement was more pronounced for the short foreperiod. This result suggests that time preparation is accompanied by a removal of intracortical inhibition, resulting in an activation. Motor evoked potential area decreased over the course of the short foreperiod, but not over the long foreperiod, revealing that time preparation involves the inhibition of the cortico‐spinal pathway. We propose that cortico‐spinal inhibition secures the development of cortical activation, preventing erroneous premature responding.
Resting EEG sources correlate with attentional span in mild cognitive impairment and Alzheimer's disease
Authors: Babiloni Claudio , Cassetta Emanuele , Binetti Giuliano , Tombini Mario , Del Percio Claudio , Ferreri Florinda , Ferri Raffaele , Frisoni Giovanni , Lanuzza Bartolo , Nobili Flavio , Parisi Laura , Rodriguez Guido , Frigerio Leonardo , Gurzì Mariella , Prestia Annapaola , Vernieri Fabrizio , Eusebi Fabrizio , Rossini Paolo M.
Published: June 2007

Previous evidence has shown that resting delta and alpha electroencephalographic (EEG) rhythms are abnormal in patients with Alzheimer's disease (AD) and its potential preclinical stage (mild cognitive impairment, MCI). Here, we tested the hypothesis that these EEG rhythms are correlated with memory and attention in the continuum across MCI and AD. Resting eyes‐closed EEG data were recorded in 34 MCI and 53 AD subjects. EEG rhythms of interest were delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), and beta 2 (20–30 Hz). EEG cortical sources were estimated by low‐resolution brain electromagnetic tomography (LORETA). These sources were correlated with neuropsychological measures such as Rey list immediate recall (word short‐term memory), Rey list delayed recall (word medium‐term memory), Digit span forward (immediate memory for digits probing focused attention), and Corsi span forward (visuo‐spatial immediate memory probing focused attention). A statistically significant negative correlation (Bonferroni corrected, P < 0.05) was observed between Corsi span forward score and amplitude of occipital or temporal delta sources across MCI and AD subjects. Furthermore, a positive correlation was shown between Digit span forward score and occipital alpha 1 sources (Bonferroni corrected, P < 0.05). These results suggest that cortical sources of resting delta and alpha rhythms correlate with neuropsychological measures of immediate memory based on focused attention in the continuum of MCI and AD subjects.
The Cav2.3 calcium channel antagonist SNX‐482 reduces dorsal horn neuronal responses in a rat model of chronic neuropathic pain
Authors: Matthews Elizabeth A. , Bee Lucy A. , Stephens Gary J. , Dickenson Anthony H.
Published: June 2007

Neuropathic pain is a difficult state to treat, characterized by alterations in sensory processing that can include allodynia (touch‐evoked pain). Evidence exists for nerve damage‐induced plasticity in both transmission and modulatory systems, including changes in voltage‐dependent calcium channel (VDCC) expression and function; however, the role of Cav2.3 calcium channels has not clearly been defined. Here, the effects of SNX‐482, a selective Cav2.3 antagonist, on sensory transmission at the spinal cord level have been investigated in the rat. The spinal nerve ligation (SNL) model of chronic neuropathic pain [Kim & Chung, (1992)Pain, 50, 355–363] was used to induce mechanical allodynia, as tested on the ipsilateral hindpaw. In vivo electrophysiological measurements of dorsal horn neuronal responses to innocuous and noxious electrical and natural stimuli were made after SNL and compared to sham‐operated animals. Spinal SNX‐482 (0.5–4 µg/50 µL) exerted dose‐related inhibitions of noxious C‐fibre‐ and Aδ‐fibre‐mediated neuronal responses in conditions of neuropathy, but not in sham‐operated animals. Measures of spinal cord hyperexcitability and nociception were most susceptible to SNX‐482. In contrast, non‐noxious Aβ‐mediated responses were not affected by SNX‐482. Moreover, responses to innocuous mechanical and also thermal stimuli were more sensitive to SNX‐482 in SNL than control animals. This study is the first to demonstrate an antinociceptive role for SNX‐482‐sensitive channels in dorsal horn neurons during neuropathy. These data are consistent with plasticity in CaV2.3 calcium channel expression and suggest a potential selective target to reduce nociceptive transmission during conditions of nerve damage.
Peripheral oxygen‐sensing cells directly modulate the output of an identified respiratory central pattern generating neuron
Authors: Bell Harold J. , Inoue Takuya , Shum Kelly , Luk Collin , Syed Naweed I.
Published: June 2007

Breathing is an essential homeostatic behavior regulated by central neuronal networks, often called central pattern generators (CPGs). Despite ongoing advances in our understanding of the neural control of breathing, the basic mechanisms by which peripheral input modulates the activities of the central respiratory CPG remain elusive. This lack of fundamental knowledge vis‐à‐vis the role of peripheral influences in the control of the respiratory CPG is due in large part to the complexity of mammalian respiratory control centres. We have therefore developed a simpler invertebrate model to study the basic cellular and synaptic mechanisms by which a peripheral chemosensory input affects the central respiratory CPG. Here we report on the identification and characterization of peripheral chemoreceptor cells (PCRCs) that relay hypoxia‐sensitive chemosensory information to the known respiratory CPG neuron right pedal dorsal 1 in the mollusk Lymnaea stagnalis. Selective perfusion of these PCRCs with hypoxic saline triggered bursting activity in these neurons and when isolated in cell culture these cells also demonstrated hypoxic sensitivity that resulted in membrane depolarization and spiking activity. When cocultured with right pedal dorsal 1, the PCRCs developed synapses that exhibited a form of short‐term synaptic plasticity in response to hypoxia. Finally, osphradial denervation in intact animals significantly perturbed respiratory activity compared with their sham counterparts. This study provides evidence for direct synaptic connectivity between a peripheral regulatory element and a central respiratory CPG neuron, revealing a potential locus for hypoxia‐induced synaptic plasticity underlying breathing behavior.
Olfactory information converges in the amygdaloid cortex via the piriform and entorhinal cortices: observations in the guinea pig isolated whole‐brain preparation
Authors: Kajiwara Riichi , Tominaga Takashi , Takashima Ichiro
Published: June 2007

The amygdaloid cortex (AC) has reciprocal connections with the entorhinal cortex (EC) and also receives projections from the olfactory bulb and the piriform cortex (PC). To assess the possibility that the AC and EC represent functionally coupled structures in the olfactory stream of information, we investigated the propagation pattern of neural activity in olfactory cortices − PC, AC and EC − using optical recordings with voltage‐sensitive dyes in the guinea pig in vitro isolated whole‐brain preparation. We observed two distinct pathways that convey neural activation evoked by olfactory nerve stimulation: a medial pathway from the PC to the AC, and a lateral pathway from the PC to the lateral EC along the rhinal sulcus. Besides being activated directly via the medial pathway, the AC was activated a second time via activity that propagated from the lateral EC. Lesion experiments revealed that the lateral pathway close to the rhinal sulcus is crucial for neural activation of the EC. Consistent with this activation pattern, we observed two separate, sharp downward deflections in field potential recordings, and we recorded synaptic potentials with multiple peaks from single neurons in the AC. Our findings suggest that the AC and EC are functionally coupled during olfactory information processing, and that this functional linkage may allow the AC to integrate olfactory sensation with information retained or processed in the EC.
Orienting and maintenance of spatial attention in audition and vision: an event‐related brain potential study
Authors: Salmi Juha , Rinne Teemu , Degerman Alexander , Alho Kimmo
Published: June 2007

We examined the effects of orienting and maintenance of attention on performance and event‐related brain potentials (ERPs) in audition and vision. Our subjects selectively attended to sounds or pictures in one location (Maintenance of attention) or alternated the focus of their auditory or visual attention between left and right locations (Orienting of attention) in order to detect and press a response button to infrequent targets among the attended stimuli. Reaction times were longer in the Auditory Orienting condition and hit rates were lower and false alarm rates higher in the Visual Orienting condition than in the corresponding Maintenance conditions. Comparison of ERPs to the attended and unattended stimuli in the Auditory and Visual Orienting and Maintenance conditions revealed attention‐related modulations of ERPs. In each modality, ERPs to attended stimuli were negatively displaced in relation to unattended stimuli at 100–250 ms from stimulus onset. These negative differences (Nds) showed modality‐specific distributions and they were larger over the hemisphere contralateral to the attended sounds and pictures than over the ipsilateral hemisphere. Moreover, the Nd was larger in the Auditory Orienting condition than in the Auditory Maintenance condition, while no such difference was observed in the visual modality. In addition to the Nd, attended visual stimuli elicited a late positive response (LPR) in both Orienting and Maintenance conditions. In contrast to our recent functional magnetic resonance imaging (fMRI) study employing the same experimental paradigm and indicating orienting‐related activity in the frontal and parietal cortices, no ERP responses specifically related to orienting were found in either modality.
Glucocorticoid receptors in the basolateral nucleus of amygdala are required for postreactivation reconsolidation of auditory fear memory
Authors: Jin Xin‐Chun , Lu Yu‐Fei , Yang Xiao‐Fei , Ma Lan , Li Bao‐Ming
Published: June 2007

It is well known that initial consolidation requires de novo gene transcription and protein synthesis in order for memory to become stable. The consolidated memory again becomes labile and temporarily sensitive to disruption when retrieved, requiring a reconsolidation process to become permanent. Although it is well established that glucocorticoid receptors (GR) in the basolateral nucleus of amygdala (BLA) are required for consolidation of fear memory, little is known about their role in reconsolidation of fear memory. In the present study, we first examined the effect of a GR antagonist on postconditioning consolidation of auditory fear memory (AFM). Intra‐BLA infusion of the GR antagonist RU486 0 h postconditioning impaired long‐term AFM, leaving short‐term AFM intact. RU486 had no effect if infusion was performed 6 h postconditioning. We then investigated the effect of the RU486 treatment on postretrieval reconsolidation of AFM. Severe amnesia took place when RU486 was infused into the BLA 0 h postretrieval (reactivation) of AFM, regardless of whether the retrieval was performed 1 day or 10 days postconditioning. RU486 produced no amnesia if the memory retrieval was omitted or if the drug was administered 6 h postretrieval. Treatment with RU486 0 h postretrieval produced no deficit in postretrieval short‐term memory but impaired postretrieval long‐term memory, and the amnesia exhibited no spontaneous recovery 6 days after retrieval. The present results provide strong evidence that glucocorticoid receptors in the BLA are required for reconsolidation as well as consolidation of AFM.
Plastic changes in the vibrissa motor cortex in adult rats after output suppression in the homotopic cortex
Authors: Maggiolini Emma , Veronesi Carlo , Franchi Gianfranco
Published: June 2007

After motor cortex damage, the unaffected homotopic cortex shows changes in motor output. The present experiments were designed to clarify the nature of these interhemispheric effects. We investigate the vibrissa motor cortex (VMC) output after activity suppression of the homotopic area in adult rats. Comparison was made of VMC output after lidocaine inactivation (L‐group) or quinolinic acid lesion (Q‐group) of the homotopic cortex. In the Q‐group, VMC mapping was performed 3 days (Q3Ds group), 2 weeks (Q2Ws group) and 4 weeks (Q4Ws group) after cortical lesion. In each animal, VMC output was assessed by mapping movements induced by intracortical microstimulation (ICMS) in both hemispheres (hemisphere ipsilateral and contralateral to injections). Findings demonstrated that, in the L‐group, the size of vibrissal representation was 39.5% smaller and thresholds required to evoke vibrissa movement were 46.3% higher than those in the Control group. There was an increase in the percentage of ineffective sites within the medial part of the VMC and an increase in the percentage of forelimb sites within the lateral part. Both the Q3Ds group and the L‐group led to a similar VMC reorganization (Q3Ds vs. L‐group, P > 0.05). In the Q2Ws group the VMC representation showed improvement in size (83.4% recovery compared with controls). The VMC showed recovery to normal output at 4 weeks after lesion (Control vs. Q4Ws group, P > 0.05). These results suggest that the VMC of the two hemispheres continuously interact through excitatory influences, preserving the normal output and inhibitory influences defining the border with the forelimb representation.
AAV‐mediated delivery of BDNF augments neurogenesis in the normal and quinolinic acid‐lesioned adult rat brain
Authors: Henry Rebecca A. , Hughes Stephanie M. , Connor Bronwen
Published: June 2007

Brain‐derived neurotrophic factor (BDNF) plays a major role in regulating the survival and fate of progenitor cells in the adult brain. In order to extend previous observations in the normal adult brain and advance our knowledge regarding the effect of BDNF on neurogenesis in the injured brain, this study directly compared the effect of BDNF on basal and injury‐induced neurogenesis in relation to progenitor cell distribution and levels of neuronal differentiation and survival. BDNF was overexpressed in the subventricular zone (SVZ) via recombinant adeno‐associated virus (AAV1/2) delivery, and newly generated cells were identified using bromodeoxyuridine (BrdU) labelling. Selective striatal cell loss was induced in a subgroup of rats by unilateral striatal injection of quinolinic acid (QA) 21 days after AAV1/2 injection. In the normal brain, BDNF overexpression significantly increased BrdU‐positive cell numbers in the rostral migratory stream, indicating enhanced progenitor cell migration. Following QA lesioning, we observed a reduction in BrdU immunoreactivity in the SVZ. Overexpression of BDNF restored BrdU‐positive cell numbers in the QA‐lesioned SVZ to that observed in the normal brain. Most significantly, BDNF enhanced the recruitment of progenitor cells to the QA‐lesioned striatum and promoted neuronal differentiation in both the normal and QA‐lesioned striatum. Our findings indicate that BDNF augments the recruitment, neuronal differentiation and survival of progenitor cells in both neurogenic and non‐neurogenic regions of the normal or QA‐lesioned brain. Enhanced expression of BDNF may therefore be a viable strategy for augmenting neurogenesis from endogenous progenitor cells.
Cyclic Fatigue Crack Growth in Three‐Point Bending PZT Ceramics under Electromechanical Loading
Authors: Narita Fumio , Shindo Yasuhide , Saito Fumitoshi
Published: June 2007

This paper investigates experimentally and analytically the cyclic fatigue crack growth in piezoelectric ceramics under electromechanical loading. Cyclic crack growth tests were conducted on lead zirconate titanate (PZT) ceramics subjected to dc electric fields, and a finite element analysis was used to calculate the maximum energy release rate for the permeable crack model. Based on bending experiments using single‐edge precracked‐beam specimens, cyclic fatigue crack growth rates are found to be sensitive to the maximum energy release rate and applied dc electric fields. Possible mechanisms for crack growth were discussed by scanning electron microscope examination of the fracture surface of the PZT ceramics.
Efficacy of single‐agent bortezomib vs. single‐agent thalidomide in patients with relapsed or refractory multiple myeloma: a systematic comparison
Authors: Prince H. Miles , Adena Michael , Smith Dell Kingsford , Hertel Judy
Published: June 2007

Objective:  To conduct a systematic review of the efficacy of single‐agent bortezomib vs. single‐agent thalidomide in patients with relapsed/refractory multiple.

Methods:  Publications in English from 1966 to June 2005 (MEDLINE, EMBASE, Cochrane library), publication reference lists, Janssen‐Cilag data‐on‐file and abstracts from recent multiple myeloma conferences were reviewed. Prospective studies containing at least a single arm of either treatment group with n≥30 were included. Studies adding dexamethasone for non‐responders were excluded. Statistical pooling was performed for response rate and overallsurvival.

Results:  One bortezomib study (n = 333, NEJM 2005, 352; 2487–98) and 15 thalidomide (n = 1007) studies met these criteria and were included. Patient baseline characteristics including age, gender, IgG : IgA, disease duration and beta‐2 microglobulin were well matched except that 48% of bortezomib patients had received prior thalidomide. Response rate, defined as serum M‐protein reduction ≥50%, was 53% for patients receiving bortezomib vs. 32% for thalidomide (P < 0.001, n = 10 studies). Response rate determined by European Group for Blood and Marrow Transplantation (EBMT) criteria was 41% for patients receiving bortezomib vs. 22% for thalidomide (P < 0.001, n = 4 studies).

Conclusion:  Bortezomib was associated with a significantly higher response rate and complete remission rate using both M‐protein and EBMT criteria.
Differentiation of Closely Related Fungi by Electronic Nose Analysis
Authors: Karlshøj K. , Nielsen P.V. , Larsen T.O.
Published: June 2007

ABSTRACT:  In this work the potential of electronic nose analysis for differentiation of closely related fungi has been described. A total of 20 isolates of the cheese‐associated species Geotrichum candidum, Penicillium camemberti, P. nordicum, and P. roqueforti and its closely related species P. paneum, P. carneum as well as the noncheese‐associated P. expansum have been investigated by electronic nose, GC‐MS, and LC‐MS analysis. The isolates were inoculated on yeast extract sucrose agar in 20‐mL headspace flasks and electronic nose analysis was performed daily for a 7‐d period. To assess which volatile metabolites the electronic nose potentially responded to, volatile metabolites were collected by diffusive sampling overnight onto tubes containing Tenax TA, between the 7th and 8th day of incubation. Volatiles were analyzed by gas chromatography coupled to mass spectrometry and the results indicated that mainly alcohols (ethanol, 2‐methyl‐1‐propanol, and 3‐methyl‐1‐butanol) and ketones (acetone, 2‐butanone, and 2‐pentanone) were produced at this stage. The volatile metabolite profile proved to be species specific. Nonvolatile metabolites were collected on the 8th day of incubation and mycotoxin analysis was performed by high pressure liquid chromatography coupled to a diode array detector and a time of flight mass spectrometer. Several mycotoxins were detected in samples from the species P. nordicum, P. roqueforti, P. paneum, P. carneum, and P. expansum. Differentiation of closely related mycotoxin producing fungi incubated on yeast extract sucrose agar has been achieved, indicating that there is a potential for predicting production of mycotoxins on food and feedstuffs by electronic nose analysis.
Irradiation in Combination with Higher Storage Temperatures Maintains Chip‐Making Quality of Potato
Authors: Kumar S. , Khade H.D. , Dhokane V.S. , Behere A.G. , Sharma A.
Published: June 2007

ABSTRACT:  Freshly harvested and well‐suberized potato (Solanum tuberosum) of varieties Kufri Jyoti, Lady Rosata, Kufri Laukar, and Hermises were processed by radiation at 78/149 Gy (Dmin/Dmax) dose and stored at 12 ± 2 °C for 8 mo from March to October for assessment of chip‐making quality. The firmness of the tubers in all the varieties processed remained unchanged during the period of storage. Chips of the desirable quality could be prepared from 7‐mo stored Lady Rosata, Hermises, and Kufri Jyoti varieties, whereas, in Kufri Laukar, the quality chips could be prepared with tubers stored not beyond 5 mo. In the present study, varietal differences were found to influence the chip‐making quality of irradiated potato. Tubers with high reducing and total sugar (>2%) were found to be unsuitable for chip‐making. The quality of chips, however, was not affected much by the change in internal color of the tuber during storage beyond 6 mo. The results suggested the efficacy of gamma irradiation for ensuring availability of the processing quality potato during lean periods from September to October.
Gelation Mechanism of Surimi Studied by 1H NMR Relaxation Measurements
Authors: Ahmad M.U. , Tashiro Y. , Matsukawa S. , Ogawa H.
Published: June 2007

ABSTRACT:  In order to elucidate the gelation mechanism of surimi, the temperature dependence of water proton spin–spin relaxation time (1H T2) has been described by a theoretical approach, in which the exposed protein surface is taken into account. Water 1H T2 measured for horse mackerel surimi in the presence of 2.5% NaCl was analyzed on the basis of the consideration for the denaturation and the aggregation of protein in order to explain the macroscopic structural change during the heating and the cooling processes. The temperature dependence of water 1H T2 and the fraction of rigid component gave a clear explanation for the gelation mechanism of surimi. Differential scanning calorimetry thermogram and dynamic viscoelastic measurements supported the results of nuclear magnetic resonance (NMR) measurements. It has been demonstrated that the measurement of NMR relaxation times is useful to describe the gelation mechanism of surimi.
Caffeine Content of Prepackaged National‐Brand and Private‐Label Carbonated Beverages
Authors: Chou K.‐H. , Bell L.N.
Published: June 2007

ABSTRACT:  Caffeine is a well‐known stimulant that is added as an ingredient to various carbonated soft drinks. Due to its stimulatory and other physiological effects, individuals desire to know the exact amount of caffeine consumed from these beverages. This study analyzed the caffeine contents of 56 national‐brand and 75 private‐label store‐brand carbonated beverages using high‐performance liquid chromatography. Caffeine contents ranged from 4.9 mg/12 oz (IGA Cola) to 74 mg/12 oz (Vault Zero). Some of the more common national‐brand carbonated beverages analyzed in this study with their caffeine contents were Coca‐Cola (33.9 mg/12 oz), Diet Coke (46.3 mg/12 oz), Pepsi (38.9 mg/12 oz), Diet Pepsi (36.7 mg/12 oz), Dr Pepper (42.6 mg/12 oz), Diet Dr Pepper (44.1 mg/12 oz), Mountain Dew (54.8 mg/12 oz), and Diet Mountain Dew (55.2 mg/12 oz). The Wal‐Mart store‐brand beverages with their caffeine contents were Sam's Cola (12.7 mg/12 oz), Sam's Diet Cola (13.3 mg/12 oz), Dr Thunder (30.6 mg/12 oz), Diet Dr Thunder (29.9 mg/12 oz), and Mountain Lightning (46.5 mg/12 oz). Beverages from 14 other stores were also analyzed. Most store‐brand carbonated beverages were found to contain less caffeine than their national‐brand counterparts. The wide range of caffeine contents in carbonated beverages indicates that consumers would benefit from the placement of caffeine values on food labels.