bluuebunny/crossref_metadata_2025 huggingface dataset:
Cooperative effects in photon statistics of molecular dimers with spectral diffusion
Authors: Šanda František , Mukamel Shaul
Published: March 2006

The two-point fluorescence intensity correlation function g(2)(t) and the Mandel parameter M(t) are calculated for a strongly pumped dimer of two-level molecules undergoing Gaussian-Markovian frequency fluctuations. The effects of detuning and saturation are examined. All fluctuation time scale regimes are explored using a continued fraction solution of the stochastic Liouville equation for the generating function. Bunching and antibunching are observed for slow and fast fluctuations, respectively. The short-time antibunching dip in g(2) and its variation with intermolecular coupling, the exciton annihilation rate, and laser detuning are studied.
Effect of the plasma instability on the beam intensity from RIKEN 18 GHz electron cyclotron resonance ion source
Authors: Higurashi Y. , Nakagawa T. , Kidera M. , Aihara T. , Kobayashi K. , Kase M. , Goto A. , Yano Y.
Published: March 2006

We measured the beam oscillation of RIKEN 18 GHz electron cyclotron resonance ion source for various conditions. In this experiment, the frequency of the beam oscillation increases with increasing the gas pressure and decreases with increasing rf power. The oscillation frequency is strongly dependent on the negative voltage of biased disk, i.e., the frequency increases with increasing the negative voltage. We observed that the frequency is strongly dependent on the mass of ionized gas.
On the structure and chemical bonding of Si62− and Si62− in NaSi6− upon Na+ coordination
Authors: Zubarev Dmitry Yu. , Alexandrova Anastassia N. , Boldyrev Alexander I. , Cui Li-Feng , Li Xi , Wang Lai-Sheng
Published: March 2006

Photoelectron spectroscopy was combined with ab initio calculations to elucidate the structure and bonding in Si62− and NaSi6−. Well-resolved electronic transitions were observed in the photoelectron spectra of Si6− and NaSi6− at three photon energies (355, 266, and 193nm). The spectra of NaSi6− were observed to be similar to those of Si6− except that the electron binding energies of the former are lower, suggesting that the Si6 motif in NaSi6− is structurally and electronically similar to that in Si6−. The electron affinities of Si6 and NaSi6 were measured fairly accurately to be 2.23±0.03eV and 1.80±0.05eV, respectively. Global minimum structure searches for Si62− and NaSi6− were performed using gradient embedded genetic algorithm followed by B3LYP, MP2, and CCSD(T) calculations. Vertical electron detachment energies were calculated for the lowest Si6− and NaSi6− structures at the CCSD(T)/6-311+G(2df), ROVGF/6-311+G(2df), UOVGF/6-311+G(2d), and time-dependent B3LYP/6-311+G(2df) levels of theory. Experimental vertical detachment energies were used to verify the global minimum structure for NaSi6−. Though the octahedral Si62−, analogous to the closo form of borane B6H62−, is the most stable form for the bare hexasilicon dianion, it is not the kernel for the NaSi6− global minimum. The most stable isomer of NaSi6− is based on a Si62− motif, which is distorted into C2v symmetry similar to the ground state structure of Si6−. The octahedral Si62− coordinated by a Na+ is a low-lying isomer and was also observed experimentally. The chemical bonding in Si62− and NaSi6− was understood using natural bond orbital, molecular orbital, and electron localization function analyses.
Cryogen-free superconducting magnet system for multifrequency electron paramagnetic resonance up to 12.1T
Authors: Smirnov Alex I. , Smirnova Tatyana I. , MacArthur Ryan L. , Good Jeremy A. , Hall Renny
Published: March 2006

Multifrequency and high field/high frequency (HF) electron paramagnetic resonance (EPR) is a powerful spectroscopy for studying paramagnetic spin systems ranging from organic-free radicals to catalytic paramagnetic metal ion centers in metalloproteins. Typically, HF EPR experiments are carried out at resonant frequencies ν=95–300GHz and this requires magnetic fields of 3.4–10.7T for electronic spins with g≈2.0. Such fields could be easily achieved with superconducting magnets, but, unlike NMR, these magnets cannot operate in a persistent mode in order to satisfy a wide range of resonant fields required by the experiment. Operating and maintaining conventional passively cooled superconducting magnets in EPR laboratories require frequent transfer of cryogens by trained personnel. Here we describe and characterize a versatile cryogen-free magnet system for HF EPR at magnetic fields up to 12.1T that is suitable for ramping the magnetic field over the entire range, precision scans around the target field, and/or holding the field at the target value. We also demonstrate that in a nonpersistent mode of operation the magnetic field can be stabilized to better than 0.3ppm∕h over 15h period by employing a transducer-controlled power supply. Such stability is sufficient for many HF EPR experiments. An important feature of the system is that it is virtually maintenance-free because it is based on a cryogen-free technology and therefore does not require any liquid cryogens (liquid helium or nitrogen) for operation. We believe that actively cooled superconducting magnets are ideally suited for a wide range of HF EPR experiments including studies of spin-labeled nucleic acids and proteins, single-molecule magnets, and metalloproteins.
Modified single photon counting modules for optimal timing performance
Authors: Rech I. , Labanca I. , Ghioni M. , Cova S.
Published: March 2006

A modification of a standard Perkin Elmer SPCM-AQR photon detector module that remarkably improves the photon timing performance is presented here. The modification consists of an additional timing circuit board, which is inserted in the module without modifying the original circuit board. The essential feature is a pulse pickup linear network, connected to the high-voltage terminal of the photodetector, which extracts a short pulse signal with fast rise, coincident with the rise of the avalanche current. The information about the photon arrival time is obtained by sensing the onset of the rise. At low counting rates (<105counts∕s) time-correlated photon counting tests show that the instrumental resolution function (IRF) thus obtained has full width at half maximum (FWHM) narrower by about 40% with respect to the original module. At higher counting rate, up to few Mcounts/s, the advantage is even more remarkable: The timing circuit practically eliminates the drawbacks that plague the original module, namely, a progressive increase of the FWHM and a progressive shift of the peak position of the IRF with increasing counting rate. The modified SPCM-AQR module is therefore suitable also for applications requiring subnanosecond time resolution at high and/or variable counting rate, such as fluorescent decay measurements, fluorescent lifetime imaging, single molecule detection and spectroscopy, and optical radar techniques.
A crossed coplanar waveguide design for ultrafast magnetization switching utilizing polymer insulation layers
Authors: Martín Pimentel P. , Hermsdoerfer S. J. , Nembach H. T. , Leven B. , Hillebrands B. , Trellenkamp S. , Wolff S.
Published: March 2006

A crossed coplanar waveguide design using polymer insulation layers is developed as a tool to experimentally investigate fast, precessional switching phenomena in view of applications in magnetic random access memory. The photosensitive polymer Cyclotene 4024™ (benzocyclobutene) is used as an electric insulation layer to realize a multilayer sample consisting of several different conducting and insulating layers. We report on the processing of Cyclotene 4024™ multilayers with optimized surface and electric insulating properties after hard cure. The micropatterned impedance matched coplanar waveguides have a bandwidth of 8.5GHz according to −2dB criterion, and for the −3dB criterion the bandwidth exceeds the measurement range of up to 15GHz. These values allow for short rise and fall times of the pulse for ultrafast magnetization dynamics measurements.
Charge transport of copper phthalocyanine single-crystal field-effect transistors stable above 100°C
Authors: Yamada Koichi , Takeya J. , Shigeto K. , Tsukagoshi K. , Aoyagi Y. , Iwasa Y.
Published: March 2006

Intrinsic charge transport of copper phthalocyanine single-crystal field-effect transistors is measured as function of temperature up to above 100°C. The conduction of the accumulated carriers shows hopping-type transport, so that the field-effect mobility increases with temperature following activation-type temperature dependence throughout the measured temperature region. Due to excellent material stability at the high temperature, the mobility values are precisely reproduced after the heat cycles.
Optical and magneto-optical properties of AuMnSn
Authors: Lee S. J. , Janssen Y. , Park J. M. , Cho B. K.
Published: March 2006

We have measured room-temperature magneto-optical properties of AuMnSn on a single-crystalline sample. The maximum polar Kerr rotation was predicted to be very large, about −0.7° at 1.2eV [L. Offernes, P. Ravindran, and A. Kjekshus, Appl. Phys. Lett. 82, 2862 (2003)]. We found the experimental maximum Kerr rotation and ellipticity were about three times smaller than predicted and appeared at energies about 0.6eV higher than predicted, which is possibly due to inaccurate handling of the theory based on the local spin-density approximation to density-function theory for the localized 4d and 5d orbitals in AuMnSn.
Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical vapor deposition
Authors: Bhatta R. P , Thoms B. D , Alevli M. , Woods V. , Dietz N.
Published: March 2006

The structure and surface bonding configuration of InN layers grown by high-pressure chemical vapor deposition have been studied. Atomic hydrogen cleaning produced a contamination free surface. Low-energy electron diffraction yielded a 1×1 hexagonal pattern demonstrating a well-ordered c-plane surface. High-resolution electron energy loss spectra exhibited a Fuchs–Kliewer surface phonon and modes assigned to a surface N–H species. Assignments were confirmed by observation of isotopic shifts following atomic deuterium cleaning. No In–H species were observed, and since an N–H termination of the surface was observed, N-polarity indium nitride is indicated.
Temperature dependence of point contact friction on silicon
Authors: Schirmeisen André , Jansen Lars , Hölscher Hendrik , Fuchs Harald
Published: March 2006

Point contact friction and adhesion between a silicon tip and an untreated silicon(111) wafer are measured as a function of sample temperature in ultrahigh vacuum by friction force microscopy. While the friction coefficient changes drastically in the temperature range from 50K to room temperature, and shows a reproducible maximum near 100K, the simultaneously recorded adhesion shows much less temperature dependence. Interestingly, the velocity dependence of friction shows a logarithmic increase below 150K although it is nearly constant above 150K. This peculiar behavior has profound consequences for tribological properties of devices manufactured from silicon.
Local indentation modulus characterization of diamondlike carbon films by atomic force acoustic microscopy two contact resonance frequencies imaging technique
Authors: Passeri D. , Bettucci A. , Germano M. , Rossi M. , Alippi A. , Sessa V. , Fiori A. , Tamburri E. , Terranova M. L.
Published: March 2006

Two contact resonance frequencies atomic force acoustic microscopy imaging technique has been used to evaluate local indentation modulus of a diamondlike carbon film deposited on a molybdenum foil by laser ablation from glassy carbon target. Acoustic images were obtained by measuring both first and second contact resonance frequency at each point of the scanned area, and then numerically evaluating local contact stiffness and reconstructing an indentation modulus bidimensional pattern. The wide difference of the indentation modulus values allows to detect the presence of residual glassy carbon agglomerates in the diamondlike carbon film.
Subnanometer-resolved measurement of the tunneling effective mass using bulk plasmons
Authors: Stolojan V. , Moreau P. , Goringe M. J. , Silva S. R. P.
Published: March 2006

Superlattices are periodic structures where the constituents alternate between low- and high-bandgap materials; the resulting quantum confinement tailors the resulting device properties and increases their operating speed. Amorphous carbon is an excellent candidate for both the well and barrier layers of the superlattices, leading to a fast and reliable device manufacturing process. We show theoretically and experimentally that, using low energy-loss spatially resolved spectroscopy, we can characterize the component layers of a superlattice. We measure quantum confinement of the electron wave function in the superlattice’s wells and calculate the effective tunneling mass for amorphous carbon superlattices as m*=0.067me. This effective mass makes diamondlike carbon films as feasible candidate for electronic devices.
Water-based compound Taylor cones held in vacuum: Feasibility and application to colloidal propulsion
Authors: Castro S. , Bocanegra R.
Published: March 2006

We prove here, the feasibility of water-based compound Taylor cones held in a vacuum. Unlike other solvents used in colloidal propulsion, water presents excellent qualities in terms of ion evaporation delay or attainable conductivity, enabling higher specific impulses and propulsion efficiency. However, its high volatility is limiting its use. This technique opens the path for water to be used as propellant in colloidal propulsion.
Formation of copper clusters on a thiophene mediated Si(111)-(7×7) surface via molecular anchors
Authors: Zhang Y. P. , Yong K. S. , Chan H. S. O. , Xu G. Q. , Wang X. S.
Published: March 2006

Thiophene selectively binds to the pair of adjacent Si adatom and Si rest atom on the Si(111)-(7×7) surface, leading to the covalent attachment of C–S–C linkages onto the surface. Cu atoms are found to preferentially adsorb onto the S atoms of the functional C–S–C groups in the formation of copper nanoclusters on the thiophene-mediated Si(111)-(7×7) surface.
Aβ-induced meningoencephalitis is IFN-γ-dependent and is associated with T cell-dependent clearance of Aβ in a mouse model of Alzheimer's disease
Authors: Monsonego Alon , Imitola Jaime , Petrovic Sanja , Zota Victor , Nemirovsky Anna , Baron Rona , Fisher Yair , Owens Trevor , Weiner Howard L.
Published: March 2006

Vaccination against amyloid β-peptide (Aβ) has been shown to be successful in reducing Aβ burden and neurotoxicity in mouse models of Alzheimer's disease (AD). However, although Aβ immunization did not show T cell infiltrates in the brain of these mice, an Aβ vaccination trial resulted in meningoencephalitis in 6% of patients with AD. Here, we explore the characteristics and specificity of Aβ-induced, T cell-mediated encephalitis in a mouse model of the disease. We demonstrate that a strong Aβ-specific T cell response is critically dependent on the immunizing T cell epitope and that epitopes differ depending on MHC genetic background. Moreover, we show that a single immunization with the dominant T cell epitope Aβ10–24 induced transient meningoencephalitis only in amyloid precursor protein (APP)-transgenic (Tg) mice expressing limited amounts of IFN-γ under an myelin basic protein (MBP) promoter. Furthermore, immune infiltrates were targeted primarily to sites of Aβ plaques in the brain and were associated with clearance of Aβ. Immune infiltrates were not targeted to the spinal cord, consistent with what was observed in AD patients vaccinated with Aβ. Using primary cultures of microglia, we show that IFN-γ enhanced clearance of Aβ, microglia, and T cell motility, and microglia-T cell immunological synapse formation. Our study demonstrates that limited expression of IFN-γ in the brain, as observed during normal brain aging, is essential to promote T cell-mediated immune infiltrates after Aβ immunization and provides a model to investigate both the beneficial and detrimental effects of Aβ-specific T cells.
Pertactin β-helix folding mechanism suggests common themes for the secretion and folding of autotransporter proteins
Authors: Junker Mirco , Schuster Christopher C. , McDonnell Andrew V. , Sorg Kelli A. , Finn Mary C. , Berger Bonnie , Clark Patricia L.
Published: March 2006

Many virulence factors secreted from pathogenic Gram-negative bacteria are autotransporter proteins. The final step of autotransporter secretion is C → N-terminal threading of the passenger domain through the outer membrane (OM), mediated by a cotranslated C-terminal porin domain. The native structure is formed only after this final secretion step, which requires neither ATP nor a proton gradient. Sequence analysis reveals that, despite size, sequence, and functional diversity among autotransporter passenger domains, >97% are predicted to form parallel β-helices, indicating this structural topology may be important for secretion. We report the folding behavior of pertactin, an autotransporter passenger domain from
Bordetella pertussis
. The pertactin β-helix folds reversibly in isolation, but folding is much slower than expected based on size and native-state topology. Surprisingly, pertactin is not prone to aggregation during folding, even though folding is extremely slow. Interestingly, equilibrium denaturation results in the formation of a partially folded structure, a stable core comprising the C-terminal half of the protein. Examination of the pertactin crystal structure does not reveal any obvious reason for the enhanced stability of the C terminus.
In vivo
, slow folding would prevent premature folding of the passenger domain in the periplasm, before OM secretion. Moreover, the extra stability of the C-terminal rungs of the β-helix might serve as a template for the formation of native protein during OM secretion; hence, vectorial folding of the β-helix could contribute to the energy-independent translocation mechanism. Coupled with the sequence analysis, the results presented here suggest a general mechanism for autotransporter secretion.
A structural role for ATP in the formation and stability of the human origin recognition complex
Authors: Ranjan Anand , Gossen Manfred
Published: March 2006

The locally restricted recruitment of the multisubunit origin recognition complex (ORC) to eukaryotic chromosomes defines the position of origins of DNA replication. In budding yeast and metazoans the DNA binding activity of ORC is stimulated by ATP and requires an AAA+-type nucleotide binding domain in the largest subunit. Little else is known about the mechanisms behind the ATP requirement for ORC in its initiator function and, specifically, the relevance of nucleotide binding domains present on other subunits. Here we show that ATP is required for specific subunit interactions in the human ORC, with the Orc4 subunit playing a critical role in this dynamic process. ATP is essential for the maintenance of ORC integrity and facilitates complex formation. Thus, besides its previously identified role in DNA binding, ATP serves also as a structural cofactor for human ORC.
The laterodorsal tegmentum is essential for burst firing of ventral tegmental area dopamine neurons
Authors: Lodge D. J. , Grace A. A.
Published: March 2006

In response to behaviorally salient stimuli, dopamine (DA) neurons fire in bursts. Burst firing induces a large transient increase in synaptic DA and is regarded as the functionally relevant mode of transmission that signals reward and modulates goal-directed behavior. DA neuron burst firing is dynamically regulated by afferent inputs, and it is not present
in vitro
because of severing of afferent processes. However, what afferents are requisite for burst firing
in vivo
is not known. Here, we show that tonic input from the laterodorsal tegmental nucleus (LDTg) is required for glutamate-elicited burst firing in ventral tegmental area DA neurons of anesthetized rats. Also, after LDTg inactivation, DA neurons fire as they do
in vitro
(i.e., as pacemakers); even direct glutamate application fails to cause them to burst fire under these conditions. These data show that the LDTg is critical to normal DA function, and thus, pathology within this region may lead to aberrant DA signaling.
Properties of human connexin 31, which is implicated in hereditary dermatological disease and deafness
Authors: Abrams Charles K. , Freidin Mona M. , Verselis Vytas K. , Bargiello Thaddeus A. , Kelsell David P. , Richard Gabriele , Bennett Michael V. L. , Bukauskas Feliksas F.
Published: March 2006

The connexins are a family of at least 20 homologous proteins in humans that form aqueous channels connecting the interiors of coupled cells and mediating electrical and chemical communication. Mutations in the gene for human connexin 31 (hCx31) are associated with disorders of the skin and auditory system. Alterations in functional properties of Cx31 junctions are likely to play a role in these diseases; nonetheless, little is known about the properties of the wild-type channels. Here we show that hCx31 channels, like other connexin channels, are gated by voltage and close at low pH and when exposed to long-chain alkanols. Single-channel conductance of the fully open channel is ≈85 pS, and it is permeable to Lucifer yellow, Alexa Fluor
350
, ethidium bromide, and DAPI, which have valences of −2, −1, +1, and +2, respectively. In contrast to what has been reported for mouse Cx31, hCx31 appears to form functional heterotypic channels with all four connexins tested, Cx26, Cx30, Cx32, and Cx45. These findings provide an important first step in evaluating the pathogenesis of inherited human diseases associated with mutations in the gene for Cx31.
Rac GTPase signaling through the PP5 protein phosphatase
Authors: Gentile Saverio , Darden Thomas , Erxleben Christian , Romeo Charles , Russo Angela , Martin Negin , Rossie Sandra , Armstrong David L.
Published: March 2006

We have investigated the Rac-dependent mechanism of KCNH2 channel stimulation by thyroid hormone in a rat pituitary cell line, GH
4
C
1
, with the patch-clamp technique. Here we present physiological evidence for the protein serine/threonine phosphatase, PP5, as an effector of Rac GTPase signaling. We also propose and test a specific molecular mechanism for PP5 stimulation by Rac-GTP. Inhibition of PP5 with the microbial toxin, okadaic acid, blocked channel stimulation by thyroid hormone and by Rac, but signaling was restored by expression of a toxin-insensitive mutant of PP5, Y451A, which we engineered. PP5 is unique among protein phosphatases in that it contains an N-terminal regulatory domain with three tetratricopeptide repeats (TPR) that inhibit its activity. Expression of the TPR domain coupled to GFP blocked channel stimulation by the thyroid hormone. We also show that the published structures of the PP5 TPR domain and the TPR domain of p67, the Rac-binding subunit of NADPH oxidase, superimpose over 92 α carbons. Mutation of the PP5 TPR domain at two predicted contact points with Rac-GTP prevents the TPR domain from functioning as a dominant negative and blocks the ability of Y451A to rescue signaling in the presence of okadaic acid. PP5 stimulation by Rac provides a unique molecular mechanism for the antagonism of Rho-dependent signaling through protein kinases in many cellular processes, including metastasis, immune cell chemotaxis, and neuronal development.
Proteasomal degradation of ubiquitinated Insig proteins is determined by serine residues flanking ubiquitinated lysines
Authors: Lee Joon No , Gong Yi , Zhang Xiangyu , Ye Jin
Published: March 2006

Insig-1 and Insig-2 are closely related proteins of the endoplasmic reticulum that play crucial roles in cholesterol homeostasis by inhibiting excessive cholesterol synthesis and uptake. In sterol-depleted cells Insig-1 is degraded at least 15 times more rapidly than Insig-2, owing to ubiquitination of Lys-156 and Lys-158 in Insig-1. In this study, we use domain-swapping methods to localize amino acid residues responsible for this differential degradation. In the case of Insig-2, Glu-214 stabilizes the protein by preventing ubiquitination. When Glu-214 is changed to alanine, Insig-2 becomes ubiquitinated, but it is still not degraded as rapidly as ubiquitinated Insig-1. The difference in the degradation rates is traced to two amino acids: Ser-149 in Insig-1 and Ser-106 in Insig-2. Ser-149, which lies NH
2
-terminal to the ubiquitination sites, accelerates the degradation of ubiquitinated Insig-1. Ser-106, which is COOH-terminal to the ubiquitination sites, retards the degradation of ubiquitinated Insig-2. The current studies indicate that the degradation of ubiquitinated Insigs is controlled by serine residues flanking the sites of ubiquitination.
Central muscarinic cholinergic regulation of the systemic inflammatory response during endotoxemia
Authors: Pavlov Valentin A. , Ochani Mahendar , Gallowitsch-Puerta Margot , Ochani Kanta , Huston Jared M. , Czura Christopher J. , Al-Abed Yousef , Tracey Kevin J.
Published: March 2006

TNF has a critical mediator role in inflammation and is an important therapeutic target. We recently discovered that TNF production is regulated by neural signals through the vagus nerve. Activation of this “cholinergic antiinflammatory pathway” inhibits the production of TNF and other cytokines and protects animals from the inflammatory damage caused by endotoxemia and severe sepsis. Here, we describe a role for central muscarinic acetylcholine receptors in the activation of the cholinergic antiinflammatory pathway. Central muscarinic cholinergic activation by muscarine, the M1 receptor agonist McN-A-343, and the M2 receptor antagonist methoctramine inhibited serum TNF levels significantly during endotoxemia. Centrally administered methoctramine stimulated vagus-nerve activity measured by changes in instantaneous heart-rate variability. Blockade of peripheral muscarinic receptors did not abolish antiinflammatory signaling through the vagus nerve, indicating that peripheral muscarinic receptors on immune cells are not required for the cytokine-regulating activities of the cholinergic antiinflammatory pathway. The role of central muscarinic receptors in activating the cholinergic antiinflammatory pathway is of interest for the use of centrally acting muscarinic cholinergic enhancers as antiinflammatory agents.
Expression of
Caenorhabditis elegans
neurotransmitter receptors and ion channels in
Xenopus
oocytes
Authors: Martínez-Torres Ataúlfo , Miledi Ricardo
Published: March 2006

Injection of
Caenorhabditis elegans
polyA RNA into
Xenopus laevis
oocytes led to the expression of neurotransmitter receptors that generated some unique responses, including ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors as well as receptors that coupled to G proteins, such as those to octopamine, norepinephrine, and angiotensin, which activated the oocyte’s own phosphatidylinositol system and calcium-gated chloride channels. The oocytes also expressed chloride-conducting glutamate receptors, muscarinic acetylcholine receptors, and voltage-operated calcium channels. Unexpectedly, serotonin (5-hydroxytryptamine), dopamine, GABA, and kainate did not generate ionic currents, suggesting that the corresponding receptors were not expressed or were not functional in the oocytes. The use of
X. laevis
oocytes for expressing worm RNA demonstrates that there are many molecular components whose role remains to be clarified in the nematode. Among them are the nature of the endogenous agonists for the octopamine and angiotensin receptors and the subunits that compose the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and the norepinephrine receptors that couple to the phosphoinositide cascade.
Induction of colitis causes inflammatory responses in fat depots: Evidence for substance P pathways in human mesenteric preadipocytes
Authors: Karagiannides Iordanes , Kokkotou Efi , Tansky Morris , Tchkonia Tamara , Giorgadze Nino , O'Brien Michael , Leeman Susan E. , Kirkland James L. , Pothoulakis Charalabos
Published: March 2006

Intracolonic administration of trinitrobenzene sulfonic acid in mice causes inflammation in the colon that is accompanied by increased expression of proinflammatory cytokines and of the substance P (SP), neurokinin 1 receptor (NK-1R) in the proximal mesenteric fat depot. We also investigated whether human mesenteric preadipocytes contain NK-1R and examined the functional consequences of exposure of these cells to SP as it relates to proinflammatory signaling. We found that human mesenteric preadipocytes express NK-1R both at the mRNA and protein levels. Exposure of human mesenteric preadipocytes to SP increased NK-1R mRNA and protein expression by 3-fold, and stimulated IL-8 mRNA expression and protein secretion. This effect was abolished when these cells were pretreated with the specific NK-1R antagonist CJ 012,255. Moreover, human mesenteric preadipocytes transfected with a luciferase promoter/reporter system containing the IL-8 promoter with a mutated NF-κB site lost their ability to respond to SP, indicating that SP-induced IL-8 expression is NF-κB-dependent. This report indicates that human mesenteric preadipocytes contain functional SP receptors that are linked to proinflammatory pathways, and that SP can directly increase NK-1R expression. We speculate that mesenteric fat depots may participate in intestinal inflammatory responses via SP–NK-1R-related pathways, as well as other systemic responses to the presence of an ongoing inflammation of the colon.
Role of target geometry in phagocytosis
Authors: Champion Julie A. , Mitragotri Samir
Published: March 2006

Phagocytosis is a principal component of the body’s innate immunity in which macrophages internalize targets in an actin-dependent manner. Targets vary widely in shape and size and include particles such as pathogens and senescent cells. Despite considerable progress in understanding this complicated process, the role of target geometry in phagocytosis has remained elusive. Previous studies on phagocytosis have been performed using spherical targets, thereby overlooking the role of particle shape. Using polystyrene particles of various sizes and shapes, we studied phagocytosis by alveolar macrophages. We report a surprising finding that particle shape, not size, plays a dominant role in phagocytosis. All shapes were capable of initiating phagocytosis in at least one orientation. However, the local particle shape, measured by tangent angles, at the point of initial contact dictates whether macrophages initiate phagocytosis or simply spread on particles. The local shape determines the complexity of the actin structure that must be created to initiate phagocytosis and allow the membrane to move over the particle. Failure to create the required actin structure results in simple spreading and not internalization. Particle size primarily impacts the completion of phagocytosis in cases where particle volume exceeds the cell volume.
A Computer‐Based Method for Determination of the Cell‐Free Layer Width in Microcirculation
Authors: KIM SANGHO , KONG ROBERT L. , POPEL ALEKSANDER S. , INTAGLIETTA MARCOS , JOHNSON PAUL C.
Published: March 2006

Objectives: The cell‐free layer between the erythrocyte column and the vessel wall is an important determinant of hydrodynamic resistance in microcirculatory vessels. The authors report a method for continuous measurement of the width of this layer.

Methods: The light intensity of a linear array of pixels perpendicular to the vessel axis is continuously determined from a video image of a microcirculatory vessel. A threshold level based on Otsu's method is used to establish the interface between the cell‐free layer and the erythrocyte column. To test the method, video images at 750–4500 frames/s were obtained from venules and arterioles in rat spinotrapezius muscle at normal and reduced arterial pressures before and after induction of erythrocyte aggregation with Dextran 500. The current measurements were compared to manual measurements of the same images.

Results: Values obtained by the manual and the new methods were in agreement within the 95% confidence limit by the Bland‐Altman analysis and within 90–95% range by the correlation coefficient (R2). The more frequent measurements reveal substantial, rapid variations in cell‐free layer width and changes in mean values with alteration of arterial pressure and red cell aggregability.

Conclusions: A new, computer‐based technique has been developed that provides measurements of rapid, time‐dependent variations in the width of the cell‐free layer in the microcirculation.
Clot Fragments Formed from Original Thrombus Obstruct Downstream Arteries in the Ischemic Injured Brain
Authors: WANG CHEN XU , YANG TAO , SHUAIB ASHFAQ
Published: March 2006

Objective:Embolic occlusion of the middle cerebral artery (MCA) leads to distal perfusion deficits as the vessel is recanalized. However, the mechanism for the perfusion deficits is not fully understood. The authors examined whether distal movement of fragments formed from the original thrombus contributes to the perfusion deficits.

Methods:In the first series, they studied whether the reduction in perfusion deficits is due to the dissolution of the original clots embolized or due to collateral perfusion. In the second series, they studied whether fragments formed from the original clots move to distal arterial system. In the third series, they studied whether plasmingen activator plays a role in the thrombolysis following ischemia.

Results:Occlusion of MCA permanently resulted in large perfusion deficits in the ipsilateral hemisphere, and these perfusion deficits did not change significantly after the occlusion. In contrast, perfusion deficits reduced significantly in a model of transient MCA occlusion. The numbers of fragments formed from the original clots increased gradually after the MCA occlusion in the ischemic injured brain. In addition, expression of urokinase plasminogen activator was also upregulated.

Conclusion:The present study thus reveals the mechanisms of the downstream arterial occlusion following the dissolution of original thrombus.
Dual route and connectionist models of reading: an overview
Authors: Coltheart Max
Published: March 2006

Reading researchers seek to discover exactly what kinds of information-processing activities go on in our minds when we read; to discover what the structure and organization is of the cognitive system skilled readers have acquired from learning to read. Little is known about how the
most elaborate aspects of this system work, but much has been learned about its basic building blocks such as letter identification, visual word recognition and knowledge of letter-sound rules. I contrast two approaches to theorizing about these basic reading components, the dual route approach
and the connectionist approach, and offer reasons for believing that the dual route approach is to be preferred.
Learning to read: developing processes for recognizing, understanding and pronouncing written words
Authors: Stuart Morag
Published: March 2006

Major theories of how skilled readers recognize, understand and pronounce written words include processes for phonological recoding (i.e., translating segments of print to their corresponding segments of sound) and processes by which direct access is achieved from printed words to their
meanings. If these are the processes employed in skilled reading, then these are the processes which children learning to read must develop in order to become skilled readers. This paper reviews experimental findings relevant to the development of both sets of processes in beginning and early
readers.
Genes for reading and spelling
Authors: Bates Timothy C.
Published: March 2006

This article reviews research on the behavioral and molecular genetics of reading and, where available, spelling. Recent research is summarized, suggesting that reading and spelling appear to share a common genetic basis, and that dyslexia lies on a genetic continuum with normal variance
in reading skill. Research also suggests that while many of the genes involved in reading disorder affect all forms of reading, some genes are specific for processing irregular words, while others are specific for non-word or grapheme–phoneme processing, forming a genetic basis for the
clinical distinction between surface and phonological dyslexia. Advances in molecular genetics mean that identifying specific genes for reading is now a practical project, and to date 11 chromosomal regions have been associated with reading or spelling and these findings are reviewed. Finally
data are presented on the genetic relationship of dyslexia to other developmental disorders including Autism and ADHD, and reasons for this overlap or comorbidity are discussed. Gene discovery is at a point where precise biochemical effects underlying dyslexia can be understood, findings that
will have an important impact not only for neuropsychology and neuroscience but also for psychological practice.
The dual route model and the developmental dyslexias
Authors: Castles Anne
Published: March 2006

This review discusses the important contribution made by one particular theoretical model of reading—the dual route model—to the identification and understanding of different varieties of developmental dyslexia. The model itself is first outlined, and the particular types
of reading disorder that would be predicted to occur based on this model are described. The evidence for the existence of these patterns of reading disability is then reviewed and advances that have been made in understanding their basis and aetiology are described. Finally, some suggestions
are made about how best to take research on heterogeneity in developmental dyslexia forward, moving away from distinct subtypes and more towards model-based reading profiles.
Visual factors in reading
Authors: Singleton Chris , Henderson Lisa-Marie
Published: March 2006

This article reviews current knowledge about how the visual system recognizes letters and words, and the impact on reading when parts of the visual system malfunction. The physiology of eye and brain places important constraints on how we process text, and the efficient organization
of the neurocognitive systems involved is not inherent but depends on the experience of learning to read. Although studies have reported that many children with severe reading difficulties have problems with visual fixation of words, in this context the concept of 'visual dyslexia' remains
controversial. Evidence that a significant proportion of children with dyslexia have impairment of the magnocellular component of the visual system (which responds to contrast and movement) has led to alternative theories challenging the phonological deficit model of dyslexia. Deficits in
the magno system have also been proposed to explain symptoms of visual stress that many people experience when reading, and to account for the alleviation of these symptoms by the use of coloured overlays or tinted lenses. However, a competing theory that posits cortical hypersensitivity to
pattern glare as the cause of visual stress is generally more favoured at the present time. Our scientific understanding of reading would be much improved if visual factors were better integrated into theories that currently focus almost exclusively on phonological factors, but some progress
towards this is being made.
The design of public participation in Environmental Impact Assessments
Authors: Wang Zhi-gang , Chen Xin-geng
Published: March 2006

Public participation has become an important part in the Environmental Impact Assessment process. However, a few factors can affect, even change, its positive effect, including times when the public is to be involved, and the distribution of the necessary forms to the public involved. Therefore it is very important to pay attention to those factors and to design an integrated plan for public participation in the assessment process. In this article, the legal requirements for public participation are firstly set out, then current problems as well as the gaps between the practices and regulations of participation are analyzed. The design of a plan to improve the effectiveness of the assessment process, including designing principles, defining the roles of the different actors, setting standards for selecting the form(s) to involve participation of the public, and defining the times when the public is to be involved, is discussed.
Methods for integrating environment into decision-making in China
Authors: Fang Q. H. , Hong H. S. , Zhang L. P. , Chen W. Q. , Xue X. Z.
Published: March 2006

The prevailing systems for decision-making in many countries tend to separate environmental factors at the policy, planning and management levels, a practice that has important implications for sustainable development. Among many methods, at different decision-making levels, environmental planning and environmental assessment are currently the most widely used in China. This article briefly introduces four case studies featuring environmental planning and assessment in Xiamen, a coastal city in southeast China. Differences in scope of application, timing, nature, legal status, methodologies and effectiveness are described. Six principles for the successful integration of environmental protection and development are advanced based on the analytical results. As well, a simplified integration framework is proposed.
Hydrogen production by fermentation: Review of a new approach to environmentally safe energy production
Authors: Ren N. Q. , Li Y. F. , Wang A. J. , Li J. Z. , Ding J. , Zadsar M.
Published: March 2006

As a new clean energy source, the demands for and use of hydrogen fuel are rapidly increasing. Therefore, biohydrogen production technology is being developed to reduce operation costs in many countries. Improvement of biohydrogen production capacity and cost reduction are key factors to bring about industrial implementation. One of the most effective production methods is microbiological: the use of bacteria with high hydrogen-production capacity and performance. The anaerobic process of biohydrogen production was developed in the 1990s. The isolation and identification of highly efficient biohydrogen producing anaerobic bacteria is an important foundation for the fermentative production of hydrogen by anaerobic digestion of organic wastewater.
A case study of urban environment—economic management in Xiamen, China
Authors: Yang Z. F. , Su M. R. , Xu L. Y.
Published: March 2006

Efficient urban environmental management methods are of importance, even essential to urban sustainable development. Economic methods have increasingly had advantages over other methods of environmental management during the course of the economic system's transition in China. Therefore, the establishment of an effective urban environment-economic management system is necessary and valuable. This paper primarily studies urban environment-economic management and establishes a framework for an urban environment-economic management system. As an example, we created the environment-economic management system of Xiamen, giving priority to economic methods combined with other management methods. We also investigated some problems probably arising in the application of this management system. Finally, a preliminary benefit analysis of the environment-economic management system of Xiamen was conducted. This new comprehensive framework for an environment-economic management system may be used in other cities in China and other developing countries around the world.
Evaluation of nitrogen balance on pig/crop farm systems in Jiulong River watershed, China
Authors: Zeng Yue , Hong Hua-Sheng , Cao Wen-Zhi , Chen Neng-Wang , Wang Wei-Ping , Zhang Luo-Ping
Published: March 2006

Field surplus nitrogen and farm disposal nitrogen (N) are major sources of environmental pollution in farm systems. The purpose of this study was to use nitrogen balances at the field and farm level approaches to estimate the effects of pig production in the Jiulong River watershed, Fujian province, China, on nitrogen losses to the environment on 67 pig farms. The field surplus nitrogen ranged from 6.19 to 18.19 t nitrogen ha−1, which was caused by high pig density and excessive application of manure. Manure application rates of more than 450 to 510 kg nitrogen ha −1 would increase the potential nitrate concentration to more than 10 to 20 mg l −1. Therefore, 44 to 48 heads of pig ha −1 was suggested to as the environmental capacity for sustaining optimal nitrogen cycling in pig farms in the Jiulong River watershed.

The majority of farms have potential environmental risks because of high farm nitrogen imbalances. With more than a 2:1 ratio of N inputs to outputs, N inputs were 50 percent higher than outputs. Feed was the main input source, while pig production and manure exported were the major managed outputs. Based on the farm nitrogen balance calculation, the management options that would contribute to a more favorable nitrogen balance were also identified.
Blue-green algae is predominant in Dianshan Lake
Authors: Zhang Zhihong , Qu Weidong , Jiang Songhui , Zhu Huigang
Published: March 2006

Dianshan Lake is the largest lake in the Shanghai suburbs and also one of the most important fresh water sources for Shanghai. To investigate the growth and predominant genera of algae in the lake, water samples were collected during the summer and autumn of 2002. The number of algae cells was counted, each algae genus was identified, and the percentage of each major taxa was calculated. The number of algae cells was affected with alternation of seasons and ranged between 2.27 × 106 l− 1 and 4.24 × 106 l− 1. The percentage of Cyanophyta and Chlorophyta ranged from 20 to about 73% and 21 to about 65%, respectively. The growth and population of Bacillariophyta and Euglenophyta were less than 20% during the sampling period. The change of Cyanophyta population resembled that of the total algae temporally. Cyanophyta reached 50% in the blue-green algae population; the impending water bloom posed a risk to health. Blue-green algae were the dominant algae in Dianshan Lake during the summer and autumn.
The development of HIV/AIDS interventions in Romanian prisons
Authors: Qaramah Afrodita , Parausanu Emanuel
Published: March 2006

The Romanian Prison Service Department, as part of the Ministry of Justice, comprises 42 prison institutions, including 34 prisons, six prison hospitals and three centres for young
offenders. The prison population was 46,789 in June 2003 (General Directorate of Penitentiaries, Internet Site, www.anp.ro). Harm reduction is an important area for the
Romanian Prison Service Department to consider, as statistics from the Ministry of Health and Family show that 9928 HIV and AIDS cases were recorded in the community, with
most of them being teenagers (31 December 2002). In addition, the incidence of infectious diseases generally in the prison system is high. A range of visits to other countries and discussions with staff have been undertaken to find out what models of harm reduction best fit the Romanian situation (Head of Health Care, Prison Service Department 2004). The Romanian HIV/AIDS National Strategy (2000/2003) prioritizes youth, vulnerable and disabled groups, medical assistance and support for HIV/AIDS‐infected people and epidemiological surveillance. The strategy also includes the development of harm reduction and prevention. The strategy includes
cooperation with non‐governmental organizations (NGOs) dealing with needle‐exchange and information programs and condom distribution.