bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfering with the Actin Network and Its Effect on Long-Term Potentiation and Synaptic Tagging in Hippocampal CA1 Neurons in SlicesIn Vitro
Authors: Ramachandran Binu , Frey Julietta U.
Published: September 2009

Long-term potentiation (LTP) is a cellular correlate for memory formation, which requires the dynamic changes of the actin cytoskeleton. As shown by others, the polymerization of the actin network is important for early stages of LTP. Here, we investigated the role of actin dynamics in synaptic tagging and particularly in the induction of protein synthesis-dependent late-LTP in the CA1 region in hippocampal slicesin vitro. We found that the inhibition of actin polymerization affects protein synthesis-independent early-LTP, prevents late-LTP, and interferes with synaptic tagging in apical dendrites of hippocampal CA1. The transformation of early-LTP into late-LTP was blocked by the application of the structurally different actin polymerization inhibitors latrunculin A or cytochalasin D. We suggest that the actin network is required for early “housekeeping” processes to induce and maintain early-LTP. Furthermore, inhibition of actin dynamics negatively interacts with the setting of the synaptic tagging complex. We propose actin as a further tag-specific molecule in apical CA1 dendrites where it is directly involved in the tagging/capturing machinery. Consequently, inhibition of the actin network prevents the interaction of tagging complexes with plasticity-related proteins. This results in the prevention of late-LTP by inhibition of the actin network during LTP induction.
Spared and Impaired Olfactory Abilities after Thalamic Lesions
Authors: Sela Lee , Sacher Yaron , Serfaty Corinne , Yeshurun Yaara , Soroker Nachum , Sobel Noam
Published: September 2009

Olfactory information reaches olfactory cortex without a thalamic relay. This neuroanatomical substrate has combined with functional findings to suggest that, in olfaction, the typical thalamic role in sensory processing has shifted to the olfactory bulb or olfactory cortex. With this in mind, we set out to ask whether the thalamus at all plays a significant functional role in human olfaction. We tested olfactory function in 17 patients with unilateral focal thalamic lesions and in age-matched healthy controls. We found that thalamic lesions did not significantly influence olfactory detection but significantly impaired olfactory identification, and only right lesions altered olfactory hedonics by reducing the pleasantness of pleasant odors. An auditory control revealed that this shift in pleasantness was olfactory specific. These olfactory impairments were evident in explicit measures of perception, as well as in patterns of sniffing. Whereas healthy subjects modulated their sniffs in accordance with odorant content, thalamic patients did not. We conclude that, although the thalamus is not in the path of olfactory information from periphery to cortex, it nevertheless plays a significant functional role in human olfaction.
The Role of Background Statistics in Face Adaptation
Authors: Wu Jianhua , Xu Hong , Dayan Peter , Qian Ning
Published: September 2009

Cross-adaptation is widely used to probe whether different stimuli share common neural mechanisms. For example, that adaptation to second-order stimuli usually produces little aftereffect on first-order stimuli has been interpreted as reflecting their separate processing. However, such results appear to contradict the cue-invariant responses of many visual cells. We tested the novel hypothesis that the null aftereffect arises from the large difference in the backgrounds of first- and second-order stimuli. We created second-order faces with happy and sad facial expressions specified solely by local directions of moving random dots on a static-dot background, without any luminance-defined form cues. As expected, adaptation to such a second-order face did not produce a facial-expression aftereffect on the first-order faces. However, consistent with our hypothesis, simply adding static random dots to the first-order faces to render their backgrounds more similar to that of the adapting motion face led to a significant aftereffect. This background similarity effect also occurred between different types of first-order stimuli: real-face adaptation transferred to cartoon faces only when noise with correlation statistics of real faces or natural images was added to the cartoon faces. These findings suggest the following: (1) statistical similarities between the featureless backgrounds of the adapting and test stimuli can influence aftereffects, as in contingent adaptation; (2) weak or null cross-adaptation aftereffects should be interpreted with caution; and (3) luminance- and motion-direction-defined forms, and local features and global statistics, converge in the representation of faces.
Selective Expression of ErbB4 in Interneurons, But Not Pyramidal Cells, of the Rodent Hippocampus
Authors: Vullhorst Detlef , Neddens Jörg , Karavanova Irina , Tricoire Ludovic , Petralia Ronald S. , McBain Chris J. , Buonanno Andres
Published: September 2009

NRG1andERBB4have emerged as some of the most reproducible schizophrenia risk genes. Moreover, the Neuregulin (NRG)/ErbB4 signaling pathway has been implicated in dendritic spine morphogenesis, glutamatergic synaptic plasticity, and neural network control. However, despite much attention this pathway and its effects on pyramidal cells have received recently, the presence of ErbB4 in these cells is still controversial. As knowledge of the precise locus of receptor expression is crucial to delineating the mechanisms by which NRG signaling elicits its diverse physiological effects, we have undertaken a thorough analysis of ErbB4 distribution in the CA1 area of the rodent hippocampus using newly generated rabbit monoclonal antibodies and ErbB4-mutant mice as negative controls. We detected ErbB4 immunoreactivity in GABAergic interneurons but not in pyramidal neurons, a finding that was further corroborated by the lack of ErbB4 mRNA in electrophysiologically identified pyramidal neurons as determined by single-cell reverse transcription–PCR. Contrary to some previous reports, we also did not detect processed ErbB4 fragments or nuclear ErbB4 immunoreactivity. Ultrastructural analysis in CA1 interneurons using immunoelectron microscopy revealed abundant ErbB4 expression in the somatodendritic compartment in which it accumulates at, and adjacent to, glutamatergic postsynaptic sites. In contrast, we found no evidence for presynaptic expression in cultured GAD67-positive hippocampal interneurons and in CA1 basket cell terminals. Our findings identify ErbB4-expressing interneurons, but not pyramidal neurons, as a primary target of NRG signaling in the hippocampus and, furthermore, implicate ErbB4 as a selective marker for glutamatergic synapses on inhibitory interneurons.
Dynamic Computation of Incentive Salience: “Wanting” What Was Never “Liked”
Authors: Tindell Amy J. , Smith Kyle S. , Berridge Kent C. , Aldridge J. Wayne
Published: September 2009

Pavlovian cues for rewards become endowed with incentive salience, guiding “wanting” to their learned reward. Usually, cues are “wanted” only if their rewards have ever been “liked,” but here we show that mesocorticolimbic systems can recompute “wanting”de novoby integrating novel physiological signals with a cue's preexisting associations to an outcome that lacked hedonic value. That is, a cue's incentive salience can be recomputed adaptively. We demonstrate that this recomputation is encoded in neural signals coursing through the ventral pallidum. Ventral pallidum neurons do not ordinarily fire vigorously to a cue that predicts the previously “disliked” taste of intense salt, although they do fire to a cue that predicts the taste of previously “liked” sucrose. Yet we show that neural firing rises dramatically to the salt cue immediately and selectively when that cue is encountered in a never-before-experienced state of physiological salt depletion. Crucially, robust neural firing to the salt cue occurred the first time it was encountered in the new depletion state (in cue-only extinction trials), even before its associated intense saltiness has ever been tasted as positively “liked” (salt taste had always been “disliked” before). The amplification of incentive salience did not require additional learning about the cue or the newly positive salt taste. Thus dynamic recomputation of cue-triggered “wanting” signals can occur in real time at the moment of cue re-encounter by combining previously learned Pavlovian associations with novel physiological information about a current state of specific appetite.
Development of a Patient-Reported Outcome Measure for Children With Streptococcal Pharyngitis
Authors: Shaikh Nader , Martin Judith M. , Casey Janet R. , Pichichero Michael E. , Wald Ellen R. , Colborn D. Kathleen , Gerber Michael A. , Kearney Diana H. , Balentine Tracy L. , Haralam Mary Ann , Hoberman Alejandro
Published: September 2009

OBJECTIVE: The objective of this study was to develop a patient-reported outcome measure (Strep-PRO) for assessing symptoms of group A Streptococcus (GAS) pharyngitis from the child's point of view and to present preliminary data on its internal reliability, construct validity, and responsiveness.

METHODS: We selected 8 symptoms for inclusion in the Strep-PRO. We used the Strep-PRO to assess improvement in children who were aged 5 to 15 years and had confirmed GAS pharyngitis. Children completed the scale at study visits and as a diary at home. To evaluate internal reliability, we examined correlations between the items on the scale. To evaluate construct validity, we examined the correlation at entry between Strep-PRO scores and scores on other, previously validated measures of pain and functional status. To evaluate responsiveness, we examined the change in score from enrollment to follow-up. The correlation between the Strep-PRO score and parental assessment of symptoms was also evaluated.

RESULTS: A total of 131 children were enrolled; 113 returned completed diaries. The internal reliability of the scale was high. The magnitude of correlations between Strep-PRO scores and other measures of pain and functional status ranged from 0.39 to 0.63. The responsiveness of the Strep-PRO was very good. The overall level of agreement between child Strep-PRO scores and parental assessment of symptoms was 0.57.

CONCLUSIONS: The scale seems to measure effectively both pain and overall functional status in children with GAS pharyngitis. These data support the use of Strep-PRO as a measure of outcome in future clinical trials.
An invariant theorem in duality
Authors: Yang Yunyan , Li Ronglu
Published: September 2009

The concept of absolute convergence for series is generalized to locally convex spaces and an invariant theorem for absolutely convergent series in duality is established: when a locally convex space
X
is weakly sequentially complete, an admissible topology which is strictly stronger than the weak topology on
X
in the dual pair (
X,X′
) is given such that it has the same absolutely convergent series as the weak topology in
X
.
On some rate of convergence questions
Authors: Tuyen Dao
Published: September 2009

This paper gives answers to some questions posed in Hanson and Wright,
Z. Wahrscheinlichkeitstheor. Verw. Geb.
,
19
(1971), on rates of convergence in probability to zero for weighted sums of independent random variables.
Ideal clones: Solution to a problem of Czédli and Heindorf
Authors: Goldstern Martin , Pinsker Michael
Published: September 2009

Given an infinite set X and an ideal I of subsets of X, the set of all finitary operations on X which map all (powers of) I-small sets to I-small sets is a clone. In [2], G. Czédli and L. Heindorf asked whether or not for two particular ideals I and J on a countably infinite set X, the corresponding ideal clones were a covering in the lattice of clones. We give an affirmative answer to this question.
Excellent extensions and Gorenstein homological dimensions
Authors: Gu Qinqin , Zhu Xiaosheng
Published: September 2009

Let R be a ring and S an excellent extension of R. In this paper we study the Gorenstein homological dimensions over R and S. We show that if M is an S-module, then MR is Gorenstein projective if and only if MS is Gorenstein projective. Secondly, we prove that the right Gorenstein dimension of R is equal to the right Gorenstein dimension of S. Some results in [4] and [6] are extended to the settings of Gorenstein projective modules and Gorenstein projective dimensions, respectively.
In situ monitoring of cracking behaviors of plasma-sprayed coatings by the laser acoustic emission technique
Authors: Taniguchi Koichi , Enoki Manabu , Watanabe Makoto , Kuroda Seiji , Ito Kaita
Published: September 2009

Multichannel acoustic emission (AE) measurements by four laser interferometers were developed and applied during a plasma-spray coating process that is known as being a high-temperature process and an extremely noisy environment in both mechanical and electrical domains. The AE signals could be successfully detected during the cooling period after the deposition, and it was clearly indicated that a higher preheating temperature resulted in the improvement of bonding between splats and/or at the interface of the coating and the substrate. The maximum principal stress generated during the deposition process was calculated by the transient heat and stress analysis and the obtained AE events. The critical stress for crack initiation of the alumina coating on a steel substrate with an NiCr bond coat layer was estimated as 30∼45 MPa. The developed techniques were shown to be a potential tool for in situ monitoring of the thermal spray process, by which an increase in the reliability of thermal spray coatings can be expected.
Obtaining shear relaxation modulus and creep compliance of linear viscoelastic materials from instrumented indentation using axisymmetric indenters of power-law profiles
Authors: Cheng Yang-Tse , Yang Fuqian
Published: September 2009

Using Laplace transform, we solve the inverse problem of obtaining the shear relaxation modulus and creep compliance of linear viscoelastic solids from indentation by axisymmetric indenters of power-law profiles. We identify several simple, though nontrivial, loading paths for carrying out indentation measurements such that the inverse problem has analytical solutions. We show that the shear relaxation modulus and creep compliance may be readily obtained using the newly derived analytical expressions together with proposed indentation loading paths.
Analytical solution for the Kissinger equation
Authors: Roura Pere , Farjas Jordi
Published: September 2009

An analytical solution for the Kissinger equation relating the activation energy, E, with the peak temperature of the reaction rate, Tm, has been found. It is accurate (relative error below 2%) for a large range of E/RTm values (from 15 to above 60) that cover most experimental situations. The possibilities opened by this solution are outlined by applying it to the analysis of some particular problems encountered in structural relaxation of amorphous materials and in kinetic analysis.
Electronic transport through crossed conducting polymer nanowires
Authors: Long Yun-Ze , Duvail Jean-Luc , Wang Qing-Tao , Li Meng-Meng , Gu Chang-Zhi
Published: September 2009

In order to study the electronic properties of conjugated polymer nanowire junctions, we have fabricated two devices consisting of two crossed poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires with platinum microleads attached to each end of each nanowire. We find that the junction resistance of the crossed nanowires is much larger than the intrinsic resistance of the individual PEDOT nanowire, and increases with decreasing temperature, which can be described by a thermal fluctuation-induced tunneling conduction model. In addition, the crossed junctions show linear current-voltage characteristics at room temperature.
Influence of casting temperature on microstructures and mechanical properties of Cu50Zr45.5Ti2.5Y2 metallic glass prepared using copper mold casting
Authors: Zhu Zhengwang , Zhang Haifeng , Wang Hao , Ding Bingzhe , Hu Zhuang-Qi , Huang Han
Published: September 2009

The influence of casting temperatures on microstructures and mechanical properties of rapidly solidified Cu50Zr45.5Ti2.5Y2 alloy was investigated. With increasing casting temperatures, the amount of the crystalline phase decreases. At a high casting temperature, i.e., 1723 K, glass-forming ability (GFA) of the present alloy is enhanced. The results imply that adjusting the casting temperature could be used for designing the microstructures of bulk metallic glass matrix composite. Nanoindentation tests indicated that CuZr phases are slightly softer and can accommodate more plastic deformation than the amorphous matrix. Compression tests confirmed that this kind of second phase (CuZr) precipitated under lower casting temperatures helps to initiate multiple shear bands, resulting in a great improvement in mechanical properties of the samples. Our work indicates that casting temperatures have a great influence on GFA, microstructures, and mechanical properties of the rapidly solidified alloy, therefore controlling the casting temperature is crucial to the production of BMGs.
First-principles study of oxygen incorporation and migration mechanisms in Ti2AlC
Authors: Liao Ting , Wang Jingyang , Li Meishuan , Zhou Yanchun
Published: September 2009

We performed density-functional calculations of oxygen incorporation and diffusion in layered Ti2AlC for a range of intrinsic- and impurity-element chemical potentials. In view of the thermal equilibrium coexistence between oxygen-dissolved Ti2AlC and the oxide scale, a thermodynamic scheme is presented that allows the comparison of the relative stability of oxygen defects in different exterior environments. The calculations show that the oxygen atom favors substitution on carbon lattice sites (OC) under oxygen-lean conditions and high temperatures, whereas the occurrence of an oxygen interstitial in the aluminum atomic layer (IO-tri) becomes more preferential in an oxygen-rich atmosphere and low temperatures. Interstitial oxygen (IO-tri) diffusion via a metastable interstitial site (IO-oct) has a comparatively low migration energy. The substitutional oxygen defect (OC) diffuses by exchanging with neighboring carbon vacancy, which needs a relatively high diffusion barrier.
Microstructural characterization and crystallization kinetics of (1-x)TeO2-0.10CdF2-xPbF2 (x = 0.05, 0.10, and 0.15 mol) glasses
Authors: Tatar Demet , Lutfi Öveçoğlu M. , Özen Gonul , Speakman Scott A.
Published: September 2009

Microstructural characterization and crystallization kinetics of (1-x)TeO2-0.10CdF2-xPbF2 (x = 0.05, 0.10, and 0.15 in molar ratio) glasses were investigated using differential thermal analysis (DTA), x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy/energy dispersive spectrometer (SEM/EDS), and absorbance spectroscopy techniques. For all of the glass compositions only one exothermic peak was observed on the DTA plots, and on the basis of the XRD and Raman spectrophotometry investigations it was understood that they refer to the formation of the α-TeO2 phase. SEM/EDS investigations revealed the presence of oriented needle-like α-TeO2 crystals in the 0.85TeO2-0.10CdF2-0.05PbF2 glass, rectangle-shaped α-TeO2 crystals in the 0.80TeO2-0.10CdF2-0.10PbF2 glass, and disoriented needle-like crystals in the 0.75TeO2-0.10CdF2-0.15PbF2 glass. DTA analyses were carried out at different heating rates, and the Avrami constants for all of the glasses were approximately 1. The activation energy calculations and SEM investigations demonstrated that the formation of the crystalline phases occurred via surface crystallization mechanism for all of the glasses. Activation energies for crystallization in these glasses were determined from the modified Kissinger plots and were found to vary between 67 and 183 kJ/mol. The addition of PbF2 as a network modifier into the glass structure contributes to the intensity of the Raman peaks change and forced the transition of the glass network from TeO4 trigonal bipyramid units to the TeO3 trigonal pyramid structural units.
YVO4: RE3+(RE = Eu, Sm, Dy, Er) nanophosphors: Facile hydrothermal synthesis, microstructure, and photoluminescence
Authors: Yan Bing , Wu Jianhua
Published: September 2009

YVO4: 10%RE3+(RE = Eu, Sm, Dy, Er) nanophosphors have been synthesized by a facile modified hydrothermal technology to obtain the high purity. The key procedure for this hydrothermal process is the adding order of precursors, in which excess sodium vanadate should be added in the solution of rare earth nitrates. The microstructure (crystal phase, morphology, particle size) of these phosphors are characterized by x-ray powder diffraction, scanning electron microscope, and transmission electron microscope, which indicates that there are some cube-like crystals with tetragonal zircon structure and the average particle size is approximately 40 nm. The luminescent behaviors for the four rare earth ion-activated YVO4nanophosphors have been studied, and, for YVO4: 10%Eu3+nanophosphors in particular, it is found that a different hydrothermal process influences the phase composition, microstructure, and photoluminescence. This result suggests that the hydrothermal synthesis process (by adding sodium vanadate to the solution of rare earth nitrates) is favorable for YVO4nanophosphor to obtain pure phase, small particle size, long luminescent lifetime, and high luminescence quantum efficiency.
Influence of flow ratio of N2 to (N2+Ar) mixture on the structure and properties of zirconium nitride films prepared by radio frequency magnetron sputtering
Authors: Sui Yingrui , Liu Jiukai , Liu Bo , Wang Lihong , Yao B.
Published: September 2009

Zr–N films were grown on glass and Si (100) substrate by radio-frequency magnetron sputtering using a mixture of high pure nitrogen and argon as sputtering gases. The structure and properties of Zr–N compounds in the films change with N2/(N2+Ar) flow ratio (RN2). At low RN2, a ZrN alloy with the rocksalt structure (denoted as γ-ZrNx) is formed. The N concentration x and lattice constant increases with increasing RN2, and x reaches 1 when the RN2 goes up to 20%. As the RN2 exceeds 20%, the film is composed of γ-ZrN and Zr3N4 phase with Th3P4 structure (denoted as c-Zr3N4). The relative content decreases for the γ-ZrN but increases for the c-Zr3N4 with increasing RN2, and a single phase of c-Zr3N4 was deposited on glass at RN2 of 100%. The c-Zr3N4 behaves with p-type conductivity with a band gap of 2.8 eV. The lattice constant of the c-Zr3N4 was measured to be ∼0.674 nm. The mechanism of the phase transition from γ-ZrN to c-Zr3N4 with increasing RN2 was suggested.
Scale-dependent nanomechanical behavior and anisotropic friction of nanotextured silicon surfaces
Authors: Zhang Hanshen , Komvopoulos Kyriakos
Published: September 2009

Nanoscale surface texturing of silicon was accomplished by oblique Ar+ ion beam irradiation. Atomic force microscope (AFM) imaging showed that nanotexturing produced an anisotropic morphology consisting of ordered nanometer-sized ripples. Surface force microscope (SFM) measurements showed that the nanotextured surface exhibited scale-dependent nanomechanical behavior during indentation loading/unloading and anisotropic sliding friction, significantly different from those of the original (untextured) surface. AFM and SFM results showed a strong dependence of the nanoindentation response and friction coefficient on the tip radius and sliding direction relative to the ripple orientation. The observed experimental trends are interpreted in terms of the applied normal load, real contact area, interfacial adhesion force, tip-ripple interaction scale, and ripple orientation.
Energy transfer in a ternary system composed of Tb(DBM)3Phen, Eu(DBM)3Phen, and poly(N-vinylcarbazole)
Authors: Luo Yanhua , Yu Xiaowu , Su Wei , Zhang Zhoushun , Wu Wenxuan , Yan Qing , Zhang Qijin
Published: September 2009

A ternary system composed of Tb(DBM)3Phen (TbDP), Eu(DBM)3Phen (EuDP), and poly(N-vinylcarbazole) (PVK) was prepared with good thermal stability and the photoluminescence (PL) was studied. By comparing their emissions, it was found that energy transfer exists from PVK to lanthanide complexes in the ternary system. It also was found that the lifetime of 5D0 of Eu3+ in the ternary system is longer than that of the binary system of EuDP and PVK, but the lifetime of 5D4 of Tb3+ in the ternary system is shorter than that of the binary system of TbDP and PVK, showing evidence of energy transfer from TbDP to EuDP. Temperature-dependent PL spectra of the ternary system from 9 to 300 K further showed there is a change in energy transfer efficiencies from Tb3+ ions to Eu3+ ions at different temperature ranges, which not only is more evidence of energy transfer but also can be used as a temperature detector or a thermal-sensitive probe of a optical fiber sensor.
Secondary ion mass spectrometry study of Ti4+diffusion properties in congruent Er:LiNbO3codoped with moderate concentration of MgO
Authors: Zhang De-Long , Chen Bei , Sun Liang , Xu Yu-Heng , Pun Edwin Yue-Bun
Published: September 2009

At 1100 °C, the diffusion properties of Ti4+into congruent LiNbO3crystals codoped with 0.5 mol% Er2O3and different MgO concentrations of 0.5, 1.0, and 1.5 mol% have been studied by secondary ion mass spectrometry (SIMS). ThreeY-cut and threeZ-cut plates with different Mg doping levels were coated with a 60-nm-thick Ti film at first and then annealed at 1100 °C for 28 h in a wet O2atmosphere. SIMS was used to analyze depth profile characteristics of diffused Ti ions and the constituent elements of the substrate as well. The results show that the diffusion reservoir was exhausted and the Ti metal film was completely diffused. All measured Ti profiles follow a Gaussian function. No Mg out-diffusion accompanied the Ti in-diffusion procedure for all crystals studied. The 1/ediffusion depth is similar to 8.3/10.2, 7.4/8.7, and 6.6/8.2 ± 0.2/0.2 μm/μm for theY/Z-cut crystal with the Mg doping level of 0.5, 1.0, and 1.5 mol%, respectively, yielding a Ti4+diffusivity of 0.62/0.93, 0.49/0.67, and 0.39/0.60 ± 0.03/0.03 (μm2/h)/(μm2/h), respectively. The diffusion shows definite anisotropy and a considerable MgO doping level effect. Under the same Mg doping level, the diffusion in aZ-cut crystal is faster. The diffusivity decreases with the increase of the Mg doping level. This effect is qualitatively explained from the viewpoint of the Mg doping effect on concentration of the intrinsic defects in LiNbO3crystal.
Homogeneity of the superplastic Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass
Authors: Chen Lian-Yi , Zeng Yuewu , Cao Qing-Ping , Park Byung-Joo , Chen Yimeng , Hono Kazuhiro , Vainio Ulla , Zhang Zao-Li , Kaiser Ute , Wang Xiao-Dong , Jiang Jian-Zhong
Published: September 2009

A recent report on the “room temperature superplasticity” in the Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass [Y.H. Liu et al., Science315, 1385 (2007)] was ascribed to the distinctive micrometer-sized structural heterogeneity. To verify the microstructure in this alloy, transmission electron microscopy (TEM) and anomalous small-angle x-ray scattering experiments were conducted. The results show that no micrometer-sized or nanometer-sized structural heterogeneities can be found. The micrometer-sized dark and bright regions that were previously reported as the reason for the plasticity are artifacts caused by TEM specimen preparation, rather than the intrinsic structure feature of this alloy. This finding is important for further studying the unique properties of this alloy.
Effect of Saquinavir‐Ritonavir on Cytochrome P450 3A4 Activity in Healthy Volunteers Using Midazolam as a Probe
Authors: Schmitt Christophe , Hofmann Carsten , Riek Myriam , Zwanziger Elke , Patel Arpna
Published: September 2009

Study Objective. To investigate the inhibitory potential of multiple doses of ritonavir‐boosted saquinavir on the pharmacokinetics of oral midazolam, a cytochrome P450 (CYP) 3A4 model substrate.

Design. Prospective, open‐label, one‐sequence, two‐period crossover study.

Setting. Clinical pharmacology unit in the United Kingdom.

Participants. Eighteen healthy adult male and female volunteers (median age 37.5 yrs).

Intervention. A single oral dose of midazolam 7.5 mg was administered on day 1. A second dose was administered on day 16, after 14 days of oral saquinavir 1000 mg‐ritonavir 100 mg twice/day.

Measurements and Main Results. Serial blood samples were taken for measurement of plasma concentrations of midazolam and its metabolite, 1′‐hydroxymidazolam. Pharmacokinetic parameters of midazolam and 1′‐hydroxymidazolam were determined when midazolam was given alone (day 1) and after coadministration with saquinavir‐ritonavir for 14 days (day 16). Two weeks of treatment with saquinavir‐ritonavir resulted in a 4.3‐fold increase in maximum plasma concentration (Cmax) and a 12.4‐fold increase in the area under the plasma concentration‐time curve from time zero extrapolated to infinity (AUC0‐∞) for midazolam. Midazolam's half‐life increased from 4.7 to 14.9 hours. Concomitant reductions for 1′‐hydroxymidazolam were approximately 7‐fold for Cmaxand 2‐fold for AUC0‐∞. The 1′‐hydroxymidazolam AUC0‐∞:midazolam AUC0‐∞ratio was only 1% during coadministration of midazolam with saquinavir‐ritonavir compared with 33% for midazolam alone. Adverse‐event reports indicated that the combination of saquinavir, ritonavir, and midazolam was well tolerated but resulted in prolonged sedation.

Conclusion. Administration of ritonavir‐boosted saquinavir markedly increased the exposure of midazolam by inhibiting its metabolism, confirming that the combination of saquinavir and ritonavir at steady state strongly inhibits CYP3A4 activity.
Textmasters: Bringing Literature Circles to Textbook Reading Across the Curriculum
Authors: Wilfong Lori G.
Published: September 2009

A fifth‐grade science teacher and university researcher challenged the notion that textbook reading follows the same archaic formula: read the textbook and answer the questions at the end of the section. Together, they adapted literature circle roles to fit textbook structures, resulting in the strategy they call Textmasters. This article describes the strategy, along with the action research project that proves its efficacy in the content area middle school classroom.

تلخيص البحث: لقد تحدى معلم صف خامس علمي وباحث جامعي المفهوم بأن قراءة كتابة الصف تتبع نفس المعادلة القديمة: إقرأ الكتاب وأجب عن الأسئلة في نهاية القسم. وكيفا المعلمان أدوار حلقات أدبية لتناسب تراكيب كتابة الصف الأمر الذي أدى إلى إستراتيجية تمت تسميتها بـ((تكست ماسترز)) أي خبراء النصوص. إذ تصف هذه المقالة الإستراتيجية علاوة على مشروع البحث المنشط الذي يثبت فعاليته في سياق مجال المحتوى في صفوف المدرسة الإعدادية.

一位任教小学五年级科学科的教师与一位大学研究员，质疑课本阅读教学遵循同一陈旧公式这观念：首先阅读课本，然后回答章节末尾的问题。他们为切合课本结构所需，参照进行文学圈教学法时学生所分担的任务，一起编成了他们称之为「科学科文本阅读讨论主持人」这阅读教学策略。本文旨在描述该教学策略，并报告一项行动研究，以验证该教学策略在中学学科内容教室里所产生的效能。

Un professeur de sciences de cinquième année et un chercheur à l'université ont fait le pari que la lecture des livres de textes choisis suit une même formule archaïque: lire le manuel et répondre aux questions à la fin du passage. Ensemble, ils ont adapté les rôles des cercles de lecture pour s'ajuster à la structure du manuel, d'où a résulté une stratégie qu'ils ont appelé les maîtres textes. Cet article décrit cette stratégie, ainsi qu'un projet de recherche action qui met en évidence son efficacité pour les disciplines enseignées au collège.

Учитель естествознания, работающий с пятиклассниками, и ученый, работающий в университете, бросили вызов многовековому алгоритму: “прочитай учебник и ответь на вопросы по прочитанному”. Их ученики начали читать предметные тексты так, как это обычно делается в литературных кружках, и в результате возникла стратегия под названием “текст‐мастер”. B статье разъясняется сама стратегия и описано практическое исследование, подтверждающее ее эффективность для обучения различным предметам в средних классах школы.

Un maestro de ciencias de quinto grado y un investigador universitario ponen en tela de juicio la idea que la lectura de textos sigue la misma fórmula arcaica: Leer el texto y contestar preguntas al final de la sección. Juntos, ellos adaptaron los roles de círculos de lectura para conformarlos a la estructura del texto, resultando en una estrategia que denominaron Textmasters. Este artículo describe la estrategia junto con el proyecto de investigación que prueba su eficacia en el área de contenido del salón de clase a nivel intermedio.
Evaluation and Management of Syncope
Authors: Thanavaro Joanne L.
Published: September 2009

Syncope is a transient loss of consciousness precipitated by cerebral hypoperfusion, which is associated with a brief absence of postural tone and usually followed by a complete recovery. This clinical condition is a common medical problem and may be attributed to a multitude of disease processes. Risk stratification identifies the safest setting for the initial evaluation as well as which patients are most likely to have a life-threatening event. Establishing the diagnosis of syncope is important so that specific treatment can be instituted to prevent future recurrences and eliminate the underlying predisposing disease. This article reviews the etiology, risk stratification, diagnosis, and therapeutic management of syncope.
Therapeutic Efficacy of Vasoactive Intestinal Peptide inEscherichia coliLipopolysaccharide‐Induced Experimental Periodontitis in Rats
Authors: Gürkan Ali , Emingil Gülnur , Nizam Nejat , Doğanavşargil Başak , Sezak Murat , Kütükçüler Necil , Atilla Gül
Published: September 2009

Background:The aim of the present study was to evaluate the therapeutic efficacy of vasoactive intestinal peptide (VIP), an immunoregulatory molecule, in experimental periodontitis.

Methods:Sixty‐three male Sprague‐Dawley rats were divided into five groups: control; lipopolysaccharide (LPS); LPS + 0.1 nmol VIP; LPS + 1 nmol VIP; and LPS + 10 nmol VIP. Saline was injected into the gingiva of control rats on days 1, 3, and 5, whereas the other groups received injections ofEscherichia coliLPS. VIP groups received intraperitoneal injections of relevant dosages on days 2, 4, 6, 8, and 10. The control and LPS groups were given saline instead of VIP in the same manner. On day 11, serum samples were obtained, and rats were sacrificed. Alveolar bone loss; serum levels of tumor necrosis factor‐alpha, interleukin (IL)‐1β, −10, and −18, soluble receptor activator of nuclear factor‐kappa B ligand (sRANKL), and osteoprotegerin (OPG); and the immune expression of RANKL and OPG were evaluated.

Results:The application of VIP caused a dose‐dependent decline in alveolar bone loss compared to the LPS group, but the differences were not significant (P>0.05). A reduction in the histologic findings of inflammation was observed in all VIP groups. The 1‐ and 10‐nmol VIP groups showed significantly lower serum sRANKL and OPG levels compared to the LPS group (P<0.05). The number of positively stained vessels for endothelial OPG was greater in the 1‐nmol VIP group than in the LPS group (P<0.05).

Conclusion:When periodontitis was induced byE. coliLPS, VIP downregulated the inflammatory response and inhibited alveolar bone loss, possibly by differentially regulating the tissue levels of RANKL and OPG.
Immunohistochemical Analysis of Inducible and Endothelial Forms of Nitric Oxide Synthase in Cyclosporin A‐Induced Gingival Overgrowth
Authors: Gürkan Ali , Emingil Gülnur , Öktem Gülperi , Selvi Nur , Afacan Beral , Tunç İlgenli  , Töz Hüseyin , Atilla Gül
Published: September 2009

Background: The contribution of nitric oxide (NO) to immune response and matrix degradation in the periodontal environment suggests a role for NO and NO‐synthase (NOS) activity in the pathogenesis of cyclosporin A (CsA)‐induced gingival overgrowth (GO). However, current knowledge on this topic is limited to experimental animal studies. The present study was undertaken on the basis of a hypothesis whether altered nitrite/nitrate levels in gingival crevicular fluid (GCF) and endothelial NOS (eNOS) and inducible NOS (iNOS) immunoreactivity in gingiva of CsA‐treated patients contribute to the pathogenesis of CsA‐induced GO.

Methods: Twenty‐four CsA‐medicated renal transplant patients with GO (GO+; n = 12) or without GO (GO−; n = 12), 10 gingivitis, and 10 healthy subjects were included in the study. GCF samples from two proximal sites facing interdental papilla were collected, and papilla was excised. iNOS and eNOS were determined by immunohistochemistry. GCF nitrite/nitrate levels were analyzed based on the Griess reaction.

Results: Weak iNOS immunostaining was observed in the healthy and GO− groups. In the gingivitis and GO+ groups, iNOS immunostaining significantly increased in connective tissue. Epithelial immunostaining of iNOS was localized to basal keratinocytes and the lower layer of stratum (str.) spinosum in the gingivitis group. In the GO+ group, iNOS immunostaining was differentially localized to keratinocytes of str. superficiale but considerably decreased in the str. basale. Weak eNOS immunostaining was found in the healthy and GO− groups, whereas higher immunostaining was observed in the gingivitis and GO+ groups. No intergroup differences were observed regarding nitrite/nitrate levels in GCF.

Conclusion: CsA differentially upregulated iNOS, but not eNOS, in overgrown gingiva, which may play a pivotal role in the pathogenesis of CsA‐induced GO.
Effect of Laser‐Induced Dentin Modifications on Periodontal Fibroblasts and Osteoblasts: A New In Vitro Model
Authors: Galli Carlo , Passeri Giovanni , Cacchioli Antonio , Gualini Giacomo , Ravanetti Francesca , Elezi Erida , Macaluso Guido M.
Published: September 2009

Background: The erbium‐doped:yttrium, aluminum, and garnet (Er:YAG) laser has been shown to be a promising tool for root treatment in periodontitis, but little information is available regarding the surface characteristics after this treatment, mainly because it is difficult to obtain standardized dentin samples for in vitro studies.

Methods: Commercially available standardized dentin disks were treated with an Er:YAG laser at different settings and used as a substrate for human primary osteoblastic cells (hOBs) and periodontal ligament fibroblasts (PLFs). Cell proliferation on untreated dentin was measured by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay after 3, 6, 12, 24, and 48 hours of culture. The effects of the laser on dentin and cell morphology on treated and untreated samples were investigated by scanning electron microscopy after 3, 6, 24, and 48 hours of culture.

Results: Dentin samples supported proliferation for both cell types, although growth kinetics were different. The laser dramatically affected the dentin profile, creating a rough and irregular surface. Cells grew easily on untreated dentin, but fewer cells were present on treated areas, often displaying long filopodes. hOBs showed poorer adhesion to treated dentin than PLFs.

Conclusions: The dentin disks provide a standardized and useful tool to study dentin surface modifications in vitro. PLFs behaved differently from hOBs on dentin, possibly because of their different affinity to this tissue and/or their differentiation state. The changes induced by the laser produced a less favorable environment for cell adhesion or growth, and treated dentin seemed to be more suitable for PLF adhesion compared to hOB adhesion.
Short‐Term Effects of Photodynamic Therapy on Periodontal Status and Glycemic Control of Patients With Diabetes
Authors: Al‐Zahrani Mohammad S. , Bamshmous Shatha O. , Alhassani Ahmed A. , Al‐Sherbini Mossad M.
Published: September 2009

Background: Periodontitis is a major cause of tooth loss among adults. Several studies have shown a possible systemic impact of periodontal infection, including poor glycemic control in patients with diabetes. Recently, photodynamic therapy (PDT) was used to successfully treat periodontal infection. PDT provides a broad spectrum antimicrobial efficacy with no local or systemic side effects. The objective of this study was to examine the effect of the adjunctive use of PDT on periodontal status and glycemic control of patients with diabetes and periodontitis.

Methods: Forty‐five patients with type 2 diabetes and moderate to severe chronic periodontitis were selected and randomly assigned to one of the following three treatment modalities (15 subjects each): scaling and root planing (SRP) only, SRP plus systemic doxycycline, and SRP plus PDT. The plaque and bleeding scores, probing depth, clinical attachment level, and glycosylated hemoglobin (HbA1c) level were recorded at baseline and 3 months after periodontal treatment. Descriptive statistics, the paired t test, and analysis of variance (ANOVA) were used for data analysis.

Results: Statistically significant differences in the mean probing depth, clinical attachment level, plaque deposit, and bleeding on probing were found between baseline and 12 weeks post‐treatment for all groups. No significant differences in periodontal parameters and glucose levels were detected among the three groups. Reduction in the mean HbA1c level after treatment was observed in all groups but was only significant for the SRP plus doxycycline group.

Conclusion: The results of the present study indicate that PDT does not benefit conventional non‐surgical periodontal therapy in patients with diabetes.
Clinical Decisions and the Quality of Evidence Available for Dental Implants
Authors: Bhatavadekar Neel
Published: September 2009

As more types of implants have become available, clinicians have been faced with the task of choosing a specific implant from a wide array of options for a given clinical situation, which has led to an ever‐increasing need for clinical evidence to help clinicians choose an implant. This article highlights the need for clinicians to look beyond the claims proposed by manufacturers because several of those claims are not substantiated by randomized controlled trials but by in vitro data alone. Recent advances in clinical evidence‐based decision portals might enable busy clinicians to adopt an evidence‐based approach to choosing implant systems. Also, the standardization of study‐reporting criteria might enable comparisons across implant systems in the future.
Characteristics and Microbial Succession in Co-Composting of Oil Palm Empty Fruit Bunch and Partially Treated Palm Oil Mill Effluent
Authors: Baharuddin Azhari Samsu , Kazunori Nakamura , Abd-Aziz Suraini , Tabatabaei Meisam , Rahman Nor’ Aini Abdul , Ali Hassan Mohd , Wakisaka Minato , Sakai Kenji , Shirai Yoshihito
Published: September 2009

Microbial communities and cellulolytic enzymes activities were analyzed during the co-composting of empty
fruit bunch (EFB) and partially treated palm oil mill effluent (POME) in pilot scale. The physicochemical parameters
were also measured during the composting. The diversity of the bacterial community was investigated using polymerase
chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results indicated that the composting process of
EFB with partially treated POME was dominated by uncultured bacteria species. The dominant bacterial group changed
from the phylum proteobacteria in the thermophilic stage to the phylum chloroflexi in the maturing stage. Scanning electron
microscope (SEM) analysis exhibited the significant degradation of EFB structure during the composting process.
The maximum cellulase activity for carboxymethylcellulase (CMCase), filter paperase (FPase) and β-glucosidase were
13.6, 4.1 and 20.3 U/g of dry substrate, respectively at day 30 of composting. The results of this study significantly contributed
to a better understanding of mechanisms involved in co-composting process in pilot scale.
Bioactive Alkaloids from South American Psychotria and Related Species
Authors: Porto Diogo D. , Henriques Amélia T. , Fett-Neto Arthur G.
Published: September 2009

Many important molecules have been discovered from tropical and sub-tropical plant biodiversity. However, the largest part of the chemical profile of such biodiversity remains unknown. Combining ethnopharmacological and chemotaxonomical investigation can be a good strategy in bioactive compound discovery. South American Psychotria species studied by this approach proved to be a rich source of new bioactive alkaloids, some of which bear unique chemical skeletons.
Effect of season, breed and age on the quality of boar sperm 1: The native sperm
Authors: Stancic Blagoje , Gagrcin Mladen , Radovic Ivan
Published: September 2009

Total of 182 ejaculates were investigated in regard to the effect of season breed and age on the quality of boar sperm. The boars of Yorkshire Landrace, Duroc, Hempshire and Pietrain pure breeds and Fr crossbred pigs were divided according to age in four groups: 12, 13-18, 19-24 and 25 months. Ejaculates were examined in the following seasons: January-March April-June, July-September and October-December. Differences in ejaculate volume, total number, concentration and progressive motility (PM), as well as number of ejaculates with less then 65% PM, were estimated within seasons, breeds and age of boars. These results suggest that quality of every single ejaculate must be evaluated before using for AI.
Effects of α-tocopheryl acetate addition to the chicken feed on the sensory characteristics and α - tocopherol content in meat
Authors: Mandic Anamarija , Pavlovic Aleksandra , Dzinic Natalija , Popov-Raljic Jovanka , Kelemen-Masic Djurdjica
Published: September 2009

Effects of ? -tocopheryl acetate addition to the chicken feed (A-control group: common broiler feed, B and C groups: feed supplemented with a-tocopheryl acetate at 50 mg/kg and 75 mg/kg of feed, respectively) on sensory characteristics of meat of chicken breasts have been investigated as well as the content of vitamin E, expressed as a- tocopherol, in liver thigh muscle, and meat of chicken breasts. Sensory characteristics (colour, texture, tenderness and juiciness, odour and flavor) of thermally treated meat samples have been evaluated by analytical-descriptive (point) system. Regarding obtained results, it can be noticed that the color of samples scored with high grades, has been almost unvarying between samples. Tenderness as the quality of texture and juiciness has been evaluated using oral technique. Samples of groups Band C have been qualified as the most tender. Samples of group A have been slightly less tender. The juiciest samples have been of group C, followed by samples of group B and group A. Flavor of thermally treated chicken meat breast samples has been evaluated true the taste and odour characteristics (Popov-Raljic i Radovanovic, 2001) The most intensively expressed characteristic taste and odour have the samples of group A, and have been given the highest grade, while the similar grades have been given to group C samples. Also, content of vitamin E expressed as ? -tocopherol has been determined by reverse phase high-performance liquid chromatography (HPLC) method, with DAD detector on 295 nm. Results of chicken tissues study show that: content of (l-tocopherol in liver is always greater than in thigh muscle, greater than in meat of chicken breasts. Content of ? -tocopherol increased 4.17 times in meat of chicken breasts, 3.87 times in thigh muscle and 1.82 times in liver when the chicks were fed 42 days with feed supplemented with 50 mg (? -tocopheryl acetate/1 kg diet (B group). Further increase in tissues has been obtained by feed that contained 75 mg (? -tocopheryl acetate/1 kg diet (C group): 2.6 times has been greater content of ? -tocopherol in thigh muscle, 2.27 times in chick breast meat samples, 1.14 times in liver when comparing to group A. Finally, regarding all the results, the best final score for sensory evaluation of appearance, texture and flavour has been given to group B (28.25), and very similar scores, slightly lower, for group A (27. 50) and group C (27.80). HPLC results clearly indicate that ? -tocopherol content is elevated by dietary supplementation in all investigated chicken organs and is always greater in liver than in thigh muscle and in meat of chicken breasts, which improves its efficient absorption in investigated range.